Exemple #1
0
END_TEST

START_TEST(test_pbuf_queueing_bigger_than_64k)
{
  int i;
  err_t err;
  struct pbuf *p1, *p2, *p3, *rest2=NULL, *rest3=NULL;
  LWIP_UNUSED_ARG(_i);

  for(i = 0; i < TESTBUFSIZE_1; i++) {
    testbuf_1[i] = (u8_t)rand();
  }
  for(i = 0; i < TESTBUFSIZE_2; i++) {
    testbuf_2[i] = (u8_t)rand();
  }
  for(i = 0; i < TESTBUFSIZE_3; i++) {
    testbuf_3[i] = (u8_t)rand();
  }

  p1 = pbuf_alloc(PBUF_RAW, TESTBUFSIZE_1, PBUF_POOL);
  fail_unless(p1 != NULL);
  p2 = pbuf_alloc(PBUF_RAW, TESTBUFSIZE_2, PBUF_POOL);
  fail_unless(p2 != NULL);
  p3 = pbuf_alloc(PBUF_RAW, TESTBUFSIZE_3, PBUF_POOL);
  fail_unless(p3 != NULL);
  err = pbuf_take(p1, testbuf_1, TESTBUFSIZE_1);
  fail_unless(err == ERR_OK);
  err = pbuf_take(p2, testbuf_2, TESTBUFSIZE_2);
  fail_unless(err == ERR_OK);
  err = pbuf_take(p3, testbuf_3, TESTBUFSIZE_3);
  fail_unless(err == ERR_OK);

  pbuf_cat(p1, p2);
  pbuf_cat(p1, p3);

  pbuf_split_64k(p1, &rest2);
  fail_unless(p1->tot_len == TESTBUFSIZE_1);
  fail_unless(rest2->tot_len == (u16_t)((TESTBUFSIZE_2+TESTBUFSIZE_3) & 0xFFFF));
  pbuf_split_64k(rest2, &rest3);
  fail_unless(rest2->tot_len == TESTBUFSIZE_2);
  fail_unless(rest3->tot_len == TESTBUFSIZE_3);

  pbuf_copy_partial(p1, testbuf_1a, TESTBUFSIZE_1, 0);
  pbuf_copy_partial(rest2, testbuf_2a, TESTBUFSIZE_2, 0);
  pbuf_copy_partial(rest3, testbuf_3a, TESTBUFSIZE_3, 0);
  for(i = 0; i < TESTBUFSIZE_1; i++)
    fail_unless(testbuf_1[i] == testbuf_1a[i]);
  for(i = 0; i < TESTBUFSIZE_2; i++)
    fail_unless(testbuf_2[i] == testbuf_2a[i]);
  for(i = 0; i < TESTBUFSIZE_3; i++)
    fail_unless(testbuf_3[i] == testbuf_3a[i]);

  pbuf_free(p1);
  pbuf_free(rest2);
  pbuf_free(rest3);
}
static uint16_t populate_record(const char *name,
                                uint16_t qtype, uint16_t qclass,
                                uint32_t ttl, const void *data,
                                uint16_t datalen,
                                struct pbuf *dest)
{
    int title_len = special_strlen(name);
    int msglen = title_len  + sizeof(struct record) + datalen;
    struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, msglen, PBUF_RAM);

    memcpy(p->payload, name, title_len);
    char *end = ((char *)p->payload) + title_len;

    struct record *rec = (struct record *) end;
    rec->qtype = htons(qtype);
    rec->qclass = htons(qclass);
    rec->ttl = htonl(ttl);
    rec->data_length = htons(datalen);
    memcpy(rec->data, data, datalen);

    uint16_t ret = dest->tot_len + title_len + sizeof(*rec);

    pbuf_cat(dest, p);

    return htons(DATA_POINTER | ret);
}
static void rx_core(struct socket * s, struct pbuf *p) {
    /** NOTE: the receive callback for both UDP and TCP are responsible for deallocating pbufs, so there is no call to
     *  pbuf_ref() required here.
     */
    __disable_irq();
    if (s->rxBufChain == NULL) {
        s->rxBufChain = p;
    } else {
        struct pbuf * q = (struct pbuf *)s->rxBufChain;
        switch(s->family) {
            case SOCKET_DGRAM:
                // find the last element of the buffer chain.
                while (q->next) {q = q->next;}
                /**
                 * Attach p to it wihout changing the tot_len of the buffer chain
                 * NOTE: This is not how pbufs are intended to work, but it is necessary to deal with a) fragmentation
                 * and b) packet queueing
                 */
                q->next = p;
                break;
            case SOCKET_STREAM:
                pbuf_cat((struct pbuf *) s->rxBufChain, p);
                break;
        }
    }
    __enable_irq();
}
// Callback for inbound tcp packets.
STATIC err_t _lwip_tcp_recv(void *arg, struct tcp_pcb *tcpb, struct pbuf *p, err_t err) {
    lwip_socket_obj_t *socket = (lwip_socket_obj_t*)arg;

    if (p == NULL) {
        // Other side has closed connection.
        DEBUG_printf("_lwip_tcp_recv[%p]: other side closed connection\n", socket);
        socket->state = STATE_PEER_CLOSED;
        exec_user_callback(socket);
        return ERR_OK;
    }

    if (socket->incoming.pbuf == NULL) {
        socket->incoming.pbuf = p;
    } else {
        #ifdef SOCKET_SINGLE_PBUF
        return ERR_BUF;
        #else
        pbuf_cat(socket->incoming.pbuf, p);
        #endif
    }

    exec_user_callback(socket);

    return ERR_OK;
}
Exemple #5
0
/**
 * Chain two pbufs (or pbuf chains) together.
 * 
 * The caller MUST call pbuf_free(t) once it has stopped
 * using it. Use pbuf_cat() instead if you no longer use t.
 * 
 * @param h head pbuf (chain)
 * @param t tail pbuf (chain)
 * @note The pbufs MUST belong to the same packet.
 * @note MAY NOT be called on a packet queue.
 *
 * The ->tot_len fields of all pbufs of the head chain are adjusted.
 * The ->next field of the last pbuf of the head chain is adjusted.
 * The ->ref field of the first pbuf of the tail chain is adjusted.
 *
 */
void
pbuf_chain(struct pbuf *h, struct pbuf *t)
{
  pbuf_cat(h, t);
  /* t is now referenced by h */
  pbuf_ref(t);
  LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t));
}
Exemple #6
0
static void save_until_animated(acc_pend_t *pend, struct pbuf *data)
{
	tcp_recved(pend->pcb, data->tot_len);

	if (pend->ante == 0)
		pend->ante = data;
	else
		pbuf_cat(pend->ante, data);
}
static void rx_core(struct socket * s, struct pbuf *p) {

    __disable_irq();
    if (s->rxBufChain == NULL) {
        s->rxBufChain = p;
    } else {
        pbuf_cat((struct pbuf *) s->rxBufChain, p);
    }
    __enable_irq();
}
Exemple #8
0
static err_t
tcpecho_raw_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
  struct tcpecho_raw_state *es;
  err_t ret_err;

  LWIP_ASSERT("arg != NULL",arg != NULL);
  es = (struct tcpecho_raw_state *)arg;
  if (p == NULL) {
    /* remote host closed connection */
    es->state = ES_CLOSING;
    if(es->p == NULL) {
      /* we're done sending, close it */
      tcpecho_raw_close(tpcb, es);
    } else {
      /* we're not done yet */
      tcpecho_raw_send(tpcb, es);
    }
    ret_err = ERR_OK;
  } else if(err != ERR_OK) {
    /* cleanup, for unknown reason */
    if (p != NULL) {
      pbuf_free(p);
    }
    ret_err = err;
  }
  else if(es->state == ES_ACCEPTED) {
    /* first data chunk in p->payload */
    es->state = ES_RECEIVED;
    /* store reference to incoming pbuf (chain) */
    es->p = p;
    tcpecho_raw_send(tpcb, es);
    ret_err = ERR_OK;
  } else if (es->state == ES_RECEIVED) {
    /* read some more data */
    if(es->p == NULL) {
      es->p = p;
      tcpecho_raw_send(tpcb, es);
    } else {
      struct pbuf *ptr;

      /* chain pbufs to the end of what we recv'ed previously  */
      ptr = es->p;
      pbuf_cat(ptr,p);
    }
    ret_err = ERR_OK;
  } else {
    /* unkown es->state, trash data  */
    tcp_recved(tpcb, p->tot_len);
    pbuf_free(p);
    ret_err = ERR_OK;
  }
  return ret_err;
}
Exemple #9
0
static err_t net_server_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
{
    struct net_server_connstate *cs;

    cs = (struct net_server_connstate *)arg;
    if(p) {
        if(cs->rp)
            pbuf_cat(cs->rp, p);
        else {
            cs->rp = p;
            cs->rp_offset = 0;
        }
    } else
        net_server_close(cs, pcb);
    return ERR_OK;
}
Exemple #10
0
err_t EthernetClient::do_recv(void *arg, struct tcp_pcb *cpcb, struct pbuf *p, err_t err)
{
	/*
	 * Get the client object from the argument
	 * to get access to variables and functions
	 */
	EthernetClient *client = static_cast<EthernetClient*>(arg);

	if(p == 0) {
		client->_connected = false;
		return ERR_OK;
	}

	if(client->cs->p != 0)
		pbuf_cat(client->cs->p, p);
	else
		client->cs->p = p;

	return ERR_OK;
}
Exemple #11
0
err_t LwipNetTcpSocket::recvCb(tcp_pcb* tpcb, pbuf *p, err_t err)
{
  //Store pbuf ptr
 // DBG("Receive CB with err = %d & len = %d.\n", err, p->tot_len);
//  tcp_recved( (tcp_pcb*) m_pPcb, p->tot_len); //Acknowledge the reception
  
  if(err)
  {
    queueEvent(NETTCPSOCKET_ERROR);
    return ERR_OK; //FIXME: More robust error handling there
  }
  else if(!p)
  {
    DBG("NetTcpSocket %p - Connection closed by remote host (LwipNetTcpSocket::recvCb).\n", (void*)this);
    //Buf is NULL, that means that the connection has been closed by remote host
    
    //FIX: 27/05/2010: We do not want to deallocate the socket while some data might still be readable
    //REMOVED:   close();
 
    //However we do not want to close the socket yet
 
    queueEvent(NETTCPSOCKET_DISCONNECTED);
    return ERR_OK; 
  }
  
  //We asserted that p is a valid pointer

  //New data processing
  tcp_recved( tpcb, p->tot_len); //Acknowledge the reception
  if(!m_pReadPbuf)
  {
    m_pReadPbuf = p;
    queueEvent(NETTCPSOCKET_READABLE);
  }
  else
  {
    pbuf_cat((pbuf*)m_pReadPbuf, p); //m_pReadPbuf is not empty, tail p to it and drop our ref
    //No need to queue an event in that case since the read buf has not been processed yet
  }
  return ERR_OK;
}
Exemple #12
0
static err_t test_tcp_netif_output(struct netif *netif, struct pbuf *p,
       ip_addr_t *ipaddr)
{
  struct test_tcp_txcounters *txcounters = (struct test_tcp_txcounters*)netif->state;
  LWIP_UNUSED_ARG(ipaddr);
  txcounters->num_tx_calls++;
  txcounters->num_tx_bytes += p->tot_len;
  if (txcounters->copy_tx_packets) {
    struct pbuf *p_copy = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
    err_t err;
    EXPECT(p_copy != NULL);
    err = pbuf_copy(p_copy, p);
    EXPECT(err == ERR_OK);
    if (txcounters->tx_packets == NULL) {
      txcounters->tx_packets = p_copy;
    } else {
      pbuf_cat(txcounters->tx_packets, p_copy);
    }
  }
  return ERR_OK;
}
void LwipNetUdpSocket::recvCb(udp_pcb* pcb, struct pbuf* p, ip_addr_t* addr, u16_t port)
{
  DBG(" Packet of length %d arrived in UDP Socket.\r\n", p->tot_len);
  list<InPacket>::iterator it;
  for ( it = m_lInPkt.begin(); it != m_lInPkt.end(); it++ )
  {
    if( ip_addr_cmp((&((*it).addr)), addr) && ((*it).port == port) )
    {
      //Let's tail this packet to the previous one
      pbuf_cat((pbuf*)((*it).pBuf), p);
      //No need to queue an event in that case since the read buf has not been processed yet
      return;
    }
  }

  //New host, add a packet to the queue
  InPacket pkt;
  pkt.pBuf = p;
  pkt.addr = *addr;
  pkt.port = port;
  m_lInPkt.push_back(pkt);

  queueEvent(NETUDPSOCKET_READABLE);
}
Exemple #14
0
static struct pbuf* low_level_input(struct netif *netif) {
    u16_t l, temp_l;
    struct pbuf *first_pbuf, *next_pbuf, *q;
    u16_t len;
#ifdef ENET_LITTLE_ENDIAN
    u8_t *data_temp;
#endif
    u8_t more_pkts = 1, processing_error = 0;
    
    (void)netif;
    
    /* initial pkt handling */
    if (!(rx_bd[rx_next_buf].status & ENET_RX_BD_E)) {       /* if pkt is filled */
        if (rx_bd[rx_next_buf].status & ENET_RX_BD_L) {
            more_pkts = 0;
            if (rx_bd[rx_next_buf].status & (ENET_RX_BD_LG | ENET_RX_BD_NO | ENET_RX_BD_CR | ENET_RX_BD_OV)) {
                /* bad packet */
                LINK_STATS_INC(link.memerr);
                LINK_STATS_INC(link.drop);
                goto EXIT_RX_PKT;
            }
            else {
#ifdef ENET_LITTLE_ENDIAN
                len = __REVSH(rx_bd[rx_next_buf].length);
#else
                len = rx_bd[rx_next_buf].length;
#endif 
                LINK_STATS_INC(link.recv);
            }
        }
        else /* if not L bit, then buffer's length */
            len = ENET_RX_BUF_SIZE;
        
        if ((first_pbuf = pbuf_alloc(PBUF_RAW, len, PBUF_POOL)) != NULL) {
            /* get data */
            l = 0;
            temp_l = 0;        
            /* We iterate over the pbuf chain until we have read the entire
            * packet into the pbuf. */
            for (q = first_pbuf; q != NULL; q = q->next) {
                /* Read enough bytes to fill this pbuf in the chain. The
                * available data in the pbuf is given by the q->len
                * variable.
                * This does not necessarily have to be a memcpy, you can also preallocate
                * pbufs for a DMA-enabled MAC and after receiving truncate it to the
                * actually received size. In this case, ensure the tot_len member of the
                * pbuf is the sum of the chained pbuf len members.
                */
                temp_l = LWIP_MIN(len, LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE));
#ifdef ENET_LITTLE_ENDIAN
                data_temp = (u8_t *)__REV((u32_t)rx_bd[ rx_next_buf ].data);
                memcpy((u8_t*)q->payload, &( data_temp[l] ), temp_l);
#else
                memcpy((u8_t*)q->payload, &( rx_bd[ rx_next_buf ].data[l] ), temp_l);
#endif
                l += temp_l;
                len -= temp_l;
            }
        }
        else {
            /* bad buffers */
            LINK_STATS_INC(link.memerr);
            LINK_STATS_INC(link.drop);
            processing_error = 1;
        }
        
    EXIT_RX_PKT:
        rx_bd[rx_next_buf++].status |= ENET_RX_BD_E; /* consumed pkt */
        ENET_RDAR = ENET_RDAR_RDAR_MASK;
        if (rx_next_buf >= NUM_ENET_RX_BUFS)
            rx_next_buf = 0;
    }
    else
        return (struct pbuf*)NULL;      /* special NULL case */
    
    /* more pkts handling */
    while (more_pkts) {
       //if(!(rx_bd[ rx_next_buf ].status & RX_BD_E) )
       ///*if pkt is filled*/
       //{
        if (rx_bd[rx_next_buf].status & ENET_RX_BD_L) {
            more_pkts = 0; 
            if (rx_bd[rx_next_buf].status & (ENET_RX_BD_LG | ENET_RX_BD_NO | ENET_RX_BD_CR | ENET_RX_BD_OV)) {
                /* bad packet */
                LINK_STATS_INC(link.memerr);
                LINK_STATS_INC(link.drop);
                goto EXIT_RX_PKT2;
            }
            else {
#ifdef ENET_LITTLE_ENDIAN
                len = __REVSH(rx_bd[rx_next_buf].length);
#else
                len = rx_bd[rx_next_buf].length;
#endif
                /* buffer with L bit has total frame's length instead of remaining bytes from frame's lenght */
                len %= ENET_RX_BUF_SIZE;
                LINK_STATS_INC(link.recv);
            }
        }
        else /* if not L bit, then buffer's length */
            len = ENET_RX_BUF_SIZE;
        
        if (((next_pbuf = pbuf_alloc(PBUF_RAW, len, PBUF_POOL)) != NULL) && (!processing_error)) {
            /* get data */
            l = 0;
            temp_l = 0;        
            /* We iterate over the pbuf chain until we have read the entire
            * packet into the pbuf. */
            for (q = next_pbuf; q != NULL; q = q->next) {
                /* Read enough bytes to fill this pbuf in the chain. The
                * available data in the pbuf is given by the q->len
                * variable.
                * This does not necessarily have to be a memcpy, you can also preallocate
                * pbufs for a DMA-enabled MAC and after receiving truncate it to the
                * actually received size. In this case, ensure the tot_len member of the
                * pbuf is the sum of the chained pbuf len members.
                */
                temp_l = LWIP_MIN(len, LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE));
#ifdef ENET_LITTLE_ENDIAN
                data_temp = (u8_t *)__REV((u32_t)rx_bd[rx_next_buf].data);
                memcpy((u8_t*)q->payload, &(data_temp[l]), temp_l);
#else
                memcpy((u8_t*)q->payload, &(rx_bd[rx_next_buf].data[l] ), temp_l);
#endif
                l += temp_l;
                len -= temp_l;
            }
            
            /* link pbufs */
            pbuf_cat(first_pbuf, next_pbuf);
        }
        else {
            /* bad buffer - out of lwip buffers */
            LINK_STATS_INC(link.memerr);
            LINK_STATS_INC(link.drop);
            processing_error = 1;
        }
    EXIT_RX_PKT2:
        rx_bd[rx_next_buf++].status |= ENET_RX_BD_E; /* consumed pkt */
        ENET_RDAR = ENET_RDAR_RDAR_MASK;
        if (rx_next_buf >= NUM_ENET_RX_BUFS)
            rx_next_buf = 0;  
    }
    
    return first_pbuf;
}
Exemple #15
0
/* Helper function that processes rx application data stored in rx pbuf chain */
static err_t
altcp_mbedtls_handle_rx_appldata(struct altcp_pcb *conn, altcp_mbedtls_state_t *state)
{
  int ret;
  LWIP_ASSERT("state != NULL", state != NULL);
  if (!(state->flags & ALTCP_MBEDTLS_FLAGS_HANDSHAKE_DONE)) {
    /* handshake not done yet */
    return ERR_VAL;
  }
  do {
    /* allocate a full-sized unchained PBUF_POOL: this is for RX! */
    struct pbuf *buf = pbuf_alloc(PBUF_RAW, PBUF_POOL_BUFSIZE, PBUF_POOL);
    if (buf == NULL) {
      /* We're short on pbufs, try again later from 'poll' or 'recv' callbacks.
         @todo: close on excessive allocation failures or leave this up to upper conn? */
      return ERR_OK;
    }

    /* decrypt application data, this pulls encrypted RX data off state->rx pbuf chain */
    ret = mbedtls_ssl_read(&state->ssl_context, (unsigned char *)buf->payload, PBUF_POOL_BUFSIZE);
    if (ret < 0) {
      if (ret == MBEDTLS_ERR_SSL_CLIENT_RECONNECT) {
        /* client is initiating a new connection using the same source port -> close connection or make handshake */
        LWIP_DEBUGF(ALTCP_MBEDTLS_DEBUG, ("new connection on same source port\n"));
        LWIP_ASSERT("TODO: new connection on same source port, close this connection", 0);
      } else if ((ret != MBEDTLS_ERR_SSL_WANT_READ) && (ret != MBEDTLS_ERR_SSL_WANT_WRITE)) {
        if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) {
          LWIP_DEBUGF(ALTCP_MBEDTLS_DEBUG, ("connection was closed gracefully\n"));
        } else if (ret == MBEDTLS_ERR_NET_CONN_RESET) {
          LWIP_DEBUGF(ALTCP_MBEDTLS_DEBUG, ("connection was reset by peer\n"));
        }
        pbuf_free(buf);
        return ERR_OK;
      } else {
        pbuf_free(buf);
        return ERR_OK;
      }
      pbuf_free(buf);
      altcp_abort(conn);
      return ERR_ABRT;
    } else {
      err_t err;
      if (ret) {
        LWIP_ASSERT("bogus receive length", ret <= PBUF_POOL_BUFSIZE);
        /* trim pool pbuf to actually decoded length */
        pbuf_realloc(buf, (u16_t)ret);

        state->bio_bytes_appl += ret;
        if (mbedtls_ssl_get_bytes_avail(&state->ssl_context) == 0) {
          /* Record is done, now we know the share between application and protocol bytes
             and can adjust the RX window by the protocol bytes.
             The rest is 'recved' by the application calling our 'recved' fn. */
          int overhead_bytes;
          LWIP_ASSERT("bogus byte counts", state->bio_bytes_read > state->bio_bytes_appl);
          overhead_bytes = state->bio_bytes_read - state->bio_bytes_appl;
          altcp_mbedtls_lower_recved(conn->inner_conn, overhead_bytes);
          state->bio_bytes_read = 0;
          state->bio_bytes_appl = 0;
        }

        if (state->rx_app == NULL) {
          state->rx_app = buf;
        } else {
          pbuf_cat(state->rx_app, buf);
        }
      } else {
        pbuf_free(buf);
        buf = NULL;
      }
      err = altcp_mbedtls_pass_rx_data(conn, state);
      if (err != ERR_OK) {
        if (err == ERR_ABRT) {
          /* recv callback needs to return this as the pcb is deallocated */
          return ERR_ABRT;
        }
        /* we hide all other errors as we retry feeding the pbuf to the app later */
        return ERR_OK;
      }
    }
  } while (ret > 0);
  return ERR_OK;
}
Exemple #16
0
/** Recv callback from lower connection (i.e. TCP)
 * This one mainly differs between connection setup/handshake (data is fed into mbedTLS only)
 * and application phase (data is decoded by mbedTLS and passed on to the application).
 */
static err_t
altcp_mbedtls_lower_recv(void *arg, struct altcp_pcb *inner_conn, struct pbuf *p, err_t err)
{
  altcp_mbedtls_state_t *state;
  struct altcp_pcb *conn = (struct altcp_pcb *)arg;

  LWIP_ASSERT("no err expected", err == ERR_OK);
  LWIP_UNUSED_ARG(err);

  if (!conn) {
    /* no connection given as arg? should not happen, but prevent pbuf/conn leaks */
    if (p != NULL) {
      pbuf_free(p);
    }
    altcp_close(inner_conn);
    return ERR_CLSD;
  }
  state = (altcp_mbedtls_state_t *)conn->state;
  LWIP_ASSERT("pcb mismatch", conn->inner_conn == inner_conn);
  if (!state) {
    /* already closed */
    if (p != NULL) {
      pbuf_free(p);
    }
    altcp_close(inner_conn);
    return ERR_CLSD;
  }

  /* handle NULL pbuf (inner connection closed) */
  if (p == NULL) {
    /* remote host sent FIN, remember this (SSL state is destroyed
        when both sides are closed only!) */
    if ((state->flags & (ALTCP_MBEDTLS_FLAGS_HANDSHAKE_DONE | ALTCP_MBEDTLS_FLAGS_UPPER_CALLED)) ==
        (ALTCP_MBEDTLS_FLAGS_HANDSHAKE_DONE | ALTCP_MBEDTLS_FLAGS_UPPER_CALLED)) {
      /* need to notify upper layer (e.g. 'accept' called or 'connect' succeeded) */
      if ((state->rx != NULL) || (state->rx_app != NULL)) {
        state->flags |= ALTCP_MBEDTLS_FLAGS_RX_CLOSE_QUEUED;
        /* this is a normal close (FIN) but we have unprocessed data, so delay the FIN */
        altcp_mbedtls_handle_rx_appldata(conn, state);
        return ERR_OK;
      }
      state->flags |= ALTCP_MBEDTLS_FLAGS_RX_CLOSED;
      if (conn->recv) {
        return conn->recv(conn->arg, conn, NULL, ERR_OK);
      }
    } else {
      /* before connection setup is done: call 'err' */
      if (conn->err) {
        conn->err(conn->arg, ERR_CLSD);
      }
      altcp_close(conn);
    }
    return ERR_OK;
  }

  /* If we come here, the connection is in good state (handshake phase or application data phase).
     Queue up the pbuf for processing as handshake data or application data. */
  if (state->rx == NULL) {
    state->rx = p;
  } else {
    LWIP_ASSERT("rx pbuf overflow", (int)p->tot_len + (int)p->len <= 0xFFFF);
    pbuf_cat(state->rx, p);
  }
  return altcp_mbedtls_lower_recv_process(conn, state);
}
Exemple #17
0
/**
 * Fragment an IPv6 datagram if too large for the netif or path MTU.
 *
 * Chop the datagram in MTU sized chunks and send them in order
 * by pointing PBUF_REFs into p
 *
 * @param p ipv6 packet to send
 * @param netif the netif on which to send
 * @param dest destination ipv6 address to which to send
 *
 * @return ERR_OK if sent successfully, err_t otherwise
 */
err_t
ip6_frag(struct pbuf *p, struct netif *netif, const ip6_addr_t *dest)
{
  struct ip6_hdr *original_ip6hdr;
  struct ip6_hdr *ip6hdr;
  struct ip6_frag_hdr *frag_hdr;
  struct pbuf *rambuf;
#if !LWIP_NETIF_TX_SINGLE_PBUF
  struct pbuf *newpbuf;
  u16_t newpbuflen = 0;
  u16_t left_to_copy;
#endif
  static u32_t identification;
  u16_t nfb;
  u16_t left, cop;
  u16_t mtu;
  u16_t fragment_offset = 0;
  u16_t last;
  u16_t poff = IP6_HLEN;

  identification++;

  original_ip6hdr = (struct ip6_hdr *)p->payload;

  mtu = nd6_get_destination_mtu(dest, netif);

  /* @todo we assume there are no options in the unfragmentable part (IPv6 header). */
  left = p->tot_len - IP6_HLEN;

  nfb = (mtu - (IP6_HLEN + IP6_FRAG_HLEN)) & IP6_FRAG_OFFSET_MASK;

  while (left) {
    last = (left <= nfb);

    /* Fill this fragment */
    cop = last ? left : nfb;

#if LWIP_NETIF_TX_SINGLE_PBUF
    rambuf = pbuf_alloc(PBUF_IP, cop + IP6_FRAG_HLEN, PBUF_RAM);
    if (rambuf == NULL) {
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      return ERR_MEM;
    }
    LWIP_ASSERT("this needs a pbuf in one piece!",
      (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
    poff += pbuf_copy_partial(p, (u8_t*)rambuf->payload + IP6_FRAG_HLEN, cop, poff);
    /* make room for the IP header */
    if (pbuf_header(rambuf, IP6_HLEN)) {
      pbuf_free(rambuf);
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      return ERR_MEM;
    }
    /* fill in the IP header */
    SMEMCPY(rambuf->payload, original_ip6hdr, IP6_HLEN);
    ip6hdr = (struct ip6_hdr *)rambuf->payload;
    frag_hdr = (struct ip6_frag_hdr *)((u8_t*)rambuf->payload + IP6_HLEN);
#else
    /* When not using a static buffer, create a chain of pbufs.
     * The first will be a PBUF_RAM holding the link, IPv6, and Fragment header.
     * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
     * but limited to the size of an mtu.
     */
    rambuf = pbuf_alloc(PBUF_LINK, IP6_HLEN + IP6_FRAG_HLEN, PBUF_RAM);
    if (rambuf == NULL) {
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      return ERR_MEM;
    }
    LWIP_ASSERT("this needs a pbuf in one piece!",
                (p->len >= (IP6_HLEN)));
    SMEMCPY(rambuf->payload, original_ip6hdr, IP6_HLEN);
    ip6hdr = (struct ip6_hdr *)rambuf->payload;
    frag_hdr = (struct ip6_frag_hdr *)((u8_t*)rambuf->payload + IP6_HLEN);

    /* Can just adjust p directly for needed offset. */
    p->payload = (u8_t *)p->payload + poff;
    p->len -= poff;
    p->tot_len -= poff;

    left_to_copy = cop;
    while (left_to_copy) {
      struct pbuf_custom_ref *pcr;
      newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
      /* Is this pbuf already empty? */
      if (!newpbuflen) {
        p = p->next;
        continue;
      }
      pcr = ip6_frag_alloc_pbuf_custom_ref();
      if (pcr == NULL) {
        pbuf_free(rambuf);
        IP6_FRAG_STATS_INC(ip6_frag.memerr);
        return ERR_MEM;
      }
      /* Mirror this pbuf, although we might not need all of it. */
      newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
      if (newpbuf == NULL) {
        ip6_frag_free_pbuf_custom_ref(pcr);
        pbuf_free(rambuf);
        IP6_FRAG_STATS_INC(ip6_frag.memerr);
        return ERR_MEM;
      }
      pbuf_ref(p);
      pcr->original = p;
      pcr->pc.custom_free_function = ip6_frag_free_pbuf_custom;

      /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
       * so that it is removed when pbuf_dechain is later called on rambuf.
       */
      pbuf_cat(rambuf, newpbuf);
      left_to_copy -= newpbuflen;
      if (left_to_copy) {
        p = p->next;
      }
    }
    poff = newpbuflen;
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */

    /* Set headers */
    frag_hdr->_nexth = original_ip6hdr->_nexth;
    frag_hdr->reserved = 0;
    frag_hdr->_fragment_offset = lwip_htons((fragment_offset & IP6_FRAG_OFFSET_MASK) | (last ? 0 : IP6_FRAG_MORE_FLAG));
    frag_hdr->_identification = lwip_htonl(identification);

    IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_FRAGMENT);
    IP6H_PLEN_SET(ip6hdr, cop + IP6_FRAG_HLEN);

    /* No need for separate header pbuf - we allowed room for it in rambuf
     * when allocated.
     */
    IP6_FRAG_STATS_INC(ip6_frag.xmit);
    netif->output_ip6(netif, rambuf, dest);

    /* Unfortunately we can't reuse rambuf - the hardware may still be
     * using the buffer. Instead we free it (and the ensuing chain) and
     * recreate it next time round the loop. If we're lucky the hardware
     * will have already sent the packet, the free will really free, and
     * there will be zero memory penalty.
     */

    pbuf_free(rambuf);
    left -= cop;
    fragment_offset += cop;
  }
  return ERR_OK;
}
Exemple #18
0
/**
 * Reassembles incoming IPv6 fragments into an IPv6 datagram.
 *
 * @param p points to the IPv6 Fragment Header
 * @return NULL if reassembly is incomplete, pbuf pointing to
 *         IPv6 Header if reassembly is complete
 */
struct pbuf *
ip6_reass(struct pbuf *p)
{
  struct ip6_reassdata *ipr, *ipr_prev;
  struct ip6_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
  struct ip6_frag_hdr *frag_hdr;
  u16_t offset, len;
  u16_t clen;
  u8_t valid = 1;
  struct pbuf *q;

  IP6_FRAG_STATS_INC(ip6_frag.recv);

  if ((const void*)ip6_current_header() != ((u8_t*)p->payload) - IP6_HLEN) {
    /* ip6_frag_hdr must be in the first pbuf, not chained */
    IP6_FRAG_STATS_INC(ip6_frag.proterr);
    IP6_FRAG_STATS_INC(ip6_frag.drop);
    goto nullreturn;
  }

  frag_hdr = (struct ip6_frag_hdr *) p->payload;

  clen = pbuf_clen(p);

  offset = lwip_ntohs(frag_hdr->_fragment_offset);

  /* Calculate fragment length from IPv6 payload length.
   * Adjust for headers before Fragment Header.
   * And finally adjust by Fragment Header length. */
  len = lwip_ntohs(ip6_current_header()->_plen);
  len -= (u16_t)(((u8_t*)p->payload - (const u8_t*)ip6_current_header()) - IP6_HLEN);
  len -= IP6_FRAG_HLEN;

  /* Look for the datagram the fragment belongs to in the current datagram queue,
   * remembering the previous in the queue for later dequeueing. */
  for (ipr = reassdatagrams, ipr_prev = NULL; ipr != NULL; ipr = ipr->next) {
    /* Check if the incoming fragment matches the one currently present
       in the reassembly buffer. If so, we proceed with copying the
       fragment into the buffer. */
    if ((frag_hdr->_identification == ipr->identification) &&
        ip6_addr_cmp(ip6_current_src_addr(), &(IPV6_FRAG_HDRREF(ipr->iphdr)->src)) &&
        ip6_addr_cmp(ip6_current_dest_addr(), &(IPV6_FRAG_HDRREF(ipr->iphdr)->dest))) {
      IP6_FRAG_STATS_INC(ip6_frag.cachehit);
      break;
    }
    ipr_prev = ipr;
  }

  if (ipr == NULL) {
  /* Enqueue a new datagram into the datagram queue */
    ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
    if (ipr == NULL) {
#if IP_REASS_FREE_OLDEST
      /* Make room and try again. */
      ip6_reass_remove_oldest_datagram(ipr, clen);
      ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
      if (ipr != NULL) {
        /* re-search ipr_prev since it might have been removed */
        for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
          if (ipr_prev->next == ipr) {
            break;
          }
        }
      } else
#endif /* IP_REASS_FREE_OLDEST */
      {
        IP6_FRAG_STATS_INC(ip6_frag.memerr);
        IP6_FRAG_STATS_INC(ip6_frag.drop);
        goto nullreturn;
      }
    }

    memset(ipr, 0, sizeof(struct ip6_reassdata));
    ipr->timer = IP_REASS_MAXAGE;

    /* enqueue the new structure to the front of the list */
    ipr->next = reassdatagrams;
    reassdatagrams = ipr;

    /* Use the current IPv6 header for src/dest address reference.
     * Eventually, we will replace it when we get the first fragment
     * (it might be this one, in any case, it is done later). */
#if IPV6_FRAG_COPYHEADER
    MEMCPY(&ipr->iphdr, ip6_current_header(), IP6_HLEN);
#else /* IPV6_FRAG_COPYHEADER */
    /* need to use the none-const pointer here: */
    ipr->iphdr = ip_data.current_ip6_header;
#endif /* IPV6_FRAG_COPYHEADER */

    /* copy the fragmented packet id. */
    ipr->identification = frag_hdr->_identification;

    /* copy the nexth field */
    ipr->nexth = frag_hdr->_nexth;
  }

  /* Check if we are allowed to enqueue more datagrams. */
  if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
#if IP_REASS_FREE_OLDEST
    ip6_reass_remove_oldest_datagram(ipr, clen);
    if ((ip6_reass_pbufcount + clen) <= IP_REASS_MAX_PBUFS) {
      /* re-search ipr_prev since it might have been removed */
      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
        if (ipr_prev->next == ipr) {
          break;
        }
      }
    } else
#endif /* IP_REASS_FREE_OLDEST */
    {
      /* @todo: send ICMPv6 time exceeded here? */
      /* drop this pbuf */
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
    }
  }

  /* Overwrite Fragment Header with our own helper struct. */
#if IPV6_FRAG_COPYHEADER
  if (IPV6_FRAG_REQROOM > 0) {
    /* Make room for struct ip6_reass_helper (only required if sizeof(void*) > 4).
       This cannot fail since we already checked when receiving this fragment. */
    u8_t hdrerr = pbuf_header_force(p, IPV6_FRAG_REQROOM);
    LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
    LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
  }
#else /* IPV6_FRAG_COPYHEADER */
  LWIP_ASSERT("sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN, set IPV6_FRAG_COPYHEADER to 1",
    sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN);
#endif /* IPV6_FRAG_COPYHEADER */
  iprh = (struct ip6_reass_helper *)p->payload;
  iprh->next_pbuf = NULL;
  iprh->start = (offset & IP6_FRAG_OFFSET_MASK);
  iprh->end = (offset & IP6_FRAG_OFFSET_MASK) + len;

  /* find the right place to insert this pbuf */
  /* Iterate through until we either get to the end of the list (append),
   * or we find on with a larger offset (insert). */
  for (q = ipr->p; q != NULL;) {
    iprh_tmp = (struct ip6_reass_helper*)q->payload;
    if (iprh->start < iprh_tmp->start) {
#if IP_REASS_CHECK_OVERLAP
      if (iprh->end > iprh_tmp->start) {
        /* fragment overlaps with following, throw away */
        IP6_FRAG_STATS_INC(ip6_frag.proterr);
        IP6_FRAG_STATS_INC(ip6_frag.drop);
        goto nullreturn;
      }
      if (iprh_prev != NULL) {
        if (iprh->start < iprh_prev->end) {
          /* fragment overlaps with previous, throw away */
          IP6_FRAG_STATS_INC(ip6_frag.proterr);
          IP6_FRAG_STATS_INC(ip6_frag.drop);
          goto nullreturn;
        }
      }
#endif /* IP_REASS_CHECK_OVERLAP */
      /* the new pbuf should be inserted before this */
      iprh->next_pbuf = q;
      if (iprh_prev != NULL) {
        /* not the fragment with the lowest offset */
        iprh_prev->next_pbuf = p;
      } else {
        /* fragment with the lowest offset */
        ipr->p = p;
      }
      break;
    } else if (iprh->start == iprh_tmp->start) {
      /* received the same datagram twice: no need to keep the datagram */
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
#if IP_REASS_CHECK_OVERLAP
    } else if (iprh->start < iprh_tmp->end) {
      /* overlap: no need to keep the new datagram */
      IP6_FRAG_STATS_INC(ip6_frag.proterr);
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
#endif /* IP_REASS_CHECK_OVERLAP */
    } else {
      /* Check if the fragments received so far have no gaps. */
      if (iprh_prev != NULL) {
        if (iprh_prev->end != iprh_tmp->start) {
          /* There is a fragment missing between the current
           * and the previous fragment */
          valid = 0;
        }
      }
    }
    q = iprh_tmp->next_pbuf;
    iprh_prev = iprh_tmp;
  }

  /* If q is NULL, then we made it to the end of the list. Determine what to do now */
  if (q == NULL) {
    if (iprh_prev != NULL) {
      /* this is (for now), the fragment with the highest offset:
       * chain it to the last fragment */
#if IP_REASS_CHECK_OVERLAP
      LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
#endif /* IP_REASS_CHECK_OVERLAP */
      iprh_prev->next_pbuf = p;
      if (iprh_prev->end != iprh->start) {
        valid = 0;
      }
    } else {
#if IP_REASS_CHECK_OVERLAP
      LWIP_ASSERT("no previous fragment, this must be the first fragment!",
        ipr->p == NULL);
#endif /* IP_REASS_CHECK_OVERLAP */
      /* this is the first fragment we ever received for this ip datagram */
      ipr->p = p;
    }
  }

  /* Track the current number of pbufs current 'in-flight', in order to limit
  the number of fragments that may be enqueued at any one time */
  ip6_reass_pbufcount += clen;

  /* Remember IPv6 header if this is the first fragment. */
  if (iprh->start == 0) {
#if IPV6_FRAG_COPYHEADER
    if (iprh->next_pbuf != NULL) {
      MEMCPY(&ipr->iphdr, ip6_current_header(), IP6_HLEN);
    }
#else /* IPV6_FRAG_COPYHEADER */
    /* need to use the none-const pointer here: */
    ipr->iphdr = ip_data.current_ip6_header;
#endif /* IPV6_FRAG_COPYHEADER */
  }

  /* If this is the last fragment, calculate total packet length. */
  if ((offset & IP6_FRAG_MORE_FLAG) == 0) {
    ipr->datagram_len = iprh->end;
  }

  /* Additional validity tests: we have received first and last fragment. */
  iprh_tmp = (struct ip6_reass_helper*)ipr->p->payload;
  if (iprh_tmp->start != 0) {
    valid = 0;
  }
  if (ipr->datagram_len == 0) {
    valid = 0;
  }

  /* Final validity test: no gaps between current and last fragment. */
  iprh_prev = iprh;
  q = iprh->next_pbuf;
  while ((q != NULL) && valid) {
    iprh = (struct ip6_reass_helper*)q->payload;
    if (iprh_prev->end != iprh->start) {
      valid = 0;
      break;
    }
    iprh_prev = iprh;
    q = iprh->next_pbuf;
  }

  if (valid) {
    /* All fragments have been received */
    struct ip6_hdr* iphdr_ptr;

    /* chain together the pbufs contained within the ip6_reassdata list. */
    iprh = (struct ip6_reass_helper*) ipr->p->payload;
    while (iprh != NULL) {
      struct pbuf* next_pbuf = iprh->next_pbuf;
      if (next_pbuf != NULL) {
        /* Save next helper struct (will be hidden in next step). */
        iprh_tmp = (struct ip6_reass_helper*)next_pbuf->payload;

        /* hide the fragment header for every succeeding fragment */
        pbuf_header(next_pbuf, -IP6_FRAG_HLEN);
#if IPV6_FRAG_COPYHEADER
        if (IPV6_FRAG_REQROOM > 0) {
          /* hide the extra bytes borrowed from ip6_hdr for struct ip6_reass_helper */
          u8_t hdrerr = pbuf_header(next_pbuf, -(s16_t)(IPV6_FRAG_REQROOM));
          LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
          LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
        }
#endif
        pbuf_cat(ipr->p, next_pbuf);
      }
      else {
        iprh_tmp = NULL;
      }

      iprh = iprh_tmp;
    }

#if IPV6_FRAG_COPYHEADER
    if (IPV6_FRAG_REQROOM > 0) {
      /* get back room for struct ip6_reass_helper (only required if sizeof(void*) > 4) */
      u8_t hdrerr = pbuf_header(ipr->p, -(s16_t)(IPV6_FRAG_REQROOM));
      LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
      LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
    }
    iphdr_ptr = (struct ip6_hdr*)((u8_t*)ipr->p->payload - IP6_HLEN);
    MEMCPY(iphdr_ptr, &ipr->iphdr, IP6_HLEN);
#else
    iphdr_ptr = ipr->iphdr;
#endif

    /* Adjust datagram length by adding header lengths. */
    ipr->datagram_len += (u16_t)(((u8_t*)ipr->p->payload - (u8_t*)iphdr_ptr)
                         + IP6_FRAG_HLEN
                         - IP6_HLEN);

    /* Set payload length in ip header. */
    iphdr_ptr->_plen = lwip_htons(ipr->datagram_len);

    /* Get the first pbuf. */
    p = ipr->p;

    /* Restore Fragment Header in first pbuf. Mark as "single fragment"
     * packet. Restore nexth. */
    frag_hdr = (struct ip6_frag_hdr *) p->payload;
    frag_hdr->_nexth = ipr->nexth;
    frag_hdr->reserved = 0;
    frag_hdr->_fragment_offset = 0;
    frag_hdr->_identification = 0;

    /* release the sources allocate for the fragment queue entry */
    if (reassdatagrams == ipr) {
      /* it was the first in the list */
      reassdatagrams = ipr->next;
    } else {
      /* it wasn't the first, so it must have a valid 'prev' */
      LWIP_ASSERT("sanity check linked list", ipr_prev != NULL);
      ipr_prev->next = ipr->next;
    }
    memp_free(MEMP_IP6_REASSDATA, ipr);

    /* adjust the number of pbufs currently queued for reassembly. */
    ip6_reass_pbufcount -= pbuf_clen(p);

    /* Move pbuf back to IPv6 header.
       This cannot fail since we already checked when receiving this fragment. */
    if (pbuf_header_force(p, (s16_t)((u8_t*)p->payload - (u8_t*)iphdr_ptr))) {
      LWIP_ASSERT("ip6_reass: moving p->payload to ip6 header failed\n", 0);
      pbuf_free(p);
      return NULL;
    }

    /* Return the pbuf chain */
    return p;
  }
  /* the datagram is not (yet?) reassembled completely */
  return NULL;

nullreturn:
  pbuf_free(p);
  return NULL;
}
Exemple #19
0
/**
 * Reassembles incoming IP fragments into an IP datagram.
 *
 * @param p points to a pbuf chain of the fragment
 * @return NULL if reassembly is incomplete, ? otherwise
 */
struct pbuf *
ip_reass(struct pbuf *p)
{
  struct pbuf *r;
  struct ip_hdr *fraghdr;
  struct ip_reassdata *ipr;
  struct ip_reass_helper *iprh;
  u16_t offset, len;
  u8_t clen;
  struct ip_reassdata *ipr_prev = NULL;

  IPFRAG_STATS_INC(ip_frag.recv);
  snmp_inc_ipreasmreqds();

  fraghdr = (struct ip_hdr*)p->payload;

  if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
    LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
    IPFRAG_STATS_INC(ip_frag.err);
    goto nullreturn;
  }

  offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
  len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;

  /* Check if we are allowed to enqueue more datagrams. */
  clen = pbuf_clen(p);
  if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
#if IP_REASS_FREE_OLDEST
    if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
        ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
#endif /* IP_REASS_FREE_OLDEST */
    {
      /* No datagram could be freed and still too many pbufs enqueued */
      LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
        ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
      IPFRAG_STATS_INC(ip_frag.memerr);
      /* @todo: send ICMP time exceeded here? */
      /* drop this pbuf */
      goto nullreturn;
    }
  }

  /* Look for the datagram the fragment belongs to in the current datagram queue,
   * remembering the previous in the queue for later dequeueing. */
  for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
    /* Check if the incoming fragment matches the one currently present
       in the reassembly buffer. If so, we proceed with copying the
       fragment into the buffer. */
    if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
        ntohs(IPH_ID(fraghdr))));
      IPFRAG_STATS_INC(ip_frag.cachehit);
      break;
    }
    ipr_prev = ipr;
  }

  if (ipr == NULL) {
  /* Enqueue a new datagram into the datagram queue */
    ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
    /* Bail if unable to enqueue */
    if(ipr == NULL) {
      goto nullreturn;
    }
  } else {
    if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) && 
      ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
      /* ipr->iphdr is not the header from the first fragment, but fraghdr is
       * -> copy fraghdr into ipr->iphdr since we want to have the header
       * of the first fragment (for ICMP time exceeded and later, for copying
       * all options, if supported)*/
      SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
    }
  }
  /* Track the current number of pbufs current 'in-flight', in order to limit 
  the number of fragments that may be enqueued at any one time */
  ip_reass_pbufcount += clen;

  /* At this point, we have either created a new entry or pointing 
   * to an existing one */

  /* check for 'no more fragments', and update queue entry*/
  if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
    ipr->flags |= IP_REASS_FLAG_LASTFRAG;
    ipr->datagram_len = offset + len;
    LWIP_DEBUGF(IP_REASS_DEBUG,
     ("ip_reass: last fragment seen, total len %"S16_F"\n",
      ipr->datagram_len));
  }
  /* find the right place to insert this pbuf */
  /* @todo: trim pbufs if fragments are overlapping */
  if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
    /* the totally last fragment (flag more fragments = 0) was received at least
     * once AND all fragments are received */
    ipr->datagram_len += IP_HLEN;

    /* save the second pbuf before copying the header over the pointer */
    r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;

    /* copy the original ip header back to the first pbuf */
    fraghdr = (struct ip_hdr*)(ipr->p->payload);
    SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
    IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
    IPH_OFFSET_SET(fraghdr, 0);
    IPH_CHKSUM_SET(fraghdr, 0);
    /* @todo: do we need to set calculate the correct checksum? */
    IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));

    p = ipr->p;

    /* chain together the pbufs contained within the reass_data list. */
    while(r != NULL) {
      iprh = (struct ip_reass_helper*)r->payload;

      /* hide the ip header for every succeding fragment */
      pbuf_header(r, -IP_HLEN);
      pbuf_cat(p, r);
      r = iprh->next_pbuf;
    }
    /* release the sources allocate for the fragment queue entry */
    ip_reass_dequeue_datagram(ipr, ipr_prev);

    /* and adjust the number of pbufs currently queued for reassembly. */
    ip_reass_pbufcount -= pbuf_clen(p);

    /* Return the pbuf chain */
    return p;
  }
  /* the datagram is not (yet?) reassembled completely */
  LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
  return NULL;

nullreturn:
  LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
  IPFRAG_STATS_INC(ip_frag.drop);
  pbuf_free(p);
  return NULL;
}
/** State machine-like implementation of an SMTP client.
 */
static void
smtp_process(void *arg, struct tcp_pcb *pcb, struct pbuf *p)
{
  struct smtp_session* s = arg;
  u16_t response_code = 0;
  u16_t tx_buf_len = 0;
  enum smtp_session_state next_state;

  if (arg == NULL) {
    /* already closed SMTP connection */
    if (p != NULL) {
      LWIP_DEBUGF(SMTP_DEBUG_TRACE, ("Received %d bytes after closing: %s\n",
        p->tot_len, smtp_pbuf_str(p)));
      pbuf_free(p);
    }
    return;
  }

  next_state = s->state;

  if (p != NULL) {
    /* received data */
    if (s->p == NULL) {
      s->p = p;
    } else {
      pbuf_cat(s->p, p);
    }
  } else {
    /* idle timer, close connection if timed out */
    if (s->timer == 0) {
      LWIP_DEBUGF(SMTP_DEBUG_WARN_STATE, ("smtp_process: connection timed out, closing\n"));
      smtp_close(s, pcb, SMTP_RESULT_ERR_TIMEOUT, 0, ERR_TIMEOUT);
      return;
    }
    if (s->state == SMTP_BODY) {
      smtp_send_body(s, pcb);
      return;
    }
  }
  response_code = smtp_is_response(s);
  if (response_code) {
    LWIP_DEBUGF(SMTP_DEBUG_TRACE, ("smtp_process: received response code: %d\n", response_code));
    if (smtp_is_response_finished(s) != ERR_OK) {
      LWIP_DEBUGF(SMTP_DEBUG_TRACE, ("smtp_process: partly received response code: %d\n", response_code));
      /* wait for next packet to complete the respone */
      return;
    }
  } else {
    if (s->p != NULL) {
      LWIP_DEBUGF(SMTP_DEBUG_WARN, ("smtp_process: unknown data received (%s)\n",
        smtp_pbuf_str(s->p)));
      pbuf_free(s->p);
      s->p = NULL;
    }
    return;
  }

  switch(s->state)
  {
  case(SMTP_NULL):
    /* wait for 220 */
    if (response_code == 220) {
      /* then send EHLO */
      next_state = smtp_prepare_helo(s, &tx_buf_len, pcb);
    }
    break;
  case(SMTP_HELO):
    /* wait for 250 */
    if (response_code == 250) {
#if SMTP_SUPPORT_AUTH_AUTH || SMTP_SUPPORT_AUTH_LOGIN
      /* then send AUTH or MAIL */
      next_state = smtp_prepare_auth_or_mail(s, &tx_buf_len);
    }
    break;
  case(SMTP_AUTH_LOGIN):
  case(SMTP_AUTH_PLAIN):
    /* wait for 235 */
    if (response_code == 235) {
#endif /* SMTP_SUPPORT_AUTH_AUTH || SMTP_SUPPORT_AUTH_LOGIN */
      /* send MAIL */
      next_state = smtp_prepare_mail(s, &tx_buf_len);
    }
    break;
#if SMTP_SUPPORT_AUTH_LOGIN
  case(SMTP_AUTH_LOGIN_UNAME):
    /* wait for 334 Username */
    if (response_code == 334) {
      if (pbuf_strstr(s->p, SMTP_RESP_LOGIN_UNAME) != 0xFFFF) {
        /* send username */
        next_state = smtp_prepare_auth_login_uname(s, &tx_buf_len);
      }
    }
    break;
  case(SMTP_AUTH_LOGIN_PASS):
    /* wait for 334 Password */
    if (response_code == 334) {
      if (pbuf_strstr(s->p, SMTP_RESP_LOGIN_PASS) != 0xFFFF) {
        /* send username */
        next_state = smtp_prepare_auth_login_pass(s, &tx_buf_len);
      }
    }
    break;
#endif /* SMTP_SUPPORT_AUTH_LOGIN */
  case(SMTP_MAIL):
    /* wait for 250 */
    if (response_code == 250) {
      /* send RCPT */
      next_state = smtp_prepare_rcpt(s, &tx_buf_len);
    }
    break;
  case(SMTP_RCPT):
    /* wait for 250 */
    if (response_code == 250) {
      /* send DATA */
      SMEMCPY(s->tx_buf, SMTP_CMD_DATA, SMTP_CMD_DATA_LEN);
      tx_buf_len = SMTP_CMD_DATA_LEN;
      next_state = SMTP_DATA;
    }
    break;
  case(SMTP_DATA):
    /* wait for 354 */
    if (response_code == 354) {
      /* send email header */
      next_state = smtp_prepare_header(s, &tx_buf_len);
    }
    break;
  case(SMTP_BODY):
    /* nothing to be done here, handled somewhere else */
    break;
  case(SMTP_QUIT):
    /* wait for 250 */
    if (response_code == 250) {
      /* send QUIT */
      next_state = smtp_prepare_quit(s, &tx_buf_len);
    }
    break;
  case(SMTP_CLOSED):
    /* nothing to do, wait for connection closed from server */
    return;
  default:
    LWIP_DEBUGF(SMTP_DEBUG_SERIOUS, ("Invalid state: %d/%s\n", (int)s->state,
      smtp_state_str[s->state]));
    break;
  }
  if (s->state == next_state) {
    LWIP_DEBUGF(SMTP_DEBUG_WARN_STATE, ("smtp_process[%s]: unexpected response_code, closing: %d (%s)\n",
      smtp_state_str[s->state], response_code, smtp_pbuf_str(s->p)));
    /* close connection */
    smtp_close(s, pcb, SMTP_RESULT_ERR_SVR_RESP, response_code, ERR_OK);
    return;
  }
  if (tx_buf_len > 0) {
    SMTP_TX_BUF_MAX(tx_buf_len);
    if (tcp_write(pcb, s->tx_buf, tx_buf_len, TCP_WRITE_FLAG_COPY) == ERR_OK) {
      LWIP_DEBUGF(SMTP_DEBUG_TRACE, ("smtp_process[%s]: received command %d (%s)\n",
        smtp_state_str[s->state], response_code, smtp_pbuf_str(s->p)));
      LWIP_DEBUGF(SMTP_DEBUG_TRACE, ("smtp_process[%s]: sent %"U16_F" bytes: \"%s\"\n",
        smtp_state_str[s->state], tx_buf_len, s->tx_buf));
      s->timer = SMTP_TIMEOUT;
      pbuf_free(s->p);
      s->p = NULL;
      LWIP_DEBUGF(SMTP_DEBUG_STATE, ("smtp_process: changing state from %s to %s\n",
        smtp_state_str[s->state], smtp_state_str[next_state]));
      s->state = next_state;
      if (next_state == SMTP_BODY) {
        /* try to stream-send body data right now */
        smtp_send_body(s, pcb);
      } else if (next_state == SMTP_CLOSED) {
        /* sent out all data, delete structure */
        tcp_arg(pcb, NULL);
        smtp_free(s, SMTP_RESULT_OK, 0, ERR_OK);
      }
    }
  }
}
Exemple #21
0
/**
 * Handle the incoming SLIP stream character by character
 *
 * Poll the serial layer by calling sio_recv()
 *
 * @param netif the lwip network interface structure for this slipif
 * @param block if 1, block until data is received; if 0, return when all data
 *        from the buffer is received (multiple calls to this function will
 *        return a complete packet, NULL is returned before - used for polling)
 * @return The IP packet when SLIP_END is received
 */
static struct pbuf *
slipif_input(struct netif *netif, u8_t block)
{
  struct slipif_priv *priv;
  u8_t c;
  struct pbuf *t;

  LWIP_ASSERT("netif != NULL", (netif != NULL));
  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));

  priv = netif->state;

  while (slip_sio_read(priv->sd, &c, 1, block) > 0) {
    switch (priv->state) {
    case SLIP_RECV_NORMAL:
      switch (c) {
      case SLIP_END:
        if (priv->recved > 0) {
          /* Received whole packet. */
          /* Trim the pbuf to the size of the received packet. */
          pbuf_realloc(priv->q, priv->recved);

          LINK_STATS_INC(link.recv);

          LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
          t = priv->q;
          priv->p = priv->q = NULL;
          priv->i = priv->recved = 0;
          return t;
        }
        continue;
      case SLIP_ESC:
        priv->state = SLIP_RECV_ESCAPE;
        continue;
      }
      break;
    case SLIP_RECV_ESCAPE:
      switch (c) {
      case SLIP_ESC_END:
        c = SLIP_END;
        break;
      case SLIP_ESC_ESC:
        c = SLIP_ESC;
        break;
      }
      priv->state = SLIP_RECV_NORMAL;
      /* FALLTHROUGH */
    }

    /* byte received, packet not yet completely received */
    if (priv->p == NULL) {
      /* allocate a new pbuf */
      LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
      priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);

      if (priv->p == NULL) {
        LINK_STATS_INC(link.drop);
        LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
        /* don't process any further since we got no pbuf to receive to */
        break;
      }

      if (priv->q != NULL) {
        /* 'chain' the pbuf to the existing chain */
        pbuf_cat(priv->q, priv->p);
      } else {
        /* p is the first pbuf in the chain */
        priv->q = priv->p;
      }
    }

    /* this automatically drops bytes if > SLIP_MAX_SIZE */
    if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
      ((u8_t *)priv->p->payload)[priv->i] = c;
      priv->recved++;
      priv->i++;
      if (priv->i >= priv->p->len) {
        /* on to the next pbuf */
        priv->i = 0;
        if (priv->p->next != NULL && priv->p->next->len > 0) {
          /* p is a chain, on to the next in the chain */
            priv->p = priv->p->next;
        } else {
          /* p is a single pbuf, set it to NULL so next time a new
           * pbuf is allocated */
            priv->p = NULL;
        }
      }
    }
  }

  return NULL;
}
Exemple #22
0
/**
 * Reassembles incoming IPv6 fragments into an IPv6 datagram.
 *
 * @param p points to the IPv6 Fragment Header
 * @return NULL if reassembly is incomplete, pbuf pointing to
 *         IPv6 Header if reassembly is complete
 */
struct pbuf *
ip6_reass(struct pbuf *p)
{
  struct ip6_reassdata *ipr, *ipr_prev;
  struct ip6_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
  struct ip6_frag_hdr *frag_hdr;
  u16_t offset, len, start, end;
  ptrdiff_t hdrdiff;
  u16_t clen;
  u8_t valid = 1;
  struct pbuf *q, *next_pbuf;

  IP6_FRAG_STATS_INC(ip6_frag.recv);

  /* ip6_frag_hdr must be in the first pbuf, not chained. Checked by caller. */
  LWIP_ASSERT("IPv6 fragment header does not fit in first pbuf",
    p->len >= sizeof(struct ip6_frag_hdr));

  frag_hdr = (struct ip6_frag_hdr *) p->payload;

  clen = pbuf_clen(p);

  offset = lwip_ntohs(frag_hdr->_fragment_offset);

  /* Calculate fragment length from IPv6 payload length.
   * Adjust for headers before Fragment Header.
   * And finally adjust by Fragment Header length. */
  len = lwip_ntohs(ip6_current_header()->_plen);
  hdrdiff = (u8_t*)p->payload - (const u8_t*)ip6_current_header();
  LWIP_ASSERT("not a valid pbuf (ip6_input check missing?)", hdrdiff <= 0xFFFF);
  LWIP_ASSERT("not a valid pbuf (ip6_input check missing?)", hdrdiff >= IP6_HLEN);
  hdrdiff -= IP6_HLEN;
  hdrdiff += IP6_FRAG_HLEN;
  if (hdrdiff > len) {
    IP6_FRAG_STATS_INC(ip6_frag.proterr);
    goto nullreturn;
  }
  len = (u16_t)(len - hdrdiff);
  start = (offset & IP6_FRAG_OFFSET_MASK);
  if (start > (0xFFFF - len)) {
    /* u16_t overflow, cannot handle this */
    IP6_FRAG_STATS_INC(ip6_frag.proterr);
    goto nullreturn;
  }

  /* Look for the datagram the fragment belongs to in the current datagram queue,
   * remembering the previous in the queue for later dequeueing. */
  for (ipr = reassdatagrams, ipr_prev = NULL; ipr != NULL; ipr = ipr->next) {
    /* Check if the incoming fragment matches the one currently present
       in the reassembly buffer. If so, we proceed with copying the
       fragment into the buffer. */
    if ((frag_hdr->_identification == ipr->identification) &&
        ip6_addr_cmp_packed(ip6_current_src_addr(), &(IPV6_FRAG_SRC(ipr)), ipr->src_zone) &&
        ip6_addr_cmp_packed(ip6_current_dest_addr(), &(IPV6_FRAG_DEST(ipr)), ipr->dest_zone)) {
      IP6_FRAG_STATS_INC(ip6_frag.cachehit);
      break;
    }
    ipr_prev = ipr;
  }

  if (ipr == NULL) {
  /* Enqueue a new datagram into the datagram queue */
    ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
    if (ipr == NULL) {
#if IP_REASS_FREE_OLDEST
      /* Make room and try again. */
      ip6_reass_remove_oldest_datagram(ipr, clen);
      ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
      if (ipr != NULL) {
        /* re-search ipr_prev since it might have been removed */
        for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
          if (ipr_prev->next == ipr) {
            break;
          }
        }
      } else
#endif /* IP_REASS_FREE_OLDEST */
      {
        IP6_FRAG_STATS_INC(ip6_frag.memerr);
        goto nullreturn;
      }
    }

    memset(ipr, 0, sizeof(struct ip6_reassdata));
    ipr->timer = IPV6_REASS_MAXAGE;

    /* enqueue the new structure to the front of the list */
    ipr->next = reassdatagrams;
    reassdatagrams = ipr;

    /* Use the current IPv6 header for src/dest address reference.
     * Eventually, we will replace it when we get the first fragment
     * (it might be this one, in any case, it is done later). */
    /* need to use the none-const pointer here: */
    ipr->iphdr = ip_data.current_ip6_header;
#if IPV6_FRAG_COPYHEADER
    MEMCPY(&ipr->src, &ip6_current_header()->src, sizeof(ipr->src));
    MEMCPY(&ipr->dest, &ip6_current_header()->dest, sizeof(ipr->dest));
#endif /* IPV6_FRAG_COPYHEADER */
#if LWIP_IPV6_SCOPES
    /* Also store the address zone information.
     * @todo It is possible that due to netif destruction and recreation, the
     * stored zones end up resolving to a different interface. In that case, we
     * risk sending a "time exceeded" ICMP response over the wrong link.
     * Ideally, netif destruction would clean up matching pending reassembly
     * structures, but custom zone mappings would make that non-trivial. */
    ipr->src_zone = ip6_addr_zone(ip6_current_src_addr());
    ipr->dest_zone = ip6_addr_zone(ip6_current_dest_addr());
#endif /* LWIP_IPV6_SCOPES */
    /* copy the fragmented packet id. */
    ipr->identification = frag_hdr->_identification;

    /* copy the nexth field */
    ipr->nexth = frag_hdr->_nexth;
  }

  /* Check if we are allowed to enqueue more datagrams. */
  if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
#if IP_REASS_FREE_OLDEST
    ip6_reass_remove_oldest_datagram(ipr, clen);
    if ((ip6_reass_pbufcount + clen) <= IP_REASS_MAX_PBUFS) {
      /* re-search ipr_prev since it might have been removed */
      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
        if (ipr_prev->next == ipr) {
          break;
        }
      }
    } else
#endif /* IP_REASS_FREE_OLDEST */
    {
      /* @todo: send ICMPv6 time exceeded here? */
      /* drop this pbuf */
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      goto nullreturn;
    }
  }

  /* Overwrite Fragment Header with our own helper struct. */
#if IPV6_FRAG_COPYHEADER
  if (IPV6_FRAG_REQROOM > 0) {
    /* Make room for struct ip6_reass_helper (only required if sizeof(void*) > 4).
       This cannot fail since we already checked when receiving this fragment. */
    u8_t hdrerr = pbuf_header_force(p, IPV6_FRAG_REQROOM);
    LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
    LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
  }
#else /* IPV6_FRAG_COPYHEADER */
  LWIP_ASSERT("sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN, set IPV6_FRAG_COPYHEADER to 1",
    sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN);
#endif /* IPV6_FRAG_COPYHEADER */

  /* Prepare the pointer to the helper structure, and its initial values.
   * Do not yet write to the structure itself, as we still have to make a
   * backup of the original data, and we should not do that until we know for
   * sure that we are going to add this packet to the list. */
  iprh = (struct ip6_reass_helper *)p->payload;
  next_pbuf = NULL;
  end = (u16_t)(start + len);

  /* find the right place to insert this pbuf */
  /* Iterate through until we either get to the end of the list (append),
   * or we find on with a larger offset (insert). */
  for (q = ipr->p; q != NULL;) {
    iprh_tmp = (struct ip6_reass_helper*)q->payload;
    if (start < iprh_tmp->start) {
#if IP_REASS_CHECK_OVERLAP
      if (end > iprh_tmp->start) {
        /* fragment overlaps with following, throw away */
        IP6_FRAG_STATS_INC(ip6_frag.proterr);
        goto nullreturn;
      }
      if (iprh_prev != NULL) {
        if (start < iprh_prev->end) {
          /* fragment overlaps with previous, throw away */
          IP6_FRAG_STATS_INC(ip6_frag.proterr);
          goto nullreturn;
        }
      }
#endif /* IP_REASS_CHECK_OVERLAP */
      /* the new pbuf should be inserted before this */
      next_pbuf = q;
      if (iprh_prev != NULL) {
        /* not the fragment with the lowest offset */
        iprh_prev->next_pbuf = p;
      } else {
        /* fragment with the lowest offset */
        ipr->p = p;
      }
      break;
    } else if (start == iprh_tmp->start) {
      /* received the same datagram twice: no need to keep the datagram */
      goto nullreturn;
#if IP_REASS_CHECK_OVERLAP
    } else if (start < iprh_tmp->end) {
      /* overlap: no need to keep the new datagram */
      IP6_FRAG_STATS_INC(ip6_frag.proterr);
      goto nullreturn;
#endif /* IP_REASS_CHECK_OVERLAP */
    } else {
      /* Check if the fragments received so far have no gaps. */
      if (iprh_prev != NULL) {
        if (iprh_prev->end != iprh_tmp->start) {
          /* There is a fragment missing between the current
           * and the previous fragment */
          valid = 0;
        }
      }
    }
    q = iprh_tmp->next_pbuf;
    iprh_prev = iprh_tmp;
  }

  /* If q is NULL, then we made it to the end of the list. Determine what to do now */
  if (q == NULL) {
    if (iprh_prev != NULL) {
      /* this is (for now), the fragment with the highest offset:
       * chain it to the last fragment */
#if IP_REASS_CHECK_OVERLAP
      LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= start);
#endif /* IP_REASS_CHECK_OVERLAP */
      iprh_prev->next_pbuf = p;
      if (iprh_prev->end != start) {
        valid = 0;
      }
    } else {
#if IP_REASS_CHECK_OVERLAP
      LWIP_ASSERT("no previous fragment, this must be the first fragment!",
        ipr->p == NULL);
#endif /* IP_REASS_CHECK_OVERLAP */
      /* this is the first fragment we ever received for this ip datagram */
      ipr->p = p;
    }
  }

  /* Track the current number of pbufs current 'in-flight', in order to limit
  the number of fragments that may be enqueued at any one time */
  ip6_reass_pbufcount = (u16_t)(ip6_reass_pbufcount + clen);

  /* Remember IPv6 header if this is the first fragment. */
  if (start == 0) {
    /* need to use the none-const pointer here: */
    ipr->iphdr = ip_data.current_ip6_header;
    /* Make a backup of the part of the packet data that we are about to
     * overwrite, so that we can restore the original later. */
    MEMCPY(ipr->orig_hdr, p->payload, sizeof(*iprh));
    /* For IPV6_FRAG_COPYHEADER there is no need to copy src/dst again, as they
     * will be the same as they were. With LWIP_IPV6_SCOPES, the same applies
     * to the source/destination zones. */
  }
  /* Only after the backup do we get to fill in the actual helper structure. */
  iprh->next_pbuf = next_pbuf;
  iprh->start = start;
  iprh->end = end;

  /* If this is the last fragment, calculate total packet length. */
  if ((offset & IP6_FRAG_MORE_FLAG) == 0) {
    ipr->datagram_len = iprh->end;
  }

  /* Additional validity tests: we have received first and last fragment. */
  iprh_tmp = (struct ip6_reass_helper*)ipr->p->payload;
  if (iprh_tmp->start != 0) {
    valid = 0;
  }
  if (ipr->datagram_len == 0) {
    valid = 0;
  }

  /* Final validity test: no gaps between current and last fragment. */
  iprh_prev = iprh;
  q = iprh->next_pbuf;
  while ((q != NULL) && valid) {
    iprh = (struct ip6_reass_helper*)q->payload;
    if (iprh_prev->end != iprh->start) {
      valid = 0;
      break;
    }
    iprh_prev = iprh;
    q = iprh->next_pbuf;
  }

  if (valid) {
    /* All fragments have been received */
    struct ip6_hdr* iphdr_ptr;

    /* chain together the pbufs contained within the ip6_reassdata list. */
    iprh = (struct ip6_reass_helper*) ipr->p->payload;
    while (iprh != NULL) {
      next_pbuf = iprh->next_pbuf;
      if (next_pbuf != NULL) {
        /* Save next helper struct (will be hidden in next step). */
        iprh_tmp = (struct ip6_reass_helper*)next_pbuf->payload;

        /* hide the fragment header for every succeeding fragment */
        pbuf_remove_header(next_pbuf, IP6_FRAG_HLEN);
#if IPV6_FRAG_COPYHEADER
        if (IPV6_FRAG_REQROOM > 0) {
          /* hide the extra bytes borrowed from ip6_hdr for struct ip6_reass_helper */
          u8_t hdrerr = pbuf_remove_header(next_pbuf, IPV6_FRAG_REQROOM);
          LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
          LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
        }
#endif
        pbuf_cat(ipr->p, next_pbuf);
      }
      else {
        iprh_tmp = NULL;
      }

      iprh = iprh_tmp;
    }

    /* Get the first pbuf. */
    p = ipr->p;

#if IPV6_FRAG_COPYHEADER
    if (IPV6_FRAG_REQROOM > 0) {
      u8_t hdrerr;
      /* Restore (only) the bytes that we overwrote beyond the fragment header.
       * Those bytes may belong to either the IPv6 header or an extension
       * header placed before the fragment header. */
      MEMCPY(p->payload, ipr->orig_hdr, IPV6_FRAG_REQROOM);
      /* get back room for struct ip6_reass_helper (only required if sizeof(void*) > 4) */
      hdrerr = pbuf_remove_header(p, IPV6_FRAG_REQROOM);
      LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
      LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
    }
#endif

    /* We need to get rid of the fragment header itself, which is somewhere in
     * the middle of the packet (but still in the first pbuf of the chain).
     * Getting rid of the header is required by RFC 2460 Sec. 4.5 and necessary
     * in order to be able to reassemble packets that are close to full size
     * (i.e., around 65535 bytes). We simply move up all the headers before the
     * fragment header, including the IPv6 header, and adjust the payload start
     * accordingly. This works because all these headers are in the first pbuf
     * of the chain, and because the caller adjusts all its pointers on
     * successful reassembly. */
    MEMMOVE((u8_t*)ipr->iphdr + sizeof(struct ip6_frag_hdr), ipr->iphdr,
      (size_t)((u8_t*)p->payload - (u8_t*)ipr->iphdr));

    /* This is where the IPv6 header is now. */
    iphdr_ptr = (struct ip6_hdr*)((u8_t*)ipr->iphdr +
      sizeof(struct ip6_frag_hdr));

    /* Adjust datagram length by adding header lengths. */
    ipr->datagram_len = (u16_t)(ipr->datagram_len + ((u8_t*)p->payload - (u8_t*)iphdr_ptr)
                         - IP6_HLEN);

    /* Set payload length in ip header. */
    iphdr_ptr->_plen = lwip_htons(ipr->datagram_len);

    /* With the fragment header gone, we now need to adjust the next-header
     * field of whatever header was originally before it. Since the packet made
     * it through the original header processing routines at least up to the
     * fragment header, we do not need any further sanity checks here. */
    if (IP6H_NEXTH(iphdr_ptr) == IP6_NEXTH_FRAGMENT) {
      iphdr_ptr->_nexth = ipr->nexth;
    } else {
      u8_t *ptr = (u8_t *)iphdr_ptr + IP6_HLEN;
      while (*ptr != IP6_NEXTH_FRAGMENT) {
        ptr += 8 * (1 + ptr[1]);
      }
      *ptr = ipr->nexth;
    }

    /* release the resources allocated for the fragment queue entry */
    if (reassdatagrams == ipr) {
      /* it was the first in the list */
      reassdatagrams = ipr->next;
    } else {
      /* it wasn't the first, so it must have a valid 'prev' */
      LWIP_ASSERT("sanity check linked list", ipr_prev != NULL);
      ipr_prev->next = ipr->next;
    }
    memp_free(MEMP_IP6_REASSDATA, ipr);

    /* adjust the number of pbufs currently queued for reassembly. */
    clen = pbuf_clen(p);
    LWIP_ASSERT("ip6_reass_pbufcount >= clen", ip6_reass_pbufcount >= clen);
    ip6_reass_pbufcount = (u16_t)(ip6_reass_pbufcount - clen);

    /* Move pbuf back to IPv6 header. This should never fail. */
    if (pbuf_header_force(p, (s16_t)((u8_t*)p->payload - (u8_t*)iphdr_ptr))) {
      LWIP_ASSERT("ip6_reass: moving p->payload to ip6 header failed\n", 0);
      pbuf_free(p);
      return NULL;
    }

    /* Return the pbuf chain */
    return p;
  }
  /* the datagram is not (yet?) reassembled completely */
  return NULL;

nullreturn:
  IP6_FRAG_STATS_INC(ip6_frag.drop);
  pbuf_free(p);
  return NULL;
}
err_t tcp_enqueue (
       struct tcp_pcb* pcb, void* arg, u16_t len,
       u8_t          flags, u8_t            copy,
       u8_t*       optdata, u8_t          optlen
      ) {

 struct pbuf*    p;
 struct tcp_seg* seg, *useg, *queue;
 u32_t           left, seqno;
 u16_t           seglen;
 void*           ptr;
 u8_t            queuelen;
 flags_t         lPCBFlags = pcb -> flags;
 int             iSegCNT   = 0;

 left = len;
 ptr  = arg;

 if ( len > pcb -> snd_buf ) return ERR_MEM;

 seqno    = pcb -> snd_lbb;
 queue    = NULL;
 queuelen = pcb -> snd_queuelen;

 if ( queuelen >= TCP_SND_QUEUELEN ) goto memerr;

 seg    = useg = NULL;
 seglen = 0;

 while ( !queue || left > 0 ) {

  if ( lPCBFlags & TF_EVENSEG ) {

   ++iSegCNT;

   seglen = left > pcb -> mss ? pcb -> mss
                              : (((iSegCNT%2) == 1)? ((left + 1) / 2): left);
  } else seglen = left > pcb -> mss ? pcb -> mss : left;

  seg = memp_malloc ( MEMP_TCP_SEG );

  if ( !seg ) goto memerr;

  seg -> next = NULL;
  seg -> p    = NULL;

  if ( !queue )
   useg = queue = seg;
  else {
   useg -> next = seg;
   useg         = seg;
  }  /* end else */

    if (optdata != NULL) {
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
        goto memerr;
      }
      ++queuelen;
      seg->dataptr = seg->p->payload;
    }
    else if (copy) {
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) {
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue : could not allocate memory for pbuf copy size %u\n", seglen));
        goto memerr;
      }
      ++queuelen;
      if (arg != NULL) {
        mips_memcpy(seg->p->payload, ptr, seglen);
      }
      seg->dataptr = seg->p->payload;
    }
    /* do not copy data */
    else {

      /* first, allocate a pbuf for holding the data.
       * since the referenced data is available at least until it is sent out on the
       * link (as it has to be ACKed by the remote party) we can safely use PBUF_ROM
       * instead of PBUF_REF here.
       */
      if ((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for zero-copy pbuf\n"));
        goto memerr;
      }
      ++queuelen;
      p->payload = ptr;
      seg->dataptr = ptr;

      /* Second, allocate a pbuf for the headers. */
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) {
        /* If allocation fails, we have to deallocate the data pbuf as
         * well. */
        pbuf_free(p);
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for header pbuf\n"));
        goto memerr;
      }
      ++queuelen;

      /* Concatenate the headers and data pbufs together. */
      pbuf_cat(seg->p, p);
      p = NULL;
    }

    /* Now that there are more segments queued, we check again if the
    length of the queue exceeds the configured maximum. */
    if (queuelen > TCP_SND_QUEUELEN) {
      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: queue too long %u (%u)\n", queuelen, TCP_SND_QUEUELEN));
      goto memerr;
    }

    seg->len = seglen;

    if (pbuf_header(seg->p, TCP_HLEN)) {

      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: no room for TCP header in pbuf.\n"));

      TCP_STATS_INC(tcp.err);
      goto memerr;
    }
    seg->tcphdr = seg->p->payload;
    seg->tcphdr->src = htons(pcb->local_port);
    seg->tcphdr->dest = htons(pcb->remote_port);
    seg->tcphdr->seqno = htonl(seqno);
    seg->tcphdr->urgp = 0;
    TCPH_FLAGS_SET(seg->tcphdr, flags);
    /* don't fill in tcphdr->ackno and tcphdr->wnd until later */

    /* Copy the options into the header, if they are present. */
    if (optdata == NULL) {
      TCPH_HDRLEN_SET(seg->tcphdr, 5);
    }
    else {
      TCPH_HDRLEN_SET(seg->tcphdr, (5 + optlen / 4));
      /* Copy options into data portion of segment.
       Options can thus only be sent in non data carrying
       segments such as SYN|ACK. */
      mips_memcpy(seg->dataptr, optdata, optlen);
    }

    left -= seglen;
    seqno += seglen;
    ptr = (void *)((char *)ptr + seglen);
  }


  /* Now that the data to be enqueued has been broken up into TCP
  segments in the queue variable, we add them to the end of the
  pcb->unsent queue. */
  if (pcb->unsent == NULL) {
    useg = NULL;
  }
  else {
    for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
  }

  /* If there is room in the last pbuf on the unsent queue,
  chain the first pbuf on the queue together with that. */
  if (useg != NULL &&
    TCP_TCPLEN(useg) != 0 &&
    !(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) &&
    !(flags & (TCP_SYN | TCP_FIN)) &&
    useg->len + queue->len <= pcb->mss) {
    /* Remove TCP header from first segment. */
    pbuf_header(queue->p, -TCP_HLEN);
    pbuf_cat(useg->p, queue->p);
    useg->len += queue->len;
    useg->next = queue->next;

    if (seg == queue) seg = NULL;

    memp_free(MEMP_TCP_SEG, queue);
  }
  else {
    if (useg == NULL) {
      pcb->unsent = queue;

    }
    else {
      useg->next = queue;
    }
  }
  if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
    ++len;
  }
  pcb->snd_lbb += len;
  pcb->snd_buf -= len;
  pcb->snd_queuelen = queuelen;
  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %d (after enqueued)\n", pcb->snd_queuelen));
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
      pcb->unsent != NULL);

  }

  /* Set the PSH flag in the last segment that we enqueued, but only
  if the segment has data (indicated by seglen > 0). */
  if (seg != NULL && seglen > 0 && seg->tcphdr != NULL) {
    TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
  }

  return ERR_OK;
  memerr:
  TCP_STATS_INC(tcp.memerr);

  if (queue != NULL) {
    tcp_segs_free(queue);
  }
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
      pcb->unsent != NULL);

  }
  LWIP_DEBUGF(TCP_QLEN_DEBUG | DBG_STATE, ("tcp_enqueue: %d (with mem err)\n", pcb->snd_queuelen));
  return ERR_MEM;
}
/**
 * Reassembles incoming IPv6 fragments into an IPv6 datagram.
 *
 * @param p points to the IPv6 Fragment Header
 * @param len the length of the payload (after Fragment Header)
 * @return NULL if reassembly is incomplete, pbuf pointing to
 *         IPv6 Header if reassembly is complete
 */
struct pbuf *
ip6_reass(struct pbuf *p)
{
  struct ip6_reassdata *ipr, **pipr;
  struct ip6_reass_helper *iprh, *iprh_tmp;
  struct ip6_reass_helper **pnext;
  struct ip6_frag_hdr * frag_hdr;
  size_t unfrag_len;
  u16_t offset, len, start, end, validlen;
  u8_t clen;

  IP6_FRAG_STATS_INC(ip6_frag.recv);

  frag_hdr = (struct ip6_frag_hdr *) p->payload;

  clen = pbuf_clen(p);

  offset = ntohs(frag_hdr->_fragment_offset);

  /* Calculate fragment length from IPv6 payload length.
   * Adjust for headers before Fragment Header.
   * And finally adjust by Fragment Header length. */
  len = ntohs(ip6_current_header()->_plen);
  len -= ((u8_t*)p->payload - (u8_t*)ip6_current_header()) - IP6_HLEN;
  len -= IP6_FRAG_HLEN;

  start = (offset & IP6_FRAG_OFFSET_MASK);
  end = start + len;


  /* Look for the datagram the fragment belongs to in the current datagram queue,
   * remembering the previous in the queue for later dequeueing. */
  for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
    /* Check if the incoming fragment matches the one currently present
       in the reassembly buffer. If so, we proceed with copying the
       fragment into the buffer. */
    if ((frag_hdr->_identification == ipr->identification) &&
        ip6_addr_cmp(ip6_current_src_addr(), &(ipr->iphdr.src)) &&
        ip6_addr_cmp(ip6_current_dest_addr(), &(ipr->iphdr.dest))) {
      IP6_FRAG_STATS_INC(ip6_frag.cachehit);
      break;
    }
  }

  if (ipr == NULL) {
  /* Enqueue a new datagram into the datagram queue */
    ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
    if (ipr == NULL) {
#if IP_REASS_FREE_OLDEST
      /* Make room and try again. */
      ip6_reass_remove_oldest_datagram(ipr, clen);
      ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
      if (ipr == NULL)
#endif /* IP_REASS_FREE_OLDEST */
      {
        IP6_FRAG_STATS_INC(ip6_frag.memerr);
        IP6_FRAG_STATS_INC(ip6_frag.drop);
        goto nullreturn;
      }
    }

    memset(ipr, 0, sizeof(struct ip6_reassdata));
    ipr->timer = IP_REASS_MAXAGE;

    /* enqueue the new structure to the front of the list */
    ipr->next = reassdatagrams;
    reassdatagrams = ipr;

    /* Use the current IPv6 header for src/dest address reference.
     * Eventually, we will replace it when we get the first fragment
     * (it might be this one, in any case, it is done later). */
    SMEMCPY(&ipr->iphdr, ip6_current_header(), IP6_HLEN);
    if (start == 0) {
      ipr->iphdr0 = (struct ip6_hdr *)ip6_current_header();
    }

    /* copy the fragmented packet id. */
    ipr->identification = frag_hdr->_identification;
  }

  /* If this is the last fragment, save total packet length. */
  if ((offset & IP6_FRAG_MORE_FLAG) == 0) {
#if IP_REASS_CHECK_OVERLAP
    if (ipr->datagram_len != 0) {
      IP6_FRAG_STATS_INC(ip6_frag.proterr);
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
    }
#endif /* IP_REASS_CHECK_OVERLAP */
    ipr->datagram_len = end;
  }

  /* find the place to insert this pbuf */
  validlen = 0;
  for (pnext = &ipr->iprh; *pnext != NULL; pnext = &(*pnext)->next) {
    iprh_tmp = *pnext;

    if (start < iprh_tmp->start) {
      /* the new pbuf should be inserted before this */
#if IP_REASS_CHECK_OVERLAP
      if (end > iprh_tmp->start) {
        /* fragment overlaps with following, throw away */
        IP6_FRAG_STATS_INC(ip6_frag.proterr);
        IP6_FRAG_STATS_INC(ip6_frag.drop);
        goto nullreturn;
      }
#endif /* IP_REASS_CHECK_OVERLAP */
      break;
    }
    else if (start == iprh_tmp->start) {
      /* received the same datagram twice: no need to keep the datagram */
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
    }
#if IP_REASS_CHECK_OVERLAP
    else if (start < iprh_tmp->end) {
      /* overlap: no need to keep the new datagram */
      IP6_FRAG_STATS_INC(ip6_frag.proterr);
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
    }
#endif /* IP_REASS_CHECK_OVERLAP */
    else {
      /* Check if the fragments received so far have no gaps. */
      if (validlen == iprh_tmp->start) {
        validlen = iprh_tmp->end;
      }
      else {
        validlen = 0;
      }
    }
  }

  /* Check if we are allowed to enqueue more datagrams. */
  if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
#if IP_REASS_FREE_OLDEST
    ip6_reass_remove_oldest_datagram(ipr, clen);
    if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS)
#endif /* IP_REASS_FREE_OLDEST */
    {
      /* @todo: send ICMPv6 time exceeded here? */
      /* drop this pbuf */
      IP6_FRAG_STATS_INC(ip6_frag.memerr);
      IP6_FRAG_STATS_INC(ip6_frag.drop);
      goto nullreturn;
    }
  }

  if (start == 0 && ipr->iphdr0 == NULL) {
    /*
     * We've got the fragment with offset 0 out of order, remember its
     * IPv6 header location (in the hidden part of the current pbuf)
     * and update the copy in ip6_reassdata::iphdr.  We don't need to
     * copy complete header since src and dest are the same as in the
     * first fragment we received.
     */
    ipr->iphdr0 = (struct ip6_hdr *)ip6_current_header();
    SMEMCPY(&ipr->iphdr, ip6_current_header(),
            IP6_HLEN - 2 * sizeof(ip_addr_p_t));
  }

  /* Overwrite IPv6 Header with our own helper struct (aligned). */
  iprh = (struct ip6_reass_helper *)
    (((uintptr_t)(u8_t *)ip6_current_header() + sizeof(void *) - 1)
     & ~(sizeof(void *) - 1));
  iprh->p = p;
  iprh->start = start;
  iprh->end = end;

  /* insert it into the list */
  iprh->next = *pnext;
  *pnext = iprh;

  /* Track the current number of pbufs current 'in-flight', in order to limit
  the number of fragments that may be enqueued at any one time */
  ip6_reass_pbufcount += clen;

  if (ipr->datagram_len == 0) {
    /* We still don't have the last fragment. */
    return NULL;
  }

  if (validlen == start) {
    validlen = end;
  }
  else {
    /* There are gaps before this fragment. */
    return NULL;
  }

  if (validlen != 0) {
    /*
     * We know we have all the data up to the end of this fragment and
     * we know the total length.  Check if the reassembly is complete.
     */
    for (iprh_tmp = iprh->next; iprh_tmp != NULL; iprh_tmp = iprh_tmp->next) {
      if (validlen == iprh_tmp->start) {
        validlen = iprh_tmp->end;
      }
      else {
        validlen = 0;
        break;
      }
    }

    if (validlen != ipr->datagram_len) {
      /* the datagram is not yet reassembled completely */
      return NULL;
    }
  }

  /*
   * All fragments have been received.  Reassemble original datagram
   * and return it to ip6_input() to be processed instead of the final
   * fragment that completed the reassembly.
   */

  /* chain together the pbufs contained within the ip6_reassdata list. */
  p = NULL;
  for (iprh = ipr->iprh; iprh != NULL; iprh = iprh->next) {
    if (p == NULL) {
      p = iprh->p;
    }
    else {
      /* hide the fragment header for every succeeding fragment */
      pbuf_header(iprh->p, -IP6_FRAG_HLEN);
      pbuf_cat(p, iprh->p);
    }
  }

  /* Adjust datagram length by adding preceding header lengths. */
  unfrag_len = (u8_t *)p->payload - (u8_t *)ipr->iphdr0;
# ifndef VBOX
  ipr->datagram_len += unfrag_len - IP6_HLEN + IP6_FRAG_HLEN;
# else
  LWIP_ASSERT("overflow", (s16_t)unfrag_len == (ssize_t)unfrag_len); /* s16_t because of pbuf_header call */
  ipr->datagram_len += (u16_t)(unfrag_len - IP6_HLEN + IP6_FRAG_HLEN);
# endif

  /* Set payload length in ip header. */
  ipr->iphdr._plen = htons(ipr->datagram_len);

  /* restore IPv6 header (overwritten with ip6_reass_helper) */
  SMEMCPY(ipr->iphdr0, &ipr->iphdr, IP6_HLEN);

  /* Mark as "single fragment" packet (see caller). */
  frag_hdr = (struct ip6_frag_hdr *) p->payload;
  frag_hdr->_fragment_offset = 0;

  /* Unlink from the reassdatagrams list */
  for (pipr = &reassdatagrams; *pipr != NULL; pipr = &(*pipr)->next) {
    if (*pipr == ipr) {
      (*pipr) = ipr->next;
      break;
    }
  }
  memp_free(MEMP_IP6_REASSDATA, ipr);

  /* adjust the number of pbufs currently queued for reassembly. */
  ip6_reass_pbufcount -= pbuf_clen(p);

  /* Move pbuf back to IPv6 header. */
# ifndef VBOX
  if (pbuf_header(p, unfrag_len) != 0) {
# else
  if (pbuf_header(p, (s16_t)unfrag_len) != 0) {
# endif
    LWIP_ASSERT("ip6_reass: moving p->payload to ip6 header failed\n", 0);
    goto nullreturn;
  }

  /* Return the pbuf chain */
  return p;

nullreturn:
  pbuf_free(p);
  return NULL;
}

#endif /* LWIP_IPV6 && LWIP_IPV6_REASS */

#if LWIP_IPV6 && LWIP_IPV6_FRAG

/** Allocate a new struct pbuf_custom_ref */
static struct pbuf_custom_ref*
ip6_frag_alloc_pbuf_custom_ref(void)
{
  return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
}

/** Free a struct pbuf_custom_ref */
static void
ip6_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
{
  LWIP_ASSERT("p != NULL", p != NULL);
  memp_free(MEMP_FRAG_PBUF, p);
}
Exemple #25
0
/**
 * Handle the incoming SLIP stream character by character
 *
 * @param netif the lwip network interface structure for this slipif
 * @param c received character (multiple calls to this function will
 *        return a complete packet, NULL is returned before - used for polling)
 * @return The IP packet when SLIP_END is received
 */
static struct pbuf*
slipif_rxbyte(struct netif *netif, u8_t c)
{
  struct slipif_priv *priv;
  struct pbuf *t;

  LWIP_ASSERT("netif != NULL", (netif != NULL));
  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));

  priv = netif->state;

  switch (priv->state) {
  case SLIP_RECV_NORMAL:
    switch (c) {
    case SLIP_END:
      if (priv->recved > 0) {
        /* Received whole packet. */
        /* Trim the pbuf to the size of the received packet. */
        pbuf_realloc(priv->q, priv->recved);

        LINK_STATS_INC(link.recv);

        LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet (%"U16_F" bytes)\n", priv->recved));
        t = priv->q;
        priv->p = priv->q = NULL;
        priv->i = priv->recved = 0;
        return t;
      }
      return NULL;
    case SLIP_ESC:
      priv->state = SLIP_RECV_ESCAPE;
      return NULL;
    } /* end switch (c) */
    break;
  case SLIP_RECV_ESCAPE:
    /* un-escape END or ESC bytes, leave other bytes
       (although that would be a protocol error) */
    switch (c) {
    case SLIP_ESC_END:
      c = SLIP_END;
      break;
    case SLIP_ESC_ESC:
      c = SLIP_ESC;
      break;
    }
    priv->state = SLIP_RECV_NORMAL;
    break;
  } /* end switch (priv->state) */

  /* byte received, packet not yet completely received */
  if (priv->p == NULL) {
    /* allocate a new pbuf */
    LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
    priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);

    if (priv->p == NULL) {
      LINK_STATS_INC(link.drop);
      LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
      /* don't process any further since we got no pbuf to receive to */
      return NULL;
    }

    if (priv->q != NULL) {
      /* 'chain' the pbuf to the existing chain */
      pbuf_cat(priv->q, priv->p);
    } else {
      /* p is the first pbuf in the chain */
      priv->q = priv->p;
    }
  }

  /* this automatically drops bytes if > SLIP_MAX_SIZE */
  if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
    ((u8_t *)priv->p->payload)[priv->i] = c;
    priv->recved++;
    priv->i++;
    if (priv->i >= priv->p->len) {
      /* on to the next pbuf */
      priv->i = 0;
      if (priv->p->next != NULL && priv->p->next->len > 0) {
        /* p is a chain, on to the next in the chain */
          priv->p = priv->p->next;
      } else {
        /* p is a single pbuf, set it to NULL so next time a new
         * pbuf is allocated */
          priv->p = NULL;
      }
    }
  }
  return NULL;
}
/**
 * Enqueue either data or TCP options (but not both) for tranmission
 * 
 * 
 * 
 * @arg pcb Protocol control block for the TCP connection to enqueue data for.
 * @arg arg Pointer to the data to be enqueued for sending.
 * @arg len Data length in bytes
 * @arg flags
 * @arg copy 1 if data must be copied, 0 if data is non-volatile and can be
 * referenced.
 * @arg optdata
 * @arg optlen
 */
err_t
tcp_enqueue(struct tcp_pcb *pcb, void *arg, u16_t len,
  u8_t flags, u8_t copy,
  u8_t *optdata, u8_t optlen)
{
  struct pbuf *p;
  struct tcp_seg *seg, *useg, *queue;
  u32_t left, seqno;
  u16_t seglen;
  void *ptr;
  u8_t queuelen;

  LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue(pcb=%p, arg=%p, len=%"U16_F", flags=%"X16_F", copy=%"U16_F")\n",
    (void *)pcb, arg, len, (u16_t)flags, (u16_t)copy));
  LWIP_ASSERT("tcp_enqueue: len == 0 || optlen == 0 (programmer violates API)",
      len == 0 || optlen == 0);
  LWIP_ASSERT("tcp_enqueue: arg == NULL || optdata == NULL (programmer violates API)",
      arg == NULL || optdata == NULL);
  /* fail on too much data */
  if (len > pcb->snd_buf) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n", len, pcb->snd_buf));
    return ERR_MEM;
  }
  left = len;
  ptr = arg;

  /* seqno will be the sequence number of the first segment enqueued
   * by the call to this function. */
  seqno = pcb->snd_lbb;

  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));

  /* If total number of pbufs on the unsent/unacked queues exceeds the
   * configured maximum, return an error */
  queuelen = pcb->snd_queuelen;
  if (queuelen >= TCP_SND_QUEUELEN) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too long queue %"U16_F" (max %"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
    TCP_STATS_INC(tcp.memerr);
    return ERR_MEM;
  }
  if (queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: pbufs on queue => at least one queue non-empty",
      pcb->unacked != NULL || pcb->unsent != NULL);
  } else {
    LWIP_ASSERT("tcp_enqueue: no pbufs on queue => both queues empty",
      pcb->unacked == NULL && pcb->unsent == NULL);
  }

  /* First, break up the data into segments and tuck them together in
   * the local "queue" variable. */
  useg = queue = seg = NULL;
  seglen = 0;
  while (queue == NULL || left > 0) {

    /* The segment length should be the MSS if the data to be enqueued
     * is larger than the MSS. */
    seglen = left > pcb->mss? pcb->mss: left;

    /* Allocate memory for tcp_seg, and fill in fields. */
    seg = memp_malloc(MEMP_TCP_SEG);
    if (seg == NULL) {
      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for tcp_seg\n"));
      goto memerr;
    }
    seg->next = NULL;
    seg->p = NULL;

    /* first segment of to-be-queued data? */
    if (queue == NULL) {
      queue = seg;
    }
    /* subsequent segments of to-be-queued data */
    else {
      /* Attach the segment to the end of the queued segments */
      LWIP_ASSERT("useg != NULL", useg != NULL);
      useg->next = seg;
    }
    /* remember last segment of to-be-queued data for next iteration */
    useg = seg;

    /* If copy is set, memory should be allocated
     * and data copied into pbuf, otherwise data comes from
     * ROM or other static memory, and need not be copied. If
     * optdata is != NULL, we have options instead of data. */
     
    /* options? */
    if (optdata != NULL) {
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
        goto memerr;
      }
      ++queuelen;
      seg->dataptr = seg->p->payload;
    }
    /* copy from volatile memory? */
    else if (copy) {
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) {
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
        goto memerr;
      }
      ++queuelen;
      if (arg != NULL) {
        memcpy(seg->p->payload, ptr, seglen);
      }
      seg->dataptr = seg->p->payload;
    }
    /* do not copy data */
    else {
      /* First, allocate a pbuf for holding the data.
       * since the referenced data is available at least until it is sent out on the
       * link (as it has to be ACKed by the remote party) we can safely use PBUF_ROM
       * instead of PBUF_REF here.
       */
      if ((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for zero-copy pbuf\n"));
        goto memerr;
      }
      ++queuelen;
      /* reference the non-volatile payload data */
      p->payload = ptr;
      seg->dataptr = ptr;

      /* Second, allocate a pbuf for the headers. */
      if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) {
        /* If allocation fails, we have to deallocate the data pbuf as
         * well. */
        pbuf_free(p);
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for header pbuf\n"));
        goto memerr;
      }
      ++queuelen;

      /* Concatenate the headers and data pbufs together. */
      pbuf_cat(seg->p/*header*/, p/*data*/);
      p = NULL;
    }

    /* Now that there are more segments queued, we check again if the
    length of the queue exceeds the configured maximum. */
    if (queuelen > TCP_SND_QUEUELEN) {
      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
      goto memerr;
    }

    seg->len = seglen;

    /* build TCP header */
    if (pbuf_header(seg->p, TCP_HLEN)) {
      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: no room for TCP header in pbuf.\n"));
      TCP_STATS_INC(tcp.err);
      goto memerr;
    }
    seg->tcphdr = seg->p->payload;
    seg->tcphdr->src = htons(pcb->local_port);
    seg->tcphdr->dest = htons(pcb->remote_port);
    seg->tcphdr->seqno = htonl(seqno);
    seg->tcphdr->urgp = 0;
    TCPH_FLAGS_SET(seg->tcphdr, flags);
    /* don't fill in tcphdr->ackno and tcphdr->wnd until later */

    /* Copy the options into the header, if they are present. */
    if (optdata == NULL) {
      TCPH_HDRLEN_SET(seg->tcphdr, 5);
    }
    else {
      TCPH_HDRLEN_SET(seg->tcphdr, (5 + optlen / 4));
      /* Copy options into data portion of segment.
       Options can thus only be sent in non data carrying
       segments such as SYN|ACK. */
      memcpy(seg->dataptr, optdata, optlen);
    }
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE, ("tcp_enqueue: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
      ntohl(seg->tcphdr->seqno),
      ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
      (u16_t)flags));

    left -= seglen;
    seqno += seglen;
    ptr = (void *)((u8_t *)ptr + seglen);
  }

  /* Now that the data to be enqueued has been broken up into TCP
  segments in the queue variable, we add them to the end of the
  pcb->unsent queue. */
  if (pcb->unsent == NULL) {
    useg = NULL;
  }
  else {
    for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
  }
  /* { useg is last segment on the unsent queue, NULL if list is empty } */

  /* If there is room in the last pbuf on the unsent queue,
  chain the first pbuf on the queue together with that. */
  if (useg != NULL &&
    TCP_TCPLEN(useg) != 0 &&
    !(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) &&
    !(flags & (TCP_SYN | TCP_FIN)) &&
    /* fit within max seg size */
    useg->len + queue->len <= pcb->mss) {
    /* Remove TCP header from first segment of our to-be-queued list */
    pbuf_header(queue->p, -TCP_HLEN);
    pbuf_cat(useg->p, queue->p);
    useg->len += queue->len;
    useg->next = queue->next;

    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE | DBG_STATE, ("tcp_enqueue: chaining segments, new len %"U16_F"\n", useg->len));
    if (seg == queue) {
      seg = NULL;
    }
    memp_free(MEMP_TCP_SEG, queue);
  }
  else {
    /* empty list */
    if (useg == NULL) {
      /* initialize list with this segment */
      pcb->unsent = queue;
    }
    /* enqueue segment */
    else {
      useg->next = queue;
    }
  }
  if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
    ++len;
  }
  pcb->snd_lbb += len;

  pcb->snd_buf -= len;

  /* update number of segments on the queues */
  pcb->snd_queuelen = queuelen;
  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: valid queue length",
      pcb->unacked != NULL || pcb->unsent != NULL);
  }

  /* Set the PSH flag in the last segment that we enqueued, but only
  if the segment has data (indicated by seglen > 0). */
  if (seg != NULL && seglen > 0 && seg->tcphdr != NULL) {
    TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
  }

  return ERR_OK;
memerr:
  TCP_STATS_INC(tcp.memerr);

  if (queue != NULL) {
    tcp_segs_free(queue);
  }
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
      pcb->unsent != NULL);
  }
  LWIP_DEBUGF(TCP_QLEN_DEBUG | DBG_STATE, ("tcp_enqueue: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
  return ERR_MEM;
}
Exemple #27
0
/** http client tcp recv callback */
static err_t
httpc_tcp_recv(void *arg, struct altcp_pcb *pcb, struct pbuf *p, err_t r)
{
  httpc_state_t* req = (httpc_state_t*)arg;
  LWIP_UNUSED_ARG(r);

  if (p == NULL) {
    httpc_result_t result;
    if (req->parse_state != HTTPC_PARSE_RX_DATA) {
      /* did not get RX data yet */
      result = HTTPC_RESULT_ERR_CLOSED;
    } else if ((req->hdr_content_len != HTTPC_CONTENT_LEN_INVALID) &&
      (req->hdr_content_len != req->rx_content_len)) {
      /* header has been received with content length but not all data received */
      result = HTTPC_RESULT_ERR_CONTENT_LEN;
    } else {
      /* receiving data and either all data received or no content length header */
      result = HTTPC_RESULT_OK;
    }
    return httpc_close(req, result, req->rx_status, ERR_OK);
  }
  if (req->parse_state != HTTPC_PARSE_RX_DATA) {
    if (req->rx_hdrs == NULL) {
      req->rx_hdrs = p;
    } else {
      pbuf_cat(req->rx_hdrs, p);
    }
    if (req->parse_state == HTTPC_PARSE_WAIT_FIRST_LINE) {
      u16_t status_str_off;
      err_t err = http_parse_response_status(req->rx_hdrs, &req->rx_http_version, &req->rx_status, &status_str_off);
      if (err == ERR_OK) {
        /* don't care status string */
        req->parse_state = HTTPC_PARSE_WAIT_HEADERS;
      }
    }
    if (req->parse_state == HTTPC_PARSE_WAIT_HEADERS) {
      u16_t total_header_len;
      err_t err = http_wait_headers(req->rx_hdrs, &req->hdr_content_len, &total_header_len);
      if (err == ERR_OK) {
        struct pbuf *q;
        /* full header received, send window update for header bytes and call into client callback */
        altcp_recved(pcb, total_header_len);
        if (req->conn_settings) {
          if (req->conn_settings->headers_done_fn) {
            err = req->conn_settings->headers_done_fn(req, req->callback_arg, req->rx_hdrs, total_header_len, req->hdr_content_len);
            if (err != ERR_OK) {
              return httpc_close(req, HTTPC_RESULT_LOCAL_ABORT, req->rx_status, err);
            }
          }
        }
        /* hide header bytes in pbuf */
        q = pbuf_free_header(req->rx_hdrs, total_header_len);
        p = q;
        req->rx_hdrs = NULL;
        /* go on with data */
        req->parse_state = HTTPC_PARSE_RX_DATA;
      }
    }
  }
  if ((p != NULL) && (req->parse_state == HTTPC_PARSE_RX_DATA)) {
    req->rx_content_len += p->tot_len;
    if (req->recv_fn != NULL) {
      /* directly return here: the connection migth already be aborted from the callback! */
      return req->recv_fn(req->callback_arg, pcb, p, r);
    } else {
      altcp_recved(pcb, p->tot_len);
      pbuf_free(p);
    }
  }
  return ERR_OK;
}
Exemple #28
0
/**
 * Create a TCP segment with prefilled header.
 *
 * Called by tcp_write and tcp_enqueue_flags.
 *
 * @param pcb Protocol control block for the TCP connection.
 * @param p pbuf that is used to hold the TCP header.
 * @param flags TCP flags for header.
 * @param seqno TCP sequence number of this packet
 * @param optflags options to include in TCP header
 * @return a new tcp_seg pointing to p, or NULL.
 * The TCP header is filled in except ackno and wnd.
 * p is freed on failure.
 */
static struct tcp_seg *
tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
{
  struct tcp_seg *seg;
  u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);

#if LWIP_3RD_PARTY_BUFS
  if ((seg = external_tcp_seg_alloc(pcb)) == NULL) {
#else
  if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
#endif
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
    tcp_tx_pbuf_free(pcb, p);
    return NULL;
  }
  seg->flags = optflags;
  seg->next = NULL;
  seg->p = p;
  seg->dataptr = p->payload;
  seg->len = p->tot_len - optlen;
#if TCP_OVERSIZE_DBGCHECK
  seg->oversize_left = 0;
#endif /* TCP_OVERSIZE_DBGCHECK */
#if TCP_CHECKSUM_ON_COPY
  seg->chksum = 0;
  seg->chksum_swapped = 0;
  /* check optflags */
  LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
              (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
#endif /* TCP_CHECKSUM_ON_COPY */
  seg->seqno = seqno;

  /* build TCP header */
  if (pbuf_header(p, TCP_HLEN)) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
    TCP_STATS_INC(tcp.err);
    tcp_tx_seg_free(pcb, seg);
    return NULL;
  }
  seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
  seg->tcphdr->src = htons(pcb->local_port);
  seg->tcphdr->dest = htons(pcb->remote_port);
  seg->tcphdr->seqno = htonl(seqno);
  /* ackno is set in tcp_output */
  TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
  /* wnd and chksum are set in tcp_output */
  seg->tcphdr->urgp = 0;
  return seg;
} 

/**
 * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
 *
 * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
 * there may be extra bytes available at the end.
 *
 * @param layer flag to define header size.
 * @param length size of the pbuf's payload.
 * @param max_length maximum usable size of payload+oversize.
 * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
 * @param pcb The TCP connection that willo enqueue the pbuf.
 * @param apiflags API flags given to tcp_write.
 * @param first_seg true when this pbuf will be used in the first enqueued segment.
 * @param 
 */
static struct pbuf *
tcp_pbuf_prealloc(u16_t length, u16_t max_length,
                  u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
                  u8_t first_seg)
{
  struct pbuf *p;
  u16_t alloc = length;

  if (length < max_length) {
    /* Should we allocate an oversized pbuf, or just the minimum
     * length required? If tcp_write is going to be called again
     * before this segment is transmitted, we want the oversized
     * buffer. If the segment will be transmitted immediately, we can
     * save memory by allocating only length. We use a simple
     * heuristic based on the following information:
     *
     * Did the user set TCP_WRITE_FLAG_MORE?
     *
     * Will the Nagle algorithm defer transmission of this segment?
     */
    if ((apiflags & TCP_WRITE_FLAG_MORE) ||
        (!(pcb->flags & TF_NODELAY) &&
         (!first_seg ||
          pcb->unsent != NULL ||
          pcb->unacked != NULL))) {
          alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + pcb->tcp_oversize_val));
    }
  }
  p = tcp_tx_pbuf_alloc(pcb, alloc, PBUF_RAM);
  if (p == NULL) {
    return NULL;
  }
  LWIP_ASSERT("need unchained pbuf", p->next == NULL);
  *oversize = p->len - length;
  /* trim p->len to the currently used size */
  p->len = p->tot_len = length;
  return p;
}

/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
 *
 * @param pcb the tcp pcb to check for
 * @param len length of data to send (checked agains snd_buf)
 * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
 */
static err_t
tcp_write_checks(struct tcp_pcb *pcb, u32_t len)
{
  /* connection is in invalid state for data transmission? */
  if ((get_tcp_state(pcb) != ESTABLISHED) &&
      (get_tcp_state(pcb) != CLOSE_WAIT) &&
      (get_tcp_state(pcb) != SYN_SENT) &&
      (get_tcp_state(pcb) != SYN_RCVD)) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
    return ERR_CONN;
  } else if (len == 0) {
    return ERR_OK;
  }

  /* fail on too much data */
  if (len > pcb->snd_buf) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U32_F" > snd_buf=%"U32_F")\n",
      len, pcb->snd_buf));
    pcb->flags |= TF_NAGLEMEMERR;
    return ERR_MEM;
  }
  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U32_F"\n", (u32_t)pcb->snd_queuelen));

  /* If total number of pbufs on the unsent/unacked queues exceeds the
   * configured maximum, return an error */
  /* check for configured max queuelen and possible overflow */
  if ((pcb->snd_queuelen >= pcb->max_unsent_len) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U32_F" (max %"U32_F")\n",
      pcb->snd_queuelen, pcb->max_unsent_len));
    TCP_STATS_INC(tcp.memerr);
    pcb->flags |= TF_NAGLEMEMERR;
    return ERR_MEM;
  }
  if (pcb->snd_queuelen != 0) {
  } else {
    LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
      pcb->unacked == NULL && pcb->unsent == NULL);
  }
  return ERR_OK;
}

/**
 * Write data for sending (but does not send it immediately).
 *
 * It waits in the expectation of more data being sent soon (as
 * it can send them more efficiently by combining them together).
 * To prompt the system to send data now, call tcp_output() after
 * calling tcp_write().
 *
 * @param pcb Protocol control block for the TCP connection to enqueue data for.
 * @param arg Pointer to the data to be enqueued for sending.
 * @param len Data length in bytes
 * @param apiflags combination of following flags :
 * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
 * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
 * @return ERR_OK if enqueued, another err_t on error
 */
err_t
tcp_write(struct tcp_pcb *pcb, const void *arg, u32_t len, u8_t apiflags)
{
  struct pbuf *concat_p = NULL;
  struct tcp_seg *seg = NULL, *prev_seg = NULL, *queue = NULL;
  u32_t pos = 0; /* position in 'arg' data */
  u32_t queuelen;
  u8_t optlen = 0;
  u8_t optflags = 0;
#if TCP_OVERSIZE
  u16_t oversize = 0;
  u16_t oversize_used = 0;
#endif /* TCP_OVERSIZE */
#if TCP_CHECKSUM_ON_COPY
  u16_t concat_chksum = 0;
  u8_t concat_chksum_swapped = 0;
  u16_t concat_chksummed = 0;
#endif /* TCP_CHECKSUM_ON_COPY */
  err_t err;
  /* don't allocate segments bigger than half the maximum window we ever received */
  u16_t mss_local = LWIP_MIN(pcb->mss, pcb->snd_wnd_max/2);
  mss_local = mss_local ? mss_local : pcb->mss;

  int byte_queued = pcb->snd_nxt - pcb->lastack;
  if ( len < pcb->mss)
          pcb->snd_sml_add = (pcb->unacked ? pcb->unacked->len : 0) + byte_queued;

#if LWIP_NETIF_TX_SINGLE_PBUF
  /* Always copy to try to create single pbufs for TX */
  apiflags |= TCP_WRITE_FLAG_COPY;
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */

  LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
    (void *)pcb, arg, len, (u16_t)apiflags));
  LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)", 
             arg != NULL, return ERR_ARG;);

  err = tcp_write_checks(pcb, len);
  if (err != ERR_OK) {
    return err;
  }
  queuelen = pcb->snd_queuelen;

#if LWIP_TCP_TIMESTAMPS
  if ((pcb->flags & TF_TIMESTAMP)) {
    optflags = TF_SEG_OPTS_TS;
    /* ensure that segments can hold at least one data byte... */
    mss_local = LWIP_MAX(mss_local, LWIP_TCP_OPT_LEN_TS + 1);
  }
#endif /* LWIP_TCP_TIMESTAMPS */
  optlen = LWIP_TCP_OPT_LENGTH( optflags );

  /*
   * TCP segmentation is done in three phases with increasing complexity:
   *
   * 1. Copy data directly into an oversized pbuf.
   * 2. Chain a new pbuf to the end of pcb->unsent.
   * 3. Create new segments.
   *
   * We may run out of memory at any point. In that case we must
   * return ERR_MEM and not change anything in pcb. Therefore, all
   * changes are recorded in local variables and committed at the end
   * of the function. Some pcb fields are maintained in local copies:
   *
   * queuelen = pcb->snd_queuelen
   * oversize = pcb->unsent_oversize
   *
   * These variables are set consistently by the phases:
   *
   * seg points to the last segment tampered with.
   *
   * pos records progress as data is segmented.
   */

  /* Find the tail of the unsent queue. */
  if (pcb->unsent != NULL) {
    u16_t space;
    u16_t unsent_optlen;

    if (!pcb->last_unsent || pcb->last_unsent->next) {
      /* @todo: this could be sped up by keeping last_unsent in the pcb */
      for (pcb->last_unsent = pcb->unsent; pcb->last_unsent->next != NULL;
           pcb->last_unsent = pcb->last_unsent->next);
    }
    /* Usable space at the end of the last unsent segment */
    unsent_optlen = LWIP_TCP_OPT_LENGTH(pcb->last_unsent->flags);
    LWIP_ASSERT("mss_local is too small", mss_local >= pcb->last_unsent->len + unsent_optlen);
    space = mss_local - (pcb->last_unsent->len + unsent_optlen);

    /*
     * Phase 1: Copy data directly into an oversized pbuf.
     *
     * The number of bytes copied is recorded in the oversize_used
     * variable. The actual copying is done at the bottom of the
     * function.
     */
#if TCP_OVERSIZE
#if TCP_OVERSIZE_DBGCHECK
    /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
    LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
                pcb->unsent_oversize == pcb->last_unsent->oversize_left);
#endif /* TCP_OVERSIZE_DBGCHECK */
    oversize = pcb->unsent_oversize;
    if (oversize > 0) {
      LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
      seg = pcb->last_unsent;
      oversize_used = oversize < len ? oversize : len;
      pos += oversize_used;
      oversize -= oversize_used;
      space -= oversize_used;
    }
    /* now we are either finished or oversize is zero */
    LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
#endif /* TCP_OVERSIZE */

    /*
     * Phase 2: Chain a new pbuf to the end of pcb->unsent.
     *
     * We don't extend segments containing SYN/FIN flags or options
     * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
     * the end.
     */
    if ((pos < len) && (space > 0) && (pcb->last_unsent->len > 0)) {
      u16_t seglen = space < len - pos ? space : len - pos;
      seg = pcb->last_unsent;

      /* Create a pbuf with a copy or reference to seglen bytes. We
       * can use PBUF_RAW here since the data appears in the middle of
       * a segment. A header will never be prepended. */
      if (apiflags & TCP_WRITE_FLAG_COPY) {
        /* Data is copied */
        if ((concat_p = tcp_pbuf_prealloc(seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
          LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
                      ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
                       seglen));
          goto memerr;
        }
#if TCP_OVERSIZE_DBGCHECK
        pcb->last_unsent->oversize_left += oversize;
#endif /* TCP_OVERSIZE_DBGCHECK */
        TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
#if TCP_CHECKSUM_ON_COPY
        concat_chksummed += seglen;
#endif /* TCP_CHECKSUM_ON_COPY */
      } else {
    	  LWIP_ASSERT("tcp_write : we are never here", 0);
    	  goto memerr;
      }

      pos += seglen;
      queuelen += pbuf_clen(concat_p);
    }
  } else {
#if TCP_OVERSIZE
    pcb->last_unsent = NULL;
    LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
                pcb->unsent_oversize == 0);
#endif /* TCP_OVERSIZE */
  }

  /*
   * Phase 3: Create new segments.
   *
   * The new segments are chained together in the local 'queue'
   * variable, ready to be appended to pcb->unsent.
   */
  while (pos < len) {
    struct pbuf *p;
    u32_t left = len - pos;
    u16_t max_len = mss_local - optlen;
    u16_t seglen = left > max_len ? max_len : left;

    if (apiflags & TCP_WRITE_FLAG_COPY) {
      /* If copy is set, memory should be allocated and data copied
       * into pbuf */
      if ((p = tcp_pbuf_prealloc(seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
        goto memerr;
      }
      LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
                  (p->len >= seglen));
      TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
    } else {
    	LWIP_ASSERT("tcp_write: we are never here",0);
    	goto memerr;
    }

    queuelen += pbuf_clen(p);

    /* Now that there are more segments queued, we check again if the
     * length of the queue exceeds the configured maximum or
     * overflows. */
    if ((queuelen > pcb->max_unsent_len) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U32_F" (%"U32_F")\n", queuelen, pcb->max_unsent_len));
      tcp_tx_pbuf_free(pcb, p);
      goto memerr;
    }

    if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
      goto memerr;
    }
#if TCP_OVERSIZE_DBGCHECK
    seg->oversize_left = oversize;
#endif /* TCP_OVERSIZE_DBGCHECK */
#if TCP_CHECKSUM_ON_COPY
    seg->chksum = chksum;
    seg->chksum_swapped = chksum_swapped;
    seg->flags |= TF_SEG_DATA_CHECKSUMMED;
#endif /* TCP_CHECKSUM_ON_COPY */
    /* Fix dataptr for the nocopy case */
    if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
      seg->dataptr = (u8_t*)arg + pos;
    }

    /* first segment of to-be-queued data? */
    if (queue == NULL) {
      queue = seg;
    } else {
      /* Attach the segment to the end of the queued segments */
      LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
      prev_seg->next = seg;
    }
    /* remember last segment of to-be-queued data for next iteration */
    prev_seg = seg;

    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
      ntohl(seg->tcphdr->seqno),
      ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));

    pos += seglen;
  }

  /*
   * All three segmentation phases were successful. We can commit the
   * transaction.
   */

  /*
   * Phase 1: If data has been added to the preallocated tail of
   * last_unsent, we update the length fields of the pbuf chain.
   */
#if TCP_OVERSIZE
  if (oversize_used > 0) {
    struct pbuf *p;
    /* Bump tot_len of whole chain, len of tail */
    for (p = pcb->last_unsent->p; p; p = p->next) {
      p->tot_len += oversize_used;
      if (p->next == NULL) {
        TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, pcb->last_unsent);
        p->len += oversize_used;
      }
    }
    pcb->last_unsent->len += oversize_used;
#if TCP_OVERSIZE_DBGCHECK
    pcb->last_unsent->oversize_left -= oversize_used;
#endif /* TCP_OVERSIZE_DBGCHECK */
  }
  pcb->unsent_oversize = oversize;
#endif /* TCP_OVERSIZE */

  /*
   * Phase 2: concat_p can be concatenated onto pcb->last_unsent->p
   */
  if (concat_p != NULL) {
    LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
      (pcb->last_unsent != NULL));
    pbuf_cat(pcb->last_unsent->p, concat_p);
    pcb->last_unsent->len += concat_p->tot_len;
#if TCP_CHECKSUM_ON_COPY
    if (concat_chksummed) {
      tcp_seg_add_chksum(concat_chksum, concat_chksummed, &pcb->last_unsent->chksum,
        &pcb->last_unsent->chksum_swapped);
      pcb->last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
    }
#endif /* TCP_CHECKSUM_ON_COPY */
  }

  /*
   * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
   * is harmless
   */
  if (pcb->last_unsent == NULL) {
    pcb->unsent = queue;
  } else {
    pcb->last_unsent->next = queue;
  }
  pcb->last_unsent = seg;

  /*
   * Finally update the pcb state.
   */
  pcb->snd_lbb += len;
  pcb->snd_buf -= len;
  pcb->snd_queuelen = queuelen;

  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
    pcb->snd_queuelen));
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_write: valid queue length",
                pcb->unacked != NULL || pcb->unsent != NULL);
  }

  /* Set the PSH flag in the last segment that we enqueued. */
  if (seg != NULL && seg->tcphdr != NULL) {
    TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
  }

  return ERR_OK;
memerr:
  pcb->flags |= TF_NAGLEMEMERR;
  TCP_STATS_INC(tcp.memerr);

  if (concat_p != NULL) {
    tcp_tx_pbuf_free(pcb, concat_p);
  }
  if (queue != NULL) {
    tcp_tx_segs_free(pcb, queue);
  }
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
      pcb->unsent != NULL);
  }
  LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
  return ERR_MEM;
}
Exemple #29
0
/**
 * Fragment an IP datagram if too large for the netif.
 *
 * Chop the datagram in MTU sized chunks and send them in order
 * by using a fixed size static memory buffer (PBUF_REF) or
 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
 *
 * @param p ip packet to send
 * @param netif the netif on which to send
 * @param dest destination ip address to which to send
 *
 * @return ERR_OK if sent successfully, err_t otherwise
 */
err_t 
ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
{
  struct pbuf *rambuf;
#if IP_FRAG_USES_STATIC_BUF
  struct pbuf *header;
#else
#if !LWIP_NETIF_TX_SINGLE_PBUF
  struct pbuf *newpbuf;
#endif
  struct ip_hdr *original_iphdr;
#endif
  struct ip_hdr *iphdr;
  u16_t nfb;
  u16_t left, cop;
  u16_t mtu = netif->mtu;
  u16_t ofo, omf;
  u16_t last;
  u16_t poff = IP_HLEN;
  u16_t tmp;
#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
  u16_t newpbuflen = 0;
  u16_t left_to_copy;
#endif

  /* Get a RAM based MTU sized pbuf */
#if IP_FRAG_USES_STATIC_BUF
  /* When using a static buffer, we use a PBUF_REF, which we will
   * use to reference the packet (without link header).
   * Layer and length is irrelevant.
   */
  rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
  if (rambuf == NULL) {
    LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
    return ERR_MEM;
  }
  rambuf->tot_len = rambuf->len = mtu;
  rambuf->payload = LWIP_MEM_ALIGN((void *)buf);

  /* Copy the IP header in it */
  iphdr = (struct ip_hdr *)rambuf->payload;
  SMEMCPY(iphdr, p->payload, IP_HLEN);
#else /* IP_FRAG_USES_STATIC_BUF */
  original_iphdr = (struct ip_hdr *)p->payload;
  iphdr = original_iphdr;
#endif /* IP_FRAG_USES_STATIC_BUF */

  /* Save original offset */
  tmp = ntohs(IPH_OFFSET(iphdr));
  ofo = tmp & IP_OFFMASK;
  omf = tmp & IP_MF;

  left = p->tot_len - IP_HLEN;

  nfb = (mtu - IP_HLEN) / 8;

  while (left) {
    last = (left <= mtu - IP_HLEN);

    /* Set new offset and MF flag */
    tmp = omf | (IP_OFFMASK & (ofo));
    if (!last) {
      tmp = tmp | IP_MF;
    }

    /* Fill this fragment */
    cop = last ? left : nfb * 8;

#if IP_FRAG_USES_STATIC_BUF
    poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
#else /* IP_FRAG_USES_STATIC_BUF */
#if LWIP_NETIF_TX_SINGLE_PBUF
    rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
    if (rambuf == NULL) {
      return ERR_MEM;
    }
    LWIP_ASSERT("this needs a pbuf in one piece!",
      (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
    poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
    /* make room for the IP header */
    if(pbuf_header(rambuf, IP_HLEN)) {
      pbuf_free(rambuf);
      return ERR_MEM;
    }
    /* fill in the IP header */
    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
    iphdr = rambuf->payload;
#else /* LWIP_NETIF_TX_SINGLE_PBUF */
    /* When not using a static buffer, create a chain of pbufs.
     * The first will be a PBUF_RAM holding the link and IP header.
     * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
     * but limited to the size of an mtu.
     */
    rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
    if (rambuf == NULL) {
      return ERR_MEM;
    }
    LWIP_ASSERT("this needs a pbuf in one piece!",
                (p->len >= (IP_HLEN)));
    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
    iphdr = (struct ip_hdr *)rambuf->payload;

    /* Can just adjust p directly for needed offset. */
    p->payload = (u8_t *)p->payload + poff;
    p->len -= poff;

    left_to_copy = cop;
    while (left_to_copy) {
      struct pbuf_custom_ref *pcr;
      newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
      /* Is this pbuf already empty? */
      if (!newpbuflen) {
        p = p->next;
        continue;
      }
      pcr = ip_frag_alloc_pbuf_custom_ref();
      if (pcr == NULL) {
        pbuf_free(rambuf);
        return ERR_MEM;
      }
      /* Mirror this pbuf, although we might not need all of it. */
      newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
      if (newpbuf == NULL) {
        ip_frag_free_pbuf_custom_ref(pcr);
        pbuf_free(rambuf);
        return ERR_MEM;
      }
      pbuf_ref(p);
      pcr->original = p;
      pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;

      /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
       * so that it is removed when pbuf_dechain is later called on rambuf.
       */
      pbuf_cat(rambuf, newpbuf);
      left_to_copy -= newpbuflen;
      if (left_to_copy) {
        p = p->next;
      }
    }
    poff = newpbuflen;
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
#endif /* IP_FRAG_USES_STATIC_BUF */

    /* Correct header */
    IPH_OFFSET_SET(iphdr, htons(tmp));
    IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
    IPH_CHKSUM_SET(iphdr, 0);
    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));

#if IP_FRAG_USES_STATIC_BUF
    if (last) {
      pbuf_realloc(rambuf, left + IP_HLEN);
    }

    /* This part is ugly: we alloc a RAM based pbuf for 
     * the link level header for each chunk and then 
     * free it.A PBUF_ROM style pbuf for which pbuf_header
     * worked would make things simpler.
     */
    header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
    if (header != NULL) {
      pbuf_chain(header, rambuf);
      netif->output(netif, header, dest);
      IPFRAG_STATS_INC(ip_frag.xmit);
      snmp_inc_ipfragcreates();
      pbuf_free(header);
    } else {
      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
      pbuf_free(rambuf);
      return ERR_MEM;
    }
#else /* IP_FRAG_USES_STATIC_BUF */
    /* No need for separate header pbuf - we allowed room for it in rambuf
     * when allocated.
     */
    netif->output(netif, rambuf, dest);
    IPFRAG_STATS_INC(ip_frag.xmit);

    /* Unfortunately we can't reuse rambuf - the hardware may still be
     * using the buffer. Instead we free it (and the ensuing chain) and
     * recreate it next time round the loop. If we're lucky the hardware
     * will have already sent the packet, the free will really free, and
     * there will be zero memory penalty.
     */
    
    pbuf_free(rambuf);
#endif /* IP_FRAG_USES_STATIC_BUF */
    left -= cop;
    ofo += nfb;
  }
#if IP_FRAG_USES_STATIC_BUF
  pbuf_free(rambuf);
#endif /* IP_FRAG_USES_STATIC_BUF */
  snmp_inc_ipfragoks();
  return ERR_OK;
}
Exemple #30
0
/**
 * Handle the incoming SLIP stream character by character
 *
 * Poll the serial layer by calling sio_recv()
 * 
 * @return The IP packet when SLIP_END is received 
 */
static struct pbuf *
slipif_input(struct netif *netif)
{
  u8_t c;
  struct pbuf *p, *q;
  int recved;
  int i;

  q = p = NULL;
  recved = i = 0;
  c = 0;

  while (1) {
    c = sio_recv(netif->state);
    switch (c) {
    case SLIP_END:
      if (recved > 0) {
        /* Received whole packet. */
        pbuf_realloc(q, recved);
        
        LINK_STATS_INC(link.recv);
        
        LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
        return q;
      }
      break;

    case SLIP_ESC:
      c = sio_recv(netif->state);
      switch (c) {
      case SLIP_ESC_END:
        c = SLIP_END;
        break;
      case SLIP_ESC_ESC:
        c = SLIP_ESC;
        break;
      }
      /* FALLTHROUGH */

    default:
      if (p == NULL) {
        LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
        p = pbuf_alloc(PBUF_LINK, PBUF_POOL_BUFSIZE, PBUF_POOL);

        if (p == NULL) {
          LINK_STATS_INC(link.drop);
          LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
        }

        if (q != NULL) {
          pbuf_cat(q, p);
        } else {
          q = p;
        }
      }
      if (p != NULL && recved < MAX_SIZE) {
        ((u8_t *)p->payload)[i] = c;
        recved++;
        i++;
        if (i >= p->len) {
          i = 0;
          if (p->next != NULL && p->next->len > 0)
            p = p->next;
          else
            p = NULL;
        }
      }
      break;
    }

  }
  return NULL;
}