Ejemplo n.º 1
0
void tcp_wrbuffer_dump(FAR const char *msg, FAR struct tcp_wrbuffer_s *wrb,
                       unsigned int len, unsigned int offset)
{
  lowsyslog(LOG_DEBUG, "%s: wrb=%p segno=%d sent=%d nrtx=%d\n",
            msg, wrb, WRB_SEQNO(wrb), WRB_SENT(wrb), WRB_NRTX(wrb));
  iob_dump("I/O Buffer Chain", WRB_IOB(wrb), len, offset);
}
Ejemplo n.º 2
0
static uint16_t psock_send_interrupt(FAR struct net_driver_s *dev,
                                     FAR void *pvconn, FAR void *pvpriv,
                                     uint16_t flags)
{
    FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
    FAR struct socket *psock = (FAR struct socket *)pvpriv;

    nllvdbg("flags: %04x\n", flags);

    /* If this packet contains an acknowledgement, then update the count of
     * acknowledged bytes.
     */

    if ((flags & TCP_ACKDATA) != 0)
    {
        FAR struct tcp_wrbuffer_s *wrb;
        FAR sq_entry_t *entry;
        FAR sq_entry_t *next;
        uint32_t ackno;

        ackno = tcp_getsequence(TCPBUF->ackno);
        nllvdbg("ACK: ackno=%u flags=%04x\n", ackno, flags);

        /* Look at every write buffer in the unacked_q.  The unacked_q
         * holds write buffers that have been entirely sent, but which
         * have not yet been ACKed.
         */

        for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
        {
            uint32_t lastseq;

            /* Check of some or all of this write buffer has been ACKed. */

            next = sq_next(entry);
            wrb = (FAR struct tcp_wrbuffer_s*)entry;

            /* If the ACKed sequence number is greater than the start
             * sequence number of the write buffer, then some or all of
             * the write buffer has been ACKed.
             */

            if (ackno > WRB_SEQNO(wrb))
            {
                /* Get the sequence number at the end of the data */

                lastseq = WRB_SEQNO(wrb) + WRB_PKTLEN(wrb);
                nllvdbg("ACK: wrb=%p seqno=%u lastseq=%u pktlen=%u ackno=%u\n",
                        wrb, WRB_SEQNO(wrb), lastseq, WRB_PKTLEN(wrb), ackno);

                /* Has the entire buffer been ACKed? */

                if (ackno >= lastseq)
                {
                    nllvdbg("ACK: wrb=%p Freeing write buffer\n", wrb);

                    /* Yes... Remove the write buffer from ACK waiting queue */

                    sq_rem(entry, &conn->unacked_q);

                    /* And return the write buffer to the pool of free buffers */

                    tcp_wrbuffer_release(wrb);
                }
                else
                {
                    unsigned int trimlen;

                    /* No, then just trim the ACKed bytes from the beginning
                     * of the write buffer.  This will free up some I/O buffers
                     * that can be reused while are still sending the last
                     * buffers in the chain.
                     */

                    trimlen = ackno - WRB_SEQNO(wrb);
                    if (trimlen > WRB_SENT(wrb))
                    {
                        /* More data has been ACKed then we have sent? */

                        trimlen = WRB_SENT(wrb);
                    }

                    nllvdbg("ACK: wrb=%p trim %u bytes\n", wrb, trimlen);

                    WRB_TRIM(wrb, trimlen);
                    WRB_SEQNO(wrb) = ackno;
                    WRB_SENT(wrb) -= trimlen;

                    /* Set the new sequence number for what remains */

                    nllvdbg("ACK: wrb=%p seqno=%u pktlen=%u\n",
                            wrb, WRB_SEQNO(wrb), WRB_PKTLEN(wrb));
                }
            }
        }

        /* A special case is the head of the write_q which may be partially
         * sent and so can still have un-ACKed bytes that could get ACKed
         * before the entire write buffer has even been sent.
         */

        wrb = (FAR struct tcp_wrbuffer_s*)sq_peek(&conn->write_q);
        if (wrb && WRB_SENT(wrb) > 0 && ackno > WRB_SEQNO(wrb))
        {
            uint32_t nacked;

            /* Number of bytes that were ACKed */

            nacked = ackno - WRB_SEQNO(wrb);
            if (nacked > WRB_SENT(wrb))
            {
                /* More data has been ACKed then we have sent? ASSERT? */

                nacked = WRB_SENT(wrb);
            }

            nllvdbg("ACK: wrb=%p seqno=%u nacked=%u sent=%u ackno=%u\n",
                    wrb, WRB_SEQNO(wrb), nacked, WRB_SENT(wrb), ackno);

            /* Trim the ACKed bytes from the beginning of the write buffer. */

            WRB_TRIM(wrb, nacked);
            WRB_SEQNO(wrb) = ackno;
            WRB_SENT(wrb) -= nacked;

            nllvdbg("ACK: wrb=%p seqno=%u pktlen=%u sent=%u\n",
                    wrb, WRB_SEQNO(wrb), WRB_PKTLEN(wrb), WRB_SENT(wrb));
        }
    }

    /* Check for a loss of connection */

    else if ((flags & (TCP_CLOSE | TCP_ABORT | TCP_TIMEDOUT)) != 0)
    {
        nllvdbg("Lost connection: %04x\n", flags);

        /* Report not connected */

        net_lostconnection(psock, flags);

        /* Free write buffers and terminate polling */

        psock_lost_connection(psock, conn);
        return flags;
    }

    /* Check if we are being asked to retransmit data */

    else if ((flags & TCP_REXMIT) != 0)
    {
        FAR struct tcp_wrbuffer_s *wrb;
        FAR sq_entry_t *entry;

        nllvdbg("REXMIT: %04x\n", flags);

        /* If there is a partially sent write buffer at the head of the
         * write_q?  Has anything been sent from that write buffer?
         */

        wrb = (FAR struct tcp_wrbuffer_s *)sq_peek(&conn->write_q);
        nllvdbg("REXMIT: wrb=%p sent=%u\n", wrb, wrb ? WRB_SENT(wrb) : 0);

        if (wrb != NULL && WRB_SENT(wrb) > 0)
        {
            FAR struct tcp_wrbuffer_s *tmp;
            uint16_t sent;

            /* Yes.. Reset the number of bytes sent sent from the write buffer */

            sent = WRB_SENT(wrb);
            if (conn->unacked > sent)
            {
                conn->unacked -= sent;
            }
            else
            {
                conn->unacked = 0;
            }

            if (conn->sent > sent)
            {
                conn->sent -= sent;
            }
            else
            {
                conn->sent = 0;
            }

            WRB_SENT(wrb) = 0;
            nllvdbg("REXMIT: wrb=%p sent=%u, conn unacked=%d sent=%d\n",
                    wrb, WRB_SENT(wrb), conn->unacked, conn->sent);

            /* Increment the retransmit count on this write buffer. */

            if (++WRB_NRTX(wrb) >= TCP_MAXRTX)
            {
                nlldbg("Expiring wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));

                /* The maximum retry count as been exhausted. Remove the write
                 * buffer at the head of the queue.
                 */

                tmp = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q);
                DEBUGASSERT(tmp == wrb);
                UNUSED(tmp);

                /* And return the write buffer to the free list */

                tcp_wrbuffer_release(wrb);

                /* NOTE expired is different from un-ACKed, it is designed to
                 * represent the number of segments that have been sent,
                 * retransmitted, and un-ACKed, if expired is not zero, the
                 * connection will be closed.
                 *
                 * field expired can only be updated at TCP_ESTABLISHED state
                 */

                conn->expired++;
            }
        }

        /* Move all segments that have been sent but not ACKed to the write
         * queue again note, the un-ACKed segments are put at the head of the
         * write_q so they can be resent as soon as possible.
         */

        while ((entry = sq_remlast(&conn->unacked_q)) != NULL)
        {
            wrb = (FAR struct tcp_wrbuffer_s*)entry;
            uint16_t sent;

            /* Reset the number of bytes sent sent from the write buffer */

            sent = WRB_SENT(wrb);
            if (conn->unacked > sent)
            {
                conn->unacked -= sent;
            }
            else
            {
                conn->unacked = 0;
            }

            if (conn->sent > sent)
            {
                conn->sent -= sent;
            }
            else
            {
                conn->sent = 0;
            }

            WRB_SENT(wrb) = 0;
            nllvdbg("REXMIT: wrb=%p sent=%u, conn unacked=%d sent=%d\n",
                    wrb, WRB_SENT(wrb), conn->unacked, conn->sent);

            /* Free any write buffers that have exceed the retry count */

            if (++WRB_NRTX(wrb) >= TCP_MAXRTX)
            {
                nlldbg("Expiring wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));

                /* Return the write buffer to the free list */

                tcp_wrbuffer_release(wrb);

                /* NOTE expired is different from un-ACKed, it is designed to
                 * represent the number of segments that have been sent,
                 * retransmitted, and un-ACKed, if expired is not zero, the
                 * connection will be closed.
                 *
                 * field expired can only be updated at TCP_ESTABLISHED state
                 */

                conn->expired++;
                continue;
            }
            else
            {
                /* Insert the write buffer into the write_q (in sequence
                 * number order).  The retransmission will occur below
                 * when the write buffer with the lowest sequenc number
                 * is pulled from the write_q again.
                 */

                nllvdbg("REXMIT: Moving wrb=%p nrtx=%u\n", wrb, WRB_NRTX(wrb));

                psock_insert_segment(wrb, &conn->write_q);
            }
        }
    }

    /* Check if the outgoing packet is available (it may have been claimed
     * by a sendto interrupt serving a different thread).
     */

    if (dev->d_sndlen > 0)
    {
        /* Another thread has beat us sending data, wait for the next poll */

        return flags;
    }

    /* We get here if (1) not all of the data has been ACKed, (2) we have been
     * asked to retransmit data, (3) the connection is still healthy, and (4)
     * the outgoing packet is available for our use.  In this case, we are
     * now free to send more data to receiver -- UNLESS the buffer contains
     * unprocessed incoming data.  In that event, we will have to wait for the
     * next polling cycle.
     */

    if ((conn->tcpstateflags & TCP_ESTABLISHED) &&
            (flags & (TCP_POLL | TCP_REXMIT)) &&
            !(sq_empty(&conn->write_q)))
    {
        /* Check if the destination IP address is in the ARP table.  If not,
         * then the send won't actually make it out... it will be replaced with
         * an ARP request.
         *
         * NOTE 1: This could be an expensive check if there are a lot of
         * entries in the ARP table.
         *
         * NOTE 2: If we are actually harvesting IP addresses on incoming IP
         * packets, then this check should not be necessary; the MAC mapping
         * should already be in the ARP table in many cases.
         *
         * NOTE 3: If CONFIG_NET_ARP_SEND then we can be assured that the IP
         * address mapping is already in the ARP table.
         */

#if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN) && \
    !defined(CONFIG_NET_ARP_SEND)
        if (arp_find(conn->ripaddr) != NULL)
#endif
        {
            FAR struct tcp_wrbuffer_s *wrb;
            size_t sndlen;

            /* Peek at the head of the write queue (but don't remove anything
             * from the write queue yet).  We know from the above test that
             * the write_q is not empty.
             */

            wrb = (FAR struct tcp_wrbuffer_s *)sq_peek(&conn->write_q);
            DEBUGASSERT(wrb);

            /* Get the amount of data that we can send in the next packet.
             * We will send either the remaining data in the buffer I/O
             * buffer chain, or as much as will fit given the MSS and current
             * window size.
             */

            sndlen = WRB_PKTLEN(wrb) - WRB_SENT(wrb);
            if (sndlen > tcp_mss(conn))
            {
                sndlen = tcp_mss(conn);
            }

            if (sndlen > conn->winsize)
            {
                sndlen = conn->winsize;
            }

            nllvdbg("SEND: wrb=%p pktlen=%u sent=%u sndlen=%u\n",
                    wrb, WRB_PKTLEN(wrb), WRB_SENT(wrb), sndlen);

            /* Set the sequence number for this segment.  If we are
             * retransmitting, then the sequence number will already
             * be set for this write buffer.
             */

            if (WRB_SEQNO(wrb) == (unsigned)-1)
            {
                WRB_SEQNO(wrb) = conn->isn + conn->sent;
            }

            /* The TCP stack updates sndseq on receipt of ACK *before*
             * this function is called. In that case sndseq will point
             * to the next unacknowledged byte (which might have already
             * been sent). We will overwrite the value of sndseq here
             * before the packet is sent.
             */

            tcp_setsequence(conn->sndseq, WRB_SEQNO(wrb) + WRB_SENT(wrb));

            /* Then set-up to send that amount of data with the offset
             * corresponding to the amount of data already sent. (this
             * won't actually happen until the polling cycle completes).
             */

            devif_iob_send(dev, WRB_IOB(wrb), sndlen, WRB_SENT(wrb));

            /* Remember how much data we send out now so that we know
             * when everything has been acknowledged.  Just increment
             * the amount of data sent. This will be needed in sequence
             * number calculations.
             */

            conn->unacked += sndlen;
            conn->sent    += sndlen;

            nllvdbg("SEND: wrb=%p nrtx=%u unacked=%u sent=%u\n",
                    wrb, WRB_NRTX(wrb), conn->unacked, conn->sent);

            /* Increment the count of bytes sent from this write buffer */

            WRB_SENT(wrb) += sndlen;

            nllvdbg("SEND: wrb=%p sent=%u pktlen=%u\n",
                    wrb, WRB_SENT(wrb), WRB_PKTLEN(wrb));

            /* Remove the write buffer from the write queue if the
             * last of the data has been sent from the buffer.
             */

            DEBUGASSERT(WRB_SENT(wrb) <= WRB_PKTLEN(wrb));
            if (WRB_SENT(wrb) >= WRB_PKTLEN(wrb))
            {
                FAR struct tcp_wrbuffer_s *tmp;

                nllvdbg("SEND: wrb=%p Move to unacked_q\n", wrb);

                tmp = (FAR struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q);
                DEBUGASSERT(tmp == wrb);
                UNUSED(tmp);

                /* Put the I/O buffer chain in the un-acked queue; the
                 * segment is waiting for ACK again
                 */

                psock_insert_segment(wrb, &conn->unacked_q);
            }

            /* Only one data can be sent by low level driver at once,
             * tell the caller stop polling the other connection.
             */

            flags &= ~TCP_POLL;
        }
    }

    /* Continue waiting */

    return flags;
}