Пример #1
0
void slirp_socket_recv(int addr_low_byte, int guest_port, const uint8_t *buf,
        int size)
{
    int ret;
    struct socket *so = slirp_find_ctl_socket(addr_low_byte, guest_port);
   
    if (!so)
        return;

    ret = soreadbuf(so, (const char *)buf, size);

    if (ret > 0)
        tcp_output(sototcpcb(so));
}
/*
 * remque and free a socket, clobber cache
 */
void
sofree(PNATState pData, struct socket *so)
{
    LogFlowFunc(("ENTER:%R[natsock]\n", so));
    /*
     * We should not remove socket when polling routine do the polling
     * instead we mark it for deletion.
     */
    if (so->fUnderPolling)
    {
        so->fShouldBeRemoved = 1;
        LogFlowFunc(("LEAVE:%R[natsock] postponed deletion\n", so));
        return;
    }
    /**
     * Check that we don't freeng socket with tcbcb
     */
    Assert(!sototcpcb(so));
    /* udp checks */
    Assert(!so->so_timeout);
    Assert(!so->so_timeout_arg);
    if (so == tcp_last_so)
        tcp_last_so = &tcb;
    else if (so == udp_last_so)
        udp_last_so = &udb;

    /* check if mbuf haven't been already freed  */
    if (so->so_m != NULL)
    {
        m_freem(pData, so->so_m);
        so->so_m = NULL;
    }

    if (so->so_ohdr != NULL)
    {
        RTMemFree(so->so_ohdr);
        so->so_ohdr = NULL;
    }

    if (so->so_next && so->so_prev)
    {
        remque(pData, so);  /* crashes if so is not in a queue */
        NSOCK_DEC();
    }

    RTMemFree(so);
    LogFlowFuncLeave();
}
Пример #3
0
/*
 * Tcp protocol timeout routine called every 500 ms.
 * Updates the timers in all active tcb's and
 * causes finite state machine actions if timers expire.
 */
void
tcp_slowtimo()
{
	register struct socket *ip, *ipnxt;
	register struct tcpcb *tp;
	register int i;

	DEBUG_CALL("tcp_slowtimo");
	
	tcp_maxidle = TCPTV_KEEPCNT * tcp_keepintvl;
	/*
	 * Search through tcb's and update active timers.
	 */
	ip = tcb.so_next;
	if (ip == 0)
	   return;
	for (; ip != &tcb; ip = ipnxt) {
		ipnxt = ip->so_next;
		tp = sototcpcb(ip);
		if (tp == 0)
			continue;
		for (i = 0; i < TCPT_NTIMERS; i++) {
			if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
				tcp_timers(tp,i);
				if (ipnxt->so_prev != ip)
					goto tpgone;
			}
		}
		tp->t_idle++;
		if (tp->t_rtt)
		   tp->t_rtt++;
tpgone:
		;
	}
	tcp_iss += TCP_ISSINCR/PR_SLOWHZ;		/* increment iss */
#ifdef TCP_COMPAT_42
	if ((int)tcp_iss < 0)
		tcp_iss = 0;				/* XXX */
#endif
	tcp_now++;					/* for timestamps */
}
Пример #4
0
int soreadbuf(struct socket *so, const char *buf, int size)
{
    int n, nn, copy = size;
	struct sbuf *sb = &so->so_snd;
	struct iovec iov[2];

	DEBUG_CALL("soreadbuf");
	DEBUG_ARG("so = %lx", (long )so);

	/*
	 * No need to check if there's enough room to read.
	 * soread wouldn't have been called if there weren't
	 */
	if (sopreprbuf(so, iov, &n) < size)
        goto err;

    nn = MIN(iov[0].iov_len, copy);
    memcpy(iov[0].iov_base, buf, nn);

    copy -= nn;
    buf += nn;

    if (copy == 0)
        goto done;

    memcpy(iov[1].iov_base, buf, copy);

done:
    /* Update fields */
	sb->sb_cc += size;
	sb->sb_wptr += size;
	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_wptr -= sb->sb_datalen;
    return size;
err:

    sofcantrcvmore(so);
    tcp_sockclosed(sototcpcb(so));
    fprintf(stderr, "soreadbuf buffer to small");
    return -1;
}
Пример #5
0
/*
 * Get urgent data
 * 
 * When the socket is created, we set it SO_OOBINLINE,
 * so when OOB data arrives, we soread() it and everything
 * in the send buffer is sent as urgent data
 */
void sorecvoob(struct socket *so)
{
	struct tcpcb *tp = sototcpcb(so);

	DEBUG_CALL("sorecvoob");
	DEBUG_ARG("so = %p", so);
	
	/*
	 * We take a guess at how much urgent data has arrived.
	 * In most situations, when urgent data arrives, the next
	 * read() should get all the urgent data.  This guess will
	 * be wrong however if more data arrives just after the
	 * urgent data, or the read() doesn't return all the 
	 * urgent data.
	 */
	soread(so);
	tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
	tp->t_force = 1;
	tcp_output(tp);
	tp->t_force = 0;
}
Пример #6
0
void tcp_pulloutofband(struct socket *so, struct tcpiphdr *ti, struct mbuf *m)
{
	int cnt = ti->ti_urp - 1;
	
	while (cnt >= 0) {
		if (m->m_len > cnt) {
			char *cp = mtod(m, caddr_t) + cnt;
			struct tcpcb *tp = sototcpcb(so);

			tp->t_iobc = *cp;
			tp->t_oobflags |= TCPOOB_HAVEDATA;
			memcpy(sp, cp+1, (unsigned)(m->m_len - cnt - 1));
			m->m_len--;
			return;
		}
		cnt -= m->m_len;
		m = m->m_next; /* XXX WRONG! Fix it! */
		if (m == 0)
			break;
	}
	panic("tcp_pulloutofband");
}
Пример #7
0
/*
 * Tcp protocol timeout routine called every 500 ms.
 * Updates the timers in all active tcb's and
 * causes finite state machine actions if timers expire.
 */
void
tcp_slowtimo(Slirp *slirp)
{
	register struct socket *ip, *ipnxt;
	register struct tcpcb *tp;
	register int i;

	DEBUG_CALL("tcp_slowtimo");

	/*
	 * Search through tcb's and update active timers.
	 */
	ip = slirp->tcb.so_next;
        if (ip == NULL) {
            return;
        }
	for (; ip != &slirp->tcb; ip = ipnxt) {
		ipnxt = ip->so_next;
		tp = sototcpcb(ip);
                if (tp == NULL) {
                        continue;
                }
		for (i = 0; i < TCPT_NTIMERS; i++) {
			if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
				tcp_timers(tp,i);
				if (ipnxt->so_prev != ip)
					goto tpgone;
			}
		}
		tp->t_idle++;
		if (tp->t_rtt)
		   tp->t_rtt++;
tpgone:
		;
	}
	slirp->tcp_iss += TCP_ISSINCR/PR_SLOWHZ;	/* increment iss */
	slirp->tcp_now++;				/* for timestamps */
}
Пример #8
0
/*
 * Pull out of band byte out of a segment so
 * it doesn't appear in the user's data queue.
 * It is still reflected in the segment length for
 * sequencing purposes.
 */
void
tcp_pulloutofband(struct usn_socket *so, struct tcpiphdr *ti, usn_mbuf_t *m)
{
	int cnt = ti->ti_urp - 1;
	
	while (cnt >= 0) {
		if (m->mlen > cnt) {
			char *cp = mtod(m, caddr_t) + cnt;
			struct tcpcb *tp = sototcpcb(so);

			tp->t_iobc = *cp;
			tp->t_oobflags |= TCPOOB_HAVEDATA;
			bcopy(cp+1, cp, (unsigned)(m->mlen - cnt - 1));
			m->mlen--;
			return;
		}
		cnt -= m->mlen;
		m = m->next;
		if (m == 0)
			break;
	}
	DEBUG("panic: tcp_pulloutofband");
}
Пример #9
0
void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
{
    struct socket *so, *so_next;
    int ret;

    global_readfds = readfds;
    global_writefds = writefds;
    global_xfds = xfds;

	/* Update time */
	updtime();
	
	/*
	 * See if anything has timed out 
	 */
	if (link_up) {
		if (time_fasttimo && ((curtime - time_fasttimo) >= FAST_TIMO)) {
			tcp_fasttimo();
			time_fasttimo = 0;
		}
		if (do_slowtimo && ((curtime - last_slowtimo) >= SLOW_TIMO)) {
			ip_slowtimo();
			tcp_slowtimo();
			last_slowtimo = curtime;
		}
	}
	
	/*
	 * Check sockets
	 */
	if (link_up) {
		/*
		 * Check TCP sockets
		 */
		for (so = tcb.so_next; so != &tcb; so = so_next) {
			so_next = so->so_next;
			
			/*
			 * FD_ISSET is meaningless on these sockets
			 * (and they can crash the program)
			 */
			if (so->so_state & SS_NOFDREF || so->s == -1)
			   continue;
			
			/*
			 * Check for URG data
			 * This will soread as well, so no need to
			 * test for readfds below if this succeeds
			 */
			if (FD_ISSET(so->s, xfds))
			   sorecvoob(so);
			/*
			 * Check sockets for reading
			 */
			else if (FD_ISSET(so->s, readfds)) {
				/*
				 * Check for incoming connections
				 */
				if (so->so_state & SS_FACCEPTCONN) {
					tcp_connect(so);
					continue;
				} /* else */
				ret = soread(so);
				
				/* Output it if we read something */
				if (ret > 0)
				   tcp_output(sototcpcb(so));
			}
			
			/*
			 * Check sockets for writing
			 */
			if (FD_ISSET(so->s, writefds)) {
			  /*
			   * Check for non-blocking, still-connecting sockets
			   */
			  if (so->so_state & SS_ISFCONNECTING) {
			    /* Connected */
			    so->so_state &= ~SS_ISFCONNECTING;
			    
			    ret = send(so->s, &ret, 0, 0);
			    if (ret < 0) {
			      /* XXXXX Must fix, zero bytes is a NOP */
			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
				  errno == EINPROGRESS || errno == ENOTCONN)
				continue;
			      
			      /* else failed */
			      so->so_state = SS_NOFDREF;
			    }
			    /* else so->so_state &= ~SS_ISFCONNECTING; */
			    
			    /*
			     * Continue tcp_input
			     */
			    tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
			    /* continue; */
			  } else
			    ret = sowrite(so);
			  /*
			   * XXXXX If we wrote something (a lot), there 
			   * could be a need for a window update.
			   * In the worst case, the remote will send
			   * a window probe to get things going again
			   */
			}
			
			/*
			 * Probe a still-connecting, non-blocking socket
			 * to check if it's still alive
	 	 	 */
#ifdef PROBE_CONN
			if (so->so_state & SS_ISFCONNECTING) {
			  ret = recv(so->s, (char *)&ret, 0,0);
			  
			  if (ret < 0) {
			    /* XXX */
			    if (errno == EAGAIN || errno == EWOULDBLOCK ||
				errno == EINPROGRESS || errno == ENOTCONN)
			      continue; /* Still connecting, continue */
			    
			    /* else failed */
			    so->so_state = SS_NOFDREF;
			    
			    /* tcp_input will take care of it */
			  } else {
			    ret = send(so->s, &ret, 0,0);
			    if (ret < 0) {
			      /* XXX */
			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
				  errno == EINPROGRESS || errno == ENOTCONN)
				continue;
			      /* else failed */
			      so->so_state = SS_NOFDREF;
			    } else
			      so->so_state &= ~SS_ISFCONNECTING;
			    
			  }
			  tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
			} /* SS_ISFCONNECTING */
#endif
		}
		
		/*
		 * Now UDP sockets.
		 * Incoming packets are sent straight away, they're not buffered.
		 * Incoming UDP data isn't buffered either.
		 */
		for (so = udb.so_next; so != &udb; so = so_next) {
			so_next = so->so_next;
			
			if (so->s != -1 && FD_ISSET(so->s, readfds)) {
                            sorecvfrom(so);
                        }
		}
	}
	
	/*
	 * See if we can start outputting
	 */
	if (if_queued && link_up)
	   if_start();

	/* clear global file descriptor sets.
	 * these reside on the stack in vl.c
	 * so they're unusable if we're not in
	 * slirp_select_fill or slirp_select_poll.
	 */
	 global_readfds = NULL;
	 global_writefds = NULL;
	 global_xfds = NULL;
}
Пример #10
0
/*
 * Read from so's socket into sb_snd, updating all relevant sbuf fields
 * NOTE: This will only be called if it is select()ed for reading, so
 * a read() of 0 (or less) means it's disconnected
 */
int
soread(PNATState pData, struct socket *so)
{
    int n, nn, lss, total;
    struct sbuf *sb = &so->so_snd;
    u_int len = sb->sb_datalen - sb->sb_cc;
    struct iovec iov[2];
    int mss = so->so_tcpcb->t_maxseg;
    int sockerr;

    STAM_PROFILE_START(&pData->StatIOread, a);
    STAM_COUNTER_RESET(&pData->StatIORead_in_1);
    STAM_COUNTER_RESET(&pData->StatIORead_in_2);

    QSOCKET_LOCK(tcb);
    SOCKET_LOCK(so);
    QSOCKET_UNLOCK(tcb);

    LogFlow(("soread: so = %R[natsock]\n", so));
    Log2(("%s: so = %R[natsock] so->so_snd = %R[sbuf]\n", RT_GCC_EXTENSION __PRETTY_FUNCTION__, so, sb));

    /*
     * No need to check if there's enough room to read.
     * soread wouldn't have been called if there weren't
     */

    len = sb->sb_datalen - sb->sb_cc;

    iov[0].iov_base = sb->sb_wptr;
    iov[1].iov_base = 0;
    iov[1].iov_len  = 0;
    if (sb->sb_wptr < sb->sb_rptr)
    {
        iov[0].iov_len = sb->sb_rptr - sb->sb_wptr;
        /* Should never succeed, but... */
        if (iov[0].iov_len > len)
            iov[0].iov_len = len;
        if (iov[0].iov_len > mss)
            iov[0].iov_len -= iov[0].iov_len%mss;
        n = 1;
    }
    else
    {
        iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_wptr;
        /* Should never succeed, but... */
        if (iov[0].iov_len > len)
            iov[0].iov_len = len;
        len -= iov[0].iov_len;
        if (len)
        {
            iov[1].iov_base = sb->sb_data;
            iov[1].iov_len = sb->sb_rptr - sb->sb_data;
            if (iov[1].iov_len > len)
                iov[1].iov_len = len;
            total = iov[0].iov_len + iov[1].iov_len;
            if (total > mss)
            {
                lss = total % mss;
                if (iov[1].iov_len > lss)
                {
                    iov[1].iov_len -= lss;
                    n = 2;
                }
                else
                {
                    lss -= iov[1].iov_len;
                    iov[0].iov_len -= lss;
                    n = 1;
                }
            }
            else
                n = 2;
        }
        else
        {
            if (iov[0].iov_len > mss)
                iov[0].iov_len -= iov[0].iov_len%mss;
            n = 1;
        }
    }

#ifdef HAVE_READV
    nn = readv(so->s, (struct iovec *)iov, n);
#else
    nn = recv(so->s, iov[0].iov_base, iov[0].iov_len, (so->so_tcpcb->t_force? MSG_OOB:0));
#endif
    if (nn < 0)
        sockerr = errno; /* save it, as it may be clobbered by logging */
    else
        sockerr = 0;

    Log2(("%s: read(1) nn = %d bytes\n", RT_GCC_EXTENSION __PRETTY_FUNCTION__, nn));
    Log2(("%s: so = %R[natsock] so->so_snd = %R[sbuf]\n", RT_GCC_EXTENSION __PRETTY_FUNCTION__, so, sb));
    if (nn <= 0)
    {
#ifdef RT_OS_WINDOWS
        /*
         * Windows reports ESHUTDOWN after SHUT_RD (SD_RECEIVE)
         * instead of just returning EOF indication.
         */
        if (nn < 0 && sockerr == ESHUTDOWN)
        {
            nn = 0;
            sockerr = 0;
        }
#endif

        if (nn == 0) /* XXX: should this be inside #if defined(RT_OS_WINDOWS)? */
        {
            /*
             * Special case for WSAEnumNetworkEvents: If we receive 0 bytes that
             * _could_ mean that the connection is closed. But we will receive an
             * FD_CLOSE event later if the connection was _really_ closed. With
             * www.youtube.com I see this very often. Closing the socket too early
             * would be dangerous.
             */
            int status;
            unsigned long pending = 0;
            status = ioctlsocket(so->s, FIONREAD, &pending);
            if (status < 0)
                Log(("NAT:%s: error in WSAIoctl: %d\n", RT_GCC_EXTENSION __PRETTY_FUNCTION__, errno));
            if (pending != 0)
            {
                SOCKET_UNLOCK(so);
                STAM_PROFILE_STOP(&pData->StatIOread, a);
                return 0;
            }
        }

        if (   nn < 0
            && soIgnorableErrorCode(sockerr))
        {
            SOCKET_UNLOCK(so);
            STAM_PROFILE_STOP(&pData->StatIOread, a);
            return 0;
        }
        else
        {
            int fUninitializedTemplate = 0;
            int shuterr;

            fUninitializedTemplate = RT_BOOL((   sototcpcb(so)
                                              && (  sototcpcb(so)->t_template.ti_src.s_addr == INADDR_ANY
                                                 || sototcpcb(so)->t_template.ti_dst.s_addr == INADDR_ANY)));
            /* nn == 0 means peer has performed an orderly shutdown */
            Log2(("%s: disconnected, nn = %d, errno = %d (%s)\n",
                  RT_GCC_EXTENSION __PRETTY_FUNCTION__, nn, sockerr, strerror(sockerr)));

            shuterr = sofcantrcvmore(so);
            if (!sockerr && !shuterr && !fUninitializedTemplate)
                tcp_sockclosed(pData, sototcpcb(so));
            else
            {
                LogRel2(("NAT: sockerr %d, shuterr %d - %R[natsock]\n", sockerr, shuterr, so));
                tcp_drop(pData, sototcpcb(so), sockerr);
            }
            SOCKET_UNLOCK(so);
            STAM_PROFILE_STOP(&pData->StatIOread, a);
            return -1;
        }
    }
    STAM_STATS(
        if (n == 1)
        {
            STAM_COUNTER_INC(&pData->StatIORead_in_1);
            STAM_COUNTER_ADD(&pData->StatIORead_in_1_bytes, nn);
        }
        else
        {
            STAM_COUNTER_INC(&pData->StatIORead_in_2);
            STAM_COUNTER_ADD(&pData->StatIORead_in_2_1st_bytes, nn);
        }
    );
Пример #11
0
__private_extern__ void
inpcb_get_ports_used(uint32_t ifindex, int protocol, uint32_t flags,
    bitstr_t *bitfield, struct inpcbinfo *pcbinfo)
{
	struct inpcb *inp;
	struct socket *so;
	inp_gen_t gencnt;
	bool iswildcard, wildcardok, nowakeok;
	bool recvanyifonly, extbgidleok;
	bool activeonly;

	wildcardok = ((flags & INPCB_GET_PORTS_USED_WILDCARDOK) != 0);
	nowakeok = ((flags & INPCB_GET_PORTS_USED_NOWAKEUPOK) != 0);
	recvanyifonly = ((flags & INPCB_GET_PORTS_USED_RECVANYIFONLY) != 0);
	extbgidleok = ((flags & INPCB_GET_PORTS_USED_EXTBGIDLEONLY) != 0);
	activeonly = ((flags & INPCB_GET_PORTS_USED_ACTIVEONLY) != 0);

	lck_rw_lock_shared(pcbinfo->ipi_lock);
	gencnt = pcbinfo->ipi_gencnt;

	for (inp = LIST_FIRST(pcbinfo->ipi_listhead); inp;
	    inp = LIST_NEXT(inp, inp_list)) {
		uint16_t port;

		if (inp->inp_gencnt > gencnt ||
		    inp->inp_state == INPCB_STATE_DEAD ||
		    inp->inp_wantcnt == WNT_STOPUSING)
			continue;

		if ((so = inp->inp_socket) == NULL ||
		    (so->so_state & SS_DEFUNCT) ||
		    (so->so_state & SS_ISDISCONNECTED))
			continue;

		if (!(protocol == PF_UNSPEC ||
		    (protocol == PF_INET && (inp->inp_vflag & INP_IPV4)) ||
		    (protocol == PF_INET6 && (inp->inp_vflag & INP_IPV6))))
			continue;

		iswildcard = (((inp->inp_vflag & INP_IPV4) &&
		    inp->inp_laddr.s_addr == INADDR_ANY) ||
		    ((inp->inp_vflag & INP_IPV6) &&
		    IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)));

		if (!wildcardok && iswildcard)
			continue;

		if ((so->so_options & SO_NOWAKEFROMSLEEP) &&
			!nowakeok)
			continue;

		if (!(inp->inp_flags & INP_RECV_ANYIF) &&
			recvanyifonly)
			continue;

		if (!(so->so_flags1 & SOF1_EXTEND_BK_IDLE_WANTED) &&
			extbgidleok)
			continue;

		if (!iswildcard &&
		    !(ifindex == 0 || inp->inp_last_outifp == NULL ||
		    ifindex == inp->inp_last_outifp->if_index))
			continue;

		if (SOCK_PROTO(inp->inp_socket) == IPPROTO_UDP &&
		    so->so_state & SS_CANTRCVMORE)
			continue;

		if (SOCK_PROTO(inp->inp_socket) == IPPROTO_TCP) {
			struct  tcpcb *tp = sototcpcb(inp->inp_socket);

			/*
			 * Workaround race where inp_ppcb is NULL during
			 * socket initialization
			 */
			if (tp == NULL)
				continue;

			switch (tp->t_state) {
				case TCPS_CLOSED:
					continue;
					/* NOT REACHED */
				case TCPS_LISTEN:
				case TCPS_SYN_SENT:
				case TCPS_SYN_RECEIVED:
				case TCPS_ESTABLISHED:
				case TCPS_FIN_WAIT_1:
					/*
					 * Note: FIN_WAIT_1 is an active state
					 * because we need our FIN to be
					 * acknowledged
					 */
					break;
				case TCPS_CLOSE_WAIT:
				case TCPS_CLOSING:
				case TCPS_LAST_ACK:
				case TCPS_FIN_WAIT_2:
					/*
					 * In the closing states, the connection
					 * is not idle when there is outgoing
					 * data having to be acknowledged
					 */
					if (activeonly && so->so_snd.sb_cc == 0)
						continue;
					break;
				case TCPS_TIME_WAIT:
					continue;
					/* NOT REACHED */
			}
		}
		/*
		 * Final safeguard to exclude unspecified local port
		 */
		port = ntohs(inp->inp_lport);
		if (port == 0)
			continue;
		bit_set(bitfield, port);
	}
	lck_rw_done(pcbinfo->ipi_lock);
}
Пример #12
0
int
tcp_usrreq(struct socket * so, 
   struct mbuf *  m,
   struct mbuf *  nam)
{
   struct inpcb * inp;
   struct tcpcb * tp;
   int   error =  0;
   int   req;

#ifdef DO_TCPTRACE
   int   ostate;
#endif

   req = so->so_req;    /* get request from socket struct */
   inp = sotoinpcb(so);
   /*
    * When a TCP is attached to a socket, then there will be
    * a (struct inpcb) pointed at by the socket, and this
    * structure will point at a subsidary (struct tcpcb).
    */
   if (inp == 0 && req != PRU_ATTACH) 
   {
      return (EINVAL);
   }

   if (inp)
      tp = intotcpcb(inp);
   else  /* inp and tp not set, make sure this is OK: */
   { 
      if (req == PRU_ATTACH)
         tp = NULL;  /* stifle compiler warnings about using unassigned tp*/
      else
      {
         dtrap(); /* programming error? */
         return EINVAL;
      }
   }

   switch (req) 
   {
   /*
    * TCP attaches to socket via PRU_ATTACH, reserving space,
    * and an internet control block.
    */
   case PRU_ATTACH:
      if (inp) 
      {
         error = EISCONN;
         break;
      }
      error = tcp_attach(so);
      if (error)
         break;
      if ((so->so_options & SO_LINGER) && so->so_linger == 0)
         so->so_linger = TCP_LINGERTIME;
#ifdef   DO_TCPTRACE
      SETTP(tp, sototcpcb(so));
#endif
      break;

   /*
    * PRU_DETACH detaches the TCP protocol from the socket.
    * If the protocol state is non-embryonic, then can't
    * do this directly: have to initiate a PRU_DISCONNECT,
    * which may finish later; embryonic TCB's can just
    * be discarded here.
    */
   case PRU_DETACH:
      if (tp->t_state > TCPS_LISTEN)
         SETTP(tp, tcp_disconnect(tp));
      else
         SETTP(tp, tcp_close(tp));
      break;

   /*
    * Give the socket an address.
    */
   case PRU_BIND:

      /* bind is quite different for IPv4 and v6, so we use two 
       * seperate pcbbind routines. so_domain was checked for 
       * validity way up in t_bind()
       */
#ifdef IP_V4
      if(inp->inp_socket->so_domain == AF_INET)
      {
         error = in_pcbbind(inp, nam);
         break;
      }
#endif /* IP_V4 */
#ifdef IP_V6
      if(inp->inp_socket->so_domain == AF_INET6)
      {
         error = ip6_pcbbind(inp, nam);
         break;
      }
#endif /* IP_V6 */
      dtrap();    /* not v4 or v6? */
      error = EINVAL;
      break;
   /*
    * Prepare to accept connections.
    */
   case PRU_LISTEN:
      if (inp->inp_lport == 0)
         error = in_pcbbind(inp, (struct mbuf *)0);
      if (error == 0)
         tp->t_state = TCPS_LISTEN;
      break;

   /*
    * Initiate connection to peer.
    * Create a template for use in transmissions on this connection.
    * Enter SYN_SENT state, and mark socket as connecting.
    * Start keep-alive timer, and seed output sequence space.
    * Send initial segment on connection.
    */
   case PRU_CONNECT:
      if (inp->inp_lport == 0) 
      {

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      error = in_pcbbind(inp, (struct mbuf *)0);
#else    /* dual mode */
      if(so->so_domain == AF_INET)
         error = in_pcbbind(inp, (struct mbuf *)0);
      else
         error = ip6_pcbbind(inp, (struct mbuf *)0);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
      error = ip6_pcbbind(inp, (struct mbuf *)0);
#endif   /* end v6 only */

         if (error)
            break;
      }

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      error = in_pcbconnect(inp, nam);
#else    /* dual mode */
      if(so->so_domain == AF_INET)
         error = in_pcbconnect(inp, nam);
      else
         error = ip6_pcbconnect(inp, nam);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
      error = ip6_pcbconnect(inp, nam);
#endif   /* end v6 only */

      if (error)
         break;
      tp->t_template = tcp_template(tp);
      if (tp->t_template == 0) 
      {

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
         in_pcbdisconnect(inp);
#else    /* dual mode */
         if(so->so_domain == AF_INET)
            in_pcbdisconnect(inp);
         else
            ip6_pcbdisconnect(inp);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
         ip6_pcbdisconnect(inp);
#endif   /* end v6 only */

         error = ENOBUFS;
         break;
      }

      soisconnecting(so);
      tcpstat.tcps_connattempt++;
      tp->t_state = TCPS_SYN_SENT;
      tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
      tp->iss = tcp_iss; 
      tcp_iss += (tcp_seq)(TCP_ISSINCR/2);
      tcp_sendseqinit(tp);
      error = tcp_output(tp);
      if (!error)
         TCP_MIB_INC(tcpActiveOpens);     /* keep MIB stats */
      break;

   /*
    * Create a TCP connection between two sockets.
    */
   case PRU_CONNECT2:
      error = EOPNOTSUPP;
      break;

   /*
    * Initiate disconnect from peer.
    * If connection never passed embryonic stage, just drop;
    * else if don't need to let data drain, then can just drop anyways,
    * else have to begin TCP shutdown process: mark socket disconnecting,
    * drain unread data, state switch to reflect user close, and
    * send segment (e.g. FIN) to peer.  Socket will be really disconnected
    * when peer sends FIN and acks ours.
    *
    * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
    */
   case PRU_DISCONNECT:
      SETTP(tp, tcp_disconnect(tp));
      break;

   /*
    * Accept a connection.  Essentially all the work is
    * done at higher levels; just return the address
    * of the peer, storing through addr.
    */
   case PRU_ACCEPT: 
   {
         struct sockaddr_in * sin   =  mtod(nam,   struct sockaddr_in *);
#ifdef IP_V6
         struct sockaddr_in6 * sin6 = mtod(nam,   struct sockaddr_in6 *);
#endif

#ifdef IP_V6
         if (so->so_domain == AF_INET6)
         {
            nam->m_len = sizeof (struct sockaddr_in6);
            sin6->sin6_port = inp->inp_fport;
            sin6->sin6_family = AF_INET6;
            IP6CPY(&sin6->sin6_addr, &inp->ip6_faddr);
         }
#endif

#ifdef IP_V4
         if (so->so_domain == AF_INET)
         {
            nam->m_len = sizeof (struct sockaddr_in);
            sin->sin_family = AF_INET;
            sin->sin_port = inp->inp_fport;
            sin->sin_addr = inp->inp_faddr;
         }
#endif
         if ( !(so->so_domain == AF_INET) &&
              !(so->so_domain == AF_INET6)
             )
         {
            dprintf("*** PRU_ACCEPT bad domain = %d\n", so->so_domain);
            dtrap();
         } 
         TCP_MIB_INC(tcpPassiveOpens);    /* keep MIB stats */
         break;
      }

   /*
    * Mark the connection as being incapable of further output.
    */
   case PRU_SHUTDOWN:
      socantsendmore(so);
      tp = tcp_usrclosed(tp);
      if (tp)
         error = tcp_output(tp);
      break;

   /*
    * After a receive, possibly send window update to peer.
    */
   case PRU_RCVD:
      (void) tcp_output(tp);
      break;

   /*
    * Do a send by putting data in output queue and updating urgent
    * marker if URG set.  Possibly send more data.
    */
   case PRU_SEND:
      if (so->so_pcb == NULL)
      {                    /* Return EPIPE error if socket is not connected */
         error = EPIPE;
         break;
      }
      sbappend(&so->so_snd, m);
      error = tcp_output(tp);
      if (error == ENOBUFS)
         sbdropend(&so->so_snd,m);  /* Remove data from socket buffer */
      break;

   /*
    * Abort the TCP.
    */
   case PRU_ABORT:
      SETTP(tp, tcp_drop(tp, ECONNABORTED));
      break;

   case PRU_SENSE:
      /*      ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; */
      dtrap();    /* does this ever happen? */
      return (0);

   case PRU_RCVOOB:
      if ((so->so_oobmark == 0 &&
          (so->so_state & SS_RCVATMARK) == 0) ||
#ifdef SO_OOBINLINE
       so->so_options & SO_OOBINLINE ||
#endif
       tp->t_oobflags & TCPOOB_HADDATA) 
       {
         error = EINVAL;
         break;
      }
      if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) 
      {
         error = EWOULDBLOCK;
         break;
      }
      m->m_len = 1;
      *mtod(m, char *) = tp->t_iobc;
      if ((MBUF2LONG(nam) & MSG_PEEK) == 0)
         tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
      break;

   case PRU_SENDOOB:
      if (so->so_pcb == NULL)
      {                    /* Return EPIPE error if socket is not connected */
         error = EPIPE;
         break;
      }
      if (sbspace(&so->so_snd) == 0) 
      {
         m_freem(m);
         error = ENOBUFS;
         break;
      }
      /*
       * According to RFC961 (Assigned Protocols),
       * the urgent pointer points to the last octet
       * of urgent data.  We continue, however,
       * to consider it to indicate the first octet
       * of data past the urgent section.
       * Otherwise, snd_up should be one lower.
       */
      sbappend(&so->so_snd, m);
      tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
      tp->t_force = 1;
      error = tcp_output(tp);
      if (error == ENOBUFS)
         sbdropend(&so->so_snd,m);  /* Remove data from socket buffer */
      tp->t_force = 0;
      break;

   case PRU_SOCKADDR:

   /* sockaddr and peeraddr have to switch based on IP type */
#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      in_setsockaddr(inp, nam);
#else /* dual mode */
      if(so->so_domain == AF_INET6)
         ip6_setsockaddr(inp, nam);
      else
         in_setsockaddr(inp, nam);
#endif   /* dual mode */
#else    /* IP_V6 */
         ip6_setsockaddr(inp, nam);
#endif
      break;         

   case PRU_PEERADDR:
#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      in_setpeeraddr(inp, nam);
#else /* dual mode */
      if(so->so_domain == AF_INET6)
         ip6_setpeeraddr(inp, nam);
      else
         in_setpeeraddr(inp, nam);
#endif   /* dual mode */
#else    /* IP_V6 */
         ip6_setpeeraddr(inp, nam);
#endif
      break;

   case PRU_SLOWTIMO:
      SETTP(tp, tcp_timers(tp, (int)MBUF2LONG(nam)));
#ifdef DO_TCPTRACE
      req |= (long)nam << 8;        /* for debug's sake */
#endif
      break;

      default:
      panic("tcp_usrreq");
   }
#ifdef DO_TCPTRACE
   if (tp && (so->so_options & SO_DEBUG))
      tcp_trace("usrreq: state: %d, tcpcb: %x, req: %d",
    ostate, tp, req);
#endif
   return (error);
}
Пример #13
0
/*
 * Read from so's socket into sb_snd, updating all relevant sbuf fields
 * NOTE: This will only be called if it is select()ed for reading, so
 * a read() of 0 (or less) means it's disconnected
 */
int
soread(struct socket *so)
{
	int n, nn, lss, total;
	struct sbuf *sb = &so->so_snd;
	int len = sb->sb_datalen - sb->sb_cc;
	struct iovec iov[2];
	int mss = so->so_tcpcb->t_maxseg;

	DEBUG_CALL("soread");
	DEBUG_ARG("so = %lx", (long )so);

	/*
	 * No need to check if there's enough room to read.
	 * soread wouldn't have been called if there weren't
	 */

	len = sb->sb_datalen - sb->sb_cc;

	iov[0].iov_base = sb->sb_wptr;
	if (sb->sb_wptr < sb->sb_rptr) {
		iov[0].iov_len = sb->sb_rptr - sb->sb_wptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len)
		   iov[0].iov_len = len;
		if (iov[0].iov_len > mss)
		   iov[0].iov_len -= iov[0].iov_len%mss;
		n = 1;
	} else {
		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_wptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		len -= iov[0].iov_len;
		if (len) {
			iov[1].iov_base = sb->sb_data;
			iov[1].iov_len = sb->sb_rptr - sb->sb_data;
			if(iov[1].iov_len > len)
			   iov[1].iov_len = len;
			total = iov[0].iov_len + iov[1].iov_len;
			if (total > mss) {
				lss = total%mss;
				if (iov[1].iov_len > lss) {
					iov[1].iov_len -= lss;
					n = 2;
				} else {
					lss -= iov[1].iov_len;
					iov[0].iov_len -= lss;
					n = 1;
				}
			} else
				n = 2;
		} else {
			if (iov[0].iov_len > mss)
			   iov[0].iov_len -= iov[0].iov_len%mss;
			n = 1;
		}
	}

#ifdef HAVE_READV
	nn = readv(so->s, (struct iovec *)iov, n);
	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#else
	nn = recv(so->s, iov[0].iov_base, iov[0].iov_len,0);
#endif
	if (nn <= 0) {
		if (nn < 0 && (errno == EINTR || errno == EAGAIN))
			return 0;
		else {
			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));
			sofcantrcvmore(so);
			tcp_sockclosed(sototcpcb(so));
			return -1;
		}
	}

#ifndef HAVE_READV
	/*
	 * If there was no error, try and read the second time round
	 * We read again if n = 2 (ie, there's another part of the buffer)
	 * and we read as much as we could in the first read
	 * We don't test for <= 0 this time, because there legitimately
	 * might not be any more data (since the socket is non-blocking),
	 * a close will be detected on next iteration.
	 * A return of -1 wont (shouldn't) happen, since it didn't happen above
	 */
	if (n == 2 && nn == iov[0].iov_len) {
            int ret;
            ret = recv(so->s, iov[1].iov_base, iov[1].iov_len,0);
            if (ret > 0)
                nn += ret;
        }

	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#endif

	/* Update fields */
	sb->sb_cc += nn;
	sb->sb_wptr += nn;
	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_wptr -= sb->sb_datalen;
	return nn;
}
Пример #14
0
void tcp_cleanup(void)
{
    while (tcb.so_next != &tcb) {
        tcp_close(sototcpcb(tcb.so_next));
    }
}
Пример #15
0
void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
{
    struct socket *so, *so_next;
    int ret;

    global_readfds = readfds;
    global_writefds = writefds;
    global_xfds = xfds;

	
	updtime();

	if (link_up) {
		if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
			tcp_fasttimo();
			time_fasttimo = 0;
		}
		if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
			ip_slowtimo();
			tcp_slowtimo();
			last_slowtimo = curtime;
		}
	}

	if (link_up) {
		for (so = tcb.so_next; so != &tcb; so = so_next) {
			so_next = so->so_next;

			if (so->so_state & SS_NOFDREF || so->s == -1)
			   continue;

            if ((so->so_state & SS_PROXIFIED) != 0)
                continue;

			if (FD_ISSET(so->s, xfds))
			   sorecvoob(so);
			else if (FD_ISSET(so->s, readfds)) {
				if (so->so_state & SS_FACCEPTCONN) {
					tcp_connect(so);
					continue;
				} 
				ret = soread(so);

				
				if (ret > 0)
				   tcp_output(sototcpcb(so));
			}

			if (FD_ISSET(so->s, writefds)) {
			  if (so->so_state & SS_ISFCONNECTING) {
			    
			    so->so_state &= ~SS_ISFCONNECTING;

			    ret = socket_send(so->s, (const void *)&ret, 0);
			    if (ret < 0) {
			      
			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
				  errno == EINPROGRESS || errno == ENOTCONN)
				continue;

			      
			      so->so_state = SS_NOFDREF;
			    }
			    

			    tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
			    
			  } else
			    ret = sowrite(so);
			}

#ifdef PROBE_CONN
			if (so->so_state & SS_ISFCONNECTING) {
			  ret = socket_recv(so->s, (char *)&ret, 0);

			  if (ret < 0) {
			    
			    if (errno == EAGAIN || errno == EWOULDBLOCK ||
				errno == EINPROGRESS || errno == ENOTCONN)
			      continue; 

			    
			    so->so_state = SS_NOFDREF;

			    
			  } else {
			    ret = socket_send(so->s, &ret, 0);
			    if (ret < 0) {
			      
			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
				  errno == EINPROGRESS || errno == ENOTCONN)
				continue;
			      
			      so->so_state = SS_NOFDREF;
			    } else
			      so->so_state &= ~SS_ISFCONNECTING;

			  }
			  tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
			} 
#endif
		}

		for (so = udb.so_next; so != &udb; so = so_next) {
			so_next = so->so_next;

            if ((so->so_state & SS_PROXIFIED) != 0)
                continue;

			if (so->s != -1 && FD_ISSET(so->s, readfds)) {
                            sorecvfrom(so);
                        }
		}
	}

    proxy_manager_poll(readfds, writefds, xfds);

	if (if_queued && link_up)
	   if_start();

	 global_readfds = NULL;
	 global_writefds = NULL;
	 global_xfds = NULL;
}
Пример #16
0
/*
 * TCP input routine, follows pages 65-76 of the
 * protocol specification dated September, 1981 very closely.
 */
void
tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
{
  	struct ip save_ip, *ip;
	register struct tcpiphdr *ti;
	caddr_t optp = NULL;
	int optlen = 0;
	int len, tlen, off;
        register struct tcpcb *tp = NULL;
	register int tiflags;
        struct socket *so = NULL;
	int todrop, acked, ourfinisacked, needoutput = 0;
	int iss = 0;
	u_long tiwin;
	int ret;
    struct ex_list *ex_ptr;
    Slirp *slirp;

	DEBUG_CALL("tcp_input");
	DEBUG_ARGS((dfd, " m = %8lx  iphlen = %2d  inso = %lx\n",
		    (long )m, iphlen, (long )inso ));

	/*
	 * If called with m == 0, then we're continuing the connect
	 */
	if (m == NULL) {
		so = inso;
		slirp = so->slirp;

		/* Re-set a few variables */
		tp = sototcpcb(so);
		m = so->so_m;
                so->so_m = NULL;
		ti = so->so_ti;
		tiwin = ti->ti_win;
		tiflags = ti->ti_flags;

		goto cont_conn;
	}
	slirp = m->slirp;

	/*
	 * Get IP and TCP header together in first mbuf.
	 * Note: IP leaves IP header in first mbuf.
	 */
	ti = mtod(m, struct tcpiphdr *);
	if (iphlen > sizeof(struct ip )) {
	  ip_stripoptions(m, (struct mbuf *)0);
	  iphlen=sizeof(struct ip );
	}
	/* XXX Check if too short */


	/*
	 * Save a copy of the IP header in case we want restore it
	 * for sending an ICMP error message in response.
	 */
	ip=mtod(m, struct ip *);
	save_ip = *ip;
	save_ip.ip_len+= iphlen;

	/*
	 * Checksum extended TCP header and data.
	 */
	tlen = ((struct ip *)ti)->ip_len;
        tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
        memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
	ti->ti_x1 = 0;
	ti->ti_len = htons((uint16_t)tlen);
	len = sizeof(struct ip ) + tlen;
	if(cksum(m, len)) {
	  goto drop;
	}

	/*
	 * Check that TCP offset makes sense,
	 * pull out TCP options and adjust length.		XXX
	 */
	off = ti->ti_off << 2;
	if (off < sizeof (struct tcphdr) || off > tlen) {
	  goto drop;
	}
	tlen -= off;
	ti->ti_len = tlen;
	if (off > sizeof (struct tcphdr)) {
	  optlen = off - sizeof (struct tcphdr);
	  optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr);
	}
	tiflags = ti->ti_flags;

	/*
	 * Convert TCP protocol specific fields to host format.
	 */
	NTOHL(ti->ti_seq);
	NTOHL(ti->ti_ack);
	NTOHS(ti->ti_win);
	NTOHS(ti->ti_urp);

	/*
	 * Drop TCP, IP headers and TCP options.
	 */
	m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
	m->m_len  -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

	/*
	 * Locate pcb for segment.
	 */
findso:
	so = slirp->tcp_last_so;
	if (so->so_fport != ti->ti_dport ||
	    so->so_lport != ti->ti_sport ||
	    so->so_laddr.s_addr != ti->ti_src.s_addr ||
	    so->so_faddr.s_addr != ti->ti_dst.s_addr) {
		so = solookup(&slirp->tcb, ti->ti_src, ti->ti_sport,
			       ti->ti_dst, ti->ti_dport);
		if (so)
			slirp->tcp_last_so = so;
	}

	/*
	 * If the state is CLOSED (i.e., TCB does not exist) then
	 * all data in the incoming segment is discarded.
	 * If the TCB exists but is in CLOSED state, it is embryonic,
	 * but should either do a listen or a connect soon.
	 *
	 * state == CLOSED means we've done socreate() but haven't
	 * attached it to a protocol yet...
	 *
	 * XXX If a TCB does not exist, and the TH_SYN flag is
	 * the only flag set, then create a session, mark it
	 * as if it was LISTENING, and continue...
	 */
        if (so == NULL) {
          if (slirp->restricted) {
            /* Any hostfwds will have an existing socket, so we only get here
             * for non-hostfwd connections. These should be dropped, unless it
             * happens to be a guestfwd.
             */
            for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
                if (ex_ptr->ex_fport == ti->ti_dport &&
                    ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) {
                    break;
                }
            }
            if (!ex_ptr) {
                goto dropwithreset;
            }
          }

	  if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
	    goto dropwithreset;

	  if ((so = socreate(slirp)) == NULL)
	    goto dropwithreset;
	  if (tcp_attach(so) < 0) {
	    free(so); /* Not sofree (if it failed, it's not insqued) */
	    goto dropwithreset;
	  }

	  sbreserve(&so->so_snd, TCP_SNDSPACE);
	  sbreserve(&so->so_rcv, TCP_RCVSPACE);

	  so->so_laddr = ti->ti_src;
	  so->so_lport = ti->ti_sport;
	  so->so_faddr = ti->ti_dst;
	  so->so_fport = ti->ti_dport;

	  if ((so->so_iptos = tcp_tos(so)) == 0)
	    so->so_iptos = ((struct ip *)ti)->ip_tos;

	  tp = sototcpcb(so);
	  tp->t_state = TCPS_LISTEN;
	}

        /*
         * If this is a still-connecting socket, this probably
         * a retransmit of the SYN.  Whether it's a retransmit SYN
	 * or something else, we nuke it.
         */
        if (so->so_state & SS_ISFCONNECTING)
                goto drop;

	tp = sototcpcb(so);

	/* XXX Should never fail */
        if (tp == NULL)
		goto dropwithreset;
	if (tp->t_state == TCPS_CLOSED)
		goto drop;

	tiwin = ti->ti_win;

	/*
	 * Segment received on connection.
	 * Reset idle time and keep-alive timer.
	 */
	tp->t_idle = 0;
	if (SO_OPTIONS)
	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL;
	else
	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE;

	/*
	 * Process options if not in LISTEN state,
	 * else do it below (after getting remote address).
	 */
	if (optp && tp->t_state != TCPS_LISTEN)
		tcp_dooptions(tp, (u_char *)optp, optlen, ti);

	/*
	 * Header prediction: check for the two common cases
	 * of a uni-directional data xfer.  If the packet has
	 * no control flags, is in-sequence, the window didn't
	 * change and we're not retransmitting, it's a
	 * candidate.  If the length is zero and the ack moved
	 * forward, we're the sender side of the xfer.  Just
	 * free the data acked & wake any higher level process
	 * that was blocked waiting for space.  If the length
	 * is non-zero and the ack didn't move, we're the
	 * receiver side.  If we're getting packets in-order
	 * (the reassembly queue is empty), add the data to
	 * the socket buffer and note that we need a delayed ack.
	 *
	 * XXX Some of these tests are not needed
	 * eg: the tiwin == tp->snd_wnd prevents many more
	 * predictions.. with no *real* advantage..
	 */
	if (tp->t_state == TCPS_ESTABLISHED &&
	    (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
	    ti->ti_seq == tp->rcv_nxt &&
	    tiwin && tiwin == tp->snd_wnd &&
	    tp->snd_nxt == tp->snd_max) {
		if (ti->ti_len == 0) {
			if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
			    SEQ_LEQ(ti->ti_ack, tp->snd_max) &&
			    tp->snd_cwnd >= tp->snd_wnd) {
				/*
				 * this is a pure ack for outstanding data.
				 */
				if (tp->t_rtt &&
				    SEQ_GT(ti->ti_ack, tp->t_rtseq))
					tcp_xmit_timer(tp, tp->t_rtt);
				acked = ti->ti_ack - tp->snd_una;
				sbdrop(&so->so_snd, acked);
				tp->snd_una = ti->ti_ack;
				m_free(m);

				/*
				 * If all outstanding data are acked, stop
				 * retransmit timer, otherwise restart timer
				 * using current (possibly backed-off) value.
				 * If process is waiting for space,
				 * wakeup/selwakeup/signal.  If data
				 * are ready to send, let tcp_output
				 * decide between more output or persist.
				 */
				if (tp->snd_una == tp->snd_max)
					tp->t_timer[TCPT_REXMT] = 0;
				else if (tp->t_timer[TCPT_PERSIST] == 0)
					tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;

				/*
				 * This is called because sowwakeup might have
				 * put data into so_snd.  Since we don't so sowwakeup,
				 * we don't need this.. XXX???
				 */
				if (so->so_snd.sb_cc)
					(void) tcp_output(tp);

				return;
			}
		} else if (ti->ti_ack == tp->snd_una &&
		    tcpfrag_list_empty(tp) &&
		    ti->ti_len <= sbspace(&so->so_rcv)) {
			/*
			 * this is a pure, in-sequence data packet
			 * with nothing on the reassembly queue and
			 * we have enough buffer space to take it.
			 */
			tp->rcv_nxt += ti->ti_len;
			/*
			 * Add data to socket buffer.
			 */
			if (so->so_emu) {
				if (tcp_emu(so,m)) sbappend(so, m);
			} else
				sbappend(so, m);

			/*
			 * If this is a short packet, then ACK now - with Nagel
			 *	congestion avoidance sender won't send more until
			 *	he gets an ACK.
			 *
			 * It is better to not delay acks at all to maximize
			 * TCP throughput.  See RFC 2581.
			 */
			tp->t_flags |= TF_ACKNOW;
			tcp_output(tp);
			return;
		}
	} /* header prediction */
	/*
	 * Calculate amount of space in receive window,
	 * and then do TCP input processing.
	 * Receive window is amount of space in rcv queue,
	 * but not less than advertised window.
	 */
	{ int win;
          win = sbspace(&so->so_rcv);
	  if (win < 0)
	    win = 0;
	  tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
	}

	switch (tp->t_state) {

	/*
	 * If the state is LISTEN then ignore segment if it contains an RST.
	 * If the segment contains an ACK then it is bad and send a RST.
	 * If it does not contain a SYN then it is not interesting; drop it.
	 * Don't bother responding if the destination was a broadcast.
	 * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
	 * tp->iss, and send a segment:
	 *     <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
	 * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
	 * Fill in remote peer address fields if not previously specified.
	 * Enter SYN_RECEIVED state, and process any other fields of this
	 * segment in this state.
	 */
	case TCPS_LISTEN: {

	  if (tiflags & TH_RST)
	    goto drop;
	  if (tiflags & TH_ACK)
	    goto dropwithreset;
	  if ((tiflags & TH_SYN) == 0)
	    goto drop;

	  /*
	   * This has way too many gotos...
	   * But a bit of spaghetti code never hurt anybody :)
	   */

	  /*
	   * If this is destined for the control address, then flag to
	   * tcp_ctl once connected, otherwise connect
	   */
	  if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
	      slirp->vnetwork_addr.s_addr) {
	    if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr &&
		so->so_faddr.s_addr != slirp->vnameserver_addr.s_addr) {
		/* May be an add exec */
		for (ex_ptr = slirp->exec_list; ex_ptr;
		     ex_ptr = ex_ptr->ex_next) {
		  if(ex_ptr->ex_fport == so->so_fport &&
		     so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
		    so->so_state |= SS_CTL;
		    break;
		  }
		}
		if (so->so_state & SS_CTL) {
		    goto cont_input;
		}
	    }
	    /* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */
	  }

	  if (so->so_emu & EMU_NOCONNECT) {
	    so->so_emu &= ~EMU_NOCONNECT;
	    goto cont_input;
	  }

          if ((tcp_fconnect(so) == -1) &&
#if defined(_WIN32)
              socket_error() != WSAEWOULDBLOCK
#else
              (errno != EINPROGRESS) && (errno != EWOULDBLOCK)
#endif
          ) {
	    u_char code=ICMP_UNREACH_NET;
	    DEBUG_MISC((dfd, " tcp fconnect errno = %d-%s\n",
			errno,strerror(errno)));
	    if(errno == ECONNREFUSED) {
	      /* ACK the SYN, send RST to refuse the connection */
	      tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0,
			  TH_RST|TH_ACK);
	    } else {
	      if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
	      HTONL(ti->ti_seq);             /* restore tcp header */
	      HTONL(ti->ti_ack);
	      HTONS(ti->ti_win);
	      HTONS(ti->ti_urp);
	      m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
	      m->m_len  += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
	      *ip=save_ip;
	      icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));
	    }
            tcp_close(tp);
	    m_free(m);
	  } else {
	    /*
	     * Haven't connected yet, save the current mbuf
	     * and ti, and return
	     * XXX Some OS's don't tell us whether the connect()
	     * succeeded or not.  So we must time it out.
	     */
	    so->so_m = m;
	    so->so_ti = ti;
	    tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
	    tp->t_state = TCPS_SYN_RECEIVED;
	    tcp_template(tp);
	  }
	  return;

	cont_conn:
	  /* m==NULL
	   * Check if the connect succeeded
	   */
	  if (so->so_state & SS_NOFDREF) {
	    tp = tcp_close(tp);
	    goto dropwithreset;
	  }
	cont_input:
	  tcp_template(tp);

	  if (optp)
	    tcp_dooptions(tp, (u_char *)optp, optlen, ti);

	  if (iss)
	    tp->iss = iss;
	  else
	    tp->iss = slirp->tcp_iss;
	  slirp->tcp_iss += TCP_ISSINCR/2;
	  tp->irs = ti->ti_seq;
	  tcp_sendseqinit(tp);
	  tcp_rcvseqinit(tp);
	  tp->t_flags |= TF_ACKNOW;
	  tp->t_state = TCPS_SYN_RECEIVED;
	  tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
	  goto trimthenstep6;
	} /* case TCPS_LISTEN */

	/*
	 * If the state is SYN_SENT:
	 *	if seg contains an ACK, but not for our SYN, drop the input.
	 *	if seg contains a RST, then drop the connection.
	 *	if seg does not contain SYN, then drop it.
	 * Otherwise this is an acceptable SYN segment
	 *	initialize tp->rcv_nxt and tp->irs
	 *	if seg contains ack then advance tp->snd_una
	 *	if SYN has been acked change to ESTABLISHED else SYN_RCVD state
	 *	arrange for segment to be acked (eventually)
	 *	continue processing rest of data/controls, beginning with URG
	 */
	case TCPS_SYN_SENT:
		if ((tiflags & TH_ACK) &&
		    (SEQ_LEQ(ti->ti_ack, tp->iss) ||
		     SEQ_GT(ti->ti_ack, tp->snd_max)))
			goto dropwithreset;

		if (tiflags & TH_RST) {
                        if (tiflags & TH_ACK) {
                                tcp_drop(tp, 0); /* XXX Check t_softerror! */
                        }
			goto drop;
		}

		if ((tiflags & TH_SYN) == 0)
			goto drop;
		if (tiflags & TH_ACK) {
			tp->snd_una = ti->ti_ack;
			if (SEQ_LT(tp->snd_nxt, tp->snd_una))
				tp->snd_nxt = tp->snd_una;
		}

		tp->t_timer[TCPT_REXMT] = 0;
		tp->irs = ti->ti_seq;
		tcp_rcvseqinit(tp);
		tp->t_flags |= TF_ACKNOW;
		if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {
			soisfconnected(so);
			tp->t_state = TCPS_ESTABLISHED;

			(void) tcp_reass(tp, (struct tcpiphdr *)0,
				(struct mbuf *)0);
			/*
			 * if we didn't have to retransmit the SYN,
			 * use its rtt as our initial srtt & rtt var.
			 */
			if (tp->t_rtt)
				tcp_xmit_timer(tp, tp->t_rtt);
		} else
			tp->t_state = TCPS_SYN_RECEIVED;

trimthenstep6:
		/*
		 * Advance ti->ti_seq to correspond to first data byte.
		 * If data, trim to stay within window,
		 * dropping FIN if necessary.
		 */
		ti->ti_seq++;
		if (ti->ti_len > tp->rcv_wnd) {
			todrop = ti->ti_len - tp->rcv_wnd;
			m_adj(m, -todrop);
			ti->ti_len = tp->rcv_wnd;
			tiflags &= ~TH_FIN;
		}
		tp->snd_wl1 = ti->ti_seq - 1;
		tp->rcv_up = ti->ti_seq;
		goto step6;
	} /* switch tp->t_state */
	/*
	 * States other than LISTEN or SYN_SENT.
	 * Check that at least some bytes of segment are within
	 * receive window.  If segment begins before rcv_nxt,
	 * drop leading data (and SYN); if nothing left, just ack.
	 */
	todrop = tp->rcv_nxt - ti->ti_seq;
	if (todrop > 0) {
		if (tiflags & TH_SYN) {
			tiflags &= ~TH_SYN;
			ti->ti_seq++;
			if (ti->ti_urp > 1)
				ti->ti_urp--;
			else
				tiflags &= ~TH_URG;
			todrop--;
		}
		/*
		 * Following if statement from Stevens, vol. 2, p. 960.
		 */
		if (todrop > ti->ti_len
		    || (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {
			/*
			 * Any valid FIN must be to the left of the window.
			 * At this point the FIN must be a duplicate or out
			 * of sequence; drop it.
			 */
			tiflags &= ~TH_FIN;

			/*
			 * Send an ACK to resynchronize and drop any data.
			 * But keep on processing for RST or ACK.
			 */
			tp->t_flags |= TF_ACKNOW;
			todrop = ti->ti_len;
		}
		m_adj(m, todrop);
		ti->ti_seq += todrop;
		ti->ti_len -= todrop;
		if (ti->ti_urp > todrop)
			ti->ti_urp -= todrop;
		else {
			tiflags &= ~TH_URG;
			ti->ti_urp = 0;
		}
	}
	/*
	 * If new data are received on a connection after the
	 * user processes are gone, then RST the other end.
	 */
	if ((so->so_state & SS_NOFDREF) &&
	    tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {
		tp = tcp_close(tp);
		goto dropwithreset;
	}

	/*
	 * If segment ends after window, drop trailing data
	 * (and PUSH and FIN); if nothing left, just ACK.
	 */
	todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
	if (todrop > 0) {
		if (todrop >= ti->ti_len) {
			/*
			 * If a new connection request is received
			 * while in TIME_WAIT, drop the old connection
			 * and start over if the sequence numbers
			 * are above the previous ones.
			 */
			if (tiflags & TH_SYN &&
			    tp->t_state == TCPS_TIME_WAIT &&
			    SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {
				iss = tp->rcv_nxt + TCP_ISSINCR;
				tp = tcp_close(tp);
				goto findso;
			}
			/*
			 * If window is closed can only take segments at
			 * window edge, and have to drop data and PUSH from
			 * incoming segments.  Continue processing, but
			 * remember to ack.  Otherwise, drop segment
			 * and ack.
			 */
			if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {
				tp->t_flags |= TF_ACKNOW;
			} else {
				goto dropafterack;
			}
		}
		m_adj(m, -todrop);
		ti->ti_len -= todrop;
		tiflags &= ~(TH_PUSH|TH_FIN);
	}

	/*
	 * If the RST bit is set examine the state:
	 *    SYN_RECEIVED STATE:
	 *	If passive open, return to LISTEN state.
	 *	If active open, inform user that connection was refused.
	 *    ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
	 *	Inform user that connection was reset, and close tcb.
	 *    CLOSING, LAST_ACK, TIME_WAIT STATES
	 *	Close the tcb.
	 */
	if (tiflags&TH_RST) switch (tp->t_state) {

	case TCPS_SYN_RECEIVED:
	case TCPS_ESTABLISHED:
	case TCPS_FIN_WAIT_1:
	case TCPS_FIN_WAIT_2:
	case TCPS_CLOSE_WAIT:
		tp->t_state = TCPS_CLOSED;
                tcp_close(tp);
		goto drop;

	case TCPS_CLOSING:
	case TCPS_LAST_ACK:
	case TCPS_TIME_WAIT:
                tcp_close(tp);
		goto drop;
	}

	/*
	 * If a SYN is in the window, then this is an
	 * error and we send an RST and drop the connection.
	 */
	if (tiflags & TH_SYN) {
		tp = tcp_drop(tp,0);
		goto dropwithreset;
	}

	/*
	 * If the ACK bit is off we drop the segment and return.
	 */
	if ((tiflags & TH_ACK) == 0) goto drop;

	/*
	 * Ack processing.
	 */
	switch (tp->t_state) {
	/*
	 * In SYN_RECEIVED state if the ack ACKs our SYN then enter
	 * ESTABLISHED state and continue processing, otherwise
	 * send an RST.  una<=ack<=max
	 */
	case TCPS_SYN_RECEIVED:

		if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
		    SEQ_GT(ti->ti_ack, tp->snd_max))
			goto dropwithreset;
		tp->t_state = TCPS_ESTABLISHED;
		/*
		 * The sent SYN is ack'ed with our sequence number +1
		 * The first data byte already in the buffer will get
		 * lost if no correction is made.  This is only needed for
		 * SS_CTL since the buffer is empty otherwise.
		 * tp->snd_una++; or:
		 */
		tp->snd_una=ti->ti_ack;
		if (so->so_state & SS_CTL) {
		  /* So tcp_ctl reports the right state */
		  ret = tcp_ctl(so);
		  if (ret == 1) {
		    soisfconnected(so);
		    so->so_state &= ~SS_CTL;   /* success XXX */
		  } else if (ret == 2) {
		    so->so_state &= SS_PERSISTENT_MASK;
		    so->so_state |= SS_NOFDREF; /* CTL_CMD */
		  } else {
		    needoutput = 1;
		    tp->t_state = TCPS_FIN_WAIT_1;
		  }
		} else {
		  soisfconnected(so);
		}

		(void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0);
		tp->snd_wl1 = ti->ti_seq - 1;
		/* Avoid ack processing; snd_una==ti_ack  =>  dup ack */
		goto synrx_to_est;
		/* fall into ... */

	/*
	 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
	 * ACKs.  If the ack is in the range
	 *	tp->snd_una < ti->ti_ack <= tp->snd_max
	 * then advance tp->snd_una to ti->ti_ack and drop
	 * data from the retransmission queue.  If this ACK reflects
	 * more up to date window information we update our window information.
	 */
	case TCPS_ESTABLISHED:
	case TCPS_FIN_WAIT_1:
	case TCPS_FIN_WAIT_2:
	case TCPS_CLOSE_WAIT:
	case TCPS_CLOSING:
	case TCPS_LAST_ACK:
	case TCPS_TIME_WAIT:

		if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
			if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {
			  DEBUG_MISC((dfd, " dup ack  m = %lx  so = %lx\n",
				      (long )m, (long )so));
				/*
				 * If we have outstanding data (other than
				 * a window probe), this is a completely
				 * duplicate ack (ie, window info didn't
				 * change), the ack is the biggest we've
				 * seen and we've seen exactly our rexmt
				 * threshold of them, assume a packet
				 * has been dropped and retransmit it.
				 * Kludge snd_nxt & the congestion
				 * window so we send only this one
				 * packet.
				 *
				 * We know we're losing at the current
				 * window size so do congestion avoidance
				 * (set ssthresh to half the current window
				 * and pull our congestion window back to
				 * the new ssthresh).
				 *
				 * Dup acks mean that packets have left the
				 * network (they're now cached at the receiver)
				 * so bump cwnd by the amount in the receiver
				 * to keep a constant cwnd packets in the
				 * network.
				 */
				if (tp->t_timer[TCPT_REXMT] == 0 ||
				    ti->ti_ack != tp->snd_una)
					tp->t_dupacks = 0;
				else if (++tp->t_dupacks == TCPREXMTTHRESH) {
					tcp_seq onxt = tp->snd_nxt;
					u_int win =
					    min(tp->snd_wnd, tp->snd_cwnd) / 2 /
						tp->t_maxseg;

					if (win < 2)
						win = 2;
					tp->snd_ssthresh = win * tp->t_maxseg;
					tp->t_timer[TCPT_REXMT] = 0;
					tp->t_rtt = 0;
					tp->snd_nxt = ti->ti_ack;
					tp->snd_cwnd = tp->t_maxseg;
					(void) tcp_output(tp);
					tp->snd_cwnd = tp->snd_ssthresh +
					       tp->t_maxseg * tp->t_dupacks;
					if (SEQ_GT(onxt, tp->snd_nxt))
						tp->snd_nxt = onxt;
					goto drop;
				} else if (tp->t_dupacks > TCPREXMTTHRESH) {
					tp->snd_cwnd += tp->t_maxseg;
					(void) tcp_output(tp);
					goto drop;
				}
			} else
				tp->t_dupacks = 0;
			break;
		}
	synrx_to_est:
		/*
		 * If the congestion window was inflated to account
		 * for the other side's cached packets, retract it.
		 */
		if (tp->t_dupacks > TCPREXMTTHRESH &&
		    tp->snd_cwnd > tp->snd_ssthresh)
			tp->snd_cwnd = tp->snd_ssthresh;
		tp->t_dupacks = 0;
		if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
			goto dropafterack;
		}
		acked = ti->ti_ack - tp->snd_una;

		/*
		 * If transmit timer is running and timed sequence
		 * number was acked, update smoothed round trip time.
		 * Since we now have an rtt measurement, cancel the
		 * timer backoff (cf., Phil Karn's retransmit alg.).
		 * Recompute the initial retransmit timer.
		 */
		if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
			tcp_xmit_timer(tp,tp->t_rtt);

		/*
		 * If all outstanding data is acked, stop retransmit
		 * timer and remember to restart (more output or persist).
		 * If there is more data to be acked, restart retransmit
		 * timer, using current (possibly backed-off) value.
		 */
		if (ti->ti_ack == tp->snd_max) {
			tp->t_timer[TCPT_REXMT] = 0;
			needoutput = 1;
		} else if (tp->t_timer[TCPT_PERSIST] == 0)
			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
		/*
		 * When new data is acked, open the congestion window.
		 * If the window gives us less than ssthresh packets
		 * in flight, open exponentially (maxseg per packet).
		 * Otherwise open linearly: maxseg per window
		 * (maxseg^2 / cwnd per packet).
		 */
		{
		  register u_int cw = tp->snd_cwnd;
		  register u_int incr = tp->t_maxseg;

		  if (cw > tp->snd_ssthresh)
		    incr = incr * incr / cw;
		  tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
		}
		if (acked > so->so_snd.sb_cc) {
			tp->snd_wnd -= so->so_snd.sb_cc;
			sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
			ourfinisacked = 1;
		} else {
			sbdrop(&so->so_snd, acked);
			tp->snd_wnd -= acked;
			ourfinisacked = 0;
		}
		tp->snd_una = ti->ti_ack;
		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
			tp->snd_nxt = tp->snd_una;

		switch (tp->t_state) {

		/*
		 * In FIN_WAIT_1 STATE in addition to the processing
		 * for the ESTABLISHED state if our FIN is now acknowledged
		 * then enter FIN_WAIT_2.
		 */
		case TCPS_FIN_WAIT_1:
			if (ourfinisacked) {
				/*
				 * If we can't receive any more
				 * data, then closing user can proceed.
				 * Starting the timer is contrary to the
				 * specification, but if we don't get a FIN
				 * we'll hang forever.
				 */
				if (so->so_state & SS_FCANTRCVMORE) {
					tp->t_timer[TCPT_2MSL] = TCP_MAXIDLE;
				}
				tp->t_state = TCPS_FIN_WAIT_2;
			}
			break;

	 	/*
		 * In CLOSING STATE in addition to the processing for
		 * the ESTABLISHED state if the ACK acknowledges our FIN
		 * then enter the TIME-WAIT state, otherwise ignore
		 * the segment.
		 */
		case TCPS_CLOSING:
			if (ourfinisacked) {
				tp->t_state = TCPS_TIME_WAIT;
				tcp_canceltimers(tp);
				tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			}
			break;

		/*
		 * In LAST_ACK, we may still be waiting for data to drain
		 * and/or to be acked, as well as for the ack of our FIN.
		 * If our FIN is now acknowledged, delete the TCB,
		 * enter the closed state and return.
		 */
		case TCPS_LAST_ACK:
			if (ourfinisacked) {
                                tcp_close(tp);
				goto drop;
			}
			break;

		/*
		 * In TIME_WAIT state the only thing that should arrive
		 * is a retransmission of the remote FIN.  Acknowledge
		 * it and restart the finack timer.
		 */
		case TCPS_TIME_WAIT:
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			goto dropafterack;
		}
	} /* switch(tp->t_state) */

step6:
	/*
	 * Update window information.
	 * Don't look at window if no ACK: TAC's send garbage on first SYN.
	 */
	if ((tiflags & TH_ACK) &&
	    (SEQ_LT(tp->snd_wl1, ti->ti_seq) ||
	    (tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
	    (tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) {
		tp->snd_wnd = tiwin;
		tp->snd_wl1 = ti->ti_seq;
		tp->snd_wl2 = ti->ti_ack;
		if (tp->snd_wnd > tp->max_sndwnd)
			tp->max_sndwnd = tp->snd_wnd;
		needoutput = 1;
	}

	/*
	 * Process segments with URG.
	 */
	if ((tiflags & TH_URG) && ti->ti_urp &&
	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
		/*
		 * This is a kludge, but if we receive and accept
		 * random urgent pointers, we'll crash in
		 * soreceive.  It's hard to imagine someone
		 * actually wanting to send this much urgent data.
		 */
		if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {
			ti->ti_urp = 0;
			tiflags &= ~TH_URG;
			goto dodata;
		}
		/*
		 * If this segment advances the known urgent pointer,
		 * then mark the data stream.  This should not happen
		 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
		 * a FIN has been received from the remote side.
		 * In these states we ignore the URG.
		 *
		 * According to RFC961 (Assigned Protocols),
		 * the urgent pointer points to the last octet
		 * of urgent data.  We continue, however,
		 * to consider it to indicate the first octet
		 * of data past the urgent section as the original
		 * spec states (in one of two places).
		 */
		if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
			tp->rcv_up = ti->ti_seq + ti->ti_urp;
			so->so_urgc =  so->so_rcv.sb_cc +
				(tp->rcv_up - tp->rcv_nxt); /* -1; */
			tp->rcv_up = ti->ti_seq + ti->ti_urp;

		}
	} else
		/*
		 * If no out of band data is expected,
		 * pull receive urgent pointer along
		 * with the receive window.
		 */
		if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
			tp->rcv_up = tp->rcv_nxt;
dodata:

	/*
	 * If this is a small packet, then ACK now - with Nagel
	 *      congestion avoidance sender won't send more until
	 *      he gets an ACK.
	 */
	if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&
	    ((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
		tp->t_flags |= TF_ACKNOW;
	}

	/*
	 * Process the segment text, merging it into the TCP sequencing queue,
	 * and arranging for acknowledgment of receipt if necessary.
	 * This process logically involves adjusting tp->rcv_wnd as data
	 * is presented to the user (this happens in tcp_usrreq.c,
	 * case PRU_RCVD).  If a FIN has already been received on this
	 * connection then we just ignore the text.
	 */
	if ((ti->ti_len || (tiflags&TH_FIN)) &&
	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
		TCP_REASS(tp, ti, m, so, tiflags);
	} else {
		m_free(m);
		tiflags &= ~TH_FIN;
	}

	/*
	 * If FIN is received ACK the FIN and let the user know
	 * that the connection is closing.
	 */
	if (tiflags & TH_FIN) {
		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
			/*
			 * If we receive a FIN we can't send more data,
			 * set it SS_FDRAIN
                         * Shutdown the socket if there is no rx data in the
			 * buffer.
			 * soread() is called on completion of shutdown() and
			 * will got to TCPS_LAST_ACK, and use tcp_output()
			 * to send the FIN.
			 */
			sofwdrain(so);

			tp->t_flags |= TF_ACKNOW;
			tp->rcv_nxt++;
		}
		switch (tp->t_state) {

	 	/*
		 * In SYN_RECEIVED and ESTABLISHED STATES
		 * enter the CLOSE_WAIT state.
		 */
		case TCPS_SYN_RECEIVED:
		case TCPS_ESTABLISHED:
		  if(so->so_emu == EMU_CTL)        /* no shutdown on socket */
		    tp->t_state = TCPS_LAST_ACK;
		  else
		    tp->t_state = TCPS_CLOSE_WAIT;
		  break;

	 	/*
		 * If still in FIN_WAIT_1 STATE FIN has not been acked so
		 * enter the CLOSING state.
		 */
		case TCPS_FIN_WAIT_1:
			tp->t_state = TCPS_CLOSING;
			break;

	 	/*
		 * In FIN_WAIT_2 state enter the TIME_WAIT state,
		 * starting the time-wait timer, turning off the other
		 * standard timers.
		 */
		case TCPS_FIN_WAIT_2:
			tp->t_state = TCPS_TIME_WAIT;
			tcp_canceltimers(tp);
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			break;

		/*
		 * In TIME_WAIT state restart the 2 MSL time_wait timer.
		 */
		case TCPS_TIME_WAIT:
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			break;
		}
	}

	/*
	 * Return any desired output.
	 */
	if (needoutput || (tp->t_flags & TF_ACKNOW)) {
		(void) tcp_output(tp);
	}
	return;

dropafterack:
	/*
	 * Generate an ACK dropping incoming segment if it occupies
	 * sequence space, where the ACK reflects our state.
	 */
	if (tiflags & TH_RST)
		goto drop;
	m_free(m);
	tp->t_flags |= TF_ACKNOW;
	(void) tcp_output(tp);
	return;

dropwithreset:
	/* reuses m if m!=NULL, m_free() unnecessary */
	if (tiflags & TH_ACK)
		tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
	else {
		if (tiflags & TH_SYN) ti->ti_len++;
		tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
		    TH_RST|TH_ACK);
	}

	return;

drop:
	/*
	 * Drop space held by incoming segment and return.
	 */
	m_free(m);
}
Пример #17
0
void tcp_cleanup(Slirp *slirp)
{
    while (slirp->tcb.so_next != &slirp->tcb) {
        tcp_close(sototcpcb(slirp->tcb.so_next));
    }
}
Пример #18
0
/*
 * Write data from so_rcv to so's socket,
 * updating all sbuf field as necessary
 */
int
sowrite(struct socket *so)
{
	int  n,nn;
	struct sbuf *sb = &so->so_rcv;
	int len = sb->sb_cc;
	struct iovec iov[2];

	DEBUG_CALL("sowrite");
	DEBUG_ARG("so = %lx", (long)so);

	if (so->so_urgc) {
		sosendoob(so);
		if (sb->sb_cc == 0)
			return 0;
	}

	/*
	 * No need to check if there's something to write,
	 * sowrite wouldn't have been called otherwise
	 */

	iov[0].iov_base = sb->sb_rptr;
        iov[1].iov_base = NULL;
        iov[1].iov_len = 0;
	if (sb->sb_rptr < sb->sb_wptr) {
		iov[0].iov_len = sb->sb_wptr - sb->sb_rptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		n = 1;
	} else {
		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		len -= iov[0].iov_len;
		if (len) {
			iov[1].iov_base = sb->sb_data;
			iov[1].iov_len = sb->sb_wptr - sb->sb_data;
			if (iov[1].iov_len > len) iov[1].iov_len = len;
			n = 2;
		} else
			n = 1;
	}
	/* Check if there's urgent data to send, and if so, send it */

#ifdef HAVE_READV
	nn = writev(so->s, (const struct iovec *)iov, n);

	DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
#else
	nn = slirp_send(so, iov[0].iov_base, iov[0].iov_len,0);
#endif
	/* This should never happen, but people tell me it does *shrug* */
	if (nn < 0 && (errno == EAGAIN || errno == EINTR))
		return 0;

	if (nn <= 0) {
		DEBUG_MISC((dfd, " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
			so->so_state, errno));
		sofcantsendmore(so);
		tcp_sockclosed(sototcpcb(so));
		return -1;
	}

#ifndef HAVE_READV
	if (n == 2 && nn == iov[0].iov_len) {
            int ret;
            ret = slirp_send(so, iov[1].iov_base, iov[1].iov_len,0);
            if (ret > 0)
                nn += ret;
        }
        DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
#endif

	/* Update sbuf */
	sb->sb_cc -= nn;
	sb->sb_rptr += nn;
	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_rptr -= sb->sb_datalen;

	/*
	 * If in DRAIN mode, and there's no more data, set
	 * it CANTSENDMORE
	 */
	if ((so->so_state & SS_FWDRAIN) && sb->sb_cc == 0)
		sofcantsendmore(so);

	return nn;
}
Пример #19
0
/*
 * Read from so's socket into sb_snd, updating all relevant sbuf fields
 * NOTE: This will only be called if it is select()ed for reading, so
 * a read() of 0 (or less) means it's disconnected
 */
int
soread(struct socket *so)
{
	int n, nn;
	struct sbuf *sb = &so->so_snd;
	struct iovec iov[2];

	DEBUG_CALL("soread");
	DEBUG_ARG("so = %p", so);

	/*
	 * No need to check if there's enough room to read.
	 * soread wouldn't have been called if there weren't
	 */
	sopreprbuf(so, iov, &n);

#ifdef HAVE_READV
	nn = readv(so->s, (struct iovec *)iov, n);
	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#else
	nn = qemu_recv(so->s, iov[0].iov_base, iov[0].iov_len,0);
#endif
	if (nn <= 0) {
		if (nn < 0 && (errno == EINTR || errno == EAGAIN))
			return 0;
		else {
			int err;
			socklen_t slen = sizeof err;

			err = errno;
			if (nn == 0) {
				getsockopt(so->s, SOL_SOCKET, SO_ERROR,
					   &err, &slen);
			}

			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));
			sofcantrcvmore(so);

			if (err == ECONNRESET || err == ECONNREFUSED
			    || err == ENOTCONN || err == EPIPE) {
				tcp_drop(sototcpcb(so), err);
			} else {
				tcp_sockclosed(sototcpcb(so));
			}
			return -1;
		}
	}

#ifndef HAVE_READV
	/*
	 * If there was no error, try and read the second time round
	 * We read again if n = 2 (ie, there's another part of the buffer)
	 * and we read as much as we could in the first read
	 * We don't test for <= 0 this time, because there legitimately
	 * might not be any more data (since the socket is non-blocking),
	 * a close will be detected on next iteration.
	 * A return of -1 won't (shouldn't) happen, since it didn't happen above
	 */
	if (n == 2 && nn == iov[0].iov_len) {
            int ret;
            ret = qemu_recv(so->s, iov[1].iov_base, iov[1].iov_len,0);
            if (ret > 0)
                nn += ret;
        }

	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#endif

	/* Update fields */
	sb->sb_cc += nn;
	sb->sb_wptr += nn;
	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_wptr -= sb->sb_datalen;
	return nn;
}