[lwip-users] Snd_buf not updated when receiving SYN in state SYN_SENT

[Magnus Christensson]

Hi,

the code that handles an incoming SYN and ACK in tcp_process doesn't update 
snd_buf. The code is:

  /* Do different things depending on the TCP state. */
  switch (pcb->state) {
  case SYN_SENT:
    LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %lu pcb->snd_nxt %lu unacked 
%lu\n", ackno,
     pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
    if ((flags & TCP_ACK) && (flags & TCP_SYN)
        && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
      pcb->rcv_nxt = seqno + 1;
      pcb->lastack = ackno;
      pcb->snd_wnd = tcphdr->wnd;
      pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window 
update */
      pcb->state = ESTABLISHED;
      pcb->cwnd = pcb->mss;
      --pcb->snd_queuelen;
      LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %u\n", 
(unsigned int)pcb->snd_queuelen));
      rseg = pcb->unacked;
      pcb->unacked = rseg->next;
      tcp_seg_free(rseg);

      /* Parse any options in the SYNACK. */
      tcp_parseopt(pcb);

      /* Call the user specified function to call when sucessfully
       * connected. */
      TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
      tcp_ack(pcb);
    }

Am I missing something, or shouldn't there be a 'pcb->snd_buf++' to update the 
send buffer size from the incoming ACK?

M.