tcp_output.c

LwIP adaptation for Fujitsu MB90f497 and CS8900A Ethernet driver

#ifdef LWIP_DEBUG
  if(pcb->snd_queuelen != 0) {
    ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
	   pcb->unsent != NULL);
    
  }
#endif /* LWIP_DEBUG */
  DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %d (with mem err)\n", pcb->snd_queuelen));
  return ERR_MEM;
}
/*-----------------------------------------------------------------------------------*/
/* find out what we can send and send it */
err_t
tcp_output(struct tcp_pcb *pcb)
{
  struct pbuf *p;
  struct tcp_hdr *tcphdr;
  struct tcp_seg *seg, *useg;
  u32_t wnd;
#if TCP_CWND_DEBUG
  int i = 0;
#endif /* TCP_CWND_DEBUG */

  /* First, check if we are invoked by the TCP input processing
     code. If so, we do not output anything. Instead, we rely on the
     input processing code to call us when input processing is done
     with. */
  if(tcp_input_pcb == pcb) {
    return ERR_OK;
  }
  

  wnd = MIN(pcb->snd_wnd, pcb->cwnd);

  
  seg = pcb->unsent;

  /* If the TF_ACK_NOW flag is set, we check if there is data that is
     to be sent. If data is to be sent out, we'll just piggyback our
     acknowledgement with the outgoing segment. If no data will be
     sent (either because the ->unsent queue is empty or because the
     window doesn't allow it) we'll have to construct an empty ACK
     segment and send it. */
  if(pcb->flags & TF_ACK_NOW &&
     (seg == NULL ||
      ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
    pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
    p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM);
    if(p == NULL) {
      DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: (ACK) could not allocate pbuf\n"));
    	Put_String("tcp_output: pbuf_error:");
	mprintf((float)stats.mem.used,6,0);

      return ERR_BUF;
    }
    DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: sending ACK for %lu\n", pcb->rcv_nxt));    
    if(pbuf_header(p, TCP_HLEN)) {
      DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: (ACK) no room for TCP header in pbuf.\n"));
      
#ifdef TCP_STATS
      ++stats.tcp.err;
#endif /* TCP_STATS */
      pbuf_free(p);
    	Put_String("tcp_output: pbuf_error:");
	mprintf((float)stats.mem.used,6,0);

      return ERR_BUF;

    }

    
    tcphdr = p->payload;
    tcphdr->src = htons(pcb->local_port);
    tcphdr->dest = htons(pcb->remote_port);
    tcphdr->seqno = htonl(pcb->snd_nxt);
    tcphdr->ackno = htonl(pcb->rcv_nxt);
    TCPH_FLAGS_SET(tcphdr, TCP_ACK);
    tcphdr->wnd = htons(pcb->rcv_wnd);
    tcphdr->urgp = 0;
    TCPH_OFFSET_SET(tcphdr, 5 << 4);
    
    tcphdr->chksum = 0;
    tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
					IP_PROTO_TCP, p->tot_len);



    ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), TCP_TTL,
	      IP_PROTO_TCP);
    pbuf_free(p);

    return ERR_OK;
  } 
  
#if TCP_OUTPUT_DEBUG
  if(seg == NULL) {
    DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n", pcb->unsent));
  }
#endif /* TCP_OUTPUT_DEBUG */
#if TCP_CWND_DEBUG
  if(seg == NULL) {
    DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %lu, cwnd %lu, wnd %lu, seg == NULL, ack %lu\n",
                            pcb->snd_wnd, pcb->cwnd, wnd,
                            pcb->lastack));
  } else {
    DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %lu, cwnd %lu, wnd %lu, effwnd %lu, seq %lu, ack %lu\n",
                            pcb->snd_wnd, pcb->cwnd, wnd,
                            ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
                            ntohl(seg->tcphdr->seqno), pcb->lastack));
  }
#endif /* TCP_CWND_DEBUG */
  
  while(seg != NULL &&
	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
    pcb->rtime = 0;
#if TCP_CWND_DEBUG
    DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %lu, cwnd %lu, wnd %lu, effwnd %lu, seq %lu, ack %lu, i%d\n",
                            pcb->snd_wnd, pcb->cwnd, wnd,
                            ntohl(seg->tcphdr->seqno) + seg->len -
                            pcb->lastack,
                            ntohl(seg->tcphdr->seqno), pcb->lastack, i));
    ++i;
#endif /* TCP_CWND_DEBUG */

    pcb->unsent = seg->next;
    
    if(pcb->state != SYN_SENT) {
      TCPH_FLAGS_SET(seg->tcphdr, TCPH_FLAGS(seg->tcphdr) | TCP_ACK);
      pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
    }
 
   
    tcp_output_segment(seg, pcb);

    pcb->snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
    if(TCP_SEQ_LT(pcb->snd_max, pcb->snd_nxt)) {
      pcb->snd_max = pcb->snd_nxt;
    }
    /* put segment on unacknowledged list if length > 0 */
    if(TCP_TCPLEN(seg) > 0) {
      seg->next = NULL;
      if(pcb->unacked == NULL) {
        pcb->unacked = seg;
	
	
      } else {
        for(useg = pcb->unacked; useg->next != NULL; useg = useg->next);
        useg->next = seg;
      }
      /*      seg->rtime = 0;*/      
    } else {
      tcp_seg_free(seg);
    }
    seg = pcb->unsent;
  }  
  return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/
static void
tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
{
  u16_t len;
  struct netif *netif;

  /* The TCP header has already been constructed, but the ackno and
   wnd fields remain. */
  seg->tcphdr->ackno = htonl(pcb->rcv_nxt);

  /* silly window avoidance */
  if(pcb->rcv_wnd < pcb->mss) {
    seg->tcphdr->wnd = 0;
  } else {
    seg->tcphdr->wnd = htons(pcb->rcv_wnd);
  }

  /* If we don't have a local IP address, we get one by
     calling ip_route(). */
  if(ip_addr_isany(&(pcb->local_ip))) {
    netif = ip_route(&(pcb->remote_ip));
    if(netif == NULL) {
      return;
    }
    ip_addr_set(&(pcb->local_ip), &(netif->ip_addr));
  }

  pcb->rtime = 0;
  
  if(pcb->rttest == 0) {
    pcb->rttest = tcp_ticks;
    pcb->rtseq = ntohl(seg->tcphdr->seqno);

    DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %lu\n", pcb->rtseq));
  }
  DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %lu:%lu\n",
			    htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
			    seg->len));

  len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
  
  seg->p->len -= len;
  seg->p->tot_len -= len;
  
  seg->p->payload = seg->tcphdr;
    
  seg->tcphdr->chksum = 0;
  seg->tcphdr->chksum = inet_chksum_pseudo(seg->p,
					   &(pcb->local_ip),
					   &(pcb->remote_ip),
					   IP_PROTO_TCP, seg->p->tot_len);

#ifdef TCP_STATS
  ++stats.tcp.xmit;
#endif /* TCP_STATS */

  ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), TCP_TTL,
	    IP_PROTO_TCP);
}
/*-----------------------------------------------------------------------------------*/
void
tcp_rst(u32_t seqno, u32_t ackno,
	struct ip_addr *local_ip, struct ip_addr *remote_ip,
	u16_t local_port, u16_t remote_port)
{
  struct pbuf *p;
  struct tcp_hdr *tcphdr;
  p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM);
  if(p == NULL) {
    if(p == NULL) {
      DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
      return;
    }
  }
  if(pbuf_header(p, TCP_HLEN)) {
    DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_send_data: no room for TCP header in pbuf.\n"));

#ifdef TCP_STATS
    ++stats.tcp.err;
#endif /* TCP_STATS */
    return;
  }

  tcphdr = p->payload;
  tcphdr->src = htons(local_port);
  tcphdr->dest = htons(remote_port);
  tcphdr->seqno = htonl(seqno);
  tcphdr->ackno = htonl(ackno);
  TCPH_FLAGS_SET(tcphdr, TCP_RST | TCP_ACK);
  tcphdr->wnd = htons(TCP_WND);
  tcphdr->urgp = 0;
  TCPH_OFFSET_SET(tcphdr, 5 << 4);
  
  tcphdr->chksum = 0;
  tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
				      IP_PROTO_TCP, p->tot_len);

#ifdef TCP_STATS
  ++stats.tcp.xmit;
#endif /* TCP_STATS */
  ip_output(p, local_ip, remote_ip, TCP_TTL, IP_PROTO_TCP);
  pbuf_free(p);
  DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %lu ackno %lu.\n", seqno, ackno));
}
/*-----------------------------------------------------------------------------------*/
void
tcp_rexmit(struct tcp_pcb *pcb)
{
  struct tcp_seg *seg;
//Put_String("tcp_rexmit() ");

  if(pcb->unacked == NULL) {
    return;
  }
  
  /* Move all unacked segments to the unsent queue. */
  for(seg = pcb->unacked; seg->next != NULL; seg = seg->next);
  
  seg->next = pcb->unsent;
  pcb->unsent = pcb->unacked;
  
  pcb->unacked = NULL;
  
  
  pcb->snd_nxt = ntohl(pcb->unsent->tcphdr->seqno);
  
  ++pcb->nrtx;
  pcb->rtime = 0;
  
  /* Don't take any rtt measurements after retransmitting. */    
  pcb->rttest = 0;
  
  /* Do the actual retransmission. */
  tcp_output(pcb);

}