/*-----------------------------------------------------------------------------------*/
void
tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg)
{
u32_t wnd;
u16_t len, tot_len;
struct netif *netif;
DEBUGF(TCP_REXMIT_DEBUG, ("tcp_rexmit_seg: skickar %ld:%ld\n",
ntohl(seg->tcphdr->seqno),
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
wnd = MIN(pcb->snd_wnd, pcb->cwnd);
if(ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
/* Count the number of retranmissions. */
++pcb->nrtx;
if((netif = ip_route((struct ip_addr *)&(pcb->remote_ip))) == NULL) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_rexmit_segment: No route to 0x%lx\n", pcb->remote_ip.addr));
#ifdef TCP_STATS
++stats.tcp.rterr;
#endif /* TCP_STATS */
return;
}
seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
seg->tcphdr->wnd = htons(pcb->rcv_wnd);
/* Recalculate checksum. */
seg->tcphdr->chksum = 0;
#if CHECKSUM_GEN_TCP
seg->tcphdr->chksum = inet_chksum_pseudo(seg->p,
&(pcb->local_ip),
&(pcb->remote_ip),
IP_PROTO_TCP, seg->p->tot_len);
#endif
len = seg->p->len;
tot_len = seg->p->tot_len;
pbuf_header(seg->p, IP_HLEN);
ip_output_if(seg->p, NULL, IP_HDRINCL, TCP_TTL, IP_PROTO_TCP, netif);
seg->p->len = len;
seg->p->tot_len = tot_len;
seg->p->payload = seg->tcphdr;
#ifdef TCP_STATS
++stats.tcp.xmit;
++stats.tcp.rexmit;
#endif /* TCP_STATS */
pcb->rtime = 0;
/* Don't take any rtt measurements after retransmitting. */
pcb->rttest = 0;
} else {
DEBUGF(TCP_REXMIT_DEBUG, ("tcp_rexmit_seg: no room in window %lu to send %lu (ack %lu)\n",
wnd, ntohl(seg->tcphdr->seqno), pcb->lastack));
}
}
/** Get the tcplen (datalen + SYN/FIN) of all segments on the ooseq list
*
* @param pcb the pcb to check for ooseq segments
* @return tcplen of all segment
*/
static int
tcp_oos_tcplen(struct tcp_pcb* pcb)
{
int len = 0;
struct tcp_seg* seg = pcb->ooseq;
/* then check the actual segment */
while(seg != NULL) {
len += TCP_TCPLEN(seg);
seg = seg->next;
}
return len;
}
/** Get the tcplen (datalen + SYN/FIN) of a segment (by index) on the ooseq list
*
* @param pcb the pcb to check for ooseq segments
* @param seg_index index of the segment on the ooseq list
* @return tcplen of the segment
*/
static int
tcp_oos_seg_tcplen(struct tcp_pcb* pcb, int seg_index)
{
int num = 0;
struct tcp_seg* seg = pcb->ooseq;
/* then check the actual segment */
while(seg != NULL) {
if(num == seg_index) {
return TCP_TCPLEN(seg);
}
num++;
seg = seg->next;
}
fail();
return -1;
}
/* 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
s16_t 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 = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
seg = pcb->unsent;
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
/* If the TF_ACK_NOW flag is set and no data will be sent (either
* because the ->unsent queue is empty or because the window does
* not allow it), construct an empty ACK segment and send it.
*
* If data is to be sent, we will just piggyback the ACK (see below).
*/
if (pcb->flags & TF_ACK_NOW &&
(seg == NULL ||
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
if (p == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
return ERR_BUF;
}
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
/* remove ACK flags from the PCB, as we send an empty ACK now */
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
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_HDRLEN_SET(tcphdr, 5);
tcphdr->chksum = 0;
#if CHECKSUM_GEN_TCP
tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
IP_PROTO_TCP, p->tot_len);
#endif
ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
IP_PROTO_TCP);
pbuf_free(p);
return ERR_OK;
}
#if TCP_OUTPUT_DEBUG
if (seg == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n", (void*)pcb->unsent));
}
#endif /* TCP_OUTPUT_DEBUG */
#if TCP_CWND_DEBUG
if (seg == NULL) {
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", seg == NULL, ack %"U32_F"\n",
pcb->snd_wnd, pcb->cwnd, wnd,
pcb->lastack));
} else {
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\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 */
/* data available and window allows it to be sent? */
while (seg != NULL &&
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
#if TCP_CWND_DEBUG
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\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_SET_FLAG(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;
/* unacked list is empty? */
if (pcb->unacked == NULL) {
pcb->unacked = seg;
useg = seg;
/* unacked list is not empty? */
} else {
/* In the case of fast retransmit, the packet should not go to the tail
* of the unacked queue, but rather at the head. We need to check for
* this case. -STJ Jul 27, 2004 */
if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))){
/* add segment to head of unacked list */
seg->next = pcb->unacked;
pcb->unacked = seg;
} else {
/* add segment to tail of unacked list */
useg->next = seg;
useg = useg->next;
}
}
/* do not queue empty segments on the unacked list */
} else {
tcp_seg_free(seg);
}
seg = pcb->unsent;
}
return ERR_OK;
}
/**
* Enqueue either data or TCP options (but not both) for tranmission
*
*
*
* @arg pcb Protocol control block for the TCP connection to enqueue data for.
* @arg arg Pointer to the data to be enqueued for sending.
* @arg len Data length in bytes
* @arg flags
* @arg copy 1 if data must be copied, 0 if data is non-volatile and can be
* referenced.
* @arg optdata
* @arg optlen
*/
err_t
tcp_enqueue(struct tcp_pcb *pcb, void *arg, u16_t len,
u8_t flags, u8_t copy,
u8_t *optdata, u8_t optlen)
{
struct pbuf *p;
struct tcp_seg *seg, *useg, *queue;
u32_t left, seqno;
u16_t seglen;
void *ptr;
u8_t queuelen;
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue(pcb=%p, arg=%p, len=%"U16_F", flags=%"X16_F", copy=%"U16_F")\n",
(void *)pcb, arg, len, (u16_t)flags, (u16_t)copy));
LWIP_ASSERT("tcp_enqueue: len == 0 || optlen == 0 (programmer violates API)",
len == 0 || optlen == 0);
LWIP_ASSERT("tcp_enqueue: arg == NULL || optdata == NULL (programmer violates API)",
arg == NULL || optdata == NULL);
/* fail on too much data */
if (len > pcb->snd_buf) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n", len, pcb->snd_buf));
return ERR_MEM;
}
left = len;
ptr = arg;
/* seqno will be the sequence number of the first segment enqueued
* by the call to this function. */
seqno = pcb->snd_lbb;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
/* If total number of pbufs on the unsent/unacked queues exceeds the
* configured maximum, return an error */
queuelen = pcb->snd_queuelen;
if (queuelen >= TCP_SND_QUEUELEN) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too long queue %"U16_F" (max %"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
TCP_STATS_INC(tcp.memerr);
return ERR_MEM;
}
if (queuelen != 0) {
LWIP_ASSERT("tcp_enqueue: pbufs on queue => at least one queue non-empty",
pcb->unacked != NULL || pcb->unsent != NULL);
} else {
LWIP_ASSERT("tcp_enqueue: no pbufs on queue => both queues empty",
pcb->unacked == NULL && pcb->unsent == NULL);
}
/* First, break up the data into segments and tuck them together in
* the local "queue" variable. */
useg = queue = seg = NULL;
seglen = 0;
while (queue == NULL || left > 0) {
/* The segment length should be the MSS if the data to be enqueued
* is larger than the MSS. */
seglen = left > pcb->mss? pcb->mss: left;
/* Allocate memory for tcp_seg, and fill in fields. */
seg = memp_malloc(MEMP_TCP_SEG);
if (seg == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for tcp_seg\n"));
goto memerr;
}
seg->next = NULL;
seg->p = NULL;
/* first segment of to-be-queued data? */
if (queue == NULL) {
queue = seg;
}
/* subsequent segments of to-be-queued data */
else {
/* Attach the segment to the end of the queued segments */
LWIP_ASSERT("useg != NULL", useg != NULL);
useg->next = seg;
}
/* remember last segment of to-be-queued data for next iteration */
useg = seg;
/* If copy is set, memory should be allocated
* and data copied into pbuf, otherwise data comes from
* ROM or other static memory, and need not be copied. If
* optdata is != NULL, we have options instead of data. */
/* options? */
if (optdata != NULL) {
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
goto memerr;
}
++queuelen;
seg->dataptr = seg->p->payload;
}
/* copy from volatile memory? */
else if (copy) {
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
goto memerr;
}
++queuelen;
if (arg != NULL) {
memcpy(seg->p->payload, ptr, seglen);
}
seg->dataptr = seg->p->payload;
}
/* do not copy data */
else {
/* First, allocate a pbuf for holding the data.
* since the referenced data is available at least until it is sent out on the
* link (as it has to be ACKed by the remote party) we can safely use PBUF_ROM
* instead of PBUF_REF here.
*/
if ((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for zero-copy pbuf\n"));
goto memerr;
}
++queuelen;
/* reference the non-volatile payload data */
p->payload = ptr;
seg->dataptr = ptr;
/* Second, allocate a pbuf for the headers. */
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) {
/* If allocation fails, we have to deallocate the data pbuf as
* well. */
pbuf_free(p);
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for header pbuf\n"));
goto memerr;
}
++queuelen;
/* Concatenate the headers and data pbufs together. */
pbuf_cat(seg->p/*header*/, p/*data*/);
p = NULL;
}
/* Now that there are more segments queued, we check again if the
length of the queue exceeds the configured maximum. */
if (queuelen > TCP_SND_QUEUELEN) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
goto memerr;
}
seg->len = seglen;
/* build TCP header */
if (pbuf_header(seg->p, TCP_HLEN)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: no room for TCP header in pbuf.\n"));
TCP_STATS_INC(tcp.err);
goto memerr;
}
seg->tcphdr = seg->p->payload;
seg->tcphdr->src = htons(pcb->local_port);
seg->tcphdr->dest = htons(pcb->remote_port);
seg->tcphdr->seqno = htonl(seqno);
seg->tcphdr->urgp = 0;
TCPH_FLAGS_SET(seg->tcphdr, flags);
/* don't fill in tcphdr->ackno and tcphdr->wnd until later */
/* Copy the options into the header, if they are present. */
if (optdata == NULL) {
TCPH_HDRLEN_SET(seg->tcphdr, 5);
}
else {
TCPH_HDRLEN_SET(seg->tcphdr, (5 + optlen / 4));
/* Copy options into data portion of segment.
Options can thus only be sent in non data carrying
segments such as SYN|ACK. */
memcpy(seg->dataptr, optdata, optlen);
}
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE, ("tcp_enqueue: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
ntohl(seg->tcphdr->seqno),
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
(u16_t)flags));
left -= seglen;
seqno += seglen;
ptr = (void *)((u8_t *)ptr + seglen);
}
/* Now that the data to be enqueued has been broken up into TCP
segments in the queue variable, we add them to the end of the
pcb->unsent queue. */
if (pcb->unsent == NULL) {
useg = NULL;
}
else {
for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
}
/* { useg is last segment on the unsent queue, NULL if list is empty } */
/* If there is room in the last pbuf on the unsent queue,
chain the first pbuf on the queue together with that. */
if (useg != NULL &&
TCP_TCPLEN(useg) != 0 &&
!(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) &&
!(flags & (TCP_SYN | TCP_FIN)) &&
/* fit within max seg size */
useg->len + queue->len <= pcb->mss) {
/* Remove TCP header from first segment of our to-be-queued list */
pbuf_header(queue->p, -TCP_HLEN);
pbuf_cat(useg->p, queue->p);
useg->len += queue->len;
useg->next = queue->next;
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE | DBG_STATE, ("tcp_enqueue: chaining segments, new len %"U16_F"\n", useg->len));
if (seg == queue) {
seg = NULL;
}
memp_free(MEMP_TCP_SEG, queue);
}
else {
/* empty list */
if (useg == NULL) {
/* initialize list with this segment */
pcb->unsent = queue;
}
/* enqueue segment */
else {
useg->next = queue;
}
}
if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
++len;
}
pcb->snd_lbb += len;
pcb->snd_buf -= len;
/* update number of segments on the queues */
pcb->snd_queuelen = queuelen;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_enqueue: valid queue length",
pcb->unacked != NULL || pcb->unsent != NULL);
}
/* Set the PSH flag in the last segment that we enqueued, but only
if the segment has data (indicated by seglen > 0). */
if (seg != NULL && seglen > 0 && seg->tcphdr != NULL) {
TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
}
return ERR_OK;
memerr:
TCP_STATS_INC(tcp.memerr);
if (queue != NULL) {
tcp_segs_free(queue);
}
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
LWIP_DEBUGF(TCP_QLEN_DEBUG | DBG_STATE, ("tcp_enqueue: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
return ERR_MEM;
}
/* 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 = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
seg = pcb->unsent;
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
/* 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_IP, TCP_HLEN, PBUF_RAM);
if (p == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
return ERR_BUF;
}
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: sending ACK for %lu\n", pcb->rcv_nxt));
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_HDRLEN_SET(tcphdr, 5);
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), pcb->ttl, pcb->tos,
IP_PROTO_TCP);
pbuf_free(p);
return ERR_OK;
}
#if TCP_OUTPUT_DEBUG
if (seg == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n", pcb->unsent));
}
#endif /* TCP_OUTPUT_DEBUG */
#if TCP_CWND_DEBUG
if (seg == NULL) {
LWIP_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 {
LWIP_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) {
#if TCP_CWND_DEBUG
LWIP_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_SET_FLAG(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;
useg = seg;
} else {
useg->next = seg;
useg = useg->next;
}
} else {
tcp_seg_free(seg);
}
seg = pcb->unsent;
}
return ERR_OK;
}
/**
* Called by tcp_process. Checks if the given segment is an ACK for outstanding
* data, and if so frees the memory of the buffered data. Next, is places the
* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
* i it has been removed from the buffer.
*
* If the incoming segment constitutes an ACK for a segment that was used for RTT
* estimation, the RTT is estimated here as well.
*
* Called from tcp_process().
*
* @return 1 if the incoming segment is the next in sequence, 0 if not
*/
static u8_t
tcp_receive(struct tcp_pcb *pcb)
{
struct tcp_seg *next;
#if TCP_QUEUE_OOSEQ
struct tcp_seg *prev, *cseg;
#endif
struct pbuf *p;
s32_t off;
s16_t m;
u32_t right_wnd_edge;
u16_t new_tot_len;
u8_t accepted_inseq = 0;
if (flags & TCP_ACK) {
right_wnd_edge = pcb->snd_wnd + pcb->snd_wl1;
/* Update window. */
if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
pcb->snd_wnd = tcphdr->wnd;
pcb->snd_wl1 = seqno;
pcb->snd_wl2 = ackno;
if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
pcb->persist_backoff = 0;
}
LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
#if TCP_WND_DEBUG
} else {
if (pcb->snd_wnd != tcphdr->wnd) {
LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: no window update lastack %"U32_F" snd_max %"U32_F" ackno %"U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
pcb->lastack, pcb->snd_max, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
}
#endif /* TCP_WND_DEBUG */
}
if (pcb->lastack == ackno) {
pcb->acked = 0;
if (pcb->snd_wl1 + pcb->snd_wnd == right_wnd_edge){
++pcb->dupacks;
if (pcb->dupacks >= 3 && pcb->unacked != NULL) {
if (!(pcb->flags & TF_INFR)) {
/* This is fast retransmit. Retransmit the first unacked segment. */
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %"U16_F" (%"U32_F"), fast retransmit %"U32_F"\n",
(u16_t)pcb->dupacks, pcb->lastack,
ntohl(pcb->unacked->tcphdr->seqno)));
tcp_rexmit(pcb);
/* Set ssthresh to max (FlightSize / 2, 2*SMSS) */
/*pcb->ssthresh = LWIP_MAX((pcb->snd_max -
pcb->lastack) / 2,
2 * pcb->mss);*/
/* Set ssthresh to half of the minimum of the current cwnd and the advertised window */
if (pcb->cwnd > pcb->snd_wnd)
pcb->ssthresh = pcb->snd_wnd / 2;
else
pcb->ssthresh = pcb->cwnd / 2;
/* The minimum value for ssthresh should be 2 MSS */
if (pcb->ssthresh < 2*pcb->mss) {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: The minimum value for ssthresh %"U16_F" should be min 2 mss %"U16_F"...\n", pcb->ssthresh, 2*pcb->mss));
pcb->ssthresh = 2*pcb->mss;
}
pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
pcb->flags |= TF_INFR;
} else {
/* Inflate the congestion window, but not if it means that
the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
}
}
} else {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupack averted %"U32_F" %"U32_F"\n",
pcb->snd_wl1 + pcb->snd_wnd, right_wnd_edge));
}
} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_max)){
/* We come here when the ACK acknowledges new data. */
/* Reset the "IN Fast Retransmit" flag, since we are no longer
in fast retransmit. Also reset the congestion window to the
slow start threshold. */
if (pcb->flags & TF_INFR) {
pcb->flags &= ~TF_INFR;
pcb->cwnd = pcb->ssthresh;
}
/* Reset the number of retransmissions. */
pcb->nrtx = 0;
/* Reset the retransmission time-out. */
pcb->rto = (pcb->sa >> 3) + pcb->sv;
/* Update the send buffer space. Diff between the two can never exceed 64K? */
pcb->acked = (u16_t)(ackno - pcb->lastack);
pcb->snd_buf += pcb->acked;
/* Reset the fast retransmit variables. */
pcb->dupacks = 0;
pcb->lastack = ackno;
/* Update the congestion control variables (cwnd and
ssthresh). */
if (pcb->state >= ESTABLISHED) {
if (pcb->cwnd < pcb->ssthresh) {
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
} else {
u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
if (new_cwnd > pcb->cwnd) {
pcb->cwnd = new_cwnd;
}
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
}
}
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
ackno,
pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno): 0,
pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
/* Remove segment from the unacknowledged list if the incoming
ACK acknowlegdes them. */
while (pcb->unacked != NULL &&
TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked), ackno)) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
ntohl(pcb->unacked->tcphdr->seqno),
ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked)));
next = pcb->unacked;
pcb->unacked = pcb->unacked->next;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
pcb->snd_queuelen -= pbuf_clen(next->p);
tcp_seg_free(next);
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
}
/* If there's nothing left to acknowledge, stop the retransmit
timer, otherwise reset it to start again */
if(pcb->unacked == NULL)
pcb->rtime = -1;
else
pcb->rtime = 0;
pcb->polltmr = 0;
} else {
err_t tcp_enqueue (
struct tcp_pcb* pcb, void* arg, u16_t len,
u8_t flags, u8_t copy,
u8_t* optdata, u8_t optlen
) {
struct pbuf* p;
struct tcp_seg* seg, *useg, *queue;
u32_t left, seqno;
u16_t seglen;
void* ptr;
u8_t queuelen;
flags_t lPCBFlags = pcb -> flags;
int iSegCNT = 0;
left = len;
ptr = arg;
if ( len > pcb -> snd_buf ) return ERR_MEM;
seqno = pcb -> snd_lbb;
queue = NULL;
queuelen = pcb -> snd_queuelen;
if ( queuelen >= TCP_SND_QUEUELEN ) goto memerr;
seg = useg = NULL;
seglen = 0;
while ( !queue || left > 0 ) {
if ( lPCBFlags & TF_EVENSEG ) {
++iSegCNT;
seglen = left > pcb -> mss ? pcb -> mss
: (((iSegCNT%2) == 1)? ((left + 1) / 2): left);
} else seglen = left > pcb -> mss ? pcb -> mss : left;
seg = memp_malloc ( MEMP_TCP_SEG );
if ( !seg ) goto memerr;
seg -> next = NULL;
seg -> p = NULL;
if ( !queue )
useg = queue = seg;
else {
useg -> next = seg;
useg = seg;
} /* end else */
if (optdata != NULL) {
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
goto memerr;
}
++queuelen;
seg->dataptr = seg->p->payload;
}
else if (copy) {
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue : could not allocate memory for pbuf copy size %u\n", seglen));
goto memerr;
}
++queuelen;
if (arg != NULL) {
mips_memcpy(seg->p->payload, ptr, seglen);
}
seg->dataptr = seg->p->payload;
}
/* do not copy data */
else {
/* first, allocate a pbuf for holding the data.
* since the referenced data is available at least until it is sent out on the
* link (as it has to be ACKed by the remote party) we can safely use PBUF_ROM
* instead of PBUF_REF here.
*/
if ((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for zero-copy pbuf\n"));
goto memerr;
}
++queuelen;
p->payload = ptr;
seg->dataptr = ptr;
/* Second, allocate a pbuf for the headers. */
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) {
/* If allocation fails, we have to deallocate the data pbuf as
* well. */
pbuf_free(p);
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for header pbuf\n"));
goto memerr;
}
++queuelen;
/* Concatenate the headers and data pbufs together. */
pbuf_cat(seg->p, p);
p = NULL;
}
/* Now that there are more segments queued, we check again if the
length of the queue exceeds the configured maximum. */
if (queuelen > TCP_SND_QUEUELEN) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: queue too long %u (%u)\n", queuelen, TCP_SND_QUEUELEN));
goto memerr;
}
seg->len = seglen;
if (pbuf_header(seg->p, TCP_HLEN)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: no room for TCP header in pbuf.\n"));
TCP_STATS_INC(tcp.err);
goto memerr;
}
seg->tcphdr = seg->p->payload;
seg->tcphdr->src = htons(pcb->local_port);
seg->tcphdr->dest = htons(pcb->remote_port);
seg->tcphdr->seqno = htonl(seqno);
seg->tcphdr->urgp = 0;
TCPH_FLAGS_SET(seg->tcphdr, flags);
/* don't fill in tcphdr->ackno and tcphdr->wnd until later */
/* Copy the options into the header, if they are present. */
if (optdata == NULL) {
TCPH_HDRLEN_SET(seg->tcphdr, 5);
}
else {
TCPH_HDRLEN_SET(seg->tcphdr, (5 + optlen / 4));
/* Copy options into data portion of segment.
Options can thus only be sent in non data carrying
segments such as SYN|ACK. */
mips_memcpy(seg->dataptr, optdata, optlen);
}
left -= seglen;
seqno += seglen;
ptr = (void *)((char *)ptr + seglen);
}
/* Now that the data to be enqueued has been broken up into TCP
segments in the queue variable, we add them to the end of the
pcb->unsent queue. */
if (pcb->unsent == NULL) {
useg = NULL;
}
else {
for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
}
/* If there is room in the last pbuf on the unsent queue,
chain the first pbuf on the queue together with that. */
if (useg != NULL &&
TCP_TCPLEN(useg) != 0 &&
!(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) &&
!(flags & (TCP_SYN | TCP_FIN)) &&
useg->len + queue->len <= pcb->mss) {
/* Remove TCP header from first segment. */
pbuf_header(queue->p, -TCP_HLEN);
pbuf_cat(useg->p, queue->p);
useg->len += queue->len;
useg->next = queue->next;
if (seg == queue) seg = NULL;
memp_free(MEMP_TCP_SEG, queue);
}
else {
if (useg == NULL) {
pcb->unsent = queue;
}
else {
useg->next = queue;
}
}
if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
++len;
}
pcb->snd_lbb += len;
pcb->snd_buf -= len;
pcb->snd_queuelen = queuelen;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %d (after enqueued)\n", pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
/* Set the PSH flag in the last segment that we enqueued, but only
if the segment has data (indicated by seglen > 0). */
if (seg != NULL && seglen > 0 && seg->tcphdr != NULL) {
TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
}
return ERR_OK;
memerr:
TCP_STATS_INC(tcp.memerr);
if (queue != NULL) {
tcp_segs_free(queue);
}
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
LWIP_DEBUGF(TCP_QLEN_DEBUG | DBG_STATE, ("tcp_enqueue: %d (with mem err)\n", pcb->snd_queuelen));
return ERR_MEM;
}
/**
* Find out what we can send and send it
*
* @param pcb Protocol control block for the TCP connection to send data
* @return ERR_OK if data has been sent or nothing to send
* another err_t on error
*/
err_t
tcp_output(struct tcp_pcb *pcb)
{
struct tcp_seg *seg, *useg;
u32_t wnd, snd_nxt;
#if TCP_CWND_DEBUG
s16_t 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 = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U32_F
", wnd %"U32_F"\n",pcb->snd_wnd, pcb->cwnd, wnd ));
seg = pcb->unsent;
/* If the TF_ACK_NOW flag is set and no data will be sent (either
* because the ->unsent queue is empty or because the window does
* not allow it), construct an empty ACK segment and send it.
*
* If data is to be sent, we will just piggyback the ACK (see below).
*/
if (pcb->flags & TF_ACK_NOW &&
(seg == NULL ||
seg->seqno - pcb->lastack + seg->len > wnd)) {
return tcp_send_empty_ack(pcb);
}
#if TCP_OUTPUT_DEBUG
if (seg == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
(void*)pcb->unsent));
}
#endif /* TCP_OUTPUT_DEBUG */
#if TCP_CWND_DEBUG
if (seg == NULL) {
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F
", cwnd %"U32_F", wnd %"U32_F
", seg == NULL, ack %"U32_F"\n",
pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
} else {
LWIP_DEBUGF(TCP_CWND_DEBUG,
("tcp_output: snd_wnd %"U32_F", cwnd %"U32_F", wnd %"U32_F
", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\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 */
/* data available and window allows it to be sent? */
while (seg != NULL &&
seg->seqno - pcb->lastack + seg->len <= wnd) {
LWIP_ASSERT("RST not expected here!",
(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
/* Stop sending if the nagle algorithm would prevent it
* Don't stop:
* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
* either seg->next != NULL or pcb->unacked == NULL;
* RST is no sent using tcp_write/tcp_output.
*/
if((tcp_do_output_nagle(pcb) == 0) &&
((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)){
if ( pcb->snd_sml_snt > (pcb->unacked ? pcb->unacked->len : 0) ) {
break;
}
else {
if ( (u32_t)((seg->next ? seg->next->len : 0) + seg->len) <= pcb->snd_sml_add ) {
pcb->snd_sml_snt = pcb->snd_sml_add;
}
}
}
#if TCP_CWND_DEBUG
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\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 (get_tcp_state(pcb) != SYN_SENT) {
TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
}
#if TCP_OVERSIZE_DBGCHECK
seg->oversize_left = 0;
#endif /* TCP_OVERSIZE_DBGCHECK */
tcp_output_segment(seg, pcb);
snd_nxt = seg->seqno + TCP_TCPLEN(seg);
if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
pcb->snd_nxt = snd_nxt;
}
/* put segment on unacknowledged list if length > 0 */
if (TCP_TCPLEN(seg) > 0) {
seg->next = NULL;
/* unacked list is empty? */
if (pcb->unacked == NULL) {
pcb->unacked = seg;
pcb->last_unacked = seg;
/* unacked list is not empty? */
} else {
/* In the case of fast retransmit, the packet should not go to the tail
* of the unacked queue, but rather somewhere before it. We need to check for
* this case. -STJ Jul 27, 2004 */
useg = pcb->last_unacked;
if (TCP_SEQ_LT(seg->seqno, useg->seqno)) {
/* add segment to before tail of unacked list, keeping the list sorted */
struct tcp_seg **cur_seg = &(pcb->unacked);
while (*cur_seg &&
TCP_SEQ_LT((*cur_seg)->seqno, seg->seqno)) {
cur_seg = &((*cur_seg)->next );
}
LWIP_ASSERT("Value of last_unacked is invalid",
*cur_seg != pcb->last_unacked->next);
seg->next = (*cur_seg);
(*cur_seg) = seg;
} else {
/* add segment to tail of unacked list */
useg->next = seg;
pcb->last_unacked = seg;
}
}
/* do not queue empty segments on the unacked list */
} else {
tcp_tx_seg_free(pcb, seg);
}
seg = pcb->unsent;
}
#if TCP_OVERSIZE
if (pcb->unsent == NULL) {
/* last unsent has been removed, reset unsent_oversize */
pcb->unsent_oversize = 0;
}
#endif /* TCP_OVERSIZE */
pcb->flags &= ~TF_NAGLEMEMERR;
return ERR_OK;
}
/**
* Enqueue TCP options for transmission.
*
* Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
*
* @param pcb Protocol control block for the TCP connection.
* @param flags TCP header flags to set in the outgoing segment.
* @param optdata pointer to TCP options, or NULL.
* @param optlen length of TCP options in bytes.
*/
err_t
tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
{
struct pbuf *p;
struct tcp_seg *seg;
u8_t optflags = 0;
u8_t optlen = 0;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
(flags & (TCP_SYN | TCP_FIN)) != 0);
/* check for configured max queuelen and possible overflow (FIN flag should always come through!)*/
if (((pcb->snd_queuelen >= pcb->max_unsent_len) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) &&
((flags & TCP_FIN) == 0)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
pcb->snd_queuelen, pcb->max_unsent_len));
TCP_STATS_INC(tcp.memerr);
pcb->flags |= TF_NAGLEMEMERR;
return ERR_MEM;
}
if (flags & TCP_SYN) {
optflags = TF_SEG_OPTS_MSS;
if(enable_wnd_scale) optflags |= TF_SEG_OPTS_WNDSCALE;
#if LWIP_TCP_TIMESTAMPS
if (pcb->enable_ts_opt && !(flags & TCP_ACK)) {
// enable initial timestamp announcement only for the connecting side. accepting side reply accordingly.
optflags |= TF_SEG_OPTS_TS;
}
#endif
}
#if LWIP_TCP_TIMESTAMPS
if ((pcb->flags & TF_TIMESTAMP)) {
optflags |= TF_SEG_OPTS_TS;
}
#endif /* LWIP_TCP_TIMESTAMPS */
optlen = LWIP_TCP_OPT_LENGTH(optflags);
/* tcp_enqueue_flags is always called with either SYN or FIN in flags.
* We need one available snd_buf byte to do that.
* This means we can't send FIN while snd_buf==0. A better fix would be to
* not include SYN and FIN sequence numbers in the snd_buf count. */
/*if (pcb->snd_buf == 0) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: no send buffer available\n"));
TCP_STATS_INC(tcp.memerr);
return ERR_MEM;
}*/ //to consider snd_buf for syn or fin, unmarked sections with SND_BUF_FOR_SYN_FIN
/* Allocate pbuf with room for TCP header + options */
if ((p = tcp_tx_pbuf_alloc(pcb, optlen, PBUF_RAM)) == NULL) {
pcb->flags |= TF_NAGLEMEMERR;
TCP_STATS_INC(tcp.memerr);
return ERR_MEM;
}
LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
(p->len >= optlen));
/* Allocate memory for tcp_seg, and fill in fields. */
if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
pcb->flags |= TF_NAGLEMEMERR;
TCP_STATS_INC(tcp.memerr);
return ERR_MEM;
}
LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
ntohl(seg->tcphdr->seqno),
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
(u16_t)flags));
/* Now append seg to pcb->unsent queue */
if (pcb->unsent == NULL) {
pcb->unsent = seg;
} else {
struct tcp_seg *useg;
for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
useg->next = seg;
}
#if TCP_OVERSIZE
/* The new unsent tail has no space */
pcb->unsent_oversize = 0;
#endif /* TCP_OVERSIZE */
/* SYN and FIN bump the sequence number */
if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
pcb->snd_lbb++;
/* optlen does not influence snd_buf */
// pcb->snd_buf--; SND_BUF_FOR_SYN_FIN
}
if (flags & TCP_FIN) {
pcb->flags |= TF_FIN;
}
/* update number of segments on the queues */
pcb->snd_queuelen += pbuf_clen(seg->p);
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
pcb->unacked != NULL || pcb->unsent != NULL);
}
return ERR_OK;
}
/**
* Create a TCP segment with prefilled header.
*
* Called by tcp_write and tcp_enqueue_flags.
*
* @param pcb Protocol control block for the TCP connection.
* @param p pbuf that is used to hold the TCP header.
* @param flags TCP flags for header.
* @param seqno TCP sequence number of this packet
* @param optflags options to include in TCP header
* @return a new tcp_seg pointing to p, or NULL.
* The TCP header is filled in except ackno and wnd.
* p is freed on failure.
*/
static struct tcp_seg *
tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
{
struct tcp_seg *seg;
u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
#if LWIP_3RD_PARTY_BUFS
if ((seg = external_tcp_seg_alloc(pcb)) == NULL) {
#else
if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
#endif
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
tcp_tx_pbuf_free(pcb, p);
return NULL;
}
seg->flags = optflags;
seg->next = NULL;
seg->p = p;
seg->dataptr = p->payload;
seg->len = p->tot_len - optlen;
#if TCP_OVERSIZE_DBGCHECK
seg->oversize_left = 0;
#endif /* TCP_OVERSIZE_DBGCHECK */
#if TCP_CHECKSUM_ON_COPY
seg->chksum = 0;
seg->chksum_swapped = 0;
/* check optflags */
LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
#endif /* TCP_CHECKSUM_ON_COPY */
seg->seqno = seqno;
/* build TCP header */
if (pbuf_header(p, TCP_HLEN)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
TCP_STATS_INC(tcp.err);
tcp_tx_seg_free(pcb, seg);
return NULL;
}
seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
seg->tcphdr->src = htons(pcb->local_port);
seg->tcphdr->dest = htons(pcb->remote_port);
seg->tcphdr->seqno = htonl(seqno);
/* ackno is set in tcp_output */
TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
/* wnd and chksum are set in tcp_output */
seg->tcphdr->urgp = 0;
return seg;
}
/**
* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
*
* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
* there may be extra bytes available at the end.
*
* @param layer flag to define header size.
* @param length size of the pbuf's payload.
* @param max_length maximum usable size of payload+oversize.
* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
* @param pcb The TCP connection that willo enqueue the pbuf.
* @param apiflags API flags given to tcp_write.
* @param first_seg true when this pbuf will be used in the first enqueued segment.
* @param
*/
static struct pbuf *
tcp_pbuf_prealloc(u16_t length, u16_t max_length,
u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
u8_t first_seg)
{
struct pbuf *p;
u16_t alloc = length;
if (length < max_length) {
/* Should we allocate an oversized pbuf, or just the minimum
* length required? If tcp_write is going to be called again
* before this segment is transmitted, we want the oversized
* buffer. If the segment will be transmitted immediately, we can
* save memory by allocating only length. We use a simple
* heuristic based on the following information:
*
* Did the user set TCP_WRITE_FLAG_MORE?
*
* Will the Nagle algorithm defer transmission of this segment?
*/
if ((apiflags & TCP_WRITE_FLAG_MORE) ||
(!(pcb->flags & TF_NODELAY) &&
(!first_seg ||
pcb->unsent != NULL ||
pcb->unacked != NULL))) {
alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + pcb->tcp_oversize_val));
}
}
p = tcp_tx_pbuf_alloc(pcb, alloc, PBUF_RAM);
if (p == NULL) {
return NULL;
}
LWIP_ASSERT("need unchained pbuf", p->next == NULL);
*oversize = p->len - length;
/* trim p->len to the currently used size */
p->len = p->tot_len = length;
return p;
}
/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
*
* @param pcb the tcp pcb to check for
* @param len length of data to send (checked agains snd_buf)
* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
*/
static err_t
tcp_write_checks(struct tcp_pcb *pcb, u32_t len)
{
/* connection is in invalid state for data transmission? */
if ((get_tcp_state(pcb) != ESTABLISHED) &&
(get_tcp_state(pcb) != CLOSE_WAIT) &&
(get_tcp_state(pcb) != SYN_SENT) &&
(get_tcp_state(pcb) != SYN_RCVD)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
return ERR_CONN;
} else if (len == 0) {
return ERR_OK;
}
/* fail on too much data */
if (len > pcb->snd_buf) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U32_F" > snd_buf=%"U32_F")\n",
len, pcb->snd_buf));
pcb->flags |= TF_NAGLEMEMERR;
return ERR_MEM;
}
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U32_F"\n", (u32_t)pcb->snd_queuelen));
/* If total number of pbufs on the unsent/unacked queues exceeds the
* configured maximum, return an error */
/* check for configured max queuelen and possible overflow */
if ((pcb->snd_queuelen >= pcb->max_unsent_len) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U32_F" (max %"U32_F")\n",
pcb->snd_queuelen, pcb->max_unsent_len));
TCP_STATS_INC(tcp.memerr);
pcb->flags |= TF_NAGLEMEMERR;
return ERR_MEM;
}
if (pcb->snd_queuelen != 0) {
} else {
LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
pcb->unacked == NULL && pcb->unsent == NULL);
}
return ERR_OK;
}
/**
* Write data for sending (but does not send it immediately).
*
* It waits in the expectation of more data being sent soon (as
* it can send them more efficiently by combining them together).
* To prompt the system to send data now, call tcp_output() after
* calling tcp_write().
*
* @param pcb Protocol control block for the TCP connection to enqueue data for.
* @param arg Pointer to the data to be enqueued for sending.
* @param len Data length in bytes
* @param apiflags combination of following flags :
* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
* @return ERR_OK if enqueued, another err_t on error
*/
err_t
tcp_write(struct tcp_pcb *pcb, const void *arg, u32_t len, u8_t apiflags)
{
struct pbuf *concat_p = NULL;
struct tcp_seg *seg = NULL, *prev_seg = NULL, *queue = NULL;
u32_t pos = 0; /* position in 'arg' data */
u32_t queuelen;
u8_t optlen = 0;
u8_t optflags = 0;
#if TCP_OVERSIZE
u16_t oversize = 0;
u16_t oversize_used = 0;
#endif /* TCP_OVERSIZE */
#if TCP_CHECKSUM_ON_COPY
u16_t concat_chksum = 0;
u8_t concat_chksum_swapped = 0;
u16_t concat_chksummed = 0;
#endif /* TCP_CHECKSUM_ON_COPY */
err_t err;
/* don't allocate segments bigger than half the maximum window we ever received */
u16_t mss_local = LWIP_MIN(pcb->mss, pcb->snd_wnd_max/2);
mss_local = mss_local ? mss_local : pcb->mss;
int byte_queued = pcb->snd_nxt - pcb->lastack;
if ( len < pcb->mss)
pcb->snd_sml_add = (pcb->unacked ? pcb->unacked->len : 0) + byte_queued;
#if LWIP_NETIF_TX_SINGLE_PBUF
/* Always copy to try to create single pbufs for TX */
apiflags |= TCP_WRITE_FLAG_COPY;
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
(void *)pcb, arg, len, (u16_t)apiflags));
LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
arg != NULL, return ERR_ARG;);
err = tcp_write_checks(pcb, len);
if (err != ERR_OK) {
return err;
}
queuelen = pcb->snd_queuelen;
#if LWIP_TCP_TIMESTAMPS
if ((pcb->flags & TF_TIMESTAMP)) {
optflags = TF_SEG_OPTS_TS;
/* ensure that segments can hold at least one data byte... */
mss_local = LWIP_MAX(mss_local, LWIP_TCP_OPT_LEN_TS + 1);
}
#endif /* LWIP_TCP_TIMESTAMPS */
optlen = LWIP_TCP_OPT_LENGTH( optflags );
/*
* TCP segmentation is done in three phases with increasing complexity:
*
* 1. Copy data directly into an oversized pbuf.
* 2. Chain a new pbuf to the end of pcb->unsent.
* 3. Create new segments.
*
* We may run out of memory at any point. In that case we must
* return ERR_MEM and not change anything in pcb. Therefore, all
* changes are recorded in local variables and committed at the end
* of the function. Some pcb fields are maintained in local copies:
*
* queuelen = pcb->snd_queuelen
* oversize = pcb->unsent_oversize
*
* These variables are set consistently by the phases:
*
* seg points to the last segment tampered with.
*
* pos records progress as data is segmented.
*/
/* Find the tail of the unsent queue. */
if (pcb->unsent != NULL) {
u16_t space;
u16_t unsent_optlen;
if (!pcb->last_unsent || pcb->last_unsent->next) {
/* @todo: this could be sped up by keeping last_unsent in the pcb */
for (pcb->last_unsent = pcb->unsent; pcb->last_unsent->next != NULL;
pcb->last_unsent = pcb->last_unsent->next);
}
/* Usable space at the end of the last unsent segment */
unsent_optlen = LWIP_TCP_OPT_LENGTH(pcb->last_unsent->flags);
LWIP_ASSERT("mss_local is too small", mss_local >= pcb->last_unsent->len + unsent_optlen);
space = mss_local - (pcb->last_unsent->len + unsent_optlen);
/*
* Phase 1: Copy data directly into an oversized pbuf.
*
* The number of bytes copied is recorded in the oversize_used
* variable. The actual copying is done at the bottom of the
* function.
*/
#if TCP_OVERSIZE
#if TCP_OVERSIZE_DBGCHECK
/* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
pcb->unsent_oversize == pcb->last_unsent->oversize_left);
#endif /* TCP_OVERSIZE_DBGCHECK */
oversize = pcb->unsent_oversize;
if (oversize > 0) {
LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
seg = pcb->last_unsent;
oversize_used = oversize < len ? oversize : len;
pos += oversize_used;
oversize -= oversize_used;
space -= oversize_used;
}
/* now we are either finished or oversize is zero */
LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
#endif /* TCP_OVERSIZE */
/*
* Phase 2: Chain a new pbuf to the end of pcb->unsent.
*
* We don't extend segments containing SYN/FIN flags or options
* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
* the end.
*/
if ((pos < len) && (space > 0) && (pcb->last_unsent->len > 0)) {
u16_t seglen = space < len - pos ? space : len - pos;
seg = pcb->last_unsent;
/* Create a pbuf with a copy or reference to seglen bytes. We
* can use PBUF_RAW here since the data appears in the middle of
* a segment. A header will never be prepended. */
if (apiflags & TCP_WRITE_FLAG_COPY) {
/* Data is copied */
if ((concat_p = tcp_pbuf_prealloc(seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
seglen));
goto memerr;
}
#if TCP_OVERSIZE_DBGCHECK
pcb->last_unsent->oversize_left += oversize;
#endif /* TCP_OVERSIZE_DBGCHECK */
TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
#if TCP_CHECKSUM_ON_COPY
concat_chksummed += seglen;
#endif /* TCP_CHECKSUM_ON_COPY */
} else {
LWIP_ASSERT("tcp_write : we are never here", 0);
goto memerr;
}
pos += seglen;
queuelen += pbuf_clen(concat_p);
}
} else {
#if TCP_OVERSIZE
pcb->last_unsent = NULL;
LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
pcb->unsent_oversize == 0);
#endif /* TCP_OVERSIZE */
}
/*
* Phase 3: Create new segments.
*
* The new segments are chained together in the local 'queue'
* variable, ready to be appended to pcb->unsent.
*/
while (pos < len) {
struct pbuf *p;
u32_t left = len - pos;
u16_t max_len = mss_local - optlen;
u16_t seglen = left > max_len ? max_len : left;
if (apiflags & TCP_WRITE_FLAG_COPY) {
/* If copy is set, memory should be allocated and data copied
* into pbuf */
if ((p = tcp_pbuf_prealloc(seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
goto memerr;
}
LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
(p->len >= seglen));
TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
} else {
LWIP_ASSERT("tcp_write: we are never here",0);
goto memerr;
}
queuelen += pbuf_clen(p);
/* Now that there are more segments queued, we check again if the
* length of the queue exceeds the configured maximum or
* overflows. */
if ((queuelen > pcb->max_unsent_len) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U32_F" (%"U32_F")\n", queuelen, pcb->max_unsent_len));
tcp_tx_pbuf_free(pcb, p);
goto memerr;
}
if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
goto memerr;
}
#if TCP_OVERSIZE_DBGCHECK
seg->oversize_left = oversize;
#endif /* TCP_OVERSIZE_DBGCHECK */
#if TCP_CHECKSUM_ON_COPY
seg->chksum = chksum;
seg->chksum_swapped = chksum_swapped;
seg->flags |= TF_SEG_DATA_CHECKSUMMED;
#endif /* TCP_CHECKSUM_ON_COPY */
/* Fix dataptr for the nocopy case */
if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
seg->dataptr = (u8_t*)arg + pos;
}
/* first segment of to-be-queued data? */
if (queue == NULL) {
queue = seg;
} else {
/* Attach the segment to the end of the queued segments */
LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
prev_seg->next = seg;
}
/* remember last segment of to-be-queued data for next iteration */
prev_seg = seg;
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
ntohl(seg->tcphdr->seqno),
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
pos += seglen;
}
/*
* All three segmentation phases were successful. We can commit the
* transaction.
*/
/*
* Phase 1: If data has been added to the preallocated tail of
* last_unsent, we update the length fields of the pbuf chain.
*/
#if TCP_OVERSIZE
if (oversize_used > 0) {
struct pbuf *p;
/* Bump tot_len of whole chain, len of tail */
for (p = pcb->last_unsent->p; p; p = p->next) {
p->tot_len += oversize_used;
if (p->next == NULL) {
TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, pcb->last_unsent);
p->len += oversize_used;
}
}
pcb->last_unsent->len += oversize_used;
#if TCP_OVERSIZE_DBGCHECK
pcb->last_unsent->oversize_left -= oversize_used;
#endif /* TCP_OVERSIZE_DBGCHECK */
}
pcb->unsent_oversize = oversize;
#endif /* TCP_OVERSIZE */
/*
* Phase 2: concat_p can be concatenated onto pcb->last_unsent->p
*/
if (concat_p != NULL) {
LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
(pcb->last_unsent != NULL));
pbuf_cat(pcb->last_unsent->p, concat_p);
pcb->last_unsent->len += concat_p->tot_len;
#if TCP_CHECKSUM_ON_COPY
if (concat_chksummed) {
tcp_seg_add_chksum(concat_chksum, concat_chksummed, &pcb->last_unsent->chksum,
&pcb->last_unsent->chksum_swapped);
pcb->last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
}
#endif /* TCP_CHECKSUM_ON_COPY */
}
/*
* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
* is harmless
*/
if (pcb->last_unsent == NULL) {
pcb->unsent = queue;
} else {
pcb->last_unsent->next = queue;
}
pcb->last_unsent = seg;
/*
* Finally update the pcb state.
*/
pcb->snd_lbb += len;
pcb->snd_buf -= len;
pcb->snd_queuelen = queuelen;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_write: valid queue length",
pcb->unacked != NULL || pcb->unsent != NULL);
}
/* Set the PSH flag in the last segment that we enqueued. */
if (seg != NULL && seg->tcphdr != NULL) {
TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
}
return ERR_OK;
memerr:
pcb->flags |= TF_NAGLEMEMERR;
TCP_STATS_INC(tcp.memerr);
if (concat_p != NULL) {
tcp_tx_pbuf_free(pcb, concat_p);
}
if (queue != NULL) {
tcp_tx_segs_free(pcb, queue);
}
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
return ERR_MEM;
}
/*-----------------------------------------------------------------------------------*/
err_t
tcp_enqueue(struct tcp_pcb *pcb, void *arg, u16_t len,
u8_t flags, u8_t copy,
u8_t *optdata, u8_t optlen)
{
struct pbuf *p;
struct tcp_seg *seg, *useg, *queue;
u32_t left, seqno;
u16_t seglen;
void *ptr;
u8_t queuelen;
left = len;
ptr = arg;
if(len > pcb->snd_buf) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: too much data %d\n", len));
return ERR_MEM;
}
seqno = pcb->snd_lbb;
queue = NULL;
DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %d\n", pcb->snd_queuelen));
queuelen = pcb->snd_queuelen;
if(queuelen >= TCP_SND_QUEUELEN) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: too long queue %d (max %d)\n", queuelen, TCP_SND_QUEUELEN));
goto memerr;
}
#ifdef LWIP_DEBUG
if(pcb->snd_queuelen != 0) {
ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
#endif /* LWIP_DEBUG */
seg = NULL;
seglen = 0;
while(queue == NULL || left > 0) {
seglen = left > pcb->mss? pcb->mss: left;
/* allocate memory for tcp_seg, and fill in fields */
seg = memp_malloc(MEMP_TCP_SEG);
if(seg == NULL) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: could not allocate memory for tcp_seg\n"));
goto memerr;
}
seg->next = NULL;
seg->p = NULL;
if(queue == NULL) {
queue = seg;
} else {
for(useg = queue; useg->next != NULL; useg = useg->next);
useg->next = seg;
}
/* If copy is set, memory should be allocated
and data copied into pbuf, otherwise data comes from
ROM or other static memory, and need not be copied. If
optdata is != NULL, we have options instead of data. */
if(optdata != NULL) {
if((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
goto memerr;
}
++queuelen;
seg->dataptr = seg->p->payload;
} else if(copy) {
if((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: could not allocate memory for pbuf copy\n"));
goto memerr;
}
++queuelen;
if(arg != NULL) {
memcpy(seg->p->payload, ptr, seglen);
}
seg->dataptr = seg->p->payload;
} else {
/* Do not copy the data. */
if((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: could not allocate memory for pbuf non-copy\n"));
goto memerr;
}
++queuelen;
p->payload = ptr;
seg->dataptr = ptr;
if((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) {
pbuf_free(p);
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: could not allocate memory for header pbuf\n"));
goto memerr;
}
++queuelen;
pbuf_chain(seg->p, p);
}
if(queuelen > TCP_SND_QUEUELEN) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: queue too long %d (%d)\n", queuelen, TCP_SND_QUEUELEN));
goto memerr;
}
seg->len = seglen;
/* if((flags & TCP_SYN) || (flags & TCP_FIN)) {
++seg->len;
}*/
/* build TCP header */
if(pbuf_header(seg->p, TCP_HLEN)) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: no room for TCP header in pbuf.\n"));
#ifdef TCP_STATS
++stats.tcp.err;
#endif /* TCP_STATS */
goto memerr;
}
seg->tcphdr = seg->p->payload;
seg->tcphdr->src = htons(pcb->local_port);
seg->tcphdr->dest = htons(pcb->remote_port);
seg->tcphdr->seqno = htonl(seqno);
seg->tcphdr->urgp = 0;
TCPH_FLAGS_SET(seg->tcphdr, flags);
/* don't fill in tcphdr->ackno and tcphdr->wnd until later */
if(optdata == NULL) {
TCPH_OFFSET_SET(seg->tcphdr, 5 << 4);
} else {
TCPH_OFFSET_SET(seg->tcphdr, (5 + optlen / 4) << 4);
/* Copy options into data portion of segment.
Options can thus only be sent in non data carrying
segments such as SYN|ACK. */
memcpy(seg->dataptr, optdata, optlen);
}
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: queueing %lu:%lu (0x%x)\n",
ntohl(seg->tcphdr->seqno),
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
flags));
left -= seglen;
seqno += seglen;
ptr = (void *)((char *)ptr + seglen);
}
/* Go to the last segment on the ->unsent queue. */
if(pcb->unsent == NULL) {
useg = NULL;
} else {
for(useg = pcb->unsent; useg->next != NULL; useg = useg->next);
}
/* If there is room in the last pbuf on the unsent queue,
chain the first pbuf on the queue together with that. */
if(useg != NULL &&
TCP_TCPLEN(useg) != 0 &&
!(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) &&
!(flags & (TCP_SYN | TCP_FIN)) &&
useg->len + queue->len <= pcb->mss) {
/* Remove TCP header from first segment. */
pbuf_header(queue->p, -TCP_HLEN);
pbuf_chain(useg->p, queue->p);
useg->len += queue->len;
useg->next = queue->next;
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: chaining, new len %u\n", useg->len));
if(seg == queue) {
seg = NULL;
}
memp_free(MEMP_TCP_SEG, queue);
} else {
if(useg == NULL) {
pcb->unsent = queue;
} else {
useg->next = queue;
}
}
if((flags & TCP_SYN) || (flags & TCP_FIN)) {
++len;
}
pcb->snd_lbb += len;
pcb->snd_buf -= len;
pcb->snd_queuelen = queuelen;
DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %d (after enqueued)\n", pcb->snd_queuelen));
#ifdef LWIP_DEBUG
if(pcb->snd_queuelen != 0) {
ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
#endif /* LWIP_DEBUG */
/* Set the PSH flag in the last segment that we enqueued, but only
if the segment has data (indicated by seglen > 0). */
if(seg != NULL && seglen > 0 && seg->tcphdr != NULL) {
TCPH_FLAGS_SET(seg->tcphdr, TCPH_FLAGS(seg->tcphdr) | TCP_PSH);
}
return ERR_OK;
memerr:
#ifdef TCP_STATS
++stats.tcp.memerr;
#endif /* TCP_STATS */
if(queue != NULL) {
tcp_segs_free(queue);
}
#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 */
wnd = MIN(pcb->snd_wnd, pcb->cwnd);
seg = pcb->unsent;
if(((seg == NULL)
|| (ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd))
&& (pcb->flags & TF_ACK_NOW)) {
/* If no segments are enqueued but we should send an ACK, we
construct the ACK and send it. */
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
pcb->rcv_adv = pcb->rcv_nxt + pcb->rcv_wnd;
p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM);
if(p == NULL) {
DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue: (ACK) could not allocate pbuf\n"));
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);
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;
#if CHECKSUM_GEN_TCP
tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
IP_PROTO_TCP, p->tot_len);
#endif
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\n"));
}
#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);
pcb->rcv_adv = pcb->rcv_nxt + pcb->rcv_wnd;
}
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;
}
/**
* Called by tcp_process. Checks if the given segment is an ACK for outstanding
* data, and if so frees the memory of the buffered data. Next, is places the
* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
* i it has been removed from the buffer.
*
* If the incoming segment constitutes an ACK for a segment that was used for RTT
* estimation, the RTT is estimated here as well.
*
* Called from tcp_process().
*/
static void
tcp_receive(struct tcp_pcb *pcb)
{
struct tcp_seg *next;
#if TCP_QUEUE_OOSEQ
struct tcp_seg *prev, *cseg;
#endif
struct pbuf *p;
s32_t off;
s16_t m;
u32_t right_wnd_edge;
u16_t new_tot_len;
int found_dupack = 0;
if (flags & TCP_ACK) {
right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
/* Update window. */
if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
pcb->snd_wnd = tcphdr->wnd;
pcb->snd_wl1 = seqno;
pcb->snd_wl2 = ackno;
if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
pcb->persist_backoff = 0;
}
LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
#if TCP_WND_DEBUG
} else {
if (pcb->snd_wnd != tcphdr->wnd) {
LWIP_DEBUGF(TCP_WND_DEBUG,
("tcp_receive: no window update lastack %"U32_F" ackno %"
U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
}
#endif /* TCP_WND_DEBUG */
}
/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
* duplicate ack if:
* 1) It doesn't ACK new data
* 2) length of received packet is zero (i.e. no payload)
* 3) the advertised window hasn't changed
* 4) There is outstanding unacknowledged data (retransmission timer running)
* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
*
* If it passes all five, should process as a dupack:
* a) dupacks < 3: do nothing
* b) dupacks == 3: fast retransmit
* c) dupacks > 3: increase cwnd
*
* If it only passes 1-3, should reset dupack counter (and add to
* stats, which we don't do in lwIP)
*
* If it only passes 1, should reset dupack counter
*
*/
/* Clause 1 */
if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
pcb->acked = 0;
/* Clause 2 */
if (tcplen == 0) {
/* Clause 3 */
if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge) {
/* Clause 4 */
if (pcb->rtime >= 0) {
/* Clause 5 */
if (pcb->lastack == ackno) {
found_dupack = 1;
if (pcb->dupacks + 1 > pcb->dupacks)
++pcb->dupacks;
if (pcb->dupacks > 3) {
/* Inflate the congestion window, but not if it means that
the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
} else if (pcb->dupacks == 3) {
/* Do fast retransmit */
tcp_rexmit_fast(pcb);
}
}
}
}
}
/* If Clause (1) or more is true, but not a duplicate ack, reset
* count of consecutive duplicate acks */
if (!found_dupack) {
pcb->dupacks = 0;
}
} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
/* We come here when the ACK acknowledges new data. */
/* Reset the "IN Fast Retransmit" flag, since we are no longer
in fast retransmit. Also reset the congestion window to the
slow start threshold. */
if (pcb->flags & TF_INFR) {
pcb->flags &= ~TF_INFR;
pcb->cwnd = pcb->ssthresh;
}
/* Reset the number of retransmissions. */
pcb->nrtx = 0;
/* Reset the retransmission time-out. */
pcb->rto = (pcb->sa >> 3) + pcb->sv;
/* Update the send buffer space. Diff between the two can never exceed 64K? */
pcb->acked = (u16_t)(ackno - pcb->lastack);
pcb->snd_buf += pcb->acked;
/* Reset the fast retransmit variables. */
pcb->dupacks = 0;
pcb->lastack = ackno;
/* Update the congestion control variables (cwnd and
ssthresh). */
if (pcb->state >= ESTABLISHED) {
if (pcb->cwnd < pcb->ssthresh) {
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
} else {
u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
if (new_cwnd > pcb->cwnd) {
pcb->cwnd = new_cwnd;
}
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
}
}
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
ackno,
pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno): 0,
pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
/* Remove segment from the unacknowledged list if the incoming
ACK acknowlegdes them. */
while (pcb->unacked != NULL &&
TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked), ackno)) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
ntohl(pcb->unacked->tcphdr->seqno),
ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked)));
next = pcb->unacked;
pcb->unacked = pcb->unacked->next;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
/* Prevent ACK for FIN to generate a sent event */
if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
pcb->acked--;
}
pcb->snd_queuelen -= pbuf_clen(next->p);
tcp_seg_free(next);
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL);
}
}
/* If there's nothing left to acknowledge, stop the retransmit
timer, otherwise reset it to start again */
if(pcb->unacked == NULL)
pcb->rtime = -1;
else
pcb->rtime = 0;
pcb->polltmr = 0;
} else {
