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_IP, TCP_HLEN, PBUF_RAM);
if (p == NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
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_HDRLEN_SET(tcphdr, 5);
tcphdr->chksum = 0;
#if CHECKSUM_GEN_TCP
tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
IP_PROTO_TCP, p->tot_len);
#endif
TCP_STATS_INC(tcp.xmit);
snmp_inc_tcpoutrsts();
/* Send output with hardcoded TTL since we have no access to the pcb */
ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
pbuf_free(p);
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
}
/** Create a TCP segment usable for passing to tcp_input */
struct pbuf*
tcp_create_segment(ip_addr_t* src_ip, ip_addr_t* dst_ip,
u16_t src_port, u16_t dst_port, void* data, size_t data_len,
u32_t seqno, u32_t ackno, u8_t headerflags)
{
struct pbuf* p;
struct ip_hdr* iphdr;
struct tcp_hdr* tcphdr;
u16_t pbuf_len = (u16_t)(sizeof(struct ip_hdr) + sizeof(struct tcp_hdr) + data_len);
p = pbuf_alloc(PBUF_RAW, pbuf_len, PBUF_POOL);
EXPECT_RETNULL(p != NULL);
EXPECT_RETNULL(p->next == NULL);
memset(p->payload, 0, p->len);
iphdr = p->payload;
/* fill IP header */
iphdr->dest.addr = dst_ip->addr;
iphdr->src.addr = src_ip->addr;
IPH_VHLTOS_SET(iphdr, 4, IP_HLEN / 4, 0);
IPH_LEN_SET(iphdr, htons(p->tot_len));
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
pbuf_header(p, -(s16_t)sizeof(struct ip_hdr));
tcphdr = p->payload;
tcphdr->src = htons(src_port);
tcphdr->dest = htons(dst_port);
tcphdr->seqno = htonl(seqno);
tcphdr->ackno = htonl(ackno);
TCPH_HDRLEN_SET(tcphdr, sizeof(struct tcp_hdr)/4);
TCPH_FLAGS_SET(tcphdr, headerflags);
tcphdr->wnd = htons(TCP_WND);
/* copy data */
memcpy((char*)tcphdr + sizeof(struct tcp_hdr), data, data_len);
/* calculate checksum */
tcphdr->chksum = inet_chksum_pseudo(p, src_ip, dst_ip,
IP_PROTO_TCP, p->tot_len);
pbuf_header(p, sizeof(struct ip_hdr));
return p;
}
static struct tcp_hdr *
tcp_output_set_header(struct tcp_pcb *pcb, struct pbuf *p, int optlen,
u32_t seqno_be /* already in network byte order */)
{
struct tcp_hdr *tcphdr = p->payload;
tcphdr->src = htons(pcb->local_port);
tcphdr->dest = htons(pcb->remote_port);
tcphdr->seqno = seqno_be;
tcphdr->ackno = htonl(pcb->rcv_nxt);
TCPH_FLAGS_SET(tcphdr, TCP_ACK);
tcphdr->wnd = htons(pcb->rcv_ann_wnd);
tcphdr->urgp = 0;
TCPH_HDRLEN_SET(tcphdr, (5 + optlen / 4));
tcphdr->chksum = 0;
/* If we're sending a packet, update the announced right window edge */
pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
return tcphdr;
}
void
tcp_keepalive(struct tcp_pcb *pcb)
{
struct pbuf *p;
struct tcp_hdr *tcphdr;
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip),
ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip)));
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt %"U16_F"\n", tcp_ticks, pcb->tmr, pcb->keep_cnt));
p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
if(p == NULL) {
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: could not allocate memory for pbuf\n"));
return;
}
tcphdr = p->payload;
tcphdr->src = htons(pcb->local_port);
tcphdr->dest = htons(pcb->remote_port);
tcphdr->seqno = htonl(pcb->snd_nxt - 1);
tcphdr->ackno = htonl(pcb->rcv_nxt);
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
TCP_STATS_INC(tcp.xmit);
/* Send output to IP */
ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
pbuf_free(p);
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n", pcb->snd_nxt - 1, pcb->rcv_nxt));
}
/** Create a TCP segment usable for passing to tcp_input */
static struct pbuf*
tcp_create_segment_wnd(ip_addr_t* src_ip, ip_addr_t* dst_ip,
u16_t src_port, u16_t dst_port, void* data, size_t data_len,
u32_t seqno, u32_t ackno, u8_t headerflags, u16_t wnd)
{
struct pbuf *p, *q;
struct ip_hdr* iphdr;
struct tcp_hdr* tcphdr;
u16_t pbuf_len = (u16_t)(sizeof(struct ip_hdr) + sizeof(struct tcp_hdr) + data_len);
LWIP_ASSERT("data_len too big", data_len <= 0xFFFF);
p = pbuf_alloc(PBUF_RAW, pbuf_len, PBUF_POOL);
EXPECT_RETNULL(p != NULL);
/* first pbuf must be big enough to hold the headers */
EXPECT_RETNULL(p->len >= (sizeof(struct ip_hdr) + sizeof(struct tcp_hdr)));
if (data_len > 0) {
/* first pbuf must be big enough to hold at least 1 data byte, too */
EXPECT_RETNULL(p->len > (sizeof(struct ip_hdr) + sizeof(struct tcp_hdr)));
}
for(q = p; q != NULL; q = q->next) {
memset(q->payload, 0, q->len);
}
iphdr = (struct ip_hdr*)p->payload;
/* fill IP header */
iphdr->dest.addr = ip_2_ip4(dst_ip)->addr;
iphdr->src.addr = ip_2_ip4(src_ip)->addr;
IPH_VHL_SET(iphdr, 4, IP_HLEN / 4);
IPH_TOS_SET(iphdr, 0);
IPH_LEN_SET(iphdr, htons(p->tot_len));
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
/* let p point to TCP header */
pbuf_header(p, -(s16_t)sizeof(struct ip_hdr));
tcphdr = (struct tcp_hdr*)p->payload;
tcphdr->src = htons(src_port);
tcphdr->dest = htons(dst_port);
tcphdr->seqno = htonl(seqno);
tcphdr->ackno = htonl(ackno);
TCPH_HDRLEN_SET(tcphdr, sizeof(struct tcp_hdr)/4);
TCPH_FLAGS_SET(tcphdr, headerflags);
tcphdr->wnd = htons(wnd);
if (data_len > 0) {
/* let p point to TCP data */
pbuf_header(p, -(s16_t)sizeof(struct tcp_hdr));
/* copy data */
pbuf_take(p, data, (u16_t)data_len);
/* let p point to TCP header again */
pbuf_header(p, sizeof(struct tcp_hdr));
}
/* calculate checksum */
tcphdr->chksum = ip_chksum_pseudo(p,
IP_PROTO_TCP, p->tot_len, src_ip, dst_ip);
pbuf_header(p, sizeof(struct ip_hdr));
return p;
}
/* 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;
}
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;
}
