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lwip/core/tcp_out.c@11:da4498f591ee, 2010-08-05 (annotated)

Committer:: donatien
Date:: Thu Aug 05 15:01:33 2010 +0000
Revision:: 11:da4498f591ee
Parent:: 5:dd63a1e02b1b

Who changed what in which revision?

User	Revision	Line number	New contents of line
donatien	0:632c9925f013	1	/**
donatien	0:632c9925f013	2	* @file
donatien	0:632c9925f013	3	* Transmission Control Protocol, outgoing traffic
donatien	0:632c9925f013	4	*
donatien	0:632c9925f013	5	* The output functions of TCP.
donatien	0:632c9925f013	6	*
donatien	0:632c9925f013	7	*/
donatien	0:632c9925f013	8
donatien	0:632c9925f013	9	/*
donatien	0:632c9925f013	10	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
donatien	0:632c9925f013	11	* All rights reserved.
donatien	0:632c9925f013	12	*
donatien	0:632c9925f013	13	* Redistribution and use in source and binary forms, with or without modification,
donatien	0:632c9925f013	14	* are permitted provided that the following conditions are met:
donatien	0:632c9925f013	15	*
donatien	0:632c9925f013	16	* 1. Redistributions of source code must retain the above copyright notice,
donatien	0:632c9925f013	17	* this list of conditions and the following disclaimer.
donatien	0:632c9925f013	18	* 2. Redistributions in binary form must reproduce the above copyright notice,
donatien	0:632c9925f013	19	* this list of conditions and the following disclaimer in the documentation
donatien	0:632c9925f013	20	* and/or other materials provided with the distribution.
donatien	0:632c9925f013	21	* 3. The name of the author may not be used to endorse or promote products
donatien	0:632c9925f013	22	* derived from this software without specific prior written permission.
donatien	0:632c9925f013	23	*
donatien	0:632c9925f013	24	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
donatien	0:632c9925f013	25	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
donatien	0:632c9925f013	26	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
donatien	0:632c9925f013	27	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
donatien	0:632c9925f013	28	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
donatien	0:632c9925f013	29	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
donatien	0:632c9925f013	30	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
donatien	0:632c9925f013	31	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
donatien	0:632c9925f013	32	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
donatien	0:632c9925f013	33	* OF SUCH DAMAGE.
donatien	0:632c9925f013	34	*
donatien	0:632c9925f013	35	* This file is part of the lwIP TCP/IP stack.
donatien	0:632c9925f013	36	*
donatien	0:632c9925f013	37	* Author: Adam Dunkels <adam@sics.se>
donatien	0:632c9925f013	38	*
donatien	0:632c9925f013	39	*/
donatien	0:632c9925f013	40
donatien	0:632c9925f013	41	#include "lwip/opt.h"
donatien	0:632c9925f013	42
donatien	0:632c9925f013	43	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
donatien	0:632c9925f013	44
donatien	0:632c9925f013	45	#include "lwip/tcp_impl.h"
donatien	0:632c9925f013	46	#include "lwip/def.h"
donatien	0:632c9925f013	47	#include "lwip/mem.h"
donatien	0:632c9925f013	48	#include "lwip/memp.h"
donatien	0:632c9925f013	49	#include "lwip/sys.h"
donatien	0:632c9925f013	50	#include "lwip/ip_addr.h"
donatien	0:632c9925f013	51	#include "lwip/netif.h"
donatien	0:632c9925f013	52	#include "lwip/inet_chksum.h"
donatien	0:632c9925f013	53	#include "lwip/stats.h"
donatien	0:632c9925f013	54	#include "lwip/snmp.h"
donatien	0:632c9925f013	55
donatien	0:632c9925f013	56	#include <string.h>
donatien	0:632c9925f013	57
donatien	0:632c9925f013	58	/* Define some copy-macros for checksum-on-copy so that the code looks
donatien	0:632c9925f013	59	nicer by preventing too many ifdef's. */
donatien	0:632c9925f013	60	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	61	#define TCP_DATA_COPY(dst, src, len, seg) do { \
donatien	0:632c9925f013	62	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
donatien	0:632c9925f013	63	len, &seg->chksum, &seg->chksum_swapped); \
donatien	0:632c9925f013	64	seg->flags \|= TF_SEG_DATA_CHECKSUMMED; } while(0)
donatien	0:632c9925f013	65	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
donatien	0:632c9925f013	66	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
donatien	0:632c9925f013	67	#else /* TCP_CHECKSUM_ON_COPY*/
donatien	0:632c9925f013	68	#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
donatien	0:632c9925f013	69	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
donatien	0:632c9925f013	70	#endif /* TCP_CHECKSUM_ON_COPY*/
donatien	0:632c9925f013	71
donatien	0:632c9925f013	72	/** Define this to 1 for an extra check that the output checksum is valid
donatien	0:632c9925f013	73	* (usefule when the checksum is generated by the application, not the stack) */
donatien	0:632c9925f013	74	#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
donatien	0:632c9925f013	75	#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
donatien	0:632c9925f013	76	#endif
donatien	0:632c9925f013	77
donatien	0:632c9925f013	78	/* Forward declarations.*/
donatien	0:632c9925f013	79	static void tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb);
donatien	0:632c9925f013	80
donatien	0:632c9925f013	81	/** Allocate a pbuf and create a tcphdr at p->payload, used for output
donatien	0:632c9925f013	82	* functions other than the default tcp_output -> tcp_output_segment
donatien	0:632c9925f013	83	* (e.g. tcp_send_empty_ack, etc.)
donatien	0:632c9925f013	84	*
donatien	0:632c9925f013	85	* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
donatien	0:632c9925f013	86	* @param optlen length of header-options
donatien	0:632c9925f013	87	* @param datalen length of tcp data to reserve in pbuf
donatien	0:632c9925f013	88	* @param seqno_be seqno in network byte order (big-endian)
donatien	0:632c9925f013	89	* @return pbuf with p->payload being the tcp_hdr
donatien	0:632c9925f013	90	*/
donatien	0:632c9925f013	91	static struct pbuf *
donatien	0:632c9925f013	92	tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
donatien	0:632c9925f013	93	u32_t seqno_be /* already in network byte order */)
donatien	0:632c9925f013	94	{
donatien	0:632c9925f013	95	struct tcp_hdr *tcphdr;
donatien	0:632c9925f013	96	struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
donatien	0:632c9925f013	97	if (p != NULL) {
donatien	0:632c9925f013	98	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
donatien	0:632c9925f013	99	(p->len >= TCP_HLEN + optlen));
donatien	0:632c9925f013	100	tcphdr = (struct tcp_hdr *)p->payload;
donatien	0:632c9925f013	101	tcphdr->src = htons(pcb->local_port);
donatien	0:632c9925f013	102	tcphdr->dest = htons(pcb->remote_port);
donatien	0:632c9925f013	103	tcphdr->seqno = seqno_be;
donatien	0:632c9925f013	104	tcphdr->ackno = htonl(pcb->rcv_nxt);
donatien	0:632c9925f013	105	TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
donatien	0:632c9925f013	106	tcphdr->wnd = htons(pcb->rcv_ann_wnd);
donatien	0:632c9925f013	107	tcphdr->chksum = 0;
donatien	0:632c9925f013	108	tcphdr->urgp = 0;
donatien	0:632c9925f013	109
donatien	0:632c9925f013	110	/* If we're sending a packet, update the announced right window edge */
donatien	0:632c9925f013	111	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
donatien	0:632c9925f013	112	}
donatien	0:632c9925f013	113	return p;
donatien	0:632c9925f013	114	}
donatien	0:632c9925f013	115
donatien	0:632c9925f013	116	/**
donatien	0:632c9925f013	117	* Called by tcp_close() to send a segment including FIN flag but not data.
donatien	0:632c9925f013	118	*
donatien	0:632c9925f013	119	* @param pcb the tcp_pcb over which to send a segment
donatien	0:632c9925f013	120	* @return ERR_OK if sent, another err_t otherwise
donatien	0:632c9925f013	121	*/
donatien	0:632c9925f013	122	err_t
donatien	0:632c9925f013	123	tcp_send_fin(struct tcp_pcb *pcb)
donatien	0:632c9925f013	124	{
donatien	0:632c9925f013	125	/* first, try to add the fin to the last unsent segment */
donatien	0:632c9925f013	126	if (pcb->unsent != NULL) {
donatien	0:632c9925f013	127	struct tcp_seg *last_unsent;
donatien	0:632c9925f013	128	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
donatien	0:632c9925f013	129	last_unsent = last_unsent->next);
donatien	0:632c9925f013	130
donatien	0:632c9925f013	131	if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN \| TCP_FIN \| TCP_RST)) == 0) {
donatien	0:632c9925f013	132	/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
donatien	0:632c9925f013	133	TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
donatien	0:632c9925f013	134	return ERR_OK;
donatien	0:632c9925f013	135	}
donatien	0:632c9925f013	136	}
donatien	0:632c9925f013	137	/* no data, no length, flags, copy=1, no optdata */
donatien	0:632c9925f013	138	return tcp_enqueue_flags(pcb, TCP_FIN);
donatien	0:632c9925f013	139	}
donatien	0:632c9925f013	140
donatien	0:632c9925f013	141	/**
donatien	0:632c9925f013	142	* Create a TCP segment with prefilled header.
donatien	0:632c9925f013	143	*
donatien	0:632c9925f013	144	* Called by tcp_write and tcp_enqueue_flags.
donatien	0:632c9925f013	145	*
donatien	0:632c9925f013	146	* @param pcb Protocol control block for the TCP connection.
donatien	0:632c9925f013	147	* @param p pbuf that is used to hold the TCP header.
donatien	0:632c9925f013	148	* @param flags TCP flags for header.
donatien	0:632c9925f013	149	* @param seqno TCP sequence number of this packet
donatien	0:632c9925f013	150	* @param optflags options to include in TCP header
donatien	0:632c9925f013	151	* @return a new tcp_seg pointing to p, or NULL.
donatien	0:632c9925f013	152	* The TCP header is filled in except ackno and wnd.
donatien	0:632c9925f013	153	* p is freed on failure.
donatien	0:632c9925f013	154	*/
donatien	0:632c9925f013	155	static struct tcp_seg *
donatien	0:632c9925f013	156	tcp_create_segment(struct tcp_pcb pcb, struct pbuf p, u8_t flags, u32_t seqno, u8_t optflags)
donatien	0:632c9925f013	157	{
donatien	0:632c9925f013	158	struct tcp_seg *seg;
donatien	0:632c9925f013	159	u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
donatien	0:632c9925f013	160
donatien	0:632c9925f013	161	if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
donatien	0:632c9925f013	162	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no memory.\n"));
donatien	0:632c9925f013	163	pbuf_free(p);
donatien	0:632c9925f013	164	return NULL;
donatien	0:632c9925f013	165	}
donatien	0:632c9925f013	166	seg->flags = optflags;
donatien	0:632c9925f013	167	seg->next = NULL;
donatien	0:632c9925f013	168	seg->p = p;
donatien	0:632c9925f013	169	seg->dataptr = p->payload;
donatien	0:632c9925f013	170	seg->len = p->tot_len - optlen;
donatien	0:632c9925f013	171	#if TCP_OVERSIZE_DBGCHECK
donatien	0:632c9925f013	172	seg->oversize_left = 0;
donatien	0:632c9925f013	173	#endif /* TCP_OVERSIZE_DBGCHECK */
donatien	0:632c9925f013	174	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	175	seg->chksum = 0;
donatien	0:632c9925f013	176	seg->chksum_swapped = 0;
donatien	0:632c9925f013	177	/* check optflags */
donatien	0:632c9925f013	178	LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
donatien	0:632c9925f013	179	(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
donatien	0:632c9925f013	180	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	181
donatien	0:632c9925f013	182	/* build TCP header */
donatien	0:632c9925f013	183	if (pbuf_header(p, TCP_HLEN)) {
donatien	0:632c9925f013	184	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
donatien	0:632c9925f013	185	TCP_STATS_INC(tcp.err);
donatien	0:632c9925f013	186	tcp_seg_free(seg);
donatien	0:632c9925f013	187	return NULL;
donatien	0:632c9925f013	188	}
donatien	0:632c9925f013	189	seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
donatien	0:632c9925f013	190	seg->tcphdr->src = htons(pcb->local_port);
donatien	0:632c9925f013	191	seg->tcphdr->dest = htons(pcb->remote_port);
donatien	0:632c9925f013	192	seg->tcphdr->seqno = htonl(seqno);
donatien	0:632c9925f013	193	/* ackno is set in tcp_output */
donatien	0:632c9925f013	194	TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
donatien	0:632c9925f013	195	/* wnd and chksum are set in tcp_output */
donatien	0:632c9925f013	196	seg->tcphdr->urgp = 0;
donatien	0:632c9925f013	197	return seg;
donatien	0:632c9925f013	198	}
donatien	0:632c9925f013	199
donatien	0:632c9925f013	200	/**
donatien	0:632c9925f013	201	* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
donatien	0:632c9925f013	202	*
donatien	0:632c9925f013	203	* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
donatien	0:632c9925f013	204	* there may be extra bytes available at the end.
donatien	0:632c9925f013	205	*
donatien	0:632c9925f013	206	* @param layer flag to define header size.
donatien	0:632c9925f013	207	* @param length size of the pbuf's payload.
donatien	0:632c9925f013	208	* @param max_length maximum usable size of payload+oversize.
donatien	0:632c9925f013	209	* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
donatien	0:632c9925f013	210	* @param pcb The TCP connection that willo enqueue the pbuf.
donatien	0:632c9925f013	211	* @param apiflags API flags given to tcp_write.
donatien	0:632c9925f013	212	* @param first_seg true when this pbuf will be used in the first enqueued segment.
donatien	0:632c9925f013	213	* @param
donatien	0:632c9925f013	214	*/
donatien	0:632c9925f013	215	#if TCP_OVERSIZE
donatien	0:632c9925f013	216	static struct pbuf *
donatien	0:632c9925f013	217	tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
donatien	0:632c9925f013	218	u16_t oversize, struct tcp_pcb pcb, u8_t apiflags,
donatien	0:632c9925f013	219	u8_t first_seg)
donatien	0:632c9925f013	220	{
donatien	0:632c9925f013	221	struct pbuf *p;
donatien	0:632c9925f013	222	u16_t alloc = length;
donatien	0:632c9925f013	223
donatien	5:dd63a1e02b1b	224	#if LWIP_NETIF_TX_SINGLE_PBUF
donatien	5:dd63a1e02b1b	225	LWIP_UNUSED_ARG(max_length);
donatien	5:dd63a1e02b1b	226	LWIP_UNUSED_ARG(pcb);
donatien	5:dd63a1e02b1b	227	LWIP_UNUSED_ARG(apiflags);
donatien	5:dd63a1e02b1b	228	LWIP_UNUSED_ARG(first_seg);
donatien	5:dd63a1e02b1b	229	/* always create MSS-sized pbufs */
donatien	5:dd63a1e02b1b	230	alloc = TCP_MSS;
donatien	5:dd63a1e02b1b	231	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
donatien	0:632c9925f013	232	if (length < max_length) {
donatien	0:632c9925f013	233	/* Should we allocate an oversized pbuf, or just the minimum
donatien	0:632c9925f013	234	* length required? If tcp_write is going to be called again
donatien	0:632c9925f013	235	* before this segment is transmitted, we want the oversized
donatien	0:632c9925f013	236	* buffer. If the segment will be transmitted immediately, we can
donatien	0:632c9925f013	237	* save memory by allocating only length. We use a simple
donatien	0:632c9925f013	238	* heuristic based on the following information:
donatien	0:632c9925f013	239	*
donatien	0:632c9925f013	240	* Did the user set TCP_WRITE_FLAG_MORE?
donatien	0:632c9925f013	241	*
donatien	0:632c9925f013	242	* Will the Nagle algorithm defer transmission of this segment?
donatien	0:632c9925f013	243	*/
donatien	0:632c9925f013	244	if ((apiflags & TCP_WRITE_FLAG_MORE) \|\|
donatien	0:632c9925f013	245	(!(pcb->flags & TF_NODELAY) &&
donatien	0:632c9925f013	246	(!first_seg \|\|
donatien	0:632c9925f013	247	pcb->unsent != NULL \|\|
donatien	0:632c9925f013	248	pcb->unacked != NULL))) {
donatien	0:632c9925f013	249	alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
donatien	0:632c9925f013	250	}
donatien	0:632c9925f013	251	}
donatien	5:dd63a1e02b1b	252	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
donatien	0:632c9925f013	253	p = pbuf_alloc(layer, alloc, PBUF_RAM);
donatien	0:632c9925f013	254	if (p == NULL) {
donatien	0:632c9925f013	255	return NULL;
donatien	0:632c9925f013	256	}
donatien	0:632c9925f013	257	LWIP_ASSERT("need unchained pbuf", p->next == NULL);
donatien	0:632c9925f013	258	*oversize = p->len - length;
donatien	0:632c9925f013	259	/* trim p->len to the currently used size */
donatien	0:632c9925f013	260	p->len = p->tot_len = length;
donatien	0:632c9925f013	261	return p;
donatien	0:632c9925f013	262	}
donatien	0:632c9925f013	263	#else /* TCP_OVERSIZE */
donatien	0:632c9925f013	264	#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
donatien	0:632c9925f013	265	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	266
donatien	0:632c9925f013	267	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	268	/** Add a checksum of newly added data to the segment */
donatien	0:632c9925f013	269	static void
donatien	0:632c9925f013	270	tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
donatien	0:632c9925f013	271	u8_t *seg_chksum_swapped)
donatien	0:632c9925f013	272	{
donatien	0:632c9925f013	273	u32_t helper;
donatien	0:632c9925f013	274	/* add chksum to old chksum and fold to u16_t */
donatien	0:632c9925f013	275	helper = chksum + *seg_chksum;
donatien	0:632c9925f013	276	chksum = FOLD_U32T(helper);
donatien	0:632c9925f013	277	if ((len & 1) != 0) {
donatien	0:632c9925f013	278	seg_chksum_swapped = 1 - seg_chksum_swapped;
donatien	0:632c9925f013	279	chksum = SWAP_BYTES_IN_WORD(chksum);
donatien	0:632c9925f013	280	}
donatien	0:632c9925f013	281	*seg_chksum = chksum;
donatien	0:632c9925f013	282	}
donatien	0:632c9925f013	283	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	284
donatien	5:dd63a1e02b1b	285	/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
donatien	5:dd63a1e02b1b	286	*
donatien	5:dd63a1e02b1b	287	* @param pcb the tcp pcb to check for
donatien	5:dd63a1e02b1b	288	* @param len length of data to send (checked agains snd_buf)
donatien	5:dd63a1e02b1b	289	* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
donatien	5:dd63a1e02b1b	290	*/
donatien	5:dd63a1e02b1b	291	static err_t
donatien	5:dd63a1e02b1b	292	tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
donatien	5:dd63a1e02b1b	293	{
donatien	5:dd63a1e02b1b	294	/* connection is in invalid state for data transmission? */
donatien	5:dd63a1e02b1b	295	if ((pcb->state != ESTABLISHED) &&
donatien	5:dd63a1e02b1b	296	(pcb->state != CLOSE_WAIT) &&
donatien	5:dd63a1e02b1b	297	(pcb->state != SYN_SENT) &&
donatien	5:dd63a1e02b1b	298	(pcb->state != SYN_RCVD)) {
donatien	5:dd63a1e02b1b	299	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_STATE \| LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
donatien	5:dd63a1e02b1b	300	return ERR_CONN;
donatien	5:dd63a1e02b1b	301	} else if (len == 0) {
donatien	5:dd63a1e02b1b	302	return ERR_OK;
donatien	5:dd63a1e02b1b	303	}
donatien	5:dd63a1e02b1b	304
donatien	5:dd63a1e02b1b	305	/* fail on too much data */
donatien	5:dd63a1e02b1b	306	if (len > pcb->snd_buf) {
donatien	5:dd63a1e02b1b	307	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
donatien	5:dd63a1e02b1b	308	len, pcb->snd_buf));
donatien	5:dd63a1e02b1b	309	pcb->flags \|= TF_NAGLEMEMERR;
donatien	5:dd63a1e02b1b	310	return ERR_MEM;
donatien	5:dd63a1e02b1b	311	}
donatien	5:dd63a1e02b1b	312
donatien	5:dd63a1e02b1b	313	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
donatien	5:dd63a1e02b1b	314
donatien	5:dd63a1e02b1b	315	/* If total number of pbufs on the unsent/unacked queues exceeds the
donatien	5:dd63a1e02b1b	316	* configured maximum, return an error */
donatien	5:dd63a1e02b1b	317	/* check for configured max queuelen and possible overflow */
donatien	5:dd63a1e02b1b	318	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
donatien	5:dd63a1e02b1b	319	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
donatien	5:dd63a1e02b1b	320	pcb->snd_queuelen, TCP_SND_QUEUELEN));
donatien	5:dd63a1e02b1b	321	TCP_STATS_INC(tcp.memerr);
donatien	5:dd63a1e02b1b	322	pcb->flags \|= TF_NAGLEMEMERR;
donatien	5:dd63a1e02b1b	323	return ERR_MEM;
donatien	5:dd63a1e02b1b	324	}
donatien	5:dd63a1e02b1b	325	if (pcb->snd_queuelen != 0) {
donatien	5:dd63a1e02b1b	326	LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
donatien	5:dd63a1e02b1b	327	pcb->unacked != NULL \|\| pcb->unsent != NULL);
donatien	5:dd63a1e02b1b	328	} else {
donatien	5:dd63a1e02b1b	329	LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
donatien	5:dd63a1e02b1b	330	pcb->unacked == NULL && pcb->unsent == NULL);
donatien	5:dd63a1e02b1b	331	}
donatien	5:dd63a1e02b1b	332	return ERR_OK;
donatien	5:dd63a1e02b1b	333	}
donatien	5:dd63a1e02b1b	334
donatien	0:632c9925f013	335	/**
donatien	0:632c9925f013	336	* Write data for sending (but does not send it immediately).
donatien	0:632c9925f013	337	*
donatien	0:632c9925f013	338	* It waits in the expectation of more data being sent soon (as
donatien	0:632c9925f013	339	* it can send them more efficiently by combining them together).
donatien	0:632c9925f013	340	* To prompt the system to send data now, call tcp_output() after
donatien	0:632c9925f013	341	* calling tcp_write().
donatien	0:632c9925f013	342	*
donatien	0:632c9925f013	343	* @param pcb Protocol control block for the TCP connection to enqueue data for.
donatien	0:632c9925f013	344	* @param arg Pointer to the data to be enqueued for sending.
donatien	0:632c9925f013	345	* @param len Data length in bytes
donatien	0:632c9925f013	346	* @param apiflags combination of following flags :
donatien	0:632c9925f013	347	* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
donatien	0:632c9925f013	348	* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
donatien	0:632c9925f013	349	* @return ERR_OK if enqueued, another err_t on error
donatien	0:632c9925f013	350	*/
donatien	0:632c9925f013	351	err_t
donatien	0:632c9925f013	352	tcp_write(struct tcp_pcb pcb, const void arg, u16_t len, u8_t apiflags)
donatien	0:632c9925f013	353	{
donatien	0:632c9925f013	354	struct pbuf *concat_p = NULL;
donatien	0:632c9925f013	355	struct tcp_seg last_unsent = NULL, seg = NULL, prev_seg = NULL, queue = NULL;
donatien	0:632c9925f013	356	u16_t pos = 0; /* position in 'arg' data */
donatien	0:632c9925f013	357	u16_t queuelen;
donatien	0:632c9925f013	358	u8_t optlen = 0;
donatien	0:632c9925f013	359	u8_t optflags = 0;
donatien	0:632c9925f013	360	#if TCP_OVERSIZE
donatien	0:632c9925f013	361	u16_t oversize = 0;
donatien	0:632c9925f013	362	u16_t oversize_used = 0;
donatien	0:632c9925f013	363	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	364	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	365	u16_t concat_chksum = 0;
donatien	0:632c9925f013	366	u8_t concat_chksum_swapped = 0;
donatien	0:632c9925f013	367	u16_t concat_chksummed = 0;
donatien	0:632c9925f013	368	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	5:dd63a1e02b1b	369	err_t err;
donatien	0:632c9925f013	370
donatien	0:632c9925f013	371	#if LWIP_NETIF_TX_SINGLE_PBUF
donatien	0:632c9925f013	372	/* Always copy to try to create single pbufs for TX */
donatien	0:632c9925f013	373	apiflags \|= TCP_WRITE_FLAG_COPY;
donatien	0:632c9925f013	374	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
donatien	0:632c9925f013	375
donatien	0:632c9925f013	376	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
donatien	0:632c9925f013	377	(void *)pcb, arg, len, (u16_t)apiflags));
donatien	0:632c9925f013	378	LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
donatien	0:632c9925f013	379	arg != NULL, return ERR_ARG;);
donatien	0:632c9925f013	380
donatien	5:dd63a1e02b1b	381	err = tcp_write_checks(pcb, len);
donatien	5:dd63a1e02b1b	382	if (err != ERR_OK) {
donatien	5:dd63a1e02b1b	383	return err;
donatien	0:632c9925f013	384	}
donatien	0:632c9925f013	385	queuelen = pcb->snd_queuelen;
donatien	0:632c9925f013	386
donatien	0:632c9925f013	387	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	388	if ((pcb->flags & TF_TIMESTAMP)) {
donatien	0:632c9925f013	389	optflags = TF_SEG_OPTS_TS;
donatien	0:632c9925f013	390	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
donatien	0:632c9925f013	391	}
donatien	0:632c9925f013	392	#endif /* LWIP_TCP_TIMESTAMPS */
donatien	0:632c9925f013	393
donatien	0:632c9925f013	394
donatien	0:632c9925f013	395	/*
donatien	0:632c9925f013	396	* TCP segmentation is done in three phases with increasing complexity:
donatien	0:632c9925f013	397	*
donatien	0:632c9925f013	398	* 1. Copy data directly into an oversized pbuf.
donatien	0:632c9925f013	399	* 2. Chain a new pbuf to the end of pcb->unsent.
donatien	0:632c9925f013	400	* 3. Create new segments.
donatien	0:632c9925f013	401	*
donatien	0:632c9925f013	402	* We may run out of memory at any point. In that case we must
donatien	0:632c9925f013	403	* return ERR_MEM and not change anything in pcb. Therefore, all
donatien	0:632c9925f013	404	* changes are recorded in local variables and committed at the end
donatien	0:632c9925f013	405	* of the function. Some pcb fields are maintained in local copies:
donatien	0:632c9925f013	406	*
donatien	0:632c9925f013	407	* queuelen = pcb->snd_queuelen
donatien	0:632c9925f013	408	* oversize = pcb->unsent_oversize
donatien	0:632c9925f013	409	*
donatien	0:632c9925f013	410	* These variables are set consistently by the phases:
donatien	0:632c9925f013	411	*
donatien	0:632c9925f013	412	* seg points to the last segment tampered with.
donatien	0:632c9925f013	413	*
donatien	0:632c9925f013	414	* pos records progress as data is segmented.
donatien	0:632c9925f013	415	*/
donatien	0:632c9925f013	416
donatien	0:632c9925f013	417	/* Find the tail of the unsent queue. */
donatien	0:632c9925f013	418	if (pcb->unsent != NULL) {
donatien	0:632c9925f013	419	u16_t space;
donatien	0:632c9925f013	420	u16_t unsent_optlen;
donatien	0:632c9925f013	421
donatien	0:632c9925f013	422	/* @todo: this could be sped up by keeping last_unsent in the pcb */
donatien	0:632c9925f013	423	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
donatien	0:632c9925f013	424	last_unsent = last_unsent->next);
donatien	0:632c9925f013	425
donatien	0:632c9925f013	426	/* Usable space at the end of the last unsent segment */
donatien	0:632c9925f013	427	unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
donatien	0:632c9925f013	428	space = pcb->mss - (last_unsent->len + unsent_optlen);
donatien	0:632c9925f013	429
donatien	0:632c9925f013	430	/*
donatien	0:632c9925f013	431	* Phase 1: Copy data directly into an oversized pbuf.
donatien	0:632c9925f013	432	*
donatien	0:632c9925f013	433	* The number of bytes copied is recorded in the oversize_used
donatien	0:632c9925f013	434	* variable. The actual copying is done at the bottom of the
donatien	0:632c9925f013	435	* function.
donatien	0:632c9925f013	436	*/
donatien	0:632c9925f013	437	#if TCP_OVERSIZE
donatien	0:632c9925f013	438	#if TCP_OVERSIZE_DBGCHECK
donatien	0:632c9925f013	439	/* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
donatien	0:632c9925f013	440	LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
donatien	0:632c9925f013	441	pcb->unsent_oversize == last_unsent->oversize_left);
donatien	0:632c9925f013	442	#endif /* TCP_OVERSIZE_DBGCHECK */
donatien	0:632c9925f013	443	oversize = pcb->unsent_oversize;
donatien	0:632c9925f013	444	if (oversize > 0) {
donatien	0:632c9925f013	445	LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
donatien	0:632c9925f013	446	seg = last_unsent;
donatien	0:632c9925f013	447	oversize_used = oversize < len ? oversize : len;
donatien	0:632c9925f013	448	pos += oversize_used;
donatien	0:632c9925f013	449	oversize -= oversize_used;
donatien	0:632c9925f013	450	space -= oversize_used;
donatien	0:632c9925f013	451	}
donatien	0:632c9925f013	452	/* now we are either finished or oversize is zero */
donatien	0:632c9925f013	453	LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) \|\| (pos == len));
donatien	0:632c9925f013	454	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	455
donatien	0:632c9925f013	456	/*
donatien	0:632c9925f013	457	* Phase 2: Chain a new pbuf to the end of pcb->unsent.
donatien	0:632c9925f013	458	*
donatien	0:632c9925f013	459	* We don't extend segments containing SYN/FIN flags or options
donatien	0:632c9925f013	460	* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
donatien	0:632c9925f013	461	* the end.
donatien	0:632c9925f013	462	*/
donatien	0:632c9925f013	463	if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
donatien	0:632c9925f013	464	u16_t seglen = space < len - pos ? space : len - pos;
donatien	0:632c9925f013	465	seg = last_unsent;
donatien	0:632c9925f013	466
donatien	0:632c9925f013	467	/* Create a pbuf with a copy or reference to seglen bytes. We
donatien	0:632c9925f013	468	* can use PBUF_RAW here since the data appears in the middle of
donatien	0:632c9925f013	469	* a segment. A header will never be prepended. */
donatien	0:632c9925f013	470	if (apiflags & TCP_WRITE_FLAG_COPY) {
donatien	0:632c9925f013	471	/* Data is copied */
donatien	0:632c9925f013	472	if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
donatien	0:632c9925f013	473	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
donatien	0:632c9925f013	474	("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
donatien	0:632c9925f013	475	seglen));
donatien	0:632c9925f013	476	goto memerr;
donatien	0:632c9925f013	477	}
donatien	0:632c9925f013	478	#if TCP_OVERSIZE_DBGCHECK
donatien	0:632c9925f013	479	last_unsent->oversize_left = oversize;
donatien	0:632c9925f013	480	#endif /* TCP_OVERSIZE_DBGCHECK */
donatien	0:632c9925f013	481	TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
donatien	0:632c9925f013	482	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	483	concat_chksummed += seglen;
donatien	0:632c9925f013	484	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	485	} else {
donatien	0:632c9925f013	486	/* Data is not copied */
donatien	0:632c9925f013	487	if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
donatien	0:632c9925f013	488	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
donatien	0:632c9925f013	489	("tcp_write: could not allocate memory for zero-copy pbuf\n"));
donatien	0:632c9925f013	490	goto memerr;
donatien	0:632c9925f013	491	}
donatien	0:632c9925f013	492	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	493	/* calculate the checksum of nocopy-data */
donatien	0:632c9925f013	494	tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
donatien	0:632c9925f013	495	&concat_chksum, &concat_chksum_swapped);
donatien	0:632c9925f013	496	concat_chksummed += seglen;
donatien	0:632c9925f013	497	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	498	/* reference the non-volatile payload data */
donatien	0:632c9925f013	499	concat_p->payload = (u8_t*)arg + pos;
donatien	0:632c9925f013	500	}
donatien	0:632c9925f013	501
donatien	0:632c9925f013	502	pos += seglen;
donatien	0:632c9925f013	503	queuelen += pbuf_clen(concat_p);
donatien	0:632c9925f013	504	}
donatien	0:632c9925f013	505	} else {
donatien	0:632c9925f013	506	#if TCP_OVERSIZE
donatien	0:632c9925f013	507	LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
donatien	0:632c9925f013	508	pcb->unsent_oversize == 0);
donatien	0:632c9925f013	509	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	510	}
donatien	0:632c9925f013	511
donatien	0:632c9925f013	512	/*
donatien	0:632c9925f013	513	* Phase 3: Create new segments.
donatien	0:632c9925f013	514	*
donatien	0:632c9925f013	515	* The new segments are chained together in the local 'queue'
donatien	0:632c9925f013	516	* variable, ready to be appended to pcb->unsent.
donatien	0:632c9925f013	517	*/
donatien	0:632c9925f013	518	while (pos < len) {
donatien	0:632c9925f013	519	struct pbuf *p;
donatien	0:632c9925f013	520	u16_t left = len - pos;
donatien	0:632c9925f013	521	u16_t max_len = pcb->mss - optlen;
donatien	0:632c9925f013	522	u16_t seglen = left > max_len ? max_len : left;
donatien	0:632c9925f013	523	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	524	u16_t chksum = 0;
donatien	0:632c9925f013	525	u8_t chksum_swapped = 0;
donatien	0:632c9925f013	526	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	527
donatien	0:632c9925f013	528	if (apiflags & TCP_WRITE_FLAG_COPY) {
donatien	0:632c9925f013	529	/* If copy is set, memory should be allocated and data copied
donatien	0:632c9925f013	530	* into pbuf */
donatien	0:632c9925f013	531	if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
donatien	0:632c9925f013	532	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
donatien	0:632c9925f013	533	goto memerr;
donatien	0:632c9925f013	534	}
donatien	0:632c9925f013	535	LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
donatien	0:632c9925f013	536	(p->len >= seglen));
donatien	0:632c9925f013	537	TCP_DATA_COPY2((char )p->payload + optlen, (u8_t)arg + pos, seglen, &chksum, &chksum_swapped);
donatien	0:632c9925f013	538	} else {
donatien	0:632c9925f013	539	/* Copy is not set: First allocate a pbuf for holding the data.
donatien	0:632c9925f013	540	* Since the referenced data is available at least until it is
donatien	0:632c9925f013	541	* sent out on the link (as it has to be ACKed by the remote
donatien	0:632c9925f013	542	* party) we can safely use PBUF_ROM instead of PBUF_REF here.
donatien	0:632c9925f013	543	*/
donatien	0:632c9925f013	544	struct pbuf *p2;
donatien	0:632c9925f013	545	#if TCP_OVERSIZE
donatien	0:632c9925f013	546	LWIP_ASSERT("oversize == 0", oversize == 0);
donatien	0:632c9925f013	547	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	548	if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
donatien	0:632c9925f013	549	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
donatien	0:632c9925f013	550	goto memerr;
donatien	0:632c9925f013	551	}
donatien	0:632c9925f013	552	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	553	/* calculate the checksum of nocopy-data */
donatien	0:632c9925f013	554	chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
donatien	0:632c9925f013	555	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	556	/* reference the non-volatile payload data */
donatien	0:632c9925f013	557	p2->payload = (u8_t*)arg + pos;
donatien	0:632c9925f013	558
donatien	0:632c9925f013	559	/* Second, allocate a pbuf for the headers. */
donatien	0:632c9925f013	560	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
donatien	0:632c9925f013	561	/* If allocation fails, we have to deallocate the data pbuf as
donatien	0:632c9925f013	562	* well. */
donatien	0:632c9925f013	563	pbuf_free(p2);
donatien	0:632c9925f013	564	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for header pbuf\n"));
donatien	0:632c9925f013	565	goto memerr;
donatien	0:632c9925f013	566	}
donatien	0:632c9925f013	567	/* Concatenate the headers and data pbufs together. */
donatien	0:632c9925f013	568	pbuf_cat(p/header/, p2/data/);
donatien	0:632c9925f013	569	}
donatien	0:632c9925f013	570
donatien	0:632c9925f013	571	queuelen += pbuf_clen(p);
donatien	0:632c9925f013	572
donatien	0:632c9925f013	573	/* Now that there are more segments queued, we check again if the
donatien	0:632c9925f013	574	* length of the queue exceeds the configured maximum or
donatien	0:632c9925f013	575	* overflows. */
donatien	0:632c9925f013	576	if ((queuelen > TCP_SND_QUEUELEN) \|\| (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
donatien	0:632c9925f013	577	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
donatien	0:632c9925f013	578	pbuf_free(p);
donatien	0:632c9925f013	579	goto memerr;
donatien	0:632c9925f013	580	}
donatien	0:632c9925f013	581
donatien	0:632c9925f013	582	if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
donatien	0:632c9925f013	583	goto memerr;
donatien	0:632c9925f013	584	}
donatien	0:632c9925f013	585	#if TCP_OVERSIZE_DBGCHECK
donatien	0:632c9925f013	586	seg->oversize_left = oversize;
donatien	0:632c9925f013	587	#endif /* TCP_OVERSIZE_DBGCHECK */
donatien	0:632c9925f013	588	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	589	seg->chksum = chksum;
donatien	0:632c9925f013	590	seg->chksum_swapped = chksum_swapped;
donatien	0:632c9925f013	591	seg->flags \|= TF_SEG_DATA_CHECKSUMMED;
donatien	0:632c9925f013	592	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	593	/* Fix dataptr for the nocopy case */
donatien	0:632c9925f013	594	if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
donatien	0:632c9925f013	595	seg->dataptr = (u8_t*)arg + pos;
donatien	0:632c9925f013	596	}
donatien	0:632c9925f013	597
donatien	0:632c9925f013	598	/* first segment of to-be-queued data? */
donatien	0:632c9925f013	599	if (queue == NULL) {
donatien	0:632c9925f013	600	queue = seg;
donatien	0:632c9925f013	601	} else {
donatien	0:632c9925f013	602	/* Attach the segment to the end of the queued segments */
donatien	0:632c9925f013	603	LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
donatien	0:632c9925f013	604	prev_seg->next = seg;
donatien	0:632c9925f013	605	}
donatien	0:632c9925f013	606	/* remember last segment of to-be-queued data for next iteration */
donatien	0:632c9925f013	607	prev_seg = seg;
donatien	0:632c9925f013	608
donatien	0:632c9925f013	609	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
donatien	0:632c9925f013	610	ntohl(seg->tcphdr->seqno),
donatien	0:632c9925f013	611	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
donatien	0:632c9925f013	612
donatien	0:632c9925f013	613	pos += seglen;
donatien	0:632c9925f013	614	}
donatien	0:632c9925f013	615
donatien	0:632c9925f013	616	/*
donatien	0:632c9925f013	617	* All three segmentation phases were successful. We can commit the
donatien	0:632c9925f013	618	* transaction.
donatien	0:632c9925f013	619	*/
donatien	0:632c9925f013	620
donatien	0:632c9925f013	621	/*
donatien	0:632c9925f013	622	* Phase 1: If data has been added to the preallocated tail of
donatien	0:632c9925f013	623	* last_unsent, we update the length fields of the pbuf chain.
donatien	0:632c9925f013	624	*/
donatien	0:632c9925f013	625	#if TCP_OVERSIZE
donatien	0:632c9925f013	626	if (oversize_used > 0) {
donatien	0:632c9925f013	627	struct pbuf *p;
donatien	0:632c9925f013	628	/* Bump tot_len of whole chain, len of tail */
donatien	0:632c9925f013	629	for (p = last_unsent->p; p; p = p->next) {
donatien	0:632c9925f013	630	p->tot_len += oversize_used;
donatien	0:632c9925f013	631	if (p->next == NULL) {
donatien	0:632c9925f013	632	TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
donatien	0:632c9925f013	633	p->len += oversize_used;
donatien	0:632c9925f013	634	}
donatien	0:632c9925f013	635	}
donatien	0:632c9925f013	636	last_unsent->len += oversize_used;
donatien	0:632c9925f013	637	#if TCP_OVERSIZE_DBGCHECK
donatien	0:632c9925f013	638	last_unsent->oversize_left -= oversize_used;
donatien	0:632c9925f013	639	#endif /* TCP_OVERSIZE_DBGCHECK */
donatien	0:632c9925f013	640	}
donatien	0:632c9925f013	641	pcb->unsent_oversize = oversize;
donatien	0:632c9925f013	642	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	643
donatien	0:632c9925f013	644	/*
donatien	0:632c9925f013	645	* Phase 2: concat_p can be concatenated onto last_unsent->p
donatien	0:632c9925f013	646	*/
donatien	0:632c9925f013	647	if (concat_p != NULL) {
donatien	0:632c9925f013	648	LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
donatien	0:632c9925f013	649	(last_unsent != NULL));
donatien	0:632c9925f013	650	pbuf_cat(last_unsent->p, concat_p);
donatien	0:632c9925f013	651	last_unsent->len += concat_p->tot_len;
donatien	0:632c9925f013	652	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	653	if (concat_chksummed) {
donatien	0:632c9925f013	654	tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
donatien	0:632c9925f013	655	&last_unsent->chksum_swapped);
donatien	0:632c9925f013	656	last_unsent->flags \|= TF_SEG_DATA_CHECKSUMMED;
donatien	0:632c9925f013	657	}
donatien	0:632c9925f013	658	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	659	}
donatien	0:632c9925f013	660
donatien	0:632c9925f013	661	/*
donatien	0:632c9925f013	662	* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
donatien	0:632c9925f013	663	* is harmless
donatien	0:632c9925f013	664	*/
donatien	0:632c9925f013	665	if (last_unsent == NULL) {
donatien	0:632c9925f013	666	pcb->unsent = queue;
donatien	0:632c9925f013	667	} else {
donatien	0:632c9925f013	668	last_unsent->next = queue;
donatien	0:632c9925f013	669	}
donatien	0:632c9925f013	670
donatien	0:632c9925f013	671	/*
donatien	0:632c9925f013	672	* Finally update the pcb state.
donatien	0:632c9925f013	673	*/
donatien	0:632c9925f013	674	pcb->snd_lbb += len;
donatien	0:632c9925f013	675	pcb->snd_buf -= len;
donatien	0:632c9925f013	676	pcb->snd_queuelen = queuelen;
donatien	0:632c9925f013	677
donatien	0:632c9925f013	678	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
donatien	0:632c9925f013	679	pcb->snd_queuelen));
donatien	0:632c9925f013	680	if (pcb->snd_queuelen != 0) {
donatien	0:632c9925f013	681	LWIP_ASSERT("tcp_write: valid queue length",
donatien	0:632c9925f013	682	pcb->unacked != NULL \|\| pcb->unsent != NULL);
donatien	0:632c9925f013	683	}
donatien	0:632c9925f013	684
donatien	0:632c9925f013	685	/* Set the PSH flag in the last segment that we enqueued. */
donatien	0:632c9925f013	686	if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
donatien	0:632c9925f013	687	TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
donatien	0:632c9925f013	688	}
donatien	0:632c9925f013	689
donatien	0:632c9925f013	690	return ERR_OK;
donatien	0:632c9925f013	691	memerr:
donatien	0:632c9925f013	692	pcb->flags \|= TF_NAGLEMEMERR;
donatien	0:632c9925f013	693	TCP_STATS_INC(tcp.memerr);
donatien	0:632c9925f013	694
donatien	0:632c9925f013	695	if (concat_p != NULL) {
donatien	0:632c9925f013	696	pbuf_free(concat_p);
donatien	0:632c9925f013	697	}
donatien	0:632c9925f013	698	if (queue != NULL) {
donatien	0:632c9925f013	699	tcp_segs_free(queue);
donatien	0:632c9925f013	700	}
donatien	0:632c9925f013	701	if (pcb->snd_queuelen != 0) {
donatien	0:632c9925f013	702	LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL \|\|
donatien	0:632c9925f013	703	pcb->unsent != NULL);
donatien	0:632c9925f013	704	}
donatien	0:632c9925f013	705	LWIP_DEBUGF(TCP_QLEN_DEBUG \| LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
donatien	0:632c9925f013	706	return ERR_MEM;
donatien	0:632c9925f013	707	}
donatien	0:632c9925f013	708
donatien	0:632c9925f013	709	/**
donatien	0:632c9925f013	710	* Enqueue TCP options for transmission.
donatien	0:632c9925f013	711	*
donatien	0:632c9925f013	712	* Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
donatien	0:632c9925f013	713	*
donatien	0:632c9925f013	714	* @param pcb Protocol control block for the TCP connection.
donatien	0:632c9925f013	715	* @param flags TCP header flags to set in the outgoing segment.
donatien	0:632c9925f013	716	* @param optdata pointer to TCP options, or NULL.
donatien	0:632c9925f013	717	* @param optlen length of TCP options in bytes.
donatien	0:632c9925f013	718	*/
donatien	0:632c9925f013	719	err_t
donatien	0:632c9925f013	720	tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
donatien	0:632c9925f013	721	{
donatien	0:632c9925f013	722	struct pbuf *p;
donatien	0:632c9925f013	723	struct tcp_seg *seg;
donatien	0:632c9925f013	724	u8_t optflags = 0;
donatien	0:632c9925f013	725	u8_t optlen = 0;
donatien	0:632c9925f013	726
donatien	0:632c9925f013	727	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
donatien	0:632c9925f013	728
donatien	0:632c9925f013	729	LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
donatien	0:632c9925f013	730	(flags & (TCP_SYN \| TCP_FIN)) != 0);
donatien	0:632c9925f013	731
donatien	0:632c9925f013	732	/* check for configured max queuelen and possible overflow */
donatien	0:632c9925f013	733	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
donatien	0:632c9925f013	734	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
donatien	0:632c9925f013	735	pcb->snd_queuelen, TCP_SND_QUEUELEN));
donatien	0:632c9925f013	736	TCP_STATS_INC(tcp.memerr);
donatien	0:632c9925f013	737	pcb->flags \|= TF_NAGLEMEMERR;
donatien	0:632c9925f013	738	return ERR_MEM;
donatien	0:632c9925f013	739	}
donatien	0:632c9925f013	740
donatien	0:632c9925f013	741	if (flags & TCP_SYN) {
donatien	0:632c9925f013	742	optflags = TF_SEG_OPTS_MSS;
donatien	0:632c9925f013	743	}
donatien	0:632c9925f013	744	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	745	if ((pcb->flags & TF_TIMESTAMP)) {
donatien	0:632c9925f013	746	optflags \|= TF_SEG_OPTS_TS;
donatien	0:632c9925f013	747	}
donatien	0:632c9925f013	748	#endif /* LWIP_TCP_TIMESTAMPS */
donatien	0:632c9925f013	749	optlen = LWIP_TCP_OPT_LENGTH(optflags);
donatien	0:632c9925f013	750
donatien	0:632c9925f013	751	/* tcp_enqueue_flags is always called with either SYN or FIN in flags.
donatien	0:632c9925f013	752	* We need one available snd_buf byte to do that.
donatien	0:632c9925f013	753	* This means we can't send FIN while snd_buf==0. A better fix would be to
donatien	0:632c9925f013	754	* not include SYN and FIN sequence numbers in the snd_buf count. */
donatien	0:632c9925f013	755	if (pcb->snd_buf == 0) {
donatien	0:632c9925f013	756	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: no send buffer available\n"));
donatien	0:632c9925f013	757	TCP_STATS_INC(tcp.memerr);
donatien	0:632c9925f013	758	return ERR_MEM;
donatien	0:632c9925f013	759	}
donatien	0:632c9925f013	760
donatien	0:632c9925f013	761	/* Allocate pbuf with room for TCP header + options */
donatien	0:632c9925f013	762	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
donatien	0:632c9925f013	763	pcb->flags \|= TF_NAGLEMEMERR;
donatien	0:632c9925f013	764	TCP_STATS_INC(tcp.memerr);
donatien	0:632c9925f013	765	return ERR_MEM;
donatien	0:632c9925f013	766	}
donatien	0:632c9925f013	767	LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
donatien	0:632c9925f013	768	(p->len >= optlen));
donatien	0:632c9925f013	769
donatien	0:632c9925f013	770	/* Allocate memory for tcp_seg, and fill in fields. */
donatien	0:632c9925f013	771	if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
donatien	0:632c9925f013	772	pcb->flags \|= TF_NAGLEMEMERR;
donatien	0:632c9925f013	773	TCP_STATS_INC(tcp.memerr);
donatien	0:632c9925f013	774	return ERR_MEM;
donatien	0:632c9925f013	775	}
donatien	0:632c9925f013	776	LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
donatien	0:632c9925f013	777
donatien	0:632c9925f013	778	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE,
donatien	0:632c9925f013	779	("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
donatien	0:632c9925f013	780	ntohl(seg->tcphdr->seqno),
donatien	0:632c9925f013	781	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
donatien	0:632c9925f013	782	(u16_t)flags));
donatien	0:632c9925f013	783
donatien	0:632c9925f013	784	/* Now append seg to pcb->unsent queue */
donatien	0:632c9925f013	785	if (pcb->unsent == NULL) {
donatien	0:632c9925f013	786	pcb->unsent = seg;
donatien	0:632c9925f013	787	} else {
donatien	0:632c9925f013	788	struct tcp_seg *useg;
donatien	0:632c9925f013	789	for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
donatien	0:632c9925f013	790	useg->next = seg;
donatien	0:632c9925f013	791	}
donatien	0:632c9925f013	792	#if TCP_OVERSIZE
donatien	0:632c9925f013	793	/* The new unsent tail has no space */
donatien	0:632c9925f013	794	pcb->unsent_oversize = 0;
donatien	0:632c9925f013	795	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	796
donatien	0:632c9925f013	797	/* SYN and FIN bump the sequence number */
donatien	0:632c9925f013	798	if ((flags & TCP_SYN) \|\| (flags & TCP_FIN)) {
donatien	0:632c9925f013	799	pcb->snd_lbb++;
donatien	0:632c9925f013	800	/* optlen does not influence snd_buf */
donatien	0:632c9925f013	801	pcb->snd_buf--;
donatien	0:632c9925f013	802	}
donatien	0:632c9925f013	803	if (flags & TCP_FIN) {
donatien	0:632c9925f013	804	pcb->flags \|= TF_FIN;
donatien	0:632c9925f013	805	}
donatien	0:632c9925f013	806
donatien	0:632c9925f013	807	/* update number of segments on the queues */
donatien	0:632c9925f013	808	pcb->snd_queuelen += pbuf_clen(seg->p);
donatien	0:632c9925f013	809	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
donatien	0:632c9925f013	810	if (pcb->snd_queuelen != 0) {
donatien	0:632c9925f013	811	LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
donatien	0:632c9925f013	812	pcb->unacked != NULL \|\| pcb->unsent != NULL);
donatien	0:632c9925f013	813	}
donatien	0:632c9925f013	814
donatien	0:632c9925f013	815	return ERR_OK;
donatien	0:632c9925f013	816	}
donatien	0:632c9925f013	817
donatien	0:632c9925f013	818
donatien	0:632c9925f013	819	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	820	/* Build a timestamp option (12 bytes long) at the specified options pointer)
donatien	0:632c9925f013	821	*
donatien	0:632c9925f013	822	* @param pcb tcp_pcb
donatien	0:632c9925f013	823	* @param opts option pointer where to store the timestamp option
donatien	0:632c9925f013	824	*/
donatien	0:632c9925f013	825	static void
donatien	0:632c9925f013	826	tcp_build_timestamp_option(struct tcp_pcb pcb, u32_t opts)
donatien	0:632c9925f013	827	{
donatien	0:632c9925f013	828	/* Pad with two NOP options to make everything nicely aligned */
donatien	5:dd63a1e02b1b	829	opts[0] = PP_HTONL(0x0101080A);
donatien	0:632c9925f013	830	opts[1] = htonl(sys_now());
donatien	0:632c9925f013	831	opts[2] = htonl(pcb->ts_recent);
donatien	0:632c9925f013	832	}
donatien	0:632c9925f013	833	#endif
donatien	0:632c9925f013	834
donatien	0:632c9925f013	835	/** Send an ACK without data.
donatien	0:632c9925f013	836	*
donatien	0:632c9925f013	837	* @param pcb Protocol control block for the TCP connection to send the ACK
donatien	0:632c9925f013	838	*/
donatien	0:632c9925f013	839	err_t
donatien	0:632c9925f013	840	tcp_send_empty_ack(struct tcp_pcb *pcb)
donatien	0:632c9925f013	841	{
donatien	0:632c9925f013	842	struct pbuf *p;
donatien	0:632c9925f013	843	struct tcp_hdr *tcphdr;
donatien	0:632c9925f013	844	u8_t optlen = 0;
donatien	0:632c9925f013	845
donatien	0:632c9925f013	846	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	847	if (pcb->flags & TF_TIMESTAMP) {
donatien	0:632c9925f013	848	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
donatien	0:632c9925f013	849	}
donatien	0:632c9925f013	850	#endif
donatien	0:632c9925f013	851
donatien	0:632c9925f013	852	p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
donatien	0:632c9925f013	853	if (p == NULL) {
donatien	0:632c9925f013	854	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
donatien	0:632c9925f013	855	return ERR_BUF;
donatien	0:632c9925f013	856	}
donatien	0:632c9925f013	857	tcphdr = (struct tcp_hdr *)p->payload;
donatien	0:632c9925f013	858	LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
donatien	0:632c9925f013	859	("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
donatien	0:632c9925f013	860	/* remove ACK flags from the PCB, as we send an empty ACK now */
donatien	0:632c9925f013	861	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
donatien	0:632c9925f013	862
donatien	0:632c9925f013	863	/* NB. MSS option is only sent on SYNs, so ignore it here */
donatien	0:632c9925f013	864	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	865	pcb->ts_lastacksent = pcb->rcv_nxt;
donatien	0:632c9925f013	866
donatien	0:632c9925f013	867	if (pcb->flags & TF_TIMESTAMP) {
donatien	0:632c9925f013	868	tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
donatien	0:632c9925f013	869	}
donatien	0:632c9925f013	870	#endif
donatien	0:632c9925f013	871
donatien	0:632c9925f013	872	#if CHECKSUM_GEN_TCP
donatien	0:632c9925f013	873	tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
donatien	0:632c9925f013	874	IP_PROTO_TCP, p->tot_len);
donatien	0:632c9925f013	875	#endif
donatien	0:632c9925f013	876	#if LWIP_NETIF_HWADDRHINT
donatien	0:632c9925f013	877	ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
donatien	0:632c9925f013	878	IP_PROTO_TCP, &(pcb->addr_hint));
donatien	0:632c9925f013	879	#else /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	880	ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
donatien	0:632c9925f013	881	IP_PROTO_TCP);
donatien	0:632c9925f013	882	#endif /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	883	pbuf_free(p);
donatien	0:632c9925f013	884
donatien	0:632c9925f013	885	return ERR_OK;
donatien	0:632c9925f013	886	}
donatien	0:632c9925f013	887
donatien	0:632c9925f013	888	/**
donatien	0:632c9925f013	889	* Find out what we can send and send it
donatien	0:632c9925f013	890	*
donatien	0:632c9925f013	891	* @param pcb Protocol control block for the TCP connection to send data
donatien	0:632c9925f013	892	* @return ERR_OK if data has been sent or nothing to send
donatien	0:632c9925f013	893	* another err_t on error
donatien	0:632c9925f013	894	*/
donatien	0:632c9925f013	895	err_t
donatien	0:632c9925f013	896	tcp_output(struct tcp_pcb *pcb)
donatien	0:632c9925f013	897	{
donatien	0:632c9925f013	898	struct tcp_seg seg, useg;
donatien	0:632c9925f013	899	u32_t wnd, snd_nxt;
donatien	0:632c9925f013	900	#if TCP_CWND_DEBUG
donatien	0:632c9925f013	901	s16_t i = 0;
donatien	0:632c9925f013	902	#endif /* TCP_CWND_DEBUG */
donatien	0:632c9925f013	903
donatien	0:632c9925f013	904	/* First, check if we are invoked by the TCP input processing
donatien	0:632c9925f013	905	code. If so, we do not output anything. Instead, we rely on the
donatien	0:632c9925f013	906	input processing code to call us when input processing is done
donatien	0:632c9925f013	907	with. */
donatien	0:632c9925f013	908	if (tcp_input_pcb == pcb) {
donatien	0:632c9925f013	909	return ERR_OK;
donatien	0:632c9925f013	910	}
donatien	0:632c9925f013	911
donatien	0:632c9925f013	912	wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
donatien	0:632c9925f013	913
donatien	0:632c9925f013	914	seg = pcb->unsent;
donatien	0:632c9925f013	915
donatien	0:632c9925f013	916	/* If the TF_ACK_NOW flag is set and no data will be sent (either
donatien	0:632c9925f013	917	* because the ->unsent queue is empty or because the window does
donatien	0:632c9925f013	918	* not allow it), construct an empty ACK segment and send it.
donatien	0:632c9925f013	919	*
donatien	0:632c9925f013	920	* If data is to be sent, we will just piggyback the ACK (see below).
donatien	0:632c9925f013	921	*/
donatien	0:632c9925f013	922	if (pcb->flags & TF_ACK_NOW &&
donatien	0:632c9925f013	923	(seg == NULL \|\|
donatien	0:632c9925f013	924	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
donatien	0:632c9925f013	925	return tcp_send_empty_ack(pcb);
donatien	0:632c9925f013	926	}
donatien	0:632c9925f013	927
donatien	0:632c9925f013	928	/* useg should point to last segment on unacked queue */
donatien	0:632c9925f013	929	useg = pcb->unacked;
donatien	0:632c9925f013	930	if (useg != NULL) {
donatien	0:632c9925f013	931	for (; useg->next != NULL; useg = useg->next);
donatien	0:632c9925f013	932	}
donatien	0:632c9925f013	933
donatien	0:632c9925f013	934	#if TCP_OUTPUT_DEBUG
donatien	0:632c9925f013	935	if (seg == NULL) {
donatien	0:632c9925f013	936	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
donatien	0:632c9925f013	937	(void*)pcb->unsent));
donatien	0:632c9925f013	938	}
donatien	0:632c9925f013	939	#endif /* TCP_OUTPUT_DEBUG */
donatien	0:632c9925f013	940	#if TCP_CWND_DEBUG
donatien	0:632c9925f013	941	if (seg == NULL) {
donatien	0:632c9925f013	942	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
donatien	0:632c9925f013	943	", cwnd %"U16_F", wnd %"U32_F
donatien	0:632c9925f013	944	", seg == NULL, ack %"U32_F"\n",
donatien	0:632c9925f013	945	pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
donatien	0:632c9925f013	946	} else {
donatien	0:632c9925f013	947	LWIP_DEBUGF(TCP_CWND_DEBUG,
donatien	0:632c9925f013	948	("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
donatien	0:632c9925f013	949	", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
donatien	0:632c9925f013	950	pcb->snd_wnd, pcb->cwnd, wnd,
donatien	0:632c9925f013	951	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
donatien	0:632c9925f013	952	ntohl(seg->tcphdr->seqno), pcb->lastack));
donatien	0:632c9925f013	953	}
donatien	0:632c9925f013	954	#endif /* TCP_CWND_DEBUG */
donatien	0:632c9925f013	955	/* data available and window allows it to be sent? */
donatien	0:632c9925f013	956	while (seg != NULL &&
donatien	0:632c9925f013	957	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
donatien	0:632c9925f013	958	LWIP_ASSERT("RST not expected here!",
donatien	0:632c9925f013	959	(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
donatien	0:632c9925f013	960	/* Stop sending if the nagle algorithm would prevent it
donatien	0:632c9925f013	961	* Don't stop:
donatien	0:632c9925f013	962	* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
donatien	0:632c9925f013	963	* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
donatien	0:632c9925f013	964	* either seg->next != NULL or pcb->unacked == NULL;
donatien	0:632c9925f013	965	* RST is no sent using tcp_write/tcp_output.
donatien	0:632c9925f013	966	*/
donatien	0:632c9925f013	967	if((tcp_do_output_nagle(pcb) == 0) &&
donatien	0:632c9925f013	968	((pcb->flags & (TF_NAGLEMEMERR \| TF_FIN)) == 0)){
donatien	0:632c9925f013	969	break;
donatien	0:632c9925f013	970	}
donatien	0:632c9925f013	971	#if TCP_CWND_DEBUG
donatien	0:632c9925f013	972	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\n",
donatien	0:632c9925f013	973	pcb->snd_wnd, pcb->cwnd, wnd,
donatien	0:632c9925f013	974	ntohl(seg->tcphdr->seqno) + seg->len -
donatien	0:632c9925f013	975	pcb->lastack,
donatien	0:632c9925f013	976	ntohl(seg->tcphdr->seqno), pcb->lastack, i));
donatien	0:632c9925f013	977	++i;
donatien	0:632c9925f013	978	#endif /* TCP_CWND_DEBUG */
donatien	0:632c9925f013	979
donatien	0:632c9925f013	980	pcb->unsent = seg->next;
donatien	0:632c9925f013	981
donatien	0:632c9925f013	982	if (pcb->state != SYN_SENT) {
donatien	0:632c9925f013	983	TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
donatien	0:632c9925f013	984	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
donatien	0:632c9925f013	985	}
donatien	0:632c9925f013	986
donatien	0:632c9925f013	987	tcp_output_segment(seg, pcb);
donatien	5:dd63a1e02b1b	988
donatien	0:632c9925f013	989	snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
donatien	5:dd63a1e02b1b	990
donatien	5:dd63a1e02b1b	991	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: pcb->snd_nxt was %"U32_F" seqno=%"U32_F" len=%"U32_F" new snd_nxt=%"U32_F"\n", //DG
donatien	5:dd63a1e02b1b	992	pcb->snd_nxt, ntohl(seg->tcphdr->seqno), TCP_TCPLEN(seg), snd_nxt));
donatien	5:dd63a1e02b1b	993
donatien	0:632c9925f013	994	if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
donatien	0:632c9925f013	995	pcb->snd_nxt = snd_nxt;
donatien	0:632c9925f013	996	}
donatien	0:632c9925f013	997	/* put segment on unacknowledged list if length > 0 */
donatien	0:632c9925f013	998	if (TCP_TCPLEN(seg) > 0) {
donatien	0:632c9925f013	999	seg->next = NULL;
donatien	0:632c9925f013	1000	/* unacked list is empty? */
donatien	0:632c9925f013	1001	if (pcb->unacked == NULL) {
donatien	0:632c9925f013	1002	pcb->unacked = seg;
donatien	0:632c9925f013	1003	useg = seg;
donatien	0:632c9925f013	1004	/* unacked list is not empty? */
donatien	0:632c9925f013	1005	} else {
donatien	0:632c9925f013	1006	/* In the case of fast retransmit, the packet should not go to the tail
donatien	0:632c9925f013	1007	* of the unacked queue, but rather somewhere before it. We need to check for
donatien	0:632c9925f013	1008	* this case. -STJ Jul 27, 2004 */
donatien	0:632c9925f013	1009	if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
donatien	0:632c9925f013	1010	/* add segment to before tail of unacked list, keeping the list sorted */
donatien	0:632c9925f013	1011	struct tcp_seg **cur_seg = &(pcb->unacked);
donatien	0:632c9925f013	1012	while (*cur_seg &&
donatien	0:632c9925f013	1013	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
donatien	0:632c9925f013	1014	cur_seg = &((*cur_seg)->next );
donatien	0:632c9925f013	1015	}
donatien	0:632c9925f013	1016	seg->next = (*cur_seg);
donatien	0:632c9925f013	1017	(*cur_seg) = seg;
donatien	0:632c9925f013	1018	} else {
donatien	0:632c9925f013	1019	/* add segment to tail of unacked list */
donatien	0:632c9925f013	1020	useg->next = seg;
donatien	0:632c9925f013	1021	useg = useg->next;
donatien	0:632c9925f013	1022	}
donatien	0:632c9925f013	1023	}
donatien	0:632c9925f013	1024	/* do not queue empty segments on the unacked list */
donatien	0:632c9925f013	1025	} else {
donatien	0:632c9925f013	1026	tcp_seg_free(seg);
donatien	0:632c9925f013	1027	}
donatien	0:632c9925f013	1028	seg = pcb->unsent;
donatien	0:632c9925f013	1029	}
donatien	0:632c9925f013	1030	#if TCP_OVERSIZE
donatien	0:632c9925f013	1031	if (pcb->unsent == NULL) {
donatien	0:632c9925f013	1032	/* last unsent has been removed, reset unsent_oversize */
donatien	0:632c9925f013	1033	pcb->unsent_oversize = 0;
donatien	0:632c9925f013	1034	}
donatien	0:632c9925f013	1035	#endif /* TCP_OVERSIZE */
donatien	0:632c9925f013	1036
donatien	0:632c9925f013	1037	if (seg != NULL && pcb->persist_backoff == 0 &&
donatien	0:632c9925f013	1038	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
donatien	0:632c9925f013	1039	/* prepare for persist timer */
donatien	0:632c9925f013	1040	pcb->persist_cnt = 0;
donatien	0:632c9925f013	1041	pcb->persist_backoff = 1;
donatien	0:632c9925f013	1042	}
donatien	0:632c9925f013	1043
donatien	0:632c9925f013	1044	pcb->flags &= ~TF_NAGLEMEMERR;
donatien	0:632c9925f013	1045	return ERR_OK;
donatien	0:632c9925f013	1046	}
donatien	0:632c9925f013	1047
donatien	0:632c9925f013	1048	/**
donatien	0:632c9925f013	1049	* Called by tcp_output() to actually send a TCP segment over IP.
donatien	0:632c9925f013	1050	*
donatien	0:632c9925f013	1051	* @param seg the tcp_seg to send
donatien	0:632c9925f013	1052	* @param pcb the tcp_pcb for the TCP connection used to send the segment
donatien	0:632c9925f013	1053	*/
donatien	0:632c9925f013	1054	static void
donatien	0:632c9925f013	1055	tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb)
donatien	0:632c9925f013	1056	{
donatien	0:632c9925f013	1057	u16_t len;
donatien	0:632c9925f013	1058	struct netif *netif;
donatien	0:632c9925f013	1059	u32_t *opts;
donatien	0:632c9925f013	1060
donatien	0:632c9925f013	1061	/** @bug Exclude retransmitted segments from this count. */
donatien	0:632c9925f013	1062	snmp_inc_tcpoutsegs();
donatien	0:632c9925f013	1063
donatien	0:632c9925f013	1064	/* The TCP header has already been constructed, but the ackno and
donatien	0:632c9925f013	1065	wnd fields remain. */
donatien	0:632c9925f013	1066	seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
donatien	0:632c9925f013	1067
donatien	0:632c9925f013	1068	/* advertise our receive window size in this TCP segment */
donatien	0:632c9925f013	1069	seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
donatien	0:632c9925f013	1070
donatien	0:632c9925f013	1071	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
donatien	0:632c9925f013	1072
donatien	0:632c9925f013	1073	/* Add any requested options. NB MSS option is only set on SYN
donatien	0:632c9925f013	1074	packets, so ignore it here */
donatien	0:632c9925f013	1075	LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)(seg->tcphdr + 1) % 4) == 0);
donatien	0:632c9925f013	1076	opts = (u32_t )(void )(seg->tcphdr + 1);
donatien	0:632c9925f013	1077	if (seg->flags & TF_SEG_OPTS_MSS) {
donatien	0:632c9925f013	1078	TCP_BUILD_MSS_OPTION(*opts);
donatien	0:632c9925f013	1079	opts += 1;
donatien	0:632c9925f013	1080	}
donatien	0:632c9925f013	1081	#if LWIP_TCP_TIMESTAMPS
donatien	0:632c9925f013	1082	pcb->ts_lastacksent = pcb->rcv_nxt;
donatien	0:632c9925f013	1083
donatien	0:632c9925f013	1084	if (seg->flags & TF_SEG_OPTS_TS) {
donatien	0:632c9925f013	1085	tcp_build_timestamp_option(pcb, opts);
donatien	0:632c9925f013	1086	opts += 3;
donatien	0:632c9925f013	1087	}
donatien	0:632c9925f013	1088	#endif
donatien	0:632c9925f013	1089
donatien	0:632c9925f013	1090	/* If we don't have a local IP address, we get one by
donatien	0:632c9925f013	1091	calling ip_route(). */
donatien	0:632c9925f013	1092	if (ip_addr_isany(&(pcb->local_ip))) {
donatien	0:632c9925f013	1093	netif = ip_route(&(pcb->remote_ip));
donatien	0:632c9925f013	1094	if (netif == NULL) {
donatien	0:632c9925f013	1095	return;
donatien	0:632c9925f013	1096	}
donatien	0:632c9925f013	1097	ip_addr_copy(pcb->local_ip, netif->ip_addr);
donatien	0:632c9925f013	1098	}
donatien	0:632c9925f013	1099
donatien	0:632c9925f013	1100	/* Set retransmission timer running if it is not currently enabled */
donatien	0:632c9925f013	1101	if(pcb->rtime == -1) {
donatien	0:632c9925f013	1102	pcb->rtime = 0;
donatien	0:632c9925f013	1103	}
donatien	0:632c9925f013	1104
donatien	0:632c9925f013	1105	if (pcb->rttest == 0) {
donatien	0:632c9925f013	1106	pcb->rttest = tcp_ticks;
donatien	0:632c9925f013	1107	pcb->rtseq = ntohl(seg->tcphdr->seqno);
donatien	0:632c9925f013	1108
donatien	0:632c9925f013	1109	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
donatien	0:632c9925f013	1110	}
donatien	0:632c9925f013	1111	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
donatien	0:632c9925f013	1112	htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
donatien	0:632c9925f013	1113	seg->len));
donatien	0:632c9925f013	1114
donatien	0:632c9925f013	1115	len = (u16_t)((u8_t )seg->tcphdr - (u8_t )seg->p->payload);
donatien	0:632c9925f013	1116
donatien	0:632c9925f013	1117	seg->p->len -= len;
donatien	0:632c9925f013	1118	seg->p->tot_len -= len;
donatien	0:632c9925f013	1119
donatien	0:632c9925f013	1120	seg->p->payload = seg->tcphdr;
donatien	0:632c9925f013	1121
donatien	0:632c9925f013	1122	seg->tcphdr->chksum = 0;
donatien	0:632c9925f013	1123	#if CHECKSUM_GEN_TCP
donatien	0:632c9925f013	1124	#if TCP_CHECKSUM_ON_COPY
donatien	0:632c9925f013	1125	{
donatien	0:632c9925f013	1126	u32_t acc;
donatien	0:632c9925f013	1127	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
donatien	0:632c9925f013	1128	u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
donatien	0:632c9925f013	1129	&(pcb->remote_ip),
donatien	0:632c9925f013	1130	IP_PROTO_TCP, seg->p->tot_len);
donatien	0:632c9925f013	1131	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
donatien	0:632c9925f013	1132	if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
donatien	0:632c9925f013	1133	LWIP_ASSERT("data included but not checksummed",
donatien	0:632c9925f013	1134	seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
donatien	0:632c9925f013	1135	}
donatien	0:632c9925f013	1136
donatien	0:632c9925f013	1137	/* rebuild TCP header checksum (TCP header changes for retransmissions!) */
donatien	0:632c9925f013	1138	acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
donatien	0:632c9925f013	1139	&(pcb->remote_ip),
donatien	0:632c9925f013	1140	IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
donatien	0:632c9925f013	1141	/* add payload checksum */
donatien	0:632c9925f013	1142	if (seg->chksum_swapped) {
donatien	0:632c9925f013	1143	seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
donatien	0:632c9925f013	1144	seg->chksum_swapped = 0;
donatien	0:632c9925f013	1145	}
donatien	0:632c9925f013	1146	acc += (u16_t)~(seg->chksum);
donatien	0:632c9925f013	1147	seg->tcphdr->chksum = FOLD_U32T(acc);
donatien	0:632c9925f013	1148	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
donatien	0:632c9925f013	1149	if (chksum_slow != seg->tcphdr->chksum) {
donatien	0:632c9925f013	1150	LWIP_DEBUGF(TCP_DEBUG \| LWIP_DBG_LEVEL_WARNING,
donatien	0:632c9925f013	1151	("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
donatien	0:632c9925f013	1152	seg->tcphdr->chksum, chksum_slow));
donatien	0:632c9925f013	1153	seg->tcphdr->chksum = chksum_slow;
donatien	0:632c9925f013	1154	}
donatien	0:632c9925f013	1155	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
donatien	0:632c9925f013	1156	}
donatien	0:632c9925f013	1157	#else /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	1158	seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
donatien	0:632c9925f013	1159	&(pcb->remote_ip),
donatien	0:632c9925f013	1160	IP_PROTO_TCP, seg->p->tot_len);
donatien	0:632c9925f013	1161	#endif /* TCP_CHECKSUM_ON_COPY */
donatien	0:632c9925f013	1162	#endif /* CHECKSUM_GEN_TCP */
donatien	0:632c9925f013	1163	TCP_STATS_INC(tcp.xmit);
donatien	5:dd63a1e02b1b	1164
donatien	5:dd63a1e02b1b	1165	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: Before ip_out seqno = %"U32_F"\n",
donatien	5:dd63a1e02b1b	1166	htonl(seg->tcphdr->seqno))); //DG
donatien	0:632c9925f013	1167
donatien	0:632c9925f013	1168	#if LWIP_NETIF_HWADDRHINT
donatien	0:632c9925f013	1169	ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
donatien	0:632c9925f013	1170	IP_PROTO_TCP, &(pcb->addr_hint));
donatien	0:632c9925f013	1171	#else /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	1172	ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
donatien	0:632c9925f013	1173	IP_PROTO_TCP);
donatien	0:632c9925f013	1174	#endif /* LWIP_NETIF_HWADDRHINT*/
donatien	5:dd63a1e02b1b	1175
donatien	5:dd63a1e02b1b	1176	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: After ip_out seqno = %"U32_F"\n",
donatien	5:dd63a1e02b1b	1177	htonl(seg->tcphdr->seqno))); //DG
donatien	5:dd63a1e02b1b	1178
donatien	5:dd63a1e02b1b	1179
donatien	0:632c9925f013	1180	}
donatien	0:632c9925f013	1181
donatien	0:632c9925f013	1182	/**
donatien	0:632c9925f013	1183	* Send a TCP RESET packet (empty segment with RST flag set) either to
donatien	0:632c9925f013	1184	* abort a connection or to show that there is no matching local connection
donatien	0:632c9925f013	1185	* for a received segment.
donatien	0:632c9925f013	1186	*
donatien	0:632c9925f013	1187	* Called by tcp_abort() (to abort a local connection), tcp_input() (if no
donatien	0:632c9925f013	1188	* matching local pcb was found), tcp_listen_input() (if incoming segment
donatien	0:632c9925f013	1189	* has ACK flag set) and tcp_process() (received segment in the wrong state)
donatien	0:632c9925f013	1190	*
donatien	0:632c9925f013	1191	* Since a RST segment is in most cases not sent for an active connection,
donatien	0:632c9925f013	1192	* tcp_rst() has a number of arguments that are taken from a tcp_pcb for
donatien	0:632c9925f013	1193	* most other segment output functions.
donatien	0:632c9925f013	1194	*
donatien	0:632c9925f013	1195	* @param seqno the sequence number to use for the outgoing segment
donatien	0:632c9925f013	1196	* @param ackno the acknowledge number to use for the outgoing segment
donatien	0:632c9925f013	1197	* @param local_ip the local IP address to send the segment from
donatien	0:632c9925f013	1198	* @param remote_ip the remote IP address to send the segment to
donatien	0:632c9925f013	1199	* @param local_port the local TCP port to send the segment from
donatien	0:632c9925f013	1200	* @param remote_port the remote TCP port to send the segment to
donatien	0:632c9925f013	1201	*/
donatien	0:632c9925f013	1202	void
donatien	0:632c9925f013	1203	tcp_rst(u32_t seqno, u32_t ackno,
donatien	0:632c9925f013	1204	ip_addr_t local_ip, ip_addr_t remote_ip,
donatien	0:632c9925f013	1205	u16_t local_port, u16_t remote_port)
donatien	0:632c9925f013	1206	{
donatien	0:632c9925f013	1207	struct pbuf *p;
donatien	0:632c9925f013	1208	struct tcp_hdr *tcphdr;
donatien	0:632c9925f013	1209	p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
donatien	0:632c9925f013	1210	if (p == NULL) {
donatien	0:632c9925f013	1211	LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
donatien	0:632c9925f013	1212	return;
donatien	0:632c9925f013	1213	}
donatien	0:632c9925f013	1214	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
donatien	0:632c9925f013	1215	(p->len >= sizeof(struct tcp_hdr)));
donatien	0:632c9925f013	1216
donatien	0:632c9925f013	1217	tcphdr = (struct tcp_hdr *)p->payload;
donatien	0:632c9925f013	1218	tcphdr->src = htons(local_port);
donatien	0:632c9925f013	1219	tcphdr->dest = htons(remote_port);
donatien	0:632c9925f013	1220	tcphdr->seqno = htonl(seqno);
donatien	0:632c9925f013	1221	tcphdr->ackno = htonl(ackno);
donatien	0:632c9925f013	1222	TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST \| TCP_ACK);
donatien	5:dd63a1e02b1b	1223	tcphdr->wnd = PP_HTONS(TCP_WND);
donatien	0:632c9925f013	1224	tcphdr->chksum = 0;
donatien	0:632c9925f013	1225	tcphdr->urgp = 0;
donatien	0:632c9925f013	1226
donatien	0:632c9925f013	1227	#if CHECKSUM_GEN_TCP
donatien	0:632c9925f013	1228	tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
donatien	0:632c9925f013	1229	IP_PROTO_TCP, p->tot_len);
donatien	0:632c9925f013	1230	#endif
donatien	0:632c9925f013	1231	TCP_STATS_INC(tcp.xmit);
donatien	0:632c9925f013	1232	snmp_inc_tcpoutrsts();
donatien	0:632c9925f013	1233	/* Send output with hardcoded TTL since we have no access to the pcb */
donatien	0:632c9925f013	1234	ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
donatien	0:632c9925f013	1235	pbuf_free(p);
donatien	0:632c9925f013	1236	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
donatien	0:632c9925f013	1237	}
donatien	0:632c9925f013	1238
donatien	0:632c9925f013	1239	/**
donatien	0:632c9925f013	1240	* Requeue all unacked segments for retransmission
donatien	0:632c9925f013	1241	*
donatien	0:632c9925f013	1242	* Called by tcp_slowtmr() for slow retransmission.
donatien	0:632c9925f013	1243	*
donatien	0:632c9925f013	1244	* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
donatien	0:632c9925f013	1245	*/
donatien	0:632c9925f013	1246	void
donatien	0:632c9925f013	1247	tcp_rexmit_rto(struct tcp_pcb *pcb)
donatien	0:632c9925f013	1248	{
donatien	0:632c9925f013	1249	struct tcp_seg *seg;
donatien	0:632c9925f013	1250
donatien	0:632c9925f013	1251	if (pcb->unacked == NULL) {
donatien	0:632c9925f013	1252	return;
donatien	0:632c9925f013	1253	}
donatien	0:632c9925f013	1254
donatien	0:632c9925f013	1255	/* Move all unacked segments to the head of the unsent queue */
donatien	0:632c9925f013	1256	for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
donatien	0:632c9925f013	1257	/* concatenate unsent queue after unacked queue */
donatien	0:632c9925f013	1258	seg->next = pcb->unsent;
donatien	0:632c9925f013	1259	/* unsent queue is the concatenated queue (of unacked, unsent) */
donatien	0:632c9925f013	1260	pcb->unsent = pcb->unacked;
donatien	0:632c9925f013	1261	/* unacked queue is now empty */
donatien	0:632c9925f013	1262	pcb->unacked = NULL;
donatien	0:632c9925f013	1263
donatien	0:632c9925f013	1264	/* increment number of retransmissions */
donatien	0:632c9925f013	1265	++pcb->nrtx;
donatien	0:632c9925f013	1266
donatien	0:632c9925f013	1267	/* Don't take any RTT measurements after retransmitting. */
donatien	0:632c9925f013	1268	pcb->rttest = 0;
donatien	0:632c9925f013	1269
donatien	0:632c9925f013	1270	/* Do the actual retransmission */
donatien	0:632c9925f013	1271	tcp_output(pcb);
donatien	0:632c9925f013	1272	}
donatien	0:632c9925f013	1273
donatien	0:632c9925f013	1274	/**
donatien	0:632c9925f013	1275	* Requeue the first unacked segment for retransmission
donatien	0:632c9925f013	1276	*
donatien	0:632c9925f013	1277	* Called by tcp_receive() for fast retramsmit.
donatien	0:632c9925f013	1278	*
donatien	0:632c9925f013	1279	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
donatien	0:632c9925f013	1280	*/
donatien	0:632c9925f013	1281	void
donatien	0:632c9925f013	1282	tcp_rexmit(struct tcp_pcb *pcb)
donatien	0:632c9925f013	1283	{
donatien	0:632c9925f013	1284	struct tcp_seg *seg;
donatien	0:632c9925f013	1285	struct tcp_seg **cur_seg;
donatien	0:632c9925f013	1286
donatien	0:632c9925f013	1287	if (pcb->unacked == NULL) {
donatien	0:632c9925f013	1288	return;
donatien	0:632c9925f013	1289	}
donatien	0:632c9925f013	1290
donatien	0:632c9925f013	1291	/* Move the first unacked segment to the unsent queue */
donatien	0:632c9925f013	1292	/* Keep the unsent queue sorted. */
donatien	0:632c9925f013	1293	seg = pcb->unacked;
donatien	0:632c9925f013	1294	pcb->unacked = seg->next;
donatien	0:632c9925f013	1295
donatien	0:632c9925f013	1296	cur_seg = &(pcb->unsent);
donatien	0:632c9925f013	1297	while (*cur_seg &&
donatien	0:632c9925f013	1298	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
donatien	0:632c9925f013	1299	cur_seg = &((*cur_seg)->next );
donatien	0:632c9925f013	1300	}
donatien	0:632c9925f013	1301	seg->next = *cur_seg;
donatien	0:632c9925f013	1302	*cur_seg = seg;
donatien	0:632c9925f013	1303
donatien	0:632c9925f013	1304	++pcb->nrtx;
donatien	0:632c9925f013	1305
donatien	0:632c9925f013	1306	/* Don't take any rtt measurements after retransmitting. */
donatien	0:632c9925f013	1307	pcb->rttest = 0;
donatien	0:632c9925f013	1308
donatien	0:632c9925f013	1309	/* Do the actual retransmission. */
donatien	0:632c9925f013	1310	snmp_inc_tcpretranssegs();
donatien	0:632c9925f013	1311	/* No need to call tcp_output: we are always called from tcp_input()
donatien	0:632c9925f013	1312	and thus tcp_output directly returns. */
donatien	0:632c9925f013	1313	}
donatien	0:632c9925f013	1314
donatien	0:632c9925f013	1315
donatien	0:632c9925f013	1316	/**
donatien	0:632c9925f013	1317	* Handle retransmission after three dupacks received
donatien	0:632c9925f013	1318	*
donatien	0:632c9925f013	1319	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
donatien	0:632c9925f013	1320	*/
donatien	0:632c9925f013	1321	void
donatien	0:632c9925f013	1322	tcp_rexmit_fast(struct tcp_pcb *pcb)
donatien	0:632c9925f013	1323	{
donatien	0:632c9925f013	1324	if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
donatien	0:632c9925f013	1325	/* This is fast retransmit. Retransmit the first unacked segment. */
donatien	0:632c9925f013	1326	LWIP_DEBUGF(TCP_FR_DEBUG,
donatien	0:632c9925f013	1327	("tcp_receive: dupacks %"U16_F" (%"U32_F
donatien	0:632c9925f013	1328	"), fast retransmit %"U32_F"\n",
donatien	0:632c9925f013	1329	(u16_t)pcb->dupacks, pcb->lastack,
donatien	0:632c9925f013	1330	ntohl(pcb->unacked->tcphdr->seqno)));
donatien	0:632c9925f013	1331	tcp_rexmit(pcb);
donatien	0:632c9925f013	1332
donatien	0:632c9925f013	1333	/* Set ssthresh to half of the minimum of the current
donatien	0:632c9925f013	1334	* cwnd and the advertised window */
donatien	0:632c9925f013	1335	if (pcb->cwnd > pcb->snd_wnd) {
donatien	0:632c9925f013	1336	pcb->ssthresh = pcb->snd_wnd / 2;
donatien	0:632c9925f013	1337	} else {
donatien	0:632c9925f013	1338	pcb->ssthresh = pcb->cwnd / 2;
donatien	0:632c9925f013	1339	}
donatien	0:632c9925f013	1340
donatien	0:632c9925f013	1341	/* The minimum value for ssthresh should be 2 MSS */
donatien	0:632c9925f013	1342	if (pcb->ssthresh < 2*pcb->mss) {
donatien	0:632c9925f013	1343	LWIP_DEBUGF(TCP_FR_DEBUG,
donatien	0:632c9925f013	1344	("tcp_receive: The minimum value for ssthresh %"U16_F
donatien	0:632c9925f013	1345	" should be min 2 mss %"U16_F"...\n",
donatien	0:632c9925f013	1346	pcb->ssthresh, 2*pcb->mss));
donatien	0:632c9925f013	1347	pcb->ssthresh = 2*pcb->mss;
donatien	0:632c9925f013	1348	}
donatien	0:632c9925f013	1349
donatien	0:632c9925f013	1350	pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
donatien	0:632c9925f013	1351	pcb->flags \|= TF_INFR;
donatien	0:632c9925f013	1352	}
donatien	0:632c9925f013	1353	}
donatien	0:632c9925f013	1354
donatien	0:632c9925f013	1355
donatien	0:632c9925f013	1356	/**
donatien	0:632c9925f013	1357	* Send keepalive packets to keep a connection active although
donatien	0:632c9925f013	1358	* no data is sent over it.
donatien	0:632c9925f013	1359	*
donatien	0:632c9925f013	1360	* Called by tcp_slowtmr()
donatien	0:632c9925f013	1361	*
donatien	0:632c9925f013	1362	* @param pcb the tcp_pcb for which to send a keepalive packet
donatien	0:632c9925f013	1363	*/
donatien	0:632c9925f013	1364	void
donatien	0:632c9925f013	1365	tcp_keepalive(struct tcp_pcb *pcb)
donatien	0:632c9925f013	1366	{
donatien	0:632c9925f013	1367	struct pbuf *p;
donatien	0:632c9925f013	1368	struct tcp_hdr *tcphdr;
donatien	0:632c9925f013	1369
donatien	0:632c9925f013	1370	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
donatien	0:632c9925f013	1371	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
donatien	0:632c9925f013	1372	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
donatien	0:632c9925f013	1373
donatien	0:632c9925f013	1374	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
donatien	0:632c9925f013	1375	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
donatien	0:632c9925f013	1376
donatien	0:632c9925f013	1377	p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
donatien	0:632c9925f013	1378	if(p == NULL) {
donatien	0:632c9925f013	1379	LWIP_DEBUGF(TCP_DEBUG,
donatien	0:632c9925f013	1380	("tcp_keepalive: could not allocate memory for pbuf\n"));
donatien	0:632c9925f013	1381	return;
donatien	0:632c9925f013	1382	}
donatien	0:632c9925f013	1383	tcphdr = (struct tcp_hdr *)p->payload;
donatien	0:632c9925f013	1384
donatien	0:632c9925f013	1385	#if CHECKSUM_GEN_TCP
donatien	0:632c9925f013	1386	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
donatien	0:632c9925f013	1387	IP_PROTO_TCP, p->tot_len);
donatien	0:632c9925f013	1388	#endif
donatien	0:632c9925f013	1389	TCP_STATS_INC(tcp.xmit);
donatien	0:632c9925f013	1390
donatien	0:632c9925f013	1391	/* Send output to IP */
donatien	0:632c9925f013	1392	#if LWIP_NETIF_HWADDRHINT
donatien	0:632c9925f013	1393	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
donatien	0:632c9925f013	1394	&(pcb->addr_hint));
donatien	0:632c9925f013	1395	#else /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	1396	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
donatien	0:632c9925f013	1397	#endif /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	1398
donatien	0:632c9925f013	1399	pbuf_free(p);
donatien	0:632c9925f013	1400
donatien	0:632c9925f013	1401	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
donatien	0:632c9925f013	1402	pcb->snd_nxt - 1, pcb->rcv_nxt));
donatien	0:632c9925f013	1403	}
donatien	0:632c9925f013	1404
donatien	0:632c9925f013	1405
donatien	0:632c9925f013	1406	/**
donatien	0:632c9925f013	1407	* Send persist timer zero-window probes to keep a connection active
donatien	0:632c9925f013	1408	* when a window update is lost.
donatien	0:632c9925f013	1409	*
donatien	0:632c9925f013	1410	* Called by tcp_slowtmr()
donatien	0:632c9925f013	1411	*
donatien	0:632c9925f013	1412	* @param pcb the tcp_pcb for which to send a zero-window probe packet
donatien	0:632c9925f013	1413	*/
donatien	0:632c9925f013	1414	void
donatien	0:632c9925f013	1415	tcp_zero_window_probe(struct tcp_pcb *pcb)
donatien	0:632c9925f013	1416	{
donatien	0:632c9925f013	1417	struct pbuf *p;
donatien	0:632c9925f013	1418	struct tcp_hdr *tcphdr;
donatien	0:632c9925f013	1419	struct tcp_seg *seg;
donatien	0:632c9925f013	1420	u16_t len;
donatien	0:632c9925f013	1421	u8_t is_fin;
donatien	0:632c9925f013	1422
donatien	0:632c9925f013	1423	LWIP_DEBUGF(TCP_DEBUG,
donatien	0:632c9925f013	1424	("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
donatien	0:632c9925f013	1425	U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
donatien	0:632c9925f013	1426	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
donatien	0:632c9925f013	1427	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
donatien	0:632c9925f013	1428
donatien	0:632c9925f013	1429	LWIP_DEBUGF(TCP_DEBUG,
donatien	0:632c9925f013	1430	("tcp_zero_window_probe: tcp_ticks %"U32_F
donatien	0:632c9925f013	1431	" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
donatien	0:632c9925f013	1432	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
donatien	0:632c9925f013	1433
donatien	0:632c9925f013	1434	seg = pcb->unacked;
donatien	0:632c9925f013	1435
donatien	0:632c9925f013	1436	if(seg == NULL) {
donatien	0:632c9925f013	1437	seg = pcb->unsent;
donatien	0:632c9925f013	1438	}
donatien	0:632c9925f013	1439	if(seg == NULL) {
donatien	0:632c9925f013	1440	return;
donatien	0:632c9925f013	1441	}
donatien	0:632c9925f013	1442
donatien	0:632c9925f013	1443	is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
donatien	0:632c9925f013	1444	/* we want to send one seqno: either FIN or data (no options) */
donatien	0:632c9925f013	1445	len = is_fin ? 0 : 1;
donatien	0:632c9925f013	1446
donatien	0:632c9925f013	1447	p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
donatien	0:632c9925f013	1448	if(p == NULL) {
donatien	0:632c9925f013	1449	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
donatien	0:632c9925f013	1450	return;
donatien	0:632c9925f013	1451	}
donatien	0:632c9925f013	1452	tcphdr = (struct tcp_hdr *)p->payload;
donatien	0:632c9925f013	1453
donatien	0:632c9925f013	1454	if (is_fin) {
donatien	0:632c9925f013	1455	/* FIN segment, no data */
donatien	0:632c9925f013	1456	TCPH_FLAGS_SET(tcphdr, TCP_ACK \| TCP_FIN);
donatien	0:632c9925f013	1457	} else {
donatien	0:632c9925f013	1458	/* Data segment, copy in one byte from the head of the unacked queue */
donatien	0:632c9925f013	1459	((char )p->payload + TCP_HLEN) = (char )seg->dataptr;
donatien	0:632c9925f013	1460	}
donatien	0:632c9925f013	1461
donatien	0:632c9925f013	1462	#if CHECKSUM_GEN_TCP
donatien	0:632c9925f013	1463	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
donatien	0:632c9925f013	1464	IP_PROTO_TCP, p->tot_len);
donatien	0:632c9925f013	1465	#endif
donatien	0:632c9925f013	1466	TCP_STATS_INC(tcp.xmit);
donatien	0:632c9925f013	1467
donatien	0:632c9925f013	1468	/* Send output to IP */
donatien	0:632c9925f013	1469	#if LWIP_NETIF_HWADDRHINT
donatien	0:632c9925f013	1470	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
donatien	0:632c9925f013	1471	&(pcb->addr_hint));
donatien	0:632c9925f013	1472	#else /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	1473	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
donatien	0:632c9925f013	1474	#endif /* LWIP_NETIF_HWADDRHINT*/
donatien	0:632c9925f013	1475
donatien	0:632c9925f013	1476	pbuf_free(p);
donatien	0:632c9925f013	1477
donatien	0:632c9925f013	1478	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
donatien	0:632c9925f013	1479	" ackno %"U32_F".\n",
donatien	0:632c9925f013	1480	pcb->snd_nxt - 1, pcb->rcv_nxt));
donatien	0:632c9925f013	1481	}
donatien	0:632c9925f013	1482	#endif /* LWIP_TCP */

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Type:	Program
Created:	11 Jun 2010
Imports:	2654
Forks:	0
Commits:	12
Dependents:	3
Dependencies:	0
Followers:	13

This repository is Public (Unlisted).

lwip/core/tcp_out.c@11:da4498f591ee, 2010-08-05 (annotated)

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