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lwip/core/tcp_out.c@0:350011bf8be7, 2010-11-23 (annotated)

Committer:: simon
Date:: Tue Nov 23 14:15:36 2010 +0000
Revision:: 0:350011bf8be7

Experimental version for testing UDP

Who changed what in which revision?

User	Revision	Line number	New contents of line
simon	0:350011bf8be7	1	/**
simon	0:350011bf8be7	2	* @file
simon	0:350011bf8be7	3	* Transmission Control Protocol, outgoing traffic
simon	0:350011bf8be7	4	*
simon	0:350011bf8be7	5	* The output functions of TCP.
simon	0:350011bf8be7	6	*
simon	0:350011bf8be7	7	*/
simon	0:350011bf8be7	8
simon	0:350011bf8be7	9	/*
simon	0:350011bf8be7	10	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
simon	0:350011bf8be7	11	* All rights reserved.
simon	0:350011bf8be7	12	*
simon	0:350011bf8be7	13	* Redistribution and use in source and binary forms, with or without modification,
simon	0:350011bf8be7	14	* are permitted provided that the following conditions are met:
simon	0:350011bf8be7	15	*
simon	0:350011bf8be7	16	* 1. Redistributions of source code must retain the above copyright notice,
simon	0:350011bf8be7	17	* this list of conditions and the following disclaimer.
simon	0:350011bf8be7	18	* 2. Redistributions in binary form must reproduce the above copyright notice,
simon	0:350011bf8be7	19	* this list of conditions and the following disclaimer in the documentation
simon	0:350011bf8be7	20	* and/or other materials provided with the distribution.
simon	0:350011bf8be7	21	* 3. The name of the author may not be used to endorse or promote products
simon	0:350011bf8be7	22	* derived from this software without specific prior written permission.
simon	0:350011bf8be7	23	*
simon	0:350011bf8be7	24	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
simon	0:350011bf8be7	25	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
simon	0:350011bf8be7	26	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
simon	0:350011bf8be7	27	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
simon	0:350011bf8be7	28	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
simon	0:350011bf8be7	29	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
simon	0:350011bf8be7	30	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
simon	0:350011bf8be7	31	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
simon	0:350011bf8be7	32	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
simon	0:350011bf8be7	33	* OF SUCH DAMAGE.
simon	0:350011bf8be7	34	*
simon	0:350011bf8be7	35	* This file is part of the lwIP TCP/IP stack.
simon	0:350011bf8be7	36	*
simon	0:350011bf8be7	37	* Author: Adam Dunkels <adam@sics.se>
simon	0:350011bf8be7	38	*
simon	0:350011bf8be7	39	*/
simon	0:350011bf8be7	40
simon	0:350011bf8be7	41	#include "lwip/opt.h"
simon	0:350011bf8be7	42
simon	0:350011bf8be7	43	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
simon	0:350011bf8be7	44
simon	0:350011bf8be7	45	#include "lwip/tcp_impl.h"
simon	0:350011bf8be7	46	#include "lwip/def.h"
simon	0:350011bf8be7	47	#include "lwip/mem.h"
simon	0:350011bf8be7	48	#include "lwip/memp.h"
simon	0:350011bf8be7	49	#include "lwip/sys.h"
simon	0:350011bf8be7	50	#include "lwip/ip_addr.h"
simon	0:350011bf8be7	51	#include "lwip/netif.h"
simon	0:350011bf8be7	52	#include "lwip/inet_chksum.h"
simon	0:350011bf8be7	53	#include "lwip/stats.h"
simon	0:350011bf8be7	54	#include "lwip/snmp.h"
simon	0:350011bf8be7	55
simon	0:350011bf8be7	56	#include <string.h>
simon	0:350011bf8be7	57
simon	0:350011bf8be7	58	/* Define some copy-macros for checksum-on-copy so that the code looks
simon	0:350011bf8be7	59	nicer by preventing too many ifdef's. */
simon	0:350011bf8be7	60	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	61	#define TCP_DATA_COPY(dst, src, len, seg) do { \
simon	0:350011bf8be7	62	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
simon	0:350011bf8be7	63	len, &seg->chksum, &seg->chksum_swapped); \
simon	0:350011bf8be7	64	seg->flags \|= TF_SEG_DATA_CHECKSUMMED; } while(0)
simon	0:350011bf8be7	65	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
simon	0:350011bf8be7	66	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
simon	0:350011bf8be7	67	#else /* TCP_CHECKSUM_ON_COPY*/
simon	0:350011bf8be7	68	#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
simon	0:350011bf8be7	69	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
simon	0:350011bf8be7	70	#endif /* TCP_CHECKSUM_ON_COPY*/
simon	0:350011bf8be7	71
simon	0:350011bf8be7	72	/** Define this to 1 for an extra check that the output checksum is valid
simon	0:350011bf8be7	73	* (usefule when the checksum is generated by the application, not the stack) */
simon	0:350011bf8be7	74	#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
simon	0:350011bf8be7	75	#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
simon	0:350011bf8be7	76	#endif
simon	0:350011bf8be7	77
simon	0:350011bf8be7	78	/* Forward declarations.*/
simon	0:350011bf8be7	79	static void tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb);
simon	0:350011bf8be7	80
simon	0:350011bf8be7	81	/** Allocate a pbuf and create a tcphdr at p->payload, used for output
simon	0:350011bf8be7	82	* functions other than the default tcp_output -> tcp_output_segment
simon	0:350011bf8be7	83	* (e.g. tcp_send_empty_ack, etc.)
simon	0:350011bf8be7	84	*
simon	0:350011bf8be7	85	* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
simon	0:350011bf8be7	86	* @param optlen length of header-options
simon	0:350011bf8be7	87	* @param datalen length of tcp data to reserve in pbuf
simon	0:350011bf8be7	88	* @param seqno_be seqno in network byte order (big-endian)
simon	0:350011bf8be7	89	* @return pbuf with p->payload being the tcp_hdr
simon	0:350011bf8be7	90	*/
simon	0:350011bf8be7	91	static struct pbuf *
simon	0:350011bf8be7	92	tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
simon	0:350011bf8be7	93	u32_t seqno_be /* already in network byte order */)
simon	0:350011bf8be7	94	{
simon	0:350011bf8be7	95	struct tcp_hdr *tcphdr;
simon	0:350011bf8be7	96	struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
simon	0:350011bf8be7	97	if (p != NULL) {
simon	0:350011bf8be7	98	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
simon	0:350011bf8be7	99	(p->len >= TCP_HLEN + optlen));
simon	0:350011bf8be7	100	tcphdr = (struct tcp_hdr *)p->payload;
simon	0:350011bf8be7	101	tcphdr->src = htons(pcb->local_port);
simon	0:350011bf8be7	102	tcphdr->dest = htons(pcb->remote_port);
simon	0:350011bf8be7	103	tcphdr->seqno = seqno_be;
simon	0:350011bf8be7	104	tcphdr->ackno = htonl(pcb->rcv_nxt);
simon	0:350011bf8be7	105	TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
simon	0:350011bf8be7	106	tcphdr->wnd = htons(pcb->rcv_ann_wnd);
simon	0:350011bf8be7	107	tcphdr->chksum = 0;
simon	0:350011bf8be7	108	tcphdr->urgp = 0;
simon	0:350011bf8be7	109
simon	0:350011bf8be7	110	/* If we're sending a packet, update the announced right window edge */
simon	0:350011bf8be7	111	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
simon	0:350011bf8be7	112	}
simon	0:350011bf8be7	113	return p;
simon	0:350011bf8be7	114	}
simon	0:350011bf8be7	115
simon	0:350011bf8be7	116	/**
simon	0:350011bf8be7	117	* Called by tcp_close() to send a segment including FIN flag but not data.
simon	0:350011bf8be7	118	*
simon	0:350011bf8be7	119	* @param pcb the tcp_pcb over which to send a segment
simon	0:350011bf8be7	120	* @return ERR_OK if sent, another err_t otherwise
simon	0:350011bf8be7	121	*/
simon	0:350011bf8be7	122	err_t
simon	0:350011bf8be7	123	tcp_send_fin(struct tcp_pcb *pcb)
simon	0:350011bf8be7	124	{
simon	0:350011bf8be7	125	/* first, try to add the fin to the last unsent segment */
simon	0:350011bf8be7	126	if (pcb->unsent != NULL) {
simon	0:350011bf8be7	127	struct tcp_seg *last_unsent;
simon	0:350011bf8be7	128	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
simon	0:350011bf8be7	129	last_unsent = last_unsent->next);
simon	0:350011bf8be7	130
simon	0:350011bf8be7	131	if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN \| TCP_FIN \| TCP_RST)) == 0) {
simon	0:350011bf8be7	132	/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
simon	0:350011bf8be7	133	TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
simon	0:350011bf8be7	134	return ERR_OK;
simon	0:350011bf8be7	135	}
simon	0:350011bf8be7	136	}
simon	0:350011bf8be7	137	/* no data, no length, flags, copy=1, no optdata */
simon	0:350011bf8be7	138	return tcp_enqueue_flags(pcb, TCP_FIN);
simon	0:350011bf8be7	139	}
simon	0:350011bf8be7	140
simon	0:350011bf8be7	141	/**
simon	0:350011bf8be7	142	* Create a TCP segment with prefilled header.
simon	0:350011bf8be7	143	*
simon	0:350011bf8be7	144	* Called by tcp_write and tcp_enqueue_flags.
simon	0:350011bf8be7	145	*
simon	0:350011bf8be7	146	* @param pcb Protocol control block for the TCP connection.
simon	0:350011bf8be7	147	* @param p pbuf that is used to hold the TCP header.
simon	0:350011bf8be7	148	* @param flags TCP flags for header.
simon	0:350011bf8be7	149	* @param seqno TCP sequence number of this packet
simon	0:350011bf8be7	150	* @param optflags options to include in TCP header
simon	0:350011bf8be7	151	* @return a new tcp_seg pointing to p, or NULL.
simon	0:350011bf8be7	152	* The TCP header is filled in except ackno and wnd.
simon	0:350011bf8be7	153	* p is freed on failure.
simon	0:350011bf8be7	154	*/
simon	0:350011bf8be7	155	static struct tcp_seg *
simon	0:350011bf8be7	156	tcp_create_segment(struct tcp_pcb pcb, struct pbuf p, u8_t flags, u32_t seqno, u8_t optflags)
simon	0:350011bf8be7	157	{
simon	0:350011bf8be7	158	struct tcp_seg *seg;
simon	0:350011bf8be7	159	u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
simon	0:350011bf8be7	160
simon	0:350011bf8be7	161	if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
simon	0:350011bf8be7	162	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no memory.\n"));
simon	0:350011bf8be7	163	pbuf_free(p);
simon	0:350011bf8be7	164	return NULL;
simon	0:350011bf8be7	165	}
simon	0:350011bf8be7	166	seg->flags = optflags;
simon	0:350011bf8be7	167	seg->next = NULL;
simon	0:350011bf8be7	168	seg->p = p;
simon	0:350011bf8be7	169	seg->dataptr = p->payload;
simon	0:350011bf8be7	170	seg->len = p->tot_len - optlen;
simon	0:350011bf8be7	171	#if TCP_OVERSIZE_DBGCHECK
simon	0:350011bf8be7	172	seg->oversize_left = 0;
simon	0:350011bf8be7	173	#endif /* TCP_OVERSIZE_DBGCHECK */
simon	0:350011bf8be7	174	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	175	seg->chksum = 0;
simon	0:350011bf8be7	176	seg->chksum_swapped = 0;
simon	0:350011bf8be7	177	/* check optflags */
simon	0:350011bf8be7	178	LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
simon	0:350011bf8be7	179	(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
simon	0:350011bf8be7	180	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	181
simon	0:350011bf8be7	182	/* build TCP header */
simon	0:350011bf8be7	183	if (pbuf_header(p, TCP_HLEN)) {
simon	0:350011bf8be7	184	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
simon	0:350011bf8be7	185	TCP_STATS_INC(tcp.err);
simon	0:350011bf8be7	186	tcp_seg_free(seg);
simon	0:350011bf8be7	187	return NULL;
simon	0:350011bf8be7	188	}
simon	0:350011bf8be7	189	seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
simon	0:350011bf8be7	190	seg->tcphdr->src = htons(pcb->local_port);
simon	0:350011bf8be7	191	seg->tcphdr->dest = htons(pcb->remote_port);
simon	0:350011bf8be7	192	seg->tcphdr->seqno = htonl(seqno);
simon	0:350011bf8be7	193	/* ackno is set in tcp_output */
simon	0:350011bf8be7	194	TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
simon	0:350011bf8be7	195	/* wnd and chksum are set in tcp_output */
simon	0:350011bf8be7	196	seg->tcphdr->urgp = 0;
simon	0:350011bf8be7	197	return seg;
simon	0:350011bf8be7	198	}
simon	0:350011bf8be7	199
simon	0:350011bf8be7	200	/**
simon	0:350011bf8be7	201	* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
simon	0:350011bf8be7	202	*
simon	0:350011bf8be7	203	* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
simon	0:350011bf8be7	204	* there may be extra bytes available at the end.
simon	0:350011bf8be7	205	*
simon	0:350011bf8be7	206	* @param layer flag to define header size.
simon	0:350011bf8be7	207	* @param length size of the pbuf's payload.
simon	0:350011bf8be7	208	* @param max_length maximum usable size of payload+oversize.
simon	0:350011bf8be7	209	* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
simon	0:350011bf8be7	210	* @param pcb The TCP connection that willo enqueue the pbuf.
simon	0:350011bf8be7	211	* @param apiflags API flags given to tcp_write.
simon	0:350011bf8be7	212	* @param first_seg true when this pbuf will be used in the first enqueued segment.
simon	0:350011bf8be7	213	* @param
simon	0:350011bf8be7	214	*/
simon	0:350011bf8be7	215	#if TCP_OVERSIZE
simon	0:350011bf8be7	216	static struct pbuf *
simon	0:350011bf8be7	217	tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
simon	0:350011bf8be7	218	u16_t oversize, struct tcp_pcb pcb, u8_t apiflags,
simon	0:350011bf8be7	219	u8_t first_seg)
simon	0:350011bf8be7	220	{
simon	0:350011bf8be7	221	struct pbuf *p;
simon	0:350011bf8be7	222	u16_t alloc = length;
simon	0:350011bf8be7	223
simon	0:350011bf8be7	224	#if LWIP_NETIF_TX_SINGLE_PBUF
simon	0:350011bf8be7	225	LWIP_UNUSED_ARG(max_length);
simon	0:350011bf8be7	226	LWIP_UNUSED_ARG(pcb);
simon	0:350011bf8be7	227	LWIP_UNUSED_ARG(apiflags);
simon	0:350011bf8be7	228	LWIP_UNUSED_ARG(first_seg);
simon	0:350011bf8be7	229	/* always create MSS-sized pbufs */
simon	0:350011bf8be7	230	alloc = TCP_MSS;
simon	0:350011bf8be7	231	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
simon	0:350011bf8be7	232	if (length < max_length) {
simon	0:350011bf8be7	233	/* Should we allocate an oversized pbuf, or just the minimum
simon	0:350011bf8be7	234	* length required? If tcp_write is going to be called again
simon	0:350011bf8be7	235	* before this segment is transmitted, we want the oversized
simon	0:350011bf8be7	236	* buffer. If the segment will be transmitted immediately, we can
simon	0:350011bf8be7	237	* save memory by allocating only length. We use a simple
simon	0:350011bf8be7	238	* heuristic based on the following information:
simon	0:350011bf8be7	239	*
simon	0:350011bf8be7	240	* Did the user set TCP_WRITE_FLAG_MORE?
simon	0:350011bf8be7	241	*
simon	0:350011bf8be7	242	* Will the Nagle algorithm defer transmission of this segment?
simon	0:350011bf8be7	243	*/
simon	0:350011bf8be7	244	if ((apiflags & TCP_WRITE_FLAG_MORE) \|\|
simon	0:350011bf8be7	245	(!(pcb->flags & TF_NODELAY) &&
simon	0:350011bf8be7	246	(!first_seg \|\|
simon	0:350011bf8be7	247	pcb->unsent != NULL \|\|
simon	0:350011bf8be7	248	pcb->unacked != NULL))) {
simon	0:350011bf8be7	249	alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
simon	0:350011bf8be7	250	}
simon	0:350011bf8be7	251	}
simon	0:350011bf8be7	252	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
simon	0:350011bf8be7	253	p = pbuf_alloc(layer, alloc, PBUF_RAM);
simon	0:350011bf8be7	254	if (p == NULL) {
simon	0:350011bf8be7	255	return NULL;
simon	0:350011bf8be7	256	}
simon	0:350011bf8be7	257	LWIP_ASSERT("need unchained pbuf", p->next == NULL);
simon	0:350011bf8be7	258	*oversize = p->len - length;
simon	0:350011bf8be7	259	/* trim p->len to the currently used size */
simon	0:350011bf8be7	260	p->len = p->tot_len = length;
simon	0:350011bf8be7	261	return p;
simon	0:350011bf8be7	262	}
simon	0:350011bf8be7	263	#else /* TCP_OVERSIZE */
simon	0:350011bf8be7	264	#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
simon	0:350011bf8be7	265	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	266
simon	0:350011bf8be7	267	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	268	/** Add a checksum of newly added data to the segment */
simon	0:350011bf8be7	269	static void
simon	0:350011bf8be7	270	tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
simon	0:350011bf8be7	271	u8_t *seg_chksum_swapped)
simon	0:350011bf8be7	272	{
simon	0:350011bf8be7	273	u32_t helper;
simon	0:350011bf8be7	274	/* add chksum to old chksum and fold to u16_t */
simon	0:350011bf8be7	275	helper = chksum + *seg_chksum;
simon	0:350011bf8be7	276	chksum = FOLD_U32T(helper);
simon	0:350011bf8be7	277	if ((len & 1) != 0) {
simon	0:350011bf8be7	278	seg_chksum_swapped = 1 - seg_chksum_swapped;
simon	0:350011bf8be7	279	chksum = SWAP_BYTES_IN_WORD(chksum);
simon	0:350011bf8be7	280	}
simon	0:350011bf8be7	281	*seg_chksum = chksum;
simon	0:350011bf8be7	282	}
simon	0:350011bf8be7	283	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	284
simon	0:350011bf8be7	285	/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
simon	0:350011bf8be7	286	*
simon	0:350011bf8be7	287	* @param pcb the tcp pcb to check for
simon	0:350011bf8be7	288	* @param len length of data to send (checked agains snd_buf)
simon	0:350011bf8be7	289	* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
simon	0:350011bf8be7	290	*/
simon	0:350011bf8be7	291	static err_t
simon	0:350011bf8be7	292	tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
simon	0:350011bf8be7	293	{
simon	0:350011bf8be7	294	/* connection is in invalid state for data transmission? */
simon	0:350011bf8be7	295	if ((pcb->state != ESTABLISHED) &&
simon	0:350011bf8be7	296	(pcb->state != CLOSE_WAIT) &&
simon	0:350011bf8be7	297	(pcb->state != SYN_SENT) &&
simon	0:350011bf8be7	298	(pcb->state != SYN_RCVD)) {
simon	0:350011bf8be7	299	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_STATE \| LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
simon	0:350011bf8be7	300	return ERR_CONN;
simon	0:350011bf8be7	301	} else if (len == 0) {
simon	0:350011bf8be7	302	return ERR_OK;
simon	0:350011bf8be7	303	}
simon	0:350011bf8be7	304
simon	0:350011bf8be7	305	/* fail on too much data */
simon	0:350011bf8be7	306	if (len > pcb->snd_buf) {
simon	0:350011bf8be7	307	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
simon	0:350011bf8be7	308	len, pcb->snd_buf));
simon	0:350011bf8be7	309	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	310	return ERR_MEM;
simon	0:350011bf8be7	311	}
simon	0:350011bf8be7	312
simon	0:350011bf8be7	313	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
simon	0:350011bf8be7	314
simon	0:350011bf8be7	315	/* If total number of pbufs on the unsent/unacked queues exceeds the
simon	0:350011bf8be7	316	* configured maximum, return an error */
simon	0:350011bf8be7	317	/* check for configured max queuelen and possible overflow */
simon	0:350011bf8be7	318	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
simon	0:350011bf8be7	319	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
simon	0:350011bf8be7	320	pcb->snd_queuelen, TCP_SND_QUEUELEN));
simon	0:350011bf8be7	321	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	322	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	323	return ERR_MEM;
simon	0:350011bf8be7	324	}
simon	0:350011bf8be7	325	if (pcb->snd_queuelen != 0) {
simon	0:350011bf8be7	326	LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
simon	0:350011bf8be7	327	pcb->unacked != NULL \|\| pcb->unsent != NULL);
simon	0:350011bf8be7	328	} else {
simon	0:350011bf8be7	329	LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
simon	0:350011bf8be7	330	pcb->unacked == NULL && pcb->unsent == NULL);
simon	0:350011bf8be7	331	}
simon	0:350011bf8be7	332	return ERR_OK;
simon	0:350011bf8be7	333	}
simon	0:350011bf8be7	334
simon	0:350011bf8be7	335	/**
simon	0:350011bf8be7	336	* Write data for sending (but does not send it immediately).
simon	0:350011bf8be7	337	*
simon	0:350011bf8be7	338	* It waits in the expectation of more data being sent soon (as
simon	0:350011bf8be7	339	* it can send them more efficiently by combining them together).
simon	0:350011bf8be7	340	* To prompt the system to send data now, call tcp_output() after
simon	0:350011bf8be7	341	* calling tcp_write().
simon	0:350011bf8be7	342	*
simon	0:350011bf8be7	343	* @param pcb Protocol control block for the TCP connection to enqueue data for.
simon	0:350011bf8be7	344	* @param arg Pointer to the data to be enqueued for sending.
simon	0:350011bf8be7	345	* @param len Data length in bytes
simon	0:350011bf8be7	346	* @param apiflags combination of following flags :
simon	0:350011bf8be7	347	* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
simon	0:350011bf8be7	348	* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
simon	0:350011bf8be7	349	* @return ERR_OK if enqueued, another err_t on error
simon	0:350011bf8be7	350	*/
simon	0:350011bf8be7	351	err_t
simon	0:350011bf8be7	352	tcp_write(struct tcp_pcb pcb, const void arg, u16_t len, u8_t apiflags)
simon	0:350011bf8be7	353	{
simon	0:350011bf8be7	354	struct pbuf *concat_p = NULL;
simon	0:350011bf8be7	355	struct tcp_seg last_unsent = NULL, seg = NULL, prev_seg = NULL, queue = NULL;
simon	0:350011bf8be7	356	u16_t pos = 0; /* position in 'arg' data */
simon	0:350011bf8be7	357	u16_t queuelen;
simon	0:350011bf8be7	358	u8_t optlen = 0;
simon	0:350011bf8be7	359	u8_t optflags = 0;
simon	0:350011bf8be7	360	#if TCP_OVERSIZE
simon	0:350011bf8be7	361	u16_t oversize = 0;
simon	0:350011bf8be7	362	u16_t oversize_used = 0;
simon	0:350011bf8be7	363	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	364	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	365	u16_t concat_chksum = 0;
simon	0:350011bf8be7	366	u8_t concat_chksum_swapped = 0;
simon	0:350011bf8be7	367	u16_t concat_chksummed = 0;
simon	0:350011bf8be7	368	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	369	err_t err;
simon	0:350011bf8be7	370
simon	0:350011bf8be7	371	#if LWIP_NETIF_TX_SINGLE_PBUF
simon	0:350011bf8be7	372	/* Always copy to try to create single pbufs for TX */
simon	0:350011bf8be7	373	apiflags \|= TCP_WRITE_FLAG_COPY;
simon	0:350011bf8be7	374	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
simon	0:350011bf8be7	375
simon	0:350011bf8be7	376	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
simon	0:350011bf8be7	377	(void *)pcb, arg, len, (u16_t)apiflags));
simon	0:350011bf8be7	378	LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
simon	0:350011bf8be7	379	arg != NULL, return ERR_ARG;);
simon	0:350011bf8be7	380
simon	0:350011bf8be7	381	err = tcp_write_checks(pcb, len);
simon	0:350011bf8be7	382	if (err != ERR_OK) {
simon	0:350011bf8be7	383	return err;
simon	0:350011bf8be7	384	}
simon	0:350011bf8be7	385	queuelen = pcb->snd_queuelen;
simon	0:350011bf8be7	386
simon	0:350011bf8be7	387	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	388	if ((pcb->flags & TF_TIMESTAMP)) {
simon	0:350011bf8be7	389	optflags = TF_SEG_OPTS_TS;
simon	0:350011bf8be7	390	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
simon	0:350011bf8be7	391	}
simon	0:350011bf8be7	392	#endif /* LWIP_TCP_TIMESTAMPS */
simon	0:350011bf8be7	393
simon	0:350011bf8be7	394
simon	0:350011bf8be7	395	/*
simon	0:350011bf8be7	396	* TCP segmentation is done in three phases with increasing complexity:
simon	0:350011bf8be7	397	*
simon	0:350011bf8be7	398	* 1. Copy data directly into an oversized pbuf.
simon	0:350011bf8be7	399	* 2. Chain a new pbuf to the end of pcb->unsent.
simon	0:350011bf8be7	400	* 3. Create new segments.
simon	0:350011bf8be7	401	*
simon	0:350011bf8be7	402	* We may run out of memory at any point. In that case we must
simon	0:350011bf8be7	403	* return ERR_MEM and not change anything in pcb. Therefore, all
simon	0:350011bf8be7	404	* changes are recorded in local variables and committed at the end
simon	0:350011bf8be7	405	* of the function. Some pcb fields are maintained in local copies:
simon	0:350011bf8be7	406	*
simon	0:350011bf8be7	407	* queuelen = pcb->snd_queuelen
simon	0:350011bf8be7	408	* oversize = pcb->unsent_oversize
simon	0:350011bf8be7	409	*
simon	0:350011bf8be7	410	* These variables are set consistently by the phases:
simon	0:350011bf8be7	411	*
simon	0:350011bf8be7	412	* seg points to the last segment tampered with.
simon	0:350011bf8be7	413	*
simon	0:350011bf8be7	414	* pos records progress as data is segmented.
simon	0:350011bf8be7	415	*/
simon	0:350011bf8be7	416
simon	0:350011bf8be7	417	/* Find the tail of the unsent queue. */
simon	0:350011bf8be7	418	if (pcb->unsent != NULL) {
simon	0:350011bf8be7	419	u16_t space;
simon	0:350011bf8be7	420	u16_t unsent_optlen;
simon	0:350011bf8be7	421
simon	0:350011bf8be7	422	/* @todo: this could be sped up by keeping last_unsent in the pcb */
simon	0:350011bf8be7	423	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
simon	0:350011bf8be7	424	last_unsent = last_unsent->next);
simon	0:350011bf8be7	425
simon	0:350011bf8be7	426	/* Usable space at the end of the last unsent segment */
simon	0:350011bf8be7	427	unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
simon	0:350011bf8be7	428	space = pcb->mss - (last_unsent->len + unsent_optlen);
simon	0:350011bf8be7	429
simon	0:350011bf8be7	430	/*
simon	0:350011bf8be7	431	* Phase 1: Copy data directly into an oversized pbuf.
simon	0:350011bf8be7	432	*
simon	0:350011bf8be7	433	* The number of bytes copied is recorded in the oversize_used
simon	0:350011bf8be7	434	* variable. The actual copying is done at the bottom of the
simon	0:350011bf8be7	435	* function.
simon	0:350011bf8be7	436	*/
simon	0:350011bf8be7	437	#if TCP_OVERSIZE
simon	0:350011bf8be7	438	#if TCP_OVERSIZE_DBGCHECK
simon	0:350011bf8be7	439	/* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
simon	0:350011bf8be7	440	LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
simon	0:350011bf8be7	441	pcb->unsent_oversize == last_unsent->oversize_left);
simon	0:350011bf8be7	442	#endif /* TCP_OVERSIZE_DBGCHECK */
simon	0:350011bf8be7	443	oversize = pcb->unsent_oversize;
simon	0:350011bf8be7	444	if (oversize > 0) {
simon	0:350011bf8be7	445	LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
simon	0:350011bf8be7	446	seg = last_unsent;
simon	0:350011bf8be7	447	oversize_used = oversize < len ? oversize : len;
simon	0:350011bf8be7	448	pos += oversize_used;
simon	0:350011bf8be7	449	oversize -= oversize_used;
simon	0:350011bf8be7	450	space -= oversize_used;
simon	0:350011bf8be7	451	}
simon	0:350011bf8be7	452	/* now we are either finished or oversize is zero */
simon	0:350011bf8be7	453	LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) \|\| (pos == len));
simon	0:350011bf8be7	454	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	455
simon	0:350011bf8be7	456	/*
simon	0:350011bf8be7	457	* Phase 2: Chain a new pbuf to the end of pcb->unsent.
simon	0:350011bf8be7	458	*
simon	0:350011bf8be7	459	* We don't extend segments containing SYN/FIN flags or options
simon	0:350011bf8be7	460	* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
simon	0:350011bf8be7	461	* the end.
simon	0:350011bf8be7	462	*/
simon	0:350011bf8be7	463	if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
simon	0:350011bf8be7	464	u16_t seglen = space < len - pos ? space : len - pos;
simon	0:350011bf8be7	465	seg = last_unsent;
simon	0:350011bf8be7	466
simon	0:350011bf8be7	467	/* Create a pbuf with a copy or reference to seglen bytes. We
simon	0:350011bf8be7	468	* can use PBUF_RAW here since the data appears in the middle of
simon	0:350011bf8be7	469	* a segment. A header will never be prepended. */
simon	0:350011bf8be7	470	if (apiflags & TCP_WRITE_FLAG_COPY) {
simon	0:350011bf8be7	471	/* Data is copied */
simon	0:350011bf8be7	472	if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
simon	0:350011bf8be7	473	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
simon	0:350011bf8be7	474	("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
simon	0:350011bf8be7	475	seglen));
simon	0:350011bf8be7	476	goto memerr;
simon	0:350011bf8be7	477	}
simon	0:350011bf8be7	478	#if TCP_OVERSIZE_DBGCHECK
simon	0:350011bf8be7	479	last_unsent->oversize_left = oversize;
simon	0:350011bf8be7	480	#endif /* TCP_OVERSIZE_DBGCHECK */
simon	0:350011bf8be7	481	TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
simon	0:350011bf8be7	482	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	483	concat_chksummed += seglen;
simon	0:350011bf8be7	484	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	485	} else {
simon	0:350011bf8be7	486	/* Data is not copied */
simon	0:350011bf8be7	487	if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
simon	0:350011bf8be7	488	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
simon	0:350011bf8be7	489	("tcp_write: could not allocate memory for zero-copy pbuf\n"));
simon	0:350011bf8be7	490	goto memerr;
simon	0:350011bf8be7	491	}
simon	0:350011bf8be7	492	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	493	/* calculate the checksum of nocopy-data */
simon	0:350011bf8be7	494	tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
simon	0:350011bf8be7	495	&concat_chksum, &concat_chksum_swapped);
simon	0:350011bf8be7	496	concat_chksummed += seglen;
simon	0:350011bf8be7	497	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	498	/* reference the non-volatile payload data */
simon	0:350011bf8be7	499	concat_p->payload = (u8_t*)arg + pos;
simon	0:350011bf8be7	500	}
simon	0:350011bf8be7	501
simon	0:350011bf8be7	502	pos += seglen;
simon	0:350011bf8be7	503	queuelen += pbuf_clen(concat_p);
simon	0:350011bf8be7	504	}
simon	0:350011bf8be7	505	} else {
simon	0:350011bf8be7	506	#if TCP_OVERSIZE
simon	0:350011bf8be7	507	LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
simon	0:350011bf8be7	508	pcb->unsent_oversize == 0);
simon	0:350011bf8be7	509	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	510	}
simon	0:350011bf8be7	511
simon	0:350011bf8be7	512	/*
simon	0:350011bf8be7	513	* Phase 3: Create new segments.
simon	0:350011bf8be7	514	*
simon	0:350011bf8be7	515	* The new segments are chained together in the local 'queue'
simon	0:350011bf8be7	516	* variable, ready to be appended to pcb->unsent.
simon	0:350011bf8be7	517	*/
simon	0:350011bf8be7	518	while (pos < len) {
simon	0:350011bf8be7	519	struct pbuf *p;
simon	0:350011bf8be7	520	u16_t left = len - pos;
simon	0:350011bf8be7	521	u16_t max_len = pcb->mss - optlen;
simon	0:350011bf8be7	522	u16_t seglen = left > max_len ? max_len : left;
simon	0:350011bf8be7	523	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	524	u16_t chksum = 0;
simon	0:350011bf8be7	525	u8_t chksum_swapped = 0;
simon	0:350011bf8be7	526	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	527
simon	0:350011bf8be7	528	if (apiflags & TCP_WRITE_FLAG_COPY) {
simon	0:350011bf8be7	529	/* If copy is set, memory should be allocated and data copied
simon	0:350011bf8be7	530	* into pbuf */
simon	0:350011bf8be7	531	if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
simon	0:350011bf8be7	532	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
simon	0:350011bf8be7	533	goto memerr;
simon	0:350011bf8be7	534	}
simon	0:350011bf8be7	535	LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
simon	0:350011bf8be7	536	(p->len >= seglen));
simon	0:350011bf8be7	537	TCP_DATA_COPY2((char )p->payload + optlen, (u8_t)arg + pos, seglen, &chksum, &chksum_swapped);
simon	0:350011bf8be7	538	} else {
simon	0:350011bf8be7	539	/* Copy is not set: First allocate a pbuf for holding the data.
simon	0:350011bf8be7	540	* Since the referenced data is available at least until it is
simon	0:350011bf8be7	541	* sent out on the link (as it has to be ACKed by the remote
simon	0:350011bf8be7	542	* party) we can safely use PBUF_ROM instead of PBUF_REF here.
simon	0:350011bf8be7	543	*/
simon	0:350011bf8be7	544	struct pbuf *p2;
simon	0:350011bf8be7	545	#if TCP_OVERSIZE
simon	0:350011bf8be7	546	LWIP_ASSERT("oversize == 0", oversize == 0);
simon	0:350011bf8be7	547	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	548	if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
simon	0:350011bf8be7	549	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
simon	0:350011bf8be7	550	goto memerr;
simon	0:350011bf8be7	551	}
simon	0:350011bf8be7	552	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	553	/* calculate the checksum of nocopy-data */
simon	0:350011bf8be7	554	chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
simon	0:350011bf8be7	555	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	556	/* reference the non-volatile payload data */
simon	0:350011bf8be7	557	p2->payload = (u8_t*)arg + pos;
simon	0:350011bf8be7	558
simon	0:350011bf8be7	559	/* Second, allocate a pbuf for the headers. */
simon	0:350011bf8be7	560	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
simon	0:350011bf8be7	561	/* If allocation fails, we have to deallocate the data pbuf as
simon	0:350011bf8be7	562	* well. */
simon	0:350011bf8be7	563	pbuf_free(p2);
simon	0:350011bf8be7	564	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for header pbuf\n"));
simon	0:350011bf8be7	565	goto memerr;
simon	0:350011bf8be7	566	}
simon	0:350011bf8be7	567	/* Concatenate the headers and data pbufs together. */
simon	0:350011bf8be7	568	pbuf_cat(p/header/, p2/data/);
simon	0:350011bf8be7	569	}
simon	0:350011bf8be7	570
simon	0:350011bf8be7	571	queuelen += pbuf_clen(p);
simon	0:350011bf8be7	572
simon	0:350011bf8be7	573	/* Now that there are more segments queued, we check again if the
simon	0:350011bf8be7	574	* length of the queue exceeds the configured maximum or
simon	0:350011bf8be7	575	* overflows. */
simon	0:350011bf8be7	576	if ((queuelen > TCP_SND_QUEUELEN) \|\| (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
simon	0:350011bf8be7	577	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
simon	0:350011bf8be7	578	pbuf_free(p);
simon	0:350011bf8be7	579	goto memerr;
simon	0:350011bf8be7	580	}
simon	0:350011bf8be7	581
simon	0:350011bf8be7	582	if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
simon	0:350011bf8be7	583	goto memerr;
simon	0:350011bf8be7	584	}
simon	0:350011bf8be7	585	#if TCP_OVERSIZE_DBGCHECK
simon	0:350011bf8be7	586	seg->oversize_left = oversize;
simon	0:350011bf8be7	587	#endif /* TCP_OVERSIZE_DBGCHECK */
simon	0:350011bf8be7	588	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	589	seg->chksum = chksum;
simon	0:350011bf8be7	590	seg->chksum_swapped = chksum_swapped;
simon	0:350011bf8be7	591	seg->flags \|= TF_SEG_DATA_CHECKSUMMED;
simon	0:350011bf8be7	592	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	593	/* Fix dataptr for the nocopy case */
simon	0:350011bf8be7	594	if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
simon	0:350011bf8be7	595	seg->dataptr = (u8_t*)arg + pos;
simon	0:350011bf8be7	596	}
simon	0:350011bf8be7	597
simon	0:350011bf8be7	598	/* first segment of to-be-queued data? */
simon	0:350011bf8be7	599	if (queue == NULL) {
simon	0:350011bf8be7	600	queue = seg;
simon	0:350011bf8be7	601	} else {
simon	0:350011bf8be7	602	/* Attach the segment to the end of the queued segments */
simon	0:350011bf8be7	603	LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
simon	0:350011bf8be7	604	prev_seg->next = seg;
simon	0:350011bf8be7	605	}
simon	0:350011bf8be7	606	/* remember last segment of to-be-queued data for next iteration */
simon	0:350011bf8be7	607	prev_seg = seg;
simon	0:350011bf8be7	608
simon	0:350011bf8be7	609	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
simon	0:350011bf8be7	610	ntohl(seg->tcphdr->seqno),
simon	0:350011bf8be7	611	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
simon	0:350011bf8be7	612
simon	0:350011bf8be7	613	pos += seglen;
simon	0:350011bf8be7	614	}
simon	0:350011bf8be7	615
simon	0:350011bf8be7	616	/*
simon	0:350011bf8be7	617	* All three segmentation phases were successful. We can commit the
simon	0:350011bf8be7	618	* transaction.
simon	0:350011bf8be7	619	*/
simon	0:350011bf8be7	620
simon	0:350011bf8be7	621	/*
simon	0:350011bf8be7	622	* Phase 1: If data has been added to the preallocated tail of
simon	0:350011bf8be7	623	* last_unsent, we update the length fields of the pbuf chain.
simon	0:350011bf8be7	624	*/
simon	0:350011bf8be7	625	#if TCP_OVERSIZE
simon	0:350011bf8be7	626	if (oversize_used > 0) {
simon	0:350011bf8be7	627	struct pbuf *p;
simon	0:350011bf8be7	628	/* Bump tot_len of whole chain, len of tail */
simon	0:350011bf8be7	629	for (p = last_unsent->p; p; p = p->next) {
simon	0:350011bf8be7	630	p->tot_len += oversize_used;
simon	0:350011bf8be7	631	if (p->next == NULL) {
simon	0:350011bf8be7	632	TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
simon	0:350011bf8be7	633	p->len += oversize_used;
simon	0:350011bf8be7	634	}
simon	0:350011bf8be7	635	}
simon	0:350011bf8be7	636	last_unsent->len += oversize_used;
simon	0:350011bf8be7	637	#if TCP_OVERSIZE_DBGCHECK
simon	0:350011bf8be7	638	last_unsent->oversize_left -= oversize_used;
simon	0:350011bf8be7	639	#endif /* TCP_OVERSIZE_DBGCHECK */
simon	0:350011bf8be7	640	}
simon	0:350011bf8be7	641	pcb->unsent_oversize = oversize;
simon	0:350011bf8be7	642	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	643
simon	0:350011bf8be7	644	/*
simon	0:350011bf8be7	645	* Phase 2: concat_p can be concatenated onto last_unsent->p
simon	0:350011bf8be7	646	*/
simon	0:350011bf8be7	647	if (concat_p != NULL) {
simon	0:350011bf8be7	648	LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
simon	0:350011bf8be7	649	(last_unsent != NULL));
simon	0:350011bf8be7	650	pbuf_cat(last_unsent->p, concat_p);
simon	0:350011bf8be7	651	last_unsent->len += concat_p->tot_len;
simon	0:350011bf8be7	652	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	653	if (concat_chksummed) {
simon	0:350011bf8be7	654	tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
simon	0:350011bf8be7	655	&last_unsent->chksum_swapped);
simon	0:350011bf8be7	656	last_unsent->flags \|= TF_SEG_DATA_CHECKSUMMED;
simon	0:350011bf8be7	657	}
simon	0:350011bf8be7	658	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	659	}
simon	0:350011bf8be7	660
simon	0:350011bf8be7	661	/*
simon	0:350011bf8be7	662	* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
simon	0:350011bf8be7	663	* is harmless
simon	0:350011bf8be7	664	*/
simon	0:350011bf8be7	665	if (last_unsent == NULL) {
simon	0:350011bf8be7	666	pcb->unsent = queue;
simon	0:350011bf8be7	667	} else {
simon	0:350011bf8be7	668	last_unsent->next = queue;
simon	0:350011bf8be7	669	}
simon	0:350011bf8be7	670
simon	0:350011bf8be7	671	/*
simon	0:350011bf8be7	672	* Finally update the pcb state.
simon	0:350011bf8be7	673	*/
simon	0:350011bf8be7	674	pcb->snd_lbb += len;
simon	0:350011bf8be7	675	pcb->snd_buf -= len;
simon	0:350011bf8be7	676	pcb->snd_queuelen = queuelen;
simon	0:350011bf8be7	677
simon	0:350011bf8be7	678	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
simon	0:350011bf8be7	679	pcb->snd_queuelen));
simon	0:350011bf8be7	680	if (pcb->snd_queuelen != 0) {
simon	0:350011bf8be7	681	LWIP_ASSERT("tcp_write: valid queue length",
simon	0:350011bf8be7	682	pcb->unacked != NULL \|\| pcb->unsent != NULL);
simon	0:350011bf8be7	683	}
simon	0:350011bf8be7	684
simon	0:350011bf8be7	685	/* Set the PSH flag in the last segment that we enqueued. */
simon	0:350011bf8be7	686	if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
simon	0:350011bf8be7	687	TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
simon	0:350011bf8be7	688	}
simon	0:350011bf8be7	689
simon	0:350011bf8be7	690	return ERR_OK;
simon	0:350011bf8be7	691	memerr:
simon	0:350011bf8be7	692	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	693	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	694
simon	0:350011bf8be7	695	if (concat_p != NULL) {
simon	0:350011bf8be7	696	pbuf_free(concat_p);
simon	0:350011bf8be7	697	}
simon	0:350011bf8be7	698	if (queue != NULL) {
simon	0:350011bf8be7	699	tcp_segs_free(queue);
simon	0:350011bf8be7	700	}
simon	0:350011bf8be7	701	if (pcb->snd_queuelen != 0) {
simon	0:350011bf8be7	702	LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL \|\|
simon	0:350011bf8be7	703	pcb->unsent != NULL);
simon	0:350011bf8be7	704	}
simon	0:350011bf8be7	705	LWIP_DEBUGF(TCP_QLEN_DEBUG \| LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
simon	0:350011bf8be7	706	return ERR_MEM;
simon	0:350011bf8be7	707	}
simon	0:350011bf8be7	708
simon	0:350011bf8be7	709	/**
simon	0:350011bf8be7	710	* Enqueue TCP options for transmission.
simon	0:350011bf8be7	711	*
simon	0:350011bf8be7	712	* Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
simon	0:350011bf8be7	713	*
simon	0:350011bf8be7	714	* @param pcb Protocol control block for the TCP connection.
simon	0:350011bf8be7	715	* @param flags TCP header flags to set in the outgoing segment.
simon	0:350011bf8be7	716	* @param optdata pointer to TCP options, or NULL.
simon	0:350011bf8be7	717	* @param optlen length of TCP options in bytes.
simon	0:350011bf8be7	718	*/
simon	0:350011bf8be7	719	err_t
simon	0:350011bf8be7	720	tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
simon	0:350011bf8be7	721	{
simon	0:350011bf8be7	722	struct pbuf *p;
simon	0:350011bf8be7	723	struct tcp_seg *seg;
simon	0:350011bf8be7	724	u8_t optflags = 0;
simon	0:350011bf8be7	725	u8_t optlen = 0;
simon	0:350011bf8be7	726
simon	0:350011bf8be7	727	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
simon	0:350011bf8be7	728
simon	0:350011bf8be7	729	LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
simon	0:350011bf8be7	730	(flags & (TCP_SYN \| TCP_FIN)) != 0);
simon	0:350011bf8be7	731
simon	0:350011bf8be7	732	/* check for configured max queuelen and possible overflow */
simon	0:350011bf8be7	733	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
simon	0:350011bf8be7	734	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
simon	0:350011bf8be7	735	pcb->snd_queuelen, TCP_SND_QUEUELEN));
simon	0:350011bf8be7	736	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	737	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	738	return ERR_MEM;
simon	0:350011bf8be7	739	}
simon	0:350011bf8be7	740
simon	0:350011bf8be7	741	if (flags & TCP_SYN) {
simon	0:350011bf8be7	742	optflags = TF_SEG_OPTS_MSS;
simon	0:350011bf8be7	743	}
simon	0:350011bf8be7	744	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	745	if ((pcb->flags & TF_TIMESTAMP)) {
simon	0:350011bf8be7	746	optflags \|= TF_SEG_OPTS_TS;
simon	0:350011bf8be7	747	}
simon	0:350011bf8be7	748	#endif /* LWIP_TCP_TIMESTAMPS */
simon	0:350011bf8be7	749	optlen = LWIP_TCP_OPT_LENGTH(optflags);
simon	0:350011bf8be7	750
simon	0:350011bf8be7	751	/* tcp_enqueue_flags is always called with either SYN or FIN in flags.
simon	0:350011bf8be7	752	* We need one available snd_buf byte to do that.
simon	0:350011bf8be7	753	* This means we can't send FIN while snd_buf==0. A better fix would be to
simon	0:350011bf8be7	754	* not include SYN and FIN sequence numbers in the snd_buf count. */
simon	0:350011bf8be7	755	if (pcb->snd_buf == 0) {
simon	0:350011bf8be7	756	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: no send buffer available\n"));
simon	0:350011bf8be7	757	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	758	return ERR_MEM;
simon	0:350011bf8be7	759	}
simon	0:350011bf8be7	760
simon	0:350011bf8be7	761	/* Allocate pbuf with room for TCP header + options */
simon	0:350011bf8be7	762	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
simon	0:350011bf8be7	763	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	764	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	765	return ERR_MEM;
simon	0:350011bf8be7	766	}
simon	0:350011bf8be7	767	LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
simon	0:350011bf8be7	768	(p->len >= optlen));
simon	0:350011bf8be7	769
simon	0:350011bf8be7	770	/* Allocate memory for tcp_seg, and fill in fields. */
simon	0:350011bf8be7	771	if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
simon	0:350011bf8be7	772	pcb->flags \|= TF_NAGLEMEMERR;
simon	0:350011bf8be7	773	TCP_STATS_INC(tcp.memerr);
simon	0:350011bf8be7	774	return ERR_MEM;
simon	0:350011bf8be7	775	}
simon	0:350011bf8be7	776	LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
simon	0:350011bf8be7	777
simon	0:350011bf8be7	778	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE,
simon	0:350011bf8be7	779	("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
simon	0:350011bf8be7	780	ntohl(seg->tcphdr->seqno),
simon	0:350011bf8be7	781	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
simon	0:350011bf8be7	782	(u16_t)flags));
simon	0:350011bf8be7	783
simon	0:350011bf8be7	784	/* Now append seg to pcb->unsent queue */
simon	0:350011bf8be7	785	if (pcb->unsent == NULL) {
simon	0:350011bf8be7	786	pcb->unsent = seg;
simon	0:350011bf8be7	787	} else {
simon	0:350011bf8be7	788	struct tcp_seg *useg;
simon	0:350011bf8be7	789	for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
simon	0:350011bf8be7	790	useg->next = seg;
simon	0:350011bf8be7	791	}
simon	0:350011bf8be7	792	#if TCP_OVERSIZE
simon	0:350011bf8be7	793	/* The new unsent tail has no space */
simon	0:350011bf8be7	794	pcb->unsent_oversize = 0;
simon	0:350011bf8be7	795	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	796
simon	0:350011bf8be7	797	/* SYN and FIN bump the sequence number */
simon	0:350011bf8be7	798	if ((flags & TCP_SYN) \|\| (flags & TCP_FIN)) {
simon	0:350011bf8be7	799	pcb->snd_lbb++;
simon	0:350011bf8be7	800	/* optlen does not influence snd_buf */
simon	0:350011bf8be7	801	pcb->snd_buf--;
simon	0:350011bf8be7	802	}
simon	0:350011bf8be7	803	if (flags & TCP_FIN) {
simon	0:350011bf8be7	804	pcb->flags \|= TF_FIN;
simon	0:350011bf8be7	805	}
simon	0:350011bf8be7	806
simon	0:350011bf8be7	807	/* update number of segments on the queues */
simon	0:350011bf8be7	808	pcb->snd_queuelen += pbuf_clen(seg->p);
simon	0:350011bf8be7	809	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
simon	0:350011bf8be7	810	if (pcb->snd_queuelen != 0) {
simon	0:350011bf8be7	811	LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
simon	0:350011bf8be7	812	pcb->unacked != NULL \|\| pcb->unsent != NULL);
simon	0:350011bf8be7	813	}
simon	0:350011bf8be7	814
simon	0:350011bf8be7	815	return ERR_OK;
simon	0:350011bf8be7	816	}
simon	0:350011bf8be7	817
simon	0:350011bf8be7	818
simon	0:350011bf8be7	819	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	820	/* Build a timestamp option (12 bytes long) at the specified options pointer)
simon	0:350011bf8be7	821	*
simon	0:350011bf8be7	822	* @param pcb tcp_pcb
simon	0:350011bf8be7	823	* @param opts option pointer where to store the timestamp option
simon	0:350011bf8be7	824	*/
simon	0:350011bf8be7	825	static void
simon	0:350011bf8be7	826	tcp_build_timestamp_option(struct tcp_pcb pcb, u32_t opts)
simon	0:350011bf8be7	827	{
simon	0:350011bf8be7	828	/* Pad with two NOP options to make everything nicely aligned */
simon	0:350011bf8be7	829	opts[0] = PP_HTONL(0x0101080A);
simon	0:350011bf8be7	830	opts[1] = htonl(sys_now());
simon	0:350011bf8be7	831	opts[2] = htonl(pcb->ts_recent);
simon	0:350011bf8be7	832	}
simon	0:350011bf8be7	833	#endif
simon	0:350011bf8be7	834
simon	0:350011bf8be7	835	/** Send an ACK without data.
simon	0:350011bf8be7	836	*
simon	0:350011bf8be7	837	* @param pcb Protocol control block for the TCP connection to send the ACK
simon	0:350011bf8be7	838	*/
simon	0:350011bf8be7	839	err_t
simon	0:350011bf8be7	840	tcp_send_empty_ack(struct tcp_pcb *pcb)
simon	0:350011bf8be7	841	{
simon	0:350011bf8be7	842	struct pbuf *p;
simon	0:350011bf8be7	843	struct tcp_hdr *tcphdr;
simon	0:350011bf8be7	844	u8_t optlen = 0;
simon	0:350011bf8be7	845
simon	0:350011bf8be7	846	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	847	if (pcb->flags & TF_TIMESTAMP) {
simon	0:350011bf8be7	848	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
simon	0:350011bf8be7	849	}
simon	0:350011bf8be7	850	#endif
simon	0:350011bf8be7	851
simon	0:350011bf8be7	852	p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
simon	0:350011bf8be7	853	if (p == NULL) {
simon	0:350011bf8be7	854	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
simon	0:350011bf8be7	855	return ERR_BUF;
simon	0:350011bf8be7	856	}
simon	0:350011bf8be7	857	tcphdr = (struct tcp_hdr *)p->payload;
simon	0:350011bf8be7	858	LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
simon	0:350011bf8be7	859	("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
simon	0:350011bf8be7	860	/* remove ACK flags from the PCB, as we send an empty ACK now */
simon	0:350011bf8be7	861	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
simon	0:350011bf8be7	862
simon	0:350011bf8be7	863	/* NB. MSS option is only sent on SYNs, so ignore it here */
simon	0:350011bf8be7	864	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	865	pcb->ts_lastacksent = pcb->rcv_nxt;
simon	0:350011bf8be7	866
simon	0:350011bf8be7	867	if (pcb->flags & TF_TIMESTAMP) {
simon	0:350011bf8be7	868	tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
simon	0:350011bf8be7	869	}
simon	0:350011bf8be7	870	#endif
simon	0:350011bf8be7	871
simon	0:350011bf8be7	872	#if CHECKSUM_GEN_TCP
simon	0:350011bf8be7	873	tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
simon	0:350011bf8be7	874	IP_PROTO_TCP, p->tot_len);
simon	0:350011bf8be7	875	#endif
simon	0:350011bf8be7	876	#if LWIP_NETIF_HWADDRHINT
simon	0:350011bf8be7	877	ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
simon	0:350011bf8be7	878	IP_PROTO_TCP, &(pcb->addr_hint));
simon	0:350011bf8be7	879	#else /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	880	ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
simon	0:350011bf8be7	881	IP_PROTO_TCP);
simon	0:350011bf8be7	882	#endif /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	883	pbuf_free(p);
simon	0:350011bf8be7	884
simon	0:350011bf8be7	885	return ERR_OK;
simon	0:350011bf8be7	886	}
simon	0:350011bf8be7	887
simon	0:350011bf8be7	888	/**
simon	0:350011bf8be7	889	* Find out what we can send and send it
simon	0:350011bf8be7	890	*
simon	0:350011bf8be7	891	* @param pcb Protocol control block for the TCP connection to send data
simon	0:350011bf8be7	892	* @return ERR_OK if data has been sent or nothing to send
simon	0:350011bf8be7	893	* another err_t on error
simon	0:350011bf8be7	894	*/
simon	0:350011bf8be7	895	err_t
simon	0:350011bf8be7	896	tcp_output(struct tcp_pcb *pcb)
simon	0:350011bf8be7	897	{
simon	0:350011bf8be7	898	struct tcp_seg seg, useg;
simon	0:350011bf8be7	899	u32_t wnd, snd_nxt;
simon	0:350011bf8be7	900	#if TCP_CWND_DEBUG
simon	0:350011bf8be7	901	s16_t i = 0;
simon	0:350011bf8be7	902	#endif /* TCP_CWND_DEBUG */
simon	0:350011bf8be7	903
simon	0:350011bf8be7	904	/* First, check if we are invoked by the TCP input processing
simon	0:350011bf8be7	905	code. If so, we do not output anything. Instead, we rely on the
simon	0:350011bf8be7	906	input processing code to call us when input processing is done
simon	0:350011bf8be7	907	with. */
simon	0:350011bf8be7	908	if (tcp_input_pcb == pcb) {
simon	0:350011bf8be7	909	return ERR_OK;
simon	0:350011bf8be7	910	}
simon	0:350011bf8be7	911
simon	0:350011bf8be7	912	wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
simon	0:350011bf8be7	913
simon	0:350011bf8be7	914	seg = pcb->unsent;
simon	0:350011bf8be7	915
simon	0:350011bf8be7	916	/* If the TF_ACK_NOW flag is set and no data will be sent (either
simon	0:350011bf8be7	917	* because the ->unsent queue is empty or because the window does
simon	0:350011bf8be7	918	* not allow it), construct an empty ACK segment and send it.
simon	0:350011bf8be7	919	*
simon	0:350011bf8be7	920	* If data is to be sent, we will just piggyback the ACK (see below).
simon	0:350011bf8be7	921	*/
simon	0:350011bf8be7	922	if (pcb->flags & TF_ACK_NOW &&
simon	0:350011bf8be7	923	(seg == NULL \|\|
simon	0:350011bf8be7	924	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
simon	0:350011bf8be7	925	return tcp_send_empty_ack(pcb);
simon	0:350011bf8be7	926	}
simon	0:350011bf8be7	927
simon	0:350011bf8be7	928	/* useg should point to last segment on unacked queue */
simon	0:350011bf8be7	929	useg = pcb->unacked;
simon	0:350011bf8be7	930	if (useg != NULL) {
simon	0:350011bf8be7	931	for (; useg->next != NULL; useg = useg->next);
simon	0:350011bf8be7	932	}
simon	0:350011bf8be7	933
simon	0:350011bf8be7	934	#if TCP_OUTPUT_DEBUG
simon	0:350011bf8be7	935	if (seg == NULL) {
simon	0:350011bf8be7	936	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
simon	0:350011bf8be7	937	(void*)pcb->unsent));
simon	0:350011bf8be7	938	}
simon	0:350011bf8be7	939	#endif /* TCP_OUTPUT_DEBUG */
simon	0:350011bf8be7	940	#if TCP_CWND_DEBUG
simon	0:350011bf8be7	941	if (seg == NULL) {
simon	0:350011bf8be7	942	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
simon	0:350011bf8be7	943	", cwnd %"U16_F", wnd %"U32_F
simon	0:350011bf8be7	944	", seg == NULL, ack %"U32_F"\n",
simon	0:350011bf8be7	945	pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
simon	0:350011bf8be7	946	} else {
simon	0:350011bf8be7	947	LWIP_DEBUGF(TCP_CWND_DEBUG,
simon	0:350011bf8be7	948	("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
simon	0:350011bf8be7	949	", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
simon	0:350011bf8be7	950	pcb->snd_wnd, pcb->cwnd, wnd,
simon	0:350011bf8be7	951	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
simon	0:350011bf8be7	952	ntohl(seg->tcphdr->seqno), pcb->lastack));
simon	0:350011bf8be7	953	}
simon	0:350011bf8be7	954	#endif /* TCP_CWND_DEBUG */
simon	0:350011bf8be7	955	/* data available and window allows it to be sent? */
simon	0:350011bf8be7	956	while (seg != NULL &&
simon	0:350011bf8be7	957	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
simon	0:350011bf8be7	958	LWIP_ASSERT("RST not expected here!",
simon	0:350011bf8be7	959	(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
simon	0:350011bf8be7	960	/* Stop sending if the nagle algorithm would prevent it
simon	0:350011bf8be7	961	* Don't stop:
simon	0:350011bf8be7	962	* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
simon	0:350011bf8be7	963	* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
simon	0:350011bf8be7	964	* either seg->next != NULL or pcb->unacked == NULL;
simon	0:350011bf8be7	965	* RST is no sent using tcp_write/tcp_output.
simon	0:350011bf8be7	966	*/
simon	0:350011bf8be7	967	if((tcp_do_output_nagle(pcb) == 0) &&
simon	0:350011bf8be7	968	((pcb->flags & (TF_NAGLEMEMERR \| TF_FIN)) == 0)){
simon	0:350011bf8be7	969	break;
simon	0:350011bf8be7	970	}
simon	0:350011bf8be7	971	#if TCP_CWND_DEBUG
simon	0:350011bf8be7	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",
simon	0:350011bf8be7	973	pcb->snd_wnd, pcb->cwnd, wnd,
simon	0:350011bf8be7	974	ntohl(seg->tcphdr->seqno) + seg->len -
simon	0:350011bf8be7	975	pcb->lastack,
simon	0:350011bf8be7	976	ntohl(seg->tcphdr->seqno), pcb->lastack, i));
simon	0:350011bf8be7	977	++i;
simon	0:350011bf8be7	978	#endif /* TCP_CWND_DEBUG */
simon	0:350011bf8be7	979
simon	0:350011bf8be7	980	pcb->unsent = seg->next;
simon	0:350011bf8be7	981
simon	0:350011bf8be7	982	if (pcb->state != SYN_SENT) {
simon	0:350011bf8be7	983	TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
simon	0:350011bf8be7	984	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
simon	0:350011bf8be7	985	}
simon	0:350011bf8be7	986
simon	0:350011bf8be7	987	tcp_output_segment(seg, pcb);
simon	0:350011bf8be7	988
simon	0:350011bf8be7	989	snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
simon	0:350011bf8be7	990
simon	0:350011bf8be7	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
simon	0:350011bf8be7	992	pcb->snd_nxt, ntohl(seg->tcphdr->seqno), TCP_TCPLEN(seg), snd_nxt));
simon	0:350011bf8be7	993
simon	0:350011bf8be7	994	if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
simon	0:350011bf8be7	995	pcb->snd_nxt = snd_nxt;
simon	0:350011bf8be7	996	}
simon	0:350011bf8be7	997	/* put segment on unacknowledged list if length > 0 */
simon	0:350011bf8be7	998	if (TCP_TCPLEN(seg) > 0) {
simon	0:350011bf8be7	999	seg->next = NULL;
simon	0:350011bf8be7	1000	/* unacked list is empty? */
simon	0:350011bf8be7	1001	if (pcb->unacked == NULL) {
simon	0:350011bf8be7	1002	pcb->unacked = seg;
simon	0:350011bf8be7	1003	useg = seg;
simon	0:350011bf8be7	1004	/* unacked list is not empty? */
simon	0:350011bf8be7	1005	} else {
simon	0:350011bf8be7	1006	/* In the case of fast retransmit, the packet should not go to the tail
simon	0:350011bf8be7	1007	* of the unacked queue, but rather somewhere before it. We need to check for
simon	0:350011bf8be7	1008	* this case. -STJ Jul 27, 2004 */
simon	0:350011bf8be7	1009	if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
simon	0:350011bf8be7	1010	/* add segment to before tail of unacked list, keeping the list sorted */
simon	0:350011bf8be7	1011	struct tcp_seg **cur_seg = &(pcb->unacked);
simon	0:350011bf8be7	1012	while (*cur_seg &&
simon	0:350011bf8be7	1013	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
simon	0:350011bf8be7	1014	cur_seg = &((*cur_seg)->next );
simon	0:350011bf8be7	1015	}
simon	0:350011bf8be7	1016	seg->next = (*cur_seg);
simon	0:350011bf8be7	1017	(*cur_seg) = seg;
simon	0:350011bf8be7	1018	} else {
simon	0:350011bf8be7	1019	/* add segment to tail of unacked list */
simon	0:350011bf8be7	1020	useg->next = seg;
simon	0:350011bf8be7	1021	useg = useg->next;
simon	0:350011bf8be7	1022	}
simon	0:350011bf8be7	1023	}
simon	0:350011bf8be7	1024	/* do not queue empty segments on the unacked list */
simon	0:350011bf8be7	1025	} else {
simon	0:350011bf8be7	1026	tcp_seg_free(seg);
simon	0:350011bf8be7	1027	}
simon	0:350011bf8be7	1028	seg = pcb->unsent;
simon	0:350011bf8be7	1029	}
simon	0:350011bf8be7	1030	#if TCP_OVERSIZE
simon	0:350011bf8be7	1031	if (pcb->unsent == NULL) {
simon	0:350011bf8be7	1032	/* last unsent has been removed, reset unsent_oversize */
simon	0:350011bf8be7	1033	pcb->unsent_oversize = 0;
simon	0:350011bf8be7	1034	}
simon	0:350011bf8be7	1035	#endif /* TCP_OVERSIZE */
simon	0:350011bf8be7	1036
simon	0:350011bf8be7	1037	if (seg != NULL && pcb->persist_backoff == 0 &&
simon	0:350011bf8be7	1038	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
simon	0:350011bf8be7	1039	/* prepare for persist timer */
simon	0:350011bf8be7	1040	pcb->persist_cnt = 0;
simon	0:350011bf8be7	1041	pcb->persist_backoff = 1;
simon	0:350011bf8be7	1042	}
simon	0:350011bf8be7	1043
simon	0:350011bf8be7	1044	pcb->flags &= ~TF_NAGLEMEMERR;
simon	0:350011bf8be7	1045	return ERR_OK;
simon	0:350011bf8be7	1046	}
simon	0:350011bf8be7	1047
simon	0:350011bf8be7	1048	/**
simon	0:350011bf8be7	1049	* Called by tcp_output() to actually send a TCP segment over IP.
simon	0:350011bf8be7	1050	*
simon	0:350011bf8be7	1051	* @param seg the tcp_seg to send
simon	0:350011bf8be7	1052	* @param pcb the tcp_pcb for the TCP connection used to send the segment
simon	0:350011bf8be7	1053	*/
simon	0:350011bf8be7	1054	static void
simon	0:350011bf8be7	1055	tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb)
simon	0:350011bf8be7	1056	{
simon	0:350011bf8be7	1057	u16_t len;
simon	0:350011bf8be7	1058	struct netif *netif;
simon	0:350011bf8be7	1059	u32_t *opts;
simon	0:350011bf8be7	1060
simon	0:350011bf8be7	1061	/** @bug Exclude retransmitted segments from this count. */
simon	0:350011bf8be7	1062	snmp_inc_tcpoutsegs();
simon	0:350011bf8be7	1063
simon	0:350011bf8be7	1064	/* The TCP header has already been constructed, but the ackno and
simon	0:350011bf8be7	1065	wnd fields remain. */
simon	0:350011bf8be7	1066	seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
simon	0:350011bf8be7	1067
simon	0:350011bf8be7	1068	/* advertise our receive window size in this TCP segment */
simon	0:350011bf8be7	1069	seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
simon	0:350011bf8be7	1070
simon	0:350011bf8be7	1071	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
simon	0:350011bf8be7	1072
simon	0:350011bf8be7	1073	/* Add any requested options. NB MSS option is only set on SYN
simon	0:350011bf8be7	1074	packets, so ignore it here */
simon	0:350011bf8be7	1075	LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)(seg->tcphdr + 1) % 4) == 0);
simon	0:350011bf8be7	1076	opts = (u32_t )(void )(seg->tcphdr + 1);
simon	0:350011bf8be7	1077	if (seg->flags & TF_SEG_OPTS_MSS) {
simon	0:350011bf8be7	1078	TCP_BUILD_MSS_OPTION(*opts);
simon	0:350011bf8be7	1079	opts += 1;
simon	0:350011bf8be7	1080	}
simon	0:350011bf8be7	1081	#if LWIP_TCP_TIMESTAMPS
simon	0:350011bf8be7	1082	pcb->ts_lastacksent = pcb->rcv_nxt;
simon	0:350011bf8be7	1083
simon	0:350011bf8be7	1084	if (seg->flags & TF_SEG_OPTS_TS) {
simon	0:350011bf8be7	1085	tcp_build_timestamp_option(pcb, opts);
simon	0:350011bf8be7	1086	opts += 3;
simon	0:350011bf8be7	1087	}
simon	0:350011bf8be7	1088	#endif
simon	0:350011bf8be7	1089
simon	0:350011bf8be7	1090	/* If we don't have a local IP address, we get one by
simon	0:350011bf8be7	1091	calling ip_route(). */
simon	0:350011bf8be7	1092	if (ip_addr_isany(&(pcb->local_ip))) {
simon	0:350011bf8be7	1093	netif = ip_route(&(pcb->remote_ip));
simon	0:350011bf8be7	1094	if (netif == NULL) {
simon	0:350011bf8be7	1095	return;
simon	0:350011bf8be7	1096	}
simon	0:350011bf8be7	1097	ip_addr_copy(pcb->local_ip, netif->ip_addr);
simon	0:350011bf8be7	1098	}
simon	0:350011bf8be7	1099
simon	0:350011bf8be7	1100	/* Set retransmission timer running if it is not currently enabled */
simon	0:350011bf8be7	1101	if(pcb->rtime == -1) {
simon	0:350011bf8be7	1102	pcb->rtime = 0;
simon	0:350011bf8be7	1103	}
simon	0:350011bf8be7	1104
simon	0:350011bf8be7	1105	if (pcb->rttest == 0) {
simon	0:350011bf8be7	1106	pcb->rttest = tcp_ticks;
simon	0:350011bf8be7	1107	pcb->rtseq = ntohl(seg->tcphdr->seqno);
simon	0:350011bf8be7	1108
simon	0:350011bf8be7	1109	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
simon	0:350011bf8be7	1110	}
simon	0:350011bf8be7	1111	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
simon	0:350011bf8be7	1112	htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
simon	0:350011bf8be7	1113	seg->len));
simon	0:350011bf8be7	1114
simon	0:350011bf8be7	1115	len = (u16_t)((u8_t )seg->tcphdr - (u8_t )seg->p->payload);
simon	0:350011bf8be7	1116
simon	0:350011bf8be7	1117	seg->p->len -= len;
simon	0:350011bf8be7	1118	seg->p->tot_len -= len;
simon	0:350011bf8be7	1119
simon	0:350011bf8be7	1120	seg->p->payload = seg->tcphdr;
simon	0:350011bf8be7	1121
simon	0:350011bf8be7	1122	seg->tcphdr->chksum = 0;
simon	0:350011bf8be7	1123	#if CHECKSUM_GEN_TCP
simon	0:350011bf8be7	1124	#if TCP_CHECKSUM_ON_COPY
simon	0:350011bf8be7	1125	{
simon	0:350011bf8be7	1126	u32_t acc;
simon	0:350011bf8be7	1127	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
simon	0:350011bf8be7	1128	u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
simon	0:350011bf8be7	1129	&(pcb->remote_ip),
simon	0:350011bf8be7	1130	IP_PROTO_TCP, seg->p->tot_len);
simon	0:350011bf8be7	1131	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
simon	0:350011bf8be7	1132	if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
simon	0:350011bf8be7	1133	LWIP_ASSERT("data included but not checksummed",
simon	0:350011bf8be7	1134	seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
simon	0:350011bf8be7	1135	}
simon	0:350011bf8be7	1136
simon	0:350011bf8be7	1137	/* rebuild TCP header checksum (TCP header changes for retransmissions!) */
simon	0:350011bf8be7	1138	acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
simon	0:350011bf8be7	1139	&(pcb->remote_ip),
simon	0:350011bf8be7	1140	IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
simon	0:350011bf8be7	1141	/* add payload checksum */
simon	0:350011bf8be7	1142	if (seg->chksum_swapped) {
simon	0:350011bf8be7	1143	seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
simon	0:350011bf8be7	1144	seg->chksum_swapped = 0;
simon	0:350011bf8be7	1145	}
simon	0:350011bf8be7	1146	acc += (u16_t)~(seg->chksum);
simon	0:350011bf8be7	1147	seg->tcphdr->chksum = FOLD_U32T(acc);
simon	0:350011bf8be7	1148	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
simon	0:350011bf8be7	1149	if (chksum_slow != seg->tcphdr->chksum) {
simon	0:350011bf8be7	1150	LWIP_DEBUGF(TCP_DEBUG \| LWIP_DBG_LEVEL_WARNING,
simon	0:350011bf8be7	1151	("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
simon	0:350011bf8be7	1152	seg->tcphdr->chksum, chksum_slow));
simon	0:350011bf8be7	1153	seg->tcphdr->chksum = chksum_slow;
simon	0:350011bf8be7	1154	}
simon	0:350011bf8be7	1155	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
simon	0:350011bf8be7	1156	}
simon	0:350011bf8be7	1157	#else /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	1158	seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
simon	0:350011bf8be7	1159	&(pcb->remote_ip),
simon	0:350011bf8be7	1160	IP_PROTO_TCP, seg->p->tot_len);
simon	0:350011bf8be7	1161	#endif /* TCP_CHECKSUM_ON_COPY */
simon	0:350011bf8be7	1162	#endif /* CHECKSUM_GEN_TCP */
simon	0:350011bf8be7	1163	TCP_STATS_INC(tcp.xmit);
simon	0:350011bf8be7	1164
simon	0:350011bf8be7	1165	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: Before ip_out seqno = %"U32_F"\n",
simon	0:350011bf8be7	1166	htonl(seg->tcphdr->seqno))); //DG
simon	0:350011bf8be7	1167
simon	0:350011bf8be7	1168	#if LWIP_NETIF_HWADDRHINT
simon	0:350011bf8be7	1169	ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
simon	0:350011bf8be7	1170	IP_PROTO_TCP, &(pcb->addr_hint));
simon	0:350011bf8be7	1171	#else /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1172	ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
simon	0:350011bf8be7	1173	IP_PROTO_TCP);
simon	0:350011bf8be7	1174	#endif /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1175
simon	0:350011bf8be7	1176	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: After ip_out seqno = %"U32_F"\n",
simon	0:350011bf8be7	1177	htonl(seg->tcphdr->seqno))); //DG
simon	0:350011bf8be7	1178
simon	0:350011bf8be7	1179
simon	0:350011bf8be7	1180	}
simon	0:350011bf8be7	1181
simon	0:350011bf8be7	1182	/**
simon	0:350011bf8be7	1183	* Send a TCP RESET packet (empty segment with RST flag set) either to
simon	0:350011bf8be7	1184	* abort a connection or to show that there is no matching local connection
simon	0:350011bf8be7	1185	* for a received segment.
simon	0:350011bf8be7	1186	*
simon	0:350011bf8be7	1187	* Called by tcp_abort() (to abort a local connection), tcp_input() (if no
simon	0:350011bf8be7	1188	* matching local pcb was found), tcp_listen_input() (if incoming segment
simon	0:350011bf8be7	1189	* has ACK flag set) and tcp_process() (received segment in the wrong state)
simon	0:350011bf8be7	1190	*
simon	0:350011bf8be7	1191	* Since a RST segment is in most cases not sent for an active connection,
simon	0:350011bf8be7	1192	* tcp_rst() has a number of arguments that are taken from a tcp_pcb for
simon	0:350011bf8be7	1193	* most other segment output functions.
simon	0:350011bf8be7	1194	*
simon	0:350011bf8be7	1195	* @param seqno the sequence number to use for the outgoing segment
simon	0:350011bf8be7	1196	* @param ackno the acknowledge number to use for the outgoing segment
simon	0:350011bf8be7	1197	* @param local_ip the local IP address to send the segment from
simon	0:350011bf8be7	1198	* @param remote_ip the remote IP address to send the segment to
simon	0:350011bf8be7	1199	* @param local_port the local TCP port to send the segment from
simon	0:350011bf8be7	1200	* @param remote_port the remote TCP port to send the segment to
simon	0:350011bf8be7	1201	*/
simon	0:350011bf8be7	1202	void
simon	0:350011bf8be7	1203	tcp_rst(u32_t seqno, u32_t ackno,
simon	0:350011bf8be7	1204	ip_addr_t local_ip, ip_addr_t remote_ip,
simon	0:350011bf8be7	1205	u16_t local_port, u16_t remote_port)
simon	0:350011bf8be7	1206	{
simon	0:350011bf8be7	1207	struct pbuf *p;
simon	0:350011bf8be7	1208	struct tcp_hdr *tcphdr;
simon	0:350011bf8be7	1209	p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
simon	0:350011bf8be7	1210	if (p == NULL) {
simon	0:350011bf8be7	1211	LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
simon	0:350011bf8be7	1212	return;
simon	0:350011bf8be7	1213	}
simon	0:350011bf8be7	1214	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
simon	0:350011bf8be7	1215	(p->len >= sizeof(struct tcp_hdr)));
simon	0:350011bf8be7	1216
simon	0:350011bf8be7	1217	tcphdr = (struct tcp_hdr *)p->payload;
simon	0:350011bf8be7	1218	tcphdr->src = htons(local_port);
simon	0:350011bf8be7	1219	tcphdr->dest = htons(remote_port);
simon	0:350011bf8be7	1220	tcphdr->seqno = htonl(seqno);
simon	0:350011bf8be7	1221	tcphdr->ackno = htonl(ackno);
simon	0:350011bf8be7	1222	TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST \| TCP_ACK);
simon	0:350011bf8be7	1223	tcphdr->wnd = PP_HTONS(TCP_WND);
simon	0:350011bf8be7	1224	tcphdr->chksum = 0;
simon	0:350011bf8be7	1225	tcphdr->urgp = 0;
simon	0:350011bf8be7	1226
simon	0:350011bf8be7	1227	#if CHECKSUM_GEN_TCP
simon	0:350011bf8be7	1228	tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
simon	0:350011bf8be7	1229	IP_PROTO_TCP, p->tot_len);
simon	0:350011bf8be7	1230	#endif
simon	0:350011bf8be7	1231	TCP_STATS_INC(tcp.xmit);
simon	0:350011bf8be7	1232	snmp_inc_tcpoutrsts();
simon	0:350011bf8be7	1233	/* Send output with hardcoded TTL since we have no access to the pcb */
simon	0:350011bf8be7	1234	ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
simon	0:350011bf8be7	1235	pbuf_free(p);
simon	0:350011bf8be7	1236	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
simon	0:350011bf8be7	1237	}
simon	0:350011bf8be7	1238
simon	0:350011bf8be7	1239	/**
simon	0:350011bf8be7	1240	* Requeue all unacked segments for retransmission
simon	0:350011bf8be7	1241	*
simon	0:350011bf8be7	1242	* Called by tcp_slowtmr() for slow retransmission.
simon	0:350011bf8be7	1243	*
simon	0:350011bf8be7	1244	* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
simon	0:350011bf8be7	1245	*/
simon	0:350011bf8be7	1246	void
simon	0:350011bf8be7	1247	tcp_rexmit_rto(struct tcp_pcb *pcb)
simon	0:350011bf8be7	1248	{
simon	0:350011bf8be7	1249	struct tcp_seg *seg;
simon	0:350011bf8be7	1250
simon	0:350011bf8be7	1251	if (pcb->unacked == NULL) {
simon	0:350011bf8be7	1252	return;
simon	0:350011bf8be7	1253	}
simon	0:350011bf8be7	1254
simon	0:350011bf8be7	1255	/* Move all unacked segments to the head of the unsent queue */
simon	0:350011bf8be7	1256	for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
simon	0:350011bf8be7	1257	/* concatenate unsent queue after unacked queue */
simon	0:350011bf8be7	1258	seg->next = pcb->unsent;
simon	0:350011bf8be7	1259	/* unsent queue is the concatenated queue (of unacked, unsent) */
simon	0:350011bf8be7	1260	pcb->unsent = pcb->unacked;
simon	0:350011bf8be7	1261	/* unacked queue is now empty */
simon	0:350011bf8be7	1262	pcb->unacked = NULL;
simon	0:350011bf8be7	1263
simon	0:350011bf8be7	1264	/* increment number of retransmissions */
simon	0:350011bf8be7	1265	++pcb->nrtx;
simon	0:350011bf8be7	1266
simon	0:350011bf8be7	1267	/* Don't take any RTT measurements after retransmitting. */
simon	0:350011bf8be7	1268	pcb->rttest = 0;
simon	0:350011bf8be7	1269
simon	0:350011bf8be7	1270	/* Do the actual retransmission */
simon	0:350011bf8be7	1271	tcp_output(pcb);
simon	0:350011bf8be7	1272	}
simon	0:350011bf8be7	1273
simon	0:350011bf8be7	1274	/**
simon	0:350011bf8be7	1275	* Requeue the first unacked segment for retransmission
simon	0:350011bf8be7	1276	*
simon	0:350011bf8be7	1277	* Called by tcp_receive() for fast retramsmit.
simon	0:350011bf8be7	1278	*
simon	0:350011bf8be7	1279	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
simon	0:350011bf8be7	1280	*/
simon	0:350011bf8be7	1281	void
simon	0:350011bf8be7	1282	tcp_rexmit(struct tcp_pcb *pcb)
simon	0:350011bf8be7	1283	{
simon	0:350011bf8be7	1284	struct tcp_seg *seg;
simon	0:350011bf8be7	1285	struct tcp_seg **cur_seg;
simon	0:350011bf8be7	1286
simon	0:350011bf8be7	1287	if (pcb->unacked == NULL) {
simon	0:350011bf8be7	1288	return;
simon	0:350011bf8be7	1289	}
simon	0:350011bf8be7	1290
simon	0:350011bf8be7	1291	/* Move the first unacked segment to the unsent queue */
simon	0:350011bf8be7	1292	/* Keep the unsent queue sorted. */
simon	0:350011bf8be7	1293	seg = pcb->unacked;
simon	0:350011bf8be7	1294	pcb->unacked = seg->next;
simon	0:350011bf8be7	1295
simon	0:350011bf8be7	1296	cur_seg = &(pcb->unsent);
simon	0:350011bf8be7	1297	while (*cur_seg &&
simon	0:350011bf8be7	1298	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
simon	0:350011bf8be7	1299	cur_seg = &((*cur_seg)->next );
simon	0:350011bf8be7	1300	}
simon	0:350011bf8be7	1301	seg->next = *cur_seg;
simon	0:350011bf8be7	1302	*cur_seg = seg;
simon	0:350011bf8be7	1303
simon	0:350011bf8be7	1304	++pcb->nrtx;
simon	0:350011bf8be7	1305
simon	0:350011bf8be7	1306	/* Don't take any rtt measurements after retransmitting. */
simon	0:350011bf8be7	1307	pcb->rttest = 0;
simon	0:350011bf8be7	1308
simon	0:350011bf8be7	1309	/* Do the actual retransmission. */
simon	0:350011bf8be7	1310	snmp_inc_tcpretranssegs();
simon	0:350011bf8be7	1311	/* No need to call tcp_output: we are always called from tcp_input()
simon	0:350011bf8be7	1312	and thus tcp_output directly returns. */
simon	0:350011bf8be7	1313	}
simon	0:350011bf8be7	1314
simon	0:350011bf8be7	1315
simon	0:350011bf8be7	1316	/**
simon	0:350011bf8be7	1317	* Handle retransmission after three dupacks received
simon	0:350011bf8be7	1318	*
simon	0:350011bf8be7	1319	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
simon	0:350011bf8be7	1320	*/
simon	0:350011bf8be7	1321	void
simon	0:350011bf8be7	1322	tcp_rexmit_fast(struct tcp_pcb *pcb)
simon	0:350011bf8be7	1323	{
simon	0:350011bf8be7	1324	if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
simon	0:350011bf8be7	1325	/* This is fast retransmit. Retransmit the first unacked segment. */
simon	0:350011bf8be7	1326	LWIP_DEBUGF(TCP_FR_DEBUG,
simon	0:350011bf8be7	1327	("tcp_receive: dupacks %"U16_F" (%"U32_F
simon	0:350011bf8be7	1328	"), fast retransmit %"U32_F"\n",
simon	0:350011bf8be7	1329	(u16_t)pcb->dupacks, pcb->lastack,
simon	0:350011bf8be7	1330	ntohl(pcb->unacked->tcphdr->seqno)));
simon	0:350011bf8be7	1331	tcp_rexmit(pcb);
simon	0:350011bf8be7	1332
simon	0:350011bf8be7	1333	/* Set ssthresh to half of the minimum of the current
simon	0:350011bf8be7	1334	* cwnd and the advertised window */
simon	0:350011bf8be7	1335	if (pcb->cwnd > pcb->snd_wnd) {
simon	0:350011bf8be7	1336	pcb->ssthresh = pcb->snd_wnd / 2;
simon	0:350011bf8be7	1337	} else {
simon	0:350011bf8be7	1338	pcb->ssthresh = pcb->cwnd / 2;
simon	0:350011bf8be7	1339	}
simon	0:350011bf8be7	1340
simon	0:350011bf8be7	1341	/* The minimum value for ssthresh should be 2 MSS */
simon	0:350011bf8be7	1342	if (pcb->ssthresh < 2*pcb->mss) {
simon	0:350011bf8be7	1343	LWIP_DEBUGF(TCP_FR_DEBUG,
simon	0:350011bf8be7	1344	("tcp_receive: The minimum value for ssthresh %"U16_F
simon	0:350011bf8be7	1345	" should be min 2 mss %"U16_F"...\n",
simon	0:350011bf8be7	1346	pcb->ssthresh, 2*pcb->mss));
simon	0:350011bf8be7	1347	pcb->ssthresh = 2*pcb->mss;
simon	0:350011bf8be7	1348	}
simon	0:350011bf8be7	1349
simon	0:350011bf8be7	1350	pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
simon	0:350011bf8be7	1351	pcb->flags \|= TF_INFR;
simon	0:350011bf8be7	1352	}
simon	0:350011bf8be7	1353	}
simon	0:350011bf8be7	1354
simon	0:350011bf8be7	1355
simon	0:350011bf8be7	1356	/**
simon	0:350011bf8be7	1357	* Send keepalive packets to keep a connection active although
simon	0:350011bf8be7	1358	* no data is sent over it.
simon	0:350011bf8be7	1359	*
simon	0:350011bf8be7	1360	* Called by tcp_slowtmr()
simon	0:350011bf8be7	1361	*
simon	0:350011bf8be7	1362	* @param pcb the tcp_pcb for which to send a keepalive packet
simon	0:350011bf8be7	1363	*/
simon	0:350011bf8be7	1364	void
simon	0:350011bf8be7	1365	tcp_keepalive(struct tcp_pcb *pcb)
simon	0:350011bf8be7	1366	{
simon	0:350011bf8be7	1367	struct pbuf *p;
simon	0:350011bf8be7	1368	struct tcp_hdr *tcphdr;
simon	0:350011bf8be7	1369
simon	0:350011bf8be7	1370	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
simon	0:350011bf8be7	1371	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
simon	0:350011bf8be7	1372	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
simon	0:350011bf8be7	1373
simon	0:350011bf8be7	1374	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
simon	0:350011bf8be7	1375	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
simon	0:350011bf8be7	1376
simon	0:350011bf8be7	1377	p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
simon	0:350011bf8be7	1378	if(p == NULL) {
simon	0:350011bf8be7	1379	LWIP_DEBUGF(TCP_DEBUG,
simon	0:350011bf8be7	1380	("tcp_keepalive: could not allocate memory for pbuf\n"));
simon	0:350011bf8be7	1381	return;
simon	0:350011bf8be7	1382	}
simon	0:350011bf8be7	1383	tcphdr = (struct tcp_hdr *)p->payload;
simon	0:350011bf8be7	1384
simon	0:350011bf8be7	1385	#if CHECKSUM_GEN_TCP
simon	0:350011bf8be7	1386	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
simon	0:350011bf8be7	1387	IP_PROTO_TCP, p->tot_len);
simon	0:350011bf8be7	1388	#endif
simon	0:350011bf8be7	1389	TCP_STATS_INC(tcp.xmit);
simon	0:350011bf8be7	1390
simon	0:350011bf8be7	1391	/* Send output to IP */
simon	0:350011bf8be7	1392	#if LWIP_NETIF_HWADDRHINT
simon	0:350011bf8be7	1393	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
simon	0:350011bf8be7	1394	&(pcb->addr_hint));
simon	0:350011bf8be7	1395	#else /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1396	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
simon	0:350011bf8be7	1397	#endif /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1398
simon	0:350011bf8be7	1399	pbuf_free(p);
simon	0:350011bf8be7	1400
simon	0:350011bf8be7	1401	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
simon	0:350011bf8be7	1402	pcb->snd_nxt - 1, pcb->rcv_nxt));
simon	0:350011bf8be7	1403	}
simon	0:350011bf8be7	1404
simon	0:350011bf8be7	1405
simon	0:350011bf8be7	1406	/**
simon	0:350011bf8be7	1407	* Send persist timer zero-window probes to keep a connection active
simon	0:350011bf8be7	1408	* when a window update is lost.
simon	0:350011bf8be7	1409	*
simon	0:350011bf8be7	1410	* Called by tcp_slowtmr()
simon	0:350011bf8be7	1411	*
simon	0:350011bf8be7	1412	* @param pcb the tcp_pcb for which to send a zero-window probe packet
simon	0:350011bf8be7	1413	*/
simon	0:350011bf8be7	1414	void
simon	0:350011bf8be7	1415	tcp_zero_window_probe(struct tcp_pcb *pcb)
simon	0:350011bf8be7	1416	{
simon	0:350011bf8be7	1417	struct pbuf *p;
simon	0:350011bf8be7	1418	struct tcp_hdr *tcphdr;
simon	0:350011bf8be7	1419	struct tcp_seg *seg;
simon	0:350011bf8be7	1420	u16_t len;
simon	0:350011bf8be7	1421	u8_t is_fin;
simon	0:350011bf8be7	1422
simon	0:350011bf8be7	1423	LWIP_DEBUGF(TCP_DEBUG,
simon	0:350011bf8be7	1424	("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
simon	0:350011bf8be7	1425	U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
simon	0:350011bf8be7	1426	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
simon	0:350011bf8be7	1427	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
simon	0:350011bf8be7	1428
simon	0:350011bf8be7	1429	LWIP_DEBUGF(TCP_DEBUG,
simon	0:350011bf8be7	1430	("tcp_zero_window_probe: tcp_ticks %"U32_F
simon	0:350011bf8be7	1431	" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
simon	0:350011bf8be7	1432	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
simon	0:350011bf8be7	1433
simon	0:350011bf8be7	1434	seg = pcb->unacked;
simon	0:350011bf8be7	1435
simon	0:350011bf8be7	1436	if(seg == NULL) {
simon	0:350011bf8be7	1437	seg = pcb->unsent;
simon	0:350011bf8be7	1438	}
simon	0:350011bf8be7	1439	if(seg == NULL) {
simon	0:350011bf8be7	1440	return;
simon	0:350011bf8be7	1441	}
simon	0:350011bf8be7	1442
simon	0:350011bf8be7	1443	is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
simon	0:350011bf8be7	1444	/* we want to send one seqno: either FIN or data (no options) */
simon	0:350011bf8be7	1445	len = is_fin ? 0 : 1;
simon	0:350011bf8be7	1446
simon	0:350011bf8be7	1447	p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
simon	0:350011bf8be7	1448	if(p == NULL) {
simon	0:350011bf8be7	1449	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
simon	0:350011bf8be7	1450	return;
simon	0:350011bf8be7	1451	}
simon	0:350011bf8be7	1452	tcphdr = (struct tcp_hdr *)p->payload;
simon	0:350011bf8be7	1453
simon	0:350011bf8be7	1454	if (is_fin) {
simon	0:350011bf8be7	1455	/* FIN segment, no data */
simon	0:350011bf8be7	1456	TCPH_FLAGS_SET(tcphdr, TCP_ACK \| TCP_FIN);
simon	0:350011bf8be7	1457	} else {
simon	0:350011bf8be7	1458	/* Data segment, copy in one byte from the head of the unacked queue */
simon	0:350011bf8be7	1459	((char )p->payload + TCP_HLEN) = (char )seg->dataptr;
simon	0:350011bf8be7	1460	}
simon	0:350011bf8be7	1461
simon	0:350011bf8be7	1462	#if CHECKSUM_GEN_TCP
simon	0:350011bf8be7	1463	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
simon	0:350011bf8be7	1464	IP_PROTO_TCP, p->tot_len);
simon	0:350011bf8be7	1465	#endif
simon	0:350011bf8be7	1466	TCP_STATS_INC(tcp.xmit);
simon	0:350011bf8be7	1467
simon	0:350011bf8be7	1468	/* Send output to IP */
simon	0:350011bf8be7	1469	#if LWIP_NETIF_HWADDRHINT
simon	0:350011bf8be7	1470	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
simon	0:350011bf8be7	1471	&(pcb->addr_hint));
simon	0:350011bf8be7	1472	#else /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1473	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
simon	0:350011bf8be7	1474	#endif /* LWIP_NETIF_HWADDRHINT*/
simon	0:350011bf8be7	1475
simon	0:350011bf8be7	1476	pbuf_free(p);
simon	0:350011bf8be7	1477
simon	0:350011bf8be7	1478	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
simon	0:350011bf8be7	1479	" ackno %"U32_F".\n",
simon	0:350011bf8be7	1480	pcb->snd_nxt - 1, pcb->rcv_nxt));
simon	0:350011bf8be7	1481	}
simon	0:350011bf8be7	1482	#endif /* LWIP_TCP */

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Type:	Library
Created:	23 Nov 2010
Imports:	589
Forks:	0
Commits:	1
Dependents:	5
Dependencies:	0
Followers:	5

lwip/core/tcp_out.c@0:350011bf8be7, 2010-11-23 (annotated)

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