NetServicesMin - Stripped down version of Segundos NetService libr…

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Stripped down version of Segundos NetService library (http://mbed.org/users/segundo/libraries/NetServices ). I have removed all NetServices, and all functions which had been disabled. Use this version when you need only pure TCP or UDP functions - this library compiles faster.

Dependencies: lwip lwip-sys

Dependents: christmasLights device_server pop3demo device_server_udp ... more

lwip/core/tcp_out.c@0:8b387bed54c2, 2011-01-10 (annotated)

Committer:: hlipka
Date:: Mon Jan 10 21:03:11 2011 +0000
Revision:: 0:8b387bed54c2

initial version

Who changed what in which revision?

User	Revision	Line number	New contents of line
hlipka	0:8b387bed54c2	1	/**
hlipka	0:8b387bed54c2	2	* @file
hlipka	0:8b387bed54c2	3	* Transmission Control Protocol, outgoing traffic
hlipka	0:8b387bed54c2	4	*
hlipka	0:8b387bed54c2	5	* The output functions of TCP.
hlipka	0:8b387bed54c2	6	*
hlipka	0:8b387bed54c2	7	*/
hlipka	0:8b387bed54c2	8
hlipka	0:8b387bed54c2	9	/*
hlipka	0:8b387bed54c2	10	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
hlipka	0:8b387bed54c2	11	* All rights reserved.
hlipka	0:8b387bed54c2	12	*
hlipka	0:8b387bed54c2	13	* Redistribution and use in source and binary forms, with or without modification,
hlipka	0:8b387bed54c2	14	* are permitted provided that the following conditions are met:
hlipka	0:8b387bed54c2	15	*
hlipka	0:8b387bed54c2	16	* 1. Redistributions of source code must retain the above copyright notice,
hlipka	0:8b387bed54c2	17	* this list of conditions and the following disclaimer.
hlipka	0:8b387bed54c2	18	* 2. Redistributions in binary form must reproduce the above copyright notice,
hlipka	0:8b387bed54c2	19	* this list of conditions and the following disclaimer in the documentation
hlipka	0:8b387bed54c2	20	* and/or other materials provided with the distribution.
hlipka	0:8b387bed54c2	21	* 3. The name of the author may not be used to endorse or promote products
hlipka	0:8b387bed54c2	22	* derived from this software without specific prior written permission.
hlipka	0:8b387bed54c2	23	*
hlipka	0:8b387bed54c2	24	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
hlipka	0:8b387bed54c2	25	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
hlipka	0:8b387bed54c2	26	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
hlipka	0:8b387bed54c2	27	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
hlipka	0:8b387bed54c2	28	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
hlipka	0:8b387bed54c2	29	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
hlipka	0:8b387bed54c2	30	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
hlipka	0:8b387bed54c2	31	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
hlipka	0:8b387bed54c2	32	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
hlipka	0:8b387bed54c2	33	* OF SUCH DAMAGE.
hlipka	0:8b387bed54c2	34	*
hlipka	0:8b387bed54c2	35	* This file is part of the lwIP TCP/IP stack.
hlipka	0:8b387bed54c2	36	*
hlipka	0:8b387bed54c2	37	* Author: Adam Dunkels <adam@sics.se>
hlipka	0:8b387bed54c2	38	*
hlipka	0:8b387bed54c2	39	*/
hlipka	0:8b387bed54c2	40
hlipka	0:8b387bed54c2	41	#include "lwip/opt.h"
hlipka	0:8b387bed54c2	42
hlipka	0:8b387bed54c2	43	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
hlipka	0:8b387bed54c2	44
hlipka	0:8b387bed54c2	45	#include "lwip/tcp_impl.h"
hlipka	0:8b387bed54c2	46	#include "lwip/def.h"
hlipka	0:8b387bed54c2	47	#include "lwip/mem.h"
hlipka	0:8b387bed54c2	48	#include "lwip/memp.h"
hlipka	0:8b387bed54c2	49	#include "lwip/sys.h"
hlipka	0:8b387bed54c2	50	#include "lwip/ip_addr.h"
hlipka	0:8b387bed54c2	51	#include "lwip/netif.h"
hlipka	0:8b387bed54c2	52	#include "lwip/inet_chksum.h"
hlipka	0:8b387bed54c2	53	#include "lwip/stats.h"
hlipka	0:8b387bed54c2	54	#include "lwip/snmp.h"
hlipka	0:8b387bed54c2	55
hlipka	0:8b387bed54c2	56	#include <string.h>
hlipka	0:8b387bed54c2	57
hlipka	0:8b387bed54c2	58	/* Define some copy-macros for checksum-on-copy so that the code looks
hlipka	0:8b387bed54c2	59	nicer by preventing too many ifdef's. */
hlipka	0:8b387bed54c2	60	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	61	#define TCP_DATA_COPY(dst, src, len, seg) do { \
hlipka	0:8b387bed54c2	62	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
hlipka	0:8b387bed54c2	63	len, &seg->chksum, &seg->chksum_swapped); \
hlipka	0:8b387bed54c2	64	seg->flags \|= TF_SEG_DATA_CHECKSUMMED; } while(0)
hlipka	0:8b387bed54c2	65	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
hlipka	0:8b387bed54c2	66	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
hlipka	0:8b387bed54c2	67	#else /* TCP_CHECKSUM_ON_COPY*/
hlipka	0:8b387bed54c2	68	#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
hlipka	0:8b387bed54c2	69	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
hlipka	0:8b387bed54c2	70	#endif /* TCP_CHECKSUM_ON_COPY*/
hlipka	0:8b387bed54c2	71
hlipka	0:8b387bed54c2	72	/** Define this to 1 for an extra check that the output checksum is valid
hlipka	0:8b387bed54c2	73	* (usefule when the checksum is generated by the application, not the stack) */
hlipka	0:8b387bed54c2	74	#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
hlipka	0:8b387bed54c2	75	#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
hlipka	0:8b387bed54c2	76	#endif
hlipka	0:8b387bed54c2	77
hlipka	0:8b387bed54c2	78	/* Forward declarations.*/
hlipka	0:8b387bed54c2	79	static void tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb);
hlipka	0:8b387bed54c2	80
hlipka	0:8b387bed54c2	81	/** Allocate a pbuf and create a tcphdr at p->payload, used for output
hlipka	0:8b387bed54c2	82	* functions other than the default tcp_output -> tcp_output_segment
hlipka	0:8b387bed54c2	83	* (e.g. tcp_send_empty_ack, etc.)
hlipka	0:8b387bed54c2	84	*
hlipka	0:8b387bed54c2	85	* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
hlipka	0:8b387bed54c2	86	* @param optlen length of header-options
hlipka	0:8b387bed54c2	87	* @param datalen length of tcp data to reserve in pbuf
hlipka	0:8b387bed54c2	88	* @param seqno_be seqno in network byte order (big-endian)
hlipka	0:8b387bed54c2	89	* @return pbuf with p->payload being the tcp_hdr
hlipka	0:8b387bed54c2	90	*/
hlipka	0:8b387bed54c2	91	static struct pbuf *
hlipka	0:8b387bed54c2	92	tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
hlipka	0:8b387bed54c2	93	u32_t seqno_be /* already in network byte order */)
hlipka	0:8b387bed54c2	94	{
hlipka	0:8b387bed54c2	95	struct tcp_hdr *tcphdr;
hlipka	0:8b387bed54c2	96	struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
hlipka	0:8b387bed54c2	97	if (p != NULL) {
hlipka	0:8b387bed54c2	98	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
hlipka	0:8b387bed54c2	99	(p->len >= TCP_HLEN + optlen));
hlipka	0:8b387bed54c2	100	tcphdr = (struct tcp_hdr *)p->payload;
hlipka	0:8b387bed54c2	101	tcphdr->src = htons(pcb->local_port);
hlipka	0:8b387bed54c2	102	tcphdr->dest = htons(pcb->remote_port);
hlipka	0:8b387bed54c2	103	tcphdr->seqno = seqno_be;
hlipka	0:8b387bed54c2	104	tcphdr->ackno = htonl(pcb->rcv_nxt);
hlipka	0:8b387bed54c2	105	TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
hlipka	0:8b387bed54c2	106	tcphdr->wnd = htons(pcb->rcv_ann_wnd);
hlipka	0:8b387bed54c2	107	tcphdr->chksum = 0;
hlipka	0:8b387bed54c2	108	tcphdr->urgp = 0;
hlipka	0:8b387bed54c2	109
hlipka	0:8b387bed54c2	110	/* If we're sending a packet, update the announced right window edge */
hlipka	0:8b387bed54c2	111	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
hlipka	0:8b387bed54c2	112	}
hlipka	0:8b387bed54c2	113	return p;
hlipka	0:8b387bed54c2	114	}
hlipka	0:8b387bed54c2	115
hlipka	0:8b387bed54c2	116	/**
hlipka	0:8b387bed54c2	117	* Called by tcp_close() to send a segment including FIN flag but not data.
hlipka	0:8b387bed54c2	118	*
hlipka	0:8b387bed54c2	119	* @param pcb the tcp_pcb over which to send a segment
hlipka	0:8b387bed54c2	120	* @return ERR_OK if sent, another err_t otherwise
hlipka	0:8b387bed54c2	121	*/
hlipka	0:8b387bed54c2	122	err_t
hlipka	0:8b387bed54c2	123	tcp_send_fin(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	124	{
hlipka	0:8b387bed54c2	125	/* first, try to add the fin to the last unsent segment */
hlipka	0:8b387bed54c2	126	if (pcb->unsent != NULL) {
hlipka	0:8b387bed54c2	127	struct tcp_seg *last_unsent;
hlipka	0:8b387bed54c2	128	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
hlipka	0:8b387bed54c2	129	last_unsent = last_unsent->next);
hlipka	0:8b387bed54c2	130
hlipka	0:8b387bed54c2	131	if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN \| TCP_FIN \| TCP_RST)) == 0) {
hlipka	0:8b387bed54c2	132	/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
hlipka	0:8b387bed54c2	133	TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
hlipka	0:8b387bed54c2	134	return ERR_OK;
hlipka	0:8b387bed54c2	135	}
hlipka	0:8b387bed54c2	136	}
hlipka	0:8b387bed54c2	137	/* no data, no length, flags, copy=1, no optdata */
hlipka	0:8b387bed54c2	138	return tcp_enqueue_flags(pcb, TCP_FIN);
hlipka	0:8b387bed54c2	139	}
hlipka	0:8b387bed54c2	140
hlipka	0:8b387bed54c2	141	/**
hlipka	0:8b387bed54c2	142	* Create a TCP segment with prefilled header.
hlipka	0:8b387bed54c2	143	*
hlipka	0:8b387bed54c2	144	* Called by tcp_write and tcp_enqueue_flags.
hlipka	0:8b387bed54c2	145	*
hlipka	0:8b387bed54c2	146	* @param pcb Protocol control block for the TCP connection.
hlipka	0:8b387bed54c2	147	* @param p pbuf that is used to hold the TCP header.
hlipka	0:8b387bed54c2	148	* @param flags TCP flags for header.
hlipka	0:8b387bed54c2	149	* @param seqno TCP sequence number of this packet
hlipka	0:8b387bed54c2	150	* @param optflags options to include in TCP header
hlipka	0:8b387bed54c2	151	* @return a new tcp_seg pointing to p, or NULL.
hlipka	0:8b387bed54c2	152	* The TCP header is filled in except ackno and wnd.
hlipka	0:8b387bed54c2	153	* p is freed on failure.
hlipka	0:8b387bed54c2	154	*/
hlipka	0:8b387bed54c2	155	static struct tcp_seg *
hlipka	0:8b387bed54c2	156	tcp_create_segment(struct tcp_pcb pcb, struct pbuf p, u8_t flags, u32_t seqno, u8_t optflags)
hlipka	0:8b387bed54c2	157	{
hlipka	0:8b387bed54c2	158	struct tcp_seg *seg;
hlipka	0:8b387bed54c2	159	u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
hlipka	0:8b387bed54c2	160
hlipka	0:8b387bed54c2	161	if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
hlipka	0:8b387bed54c2	162	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no memory.\n"));
hlipka	0:8b387bed54c2	163	pbuf_free(p);
hlipka	0:8b387bed54c2	164	return NULL;
hlipka	0:8b387bed54c2	165	}
hlipka	0:8b387bed54c2	166	seg->flags = optflags;
hlipka	0:8b387bed54c2	167	seg->next = NULL;
hlipka	0:8b387bed54c2	168	seg->p = p;
hlipka	0:8b387bed54c2	169	seg->dataptr = p->payload;
hlipka	0:8b387bed54c2	170	seg->len = p->tot_len - optlen;
hlipka	0:8b387bed54c2	171	#if TCP_OVERSIZE_DBGCHECK
hlipka	0:8b387bed54c2	172	seg->oversize_left = 0;
hlipka	0:8b387bed54c2	173	#endif /* TCP_OVERSIZE_DBGCHECK */
hlipka	0:8b387bed54c2	174	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	175	seg->chksum = 0;
hlipka	0:8b387bed54c2	176	seg->chksum_swapped = 0;
hlipka	0:8b387bed54c2	177	/* check optflags */
hlipka	0:8b387bed54c2	178	LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
hlipka	0:8b387bed54c2	179	(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
hlipka	0:8b387bed54c2	180	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	181
hlipka	0:8b387bed54c2	182	/* build TCP header */
hlipka	0:8b387bed54c2	183	if (pbuf_header(p, TCP_HLEN)) {
hlipka	0:8b387bed54c2	184	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
hlipka	0:8b387bed54c2	185	TCP_STATS_INC(tcp.err);
hlipka	0:8b387bed54c2	186	tcp_seg_free(seg);
hlipka	0:8b387bed54c2	187	return NULL;
hlipka	0:8b387bed54c2	188	}
hlipka	0:8b387bed54c2	189	seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
hlipka	0:8b387bed54c2	190	seg->tcphdr->src = htons(pcb->local_port);
hlipka	0:8b387bed54c2	191	seg->tcphdr->dest = htons(pcb->remote_port);
hlipka	0:8b387bed54c2	192	seg->tcphdr->seqno = htonl(seqno);
hlipka	0:8b387bed54c2	193	/* ackno is set in tcp_output */
hlipka	0:8b387bed54c2	194	TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
hlipka	0:8b387bed54c2	195	/* wnd and chksum are set in tcp_output */
hlipka	0:8b387bed54c2	196	seg->tcphdr->urgp = 0;
hlipka	0:8b387bed54c2	197	return seg;
hlipka	0:8b387bed54c2	198	}
hlipka	0:8b387bed54c2	199
hlipka	0:8b387bed54c2	200	/**
hlipka	0:8b387bed54c2	201	* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
hlipka	0:8b387bed54c2	202	*
hlipka	0:8b387bed54c2	203	* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
hlipka	0:8b387bed54c2	204	* there may be extra bytes available at the end.
hlipka	0:8b387bed54c2	205	*
hlipka	0:8b387bed54c2	206	* @param layer flag to define header size.
hlipka	0:8b387bed54c2	207	* @param length size of the pbuf's payload.
hlipka	0:8b387bed54c2	208	* @param max_length maximum usable size of payload+oversize.
hlipka	0:8b387bed54c2	209	* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
hlipka	0:8b387bed54c2	210	* @param pcb The TCP connection that willo enqueue the pbuf.
hlipka	0:8b387bed54c2	211	* @param apiflags API flags given to tcp_write.
hlipka	0:8b387bed54c2	212	* @param first_seg true when this pbuf will be used in the first enqueued segment.
hlipka	0:8b387bed54c2	213	* @param
hlipka	0:8b387bed54c2	214	*/
hlipka	0:8b387bed54c2	215	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	216	static struct pbuf *
hlipka	0:8b387bed54c2	217	tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
hlipka	0:8b387bed54c2	218	u16_t oversize, struct tcp_pcb pcb, u8_t apiflags,
hlipka	0:8b387bed54c2	219	u8_t first_seg)
hlipka	0:8b387bed54c2	220	{
hlipka	0:8b387bed54c2	221	struct pbuf *p;
hlipka	0:8b387bed54c2	222	u16_t alloc = length;
hlipka	0:8b387bed54c2	223
hlipka	0:8b387bed54c2	224	#if LWIP_NETIF_TX_SINGLE_PBUF
hlipka	0:8b387bed54c2	225	LWIP_UNUSED_ARG(max_length);
hlipka	0:8b387bed54c2	226	LWIP_UNUSED_ARG(pcb);
hlipka	0:8b387bed54c2	227	LWIP_UNUSED_ARG(apiflags);
hlipka	0:8b387bed54c2	228	LWIP_UNUSED_ARG(first_seg);
hlipka	0:8b387bed54c2	229	/* always create MSS-sized pbufs */
hlipka	0:8b387bed54c2	230	alloc = TCP_MSS;
hlipka	0:8b387bed54c2	231	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
hlipka	0:8b387bed54c2	232	if (length < max_length) {
hlipka	0:8b387bed54c2	233	/* Should we allocate an oversized pbuf, or just the minimum
hlipka	0:8b387bed54c2	234	* length required? If tcp_write is going to be called again
hlipka	0:8b387bed54c2	235	* before this segment is transmitted, we want the oversized
hlipka	0:8b387bed54c2	236	* buffer. If the segment will be transmitted immediately, we can
hlipka	0:8b387bed54c2	237	* save memory by allocating only length. We use a simple
hlipka	0:8b387bed54c2	238	* heuristic based on the following information:
hlipka	0:8b387bed54c2	239	*
hlipka	0:8b387bed54c2	240	* Did the user set TCP_WRITE_FLAG_MORE?
hlipka	0:8b387bed54c2	241	*
hlipka	0:8b387bed54c2	242	* Will the Nagle algorithm defer transmission of this segment?
hlipka	0:8b387bed54c2	243	*/
hlipka	0:8b387bed54c2	244	if ((apiflags & TCP_WRITE_FLAG_MORE) \|\|
hlipka	0:8b387bed54c2	245	(!(pcb->flags & TF_NODELAY) &&
hlipka	0:8b387bed54c2	246	(!first_seg \|\|
hlipka	0:8b387bed54c2	247	pcb->unsent != NULL \|\|
hlipka	0:8b387bed54c2	248	pcb->unacked != NULL))) {
hlipka	0:8b387bed54c2	249	alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
hlipka	0:8b387bed54c2	250	}
hlipka	0:8b387bed54c2	251	}
hlipka	0:8b387bed54c2	252	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
hlipka	0:8b387bed54c2	253	p = pbuf_alloc(layer, alloc, PBUF_RAM);
hlipka	0:8b387bed54c2	254	if (p == NULL) {
hlipka	0:8b387bed54c2	255	return NULL;
hlipka	0:8b387bed54c2	256	}
hlipka	0:8b387bed54c2	257	LWIP_ASSERT("need unchained pbuf", p->next == NULL);
hlipka	0:8b387bed54c2	258	*oversize = p->len - length;
hlipka	0:8b387bed54c2	259	/* trim p->len to the currently used size */
hlipka	0:8b387bed54c2	260	p->len = p->tot_len = length;
hlipka	0:8b387bed54c2	261	return p;
hlipka	0:8b387bed54c2	262	}
hlipka	0:8b387bed54c2	263	#else /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	264	#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
hlipka	0:8b387bed54c2	265	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	266
hlipka	0:8b387bed54c2	267	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	268	/** Add a checksum of newly added data to the segment */
hlipka	0:8b387bed54c2	269	static void
hlipka	0:8b387bed54c2	270	tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
hlipka	0:8b387bed54c2	271	u8_t *seg_chksum_swapped)
hlipka	0:8b387bed54c2	272	{
hlipka	0:8b387bed54c2	273	u32_t helper;
hlipka	0:8b387bed54c2	274	/* add chksum to old chksum and fold to u16_t */
hlipka	0:8b387bed54c2	275	helper = chksum + *seg_chksum;
hlipka	0:8b387bed54c2	276	chksum = FOLD_U32T(helper);
hlipka	0:8b387bed54c2	277	if ((len & 1) != 0) {
hlipka	0:8b387bed54c2	278	seg_chksum_swapped = 1 - seg_chksum_swapped;
hlipka	0:8b387bed54c2	279	chksum = SWAP_BYTES_IN_WORD(chksum);
hlipka	0:8b387bed54c2	280	}
hlipka	0:8b387bed54c2	281	*seg_chksum = chksum;
hlipka	0:8b387bed54c2	282	}
hlipka	0:8b387bed54c2	283	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	284
hlipka	0:8b387bed54c2	285	/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
hlipka	0:8b387bed54c2	286	*
hlipka	0:8b387bed54c2	287	* @param pcb the tcp pcb to check for
hlipka	0:8b387bed54c2	288	* @param len length of data to send (checked agains snd_buf)
hlipka	0:8b387bed54c2	289	* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
hlipka	0:8b387bed54c2	290	*/
hlipka	0:8b387bed54c2	291	static err_t
hlipka	0:8b387bed54c2	292	tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
hlipka	0:8b387bed54c2	293	{
hlipka	0:8b387bed54c2	294	/* connection is in invalid state for data transmission? */
hlipka	0:8b387bed54c2	295	if ((pcb->state != ESTABLISHED) &&
hlipka	0:8b387bed54c2	296	(pcb->state != CLOSE_WAIT) &&
hlipka	0:8b387bed54c2	297	(pcb->state != SYN_SENT) &&
hlipka	0:8b387bed54c2	298	(pcb->state != SYN_RCVD)) {
hlipka	0:8b387bed54c2	299	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_STATE \| LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
hlipka	0:8b387bed54c2	300	return ERR_CONN;
hlipka	0:8b387bed54c2	301	} else if (len == 0) {
hlipka	0:8b387bed54c2	302	return ERR_OK;
hlipka	0:8b387bed54c2	303	}
hlipka	0:8b387bed54c2	304
hlipka	0:8b387bed54c2	305	/* fail on too much data */
hlipka	0:8b387bed54c2	306	if (len > pcb->snd_buf) {
hlipka	0:8b387bed54c2	307	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
hlipka	0:8b387bed54c2	308	len, pcb->snd_buf));
hlipka	0:8b387bed54c2	309	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	310	return ERR_MEM;
hlipka	0:8b387bed54c2	311	}
hlipka	0:8b387bed54c2	312
hlipka	0:8b387bed54c2	313	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
hlipka	0:8b387bed54c2	314
hlipka	0:8b387bed54c2	315	/* If total number of pbufs on the unsent/unacked queues exceeds the
hlipka	0:8b387bed54c2	316	* configured maximum, return an error */
hlipka	0:8b387bed54c2	317	/* check for configured max queuelen and possible overflow */
hlipka	0:8b387bed54c2	318	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
hlipka	0:8b387bed54c2	319	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
hlipka	0:8b387bed54c2	320	pcb->snd_queuelen, TCP_SND_QUEUELEN));
hlipka	0:8b387bed54c2	321	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	322	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	323	return ERR_MEM;
hlipka	0:8b387bed54c2	324	}
hlipka	0:8b387bed54c2	325	if (pcb->snd_queuelen != 0) {
hlipka	0:8b387bed54c2	326	LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
hlipka	0:8b387bed54c2	327	pcb->unacked != NULL \|\| pcb->unsent != NULL);
hlipka	0:8b387bed54c2	328	} else {
hlipka	0:8b387bed54c2	329	LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
hlipka	0:8b387bed54c2	330	pcb->unacked == NULL && pcb->unsent == NULL);
hlipka	0:8b387bed54c2	331	}
hlipka	0:8b387bed54c2	332	return ERR_OK;
hlipka	0:8b387bed54c2	333	}
hlipka	0:8b387bed54c2	334
hlipka	0:8b387bed54c2	335	/**
hlipka	0:8b387bed54c2	336	* Write data for sending (but does not send it immediately).
hlipka	0:8b387bed54c2	337	*
hlipka	0:8b387bed54c2	338	* It waits in the expectation of more data being sent soon (as
hlipka	0:8b387bed54c2	339	* it can send them more efficiently by combining them together).
hlipka	0:8b387bed54c2	340	* To prompt the system to send data now, call tcp_output() after
hlipka	0:8b387bed54c2	341	* calling tcp_write().
hlipka	0:8b387bed54c2	342	*
hlipka	0:8b387bed54c2	343	* @param pcb Protocol control block for the TCP connection to enqueue data for.
hlipka	0:8b387bed54c2	344	* @param arg Pointer to the data to be enqueued for sending.
hlipka	0:8b387bed54c2	345	* @param len Data length in bytes
hlipka	0:8b387bed54c2	346	* @param apiflags combination of following flags :
hlipka	0:8b387bed54c2	347	* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
hlipka	0:8b387bed54c2	348	* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
hlipka	0:8b387bed54c2	349	* @return ERR_OK if enqueued, another err_t on error
hlipka	0:8b387bed54c2	350	*/
hlipka	0:8b387bed54c2	351	err_t
hlipka	0:8b387bed54c2	352	tcp_write(struct tcp_pcb pcb, const void arg, u16_t len, u8_t apiflags)
hlipka	0:8b387bed54c2	353	{
hlipka	0:8b387bed54c2	354	struct pbuf *concat_p = NULL;
hlipka	0:8b387bed54c2	355	struct tcp_seg last_unsent = NULL, seg = NULL, prev_seg = NULL, queue = NULL;
hlipka	0:8b387bed54c2	356	u16_t pos = 0; /* position in 'arg' data */
hlipka	0:8b387bed54c2	357	u16_t queuelen;
hlipka	0:8b387bed54c2	358	u8_t optlen = 0;
hlipka	0:8b387bed54c2	359	u8_t optflags = 0;
hlipka	0:8b387bed54c2	360	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	361	u16_t oversize = 0;
hlipka	0:8b387bed54c2	362	u16_t oversize_used = 0;
hlipka	0:8b387bed54c2	363	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	364	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	365	u16_t concat_chksum = 0;
hlipka	0:8b387bed54c2	366	u8_t concat_chksum_swapped = 0;
hlipka	0:8b387bed54c2	367	u16_t concat_chksummed = 0;
hlipka	0:8b387bed54c2	368	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	369	err_t err;
hlipka	0:8b387bed54c2	370
hlipka	0:8b387bed54c2	371	#if LWIP_NETIF_TX_SINGLE_PBUF
hlipka	0:8b387bed54c2	372	/* Always copy to try to create single pbufs for TX */
hlipka	0:8b387bed54c2	373	apiflags \|= TCP_WRITE_FLAG_COPY;
hlipka	0:8b387bed54c2	374	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
hlipka	0:8b387bed54c2	375
hlipka	0:8b387bed54c2	376	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
hlipka	0:8b387bed54c2	377	(void *)pcb, arg, len, (u16_t)apiflags));
hlipka	0:8b387bed54c2	378	LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
hlipka	0:8b387bed54c2	379	arg != NULL, return ERR_ARG;);
hlipka	0:8b387bed54c2	380
hlipka	0:8b387bed54c2	381	err = tcp_write_checks(pcb, len);
hlipka	0:8b387bed54c2	382	if (err != ERR_OK) {
hlipka	0:8b387bed54c2	383	return err;
hlipka	0:8b387bed54c2	384	}
hlipka	0:8b387bed54c2	385	queuelen = pcb->snd_queuelen;
hlipka	0:8b387bed54c2	386
hlipka	0:8b387bed54c2	387	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	388	if ((pcb->flags & TF_TIMESTAMP)) {
hlipka	0:8b387bed54c2	389	optflags = TF_SEG_OPTS_TS;
hlipka	0:8b387bed54c2	390	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
hlipka	0:8b387bed54c2	391	}
hlipka	0:8b387bed54c2	392	#endif /* LWIP_TCP_TIMESTAMPS */
hlipka	0:8b387bed54c2	393
hlipka	0:8b387bed54c2	394
hlipka	0:8b387bed54c2	395	/*
hlipka	0:8b387bed54c2	396	* TCP segmentation is done in three phases with increasing complexity:
hlipka	0:8b387bed54c2	397	*
hlipka	0:8b387bed54c2	398	* 1. Copy data directly into an oversized pbuf.
hlipka	0:8b387bed54c2	399	* 2. Chain a new pbuf to the end of pcb->unsent.
hlipka	0:8b387bed54c2	400	* 3. Create new segments.
hlipka	0:8b387bed54c2	401	*
hlipka	0:8b387bed54c2	402	* We may run out of memory at any point. In that case we must
hlipka	0:8b387bed54c2	403	* return ERR_MEM and not change anything in pcb. Therefore, all
hlipka	0:8b387bed54c2	404	* changes are recorded in local variables and committed at the end
hlipka	0:8b387bed54c2	405	* of the function. Some pcb fields are maintained in local copies:
hlipka	0:8b387bed54c2	406	*
hlipka	0:8b387bed54c2	407	* queuelen = pcb->snd_queuelen
hlipka	0:8b387bed54c2	408	* oversize = pcb->unsent_oversize
hlipka	0:8b387bed54c2	409	*
hlipka	0:8b387bed54c2	410	* These variables are set consistently by the phases:
hlipka	0:8b387bed54c2	411	*
hlipka	0:8b387bed54c2	412	* seg points to the last segment tampered with.
hlipka	0:8b387bed54c2	413	*
hlipka	0:8b387bed54c2	414	* pos records progress as data is segmented.
hlipka	0:8b387bed54c2	415	*/
hlipka	0:8b387bed54c2	416
hlipka	0:8b387bed54c2	417	/* Find the tail of the unsent queue. */
hlipka	0:8b387bed54c2	418	if (pcb->unsent != NULL) {
hlipka	0:8b387bed54c2	419	u16_t space;
hlipka	0:8b387bed54c2	420	u16_t unsent_optlen;
hlipka	0:8b387bed54c2	421
hlipka	0:8b387bed54c2	422	/* @todo: this could be sped up by keeping last_unsent in the pcb */
hlipka	0:8b387bed54c2	423	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
hlipka	0:8b387bed54c2	424	last_unsent = last_unsent->next);
hlipka	0:8b387bed54c2	425
hlipka	0:8b387bed54c2	426	/* Usable space at the end of the last unsent segment */
hlipka	0:8b387bed54c2	427	unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
hlipka	0:8b387bed54c2	428	space = pcb->mss - (last_unsent->len + unsent_optlen);
hlipka	0:8b387bed54c2	429
hlipka	0:8b387bed54c2	430	/*
hlipka	0:8b387bed54c2	431	* Phase 1: Copy data directly into an oversized pbuf.
hlipka	0:8b387bed54c2	432	*
hlipka	0:8b387bed54c2	433	* The number of bytes copied is recorded in the oversize_used
hlipka	0:8b387bed54c2	434	* variable. The actual copying is done at the bottom of the
hlipka	0:8b387bed54c2	435	* function.
hlipka	0:8b387bed54c2	436	*/
hlipka	0:8b387bed54c2	437	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	438	#if TCP_OVERSIZE_DBGCHECK
hlipka	0:8b387bed54c2	439	/* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
hlipka	0:8b387bed54c2	440	LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
hlipka	0:8b387bed54c2	441	pcb->unsent_oversize == last_unsent->oversize_left);
hlipka	0:8b387bed54c2	442	#endif /* TCP_OVERSIZE_DBGCHECK */
hlipka	0:8b387bed54c2	443	oversize = pcb->unsent_oversize;
hlipka	0:8b387bed54c2	444	if (oversize > 0) {
hlipka	0:8b387bed54c2	445	LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
hlipka	0:8b387bed54c2	446	seg = last_unsent;
hlipka	0:8b387bed54c2	447	oversize_used = oversize < len ? oversize : len;
hlipka	0:8b387bed54c2	448	pos += oversize_used;
hlipka	0:8b387bed54c2	449	oversize -= oversize_used;
hlipka	0:8b387bed54c2	450	space -= oversize_used;
hlipka	0:8b387bed54c2	451	}
hlipka	0:8b387bed54c2	452	/* now we are either finished or oversize is zero */
hlipka	0:8b387bed54c2	453	LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) \|\| (pos == len));
hlipka	0:8b387bed54c2	454	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	455
hlipka	0:8b387bed54c2	456	/*
hlipka	0:8b387bed54c2	457	* Phase 2: Chain a new pbuf to the end of pcb->unsent.
hlipka	0:8b387bed54c2	458	*
hlipka	0:8b387bed54c2	459	* We don't extend segments containing SYN/FIN flags or options
hlipka	0:8b387bed54c2	460	* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
hlipka	0:8b387bed54c2	461	* the end.
hlipka	0:8b387bed54c2	462	*/
hlipka	0:8b387bed54c2	463	if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
hlipka	0:8b387bed54c2	464	u16_t seglen = space < len - pos ? space : len - pos;
hlipka	0:8b387bed54c2	465	seg = last_unsent;
hlipka	0:8b387bed54c2	466
hlipka	0:8b387bed54c2	467	/* Create a pbuf with a copy or reference to seglen bytes. We
hlipka	0:8b387bed54c2	468	* can use PBUF_RAW here since the data appears in the middle of
hlipka	0:8b387bed54c2	469	* a segment. A header will never be prepended. */
hlipka	0:8b387bed54c2	470	if (apiflags & TCP_WRITE_FLAG_COPY) {
hlipka	0:8b387bed54c2	471	/* Data is copied */
hlipka	0:8b387bed54c2	472	if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
hlipka	0:8b387bed54c2	473	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
hlipka	0:8b387bed54c2	474	("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
hlipka	0:8b387bed54c2	475	seglen));
hlipka	0:8b387bed54c2	476	goto memerr;
hlipka	0:8b387bed54c2	477	}
hlipka	0:8b387bed54c2	478	#if TCP_OVERSIZE_DBGCHECK
hlipka	0:8b387bed54c2	479	last_unsent->oversize_left = oversize;
hlipka	0:8b387bed54c2	480	#endif /* TCP_OVERSIZE_DBGCHECK */
hlipka	0:8b387bed54c2	481	TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
hlipka	0:8b387bed54c2	482	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	483	concat_chksummed += seglen;
hlipka	0:8b387bed54c2	484	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	485	} else {
hlipka	0:8b387bed54c2	486	/* Data is not copied */
hlipka	0:8b387bed54c2	487	if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
hlipka	0:8b387bed54c2	488	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
hlipka	0:8b387bed54c2	489	("tcp_write: could not allocate memory for zero-copy pbuf\n"));
hlipka	0:8b387bed54c2	490	goto memerr;
hlipka	0:8b387bed54c2	491	}
hlipka	0:8b387bed54c2	492	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	493	/* calculate the checksum of nocopy-data */
hlipka	0:8b387bed54c2	494	tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
hlipka	0:8b387bed54c2	495	&concat_chksum, &concat_chksum_swapped);
hlipka	0:8b387bed54c2	496	concat_chksummed += seglen;
hlipka	0:8b387bed54c2	497	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	498	/* reference the non-volatile payload data */
hlipka	0:8b387bed54c2	499	concat_p->payload = (u8_t*)arg + pos;
hlipka	0:8b387bed54c2	500	}
hlipka	0:8b387bed54c2	501
hlipka	0:8b387bed54c2	502	pos += seglen;
hlipka	0:8b387bed54c2	503	queuelen += pbuf_clen(concat_p);
hlipka	0:8b387bed54c2	504	}
hlipka	0:8b387bed54c2	505	} else {
hlipka	0:8b387bed54c2	506	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	507	LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
hlipka	0:8b387bed54c2	508	pcb->unsent_oversize == 0);
hlipka	0:8b387bed54c2	509	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	510	}
hlipka	0:8b387bed54c2	511
hlipka	0:8b387bed54c2	512	/*
hlipka	0:8b387bed54c2	513	* Phase 3: Create new segments.
hlipka	0:8b387bed54c2	514	*
hlipka	0:8b387bed54c2	515	* The new segments are chained together in the local 'queue'
hlipka	0:8b387bed54c2	516	* variable, ready to be appended to pcb->unsent.
hlipka	0:8b387bed54c2	517	*/
hlipka	0:8b387bed54c2	518	while (pos < len) {
hlipka	0:8b387bed54c2	519	struct pbuf *p;
hlipka	0:8b387bed54c2	520	u16_t left = len - pos;
hlipka	0:8b387bed54c2	521	u16_t max_len = pcb->mss - optlen;
hlipka	0:8b387bed54c2	522	u16_t seglen = left > max_len ? max_len : left;
hlipka	0:8b387bed54c2	523	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	524	u16_t chksum = 0;
hlipka	0:8b387bed54c2	525	u8_t chksum_swapped = 0;
hlipka	0:8b387bed54c2	526	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	527
hlipka	0:8b387bed54c2	528	if (apiflags & TCP_WRITE_FLAG_COPY) {
hlipka	0:8b387bed54c2	529	/* If copy is set, memory should be allocated and data copied
hlipka	0:8b387bed54c2	530	* into pbuf */
hlipka	0:8b387bed54c2	531	if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
hlipka	0:8b387bed54c2	532	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
hlipka	0:8b387bed54c2	533	goto memerr;
hlipka	0:8b387bed54c2	534	}
hlipka	0:8b387bed54c2	535	LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
hlipka	0:8b387bed54c2	536	(p->len >= seglen));
hlipka	0:8b387bed54c2	537	TCP_DATA_COPY2((char )p->payload + optlen, (u8_t)arg + pos, seglen, &chksum, &chksum_swapped);
hlipka	0:8b387bed54c2	538	} else {
hlipka	0:8b387bed54c2	539	/* Copy is not set: First allocate a pbuf for holding the data.
hlipka	0:8b387bed54c2	540	* Since the referenced data is available at least until it is
hlipka	0:8b387bed54c2	541	* sent out on the link (as it has to be ACKed by the remote
hlipka	0:8b387bed54c2	542	* party) we can safely use PBUF_ROM instead of PBUF_REF here.
hlipka	0:8b387bed54c2	543	*/
hlipka	0:8b387bed54c2	544	struct pbuf *p2;
hlipka	0:8b387bed54c2	545	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	546	LWIP_ASSERT("oversize == 0", oversize == 0);
hlipka	0:8b387bed54c2	547	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	548	if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
hlipka	0:8b387bed54c2	549	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
hlipka	0:8b387bed54c2	550	goto memerr;
hlipka	0:8b387bed54c2	551	}
hlipka	0:8b387bed54c2	552	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	553	/* calculate the checksum of nocopy-data */
hlipka	0:8b387bed54c2	554	chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
hlipka	0:8b387bed54c2	555	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	556	/* reference the non-volatile payload data */
hlipka	0:8b387bed54c2	557	p2->payload = (u8_t*)arg + pos;
hlipka	0:8b387bed54c2	558
hlipka	0:8b387bed54c2	559	/* Second, allocate a pbuf for the headers. */
hlipka	0:8b387bed54c2	560	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
hlipka	0:8b387bed54c2	561	/* If allocation fails, we have to deallocate the data pbuf as
hlipka	0:8b387bed54c2	562	* well. */
hlipka	0:8b387bed54c2	563	pbuf_free(p2);
hlipka	0:8b387bed54c2	564	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for header pbuf\n"));
hlipka	0:8b387bed54c2	565	goto memerr;
hlipka	0:8b387bed54c2	566	}
hlipka	0:8b387bed54c2	567	/* Concatenate the headers and data pbufs together. */
hlipka	0:8b387bed54c2	568	pbuf_cat(p/header/, p2/data/);
hlipka	0:8b387bed54c2	569	}
hlipka	0:8b387bed54c2	570
hlipka	0:8b387bed54c2	571	queuelen += pbuf_clen(p);
hlipka	0:8b387bed54c2	572
hlipka	0:8b387bed54c2	573	/* Now that there are more segments queued, we check again if the
hlipka	0:8b387bed54c2	574	* length of the queue exceeds the configured maximum or
hlipka	0:8b387bed54c2	575	* overflows. */
hlipka	0:8b387bed54c2	576	if ((queuelen > TCP_SND_QUEUELEN) \|\| (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
hlipka	0:8b387bed54c2	577	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
hlipka	0:8b387bed54c2	578	pbuf_free(p);
hlipka	0:8b387bed54c2	579	goto memerr;
hlipka	0:8b387bed54c2	580	}
hlipka	0:8b387bed54c2	581
hlipka	0:8b387bed54c2	582	if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
hlipka	0:8b387bed54c2	583	goto memerr;
hlipka	0:8b387bed54c2	584	}
hlipka	0:8b387bed54c2	585	#if TCP_OVERSIZE_DBGCHECK
hlipka	0:8b387bed54c2	586	seg->oversize_left = oversize;
hlipka	0:8b387bed54c2	587	#endif /* TCP_OVERSIZE_DBGCHECK */
hlipka	0:8b387bed54c2	588	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	589	seg->chksum = chksum;
hlipka	0:8b387bed54c2	590	seg->chksum_swapped = chksum_swapped;
hlipka	0:8b387bed54c2	591	seg->flags \|= TF_SEG_DATA_CHECKSUMMED;
hlipka	0:8b387bed54c2	592	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	593	/* Fix dataptr for the nocopy case */
hlipka	0:8b387bed54c2	594	if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
hlipka	0:8b387bed54c2	595	seg->dataptr = (u8_t*)arg + pos;
hlipka	0:8b387bed54c2	596	}
hlipka	0:8b387bed54c2	597
hlipka	0:8b387bed54c2	598	/* first segment of to-be-queued data? */
hlipka	0:8b387bed54c2	599	if (queue == NULL) {
hlipka	0:8b387bed54c2	600	queue = seg;
hlipka	0:8b387bed54c2	601	} else {
hlipka	0:8b387bed54c2	602	/* Attach the segment to the end of the queued segments */
hlipka	0:8b387bed54c2	603	LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
hlipka	0:8b387bed54c2	604	prev_seg->next = seg;
hlipka	0:8b387bed54c2	605	}
hlipka	0:8b387bed54c2	606	/* remember last segment of to-be-queued data for next iteration */
hlipka	0:8b387bed54c2	607	prev_seg = seg;
hlipka	0:8b387bed54c2	608
hlipka	0:8b387bed54c2	609	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
hlipka	0:8b387bed54c2	610	ntohl(seg->tcphdr->seqno),
hlipka	0:8b387bed54c2	611	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
hlipka	0:8b387bed54c2	612
hlipka	0:8b387bed54c2	613	pos += seglen;
hlipka	0:8b387bed54c2	614	}
hlipka	0:8b387bed54c2	615
hlipka	0:8b387bed54c2	616	/*
hlipka	0:8b387bed54c2	617	* All three segmentation phases were successful. We can commit the
hlipka	0:8b387bed54c2	618	* transaction.
hlipka	0:8b387bed54c2	619	*/
hlipka	0:8b387bed54c2	620
hlipka	0:8b387bed54c2	621	/*
hlipka	0:8b387bed54c2	622	* Phase 1: If data has been added to the preallocated tail of
hlipka	0:8b387bed54c2	623	* last_unsent, we update the length fields of the pbuf chain.
hlipka	0:8b387bed54c2	624	*/
hlipka	0:8b387bed54c2	625	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	626	if (oversize_used > 0) {
hlipka	0:8b387bed54c2	627	struct pbuf *p;
hlipka	0:8b387bed54c2	628	/* Bump tot_len of whole chain, len of tail */
hlipka	0:8b387bed54c2	629	for (p = last_unsent->p; p; p = p->next) {
hlipka	0:8b387bed54c2	630	p->tot_len += oversize_used;
hlipka	0:8b387bed54c2	631	if (p->next == NULL) {
hlipka	0:8b387bed54c2	632	TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
hlipka	0:8b387bed54c2	633	p->len += oversize_used;
hlipka	0:8b387bed54c2	634	}
hlipka	0:8b387bed54c2	635	}
hlipka	0:8b387bed54c2	636	last_unsent->len += oversize_used;
hlipka	0:8b387bed54c2	637	#if TCP_OVERSIZE_DBGCHECK
hlipka	0:8b387bed54c2	638	last_unsent->oversize_left -= oversize_used;
hlipka	0:8b387bed54c2	639	#endif /* TCP_OVERSIZE_DBGCHECK */
hlipka	0:8b387bed54c2	640	}
hlipka	0:8b387bed54c2	641	pcb->unsent_oversize = oversize;
hlipka	0:8b387bed54c2	642	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	643
hlipka	0:8b387bed54c2	644	/*
hlipka	0:8b387bed54c2	645	* Phase 2: concat_p can be concatenated onto last_unsent->p
hlipka	0:8b387bed54c2	646	*/
hlipka	0:8b387bed54c2	647	if (concat_p != NULL) {
hlipka	0:8b387bed54c2	648	LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
hlipka	0:8b387bed54c2	649	(last_unsent != NULL));
hlipka	0:8b387bed54c2	650	pbuf_cat(last_unsent->p, concat_p);
hlipka	0:8b387bed54c2	651	last_unsent->len += concat_p->tot_len;
hlipka	0:8b387bed54c2	652	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	653	if (concat_chksummed) {
hlipka	0:8b387bed54c2	654	tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
hlipka	0:8b387bed54c2	655	&last_unsent->chksum_swapped);
hlipka	0:8b387bed54c2	656	last_unsent->flags \|= TF_SEG_DATA_CHECKSUMMED;
hlipka	0:8b387bed54c2	657	}
hlipka	0:8b387bed54c2	658	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	659	}
hlipka	0:8b387bed54c2	660
hlipka	0:8b387bed54c2	661	/*
hlipka	0:8b387bed54c2	662	* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
hlipka	0:8b387bed54c2	663	* is harmless
hlipka	0:8b387bed54c2	664	*/
hlipka	0:8b387bed54c2	665	if (last_unsent == NULL) {
hlipka	0:8b387bed54c2	666	pcb->unsent = queue;
hlipka	0:8b387bed54c2	667	} else {
hlipka	0:8b387bed54c2	668	last_unsent->next = queue;
hlipka	0:8b387bed54c2	669	}
hlipka	0:8b387bed54c2	670
hlipka	0:8b387bed54c2	671	/*
hlipka	0:8b387bed54c2	672	* Finally update the pcb state.
hlipka	0:8b387bed54c2	673	*/
hlipka	0:8b387bed54c2	674	pcb->snd_lbb += len;
hlipka	0:8b387bed54c2	675	pcb->snd_buf -= len;
hlipka	0:8b387bed54c2	676	pcb->snd_queuelen = queuelen;
hlipka	0:8b387bed54c2	677
hlipka	0:8b387bed54c2	678	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
hlipka	0:8b387bed54c2	679	pcb->snd_queuelen));
hlipka	0:8b387bed54c2	680	if (pcb->snd_queuelen != 0) {
hlipka	0:8b387bed54c2	681	LWIP_ASSERT("tcp_write: valid queue length",
hlipka	0:8b387bed54c2	682	pcb->unacked != NULL \|\| pcb->unsent != NULL);
hlipka	0:8b387bed54c2	683	}
hlipka	0:8b387bed54c2	684
hlipka	0:8b387bed54c2	685	/* Set the PSH flag in the last segment that we enqueued. */
hlipka	0:8b387bed54c2	686	if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
hlipka	0:8b387bed54c2	687	TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
hlipka	0:8b387bed54c2	688	}
hlipka	0:8b387bed54c2	689
hlipka	0:8b387bed54c2	690	return ERR_OK;
hlipka	0:8b387bed54c2	691	memerr:
hlipka	0:8b387bed54c2	692	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	693	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	694
hlipka	0:8b387bed54c2	695	if (concat_p != NULL) {
hlipka	0:8b387bed54c2	696	pbuf_free(concat_p);
hlipka	0:8b387bed54c2	697	}
hlipka	0:8b387bed54c2	698	if (queue != NULL) {
hlipka	0:8b387bed54c2	699	tcp_segs_free(queue);
hlipka	0:8b387bed54c2	700	}
hlipka	0:8b387bed54c2	701	if (pcb->snd_queuelen != 0) {
hlipka	0:8b387bed54c2	702	LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL \|\|
hlipka	0:8b387bed54c2	703	pcb->unsent != NULL);
hlipka	0:8b387bed54c2	704	}
hlipka	0:8b387bed54c2	705	LWIP_DEBUGF(TCP_QLEN_DEBUG \| LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
hlipka	0:8b387bed54c2	706	return ERR_MEM;
hlipka	0:8b387bed54c2	707	}
hlipka	0:8b387bed54c2	708
hlipka	0:8b387bed54c2	709	/**
hlipka	0:8b387bed54c2	710	* Enqueue TCP options for transmission.
hlipka	0:8b387bed54c2	711	*
hlipka	0:8b387bed54c2	712	* Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
hlipka	0:8b387bed54c2	713	*
hlipka	0:8b387bed54c2	714	* @param pcb Protocol control block for the TCP connection.
hlipka	0:8b387bed54c2	715	* @param flags TCP header flags to set in the outgoing segment.
hlipka	0:8b387bed54c2	716	* @param optdata pointer to TCP options, or NULL.
hlipka	0:8b387bed54c2	717	* @param optlen length of TCP options in bytes.
hlipka	0:8b387bed54c2	718	*/
hlipka	0:8b387bed54c2	719	err_t
hlipka	0:8b387bed54c2	720	tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
hlipka	0:8b387bed54c2	721	{
hlipka	0:8b387bed54c2	722	struct pbuf *p;
hlipka	0:8b387bed54c2	723	struct tcp_seg *seg;
hlipka	0:8b387bed54c2	724	u8_t optflags = 0;
hlipka	0:8b387bed54c2	725	u8_t optlen = 0;
hlipka	0:8b387bed54c2	726
hlipka	0:8b387bed54c2	727	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
hlipka	0:8b387bed54c2	728
hlipka	0:8b387bed54c2	729	LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
hlipka	0:8b387bed54c2	730	(flags & (TCP_SYN \| TCP_FIN)) != 0);
hlipka	0:8b387bed54c2	731
hlipka	0:8b387bed54c2	732	/* check for configured max queuelen and possible overflow */
hlipka	0:8b387bed54c2	733	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
hlipka	0:8b387bed54c2	734	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
hlipka	0:8b387bed54c2	735	pcb->snd_queuelen, TCP_SND_QUEUELEN));
hlipka	0:8b387bed54c2	736	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	737	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	738	return ERR_MEM;
hlipka	0:8b387bed54c2	739	}
hlipka	0:8b387bed54c2	740
hlipka	0:8b387bed54c2	741	if (flags & TCP_SYN) {
hlipka	0:8b387bed54c2	742	optflags = TF_SEG_OPTS_MSS;
hlipka	0:8b387bed54c2	743	}
hlipka	0:8b387bed54c2	744	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	745	if ((pcb->flags & TF_TIMESTAMP)) {
hlipka	0:8b387bed54c2	746	optflags \|= TF_SEG_OPTS_TS;
hlipka	0:8b387bed54c2	747	}
hlipka	0:8b387bed54c2	748	#endif /* LWIP_TCP_TIMESTAMPS */
hlipka	0:8b387bed54c2	749	optlen = LWIP_TCP_OPT_LENGTH(optflags);
hlipka	0:8b387bed54c2	750
hlipka	0:8b387bed54c2	751	/* tcp_enqueue_flags is always called with either SYN or FIN in flags.
hlipka	0:8b387bed54c2	752	* We need one available snd_buf byte to do that.
hlipka	0:8b387bed54c2	753	* This means we can't send FIN while snd_buf==0. A better fix would be to
hlipka	0:8b387bed54c2	754	* not include SYN and FIN sequence numbers in the snd_buf count. */
hlipka	0:8b387bed54c2	755	if (pcb->snd_buf == 0) {
hlipka	0:8b387bed54c2	756	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: no send buffer available\n"));
hlipka	0:8b387bed54c2	757	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	758	return ERR_MEM;
hlipka	0:8b387bed54c2	759	}
hlipka	0:8b387bed54c2	760
hlipka	0:8b387bed54c2	761	/* Allocate pbuf with room for TCP header + options */
hlipka	0:8b387bed54c2	762	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
hlipka	0:8b387bed54c2	763	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	764	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	765	return ERR_MEM;
hlipka	0:8b387bed54c2	766	}
hlipka	0:8b387bed54c2	767	LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
hlipka	0:8b387bed54c2	768	(p->len >= optlen));
hlipka	0:8b387bed54c2	769
hlipka	0:8b387bed54c2	770	/* Allocate memory for tcp_seg, and fill in fields. */
hlipka	0:8b387bed54c2	771	if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
hlipka	0:8b387bed54c2	772	pcb->flags \|= TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	773	TCP_STATS_INC(tcp.memerr);
hlipka	0:8b387bed54c2	774	return ERR_MEM;
hlipka	0:8b387bed54c2	775	}
hlipka	0:8b387bed54c2	776	LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
hlipka	0:8b387bed54c2	777
hlipka	0:8b387bed54c2	778	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE,
hlipka	0:8b387bed54c2	779	("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
hlipka	0:8b387bed54c2	780	ntohl(seg->tcphdr->seqno),
hlipka	0:8b387bed54c2	781	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
hlipka	0:8b387bed54c2	782	(u16_t)flags));
hlipka	0:8b387bed54c2	783
hlipka	0:8b387bed54c2	784	/* Now append seg to pcb->unsent queue */
hlipka	0:8b387bed54c2	785	if (pcb->unsent == NULL) {
hlipka	0:8b387bed54c2	786	pcb->unsent = seg;
hlipka	0:8b387bed54c2	787	} else {
hlipka	0:8b387bed54c2	788	struct tcp_seg *useg;
hlipka	0:8b387bed54c2	789	for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
hlipka	0:8b387bed54c2	790	useg->next = seg;
hlipka	0:8b387bed54c2	791	}
hlipka	0:8b387bed54c2	792	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	793	/* The new unsent tail has no space */
hlipka	0:8b387bed54c2	794	pcb->unsent_oversize = 0;
hlipka	0:8b387bed54c2	795	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	796
hlipka	0:8b387bed54c2	797	/* SYN and FIN bump the sequence number */
hlipka	0:8b387bed54c2	798	if ((flags & TCP_SYN) \|\| (flags & TCP_FIN)) {
hlipka	0:8b387bed54c2	799	pcb->snd_lbb++;
hlipka	0:8b387bed54c2	800	/* optlen does not influence snd_buf */
hlipka	0:8b387bed54c2	801	pcb->snd_buf--;
hlipka	0:8b387bed54c2	802	}
hlipka	0:8b387bed54c2	803	if (flags & TCP_FIN) {
hlipka	0:8b387bed54c2	804	pcb->flags \|= TF_FIN;
hlipka	0:8b387bed54c2	805	}
hlipka	0:8b387bed54c2	806
hlipka	0:8b387bed54c2	807	/* update number of segments on the queues */
hlipka	0:8b387bed54c2	808	pcb->snd_queuelen += pbuf_clen(seg->p);
hlipka	0:8b387bed54c2	809	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
hlipka	0:8b387bed54c2	810	if (pcb->snd_queuelen != 0) {
hlipka	0:8b387bed54c2	811	LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
hlipka	0:8b387bed54c2	812	pcb->unacked != NULL \|\| pcb->unsent != NULL);
hlipka	0:8b387bed54c2	813	}
hlipka	0:8b387bed54c2	814
hlipka	0:8b387bed54c2	815	return ERR_OK;
hlipka	0:8b387bed54c2	816	}
hlipka	0:8b387bed54c2	817
hlipka	0:8b387bed54c2	818
hlipka	0:8b387bed54c2	819	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	820	/* Build a timestamp option (12 bytes long) at the specified options pointer)
hlipka	0:8b387bed54c2	821	*
hlipka	0:8b387bed54c2	822	* @param pcb tcp_pcb
hlipka	0:8b387bed54c2	823	* @param opts option pointer where to store the timestamp option
hlipka	0:8b387bed54c2	824	*/
hlipka	0:8b387bed54c2	825	static void
hlipka	0:8b387bed54c2	826	tcp_build_timestamp_option(struct tcp_pcb pcb, u32_t opts)
hlipka	0:8b387bed54c2	827	{
hlipka	0:8b387bed54c2	828	/* Pad with two NOP options to make everything nicely aligned */
hlipka	0:8b387bed54c2	829	opts[0] = PP_HTONL(0x0101080A);
hlipka	0:8b387bed54c2	830	opts[1] = htonl(sys_now());
hlipka	0:8b387bed54c2	831	opts[2] = htonl(pcb->ts_recent);
hlipka	0:8b387bed54c2	832	}
hlipka	0:8b387bed54c2	833	#endif
hlipka	0:8b387bed54c2	834
hlipka	0:8b387bed54c2	835	/** Send an ACK without data.
hlipka	0:8b387bed54c2	836	*
hlipka	0:8b387bed54c2	837	* @param pcb Protocol control block for the TCP connection to send the ACK
hlipka	0:8b387bed54c2	838	*/
hlipka	0:8b387bed54c2	839	err_t
hlipka	0:8b387bed54c2	840	tcp_send_empty_ack(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	841	{
hlipka	0:8b387bed54c2	842	struct pbuf *p;
hlipka	0:8b387bed54c2	843	struct tcp_hdr *tcphdr;
hlipka	0:8b387bed54c2	844	u8_t optlen = 0;
hlipka	0:8b387bed54c2	845
hlipka	0:8b387bed54c2	846	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	847	if (pcb->flags & TF_TIMESTAMP) {
hlipka	0:8b387bed54c2	848	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
hlipka	0:8b387bed54c2	849	}
hlipka	0:8b387bed54c2	850	#endif
hlipka	0:8b387bed54c2	851
hlipka	0:8b387bed54c2	852	p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
hlipka	0:8b387bed54c2	853	if (p == NULL) {
hlipka	0:8b387bed54c2	854	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
hlipka	0:8b387bed54c2	855	return ERR_BUF;
hlipka	0:8b387bed54c2	856	}
hlipka	0:8b387bed54c2	857	tcphdr = (struct tcp_hdr *)p->payload;
hlipka	0:8b387bed54c2	858	LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
hlipka	0:8b387bed54c2	859	("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
hlipka	0:8b387bed54c2	860	/* remove ACK flags from the PCB, as we send an empty ACK now */
hlipka	0:8b387bed54c2	861	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
hlipka	0:8b387bed54c2	862
hlipka	0:8b387bed54c2	863	/* NB. MSS option is only sent on SYNs, so ignore it here */
hlipka	0:8b387bed54c2	864	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	865	pcb->ts_lastacksent = pcb->rcv_nxt;
hlipka	0:8b387bed54c2	866
hlipka	0:8b387bed54c2	867	if (pcb->flags & TF_TIMESTAMP) {
hlipka	0:8b387bed54c2	868	tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
hlipka	0:8b387bed54c2	869	}
hlipka	0:8b387bed54c2	870	#endif
hlipka	0:8b387bed54c2	871
hlipka	0:8b387bed54c2	872	#if CHECKSUM_GEN_TCP
hlipka	0:8b387bed54c2	873	tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
hlipka	0:8b387bed54c2	874	IP_PROTO_TCP, p->tot_len);
hlipka	0:8b387bed54c2	875	#endif
hlipka	0:8b387bed54c2	876	#if LWIP_NETIF_HWADDRHINT
hlipka	0:8b387bed54c2	877	ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
hlipka	0:8b387bed54c2	878	IP_PROTO_TCP, &(pcb->addr_hint));
hlipka	0:8b387bed54c2	879	#else /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	880	ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
hlipka	0:8b387bed54c2	881	IP_PROTO_TCP);
hlipka	0:8b387bed54c2	882	#endif /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	883	pbuf_free(p);
hlipka	0:8b387bed54c2	884
hlipka	0:8b387bed54c2	885	return ERR_OK;
hlipka	0:8b387bed54c2	886	}
hlipka	0:8b387bed54c2	887
hlipka	0:8b387bed54c2	888	/**
hlipka	0:8b387bed54c2	889	* Find out what we can send and send it
hlipka	0:8b387bed54c2	890	*
hlipka	0:8b387bed54c2	891	* @param pcb Protocol control block for the TCP connection to send data
hlipka	0:8b387bed54c2	892	* @return ERR_OK if data has been sent or nothing to send
hlipka	0:8b387bed54c2	893	* another err_t on error
hlipka	0:8b387bed54c2	894	*/
hlipka	0:8b387bed54c2	895	err_t
hlipka	0:8b387bed54c2	896	tcp_output(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	897	{
hlipka	0:8b387bed54c2	898	struct tcp_seg seg, useg;
hlipka	0:8b387bed54c2	899	u32_t wnd, snd_nxt;
hlipka	0:8b387bed54c2	900	#if TCP_CWND_DEBUG
hlipka	0:8b387bed54c2	901	s16_t i = 0;
hlipka	0:8b387bed54c2	902	#endif /* TCP_CWND_DEBUG */
hlipka	0:8b387bed54c2	903
hlipka	0:8b387bed54c2	904	/* First, check if we are invoked by the TCP input processing
hlipka	0:8b387bed54c2	905	code. If so, we do not output anything. Instead, we rely on the
hlipka	0:8b387bed54c2	906	input processing code to call us when input processing is done
hlipka	0:8b387bed54c2	907	with. */
hlipka	0:8b387bed54c2	908	if (tcp_input_pcb == pcb) {
hlipka	0:8b387bed54c2	909	return ERR_OK;
hlipka	0:8b387bed54c2	910	}
hlipka	0:8b387bed54c2	911
hlipka	0:8b387bed54c2	912	wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
hlipka	0:8b387bed54c2	913
hlipka	0:8b387bed54c2	914	seg = pcb->unsent;
hlipka	0:8b387bed54c2	915
hlipka	0:8b387bed54c2	916	/* If the TF_ACK_NOW flag is set and no data will be sent (either
hlipka	0:8b387bed54c2	917	* because the ->unsent queue is empty or because the window does
hlipka	0:8b387bed54c2	918	* not allow it), construct an empty ACK segment and send it.
hlipka	0:8b387bed54c2	919	*
hlipka	0:8b387bed54c2	920	* If data is to be sent, we will just piggyback the ACK (see below).
hlipka	0:8b387bed54c2	921	*/
hlipka	0:8b387bed54c2	922	if (pcb->flags & TF_ACK_NOW &&
hlipka	0:8b387bed54c2	923	(seg == NULL \|\|
hlipka	0:8b387bed54c2	924	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
hlipka	0:8b387bed54c2	925	return tcp_send_empty_ack(pcb);
hlipka	0:8b387bed54c2	926	}
hlipka	0:8b387bed54c2	927
hlipka	0:8b387bed54c2	928	/* useg should point to last segment on unacked queue */
hlipka	0:8b387bed54c2	929	useg = pcb->unacked;
hlipka	0:8b387bed54c2	930	if (useg != NULL) {
hlipka	0:8b387bed54c2	931	for (; useg->next != NULL; useg = useg->next);
hlipka	0:8b387bed54c2	932	}
hlipka	0:8b387bed54c2	933
hlipka	0:8b387bed54c2	934	#if TCP_OUTPUT_DEBUG
hlipka	0:8b387bed54c2	935	if (seg == NULL) {
hlipka	0:8b387bed54c2	936	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
hlipka	0:8b387bed54c2	937	(void*)pcb->unsent));
hlipka	0:8b387bed54c2	938	}
hlipka	0:8b387bed54c2	939	#endif /* TCP_OUTPUT_DEBUG */
hlipka	0:8b387bed54c2	940	#if TCP_CWND_DEBUG
hlipka	0:8b387bed54c2	941	if (seg == NULL) {
hlipka	0:8b387bed54c2	942	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
hlipka	0:8b387bed54c2	943	", cwnd %"U16_F", wnd %"U32_F
hlipka	0:8b387bed54c2	944	", seg == NULL, ack %"U32_F"\n",
hlipka	0:8b387bed54c2	945	pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
hlipka	0:8b387bed54c2	946	} else {
hlipka	0:8b387bed54c2	947	LWIP_DEBUGF(TCP_CWND_DEBUG,
hlipka	0:8b387bed54c2	948	("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
hlipka	0:8b387bed54c2	949	", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
hlipka	0:8b387bed54c2	950	pcb->snd_wnd, pcb->cwnd, wnd,
hlipka	0:8b387bed54c2	951	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
hlipka	0:8b387bed54c2	952	ntohl(seg->tcphdr->seqno), pcb->lastack));
hlipka	0:8b387bed54c2	953	}
hlipka	0:8b387bed54c2	954	#endif /* TCP_CWND_DEBUG */
hlipka	0:8b387bed54c2	955	/* data available and window allows it to be sent? */
hlipka	0:8b387bed54c2	956	while (seg != NULL &&
hlipka	0:8b387bed54c2	957	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
hlipka	0:8b387bed54c2	958	LWIP_ASSERT("RST not expected here!",
hlipka	0:8b387bed54c2	959	(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
hlipka	0:8b387bed54c2	960	/* Stop sending if the nagle algorithm would prevent it
hlipka	0:8b387bed54c2	961	* Don't stop:
hlipka	0:8b387bed54c2	962	* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
hlipka	0:8b387bed54c2	963	* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
hlipka	0:8b387bed54c2	964	* either seg->next != NULL or pcb->unacked == NULL;
hlipka	0:8b387bed54c2	965	* RST is no sent using tcp_write/tcp_output.
hlipka	0:8b387bed54c2	966	*/
hlipka	0:8b387bed54c2	967	if((tcp_do_output_nagle(pcb) == 0) &&
hlipka	0:8b387bed54c2	968	((pcb->flags & (TF_NAGLEMEMERR \| TF_FIN)) == 0)){
hlipka	0:8b387bed54c2	969	break;
hlipka	0:8b387bed54c2	970	}
hlipka	0:8b387bed54c2	971	#if TCP_CWND_DEBUG
hlipka	0:8b387bed54c2	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",
hlipka	0:8b387bed54c2	973	pcb->snd_wnd, pcb->cwnd, wnd,
hlipka	0:8b387bed54c2	974	ntohl(seg->tcphdr->seqno) + seg->len -
hlipka	0:8b387bed54c2	975	pcb->lastack,
hlipka	0:8b387bed54c2	976	ntohl(seg->tcphdr->seqno), pcb->lastack, i));
hlipka	0:8b387bed54c2	977	++i;
hlipka	0:8b387bed54c2	978	#endif /* TCP_CWND_DEBUG */
hlipka	0:8b387bed54c2	979
hlipka	0:8b387bed54c2	980	pcb->unsent = seg->next;
hlipka	0:8b387bed54c2	981
hlipka	0:8b387bed54c2	982	if (pcb->state != SYN_SENT) {
hlipka	0:8b387bed54c2	983	TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
hlipka	0:8b387bed54c2	984	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
hlipka	0:8b387bed54c2	985	}
hlipka	0:8b387bed54c2	986
hlipka	0:8b387bed54c2	987	tcp_output_segment(seg, pcb);
hlipka	0:8b387bed54c2	988
hlipka	0:8b387bed54c2	989	snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
hlipka	0:8b387bed54c2	990
hlipka	0:8b387bed54c2	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
hlipka	0:8b387bed54c2	992	pcb->snd_nxt, ntohl(seg->tcphdr->seqno), TCP_TCPLEN(seg), snd_nxt));
hlipka	0:8b387bed54c2	993
hlipka	0:8b387bed54c2	994	if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
hlipka	0:8b387bed54c2	995	pcb->snd_nxt = snd_nxt;
hlipka	0:8b387bed54c2	996	}
hlipka	0:8b387bed54c2	997	/* put segment on unacknowledged list if length > 0 */
hlipka	0:8b387bed54c2	998	if (TCP_TCPLEN(seg) > 0) {
hlipka	0:8b387bed54c2	999	seg->next = NULL;
hlipka	0:8b387bed54c2	1000	/* unacked list is empty? */
hlipka	0:8b387bed54c2	1001	if (pcb->unacked == NULL) {
hlipka	0:8b387bed54c2	1002	pcb->unacked = seg;
hlipka	0:8b387bed54c2	1003	useg = seg;
hlipka	0:8b387bed54c2	1004	/* unacked list is not empty? */
hlipka	0:8b387bed54c2	1005	} else {
hlipka	0:8b387bed54c2	1006	/* In the case of fast retransmit, the packet should not go to the tail
hlipka	0:8b387bed54c2	1007	* of the unacked queue, but rather somewhere before it. We need to check for
hlipka	0:8b387bed54c2	1008	* this case. -STJ Jul 27, 2004 */
hlipka	0:8b387bed54c2	1009	if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
hlipka	0:8b387bed54c2	1010	/* add segment to before tail of unacked list, keeping the list sorted */
hlipka	0:8b387bed54c2	1011	struct tcp_seg **cur_seg = &(pcb->unacked);
hlipka	0:8b387bed54c2	1012	while (*cur_seg &&
hlipka	0:8b387bed54c2	1013	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
hlipka	0:8b387bed54c2	1014	cur_seg = &((*cur_seg)->next );
hlipka	0:8b387bed54c2	1015	}
hlipka	0:8b387bed54c2	1016	seg->next = (*cur_seg);
hlipka	0:8b387bed54c2	1017	(*cur_seg) = seg;
hlipka	0:8b387bed54c2	1018	} else {
hlipka	0:8b387bed54c2	1019	/* add segment to tail of unacked list */
hlipka	0:8b387bed54c2	1020	useg->next = seg;
hlipka	0:8b387bed54c2	1021	useg = useg->next;
hlipka	0:8b387bed54c2	1022	}
hlipka	0:8b387bed54c2	1023	}
hlipka	0:8b387bed54c2	1024	/* do not queue empty segments on the unacked list */
hlipka	0:8b387bed54c2	1025	} else {
hlipka	0:8b387bed54c2	1026	tcp_seg_free(seg);
hlipka	0:8b387bed54c2	1027	}
hlipka	0:8b387bed54c2	1028	seg = pcb->unsent;
hlipka	0:8b387bed54c2	1029	}
hlipka	0:8b387bed54c2	1030	#if TCP_OVERSIZE
hlipka	0:8b387bed54c2	1031	if (pcb->unsent == NULL) {
hlipka	0:8b387bed54c2	1032	/* last unsent has been removed, reset unsent_oversize */
hlipka	0:8b387bed54c2	1033	pcb->unsent_oversize = 0;
hlipka	0:8b387bed54c2	1034	}
hlipka	0:8b387bed54c2	1035	#endif /* TCP_OVERSIZE */
hlipka	0:8b387bed54c2	1036
hlipka	0:8b387bed54c2	1037	if (seg != NULL && pcb->persist_backoff == 0 &&
hlipka	0:8b387bed54c2	1038	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
hlipka	0:8b387bed54c2	1039	/* prepare for persist timer */
hlipka	0:8b387bed54c2	1040	pcb->persist_cnt = 0;
hlipka	0:8b387bed54c2	1041	pcb->persist_backoff = 1;
hlipka	0:8b387bed54c2	1042	}
hlipka	0:8b387bed54c2	1043
hlipka	0:8b387bed54c2	1044	pcb->flags &= ~TF_NAGLEMEMERR;
hlipka	0:8b387bed54c2	1045	return ERR_OK;
hlipka	0:8b387bed54c2	1046	}
hlipka	0:8b387bed54c2	1047
hlipka	0:8b387bed54c2	1048	/**
hlipka	0:8b387bed54c2	1049	* Called by tcp_output() to actually send a TCP segment over IP.
hlipka	0:8b387bed54c2	1050	*
hlipka	0:8b387bed54c2	1051	* @param seg the tcp_seg to send
hlipka	0:8b387bed54c2	1052	* @param pcb the tcp_pcb for the TCP connection used to send the segment
hlipka	0:8b387bed54c2	1053	*/
hlipka	0:8b387bed54c2	1054	static void
hlipka	0:8b387bed54c2	1055	tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb)
hlipka	0:8b387bed54c2	1056	{
hlipka	0:8b387bed54c2	1057	u16_t len;
hlipka	0:8b387bed54c2	1058	struct netif *netif;
hlipka	0:8b387bed54c2	1059	u32_t *opts;
hlipka	0:8b387bed54c2	1060
hlipka	0:8b387bed54c2	1061	/** @bug Exclude retransmitted segments from this count. */
hlipka	0:8b387bed54c2	1062	snmp_inc_tcpoutsegs();
hlipka	0:8b387bed54c2	1063
hlipka	0:8b387bed54c2	1064	/* The TCP header has already been constructed, but the ackno and
hlipka	0:8b387bed54c2	1065	wnd fields remain. */
hlipka	0:8b387bed54c2	1066	seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
hlipka	0:8b387bed54c2	1067
hlipka	0:8b387bed54c2	1068	/* advertise our receive window size in this TCP segment */
hlipka	0:8b387bed54c2	1069	seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
hlipka	0:8b387bed54c2	1070
hlipka	0:8b387bed54c2	1071	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
hlipka	0:8b387bed54c2	1072
hlipka	0:8b387bed54c2	1073	/* Add any requested options. NB MSS option is only set on SYN
hlipka	0:8b387bed54c2	1074	packets, so ignore it here */
hlipka	0:8b387bed54c2	1075	LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)(seg->tcphdr + 1) % 4) == 0);
hlipka	0:8b387bed54c2	1076	opts = (u32_t )(void )(seg->tcphdr + 1);
hlipka	0:8b387bed54c2	1077	if (seg->flags & TF_SEG_OPTS_MSS) {
hlipka	0:8b387bed54c2	1078	TCP_BUILD_MSS_OPTION(*opts);
hlipka	0:8b387bed54c2	1079	opts += 1;
hlipka	0:8b387bed54c2	1080	}
hlipka	0:8b387bed54c2	1081	#if LWIP_TCP_TIMESTAMPS
hlipka	0:8b387bed54c2	1082	pcb->ts_lastacksent = pcb->rcv_nxt;
hlipka	0:8b387bed54c2	1083
hlipka	0:8b387bed54c2	1084	if (seg->flags & TF_SEG_OPTS_TS) {
hlipka	0:8b387bed54c2	1085	tcp_build_timestamp_option(pcb, opts);
hlipka	0:8b387bed54c2	1086	opts += 3;
hlipka	0:8b387bed54c2	1087	}
hlipka	0:8b387bed54c2	1088	#endif
hlipka	0:8b387bed54c2	1089
hlipka	0:8b387bed54c2	1090	/* If we don't have a local IP address, we get one by
hlipka	0:8b387bed54c2	1091	calling ip_route(). */
hlipka	0:8b387bed54c2	1092	if (ip_addr_isany(&(pcb->local_ip))) {
hlipka	0:8b387bed54c2	1093	netif = ip_route(&(pcb->remote_ip));
hlipka	0:8b387bed54c2	1094	if (netif == NULL) {
hlipka	0:8b387bed54c2	1095	return;
hlipka	0:8b387bed54c2	1096	}
hlipka	0:8b387bed54c2	1097	ip_addr_copy(pcb->local_ip, netif->ip_addr);
hlipka	0:8b387bed54c2	1098	}
hlipka	0:8b387bed54c2	1099
hlipka	0:8b387bed54c2	1100	/* Set retransmission timer running if it is not currently enabled */
hlipka	0:8b387bed54c2	1101	if(pcb->rtime == -1) {
hlipka	0:8b387bed54c2	1102	pcb->rtime = 0;
hlipka	0:8b387bed54c2	1103	}
hlipka	0:8b387bed54c2	1104
hlipka	0:8b387bed54c2	1105	if (pcb->rttest == 0) {
hlipka	0:8b387bed54c2	1106	pcb->rttest = tcp_ticks;
hlipka	0:8b387bed54c2	1107	pcb->rtseq = ntohl(seg->tcphdr->seqno);
hlipka	0:8b387bed54c2	1108
hlipka	0:8b387bed54c2	1109	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
hlipka	0:8b387bed54c2	1110	}
hlipka	0:8b387bed54c2	1111	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
hlipka	0:8b387bed54c2	1112	htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
hlipka	0:8b387bed54c2	1113	seg->len));
hlipka	0:8b387bed54c2	1114
hlipka	0:8b387bed54c2	1115	len = (u16_t)((u8_t )seg->tcphdr - (u8_t )seg->p->payload);
hlipka	0:8b387bed54c2	1116
hlipka	0:8b387bed54c2	1117	seg->p->len -= len;
hlipka	0:8b387bed54c2	1118	seg->p->tot_len -= len;
hlipka	0:8b387bed54c2	1119
hlipka	0:8b387bed54c2	1120	seg->p->payload = seg->tcphdr;
hlipka	0:8b387bed54c2	1121
hlipka	0:8b387bed54c2	1122	seg->tcphdr->chksum = 0;
hlipka	0:8b387bed54c2	1123	#if CHECKSUM_GEN_TCP
hlipka	0:8b387bed54c2	1124	#if TCP_CHECKSUM_ON_COPY
hlipka	0:8b387bed54c2	1125	{
hlipka	0:8b387bed54c2	1126	u32_t acc;
hlipka	0:8b387bed54c2	1127	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
hlipka	0:8b387bed54c2	1128	u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
hlipka	0:8b387bed54c2	1129	&(pcb->remote_ip),
hlipka	0:8b387bed54c2	1130	IP_PROTO_TCP, seg->p->tot_len);
hlipka	0:8b387bed54c2	1131	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
hlipka	0:8b387bed54c2	1132	if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
hlipka	0:8b387bed54c2	1133	LWIP_ASSERT("data included but not checksummed",
hlipka	0:8b387bed54c2	1134	seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
hlipka	0:8b387bed54c2	1135	}
hlipka	0:8b387bed54c2	1136
hlipka	0:8b387bed54c2	1137	/* rebuild TCP header checksum (TCP header changes for retransmissions!) */
hlipka	0:8b387bed54c2	1138	acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
hlipka	0:8b387bed54c2	1139	&(pcb->remote_ip),
hlipka	0:8b387bed54c2	1140	IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
hlipka	0:8b387bed54c2	1141	/* add payload checksum */
hlipka	0:8b387bed54c2	1142	if (seg->chksum_swapped) {
hlipka	0:8b387bed54c2	1143	seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
hlipka	0:8b387bed54c2	1144	seg->chksum_swapped = 0;
hlipka	0:8b387bed54c2	1145	}
hlipka	0:8b387bed54c2	1146	acc += (u16_t)~(seg->chksum);
hlipka	0:8b387bed54c2	1147	seg->tcphdr->chksum = FOLD_U32T(acc);
hlipka	0:8b387bed54c2	1148	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
hlipka	0:8b387bed54c2	1149	if (chksum_slow != seg->tcphdr->chksum) {
hlipka	0:8b387bed54c2	1150	LWIP_DEBUGF(TCP_DEBUG \| LWIP_DBG_LEVEL_WARNING,
hlipka	0:8b387bed54c2	1151	("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
hlipka	0:8b387bed54c2	1152	seg->tcphdr->chksum, chksum_slow));
hlipka	0:8b387bed54c2	1153	seg->tcphdr->chksum = chksum_slow;
hlipka	0:8b387bed54c2	1154	}
hlipka	0:8b387bed54c2	1155	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
hlipka	0:8b387bed54c2	1156	}
hlipka	0:8b387bed54c2	1157	#else /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	1158	seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
hlipka	0:8b387bed54c2	1159	&(pcb->remote_ip),
hlipka	0:8b387bed54c2	1160	IP_PROTO_TCP, seg->p->tot_len);
hlipka	0:8b387bed54c2	1161	#endif /* TCP_CHECKSUM_ON_COPY */
hlipka	0:8b387bed54c2	1162	#endif /* CHECKSUM_GEN_TCP */
hlipka	0:8b387bed54c2	1163	TCP_STATS_INC(tcp.xmit);
hlipka	0:8b387bed54c2	1164
hlipka	0:8b387bed54c2	1165	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: Before ip_out seqno = %"U32_F"\n",
hlipka	0:8b387bed54c2	1166	htonl(seg->tcphdr->seqno))); //DG
hlipka	0:8b387bed54c2	1167
hlipka	0:8b387bed54c2	1168	#if LWIP_NETIF_HWADDRHINT
hlipka	0:8b387bed54c2	1169	ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
hlipka	0:8b387bed54c2	1170	IP_PROTO_TCP, &(pcb->addr_hint));
hlipka	0:8b387bed54c2	1171	#else /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1172	ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
hlipka	0:8b387bed54c2	1173	IP_PROTO_TCP);
hlipka	0:8b387bed54c2	1174	#endif /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1175
hlipka	0:8b387bed54c2	1176	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: After ip_out seqno = %"U32_F"\n",
hlipka	0:8b387bed54c2	1177	htonl(seg->tcphdr->seqno))); //DG
hlipka	0:8b387bed54c2	1178
hlipka	0:8b387bed54c2	1179
hlipka	0:8b387bed54c2	1180	}
hlipka	0:8b387bed54c2	1181
hlipka	0:8b387bed54c2	1182	/**
hlipka	0:8b387bed54c2	1183	* Send a TCP RESET packet (empty segment with RST flag set) either to
hlipka	0:8b387bed54c2	1184	* abort a connection or to show that there is no matching local connection
hlipka	0:8b387bed54c2	1185	* for a received segment.
hlipka	0:8b387bed54c2	1186	*
hlipka	0:8b387bed54c2	1187	* Called by tcp_abort() (to abort a local connection), tcp_input() (if no
hlipka	0:8b387bed54c2	1188	* matching local pcb was found), tcp_listen_input() (if incoming segment
hlipka	0:8b387bed54c2	1189	* has ACK flag set) and tcp_process() (received segment in the wrong state)
hlipka	0:8b387bed54c2	1190	*
hlipka	0:8b387bed54c2	1191	* Since a RST segment is in most cases not sent for an active connection,
hlipka	0:8b387bed54c2	1192	* tcp_rst() has a number of arguments that are taken from a tcp_pcb for
hlipka	0:8b387bed54c2	1193	* most other segment output functions.
hlipka	0:8b387bed54c2	1194	*
hlipka	0:8b387bed54c2	1195	* @param seqno the sequence number to use for the outgoing segment
hlipka	0:8b387bed54c2	1196	* @param ackno the acknowledge number to use for the outgoing segment
hlipka	0:8b387bed54c2	1197	* @param local_ip the local IP address to send the segment from
hlipka	0:8b387bed54c2	1198	* @param remote_ip the remote IP address to send the segment to
hlipka	0:8b387bed54c2	1199	* @param local_port the local TCP port to send the segment from
hlipka	0:8b387bed54c2	1200	* @param remote_port the remote TCP port to send the segment to
hlipka	0:8b387bed54c2	1201	*/
hlipka	0:8b387bed54c2	1202	void
hlipka	0:8b387bed54c2	1203	tcp_rst(u32_t seqno, u32_t ackno,
hlipka	0:8b387bed54c2	1204	ip_addr_t local_ip, ip_addr_t remote_ip,
hlipka	0:8b387bed54c2	1205	u16_t local_port, u16_t remote_port)
hlipka	0:8b387bed54c2	1206	{
hlipka	0:8b387bed54c2	1207	struct pbuf *p;
hlipka	0:8b387bed54c2	1208	struct tcp_hdr *tcphdr;
hlipka	0:8b387bed54c2	1209	p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
hlipka	0:8b387bed54c2	1210	if (p == NULL) {
hlipka	0:8b387bed54c2	1211	LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
hlipka	0:8b387bed54c2	1212	return;
hlipka	0:8b387bed54c2	1213	}
hlipka	0:8b387bed54c2	1214	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
hlipka	0:8b387bed54c2	1215	(p->len >= sizeof(struct tcp_hdr)));
hlipka	0:8b387bed54c2	1216
hlipka	0:8b387bed54c2	1217	tcphdr = (struct tcp_hdr *)p->payload;
hlipka	0:8b387bed54c2	1218	tcphdr->src = htons(local_port);
hlipka	0:8b387bed54c2	1219	tcphdr->dest = htons(remote_port);
hlipka	0:8b387bed54c2	1220	tcphdr->seqno = htonl(seqno);
hlipka	0:8b387bed54c2	1221	tcphdr->ackno = htonl(ackno);
hlipka	0:8b387bed54c2	1222	TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST \| TCP_ACK);
hlipka	0:8b387bed54c2	1223	tcphdr->wnd = PP_HTONS(TCP_WND);
hlipka	0:8b387bed54c2	1224	tcphdr->chksum = 0;
hlipka	0:8b387bed54c2	1225	tcphdr->urgp = 0;
hlipka	0:8b387bed54c2	1226
hlipka	0:8b387bed54c2	1227	#if CHECKSUM_GEN_TCP
hlipka	0:8b387bed54c2	1228	tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
hlipka	0:8b387bed54c2	1229	IP_PROTO_TCP, p->tot_len);
hlipka	0:8b387bed54c2	1230	#endif
hlipka	0:8b387bed54c2	1231	TCP_STATS_INC(tcp.xmit);
hlipka	0:8b387bed54c2	1232	snmp_inc_tcpoutrsts();
hlipka	0:8b387bed54c2	1233	/* Send output with hardcoded TTL since we have no access to the pcb */
hlipka	0:8b387bed54c2	1234	ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
hlipka	0:8b387bed54c2	1235	pbuf_free(p);
hlipka	0:8b387bed54c2	1236	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
hlipka	0:8b387bed54c2	1237	}
hlipka	0:8b387bed54c2	1238
hlipka	0:8b387bed54c2	1239	/**
hlipka	0:8b387bed54c2	1240	* Requeue all unacked segments for retransmission
hlipka	0:8b387bed54c2	1241	*
hlipka	0:8b387bed54c2	1242	* Called by tcp_slowtmr() for slow retransmission.
hlipka	0:8b387bed54c2	1243	*
hlipka	0:8b387bed54c2	1244	* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
hlipka	0:8b387bed54c2	1245	*/
hlipka	0:8b387bed54c2	1246	void
hlipka	0:8b387bed54c2	1247	tcp_rexmit_rto(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	1248	{
hlipka	0:8b387bed54c2	1249	struct tcp_seg *seg;
hlipka	0:8b387bed54c2	1250
hlipka	0:8b387bed54c2	1251	if (pcb->unacked == NULL) {
hlipka	0:8b387bed54c2	1252	return;
hlipka	0:8b387bed54c2	1253	}
hlipka	0:8b387bed54c2	1254
hlipka	0:8b387bed54c2	1255	/* Move all unacked segments to the head of the unsent queue */
hlipka	0:8b387bed54c2	1256	for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
hlipka	0:8b387bed54c2	1257	/* concatenate unsent queue after unacked queue */
hlipka	0:8b387bed54c2	1258	seg->next = pcb->unsent;
hlipka	0:8b387bed54c2	1259	/* unsent queue is the concatenated queue (of unacked, unsent) */
hlipka	0:8b387bed54c2	1260	pcb->unsent = pcb->unacked;
hlipka	0:8b387bed54c2	1261	/* unacked queue is now empty */
hlipka	0:8b387bed54c2	1262	pcb->unacked = NULL;
hlipka	0:8b387bed54c2	1263
hlipka	0:8b387bed54c2	1264	/* increment number of retransmissions */
hlipka	0:8b387bed54c2	1265	++pcb->nrtx;
hlipka	0:8b387bed54c2	1266
hlipka	0:8b387bed54c2	1267	/* Don't take any RTT measurements after retransmitting. */
hlipka	0:8b387bed54c2	1268	pcb->rttest = 0;
hlipka	0:8b387bed54c2	1269
hlipka	0:8b387bed54c2	1270	/* Do the actual retransmission */
hlipka	0:8b387bed54c2	1271	tcp_output(pcb);
hlipka	0:8b387bed54c2	1272	}
hlipka	0:8b387bed54c2	1273
hlipka	0:8b387bed54c2	1274	/**
hlipka	0:8b387bed54c2	1275	* Requeue the first unacked segment for retransmission
hlipka	0:8b387bed54c2	1276	*
hlipka	0:8b387bed54c2	1277	* Called by tcp_receive() for fast retramsmit.
hlipka	0:8b387bed54c2	1278	*
hlipka	0:8b387bed54c2	1279	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
hlipka	0:8b387bed54c2	1280	*/
hlipka	0:8b387bed54c2	1281	void
hlipka	0:8b387bed54c2	1282	tcp_rexmit(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	1283	{
hlipka	0:8b387bed54c2	1284	struct tcp_seg *seg;
hlipka	0:8b387bed54c2	1285	struct tcp_seg **cur_seg;
hlipka	0:8b387bed54c2	1286
hlipka	0:8b387bed54c2	1287	if (pcb->unacked == NULL) {
hlipka	0:8b387bed54c2	1288	return;
hlipka	0:8b387bed54c2	1289	}
hlipka	0:8b387bed54c2	1290
hlipka	0:8b387bed54c2	1291	/* Move the first unacked segment to the unsent queue */
hlipka	0:8b387bed54c2	1292	/* Keep the unsent queue sorted. */
hlipka	0:8b387bed54c2	1293	seg = pcb->unacked;
hlipka	0:8b387bed54c2	1294	pcb->unacked = seg->next;
hlipka	0:8b387bed54c2	1295
hlipka	0:8b387bed54c2	1296	cur_seg = &(pcb->unsent);
hlipka	0:8b387bed54c2	1297	while (*cur_seg &&
hlipka	0:8b387bed54c2	1298	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
hlipka	0:8b387bed54c2	1299	cur_seg = &((*cur_seg)->next );
hlipka	0:8b387bed54c2	1300	}
hlipka	0:8b387bed54c2	1301	seg->next = *cur_seg;
hlipka	0:8b387bed54c2	1302	*cur_seg = seg;
hlipka	0:8b387bed54c2	1303
hlipka	0:8b387bed54c2	1304	++pcb->nrtx;
hlipka	0:8b387bed54c2	1305
hlipka	0:8b387bed54c2	1306	/* Don't take any rtt measurements after retransmitting. */
hlipka	0:8b387bed54c2	1307	pcb->rttest = 0;
hlipka	0:8b387bed54c2	1308
hlipka	0:8b387bed54c2	1309	/* Do the actual retransmission. */
hlipka	0:8b387bed54c2	1310	snmp_inc_tcpretranssegs();
hlipka	0:8b387bed54c2	1311	/* No need to call tcp_output: we are always called from tcp_input()
hlipka	0:8b387bed54c2	1312	and thus tcp_output directly returns. */
hlipka	0:8b387bed54c2	1313	}
hlipka	0:8b387bed54c2	1314
hlipka	0:8b387bed54c2	1315
hlipka	0:8b387bed54c2	1316	/**
hlipka	0:8b387bed54c2	1317	* Handle retransmission after three dupacks received
hlipka	0:8b387bed54c2	1318	*
hlipka	0:8b387bed54c2	1319	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
hlipka	0:8b387bed54c2	1320	*/
hlipka	0:8b387bed54c2	1321	void
hlipka	0:8b387bed54c2	1322	tcp_rexmit_fast(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	1323	{
hlipka	0:8b387bed54c2	1324	if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
hlipka	0:8b387bed54c2	1325	/* This is fast retransmit. Retransmit the first unacked segment. */
hlipka	0:8b387bed54c2	1326	LWIP_DEBUGF(TCP_FR_DEBUG,
hlipka	0:8b387bed54c2	1327	("tcp_receive: dupacks %"U16_F" (%"U32_F
hlipka	0:8b387bed54c2	1328	"), fast retransmit %"U32_F"\n",
hlipka	0:8b387bed54c2	1329	(u16_t)pcb->dupacks, pcb->lastack,
hlipka	0:8b387bed54c2	1330	ntohl(pcb->unacked->tcphdr->seqno)));
hlipka	0:8b387bed54c2	1331	tcp_rexmit(pcb);
hlipka	0:8b387bed54c2	1332
hlipka	0:8b387bed54c2	1333	/* Set ssthresh to half of the minimum of the current
hlipka	0:8b387bed54c2	1334	* cwnd and the advertised window */
hlipka	0:8b387bed54c2	1335	if (pcb->cwnd > pcb->snd_wnd) {
hlipka	0:8b387bed54c2	1336	pcb->ssthresh = pcb->snd_wnd / 2;
hlipka	0:8b387bed54c2	1337	} else {
hlipka	0:8b387bed54c2	1338	pcb->ssthresh = pcb->cwnd / 2;
hlipka	0:8b387bed54c2	1339	}
hlipka	0:8b387bed54c2	1340
hlipka	0:8b387bed54c2	1341	/* The minimum value for ssthresh should be 2 MSS */
hlipka	0:8b387bed54c2	1342	if (pcb->ssthresh < 2*pcb->mss) {
hlipka	0:8b387bed54c2	1343	LWIP_DEBUGF(TCP_FR_DEBUG,
hlipka	0:8b387bed54c2	1344	("tcp_receive: The minimum value for ssthresh %"U16_F
hlipka	0:8b387bed54c2	1345	" should be min 2 mss %"U16_F"...\n",
hlipka	0:8b387bed54c2	1346	pcb->ssthresh, 2*pcb->mss));
hlipka	0:8b387bed54c2	1347	pcb->ssthresh = 2*pcb->mss;
hlipka	0:8b387bed54c2	1348	}
hlipka	0:8b387bed54c2	1349
hlipka	0:8b387bed54c2	1350	pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
hlipka	0:8b387bed54c2	1351	pcb->flags \|= TF_INFR;
hlipka	0:8b387bed54c2	1352	}
hlipka	0:8b387bed54c2	1353	}
hlipka	0:8b387bed54c2	1354
hlipka	0:8b387bed54c2	1355
hlipka	0:8b387bed54c2	1356	/**
hlipka	0:8b387bed54c2	1357	* Send keepalive packets to keep a connection active although
hlipka	0:8b387bed54c2	1358	* no data is sent over it.
hlipka	0:8b387bed54c2	1359	*
hlipka	0:8b387bed54c2	1360	* Called by tcp_slowtmr()
hlipka	0:8b387bed54c2	1361	*
hlipka	0:8b387bed54c2	1362	* @param pcb the tcp_pcb for which to send a keepalive packet
hlipka	0:8b387bed54c2	1363	*/
hlipka	0:8b387bed54c2	1364	void
hlipka	0:8b387bed54c2	1365	tcp_keepalive(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	1366	{
hlipka	0:8b387bed54c2	1367	struct pbuf *p;
hlipka	0:8b387bed54c2	1368	struct tcp_hdr *tcphdr;
hlipka	0:8b387bed54c2	1369
hlipka	0:8b387bed54c2	1370	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
hlipka	0:8b387bed54c2	1371	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
hlipka	0:8b387bed54c2	1372	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
hlipka	0:8b387bed54c2	1373
hlipka	0:8b387bed54c2	1374	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
hlipka	0:8b387bed54c2	1375	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
hlipka	0:8b387bed54c2	1376
hlipka	0:8b387bed54c2	1377	p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
hlipka	0:8b387bed54c2	1378	if(p == NULL) {
hlipka	0:8b387bed54c2	1379	LWIP_DEBUGF(TCP_DEBUG,
hlipka	0:8b387bed54c2	1380	("tcp_keepalive: could not allocate memory for pbuf\n"));
hlipka	0:8b387bed54c2	1381	return;
hlipka	0:8b387bed54c2	1382	}
hlipka	0:8b387bed54c2	1383	tcphdr = (struct tcp_hdr *)p->payload;
hlipka	0:8b387bed54c2	1384
hlipka	0:8b387bed54c2	1385	#if CHECKSUM_GEN_TCP
hlipka	0:8b387bed54c2	1386	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
hlipka	0:8b387bed54c2	1387	IP_PROTO_TCP, p->tot_len);
hlipka	0:8b387bed54c2	1388	#endif
hlipka	0:8b387bed54c2	1389	TCP_STATS_INC(tcp.xmit);
hlipka	0:8b387bed54c2	1390
hlipka	0:8b387bed54c2	1391	/* Send output to IP */
hlipka	0:8b387bed54c2	1392	#if LWIP_NETIF_HWADDRHINT
hlipka	0:8b387bed54c2	1393	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
hlipka	0:8b387bed54c2	1394	&(pcb->addr_hint));
hlipka	0:8b387bed54c2	1395	#else /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1396	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
hlipka	0:8b387bed54c2	1397	#endif /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1398
hlipka	0:8b387bed54c2	1399	pbuf_free(p);
hlipka	0:8b387bed54c2	1400
hlipka	0:8b387bed54c2	1401	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
hlipka	0:8b387bed54c2	1402	pcb->snd_nxt - 1, pcb->rcv_nxt));
hlipka	0:8b387bed54c2	1403	}
hlipka	0:8b387bed54c2	1404
hlipka	0:8b387bed54c2	1405
hlipka	0:8b387bed54c2	1406	/**
hlipka	0:8b387bed54c2	1407	* Send persist timer zero-window probes to keep a connection active
hlipka	0:8b387bed54c2	1408	* when a window update is lost.
hlipka	0:8b387bed54c2	1409	*
hlipka	0:8b387bed54c2	1410	* Called by tcp_slowtmr()
hlipka	0:8b387bed54c2	1411	*
hlipka	0:8b387bed54c2	1412	* @param pcb the tcp_pcb for which to send a zero-window probe packet
hlipka	0:8b387bed54c2	1413	*/
hlipka	0:8b387bed54c2	1414	void
hlipka	0:8b387bed54c2	1415	tcp_zero_window_probe(struct tcp_pcb *pcb)
hlipka	0:8b387bed54c2	1416	{
hlipka	0:8b387bed54c2	1417	struct pbuf *p;
hlipka	0:8b387bed54c2	1418	struct tcp_hdr *tcphdr;
hlipka	0:8b387bed54c2	1419	struct tcp_seg *seg;
hlipka	0:8b387bed54c2	1420	u16_t len;
hlipka	0:8b387bed54c2	1421	u8_t is_fin;
hlipka	0:8b387bed54c2	1422
hlipka	0:8b387bed54c2	1423	LWIP_DEBUGF(TCP_DEBUG,
hlipka	0:8b387bed54c2	1424	("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
hlipka	0:8b387bed54c2	1425	U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
hlipka	0:8b387bed54c2	1426	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
hlipka	0:8b387bed54c2	1427	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
hlipka	0:8b387bed54c2	1428
hlipka	0:8b387bed54c2	1429	LWIP_DEBUGF(TCP_DEBUG,
hlipka	0:8b387bed54c2	1430	("tcp_zero_window_probe: tcp_ticks %"U32_F
hlipka	0:8b387bed54c2	1431	" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
hlipka	0:8b387bed54c2	1432	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
hlipka	0:8b387bed54c2	1433
hlipka	0:8b387bed54c2	1434	seg = pcb->unacked;
hlipka	0:8b387bed54c2	1435
hlipka	0:8b387bed54c2	1436	if(seg == NULL) {
hlipka	0:8b387bed54c2	1437	seg = pcb->unsent;
hlipka	0:8b387bed54c2	1438	}
hlipka	0:8b387bed54c2	1439	if(seg == NULL) {
hlipka	0:8b387bed54c2	1440	return;
hlipka	0:8b387bed54c2	1441	}
hlipka	0:8b387bed54c2	1442
hlipka	0:8b387bed54c2	1443	is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
hlipka	0:8b387bed54c2	1444	/* we want to send one seqno: either FIN or data (no options) */
hlipka	0:8b387bed54c2	1445	len = is_fin ? 0 : 1;
hlipka	0:8b387bed54c2	1446
hlipka	0:8b387bed54c2	1447	p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
hlipka	0:8b387bed54c2	1448	if(p == NULL) {
hlipka	0:8b387bed54c2	1449	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
hlipka	0:8b387bed54c2	1450	return;
hlipka	0:8b387bed54c2	1451	}
hlipka	0:8b387bed54c2	1452	tcphdr = (struct tcp_hdr *)p->payload;
hlipka	0:8b387bed54c2	1453
hlipka	0:8b387bed54c2	1454	if (is_fin) {
hlipka	0:8b387bed54c2	1455	/* FIN segment, no data */
hlipka	0:8b387bed54c2	1456	TCPH_FLAGS_SET(tcphdr, TCP_ACK \| TCP_FIN);
hlipka	0:8b387bed54c2	1457	} else {
hlipka	0:8b387bed54c2	1458	/* Data segment, copy in one byte from the head of the unacked queue */
hlipka	0:8b387bed54c2	1459	((char )p->payload + TCP_HLEN) = (char )seg->dataptr;
hlipka	0:8b387bed54c2	1460	}
hlipka	0:8b387bed54c2	1461
hlipka	0:8b387bed54c2	1462	#if CHECKSUM_GEN_TCP
hlipka	0:8b387bed54c2	1463	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
hlipka	0:8b387bed54c2	1464	IP_PROTO_TCP, p->tot_len);
hlipka	0:8b387bed54c2	1465	#endif
hlipka	0:8b387bed54c2	1466	TCP_STATS_INC(tcp.xmit);
hlipka	0:8b387bed54c2	1467
hlipka	0:8b387bed54c2	1468	/* Send output to IP */
hlipka	0:8b387bed54c2	1469	#if LWIP_NETIF_HWADDRHINT
hlipka	0:8b387bed54c2	1470	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
hlipka	0:8b387bed54c2	1471	&(pcb->addr_hint));
hlipka	0:8b387bed54c2	1472	#else /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1473	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
hlipka	0:8b387bed54c2	1474	#endif /* LWIP_NETIF_HWADDRHINT*/
hlipka	0:8b387bed54c2	1475
hlipka	0:8b387bed54c2	1476	pbuf_free(p);
hlipka	0:8b387bed54c2	1477
hlipka	0:8b387bed54c2	1478	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
hlipka	0:8b387bed54c2	1479	" ackno %"U32_F".\n",
hlipka	0:8b387bed54c2	1480	pcb->snd_nxt - 1, pcb->rcv_nxt));
hlipka	0:8b387bed54c2	1481	}
hlipka	0:8b387bed54c2	1482	#endif /* LWIP_TCP */

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Type:	Library
Created:	10 Jan 2011
Imports:	412
Forks:	1
Commits:	2
Dependents:	9
Dependencies:	2
Followers:	6

lwip/core/tcp_out.c@0:8b387bed54c2, 2011-01-10 (annotated)

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