TCPSpeedTest - I have a problem getting this to work. Server onl…

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Jesper Taxbøl / Mbed 2 deprecated TCPSpeedTest

I have a problem getting this to work. Server only recieves half of the data being sent. Whats wrong

lwip/core/tcp_out.c@0:66300c77c6e9, 2011-03-29 (annotated)

Committer:: tax
Date:: Tue Mar 29 13:20:15 2011 +0000
Revision:: 0:66300c77c6e9

Who changed what in which revision?

User	Revision	Line number	New contents of line
tax	0:66300c77c6e9	1	/**
tax	0:66300c77c6e9	2	* @file
tax	0:66300c77c6e9	3	* Transmission Control Protocol, outgoing traffic
tax	0:66300c77c6e9	4	*
tax	0:66300c77c6e9	5	* The output functions of TCP.
tax	0:66300c77c6e9	6	*
tax	0:66300c77c6e9	7	*/
tax	0:66300c77c6e9	8
tax	0:66300c77c6e9	9	/*
tax	0:66300c77c6e9	10	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
tax	0:66300c77c6e9	11	* All rights reserved.
tax	0:66300c77c6e9	12	*
tax	0:66300c77c6e9	13	* Redistribution and use in source and binary forms, with or without modification,
tax	0:66300c77c6e9	14	* are permitted provided that the following conditions are met:
tax	0:66300c77c6e9	15	*
tax	0:66300c77c6e9	16	* 1. Redistributions of source code must retain the above copyright notice,
tax	0:66300c77c6e9	17	* this list of conditions and the following disclaimer.
tax	0:66300c77c6e9	18	* 2. Redistributions in binary form must reproduce the above copyright notice,
tax	0:66300c77c6e9	19	* this list of conditions and the following disclaimer in the documentation
tax	0:66300c77c6e9	20	* and/or other materials provided with the distribution.
tax	0:66300c77c6e9	21	* 3. The name of the author may not be used to endorse or promote products
tax	0:66300c77c6e9	22	* derived from this software without specific prior written permission.
tax	0:66300c77c6e9	23	*
tax	0:66300c77c6e9	24	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
tax	0:66300c77c6e9	25	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
tax	0:66300c77c6e9	26	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
tax	0:66300c77c6e9	27	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
tax	0:66300c77c6e9	28	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
tax	0:66300c77c6e9	29	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
tax	0:66300c77c6e9	30	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
tax	0:66300c77c6e9	31	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
tax	0:66300c77c6e9	32	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
tax	0:66300c77c6e9	33	* OF SUCH DAMAGE.
tax	0:66300c77c6e9	34	*
tax	0:66300c77c6e9	35	* This file is part of the lwIP TCP/IP stack.
tax	0:66300c77c6e9	36	*
tax	0:66300c77c6e9	37	* Author: Adam Dunkels <adam@sics.se>
tax	0:66300c77c6e9	38	*
tax	0:66300c77c6e9	39	*/
tax	0:66300c77c6e9	40
tax	0:66300c77c6e9	41	#include "lwip/opt.h"
tax	0:66300c77c6e9	42
tax	0:66300c77c6e9	43	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
tax	0:66300c77c6e9	44
tax	0:66300c77c6e9	45	#include "lwip/tcp_impl.h"
tax	0:66300c77c6e9	46	#include "lwip/def.h"
tax	0:66300c77c6e9	47	#include "lwip/mem.h"
tax	0:66300c77c6e9	48	#include "lwip/memp.h"
tax	0:66300c77c6e9	49	#include "lwip/sys.h"
tax	0:66300c77c6e9	50	#include "lwip/ip_addr.h"
tax	0:66300c77c6e9	51	#include "lwip/netif.h"
tax	0:66300c77c6e9	52	#include "lwip/inet_chksum.h"
tax	0:66300c77c6e9	53	#include "lwip/stats.h"
tax	0:66300c77c6e9	54	#include "lwip/snmp.h"
tax	0:66300c77c6e9	55
tax	0:66300c77c6e9	56	#include <string.h>
tax	0:66300c77c6e9	57
tax	0:66300c77c6e9	58	/* Define some copy-macros for checksum-on-copy so that the code looks
tax	0:66300c77c6e9	59	nicer by preventing too many ifdef's. */
tax	0:66300c77c6e9	60	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	61	#define TCP_DATA_COPY(dst, src, len, seg) do { \
tax	0:66300c77c6e9	62	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
tax	0:66300c77c6e9	63	len, &seg->chksum, &seg->chksum_swapped); \
tax	0:66300c77c6e9	64	seg->flags \|= TF_SEG_DATA_CHECKSUMMED; } while(0)
tax	0:66300c77c6e9	65	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
tax	0:66300c77c6e9	66	tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
tax	0:66300c77c6e9	67	#else /* TCP_CHECKSUM_ON_COPY*/
tax	0:66300c77c6e9	68	#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
tax	0:66300c77c6e9	69	#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
tax	0:66300c77c6e9	70	#endif /* TCP_CHECKSUM_ON_COPY*/
tax	0:66300c77c6e9	71
tax	0:66300c77c6e9	72	/** Define this to 1 for an extra check that the output checksum is valid
tax	0:66300c77c6e9	73	* (usefule when the checksum is generated by the application, not the stack) */
tax	0:66300c77c6e9	74	#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
tax	0:66300c77c6e9	75	#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
tax	0:66300c77c6e9	76	#endif
tax	0:66300c77c6e9	77
tax	0:66300c77c6e9	78	/* Forward declarations.*/
tax	0:66300c77c6e9	79	static void tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb);
tax	0:66300c77c6e9	80
tax	0:66300c77c6e9	81	/** Allocate a pbuf and create a tcphdr at p->payload, used for output
tax	0:66300c77c6e9	82	* functions other than the default tcp_output -> tcp_output_segment
tax	0:66300c77c6e9	83	* (e.g. tcp_send_empty_ack, etc.)
tax	0:66300c77c6e9	84	*
tax	0:66300c77c6e9	85	* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
tax	0:66300c77c6e9	86	* @param optlen length of header-options
tax	0:66300c77c6e9	87	* @param datalen length of tcp data to reserve in pbuf
tax	0:66300c77c6e9	88	* @param seqno_be seqno in network byte order (big-endian)
tax	0:66300c77c6e9	89	* @return pbuf with p->payload being the tcp_hdr
tax	0:66300c77c6e9	90	*/
tax	0:66300c77c6e9	91	static struct pbuf *
tax	0:66300c77c6e9	92	tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
tax	0:66300c77c6e9	93	u32_t seqno_be /* already in network byte order */)
tax	0:66300c77c6e9	94	{
tax	0:66300c77c6e9	95	struct tcp_hdr *tcphdr;
tax	0:66300c77c6e9	96	struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
tax	0:66300c77c6e9	97	if (p != NULL) {
tax	0:66300c77c6e9	98	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
tax	0:66300c77c6e9	99	(p->len >= TCP_HLEN + optlen));
tax	0:66300c77c6e9	100	tcphdr = (struct tcp_hdr *)p->payload;
tax	0:66300c77c6e9	101	tcphdr->src = htons(pcb->local_port);
tax	0:66300c77c6e9	102	tcphdr->dest = htons(pcb->remote_port);
tax	0:66300c77c6e9	103	tcphdr->seqno = seqno_be;
tax	0:66300c77c6e9	104	tcphdr->ackno = htonl(pcb->rcv_nxt);
tax	0:66300c77c6e9	105	TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
tax	0:66300c77c6e9	106	tcphdr->wnd = htons(pcb->rcv_ann_wnd);
tax	0:66300c77c6e9	107	tcphdr->chksum = 0;
tax	0:66300c77c6e9	108	tcphdr->urgp = 0;
tax	0:66300c77c6e9	109
tax	0:66300c77c6e9	110	/* If we're sending a packet, update the announced right window edge */
tax	0:66300c77c6e9	111	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
tax	0:66300c77c6e9	112	}
tax	0:66300c77c6e9	113	return p;
tax	0:66300c77c6e9	114	}
tax	0:66300c77c6e9	115
tax	0:66300c77c6e9	116	/**
tax	0:66300c77c6e9	117	* Called by tcp_close() to send a segment including FIN flag but not data.
tax	0:66300c77c6e9	118	*
tax	0:66300c77c6e9	119	* @param pcb the tcp_pcb over which to send a segment
tax	0:66300c77c6e9	120	* @return ERR_OK if sent, another err_t otherwise
tax	0:66300c77c6e9	121	*/
tax	0:66300c77c6e9	122	err_t
tax	0:66300c77c6e9	123	tcp_send_fin(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	124	{
tax	0:66300c77c6e9	125	/* first, try to add the fin to the last unsent segment */
tax	0:66300c77c6e9	126	if (pcb->unsent != NULL) {
tax	0:66300c77c6e9	127	struct tcp_seg *last_unsent;
tax	0:66300c77c6e9	128	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
tax	0:66300c77c6e9	129	last_unsent = last_unsent->next);
tax	0:66300c77c6e9	130
tax	0:66300c77c6e9	131	if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN \| TCP_FIN \| TCP_RST)) == 0) {
tax	0:66300c77c6e9	132	/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
tax	0:66300c77c6e9	133	TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
tax	0:66300c77c6e9	134	return ERR_OK;
tax	0:66300c77c6e9	135	}
tax	0:66300c77c6e9	136	}
tax	0:66300c77c6e9	137	/* no data, no length, flags, copy=1, no optdata */
tax	0:66300c77c6e9	138	return tcp_enqueue_flags(pcb, TCP_FIN);
tax	0:66300c77c6e9	139	}
tax	0:66300c77c6e9	140
tax	0:66300c77c6e9	141	/**
tax	0:66300c77c6e9	142	* Create a TCP segment with prefilled header.
tax	0:66300c77c6e9	143	*
tax	0:66300c77c6e9	144	* Called by tcp_write and tcp_enqueue_flags.
tax	0:66300c77c6e9	145	*
tax	0:66300c77c6e9	146	* @param pcb Protocol control block for the TCP connection.
tax	0:66300c77c6e9	147	* @param p pbuf that is used to hold the TCP header.
tax	0:66300c77c6e9	148	* @param flags TCP flags for header.
tax	0:66300c77c6e9	149	* @param seqno TCP sequence number of this packet
tax	0:66300c77c6e9	150	* @param optflags options to include in TCP header
tax	0:66300c77c6e9	151	* @return a new tcp_seg pointing to p, or NULL.
tax	0:66300c77c6e9	152	* The TCP header is filled in except ackno and wnd.
tax	0:66300c77c6e9	153	* p is freed on failure.
tax	0:66300c77c6e9	154	*/
tax	0:66300c77c6e9	155	static struct tcp_seg *
tax	0:66300c77c6e9	156	tcp_create_segment(struct tcp_pcb pcb, struct pbuf p, u8_t flags, u32_t seqno, u8_t optflags)
tax	0:66300c77c6e9	157	{
tax	0:66300c77c6e9	158	struct tcp_seg *seg;
tax	0:66300c77c6e9	159	u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
tax	0:66300c77c6e9	160
tax	0:66300c77c6e9	161	if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
tax	0:66300c77c6e9	162	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no memory.\n"));
tax	0:66300c77c6e9	163	pbuf_free(p);
tax	0:66300c77c6e9	164	return NULL;
tax	0:66300c77c6e9	165	}
tax	0:66300c77c6e9	166	seg->flags = optflags;
tax	0:66300c77c6e9	167	seg->next = NULL;
tax	0:66300c77c6e9	168	seg->p = p;
tax	0:66300c77c6e9	169	seg->dataptr = p->payload;
tax	0:66300c77c6e9	170	seg->len = p->tot_len - optlen;
tax	0:66300c77c6e9	171	#if TCP_OVERSIZE_DBGCHECK
tax	0:66300c77c6e9	172	seg->oversize_left = 0;
tax	0:66300c77c6e9	173	#endif /* TCP_OVERSIZE_DBGCHECK */
tax	0:66300c77c6e9	174	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	175	seg->chksum = 0;
tax	0:66300c77c6e9	176	seg->chksum_swapped = 0;
tax	0:66300c77c6e9	177	/* check optflags */
tax	0:66300c77c6e9	178	LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
tax	0:66300c77c6e9	179	(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
tax	0:66300c77c6e9	180	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	181
tax	0:66300c77c6e9	182	/* build TCP header */
tax	0:66300c77c6e9	183	if (pbuf_header(p, TCP_HLEN)) {
tax	0:66300c77c6e9	184	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
tax	0:66300c77c6e9	185	TCP_STATS_INC(tcp.err);
tax	0:66300c77c6e9	186	tcp_seg_free(seg);
tax	0:66300c77c6e9	187	return NULL;
tax	0:66300c77c6e9	188	}
tax	0:66300c77c6e9	189	seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
tax	0:66300c77c6e9	190	seg->tcphdr->src = htons(pcb->local_port);
tax	0:66300c77c6e9	191	seg->tcphdr->dest = htons(pcb->remote_port);
tax	0:66300c77c6e9	192	seg->tcphdr->seqno = htonl(seqno);
tax	0:66300c77c6e9	193	/* ackno is set in tcp_output */
tax	0:66300c77c6e9	194	TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
tax	0:66300c77c6e9	195	/* wnd and chksum are set in tcp_output */
tax	0:66300c77c6e9	196	seg->tcphdr->urgp = 0;
tax	0:66300c77c6e9	197	return seg;
tax	0:66300c77c6e9	198	}
tax	0:66300c77c6e9	199
tax	0:66300c77c6e9	200	/**
tax	0:66300c77c6e9	201	* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
tax	0:66300c77c6e9	202	*
tax	0:66300c77c6e9	203	* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
tax	0:66300c77c6e9	204	* there may be extra bytes available at the end.
tax	0:66300c77c6e9	205	*
tax	0:66300c77c6e9	206	* @param layer flag to define header size.
tax	0:66300c77c6e9	207	* @param length size of the pbuf's payload.
tax	0:66300c77c6e9	208	* @param max_length maximum usable size of payload+oversize.
tax	0:66300c77c6e9	209	* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
tax	0:66300c77c6e9	210	* @param pcb The TCP connection that willo enqueue the pbuf.
tax	0:66300c77c6e9	211	* @param apiflags API flags given to tcp_write.
tax	0:66300c77c6e9	212	* @param first_seg true when this pbuf will be used in the first enqueued segment.
tax	0:66300c77c6e9	213	* @param
tax	0:66300c77c6e9	214	*/
tax	0:66300c77c6e9	215	#if TCP_OVERSIZE
tax	0:66300c77c6e9	216	static struct pbuf *
tax	0:66300c77c6e9	217	tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
tax	0:66300c77c6e9	218	u16_t oversize, struct tcp_pcb pcb, u8_t apiflags,
tax	0:66300c77c6e9	219	u8_t first_seg)
tax	0:66300c77c6e9	220	{
tax	0:66300c77c6e9	221	struct pbuf *p;
tax	0:66300c77c6e9	222	u16_t alloc = length;
tax	0:66300c77c6e9	223
tax	0:66300c77c6e9	224	#if LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	225	LWIP_UNUSED_ARG(max_length);
tax	0:66300c77c6e9	226	LWIP_UNUSED_ARG(pcb);
tax	0:66300c77c6e9	227	LWIP_UNUSED_ARG(apiflags);
tax	0:66300c77c6e9	228	LWIP_UNUSED_ARG(first_seg);
tax	0:66300c77c6e9	229	/* always create MSS-sized pbufs */
tax	0:66300c77c6e9	230	alloc = TCP_MSS;
tax	0:66300c77c6e9	231	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	232	if (length < max_length) {
tax	0:66300c77c6e9	233	/* Should we allocate an oversized pbuf, or just the minimum
tax	0:66300c77c6e9	234	* length required? If tcp_write is going to be called again
tax	0:66300c77c6e9	235	* before this segment is transmitted, we want the oversized
tax	0:66300c77c6e9	236	* buffer. If the segment will be transmitted immediately, we can
tax	0:66300c77c6e9	237	* save memory by allocating only length. We use a simple
tax	0:66300c77c6e9	238	* heuristic based on the following information:
tax	0:66300c77c6e9	239	*
tax	0:66300c77c6e9	240	* Did the user set TCP_WRITE_FLAG_MORE?
tax	0:66300c77c6e9	241	*
tax	0:66300c77c6e9	242	* Will the Nagle algorithm defer transmission of this segment?
tax	0:66300c77c6e9	243	*/
tax	0:66300c77c6e9	244	if ((apiflags & TCP_WRITE_FLAG_MORE) \|\|
tax	0:66300c77c6e9	245	(!(pcb->flags & TF_NODELAY) &&
tax	0:66300c77c6e9	246	(!first_seg \|\|
tax	0:66300c77c6e9	247	pcb->unsent != NULL \|\|
tax	0:66300c77c6e9	248	pcb->unacked != NULL))) {
tax	0:66300c77c6e9	249	alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
tax	0:66300c77c6e9	250	}
tax	0:66300c77c6e9	251	}
tax	0:66300c77c6e9	252	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	253	p = pbuf_alloc(layer, alloc, PBUF_RAM);
tax	0:66300c77c6e9	254	if (p == NULL) {
tax	0:66300c77c6e9	255	return NULL;
tax	0:66300c77c6e9	256	}
tax	0:66300c77c6e9	257	LWIP_ASSERT("need unchained pbuf", p->next == NULL);
tax	0:66300c77c6e9	258	*oversize = p->len - length;
tax	0:66300c77c6e9	259	/* trim p->len to the currently used size */
tax	0:66300c77c6e9	260	p->len = p->tot_len = length;
tax	0:66300c77c6e9	261	return p;
tax	0:66300c77c6e9	262	}
tax	0:66300c77c6e9	263	#else /* TCP_OVERSIZE */
tax	0:66300c77c6e9	264	#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
tax	0:66300c77c6e9	265	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	266
tax	0:66300c77c6e9	267	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	268	/** Add a checksum of newly added data to the segment */
tax	0:66300c77c6e9	269	static void
tax	0:66300c77c6e9	270	tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
tax	0:66300c77c6e9	271	u8_t *seg_chksum_swapped)
tax	0:66300c77c6e9	272	{
tax	0:66300c77c6e9	273	u32_t helper;
tax	0:66300c77c6e9	274	/* add chksum to old chksum and fold to u16_t */
tax	0:66300c77c6e9	275	helper = chksum + *seg_chksum;
tax	0:66300c77c6e9	276	chksum = FOLD_U32T(helper);
tax	0:66300c77c6e9	277	if ((len & 1) != 0) {
tax	0:66300c77c6e9	278	seg_chksum_swapped = 1 - seg_chksum_swapped;
tax	0:66300c77c6e9	279	chksum = SWAP_BYTES_IN_WORD(chksum);
tax	0:66300c77c6e9	280	}
tax	0:66300c77c6e9	281	*seg_chksum = chksum;
tax	0:66300c77c6e9	282	}
tax	0:66300c77c6e9	283	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	284
tax	0:66300c77c6e9	285	/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
tax	0:66300c77c6e9	286	*
tax	0:66300c77c6e9	287	* @param pcb the tcp pcb to check for
tax	0:66300c77c6e9	288	* @param len length of data to send (checked agains snd_buf)
tax	0:66300c77c6e9	289	* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
tax	0:66300c77c6e9	290	*/
tax	0:66300c77c6e9	291	static err_t
tax	0:66300c77c6e9	292	tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
tax	0:66300c77c6e9	293	{
tax	0:66300c77c6e9	294	/* connection is in invalid state for data transmission? */
tax	0:66300c77c6e9	295	if ((pcb->state != ESTABLISHED) &&
tax	0:66300c77c6e9	296	(pcb->state != CLOSE_WAIT) &&
tax	0:66300c77c6e9	297	(pcb->state != SYN_SENT) &&
tax	0:66300c77c6e9	298	(pcb->state != SYN_RCVD)) {
tax	0:66300c77c6e9	299	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_STATE \| LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
tax	0:66300c77c6e9	300	return ERR_CONN;
tax	0:66300c77c6e9	301	} else if (len == 0) {
tax	0:66300c77c6e9	302	return ERR_OK;
tax	0:66300c77c6e9	303	}
tax	0:66300c77c6e9	304
tax	0:66300c77c6e9	305	/* fail on too much data */
tax	0:66300c77c6e9	306	if (len > pcb->snd_buf) {
tax	0:66300c77c6e9	307	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
tax	0:66300c77c6e9	308	len, pcb->snd_buf));
tax	0:66300c77c6e9	309	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	310	return ERR_MEM;
tax	0:66300c77c6e9	311	}
tax	0:66300c77c6e9	312
tax	0:66300c77c6e9	313	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
tax	0:66300c77c6e9	314
tax	0:66300c77c6e9	315	/* If total number of pbufs on the unsent/unacked queues exceeds the
tax	0:66300c77c6e9	316	* configured maximum, return an error */
tax	0:66300c77c6e9	317	/* check for configured max queuelen and possible overflow */
tax	0:66300c77c6e9	318	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
tax	0:66300c77c6e9	319	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
tax	0:66300c77c6e9	320	pcb->snd_queuelen, TCP_SND_QUEUELEN));
tax	0:66300c77c6e9	321	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	322	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	323	return ERR_MEM;
tax	0:66300c77c6e9	324	}
tax	0:66300c77c6e9	325	if (pcb->snd_queuelen != 0) {
tax	0:66300c77c6e9	326	LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
tax	0:66300c77c6e9	327	pcb->unacked != NULL \|\| pcb->unsent != NULL);
tax	0:66300c77c6e9	328	} else {
tax	0:66300c77c6e9	329	LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
tax	0:66300c77c6e9	330	pcb->unacked == NULL && pcb->unsent == NULL);
tax	0:66300c77c6e9	331	}
tax	0:66300c77c6e9	332	return ERR_OK;
tax	0:66300c77c6e9	333	}
tax	0:66300c77c6e9	334
tax	0:66300c77c6e9	335	/**
tax	0:66300c77c6e9	336	* Write data for sending (but does not send it immediately).
tax	0:66300c77c6e9	337	*
tax	0:66300c77c6e9	338	* It waits in the expectation of more data being sent soon (as
tax	0:66300c77c6e9	339	* it can send them more efficiently by combining them together).
tax	0:66300c77c6e9	340	* To prompt the system to send data now, call tcp_output() after
tax	0:66300c77c6e9	341	* calling tcp_write().
tax	0:66300c77c6e9	342	*
tax	0:66300c77c6e9	343	* @param pcb Protocol control block for the TCP connection to enqueue data for.
tax	0:66300c77c6e9	344	* @param arg Pointer to the data to be enqueued for sending.
tax	0:66300c77c6e9	345	* @param len Data length in bytes
tax	0:66300c77c6e9	346	* @param apiflags combination of following flags :
tax	0:66300c77c6e9	347	* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
tax	0:66300c77c6e9	348	* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
tax	0:66300c77c6e9	349	* @return ERR_OK if enqueued, another err_t on error
tax	0:66300c77c6e9	350	*/
tax	0:66300c77c6e9	351	err_t
tax	0:66300c77c6e9	352	tcp_write(struct tcp_pcb pcb, const void arg, u16_t len, u8_t apiflags)
tax	0:66300c77c6e9	353	{
tax	0:66300c77c6e9	354	struct pbuf *concat_p = NULL;
tax	0:66300c77c6e9	355	struct tcp_seg last_unsent = NULL, seg = NULL, prev_seg = NULL, queue = NULL;
tax	0:66300c77c6e9	356	u16_t pos = 0; /* position in 'arg' data */
tax	0:66300c77c6e9	357	u16_t queuelen;
tax	0:66300c77c6e9	358	u8_t optlen = 0;
tax	0:66300c77c6e9	359	u8_t optflags = 0;
tax	0:66300c77c6e9	360	#if TCP_OVERSIZE
tax	0:66300c77c6e9	361	u16_t oversize = 0;
tax	0:66300c77c6e9	362	u16_t oversize_used = 0;
tax	0:66300c77c6e9	363	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	364	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	365	u16_t concat_chksum = 0;
tax	0:66300c77c6e9	366	u8_t concat_chksum_swapped = 0;
tax	0:66300c77c6e9	367	u16_t concat_chksummed = 0;
tax	0:66300c77c6e9	368	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	369	err_t err;
tax	0:66300c77c6e9	370
tax	0:66300c77c6e9	371	#if LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	372	/* Always copy to try to create single pbufs for TX */
tax	0:66300c77c6e9	373	apiflags \|= TCP_WRITE_FLAG_COPY;
tax	0:66300c77c6e9	374	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	375
tax	0:66300c77c6e9	376	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
tax	0:66300c77c6e9	377	(void *)pcb, arg, len, (u16_t)apiflags));
tax	0:66300c77c6e9	378	LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
tax	0:66300c77c6e9	379	arg != NULL, return ERR_ARG;);
tax	0:66300c77c6e9	380
tax	0:66300c77c6e9	381	err = tcp_write_checks(pcb, len);
tax	0:66300c77c6e9	382	if (err != ERR_OK) {
tax	0:66300c77c6e9	383	return err;
tax	0:66300c77c6e9	384	}
tax	0:66300c77c6e9	385	queuelen = pcb->snd_queuelen;
tax	0:66300c77c6e9	386
tax	0:66300c77c6e9	387	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	388	if ((pcb->flags & TF_TIMESTAMP)) {
tax	0:66300c77c6e9	389	optflags = TF_SEG_OPTS_TS;
tax	0:66300c77c6e9	390	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
tax	0:66300c77c6e9	391	}
tax	0:66300c77c6e9	392	#endif /* LWIP_TCP_TIMESTAMPS */
tax	0:66300c77c6e9	393
tax	0:66300c77c6e9	394
tax	0:66300c77c6e9	395	/*
tax	0:66300c77c6e9	396	* TCP segmentation is done in three phases with increasing complexity:
tax	0:66300c77c6e9	397	*
tax	0:66300c77c6e9	398	* 1. Copy data directly into an oversized pbuf.
tax	0:66300c77c6e9	399	* 2. Chain a new pbuf to the end of pcb->unsent.
tax	0:66300c77c6e9	400	* 3. Create new segments.
tax	0:66300c77c6e9	401	*
tax	0:66300c77c6e9	402	* We may run out of memory at any point. In that case we must
tax	0:66300c77c6e9	403	* return ERR_MEM and not change anything in pcb. Therefore, all
tax	0:66300c77c6e9	404	* changes are recorded in local variables and committed at the end
tax	0:66300c77c6e9	405	* of the function. Some pcb fields are maintained in local copies:
tax	0:66300c77c6e9	406	*
tax	0:66300c77c6e9	407	* queuelen = pcb->snd_queuelen
tax	0:66300c77c6e9	408	* oversize = pcb->unsent_oversize
tax	0:66300c77c6e9	409	*
tax	0:66300c77c6e9	410	* These variables are set consistently by the phases:
tax	0:66300c77c6e9	411	*
tax	0:66300c77c6e9	412	* seg points to the last segment tampered with.
tax	0:66300c77c6e9	413	*
tax	0:66300c77c6e9	414	* pos records progress as data is segmented.
tax	0:66300c77c6e9	415	*/
tax	0:66300c77c6e9	416
tax	0:66300c77c6e9	417	/* Find the tail of the unsent queue. */
tax	0:66300c77c6e9	418	if (pcb->unsent != NULL) {
tax	0:66300c77c6e9	419	u16_t space;
tax	0:66300c77c6e9	420	u16_t unsent_optlen;
tax	0:66300c77c6e9	421
tax	0:66300c77c6e9	422	/* @todo: this could be sped up by keeping last_unsent in the pcb */
tax	0:66300c77c6e9	423	for (last_unsent = pcb->unsent; last_unsent->next != NULL;
tax	0:66300c77c6e9	424	last_unsent = last_unsent->next);
tax	0:66300c77c6e9	425
tax	0:66300c77c6e9	426	/* Usable space at the end of the last unsent segment */
tax	0:66300c77c6e9	427	unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
tax	0:66300c77c6e9	428	space = pcb->mss - (last_unsent->len + unsent_optlen);
tax	0:66300c77c6e9	429
tax	0:66300c77c6e9	430	/*
tax	0:66300c77c6e9	431	* Phase 1: Copy data directly into an oversized pbuf.
tax	0:66300c77c6e9	432	*
tax	0:66300c77c6e9	433	* The number of bytes copied is recorded in the oversize_used
tax	0:66300c77c6e9	434	* variable. The actual copying is done at the bottom of the
tax	0:66300c77c6e9	435	* function.
tax	0:66300c77c6e9	436	*/
tax	0:66300c77c6e9	437	#if TCP_OVERSIZE
tax	0:66300c77c6e9	438	#if TCP_OVERSIZE_DBGCHECK
tax	0:66300c77c6e9	439	/* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
tax	0:66300c77c6e9	440	LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
tax	0:66300c77c6e9	441	pcb->unsent_oversize == last_unsent->oversize_left);
tax	0:66300c77c6e9	442	#endif /* TCP_OVERSIZE_DBGCHECK */
tax	0:66300c77c6e9	443	oversize = pcb->unsent_oversize;
tax	0:66300c77c6e9	444	if (oversize > 0) {
tax	0:66300c77c6e9	445	LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
tax	0:66300c77c6e9	446	seg = last_unsent;
tax	0:66300c77c6e9	447	oversize_used = oversize < len ? oversize : len;
tax	0:66300c77c6e9	448	pos += oversize_used;
tax	0:66300c77c6e9	449	oversize -= oversize_used;
tax	0:66300c77c6e9	450	space -= oversize_used;
tax	0:66300c77c6e9	451	}
tax	0:66300c77c6e9	452	/* now we are either finished or oversize is zero */
tax	0:66300c77c6e9	453	LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) \|\| (pos == len));
tax	0:66300c77c6e9	454	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	455
tax	0:66300c77c6e9	456	/*
tax	0:66300c77c6e9	457	* Phase 2: Chain a new pbuf to the end of pcb->unsent.
tax	0:66300c77c6e9	458	*
tax	0:66300c77c6e9	459	* We don't extend segments containing SYN/FIN flags or options
tax	0:66300c77c6e9	460	* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
tax	0:66300c77c6e9	461	* the end.
tax	0:66300c77c6e9	462	*/
tax	0:66300c77c6e9	463	if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
tax	0:66300c77c6e9	464	u16_t seglen = space < len - pos ? space : len - pos;
tax	0:66300c77c6e9	465	seg = last_unsent;
tax	0:66300c77c6e9	466
tax	0:66300c77c6e9	467	/* Create a pbuf with a copy or reference to seglen bytes. We
tax	0:66300c77c6e9	468	* can use PBUF_RAW here since the data appears in the middle of
tax	0:66300c77c6e9	469	* a segment. A header will never be prepended. */
tax	0:66300c77c6e9	470	if (apiflags & TCP_WRITE_FLAG_COPY) {
tax	0:66300c77c6e9	471	/* Data is copied */
tax	0:66300c77c6e9	472	if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
tax	0:66300c77c6e9	473	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
tax	0:66300c77c6e9	474	("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
tax	0:66300c77c6e9	475	seglen));
tax	0:66300c77c6e9	476	goto memerr;
tax	0:66300c77c6e9	477	}
tax	0:66300c77c6e9	478	#if TCP_OVERSIZE_DBGCHECK
tax	0:66300c77c6e9	479	last_unsent->oversize_left = oversize;
tax	0:66300c77c6e9	480	#endif /* TCP_OVERSIZE_DBGCHECK */
tax	0:66300c77c6e9	481	TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
tax	0:66300c77c6e9	482	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	483	concat_chksummed += seglen;
tax	0:66300c77c6e9	484	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	485	} else {
tax	0:66300c77c6e9	486	/* Data is not copied */
tax	0:66300c77c6e9	487	if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
tax	0:66300c77c6e9	488	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2,
tax	0:66300c77c6e9	489	("tcp_write: could not allocate memory for zero-copy pbuf\n"));
tax	0:66300c77c6e9	490	goto memerr;
tax	0:66300c77c6e9	491	}
tax	0:66300c77c6e9	492	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	493	/* calculate the checksum of nocopy-data */
tax	0:66300c77c6e9	494	tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
tax	0:66300c77c6e9	495	&concat_chksum, &concat_chksum_swapped);
tax	0:66300c77c6e9	496	concat_chksummed += seglen;
tax	0:66300c77c6e9	497	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	498	/* reference the non-volatile payload data */
tax	0:66300c77c6e9	499	concat_p->payload = (u8_t*)arg + pos;
tax	0:66300c77c6e9	500	}
tax	0:66300c77c6e9	501
tax	0:66300c77c6e9	502	pos += seglen;
tax	0:66300c77c6e9	503	queuelen += pbuf_clen(concat_p);
tax	0:66300c77c6e9	504	}
tax	0:66300c77c6e9	505	} else {
tax	0:66300c77c6e9	506	#if TCP_OVERSIZE
tax	0:66300c77c6e9	507	LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
tax	0:66300c77c6e9	508	pcb->unsent_oversize == 0);
tax	0:66300c77c6e9	509	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	510	}
tax	0:66300c77c6e9	511
tax	0:66300c77c6e9	512	/*
tax	0:66300c77c6e9	513	* Phase 3: Create new segments.
tax	0:66300c77c6e9	514	*
tax	0:66300c77c6e9	515	* The new segments are chained together in the local 'queue'
tax	0:66300c77c6e9	516	* variable, ready to be appended to pcb->unsent.
tax	0:66300c77c6e9	517	*/
tax	0:66300c77c6e9	518	while (pos < len) {
tax	0:66300c77c6e9	519	struct pbuf *p;
tax	0:66300c77c6e9	520	u16_t left = len - pos;
tax	0:66300c77c6e9	521	u16_t max_len = pcb->mss - optlen;
tax	0:66300c77c6e9	522	u16_t seglen = left > max_len ? max_len : left;
tax	0:66300c77c6e9	523	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	524	u16_t chksum = 0;
tax	0:66300c77c6e9	525	u8_t chksum_swapped = 0;
tax	0:66300c77c6e9	526	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	527
tax	0:66300c77c6e9	528	if (apiflags & TCP_WRITE_FLAG_COPY) {
tax	0:66300c77c6e9	529	/* If copy is set, memory should be allocated and data copied
tax	0:66300c77c6e9	530	* into pbuf */
tax	0:66300c77c6e9	531	if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
tax	0:66300c77c6e9	532	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
tax	0:66300c77c6e9	533	goto memerr;
tax	0:66300c77c6e9	534	}
tax	0:66300c77c6e9	535	LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
tax	0:66300c77c6e9	536	(p->len >= seglen));
tax	0:66300c77c6e9	537	TCP_DATA_COPY2((char )p->payload + optlen, (u8_t)arg + pos, seglen, &chksum, &chksum_swapped);
tax	0:66300c77c6e9	538	} else {
tax	0:66300c77c6e9	539	/* Copy is not set: First allocate a pbuf for holding the data.
tax	0:66300c77c6e9	540	* Since the referenced data is available at least until it is
tax	0:66300c77c6e9	541	* sent out on the link (as it has to be ACKed by the remote
tax	0:66300c77c6e9	542	* party) we can safely use PBUF_ROM instead of PBUF_REF here.
tax	0:66300c77c6e9	543	*/
tax	0:66300c77c6e9	544	struct pbuf *p2;
tax	0:66300c77c6e9	545	#if TCP_OVERSIZE
tax	0:66300c77c6e9	546	LWIP_ASSERT("oversize == 0", oversize == 0);
tax	0:66300c77c6e9	547	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	548	if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
tax	0:66300c77c6e9	549	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
tax	0:66300c77c6e9	550	goto memerr;
tax	0:66300c77c6e9	551	}
tax	0:66300c77c6e9	552	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	553	/* calculate the checksum of nocopy-data */
tax	0:66300c77c6e9	554	chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
tax	0:66300c77c6e9	555	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	556	/* reference the non-volatile payload data */
tax	0:66300c77c6e9	557	p2->payload = (u8_t*)arg + pos;
tax	0:66300c77c6e9	558
tax	0:66300c77c6e9	559	/* Second, allocate a pbuf for the headers. */
tax	0:66300c77c6e9	560	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
tax	0:66300c77c6e9	561	/* If allocation fails, we have to deallocate the data pbuf as
tax	0:66300c77c6e9	562	* well. */
tax	0:66300c77c6e9	563	pbuf_free(p2);
tax	0:66300c77c6e9	564	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: could not allocate memory for header pbuf\n"));
tax	0:66300c77c6e9	565	goto memerr;
tax	0:66300c77c6e9	566	}
tax	0:66300c77c6e9	567	/* Concatenate the headers and data pbufs together. */
tax	0:66300c77c6e9	568	pbuf_cat(p/header/, p2/data/);
tax	0:66300c77c6e9	569	}
tax	0:66300c77c6e9	570
tax	0:66300c77c6e9	571	queuelen += pbuf_clen(p);
tax	0:66300c77c6e9	572
tax	0:66300c77c6e9	573	/* Now that there are more segments queued, we check again if the
tax	0:66300c77c6e9	574	* length of the queue exceeds the configured maximum or
tax	0:66300c77c6e9	575	* overflows. */
tax	0:66300c77c6e9	576	if ((queuelen > TCP_SND_QUEUELEN) \|\| (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
tax	0:66300c77c6e9	577	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
tax	0:66300c77c6e9	578	pbuf_free(p);
tax	0:66300c77c6e9	579	goto memerr;
tax	0:66300c77c6e9	580	}
tax	0:66300c77c6e9	581
tax	0:66300c77c6e9	582	if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
tax	0:66300c77c6e9	583	goto memerr;
tax	0:66300c77c6e9	584	}
tax	0:66300c77c6e9	585	#if TCP_OVERSIZE_DBGCHECK
tax	0:66300c77c6e9	586	seg->oversize_left = oversize;
tax	0:66300c77c6e9	587	#endif /* TCP_OVERSIZE_DBGCHECK */
tax	0:66300c77c6e9	588	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	589	seg->chksum = chksum;
tax	0:66300c77c6e9	590	seg->chksum_swapped = chksum_swapped;
tax	0:66300c77c6e9	591	seg->flags \|= TF_SEG_DATA_CHECKSUMMED;
tax	0:66300c77c6e9	592	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	593	/* Fix dataptr for the nocopy case */
tax	0:66300c77c6e9	594	if ((apiflags & TCP_WRITE_FLAG_COPY) == 0) {
tax	0:66300c77c6e9	595	seg->dataptr = (u8_t*)arg + pos;
tax	0:66300c77c6e9	596	}
tax	0:66300c77c6e9	597
tax	0:66300c77c6e9	598	/* first segment of to-be-queued data? */
tax	0:66300c77c6e9	599	if (queue == NULL) {
tax	0:66300c77c6e9	600	queue = seg;
tax	0:66300c77c6e9	601	} else {
tax	0:66300c77c6e9	602	/* Attach the segment to the end of the queued segments */
tax	0:66300c77c6e9	603	LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
tax	0:66300c77c6e9	604	prev_seg->next = seg;
tax	0:66300c77c6e9	605	}
tax	0:66300c77c6e9	606	/* remember last segment of to-be-queued data for next iteration */
tax	0:66300c77c6e9	607	prev_seg = seg;
tax	0:66300c77c6e9	608
tax	0:66300c77c6e9	609	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
tax	0:66300c77c6e9	610	ntohl(seg->tcphdr->seqno),
tax	0:66300c77c6e9	611	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
tax	0:66300c77c6e9	612
tax	0:66300c77c6e9	613	pos += seglen;
tax	0:66300c77c6e9	614	}
tax	0:66300c77c6e9	615
tax	0:66300c77c6e9	616	/*
tax	0:66300c77c6e9	617	* All three segmentation phases were successful. We can commit the
tax	0:66300c77c6e9	618	* transaction.
tax	0:66300c77c6e9	619	*/
tax	0:66300c77c6e9	620
tax	0:66300c77c6e9	621	/*
tax	0:66300c77c6e9	622	* Phase 1: If data has been added to the preallocated tail of
tax	0:66300c77c6e9	623	* last_unsent, we update the length fields of the pbuf chain.
tax	0:66300c77c6e9	624	*/
tax	0:66300c77c6e9	625	#if TCP_OVERSIZE
tax	0:66300c77c6e9	626	if (oversize_used > 0) {
tax	0:66300c77c6e9	627	struct pbuf *p;
tax	0:66300c77c6e9	628	/* Bump tot_len of whole chain, len of tail */
tax	0:66300c77c6e9	629	for (p = last_unsent->p; p; p = p->next) {
tax	0:66300c77c6e9	630	p->tot_len += oversize_used;
tax	0:66300c77c6e9	631	if (p->next == NULL) {
tax	0:66300c77c6e9	632	TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
tax	0:66300c77c6e9	633	p->len += oversize_used;
tax	0:66300c77c6e9	634	}
tax	0:66300c77c6e9	635	}
tax	0:66300c77c6e9	636	last_unsent->len += oversize_used;
tax	0:66300c77c6e9	637	#if TCP_OVERSIZE_DBGCHECK
tax	0:66300c77c6e9	638	last_unsent->oversize_left -= oversize_used;
tax	0:66300c77c6e9	639	#endif /* TCP_OVERSIZE_DBGCHECK */
tax	0:66300c77c6e9	640	}
tax	0:66300c77c6e9	641	pcb->unsent_oversize = oversize;
tax	0:66300c77c6e9	642	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	643
tax	0:66300c77c6e9	644	/*
tax	0:66300c77c6e9	645	* Phase 2: concat_p can be concatenated onto last_unsent->p
tax	0:66300c77c6e9	646	*/
tax	0:66300c77c6e9	647	if (concat_p != NULL) {
tax	0:66300c77c6e9	648	LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
tax	0:66300c77c6e9	649	(last_unsent != NULL));
tax	0:66300c77c6e9	650	pbuf_cat(last_unsent->p, concat_p);
tax	0:66300c77c6e9	651	last_unsent->len += concat_p->tot_len;
tax	0:66300c77c6e9	652	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	653	if (concat_chksummed) {
tax	0:66300c77c6e9	654	tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
tax	0:66300c77c6e9	655	&last_unsent->chksum_swapped);
tax	0:66300c77c6e9	656	last_unsent->flags \|= TF_SEG_DATA_CHECKSUMMED;
tax	0:66300c77c6e9	657	}
tax	0:66300c77c6e9	658	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	659	}
tax	0:66300c77c6e9	660
tax	0:66300c77c6e9	661	/*
tax	0:66300c77c6e9	662	* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
tax	0:66300c77c6e9	663	* is harmless
tax	0:66300c77c6e9	664	*/
tax	0:66300c77c6e9	665	if (last_unsent == NULL) {
tax	0:66300c77c6e9	666	pcb->unsent = queue;
tax	0:66300c77c6e9	667	} else {
tax	0:66300c77c6e9	668	last_unsent->next = queue;
tax	0:66300c77c6e9	669	}
tax	0:66300c77c6e9	670
tax	0:66300c77c6e9	671	/*
tax	0:66300c77c6e9	672	* Finally update the pcb state.
tax	0:66300c77c6e9	673	*/
tax	0:66300c77c6e9	674	pcb->snd_lbb += len;
tax	0:66300c77c6e9	675	pcb->snd_buf -= len;
tax	0:66300c77c6e9	676	pcb->snd_queuelen = queuelen;
tax	0:66300c77c6e9	677
tax	0:66300c77c6e9	678	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
tax	0:66300c77c6e9	679	pcb->snd_queuelen));
tax	0:66300c77c6e9	680	if (pcb->snd_queuelen != 0) {
tax	0:66300c77c6e9	681	LWIP_ASSERT("tcp_write: valid queue length",
tax	0:66300c77c6e9	682	pcb->unacked != NULL \|\| pcb->unsent != NULL);
tax	0:66300c77c6e9	683	}
tax	0:66300c77c6e9	684
tax	0:66300c77c6e9	685	/* Set the PSH flag in the last segment that we enqueued. */
tax	0:66300c77c6e9	686	if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
tax	0:66300c77c6e9	687	TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
tax	0:66300c77c6e9	688	}
tax	0:66300c77c6e9	689
tax	0:66300c77c6e9	690	return ERR_OK;
tax	0:66300c77c6e9	691	memerr:
tax	0:66300c77c6e9	692	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	693	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	694
tax	0:66300c77c6e9	695	if (concat_p != NULL) {
tax	0:66300c77c6e9	696	pbuf_free(concat_p);
tax	0:66300c77c6e9	697	}
tax	0:66300c77c6e9	698	if (queue != NULL) {
tax	0:66300c77c6e9	699	tcp_segs_free(queue);
tax	0:66300c77c6e9	700	}
tax	0:66300c77c6e9	701	if (pcb->snd_queuelen != 0) {
tax	0:66300c77c6e9	702	LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL \|\|
tax	0:66300c77c6e9	703	pcb->unsent != NULL);
tax	0:66300c77c6e9	704	}
tax	0:66300c77c6e9	705	LWIP_DEBUGF(TCP_QLEN_DEBUG \| LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
tax	0:66300c77c6e9	706	return ERR_MEM;
tax	0:66300c77c6e9	707	}
tax	0:66300c77c6e9	708
tax	0:66300c77c6e9	709	/**
tax	0:66300c77c6e9	710	* Enqueue TCP options for transmission.
tax	0:66300c77c6e9	711	*
tax	0:66300c77c6e9	712	* Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
tax	0:66300c77c6e9	713	*
tax	0:66300c77c6e9	714	* @param pcb Protocol control block for the TCP connection.
tax	0:66300c77c6e9	715	* @param flags TCP header flags to set in the outgoing segment.
tax	0:66300c77c6e9	716	* @param optdata pointer to TCP options, or NULL.
tax	0:66300c77c6e9	717	* @param optlen length of TCP options in bytes.
tax	0:66300c77c6e9	718	*/
tax	0:66300c77c6e9	719	err_t
tax	0:66300c77c6e9	720	tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
tax	0:66300c77c6e9	721	{
tax	0:66300c77c6e9	722	struct pbuf *p;
tax	0:66300c77c6e9	723	struct tcp_seg *seg;
tax	0:66300c77c6e9	724	u8_t optflags = 0;
tax	0:66300c77c6e9	725	u8_t optlen = 0;
tax	0:66300c77c6e9	726
tax	0:66300c77c6e9	727	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
tax	0:66300c77c6e9	728
tax	0:66300c77c6e9	729	LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
tax	0:66300c77c6e9	730	(flags & (TCP_SYN \| TCP_FIN)) != 0);
tax	0:66300c77c6e9	731
tax	0:66300c77c6e9	732	/* check for configured max queuelen and possible overflow */
tax	0:66300c77c6e9	733	if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) \|\| (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
tax	0:66300c77c6e9	734	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
tax	0:66300c77c6e9	735	pcb->snd_queuelen, TCP_SND_QUEUELEN));
tax	0:66300c77c6e9	736	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	737	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	738	return ERR_MEM;
tax	0:66300c77c6e9	739	}
tax	0:66300c77c6e9	740
tax	0:66300c77c6e9	741	if (flags & TCP_SYN) {
tax	0:66300c77c6e9	742	optflags = TF_SEG_OPTS_MSS;
tax	0:66300c77c6e9	743	}
tax	0:66300c77c6e9	744	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	745	if ((pcb->flags & TF_TIMESTAMP)) {
tax	0:66300c77c6e9	746	optflags \|= TF_SEG_OPTS_TS;
tax	0:66300c77c6e9	747	}
tax	0:66300c77c6e9	748	#endif /* LWIP_TCP_TIMESTAMPS */
tax	0:66300c77c6e9	749	optlen = LWIP_TCP_OPT_LENGTH(optflags);
tax	0:66300c77c6e9	750
tax	0:66300c77c6e9	751	/* tcp_enqueue_flags is always called with either SYN or FIN in flags.
tax	0:66300c77c6e9	752	* We need one available snd_buf byte to do that.
tax	0:66300c77c6e9	753	* This means we can't send FIN while snd_buf==0. A better fix would be to
tax	0:66300c77c6e9	754	* not include SYN and FIN sequence numbers in the snd_buf count. */
tax	0:66300c77c6e9	755	if (pcb->snd_buf == 0) {
tax	0:66300c77c6e9	756	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| 3, ("tcp_enqueue_flags: no send buffer available\n"));
tax	0:66300c77c6e9	757	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	758	return ERR_MEM;
tax	0:66300c77c6e9	759	}
tax	0:66300c77c6e9	760
tax	0:66300c77c6e9	761	/* Allocate pbuf with room for TCP header + options */
tax	0:66300c77c6e9	762	if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
tax	0:66300c77c6e9	763	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	764	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	765	return ERR_MEM;
tax	0:66300c77c6e9	766	}
tax	0:66300c77c6e9	767	LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
tax	0:66300c77c6e9	768	(p->len >= optlen));
tax	0:66300c77c6e9	769
tax	0:66300c77c6e9	770	/* Allocate memory for tcp_seg, and fill in fields. */
tax	0:66300c77c6e9	771	if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
tax	0:66300c77c6e9	772	pcb->flags \|= TF_NAGLEMEMERR;
tax	0:66300c77c6e9	773	TCP_STATS_INC(tcp.memerr);
tax	0:66300c77c6e9	774	return ERR_MEM;
tax	0:66300c77c6e9	775	}
tax	0:66300c77c6e9	776	LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
tax	0:66300c77c6e9	777
tax	0:66300c77c6e9	778	LWIP_DEBUGF(TCP_OUTPUT_DEBUG \| LWIP_DBG_TRACE,
tax	0:66300c77c6e9	779	("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
tax	0:66300c77c6e9	780	ntohl(seg->tcphdr->seqno),
tax	0:66300c77c6e9	781	ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
tax	0:66300c77c6e9	782	(u16_t)flags));
tax	0:66300c77c6e9	783
tax	0:66300c77c6e9	784	/* Now append seg to pcb->unsent queue */
tax	0:66300c77c6e9	785	if (pcb->unsent == NULL) {
tax	0:66300c77c6e9	786	pcb->unsent = seg;
tax	0:66300c77c6e9	787	} else {
tax	0:66300c77c6e9	788	struct tcp_seg *useg;
tax	0:66300c77c6e9	789	for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
tax	0:66300c77c6e9	790	useg->next = seg;
tax	0:66300c77c6e9	791	}
tax	0:66300c77c6e9	792	#if TCP_OVERSIZE
tax	0:66300c77c6e9	793	/* The new unsent tail has no space */
tax	0:66300c77c6e9	794	pcb->unsent_oversize = 0;
tax	0:66300c77c6e9	795	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	796
tax	0:66300c77c6e9	797	/* SYN and FIN bump the sequence number */
tax	0:66300c77c6e9	798	if ((flags & TCP_SYN) \|\| (flags & TCP_FIN)) {
tax	0:66300c77c6e9	799	pcb->snd_lbb++;
tax	0:66300c77c6e9	800	/* optlen does not influence snd_buf */
tax	0:66300c77c6e9	801	pcb->snd_buf--;
tax	0:66300c77c6e9	802	}
tax	0:66300c77c6e9	803	if (flags & TCP_FIN) {
tax	0:66300c77c6e9	804	pcb->flags \|= TF_FIN;
tax	0:66300c77c6e9	805	}
tax	0:66300c77c6e9	806
tax	0:66300c77c6e9	807	/* update number of segments on the queues */
tax	0:66300c77c6e9	808	pcb->snd_queuelen += pbuf_clen(seg->p);
tax	0:66300c77c6e9	809	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
tax	0:66300c77c6e9	810	if (pcb->snd_queuelen != 0) {
tax	0:66300c77c6e9	811	LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
tax	0:66300c77c6e9	812	pcb->unacked != NULL \|\| pcb->unsent != NULL);
tax	0:66300c77c6e9	813	}
tax	0:66300c77c6e9	814
tax	0:66300c77c6e9	815	return ERR_OK;
tax	0:66300c77c6e9	816	}
tax	0:66300c77c6e9	817
tax	0:66300c77c6e9	818
tax	0:66300c77c6e9	819	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	820	/* Build a timestamp option (12 bytes long) at the specified options pointer)
tax	0:66300c77c6e9	821	*
tax	0:66300c77c6e9	822	* @param pcb tcp_pcb
tax	0:66300c77c6e9	823	* @param opts option pointer where to store the timestamp option
tax	0:66300c77c6e9	824	*/
tax	0:66300c77c6e9	825	static void
tax	0:66300c77c6e9	826	tcp_build_timestamp_option(struct tcp_pcb pcb, u32_t opts)
tax	0:66300c77c6e9	827	{
tax	0:66300c77c6e9	828	/* Pad with two NOP options to make everything nicely aligned */
tax	0:66300c77c6e9	829	opts[0] = PP_HTONL(0x0101080A);
tax	0:66300c77c6e9	830	opts[1] = htonl(sys_now());
tax	0:66300c77c6e9	831	opts[2] = htonl(pcb->ts_recent);
tax	0:66300c77c6e9	832	}
tax	0:66300c77c6e9	833	#endif
tax	0:66300c77c6e9	834
tax	0:66300c77c6e9	835	/** Send an ACK without data.
tax	0:66300c77c6e9	836	*
tax	0:66300c77c6e9	837	* @param pcb Protocol control block for the TCP connection to send the ACK
tax	0:66300c77c6e9	838	*/
tax	0:66300c77c6e9	839	err_t
tax	0:66300c77c6e9	840	tcp_send_empty_ack(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	841	{
tax	0:66300c77c6e9	842	struct pbuf *p;
tax	0:66300c77c6e9	843	struct tcp_hdr *tcphdr;
tax	0:66300c77c6e9	844	u8_t optlen = 0;
tax	0:66300c77c6e9	845
tax	0:66300c77c6e9	846	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	847	if (pcb->flags & TF_TIMESTAMP) {
tax	0:66300c77c6e9	848	optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
tax	0:66300c77c6e9	849	}
tax	0:66300c77c6e9	850	#endif
tax	0:66300c77c6e9	851
tax	0:66300c77c6e9	852	p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
tax	0:66300c77c6e9	853	if (p == NULL) {
tax	0:66300c77c6e9	854	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
tax	0:66300c77c6e9	855	return ERR_BUF;
tax	0:66300c77c6e9	856	}
tax	0:66300c77c6e9	857	tcphdr = (struct tcp_hdr *)p->payload;
tax	0:66300c77c6e9	858	LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
tax	0:66300c77c6e9	859	("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
tax	0:66300c77c6e9	860	/* remove ACK flags from the PCB, as we send an empty ACK now */
tax	0:66300c77c6e9	861	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
tax	0:66300c77c6e9	862
tax	0:66300c77c6e9	863	/* NB. MSS option is only sent on SYNs, so ignore it here */
tax	0:66300c77c6e9	864	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	865	pcb->ts_lastacksent = pcb->rcv_nxt;
tax	0:66300c77c6e9	866
tax	0:66300c77c6e9	867	if (pcb->flags & TF_TIMESTAMP) {
tax	0:66300c77c6e9	868	tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
tax	0:66300c77c6e9	869	}
tax	0:66300c77c6e9	870	#endif
tax	0:66300c77c6e9	871
tax	0:66300c77c6e9	872	#if CHECKSUM_GEN_TCP
tax	0:66300c77c6e9	873	tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
tax	0:66300c77c6e9	874	IP_PROTO_TCP, p->tot_len);
tax	0:66300c77c6e9	875	#endif
tax	0:66300c77c6e9	876	#if LWIP_NETIF_HWADDRHINT
tax	0:66300c77c6e9	877	ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
tax	0:66300c77c6e9	878	IP_PROTO_TCP, &(pcb->addr_hint));
tax	0:66300c77c6e9	879	#else /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	880	ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
tax	0:66300c77c6e9	881	IP_PROTO_TCP);
tax	0:66300c77c6e9	882	#endif /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	883	pbuf_free(p);
tax	0:66300c77c6e9	884
tax	0:66300c77c6e9	885	return ERR_OK;
tax	0:66300c77c6e9	886	}
tax	0:66300c77c6e9	887
tax	0:66300c77c6e9	888	/**
tax	0:66300c77c6e9	889	* Find out what we can send and send it
tax	0:66300c77c6e9	890	*
tax	0:66300c77c6e9	891	* @param pcb Protocol control block for the TCP connection to send data
tax	0:66300c77c6e9	892	* @return ERR_OK if data has been sent or nothing to send
tax	0:66300c77c6e9	893	* another err_t on error
tax	0:66300c77c6e9	894	*/
tax	0:66300c77c6e9	895	err_t
tax	0:66300c77c6e9	896	tcp_output(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	897	{
tax	0:66300c77c6e9	898	struct tcp_seg seg, useg;
tax	0:66300c77c6e9	899	u32_t wnd, snd_nxt;
tax	0:66300c77c6e9	900	#if TCP_CWND_DEBUG
tax	0:66300c77c6e9	901	s16_t i = 0;
tax	0:66300c77c6e9	902	#endif /* TCP_CWND_DEBUG */
tax	0:66300c77c6e9	903
tax	0:66300c77c6e9	904	/* First, check if we are invoked by the TCP input processing
tax	0:66300c77c6e9	905	code. If so, we do not output anything. Instead, we rely on the
tax	0:66300c77c6e9	906	input processing code to call us when input processing is done
tax	0:66300c77c6e9	907	with. */
tax	0:66300c77c6e9	908	if (tcp_input_pcb == pcb) {
tax	0:66300c77c6e9	909	return ERR_OK;
tax	0:66300c77c6e9	910	}
tax	0:66300c77c6e9	911
tax	0:66300c77c6e9	912	wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
tax	0:66300c77c6e9	913
tax	0:66300c77c6e9	914	seg = pcb->unsent;
tax	0:66300c77c6e9	915
tax	0:66300c77c6e9	916	/* If the TF_ACK_NOW flag is set and no data will be sent (either
tax	0:66300c77c6e9	917	* because the ->unsent queue is empty or because the window does
tax	0:66300c77c6e9	918	* not allow it), construct an empty ACK segment and send it.
tax	0:66300c77c6e9	919	*
tax	0:66300c77c6e9	920	* If data is to be sent, we will just piggyback the ACK (see below).
tax	0:66300c77c6e9	921	*/
tax	0:66300c77c6e9	922	if (pcb->flags & TF_ACK_NOW &&
tax	0:66300c77c6e9	923	(seg == NULL \|\|
tax	0:66300c77c6e9	924	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
tax	0:66300c77c6e9	925	return tcp_send_empty_ack(pcb);
tax	0:66300c77c6e9	926	}
tax	0:66300c77c6e9	927
tax	0:66300c77c6e9	928	/* useg should point to last segment on unacked queue */
tax	0:66300c77c6e9	929	useg = pcb->unacked;
tax	0:66300c77c6e9	930	if (useg != NULL) {
tax	0:66300c77c6e9	931	for (; useg->next != NULL; useg = useg->next);
tax	0:66300c77c6e9	932	}
tax	0:66300c77c6e9	933
tax	0:66300c77c6e9	934	#if TCP_OUTPUT_DEBUG
tax	0:66300c77c6e9	935	if (seg == NULL) {
tax	0:66300c77c6e9	936	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
tax	0:66300c77c6e9	937	(void*)pcb->unsent));
tax	0:66300c77c6e9	938	}
tax	0:66300c77c6e9	939	#endif /* TCP_OUTPUT_DEBUG */
tax	0:66300c77c6e9	940	#if TCP_CWND_DEBUG
tax	0:66300c77c6e9	941	if (seg == NULL) {
tax	0:66300c77c6e9	942	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
tax	0:66300c77c6e9	943	", cwnd %"U16_F", wnd %"U32_F
tax	0:66300c77c6e9	944	", seg == NULL, ack %"U32_F"\n",
tax	0:66300c77c6e9	945	pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
tax	0:66300c77c6e9	946	} else {
tax	0:66300c77c6e9	947	LWIP_DEBUGF(TCP_CWND_DEBUG,
tax	0:66300c77c6e9	948	("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
tax	0:66300c77c6e9	949	", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
tax	0:66300c77c6e9	950	pcb->snd_wnd, pcb->cwnd, wnd,
tax	0:66300c77c6e9	951	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
tax	0:66300c77c6e9	952	ntohl(seg->tcphdr->seqno), pcb->lastack));
tax	0:66300c77c6e9	953	}
tax	0:66300c77c6e9	954	#endif /* TCP_CWND_DEBUG */
tax	0:66300c77c6e9	955	/* data available and window allows it to be sent? */
tax	0:66300c77c6e9	956	while (seg != NULL &&
tax	0:66300c77c6e9	957	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
tax	0:66300c77c6e9	958	LWIP_ASSERT("RST not expected here!",
tax	0:66300c77c6e9	959	(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
tax	0:66300c77c6e9	960	/* Stop sending if the nagle algorithm would prevent it
tax	0:66300c77c6e9	961	* Don't stop:
tax	0:66300c77c6e9	962	* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
tax	0:66300c77c6e9	963	* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
tax	0:66300c77c6e9	964	* either seg->next != NULL or pcb->unacked == NULL;
tax	0:66300c77c6e9	965	* RST is no sent using tcp_write/tcp_output.
tax	0:66300c77c6e9	966	*/
tax	0:66300c77c6e9	967	if((tcp_do_output_nagle(pcb) == 0) &&
tax	0:66300c77c6e9	968	((pcb->flags & (TF_NAGLEMEMERR \| TF_FIN)) == 0)){
tax	0:66300c77c6e9	969	break;
tax	0:66300c77c6e9	970	}
tax	0:66300c77c6e9	971	#if TCP_CWND_DEBUG
tax	0:66300c77c6e9	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",
tax	0:66300c77c6e9	973	pcb->snd_wnd, pcb->cwnd, wnd,
tax	0:66300c77c6e9	974	ntohl(seg->tcphdr->seqno) + seg->len -
tax	0:66300c77c6e9	975	pcb->lastack,
tax	0:66300c77c6e9	976	ntohl(seg->tcphdr->seqno), pcb->lastack, i));
tax	0:66300c77c6e9	977	++i;
tax	0:66300c77c6e9	978	#endif /* TCP_CWND_DEBUG */
tax	0:66300c77c6e9	979
tax	0:66300c77c6e9	980	pcb->unsent = seg->next;
tax	0:66300c77c6e9	981
tax	0:66300c77c6e9	982	if (pcb->state != SYN_SENT) {
tax	0:66300c77c6e9	983	TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
tax	0:66300c77c6e9	984	pcb->flags &= ~(TF_ACK_DELAY \| TF_ACK_NOW);
tax	0:66300c77c6e9	985	}
tax	0:66300c77c6e9	986
tax	0:66300c77c6e9	987	tcp_output_segment(seg, pcb);
tax	0:66300c77c6e9	988
tax	0:66300c77c6e9	989	snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
tax	0:66300c77c6e9	990
tax	0:66300c77c6e9	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
tax	0:66300c77c6e9	992	pcb->snd_nxt, ntohl(seg->tcphdr->seqno), TCP_TCPLEN(seg), snd_nxt));
tax	0:66300c77c6e9	993
tax	0:66300c77c6e9	994	if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
tax	0:66300c77c6e9	995	pcb->snd_nxt = snd_nxt;
tax	0:66300c77c6e9	996	}
tax	0:66300c77c6e9	997	/* put segment on unacknowledged list if length > 0 */
tax	0:66300c77c6e9	998	if (TCP_TCPLEN(seg) > 0) {
tax	0:66300c77c6e9	999	seg->next = NULL;
tax	0:66300c77c6e9	1000	/* unacked list is empty? */
tax	0:66300c77c6e9	1001	if (pcb->unacked == NULL) {
tax	0:66300c77c6e9	1002	pcb->unacked = seg;
tax	0:66300c77c6e9	1003	useg = seg;
tax	0:66300c77c6e9	1004	/* unacked list is not empty? */
tax	0:66300c77c6e9	1005	} else {
tax	0:66300c77c6e9	1006	/* In the case of fast retransmit, the packet should not go to the tail
tax	0:66300c77c6e9	1007	* of the unacked queue, but rather somewhere before it. We need to check for
tax	0:66300c77c6e9	1008	* this case. -STJ Jul 27, 2004 */
tax	0:66300c77c6e9	1009	if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
tax	0:66300c77c6e9	1010	/* add segment to before tail of unacked list, keeping the list sorted */
tax	0:66300c77c6e9	1011	struct tcp_seg **cur_seg = &(pcb->unacked);
tax	0:66300c77c6e9	1012	while (*cur_seg &&
tax	0:66300c77c6e9	1013	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
tax	0:66300c77c6e9	1014	cur_seg = &((*cur_seg)->next );
tax	0:66300c77c6e9	1015	}
tax	0:66300c77c6e9	1016	seg->next = (*cur_seg);
tax	0:66300c77c6e9	1017	(*cur_seg) = seg;
tax	0:66300c77c6e9	1018	} else {
tax	0:66300c77c6e9	1019	/* add segment to tail of unacked list */
tax	0:66300c77c6e9	1020	useg->next = seg;
tax	0:66300c77c6e9	1021	useg = useg->next;
tax	0:66300c77c6e9	1022	}
tax	0:66300c77c6e9	1023	}
tax	0:66300c77c6e9	1024	/* do not queue empty segments on the unacked list */
tax	0:66300c77c6e9	1025	} else {
tax	0:66300c77c6e9	1026	tcp_seg_free(seg);
tax	0:66300c77c6e9	1027	}
tax	0:66300c77c6e9	1028	seg = pcb->unsent;
tax	0:66300c77c6e9	1029	}
tax	0:66300c77c6e9	1030	#if TCP_OVERSIZE
tax	0:66300c77c6e9	1031	if (pcb->unsent == NULL) {
tax	0:66300c77c6e9	1032	/* last unsent has been removed, reset unsent_oversize */
tax	0:66300c77c6e9	1033	pcb->unsent_oversize = 0;
tax	0:66300c77c6e9	1034	}
tax	0:66300c77c6e9	1035	#endif /* TCP_OVERSIZE */
tax	0:66300c77c6e9	1036
tax	0:66300c77c6e9	1037	if (seg != NULL && pcb->persist_backoff == 0 &&
tax	0:66300c77c6e9	1038	ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
tax	0:66300c77c6e9	1039	/* prepare for persist timer */
tax	0:66300c77c6e9	1040	pcb->persist_cnt = 0;
tax	0:66300c77c6e9	1041	pcb->persist_backoff = 1;
tax	0:66300c77c6e9	1042	}
tax	0:66300c77c6e9	1043
tax	0:66300c77c6e9	1044	pcb->flags &= ~TF_NAGLEMEMERR;
tax	0:66300c77c6e9	1045	return ERR_OK;
tax	0:66300c77c6e9	1046	}
tax	0:66300c77c6e9	1047
tax	0:66300c77c6e9	1048	/**
tax	0:66300c77c6e9	1049	* Called by tcp_output() to actually send a TCP segment over IP.
tax	0:66300c77c6e9	1050	*
tax	0:66300c77c6e9	1051	* @param seg the tcp_seg to send
tax	0:66300c77c6e9	1052	* @param pcb the tcp_pcb for the TCP connection used to send the segment
tax	0:66300c77c6e9	1053	*/
tax	0:66300c77c6e9	1054	static void
tax	0:66300c77c6e9	1055	tcp_output_segment(struct tcp_seg seg, struct tcp_pcb pcb)
tax	0:66300c77c6e9	1056	{
tax	0:66300c77c6e9	1057	u16_t len;
tax	0:66300c77c6e9	1058	struct netif *netif;
tax	0:66300c77c6e9	1059	u32_t *opts;
tax	0:66300c77c6e9	1060
tax	0:66300c77c6e9	1061	/** @bug Exclude retransmitted segments from this count. */
tax	0:66300c77c6e9	1062	snmp_inc_tcpoutsegs();
tax	0:66300c77c6e9	1063
tax	0:66300c77c6e9	1064	/* The TCP header has already been constructed, but the ackno and
tax	0:66300c77c6e9	1065	wnd fields remain. */
tax	0:66300c77c6e9	1066	seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
tax	0:66300c77c6e9	1067
tax	0:66300c77c6e9	1068	/* advertise our receive window size in this TCP segment */
tax	0:66300c77c6e9	1069	seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
tax	0:66300c77c6e9	1070
tax	0:66300c77c6e9	1071	pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
tax	0:66300c77c6e9	1072
tax	0:66300c77c6e9	1073	/* Add any requested options. NB MSS option is only set on SYN
tax	0:66300c77c6e9	1074	packets, so ignore it here */
tax	0:66300c77c6e9	1075	LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)(seg->tcphdr + 1) % 4) == 0);
tax	0:66300c77c6e9	1076	opts = (u32_t )(void )(seg->tcphdr + 1);
tax	0:66300c77c6e9	1077	if (seg->flags & TF_SEG_OPTS_MSS) {
tax	0:66300c77c6e9	1078	TCP_BUILD_MSS_OPTION(*opts);
tax	0:66300c77c6e9	1079	opts += 1;
tax	0:66300c77c6e9	1080	}
tax	0:66300c77c6e9	1081	#if LWIP_TCP_TIMESTAMPS
tax	0:66300c77c6e9	1082	pcb->ts_lastacksent = pcb->rcv_nxt;
tax	0:66300c77c6e9	1083
tax	0:66300c77c6e9	1084	if (seg->flags & TF_SEG_OPTS_TS) {
tax	0:66300c77c6e9	1085	tcp_build_timestamp_option(pcb, opts);
tax	0:66300c77c6e9	1086	opts += 3;
tax	0:66300c77c6e9	1087	}
tax	0:66300c77c6e9	1088	#endif
tax	0:66300c77c6e9	1089
tax	0:66300c77c6e9	1090	/* If we don't have a local IP address, we get one by
tax	0:66300c77c6e9	1091	calling ip_route(). */
tax	0:66300c77c6e9	1092	if (ip_addr_isany(&(pcb->local_ip))) {
tax	0:66300c77c6e9	1093	netif = ip_route(&(pcb->remote_ip));
tax	0:66300c77c6e9	1094	if (netif == NULL) {
tax	0:66300c77c6e9	1095	return;
tax	0:66300c77c6e9	1096	}
tax	0:66300c77c6e9	1097	ip_addr_copy(pcb->local_ip, netif->ip_addr);
tax	0:66300c77c6e9	1098	}
tax	0:66300c77c6e9	1099
tax	0:66300c77c6e9	1100	/* Set retransmission timer running if it is not currently enabled */
tax	0:66300c77c6e9	1101	if(pcb->rtime == -1) {
tax	0:66300c77c6e9	1102	pcb->rtime = 0;
tax	0:66300c77c6e9	1103	}
tax	0:66300c77c6e9	1104
tax	0:66300c77c6e9	1105	if (pcb->rttest == 0) {
tax	0:66300c77c6e9	1106	pcb->rttest = tcp_ticks;
tax	0:66300c77c6e9	1107	pcb->rtseq = ntohl(seg->tcphdr->seqno);
tax	0:66300c77c6e9	1108
tax	0:66300c77c6e9	1109	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
tax	0:66300c77c6e9	1110	}
tax	0:66300c77c6e9	1111	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
tax	0:66300c77c6e9	1112	htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
tax	0:66300c77c6e9	1113	seg->len));
tax	0:66300c77c6e9	1114
tax	0:66300c77c6e9	1115	len = (u16_t)((u8_t )seg->tcphdr - (u8_t )seg->p->payload);
tax	0:66300c77c6e9	1116
tax	0:66300c77c6e9	1117	seg->p->len -= len;
tax	0:66300c77c6e9	1118	seg->p->tot_len -= len;
tax	0:66300c77c6e9	1119
tax	0:66300c77c6e9	1120	seg->p->payload = seg->tcphdr;
tax	0:66300c77c6e9	1121
tax	0:66300c77c6e9	1122	seg->tcphdr->chksum = 0;
tax	0:66300c77c6e9	1123	#if CHECKSUM_GEN_TCP
tax	0:66300c77c6e9	1124	#if TCP_CHECKSUM_ON_COPY
tax	0:66300c77c6e9	1125	{
tax	0:66300c77c6e9	1126	u32_t acc;
tax	0:66300c77c6e9	1127	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
tax	0:66300c77c6e9	1128	u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
tax	0:66300c77c6e9	1129	&(pcb->remote_ip),
tax	0:66300c77c6e9	1130	IP_PROTO_TCP, seg->p->tot_len);
tax	0:66300c77c6e9	1131	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
tax	0:66300c77c6e9	1132	if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
tax	0:66300c77c6e9	1133	LWIP_ASSERT("data included but not checksummed",
tax	0:66300c77c6e9	1134	seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
tax	0:66300c77c6e9	1135	}
tax	0:66300c77c6e9	1136
tax	0:66300c77c6e9	1137	/* rebuild TCP header checksum (TCP header changes for retransmissions!) */
tax	0:66300c77c6e9	1138	acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
tax	0:66300c77c6e9	1139	&(pcb->remote_ip),
tax	0:66300c77c6e9	1140	IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
tax	0:66300c77c6e9	1141	/* add payload checksum */
tax	0:66300c77c6e9	1142	if (seg->chksum_swapped) {
tax	0:66300c77c6e9	1143	seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
tax	0:66300c77c6e9	1144	seg->chksum_swapped = 0;
tax	0:66300c77c6e9	1145	}
tax	0:66300c77c6e9	1146	acc += (u16_t)~(seg->chksum);
tax	0:66300c77c6e9	1147	seg->tcphdr->chksum = FOLD_U32T(acc);
tax	0:66300c77c6e9	1148	#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
tax	0:66300c77c6e9	1149	if (chksum_slow != seg->tcphdr->chksum) {
tax	0:66300c77c6e9	1150	LWIP_DEBUGF(TCP_DEBUG \| LWIP_DBG_LEVEL_WARNING,
tax	0:66300c77c6e9	1151	("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
tax	0:66300c77c6e9	1152	seg->tcphdr->chksum, chksum_slow));
tax	0:66300c77c6e9	1153	seg->tcphdr->chksum = chksum_slow;
tax	0:66300c77c6e9	1154	}
tax	0:66300c77c6e9	1155	#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
tax	0:66300c77c6e9	1156	}
tax	0:66300c77c6e9	1157	#else /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	1158	seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
tax	0:66300c77c6e9	1159	&(pcb->remote_ip),
tax	0:66300c77c6e9	1160	IP_PROTO_TCP, seg->p->tot_len);
tax	0:66300c77c6e9	1161	#endif /* TCP_CHECKSUM_ON_COPY */
tax	0:66300c77c6e9	1162	#endif /* CHECKSUM_GEN_TCP */
tax	0:66300c77c6e9	1163	TCP_STATS_INC(tcp.xmit);
tax	0:66300c77c6e9	1164
tax	0:66300c77c6e9	1165	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: Before ip_out seqno = %"U32_F"\n",
tax	0:66300c77c6e9	1166	htonl(seg->tcphdr->seqno))); //DG
tax	0:66300c77c6e9	1167
tax	0:66300c77c6e9	1168	#if LWIP_NETIF_HWADDRHINT
tax	0:66300c77c6e9	1169	ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
tax	0:66300c77c6e9	1170	IP_PROTO_TCP, &(pcb->addr_hint));
tax	0:66300c77c6e9	1171	#else /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1172	ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
tax	0:66300c77c6e9	1173	IP_PROTO_TCP);
tax	0:66300c77c6e9	1174	#endif /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1175
tax	0:66300c77c6e9	1176	LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: After ip_out seqno = %"U32_F"\n",
tax	0:66300c77c6e9	1177	htonl(seg->tcphdr->seqno))); //DG
tax	0:66300c77c6e9	1178
tax	0:66300c77c6e9	1179
tax	0:66300c77c6e9	1180	}
tax	0:66300c77c6e9	1181
tax	0:66300c77c6e9	1182	/**
tax	0:66300c77c6e9	1183	* Send a TCP RESET packet (empty segment with RST flag set) either to
tax	0:66300c77c6e9	1184	* abort a connection or to show that there is no matching local connection
tax	0:66300c77c6e9	1185	* for a received segment.
tax	0:66300c77c6e9	1186	*
tax	0:66300c77c6e9	1187	* Called by tcp_abort() (to abort a local connection), tcp_input() (if no
tax	0:66300c77c6e9	1188	* matching local pcb was found), tcp_listen_input() (if incoming segment
tax	0:66300c77c6e9	1189	* has ACK flag set) and tcp_process() (received segment in the wrong state)
tax	0:66300c77c6e9	1190	*
tax	0:66300c77c6e9	1191	* Since a RST segment is in most cases not sent for an active connection,
tax	0:66300c77c6e9	1192	* tcp_rst() has a number of arguments that are taken from a tcp_pcb for
tax	0:66300c77c6e9	1193	* most other segment output functions.
tax	0:66300c77c6e9	1194	*
tax	0:66300c77c6e9	1195	* @param seqno the sequence number to use for the outgoing segment
tax	0:66300c77c6e9	1196	* @param ackno the acknowledge number to use for the outgoing segment
tax	0:66300c77c6e9	1197	* @param local_ip the local IP address to send the segment from
tax	0:66300c77c6e9	1198	* @param remote_ip the remote IP address to send the segment to
tax	0:66300c77c6e9	1199	* @param local_port the local TCP port to send the segment from
tax	0:66300c77c6e9	1200	* @param remote_port the remote TCP port to send the segment to
tax	0:66300c77c6e9	1201	*/
tax	0:66300c77c6e9	1202	void
tax	0:66300c77c6e9	1203	tcp_rst(u32_t seqno, u32_t ackno,
tax	0:66300c77c6e9	1204	ip_addr_t local_ip, ip_addr_t remote_ip,
tax	0:66300c77c6e9	1205	u16_t local_port, u16_t remote_port)
tax	0:66300c77c6e9	1206	{
tax	0:66300c77c6e9	1207	struct pbuf *p;
tax	0:66300c77c6e9	1208	struct tcp_hdr *tcphdr;
tax	0:66300c77c6e9	1209	p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
tax	0:66300c77c6e9	1210	if (p == NULL) {
tax	0:66300c77c6e9	1211	LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
tax	0:66300c77c6e9	1212	return;
tax	0:66300c77c6e9	1213	}
tax	0:66300c77c6e9	1214	LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
tax	0:66300c77c6e9	1215	(p->len >= sizeof(struct tcp_hdr)));
tax	0:66300c77c6e9	1216
tax	0:66300c77c6e9	1217	tcphdr = (struct tcp_hdr *)p->payload;
tax	0:66300c77c6e9	1218	tcphdr->src = htons(local_port);
tax	0:66300c77c6e9	1219	tcphdr->dest = htons(remote_port);
tax	0:66300c77c6e9	1220	tcphdr->seqno = htonl(seqno);
tax	0:66300c77c6e9	1221	tcphdr->ackno = htonl(ackno);
tax	0:66300c77c6e9	1222	TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST \| TCP_ACK);
tax	0:66300c77c6e9	1223	tcphdr->wnd = PP_HTONS(TCP_WND);
tax	0:66300c77c6e9	1224	tcphdr->chksum = 0;
tax	0:66300c77c6e9	1225	tcphdr->urgp = 0;
tax	0:66300c77c6e9	1226
tax	0:66300c77c6e9	1227	#if CHECKSUM_GEN_TCP
tax	0:66300c77c6e9	1228	tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
tax	0:66300c77c6e9	1229	IP_PROTO_TCP, p->tot_len);
tax	0:66300c77c6e9	1230	#endif
tax	0:66300c77c6e9	1231	TCP_STATS_INC(tcp.xmit);
tax	0:66300c77c6e9	1232	snmp_inc_tcpoutrsts();
tax	0:66300c77c6e9	1233	/* Send output with hardcoded TTL since we have no access to the pcb */
tax	0:66300c77c6e9	1234	ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
tax	0:66300c77c6e9	1235	pbuf_free(p);
tax	0:66300c77c6e9	1236	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
tax	0:66300c77c6e9	1237	}
tax	0:66300c77c6e9	1238
tax	0:66300c77c6e9	1239	/**
tax	0:66300c77c6e9	1240	* Requeue all unacked segments for retransmission
tax	0:66300c77c6e9	1241	*
tax	0:66300c77c6e9	1242	* Called by tcp_slowtmr() for slow retransmission.
tax	0:66300c77c6e9	1243	*
tax	0:66300c77c6e9	1244	* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
tax	0:66300c77c6e9	1245	*/
tax	0:66300c77c6e9	1246	void
tax	0:66300c77c6e9	1247	tcp_rexmit_rto(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	1248	{
tax	0:66300c77c6e9	1249	struct tcp_seg *seg;
tax	0:66300c77c6e9	1250
tax	0:66300c77c6e9	1251	if (pcb->unacked == NULL) {
tax	0:66300c77c6e9	1252	return;
tax	0:66300c77c6e9	1253	}
tax	0:66300c77c6e9	1254
tax	0:66300c77c6e9	1255	/* Move all unacked segments to the head of the unsent queue */
tax	0:66300c77c6e9	1256	for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
tax	0:66300c77c6e9	1257	/* concatenate unsent queue after unacked queue */
tax	0:66300c77c6e9	1258	seg->next = pcb->unsent;
tax	0:66300c77c6e9	1259	/* unsent queue is the concatenated queue (of unacked, unsent) */
tax	0:66300c77c6e9	1260	pcb->unsent = pcb->unacked;
tax	0:66300c77c6e9	1261	/* unacked queue is now empty */
tax	0:66300c77c6e9	1262	pcb->unacked = NULL;
tax	0:66300c77c6e9	1263
tax	0:66300c77c6e9	1264	/* increment number of retransmissions */
tax	0:66300c77c6e9	1265	++pcb->nrtx;
tax	0:66300c77c6e9	1266
tax	0:66300c77c6e9	1267	/* Don't take any RTT measurements after retransmitting. */
tax	0:66300c77c6e9	1268	pcb->rttest = 0;
tax	0:66300c77c6e9	1269
tax	0:66300c77c6e9	1270	/* Do the actual retransmission */
tax	0:66300c77c6e9	1271	tcp_output(pcb);
tax	0:66300c77c6e9	1272	}
tax	0:66300c77c6e9	1273
tax	0:66300c77c6e9	1274	/**
tax	0:66300c77c6e9	1275	* Requeue the first unacked segment for retransmission
tax	0:66300c77c6e9	1276	*
tax	0:66300c77c6e9	1277	* Called by tcp_receive() for fast retramsmit.
tax	0:66300c77c6e9	1278	*
tax	0:66300c77c6e9	1279	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
tax	0:66300c77c6e9	1280	*/
tax	0:66300c77c6e9	1281	void
tax	0:66300c77c6e9	1282	tcp_rexmit(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	1283	{
tax	0:66300c77c6e9	1284	struct tcp_seg *seg;
tax	0:66300c77c6e9	1285	struct tcp_seg **cur_seg;
tax	0:66300c77c6e9	1286
tax	0:66300c77c6e9	1287	if (pcb->unacked == NULL) {
tax	0:66300c77c6e9	1288	return;
tax	0:66300c77c6e9	1289	}
tax	0:66300c77c6e9	1290
tax	0:66300c77c6e9	1291	/* Move the first unacked segment to the unsent queue */
tax	0:66300c77c6e9	1292	/* Keep the unsent queue sorted. */
tax	0:66300c77c6e9	1293	seg = pcb->unacked;
tax	0:66300c77c6e9	1294	pcb->unacked = seg->next;
tax	0:66300c77c6e9	1295
tax	0:66300c77c6e9	1296	cur_seg = &(pcb->unsent);
tax	0:66300c77c6e9	1297	while (*cur_seg &&
tax	0:66300c77c6e9	1298	TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
tax	0:66300c77c6e9	1299	cur_seg = &((*cur_seg)->next );
tax	0:66300c77c6e9	1300	}
tax	0:66300c77c6e9	1301	seg->next = *cur_seg;
tax	0:66300c77c6e9	1302	*cur_seg = seg;
tax	0:66300c77c6e9	1303
tax	0:66300c77c6e9	1304	++pcb->nrtx;
tax	0:66300c77c6e9	1305
tax	0:66300c77c6e9	1306	/* Don't take any rtt measurements after retransmitting. */
tax	0:66300c77c6e9	1307	pcb->rttest = 0;
tax	0:66300c77c6e9	1308
tax	0:66300c77c6e9	1309	/* Do the actual retransmission. */
tax	0:66300c77c6e9	1310	snmp_inc_tcpretranssegs();
tax	0:66300c77c6e9	1311	/* No need to call tcp_output: we are always called from tcp_input()
tax	0:66300c77c6e9	1312	and thus tcp_output directly returns. */
tax	0:66300c77c6e9	1313	}
tax	0:66300c77c6e9	1314
tax	0:66300c77c6e9	1315
tax	0:66300c77c6e9	1316	/**
tax	0:66300c77c6e9	1317	* Handle retransmission after three dupacks received
tax	0:66300c77c6e9	1318	*
tax	0:66300c77c6e9	1319	* @param pcb the tcp_pcb for which to retransmit the first unacked segment
tax	0:66300c77c6e9	1320	*/
tax	0:66300c77c6e9	1321	void
tax	0:66300c77c6e9	1322	tcp_rexmit_fast(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	1323	{
tax	0:66300c77c6e9	1324	if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
tax	0:66300c77c6e9	1325	/* This is fast retransmit. Retransmit the first unacked segment. */
tax	0:66300c77c6e9	1326	LWIP_DEBUGF(TCP_FR_DEBUG,
tax	0:66300c77c6e9	1327	("tcp_receive: dupacks %"U16_F" (%"U32_F
tax	0:66300c77c6e9	1328	"), fast retransmit %"U32_F"\n",
tax	0:66300c77c6e9	1329	(u16_t)pcb->dupacks, pcb->lastack,
tax	0:66300c77c6e9	1330	ntohl(pcb->unacked->tcphdr->seqno)));
tax	0:66300c77c6e9	1331	tcp_rexmit(pcb);
tax	0:66300c77c6e9	1332
tax	0:66300c77c6e9	1333	/* Set ssthresh to half of the minimum of the current
tax	0:66300c77c6e9	1334	* cwnd and the advertised window */
tax	0:66300c77c6e9	1335	if (pcb->cwnd > pcb->snd_wnd) {
tax	0:66300c77c6e9	1336	pcb->ssthresh = pcb->snd_wnd / 2;
tax	0:66300c77c6e9	1337	} else {
tax	0:66300c77c6e9	1338	pcb->ssthresh = pcb->cwnd / 2;
tax	0:66300c77c6e9	1339	}
tax	0:66300c77c6e9	1340
tax	0:66300c77c6e9	1341	/* The minimum value for ssthresh should be 2 MSS */
tax	0:66300c77c6e9	1342	if (pcb->ssthresh < 2*pcb->mss) {
tax	0:66300c77c6e9	1343	LWIP_DEBUGF(TCP_FR_DEBUG,
tax	0:66300c77c6e9	1344	("tcp_receive: The minimum value for ssthresh %"U16_F
tax	0:66300c77c6e9	1345	" should be min 2 mss %"U16_F"...\n",
tax	0:66300c77c6e9	1346	pcb->ssthresh, 2*pcb->mss));
tax	0:66300c77c6e9	1347	pcb->ssthresh = 2*pcb->mss;
tax	0:66300c77c6e9	1348	}
tax	0:66300c77c6e9	1349
tax	0:66300c77c6e9	1350	pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
tax	0:66300c77c6e9	1351	pcb->flags \|= TF_INFR;
tax	0:66300c77c6e9	1352	}
tax	0:66300c77c6e9	1353	}
tax	0:66300c77c6e9	1354
tax	0:66300c77c6e9	1355
tax	0:66300c77c6e9	1356	/**
tax	0:66300c77c6e9	1357	* Send keepalive packets to keep a connection active although
tax	0:66300c77c6e9	1358	* no data is sent over it.
tax	0:66300c77c6e9	1359	*
tax	0:66300c77c6e9	1360	* Called by tcp_slowtmr()
tax	0:66300c77c6e9	1361	*
tax	0:66300c77c6e9	1362	* @param pcb the tcp_pcb for which to send a keepalive packet
tax	0:66300c77c6e9	1363	*/
tax	0:66300c77c6e9	1364	void
tax	0:66300c77c6e9	1365	tcp_keepalive(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	1366	{
tax	0:66300c77c6e9	1367	struct pbuf *p;
tax	0:66300c77c6e9	1368	struct tcp_hdr *tcphdr;
tax	0:66300c77c6e9	1369
tax	0:66300c77c6e9	1370	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
tax	0:66300c77c6e9	1371	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
tax	0:66300c77c6e9	1372	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
tax	0:66300c77c6e9	1373
tax	0:66300c77c6e9	1374	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
tax	0:66300c77c6e9	1375	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
tax	0:66300c77c6e9	1376
tax	0:66300c77c6e9	1377	p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
tax	0:66300c77c6e9	1378	if(p == NULL) {
tax	0:66300c77c6e9	1379	LWIP_DEBUGF(TCP_DEBUG,
tax	0:66300c77c6e9	1380	("tcp_keepalive: could not allocate memory for pbuf\n"));
tax	0:66300c77c6e9	1381	return;
tax	0:66300c77c6e9	1382	}
tax	0:66300c77c6e9	1383	tcphdr = (struct tcp_hdr *)p->payload;
tax	0:66300c77c6e9	1384
tax	0:66300c77c6e9	1385	#if CHECKSUM_GEN_TCP
tax	0:66300c77c6e9	1386	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
tax	0:66300c77c6e9	1387	IP_PROTO_TCP, p->tot_len);
tax	0:66300c77c6e9	1388	#endif
tax	0:66300c77c6e9	1389	TCP_STATS_INC(tcp.xmit);
tax	0:66300c77c6e9	1390
tax	0:66300c77c6e9	1391	/* Send output to IP */
tax	0:66300c77c6e9	1392	#if LWIP_NETIF_HWADDRHINT
tax	0:66300c77c6e9	1393	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
tax	0:66300c77c6e9	1394	&(pcb->addr_hint));
tax	0:66300c77c6e9	1395	#else /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1396	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
tax	0:66300c77c6e9	1397	#endif /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1398
tax	0:66300c77c6e9	1399	pbuf_free(p);
tax	0:66300c77c6e9	1400
tax	0:66300c77c6e9	1401	LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
tax	0:66300c77c6e9	1402	pcb->snd_nxt - 1, pcb->rcv_nxt));
tax	0:66300c77c6e9	1403	}
tax	0:66300c77c6e9	1404
tax	0:66300c77c6e9	1405
tax	0:66300c77c6e9	1406	/**
tax	0:66300c77c6e9	1407	* Send persist timer zero-window probes to keep a connection active
tax	0:66300c77c6e9	1408	* when a window update is lost.
tax	0:66300c77c6e9	1409	*
tax	0:66300c77c6e9	1410	* Called by tcp_slowtmr()
tax	0:66300c77c6e9	1411	*
tax	0:66300c77c6e9	1412	* @param pcb the tcp_pcb for which to send a zero-window probe packet
tax	0:66300c77c6e9	1413	*/
tax	0:66300c77c6e9	1414	void
tax	0:66300c77c6e9	1415	tcp_zero_window_probe(struct tcp_pcb *pcb)
tax	0:66300c77c6e9	1416	{
tax	0:66300c77c6e9	1417	struct pbuf *p;
tax	0:66300c77c6e9	1418	struct tcp_hdr *tcphdr;
tax	0:66300c77c6e9	1419	struct tcp_seg *seg;
tax	0:66300c77c6e9	1420	u16_t len;
tax	0:66300c77c6e9	1421	u8_t is_fin;
tax	0:66300c77c6e9	1422
tax	0:66300c77c6e9	1423	LWIP_DEBUGF(TCP_DEBUG,
tax	0:66300c77c6e9	1424	("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
tax	0:66300c77c6e9	1425	U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
tax	0:66300c77c6e9	1426	ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
tax	0:66300c77c6e9	1427	ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
tax	0:66300c77c6e9	1428
tax	0:66300c77c6e9	1429	LWIP_DEBUGF(TCP_DEBUG,
tax	0:66300c77c6e9	1430	("tcp_zero_window_probe: tcp_ticks %"U32_F
tax	0:66300c77c6e9	1431	" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
tax	0:66300c77c6e9	1432	tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
tax	0:66300c77c6e9	1433
tax	0:66300c77c6e9	1434	seg = pcb->unacked;
tax	0:66300c77c6e9	1435
tax	0:66300c77c6e9	1436	if(seg == NULL) {
tax	0:66300c77c6e9	1437	seg = pcb->unsent;
tax	0:66300c77c6e9	1438	}
tax	0:66300c77c6e9	1439	if(seg == NULL) {
tax	0:66300c77c6e9	1440	return;
tax	0:66300c77c6e9	1441	}
tax	0:66300c77c6e9	1442
tax	0:66300c77c6e9	1443	is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
tax	0:66300c77c6e9	1444	/* we want to send one seqno: either FIN or data (no options) */
tax	0:66300c77c6e9	1445	len = is_fin ? 0 : 1;
tax	0:66300c77c6e9	1446
tax	0:66300c77c6e9	1447	p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
tax	0:66300c77c6e9	1448	if(p == NULL) {
tax	0:66300c77c6e9	1449	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
tax	0:66300c77c6e9	1450	return;
tax	0:66300c77c6e9	1451	}
tax	0:66300c77c6e9	1452	tcphdr = (struct tcp_hdr *)p->payload;
tax	0:66300c77c6e9	1453
tax	0:66300c77c6e9	1454	if (is_fin) {
tax	0:66300c77c6e9	1455	/* FIN segment, no data */
tax	0:66300c77c6e9	1456	TCPH_FLAGS_SET(tcphdr, TCP_ACK \| TCP_FIN);
tax	0:66300c77c6e9	1457	} else {
tax	0:66300c77c6e9	1458	/* Data segment, copy in one byte from the head of the unacked queue */
tax	0:66300c77c6e9	1459	((char )p->payload + TCP_HLEN) = (char )seg->dataptr;
tax	0:66300c77c6e9	1460	}
tax	0:66300c77c6e9	1461
tax	0:66300c77c6e9	1462	#if CHECKSUM_GEN_TCP
tax	0:66300c77c6e9	1463	tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
tax	0:66300c77c6e9	1464	IP_PROTO_TCP, p->tot_len);
tax	0:66300c77c6e9	1465	#endif
tax	0:66300c77c6e9	1466	TCP_STATS_INC(tcp.xmit);
tax	0:66300c77c6e9	1467
tax	0:66300c77c6e9	1468	/* Send output to IP */
tax	0:66300c77c6e9	1469	#if LWIP_NETIF_HWADDRHINT
tax	0:66300c77c6e9	1470	ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
tax	0:66300c77c6e9	1471	&(pcb->addr_hint));
tax	0:66300c77c6e9	1472	#else /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1473	ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
tax	0:66300c77c6e9	1474	#endif /* LWIP_NETIF_HWADDRHINT*/
tax	0:66300c77c6e9	1475
tax	0:66300c77c6e9	1476	pbuf_free(p);
tax	0:66300c77c6e9	1477
tax	0:66300c77c6e9	1478	LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
tax	0:66300c77c6e9	1479	" ackno %"U32_F".\n",
tax	0:66300c77c6e9	1480	pcb->snd_nxt - 1, pcb->rcv_nxt));
tax	0:66300c77c6e9	1481	}
tax	0:66300c77c6e9	1482	#endif /* LWIP_TCP */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	29 Mar 2011
Imports:	16
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	2

lwip/core/tcp_out.c@0:66300c77c6e9, 2011-03-29 (annotated)

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