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lwip/core/tcp_in.c@0:281d6ff68967, 2010-11-19 (annotated)

Committer:: hexley
Date:: Fri Nov 19 01:54:45 2010 +0000
Revision:: 0:281d6ff68967

Who changed what in which revision?

User	Revision	Line number	New contents of line
hexley	0:281d6ff68967	1	/**
hexley	0:281d6ff68967	2	* @file
hexley	0:281d6ff68967	3	* Transmission Control Protocol, incoming traffic
hexley	0:281d6ff68967	4	*
hexley	0:281d6ff68967	5	* The input processing functions of the TCP layer.
hexley	0:281d6ff68967	6	*
hexley	0:281d6ff68967	7	* These functions are generally called in the order (ip_input() ->)
hexley	0:281d6ff68967	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
hexley	0:281d6ff68967	9	*
hexley	0:281d6ff68967	10	*/
hexley	0:281d6ff68967	11
hexley	0:281d6ff68967	12	/*
hexley	0:281d6ff68967	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
hexley	0:281d6ff68967	14	* All rights reserved.
hexley	0:281d6ff68967	15	*
hexley	0:281d6ff68967	16	* Redistribution and use in source and binary forms, with or without modification,
hexley	0:281d6ff68967	17	* are permitted provided that the following conditions are met:
hexley	0:281d6ff68967	18	*
hexley	0:281d6ff68967	19	* 1. Redistributions of source code must retain the above copyright notice,
hexley	0:281d6ff68967	20	* this list of conditions and the following disclaimer.
hexley	0:281d6ff68967	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
hexley	0:281d6ff68967	22	* this list of conditions and the following disclaimer in the documentation
hexley	0:281d6ff68967	23	* and/or other materials provided with the distribution.
hexley	0:281d6ff68967	24	* 3. The name of the author may not be used to endorse or promote products
hexley	0:281d6ff68967	25	* derived from this software without specific prior written permission.
hexley	0:281d6ff68967	26	*
hexley	0:281d6ff68967	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
hexley	0:281d6ff68967	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
hexley	0:281d6ff68967	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
hexley	0:281d6ff68967	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
hexley	0:281d6ff68967	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
hexley	0:281d6ff68967	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
hexley	0:281d6ff68967	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
hexley	0:281d6ff68967	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
hexley	0:281d6ff68967	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
hexley	0:281d6ff68967	36	* OF SUCH DAMAGE.
hexley	0:281d6ff68967	37	*
hexley	0:281d6ff68967	38	* This file is part of the lwIP TCP/IP stack.
hexley	0:281d6ff68967	39	*
hexley	0:281d6ff68967	40	* Author: Adam Dunkels <adam@sics.se>
hexley	0:281d6ff68967	41	*
hexley	0:281d6ff68967	42	*/
hexley	0:281d6ff68967	43
hexley	0:281d6ff68967	44	#include "lwip/opt.h"
hexley	0:281d6ff68967	45
hexley	0:281d6ff68967	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
hexley	0:281d6ff68967	47
hexley	0:281d6ff68967	48	#include "lwip/tcp_impl.h"
hexley	0:281d6ff68967	49	#include "lwip/def.h"
hexley	0:281d6ff68967	50	#include "lwip/ip_addr.h"
hexley	0:281d6ff68967	51	#include "lwip/netif.h"
hexley	0:281d6ff68967	52	#include "lwip/mem.h"
hexley	0:281d6ff68967	53	#include "lwip/memp.h"
hexley	0:281d6ff68967	54	#include "lwip/inet_chksum.h"
hexley	0:281d6ff68967	55	#include "lwip/stats.h"
hexley	0:281d6ff68967	56	#include "lwip/snmp.h"
hexley	0:281d6ff68967	57	#include "arch/perf.h"
hexley	0:281d6ff68967	58
hexley	0:281d6ff68967	59	/* These variables are global to all functions involved in the input
hexley	0:281d6ff68967	60	processing of TCP segments. They are set by the tcp_input()
hexley	0:281d6ff68967	61	function. */
hexley	0:281d6ff68967	62	static struct tcp_seg inseg;
hexley	0:281d6ff68967	63	static struct tcp_hdr *tcphdr;
hexley	0:281d6ff68967	64	static struct ip_hdr *iphdr;
hexley	0:281d6ff68967	65	static u32_t seqno, ackno;
hexley	0:281d6ff68967	66	static u8_t flags;
hexley	0:281d6ff68967	67	static u16_t tcplen;
hexley	0:281d6ff68967	68
hexley	0:281d6ff68967	69	static u8_t recv_flags;
hexley	0:281d6ff68967	70	static struct pbuf *recv_data;
hexley	0:281d6ff68967	71
hexley	0:281d6ff68967	72	struct tcp_pcb *tcp_input_pcb;
hexley	0:281d6ff68967	73
hexley	0:281d6ff68967	74	/* Forward declarations. */
hexley	0:281d6ff68967	75	static err_t tcp_process(struct tcp_pcb *pcb);
hexley	0:281d6ff68967	76	static void tcp_receive(struct tcp_pcb *pcb);
hexley	0:281d6ff68967	77	static void tcp_parseopt(struct tcp_pcb *pcb);
hexley	0:281d6ff68967	78
hexley	0:281d6ff68967	79	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
hexley	0:281d6ff68967	80	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
hexley	0:281d6ff68967	81
hexley	0:281d6ff68967	82	/**
hexley	0:281d6ff68967	83	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
hexley	0:281d6ff68967	84	* the segment between the PCBs and passes it on to tcp_process(), which implements
hexley	0:281d6ff68967	85	* the TCP finite state machine. This function is called by the IP layer (in
hexley	0:281d6ff68967	86	* ip_input()).
hexley	0:281d6ff68967	87	*
hexley	0:281d6ff68967	88	* @param p received TCP segment to process (p->payload pointing to the IP header)
hexley	0:281d6ff68967	89	* @param inp network interface on which this segment was received
hexley	0:281d6ff68967	90	*/
hexley	0:281d6ff68967	91	void
hexley	0:281d6ff68967	92	tcp_input(struct pbuf p, struct netif inp)
hexley	0:281d6ff68967	93	{
hexley	0:281d6ff68967	94	struct tcp_pcb pcb, prev;
hexley	0:281d6ff68967	95	struct tcp_pcb_listen *lpcb;
hexley	0:281d6ff68967	96	#if SO_REUSE
hexley	0:281d6ff68967	97	struct tcp_pcb *lpcb_prev = NULL;
hexley	0:281d6ff68967	98	struct tcp_pcb_listen *lpcb_any = NULL;
hexley	0:281d6ff68967	99	#endif /* SO_REUSE */
hexley	0:281d6ff68967	100	u8_t hdrlen;
hexley	0:281d6ff68967	101	err_t err;
hexley	0:281d6ff68967	102
hexley	0:281d6ff68967	103	PERF_START;
hexley	0:281d6ff68967	104
hexley	0:281d6ff68967	105	TCP_STATS_INC(tcp.recv);
hexley	0:281d6ff68967	106	snmp_inc_tcpinsegs();
hexley	0:281d6ff68967	107
hexley	0:281d6ff68967	108	iphdr = (struct ip_hdr *)p->payload;
hexley	0:281d6ff68967	109	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
hexley	0:281d6ff68967	110
hexley	0:281d6ff68967	111	#if TCP_INPUT_DEBUG
hexley	0:281d6ff68967	112	tcp_debug_print(tcphdr);
hexley	0:281d6ff68967	113	#endif
hexley	0:281d6ff68967	114
hexley	0:281d6ff68967	115	/* remove header from payload */
hexley	0:281d6ff68967	116	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
hexley	0:281d6ff68967	117	/* drop short packets */
hexley	0:281d6ff68967	118	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
hexley	0:281d6ff68967	119	TCP_STATS_INC(tcp.lenerr);
hexley	0:281d6ff68967	120	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	121	snmp_inc_tcpinerrs();
hexley	0:281d6ff68967	122	pbuf_free(p);
hexley	0:281d6ff68967	123	return;
hexley	0:281d6ff68967	124	}
hexley	0:281d6ff68967	125
hexley	0:281d6ff68967	126	/* Don't even process incoming broadcasts/multicasts. */
hexley	0:281d6ff68967	127	if (ip_addr_isbroadcast(&current_iphdr_dest, inp) \|\|
hexley	0:281d6ff68967	128	ip_addr_ismulticast(&current_iphdr_dest)) {
hexley	0:281d6ff68967	129	TCP_STATS_INC(tcp.proterr);
hexley	0:281d6ff68967	130	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	131	snmp_inc_tcpinerrs();
hexley	0:281d6ff68967	132	pbuf_free(p);
hexley	0:281d6ff68967	133	return;
hexley	0:281d6ff68967	134	}
hexley	0:281d6ff68967	135
hexley	0:281d6ff68967	136	#if CHECKSUM_CHECK_TCP
hexley	0:281d6ff68967	137	/* Verify TCP checksum. */
hexley	0:281d6ff68967	138	if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
hexley	0:281d6ff68967	139	IP_PROTO_TCP, p->tot_len) != 0) {
hexley	0:281d6ff68967	140	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
hexley	0:281d6ff68967	141	inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
hexley	0:281d6ff68967	142	IP_PROTO_TCP, p->tot_len)));
hexley	0:281d6ff68967	143	#if TCP_DEBUG
hexley	0:281d6ff68967	144	tcp_debug_print(tcphdr);
hexley	0:281d6ff68967	145	#endif /* TCP_DEBUG */
hexley	0:281d6ff68967	146	TCP_STATS_INC(tcp.chkerr);
hexley	0:281d6ff68967	147	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	148	snmp_inc_tcpinerrs();
hexley	0:281d6ff68967	149	pbuf_free(p);
hexley	0:281d6ff68967	150	return;
hexley	0:281d6ff68967	151	}
hexley	0:281d6ff68967	152	#endif
hexley	0:281d6ff68967	153
hexley	0:281d6ff68967	154	/* Move the payload pointer in the pbuf so that it points to the
hexley	0:281d6ff68967	155	TCP data instead of the TCP header. */
hexley	0:281d6ff68967	156	hdrlen = TCPH_HDRLEN(tcphdr);
hexley	0:281d6ff68967	157	if(pbuf_header(p, -(hdrlen * 4))){
hexley	0:281d6ff68967	158	/* drop short packets */
hexley	0:281d6ff68967	159	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
hexley	0:281d6ff68967	160	TCP_STATS_INC(tcp.lenerr);
hexley	0:281d6ff68967	161	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	162	snmp_inc_tcpinerrs();
hexley	0:281d6ff68967	163	pbuf_free(p);
hexley	0:281d6ff68967	164	return;
hexley	0:281d6ff68967	165	}
hexley	0:281d6ff68967	166
hexley	0:281d6ff68967	167	/* Convert fields in TCP header to host byte order. */
hexley	0:281d6ff68967	168	tcphdr->src = ntohs(tcphdr->src);
hexley	0:281d6ff68967	169	tcphdr->dest = ntohs(tcphdr->dest);
hexley	0:281d6ff68967	170	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
hexley	0:281d6ff68967	171	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
hexley	0:281d6ff68967	172	tcphdr->wnd = ntohs(tcphdr->wnd);
hexley	0:281d6ff68967	173
hexley	0:281d6ff68967	174	flags = TCPH_FLAGS(tcphdr);
hexley	0:281d6ff68967	175	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
hexley	0:281d6ff68967	176
hexley	0:281d6ff68967	177	/* Demultiplex an incoming segment. First, we check if it is destined
hexley	0:281d6ff68967	178	for an active connection. */
hexley	0:281d6ff68967	179	prev = NULL;
hexley	0:281d6ff68967	180
hexley	0:281d6ff68967	181
hexley	0:281d6ff68967	182	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
hexley	0:281d6ff68967	183	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
hexley	0:281d6ff68967	184	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
hexley	0:281d6ff68967	185	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
hexley	0:281d6ff68967	186	if (pcb->remote_port == tcphdr->src &&
hexley	0:281d6ff68967	187	pcb->local_port == tcphdr->dest &&
hexley	0:281d6ff68967	188	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
hexley	0:281d6ff68967	189	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
hexley	0:281d6ff68967	190
hexley	0:281d6ff68967	191	/* Move this PCB to the front of the list so that subsequent
hexley	0:281d6ff68967	192	lookups will be faster (we exploit locality in TCP segment
hexley	0:281d6ff68967	193	arrivals). */
hexley	0:281d6ff68967	194	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
hexley	0:281d6ff68967	195	if (prev != NULL) {
hexley	0:281d6ff68967	196	prev->next = pcb->next;
hexley	0:281d6ff68967	197	pcb->next = tcp_active_pcbs;
hexley	0:281d6ff68967	198	tcp_active_pcbs = pcb;
hexley	0:281d6ff68967	199	}
hexley	0:281d6ff68967	200	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
hexley	0:281d6ff68967	201	break;
hexley	0:281d6ff68967	202	}
hexley	0:281d6ff68967	203	prev = pcb;
hexley	0:281d6ff68967	204	}
hexley	0:281d6ff68967	205
hexley	0:281d6ff68967	206	if (pcb == NULL) {
hexley	0:281d6ff68967	207	/* If it did not go to an active connection, we check the connections
hexley	0:281d6ff68967	208	in the TIME-WAIT state. */
hexley	0:281d6ff68967	209	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
hexley	0:281d6ff68967	210	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
hexley	0:281d6ff68967	211	if (pcb->remote_port == tcphdr->src &&
hexley	0:281d6ff68967	212	pcb->local_port == tcphdr->dest &&
hexley	0:281d6ff68967	213	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
hexley	0:281d6ff68967	214	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
hexley	0:281d6ff68967	215	/* We don't really care enough to move this PCB to the front
hexley	0:281d6ff68967	216	of the list since we are not very likely to receive that
hexley	0:281d6ff68967	217	many segments for connections in TIME-WAIT. */
hexley	0:281d6ff68967	218	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
hexley	0:281d6ff68967	219	tcp_timewait_input(pcb);
hexley	0:281d6ff68967	220	pbuf_free(p);
hexley	0:281d6ff68967	221	return;
hexley	0:281d6ff68967	222	}
hexley	0:281d6ff68967	223	}
hexley	0:281d6ff68967	224
hexley	0:281d6ff68967	225	/* Finally, if we still did not get a match, we check all PCBs that
hexley	0:281d6ff68967	226	are LISTENing for incoming connections. */
hexley	0:281d6ff68967	227	prev = NULL;
hexley	0:281d6ff68967	228	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
hexley	0:281d6ff68967	229	if (lpcb->local_port == tcphdr->dest) {
hexley	0:281d6ff68967	230	#if SO_REUSE
hexley	0:281d6ff68967	231	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
hexley	0:281d6ff68967	232	/* found an exact match */
hexley	0:281d6ff68967	233	break;
hexley	0:281d6ff68967	234	} else if(ip_addr_isany(&(lpcb->local_ip))) {
hexley	0:281d6ff68967	235	/* found an ANY-match */
hexley	0:281d6ff68967	236	lpcb_any = lpcb;
hexley	0:281d6ff68967	237	lpcb_prev = prev;
hexley	0:281d6ff68967	238	}
hexley	0:281d6ff68967	239	#else /* SO_REUSE */
hexley	0:281d6ff68967	240	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) \|\|
hexley	0:281d6ff68967	241	ip_addr_isany(&(lpcb->local_ip))) {
hexley	0:281d6ff68967	242	/* found a match */
hexley	0:281d6ff68967	243	break;
hexley	0:281d6ff68967	244	}
hexley	0:281d6ff68967	245	#endif /* SO_REUSE */
hexley	0:281d6ff68967	246	}
hexley	0:281d6ff68967	247	prev = (struct tcp_pcb *)lpcb;
hexley	0:281d6ff68967	248	}
hexley	0:281d6ff68967	249	#if SO_REUSE
hexley	0:281d6ff68967	250	/* first try specific local IP */
hexley	0:281d6ff68967	251	if (lpcb == NULL) {
hexley	0:281d6ff68967	252	/* only pass to ANY if no specific local IP has been found */
hexley	0:281d6ff68967	253	lpcb = lpcb_any;
hexley	0:281d6ff68967	254	prev = lpcb_prev;
hexley	0:281d6ff68967	255	}
hexley	0:281d6ff68967	256	#endif /* SO_REUSE */
hexley	0:281d6ff68967	257	if (lpcb != NULL) {
hexley	0:281d6ff68967	258	/* Move this PCB to the front of the list so that subsequent
hexley	0:281d6ff68967	259	lookups will be faster (we exploit locality in TCP segment
hexley	0:281d6ff68967	260	arrivals). */
hexley	0:281d6ff68967	261	if (prev != NULL) {
hexley	0:281d6ff68967	262	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
hexley	0:281d6ff68967	263	/* our successor is the remainder of the listening list */
hexley	0:281d6ff68967	264	lpcb->next = tcp_listen_pcbs.listen_pcbs;
hexley	0:281d6ff68967	265	/* put this listening pcb at the head of the listening list */
hexley	0:281d6ff68967	266	tcp_listen_pcbs.listen_pcbs = lpcb;
hexley	0:281d6ff68967	267	}
hexley	0:281d6ff68967	268
hexley	0:281d6ff68967	269	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
hexley	0:281d6ff68967	270	tcp_listen_input(lpcb);
hexley	0:281d6ff68967	271	pbuf_free(p);
hexley	0:281d6ff68967	272	return;
hexley	0:281d6ff68967	273	}
hexley	0:281d6ff68967	274	}
hexley	0:281d6ff68967	275
hexley	0:281d6ff68967	276	#if TCP_INPUT_DEBUG
hexley	0:281d6ff68967	277	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
hexley	0:281d6ff68967	278	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
hexley	0:281d6ff68967	279	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
hexley	0:281d6ff68967	280	#endif /* TCP_INPUT_DEBUG */
hexley	0:281d6ff68967	281
hexley	0:281d6ff68967	282
hexley	0:281d6ff68967	283	if (pcb != NULL) {
hexley	0:281d6ff68967	284	/* The incoming segment belongs to a connection. */
hexley	0:281d6ff68967	285	#if TCP_INPUT_DEBUG
hexley	0:281d6ff68967	286	#if TCP_DEBUG
hexley	0:281d6ff68967	287	tcp_debug_print_state(pcb->state);
hexley	0:281d6ff68967	288	#endif /* TCP_DEBUG */
hexley	0:281d6ff68967	289	#endif /* TCP_INPUT_DEBUG */
hexley	0:281d6ff68967	290
hexley	0:281d6ff68967	291	/* Set up a tcp_seg structure. */
hexley	0:281d6ff68967	292	inseg.next = NULL;
hexley	0:281d6ff68967	293	inseg.len = p->tot_len;
hexley	0:281d6ff68967	294	inseg.dataptr = p->payload;
hexley	0:281d6ff68967	295	inseg.p = p;
hexley	0:281d6ff68967	296	inseg.tcphdr = tcphdr;
hexley	0:281d6ff68967	297
hexley	0:281d6ff68967	298	recv_data = NULL;
hexley	0:281d6ff68967	299	recv_flags = 0;
hexley	0:281d6ff68967	300
hexley	0:281d6ff68967	301	/* If there is data which was previously "refused" by upper layer */
hexley	0:281d6ff68967	302	if (pcb->refused_data != NULL) {
hexley	0:281d6ff68967	303	/* Notify again application with data previously received. */
hexley	0:281d6ff68967	304	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
hexley	0:281d6ff68967	305	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
hexley	0:281d6ff68967	306	if (err == ERR_OK) {
hexley	0:281d6ff68967	307	pcb->refused_data = NULL;
hexley	0:281d6ff68967	308	} else {
hexley	0:281d6ff68967	309	/* if err == ERR_ABRT, 'pcb' is already deallocated */
hexley	0:281d6ff68967	310	/* drop incoming packets, because pcb is "full" */
hexley	0:281d6ff68967	311	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
hexley	0:281d6ff68967	312	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	313	snmp_inc_tcpinerrs();
hexley	0:281d6ff68967	314	pbuf_free(p);
hexley	0:281d6ff68967	315	return;
hexley	0:281d6ff68967	316	}
hexley	0:281d6ff68967	317	}
hexley	0:281d6ff68967	318	tcp_input_pcb = pcb;
hexley	0:281d6ff68967	319	err = tcp_process(pcb);
hexley	0:281d6ff68967	320	/* A return value of ERR_ABRT means that tcp_abort() was called
hexley	0:281d6ff68967	321	and that the pcb has been freed. If so, we don't do anything. */
hexley	0:281d6ff68967	322	if (err != ERR_ABRT) {
hexley	0:281d6ff68967	323	if (recv_flags & TF_RESET) {
hexley	0:281d6ff68967	324	/* TF_RESET means that the connection was reset by the other
hexley	0:281d6ff68967	325	end. We then call the error callback to inform the
hexley	0:281d6ff68967	326	application that the connection is dead before we
hexley	0:281d6ff68967	327	deallocate the PCB. */
hexley	0:281d6ff68967	328	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
hexley	0:281d6ff68967	329	tcp_pcb_remove(&tcp_active_pcbs, pcb);
hexley	0:281d6ff68967	330	memp_free(MEMP_TCP_PCB, pcb);
hexley	0:281d6ff68967	331	} else if (recv_flags & TF_CLOSED) {
hexley	0:281d6ff68967	332	/* The connection has been closed and we will deallocate the
hexley	0:281d6ff68967	333	PCB. */
hexley	0:281d6ff68967	334	tcp_pcb_remove(&tcp_active_pcbs, pcb);
hexley	0:281d6ff68967	335	memp_free(MEMP_TCP_PCB, pcb);
hexley	0:281d6ff68967	336	} else {
hexley	0:281d6ff68967	337	err = ERR_OK;
hexley	0:281d6ff68967	338	/* If the application has registered a "sent" function to be
hexley	0:281d6ff68967	339	called when new send buffer space is available, we call it
hexley	0:281d6ff68967	340	now. */
hexley	0:281d6ff68967	341	if (pcb->acked > 0) {
hexley	0:281d6ff68967	342	TCP_EVENT_SENT(pcb, pcb->acked, err);
hexley	0:281d6ff68967	343	if (err == ERR_ABRT) {
hexley	0:281d6ff68967	344	goto aborted;
hexley	0:281d6ff68967	345	}
hexley	0:281d6ff68967	346	}
hexley	0:281d6ff68967	347
hexley	0:281d6ff68967	348	if (recv_data != NULL) {
hexley	0:281d6ff68967	349	if (pcb->flags & TF_RXCLOSED) {
hexley	0:281d6ff68967	350	/* received data although already closed -> abort (send RST) to
hexley	0:281d6ff68967	351	notify the remote host that not all data has been processed */
hexley	0:281d6ff68967	352	pbuf_free(recv_data);
hexley	0:281d6ff68967	353	tcp_abort(pcb);
hexley	0:281d6ff68967	354	goto aborted;
hexley	0:281d6ff68967	355	}
hexley	0:281d6ff68967	356	if (flags & TCP_PSH) {
hexley	0:281d6ff68967	357	recv_data->flags \|= PBUF_FLAG_PUSH;
hexley	0:281d6ff68967	358	}
hexley	0:281d6ff68967	359
hexley	0:281d6ff68967	360	/* Notify application that data has been received. */
hexley	0:281d6ff68967	361	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
hexley	0:281d6ff68967	362	if (err == ERR_ABRT) {
hexley	0:281d6ff68967	363	goto aborted;
hexley	0:281d6ff68967	364	}
hexley	0:281d6ff68967	365
hexley	0:281d6ff68967	366	/* If the upper layer can't receive this data, store it */
hexley	0:281d6ff68967	367	if (err != ERR_OK) {
hexley	0:281d6ff68967	368	pcb->refused_data = recv_data;
hexley	0:281d6ff68967	369	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
hexley	0:281d6ff68967	370	}
hexley	0:281d6ff68967	371	}
hexley	0:281d6ff68967	372
hexley	0:281d6ff68967	373	/* If a FIN segment was received, we call the callback
hexley	0:281d6ff68967	374	function with a NULL buffer to indicate EOF. */
hexley	0:281d6ff68967	375	if (recv_flags & TF_GOT_FIN) {
hexley	0:281d6ff68967	376	/* correct rcv_wnd as the application won't call tcp_recved()
hexley	0:281d6ff68967	377	for the FIN's seqno */
hexley	0:281d6ff68967	378	if (pcb->rcv_wnd != TCP_WND) {
hexley	0:281d6ff68967	379	pcb->rcv_wnd++;
hexley	0:281d6ff68967	380	}
hexley	0:281d6ff68967	381	TCP_EVENT_CLOSED(pcb, err);
hexley	0:281d6ff68967	382	if (err == ERR_ABRT) {
hexley	0:281d6ff68967	383	goto aborted;
hexley	0:281d6ff68967	384	}
hexley	0:281d6ff68967	385	}
hexley	0:281d6ff68967	386
hexley	0:281d6ff68967	387	tcp_input_pcb = NULL;
hexley	0:281d6ff68967	388	/* Try to send something out. */
hexley	0:281d6ff68967	389	tcp_output(pcb);
hexley	0:281d6ff68967	390	#if TCP_INPUT_DEBUG
hexley	0:281d6ff68967	391	#if TCP_DEBUG
hexley	0:281d6ff68967	392	tcp_debug_print_state(pcb->state);
hexley	0:281d6ff68967	393	#endif /* TCP_DEBUG */
hexley	0:281d6ff68967	394	#endif /* TCP_INPUT_DEBUG */
hexley	0:281d6ff68967	395	}
hexley	0:281d6ff68967	396	}
hexley	0:281d6ff68967	397	/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
hexley	0:281d6ff68967	398	Below this line, 'pcb' may not be dereferenced! */
hexley	0:281d6ff68967	399	aborted:
hexley	0:281d6ff68967	400	tcp_input_pcb = NULL;
hexley	0:281d6ff68967	401	recv_data = NULL;
hexley	0:281d6ff68967	402
hexley	0:281d6ff68967	403	/* give up our reference to inseg.p */
hexley	0:281d6ff68967	404	if (inseg.p != NULL)
hexley	0:281d6ff68967	405	{
hexley	0:281d6ff68967	406	pbuf_free(inseg.p);
hexley	0:281d6ff68967	407	inseg.p = NULL;
hexley	0:281d6ff68967	408	}
hexley	0:281d6ff68967	409	} else {
hexley	0:281d6ff68967	410
hexley	0:281d6ff68967	411	/* If no matching PCB was found, send a TCP RST (reset) to the
hexley	0:281d6ff68967	412	sender. */
hexley	0:281d6ff68967	413	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
hexley	0:281d6ff68967	414	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
hexley	0:281d6ff68967	415	TCP_STATS_INC(tcp.proterr);
hexley	0:281d6ff68967	416	TCP_STATS_INC(tcp.drop);
hexley	0:281d6ff68967	417	tcp_rst(ackno, seqno + tcplen,
hexley	0:281d6ff68967	418	ip_current_dest_addr(), ip_current_src_addr(),
hexley	0:281d6ff68967	419	tcphdr->dest, tcphdr->src);
hexley	0:281d6ff68967	420	}
hexley	0:281d6ff68967	421	pbuf_free(p);
hexley	0:281d6ff68967	422	}
hexley	0:281d6ff68967	423
hexley	0:281d6ff68967	424	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
hexley	0:281d6ff68967	425	PERF_STOP("tcp_input");
hexley	0:281d6ff68967	426	}
hexley	0:281d6ff68967	427
hexley	0:281d6ff68967	428	/**
hexley	0:281d6ff68967	429	* Called by tcp_input() when a segment arrives for a listening
hexley	0:281d6ff68967	430	* connection (from tcp_input()).
hexley	0:281d6ff68967	431	*
hexley	0:281d6ff68967	432	* @param pcb the tcp_pcb_listen for which a segment arrived
hexley	0:281d6ff68967	433	* @return ERR_OK if the segment was processed
hexley	0:281d6ff68967	434	* another err_t on error
hexley	0:281d6ff68967	435	*
hexley	0:281d6ff68967	436	* @note the return value is not (yet?) used in tcp_input()
hexley	0:281d6ff68967	437	* @note the segment which arrived is saved in global variables, therefore only the pcb
hexley	0:281d6ff68967	438	* involved is passed as a parameter to this function
hexley	0:281d6ff68967	439	*/
hexley	0:281d6ff68967	440	static err_t
hexley	0:281d6ff68967	441	tcp_listen_input(struct tcp_pcb_listen *pcb)
hexley	0:281d6ff68967	442	{
hexley	0:281d6ff68967	443	struct tcp_pcb *npcb;
hexley	0:281d6ff68967	444	err_t rc;
hexley	0:281d6ff68967	445
hexley	0:281d6ff68967	446	/* In the LISTEN state, we check for incoming SYN segments,
hexley	0:281d6ff68967	447	creates a new PCB, and responds with a SYN\|ACK. */
hexley	0:281d6ff68967	448	if (flags & TCP_ACK) {
hexley	0:281d6ff68967	449	/* For incoming segments with the ACK flag set, respond with a
hexley	0:281d6ff68967	450	RST. */
hexley	0:281d6ff68967	451	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
hexley	0:281d6ff68967	452	tcp_rst(ackno + 1, seqno + tcplen,
hexley	0:281d6ff68967	453	ip_current_dest_addr(), ip_current_src_addr(),
hexley	0:281d6ff68967	454	tcphdr->dest, tcphdr->src);
hexley	0:281d6ff68967	455	} else if (flags & TCP_SYN) {
hexley	0:281d6ff68967	456	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
hexley	0:281d6ff68967	457	#if TCP_LISTEN_BACKLOG
hexley	0:281d6ff68967	458	if (pcb->accepts_pending >= pcb->backlog) {
hexley	0:281d6ff68967	459	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
hexley	0:281d6ff68967	460	return ERR_ABRT;
hexley	0:281d6ff68967	461	}
hexley	0:281d6ff68967	462	#endif /* TCP_LISTEN_BACKLOG */
hexley	0:281d6ff68967	463	npcb = tcp_alloc(pcb->prio);
hexley	0:281d6ff68967	464	/* If a new PCB could not be created (probably due to lack of memory),
hexley	0:281d6ff68967	465	we don't do anything, but rely on the sender will retransmit the
hexley	0:281d6ff68967	466	SYN at a time when we have more memory available. */
hexley	0:281d6ff68967	467	if (npcb == NULL) {
hexley	0:281d6ff68967	468	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
hexley	0:281d6ff68967	469	TCP_STATS_INC(tcp.memerr);
hexley	0:281d6ff68967	470	return ERR_MEM;
hexley	0:281d6ff68967	471	}
hexley	0:281d6ff68967	472	#if TCP_LISTEN_BACKLOG
hexley	0:281d6ff68967	473	pcb->accepts_pending++;
hexley	0:281d6ff68967	474	#endif /* TCP_LISTEN_BACKLOG */
hexley	0:281d6ff68967	475	/* Set up the new PCB. */
hexley	0:281d6ff68967	476	ip_addr_copy(npcb->local_ip, current_iphdr_dest);
hexley	0:281d6ff68967	477	npcb->local_port = pcb->local_port;
hexley	0:281d6ff68967	478	ip_addr_copy(npcb->remote_ip, current_iphdr_src);
hexley	0:281d6ff68967	479	npcb->remote_port = tcphdr->src;
hexley	0:281d6ff68967	480	npcb->state = SYN_RCVD;
hexley	0:281d6ff68967	481	npcb->rcv_nxt = seqno + 1;
hexley	0:281d6ff68967	482	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
hexley	0:281d6ff68967	483	npcb->snd_wnd = tcphdr->wnd;
hexley	0:281d6ff68967	484	npcb->ssthresh = npcb->snd_wnd;
hexley	0:281d6ff68967	485	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
hexley	0:281d6ff68967	486	npcb->callback_arg = pcb->callback_arg;
hexley	0:281d6ff68967	487	#if LWIP_CALLBACK_API
hexley	0:281d6ff68967	488	npcb->accept = pcb->accept;
hexley	0:281d6ff68967	489	#endif /* LWIP_CALLBACK_API */
hexley	0:281d6ff68967	490	/* inherit socket options */
hexley	0:281d6ff68967	491	npcb->so_options = pcb->so_options & SOF_INHERITED;
hexley	0:281d6ff68967	492	/* Register the new PCB so that we can begin receiving segments
hexley	0:281d6ff68967	493	for it. */
hexley	0:281d6ff68967	494	TCP_REG(&tcp_active_pcbs, npcb);
hexley	0:281d6ff68967	495
hexley	0:281d6ff68967	496	/* Parse any options in the SYN. */
hexley	0:281d6ff68967	497	tcp_parseopt(npcb);
hexley	0:281d6ff68967	498	#if TCP_CALCULATE_EFF_SEND_MSS
hexley	0:281d6ff68967	499	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
hexley	0:281d6ff68967	500	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
hexley	0:281d6ff68967	501
hexley	0:281d6ff68967	502	snmp_inc_tcppassiveopens();
hexley	0:281d6ff68967	503
hexley	0:281d6ff68967	504	/* Send a SYN\|ACK together with the MSS option. */
hexley	0:281d6ff68967	505	rc = tcp_enqueue_flags(npcb, TCP_SYN \| TCP_ACK);
hexley	0:281d6ff68967	506	if (rc != ERR_OK) {
hexley	0:281d6ff68967	507	tcp_abandon(npcb, 0);
hexley	0:281d6ff68967	508	return rc;
hexley	0:281d6ff68967	509	}
hexley	0:281d6ff68967	510	return tcp_output(npcb);
hexley	0:281d6ff68967	511	}
hexley	0:281d6ff68967	512	return ERR_OK;
hexley	0:281d6ff68967	513	}
hexley	0:281d6ff68967	514
hexley	0:281d6ff68967	515	/**
hexley	0:281d6ff68967	516	* Called by tcp_input() when a segment arrives for a connection in
hexley	0:281d6ff68967	517	* TIME_WAIT.
hexley	0:281d6ff68967	518	*
hexley	0:281d6ff68967	519	* @param pcb the tcp_pcb for which a segment arrived
hexley	0:281d6ff68967	520	*
hexley	0:281d6ff68967	521	* @note the segment which arrived is saved in global variables, therefore only the pcb
hexley	0:281d6ff68967	522	* involved is passed as a parameter to this function
hexley	0:281d6ff68967	523	*/
hexley	0:281d6ff68967	524	static err_t
hexley	0:281d6ff68967	525	tcp_timewait_input(struct tcp_pcb *pcb)
hexley	0:281d6ff68967	526	{
hexley	0:281d6ff68967	527	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
hexley	0:281d6ff68967	528	/* RFC 793 3.9 Event Processing - Segment Arrives:
hexley	0:281d6ff68967	529	* - first check sequence number - we skip that one in TIME_WAIT (always
hexley	0:281d6ff68967	530	* acceptable since we only send ACKs)
hexley	0:281d6ff68967	531	* - second check the RST bit (... return) */
hexley	0:281d6ff68967	532	if (flags & TCP_RST) {
hexley	0:281d6ff68967	533	return ERR_OK;
hexley	0:281d6ff68967	534	}
hexley	0:281d6ff68967	535	/* - fourth, check the SYN bit, */
hexley	0:281d6ff68967	536	if (flags & TCP_SYN) {
hexley	0:281d6ff68967	537	/* If an incoming segment is not acceptable, an acknowledgment
hexley	0:281d6ff68967	538	should be sent in reply */
hexley	0:281d6ff68967	539	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
hexley	0:281d6ff68967	540	/* If the SYN is in the window it is an error, send a reset */
hexley	0:281d6ff68967	541	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
hexley	0:281d6ff68967	542	tcphdr->dest, tcphdr->src);
hexley	0:281d6ff68967	543	return ERR_OK;
hexley	0:281d6ff68967	544	}
hexley	0:281d6ff68967	545	} else if (flags & TCP_FIN) {
hexley	0:281d6ff68967	546	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
hexley	0:281d6ff68967	547	Restart the 2 MSL time-wait timeout.*/
hexley	0:281d6ff68967	548	pcb->tmr = tcp_ticks;
hexley	0:281d6ff68967	549	}
hexley	0:281d6ff68967	550
hexley	0:281d6ff68967	551	if ((tcplen > 0)) {
hexley	0:281d6ff68967	552	/* Acknowledge data, FIN or out-of-window SYN */
hexley	0:281d6ff68967	553	pcb->flags \|= TF_ACK_NOW;
hexley	0:281d6ff68967	554	return tcp_output(pcb);
hexley	0:281d6ff68967	555	}
hexley	0:281d6ff68967	556	return ERR_OK;
hexley	0:281d6ff68967	557	}
hexley	0:281d6ff68967	558
hexley	0:281d6ff68967	559	/**
hexley	0:281d6ff68967	560	* Implements the TCP state machine. Called by tcp_input. In some
hexley	0:281d6ff68967	561	* states tcp_receive() is called to receive data. The tcp_seg
hexley	0:281d6ff68967	562	* argument will be freed by the caller (tcp_input()) unless the
hexley	0:281d6ff68967	563	* recv_data pointer in the pcb is set.
hexley	0:281d6ff68967	564	*
hexley	0:281d6ff68967	565	* @param pcb the tcp_pcb for which a segment arrived
hexley	0:281d6ff68967	566	*
hexley	0:281d6ff68967	567	* @note the segment which arrived is saved in global variables, therefore only the pcb
hexley	0:281d6ff68967	568	* involved is passed as a parameter to this function
hexley	0:281d6ff68967	569	*/
hexley	0:281d6ff68967	570	static err_t
hexley	0:281d6ff68967	571	tcp_process(struct tcp_pcb *pcb)
hexley	0:281d6ff68967	572	{
hexley	0:281d6ff68967	573	struct tcp_seg *rseg;
hexley	0:281d6ff68967	574	u8_t acceptable = 0;
hexley	0:281d6ff68967	575	err_t err;
hexley	0:281d6ff68967	576
hexley	0:281d6ff68967	577	err = ERR_OK;
hexley	0:281d6ff68967	578
hexley	0:281d6ff68967	579	/* Process incoming RST segments. */
hexley	0:281d6ff68967	580	if (flags & TCP_RST) {
hexley	0:281d6ff68967	581	/* First, determine if the reset is acceptable. */
hexley	0:281d6ff68967	582	if (pcb->state == SYN_SENT) {
hexley	0:281d6ff68967	583	if (ackno == pcb->snd_nxt) {
hexley	0:281d6ff68967	584	acceptable = 1;
hexley	0:281d6ff68967	585	}
hexley	0:281d6ff68967	586	} else {
hexley	0:281d6ff68967	587	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
hexley	0:281d6ff68967	588	pcb->rcv_nxt+pcb->rcv_wnd)) {
hexley	0:281d6ff68967	589	acceptable = 1;
hexley	0:281d6ff68967	590	}
hexley	0:281d6ff68967	591	}
hexley	0:281d6ff68967	592
hexley	0:281d6ff68967	593	if (acceptable) {
hexley	0:281d6ff68967	594	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
hexley	0:281d6ff68967	595	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
hexley	0:281d6ff68967	596	recv_flags \|= TF_RESET;
hexley	0:281d6ff68967	597	pcb->flags &= ~TF_ACK_DELAY;
hexley	0:281d6ff68967	598	return ERR_RST;
hexley	0:281d6ff68967	599	} else {
hexley	0:281d6ff68967	600	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
hexley	0:281d6ff68967	601	seqno, pcb->rcv_nxt));
hexley	0:281d6ff68967	602	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
hexley	0:281d6ff68967	603	seqno, pcb->rcv_nxt));
hexley	0:281d6ff68967	604	return ERR_OK;
hexley	0:281d6ff68967	605	}
hexley	0:281d6ff68967	606	}
hexley	0:281d6ff68967	607
hexley	0:281d6ff68967	608	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
hexley	0:281d6ff68967	609	/* Cope with new connection attempt after remote end crashed */
hexley	0:281d6ff68967	610	tcp_ack_now(pcb);
hexley	0:281d6ff68967	611	return ERR_OK;
hexley	0:281d6ff68967	612	}
hexley	0:281d6ff68967	613
hexley	0:281d6ff68967	614	if ((pcb->flags & TF_RXCLOSED) == 0) {
hexley	0:281d6ff68967	615	/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
hexley	0:281d6ff68967	616	pcb->tmr = tcp_ticks;
hexley	0:281d6ff68967	617	}
hexley	0:281d6ff68967	618	pcb->keep_cnt_sent = 0;
hexley	0:281d6ff68967	619
hexley	0:281d6ff68967	620	tcp_parseopt(pcb);
hexley	0:281d6ff68967	621
hexley	0:281d6ff68967	622	/* Do different things depending on the TCP state. */
hexley	0:281d6ff68967	623	switch (pcb->state) {
hexley	0:281d6ff68967	624	case SYN_SENT:
hexley	0:281d6ff68967	625	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
hexley	0:281d6ff68967	626	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
hexley	0:281d6ff68967	627	/* received SYN ACK with expected sequence number? */
hexley	0:281d6ff68967	628	if ((flags & TCP_ACK) && (flags & TCP_SYN)
hexley	0:281d6ff68967	629	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
hexley	0:281d6ff68967	630	pcb->snd_buf++;
hexley	0:281d6ff68967	631	pcb->rcv_nxt = seqno + 1;
hexley	0:281d6ff68967	632	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
hexley	0:281d6ff68967	633	pcb->lastack = ackno;
hexley	0:281d6ff68967	634	pcb->snd_wnd = tcphdr->wnd;
hexley	0:281d6ff68967	635	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
hexley	0:281d6ff68967	636	pcb->state = ESTABLISHED;
hexley	0:281d6ff68967	637
hexley	0:281d6ff68967	638	#if TCP_CALCULATE_EFF_SEND_MSS
hexley	0:281d6ff68967	639	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
hexley	0:281d6ff68967	640	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
hexley	0:281d6ff68967	641
hexley	0:281d6ff68967	642	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
hexley	0:281d6ff68967	643	* but for the default value of pcb->mss) */
hexley	0:281d6ff68967	644	pcb->ssthresh = pcb->mss * 10;
hexley	0:281d6ff68967	645
hexley	0:281d6ff68967	646	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
hexley	0:281d6ff68967	647	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
hexley	0:281d6ff68967	648	--pcb->snd_queuelen;
hexley	0:281d6ff68967	649	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
hexley	0:281d6ff68967	650	rseg = pcb->unacked;
hexley	0:281d6ff68967	651	pcb->unacked = rseg->next;
hexley	0:281d6ff68967	652
hexley	0:281d6ff68967	653	/* If there's nothing left to acknowledge, stop the retransmit
hexley	0:281d6ff68967	654	timer, otherwise reset it to start again */
hexley	0:281d6ff68967	655	if(pcb->unacked == NULL)
hexley	0:281d6ff68967	656	pcb->rtime = -1;
hexley	0:281d6ff68967	657	else {
hexley	0:281d6ff68967	658	pcb->rtime = 0;
hexley	0:281d6ff68967	659	pcb->nrtx = 0;
hexley	0:281d6ff68967	660	}
hexley	0:281d6ff68967	661
hexley	0:281d6ff68967	662	tcp_seg_free(rseg);
hexley	0:281d6ff68967	663
hexley	0:281d6ff68967	664	/* Call the user specified function to call when sucessfully
hexley	0:281d6ff68967	665	* connected. */
hexley	0:281d6ff68967	666	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
hexley	0:281d6ff68967	667	if (err == ERR_ABRT) {
hexley	0:281d6ff68967	668	return ERR_ABRT;
hexley	0:281d6ff68967	669	}
hexley	0:281d6ff68967	670	tcp_ack_now(pcb);
hexley	0:281d6ff68967	671	}
hexley	0:281d6ff68967	672	/* received ACK? possibly a half-open connection */
hexley	0:281d6ff68967	673	else if (flags & TCP_ACK) {
hexley	0:281d6ff68967	674	/* send a RST to bring the other side in a non-synchronized state. */
hexley	0:281d6ff68967	675	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
hexley	0:281d6ff68967	676	tcphdr->dest, tcphdr->src);
hexley	0:281d6ff68967	677	}
hexley	0:281d6ff68967	678	break;
hexley	0:281d6ff68967	679	case SYN_RCVD:
hexley	0:281d6ff68967	680	if (flags & TCP_ACK) {
hexley	0:281d6ff68967	681	/* expected ACK number? */
hexley	0:281d6ff68967	682	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
hexley	0:281d6ff68967	683	u16_t old_cwnd;
hexley	0:281d6ff68967	684	pcb->state = ESTABLISHED;
hexley	0:281d6ff68967	685	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
hexley	0:281d6ff68967	686	#if LWIP_CALLBACK_API
hexley	0:281d6ff68967	687	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
hexley	0:281d6ff68967	688	#endif
hexley	0:281d6ff68967	689	/* Call the accept function. */
hexley	0:281d6ff68967	690	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
hexley	0:281d6ff68967	691	if (err != ERR_OK) {
hexley	0:281d6ff68967	692	/* If the accept function returns with an error, we abort
hexley	0:281d6ff68967	693	* the connection. */
hexley	0:281d6ff68967	694	/* Already aborted? */
hexley	0:281d6ff68967	695	if (err != ERR_ABRT) {
hexley	0:281d6ff68967	696	tcp_abort(pcb);
hexley	0:281d6ff68967	697	}
hexley	0:281d6ff68967	698	return ERR_ABRT;
hexley	0:281d6ff68967	699	}
hexley	0:281d6ff68967	700	old_cwnd = pcb->cwnd;
hexley	0:281d6ff68967	701	/* If there was any data contained within this ACK,
hexley	0:281d6ff68967	702	* we'd better pass it on to the application as well. */
hexley	0:281d6ff68967	703	tcp_receive(pcb);
hexley	0:281d6ff68967	704
hexley	0:281d6ff68967	705	/* Prevent ACK for SYN to generate a sent event */
hexley	0:281d6ff68967	706	if (pcb->acked != 0) {
hexley	0:281d6ff68967	707	pcb->acked--;
hexley	0:281d6ff68967	708	}
hexley	0:281d6ff68967	709
hexley	0:281d6ff68967	710	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
hexley	0:281d6ff68967	711
hexley	0:281d6ff68967	712	if (recv_flags & TF_GOT_FIN) {
hexley	0:281d6ff68967	713	tcp_ack_now(pcb);
hexley	0:281d6ff68967	714	pcb->state = CLOSE_WAIT;
hexley	0:281d6ff68967	715	}
hexley	0:281d6ff68967	716	} else {
hexley	0:281d6ff68967	717	/* incorrect ACK number, send RST */
hexley	0:281d6ff68967	718	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
hexley	0:281d6ff68967	719	tcphdr->dest, tcphdr->src);
hexley	0:281d6ff68967	720	}
hexley	0:281d6ff68967	721	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
hexley	0:281d6ff68967	722	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
hexley	0:281d6ff68967	723	tcp_rexmit(pcb);
hexley	0:281d6ff68967	724	}
hexley	0:281d6ff68967	725	break;
hexley	0:281d6ff68967	726	case CLOSE_WAIT:
hexley	0:281d6ff68967	727	/* FALLTHROUGH */
hexley	0:281d6ff68967	728	case ESTABLISHED:
hexley	0:281d6ff68967	729	tcp_receive(pcb);
hexley	0:281d6ff68967	730	if (recv_flags & TF_GOT_FIN) { /* passive close */
hexley	0:281d6ff68967	731	tcp_ack_now(pcb);
hexley	0:281d6ff68967	732	pcb->state = CLOSE_WAIT;
hexley	0:281d6ff68967	733	}
hexley	0:281d6ff68967	734	break;
hexley	0:281d6ff68967	735	case FIN_WAIT_1:
hexley	0:281d6ff68967	736	tcp_receive(pcb);
hexley	0:281d6ff68967	737	if (recv_flags & TF_GOT_FIN) {
hexley	0:281d6ff68967	738	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
hexley	0:281d6ff68967	739	LWIP_DEBUGF(TCP_DEBUG,
hexley	0:281d6ff68967	740	("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
hexley	0:281d6ff68967	741	tcp_ack_now(pcb);
hexley	0:281d6ff68967	742	tcp_pcb_purge(pcb);
hexley	0:281d6ff68967	743	TCP_RMV(&tcp_active_pcbs, pcb);
hexley	0:281d6ff68967	744	pcb->state = TIME_WAIT;
hexley	0:281d6ff68967	745	TCP_REG(&tcp_tw_pcbs, pcb);
hexley	0:281d6ff68967	746	} else {
hexley	0:281d6ff68967	747	tcp_ack_now(pcb);
hexley	0:281d6ff68967	748	pcb->state = CLOSING;
hexley	0:281d6ff68967	749	}
hexley	0:281d6ff68967	750	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
hexley	0:281d6ff68967	751	pcb->state = FIN_WAIT_2;
hexley	0:281d6ff68967	752	}
hexley	0:281d6ff68967	753	break;
hexley	0:281d6ff68967	754	case FIN_WAIT_2:
hexley	0:281d6ff68967	755	tcp_receive(pcb);
hexley	0:281d6ff68967	756	if (recv_flags & TF_GOT_FIN) {
hexley	0:281d6ff68967	757	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
hexley	0:281d6ff68967	758	tcp_ack_now(pcb);
hexley	0:281d6ff68967	759	tcp_pcb_purge(pcb);
hexley	0:281d6ff68967	760	TCP_RMV(&tcp_active_pcbs, pcb);
hexley	0:281d6ff68967	761	pcb->state = TIME_WAIT;
hexley	0:281d6ff68967	762	TCP_REG(&tcp_tw_pcbs, pcb);
hexley	0:281d6ff68967	763	}
hexley	0:281d6ff68967	764	break;
hexley	0:281d6ff68967	765	case CLOSING:
hexley	0:281d6ff68967	766	tcp_receive(pcb);
hexley	0:281d6ff68967	767	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
hexley	0:281d6ff68967	768	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
hexley	0:281d6ff68967	769	tcp_pcb_purge(pcb);
hexley	0:281d6ff68967	770	TCP_RMV(&tcp_active_pcbs, pcb);
hexley	0:281d6ff68967	771	pcb->state = TIME_WAIT;
hexley	0:281d6ff68967	772	TCP_REG(&tcp_tw_pcbs, pcb);
hexley	0:281d6ff68967	773	}
hexley	0:281d6ff68967	774	break;
hexley	0:281d6ff68967	775	case LAST_ACK:
hexley	0:281d6ff68967	776	tcp_receive(pcb);
hexley	0:281d6ff68967	777	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
hexley	0:281d6ff68967	778	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
hexley	0:281d6ff68967	779	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
hexley	0:281d6ff68967	780	recv_flags \|= TF_CLOSED;
hexley	0:281d6ff68967	781	}
hexley	0:281d6ff68967	782	break;
hexley	0:281d6ff68967	783	default:
hexley	0:281d6ff68967	784	break;
hexley	0:281d6ff68967	785	}
hexley	0:281d6ff68967	786	return ERR_OK;
hexley	0:281d6ff68967	787	}
hexley	0:281d6ff68967	788
hexley	0:281d6ff68967	789	#if TCP_QUEUE_OOSEQ
hexley	0:281d6ff68967	790	/**
hexley	0:281d6ff68967	791	* Insert segment into the list (segments covered with new one will be deleted)
hexley	0:281d6ff68967	792	*
hexley	0:281d6ff68967	793	* Called from tcp_receive()
hexley	0:281d6ff68967	794	*/
hexley	0:281d6ff68967	795	static void
hexley	0:281d6ff68967	796	tcp_oos_insert_segment(struct tcp_seg cseg, struct tcp_seg next)
hexley	0:281d6ff68967	797	{
hexley	0:281d6ff68967	798	struct tcp_seg *old_seg;
hexley	0:281d6ff68967	799
hexley	0:281d6ff68967	800	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	801	/* received segment overlaps all following segments */
hexley	0:281d6ff68967	802	tcp_segs_free(next);
hexley	0:281d6ff68967	803	next = NULL;
hexley	0:281d6ff68967	804	}
hexley	0:281d6ff68967	805	else {
hexley	0:281d6ff68967	806	/* delete some following segments
hexley	0:281d6ff68967	807	oos queue may have segments with FIN flag */
hexley	0:281d6ff68967	808	while (next &&
hexley	0:281d6ff68967	809	TCP_SEQ_GEQ((seqno + cseg->len),
hexley	0:281d6ff68967	810	(next->tcphdr->seqno + next->len))) {
hexley	0:281d6ff68967	811	/* cseg with FIN already processed */
hexley	0:281d6ff68967	812	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	813	TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
hexley	0:281d6ff68967	814	}
hexley	0:281d6ff68967	815	old_seg = next;
hexley	0:281d6ff68967	816	next = next->next;
hexley	0:281d6ff68967	817	tcp_seg_free(old_seg);
hexley	0:281d6ff68967	818	}
hexley	0:281d6ff68967	819	if (next &&
hexley	0:281d6ff68967	820	TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
hexley	0:281d6ff68967	821	/* We need to trim the incoming segment. */
hexley	0:281d6ff68967	822	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
hexley	0:281d6ff68967	823	pbuf_realloc(cseg->p, cseg->len);
hexley	0:281d6ff68967	824	}
hexley	0:281d6ff68967	825	}
hexley	0:281d6ff68967	826	cseg->next = next;
hexley	0:281d6ff68967	827	}
hexley	0:281d6ff68967	828	#endif /* TCP_QUEUE_OOSEQ */
hexley	0:281d6ff68967	829
hexley	0:281d6ff68967	830	/**
hexley	0:281d6ff68967	831	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
hexley	0:281d6ff68967	832	* data, and if so frees the memory of the buffered data. Next, is places the
hexley	0:281d6ff68967	833	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
hexley	0:281d6ff68967	834	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
hexley	0:281d6ff68967	835	* i it has been removed from the buffer.
hexley	0:281d6ff68967	836	*
hexley	0:281d6ff68967	837	* If the incoming segment constitutes an ACK for a segment that was used for RTT
hexley	0:281d6ff68967	838	* estimation, the RTT is estimated here as well.
hexley	0:281d6ff68967	839	*
hexley	0:281d6ff68967	840	* Called from tcp_process().
hexley	0:281d6ff68967	841	*/
hexley	0:281d6ff68967	842	static void
hexley	0:281d6ff68967	843	tcp_receive(struct tcp_pcb *pcb)
hexley	0:281d6ff68967	844	{
hexley	0:281d6ff68967	845	struct tcp_seg *next;
hexley	0:281d6ff68967	846	#if TCP_QUEUE_OOSEQ
hexley	0:281d6ff68967	847	struct tcp_seg prev, cseg;
hexley	0:281d6ff68967	848	#endif /* TCP_QUEUE_OOSEQ */
hexley	0:281d6ff68967	849	struct pbuf *p;
hexley	0:281d6ff68967	850	s32_t off;
hexley	0:281d6ff68967	851	s16_t m;
hexley	0:281d6ff68967	852	u32_t right_wnd_edge;
hexley	0:281d6ff68967	853	u16_t new_tot_len;
hexley	0:281d6ff68967	854	int found_dupack = 0;
hexley	0:281d6ff68967	855
hexley	0:281d6ff68967	856	if (flags & TCP_ACK) {
hexley	0:281d6ff68967	857	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
hexley	0:281d6ff68967	858
hexley	0:281d6ff68967	859	/* Update window. */
hexley	0:281d6ff68967	860	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
hexley	0:281d6ff68967	861	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
hexley	0:281d6ff68967	862	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
hexley	0:281d6ff68967	863	pcb->snd_wnd = tcphdr->wnd;
hexley	0:281d6ff68967	864	pcb->snd_wl1 = seqno;
hexley	0:281d6ff68967	865	pcb->snd_wl2 = ackno;
hexley	0:281d6ff68967	866	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
hexley	0:281d6ff68967	867	pcb->persist_backoff = 0;
hexley	0:281d6ff68967	868	}
hexley	0:281d6ff68967	869	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
hexley	0:281d6ff68967	870	#if TCP_WND_DEBUG
hexley	0:281d6ff68967	871	} else {
hexley	0:281d6ff68967	872	if (pcb->snd_wnd != tcphdr->wnd) {
hexley	0:281d6ff68967	873	LWIP_DEBUGF(TCP_WND_DEBUG,
hexley	0:281d6ff68967	874	("tcp_receive: no window update lastack %"U32_F" ackno %"
hexley	0:281d6ff68967	875	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
hexley	0:281d6ff68967	876	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
hexley	0:281d6ff68967	877	}
hexley	0:281d6ff68967	878	#endif /* TCP_WND_DEBUG */
hexley	0:281d6ff68967	879	}
hexley	0:281d6ff68967	880
hexley	0:281d6ff68967	881	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
hexley	0:281d6ff68967	882	* duplicate ack if:
hexley	0:281d6ff68967	883	* 1) It doesn't ACK new data
hexley	0:281d6ff68967	884	* 2) length of received packet is zero (i.e. no payload)
hexley	0:281d6ff68967	885	* 3) the advertised window hasn't changed
hexley	0:281d6ff68967	886	* 4) There is outstanding unacknowledged data (retransmission timer running)
hexley	0:281d6ff68967	887	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
hexley	0:281d6ff68967	888	*
hexley	0:281d6ff68967	889	* If it passes all five, should process as a dupack:
hexley	0:281d6ff68967	890	* a) dupacks < 3: do nothing
hexley	0:281d6ff68967	891	* b) dupacks == 3: fast retransmit
hexley	0:281d6ff68967	892	* c) dupacks > 3: increase cwnd
hexley	0:281d6ff68967	893	*
hexley	0:281d6ff68967	894	* If it only passes 1-3, should reset dupack counter (and add to
hexley	0:281d6ff68967	895	* stats, which we don't do in lwIP)
hexley	0:281d6ff68967	896	*
hexley	0:281d6ff68967	897	* If it only passes 1, should reset dupack counter
hexley	0:281d6ff68967	898	*
hexley	0:281d6ff68967	899	*/
hexley	0:281d6ff68967	900
hexley	0:281d6ff68967	901	/* Clause 1 */
hexley	0:281d6ff68967	902	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
hexley	0:281d6ff68967	903	pcb->acked = 0;
hexley	0:281d6ff68967	904	/* Clause 2 */
hexley	0:281d6ff68967	905	if (tcplen == 0) {
hexley	0:281d6ff68967	906	/* Clause 3 */
hexley	0:281d6ff68967	907	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
hexley	0:281d6ff68967	908	/* Clause 4 */
hexley	0:281d6ff68967	909	if (pcb->rtime >= 0) {
hexley	0:281d6ff68967	910	/* Clause 5 */
hexley	0:281d6ff68967	911	if (pcb->lastack == ackno) {
hexley	0:281d6ff68967	912	found_dupack = 1;
hexley	0:281d6ff68967	913	if (pcb->dupacks + 1 > pcb->dupacks)
hexley	0:281d6ff68967	914	++pcb->dupacks;
hexley	0:281d6ff68967	915	if (pcb->dupacks > 3) {
hexley	0:281d6ff68967	916	/* Inflate the congestion window, but not if it means that
hexley	0:281d6ff68967	917	the value overflows. */
hexley	0:281d6ff68967	918	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
hexley	0:281d6ff68967	919	pcb->cwnd += pcb->mss;
hexley	0:281d6ff68967	920	}
hexley	0:281d6ff68967	921	} else if (pcb->dupacks == 3) {
hexley	0:281d6ff68967	922	/* Do fast retransmit */
hexley	0:281d6ff68967	923	tcp_rexmit_fast(pcb);
hexley	0:281d6ff68967	924	}
hexley	0:281d6ff68967	925	}
hexley	0:281d6ff68967	926	}
hexley	0:281d6ff68967	927	}
hexley	0:281d6ff68967	928	}
hexley	0:281d6ff68967	929	/* If Clause (1) or more is true, but not a duplicate ack, reset
hexley	0:281d6ff68967	930	* count of consecutive duplicate acks */
hexley	0:281d6ff68967	931	if (!found_dupack) {
hexley	0:281d6ff68967	932	pcb->dupacks = 0;
hexley	0:281d6ff68967	933	}
hexley	0:281d6ff68967	934	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
hexley	0:281d6ff68967	935	/* We come here when the ACK acknowledges new data. */
hexley	0:281d6ff68967	936
hexley	0:281d6ff68967	937	/* Reset the "IN Fast Retransmit" flag, since we are no longer
hexley	0:281d6ff68967	938	in fast retransmit. Also reset the congestion window to the
hexley	0:281d6ff68967	939	slow start threshold. */
hexley	0:281d6ff68967	940	if (pcb->flags & TF_INFR) {
hexley	0:281d6ff68967	941	pcb->flags &= ~TF_INFR;
hexley	0:281d6ff68967	942	pcb->cwnd = pcb->ssthresh;
hexley	0:281d6ff68967	943	}
hexley	0:281d6ff68967	944
hexley	0:281d6ff68967	945	/* Reset the number of retransmissions. */
hexley	0:281d6ff68967	946	pcb->nrtx = 0;
hexley	0:281d6ff68967	947
hexley	0:281d6ff68967	948	/* Reset the retransmission time-out. */
hexley	0:281d6ff68967	949	pcb->rto = (pcb->sa >> 3) + pcb->sv;
hexley	0:281d6ff68967	950
hexley	0:281d6ff68967	951	/* Update the send buffer space. Diff between the two can never exceed 64K? */
hexley	0:281d6ff68967	952	pcb->acked = (u16_t)(ackno - pcb->lastack);
hexley	0:281d6ff68967	953
hexley	0:281d6ff68967	954	pcb->snd_buf += pcb->acked;
hexley	0:281d6ff68967	955
hexley	0:281d6ff68967	956	/* Reset the fast retransmit variables. */
hexley	0:281d6ff68967	957	pcb->dupacks = 0;
hexley	0:281d6ff68967	958	pcb->lastack = ackno;
hexley	0:281d6ff68967	959
hexley	0:281d6ff68967	960	/* Update the congestion control variables (cwnd and
hexley	0:281d6ff68967	961	ssthresh). */
hexley	0:281d6ff68967	962	if (pcb->state >= ESTABLISHED) {
hexley	0:281d6ff68967	963	if (pcb->cwnd < pcb->ssthresh) {
hexley	0:281d6ff68967	964	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
hexley	0:281d6ff68967	965	pcb->cwnd += pcb->mss;
hexley	0:281d6ff68967	966	}
hexley	0:281d6ff68967	967	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
hexley	0:281d6ff68967	968	} else {
hexley	0:281d6ff68967	969	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
hexley	0:281d6ff68967	970	if (new_cwnd > pcb->cwnd) {
hexley	0:281d6ff68967	971	pcb->cwnd = new_cwnd;
hexley	0:281d6ff68967	972	}
hexley	0:281d6ff68967	973	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
hexley	0:281d6ff68967	974	}
hexley	0:281d6ff68967	975	}
hexley	0:281d6ff68967	976	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
hexley	0:281d6ff68967	977	ackno,
hexley	0:281d6ff68967	978	pcb->unacked != NULL?
hexley	0:281d6ff68967	979	ntohl(pcb->unacked->tcphdr->seqno): 0,
hexley	0:281d6ff68967	980	pcb->unacked != NULL?
hexley	0:281d6ff68967	981	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
hexley	0:281d6ff68967	982
hexley	0:281d6ff68967	983	/* Remove segment from the unacknowledged list if the incoming
hexley	0:281d6ff68967	984	ACK acknowlegdes them. */
hexley	0:281d6ff68967	985	while (pcb->unacked != NULL &&
hexley	0:281d6ff68967	986	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
hexley	0:281d6ff68967	987	TCP_TCPLEN(pcb->unacked), ackno)) {
hexley	0:281d6ff68967	988	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
hexley	0:281d6ff68967	989	ntohl(pcb->unacked->tcphdr->seqno),
hexley	0:281d6ff68967	990	ntohl(pcb->unacked->tcphdr->seqno) +
hexley	0:281d6ff68967	991	TCP_TCPLEN(pcb->unacked)));
hexley	0:281d6ff68967	992
hexley	0:281d6ff68967	993	next = pcb->unacked;
hexley	0:281d6ff68967	994	pcb->unacked = pcb->unacked->next;
hexley	0:281d6ff68967	995
hexley	0:281d6ff68967	996	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
hexley	0:281d6ff68967	997	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
hexley	0:281d6ff68967	998	/* Prevent ACK for FIN to generate a sent event */
hexley	0:281d6ff68967	999	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
hexley	0:281d6ff68967	1000	pcb->acked--;
hexley	0:281d6ff68967	1001	}
hexley	0:281d6ff68967	1002
hexley	0:281d6ff68967	1003	pcb->snd_queuelen -= pbuf_clen(next->p);
hexley	0:281d6ff68967	1004	tcp_seg_free(next);
hexley	0:281d6ff68967	1005
hexley	0:281d6ff68967	1006	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
hexley	0:281d6ff68967	1007	if (pcb->snd_queuelen != 0) {
hexley	0:281d6ff68967	1008	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
hexley	0:281d6ff68967	1009	pcb->unsent != NULL);
hexley	0:281d6ff68967	1010	}
hexley	0:281d6ff68967	1011	}
hexley	0:281d6ff68967	1012
hexley	0:281d6ff68967	1013	/* If there's nothing left to acknowledge, stop the retransmit
hexley	0:281d6ff68967	1014	timer, otherwise reset it to start again */
hexley	0:281d6ff68967	1015	if(pcb->unacked == NULL)
hexley	0:281d6ff68967	1016	pcb->rtime = -1;
hexley	0:281d6ff68967	1017	else
hexley	0:281d6ff68967	1018	pcb->rtime = 0;
hexley	0:281d6ff68967	1019
hexley	0:281d6ff68967	1020	pcb->polltmr = 0;
hexley	0:281d6ff68967	1021	} else {
hexley	0:281d6ff68967	1022	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
hexley	0:281d6ff68967	1023	pcb->acked = 0;
hexley	0:281d6ff68967	1024	}
hexley	0:281d6ff68967	1025
hexley	0:281d6ff68967	1026	/* We go through the ->unsent list to see if any of the segments
hexley	0:281d6ff68967	1027	on the list are acknowledged by the ACK. This may seem
hexley	0:281d6ff68967	1028	strange since an "unsent" segment shouldn't be acked. The
hexley	0:281d6ff68967	1029	rationale is that lwIP puts all outstanding segments on the
hexley	0:281d6ff68967	1030	->unsent list after a retransmission, so these segments may
hexley	0:281d6ff68967	1031	in fact have been sent once. */
hexley	0:281d6ff68967	1032	while (pcb->unsent != NULL &&
hexley	0:281d6ff68967	1033	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
hexley	0:281d6ff68967	1034	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
hexley	0:281d6ff68967	1035	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
hexley	0:281d6ff68967	1036	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
hexley	0:281d6ff68967	1037	TCP_TCPLEN(pcb->unsent)));
hexley	0:281d6ff68967	1038
hexley	0:281d6ff68967	1039	next = pcb->unsent;
hexley	0:281d6ff68967	1040	pcb->unsent = pcb->unsent->next;
hexley	0:281d6ff68967	1041	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
hexley	0:281d6ff68967	1042	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
hexley	0:281d6ff68967	1043	/* Prevent ACK for FIN to generate a sent event */
hexley	0:281d6ff68967	1044	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
hexley	0:281d6ff68967	1045	pcb->acked--;
hexley	0:281d6ff68967	1046	}
hexley	0:281d6ff68967	1047	pcb->snd_queuelen -= pbuf_clen(next->p);
hexley	0:281d6ff68967	1048	tcp_seg_free(next);
hexley	0:281d6ff68967	1049	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
hexley	0:281d6ff68967	1050	if (pcb->snd_queuelen != 0) {
hexley	0:281d6ff68967	1051	LWIP_ASSERT("tcp_receive: valid queue length",
hexley	0:281d6ff68967	1052	pcb->unacked != NULL \|\| pcb->unsent != NULL);
hexley	0:281d6ff68967	1053	}
hexley	0:281d6ff68967	1054	}
hexley	0:281d6ff68967	1055	/* End of ACK for new data processing. */
hexley	0:281d6ff68967	1056
hexley	0:281d6ff68967	1057	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
hexley	0:281d6ff68967	1058	pcb->rttest, pcb->rtseq, ackno));
hexley	0:281d6ff68967	1059
hexley	0:281d6ff68967	1060	/* RTT estimation calculations. This is done by checking if the
hexley	0:281d6ff68967	1061	incoming segment acknowledges the segment we use to take a
hexley	0:281d6ff68967	1062	round-trip time measurement. */
hexley	0:281d6ff68967	1063	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
hexley	0:281d6ff68967	1064	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
hexley	0:281d6ff68967	1065	and a round-trip shouldn't be that long... */
hexley	0:281d6ff68967	1066	m = (s16_t)(tcp_ticks - pcb->rttest);
hexley	0:281d6ff68967	1067
hexley	0:281d6ff68967	1068	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
hexley	0:281d6ff68967	1069	m, m * TCP_SLOW_INTERVAL));
hexley	0:281d6ff68967	1070
hexley	0:281d6ff68967	1071	/* This is taken directly from VJs original code in his paper */
hexley	0:281d6ff68967	1072	m = m - (pcb->sa >> 3);
hexley	0:281d6ff68967	1073	pcb->sa += m;
hexley	0:281d6ff68967	1074	if (m < 0) {
hexley	0:281d6ff68967	1075	m = -m;
hexley	0:281d6ff68967	1076	}
hexley	0:281d6ff68967	1077	m = m - (pcb->sv >> 2);
hexley	0:281d6ff68967	1078	pcb->sv += m;
hexley	0:281d6ff68967	1079	pcb->rto = (pcb->sa >> 3) + pcb->sv;
hexley	0:281d6ff68967	1080
hexley	0:281d6ff68967	1081	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
hexley	0:281d6ff68967	1082	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
hexley	0:281d6ff68967	1083
hexley	0:281d6ff68967	1084	pcb->rttest = 0;
hexley	0:281d6ff68967	1085	}
hexley	0:281d6ff68967	1086	}
hexley	0:281d6ff68967	1087
hexley	0:281d6ff68967	1088	/* If the incoming segment contains data, we must process it
hexley	0:281d6ff68967	1089	further. */
hexley	0:281d6ff68967	1090	if (tcplen > 0) {
hexley	0:281d6ff68967	1091	/* This code basically does three things:
hexley	0:281d6ff68967	1092
hexley	0:281d6ff68967	1093	+) If the incoming segment contains data that is the next
hexley	0:281d6ff68967	1094	in-sequence data, this data is passed to the application. This
hexley	0:281d6ff68967	1095	might involve trimming the first edge of the data. The rcv_nxt
hexley	0:281d6ff68967	1096	variable and the advertised window are adjusted.
hexley	0:281d6ff68967	1097
hexley	0:281d6ff68967	1098	+) If the incoming segment has data that is above the next
hexley	0:281d6ff68967	1099	sequence number expected (->rcv_nxt), the segment is placed on
hexley	0:281d6ff68967	1100	the ->ooseq queue. This is done by finding the appropriate
hexley	0:281d6ff68967	1101	place in the ->ooseq queue (which is ordered by sequence
hexley	0:281d6ff68967	1102	number) and trim the segment in both ends if needed. An
hexley	0:281d6ff68967	1103	immediate ACK is sent to indicate that we received an
hexley	0:281d6ff68967	1104	out-of-sequence segment.
hexley	0:281d6ff68967	1105
hexley	0:281d6ff68967	1106	+) Finally, we check if the first segment on the ->ooseq queue
hexley	0:281d6ff68967	1107	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
hexley	0:281d6ff68967	1108	rcv_nxt > ooseq->seqno, we must trim the first edge of the
hexley	0:281d6ff68967	1109	segment on ->ooseq before we adjust rcv_nxt. The data in the
hexley	0:281d6ff68967	1110	segments that are now on sequence are chained onto the
hexley	0:281d6ff68967	1111	incoming segment so that we only need to call the application
hexley	0:281d6ff68967	1112	once.
hexley	0:281d6ff68967	1113	*/
hexley	0:281d6ff68967	1114
hexley	0:281d6ff68967	1115	/* First, we check if we must trim the first edge. We have to do
hexley	0:281d6ff68967	1116	this if the sequence number of the incoming segment is less
hexley	0:281d6ff68967	1117	than rcv_nxt, and the sequence number plus the length of the
hexley	0:281d6ff68967	1118	segment is larger than rcv_nxt. */
hexley	0:281d6ff68967	1119	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
hexley	0:281d6ff68967	1120	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
hexley	0:281d6ff68967	1121	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
hexley	0:281d6ff68967	1122	/* Trimming the first edge is done by pushing the payload
hexley	0:281d6ff68967	1123	pointer in the pbuf downwards. This is somewhat tricky since
hexley	0:281d6ff68967	1124	we do not want to discard the full contents of the pbuf up to
hexley	0:281d6ff68967	1125	the new starting point of the data since we have to keep the
hexley	0:281d6ff68967	1126	TCP header which is present in the first pbuf in the chain.
hexley	0:281d6ff68967	1127
hexley	0:281d6ff68967	1128	What is done is really quite a nasty hack: the first pbuf in
hexley	0:281d6ff68967	1129	the pbuf chain is pointed to by inseg.p. Since we need to be
hexley	0:281d6ff68967	1130	able to deallocate the whole pbuf, we cannot change this
hexley	0:281d6ff68967	1131	inseg.p pointer to point to any of the later pbufs in the
hexley	0:281d6ff68967	1132	chain. Instead, we point the ->payload pointer in the first
hexley	0:281d6ff68967	1133	pbuf to data in one of the later pbufs. We also set the
hexley	0:281d6ff68967	1134	inseg.data pointer to point to the right place. This way, the
hexley	0:281d6ff68967	1135	->p pointer will still point to the first pbuf, but the
hexley	0:281d6ff68967	1136	->p->payload pointer will point to data in another pbuf.
hexley	0:281d6ff68967	1137
hexley	0:281d6ff68967	1138	After we are done with adjusting the pbuf pointers we must
hexley	0:281d6ff68967	1139	adjust the ->data pointer in the seg and the segment
hexley	0:281d6ff68967	1140	length.*/
hexley	0:281d6ff68967	1141
hexley	0:281d6ff68967	1142	off = pcb->rcv_nxt - seqno;
hexley	0:281d6ff68967	1143	p = inseg.p;
hexley	0:281d6ff68967	1144	LWIP_ASSERT("inseg.p != NULL", inseg.p);
hexley	0:281d6ff68967	1145	LWIP_ASSERT("insane offset!", (off < 0x7fff));
hexley	0:281d6ff68967	1146	if (inseg.p->len < off) {
hexley	0:281d6ff68967	1147	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
hexley	0:281d6ff68967	1148	new_tot_len = (u16_t)(inseg.p->tot_len - off);
hexley	0:281d6ff68967	1149	while (p->len < off) {
hexley	0:281d6ff68967	1150	off -= p->len;
hexley	0:281d6ff68967	1151	/* KJM following line changed (with addition of new_tot_len var)
hexley	0:281d6ff68967	1152	to fix bug #9076
hexley	0:281d6ff68967	1153	inseg.p->tot_len -= p->len; */
hexley	0:281d6ff68967	1154	p->tot_len = new_tot_len;
hexley	0:281d6ff68967	1155	p->len = 0;
hexley	0:281d6ff68967	1156	p = p->next;
hexley	0:281d6ff68967	1157	}
hexley	0:281d6ff68967	1158	if(pbuf_header(p, (s16_t)-off)) {
hexley	0:281d6ff68967	1159	/* Do we need to cope with this failing? Assert for now */
hexley	0:281d6ff68967	1160	LWIP_ASSERT("pbuf_header failed", 0);
hexley	0:281d6ff68967	1161	}
hexley	0:281d6ff68967	1162	} else {
hexley	0:281d6ff68967	1163	if(pbuf_header(inseg.p, (s16_t)-off)) {
hexley	0:281d6ff68967	1164	/* Do we need to cope with this failing? Assert for now */
hexley	0:281d6ff68967	1165	LWIP_ASSERT("pbuf_header failed", 0);
hexley	0:281d6ff68967	1166	}
hexley	0:281d6ff68967	1167	}
hexley	0:281d6ff68967	1168	/* KJM following line changed to use p->payload rather than inseg->p->payload
hexley	0:281d6ff68967	1169	to fix bug #9076 */
hexley	0:281d6ff68967	1170	inseg.dataptr = p->payload;
hexley	0:281d6ff68967	1171	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
hexley	0:281d6ff68967	1172	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
hexley	0:281d6ff68967	1173	}
hexley	0:281d6ff68967	1174	else {
hexley	0:281d6ff68967	1175	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
hexley	0:281d6ff68967	1176	/* the whole segment is < rcv_nxt */
hexley	0:281d6ff68967	1177	/* must be a duplicate of a packet that has already been correctly handled */
hexley	0:281d6ff68967	1178
hexley	0:281d6ff68967	1179	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
hexley	0:281d6ff68967	1180	tcp_ack_now(pcb);
hexley	0:281d6ff68967	1181	}
hexley	0:281d6ff68967	1182	}
hexley	0:281d6ff68967	1183
hexley	0:281d6ff68967	1184	/* The sequence number must be within the window (above rcv_nxt
hexley	0:281d6ff68967	1185	and below rcv_nxt + rcv_wnd) in order to be further
hexley	0:281d6ff68967	1186	processed. */
hexley	0:281d6ff68967	1187	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
hexley	0:281d6ff68967	1188	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
hexley	0:281d6ff68967	1189	if (pcb->rcv_nxt == seqno) {
hexley	0:281d6ff68967	1190	/* The incoming segment is the next in sequence. We check if
hexley	0:281d6ff68967	1191	we have to trim the end of the segment and update rcv_nxt
hexley	0:281d6ff68967	1192	and pass the data to the application. */
hexley	0:281d6ff68967	1193	tcplen = TCP_TCPLEN(&inseg);
hexley	0:281d6ff68967	1194
hexley	0:281d6ff68967	1195	if (tcplen > pcb->rcv_wnd) {
hexley	0:281d6ff68967	1196	LWIP_DEBUGF(TCP_INPUT_DEBUG,
hexley	0:281d6ff68967	1197	("tcp_receive: other end overran receive window"
hexley	0:281d6ff68967	1198	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
hexley	0:281d6ff68967	1199	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
hexley	0:281d6ff68967	1200	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1201	/* Must remove the FIN from the header as we're trimming
hexley	0:281d6ff68967	1202	* that byte of sequence-space from the packet */
hexley	0:281d6ff68967	1203	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
hexley	0:281d6ff68967	1204	}
hexley	0:281d6ff68967	1205	/* Adjust length of segment to fit in the window. */
hexley	0:281d6ff68967	1206	inseg.len = pcb->rcv_wnd;
hexley	0:281d6ff68967	1207	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
hexley	0:281d6ff68967	1208	inseg.len -= 1;
hexley	0:281d6ff68967	1209	}
hexley	0:281d6ff68967	1210	pbuf_realloc(inseg.p, inseg.len);
hexley	0:281d6ff68967	1211	tcplen = TCP_TCPLEN(&inseg);
hexley	0:281d6ff68967	1212	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
hexley	0:281d6ff68967	1213	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
hexley	0:281d6ff68967	1214	}
hexley	0:281d6ff68967	1215	#if TCP_QUEUE_OOSEQ
hexley	0:281d6ff68967	1216	/* Received in-sequence data, adjust ooseq data if:
hexley	0:281d6ff68967	1217	- FIN has been received or
hexley	0:281d6ff68967	1218	- inseq overlaps with ooseq */
hexley	0:281d6ff68967	1219	if (pcb->ooseq != NULL) {
hexley	0:281d6ff68967	1220	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1221	LWIP_DEBUGF(TCP_INPUT_DEBUG,
hexley	0:281d6ff68967	1222	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
hexley	0:281d6ff68967	1223	/* Received in-order FIN means anything that was received
hexley	0:281d6ff68967	1224	* out of order must now have been received in-order, so
hexley	0:281d6ff68967	1225	* bin the ooseq queue */
hexley	0:281d6ff68967	1226	while (pcb->ooseq != NULL) {
hexley	0:281d6ff68967	1227	struct tcp_seg *old_ooseq = pcb->ooseq;
hexley	0:281d6ff68967	1228	pcb->ooseq = pcb->ooseq->next;
hexley	0:281d6ff68967	1229	tcp_seg_free(old_ooseq);
hexley	0:281d6ff68967	1230	}
hexley	0:281d6ff68967	1231	}
hexley	0:281d6ff68967	1232	else {
hexley	0:281d6ff68967	1233	next = pcb->ooseq;
hexley	0:281d6ff68967	1234	/* Remove all segments on ooseq that are covered by inseg already.
hexley	0:281d6ff68967	1235	* FIN is copied from ooseq to inseg if present. */
hexley	0:281d6ff68967	1236	while (next &&
hexley	0:281d6ff68967	1237	TCP_SEQ_GEQ(seqno + tcplen,
hexley	0:281d6ff68967	1238	next->tcphdr->seqno + next->len)) {
hexley	0:281d6ff68967	1239	/* inseg cannot have FIN here (already processed above) */
hexley	0:281d6ff68967	1240	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
hexley	0:281d6ff68967	1241	(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
hexley	0:281d6ff68967	1242	TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
hexley	0:281d6ff68967	1243	tcplen = TCP_TCPLEN(&inseg);
hexley	0:281d6ff68967	1244	}
hexley	0:281d6ff68967	1245	prev = next;
hexley	0:281d6ff68967	1246	next = next->next;
hexley	0:281d6ff68967	1247	tcp_seg_free(prev);
hexley	0:281d6ff68967	1248	}
hexley	0:281d6ff68967	1249	/* Now trim right side of inseg if it overlaps with the first
hexley	0:281d6ff68967	1250	* segment on ooseq */
hexley	0:281d6ff68967	1251	if (next &&
hexley	0:281d6ff68967	1252	TCP_SEQ_GT(seqno + tcplen,
hexley	0:281d6ff68967	1253	next->tcphdr->seqno)) {
hexley	0:281d6ff68967	1254	/* inseg cannot have FIN here (already processed above) */
hexley	0:281d6ff68967	1255	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
hexley	0:281d6ff68967	1256	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
hexley	0:281d6ff68967	1257	inseg.len -= 1;
hexley	0:281d6ff68967	1258	}
hexley	0:281d6ff68967	1259	pbuf_realloc(inseg.p, inseg.len);
hexley	0:281d6ff68967	1260	tcplen = TCP_TCPLEN(&inseg);
hexley	0:281d6ff68967	1261	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
hexley	0:281d6ff68967	1262	(seqno + tcplen) == next->tcphdr->seqno);
hexley	0:281d6ff68967	1263	}
hexley	0:281d6ff68967	1264	pcb->ooseq = next;
hexley	0:281d6ff68967	1265	}
hexley	0:281d6ff68967	1266	}
hexley	0:281d6ff68967	1267	#endif /* TCP_QUEUE_OOSEQ */
hexley	0:281d6ff68967	1268
hexley	0:281d6ff68967	1269	pcb->rcv_nxt = seqno + tcplen;
hexley	0:281d6ff68967	1270
hexley	0:281d6ff68967	1271	/* Update the receiver's (our) window. */
hexley	0:281d6ff68967	1272	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
hexley	0:281d6ff68967	1273	pcb->rcv_wnd -= tcplen;
hexley	0:281d6ff68967	1274
hexley	0:281d6ff68967	1275	tcp_update_rcv_ann_wnd(pcb);
hexley	0:281d6ff68967	1276
hexley	0:281d6ff68967	1277	/* If there is data in the segment, we make preparations to
hexley	0:281d6ff68967	1278	pass this up to the application. The ->recv_data variable
hexley	0:281d6ff68967	1279	is used for holding the pbuf that goes to the
hexley	0:281d6ff68967	1280	application. The code for reassembling out-of-sequence data
hexley	0:281d6ff68967	1281	chains its data on this pbuf as well.
hexley	0:281d6ff68967	1282
hexley	0:281d6ff68967	1283	If the segment was a FIN, we set the TF_GOT_FIN flag that will
hexley	0:281d6ff68967	1284	be used to indicate to the application that the remote side has
hexley	0:281d6ff68967	1285	closed its end of the connection. */
hexley	0:281d6ff68967	1286	if (inseg.p->tot_len > 0) {
hexley	0:281d6ff68967	1287	recv_data = inseg.p;
hexley	0:281d6ff68967	1288	/* Since this pbuf now is the responsibility of the
hexley	0:281d6ff68967	1289	application, we delete our reference to it so that we won't
hexley	0:281d6ff68967	1290	(mistakingly) deallocate it. */
hexley	0:281d6ff68967	1291	inseg.p = NULL;
hexley	0:281d6ff68967	1292	}
hexley	0:281d6ff68967	1293	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1294	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
hexley	0:281d6ff68967	1295	recv_flags \|= TF_GOT_FIN;
hexley	0:281d6ff68967	1296	}
hexley	0:281d6ff68967	1297
hexley	0:281d6ff68967	1298	#if TCP_QUEUE_OOSEQ
hexley	0:281d6ff68967	1299	/* We now check if we have segments on the ->ooseq queue that
hexley	0:281d6ff68967	1300	are now in sequence. */
hexley	0:281d6ff68967	1301	while (pcb->ooseq != NULL &&
hexley	0:281d6ff68967	1302	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
hexley	0:281d6ff68967	1303
hexley	0:281d6ff68967	1304	cseg = pcb->ooseq;
hexley	0:281d6ff68967	1305	seqno = pcb->ooseq->tcphdr->seqno;
hexley	0:281d6ff68967	1306
hexley	0:281d6ff68967	1307	pcb->rcv_nxt += TCP_TCPLEN(cseg);
hexley	0:281d6ff68967	1308	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
hexley	0:281d6ff68967	1309	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
hexley	0:281d6ff68967	1310	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
hexley	0:281d6ff68967	1311
hexley	0:281d6ff68967	1312	tcp_update_rcv_ann_wnd(pcb);
hexley	0:281d6ff68967	1313
hexley	0:281d6ff68967	1314	if (cseg->p->tot_len > 0) {
hexley	0:281d6ff68967	1315	/* Chain this pbuf onto the pbuf that we will pass to
hexley	0:281d6ff68967	1316	the application. */
hexley	0:281d6ff68967	1317	if (recv_data) {
hexley	0:281d6ff68967	1318	pbuf_cat(recv_data, cseg->p);
hexley	0:281d6ff68967	1319	} else {
hexley	0:281d6ff68967	1320	recv_data = cseg->p;
hexley	0:281d6ff68967	1321	}
hexley	0:281d6ff68967	1322	cseg->p = NULL;
hexley	0:281d6ff68967	1323	}
hexley	0:281d6ff68967	1324	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1325	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
hexley	0:281d6ff68967	1326	recv_flags \|= TF_GOT_FIN;
hexley	0:281d6ff68967	1327	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
hexley	0:281d6ff68967	1328	pcb->state = CLOSE_WAIT;
hexley	0:281d6ff68967	1329	}
hexley	0:281d6ff68967	1330	}
hexley	0:281d6ff68967	1331
hexley	0:281d6ff68967	1332	pcb->ooseq = cseg->next;
hexley	0:281d6ff68967	1333	tcp_seg_free(cseg);
hexley	0:281d6ff68967	1334	}
hexley	0:281d6ff68967	1335	#endif /* TCP_QUEUE_OOSEQ */
hexley	0:281d6ff68967	1336
hexley	0:281d6ff68967	1337
hexley	0:281d6ff68967	1338	/* Acknowledge the segment(s). */
hexley	0:281d6ff68967	1339	tcp_ack(pcb);
hexley	0:281d6ff68967	1340
hexley	0:281d6ff68967	1341	} else {
hexley	0:281d6ff68967	1342	/* We get here if the incoming segment is out-of-sequence. */
hexley	0:281d6ff68967	1343	tcp_send_empty_ack(pcb);
hexley	0:281d6ff68967	1344	#if TCP_QUEUE_OOSEQ
hexley	0:281d6ff68967	1345	/* We queue the segment on the ->ooseq queue. */
hexley	0:281d6ff68967	1346	if (pcb->ooseq == NULL) {
hexley	0:281d6ff68967	1347	pcb->ooseq = tcp_seg_copy(&inseg);
hexley	0:281d6ff68967	1348	} else {
hexley	0:281d6ff68967	1349	/* If the queue is not empty, we walk through the queue and
hexley	0:281d6ff68967	1350	try to find a place where the sequence number of the
hexley	0:281d6ff68967	1351	incoming segment is between the sequence numbers of the
hexley	0:281d6ff68967	1352	previous and the next segment on the ->ooseq queue. That is
hexley	0:281d6ff68967	1353	the place where we put the incoming segment. If needed, we
hexley	0:281d6ff68967	1354	trim the second edges of the previous and the incoming
hexley	0:281d6ff68967	1355	segment so that it will fit into the sequence.
hexley	0:281d6ff68967	1356
hexley	0:281d6ff68967	1357	If the incoming segment has the same sequence number as a
hexley	0:281d6ff68967	1358	segment on the ->ooseq queue, we discard the segment that
hexley	0:281d6ff68967	1359	contains less data. */
hexley	0:281d6ff68967	1360
hexley	0:281d6ff68967	1361	prev = NULL;
hexley	0:281d6ff68967	1362	for(next = pcb->ooseq; next != NULL; next = next->next) {
hexley	0:281d6ff68967	1363	if (seqno == next->tcphdr->seqno) {
hexley	0:281d6ff68967	1364	/* The sequence number of the incoming segment is the
hexley	0:281d6ff68967	1365	same as the sequence number of the segment on
hexley	0:281d6ff68967	1366	->ooseq. We check the lengths to see which one to
hexley	0:281d6ff68967	1367	discard. */
hexley	0:281d6ff68967	1368	if (inseg.len > next->len) {
hexley	0:281d6ff68967	1369	/* The incoming segment is larger than the old
hexley	0:281d6ff68967	1370	segment. We replace some segments with the new
hexley	0:281d6ff68967	1371	one. */
hexley	0:281d6ff68967	1372	cseg = tcp_seg_copy(&inseg);
hexley	0:281d6ff68967	1373	if (cseg != NULL) {
hexley	0:281d6ff68967	1374	if (prev != NULL) {
hexley	0:281d6ff68967	1375	prev->next = cseg;
hexley	0:281d6ff68967	1376	} else {
hexley	0:281d6ff68967	1377	pcb->ooseq = cseg;
hexley	0:281d6ff68967	1378	}
hexley	0:281d6ff68967	1379	tcp_oos_insert_segment(cseg, next);
hexley	0:281d6ff68967	1380	}
hexley	0:281d6ff68967	1381	break;
hexley	0:281d6ff68967	1382	} else {
hexley	0:281d6ff68967	1383	/* Either the lenghts are the same or the incoming
hexley	0:281d6ff68967	1384	segment was smaller than the old one; in either
hexley	0:281d6ff68967	1385	case, we ditch the incoming segment. */
hexley	0:281d6ff68967	1386	break;
hexley	0:281d6ff68967	1387	}
hexley	0:281d6ff68967	1388	} else {
hexley	0:281d6ff68967	1389	if (prev == NULL) {
hexley	0:281d6ff68967	1390	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
hexley	0:281d6ff68967	1391	/* The sequence number of the incoming segment is lower
hexley	0:281d6ff68967	1392	than the sequence number of the first segment on the
hexley	0:281d6ff68967	1393	queue. We put the incoming segment first on the
hexley	0:281d6ff68967	1394	queue. */
hexley	0:281d6ff68967	1395	cseg = tcp_seg_copy(&inseg);
hexley	0:281d6ff68967	1396	if (cseg != NULL) {
hexley	0:281d6ff68967	1397	pcb->ooseq = cseg;
hexley	0:281d6ff68967	1398	tcp_oos_insert_segment(cseg, next);
hexley	0:281d6ff68967	1399	}
hexley	0:281d6ff68967	1400	break;
hexley	0:281d6ff68967	1401	}
hexley	0:281d6ff68967	1402	} else {
hexley	0:281d6ff68967	1403	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
hexley	0:281d6ff68967	1404	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
hexley	0:281d6ff68967	1405	if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
hexley	0:281d6ff68967	1406	/* The sequence number of the incoming segment is in
hexley	0:281d6ff68967	1407	between the sequence numbers of the previous and
hexley	0:281d6ff68967	1408	the next segment on ->ooseq. We trim trim the previous
hexley	0:281d6ff68967	1409	segment, delete next segments that included in received segment
hexley	0:281d6ff68967	1410	and trim received, if needed. */
hexley	0:281d6ff68967	1411	cseg = tcp_seg_copy(&inseg);
hexley	0:281d6ff68967	1412	if (cseg != NULL) {
hexley	0:281d6ff68967	1413	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
hexley	0:281d6ff68967	1414	/* We need to trim the prev segment. */
hexley	0:281d6ff68967	1415	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
hexley	0:281d6ff68967	1416	pbuf_realloc(prev->p, prev->len);
hexley	0:281d6ff68967	1417	}
hexley	0:281d6ff68967	1418	prev->next = cseg;
hexley	0:281d6ff68967	1419	tcp_oos_insert_segment(cseg, next);
hexley	0:281d6ff68967	1420	}
hexley	0:281d6ff68967	1421	break;
hexley	0:281d6ff68967	1422	}
hexley	0:281d6ff68967	1423	}
hexley	0:281d6ff68967	1424	/* If the "next" segment is the last segment on the
hexley	0:281d6ff68967	1425	ooseq queue, we add the incoming segment to the end
hexley	0:281d6ff68967	1426	of the list. */
hexley	0:281d6ff68967	1427	if (next->next == NULL &&
hexley	0:281d6ff68967	1428	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
hexley	0:281d6ff68967	1429	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1430	/* segment "next" already contains all data */
hexley	0:281d6ff68967	1431	break;
hexley	0:281d6ff68967	1432	}
hexley	0:281d6ff68967	1433	next->next = tcp_seg_copy(&inseg);
hexley	0:281d6ff68967	1434	if (next->next != NULL) {
hexley	0:281d6ff68967	1435	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
hexley	0:281d6ff68967	1436	/* We need to trim the last segment. */
hexley	0:281d6ff68967	1437	next->len = (u16_t)(seqno - next->tcphdr->seqno);
hexley	0:281d6ff68967	1438	pbuf_realloc(next->p, next->len);
hexley	0:281d6ff68967	1439	}
hexley	0:281d6ff68967	1440	/* check if the remote side overruns our receive window */
hexley	0:281d6ff68967	1441	if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
hexley	0:281d6ff68967	1442	LWIP_DEBUGF(TCP_INPUT_DEBUG,
hexley	0:281d6ff68967	1443	("tcp_receive: other end overran receive window"
hexley	0:281d6ff68967	1444	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
hexley	0:281d6ff68967	1445	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
hexley	0:281d6ff68967	1446	if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
hexley	0:281d6ff68967	1447	/* Must remove the FIN from the header as we're trimming
hexley	0:281d6ff68967	1448	* that byte of sequence-space from the packet */
hexley	0:281d6ff68967	1449	TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
hexley	0:281d6ff68967	1450	}
hexley	0:281d6ff68967	1451	/* Adjust length of segment to fit in the window. */
hexley	0:281d6ff68967	1452	next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
hexley	0:281d6ff68967	1453	pbuf_realloc(next->next->p, next->next->len);
hexley	0:281d6ff68967	1454	tcplen = TCP_TCPLEN(next->next);
hexley	0:281d6ff68967	1455	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
hexley	0:281d6ff68967	1456	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
hexley	0:281d6ff68967	1457	}
hexley	0:281d6ff68967	1458	}
hexley	0:281d6ff68967	1459	break;
hexley	0:281d6ff68967	1460	}
hexley	0:281d6ff68967	1461	}
hexley	0:281d6ff68967	1462	prev = next;
hexley	0:281d6ff68967	1463	}
hexley	0:281d6ff68967	1464	}
hexley	0:281d6ff68967	1465	#endif /* TCP_QUEUE_OOSEQ */
hexley	0:281d6ff68967	1466
hexley	0:281d6ff68967	1467	}
hexley	0:281d6ff68967	1468	} else {
hexley	0:281d6ff68967	1469	/* The incoming segment is not withing the window. */
hexley	0:281d6ff68967	1470	tcp_send_empty_ack(pcb);
hexley	0:281d6ff68967	1471	}
hexley	0:281d6ff68967	1472	} else {
hexley	0:281d6ff68967	1473	/* Segments with length 0 is taken care of here. Segments that
hexley	0:281d6ff68967	1474	fall out of the window are ACKed. */
hexley	0:281d6ff68967	1475	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
hexley	0:281d6ff68967	1476	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
hexley	0:281d6ff68967	1477	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
hexley	0:281d6ff68967	1478	tcp_ack_now(pcb);
hexley	0:281d6ff68967	1479	}
hexley	0:281d6ff68967	1480	}
hexley	0:281d6ff68967	1481	}
hexley	0:281d6ff68967	1482
hexley	0:281d6ff68967	1483	/**
hexley	0:281d6ff68967	1484	* Parses the options contained in the incoming segment.
hexley	0:281d6ff68967	1485	*
hexley	0:281d6ff68967	1486	* Called from tcp_listen_input() and tcp_process().
hexley	0:281d6ff68967	1487	* Currently, only the MSS option is supported!
hexley	0:281d6ff68967	1488	*
hexley	0:281d6ff68967	1489	* @param pcb the tcp_pcb for which a segment arrived
hexley	0:281d6ff68967	1490	*/
hexley	0:281d6ff68967	1491	static void
hexley	0:281d6ff68967	1492	tcp_parseopt(struct tcp_pcb *pcb)
hexley	0:281d6ff68967	1493	{
hexley	0:281d6ff68967	1494	u16_t c, max_c;
hexley	0:281d6ff68967	1495	u16_t mss;
hexley	0:281d6ff68967	1496	u8_t *opts, opt;
hexley	0:281d6ff68967	1497	#if LWIP_TCP_TIMESTAMPS
hexley	0:281d6ff68967	1498	u32_t tsval;
hexley	0:281d6ff68967	1499	#endif
hexley	0:281d6ff68967	1500
hexley	0:281d6ff68967	1501	opts = (u8_t *)tcphdr + TCP_HLEN;
hexley	0:281d6ff68967	1502
hexley	0:281d6ff68967	1503	/* Parse the TCP MSS option, if present. */
hexley	0:281d6ff68967	1504	if(TCPH_HDRLEN(tcphdr) > 0x5) {
hexley	0:281d6ff68967	1505	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
hexley	0:281d6ff68967	1506	for (c = 0; c < max_c; ) {
hexley	0:281d6ff68967	1507	opt = opts[c];
hexley	0:281d6ff68967	1508	switch (opt) {
hexley	0:281d6ff68967	1509	case 0x00:
hexley	0:281d6ff68967	1510	/* End of options. */
hexley	0:281d6ff68967	1511	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
hexley	0:281d6ff68967	1512	return;
hexley	0:281d6ff68967	1513	case 0x01:
hexley	0:281d6ff68967	1514	/* NOP option. */
hexley	0:281d6ff68967	1515	++c;
hexley	0:281d6ff68967	1516	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
hexley	0:281d6ff68967	1517	break;
hexley	0:281d6ff68967	1518	case 0x02:
hexley	0:281d6ff68967	1519	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
hexley	0:281d6ff68967	1520	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
hexley	0:281d6ff68967	1521	/* Bad length */
hexley	0:281d6ff68967	1522	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
hexley	0:281d6ff68967	1523	return;
hexley	0:281d6ff68967	1524	}
hexley	0:281d6ff68967	1525	/* An MSS option with the right option length. */
hexley	0:281d6ff68967	1526	mss = (opts[c + 2] << 8) \| opts[c + 3];
hexley	0:281d6ff68967	1527	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
hexley	0:281d6ff68967	1528	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
hexley	0:281d6ff68967	1529	/* Advance to next option */
hexley	0:281d6ff68967	1530	c += 0x04;
hexley	0:281d6ff68967	1531	break;
hexley	0:281d6ff68967	1532	#if LWIP_TCP_TIMESTAMPS
hexley	0:281d6ff68967	1533	case 0x08:
hexley	0:281d6ff68967	1534	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
hexley	0:281d6ff68967	1535	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
hexley	0:281d6ff68967	1536	/* Bad length */
hexley	0:281d6ff68967	1537	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
hexley	0:281d6ff68967	1538	return;
hexley	0:281d6ff68967	1539	}
hexley	0:281d6ff68967	1540	/* TCP timestamp option with valid length */
hexley	0:281d6ff68967	1541	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
hexley	0:281d6ff68967	1542	(opts[c+4] << 16) \| (opts[c+5] << 24);
hexley	0:281d6ff68967	1543	if (flags & TCP_SYN) {
hexley	0:281d6ff68967	1544	pcb->ts_recent = ntohl(tsval);
hexley	0:281d6ff68967	1545	pcb->flags \|= TF_TIMESTAMP;
hexley	0:281d6ff68967	1546	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
hexley	0:281d6ff68967	1547	pcb->ts_recent = ntohl(tsval);
hexley	0:281d6ff68967	1548	}
hexley	0:281d6ff68967	1549	/* Advance to next option */
hexley	0:281d6ff68967	1550	c += 0x0A;
hexley	0:281d6ff68967	1551	break;
hexley	0:281d6ff68967	1552	#endif
hexley	0:281d6ff68967	1553	default:
hexley	0:281d6ff68967	1554	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
hexley	0:281d6ff68967	1555	if (opts[c + 1] == 0) {
hexley	0:281d6ff68967	1556	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
hexley	0:281d6ff68967	1557	/* If the length field is zero, the options are malformed
hexley	0:281d6ff68967	1558	and we don't process them further. */
hexley	0:281d6ff68967	1559	return;
hexley	0:281d6ff68967	1560	}
hexley	0:281d6ff68967	1561	/* All other options have a length field, so that we easily
hexley	0:281d6ff68967	1562	can skip past them. */
hexley	0:281d6ff68967	1563	c += opts[c + 1];
hexley	0:281d6ff68967	1564	}
hexley	0:281d6ff68967	1565	}
hexley	0:281d6ff68967	1566	}
hexley	0:281d6ff68967	1567	}
hexley	0:281d6ff68967	1568
hexley	0:281d6ff68967	1569	#endif /* LWIP_TCP */

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Type:	Library
Created:	19 Nov 2010
Imports:	44
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	1

lwip/core/tcp_in.c@0:281d6ff68967, 2010-11-19 (annotated)

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