AmpereMeter - Example self-announcing webserver which controls …

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Dirk-Willem van Gulik (NXP/mbed) / Mbed 2 deprecated AmpereMeter

Example self-announcing webserver which controls a servo through a smallHTML userinterface.

lwip/core/tcp_in.c@0:a259777c45a3, 2010-08-14 (annotated)

Committer:: dirkx
Date:: Sat Aug 14 15:56:01 2010 +0000
Revision:: 0:a259777c45a3

Who changed what in which revision?

User	Revision	Line number	New contents of line
dirkx	0:a259777c45a3	1	/**
dirkx	0:a259777c45a3	2	* @file
dirkx	0:a259777c45a3	3	* Transmission Control Protocol, incoming traffic
dirkx	0:a259777c45a3	4	*
dirkx	0:a259777c45a3	5	* The input processing functions of the TCP layer.
dirkx	0:a259777c45a3	6	*
dirkx	0:a259777c45a3	7	* These functions are generally called in the order (ip_input() ->)
dirkx	0:a259777c45a3	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
dirkx	0:a259777c45a3	9	*
dirkx	0:a259777c45a3	10	*/
dirkx	0:a259777c45a3	11
dirkx	0:a259777c45a3	12	/*
dirkx	0:a259777c45a3	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
dirkx	0:a259777c45a3	14	* All rights reserved.
dirkx	0:a259777c45a3	15	*
dirkx	0:a259777c45a3	16	* Redistribution and use in source and binary forms, with or without modification,
dirkx	0:a259777c45a3	17	* are permitted provided that the following conditions are met:
dirkx	0:a259777c45a3	18	*
dirkx	0:a259777c45a3	19	* 1. Redistributions of source code must retain the above copyright notice,
dirkx	0:a259777c45a3	20	* this list of conditions and the following disclaimer.
dirkx	0:a259777c45a3	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
dirkx	0:a259777c45a3	22	* this list of conditions and the following disclaimer in the documentation
dirkx	0:a259777c45a3	23	* and/or other materials provided with the distribution.
dirkx	0:a259777c45a3	24	* 3. The name of the author may not be used to endorse or promote products
dirkx	0:a259777c45a3	25	* derived from this software without specific prior written permission.
dirkx	0:a259777c45a3	26	*
dirkx	0:a259777c45a3	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
dirkx	0:a259777c45a3	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
dirkx	0:a259777c45a3	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
dirkx	0:a259777c45a3	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
dirkx	0:a259777c45a3	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
dirkx	0:a259777c45a3	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
dirkx	0:a259777c45a3	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
dirkx	0:a259777c45a3	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
dirkx	0:a259777c45a3	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
dirkx	0:a259777c45a3	36	* OF SUCH DAMAGE.
dirkx	0:a259777c45a3	37	*
dirkx	0:a259777c45a3	38	* This file is part of the lwIP TCP/IP stack.
dirkx	0:a259777c45a3	39	*
dirkx	0:a259777c45a3	40	* Author: Adam Dunkels <adam@sics.se>
dirkx	0:a259777c45a3	41	*
dirkx	0:a259777c45a3	42	*/
dirkx	0:a259777c45a3	43
dirkx	0:a259777c45a3	44	#include "lwip/opt.h"
dirkx	0:a259777c45a3	45
dirkx	0:a259777c45a3	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
dirkx	0:a259777c45a3	47
dirkx	0:a259777c45a3	48	#include "lwip/tcp_impl.h"
dirkx	0:a259777c45a3	49	#include "lwip/def.h"
dirkx	0:a259777c45a3	50	#include "lwip/ip_addr.h"
dirkx	0:a259777c45a3	51	#include "lwip/netif.h"
dirkx	0:a259777c45a3	52	#include "lwip/mem.h"
dirkx	0:a259777c45a3	53	#include "lwip/memp.h"
dirkx	0:a259777c45a3	54	#include "lwip/inet_chksum.h"
dirkx	0:a259777c45a3	55	#include "lwip/stats.h"
dirkx	0:a259777c45a3	56	#include "lwip/snmp.h"
dirkx	0:a259777c45a3	57	#include "arch/perf.h"
dirkx	0:a259777c45a3	58
dirkx	0:a259777c45a3	59	/* These variables are global to all functions involved in the input
dirkx	0:a259777c45a3	60	processing of TCP segments. They are set by the tcp_input()
dirkx	0:a259777c45a3	61	function. */
dirkx	0:a259777c45a3	62	static struct tcp_seg inseg;
dirkx	0:a259777c45a3	63	static struct tcp_hdr *tcphdr;
dirkx	0:a259777c45a3	64	static struct ip_hdr *iphdr;
dirkx	0:a259777c45a3	65	static u32_t seqno, ackno;
dirkx	0:a259777c45a3	66	static u8_t flags;
dirkx	0:a259777c45a3	67	static u16_t tcplen;
dirkx	0:a259777c45a3	68
dirkx	0:a259777c45a3	69	static u8_t recv_flags;
dirkx	0:a259777c45a3	70	static struct pbuf *recv_data;
dirkx	0:a259777c45a3	71
dirkx	0:a259777c45a3	72	struct tcp_pcb *tcp_input_pcb;
dirkx	0:a259777c45a3	73
dirkx	0:a259777c45a3	74	/* Forward declarations. */
dirkx	0:a259777c45a3	75	static err_t tcp_process(struct tcp_pcb *pcb);
dirkx	0:a259777c45a3	76	static void tcp_receive(struct tcp_pcb *pcb);
dirkx	0:a259777c45a3	77	static void tcp_parseopt(struct tcp_pcb *pcb);
dirkx	0:a259777c45a3	78
dirkx	0:a259777c45a3	79	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
dirkx	0:a259777c45a3	80	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
dirkx	0:a259777c45a3	81
dirkx	0:a259777c45a3	82	/**
dirkx	0:a259777c45a3	83	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
dirkx	0:a259777c45a3	84	* the segment between the PCBs and passes it on to tcp_process(), which implements
dirkx	0:a259777c45a3	85	* the TCP finite state machine. This function is called by the IP layer (in
dirkx	0:a259777c45a3	86	* ip_input()).
dirkx	0:a259777c45a3	87	*
dirkx	0:a259777c45a3	88	* @param p received TCP segment to process (p->payload pointing to the IP header)
dirkx	0:a259777c45a3	89	* @param inp network interface on which this segment was received
dirkx	0:a259777c45a3	90	*/
dirkx	0:a259777c45a3	91	void
dirkx	0:a259777c45a3	92	tcp_input(struct pbuf p, struct netif inp)
dirkx	0:a259777c45a3	93	{
dirkx	0:a259777c45a3	94	struct tcp_pcb pcb, prev;
dirkx	0:a259777c45a3	95	struct tcp_pcb_listen *lpcb;
dirkx	0:a259777c45a3	96	u8_t hdrlen;
dirkx	0:a259777c45a3	97	err_t err;
dirkx	0:a259777c45a3	98
dirkx	0:a259777c45a3	99	PERF_START;
dirkx	0:a259777c45a3	100
dirkx	0:a259777c45a3	101	TCP_STATS_INC(tcp.recv);
dirkx	0:a259777c45a3	102	snmp_inc_tcpinsegs();
dirkx	0:a259777c45a3	103
dirkx	0:a259777c45a3	104	iphdr = (struct ip_hdr *)p->payload;
dirkx	0:a259777c45a3	105	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
dirkx	0:a259777c45a3	106
dirkx	0:a259777c45a3	107	#if TCP_INPUT_DEBUG
dirkx	0:a259777c45a3	108	tcp_debug_print(tcphdr);
dirkx	0:a259777c45a3	109	#endif
dirkx	0:a259777c45a3	110
dirkx	0:a259777c45a3	111	/* remove header from payload */
dirkx	0:a259777c45a3	112	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
dirkx	0:a259777c45a3	113	/* drop short packets */
dirkx	0:a259777c45a3	114	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
dirkx	0:a259777c45a3	115	TCP_STATS_INC(tcp.lenerr);
dirkx	0:a259777c45a3	116	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	117	snmp_inc_tcpinerrs();
dirkx	0:a259777c45a3	118	pbuf_free(p);
dirkx	0:a259777c45a3	119	return;
dirkx	0:a259777c45a3	120	}
dirkx	0:a259777c45a3	121
dirkx	0:a259777c45a3	122	/* Don't even process incoming broadcasts/multicasts. */
dirkx	0:a259777c45a3	123	if (ip_addr_isbroadcast(&(iphdr->dest), inp) \|\|
dirkx	0:a259777c45a3	124	ip_addr_ismulticast(&(iphdr->dest))) {
dirkx	0:a259777c45a3	125	TCP_STATS_INC(tcp.proterr);
dirkx	0:a259777c45a3	126	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	127	snmp_inc_tcpinerrs();
dirkx	0:a259777c45a3	128	pbuf_free(p);
dirkx	0:a259777c45a3	129	return;
dirkx	0:a259777c45a3	130	}
dirkx	0:a259777c45a3	131
dirkx	0:a259777c45a3	132	#if CHECKSUM_CHECK_TCP
dirkx	0:a259777c45a3	133	/* Verify TCP checksum. */
dirkx	0:a259777c45a3	134	if (inet_chksum_pseudo(p, &iphdr->src, &iphdr->dest,
dirkx	0:a259777c45a3	135	IP_PROTO_TCP, p->tot_len) != 0) {
dirkx	0:a259777c45a3	136	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
dirkx	0:a259777c45a3	137	inet_chksum_pseudo(p, &iphdr->src, &iphdr->dest,
dirkx	0:a259777c45a3	138	IP_PROTO_TCP, p->tot_len)));
dirkx	0:a259777c45a3	139	#if TCP_DEBUG
dirkx	0:a259777c45a3	140	tcp_debug_print(tcphdr);
dirkx	0:a259777c45a3	141	#endif /* TCP_DEBUG */
dirkx	0:a259777c45a3	142	TCP_STATS_INC(tcp.chkerr);
dirkx	0:a259777c45a3	143	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	144	snmp_inc_tcpinerrs();
dirkx	0:a259777c45a3	145	pbuf_free(p);
dirkx	0:a259777c45a3	146	return;
dirkx	0:a259777c45a3	147	}
dirkx	0:a259777c45a3	148	#endif
dirkx	0:a259777c45a3	149
dirkx	0:a259777c45a3	150	/* Move the payload pointer in the pbuf so that it points to the
dirkx	0:a259777c45a3	151	TCP data instead of the TCP header. */
dirkx	0:a259777c45a3	152	hdrlen = TCPH_HDRLEN(tcphdr);
dirkx	0:a259777c45a3	153	if(pbuf_header(p, -(hdrlen * 4))){
dirkx	0:a259777c45a3	154	/* drop short packets */
dirkx	0:a259777c45a3	155	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
dirkx	0:a259777c45a3	156	TCP_STATS_INC(tcp.lenerr);
dirkx	0:a259777c45a3	157	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	158	snmp_inc_tcpinerrs();
dirkx	0:a259777c45a3	159	pbuf_free(p);
dirkx	0:a259777c45a3	160	return;
dirkx	0:a259777c45a3	161	}
dirkx	0:a259777c45a3	162
dirkx	0:a259777c45a3	163	/* Convert fields in TCP header to host byte order. */
dirkx	0:a259777c45a3	164	tcphdr->src = ntohs(tcphdr->src);
dirkx	0:a259777c45a3	165	tcphdr->dest = ntohs(tcphdr->dest);
dirkx	0:a259777c45a3	166	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
dirkx	0:a259777c45a3	167	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
dirkx	0:a259777c45a3	168	tcphdr->wnd = ntohs(tcphdr->wnd);
dirkx	0:a259777c45a3	169
dirkx	0:a259777c45a3	170	flags = TCPH_FLAGS(tcphdr);
dirkx	0:a259777c45a3	171	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
dirkx	0:a259777c45a3	172
dirkx	0:a259777c45a3	173	/* Demultiplex an incoming segment. First, we check if it is destined
dirkx	0:a259777c45a3	174	for an active connection. */
dirkx	0:a259777c45a3	175	prev = NULL;
dirkx	0:a259777c45a3	176
dirkx	0:a259777c45a3	177
dirkx	0:a259777c45a3	178	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
dirkx	0:a259777c45a3	179	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
dirkx	0:a259777c45a3	180	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
dirkx	0:a259777c45a3	181	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
dirkx	0:a259777c45a3	182	if (pcb->remote_port == tcphdr->src &&
dirkx	0:a259777c45a3	183	pcb->local_port == tcphdr->dest &&
dirkx	0:a259777c45a3	184	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
dirkx	0:a259777c45a3	185	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
dirkx	0:a259777c45a3	186
dirkx	0:a259777c45a3	187	/* Move this PCB to the front of the list so that subsequent
dirkx	0:a259777c45a3	188	lookups will be faster (we exploit locality in TCP segment
dirkx	0:a259777c45a3	189	arrivals). */
dirkx	0:a259777c45a3	190	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
dirkx	0:a259777c45a3	191	if (prev != NULL) {
dirkx	0:a259777c45a3	192	prev->next = pcb->next;
dirkx	0:a259777c45a3	193	pcb->next = tcp_active_pcbs;
dirkx	0:a259777c45a3	194	tcp_active_pcbs = pcb;
dirkx	0:a259777c45a3	195	}
dirkx	0:a259777c45a3	196	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
dirkx	0:a259777c45a3	197	break;
dirkx	0:a259777c45a3	198	}
dirkx	0:a259777c45a3	199	prev = pcb;
dirkx	0:a259777c45a3	200	}
dirkx	0:a259777c45a3	201
dirkx	0:a259777c45a3	202	if (pcb == NULL) {
dirkx	0:a259777c45a3	203	/* If it did not go to an active connection, we check the connections
dirkx	0:a259777c45a3	204	in the TIME-WAIT state. */
dirkx	0:a259777c45a3	205	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
dirkx	0:a259777c45a3	206	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
dirkx	0:a259777c45a3	207	if (pcb->remote_port == tcphdr->src &&
dirkx	0:a259777c45a3	208	pcb->local_port == tcphdr->dest &&
dirkx	0:a259777c45a3	209	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
dirkx	0:a259777c45a3	210	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
dirkx	0:a259777c45a3	211	/* We don't really care enough to move this PCB to the front
dirkx	0:a259777c45a3	212	of the list since we are not very likely to receive that
dirkx	0:a259777c45a3	213	many segments for connections in TIME-WAIT. */
dirkx	0:a259777c45a3	214	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
dirkx	0:a259777c45a3	215	tcp_timewait_input(pcb);
dirkx	0:a259777c45a3	216	pbuf_free(p);
dirkx	0:a259777c45a3	217	return;
dirkx	0:a259777c45a3	218	}
dirkx	0:a259777c45a3	219	}
dirkx	0:a259777c45a3	220
dirkx	0:a259777c45a3	221	/* Finally, if we still did not get a match, we check all PCBs that
dirkx	0:a259777c45a3	222	are LISTENing for incoming connections. */
dirkx	0:a259777c45a3	223	prev = NULL;
dirkx	0:a259777c45a3	224	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
dirkx	0:a259777c45a3	225	if ((ip_addr_isany(&(lpcb->local_ip)) \|\|
dirkx	0:a259777c45a3	226	ip_addr_cmp(&(lpcb->local_ip), &(iphdr->dest))) &&
dirkx	0:a259777c45a3	227	lpcb->local_port == tcphdr->dest) {
dirkx	0:a259777c45a3	228	/* Move this PCB to the front of the list so that subsequent
dirkx	0:a259777c45a3	229	lookups will be faster (we exploit locality in TCP segment
dirkx	0:a259777c45a3	230	arrivals). */
dirkx	0:a259777c45a3	231	if (prev != NULL) {
dirkx	0:a259777c45a3	232	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
dirkx	0:a259777c45a3	233	/* our successor is the remainder of the listening list */
dirkx	0:a259777c45a3	234	lpcb->next = tcp_listen_pcbs.listen_pcbs;
dirkx	0:a259777c45a3	235	/* put this listening pcb at the head of the listening list */
dirkx	0:a259777c45a3	236	tcp_listen_pcbs.listen_pcbs = lpcb;
dirkx	0:a259777c45a3	237	}
dirkx	0:a259777c45a3	238
dirkx	0:a259777c45a3	239	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
dirkx	0:a259777c45a3	240	tcp_listen_input(lpcb);
dirkx	0:a259777c45a3	241	pbuf_free(p);
dirkx	0:a259777c45a3	242	return;
dirkx	0:a259777c45a3	243	}
dirkx	0:a259777c45a3	244	prev = (struct tcp_pcb *)lpcb;
dirkx	0:a259777c45a3	245	}
dirkx	0:a259777c45a3	246	}
dirkx	0:a259777c45a3	247
dirkx	0:a259777c45a3	248	#if TCP_INPUT_DEBUG
dirkx	0:a259777c45a3	249	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
dirkx	0:a259777c45a3	250	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
dirkx	0:a259777c45a3	251	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
dirkx	0:a259777c45a3	252	#endif /* TCP_INPUT_DEBUG */
dirkx	0:a259777c45a3	253
dirkx	0:a259777c45a3	254
dirkx	0:a259777c45a3	255	if (pcb != NULL) {
dirkx	0:a259777c45a3	256	/* The incoming segment belongs to a connection. */
dirkx	0:a259777c45a3	257	#if TCP_INPUT_DEBUG
dirkx	0:a259777c45a3	258	#if TCP_DEBUG
dirkx	0:a259777c45a3	259	tcp_debug_print_state(pcb->state);
dirkx	0:a259777c45a3	260	#endif /* TCP_DEBUG */
dirkx	0:a259777c45a3	261	#endif /* TCP_INPUT_DEBUG */
dirkx	0:a259777c45a3	262
dirkx	0:a259777c45a3	263	/* Set up a tcp_seg structure. */
dirkx	0:a259777c45a3	264	inseg.next = NULL;
dirkx	0:a259777c45a3	265	inseg.len = p->tot_len;
dirkx	0:a259777c45a3	266	inseg.dataptr = p->payload;
dirkx	0:a259777c45a3	267	inseg.p = p;
dirkx	0:a259777c45a3	268	inseg.tcphdr = tcphdr;
dirkx	0:a259777c45a3	269
dirkx	0:a259777c45a3	270	recv_data = NULL;
dirkx	0:a259777c45a3	271	recv_flags = 0;
dirkx	0:a259777c45a3	272
dirkx	0:a259777c45a3	273	/* If there is data which was previously "refused" by upper layer */
dirkx	0:a259777c45a3	274	if (pcb->refused_data != NULL) {
dirkx	0:a259777c45a3	275	/* Notify again application with data previously received. */
dirkx	0:a259777c45a3	276	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
dirkx	0:a259777c45a3	277	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
dirkx	0:a259777c45a3	278	if (err == ERR_OK) {
dirkx	0:a259777c45a3	279	pcb->refused_data = NULL;
dirkx	0:a259777c45a3	280	} else {
dirkx	0:a259777c45a3	281	/* if err == ERR_ABRT, 'pcb' is already deallocated */
dirkx	0:a259777c45a3	282	/* drop incoming packets, because pcb is "full" */
dirkx	0:a259777c45a3	283	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
dirkx	0:a259777c45a3	284	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	285	snmp_inc_tcpinerrs();
dirkx	0:a259777c45a3	286	pbuf_free(p);
dirkx	0:a259777c45a3	287	return;
dirkx	0:a259777c45a3	288	}
dirkx	0:a259777c45a3	289	}
dirkx	0:a259777c45a3	290	tcp_input_pcb = pcb;
dirkx	0:a259777c45a3	291	err = tcp_process(pcb);
dirkx	0:a259777c45a3	292	/* A return value of ERR_ABRT means that tcp_abort() was called
dirkx	0:a259777c45a3	293	and that the pcb has been freed. If so, we don't do anything. */
dirkx	0:a259777c45a3	294	if (err != ERR_ABRT) {
dirkx	0:a259777c45a3	295	if (recv_flags & TF_RESET) {
dirkx	0:a259777c45a3	296	/* TF_RESET means that the connection was reset by the other
dirkx	0:a259777c45a3	297	end. We then call the error callback to inform the
dirkx	0:a259777c45a3	298	application that the connection is dead before we
dirkx	0:a259777c45a3	299	deallocate the PCB. */
dirkx	0:a259777c45a3	300	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
dirkx	0:a259777c45a3	301	tcp_pcb_remove(&tcp_active_pcbs, pcb);
dirkx	0:a259777c45a3	302	memp_free(MEMP_TCP_PCB, pcb);
dirkx	0:a259777c45a3	303	} else if (recv_flags & TF_CLOSED) {
dirkx	0:a259777c45a3	304	/* The connection has been closed and we will deallocate the
dirkx	0:a259777c45a3	305	PCB. */
dirkx	0:a259777c45a3	306	tcp_pcb_remove(&tcp_active_pcbs, pcb);
dirkx	0:a259777c45a3	307	memp_free(MEMP_TCP_PCB, pcb);
dirkx	0:a259777c45a3	308	} else {
dirkx	0:a259777c45a3	309	err = ERR_OK;
dirkx	0:a259777c45a3	310	/* If the application has registered a "sent" function to be
dirkx	0:a259777c45a3	311	called when new send buffer space is available, we call it
dirkx	0:a259777c45a3	312	now. */
dirkx	0:a259777c45a3	313	if (pcb->acked > 0) {
dirkx	0:a259777c45a3	314	TCP_EVENT_SENT(pcb, pcb->acked, err);
dirkx	0:a259777c45a3	315	if (err == ERR_ABRT) {
dirkx	0:a259777c45a3	316	goto aborted;
dirkx	0:a259777c45a3	317	}
dirkx	0:a259777c45a3	318	}
dirkx	0:a259777c45a3	319
dirkx	0:a259777c45a3	320	if (recv_data != NULL) {
dirkx	0:a259777c45a3	321	if(flags & TCP_PSH) {
dirkx	0:a259777c45a3	322	recv_data->flags \|= PBUF_FLAG_PUSH;
dirkx	0:a259777c45a3	323	}
dirkx	0:a259777c45a3	324
dirkx	0:a259777c45a3	325	/* Notify application that data has been received. */
dirkx	0:a259777c45a3	326	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
dirkx	0:a259777c45a3	327	if (err == ERR_ABRT) {
dirkx	0:a259777c45a3	328	goto aborted;
dirkx	0:a259777c45a3	329	}
dirkx	0:a259777c45a3	330
dirkx	0:a259777c45a3	331	/* If the upper layer can't receive this data, store it */
dirkx	0:a259777c45a3	332	if (err != ERR_OK) {
dirkx	0:a259777c45a3	333	pcb->refused_data = recv_data;
dirkx	0:a259777c45a3	334	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
dirkx	0:a259777c45a3	335	}
dirkx	0:a259777c45a3	336	}
dirkx	0:a259777c45a3	337
dirkx	0:a259777c45a3	338	/* If a FIN segment was received, we call the callback
dirkx	0:a259777c45a3	339	function with a NULL buffer to indicate EOF. */
dirkx	0:a259777c45a3	340	if (recv_flags & TF_GOT_FIN) {
dirkx	0:a259777c45a3	341	/* correct rcv_wnd as the application won't call tcp_recved()
dirkx	0:a259777c45a3	342	for the FIN's seqno */
dirkx	0:a259777c45a3	343	if (pcb->rcv_wnd != TCP_WND) {
dirkx	0:a259777c45a3	344	pcb->rcv_wnd++;
dirkx	0:a259777c45a3	345	}
dirkx	0:a259777c45a3	346	TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
dirkx	0:a259777c45a3	347	if (err == ERR_ABRT) {
dirkx	0:a259777c45a3	348	goto aborted;
dirkx	0:a259777c45a3	349	}
dirkx	0:a259777c45a3	350	}
dirkx	0:a259777c45a3	351
dirkx	0:a259777c45a3	352	tcp_input_pcb = NULL;
dirkx	0:a259777c45a3	353	/* Try to send something out. */
dirkx	0:a259777c45a3	354	tcp_output(pcb);
dirkx	0:a259777c45a3	355	#if TCP_INPUT_DEBUG
dirkx	0:a259777c45a3	356	#if TCP_DEBUG
dirkx	0:a259777c45a3	357	tcp_debug_print_state(pcb->state);
dirkx	0:a259777c45a3	358	#endif /* TCP_DEBUG */
dirkx	0:a259777c45a3	359	#endif /* TCP_INPUT_DEBUG */
dirkx	0:a259777c45a3	360	}
dirkx	0:a259777c45a3	361	}
dirkx	0:a259777c45a3	362	/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
dirkx	0:a259777c45a3	363	Below this line, 'pcb' may not be dereferenced! */
dirkx	0:a259777c45a3	364	aborted:
dirkx	0:a259777c45a3	365	tcp_input_pcb = NULL;
dirkx	0:a259777c45a3	366
dirkx	0:a259777c45a3	367
dirkx	0:a259777c45a3	368	/* give up our reference to inseg.p */
dirkx	0:a259777c45a3	369	if (inseg.p != NULL)
dirkx	0:a259777c45a3	370	{
dirkx	0:a259777c45a3	371	pbuf_free(inseg.p);
dirkx	0:a259777c45a3	372	inseg.p = NULL;
dirkx	0:a259777c45a3	373	}
dirkx	0:a259777c45a3	374	} else {
dirkx	0:a259777c45a3	375
dirkx	0:a259777c45a3	376	/* If no matching PCB was found, send a TCP RST (reset) to the
dirkx	0:a259777c45a3	377	sender. */
dirkx	0:a259777c45a3	378	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
dirkx	0:a259777c45a3	379	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
dirkx	0:a259777c45a3	380	TCP_STATS_INC(tcp.proterr);
dirkx	0:a259777c45a3	381	TCP_STATS_INC(tcp.drop);
dirkx	0:a259777c45a3	382	tcp_rst(ackno, seqno + tcplen,
dirkx	0:a259777c45a3	383	&(iphdr->dest), &(iphdr->src),
dirkx	0:a259777c45a3	384	tcphdr->dest, tcphdr->src);
dirkx	0:a259777c45a3	385	}
dirkx	0:a259777c45a3	386	pbuf_free(p);
dirkx	0:a259777c45a3	387	}
dirkx	0:a259777c45a3	388
dirkx	0:a259777c45a3	389	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
dirkx	0:a259777c45a3	390	PERF_STOP("tcp_input");
dirkx	0:a259777c45a3	391	}
dirkx	0:a259777c45a3	392
dirkx	0:a259777c45a3	393	/**
dirkx	0:a259777c45a3	394	* Called by tcp_input() when a segment arrives for a listening
dirkx	0:a259777c45a3	395	* connection (from tcp_input()).
dirkx	0:a259777c45a3	396	*
dirkx	0:a259777c45a3	397	* @param pcb the tcp_pcb_listen for which a segment arrived
dirkx	0:a259777c45a3	398	* @return ERR_OK if the segment was processed
dirkx	0:a259777c45a3	399	* another err_t on error
dirkx	0:a259777c45a3	400	*
dirkx	0:a259777c45a3	401	* @note the return value is not (yet?) used in tcp_input()
dirkx	0:a259777c45a3	402	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:a259777c45a3	403	* involved is passed as a parameter to this function
dirkx	0:a259777c45a3	404	*/
dirkx	0:a259777c45a3	405	static err_t
dirkx	0:a259777c45a3	406	tcp_listen_input(struct tcp_pcb_listen *pcb)
dirkx	0:a259777c45a3	407	{
dirkx	0:a259777c45a3	408	struct tcp_pcb *npcb;
dirkx	0:a259777c45a3	409	err_t rc;
dirkx	0:a259777c45a3	410
dirkx	0:a259777c45a3	411	/* In the LISTEN state, we check for incoming SYN segments,
dirkx	0:a259777c45a3	412	creates a new PCB, and responds with a SYN\|ACK. */
dirkx	0:a259777c45a3	413	if (flags & TCP_ACK) {
dirkx	0:a259777c45a3	414	/* For incoming segments with the ACK flag set, respond with a
dirkx	0:a259777c45a3	415	RST. */
dirkx	0:a259777c45a3	416	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
dirkx	0:a259777c45a3	417	tcp_rst(ackno + 1, seqno + tcplen,
dirkx	0:a259777c45a3	418	&(iphdr->dest), &(iphdr->src),
dirkx	0:a259777c45a3	419	tcphdr->dest, tcphdr->src);
dirkx	0:a259777c45a3	420	} else if (flags & TCP_SYN) {
dirkx	0:a259777c45a3	421	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
dirkx	0:a259777c45a3	422	#if TCP_LISTEN_BACKLOG
dirkx	0:a259777c45a3	423	if (pcb->accepts_pending >= pcb->backlog) {
dirkx	0:a259777c45a3	424	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
dirkx	0:a259777c45a3	425	return ERR_ABRT;
dirkx	0:a259777c45a3	426	}
dirkx	0:a259777c45a3	427	#endif /* TCP_LISTEN_BACKLOG */
dirkx	0:a259777c45a3	428	npcb = tcp_alloc(pcb->prio);
dirkx	0:a259777c45a3	429	/* If a new PCB could not be created (probably due to lack of memory),
dirkx	0:a259777c45a3	430	we don't do anything, but rely on the sender will retransmit the
dirkx	0:a259777c45a3	431	SYN at a time when we have more memory available. */
dirkx	0:a259777c45a3	432	if (npcb == NULL) {
dirkx	0:a259777c45a3	433	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
dirkx	0:a259777c45a3	434	TCP_STATS_INC(tcp.memerr);
dirkx	0:a259777c45a3	435	return ERR_MEM;
dirkx	0:a259777c45a3	436	}
dirkx	0:a259777c45a3	437	#if TCP_LISTEN_BACKLOG
dirkx	0:a259777c45a3	438	pcb->accepts_pending++;
dirkx	0:a259777c45a3	439	#endif /* TCP_LISTEN_BACKLOG */
dirkx	0:a259777c45a3	440	/* Set up the new PCB. */
dirkx	0:a259777c45a3	441	ip_addr_copy(npcb->local_ip, iphdr->dest);
dirkx	0:a259777c45a3	442	npcb->local_port = pcb->local_port;
dirkx	0:a259777c45a3	443	ip_addr_copy(npcb->remote_ip, iphdr->src);
dirkx	0:a259777c45a3	444	npcb->remote_port = tcphdr->src;
dirkx	0:a259777c45a3	445	npcb->state = SYN_RCVD;
dirkx	0:a259777c45a3	446	npcb->rcv_nxt = seqno + 1;
dirkx	0:a259777c45a3	447	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
dirkx	0:a259777c45a3	448	npcb->snd_wnd = tcphdr->wnd;
dirkx	0:a259777c45a3	449	npcb->ssthresh = npcb->snd_wnd;
dirkx	0:a259777c45a3	450	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
dirkx	0:a259777c45a3	451	npcb->callback_arg = pcb->callback_arg;
dirkx	0:a259777c45a3	452	#if LWIP_CALLBACK_API
dirkx	0:a259777c45a3	453	npcb->accept = pcb->accept;
dirkx	0:a259777c45a3	454	#endif /* LWIP_CALLBACK_API */
dirkx	0:a259777c45a3	455	/* inherit socket options */
dirkx	0:a259777c45a3	456	npcb->so_options = pcb->so_options & (SOF_DEBUG\|SOF_DONTROUTE\|SOF_KEEPALIVE\|SOF_OOBINLINE\|SOF_LINGER);
dirkx	0:a259777c45a3	457	/* Register the new PCB so that we can begin receiving segments
dirkx	0:a259777c45a3	458	for it. */
dirkx	0:a259777c45a3	459	TCP_REG(&tcp_active_pcbs, npcb);
dirkx	0:a259777c45a3	460
dirkx	0:a259777c45a3	461	/* Parse any options in the SYN. */
dirkx	0:a259777c45a3	462	tcp_parseopt(npcb);
dirkx	0:a259777c45a3	463	#if TCP_CALCULATE_EFF_SEND_MSS
dirkx	0:a259777c45a3	464	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
dirkx	0:a259777c45a3	465	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
dirkx	0:a259777c45a3	466
dirkx	0:a259777c45a3	467	snmp_inc_tcppassiveopens();
dirkx	0:a259777c45a3	468
dirkx	0:a259777c45a3	469	/* Send a SYN\|ACK together with the MSS option. */
dirkx	0:a259777c45a3	470	rc = tcp_enqueue_flags(npcb, TCP_SYN \| TCP_ACK);
dirkx	0:a259777c45a3	471	if (rc != ERR_OK) {
dirkx	0:a259777c45a3	472	tcp_abandon(npcb, 0);
dirkx	0:a259777c45a3	473	return rc;
dirkx	0:a259777c45a3	474	}
dirkx	0:a259777c45a3	475	return tcp_output(npcb);
dirkx	0:a259777c45a3	476	}
dirkx	0:a259777c45a3	477	return ERR_OK;
dirkx	0:a259777c45a3	478	}
dirkx	0:a259777c45a3	479
dirkx	0:a259777c45a3	480	/**
dirkx	0:a259777c45a3	481	* Called by tcp_input() when a segment arrives for a connection in
dirkx	0:a259777c45a3	482	* TIME_WAIT.
dirkx	0:a259777c45a3	483	*
dirkx	0:a259777c45a3	484	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:a259777c45a3	485	*
dirkx	0:a259777c45a3	486	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:a259777c45a3	487	* involved is passed as a parameter to this function
dirkx	0:a259777c45a3	488	*/
dirkx	0:a259777c45a3	489	static err_t
dirkx	0:a259777c45a3	490	tcp_timewait_input(struct tcp_pcb *pcb)
dirkx	0:a259777c45a3	491	{
dirkx	0:a259777c45a3	492	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
dirkx	0:a259777c45a3	493	/* RFC 793 3.9 Event Processing - Segment Arrives:
dirkx	0:a259777c45a3	494	* - first check sequence number - we skip that one in TIME_WAIT (always
dirkx	0:a259777c45a3	495	* acceptable since we only send ACKs)
dirkx	0:a259777c45a3	496	* - second check the RST bit (... return) */
dirkx	0:a259777c45a3	497	if (flags & TCP_RST) {
dirkx	0:a259777c45a3	498	return ERR_OK;
dirkx	0:a259777c45a3	499	}
dirkx	0:a259777c45a3	500	/* - fourth, check the SYN bit, */
dirkx	0:a259777c45a3	501	if (flags & TCP_SYN) {
dirkx	0:a259777c45a3	502	/* If an incoming segment is not acceptable, an acknowledgment
dirkx	0:a259777c45a3	503	should be sent in reply */
dirkx	0:a259777c45a3	504	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
dirkx	0:a259777c45a3	505	/* If the SYN is in the window it is an error, send a reset */
dirkx	0:a259777c45a3	506	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:a259777c45a3	507	tcphdr->dest, tcphdr->src);
dirkx	0:a259777c45a3	508	return ERR_OK;
dirkx	0:a259777c45a3	509	}
dirkx	0:a259777c45a3	510	} else if (flags & TCP_FIN) {
dirkx	0:a259777c45a3	511	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
dirkx	0:a259777c45a3	512	Restart the 2 MSL time-wait timeout.*/
dirkx	0:a259777c45a3	513	pcb->tmr = tcp_ticks;
dirkx	0:a259777c45a3	514	}
dirkx	0:a259777c45a3	515
dirkx	0:a259777c45a3	516	if ((tcplen > 0)) {
dirkx	0:a259777c45a3	517	/* Acknowledge data, FIN or out-of-window SYN */
dirkx	0:a259777c45a3	518	pcb->flags \|= TF_ACK_NOW;
dirkx	0:a259777c45a3	519	return tcp_output(pcb);
dirkx	0:a259777c45a3	520	}
dirkx	0:a259777c45a3	521	return ERR_OK;
dirkx	0:a259777c45a3	522	}
dirkx	0:a259777c45a3	523
dirkx	0:a259777c45a3	524	/**
dirkx	0:a259777c45a3	525	* Implements the TCP state machine. Called by tcp_input. In some
dirkx	0:a259777c45a3	526	* states tcp_receive() is called to receive data. The tcp_seg
dirkx	0:a259777c45a3	527	* argument will be freed by the caller (tcp_input()) unless the
dirkx	0:a259777c45a3	528	* recv_data pointer in the pcb is set.
dirkx	0:a259777c45a3	529	*
dirkx	0:a259777c45a3	530	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:a259777c45a3	531	*
dirkx	0:a259777c45a3	532	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:a259777c45a3	533	* involved is passed as a parameter to this function
dirkx	0:a259777c45a3	534	*/
dirkx	0:a259777c45a3	535	static err_t
dirkx	0:a259777c45a3	536	tcp_process(struct tcp_pcb *pcb)
dirkx	0:a259777c45a3	537	{
dirkx	0:a259777c45a3	538	struct tcp_seg *rseg;
dirkx	0:a259777c45a3	539	u8_t acceptable = 0;
dirkx	0:a259777c45a3	540	err_t err;
dirkx	0:a259777c45a3	541
dirkx	0:a259777c45a3	542	err = ERR_OK;
dirkx	0:a259777c45a3	543
dirkx	0:a259777c45a3	544	/* Process incoming RST segments. */
dirkx	0:a259777c45a3	545	if (flags & TCP_RST) {
dirkx	0:a259777c45a3	546	/* First, determine if the reset is acceptable. */
dirkx	0:a259777c45a3	547	if (pcb->state == SYN_SENT) {
dirkx	0:a259777c45a3	548	if (ackno == pcb->snd_nxt) {
dirkx	0:a259777c45a3	549	acceptable = 1;
dirkx	0:a259777c45a3	550	}
dirkx	0:a259777c45a3	551	} else {
dirkx	0:a259777c45a3	552	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
dirkx	0:a259777c45a3	553	pcb->rcv_nxt+pcb->rcv_wnd)) {
dirkx	0:a259777c45a3	554	acceptable = 1;
dirkx	0:a259777c45a3	555	}
dirkx	0:a259777c45a3	556	}
dirkx	0:a259777c45a3	557
dirkx	0:a259777c45a3	558	if (acceptable) {
dirkx	0:a259777c45a3	559	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
dirkx	0:a259777c45a3	560	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
dirkx	0:a259777c45a3	561	recv_flags \|= TF_RESET;
dirkx	0:a259777c45a3	562	pcb->flags &= ~TF_ACK_DELAY;
dirkx	0:a259777c45a3	563	return ERR_RST;
dirkx	0:a259777c45a3	564	} else {
dirkx	0:a259777c45a3	565	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
dirkx	0:a259777c45a3	566	seqno, pcb->rcv_nxt));
dirkx	0:a259777c45a3	567	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
dirkx	0:a259777c45a3	568	seqno, pcb->rcv_nxt));
dirkx	0:a259777c45a3	569	return ERR_OK;
dirkx	0:a259777c45a3	570	}
dirkx	0:a259777c45a3	571	}
dirkx	0:a259777c45a3	572
dirkx	0:a259777c45a3	573	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
dirkx	0:a259777c45a3	574	/* Cope with new connection attempt after remote end crashed */
dirkx	0:a259777c45a3	575	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	576	return ERR_OK;
dirkx	0:a259777c45a3	577	}
dirkx	0:a259777c45a3	578
dirkx	0:a259777c45a3	579	if ((pcb->flags & TF_RXCLOSED) == 0) {
dirkx	0:a259777c45a3	580	/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
dirkx	0:a259777c45a3	581	pcb->tmr = tcp_ticks;
dirkx	0:a259777c45a3	582	}
dirkx	0:a259777c45a3	583	pcb->keep_cnt_sent = 0;
dirkx	0:a259777c45a3	584
dirkx	0:a259777c45a3	585	tcp_parseopt(pcb);
dirkx	0:a259777c45a3	586
dirkx	0:a259777c45a3	587	/* Do different things depending on the TCP state. */
dirkx	0:a259777c45a3	588	switch (pcb->state) {
dirkx	0:a259777c45a3	589	case SYN_SENT:
dirkx	0:a259777c45a3	590	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
dirkx	0:a259777c45a3	591	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
dirkx	0:a259777c45a3	592	/* received SYN ACK with expected sequence number? */
dirkx	0:a259777c45a3	593	if ((flags & TCP_ACK) && (flags & TCP_SYN)
dirkx	0:a259777c45a3	594	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
dirkx	0:a259777c45a3	595	pcb->snd_buf++;
dirkx	0:a259777c45a3	596	pcb->rcv_nxt = seqno + 1;
dirkx	0:a259777c45a3	597	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
dirkx	0:a259777c45a3	598	pcb->lastack = ackno;
dirkx	0:a259777c45a3	599	pcb->snd_wnd = tcphdr->wnd;
dirkx	0:a259777c45a3	600	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
dirkx	0:a259777c45a3	601	pcb->state = ESTABLISHED;
dirkx	0:a259777c45a3	602
dirkx	0:a259777c45a3	603	#if TCP_CALCULATE_EFF_SEND_MSS
dirkx	0:a259777c45a3	604	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
dirkx	0:a259777c45a3	605	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
dirkx	0:a259777c45a3	606
dirkx	0:a259777c45a3	607	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
dirkx	0:a259777c45a3	608	* but for the default value of pcb->mss) */
dirkx	0:a259777c45a3	609	pcb->ssthresh = pcb->mss * 10;
dirkx	0:a259777c45a3	610
dirkx	0:a259777c45a3	611	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
dirkx	0:a259777c45a3	612	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
dirkx	0:a259777c45a3	613	--pcb->snd_queuelen;
dirkx	0:a259777c45a3	614	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
dirkx	0:a259777c45a3	615	rseg = pcb->unacked;
dirkx	0:a259777c45a3	616	pcb->unacked = rseg->next;
dirkx	0:a259777c45a3	617
dirkx	0:a259777c45a3	618	/* If there's nothing left to acknowledge, stop the retransmit
dirkx	0:a259777c45a3	619	timer, otherwise reset it to start again */
dirkx	0:a259777c45a3	620	if(pcb->unacked == NULL)
dirkx	0:a259777c45a3	621	pcb->rtime = -1;
dirkx	0:a259777c45a3	622	else {
dirkx	0:a259777c45a3	623	pcb->rtime = 0;
dirkx	0:a259777c45a3	624	pcb->nrtx = 0;
dirkx	0:a259777c45a3	625	}
dirkx	0:a259777c45a3	626
dirkx	0:a259777c45a3	627	tcp_seg_free(rseg);
dirkx	0:a259777c45a3	628
dirkx	0:a259777c45a3	629	/* Call the user specified function to call when sucessfully
dirkx	0:a259777c45a3	630	* connected. */
dirkx	0:a259777c45a3	631	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
dirkx	0:a259777c45a3	632	if (err == ERR_ABRT) {
dirkx	0:a259777c45a3	633	return ERR_ABRT;
dirkx	0:a259777c45a3	634	}
dirkx	0:a259777c45a3	635	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	636	}
dirkx	0:a259777c45a3	637	/* received ACK? possibly a half-open connection */
dirkx	0:a259777c45a3	638	else if (flags & TCP_ACK) {
dirkx	0:a259777c45a3	639	/* send a RST to bring the other side in a non-synchronized state. */
dirkx	0:a259777c45a3	640	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:a259777c45a3	641	tcphdr->dest, tcphdr->src);
dirkx	0:a259777c45a3	642	}
dirkx	0:a259777c45a3	643	break;
dirkx	0:a259777c45a3	644	case SYN_RCVD:
dirkx	0:a259777c45a3	645	if (flags & TCP_ACK) {
dirkx	0:a259777c45a3	646	/* expected ACK number? */
dirkx	0:a259777c45a3	647	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
dirkx	0:a259777c45a3	648	u16_t old_cwnd;
dirkx	0:a259777c45a3	649	pcb->state = ESTABLISHED;
dirkx	0:a259777c45a3	650	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:a259777c45a3	651	#if LWIP_CALLBACK_API
dirkx	0:a259777c45a3	652	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
dirkx	0:a259777c45a3	653	#endif
dirkx	0:a259777c45a3	654	/* Call the accept function. */
dirkx	0:a259777c45a3	655	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
dirkx	0:a259777c45a3	656	if (err != ERR_OK) {
dirkx	0:a259777c45a3	657	/* If the accept function returns with an error, we abort
dirkx	0:a259777c45a3	658	* the connection. */
dirkx	0:a259777c45a3	659	/* Already aborted? */
dirkx	0:a259777c45a3	660	if (err != ERR_ABRT) {
dirkx	0:a259777c45a3	661	tcp_abort(pcb);
dirkx	0:a259777c45a3	662	}
dirkx	0:a259777c45a3	663	return ERR_ABRT;
dirkx	0:a259777c45a3	664	}
dirkx	0:a259777c45a3	665	old_cwnd = pcb->cwnd;
dirkx	0:a259777c45a3	666	/* If there was any data contained within this ACK,
dirkx	0:a259777c45a3	667	* we'd better pass it on to the application as well. */
dirkx	0:a259777c45a3	668	tcp_receive(pcb);
dirkx	0:a259777c45a3	669
dirkx	0:a259777c45a3	670	/* Prevent ACK for SYN to generate a sent event */
dirkx	0:a259777c45a3	671	if (pcb->acked != 0) {
dirkx	0:a259777c45a3	672	pcb->acked--;
dirkx	0:a259777c45a3	673	}
dirkx	0:a259777c45a3	674
dirkx	0:a259777c45a3	675	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
dirkx	0:a259777c45a3	676
dirkx	0:a259777c45a3	677	if (recv_flags & TF_GOT_FIN) {
dirkx	0:a259777c45a3	678	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	679	pcb->state = CLOSE_WAIT;
dirkx	0:a259777c45a3	680	}
dirkx	0:a259777c45a3	681	} else {
dirkx	0:a259777c45a3	682	/* incorrect ACK number, send RST */
dirkx	0:a259777c45a3	683	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:a259777c45a3	684	tcphdr->dest, tcphdr->src);
dirkx	0:a259777c45a3	685	}
dirkx	0:a259777c45a3	686	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
dirkx	0:a259777c45a3	687	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
dirkx	0:a259777c45a3	688	tcp_rexmit(pcb);
dirkx	0:a259777c45a3	689	}
dirkx	0:a259777c45a3	690	break;
dirkx	0:a259777c45a3	691	case CLOSE_WAIT:
dirkx	0:a259777c45a3	692	/* FALLTHROUGH */
dirkx	0:a259777c45a3	693	case ESTABLISHED:
dirkx	0:a259777c45a3	694	tcp_receive(pcb);
dirkx	0:a259777c45a3	695	if (recv_flags & TF_GOT_FIN) { /* passive close */
dirkx	0:a259777c45a3	696	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	697	pcb->state = CLOSE_WAIT;
dirkx	0:a259777c45a3	698	}
dirkx	0:a259777c45a3	699	break;
dirkx	0:a259777c45a3	700	case FIN_WAIT_1:
dirkx	0:a259777c45a3	701	tcp_receive(pcb);
dirkx	0:a259777c45a3	702	if (recv_flags & TF_GOT_FIN) {
dirkx	0:a259777c45a3	703	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
dirkx	0:a259777c45a3	704	LWIP_DEBUGF(TCP_DEBUG,
dirkx	0:a259777c45a3	705	("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:a259777c45a3	706	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	707	tcp_pcb_purge(pcb);
dirkx	0:a259777c45a3	708	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:a259777c45a3	709	pcb->state = TIME_WAIT;
dirkx	0:a259777c45a3	710	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:a259777c45a3	711	} else {
dirkx	0:a259777c45a3	712	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	713	pcb->state = CLOSING;
dirkx	0:a259777c45a3	714	}
dirkx	0:a259777c45a3	715	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
dirkx	0:a259777c45a3	716	pcb->state = FIN_WAIT_2;
dirkx	0:a259777c45a3	717	}
dirkx	0:a259777c45a3	718	break;
dirkx	0:a259777c45a3	719	case FIN_WAIT_2:
dirkx	0:a259777c45a3	720	tcp_receive(pcb);
dirkx	0:a259777c45a3	721	if (recv_flags & TF_GOT_FIN) {
dirkx	0:a259777c45a3	722	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:a259777c45a3	723	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	724	tcp_pcb_purge(pcb);
dirkx	0:a259777c45a3	725	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:a259777c45a3	726	pcb->state = TIME_WAIT;
dirkx	0:a259777c45a3	727	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:a259777c45a3	728	}
dirkx	0:a259777c45a3	729	break;
dirkx	0:a259777c45a3	730	case CLOSING:
dirkx	0:a259777c45a3	731	tcp_receive(pcb);
dirkx	0:a259777c45a3	732	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
dirkx	0:a259777c45a3	733	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:a259777c45a3	734	tcp_pcb_purge(pcb);
dirkx	0:a259777c45a3	735	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:a259777c45a3	736	pcb->state = TIME_WAIT;
dirkx	0:a259777c45a3	737	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:a259777c45a3	738	}
dirkx	0:a259777c45a3	739	break;
dirkx	0:a259777c45a3	740	case LAST_ACK:
dirkx	0:a259777c45a3	741	tcp_receive(pcb);
dirkx	0:a259777c45a3	742	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
dirkx	0:a259777c45a3	743	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:a259777c45a3	744	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
dirkx	0:a259777c45a3	745	recv_flags \|= TF_CLOSED;
dirkx	0:a259777c45a3	746	}
dirkx	0:a259777c45a3	747	break;
dirkx	0:a259777c45a3	748	default:
dirkx	0:a259777c45a3	749	break;
dirkx	0:a259777c45a3	750	}
dirkx	0:a259777c45a3	751	return ERR_OK;
dirkx	0:a259777c45a3	752	}
dirkx	0:a259777c45a3	753
dirkx	0:a259777c45a3	754	#if TCP_QUEUE_OOSEQ
dirkx	0:a259777c45a3	755	/**
dirkx	0:a259777c45a3	756	* Insert segment into the list (segments covered with new one will be deleted)
dirkx	0:a259777c45a3	757	*
dirkx	0:a259777c45a3	758	* Called from tcp_receive()
dirkx	0:a259777c45a3	759	*/
dirkx	0:a259777c45a3	760	static void
dirkx	0:a259777c45a3	761	tcp_oos_insert_segment(struct tcp_seg cseg, struct tcp_seg next)
dirkx	0:a259777c45a3	762	{
dirkx	0:a259777c45a3	763	struct tcp_seg *old_seg;
dirkx	0:a259777c45a3	764
dirkx	0:a259777c45a3	765	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	766	/* received segment overlaps all following segments */
dirkx	0:a259777c45a3	767	tcp_segs_free(next);
dirkx	0:a259777c45a3	768	next = NULL;
dirkx	0:a259777c45a3	769	}
dirkx	0:a259777c45a3	770	else {
dirkx	0:a259777c45a3	771	/* delete some following segments
dirkx	0:a259777c45a3	772	oos queue may have segments with FIN flag */
dirkx	0:a259777c45a3	773	while (next &&
dirkx	0:a259777c45a3	774	TCP_SEQ_GEQ((seqno + cseg->len),
dirkx	0:a259777c45a3	775	(next->tcphdr->seqno + next->len))) {
dirkx	0:a259777c45a3	776	/* cseg with FIN already processed */
dirkx	0:a259777c45a3	777	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	778	TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
dirkx	0:a259777c45a3	779	}
dirkx	0:a259777c45a3	780	old_seg = next;
dirkx	0:a259777c45a3	781	next = next->next;
dirkx	0:a259777c45a3	782	tcp_seg_free(old_seg);
dirkx	0:a259777c45a3	783	}
dirkx	0:a259777c45a3	784	if (next &&
dirkx	0:a259777c45a3	785	TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
dirkx	0:a259777c45a3	786	/* We need to trim the incoming segment. */
dirkx	0:a259777c45a3	787	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
dirkx	0:a259777c45a3	788	pbuf_realloc(cseg->p, cseg->len);
dirkx	0:a259777c45a3	789	}
dirkx	0:a259777c45a3	790	}
dirkx	0:a259777c45a3	791	cseg->next = next;
dirkx	0:a259777c45a3	792	}
dirkx	0:a259777c45a3	793	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:a259777c45a3	794
dirkx	0:a259777c45a3	795	/**
dirkx	0:a259777c45a3	796	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
dirkx	0:a259777c45a3	797	* data, and if so frees the memory of the buffered data. Next, is places the
dirkx	0:a259777c45a3	798	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
dirkx	0:a259777c45a3	799	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
dirkx	0:a259777c45a3	800	* i it has been removed from the buffer.
dirkx	0:a259777c45a3	801	*
dirkx	0:a259777c45a3	802	* If the incoming segment constitutes an ACK for a segment that was used for RTT
dirkx	0:a259777c45a3	803	* estimation, the RTT is estimated here as well.
dirkx	0:a259777c45a3	804	*
dirkx	0:a259777c45a3	805	* Called from tcp_process().
dirkx	0:a259777c45a3	806	*/
dirkx	0:a259777c45a3	807	static void
dirkx	0:a259777c45a3	808	tcp_receive(struct tcp_pcb *pcb)
dirkx	0:a259777c45a3	809	{
dirkx	0:a259777c45a3	810	struct tcp_seg *next;
dirkx	0:a259777c45a3	811	#if TCP_QUEUE_OOSEQ
dirkx	0:a259777c45a3	812	struct tcp_seg prev, cseg;
dirkx	0:a259777c45a3	813	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:a259777c45a3	814	struct pbuf *p;
dirkx	0:a259777c45a3	815	s32_t off;
dirkx	0:a259777c45a3	816	s16_t m;
dirkx	0:a259777c45a3	817	u32_t right_wnd_edge;
dirkx	0:a259777c45a3	818	u16_t new_tot_len;
dirkx	0:a259777c45a3	819	int found_dupack = 0;
dirkx	0:a259777c45a3	820
dirkx	0:a259777c45a3	821	if (flags & TCP_ACK) {
dirkx	0:a259777c45a3	822	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
dirkx	0:a259777c45a3	823
dirkx	0:a259777c45a3	824	/* Update window. */
dirkx	0:a259777c45a3	825	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
dirkx	0:a259777c45a3	826	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
dirkx	0:a259777c45a3	827	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
dirkx	0:a259777c45a3	828	pcb->snd_wnd = tcphdr->wnd;
dirkx	0:a259777c45a3	829	pcb->snd_wl1 = seqno;
dirkx	0:a259777c45a3	830	pcb->snd_wl2 = ackno;
dirkx	0:a259777c45a3	831	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
dirkx	0:a259777c45a3	832	pcb->persist_backoff = 0;
dirkx	0:a259777c45a3	833	}
dirkx	0:a259777c45a3	834	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
dirkx	0:a259777c45a3	835	#if TCP_WND_DEBUG
dirkx	0:a259777c45a3	836	} else {
dirkx	0:a259777c45a3	837	if (pcb->snd_wnd != tcphdr->wnd) {
dirkx	0:a259777c45a3	838	LWIP_DEBUGF(TCP_WND_DEBUG,
dirkx	0:a259777c45a3	839	("tcp_receive: no window update lastack %"U32_F" ackno %"
dirkx	0:a259777c45a3	840	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
dirkx	0:a259777c45a3	841	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
dirkx	0:a259777c45a3	842	}
dirkx	0:a259777c45a3	843	#endif /* TCP_WND_DEBUG */
dirkx	0:a259777c45a3	844	}
dirkx	0:a259777c45a3	845
dirkx	0:a259777c45a3	846	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
dirkx	0:a259777c45a3	847	* duplicate ack if:
dirkx	0:a259777c45a3	848	* 1) It doesn't ACK new data
dirkx	0:a259777c45a3	849	* 2) length of received packet is zero (i.e. no payload)
dirkx	0:a259777c45a3	850	* 3) the advertised window hasn't changed
dirkx	0:a259777c45a3	851	* 4) There is outstanding unacknowledged data (retransmission timer running)
dirkx	0:a259777c45a3	852	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
dirkx	0:a259777c45a3	853	*
dirkx	0:a259777c45a3	854	* If it passes all five, should process as a dupack:
dirkx	0:a259777c45a3	855	* a) dupacks < 3: do nothing
dirkx	0:a259777c45a3	856	* b) dupacks == 3: fast retransmit
dirkx	0:a259777c45a3	857	* c) dupacks > 3: increase cwnd
dirkx	0:a259777c45a3	858	*
dirkx	0:a259777c45a3	859	* If it only passes 1-3, should reset dupack counter (and add to
dirkx	0:a259777c45a3	860	* stats, which we don't do in lwIP)
dirkx	0:a259777c45a3	861	*
dirkx	0:a259777c45a3	862	* If it only passes 1, should reset dupack counter
dirkx	0:a259777c45a3	863	*
dirkx	0:a259777c45a3	864	*/
dirkx	0:a259777c45a3	865
dirkx	0:a259777c45a3	866	/* Clause 1 */
dirkx	0:a259777c45a3	867	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
dirkx	0:a259777c45a3	868	pcb->acked = 0;
dirkx	0:a259777c45a3	869	/* Clause 2 */
dirkx	0:a259777c45a3	870	if (tcplen == 0) {
dirkx	0:a259777c45a3	871	/* Clause 3 */
dirkx	0:a259777c45a3	872	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
dirkx	0:a259777c45a3	873	/* Clause 4 */
dirkx	0:a259777c45a3	874	if (pcb->rtime >= 0) {
dirkx	0:a259777c45a3	875	/* Clause 5 */
dirkx	0:a259777c45a3	876	if (pcb->lastack == ackno) {
dirkx	0:a259777c45a3	877	found_dupack = 1;
dirkx	0:a259777c45a3	878	if (pcb->dupacks + 1 > pcb->dupacks)
dirkx	0:a259777c45a3	879	++pcb->dupacks;
dirkx	0:a259777c45a3	880	if (pcb->dupacks > 3) {
dirkx	0:a259777c45a3	881	/* Inflate the congestion window, but not if it means that
dirkx	0:a259777c45a3	882	the value overflows. */
dirkx	0:a259777c45a3	883	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
dirkx	0:a259777c45a3	884	pcb->cwnd += pcb->mss;
dirkx	0:a259777c45a3	885	}
dirkx	0:a259777c45a3	886	} else if (pcb->dupacks == 3) {
dirkx	0:a259777c45a3	887	/* Do fast retransmit */
dirkx	0:a259777c45a3	888	tcp_rexmit_fast(pcb);
dirkx	0:a259777c45a3	889	}
dirkx	0:a259777c45a3	890	}
dirkx	0:a259777c45a3	891	}
dirkx	0:a259777c45a3	892	}
dirkx	0:a259777c45a3	893	}
dirkx	0:a259777c45a3	894	/* If Clause (1) or more is true, but not a duplicate ack, reset
dirkx	0:a259777c45a3	895	* count of consecutive duplicate acks */
dirkx	0:a259777c45a3	896	if (!found_dupack) {
dirkx	0:a259777c45a3	897	pcb->dupacks = 0;
dirkx	0:a259777c45a3	898	}
dirkx	0:a259777c45a3	899	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
dirkx	0:a259777c45a3	900	/* We come here when the ACK acknowledges new data. */
dirkx	0:a259777c45a3	901
dirkx	0:a259777c45a3	902	/* Reset the "IN Fast Retransmit" flag, since we are no longer
dirkx	0:a259777c45a3	903	in fast retransmit. Also reset the congestion window to the
dirkx	0:a259777c45a3	904	slow start threshold. */
dirkx	0:a259777c45a3	905	if (pcb->flags & TF_INFR) {
dirkx	0:a259777c45a3	906	pcb->flags &= ~TF_INFR;
dirkx	0:a259777c45a3	907	pcb->cwnd = pcb->ssthresh;
dirkx	0:a259777c45a3	908	}
dirkx	0:a259777c45a3	909
dirkx	0:a259777c45a3	910	/* Reset the number of retransmissions. */
dirkx	0:a259777c45a3	911	pcb->nrtx = 0;
dirkx	0:a259777c45a3	912
dirkx	0:a259777c45a3	913	/* Reset the retransmission time-out. */
dirkx	0:a259777c45a3	914	pcb->rto = (pcb->sa >> 3) + pcb->sv;
dirkx	0:a259777c45a3	915
dirkx	0:a259777c45a3	916	/* Update the send buffer space. Diff between the two can never exceed 64K? */
dirkx	0:a259777c45a3	917	pcb->acked = (u16_t)(ackno - pcb->lastack);
dirkx	0:a259777c45a3	918
dirkx	0:a259777c45a3	919	pcb->snd_buf += pcb->acked;
dirkx	0:a259777c45a3	920
dirkx	0:a259777c45a3	921	/* Reset the fast retransmit variables. */
dirkx	0:a259777c45a3	922	pcb->dupacks = 0;
dirkx	0:a259777c45a3	923	pcb->lastack = ackno;
dirkx	0:a259777c45a3	924
dirkx	0:a259777c45a3	925	/* Update the congestion control variables (cwnd and
dirkx	0:a259777c45a3	926	ssthresh). */
dirkx	0:a259777c45a3	927	if (pcb->state >= ESTABLISHED) {
dirkx	0:a259777c45a3	928	if (pcb->cwnd < pcb->ssthresh) {
dirkx	0:a259777c45a3	929	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
dirkx	0:a259777c45a3	930	pcb->cwnd += pcb->mss;
dirkx	0:a259777c45a3	931	}
dirkx	0:a259777c45a3	932	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
dirkx	0:a259777c45a3	933	} else {
dirkx	0:a259777c45a3	934	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
dirkx	0:a259777c45a3	935	if (new_cwnd > pcb->cwnd) {
dirkx	0:a259777c45a3	936	pcb->cwnd = new_cwnd;
dirkx	0:a259777c45a3	937	}
dirkx	0:a259777c45a3	938	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
dirkx	0:a259777c45a3	939	}
dirkx	0:a259777c45a3	940	}
dirkx	0:a259777c45a3	941	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
dirkx	0:a259777c45a3	942	ackno,
dirkx	0:a259777c45a3	943	pcb->unacked != NULL?
dirkx	0:a259777c45a3	944	ntohl(pcb->unacked->tcphdr->seqno): 0,
dirkx	0:a259777c45a3	945	pcb->unacked != NULL?
dirkx	0:a259777c45a3	946	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
dirkx	0:a259777c45a3	947
dirkx	0:a259777c45a3	948	/* Remove segment from the unacknowledged list if the incoming
dirkx	0:a259777c45a3	949	ACK acknowlegdes them. */
dirkx	0:a259777c45a3	950	while (pcb->unacked != NULL &&
dirkx	0:a259777c45a3	951	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
dirkx	0:a259777c45a3	952	TCP_TCPLEN(pcb->unacked), ackno)) {
dirkx	0:a259777c45a3	953	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
dirkx	0:a259777c45a3	954	ntohl(pcb->unacked->tcphdr->seqno),
dirkx	0:a259777c45a3	955	ntohl(pcb->unacked->tcphdr->seqno) +
dirkx	0:a259777c45a3	956	TCP_TCPLEN(pcb->unacked)));
dirkx	0:a259777c45a3	957
dirkx	0:a259777c45a3	958	next = pcb->unacked;
dirkx	0:a259777c45a3	959	pcb->unacked = pcb->unacked->next;
dirkx	0:a259777c45a3	960
dirkx	0:a259777c45a3	961	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
dirkx	0:a259777c45a3	962	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
dirkx	0:a259777c45a3	963	/* Prevent ACK for FIN to generate a sent event */
dirkx	0:a259777c45a3	964	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
dirkx	0:a259777c45a3	965	pcb->acked--;
dirkx	0:a259777c45a3	966	}
dirkx	0:a259777c45a3	967
dirkx	0:a259777c45a3	968	pcb->snd_queuelen -= pbuf_clen(next->p);
dirkx	0:a259777c45a3	969	tcp_seg_free(next);
dirkx	0:a259777c45a3	970
dirkx	0:a259777c45a3	971	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
dirkx	0:a259777c45a3	972	if (pcb->snd_queuelen != 0) {
dirkx	0:a259777c45a3	973	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
dirkx	0:a259777c45a3	974	pcb->unsent != NULL);
dirkx	0:a259777c45a3	975	}
dirkx	0:a259777c45a3	976	}
dirkx	0:a259777c45a3	977
dirkx	0:a259777c45a3	978	/* If there's nothing left to acknowledge, stop the retransmit
dirkx	0:a259777c45a3	979	timer, otherwise reset it to start again */
dirkx	0:a259777c45a3	980	if(pcb->unacked == NULL)
dirkx	0:a259777c45a3	981	pcb->rtime = -1;
dirkx	0:a259777c45a3	982	else
dirkx	0:a259777c45a3	983	pcb->rtime = 0;
dirkx	0:a259777c45a3	984
dirkx	0:a259777c45a3	985	pcb->polltmr = 0;
dirkx	0:a259777c45a3	986	} else {
dirkx	0:a259777c45a3	987	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
dirkx	0:a259777c45a3	988	pcb->acked = 0;
dirkx	0:a259777c45a3	989	}
dirkx	0:a259777c45a3	990
dirkx	0:a259777c45a3	991	/* We go through the ->unsent list to see if any of the segments
dirkx	0:a259777c45a3	992	on the list are acknowledged by the ACK. This may seem
dirkx	0:a259777c45a3	993	strange since an "unsent" segment shouldn't be acked. The
dirkx	0:a259777c45a3	994	rationale is that lwIP puts all outstanding segments on the
dirkx	0:a259777c45a3	995	->unsent list after a retransmission, so these segments may
dirkx	0:a259777c45a3	996	in fact have been sent once. */
dirkx	0:a259777c45a3	997	while (pcb->unsent != NULL &&
dirkx	0:a259777c45a3	998	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
dirkx	0:a259777c45a3	999	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
dirkx	0:a259777c45a3	1000	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
dirkx	0:a259777c45a3	1001	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
dirkx	0:a259777c45a3	1002	TCP_TCPLEN(pcb->unsent)));
dirkx	0:a259777c45a3	1003
dirkx	0:a259777c45a3	1004	next = pcb->unsent;
dirkx	0:a259777c45a3	1005	pcb->unsent = pcb->unsent->next;
dirkx	0:a259777c45a3	1006	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
dirkx	0:a259777c45a3	1007	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
dirkx	0:a259777c45a3	1008	/* Prevent ACK for FIN to generate a sent event */
dirkx	0:a259777c45a3	1009	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
dirkx	0:a259777c45a3	1010	pcb->acked--;
dirkx	0:a259777c45a3	1011	}
dirkx	0:a259777c45a3	1012	pcb->snd_queuelen -= pbuf_clen(next->p);
dirkx	0:a259777c45a3	1013	tcp_seg_free(next);
dirkx	0:a259777c45a3	1014	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
dirkx	0:a259777c45a3	1015	if (pcb->snd_queuelen != 0) {
dirkx	0:a259777c45a3	1016	LWIP_ASSERT("tcp_receive: valid queue length",
dirkx	0:a259777c45a3	1017	pcb->unacked != NULL \|\| pcb->unsent != NULL);
dirkx	0:a259777c45a3	1018	}
dirkx	0:a259777c45a3	1019	}
dirkx	0:a259777c45a3	1020	/* End of ACK for new data processing. */
dirkx	0:a259777c45a3	1021
dirkx	0:a259777c45a3	1022	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
dirkx	0:a259777c45a3	1023	pcb->rttest, pcb->rtseq, ackno));
dirkx	0:a259777c45a3	1024
dirkx	0:a259777c45a3	1025	/* RTT estimation calculations. This is done by checking if the
dirkx	0:a259777c45a3	1026	incoming segment acknowledges the segment we use to take a
dirkx	0:a259777c45a3	1027	round-trip time measurement. */
dirkx	0:a259777c45a3	1028	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
dirkx	0:a259777c45a3	1029	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
dirkx	0:a259777c45a3	1030	and a round-trip shouldn't be that long... */
dirkx	0:a259777c45a3	1031	m = (s16_t)(tcp_ticks - pcb->rttest);
dirkx	0:a259777c45a3	1032
dirkx	0:a259777c45a3	1033	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
dirkx	0:a259777c45a3	1034	m, m * TCP_SLOW_INTERVAL));
dirkx	0:a259777c45a3	1035
dirkx	0:a259777c45a3	1036	/* This is taken directly from VJs original code in his paper */
dirkx	0:a259777c45a3	1037	m = m - (pcb->sa >> 3);
dirkx	0:a259777c45a3	1038	pcb->sa += m;
dirkx	0:a259777c45a3	1039	if (m < 0) {
dirkx	0:a259777c45a3	1040	m = -m;
dirkx	0:a259777c45a3	1041	}
dirkx	0:a259777c45a3	1042	m = m - (pcb->sv >> 2);
dirkx	0:a259777c45a3	1043	pcb->sv += m;
dirkx	0:a259777c45a3	1044	pcb->rto = (pcb->sa >> 3) + pcb->sv;
dirkx	0:a259777c45a3	1045
dirkx	0:a259777c45a3	1046	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
dirkx	0:a259777c45a3	1047	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
dirkx	0:a259777c45a3	1048
dirkx	0:a259777c45a3	1049	pcb->rttest = 0;
dirkx	0:a259777c45a3	1050	}
dirkx	0:a259777c45a3	1051	}
dirkx	0:a259777c45a3	1052
dirkx	0:a259777c45a3	1053	/* If the incoming segment contains data, we must process it
dirkx	0:a259777c45a3	1054	further. */
dirkx	0:a259777c45a3	1055	if (tcplen > 0) {
dirkx	0:a259777c45a3	1056	/* This code basically does three things:
dirkx	0:a259777c45a3	1057
dirkx	0:a259777c45a3	1058	+) If the incoming segment contains data that is the next
dirkx	0:a259777c45a3	1059	in-sequence data, this data is passed to the application. This
dirkx	0:a259777c45a3	1060	might involve trimming the first edge of the data. The rcv_nxt
dirkx	0:a259777c45a3	1061	variable and the advertised window are adjusted.
dirkx	0:a259777c45a3	1062
dirkx	0:a259777c45a3	1063	+) If the incoming segment has data that is above the next
dirkx	0:a259777c45a3	1064	sequence number expected (->rcv_nxt), the segment is placed on
dirkx	0:a259777c45a3	1065	the ->ooseq queue. This is done by finding the appropriate
dirkx	0:a259777c45a3	1066	place in the ->ooseq queue (which is ordered by sequence
dirkx	0:a259777c45a3	1067	number) and trim the segment in both ends if needed. An
dirkx	0:a259777c45a3	1068	immediate ACK is sent to indicate that we received an
dirkx	0:a259777c45a3	1069	out-of-sequence segment.
dirkx	0:a259777c45a3	1070
dirkx	0:a259777c45a3	1071	+) Finally, we check if the first segment on the ->ooseq queue
dirkx	0:a259777c45a3	1072	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
dirkx	0:a259777c45a3	1073	rcv_nxt > ooseq->seqno, we must trim the first edge of the
dirkx	0:a259777c45a3	1074	segment on ->ooseq before we adjust rcv_nxt. The data in the
dirkx	0:a259777c45a3	1075	segments that are now on sequence are chained onto the
dirkx	0:a259777c45a3	1076	incoming segment so that we only need to call the application
dirkx	0:a259777c45a3	1077	once.
dirkx	0:a259777c45a3	1078	*/
dirkx	0:a259777c45a3	1079
dirkx	0:a259777c45a3	1080	/* First, we check if we must trim the first edge. We have to do
dirkx	0:a259777c45a3	1081	this if the sequence number of the incoming segment is less
dirkx	0:a259777c45a3	1082	than rcv_nxt, and the sequence number plus the length of the
dirkx	0:a259777c45a3	1083	segment is larger than rcv_nxt. */
dirkx	0:a259777c45a3	1084	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
dirkx	0:a259777c45a3	1085	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
dirkx	0:a259777c45a3	1086	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
dirkx	0:a259777c45a3	1087	/* Trimming the first edge is done by pushing the payload
dirkx	0:a259777c45a3	1088	pointer in the pbuf downwards. This is somewhat tricky since
dirkx	0:a259777c45a3	1089	we do not want to discard the full contents of the pbuf up to
dirkx	0:a259777c45a3	1090	the new starting point of the data since we have to keep the
dirkx	0:a259777c45a3	1091	TCP header which is present in the first pbuf in the chain.
dirkx	0:a259777c45a3	1092
dirkx	0:a259777c45a3	1093	What is done is really quite a nasty hack: the first pbuf in
dirkx	0:a259777c45a3	1094	the pbuf chain is pointed to by inseg.p. Since we need to be
dirkx	0:a259777c45a3	1095	able to deallocate the whole pbuf, we cannot change this
dirkx	0:a259777c45a3	1096	inseg.p pointer to point to any of the later pbufs in the
dirkx	0:a259777c45a3	1097	chain. Instead, we point the ->payload pointer in the first
dirkx	0:a259777c45a3	1098	pbuf to data in one of the later pbufs. We also set the
dirkx	0:a259777c45a3	1099	inseg.data pointer to point to the right place. This way, the
dirkx	0:a259777c45a3	1100	->p pointer will still point to the first pbuf, but the
dirkx	0:a259777c45a3	1101	->p->payload pointer will point to data in another pbuf.
dirkx	0:a259777c45a3	1102
dirkx	0:a259777c45a3	1103	After we are done with adjusting the pbuf pointers we must
dirkx	0:a259777c45a3	1104	adjust the ->data pointer in the seg and the segment
dirkx	0:a259777c45a3	1105	length.*/
dirkx	0:a259777c45a3	1106
dirkx	0:a259777c45a3	1107	off = pcb->rcv_nxt - seqno;
dirkx	0:a259777c45a3	1108	p = inseg.p;
dirkx	0:a259777c45a3	1109	LWIP_ASSERT("inseg.p != NULL", inseg.p);
dirkx	0:a259777c45a3	1110	LWIP_ASSERT("insane offset!", (off < 0x7fff));
dirkx	0:a259777c45a3	1111	if (inseg.p->len < off) {
dirkx	0:a259777c45a3	1112	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
dirkx	0:a259777c45a3	1113	new_tot_len = (u16_t)(inseg.p->tot_len - off);
dirkx	0:a259777c45a3	1114	while (p->len < off) {
dirkx	0:a259777c45a3	1115	off -= p->len;
dirkx	0:a259777c45a3	1116	/* KJM following line changed (with addition of new_tot_len var)
dirkx	0:a259777c45a3	1117	to fix bug #9076
dirkx	0:a259777c45a3	1118	inseg.p->tot_len -= p->len; */
dirkx	0:a259777c45a3	1119	p->tot_len = new_tot_len;
dirkx	0:a259777c45a3	1120	p->len = 0;
dirkx	0:a259777c45a3	1121	p = p->next;
dirkx	0:a259777c45a3	1122	}
dirkx	0:a259777c45a3	1123	if(pbuf_header(p, (s16_t)-off)) {
dirkx	0:a259777c45a3	1124	/* Do we need to cope with this failing? Assert for now */
dirkx	0:a259777c45a3	1125	LWIP_ASSERT("pbuf_header failed", 0);
dirkx	0:a259777c45a3	1126	}
dirkx	0:a259777c45a3	1127	} else {
dirkx	0:a259777c45a3	1128	if(pbuf_header(inseg.p, (s16_t)-off)) {
dirkx	0:a259777c45a3	1129	/* Do we need to cope with this failing? Assert for now */
dirkx	0:a259777c45a3	1130	LWIP_ASSERT("pbuf_header failed", 0);
dirkx	0:a259777c45a3	1131	}
dirkx	0:a259777c45a3	1132	}
dirkx	0:a259777c45a3	1133	/* KJM following line changed to use p->payload rather than inseg->p->payload
dirkx	0:a259777c45a3	1134	to fix bug #9076 */
dirkx	0:a259777c45a3	1135	inseg.dataptr = p->payload;
dirkx	0:a259777c45a3	1136	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
dirkx	0:a259777c45a3	1137	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
dirkx	0:a259777c45a3	1138	}
dirkx	0:a259777c45a3	1139	else {
dirkx	0:a259777c45a3	1140	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
dirkx	0:a259777c45a3	1141	/* the whole segment is < rcv_nxt */
dirkx	0:a259777c45a3	1142	/* must be a duplicate of a packet that has already been correctly handled */
dirkx	0:a259777c45a3	1143
dirkx	0:a259777c45a3	1144	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
dirkx	0:a259777c45a3	1145	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	1146	}
dirkx	0:a259777c45a3	1147	}
dirkx	0:a259777c45a3	1148
dirkx	0:a259777c45a3	1149	/* The sequence number must be within the window (above rcv_nxt
dirkx	0:a259777c45a3	1150	and below rcv_nxt + rcv_wnd) in order to be further
dirkx	0:a259777c45a3	1151	processed. */
dirkx	0:a259777c45a3	1152	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
dirkx	0:a259777c45a3	1153	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
dirkx	0:a259777c45a3	1154	if (pcb->rcv_nxt == seqno) {
dirkx	0:a259777c45a3	1155	/* The incoming segment is the next in sequence. We check if
dirkx	0:a259777c45a3	1156	we have to trim the end of the segment and update rcv_nxt
dirkx	0:a259777c45a3	1157	and pass the data to the application. */
dirkx	0:a259777c45a3	1158	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:a259777c45a3	1159
dirkx	0:a259777c45a3	1160	if (tcplen > pcb->rcv_wnd) {
dirkx	0:a259777c45a3	1161	LWIP_DEBUGF(TCP_INPUT_DEBUG,
dirkx	0:a259777c45a3	1162	("tcp_receive: other end overran receive window"
dirkx	0:a259777c45a3	1163	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
dirkx	0:a259777c45a3	1164	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
dirkx	0:a259777c45a3	1165	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	1166	/* Must remove the FIN from the header as we're trimming
dirkx	0:a259777c45a3	1167	* that byte of sequence-space from the packet */
dirkx	0:a259777c45a3	1168	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
dirkx	0:a259777c45a3	1169	}
dirkx	0:a259777c45a3	1170	/* Adjust length of segment to fit in the window. */
dirkx	0:a259777c45a3	1171	inseg.len = pcb->rcv_wnd;
dirkx	0:a259777c45a3	1172	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
dirkx	0:a259777c45a3	1173	inseg.len -= 1;
dirkx	0:a259777c45a3	1174	}
dirkx	0:a259777c45a3	1175	pbuf_realloc(inseg.p, inseg.len);
dirkx	0:a259777c45a3	1176	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:a259777c45a3	1177	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
dirkx	0:a259777c45a3	1178	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
dirkx	0:a259777c45a3	1179	}
dirkx	0:a259777c45a3	1180	#if TCP_QUEUE_OOSEQ
dirkx	0:a259777c45a3	1181	/* Received in-sequence data, adjust ooseq data if:
dirkx	0:a259777c45a3	1182	- FIN has been received or
dirkx	0:a259777c45a3	1183	- inseq overlaps with ooseq */
dirkx	0:a259777c45a3	1184	if (pcb->ooseq != NULL) {
dirkx	0:a259777c45a3	1185	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	1186	LWIP_DEBUGF(TCP_INPUT_DEBUG,
dirkx	0:a259777c45a3	1187	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
dirkx	0:a259777c45a3	1188	/* Received in-order FIN means anything that was received
dirkx	0:a259777c45a3	1189	* out of order must now have been received in-order, so
dirkx	0:a259777c45a3	1190	* bin the ooseq queue */
dirkx	0:a259777c45a3	1191	while (pcb->ooseq != NULL) {
dirkx	0:a259777c45a3	1192	struct tcp_seg *old_ooseq = pcb->ooseq;
dirkx	0:a259777c45a3	1193	pcb->ooseq = pcb->ooseq->next;
dirkx	0:a259777c45a3	1194	tcp_seg_free(old_ooseq);
dirkx	0:a259777c45a3	1195	}
dirkx	0:a259777c45a3	1196	}
dirkx	0:a259777c45a3	1197	else {
dirkx	0:a259777c45a3	1198	next = pcb->ooseq;
dirkx	0:a259777c45a3	1199	/* Remove all segments on ooseq that are covered by inseg already.
dirkx	0:a259777c45a3	1200	* FIN is copied from ooseq to inseg if present. */
dirkx	0:a259777c45a3	1201	while (next &&
dirkx	0:a259777c45a3	1202	TCP_SEQ_GEQ(seqno + tcplen,
dirkx	0:a259777c45a3	1203	next->tcphdr->seqno + next->len)) {
dirkx	0:a259777c45a3	1204	/* inseg cannot have FIN here (already processed above) */
dirkx	0:a259777c45a3	1205	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
dirkx	0:a259777c45a3	1206	(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
dirkx	0:a259777c45a3	1207	TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
dirkx	0:a259777c45a3	1208	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:a259777c45a3	1209	}
dirkx	0:a259777c45a3	1210	prev = next;
dirkx	0:a259777c45a3	1211	next = next->next;
dirkx	0:a259777c45a3	1212	tcp_seg_free(prev);
dirkx	0:a259777c45a3	1213	}
dirkx	0:a259777c45a3	1214	/* Now trim right side of inseg if it overlaps with the first
dirkx	0:a259777c45a3	1215	* segment on ooseq */
dirkx	0:a259777c45a3	1216	if (next &&
dirkx	0:a259777c45a3	1217	TCP_SEQ_GT(seqno + tcplen,
dirkx	0:a259777c45a3	1218	next->tcphdr->seqno)) {
dirkx	0:a259777c45a3	1219	/* inseg cannot have FIN here (already processed above) */
dirkx	0:a259777c45a3	1220	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
dirkx	0:a259777c45a3	1221	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
dirkx	0:a259777c45a3	1222	inseg.len -= 1;
dirkx	0:a259777c45a3	1223	}
dirkx	0:a259777c45a3	1224	pbuf_realloc(inseg.p, inseg.len);
dirkx	0:a259777c45a3	1225	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:a259777c45a3	1226	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
dirkx	0:a259777c45a3	1227	(seqno + tcplen) == next->tcphdr->seqno);
dirkx	0:a259777c45a3	1228	}
dirkx	0:a259777c45a3	1229	pcb->ooseq = next;
dirkx	0:a259777c45a3	1230	}
dirkx	0:a259777c45a3	1231	}
dirkx	0:a259777c45a3	1232	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:a259777c45a3	1233
dirkx	0:a259777c45a3	1234	pcb->rcv_nxt = seqno + tcplen;
dirkx	0:a259777c45a3	1235
dirkx	0:a259777c45a3	1236	/* Update the receiver's (our) window. */
dirkx	0:a259777c45a3	1237	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
dirkx	0:a259777c45a3	1238	pcb->rcv_wnd -= tcplen;
dirkx	0:a259777c45a3	1239
dirkx	0:a259777c45a3	1240	tcp_update_rcv_ann_wnd(pcb);
dirkx	0:a259777c45a3	1241
dirkx	0:a259777c45a3	1242	/* If there is data in the segment, we make preparations to
dirkx	0:a259777c45a3	1243	pass this up to the application. The ->recv_data variable
dirkx	0:a259777c45a3	1244	is used for holding the pbuf that goes to the
dirkx	0:a259777c45a3	1245	application. The code for reassembling out-of-sequence data
dirkx	0:a259777c45a3	1246	chains its data on this pbuf as well.
dirkx	0:a259777c45a3	1247
dirkx	0:a259777c45a3	1248	If the segment was a FIN, we set the TF_GOT_FIN flag that will
dirkx	0:a259777c45a3	1249	be used to indicate to the application that the remote side has
dirkx	0:a259777c45a3	1250	closed its end of the connection. */
dirkx	0:a259777c45a3	1251	if (inseg.p->tot_len > 0) {
dirkx	0:a259777c45a3	1252	recv_data = inseg.p;
dirkx	0:a259777c45a3	1253	/* Since this pbuf now is the responsibility of the
dirkx	0:a259777c45a3	1254	application, we delete our reference to it so that we won't
dirkx	0:a259777c45a3	1255	(mistakingly) deallocate it. */
dirkx	0:a259777c45a3	1256	inseg.p = NULL;
dirkx	0:a259777c45a3	1257	}
dirkx	0:a259777c45a3	1258	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	1259	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
dirkx	0:a259777c45a3	1260	recv_flags \|= TF_GOT_FIN;
dirkx	0:a259777c45a3	1261	}
dirkx	0:a259777c45a3	1262
dirkx	0:a259777c45a3	1263	#if TCP_QUEUE_OOSEQ
dirkx	0:a259777c45a3	1264	/* We now check if we have segments on the ->ooseq queue that
dirkx	0:a259777c45a3	1265	are now in sequence. */
dirkx	0:a259777c45a3	1266	while (pcb->ooseq != NULL &&
dirkx	0:a259777c45a3	1267	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
dirkx	0:a259777c45a3	1268
dirkx	0:a259777c45a3	1269	cseg = pcb->ooseq;
dirkx	0:a259777c45a3	1270	seqno = pcb->ooseq->tcphdr->seqno;
dirkx	0:a259777c45a3	1271
dirkx	0:a259777c45a3	1272	pcb->rcv_nxt += TCP_TCPLEN(cseg);
dirkx	0:a259777c45a3	1273	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
dirkx	0:a259777c45a3	1274	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
dirkx	0:a259777c45a3	1275	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
dirkx	0:a259777c45a3	1276
dirkx	0:a259777c45a3	1277	tcp_update_rcv_ann_wnd(pcb);
dirkx	0:a259777c45a3	1278
dirkx	0:a259777c45a3	1279	if (cseg->p->tot_len > 0) {
dirkx	0:a259777c45a3	1280	/* Chain this pbuf onto the pbuf that we will pass to
dirkx	0:a259777c45a3	1281	the application. */
dirkx	0:a259777c45a3	1282	if (recv_data) {
dirkx	0:a259777c45a3	1283	pbuf_cat(recv_data, cseg->p);
dirkx	0:a259777c45a3	1284	} else {
dirkx	0:a259777c45a3	1285	recv_data = cseg->p;
dirkx	0:a259777c45a3	1286	}
dirkx	0:a259777c45a3	1287	cseg->p = NULL;
dirkx	0:a259777c45a3	1288	}
dirkx	0:a259777c45a3	1289	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	1290	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
dirkx	0:a259777c45a3	1291	recv_flags \|= TF_GOT_FIN;
dirkx	0:a259777c45a3	1292	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
dirkx	0:a259777c45a3	1293	pcb->state = CLOSE_WAIT;
dirkx	0:a259777c45a3	1294	}
dirkx	0:a259777c45a3	1295	}
dirkx	0:a259777c45a3	1296
dirkx	0:a259777c45a3	1297	pcb->ooseq = cseg->next;
dirkx	0:a259777c45a3	1298	tcp_seg_free(cseg);
dirkx	0:a259777c45a3	1299	}
dirkx	0:a259777c45a3	1300	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:a259777c45a3	1301
dirkx	0:a259777c45a3	1302
dirkx	0:a259777c45a3	1303	/* Acknowledge the segment(s). */
dirkx	0:a259777c45a3	1304	tcp_ack(pcb);
dirkx	0:a259777c45a3	1305
dirkx	0:a259777c45a3	1306	} else {
dirkx	0:a259777c45a3	1307	/* We get here if the incoming segment is out-of-sequence. */
dirkx	0:a259777c45a3	1308	tcp_send_empty_ack(pcb);
dirkx	0:a259777c45a3	1309	#if TCP_QUEUE_OOSEQ
dirkx	0:a259777c45a3	1310	/* We queue the segment on the ->ooseq queue. */
dirkx	0:a259777c45a3	1311	if (pcb->ooseq == NULL) {
dirkx	0:a259777c45a3	1312	pcb->ooseq = tcp_seg_copy(&inseg);
dirkx	0:a259777c45a3	1313	} else {
dirkx	0:a259777c45a3	1314	/* If the queue is not empty, we walk through the queue and
dirkx	0:a259777c45a3	1315	try to find a place where the sequence number of the
dirkx	0:a259777c45a3	1316	incoming segment is between the sequence numbers of the
dirkx	0:a259777c45a3	1317	previous and the next segment on the ->ooseq queue. That is
dirkx	0:a259777c45a3	1318	the place where we put the incoming segment. If needed, we
dirkx	0:a259777c45a3	1319	trim the second edges of the previous and the incoming
dirkx	0:a259777c45a3	1320	segment so that it will fit into the sequence.
dirkx	0:a259777c45a3	1321
dirkx	0:a259777c45a3	1322	If the incoming segment has the same sequence number as a
dirkx	0:a259777c45a3	1323	segment on the ->ooseq queue, we discard the segment that
dirkx	0:a259777c45a3	1324	contains less data. */
dirkx	0:a259777c45a3	1325
dirkx	0:a259777c45a3	1326	prev = NULL;
dirkx	0:a259777c45a3	1327	for(next = pcb->ooseq; next != NULL; next = next->next) {
dirkx	0:a259777c45a3	1328	if (seqno == next->tcphdr->seqno) {
dirkx	0:a259777c45a3	1329	/* The sequence number of the incoming segment is the
dirkx	0:a259777c45a3	1330	same as the sequence number of the segment on
dirkx	0:a259777c45a3	1331	->ooseq. We check the lengths to see which one to
dirkx	0:a259777c45a3	1332	discard. */
dirkx	0:a259777c45a3	1333	if (inseg.len > next->len) {
dirkx	0:a259777c45a3	1334	/* The incoming segment is larger than the old
dirkx	0:a259777c45a3	1335	segment. We replace some segments with the new
dirkx	0:a259777c45a3	1336	one. */
dirkx	0:a259777c45a3	1337	cseg = tcp_seg_copy(&inseg);
dirkx	0:a259777c45a3	1338	if (cseg != NULL) {
dirkx	0:a259777c45a3	1339	if (prev != NULL) {
dirkx	0:a259777c45a3	1340	prev->next = cseg;
dirkx	0:a259777c45a3	1341	} else {
dirkx	0:a259777c45a3	1342	pcb->ooseq = cseg;
dirkx	0:a259777c45a3	1343	}
dirkx	0:a259777c45a3	1344	tcp_oos_insert_segment(cseg, next);
dirkx	0:a259777c45a3	1345	}
dirkx	0:a259777c45a3	1346	break;
dirkx	0:a259777c45a3	1347	} else {
dirkx	0:a259777c45a3	1348	/* Either the lenghts are the same or the incoming
dirkx	0:a259777c45a3	1349	segment was smaller than the old one; in either
dirkx	0:a259777c45a3	1350	case, we ditch the incoming segment. */
dirkx	0:a259777c45a3	1351	break;
dirkx	0:a259777c45a3	1352	}
dirkx	0:a259777c45a3	1353	} else {
dirkx	0:a259777c45a3	1354	if (prev == NULL) {
dirkx	0:a259777c45a3	1355	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
dirkx	0:a259777c45a3	1356	/* The sequence number of the incoming segment is lower
dirkx	0:a259777c45a3	1357	than the sequence number of the first segment on the
dirkx	0:a259777c45a3	1358	queue. We put the incoming segment first on the
dirkx	0:a259777c45a3	1359	queue. */
dirkx	0:a259777c45a3	1360	cseg = tcp_seg_copy(&inseg);
dirkx	0:a259777c45a3	1361	if (cseg != NULL) {
dirkx	0:a259777c45a3	1362	pcb->ooseq = cseg;
dirkx	0:a259777c45a3	1363	tcp_oos_insert_segment(cseg, next);
dirkx	0:a259777c45a3	1364	}
dirkx	0:a259777c45a3	1365	break;
dirkx	0:a259777c45a3	1366	}
dirkx	0:a259777c45a3	1367	} else {
dirkx	0:a259777c45a3	1368	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
dirkx	0:a259777c45a3	1369	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
dirkx	0:a259777c45a3	1370	if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
dirkx	0:a259777c45a3	1371	/* The sequence number of the incoming segment is in
dirkx	0:a259777c45a3	1372	between the sequence numbers of the previous and
dirkx	0:a259777c45a3	1373	the next segment on ->ooseq. We trim trim the previous
dirkx	0:a259777c45a3	1374	segment, delete next segments that included in received segment
dirkx	0:a259777c45a3	1375	and trim received, if needed. */
dirkx	0:a259777c45a3	1376	cseg = tcp_seg_copy(&inseg);
dirkx	0:a259777c45a3	1377	if (cseg != NULL) {
dirkx	0:a259777c45a3	1378	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
dirkx	0:a259777c45a3	1379	/* We need to trim the prev segment. */
dirkx	0:a259777c45a3	1380	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
dirkx	0:a259777c45a3	1381	pbuf_realloc(prev->p, prev->len);
dirkx	0:a259777c45a3	1382	}
dirkx	0:a259777c45a3	1383	prev->next = cseg;
dirkx	0:a259777c45a3	1384	tcp_oos_insert_segment(cseg, next);
dirkx	0:a259777c45a3	1385	}
dirkx	0:a259777c45a3	1386	break;
dirkx	0:a259777c45a3	1387	}
dirkx	0:a259777c45a3	1388	}
dirkx	0:a259777c45a3	1389	/* If the "next" segment is the last segment on the
dirkx	0:a259777c45a3	1390	ooseq queue, we add the incoming segment to the end
dirkx	0:a259777c45a3	1391	of the list. */
dirkx	0:a259777c45a3	1392	if (next->next == NULL &&
dirkx	0:a259777c45a3	1393	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
dirkx	0:a259777c45a3	1394	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
dirkx	0:a259777c45a3	1395	/* segment "next" already contains all data */
dirkx	0:a259777c45a3	1396	break;
dirkx	0:a259777c45a3	1397	}
dirkx	0:a259777c45a3	1398	next->next = tcp_seg_copy(&inseg);
dirkx	0:a259777c45a3	1399	if (next->next != NULL) {
dirkx	0:a259777c45a3	1400	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
dirkx	0:a259777c45a3	1401	/* We need to trim the last segment. */
dirkx	0:a259777c45a3	1402	next->len = (u16_t)(seqno - next->tcphdr->seqno);
dirkx	0:a259777c45a3	1403	pbuf_realloc(next->p, next->len);
dirkx	0:a259777c45a3	1404	}
dirkx	0:a259777c45a3	1405	}
dirkx	0:a259777c45a3	1406	break;
dirkx	0:a259777c45a3	1407	}
dirkx	0:a259777c45a3	1408	}
dirkx	0:a259777c45a3	1409	prev = next;
dirkx	0:a259777c45a3	1410	}
dirkx	0:a259777c45a3	1411	}
dirkx	0:a259777c45a3	1412	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:a259777c45a3	1413
dirkx	0:a259777c45a3	1414	}
dirkx	0:a259777c45a3	1415	} else {
dirkx	0:a259777c45a3	1416	/* The incoming segment is not withing the window. */
dirkx	0:a259777c45a3	1417	tcp_send_empty_ack(pcb);
dirkx	0:a259777c45a3	1418	}
dirkx	0:a259777c45a3	1419	} else {
dirkx	0:a259777c45a3	1420	/* Segments with length 0 is taken care of here. Segments that
dirkx	0:a259777c45a3	1421	fall out of the window are ACKed. */
dirkx	0:a259777c45a3	1422	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
dirkx	0:a259777c45a3	1423	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
dirkx	0:a259777c45a3	1424	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
dirkx	0:a259777c45a3	1425	tcp_ack_now(pcb);
dirkx	0:a259777c45a3	1426	}
dirkx	0:a259777c45a3	1427	}
dirkx	0:a259777c45a3	1428	}
dirkx	0:a259777c45a3	1429
dirkx	0:a259777c45a3	1430	/**
dirkx	0:a259777c45a3	1431	* Parses the options contained in the incoming segment.
dirkx	0:a259777c45a3	1432	*
dirkx	0:a259777c45a3	1433	* Called from tcp_listen_input() and tcp_process().
dirkx	0:a259777c45a3	1434	* Currently, only the MSS option is supported!
dirkx	0:a259777c45a3	1435	*
dirkx	0:a259777c45a3	1436	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:a259777c45a3	1437	*/
dirkx	0:a259777c45a3	1438	static void
dirkx	0:a259777c45a3	1439	tcp_parseopt(struct tcp_pcb *pcb)
dirkx	0:a259777c45a3	1440	{
dirkx	0:a259777c45a3	1441	u16_t c, max_c;
dirkx	0:a259777c45a3	1442	u16_t mss;
dirkx	0:a259777c45a3	1443	u8_t *opts, opt;
dirkx	0:a259777c45a3	1444	#if LWIP_TCP_TIMESTAMPS
dirkx	0:a259777c45a3	1445	u32_t tsval;
dirkx	0:a259777c45a3	1446	#endif
dirkx	0:a259777c45a3	1447
dirkx	0:a259777c45a3	1448	opts = (u8_t *)tcphdr + TCP_HLEN;
dirkx	0:a259777c45a3	1449
dirkx	0:a259777c45a3	1450	/* Parse the TCP MSS option, if present. */
dirkx	0:a259777c45a3	1451	if(TCPH_HDRLEN(tcphdr) > 0x5) {
dirkx	0:a259777c45a3	1452	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
dirkx	0:a259777c45a3	1453	for (c = 0; c < max_c; ) {
dirkx	0:a259777c45a3	1454	opt = opts[c];
dirkx	0:a259777c45a3	1455	switch (opt) {
dirkx	0:a259777c45a3	1456	case 0x00:
dirkx	0:a259777c45a3	1457	/* End of options. */
dirkx	0:a259777c45a3	1458	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
dirkx	0:a259777c45a3	1459	return;
dirkx	0:a259777c45a3	1460	case 0x01:
dirkx	0:a259777c45a3	1461	/* NOP option. */
dirkx	0:a259777c45a3	1462	++c;
dirkx	0:a259777c45a3	1463	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
dirkx	0:a259777c45a3	1464	break;
dirkx	0:a259777c45a3	1465	case 0x02:
dirkx	0:a259777c45a3	1466	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
dirkx	0:a259777c45a3	1467	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
dirkx	0:a259777c45a3	1468	/* Bad length */
dirkx	0:a259777c45a3	1469	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:a259777c45a3	1470	return;
dirkx	0:a259777c45a3	1471	}
dirkx	0:a259777c45a3	1472	/* An MSS option with the right option length. */
dirkx	0:a259777c45a3	1473	mss = (opts[c + 2] << 8) \| opts[c + 3];
dirkx	0:a259777c45a3	1474	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
dirkx	0:a259777c45a3	1475	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
dirkx	0:a259777c45a3	1476	/* Advance to next option */
dirkx	0:a259777c45a3	1477	c += 0x04;
dirkx	0:a259777c45a3	1478	break;
dirkx	0:a259777c45a3	1479	#if LWIP_TCP_TIMESTAMPS
dirkx	0:a259777c45a3	1480	case 0x08:
dirkx	0:a259777c45a3	1481	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
dirkx	0:a259777c45a3	1482	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
dirkx	0:a259777c45a3	1483	/* Bad length */
dirkx	0:a259777c45a3	1484	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:a259777c45a3	1485	return;
dirkx	0:a259777c45a3	1486	}
dirkx	0:a259777c45a3	1487	/* TCP timestamp option with valid length */
dirkx	0:a259777c45a3	1488	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
dirkx	0:a259777c45a3	1489	(opts[c+4] << 16) \| (opts[c+5] << 24);
dirkx	0:a259777c45a3	1490	if (flags & TCP_SYN) {
dirkx	0:a259777c45a3	1491	pcb->ts_recent = ntohl(tsval);
dirkx	0:a259777c45a3	1492	pcb->flags \|= TF_TIMESTAMP;
dirkx	0:a259777c45a3	1493	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
dirkx	0:a259777c45a3	1494	pcb->ts_recent = ntohl(tsval);
dirkx	0:a259777c45a3	1495	}
dirkx	0:a259777c45a3	1496	/* Advance to next option */
dirkx	0:a259777c45a3	1497	c += 0x0A;
dirkx	0:a259777c45a3	1498	break;
dirkx	0:a259777c45a3	1499	#endif
dirkx	0:a259777c45a3	1500	default:
dirkx	0:a259777c45a3	1501	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
dirkx	0:a259777c45a3	1502	if (opts[c + 1] == 0) {
dirkx	0:a259777c45a3	1503	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:a259777c45a3	1504	/* If the length field is zero, the options are malformed
dirkx	0:a259777c45a3	1505	and we don't process them further. */
dirkx	0:a259777c45a3	1506	return;
dirkx	0:a259777c45a3	1507	}
dirkx	0:a259777c45a3	1508	/* All other options have a length field, so that we easily
dirkx	0:a259777c45a3	1509	can skip past them. */
dirkx	0:a259777c45a3	1510	c += opts[c + 1];
dirkx	0:a259777c45a3	1511	}
dirkx	0:a259777c45a3	1512	}
dirkx	0:a259777c45a3	1513	}
dirkx	0:a259777c45a3	1514	}
dirkx	0:a259777c45a3	1515
dirkx	0:a259777c45a3	1516	#endif /* LWIP_TCP */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	14 Aug 2010
Imports:	49
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	1

lwip/core/tcp_in.c@0:a259777c45a3, 2010-08-14 (annotated)

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