Bonjour - Bonjour/Zerconf library

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

Bonjour/Zerconf library

lwip/core/tcp_in.c@5:8e53abda9900, 2010-08-14 (annotated)

Committer:: dirkx
Date:: Sat Aug 14 15:54:31 2010 +0000
Revision:: 5:8e53abda9900
Parent:: 0:355018f44c9f

Who changed what in which revision?

User	Revision	Line number	New contents of line
dirkx	0:355018f44c9f	1	/**
dirkx	0:355018f44c9f	2	* @file
dirkx	0:355018f44c9f	3	* Transmission Control Protocol, incoming traffic
dirkx	0:355018f44c9f	4	*
dirkx	0:355018f44c9f	5	* The input processing functions of the TCP layer.
dirkx	0:355018f44c9f	6	*
dirkx	0:355018f44c9f	7	* These functions are generally called in the order (ip_input() ->)
dirkx	0:355018f44c9f	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
dirkx	0:355018f44c9f	9	*
dirkx	0:355018f44c9f	10	*/
dirkx	0:355018f44c9f	11
dirkx	0:355018f44c9f	12	/*
dirkx	0:355018f44c9f	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
dirkx	0:355018f44c9f	14	* All rights reserved.
dirkx	0:355018f44c9f	15	*
dirkx	0:355018f44c9f	16	* Redistribution and use in source and binary forms, with or without modification,
dirkx	0:355018f44c9f	17	* are permitted provided that the following conditions are met:
dirkx	0:355018f44c9f	18	*
dirkx	0:355018f44c9f	19	* 1. Redistributions of source code must retain the above copyright notice,
dirkx	0:355018f44c9f	20	* this list of conditions and the following disclaimer.
dirkx	0:355018f44c9f	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
dirkx	0:355018f44c9f	22	* this list of conditions and the following disclaimer in the documentation
dirkx	0:355018f44c9f	23	* and/or other materials provided with the distribution.
dirkx	0:355018f44c9f	24	* 3. The name of the author may not be used to endorse or promote products
dirkx	0:355018f44c9f	25	* derived from this software without specific prior written permission.
dirkx	0:355018f44c9f	26	*
dirkx	0:355018f44c9f	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
dirkx	0:355018f44c9f	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
dirkx	0:355018f44c9f	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
dirkx	0:355018f44c9f	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
dirkx	0:355018f44c9f	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
dirkx	0:355018f44c9f	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
dirkx	0:355018f44c9f	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
dirkx	0:355018f44c9f	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
dirkx	0:355018f44c9f	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
dirkx	0:355018f44c9f	36	* OF SUCH DAMAGE.
dirkx	0:355018f44c9f	37	*
dirkx	0:355018f44c9f	38	* This file is part of the lwIP TCP/IP stack.
dirkx	0:355018f44c9f	39	*
dirkx	0:355018f44c9f	40	* Author: Adam Dunkels <adam@sics.se>
dirkx	0:355018f44c9f	41	*
dirkx	0:355018f44c9f	42	*/
dirkx	0:355018f44c9f	43
dirkx	0:355018f44c9f	44	#include "lwip/opt.h"
dirkx	0:355018f44c9f	45
dirkx	0:355018f44c9f	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
dirkx	0:355018f44c9f	47
dirkx	0:355018f44c9f	48	#include "lwip/tcp_impl.h"
dirkx	0:355018f44c9f	49	#include "lwip/def.h"
dirkx	0:355018f44c9f	50	#include "lwip/ip_addr.h"
dirkx	0:355018f44c9f	51	#include "lwip/netif.h"
dirkx	0:355018f44c9f	52	#include "lwip/mem.h"
dirkx	0:355018f44c9f	53	#include "lwip/memp.h"
dirkx	0:355018f44c9f	54	#include "lwip/inet_chksum.h"
dirkx	0:355018f44c9f	55	#include "lwip/stats.h"
dirkx	0:355018f44c9f	56	#include "lwip/snmp.h"
dirkx	0:355018f44c9f	57	#include "arch/perf.h"
dirkx	0:355018f44c9f	58
dirkx	0:355018f44c9f	59	/* These variables are global to all functions involved in the input
dirkx	0:355018f44c9f	60	processing of TCP segments. They are set by the tcp_input()
dirkx	0:355018f44c9f	61	function. */
dirkx	0:355018f44c9f	62	static struct tcp_seg inseg;
dirkx	0:355018f44c9f	63	static struct tcp_hdr *tcphdr;
dirkx	0:355018f44c9f	64	static struct ip_hdr *iphdr;
dirkx	0:355018f44c9f	65	static u32_t seqno, ackno;
dirkx	0:355018f44c9f	66	static u8_t flags;
dirkx	0:355018f44c9f	67	static u16_t tcplen;
dirkx	0:355018f44c9f	68
dirkx	0:355018f44c9f	69	static u8_t recv_flags;
dirkx	0:355018f44c9f	70	static struct pbuf *recv_data;
dirkx	0:355018f44c9f	71
dirkx	0:355018f44c9f	72	struct tcp_pcb *tcp_input_pcb;
dirkx	0:355018f44c9f	73
dirkx	0:355018f44c9f	74	/* Forward declarations. */
dirkx	0:355018f44c9f	75	static err_t tcp_process(struct tcp_pcb *pcb);
dirkx	0:355018f44c9f	76	static void tcp_receive(struct tcp_pcb *pcb);
dirkx	0:355018f44c9f	77	static void tcp_parseopt(struct tcp_pcb *pcb);
dirkx	0:355018f44c9f	78
dirkx	0:355018f44c9f	79	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
dirkx	0:355018f44c9f	80	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
dirkx	0:355018f44c9f	81
dirkx	0:355018f44c9f	82	/**
dirkx	0:355018f44c9f	83	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
dirkx	0:355018f44c9f	84	* the segment between the PCBs and passes it on to tcp_process(), which implements
dirkx	0:355018f44c9f	85	* the TCP finite state machine. This function is called by the IP layer (in
dirkx	0:355018f44c9f	86	* ip_input()).
dirkx	0:355018f44c9f	87	*
dirkx	0:355018f44c9f	88	* @param p received TCP segment to process (p->payload pointing to the IP header)
dirkx	0:355018f44c9f	89	* @param inp network interface on which this segment was received
dirkx	0:355018f44c9f	90	*/
dirkx	0:355018f44c9f	91	void
dirkx	0:355018f44c9f	92	tcp_input(struct pbuf p, struct netif inp)
dirkx	0:355018f44c9f	93	{
dirkx	0:355018f44c9f	94	struct tcp_pcb pcb, prev;
dirkx	0:355018f44c9f	95	struct tcp_pcb_listen *lpcb;
dirkx	0:355018f44c9f	96	u8_t hdrlen;
dirkx	0:355018f44c9f	97	err_t err;
dirkx	0:355018f44c9f	98
dirkx	0:355018f44c9f	99	PERF_START;
dirkx	0:355018f44c9f	100
dirkx	0:355018f44c9f	101	TCP_STATS_INC(tcp.recv);
dirkx	0:355018f44c9f	102	snmp_inc_tcpinsegs();
dirkx	0:355018f44c9f	103
dirkx	0:355018f44c9f	104	iphdr = (struct ip_hdr *)p->payload;
dirkx	0:355018f44c9f	105	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
dirkx	0:355018f44c9f	106
dirkx	0:355018f44c9f	107	#if TCP_INPUT_DEBUG
dirkx	0:355018f44c9f	108	tcp_debug_print(tcphdr);
dirkx	0:355018f44c9f	109	#endif
dirkx	0:355018f44c9f	110
dirkx	0:355018f44c9f	111	/* remove header from payload */
dirkx	0:355018f44c9f	112	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
dirkx	0:355018f44c9f	113	/* drop short packets */
dirkx	0:355018f44c9f	114	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
dirkx	0:355018f44c9f	115	TCP_STATS_INC(tcp.lenerr);
dirkx	0:355018f44c9f	116	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	117	snmp_inc_tcpinerrs();
dirkx	0:355018f44c9f	118	pbuf_free(p);
dirkx	0:355018f44c9f	119	return;
dirkx	0:355018f44c9f	120	}
dirkx	0:355018f44c9f	121
dirkx	0:355018f44c9f	122	/* Don't even process incoming broadcasts/multicasts. */
dirkx	0:355018f44c9f	123	if (ip_addr_isbroadcast(&(iphdr->dest), inp) \|\|
dirkx	0:355018f44c9f	124	ip_addr_ismulticast(&(iphdr->dest))) {
dirkx	0:355018f44c9f	125	TCP_STATS_INC(tcp.proterr);
dirkx	0:355018f44c9f	126	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	127	snmp_inc_tcpinerrs();
dirkx	0:355018f44c9f	128	pbuf_free(p);
dirkx	0:355018f44c9f	129	return;
dirkx	0:355018f44c9f	130	}
dirkx	0:355018f44c9f	131
dirkx	0:355018f44c9f	132	#if CHECKSUM_CHECK_TCP
dirkx	0:355018f44c9f	133	/* Verify TCP checksum. */
dirkx	0:355018f44c9f	134	if (inet_chksum_pseudo(p, &iphdr->src, &iphdr->dest,
dirkx	0:355018f44c9f	135	IP_PROTO_TCP, p->tot_len) != 0) {
dirkx	0:355018f44c9f	136	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
dirkx	0:355018f44c9f	137	inet_chksum_pseudo(p, &iphdr->src, &iphdr->dest,
dirkx	0:355018f44c9f	138	IP_PROTO_TCP, p->tot_len)));
dirkx	0:355018f44c9f	139	#if TCP_DEBUG
dirkx	0:355018f44c9f	140	tcp_debug_print(tcphdr);
dirkx	0:355018f44c9f	141	#endif /* TCP_DEBUG */
dirkx	0:355018f44c9f	142	TCP_STATS_INC(tcp.chkerr);
dirkx	0:355018f44c9f	143	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	144	snmp_inc_tcpinerrs();
dirkx	0:355018f44c9f	145	pbuf_free(p);
dirkx	0:355018f44c9f	146	return;
dirkx	0:355018f44c9f	147	}
dirkx	0:355018f44c9f	148	#endif
dirkx	0:355018f44c9f	149
dirkx	0:355018f44c9f	150	/* Move the payload pointer in the pbuf so that it points to the
dirkx	0:355018f44c9f	151	TCP data instead of the TCP header. */
dirkx	0:355018f44c9f	152	hdrlen = TCPH_HDRLEN(tcphdr);
dirkx	0:355018f44c9f	153	if(pbuf_header(p, -(hdrlen * 4))){
dirkx	0:355018f44c9f	154	/* drop short packets */
dirkx	0:355018f44c9f	155	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
dirkx	0:355018f44c9f	156	TCP_STATS_INC(tcp.lenerr);
dirkx	0:355018f44c9f	157	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	158	snmp_inc_tcpinerrs();
dirkx	0:355018f44c9f	159	pbuf_free(p);
dirkx	0:355018f44c9f	160	return;
dirkx	0:355018f44c9f	161	}
dirkx	0:355018f44c9f	162
dirkx	0:355018f44c9f	163	/* Convert fields in TCP header to host byte order. */
dirkx	0:355018f44c9f	164	tcphdr->src = ntohs(tcphdr->src);
dirkx	0:355018f44c9f	165	tcphdr->dest = ntohs(tcphdr->dest);
dirkx	0:355018f44c9f	166	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
dirkx	0:355018f44c9f	167	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
dirkx	0:355018f44c9f	168	tcphdr->wnd = ntohs(tcphdr->wnd);
dirkx	0:355018f44c9f	169
dirkx	0:355018f44c9f	170	flags = TCPH_FLAGS(tcphdr);
dirkx	0:355018f44c9f	171	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
dirkx	0:355018f44c9f	172
dirkx	0:355018f44c9f	173	/* Demultiplex an incoming segment. First, we check if it is destined
dirkx	0:355018f44c9f	174	for an active connection. */
dirkx	0:355018f44c9f	175	prev = NULL;
dirkx	0:355018f44c9f	176
dirkx	0:355018f44c9f	177
dirkx	0:355018f44c9f	178	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
dirkx	0:355018f44c9f	179	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
dirkx	0:355018f44c9f	180	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
dirkx	0:355018f44c9f	181	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
dirkx	0:355018f44c9f	182	if (pcb->remote_port == tcphdr->src &&
dirkx	0:355018f44c9f	183	pcb->local_port == tcphdr->dest &&
dirkx	0:355018f44c9f	184	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
dirkx	0:355018f44c9f	185	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
dirkx	0:355018f44c9f	186
dirkx	0:355018f44c9f	187	/* Move this PCB to the front of the list so that subsequent
dirkx	0:355018f44c9f	188	lookups will be faster (we exploit locality in TCP segment
dirkx	0:355018f44c9f	189	arrivals). */
dirkx	0:355018f44c9f	190	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
dirkx	0:355018f44c9f	191	if (prev != NULL) {
dirkx	0:355018f44c9f	192	prev->next = pcb->next;
dirkx	0:355018f44c9f	193	pcb->next = tcp_active_pcbs;
dirkx	0:355018f44c9f	194	tcp_active_pcbs = pcb;
dirkx	0:355018f44c9f	195	}
dirkx	0:355018f44c9f	196	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
dirkx	0:355018f44c9f	197	break;
dirkx	0:355018f44c9f	198	}
dirkx	0:355018f44c9f	199	prev = pcb;
dirkx	0:355018f44c9f	200	}
dirkx	0:355018f44c9f	201
dirkx	0:355018f44c9f	202	if (pcb == NULL) {
dirkx	0:355018f44c9f	203	/* If it did not go to an active connection, we check the connections
dirkx	0:355018f44c9f	204	in the TIME-WAIT state. */
dirkx	0:355018f44c9f	205	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
dirkx	0:355018f44c9f	206	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
dirkx	0:355018f44c9f	207	if (pcb->remote_port == tcphdr->src &&
dirkx	0:355018f44c9f	208	pcb->local_port == tcphdr->dest &&
dirkx	0:355018f44c9f	209	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
dirkx	0:355018f44c9f	210	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
dirkx	0:355018f44c9f	211	/* We don't really care enough to move this PCB to the front
dirkx	0:355018f44c9f	212	of the list since we are not very likely to receive that
dirkx	0:355018f44c9f	213	many segments for connections in TIME-WAIT. */
dirkx	0:355018f44c9f	214	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
dirkx	0:355018f44c9f	215	tcp_timewait_input(pcb);
dirkx	0:355018f44c9f	216	pbuf_free(p);
dirkx	0:355018f44c9f	217	return;
dirkx	0:355018f44c9f	218	}
dirkx	0:355018f44c9f	219	}
dirkx	0:355018f44c9f	220
dirkx	0:355018f44c9f	221	/* Finally, if we still did not get a match, we check all PCBs that
dirkx	0:355018f44c9f	222	are LISTENing for incoming connections. */
dirkx	0:355018f44c9f	223	prev = NULL;
dirkx	0:355018f44c9f	224	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
dirkx	0:355018f44c9f	225	if ((ip_addr_isany(&(lpcb->local_ip)) \|\|
dirkx	0:355018f44c9f	226	ip_addr_cmp(&(lpcb->local_ip), &(iphdr->dest))) &&
dirkx	0:355018f44c9f	227	lpcb->local_port == tcphdr->dest) {
dirkx	0:355018f44c9f	228	/* Move this PCB to the front of the list so that subsequent
dirkx	0:355018f44c9f	229	lookups will be faster (we exploit locality in TCP segment
dirkx	0:355018f44c9f	230	arrivals). */
dirkx	0:355018f44c9f	231	if (prev != NULL) {
dirkx	0:355018f44c9f	232	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
dirkx	0:355018f44c9f	233	/* our successor is the remainder of the listening list */
dirkx	0:355018f44c9f	234	lpcb->next = tcp_listen_pcbs.listen_pcbs;
dirkx	0:355018f44c9f	235	/* put this listening pcb at the head of the listening list */
dirkx	0:355018f44c9f	236	tcp_listen_pcbs.listen_pcbs = lpcb;
dirkx	0:355018f44c9f	237	}
dirkx	0:355018f44c9f	238
dirkx	0:355018f44c9f	239	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
dirkx	0:355018f44c9f	240	tcp_listen_input(lpcb);
dirkx	0:355018f44c9f	241	pbuf_free(p);
dirkx	0:355018f44c9f	242	return;
dirkx	0:355018f44c9f	243	}
dirkx	0:355018f44c9f	244	prev = (struct tcp_pcb *)lpcb;
dirkx	0:355018f44c9f	245	}
dirkx	0:355018f44c9f	246	}
dirkx	0:355018f44c9f	247
dirkx	0:355018f44c9f	248	#if TCP_INPUT_DEBUG
dirkx	0:355018f44c9f	249	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
dirkx	0:355018f44c9f	250	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
dirkx	0:355018f44c9f	251	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
dirkx	0:355018f44c9f	252	#endif /* TCP_INPUT_DEBUG */
dirkx	0:355018f44c9f	253
dirkx	0:355018f44c9f	254
dirkx	0:355018f44c9f	255	if (pcb != NULL) {
dirkx	0:355018f44c9f	256	/* The incoming segment belongs to a connection. */
dirkx	0:355018f44c9f	257	#if TCP_INPUT_DEBUG
dirkx	0:355018f44c9f	258	#if TCP_DEBUG
dirkx	0:355018f44c9f	259	tcp_debug_print_state(pcb->state);
dirkx	0:355018f44c9f	260	#endif /* TCP_DEBUG */
dirkx	0:355018f44c9f	261	#endif /* TCP_INPUT_DEBUG */
dirkx	0:355018f44c9f	262
dirkx	0:355018f44c9f	263	/* Set up a tcp_seg structure. */
dirkx	0:355018f44c9f	264	inseg.next = NULL;
dirkx	0:355018f44c9f	265	inseg.len = p->tot_len;
dirkx	0:355018f44c9f	266	inseg.dataptr = p->payload;
dirkx	0:355018f44c9f	267	inseg.p = p;
dirkx	0:355018f44c9f	268	inseg.tcphdr = tcphdr;
dirkx	0:355018f44c9f	269
dirkx	0:355018f44c9f	270	recv_data = NULL;
dirkx	0:355018f44c9f	271	recv_flags = 0;
dirkx	0:355018f44c9f	272
dirkx	0:355018f44c9f	273	/* If there is data which was previously "refused" by upper layer */
dirkx	0:355018f44c9f	274	if (pcb->refused_data != NULL) {
dirkx	0:355018f44c9f	275	/* Notify again application with data previously received. */
dirkx	0:355018f44c9f	276	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
dirkx	0:355018f44c9f	277	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
dirkx	0:355018f44c9f	278	if (err == ERR_OK) {
dirkx	0:355018f44c9f	279	pcb->refused_data = NULL;
dirkx	0:355018f44c9f	280	} else {
dirkx	0:355018f44c9f	281	/* if err == ERR_ABRT, 'pcb' is already deallocated */
dirkx	0:355018f44c9f	282	/* drop incoming packets, because pcb is "full" */
dirkx	0:355018f44c9f	283	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
dirkx	0:355018f44c9f	284	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	285	snmp_inc_tcpinerrs();
dirkx	0:355018f44c9f	286	pbuf_free(p);
dirkx	0:355018f44c9f	287	return;
dirkx	0:355018f44c9f	288	}
dirkx	0:355018f44c9f	289	}
dirkx	0:355018f44c9f	290	tcp_input_pcb = pcb;
dirkx	0:355018f44c9f	291	err = tcp_process(pcb);
dirkx	0:355018f44c9f	292	/* A return value of ERR_ABRT means that tcp_abort() was called
dirkx	0:355018f44c9f	293	and that the pcb has been freed. If so, we don't do anything. */
dirkx	0:355018f44c9f	294	if (err != ERR_ABRT) {
dirkx	0:355018f44c9f	295	if (recv_flags & TF_RESET) {
dirkx	0:355018f44c9f	296	/* TF_RESET means that the connection was reset by the other
dirkx	0:355018f44c9f	297	end. We then call the error callback to inform the
dirkx	0:355018f44c9f	298	application that the connection is dead before we
dirkx	0:355018f44c9f	299	deallocate the PCB. */
dirkx	0:355018f44c9f	300	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
dirkx	0:355018f44c9f	301	tcp_pcb_remove(&tcp_active_pcbs, pcb);
dirkx	0:355018f44c9f	302	memp_free(MEMP_TCP_PCB, pcb);
dirkx	0:355018f44c9f	303	} else if (recv_flags & TF_CLOSED) {
dirkx	0:355018f44c9f	304	/* The connection has been closed and we will deallocate the
dirkx	0:355018f44c9f	305	PCB. */
dirkx	0:355018f44c9f	306	tcp_pcb_remove(&tcp_active_pcbs, pcb);
dirkx	0:355018f44c9f	307	memp_free(MEMP_TCP_PCB, pcb);
dirkx	0:355018f44c9f	308	} else {
dirkx	0:355018f44c9f	309	err = ERR_OK;
dirkx	0:355018f44c9f	310	/* If the application has registered a "sent" function to be
dirkx	0:355018f44c9f	311	called when new send buffer space is available, we call it
dirkx	0:355018f44c9f	312	now. */
dirkx	0:355018f44c9f	313	if (pcb->acked > 0) {
dirkx	0:355018f44c9f	314	TCP_EVENT_SENT(pcb, pcb->acked, err);
dirkx	0:355018f44c9f	315	if (err == ERR_ABRT) {
dirkx	0:355018f44c9f	316	goto aborted;
dirkx	0:355018f44c9f	317	}
dirkx	0:355018f44c9f	318	}
dirkx	0:355018f44c9f	319
dirkx	0:355018f44c9f	320	if (recv_data != NULL) {
dirkx	0:355018f44c9f	321	if(flags & TCP_PSH) {
dirkx	0:355018f44c9f	322	recv_data->flags \|= PBUF_FLAG_PUSH;
dirkx	0:355018f44c9f	323	}
dirkx	0:355018f44c9f	324
dirkx	0:355018f44c9f	325	/* Notify application that data has been received. */
dirkx	0:355018f44c9f	326	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
dirkx	0:355018f44c9f	327	if (err == ERR_ABRT) {
dirkx	0:355018f44c9f	328	goto aborted;
dirkx	0:355018f44c9f	329	}
dirkx	0:355018f44c9f	330
dirkx	0:355018f44c9f	331	/* If the upper layer can't receive this data, store it */
dirkx	0:355018f44c9f	332	if (err != ERR_OK) {
dirkx	0:355018f44c9f	333	pcb->refused_data = recv_data;
dirkx	0:355018f44c9f	334	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
dirkx	0:355018f44c9f	335	}
dirkx	0:355018f44c9f	336	}
dirkx	0:355018f44c9f	337
dirkx	0:355018f44c9f	338	/* If a FIN segment was received, we call the callback
dirkx	0:355018f44c9f	339	function with a NULL buffer to indicate EOF. */
dirkx	0:355018f44c9f	340	if (recv_flags & TF_GOT_FIN) {
dirkx	0:355018f44c9f	341	/* correct rcv_wnd as the application won't call tcp_recved()
dirkx	0:355018f44c9f	342	for the FIN's seqno */
dirkx	0:355018f44c9f	343	if (pcb->rcv_wnd != TCP_WND) {
dirkx	0:355018f44c9f	344	pcb->rcv_wnd++;
dirkx	0:355018f44c9f	345	}
dirkx	0:355018f44c9f	346	TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
dirkx	0:355018f44c9f	347	if (err == ERR_ABRT) {
dirkx	0:355018f44c9f	348	goto aborted;
dirkx	0:355018f44c9f	349	}
dirkx	0:355018f44c9f	350	}
dirkx	0:355018f44c9f	351
dirkx	0:355018f44c9f	352	tcp_input_pcb = NULL;
dirkx	0:355018f44c9f	353	/* Try to send something out. */
dirkx	0:355018f44c9f	354	tcp_output(pcb);
dirkx	0:355018f44c9f	355	#if TCP_INPUT_DEBUG
dirkx	0:355018f44c9f	356	#if TCP_DEBUG
dirkx	0:355018f44c9f	357	tcp_debug_print_state(pcb->state);
dirkx	0:355018f44c9f	358	#endif /* TCP_DEBUG */
dirkx	0:355018f44c9f	359	#endif /* TCP_INPUT_DEBUG */
dirkx	0:355018f44c9f	360	}
dirkx	0:355018f44c9f	361	}
dirkx	0:355018f44c9f	362	/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
dirkx	0:355018f44c9f	363	Below this line, 'pcb' may not be dereferenced! */
dirkx	0:355018f44c9f	364	aborted:
dirkx	0:355018f44c9f	365	tcp_input_pcb = NULL;
dirkx	0:355018f44c9f	366
dirkx	0:355018f44c9f	367
dirkx	0:355018f44c9f	368	/* give up our reference to inseg.p */
dirkx	0:355018f44c9f	369	if (inseg.p != NULL)
dirkx	0:355018f44c9f	370	{
dirkx	0:355018f44c9f	371	pbuf_free(inseg.p);
dirkx	0:355018f44c9f	372	inseg.p = NULL;
dirkx	0:355018f44c9f	373	}
dirkx	0:355018f44c9f	374	} else {
dirkx	0:355018f44c9f	375
dirkx	0:355018f44c9f	376	/* If no matching PCB was found, send a TCP RST (reset) to the
dirkx	0:355018f44c9f	377	sender. */
dirkx	0:355018f44c9f	378	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
dirkx	0:355018f44c9f	379	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
dirkx	0:355018f44c9f	380	TCP_STATS_INC(tcp.proterr);
dirkx	0:355018f44c9f	381	TCP_STATS_INC(tcp.drop);
dirkx	0:355018f44c9f	382	tcp_rst(ackno, seqno + tcplen,
dirkx	0:355018f44c9f	383	&(iphdr->dest), &(iphdr->src),
dirkx	0:355018f44c9f	384	tcphdr->dest, tcphdr->src);
dirkx	0:355018f44c9f	385	}
dirkx	0:355018f44c9f	386	pbuf_free(p);
dirkx	0:355018f44c9f	387	}
dirkx	0:355018f44c9f	388
dirkx	0:355018f44c9f	389	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
dirkx	0:355018f44c9f	390	PERF_STOP("tcp_input");
dirkx	0:355018f44c9f	391	}
dirkx	0:355018f44c9f	392
dirkx	0:355018f44c9f	393	/**
dirkx	0:355018f44c9f	394	* Called by tcp_input() when a segment arrives for a listening
dirkx	0:355018f44c9f	395	* connection (from tcp_input()).
dirkx	0:355018f44c9f	396	*
dirkx	0:355018f44c9f	397	* @param pcb the tcp_pcb_listen for which a segment arrived
dirkx	0:355018f44c9f	398	* @return ERR_OK if the segment was processed
dirkx	0:355018f44c9f	399	* another err_t on error
dirkx	0:355018f44c9f	400	*
dirkx	0:355018f44c9f	401	* @note the return value is not (yet?) used in tcp_input()
dirkx	0:355018f44c9f	402	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:355018f44c9f	403	* involved is passed as a parameter to this function
dirkx	0:355018f44c9f	404	*/
dirkx	0:355018f44c9f	405	static err_t
dirkx	0:355018f44c9f	406	tcp_listen_input(struct tcp_pcb_listen *pcb)
dirkx	0:355018f44c9f	407	{
dirkx	0:355018f44c9f	408	struct tcp_pcb *npcb;
dirkx	0:355018f44c9f	409	err_t rc;
dirkx	0:355018f44c9f	410
dirkx	0:355018f44c9f	411	/* In the LISTEN state, we check for incoming SYN segments,
dirkx	0:355018f44c9f	412	creates a new PCB, and responds with a SYN\|ACK. */
dirkx	0:355018f44c9f	413	if (flags & TCP_ACK) {
dirkx	0:355018f44c9f	414	/* For incoming segments with the ACK flag set, respond with a
dirkx	0:355018f44c9f	415	RST. */
dirkx	0:355018f44c9f	416	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
dirkx	0:355018f44c9f	417	tcp_rst(ackno + 1, seqno + tcplen,
dirkx	0:355018f44c9f	418	&(iphdr->dest), &(iphdr->src),
dirkx	0:355018f44c9f	419	tcphdr->dest, tcphdr->src);
dirkx	0:355018f44c9f	420	} else if (flags & TCP_SYN) {
dirkx	0:355018f44c9f	421	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
dirkx	0:355018f44c9f	422	#if TCP_LISTEN_BACKLOG
dirkx	0:355018f44c9f	423	if (pcb->accepts_pending >= pcb->backlog) {
dirkx	0:355018f44c9f	424	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
dirkx	0:355018f44c9f	425	return ERR_ABRT;
dirkx	0:355018f44c9f	426	}
dirkx	0:355018f44c9f	427	#endif /* TCP_LISTEN_BACKLOG */
dirkx	0:355018f44c9f	428	npcb = tcp_alloc(pcb->prio);
dirkx	0:355018f44c9f	429	/* If a new PCB could not be created (probably due to lack of memory),
dirkx	0:355018f44c9f	430	we don't do anything, but rely on the sender will retransmit the
dirkx	0:355018f44c9f	431	SYN at a time when we have more memory available. */
dirkx	0:355018f44c9f	432	if (npcb == NULL) {
dirkx	0:355018f44c9f	433	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
dirkx	0:355018f44c9f	434	TCP_STATS_INC(tcp.memerr);
dirkx	0:355018f44c9f	435	return ERR_MEM;
dirkx	0:355018f44c9f	436	}
dirkx	0:355018f44c9f	437	#if TCP_LISTEN_BACKLOG
dirkx	0:355018f44c9f	438	pcb->accepts_pending++;
dirkx	0:355018f44c9f	439	#endif /* TCP_LISTEN_BACKLOG */
dirkx	0:355018f44c9f	440	/* Set up the new PCB. */
dirkx	0:355018f44c9f	441	ip_addr_copy(npcb->local_ip, iphdr->dest);
dirkx	0:355018f44c9f	442	npcb->local_port = pcb->local_port;
dirkx	0:355018f44c9f	443	ip_addr_copy(npcb->remote_ip, iphdr->src);
dirkx	0:355018f44c9f	444	npcb->remote_port = tcphdr->src;
dirkx	0:355018f44c9f	445	npcb->state = SYN_RCVD;
dirkx	0:355018f44c9f	446	npcb->rcv_nxt = seqno + 1;
dirkx	0:355018f44c9f	447	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
dirkx	0:355018f44c9f	448	npcb->snd_wnd = tcphdr->wnd;
dirkx	0:355018f44c9f	449	npcb->ssthresh = npcb->snd_wnd;
dirkx	0:355018f44c9f	450	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
dirkx	0:355018f44c9f	451	npcb->callback_arg = pcb->callback_arg;
dirkx	0:355018f44c9f	452	#if LWIP_CALLBACK_API
dirkx	0:355018f44c9f	453	npcb->accept = pcb->accept;
dirkx	0:355018f44c9f	454	#endif /* LWIP_CALLBACK_API */
dirkx	0:355018f44c9f	455	/* inherit socket options */
dirkx	0:355018f44c9f	456	npcb->so_options = pcb->so_options & (SOF_DEBUG\|SOF_DONTROUTE\|SOF_KEEPALIVE\|SOF_OOBINLINE\|SOF_LINGER);
dirkx	0:355018f44c9f	457	/* Register the new PCB so that we can begin receiving segments
dirkx	0:355018f44c9f	458	for it. */
dirkx	0:355018f44c9f	459	TCP_REG(&tcp_active_pcbs, npcb);
dirkx	0:355018f44c9f	460
dirkx	0:355018f44c9f	461	/* Parse any options in the SYN. */
dirkx	0:355018f44c9f	462	tcp_parseopt(npcb);
dirkx	0:355018f44c9f	463	#if TCP_CALCULATE_EFF_SEND_MSS
dirkx	0:355018f44c9f	464	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
dirkx	0:355018f44c9f	465	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
dirkx	0:355018f44c9f	466
dirkx	0:355018f44c9f	467	snmp_inc_tcppassiveopens();
dirkx	0:355018f44c9f	468
dirkx	0:355018f44c9f	469	/* Send a SYN\|ACK together with the MSS option. */
dirkx	0:355018f44c9f	470	rc = tcp_enqueue_flags(npcb, TCP_SYN \| TCP_ACK);
dirkx	0:355018f44c9f	471	if (rc != ERR_OK) {
dirkx	0:355018f44c9f	472	tcp_abandon(npcb, 0);
dirkx	0:355018f44c9f	473	return rc;
dirkx	0:355018f44c9f	474	}
dirkx	0:355018f44c9f	475	return tcp_output(npcb);
dirkx	0:355018f44c9f	476	}
dirkx	0:355018f44c9f	477	return ERR_OK;
dirkx	0:355018f44c9f	478	}
dirkx	0:355018f44c9f	479
dirkx	0:355018f44c9f	480	/**
dirkx	0:355018f44c9f	481	* Called by tcp_input() when a segment arrives for a connection in
dirkx	0:355018f44c9f	482	* TIME_WAIT.
dirkx	0:355018f44c9f	483	*
dirkx	0:355018f44c9f	484	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:355018f44c9f	485	*
dirkx	0:355018f44c9f	486	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:355018f44c9f	487	* involved is passed as a parameter to this function
dirkx	0:355018f44c9f	488	*/
dirkx	0:355018f44c9f	489	static err_t
dirkx	0:355018f44c9f	490	tcp_timewait_input(struct tcp_pcb *pcb)
dirkx	0:355018f44c9f	491	{
dirkx	0:355018f44c9f	492	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
dirkx	0:355018f44c9f	493	/* RFC 793 3.9 Event Processing - Segment Arrives:
dirkx	0:355018f44c9f	494	* - first check sequence number - we skip that one in TIME_WAIT (always
dirkx	0:355018f44c9f	495	* acceptable since we only send ACKs)
dirkx	0:355018f44c9f	496	* - second check the RST bit (... return) */
dirkx	0:355018f44c9f	497	if (flags & TCP_RST) {
dirkx	0:355018f44c9f	498	return ERR_OK;
dirkx	0:355018f44c9f	499	}
dirkx	0:355018f44c9f	500	/* - fourth, check the SYN bit, */
dirkx	0:355018f44c9f	501	if (flags & TCP_SYN) {
dirkx	0:355018f44c9f	502	/* If an incoming segment is not acceptable, an acknowledgment
dirkx	0:355018f44c9f	503	should be sent in reply */
dirkx	0:355018f44c9f	504	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
dirkx	0:355018f44c9f	505	/* If the SYN is in the window it is an error, send a reset */
dirkx	0:355018f44c9f	506	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:355018f44c9f	507	tcphdr->dest, tcphdr->src);
dirkx	0:355018f44c9f	508	return ERR_OK;
dirkx	0:355018f44c9f	509	}
dirkx	0:355018f44c9f	510	} else if (flags & TCP_FIN) {
dirkx	0:355018f44c9f	511	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
dirkx	0:355018f44c9f	512	Restart the 2 MSL time-wait timeout.*/
dirkx	0:355018f44c9f	513	pcb->tmr = tcp_ticks;
dirkx	0:355018f44c9f	514	}
dirkx	0:355018f44c9f	515
dirkx	0:355018f44c9f	516	if ((tcplen > 0)) {
dirkx	0:355018f44c9f	517	/* Acknowledge data, FIN or out-of-window SYN */
dirkx	0:355018f44c9f	518	pcb->flags \|= TF_ACK_NOW;
dirkx	0:355018f44c9f	519	return tcp_output(pcb);
dirkx	0:355018f44c9f	520	}
dirkx	0:355018f44c9f	521	return ERR_OK;
dirkx	0:355018f44c9f	522	}
dirkx	0:355018f44c9f	523
dirkx	0:355018f44c9f	524	/**
dirkx	0:355018f44c9f	525	* Implements the TCP state machine. Called by tcp_input. In some
dirkx	0:355018f44c9f	526	* states tcp_receive() is called to receive data. The tcp_seg
dirkx	0:355018f44c9f	527	* argument will be freed by the caller (tcp_input()) unless the
dirkx	0:355018f44c9f	528	* recv_data pointer in the pcb is set.
dirkx	0:355018f44c9f	529	*
dirkx	0:355018f44c9f	530	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:355018f44c9f	531	*
dirkx	0:355018f44c9f	532	* @note the segment which arrived is saved in global variables, therefore only the pcb
dirkx	0:355018f44c9f	533	* involved is passed as a parameter to this function
dirkx	0:355018f44c9f	534	*/
dirkx	0:355018f44c9f	535	static err_t
dirkx	0:355018f44c9f	536	tcp_process(struct tcp_pcb *pcb)
dirkx	0:355018f44c9f	537	{
dirkx	0:355018f44c9f	538	struct tcp_seg *rseg;
dirkx	0:355018f44c9f	539	u8_t acceptable = 0;
dirkx	0:355018f44c9f	540	err_t err;
dirkx	0:355018f44c9f	541
dirkx	0:355018f44c9f	542	err = ERR_OK;
dirkx	0:355018f44c9f	543
dirkx	0:355018f44c9f	544	/* Process incoming RST segments. */
dirkx	0:355018f44c9f	545	if (flags & TCP_RST) {
dirkx	0:355018f44c9f	546	/* First, determine if the reset is acceptable. */
dirkx	0:355018f44c9f	547	if (pcb->state == SYN_SENT) {
dirkx	0:355018f44c9f	548	if (ackno == pcb->snd_nxt) {
dirkx	0:355018f44c9f	549	acceptable = 1;
dirkx	0:355018f44c9f	550	}
dirkx	0:355018f44c9f	551	} else {
dirkx	0:355018f44c9f	552	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
dirkx	0:355018f44c9f	553	pcb->rcv_nxt+pcb->rcv_wnd)) {
dirkx	0:355018f44c9f	554	acceptable = 1;
dirkx	0:355018f44c9f	555	}
dirkx	0:355018f44c9f	556	}
dirkx	0:355018f44c9f	557
dirkx	0:355018f44c9f	558	if (acceptable) {
dirkx	0:355018f44c9f	559	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
dirkx	0:355018f44c9f	560	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
dirkx	0:355018f44c9f	561	recv_flags \|= TF_RESET;
dirkx	0:355018f44c9f	562	pcb->flags &= ~TF_ACK_DELAY;
dirkx	0:355018f44c9f	563	return ERR_RST;
dirkx	0:355018f44c9f	564	} else {
dirkx	0:355018f44c9f	565	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
dirkx	0:355018f44c9f	566	seqno, pcb->rcv_nxt));
dirkx	0:355018f44c9f	567	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
dirkx	0:355018f44c9f	568	seqno, pcb->rcv_nxt));
dirkx	0:355018f44c9f	569	return ERR_OK;
dirkx	0:355018f44c9f	570	}
dirkx	0:355018f44c9f	571	}
dirkx	0:355018f44c9f	572
dirkx	0:355018f44c9f	573	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
dirkx	0:355018f44c9f	574	/* Cope with new connection attempt after remote end crashed */
dirkx	0:355018f44c9f	575	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	576	return ERR_OK;
dirkx	0:355018f44c9f	577	}
dirkx	0:355018f44c9f	578
dirkx	0:355018f44c9f	579	if ((pcb->flags & TF_RXCLOSED) == 0) {
dirkx	0:355018f44c9f	580	/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
dirkx	0:355018f44c9f	581	pcb->tmr = tcp_ticks;
dirkx	0:355018f44c9f	582	}
dirkx	0:355018f44c9f	583	pcb->keep_cnt_sent = 0;
dirkx	0:355018f44c9f	584
dirkx	0:355018f44c9f	585	tcp_parseopt(pcb);
dirkx	0:355018f44c9f	586
dirkx	0:355018f44c9f	587	/* Do different things depending on the TCP state. */
dirkx	0:355018f44c9f	588	switch (pcb->state) {
dirkx	0:355018f44c9f	589	case SYN_SENT:
dirkx	0:355018f44c9f	590	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
dirkx	0:355018f44c9f	591	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
dirkx	0:355018f44c9f	592	/* received SYN ACK with expected sequence number? */
dirkx	0:355018f44c9f	593	if ((flags & TCP_ACK) && (flags & TCP_SYN)
dirkx	0:355018f44c9f	594	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
dirkx	0:355018f44c9f	595	pcb->snd_buf++;
dirkx	0:355018f44c9f	596	pcb->rcv_nxt = seqno + 1;
dirkx	0:355018f44c9f	597	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
dirkx	0:355018f44c9f	598	pcb->lastack = ackno;
dirkx	0:355018f44c9f	599	pcb->snd_wnd = tcphdr->wnd;
dirkx	0:355018f44c9f	600	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
dirkx	0:355018f44c9f	601	pcb->state = ESTABLISHED;
dirkx	0:355018f44c9f	602
dirkx	0:355018f44c9f	603	#if TCP_CALCULATE_EFF_SEND_MSS
dirkx	0:355018f44c9f	604	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
dirkx	0:355018f44c9f	605	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
dirkx	0:355018f44c9f	606
dirkx	0:355018f44c9f	607	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
dirkx	0:355018f44c9f	608	* but for the default value of pcb->mss) */
dirkx	0:355018f44c9f	609	pcb->ssthresh = pcb->mss * 10;
dirkx	0:355018f44c9f	610
dirkx	0:355018f44c9f	611	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
dirkx	0:355018f44c9f	612	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
dirkx	0:355018f44c9f	613	--pcb->snd_queuelen;
dirkx	0:355018f44c9f	614	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
dirkx	0:355018f44c9f	615	rseg = pcb->unacked;
dirkx	0:355018f44c9f	616	pcb->unacked = rseg->next;
dirkx	0:355018f44c9f	617
dirkx	0:355018f44c9f	618	/* If there's nothing left to acknowledge, stop the retransmit
dirkx	0:355018f44c9f	619	timer, otherwise reset it to start again */
dirkx	0:355018f44c9f	620	if(pcb->unacked == NULL)
dirkx	0:355018f44c9f	621	pcb->rtime = -1;
dirkx	0:355018f44c9f	622	else {
dirkx	0:355018f44c9f	623	pcb->rtime = 0;
dirkx	0:355018f44c9f	624	pcb->nrtx = 0;
dirkx	0:355018f44c9f	625	}
dirkx	0:355018f44c9f	626
dirkx	0:355018f44c9f	627	tcp_seg_free(rseg);
dirkx	0:355018f44c9f	628
dirkx	0:355018f44c9f	629	/* Call the user specified function to call when sucessfully
dirkx	0:355018f44c9f	630	* connected. */
dirkx	0:355018f44c9f	631	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
dirkx	0:355018f44c9f	632	if (err == ERR_ABRT) {
dirkx	0:355018f44c9f	633	return ERR_ABRT;
dirkx	0:355018f44c9f	634	}
dirkx	0:355018f44c9f	635	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	636	}
dirkx	0:355018f44c9f	637	/* received ACK? possibly a half-open connection */
dirkx	0:355018f44c9f	638	else if (flags & TCP_ACK) {
dirkx	0:355018f44c9f	639	/* send a RST to bring the other side in a non-synchronized state. */
dirkx	0:355018f44c9f	640	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:355018f44c9f	641	tcphdr->dest, tcphdr->src);
dirkx	0:355018f44c9f	642	}
dirkx	0:355018f44c9f	643	break;
dirkx	0:355018f44c9f	644	case SYN_RCVD:
dirkx	0:355018f44c9f	645	if (flags & TCP_ACK) {
dirkx	0:355018f44c9f	646	/* expected ACK number? */
dirkx	0:355018f44c9f	647	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
dirkx	0:355018f44c9f	648	u16_t old_cwnd;
dirkx	0:355018f44c9f	649	pcb->state = ESTABLISHED;
dirkx	0:355018f44c9f	650	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:355018f44c9f	651	#if LWIP_CALLBACK_API
dirkx	0:355018f44c9f	652	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
dirkx	0:355018f44c9f	653	#endif
dirkx	0:355018f44c9f	654	/* Call the accept function. */
dirkx	0:355018f44c9f	655	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
dirkx	0:355018f44c9f	656	if (err != ERR_OK) {
dirkx	0:355018f44c9f	657	/* If the accept function returns with an error, we abort
dirkx	0:355018f44c9f	658	* the connection. */
dirkx	0:355018f44c9f	659	/* Already aborted? */
dirkx	0:355018f44c9f	660	if (err != ERR_ABRT) {
dirkx	0:355018f44c9f	661	tcp_abort(pcb);
dirkx	0:355018f44c9f	662	}
dirkx	0:355018f44c9f	663	return ERR_ABRT;
dirkx	0:355018f44c9f	664	}
dirkx	0:355018f44c9f	665	old_cwnd = pcb->cwnd;
dirkx	0:355018f44c9f	666	/* If there was any data contained within this ACK,
dirkx	0:355018f44c9f	667	* we'd better pass it on to the application as well. */
dirkx	0:355018f44c9f	668	tcp_receive(pcb);
dirkx	0:355018f44c9f	669
dirkx	0:355018f44c9f	670	/* Prevent ACK for SYN to generate a sent event */
dirkx	0:355018f44c9f	671	if (pcb->acked != 0) {
dirkx	0:355018f44c9f	672	pcb->acked--;
dirkx	0:355018f44c9f	673	}
dirkx	0:355018f44c9f	674
dirkx	0:355018f44c9f	675	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
dirkx	0:355018f44c9f	676
dirkx	0:355018f44c9f	677	if (recv_flags & TF_GOT_FIN) {
dirkx	0:355018f44c9f	678	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	679	pcb->state = CLOSE_WAIT;
dirkx	0:355018f44c9f	680	}
dirkx	0:355018f44c9f	681	} else {
dirkx	0:355018f44c9f	682	/* incorrect ACK number, send RST */
dirkx	0:355018f44c9f	683	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
dirkx	0:355018f44c9f	684	tcphdr->dest, tcphdr->src);
dirkx	0:355018f44c9f	685	}
dirkx	0:355018f44c9f	686	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
dirkx	0:355018f44c9f	687	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
dirkx	0:355018f44c9f	688	tcp_rexmit(pcb);
dirkx	0:355018f44c9f	689	}
dirkx	0:355018f44c9f	690	break;
dirkx	0:355018f44c9f	691	case CLOSE_WAIT:
dirkx	0:355018f44c9f	692	/* FALLTHROUGH */
dirkx	0:355018f44c9f	693	case ESTABLISHED:
dirkx	0:355018f44c9f	694	tcp_receive(pcb);
dirkx	0:355018f44c9f	695	if (recv_flags & TF_GOT_FIN) { /* passive close */
dirkx	0:355018f44c9f	696	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	697	pcb->state = CLOSE_WAIT;
dirkx	0:355018f44c9f	698	}
dirkx	0:355018f44c9f	699	break;
dirkx	0:355018f44c9f	700	case FIN_WAIT_1:
dirkx	0:355018f44c9f	701	tcp_receive(pcb);
dirkx	0:355018f44c9f	702	if (recv_flags & TF_GOT_FIN) {
dirkx	0:355018f44c9f	703	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
dirkx	0:355018f44c9f	704	LWIP_DEBUGF(TCP_DEBUG,
dirkx	0:355018f44c9f	705	("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:355018f44c9f	706	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	707	tcp_pcb_purge(pcb);
dirkx	0:355018f44c9f	708	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:355018f44c9f	709	pcb->state = TIME_WAIT;
dirkx	0:355018f44c9f	710	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:355018f44c9f	711	} else {
dirkx	0:355018f44c9f	712	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	713	pcb->state = CLOSING;
dirkx	0:355018f44c9f	714	}
dirkx	0:355018f44c9f	715	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
dirkx	0:355018f44c9f	716	pcb->state = FIN_WAIT_2;
dirkx	0:355018f44c9f	717	}
dirkx	0:355018f44c9f	718	break;
dirkx	0:355018f44c9f	719	case FIN_WAIT_2:
dirkx	0:355018f44c9f	720	tcp_receive(pcb);
dirkx	0:355018f44c9f	721	if (recv_flags & TF_GOT_FIN) {
dirkx	0:355018f44c9f	722	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:355018f44c9f	723	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	724	tcp_pcb_purge(pcb);
dirkx	0:355018f44c9f	725	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:355018f44c9f	726	pcb->state = TIME_WAIT;
dirkx	0:355018f44c9f	727	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:355018f44c9f	728	}
dirkx	0:355018f44c9f	729	break;
dirkx	0:355018f44c9f	730	case CLOSING:
dirkx	0:355018f44c9f	731	tcp_receive(pcb);
dirkx	0:355018f44c9f	732	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
dirkx	0:355018f44c9f	733	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:355018f44c9f	734	tcp_pcb_purge(pcb);
dirkx	0:355018f44c9f	735	TCP_RMV(&tcp_active_pcbs, pcb);
dirkx	0:355018f44c9f	736	pcb->state = TIME_WAIT;
dirkx	0:355018f44c9f	737	TCP_REG(&tcp_tw_pcbs, pcb);
dirkx	0:355018f44c9f	738	}
dirkx	0:355018f44c9f	739	break;
dirkx	0:355018f44c9f	740	case LAST_ACK:
dirkx	0:355018f44c9f	741	tcp_receive(pcb);
dirkx	0:355018f44c9f	742	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
dirkx	0:355018f44c9f	743	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
dirkx	0:355018f44c9f	744	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
dirkx	0:355018f44c9f	745	recv_flags \|= TF_CLOSED;
dirkx	0:355018f44c9f	746	}
dirkx	0:355018f44c9f	747	break;
dirkx	0:355018f44c9f	748	default:
dirkx	0:355018f44c9f	749	break;
dirkx	0:355018f44c9f	750	}
dirkx	0:355018f44c9f	751	return ERR_OK;
dirkx	0:355018f44c9f	752	}
dirkx	0:355018f44c9f	753
dirkx	0:355018f44c9f	754	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	755	/**
dirkx	0:355018f44c9f	756	* Insert segment into the list (segments covered with new one will be deleted)
dirkx	0:355018f44c9f	757	*
dirkx	0:355018f44c9f	758	* Called from tcp_receive()
dirkx	0:355018f44c9f	759	*/
dirkx	0:355018f44c9f	760	static void
dirkx	0:355018f44c9f	761	tcp_oos_insert_segment(struct tcp_seg cseg, struct tcp_seg next)
dirkx	0:355018f44c9f	762	{
dirkx	0:355018f44c9f	763	struct tcp_seg *old_seg;
dirkx	0:355018f44c9f	764
dirkx	0:355018f44c9f	765	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	766	/* received segment overlaps all following segments */
dirkx	0:355018f44c9f	767	tcp_segs_free(next);
dirkx	0:355018f44c9f	768	next = NULL;
dirkx	0:355018f44c9f	769	}
dirkx	0:355018f44c9f	770	else {
dirkx	0:355018f44c9f	771	/* delete some following segments
dirkx	0:355018f44c9f	772	oos queue may have segments with FIN flag */
dirkx	0:355018f44c9f	773	while (next &&
dirkx	0:355018f44c9f	774	TCP_SEQ_GEQ((seqno + cseg->len),
dirkx	0:355018f44c9f	775	(next->tcphdr->seqno + next->len))) {
dirkx	0:355018f44c9f	776	/* cseg with FIN already processed */
dirkx	0:355018f44c9f	777	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	778	TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
dirkx	0:355018f44c9f	779	}
dirkx	0:355018f44c9f	780	old_seg = next;
dirkx	0:355018f44c9f	781	next = next->next;
dirkx	0:355018f44c9f	782	tcp_seg_free(old_seg);
dirkx	0:355018f44c9f	783	}
dirkx	0:355018f44c9f	784	if (next &&
dirkx	0:355018f44c9f	785	TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
dirkx	0:355018f44c9f	786	/* We need to trim the incoming segment. */
dirkx	0:355018f44c9f	787	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
dirkx	0:355018f44c9f	788	pbuf_realloc(cseg->p, cseg->len);
dirkx	0:355018f44c9f	789	}
dirkx	0:355018f44c9f	790	}
dirkx	0:355018f44c9f	791	cseg->next = next;
dirkx	0:355018f44c9f	792	}
dirkx	0:355018f44c9f	793	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:355018f44c9f	794
dirkx	0:355018f44c9f	795	/**
dirkx	0:355018f44c9f	796	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
dirkx	0:355018f44c9f	797	* data, and if so frees the memory of the buffered data. Next, is places the
dirkx	0:355018f44c9f	798	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
dirkx	0:355018f44c9f	799	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
dirkx	0:355018f44c9f	800	* i it has been removed from the buffer.
dirkx	0:355018f44c9f	801	*
dirkx	0:355018f44c9f	802	* If the incoming segment constitutes an ACK for a segment that was used for RTT
dirkx	0:355018f44c9f	803	* estimation, the RTT is estimated here as well.
dirkx	0:355018f44c9f	804	*
dirkx	0:355018f44c9f	805	* Called from tcp_process().
dirkx	0:355018f44c9f	806	*/
dirkx	0:355018f44c9f	807	static void
dirkx	0:355018f44c9f	808	tcp_receive(struct tcp_pcb *pcb)
dirkx	0:355018f44c9f	809	{
dirkx	0:355018f44c9f	810	struct tcp_seg *next;
dirkx	0:355018f44c9f	811	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	812	struct tcp_seg prev, cseg;
dirkx	0:355018f44c9f	813	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:355018f44c9f	814	struct pbuf *p;
dirkx	0:355018f44c9f	815	s32_t off;
dirkx	0:355018f44c9f	816	s16_t m;
dirkx	0:355018f44c9f	817	u32_t right_wnd_edge;
dirkx	0:355018f44c9f	818	u16_t new_tot_len;
dirkx	0:355018f44c9f	819	int found_dupack = 0;
dirkx	0:355018f44c9f	820
dirkx	0:355018f44c9f	821	if (flags & TCP_ACK) {
dirkx	0:355018f44c9f	822	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
dirkx	0:355018f44c9f	823
dirkx	0:355018f44c9f	824	/* Update window. */
dirkx	0:355018f44c9f	825	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
dirkx	0:355018f44c9f	826	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
dirkx	0:355018f44c9f	827	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
dirkx	0:355018f44c9f	828	pcb->snd_wnd = tcphdr->wnd;
dirkx	0:355018f44c9f	829	pcb->snd_wl1 = seqno;
dirkx	0:355018f44c9f	830	pcb->snd_wl2 = ackno;
dirkx	0:355018f44c9f	831	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
dirkx	0:355018f44c9f	832	pcb->persist_backoff = 0;
dirkx	0:355018f44c9f	833	}
dirkx	0:355018f44c9f	834	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
dirkx	0:355018f44c9f	835	#if TCP_WND_DEBUG
dirkx	0:355018f44c9f	836	} else {
dirkx	0:355018f44c9f	837	if (pcb->snd_wnd != tcphdr->wnd) {
dirkx	0:355018f44c9f	838	LWIP_DEBUGF(TCP_WND_DEBUG,
dirkx	0:355018f44c9f	839	("tcp_receive: no window update lastack %"U32_F" ackno %"
dirkx	0:355018f44c9f	840	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
dirkx	0:355018f44c9f	841	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
dirkx	0:355018f44c9f	842	}
dirkx	0:355018f44c9f	843	#endif /* TCP_WND_DEBUG */
dirkx	0:355018f44c9f	844	}
dirkx	0:355018f44c9f	845
dirkx	0:355018f44c9f	846	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
dirkx	0:355018f44c9f	847	* duplicate ack if:
dirkx	0:355018f44c9f	848	* 1) It doesn't ACK new data
dirkx	0:355018f44c9f	849	* 2) length of received packet is zero (i.e. no payload)
dirkx	0:355018f44c9f	850	* 3) the advertised window hasn't changed
dirkx	0:355018f44c9f	851	* 4) There is outstanding unacknowledged data (retransmission timer running)
dirkx	0:355018f44c9f	852	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
dirkx	0:355018f44c9f	853	*
dirkx	0:355018f44c9f	854	* If it passes all five, should process as a dupack:
dirkx	0:355018f44c9f	855	* a) dupacks < 3: do nothing
dirkx	0:355018f44c9f	856	* b) dupacks == 3: fast retransmit
dirkx	0:355018f44c9f	857	* c) dupacks > 3: increase cwnd
dirkx	0:355018f44c9f	858	*
dirkx	0:355018f44c9f	859	* If it only passes 1-3, should reset dupack counter (and add to
dirkx	0:355018f44c9f	860	* stats, which we don't do in lwIP)
dirkx	0:355018f44c9f	861	*
dirkx	0:355018f44c9f	862	* If it only passes 1, should reset dupack counter
dirkx	0:355018f44c9f	863	*
dirkx	0:355018f44c9f	864	*/
dirkx	0:355018f44c9f	865
dirkx	0:355018f44c9f	866	/* Clause 1 */
dirkx	0:355018f44c9f	867	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
dirkx	0:355018f44c9f	868	pcb->acked = 0;
dirkx	0:355018f44c9f	869	/* Clause 2 */
dirkx	0:355018f44c9f	870	if (tcplen == 0) {
dirkx	0:355018f44c9f	871	/* Clause 3 */
dirkx	0:355018f44c9f	872	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
dirkx	0:355018f44c9f	873	/* Clause 4 */
dirkx	0:355018f44c9f	874	if (pcb->rtime >= 0) {
dirkx	0:355018f44c9f	875	/* Clause 5 */
dirkx	0:355018f44c9f	876	if (pcb->lastack == ackno) {
dirkx	0:355018f44c9f	877	found_dupack = 1;
dirkx	0:355018f44c9f	878	if (pcb->dupacks + 1 > pcb->dupacks)
dirkx	0:355018f44c9f	879	++pcb->dupacks;
dirkx	0:355018f44c9f	880	if (pcb->dupacks > 3) {
dirkx	0:355018f44c9f	881	/* Inflate the congestion window, but not if it means that
dirkx	0:355018f44c9f	882	the value overflows. */
dirkx	0:355018f44c9f	883	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
dirkx	0:355018f44c9f	884	pcb->cwnd += pcb->mss;
dirkx	0:355018f44c9f	885	}
dirkx	0:355018f44c9f	886	} else if (pcb->dupacks == 3) {
dirkx	0:355018f44c9f	887	/* Do fast retransmit */
dirkx	0:355018f44c9f	888	tcp_rexmit_fast(pcb);
dirkx	0:355018f44c9f	889	}
dirkx	0:355018f44c9f	890	}
dirkx	0:355018f44c9f	891	}
dirkx	0:355018f44c9f	892	}
dirkx	0:355018f44c9f	893	}
dirkx	0:355018f44c9f	894	/* If Clause (1) or more is true, but not a duplicate ack, reset
dirkx	0:355018f44c9f	895	* count of consecutive duplicate acks */
dirkx	0:355018f44c9f	896	if (!found_dupack) {
dirkx	0:355018f44c9f	897	pcb->dupacks = 0;
dirkx	0:355018f44c9f	898	}
dirkx	0:355018f44c9f	899	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
dirkx	0:355018f44c9f	900	/* We come here when the ACK acknowledges new data. */
dirkx	0:355018f44c9f	901
dirkx	0:355018f44c9f	902	/* Reset the "IN Fast Retransmit" flag, since we are no longer
dirkx	0:355018f44c9f	903	in fast retransmit. Also reset the congestion window to the
dirkx	0:355018f44c9f	904	slow start threshold. */
dirkx	0:355018f44c9f	905	if (pcb->flags & TF_INFR) {
dirkx	0:355018f44c9f	906	pcb->flags &= ~TF_INFR;
dirkx	0:355018f44c9f	907	pcb->cwnd = pcb->ssthresh;
dirkx	0:355018f44c9f	908	}
dirkx	0:355018f44c9f	909
dirkx	0:355018f44c9f	910	/* Reset the number of retransmissions. */
dirkx	0:355018f44c9f	911	pcb->nrtx = 0;
dirkx	0:355018f44c9f	912
dirkx	0:355018f44c9f	913	/* Reset the retransmission time-out. */
dirkx	0:355018f44c9f	914	pcb->rto = (pcb->sa >> 3) + pcb->sv;
dirkx	0:355018f44c9f	915
dirkx	0:355018f44c9f	916	/* Update the send buffer space. Diff between the two can never exceed 64K? */
dirkx	0:355018f44c9f	917	pcb->acked = (u16_t)(ackno - pcb->lastack);
dirkx	0:355018f44c9f	918
dirkx	0:355018f44c9f	919	pcb->snd_buf += pcb->acked;
dirkx	0:355018f44c9f	920
dirkx	0:355018f44c9f	921	/* Reset the fast retransmit variables. */
dirkx	0:355018f44c9f	922	pcb->dupacks = 0;
dirkx	0:355018f44c9f	923	pcb->lastack = ackno;
dirkx	0:355018f44c9f	924
dirkx	0:355018f44c9f	925	/* Update the congestion control variables (cwnd and
dirkx	0:355018f44c9f	926	ssthresh). */
dirkx	0:355018f44c9f	927	if (pcb->state >= ESTABLISHED) {
dirkx	0:355018f44c9f	928	if (pcb->cwnd < pcb->ssthresh) {
dirkx	0:355018f44c9f	929	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
dirkx	0:355018f44c9f	930	pcb->cwnd += pcb->mss;
dirkx	0:355018f44c9f	931	}
dirkx	0:355018f44c9f	932	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
dirkx	0:355018f44c9f	933	} else {
dirkx	0:355018f44c9f	934	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
dirkx	0:355018f44c9f	935	if (new_cwnd > pcb->cwnd) {
dirkx	0:355018f44c9f	936	pcb->cwnd = new_cwnd;
dirkx	0:355018f44c9f	937	}
dirkx	0:355018f44c9f	938	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
dirkx	0:355018f44c9f	939	}
dirkx	0:355018f44c9f	940	}
dirkx	0:355018f44c9f	941	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
dirkx	0:355018f44c9f	942	ackno,
dirkx	0:355018f44c9f	943	pcb->unacked != NULL?
dirkx	0:355018f44c9f	944	ntohl(pcb->unacked->tcphdr->seqno): 0,
dirkx	0:355018f44c9f	945	pcb->unacked != NULL?
dirkx	0:355018f44c9f	946	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
dirkx	0:355018f44c9f	947
dirkx	0:355018f44c9f	948	/* Remove segment from the unacknowledged list if the incoming
dirkx	0:355018f44c9f	949	ACK acknowlegdes them. */
dirkx	0:355018f44c9f	950	while (pcb->unacked != NULL &&
dirkx	0:355018f44c9f	951	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
dirkx	0:355018f44c9f	952	TCP_TCPLEN(pcb->unacked), ackno)) {
dirkx	0:355018f44c9f	953	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
dirkx	0:355018f44c9f	954	ntohl(pcb->unacked->tcphdr->seqno),
dirkx	0:355018f44c9f	955	ntohl(pcb->unacked->tcphdr->seqno) +
dirkx	0:355018f44c9f	956	TCP_TCPLEN(pcb->unacked)));
dirkx	0:355018f44c9f	957
dirkx	0:355018f44c9f	958	next = pcb->unacked;
dirkx	0:355018f44c9f	959	pcb->unacked = pcb->unacked->next;
dirkx	0:355018f44c9f	960
dirkx	0:355018f44c9f	961	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
dirkx	0:355018f44c9f	962	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
dirkx	0:355018f44c9f	963	/* Prevent ACK for FIN to generate a sent event */
dirkx	0:355018f44c9f	964	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
dirkx	0:355018f44c9f	965	pcb->acked--;
dirkx	0:355018f44c9f	966	}
dirkx	0:355018f44c9f	967
dirkx	0:355018f44c9f	968	pcb->snd_queuelen -= pbuf_clen(next->p);
dirkx	0:355018f44c9f	969	tcp_seg_free(next);
dirkx	0:355018f44c9f	970
dirkx	0:355018f44c9f	971	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
dirkx	0:355018f44c9f	972	if (pcb->snd_queuelen != 0) {
dirkx	0:355018f44c9f	973	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
dirkx	0:355018f44c9f	974	pcb->unsent != NULL);
dirkx	0:355018f44c9f	975	}
dirkx	0:355018f44c9f	976	}
dirkx	0:355018f44c9f	977
dirkx	0:355018f44c9f	978	/* If there's nothing left to acknowledge, stop the retransmit
dirkx	0:355018f44c9f	979	timer, otherwise reset it to start again */
dirkx	0:355018f44c9f	980	if(pcb->unacked == NULL)
dirkx	0:355018f44c9f	981	pcb->rtime = -1;
dirkx	0:355018f44c9f	982	else
dirkx	0:355018f44c9f	983	pcb->rtime = 0;
dirkx	0:355018f44c9f	984
dirkx	0:355018f44c9f	985	pcb->polltmr = 0;
dirkx	0:355018f44c9f	986	} else {
dirkx	0:355018f44c9f	987	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
dirkx	0:355018f44c9f	988	pcb->acked = 0;
dirkx	0:355018f44c9f	989	}
dirkx	0:355018f44c9f	990
dirkx	0:355018f44c9f	991	/* We go through the ->unsent list to see if any of the segments
dirkx	0:355018f44c9f	992	on the list are acknowledged by the ACK. This may seem
dirkx	0:355018f44c9f	993	strange since an "unsent" segment shouldn't be acked. The
dirkx	0:355018f44c9f	994	rationale is that lwIP puts all outstanding segments on the
dirkx	0:355018f44c9f	995	->unsent list after a retransmission, so these segments may
dirkx	0:355018f44c9f	996	in fact have been sent once. */
dirkx	0:355018f44c9f	997	while (pcb->unsent != NULL &&
dirkx	0:355018f44c9f	998	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
dirkx	0:355018f44c9f	999	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
dirkx	0:355018f44c9f	1000	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
dirkx	0:355018f44c9f	1001	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
dirkx	0:355018f44c9f	1002	TCP_TCPLEN(pcb->unsent)));
dirkx	0:355018f44c9f	1003
dirkx	0:355018f44c9f	1004	next = pcb->unsent;
dirkx	0:355018f44c9f	1005	pcb->unsent = pcb->unsent->next;
dirkx	0:355018f44c9f	1006	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
dirkx	0:355018f44c9f	1007	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
dirkx	0:355018f44c9f	1008	/* Prevent ACK for FIN to generate a sent event */
dirkx	0:355018f44c9f	1009	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
dirkx	0:355018f44c9f	1010	pcb->acked--;
dirkx	0:355018f44c9f	1011	}
dirkx	0:355018f44c9f	1012	pcb->snd_queuelen -= pbuf_clen(next->p);
dirkx	0:355018f44c9f	1013	tcp_seg_free(next);
dirkx	0:355018f44c9f	1014	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
dirkx	0:355018f44c9f	1015	if (pcb->snd_queuelen != 0) {
dirkx	0:355018f44c9f	1016	LWIP_ASSERT("tcp_receive: valid queue length",
dirkx	0:355018f44c9f	1017	pcb->unacked != NULL \|\| pcb->unsent != NULL);
dirkx	0:355018f44c9f	1018	}
dirkx	0:355018f44c9f	1019	}
dirkx	0:355018f44c9f	1020	/* End of ACK for new data processing. */
dirkx	0:355018f44c9f	1021
dirkx	0:355018f44c9f	1022	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
dirkx	0:355018f44c9f	1023	pcb->rttest, pcb->rtseq, ackno));
dirkx	0:355018f44c9f	1024
dirkx	0:355018f44c9f	1025	/* RTT estimation calculations. This is done by checking if the
dirkx	0:355018f44c9f	1026	incoming segment acknowledges the segment we use to take a
dirkx	0:355018f44c9f	1027	round-trip time measurement. */
dirkx	0:355018f44c9f	1028	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
dirkx	0:355018f44c9f	1029	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
dirkx	0:355018f44c9f	1030	and a round-trip shouldn't be that long... */
dirkx	0:355018f44c9f	1031	m = (s16_t)(tcp_ticks - pcb->rttest);
dirkx	0:355018f44c9f	1032
dirkx	0:355018f44c9f	1033	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
dirkx	0:355018f44c9f	1034	m, m * TCP_SLOW_INTERVAL));
dirkx	0:355018f44c9f	1035
dirkx	0:355018f44c9f	1036	/* This is taken directly from VJs original code in his paper */
dirkx	0:355018f44c9f	1037	m = m - (pcb->sa >> 3);
dirkx	0:355018f44c9f	1038	pcb->sa += m;
dirkx	0:355018f44c9f	1039	if (m < 0) {
dirkx	0:355018f44c9f	1040	m = -m;
dirkx	0:355018f44c9f	1041	}
dirkx	0:355018f44c9f	1042	m = m - (pcb->sv >> 2);
dirkx	0:355018f44c9f	1043	pcb->sv += m;
dirkx	0:355018f44c9f	1044	pcb->rto = (pcb->sa >> 3) + pcb->sv;
dirkx	0:355018f44c9f	1045
dirkx	0:355018f44c9f	1046	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
dirkx	0:355018f44c9f	1047	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
dirkx	0:355018f44c9f	1048
dirkx	0:355018f44c9f	1049	pcb->rttest = 0;
dirkx	0:355018f44c9f	1050	}
dirkx	0:355018f44c9f	1051	}
dirkx	0:355018f44c9f	1052
dirkx	0:355018f44c9f	1053	/* If the incoming segment contains data, we must process it
dirkx	0:355018f44c9f	1054	further. */
dirkx	0:355018f44c9f	1055	if (tcplen > 0) {
dirkx	0:355018f44c9f	1056	/* This code basically does three things:
dirkx	0:355018f44c9f	1057
dirkx	0:355018f44c9f	1058	+) If the incoming segment contains data that is the next
dirkx	0:355018f44c9f	1059	in-sequence data, this data is passed to the application. This
dirkx	0:355018f44c9f	1060	might involve trimming the first edge of the data. The rcv_nxt
dirkx	0:355018f44c9f	1061	variable and the advertised window are adjusted.
dirkx	0:355018f44c9f	1062
dirkx	0:355018f44c9f	1063	+) If the incoming segment has data that is above the next
dirkx	0:355018f44c9f	1064	sequence number expected (->rcv_nxt), the segment is placed on
dirkx	0:355018f44c9f	1065	the ->ooseq queue. This is done by finding the appropriate
dirkx	0:355018f44c9f	1066	place in the ->ooseq queue (which is ordered by sequence
dirkx	0:355018f44c9f	1067	number) and trim the segment in both ends if needed. An
dirkx	0:355018f44c9f	1068	immediate ACK is sent to indicate that we received an
dirkx	0:355018f44c9f	1069	out-of-sequence segment.
dirkx	0:355018f44c9f	1070
dirkx	0:355018f44c9f	1071	+) Finally, we check if the first segment on the ->ooseq queue
dirkx	0:355018f44c9f	1072	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
dirkx	0:355018f44c9f	1073	rcv_nxt > ooseq->seqno, we must trim the first edge of the
dirkx	0:355018f44c9f	1074	segment on ->ooseq before we adjust rcv_nxt. The data in the
dirkx	0:355018f44c9f	1075	segments that are now on sequence are chained onto the
dirkx	0:355018f44c9f	1076	incoming segment so that we only need to call the application
dirkx	0:355018f44c9f	1077	once.
dirkx	0:355018f44c9f	1078	*/
dirkx	0:355018f44c9f	1079
dirkx	0:355018f44c9f	1080	/* First, we check if we must trim the first edge. We have to do
dirkx	0:355018f44c9f	1081	this if the sequence number of the incoming segment is less
dirkx	0:355018f44c9f	1082	than rcv_nxt, and the sequence number plus the length of the
dirkx	0:355018f44c9f	1083	segment is larger than rcv_nxt. */
dirkx	0:355018f44c9f	1084	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
dirkx	0:355018f44c9f	1085	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
dirkx	0:355018f44c9f	1086	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
dirkx	0:355018f44c9f	1087	/* Trimming the first edge is done by pushing the payload
dirkx	0:355018f44c9f	1088	pointer in the pbuf downwards. This is somewhat tricky since
dirkx	0:355018f44c9f	1089	we do not want to discard the full contents of the pbuf up to
dirkx	0:355018f44c9f	1090	the new starting point of the data since we have to keep the
dirkx	0:355018f44c9f	1091	TCP header which is present in the first pbuf in the chain.
dirkx	0:355018f44c9f	1092
dirkx	0:355018f44c9f	1093	What is done is really quite a nasty hack: the first pbuf in
dirkx	0:355018f44c9f	1094	the pbuf chain is pointed to by inseg.p. Since we need to be
dirkx	0:355018f44c9f	1095	able to deallocate the whole pbuf, we cannot change this
dirkx	0:355018f44c9f	1096	inseg.p pointer to point to any of the later pbufs in the
dirkx	0:355018f44c9f	1097	chain. Instead, we point the ->payload pointer in the first
dirkx	0:355018f44c9f	1098	pbuf to data in one of the later pbufs. We also set the
dirkx	0:355018f44c9f	1099	inseg.data pointer to point to the right place. This way, the
dirkx	0:355018f44c9f	1100	->p pointer will still point to the first pbuf, but the
dirkx	0:355018f44c9f	1101	->p->payload pointer will point to data in another pbuf.
dirkx	0:355018f44c9f	1102
dirkx	0:355018f44c9f	1103	After we are done with adjusting the pbuf pointers we must
dirkx	0:355018f44c9f	1104	adjust the ->data pointer in the seg and the segment
dirkx	0:355018f44c9f	1105	length.*/
dirkx	0:355018f44c9f	1106
dirkx	0:355018f44c9f	1107	off = pcb->rcv_nxt - seqno;
dirkx	0:355018f44c9f	1108	p = inseg.p;
dirkx	0:355018f44c9f	1109	LWIP_ASSERT("inseg.p != NULL", inseg.p);
dirkx	0:355018f44c9f	1110	LWIP_ASSERT("insane offset!", (off < 0x7fff));
dirkx	0:355018f44c9f	1111	if (inseg.p->len < off) {
dirkx	0:355018f44c9f	1112	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
dirkx	0:355018f44c9f	1113	new_tot_len = (u16_t)(inseg.p->tot_len - off);
dirkx	0:355018f44c9f	1114	while (p->len < off) {
dirkx	0:355018f44c9f	1115	off -= p->len;
dirkx	0:355018f44c9f	1116	/* KJM following line changed (with addition of new_tot_len var)
dirkx	0:355018f44c9f	1117	to fix bug #9076
dirkx	0:355018f44c9f	1118	inseg.p->tot_len -= p->len; */
dirkx	0:355018f44c9f	1119	p->tot_len = new_tot_len;
dirkx	0:355018f44c9f	1120	p->len = 0;
dirkx	0:355018f44c9f	1121	p = p->next;
dirkx	0:355018f44c9f	1122	}
dirkx	0:355018f44c9f	1123	if(pbuf_header(p, (s16_t)-off)) {
dirkx	0:355018f44c9f	1124	/* Do we need to cope with this failing? Assert for now */
dirkx	0:355018f44c9f	1125	LWIP_ASSERT("pbuf_header failed", 0);
dirkx	0:355018f44c9f	1126	}
dirkx	0:355018f44c9f	1127	} else {
dirkx	0:355018f44c9f	1128	if(pbuf_header(inseg.p, (s16_t)-off)) {
dirkx	0:355018f44c9f	1129	/* Do we need to cope with this failing? Assert for now */
dirkx	0:355018f44c9f	1130	LWIP_ASSERT("pbuf_header failed", 0);
dirkx	0:355018f44c9f	1131	}
dirkx	0:355018f44c9f	1132	}
dirkx	0:355018f44c9f	1133	/* KJM following line changed to use p->payload rather than inseg->p->payload
dirkx	0:355018f44c9f	1134	to fix bug #9076 */
dirkx	0:355018f44c9f	1135	inseg.dataptr = p->payload;
dirkx	0:355018f44c9f	1136	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
dirkx	0:355018f44c9f	1137	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
dirkx	0:355018f44c9f	1138	}
dirkx	0:355018f44c9f	1139	else {
dirkx	0:355018f44c9f	1140	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
dirkx	0:355018f44c9f	1141	/* the whole segment is < rcv_nxt */
dirkx	0:355018f44c9f	1142	/* must be a duplicate of a packet that has already been correctly handled */
dirkx	0:355018f44c9f	1143
dirkx	0:355018f44c9f	1144	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
dirkx	0:355018f44c9f	1145	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	1146	}
dirkx	0:355018f44c9f	1147	}
dirkx	0:355018f44c9f	1148
dirkx	0:355018f44c9f	1149	/* The sequence number must be within the window (above rcv_nxt
dirkx	0:355018f44c9f	1150	and below rcv_nxt + rcv_wnd) in order to be further
dirkx	0:355018f44c9f	1151	processed. */
dirkx	0:355018f44c9f	1152	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
dirkx	0:355018f44c9f	1153	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
dirkx	0:355018f44c9f	1154	if (pcb->rcv_nxt == seqno) {
dirkx	0:355018f44c9f	1155	/* The incoming segment is the next in sequence. We check if
dirkx	0:355018f44c9f	1156	we have to trim the end of the segment and update rcv_nxt
dirkx	0:355018f44c9f	1157	and pass the data to the application. */
dirkx	0:355018f44c9f	1158	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:355018f44c9f	1159
dirkx	0:355018f44c9f	1160	if (tcplen > pcb->rcv_wnd) {
dirkx	0:355018f44c9f	1161	LWIP_DEBUGF(TCP_INPUT_DEBUG,
dirkx	0:355018f44c9f	1162	("tcp_receive: other end overran receive window"
dirkx	0:355018f44c9f	1163	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
dirkx	0:355018f44c9f	1164	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
dirkx	0:355018f44c9f	1165	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	1166	/* Must remove the FIN from the header as we're trimming
dirkx	0:355018f44c9f	1167	* that byte of sequence-space from the packet */
dirkx	0:355018f44c9f	1168	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
dirkx	0:355018f44c9f	1169	}
dirkx	0:355018f44c9f	1170	/* Adjust length of segment to fit in the window. */
dirkx	0:355018f44c9f	1171	inseg.len = pcb->rcv_wnd;
dirkx	0:355018f44c9f	1172	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
dirkx	0:355018f44c9f	1173	inseg.len -= 1;
dirkx	0:355018f44c9f	1174	}
dirkx	0:355018f44c9f	1175	pbuf_realloc(inseg.p, inseg.len);
dirkx	0:355018f44c9f	1176	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:355018f44c9f	1177	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
dirkx	0:355018f44c9f	1178	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
dirkx	0:355018f44c9f	1179	}
dirkx	0:355018f44c9f	1180	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	1181	/* Received in-sequence data, adjust ooseq data if:
dirkx	0:355018f44c9f	1182	- FIN has been received or
dirkx	0:355018f44c9f	1183	- inseq overlaps with ooseq */
dirkx	0:355018f44c9f	1184	if (pcb->ooseq != NULL) {
dirkx	0:355018f44c9f	1185	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	1186	LWIP_DEBUGF(TCP_INPUT_DEBUG,
dirkx	0:355018f44c9f	1187	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
dirkx	0:355018f44c9f	1188	/* Received in-order FIN means anything that was received
dirkx	0:355018f44c9f	1189	* out of order must now have been received in-order, so
dirkx	0:355018f44c9f	1190	* bin the ooseq queue */
dirkx	0:355018f44c9f	1191	while (pcb->ooseq != NULL) {
dirkx	0:355018f44c9f	1192	struct tcp_seg *old_ooseq = pcb->ooseq;
dirkx	0:355018f44c9f	1193	pcb->ooseq = pcb->ooseq->next;
dirkx	0:355018f44c9f	1194	tcp_seg_free(old_ooseq);
dirkx	0:355018f44c9f	1195	}
dirkx	0:355018f44c9f	1196	}
dirkx	0:355018f44c9f	1197	else {
dirkx	0:355018f44c9f	1198	next = pcb->ooseq;
dirkx	0:355018f44c9f	1199	/* Remove all segments on ooseq that are covered by inseg already.
dirkx	0:355018f44c9f	1200	* FIN is copied from ooseq to inseg if present. */
dirkx	0:355018f44c9f	1201	while (next &&
dirkx	0:355018f44c9f	1202	TCP_SEQ_GEQ(seqno + tcplen,
dirkx	0:355018f44c9f	1203	next->tcphdr->seqno + next->len)) {
dirkx	0:355018f44c9f	1204	/* inseg cannot have FIN here (already processed above) */
dirkx	0:355018f44c9f	1205	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
dirkx	0:355018f44c9f	1206	(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
dirkx	0:355018f44c9f	1207	TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
dirkx	0:355018f44c9f	1208	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:355018f44c9f	1209	}
dirkx	0:355018f44c9f	1210	prev = next;
dirkx	0:355018f44c9f	1211	next = next->next;
dirkx	0:355018f44c9f	1212	tcp_seg_free(prev);
dirkx	0:355018f44c9f	1213	}
dirkx	0:355018f44c9f	1214	/* Now trim right side of inseg if it overlaps with the first
dirkx	0:355018f44c9f	1215	* segment on ooseq */
dirkx	0:355018f44c9f	1216	if (next &&
dirkx	0:355018f44c9f	1217	TCP_SEQ_GT(seqno + tcplen,
dirkx	0:355018f44c9f	1218	next->tcphdr->seqno)) {
dirkx	0:355018f44c9f	1219	/* inseg cannot have FIN here (already processed above) */
dirkx	0:355018f44c9f	1220	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
dirkx	0:355018f44c9f	1221	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
dirkx	0:355018f44c9f	1222	inseg.len -= 1;
dirkx	0:355018f44c9f	1223	}
dirkx	0:355018f44c9f	1224	pbuf_realloc(inseg.p, inseg.len);
dirkx	0:355018f44c9f	1225	tcplen = TCP_TCPLEN(&inseg);
dirkx	0:355018f44c9f	1226	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
dirkx	0:355018f44c9f	1227	(seqno + tcplen) == next->tcphdr->seqno);
dirkx	0:355018f44c9f	1228	}
dirkx	0:355018f44c9f	1229	pcb->ooseq = next;
dirkx	0:355018f44c9f	1230	}
dirkx	0:355018f44c9f	1231	}
dirkx	0:355018f44c9f	1232	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:355018f44c9f	1233
dirkx	0:355018f44c9f	1234	pcb->rcv_nxt = seqno + tcplen;
dirkx	0:355018f44c9f	1235
dirkx	0:355018f44c9f	1236	/* Update the receiver's (our) window. */
dirkx	0:355018f44c9f	1237	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
dirkx	0:355018f44c9f	1238	pcb->rcv_wnd -= tcplen;
dirkx	0:355018f44c9f	1239
dirkx	0:355018f44c9f	1240	tcp_update_rcv_ann_wnd(pcb);
dirkx	0:355018f44c9f	1241
dirkx	0:355018f44c9f	1242	/* If there is data in the segment, we make preparations to
dirkx	0:355018f44c9f	1243	pass this up to the application. The ->recv_data variable
dirkx	0:355018f44c9f	1244	is used for holding the pbuf that goes to the
dirkx	0:355018f44c9f	1245	application. The code for reassembling out-of-sequence data
dirkx	0:355018f44c9f	1246	chains its data on this pbuf as well.
dirkx	0:355018f44c9f	1247
dirkx	0:355018f44c9f	1248	If the segment was a FIN, we set the TF_GOT_FIN flag that will
dirkx	0:355018f44c9f	1249	be used to indicate to the application that the remote side has
dirkx	0:355018f44c9f	1250	closed its end of the connection. */
dirkx	0:355018f44c9f	1251	if (inseg.p->tot_len > 0) {
dirkx	0:355018f44c9f	1252	recv_data = inseg.p;
dirkx	0:355018f44c9f	1253	/* Since this pbuf now is the responsibility of the
dirkx	0:355018f44c9f	1254	application, we delete our reference to it so that we won't
dirkx	0:355018f44c9f	1255	(mistakingly) deallocate it. */
dirkx	0:355018f44c9f	1256	inseg.p = NULL;
dirkx	0:355018f44c9f	1257	}
dirkx	0:355018f44c9f	1258	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	1259	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
dirkx	0:355018f44c9f	1260	recv_flags \|= TF_GOT_FIN;
dirkx	0:355018f44c9f	1261	}
dirkx	0:355018f44c9f	1262
dirkx	0:355018f44c9f	1263	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	1264	/* We now check if we have segments on the ->ooseq queue that
dirkx	0:355018f44c9f	1265	are now in sequence. */
dirkx	0:355018f44c9f	1266	while (pcb->ooseq != NULL &&
dirkx	0:355018f44c9f	1267	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
dirkx	0:355018f44c9f	1268
dirkx	0:355018f44c9f	1269	cseg = pcb->ooseq;
dirkx	0:355018f44c9f	1270	seqno = pcb->ooseq->tcphdr->seqno;
dirkx	0:355018f44c9f	1271
dirkx	0:355018f44c9f	1272	pcb->rcv_nxt += TCP_TCPLEN(cseg);
dirkx	0:355018f44c9f	1273	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
dirkx	0:355018f44c9f	1274	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
dirkx	0:355018f44c9f	1275	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
dirkx	0:355018f44c9f	1276
dirkx	0:355018f44c9f	1277	tcp_update_rcv_ann_wnd(pcb);
dirkx	0:355018f44c9f	1278
dirkx	0:355018f44c9f	1279	if (cseg->p->tot_len > 0) {
dirkx	0:355018f44c9f	1280	/* Chain this pbuf onto the pbuf that we will pass to
dirkx	0:355018f44c9f	1281	the application. */
dirkx	0:355018f44c9f	1282	if (recv_data) {
dirkx	0:355018f44c9f	1283	pbuf_cat(recv_data, cseg->p);
dirkx	0:355018f44c9f	1284	} else {
dirkx	0:355018f44c9f	1285	recv_data = cseg->p;
dirkx	0:355018f44c9f	1286	}
dirkx	0:355018f44c9f	1287	cseg->p = NULL;
dirkx	0:355018f44c9f	1288	}
dirkx	0:355018f44c9f	1289	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	1290	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
dirkx	0:355018f44c9f	1291	recv_flags \|= TF_GOT_FIN;
dirkx	0:355018f44c9f	1292	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
dirkx	0:355018f44c9f	1293	pcb->state = CLOSE_WAIT;
dirkx	0:355018f44c9f	1294	}
dirkx	0:355018f44c9f	1295	}
dirkx	0:355018f44c9f	1296
dirkx	0:355018f44c9f	1297	pcb->ooseq = cseg->next;
dirkx	0:355018f44c9f	1298	tcp_seg_free(cseg);
dirkx	0:355018f44c9f	1299	}
dirkx	0:355018f44c9f	1300	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:355018f44c9f	1301
dirkx	0:355018f44c9f	1302
dirkx	0:355018f44c9f	1303	/* Acknowledge the segment(s). */
dirkx	0:355018f44c9f	1304	tcp_ack(pcb);
dirkx	0:355018f44c9f	1305
dirkx	0:355018f44c9f	1306	} else {
dirkx	0:355018f44c9f	1307	/* We get here if the incoming segment is out-of-sequence. */
dirkx	0:355018f44c9f	1308	tcp_send_empty_ack(pcb);
dirkx	0:355018f44c9f	1309	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	1310	/* We queue the segment on the ->ooseq queue. */
dirkx	0:355018f44c9f	1311	if (pcb->ooseq == NULL) {
dirkx	0:355018f44c9f	1312	pcb->ooseq = tcp_seg_copy(&inseg);
dirkx	0:355018f44c9f	1313	} else {
dirkx	0:355018f44c9f	1314	/* If the queue is not empty, we walk through the queue and
dirkx	0:355018f44c9f	1315	try to find a place where the sequence number of the
dirkx	0:355018f44c9f	1316	incoming segment is between the sequence numbers of the
dirkx	0:355018f44c9f	1317	previous and the next segment on the ->ooseq queue. That is
dirkx	0:355018f44c9f	1318	the place where we put the incoming segment. If needed, we
dirkx	0:355018f44c9f	1319	trim the second edges of the previous and the incoming
dirkx	0:355018f44c9f	1320	segment so that it will fit into the sequence.
dirkx	0:355018f44c9f	1321
dirkx	0:355018f44c9f	1322	If the incoming segment has the same sequence number as a
dirkx	0:355018f44c9f	1323	segment on the ->ooseq queue, we discard the segment that
dirkx	0:355018f44c9f	1324	contains less data. */
dirkx	0:355018f44c9f	1325
dirkx	0:355018f44c9f	1326	prev = NULL;
dirkx	0:355018f44c9f	1327	for(next = pcb->ooseq; next != NULL; next = next->next) {
dirkx	0:355018f44c9f	1328	if (seqno == next->tcphdr->seqno) {
dirkx	0:355018f44c9f	1329	/* The sequence number of the incoming segment is the
dirkx	0:355018f44c9f	1330	same as the sequence number of the segment on
dirkx	0:355018f44c9f	1331	->ooseq. We check the lengths to see which one to
dirkx	0:355018f44c9f	1332	discard. */
dirkx	0:355018f44c9f	1333	if (inseg.len > next->len) {
dirkx	0:355018f44c9f	1334	/* The incoming segment is larger than the old
dirkx	0:355018f44c9f	1335	segment. We replace some segments with the new
dirkx	0:355018f44c9f	1336	one. */
dirkx	0:355018f44c9f	1337	cseg = tcp_seg_copy(&inseg);
dirkx	0:355018f44c9f	1338	if (cseg != NULL) {
dirkx	0:355018f44c9f	1339	if (prev != NULL) {
dirkx	0:355018f44c9f	1340	prev->next = cseg;
dirkx	0:355018f44c9f	1341	} else {
dirkx	0:355018f44c9f	1342	pcb->ooseq = cseg;
dirkx	0:355018f44c9f	1343	}
dirkx	0:355018f44c9f	1344	tcp_oos_insert_segment(cseg, next);
dirkx	0:355018f44c9f	1345	}
dirkx	0:355018f44c9f	1346	break;
dirkx	0:355018f44c9f	1347	} else {
dirkx	0:355018f44c9f	1348	/* Either the lenghts are the same or the incoming
dirkx	0:355018f44c9f	1349	segment was smaller than the old one; in either
dirkx	0:355018f44c9f	1350	case, we ditch the incoming segment. */
dirkx	0:355018f44c9f	1351	break;
dirkx	0:355018f44c9f	1352	}
dirkx	0:355018f44c9f	1353	} else {
dirkx	0:355018f44c9f	1354	if (prev == NULL) {
dirkx	0:355018f44c9f	1355	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
dirkx	0:355018f44c9f	1356	/* The sequence number of the incoming segment is lower
dirkx	0:355018f44c9f	1357	than the sequence number of the first segment on the
dirkx	0:355018f44c9f	1358	queue. We put the incoming segment first on the
dirkx	0:355018f44c9f	1359	queue. */
dirkx	0:355018f44c9f	1360	cseg = tcp_seg_copy(&inseg);
dirkx	0:355018f44c9f	1361	if (cseg != NULL) {
dirkx	0:355018f44c9f	1362	pcb->ooseq = cseg;
dirkx	0:355018f44c9f	1363	tcp_oos_insert_segment(cseg, next);
dirkx	0:355018f44c9f	1364	}
dirkx	0:355018f44c9f	1365	break;
dirkx	0:355018f44c9f	1366	}
dirkx	0:355018f44c9f	1367	} else {
dirkx	0:355018f44c9f	1368	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
dirkx	0:355018f44c9f	1369	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
dirkx	0:355018f44c9f	1370	if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
dirkx	0:355018f44c9f	1371	/* The sequence number of the incoming segment is in
dirkx	0:355018f44c9f	1372	between the sequence numbers of the previous and
dirkx	0:355018f44c9f	1373	the next segment on ->ooseq. We trim trim the previous
dirkx	0:355018f44c9f	1374	segment, delete next segments that included in received segment
dirkx	0:355018f44c9f	1375	and trim received, if needed. */
dirkx	0:355018f44c9f	1376	cseg = tcp_seg_copy(&inseg);
dirkx	0:355018f44c9f	1377	if (cseg != NULL) {
dirkx	0:355018f44c9f	1378	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
dirkx	0:355018f44c9f	1379	/* We need to trim the prev segment. */
dirkx	0:355018f44c9f	1380	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
dirkx	0:355018f44c9f	1381	pbuf_realloc(prev->p, prev->len);
dirkx	0:355018f44c9f	1382	}
dirkx	0:355018f44c9f	1383	prev->next = cseg;
dirkx	0:355018f44c9f	1384	tcp_oos_insert_segment(cseg, next);
dirkx	0:355018f44c9f	1385	}
dirkx	0:355018f44c9f	1386	break;
dirkx	0:355018f44c9f	1387	}
dirkx	0:355018f44c9f	1388	}
dirkx	0:355018f44c9f	1389	/* If the "next" segment is the last segment on the
dirkx	0:355018f44c9f	1390	ooseq queue, we add the incoming segment to the end
dirkx	0:355018f44c9f	1391	of the list. */
dirkx	0:355018f44c9f	1392	if (next->next == NULL &&
dirkx	0:355018f44c9f	1393	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
dirkx	0:355018f44c9f	1394	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
dirkx	0:355018f44c9f	1395	/* segment "next" already contains all data */
dirkx	0:355018f44c9f	1396	break;
dirkx	0:355018f44c9f	1397	}
dirkx	0:355018f44c9f	1398	next->next = tcp_seg_copy(&inseg);
dirkx	0:355018f44c9f	1399	if (next->next != NULL) {
dirkx	0:355018f44c9f	1400	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
dirkx	0:355018f44c9f	1401	/* We need to trim the last segment. */
dirkx	0:355018f44c9f	1402	next->len = (u16_t)(seqno - next->tcphdr->seqno);
dirkx	0:355018f44c9f	1403	pbuf_realloc(next->p, next->len);
dirkx	0:355018f44c9f	1404	}
dirkx	0:355018f44c9f	1405	}
dirkx	0:355018f44c9f	1406	break;
dirkx	0:355018f44c9f	1407	}
dirkx	0:355018f44c9f	1408	}
dirkx	0:355018f44c9f	1409	prev = next;
dirkx	0:355018f44c9f	1410	}
dirkx	0:355018f44c9f	1411	}
dirkx	0:355018f44c9f	1412	#endif /* TCP_QUEUE_OOSEQ */
dirkx	0:355018f44c9f	1413
dirkx	0:355018f44c9f	1414	}
dirkx	0:355018f44c9f	1415	} else {
dirkx	0:355018f44c9f	1416	/* The incoming segment is not withing the window. */
dirkx	0:355018f44c9f	1417	tcp_send_empty_ack(pcb);
dirkx	0:355018f44c9f	1418	}
dirkx	0:355018f44c9f	1419	} else {
dirkx	0:355018f44c9f	1420	/* Segments with length 0 is taken care of here. Segments that
dirkx	0:355018f44c9f	1421	fall out of the window are ACKed. */
dirkx	0:355018f44c9f	1422	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
dirkx	0:355018f44c9f	1423	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
dirkx	0:355018f44c9f	1424	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
dirkx	0:355018f44c9f	1425	tcp_ack_now(pcb);
dirkx	0:355018f44c9f	1426	}
dirkx	0:355018f44c9f	1427	}
dirkx	0:355018f44c9f	1428	}
dirkx	0:355018f44c9f	1429
dirkx	0:355018f44c9f	1430	/**
dirkx	0:355018f44c9f	1431	* Parses the options contained in the incoming segment.
dirkx	0:355018f44c9f	1432	*
dirkx	0:355018f44c9f	1433	* Called from tcp_listen_input() and tcp_process().
dirkx	0:355018f44c9f	1434	* Currently, only the MSS option is supported!
dirkx	0:355018f44c9f	1435	*
dirkx	0:355018f44c9f	1436	* @param pcb the tcp_pcb for which a segment arrived
dirkx	0:355018f44c9f	1437	*/
dirkx	0:355018f44c9f	1438	static void
dirkx	0:355018f44c9f	1439	tcp_parseopt(struct tcp_pcb *pcb)
dirkx	0:355018f44c9f	1440	{
dirkx	0:355018f44c9f	1441	u16_t c, max_c;
dirkx	0:355018f44c9f	1442	u16_t mss;
dirkx	0:355018f44c9f	1443	u8_t *opts, opt;
dirkx	0:355018f44c9f	1444	#if LWIP_TCP_TIMESTAMPS
dirkx	0:355018f44c9f	1445	u32_t tsval;
dirkx	0:355018f44c9f	1446	#endif
dirkx	0:355018f44c9f	1447
dirkx	0:355018f44c9f	1448	opts = (u8_t *)tcphdr + TCP_HLEN;
dirkx	0:355018f44c9f	1449
dirkx	0:355018f44c9f	1450	/* Parse the TCP MSS option, if present. */
dirkx	0:355018f44c9f	1451	if(TCPH_HDRLEN(tcphdr) > 0x5) {
dirkx	0:355018f44c9f	1452	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
dirkx	0:355018f44c9f	1453	for (c = 0; c < max_c; ) {
dirkx	0:355018f44c9f	1454	opt = opts[c];
dirkx	0:355018f44c9f	1455	switch (opt) {
dirkx	0:355018f44c9f	1456	case 0x00:
dirkx	0:355018f44c9f	1457	/* End of options. */
dirkx	0:355018f44c9f	1458	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
dirkx	0:355018f44c9f	1459	return;
dirkx	0:355018f44c9f	1460	case 0x01:
dirkx	0:355018f44c9f	1461	/* NOP option. */
dirkx	0:355018f44c9f	1462	++c;
dirkx	0:355018f44c9f	1463	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
dirkx	0:355018f44c9f	1464	break;
dirkx	0:355018f44c9f	1465	case 0x02:
dirkx	0:355018f44c9f	1466	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
dirkx	0:355018f44c9f	1467	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
dirkx	0:355018f44c9f	1468	/* Bad length */
dirkx	0:355018f44c9f	1469	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:355018f44c9f	1470	return;
dirkx	0:355018f44c9f	1471	}
dirkx	0:355018f44c9f	1472	/* An MSS option with the right option length. */
dirkx	0:355018f44c9f	1473	mss = (opts[c + 2] << 8) \| opts[c + 3];
dirkx	0:355018f44c9f	1474	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
dirkx	0:355018f44c9f	1475	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
dirkx	0:355018f44c9f	1476	/* Advance to next option */
dirkx	0:355018f44c9f	1477	c += 0x04;
dirkx	0:355018f44c9f	1478	break;
dirkx	0:355018f44c9f	1479	#if LWIP_TCP_TIMESTAMPS
dirkx	0:355018f44c9f	1480	case 0x08:
dirkx	0:355018f44c9f	1481	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
dirkx	0:355018f44c9f	1482	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
dirkx	0:355018f44c9f	1483	/* Bad length */
dirkx	0:355018f44c9f	1484	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:355018f44c9f	1485	return;
dirkx	0:355018f44c9f	1486	}
dirkx	0:355018f44c9f	1487	/* TCP timestamp option with valid length */
dirkx	0:355018f44c9f	1488	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
dirkx	0:355018f44c9f	1489	(opts[c+4] << 16) \| (opts[c+5] << 24);
dirkx	0:355018f44c9f	1490	if (flags & TCP_SYN) {
dirkx	0:355018f44c9f	1491	pcb->ts_recent = ntohl(tsval);
dirkx	0:355018f44c9f	1492	pcb->flags \|= TF_TIMESTAMP;
dirkx	0:355018f44c9f	1493	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
dirkx	0:355018f44c9f	1494	pcb->ts_recent = ntohl(tsval);
dirkx	0:355018f44c9f	1495	}
dirkx	0:355018f44c9f	1496	/* Advance to next option */
dirkx	0:355018f44c9f	1497	c += 0x0A;
dirkx	0:355018f44c9f	1498	break;
dirkx	0:355018f44c9f	1499	#endif
dirkx	0:355018f44c9f	1500	default:
dirkx	0:355018f44c9f	1501	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
dirkx	0:355018f44c9f	1502	if (opts[c + 1] == 0) {
dirkx	0:355018f44c9f	1503	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
dirkx	0:355018f44c9f	1504	/* If the length field is zero, the options are malformed
dirkx	0:355018f44c9f	1505	and we don't process them further. */
dirkx	0:355018f44c9f	1506	return;
dirkx	0:355018f44c9f	1507	}
dirkx	0:355018f44c9f	1508	/* All other options have a length field, so that we easily
dirkx	0:355018f44c9f	1509	can skip past them. */
dirkx	0:355018f44c9f	1510	c += opts[c + 1];
dirkx	0:355018f44c9f	1511	}
dirkx	0:355018f44c9f	1512	}
dirkx	0:355018f44c9f	1513	}
dirkx	0:355018f44c9f	1514	}
dirkx	0:355018f44c9f	1515
dirkx	0:355018f44c9f	1516	#endif /* LWIP_TCP */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	21 Jul 2010
Imports:	99
Forks:	0
Commits:	6
Dependents:	0
Dependencies:	1
Followers:	8

lwip/core/tcp_in.c@5:8e53abda9900, 2010-08-14 (annotated)

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