lwip-mbed-2010 - Port of LwIP performed by Ralf in 2010. Not recom…

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Rod Coleman / lwip-mbed-2010

Port of LwIP performed by Ralf in 2010. Not recommended for use with recent mbed libraries, but good demos of raw LwIP possible

Dependents: LwIP_raw_API_serverExample tiny-dtls

Core/lwIP/core/tcp_in.c@0:0791c1fece8e, 2012-09-18 (annotated)

Committer:: RodColeman
Date:: Tue Sep 18 14:41:24 2012 +0000
Revision:: 0:0791c1fece8e

[mbed] converted /Eth_TCP_Wei_Server/lwip

Who changed what in which revision?

User	Revision	Line number	New contents of line
RodColeman	0:0791c1fece8e	1	/**
RodColeman	0:0791c1fece8e	2	* @file
RodColeman	0:0791c1fece8e	3	* Transmission Control Protocol, incoming traffic
RodColeman	0:0791c1fece8e	4	*
RodColeman	0:0791c1fece8e	5	* The input processing functions of the TCP layer.
RodColeman	0:0791c1fece8e	6	*
RodColeman	0:0791c1fece8e	7	* These functions are generally called in the order (ip_input() ->)
RodColeman	0:0791c1fece8e	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
RodColeman	0:0791c1fece8e	9	*
RodColeman	0:0791c1fece8e	10	*/
RodColeman	0:0791c1fece8e	11
RodColeman	0:0791c1fece8e	12	/*
RodColeman	0:0791c1fece8e	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
RodColeman	0:0791c1fece8e	14	* All rights reserved.
RodColeman	0:0791c1fece8e	15	*
RodColeman	0:0791c1fece8e	16	* Redistribution and use in source and binary forms, with or without modification,
RodColeman	0:0791c1fece8e	17	* are permitted provided that the following conditions are met:
RodColeman	0:0791c1fece8e	18	*
RodColeman	0:0791c1fece8e	19	* 1. Redistributions of source code must retain the above copyright notice,
RodColeman	0:0791c1fece8e	20	* this list of conditions and the following disclaimer.
RodColeman	0:0791c1fece8e	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
RodColeman	0:0791c1fece8e	22	* this list of conditions and the following disclaimer in the documentation
RodColeman	0:0791c1fece8e	23	* and/or other materials provided with the distribution.
RodColeman	0:0791c1fece8e	24	* 3. The name of the author may not be used to endorse or promote products
RodColeman	0:0791c1fece8e	25	* derived from this software without specific prior written permission.
RodColeman	0:0791c1fece8e	26	*
RodColeman	0:0791c1fece8e	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
RodColeman	0:0791c1fece8e	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
RodColeman	0:0791c1fece8e	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
RodColeman	0:0791c1fece8e	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
RodColeman	0:0791c1fece8e	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
RodColeman	0:0791c1fece8e	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
RodColeman	0:0791c1fece8e	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
RodColeman	0:0791c1fece8e	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
RodColeman	0:0791c1fece8e	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
RodColeman	0:0791c1fece8e	36	* OF SUCH DAMAGE.
RodColeman	0:0791c1fece8e	37	*
RodColeman	0:0791c1fece8e	38	* This file is part of the lwIP TCP/IP stack.
RodColeman	0:0791c1fece8e	39	*
RodColeman	0:0791c1fece8e	40	* Author: Adam Dunkels <adam@sics.se>
RodColeman	0:0791c1fece8e	41	*
RodColeman	0:0791c1fece8e	42	*/
RodColeman	0:0791c1fece8e	43
RodColeman	0:0791c1fece8e	44	#include "lwip/opt.h"
RodColeman	0:0791c1fece8e	45
RodColeman	0:0791c1fece8e	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
RodColeman	0:0791c1fece8e	47
RodColeman	0:0791c1fece8e	48	#include "lwip/tcp.h"
RodColeman	0:0791c1fece8e	49	#include "lwip/def.h"
RodColeman	0:0791c1fece8e	50	#include "lwip/ip_addr.h"
RodColeman	0:0791c1fece8e	51	#include "lwip/netif.h"
RodColeman	0:0791c1fece8e	52	#include "lwip/mem.h"
RodColeman	0:0791c1fece8e	53	#include "lwip/memp.h"
RodColeman	0:0791c1fece8e	54	#include "lwip/inet.h"
RodColeman	0:0791c1fece8e	55	#include "lwip/inet_chksum.h"
RodColeman	0:0791c1fece8e	56	#include "lwip/stats.h"
RodColeman	0:0791c1fece8e	57	#include "lwip/snmp.h"
RodColeman	0:0791c1fece8e	58	#include "arch/perf.h"
RodColeman	0:0791c1fece8e	59
RodColeman	0:0791c1fece8e	60	/* These variables are global to all functions involved in the input
RodColeman	0:0791c1fece8e	61	processing of TCP segments. They are set by the tcp_input()
RodColeman	0:0791c1fece8e	62	function. */
RodColeman	0:0791c1fece8e	63	static struct tcp_seg inseg;
RodColeman	0:0791c1fece8e	64	static struct tcp_hdr *tcphdr;
RodColeman	0:0791c1fece8e	65	static struct ip_hdr *iphdr;
RodColeman	0:0791c1fece8e	66	static u32_t seqno, ackno;
RodColeman	0:0791c1fece8e	67	static u8_t flags;
RodColeman	0:0791c1fece8e	68	static u16_t tcplen;
RodColeman	0:0791c1fece8e	69
RodColeman	0:0791c1fece8e	70	static u8_t recv_flags;
RodColeman	0:0791c1fece8e	71	static struct pbuf *recv_data;
RodColeman	0:0791c1fece8e	72
RodColeman	0:0791c1fece8e	73	struct tcp_pcb *tcp_input_pcb;
RodColeman	0:0791c1fece8e	74
RodColeman	0:0791c1fece8e	75	/* Forward declarations. */
RodColeman	0:0791c1fece8e	76	static err_t tcp_process(struct tcp_pcb *pcb);
RodColeman	0:0791c1fece8e	77	static u8_t tcp_receive(struct tcp_pcb *pcb);
RodColeman	0:0791c1fece8e	78	static void tcp_parseopt(struct tcp_pcb *pcb);
RodColeman	0:0791c1fece8e	79
RodColeman	0:0791c1fece8e	80	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
RodColeman	0:0791c1fece8e	81	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
RodColeman	0:0791c1fece8e	82
RodColeman	0:0791c1fece8e	83	/**
RodColeman	0:0791c1fece8e	84	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
RodColeman	0:0791c1fece8e	85	* the segment between the PCBs and passes it on to tcp_process(), which implements
RodColeman	0:0791c1fece8e	86	* the TCP finite state machine. This function is called by the IP layer (in
RodColeman	0:0791c1fece8e	87	* ip_input()).
RodColeman	0:0791c1fece8e	88	*
RodColeman	0:0791c1fece8e	89	* @param p received TCP segment to process (p->payload pointing to the IP header)
RodColeman	0:0791c1fece8e	90	* @param inp network interface on which this segment was received
RodColeman	0:0791c1fece8e	91	*/
RodColeman	0:0791c1fece8e	92	void
RodColeman	0:0791c1fece8e	93	tcp_input(struct pbuf p, struct netif inp)
RodColeman	0:0791c1fece8e	94	{
RodColeman	0:0791c1fece8e	95	struct tcp_pcb pcb, prev;
RodColeman	0:0791c1fece8e	96	struct tcp_pcb_listen *lpcb;
RodColeman	0:0791c1fece8e	97	u8_t hdrlen;
RodColeman	0:0791c1fece8e	98	err_t err;
RodColeman	0:0791c1fece8e	99
RodColeman	0:0791c1fece8e	100	PERF_START;
RodColeman	0:0791c1fece8e	101
RodColeman	0:0791c1fece8e	102	TCP_STATS_INC(tcp.recv);
RodColeman	0:0791c1fece8e	103	snmp_inc_tcpinsegs();
RodColeman	0:0791c1fece8e	104
RodColeman	0:0791c1fece8e	105	iphdr = (struct ip_hdr *)p->payload;
RodColeman	0:0791c1fece8e	106	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
RodColeman	0:0791c1fece8e	107
RodColeman	0:0791c1fece8e	108	#if TCP_INPUT_DEBUG
RodColeman	0:0791c1fece8e	109	tcp_debug_print(tcphdr);
RodColeman	0:0791c1fece8e	110	#endif
RodColeman	0:0791c1fece8e	111
RodColeman	0:0791c1fece8e	112	/* remove header from payload */
RodColeman	0:0791c1fece8e	113	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
RodColeman	0:0791c1fece8e	114	/* drop short packets */
RodColeman	0:0791c1fece8e	115	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
RodColeman	0:0791c1fece8e	116	TCP_STATS_INC(tcp.lenerr);
RodColeman	0:0791c1fece8e	117	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	118	snmp_inc_tcpinerrs();
RodColeman	0:0791c1fece8e	119	pbuf_free(p);
RodColeman	0:0791c1fece8e	120	return;
RodColeman	0:0791c1fece8e	121	}
RodColeman	0:0791c1fece8e	122
RodColeman	0:0791c1fece8e	123	/* Don't even process incoming broadcasts/multicasts. */
RodColeman	0:0791c1fece8e	124	if (ip_addr_isbroadcast(&(iphdr->dest), inp) \|\|
RodColeman	0:0791c1fece8e	125	ip_addr_ismulticast(&(iphdr->dest))) {
RodColeman	0:0791c1fece8e	126	TCP_STATS_INC(tcp.proterr);
RodColeman	0:0791c1fece8e	127	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	128	snmp_inc_tcpinerrs();
RodColeman	0:0791c1fece8e	129	pbuf_free(p);
RodColeman	0:0791c1fece8e	130	return;
RodColeman	0:0791c1fece8e	131	}
RodColeman	0:0791c1fece8e	132
RodColeman	0:0791c1fece8e	133	#if CHECKSUM_CHECK_TCP
RodColeman	0:0791c1fece8e	134	/* Verify TCP checksum. */
RodColeman	0:0791c1fece8e	135	if (inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
RodColeman	0:0791c1fece8e	136	(struct ip_addr *)&(iphdr->dest),
RodColeman	0:0791c1fece8e	137	IP_PROTO_TCP, p->tot_len) != 0) {
RodColeman	0:0791c1fece8e	138	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
RodColeman	0:0791c1fece8e	139	inet_chksum_pseudo(p, (struct ip_addr )&(iphdr->src), (struct ip_addr )&(iphdr->dest),
RodColeman	0:0791c1fece8e	140	IP_PROTO_TCP, p->tot_len)));
RodColeman	0:0791c1fece8e	141	#if TCP_DEBUG
RodColeman	0:0791c1fece8e	142	tcp_debug_print(tcphdr);
RodColeman	0:0791c1fece8e	143	#endif /* TCP_DEBUG */
RodColeman	0:0791c1fece8e	144	TCP_STATS_INC(tcp.chkerr);
RodColeman	0:0791c1fece8e	145	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	146	snmp_inc_tcpinerrs();
RodColeman	0:0791c1fece8e	147	pbuf_free(p);
RodColeman	0:0791c1fece8e	148	return;
RodColeman	0:0791c1fece8e	149	}
RodColeman	0:0791c1fece8e	150	#endif
RodColeman	0:0791c1fece8e	151
RodColeman	0:0791c1fece8e	152	/* Move the payload pointer in the pbuf so that it points to the
RodColeman	0:0791c1fece8e	153	TCP data instead of the TCP header. */
RodColeman	0:0791c1fece8e	154	hdrlen = TCPH_HDRLEN(tcphdr);
RodColeman	0:0791c1fece8e	155	if(pbuf_header(p, -(hdrlen * 4))){
RodColeman	0:0791c1fece8e	156	/* drop short packets */
RodColeman	0:0791c1fece8e	157	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
RodColeman	0:0791c1fece8e	158	TCP_STATS_INC(tcp.lenerr);
RodColeman	0:0791c1fece8e	159	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	160	snmp_inc_tcpinerrs();
RodColeman	0:0791c1fece8e	161	pbuf_free(p);
RodColeman	0:0791c1fece8e	162	return;
RodColeman	0:0791c1fece8e	163	}
RodColeman	0:0791c1fece8e	164
RodColeman	0:0791c1fece8e	165	/* Convert fields in TCP header to host byte order. */
RodColeman	0:0791c1fece8e	166	tcphdr->src = ntohs(tcphdr->src);
RodColeman	0:0791c1fece8e	167	tcphdr->dest = ntohs(tcphdr->dest);
RodColeman	0:0791c1fece8e	168	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
RodColeman	0:0791c1fece8e	169	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
RodColeman	0:0791c1fece8e	170	tcphdr->wnd = ntohs(tcphdr->wnd);
RodColeman	0:0791c1fece8e	171
RodColeman	0:0791c1fece8e	172	flags = TCPH_FLAGS(tcphdr);
RodColeman	0:0791c1fece8e	173	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
RodColeman	0:0791c1fece8e	174
RodColeman	0:0791c1fece8e	175	/* Demultiplex an incoming segment. First, we check if it is destined
RodColeman	0:0791c1fece8e	176	for an active connection. */
RodColeman	0:0791c1fece8e	177	prev = NULL;
RodColeman	0:0791c1fece8e	178
RodColeman	0:0791c1fece8e	179
RodColeman	0:0791c1fece8e	180	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
RodColeman	0:0791c1fece8e	181	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
RodColeman	0:0791c1fece8e	182	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
RodColeman	0:0791c1fece8e	183	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
RodColeman	0:0791c1fece8e	184	if (pcb->remote_port == tcphdr->src &&
RodColeman	0:0791c1fece8e	185	pcb->local_port == tcphdr->dest &&
RodColeman	0:0791c1fece8e	186	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
RodColeman	0:0791c1fece8e	187	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
RodColeman	0:0791c1fece8e	188
RodColeman	0:0791c1fece8e	189	/* Move this PCB to the front of the list so that subsequent
RodColeman	0:0791c1fece8e	190	lookups will be faster (we exploit locality in TCP segment
RodColeman	0:0791c1fece8e	191	arrivals). */
RodColeman	0:0791c1fece8e	192	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
RodColeman	0:0791c1fece8e	193	if (prev != NULL) {
RodColeman	0:0791c1fece8e	194	prev->next = pcb->next;
RodColeman	0:0791c1fece8e	195	pcb->next = tcp_active_pcbs;
RodColeman	0:0791c1fece8e	196	tcp_active_pcbs = pcb;
RodColeman	0:0791c1fece8e	197	}
RodColeman	0:0791c1fece8e	198	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
RodColeman	0:0791c1fece8e	199	break;
RodColeman	0:0791c1fece8e	200	}
RodColeman	0:0791c1fece8e	201	prev = pcb;
RodColeman	0:0791c1fece8e	202	}
RodColeman	0:0791c1fece8e	203
RodColeman	0:0791c1fece8e	204	if (pcb == NULL) {
RodColeman	0:0791c1fece8e	205	/* If it did not go to an active connection, we check the connections
RodColeman	0:0791c1fece8e	206	in the TIME-WAIT state. */
RodColeman	0:0791c1fece8e	207	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
RodColeman	0:0791c1fece8e	208	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
RodColeman	0:0791c1fece8e	209	if (pcb->remote_port == tcphdr->src &&
RodColeman	0:0791c1fece8e	210	pcb->local_port == tcphdr->dest &&
RodColeman	0:0791c1fece8e	211	ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) &&
RodColeman	0:0791c1fece8e	212	ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) {
RodColeman	0:0791c1fece8e	213	/* We don't really care enough to move this PCB to the front
RodColeman	0:0791c1fece8e	214	of the list since we are not very likely to receive that
RodColeman	0:0791c1fece8e	215	many segments for connections in TIME-WAIT. */
RodColeman	0:0791c1fece8e	216	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
RodColeman	0:0791c1fece8e	217	tcp_timewait_input(pcb);
RodColeman	0:0791c1fece8e	218	pbuf_free(p);
RodColeman	0:0791c1fece8e	219	return;
RodColeman	0:0791c1fece8e	220	}
RodColeman	0:0791c1fece8e	221	}
RodColeman	0:0791c1fece8e	222
RodColeman	0:0791c1fece8e	223	/* Finally, if we still did not get a match, we check all PCBs that
RodColeman	0:0791c1fece8e	224	are LISTENing for incoming connections. */
RodColeman	0:0791c1fece8e	225	prev = NULL;
RodColeman	0:0791c1fece8e	226	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
RodColeman	0:0791c1fece8e	227	if ((ip_addr_isany(&(lpcb->local_ip)) \|\|
RodColeman	0:0791c1fece8e	228	ip_addr_cmp(&(lpcb->local_ip), &(iphdr->dest))) &&
RodColeman	0:0791c1fece8e	229	lpcb->local_port == tcphdr->dest) {
RodColeman	0:0791c1fece8e	230	/* Move this PCB to the front of the list so that subsequent
RodColeman	0:0791c1fece8e	231	lookups will be faster (we exploit locality in TCP segment
RodColeman	0:0791c1fece8e	232	arrivals). */
RodColeman	0:0791c1fece8e	233	if (prev != NULL) {
RodColeman	0:0791c1fece8e	234	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
RodColeman	0:0791c1fece8e	235	/* our successor is the remainder of the listening list */
RodColeman	0:0791c1fece8e	236	lpcb->next = tcp_listen_pcbs.listen_pcbs;
RodColeman	0:0791c1fece8e	237	/* put this listening pcb at the head of the listening list */
RodColeman	0:0791c1fece8e	238	tcp_listen_pcbs.listen_pcbs = lpcb;
RodColeman	0:0791c1fece8e	239	}
RodColeman	0:0791c1fece8e	240
RodColeman	0:0791c1fece8e	241	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
RodColeman	0:0791c1fece8e	242	tcp_listen_input(lpcb);
RodColeman	0:0791c1fece8e	243	pbuf_free(p);
RodColeman	0:0791c1fece8e	244	return;
RodColeman	0:0791c1fece8e	245	}
RodColeman	0:0791c1fece8e	246	prev = (struct tcp_pcb *)lpcb;
RodColeman	0:0791c1fece8e	247	}
RodColeman	0:0791c1fece8e	248	}
RodColeman	0:0791c1fece8e	249
RodColeman	0:0791c1fece8e	250	#if TCP_INPUT_DEBUG
RodColeman	0:0791c1fece8e	251	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
RodColeman	0:0791c1fece8e	252	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
RodColeman	0:0791c1fece8e	253	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
RodColeman	0:0791c1fece8e	254	#endif /* TCP_INPUT_DEBUG */
RodColeman	0:0791c1fece8e	255
RodColeman	0:0791c1fece8e	256
RodColeman	0:0791c1fece8e	257	if (pcb != NULL) {
RodColeman	0:0791c1fece8e	258	/* The incoming segment belongs to a connection. */
RodColeman	0:0791c1fece8e	259	#if TCP_INPUT_DEBUG
RodColeman	0:0791c1fece8e	260	#if TCP_DEBUG
RodColeman	0:0791c1fece8e	261	tcp_debug_print_state(pcb->state);
RodColeman	0:0791c1fece8e	262	#endif /* TCP_DEBUG */
RodColeman	0:0791c1fece8e	263	#endif /* TCP_INPUT_DEBUG */
RodColeman	0:0791c1fece8e	264
RodColeman	0:0791c1fece8e	265	/* Set up a tcp_seg structure. */
RodColeman	0:0791c1fece8e	266	inseg.next = NULL;
RodColeman	0:0791c1fece8e	267	inseg.len = p->tot_len;
RodColeman	0:0791c1fece8e	268	inseg.dataptr = p->payload;
RodColeman	0:0791c1fece8e	269	inseg.p = p;
RodColeman	0:0791c1fece8e	270	inseg.tcphdr = tcphdr;
RodColeman	0:0791c1fece8e	271
RodColeman	0:0791c1fece8e	272	recv_data = NULL;
RodColeman	0:0791c1fece8e	273	recv_flags = 0;
RodColeman	0:0791c1fece8e	274
RodColeman	0:0791c1fece8e	275	/* If there is data which was previously "refused" by upper layer */
RodColeman	0:0791c1fece8e	276	if (pcb->refused_data != NULL) {
RodColeman	0:0791c1fece8e	277	/* Notify again application with data previously received. */
RodColeman	0:0791c1fece8e	278	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
RodColeman	0:0791c1fece8e	279	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
RodColeman	0:0791c1fece8e	280	if (err == ERR_OK) {
RodColeman	0:0791c1fece8e	281	pcb->refused_data = NULL;
RodColeman	0:0791c1fece8e	282	} else {
RodColeman	0:0791c1fece8e	283	/* drop incoming packets, because pcb is "full" */
RodColeman	0:0791c1fece8e	284	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
RodColeman	0:0791c1fece8e	285	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	286	snmp_inc_tcpinerrs();
RodColeman	0:0791c1fece8e	287	pbuf_free(p);
RodColeman	0:0791c1fece8e	288	return;
RodColeman	0:0791c1fece8e	289	}
RodColeman	0:0791c1fece8e	290	}
RodColeman	0:0791c1fece8e	291	tcp_input_pcb = pcb;
RodColeman	0:0791c1fece8e	292	err = tcp_process(pcb);
RodColeman	0:0791c1fece8e	293	tcp_input_pcb = NULL;
RodColeman	0:0791c1fece8e	294	/* A return value of ERR_ABRT means that tcp_abort() was called
RodColeman	0:0791c1fece8e	295	and that the pcb has been freed. If so, we don't do anything. */
RodColeman	0:0791c1fece8e	296	if (err != ERR_ABRT) {
RodColeman	0:0791c1fece8e	297	if (recv_flags & TF_RESET) {
RodColeman	0:0791c1fece8e	298	/* TF_RESET means that the connection was reset by the other
RodColeman	0:0791c1fece8e	299	end. We then call the error callback to inform the
RodColeman	0:0791c1fece8e	300	application that the connection is dead before we
RodColeman	0:0791c1fece8e	301	deallocate the PCB. */
RodColeman	0:0791c1fece8e	302	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
RodColeman	0:0791c1fece8e	303	tcp_pcb_remove(&tcp_active_pcbs, pcb);
RodColeman	0:0791c1fece8e	304	memp_free(MEMP_TCP_PCB, pcb);
RodColeman	0:0791c1fece8e	305	} else if (recv_flags & TF_CLOSED) {
RodColeman	0:0791c1fece8e	306	/* The connection has been closed and we will deallocate the
RodColeman	0:0791c1fece8e	307	PCB. */
RodColeman	0:0791c1fece8e	308	tcp_pcb_remove(&tcp_active_pcbs, pcb);
RodColeman	0:0791c1fece8e	309	memp_free(MEMP_TCP_PCB, pcb);
RodColeman	0:0791c1fece8e	310	} else {
RodColeman	0:0791c1fece8e	311	err = ERR_OK;
RodColeman	0:0791c1fece8e	312	/* If the application has registered a "sent" function to be
RodColeman	0:0791c1fece8e	313	called when new send buffer space is available, we call it
RodColeman	0:0791c1fece8e	314	now. */
RodColeman	0:0791c1fece8e	315	if (pcb->acked > 0) {
RodColeman	0:0791c1fece8e	316	TCP_EVENT_SENT(pcb, pcb->acked, err);
RodColeman	0:0791c1fece8e	317	}
RodColeman	0:0791c1fece8e	318
RodColeman	0:0791c1fece8e	319	if (recv_data != NULL) {
RodColeman	0:0791c1fece8e	320	if(flags & TCP_PSH) {
RodColeman	0:0791c1fece8e	321	recv_data->flags \|= PBUF_FLAG_PUSH;
RodColeman	0:0791c1fece8e	322	}
RodColeman	0:0791c1fece8e	323
RodColeman	0:0791c1fece8e	324	/* Notify application that data has been received. */
RodColeman	0:0791c1fece8e	325	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
RodColeman	0:0791c1fece8e	326
RodColeman	0:0791c1fece8e	327	/* If the upper layer can't receive this data, store it */
RodColeman	0:0791c1fece8e	328	if (err != ERR_OK) {
RodColeman	0:0791c1fece8e	329	pcb->refused_data = recv_data;
RodColeman	0:0791c1fece8e	330	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
RodColeman	0:0791c1fece8e	331	}
RodColeman	0:0791c1fece8e	332	}
RodColeman	0:0791c1fece8e	333
RodColeman	0:0791c1fece8e	334	/* If a FIN segment was received, we call the callback
RodColeman	0:0791c1fece8e	335	function with a NULL buffer to indicate EOF. */
RodColeman	0:0791c1fece8e	336	if (recv_flags & TF_GOT_FIN) {
RodColeman	0:0791c1fece8e	337	TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
RodColeman	0:0791c1fece8e	338	}
RodColeman	0:0791c1fece8e	339
RodColeman	0:0791c1fece8e	340	/* If there were no errors, we try to send something out. */
RodColeman	0:0791c1fece8e	341	if (err == ERR_OK) {
RodColeman	0:0791c1fece8e	342	tcp_output(pcb);
RodColeman	0:0791c1fece8e	343	}
RodColeman	0:0791c1fece8e	344	}
RodColeman	0:0791c1fece8e	345	}
RodColeman	0:0791c1fece8e	346
RodColeman	0:0791c1fece8e	347
RodColeman	0:0791c1fece8e	348	/* give up our reference to inseg.p */
RodColeman	0:0791c1fece8e	349	if (inseg.p != NULL)
RodColeman	0:0791c1fece8e	350	{
RodColeman	0:0791c1fece8e	351	pbuf_free(inseg.p);
RodColeman	0:0791c1fece8e	352	inseg.p = NULL;
RodColeman	0:0791c1fece8e	353	}
RodColeman	0:0791c1fece8e	354	#if TCP_INPUT_DEBUG
RodColeman	0:0791c1fece8e	355	#if TCP_DEBUG
RodColeman	0:0791c1fece8e	356	tcp_debug_print_state(pcb->state);
RodColeman	0:0791c1fece8e	357	#endif /* TCP_DEBUG */
RodColeman	0:0791c1fece8e	358	#endif /* TCP_INPUT_DEBUG */
RodColeman	0:0791c1fece8e	359
RodColeman	0:0791c1fece8e	360	} else {
RodColeman	0:0791c1fece8e	361
RodColeman	0:0791c1fece8e	362	/* If no matching PCB was found, send a TCP RST (reset) to the
RodColeman	0:0791c1fece8e	363	sender. */
RodColeman	0:0791c1fece8e	364	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
RodColeman	0:0791c1fece8e	365	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
RodColeman	0:0791c1fece8e	366	TCP_STATS_INC(tcp.proterr);
RodColeman	0:0791c1fece8e	367	TCP_STATS_INC(tcp.drop);
RodColeman	0:0791c1fece8e	368	tcp_rst(ackno, seqno + tcplen,
RodColeman	0:0791c1fece8e	369	&(iphdr->dest), &(iphdr->src),
RodColeman	0:0791c1fece8e	370	tcphdr->dest, tcphdr->src);
RodColeman	0:0791c1fece8e	371	}
RodColeman	0:0791c1fece8e	372	pbuf_free(p);
RodColeman	0:0791c1fece8e	373	}
RodColeman	0:0791c1fece8e	374
RodColeman	0:0791c1fece8e	375	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
RodColeman	0:0791c1fece8e	376	PERF_STOP("tcp_input");
RodColeman	0:0791c1fece8e	377	}
RodColeman	0:0791c1fece8e	378
RodColeman	0:0791c1fece8e	379	/**
RodColeman	0:0791c1fece8e	380	* Called by tcp_input() when a segment arrives for a listening
RodColeman	0:0791c1fece8e	381	* connection (from tcp_input()).
RodColeman	0:0791c1fece8e	382	*
RodColeman	0:0791c1fece8e	383	* @param pcb the tcp_pcb_listen for which a segment arrived
RodColeman	0:0791c1fece8e	384	* @return ERR_OK if the segment was processed
RodColeman	0:0791c1fece8e	385	* another err_t on error
RodColeman	0:0791c1fece8e	386	*
RodColeman	0:0791c1fece8e	387	* @note the return value is not (yet?) used in tcp_input()
RodColeman	0:0791c1fece8e	388	* @note the segment which arrived is saved in global variables, therefore only the pcb
RodColeman	0:0791c1fece8e	389	* involved is passed as a parameter to this function
RodColeman	0:0791c1fece8e	390	*/
RodColeman	0:0791c1fece8e	391	static err_t
RodColeman	0:0791c1fece8e	392	tcp_listen_input(struct tcp_pcb_listen *pcb)
RodColeman	0:0791c1fece8e	393	{
RodColeman	0:0791c1fece8e	394	struct tcp_pcb *npcb;
RodColeman	0:0791c1fece8e	395	err_t rc;
RodColeman	0:0791c1fece8e	396
RodColeman	0:0791c1fece8e	397	/* In the LISTEN state, we check for incoming SYN segments,
RodColeman	0:0791c1fece8e	398	creates a new PCB, and responds with a SYN\|ACK. */
RodColeman	0:0791c1fece8e	399	if (flags & TCP_ACK) {
RodColeman	0:0791c1fece8e	400	/* For incoming segments with the ACK flag set, respond with a
RodColeman	0:0791c1fece8e	401	RST. */
RodColeman	0:0791c1fece8e	402	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
RodColeman	0:0791c1fece8e	403	tcp_rst(ackno + 1, seqno + tcplen,
RodColeman	0:0791c1fece8e	404	&(iphdr->dest), &(iphdr->src),
RodColeman	0:0791c1fece8e	405	tcphdr->dest, tcphdr->src);
RodColeman	0:0791c1fece8e	406	} else if (flags & TCP_SYN) {
RodColeman	0:0791c1fece8e	407	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
RodColeman	0:0791c1fece8e	408	#if TCP_LISTEN_BACKLOG
RodColeman	0:0791c1fece8e	409	if (pcb->accepts_pending >= pcb->backlog) {
RodColeman	0:0791c1fece8e	410	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
RodColeman	0:0791c1fece8e	411	return ERR_ABRT;
RodColeman	0:0791c1fece8e	412	}
RodColeman	0:0791c1fece8e	413	#endif /* TCP_LISTEN_BACKLOG */
RodColeman	0:0791c1fece8e	414	npcb = tcp_alloc(pcb->prio);
RodColeman	0:0791c1fece8e	415	/* If a new PCB could not be created (probably due to lack of memory),
RodColeman	0:0791c1fece8e	416	we don't do anything, but rely on the sender will retransmit the
RodColeman	0:0791c1fece8e	417	SYN at a time when we have more memory available. */
RodColeman	0:0791c1fece8e	418	if (npcb == NULL) {
RodColeman	0:0791c1fece8e	419	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
RodColeman	0:0791c1fece8e	420	TCP_STATS_INC(tcp.memerr);
RodColeman	0:0791c1fece8e	421	return ERR_MEM;
RodColeman	0:0791c1fece8e	422	}
RodColeman	0:0791c1fece8e	423	#if TCP_LISTEN_BACKLOG
RodColeman	0:0791c1fece8e	424	pcb->accepts_pending++;
RodColeman	0:0791c1fece8e	425	#endif /* TCP_LISTEN_BACKLOG */
RodColeman	0:0791c1fece8e	426	/* Set up the new PCB. */
RodColeman	0:0791c1fece8e	427	ip_addr_set(&(npcb->local_ip), &(iphdr->dest));
RodColeman	0:0791c1fece8e	428	npcb->local_port = pcb->local_port;
RodColeman	0:0791c1fece8e	429	ip_addr_set(&(npcb->remote_ip), &(iphdr->src));
RodColeman	0:0791c1fece8e	430	npcb->remote_port = tcphdr->src;
RodColeman	0:0791c1fece8e	431	npcb->state = SYN_RCVD;
RodColeman	0:0791c1fece8e	432	npcb->rcv_nxt = seqno + 1;
RodColeman	0:0791c1fece8e	433	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
RodColeman	0:0791c1fece8e	434	npcb->snd_wnd = tcphdr->wnd;
RodColeman	0:0791c1fece8e	435	npcb->ssthresh = npcb->snd_wnd;
RodColeman	0:0791c1fece8e	436	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
RodColeman	0:0791c1fece8e	437	npcb->callback_arg = pcb->callback_arg;
RodColeman	0:0791c1fece8e	438	#if LWIP_CALLBACK_API
RodColeman	0:0791c1fece8e	439	npcb->accept = pcb->accept;
RodColeman	0:0791c1fece8e	440	#endif /* LWIP_CALLBACK_API */
RodColeman	0:0791c1fece8e	441	/* inherit socket options */
RodColeman	0:0791c1fece8e	442	npcb->so_options = pcb->so_options & (SOF_DEBUG\|SOF_DONTROUTE\|SOF_KEEPALIVE\|SOF_OOBINLINE\|SOF_LINGER);
RodColeman	0:0791c1fece8e	443	/* Register the new PCB so that we can begin receiving segments
RodColeman	0:0791c1fece8e	444	for it. */
RodColeman	0:0791c1fece8e	445	TCP_REG(&tcp_active_pcbs, npcb);
RodColeman	0:0791c1fece8e	446
RodColeman	0:0791c1fece8e	447	/* Parse any options in the SYN. */
RodColeman	0:0791c1fece8e	448	tcp_parseopt(npcb);
RodColeman	0:0791c1fece8e	449	#if TCP_CALCULATE_EFF_SEND_MSS
RodColeman	0:0791c1fece8e	450	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
RodColeman	0:0791c1fece8e	451	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
RodColeman	0:0791c1fece8e	452
RodColeman	0:0791c1fece8e	453	snmp_inc_tcppassiveopens();
RodColeman	0:0791c1fece8e	454
RodColeman	0:0791c1fece8e	455	/* Send a SYN\|ACK together with the MSS option. */
RodColeman	0:0791c1fece8e	456	rc = tcp_enqueue(npcb, NULL, 0, TCP_SYN \| TCP_ACK, 0, TF_SEG_OPTS_MSS
RodColeman	0:0791c1fece8e	457	#if LWIP_TCP_TIMESTAMPS
RodColeman	0:0791c1fece8e	458	/* and maybe include the TIMESTAMP option */
RodColeman	0:0791c1fece8e	459	\| (npcb->flags & TF_TIMESTAMP ? TF_SEG_OPTS_TS : 0)
RodColeman	0:0791c1fece8e	460	#endif
RodColeman	0:0791c1fece8e	461	);
RodColeman	0:0791c1fece8e	462	if (rc != ERR_OK) {
RodColeman	0:0791c1fece8e	463	tcp_abandon(npcb, 0);
RodColeman	0:0791c1fece8e	464	return rc;
RodColeman	0:0791c1fece8e	465	}
RodColeman	0:0791c1fece8e	466	return tcp_output(npcb);
RodColeman	0:0791c1fece8e	467	}
RodColeman	0:0791c1fece8e	468	return ERR_OK;
RodColeman	0:0791c1fece8e	469	}
RodColeman	0:0791c1fece8e	470
RodColeman	0:0791c1fece8e	471	/**
RodColeman	0:0791c1fece8e	472	* Called by tcp_input() when a segment arrives for a connection in
RodColeman	0:0791c1fece8e	473	* TIME_WAIT.
RodColeman	0:0791c1fece8e	474	*
RodColeman	0:0791c1fece8e	475	* @param pcb the tcp_pcb for which a segment arrived
RodColeman	0:0791c1fece8e	476	*
RodColeman	0:0791c1fece8e	477	* @note the segment which arrived is saved in global variables, therefore only the pcb
RodColeman	0:0791c1fece8e	478	* involved is passed as a parameter to this function
RodColeman	0:0791c1fece8e	479	*/
RodColeman	0:0791c1fece8e	480	static err_t
RodColeman	0:0791c1fece8e	481	tcp_timewait_input(struct tcp_pcb *pcb)
RodColeman	0:0791c1fece8e	482	{
RodColeman	0:0791c1fece8e	483	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
RodColeman	0:0791c1fece8e	484	/* RFC 793 3.9 Event Processing - Segment Arrives:
RodColeman	0:0791c1fece8e	485	* - first check sequence number - we skip that one in TIME_WAIT (always
RodColeman	0:0791c1fece8e	486	* acceptable since we only send ACKs)
RodColeman	0:0791c1fece8e	487	* - second check the RST bit (... return) */
RodColeman	0:0791c1fece8e	488	if (flags & TCP_RST) {
RodColeman	0:0791c1fece8e	489	return ERR_OK;
RodColeman	0:0791c1fece8e	490	}
RodColeman	0:0791c1fece8e	491	/* - fourth, check the SYN bit, */
RodColeman	0:0791c1fece8e	492	if (flags & TCP_SYN) {
RodColeman	0:0791c1fece8e	493	/* If an incoming segment is not acceptable, an acknowledgment
RodColeman	0:0791c1fece8e	494	should be sent in reply */
RodColeman	0:0791c1fece8e	495	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
RodColeman	0:0791c1fece8e	496	/* If the SYN is in the window it is an error, send a reset */
RodColeman	0:0791c1fece8e	497	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
RodColeman	0:0791c1fece8e	498	tcphdr->dest, tcphdr->src);
RodColeman	0:0791c1fece8e	499	return ERR_OK;
RodColeman	0:0791c1fece8e	500	}
RodColeman	0:0791c1fece8e	501	} else if (flags & TCP_FIN) {
RodColeman	0:0791c1fece8e	502	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
RodColeman	0:0791c1fece8e	503	Restart the 2 MSL time-wait timeout.*/
RodColeman	0:0791c1fece8e	504	pcb->tmr = tcp_ticks;
RodColeman	0:0791c1fece8e	505	}
RodColeman	0:0791c1fece8e	506
RodColeman	0:0791c1fece8e	507	if ((tcplen > 0)) {
RodColeman	0:0791c1fece8e	508	/* Acknowledge data, FIN or out-of-window SYN */
RodColeman	0:0791c1fece8e	509	pcb->flags \|= TF_ACK_NOW;
RodColeman	0:0791c1fece8e	510	return tcp_output(pcb);
RodColeman	0:0791c1fece8e	511	}
RodColeman	0:0791c1fece8e	512	return ERR_OK;
RodColeman	0:0791c1fece8e	513	}
RodColeman	0:0791c1fece8e	514
RodColeman	0:0791c1fece8e	515	/**
RodColeman	0:0791c1fece8e	516	* Implements the TCP state machine. Called by tcp_input. In some
RodColeman	0:0791c1fece8e	517	* states tcp_receive() is called to receive data. The tcp_seg
RodColeman	0:0791c1fece8e	518	* argument will be freed by the caller (tcp_input()) unless the
RodColeman	0:0791c1fece8e	519	* recv_data pointer in the pcb is set.
RodColeman	0:0791c1fece8e	520	*
RodColeman	0:0791c1fece8e	521	* @param pcb the tcp_pcb for which a segment arrived
RodColeman	0:0791c1fece8e	522	*
RodColeman	0:0791c1fece8e	523	* @note the segment which arrived is saved in global variables, therefore only the pcb
RodColeman	0:0791c1fece8e	524	* involved is passed as a parameter to this function
RodColeman	0:0791c1fece8e	525	*/
RodColeman	0:0791c1fece8e	526	static err_t
RodColeman	0:0791c1fece8e	527	tcp_process(struct tcp_pcb *pcb)
RodColeman	0:0791c1fece8e	528	{
RodColeman	0:0791c1fece8e	529	struct tcp_seg *rseg;
RodColeman	0:0791c1fece8e	530	u8_t acceptable = 0;
RodColeman	0:0791c1fece8e	531	err_t err;
RodColeman	0:0791c1fece8e	532
RodColeman	0:0791c1fece8e	533	err = ERR_OK;
RodColeman	0:0791c1fece8e	534
RodColeman	0:0791c1fece8e	535	/* Process incoming RST segments. */
RodColeman	0:0791c1fece8e	536	if (flags & TCP_RST) {
RodColeman	0:0791c1fece8e	537	/* First, determine if the reset is acceptable. */
RodColeman	0:0791c1fece8e	538	if (pcb->state == SYN_SENT) {
RodColeman	0:0791c1fece8e	539	if (ackno == pcb->snd_nxt) {
RodColeman	0:0791c1fece8e	540	acceptable = 1;
RodColeman	0:0791c1fece8e	541	}
RodColeman	0:0791c1fece8e	542	} else {
RodColeman	0:0791c1fece8e	543	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
RodColeman	0:0791c1fece8e	544	pcb->rcv_nxt+pcb->rcv_wnd)) {
RodColeman	0:0791c1fece8e	545	acceptable = 1;
RodColeman	0:0791c1fece8e	546	}
RodColeman	0:0791c1fece8e	547	}
RodColeman	0:0791c1fece8e	548
RodColeman	0:0791c1fece8e	549	if (acceptable) {
RodColeman	0:0791c1fece8e	550	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
RodColeman	0:0791c1fece8e	551	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
RodColeman	0:0791c1fece8e	552	recv_flags \|= TF_RESET;
RodColeman	0:0791c1fece8e	553	pcb->flags &= ~TF_ACK_DELAY;
RodColeman	0:0791c1fece8e	554	return ERR_RST;
RodColeman	0:0791c1fece8e	555	} else {
RodColeman	0:0791c1fece8e	556	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
RodColeman	0:0791c1fece8e	557	seqno, pcb->rcv_nxt));
RodColeman	0:0791c1fece8e	558	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
RodColeman	0:0791c1fece8e	559	seqno, pcb->rcv_nxt));
RodColeman	0:0791c1fece8e	560	return ERR_OK;
RodColeman	0:0791c1fece8e	561	}
RodColeman	0:0791c1fece8e	562	}
RodColeman	0:0791c1fece8e	563
RodColeman	0:0791c1fece8e	564	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
RodColeman	0:0791c1fece8e	565	/* Cope with new connection attempt after remote end crashed */
RodColeman	0:0791c1fece8e	566	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	567	return ERR_OK;
RodColeman	0:0791c1fece8e	568	}
RodColeman	0:0791c1fece8e	569
RodColeman	0:0791c1fece8e	570	/* Update the PCB (in)activity timer. */
RodColeman	0:0791c1fece8e	571	pcb->tmr = tcp_ticks;
RodColeman	0:0791c1fece8e	572	pcb->keep_cnt_sent = 0;
RodColeman	0:0791c1fece8e	573
RodColeman	0:0791c1fece8e	574	tcp_parseopt(pcb);
RodColeman	0:0791c1fece8e	575
RodColeman	0:0791c1fece8e	576	/* Do different things depending on the TCP state. */
RodColeman	0:0791c1fece8e	577	switch (pcb->state) {
RodColeman	0:0791c1fece8e	578	case SYN_SENT:
RodColeman	0:0791c1fece8e	579	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
RodColeman	0:0791c1fece8e	580	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
RodColeman	0:0791c1fece8e	581	/* received SYN ACK with expected sequence number? */
RodColeman	0:0791c1fece8e	582	if ((flags & TCP_ACK) && (flags & TCP_SYN)
RodColeman	0:0791c1fece8e	583	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
RodColeman	0:0791c1fece8e	584	pcb->snd_buf++;
RodColeman	0:0791c1fece8e	585	pcb->rcv_nxt = seqno + 1;
RodColeman	0:0791c1fece8e	586	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
RodColeman	0:0791c1fece8e	587	pcb->lastack = ackno;
RodColeman	0:0791c1fece8e	588	pcb->snd_wnd = tcphdr->wnd;
RodColeman	0:0791c1fece8e	589	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
RodColeman	0:0791c1fece8e	590	pcb->state = ESTABLISHED;
RodColeman	0:0791c1fece8e	591
RodColeman	0:0791c1fece8e	592	#if TCP_CALCULATE_EFF_SEND_MSS
RodColeman	0:0791c1fece8e	593	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
RodColeman	0:0791c1fece8e	594	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
RodColeman	0:0791c1fece8e	595
RodColeman	0:0791c1fece8e	596	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
RodColeman	0:0791c1fece8e	597	* but for the default value of pcb->mss) */
RodColeman	0:0791c1fece8e	598	pcb->ssthresh = pcb->mss * 10;
RodColeman	0:0791c1fece8e	599
RodColeman	0:0791c1fece8e	600	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
RodColeman	0:0791c1fece8e	601	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
RodColeman	0:0791c1fece8e	602	--pcb->snd_queuelen;
RodColeman	0:0791c1fece8e	603	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
RodColeman	0:0791c1fece8e	604	rseg = pcb->unacked;
RodColeman	0:0791c1fece8e	605	pcb->unacked = rseg->next;
RodColeman	0:0791c1fece8e	606
RodColeman	0:0791c1fece8e	607	/* If there's nothing left to acknowledge, stop the retransmit
RodColeman	0:0791c1fece8e	608	timer, otherwise reset it to start again */
RodColeman	0:0791c1fece8e	609	if(pcb->unacked == NULL)
RodColeman	0:0791c1fece8e	610	pcb->rtime = -1;
RodColeman	0:0791c1fece8e	611	else {
RodColeman	0:0791c1fece8e	612	pcb->rtime = 0;
RodColeman	0:0791c1fece8e	613	pcb->nrtx = 0;
RodColeman	0:0791c1fece8e	614	}
RodColeman	0:0791c1fece8e	615
RodColeman	0:0791c1fece8e	616	tcp_seg_free(rseg);
RodColeman	0:0791c1fece8e	617
RodColeman	0:0791c1fece8e	618	/* Call the user specified function to call when sucessfully
RodColeman	0:0791c1fece8e	619	* connected. */
RodColeman	0:0791c1fece8e	620	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
RodColeman	0:0791c1fece8e	621	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	622	}
RodColeman	0:0791c1fece8e	623	/* received ACK? possibly a half-open connection */
RodColeman	0:0791c1fece8e	624	else if (flags & TCP_ACK) {
RodColeman	0:0791c1fece8e	625	/* send a RST to bring the other side in a non-synchronized state. */
RodColeman	0:0791c1fece8e	626	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
RodColeman	0:0791c1fece8e	627	tcphdr->dest, tcphdr->src);
RodColeman	0:0791c1fece8e	628	}
RodColeman	0:0791c1fece8e	629	break;
RodColeman	0:0791c1fece8e	630	case SYN_RCVD:
RodColeman	0:0791c1fece8e	631	if (flags & TCP_ACK) {
RodColeman	0:0791c1fece8e	632	/* expected ACK number? */
RodColeman	0:0791c1fece8e	633	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
RodColeman	0:0791c1fece8e	634	u16_t old_cwnd;
RodColeman	0:0791c1fece8e	635	pcb->state = ESTABLISHED;
RodColeman	0:0791c1fece8e	636	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
RodColeman	0:0791c1fece8e	637	#if LWIP_CALLBACK_API
RodColeman	0:0791c1fece8e	638	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
RodColeman	0:0791c1fece8e	639	#endif
RodColeman	0:0791c1fece8e	640	/* Call the accept function. */
RodColeman	0:0791c1fece8e	641	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
RodColeman	0:0791c1fece8e	642	if (err != ERR_OK) {
RodColeman	0:0791c1fece8e	643	/* If the accept function returns with an error, we abort
RodColeman	0:0791c1fece8e	644	* the connection. */
RodColeman	0:0791c1fece8e	645	tcp_abort(pcb);
RodColeman	0:0791c1fece8e	646	return ERR_ABRT;
RodColeman	0:0791c1fece8e	647	}
RodColeman	0:0791c1fece8e	648	old_cwnd = pcb->cwnd;
RodColeman	0:0791c1fece8e	649	/* If there was any data contained within this ACK,
RodColeman	0:0791c1fece8e	650	* we'd better pass it on to the application as well. */
RodColeman	0:0791c1fece8e	651	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	652
RodColeman	0:0791c1fece8e	653	/* Prevent ACK for SYN to generate a sent event */
RodColeman	0:0791c1fece8e	654	if (pcb->acked != 0) {
RodColeman	0:0791c1fece8e	655	pcb->acked--;
RodColeman	0:0791c1fece8e	656	}
RodColeman	0:0791c1fece8e	657
RodColeman	0:0791c1fece8e	658	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
RodColeman	0:0791c1fece8e	659
RodColeman	0:0791c1fece8e	660	if (recv_flags & TF_GOT_FIN) {
RodColeman	0:0791c1fece8e	661	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	662	pcb->state = CLOSE_WAIT;
RodColeman	0:0791c1fece8e	663	}
RodColeman	0:0791c1fece8e	664	}
RodColeman	0:0791c1fece8e	665	/* incorrect ACK number */
RodColeman	0:0791c1fece8e	666	else {
RodColeman	0:0791c1fece8e	667	/* send RST */
RodColeman	0:0791c1fece8e	668	tcp_rst(ackno, seqno + tcplen, &(iphdr->dest), &(iphdr->src),
RodColeman	0:0791c1fece8e	669	tcphdr->dest, tcphdr->src);
RodColeman	0:0791c1fece8e	670	}
RodColeman	0:0791c1fece8e	671	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
RodColeman	0:0791c1fece8e	672	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
RodColeman	0:0791c1fece8e	673	tcp_rexmit(pcb);
RodColeman	0:0791c1fece8e	674	}
RodColeman	0:0791c1fece8e	675	break;
RodColeman	0:0791c1fece8e	676	case CLOSE_WAIT:
RodColeman	0:0791c1fece8e	677	/* FALLTHROUGH */
RodColeman	0:0791c1fece8e	678	case ESTABLISHED:
RodColeman	0:0791c1fece8e	679	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	680	if (recv_flags & TF_GOT_FIN) { /* passive close */
RodColeman	0:0791c1fece8e	681	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	682	pcb->state = CLOSE_WAIT;
RodColeman	0:0791c1fece8e	683	}
RodColeman	0:0791c1fece8e	684	break;
RodColeman	0:0791c1fece8e	685	case FIN_WAIT_1:
RodColeman	0:0791c1fece8e	686	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	687	if (recv_flags & TF_GOT_FIN) {
RodColeman	0:0791c1fece8e	688	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
RodColeman	0:0791c1fece8e	689	LWIP_DEBUGF(TCP_DEBUG,
RodColeman	0:0791c1fece8e	690	("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
RodColeman	0:0791c1fece8e	691	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	692	tcp_pcb_purge(pcb);
RodColeman	0:0791c1fece8e	693	TCP_RMV(&tcp_active_pcbs, pcb);
RodColeman	0:0791c1fece8e	694	pcb->state = TIME_WAIT;
RodColeman	0:0791c1fece8e	695	TCP_REG(&tcp_tw_pcbs, pcb);
RodColeman	0:0791c1fece8e	696	} else {
RodColeman	0:0791c1fece8e	697	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	698	pcb->state = CLOSING;
RodColeman	0:0791c1fece8e	699	}
RodColeman	0:0791c1fece8e	700	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
RodColeman	0:0791c1fece8e	701	pcb->state = FIN_WAIT_2;
RodColeman	0:0791c1fece8e	702	}
RodColeman	0:0791c1fece8e	703	break;
RodColeman	0:0791c1fece8e	704	case FIN_WAIT_2:
RodColeman	0:0791c1fece8e	705	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	706	if (recv_flags & TF_GOT_FIN) {
RodColeman	0:0791c1fece8e	707	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
RodColeman	0:0791c1fece8e	708	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	709	tcp_pcb_purge(pcb);
RodColeman	0:0791c1fece8e	710	TCP_RMV(&tcp_active_pcbs, pcb);
RodColeman	0:0791c1fece8e	711	pcb->state = TIME_WAIT;
RodColeman	0:0791c1fece8e	712	TCP_REG(&tcp_tw_pcbs, pcb);
RodColeman	0:0791c1fece8e	713	}
RodColeman	0:0791c1fece8e	714	break;
RodColeman	0:0791c1fece8e	715	case CLOSING:
RodColeman	0:0791c1fece8e	716	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	717	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
RodColeman	0:0791c1fece8e	718	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
RodColeman	0:0791c1fece8e	719	tcp_pcb_purge(pcb);
RodColeman	0:0791c1fece8e	720	TCP_RMV(&tcp_active_pcbs, pcb);
RodColeman	0:0791c1fece8e	721	pcb->state = TIME_WAIT;
RodColeman	0:0791c1fece8e	722	TCP_REG(&tcp_tw_pcbs, pcb);
RodColeman	0:0791c1fece8e	723	}
RodColeman	0:0791c1fece8e	724	break;
RodColeman	0:0791c1fece8e	725	case LAST_ACK:
RodColeman	0:0791c1fece8e	726	tcp_receive(pcb);
RodColeman	0:0791c1fece8e	727	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
RodColeman	0:0791c1fece8e	728	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
RodColeman	0:0791c1fece8e	729	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
RodColeman	0:0791c1fece8e	730	recv_flags \|= TF_CLOSED;
RodColeman	0:0791c1fece8e	731	}
RodColeman	0:0791c1fece8e	732	break;
RodColeman	0:0791c1fece8e	733	default:
RodColeman	0:0791c1fece8e	734	break;
RodColeman	0:0791c1fece8e	735	}
RodColeman	0:0791c1fece8e	736	return ERR_OK;
RodColeman	0:0791c1fece8e	737	}
RodColeman	0:0791c1fece8e	738
RodColeman	0:0791c1fece8e	739	/**
RodColeman	0:0791c1fece8e	740	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
RodColeman	0:0791c1fece8e	741	* data, and if so frees the memory of the buffered data. Next, is places the
RodColeman	0:0791c1fece8e	742	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
RodColeman	0:0791c1fece8e	743	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
RodColeman	0:0791c1fece8e	744	* i it has been removed from the buffer.
RodColeman	0:0791c1fece8e	745	*
RodColeman	0:0791c1fece8e	746	* If the incoming segment constitutes an ACK for a segment that was used for RTT
RodColeman	0:0791c1fece8e	747	* estimation, the RTT is estimated here as well.
RodColeman	0:0791c1fece8e	748	*
RodColeman	0:0791c1fece8e	749	* Called from tcp_process().
RodColeman	0:0791c1fece8e	750	*
RodColeman	0:0791c1fece8e	751	* @return 1 if the incoming segment is the next in sequence, 0 if not
RodColeman	0:0791c1fece8e	752	*/
RodColeman	0:0791c1fece8e	753	static u8_t
RodColeman	0:0791c1fece8e	754	tcp_receive(struct tcp_pcb *pcb)
RodColeman	0:0791c1fece8e	755	{
RodColeman	0:0791c1fece8e	756	struct tcp_seg *next;
RodColeman	0:0791c1fece8e	757	#if TCP_QUEUE_OOSEQ
RodColeman	0:0791c1fece8e	758	struct tcp_seg prev, cseg;
RodColeman	0:0791c1fece8e	759	#endif
RodColeman	0:0791c1fece8e	760	struct pbuf *p;
RodColeman	0:0791c1fece8e	761	s32_t off;
RodColeman	0:0791c1fece8e	762	s16_t m;
RodColeman	0:0791c1fece8e	763	u32_t right_wnd_edge;
RodColeman	0:0791c1fece8e	764	u16_t new_tot_len;
RodColeman	0:0791c1fece8e	765	u8_t accepted_inseq = 0;
RodColeman	0:0791c1fece8e	766	int found_dupack = 0;
RodColeman	0:0791c1fece8e	767
RodColeman	0:0791c1fece8e	768	if (flags & TCP_ACK) {
RodColeman	0:0791c1fece8e	769	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
RodColeman	0:0791c1fece8e	770
RodColeman	0:0791c1fece8e	771	/* Update window. */
RodColeman	0:0791c1fece8e	772	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
RodColeman	0:0791c1fece8e	773	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
RodColeman	0:0791c1fece8e	774	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
RodColeman	0:0791c1fece8e	775	pcb->snd_wnd = tcphdr->wnd;
RodColeman	0:0791c1fece8e	776	pcb->snd_wl1 = seqno;
RodColeman	0:0791c1fece8e	777	pcb->snd_wl2 = ackno;
RodColeman	0:0791c1fece8e	778	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
RodColeman	0:0791c1fece8e	779	pcb->persist_backoff = 0;
RodColeman	0:0791c1fece8e	780	}
RodColeman	0:0791c1fece8e	781	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
RodColeman	0:0791c1fece8e	782	#if TCP_WND_DEBUG
RodColeman	0:0791c1fece8e	783	} else {
RodColeman	0:0791c1fece8e	784	if (pcb->snd_wnd != tcphdr->wnd) {
RodColeman	0:0791c1fece8e	785	LWIP_DEBUGF(TCP_WND_DEBUG,
RodColeman	0:0791c1fece8e	786	("tcp_receive: no window update lastack %"U32_F" ackno %"
RodColeman	0:0791c1fece8e	787	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
RodColeman	0:0791c1fece8e	788	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
RodColeman	0:0791c1fece8e	789	}
RodColeman	0:0791c1fece8e	790	#endif /* TCP_WND_DEBUG */
RodColeman	0:0791c1fece8e	791	}
RodColeman	0:0791c1fece8e	792
RodColeman	0:0791c1fece8e	793	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
RodColeman	0:0791c1fece8e	794	* duplicate ack if:
RodColeman	0:0791c1fece8e	795	* 1) It doesn't ACK new data
RodColeman	0:0791c1fece8e	796	* 2) length of received packet is zero (i.e. no payload)
RodColeman	0:0791c1fece8e	797	* 3) the advertised window hasn't changed
RodColeman	0:0791c1fece8e	798	* 4) There is outstanding unacknowledged data (retransmission timer running)
RodColeman	0:0791c1fece8e	799	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
RodColeman	0:0791c1fece8e	800	*
RodColeman	0:0791c1fece8e	801	* If it passes all five, should process as a dupack:
RodColeman	0:0791c1fece8e	802	* a) dupacks < 3: do nothing
RodColeman	0:0791c1fece8e	803	* b) dupacks == 3: fast retransmit
RodColeman	0:0791c1fece8e	804	* c) dupacks > 3: increase cwnd
RodColeman	0:0791c1fece8e	805	*
RodColeman	0:0791c1fece8e	806	* If it only passes 1-3, should reset dupack counter (and add to
RodColeman	0:0791c1fece8e	807	* stats, which we don't do in lwIP)
RodColeman	0:0791c1fece8e	808	*
RodColeman	0:0791c1fece8e	809	* If it only passes 1, should reset dupack counter
RodColeman	0:0791c1fece8e	810	*
RodColeman	0:0791c1fece8e	811	*/
RodColeman	0:0791c1fece8e	812
RodColeman	0:0791c1fece8e	813	/* Clause 1 */
RodColeman	0:0791c1fece8e	814	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
RodColeman	0:0791c1fece8e	815	pcb->acked = 0;
RodColeman	0:0791c1fece8e	816	/* Clause 2 */
RodColeman	0:0791c1fece8e	817	if (tcplen == 0) {
RodColeman	0:0791c1fece8e	818	/* Clause 3 */
RodColeman	0:0791c1fece8e	819	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
RodColeman	0:0791c1fece8e	820	/* Clause 4 */
RodColeman	0:0791c1fece8e	821	if (pcb->rtime >= 0) {
RodColeman	0:0791c1fece8e	822	/* Clause 5 */
RodColeman	0:0791c1fece8e	823	if (pcb->lastack == ackno) {
RodColeman	0:0791c1fece8e	824	found_dupack = 1;
RodColeman	0:0791c1fece8e	825	if (pcb->dupacks + 1 > pcb->dupacks)
RodColeman	0:0791c1fece8e	826	++pcb->dupacks;
RodColeman	0:0791c1fece8e	827	if (pcb->dupacks > 3) {
RodColeman	0:0791c1fece8e	828	/* Inflate the congestion window, but not if it means that
RodColeman	0:0791c1fece8e	829	the value overflows. */
RodColeman	0:0791c1fece8e	830	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
RodColeman	0:0791c1fece8e	831	pcb->cwnd += pcb->mss;
RodColeman	0:0791c1fece8e	832	}
RodColeman	0:0791c1fece8e	833	} else if (pcb->dupacks == 3) {
RodColeman	0:0791c1fece8e	834	/* Do fast retransmit */
RodColeman	0:0791c1fece8e	835	tcp_rexmit_fast(pcb);
RodColeman	0:0791c1fece8e	836	}
RodColeman	0:0791c1fece8e	837	}
RodColeman	0:0791c1fece8e	838	}
RodColeman	0:0791c1fece8e	839	}
RodColeman	0:0791c1fece8e	840	}
RodColeman	0:0791c1fece8e	841	/* If Clause (1) or more is true, but not a duplicate ack, reset
RodColeman	0:0791c1fece8e	842	* count of consecutive duplicate acks */
RodColeman	0:0791c1fece8e	843	if (!found_dupack) {
RodColeman	0:0791c1fece8e	844	pcb->dupacks = 0;
RodColeman	0:0791c1fece8e	845	}
RodColeman	0:0791c1fece8e	846	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
RodColeman	0:0791c1fece8e	847	/* We come here when the ACK acknowledges new data. */
RodColeman	0:0791c1fece8e	848
RodColeman	0:0791c1fece8e	849	/* Reset the "IN Fast Retransmit" flag, since we are no longer
RodColeman	0:0791c1fece8e	850	in fast retransmit. Also reset the congestion window to the
RodColeman	0:0791c1fece8e	851	slow start threshold. */
RodColeman	0:0791c1fece8e	852	if (pcb->flags & TF_INFR) {
RodColeman	0:0791c1fece8e	853	pcb->flags &= ~TF_INFR;
RodColeman	0:0791c1fece8e	854	pcb->cwnd = pcb->ssthresh;
RodColeman	0:0791c1fece8e	855	}
RodColeman	0:0791c1fece8e	856
RodColeman	0:0791c1fece8e	857	/* Reset the number of retransmissions. */
RodColeman	0:0791c1fece8e	858	pcb->nrtx = 0;
RodColeman	0:0791c1fece8e	859
RodColeman	0:0791c1fece8e	860	/* Reset the retransmission time-out. */
RodColeman	0:0791c1fece8e	861	pcb->rto = (pcb->sa >> 3) + pcb->sv;
RodColeman	0:0791c1fece8e	862
RodColeman	0:0791c1fece8e	863	/* Update the send buffer space. Diff between the two can never exceed 64K? */
RodColeman	0:0791c1fece8e	864	pcb->acked = (u16_t)(ackno - pcb->lastack);
RodColeman	0:0791c1fece8e	865
RodColeman	0:0791c1fece8e	866	pcb->snd_buf += pcb->acked;
RodColeman	0:0791c1fece8e	867
RodColeman	0:0791c1fece8e	868	/* Reset the fast retransmit variables. */
RodColeman	0:0791c1fece8e	869	pcb->dupacks = 0;
RodColeman	0:0791c1fece8e	870	pcb->lastack = ackno;
RodColeman	0:0791c1fece8e	871
RodColeman	0:0791c1fece8e	872	/* Update the congestion control variables (cwnd and
RodColeman	0:0791c1fece8e	873	ssthresh). */
RodColeman	0:0791c1fece8e	874	if (pcb->state >= ESTABLISHED) {
RodColeman	0:0791c1fece8e	875	if (pcb->cwnd < pcb->ssthresh) {
RodColeman	0:0791c1fece8e	876	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
RodColeman	0:0791c1fece8e	877	pcb->cwnd += pcb->mss;
RodColeman	0:0791c1fece8e	878	}
RodColeman	0:0791c1fece8e	879	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
RodColeman	0:0791c1fece8e	880	} else {
RodColeman	0:0791c1fece8e	881	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
RodColeman	0:0791c1fece8e	882	if (new_cwnd > pcb->cwnd) {
RodColeman	0:0791c1fece8e	883	pcb->cwnd = new_cwnd;
RodColeman	0:0791c1fece8e	884	}
RodColeman	0:0791c1fece8e	885	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
RodColeman	0:0791c1fece8e	886	}
RodColeman	0:0791c1fece8e	887	}
RodColeman	0:0791c1fece8e	888	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
RodColeman	0:0791c1fece8e	889	ackno,
RodColeman	0:0791c1fece8e	890	pcb->unacked != NULL?
RodColeman	0:0791c1fece8e	891	ntohl(pcb->unacked->tcphdr->seqno): 0,
RodColeman	0:0791c1fece8e	892	pcb->unacked != NULL?
RodColeman	0:0791c1fece8e	893	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
RodColeman	0:0791c1fece8e	894
RodColeman	0:0791c1fece8e	895	/* Remove segment from the unacknowledged list if the incoming
RodColeman	0:0791c1fece8e	896	ACK acknowlegdes them. */
RodColeman	0:0791c1fece8e	897	while (pcb->unacked != NULL &&
RodColeman	0:0791c1fece8e	898	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
RodColeman	0:0791c1fece8e	899	TCP_TCPLEN(pcb->unacked), ackno)) {
RodColeman	0:0791c1fece8e	900	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
RodColeman	0:0791c1fece8e	901	ntohl(pcb->unacked->tcphdr->seqno),
RodColeman	0:0791c1fece8e	902	ntohl(pcb->unacked->tcphdr->seqno) +
RodColeman	0:0791c1fece8e	903	TCP_TCPLEN(pcb->unacked)));
RodColeman	0:0791c1fece8e	904
RodColeman	0:0791c1fece8e	905	next = pcb->unacked;
RodColeman	0:0791c1fece8e	906	pcb->unacked = pcb->unacked->next;
RodColeman	0:0791c1fece8e	907
RodColeman	0:0791c1fece8e	908	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
RodColeman	0:0791c1fece8e	909	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
RodColeman	0:0791c1fece8e	910	/* Prevent ACK for FIN to generate a sent event */
RodColeman	0:0791c1fece8e	911	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
RodColeman	0:0791c1fece8e	912	pcb->acked--;
RodColeman	0:0791c1fece8e	913	}
RodColeman	0:0791c1fece8e	914
RodColeman	0:0791c1fece8e	915	pcb->snd_queuelen -= pbuf_clen(next->p);
RodColeman	0:0791c1fece8e	916	tcp_seg_free(next);
RodColeman	0:0791c1fece8e	917
RodColeman	0:0791c1fece8e	918	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
RodColeman	0:0791c1fece8e	919	if (pcb->snd_queuelen != 0) {
RodColeman	0:0791c1fece8e	920	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
RodColeman	0:0791c1fece8e	921	pcb->unsent != NULL);
RodColeman	0:0791c1fece8e	922	}
RodColeman	0:0791c1fece8e	923	}
RodColeman	0:0791c1fece8e	924
RodColeman	0:0791c1fece8e	925	/* If there's nothing left to acknowledge, stop the retransmit
RodColeman	0:0791c1fece8e	926	timer, otherwise reset it to start again */
RodColeman	0:0791c1fece8e	927	if(pcb->unacked == NULL)
RodColeman	0:0791c1fece8e	928	pcb->rtime = -1;
RodColeman	0:0791c1fece8e	929	else
RodColeman	0:0791c1fece8e	930	pcb->rtime = 0;
RodColeman	0:0791c1fece8e	931
RodColeman	0:0791c1fece8e	932	pcb->polltmr = 0;
RodColeman	0:0791c1fece8e	933	} else {
RodColeman	0:0791c1fece8e	934	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
RodColeman	0:0791c1fece8e	935	pcb->acked = 0;
RodColeman	0:0791c1fece8e	936	}
RodColeman	0:0791c1fece8e	937
RodColeman	0:0791c1fece8e	938	/* We go through the ->unsent list to see if any of the segments
RodColeman	0:0791c1fece8e	939	on the list are acknowledged by the ACK. This may seem
RodColeman	0:0791c1fece8e	940	strange since an "unsent" segment shouldn't be acked. The
RodColeman	0:0791c1fece8e	941	rationale is that lwIP puts all outstanding segments on the
RodColeman	0:0791c1fece8e	942	->unsent list after a retransmission, so these segments may
RodColeman	0:0791c1fece8e	943	in fact have been sent once. */
RodColeman	0:0791c1fece8e	944	while (pcb->unsent != NULL &&
RodColeman	0:0791c1fece8e	945	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
RodColeman	0:0791c1fece8e	946	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
RodColeman	0:0791c1fece8e	947	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
RodColeman	0:0791c1fece8e	948	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
RodColeman	0:0791c1fece8e	949	TCP_TCPLEN(pcb->unsent)));
RodColeman	0:0791c1fece8e	950
RodColeman	0:0791c1fece8e	951	next = pcb->unsent;
RodColeman	0:0791c1fece8e	952	pcb->unsent = pcb->unsent->next;
RodColeman	0:0791c1fece8e	953	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
RodColeman	0:0791c1fece8e	954	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
RodColeman	0:0791c1fece8e	955	/* Prevent ACK for FIN to generate a sent event */
RodColeman	0:0791c1fece8e	956	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
RodColeman	0:0791c1fece8e	957	pcb->acked--;
RodColeman	0:0791c1fece8e	958	}
RodColeman	0:0791c1fece8e	959	pcb->snd_queuelen -= pbuf_clen(next->p);
RodColeman	0:0791c1fece8e	960	tcp_seg_free(next);
RodColeman	0:0791c1fece8e	961	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
RodColeman	0:0791c1fece8e	962	if (pcb->snd_queuelen != 0) {
RodColeman	0:0791c1fece8e	963	LWIP_ASSERT("tcp_receive: valid queue length",
RodColeman	0:0791c1fece8e	964	pcb->unacked != NULL \|\| pcb->unsent != NULL);
RodColeman	0:0791c1fece8e	965	}
RodColeman	0:0791c1fece8e	966	}
RodColeman	0:0791c1fece8e	967	/* End of ACK for new data processing. */
RodColeman	0:0791c1fece8e	968
RodColeman	0:0791c1fece8e	969	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
RodColeman	0:0791c1fece8e	970	pcb->rttest, pcb->rtseq, ackno));
RodColeman	0:0791c1fece8e	971
RodColeman	0:0791c1fece8e	972	/* RTT estimation calculations. This is done by checking if the
RodColeman	0:0791c1fece8e	973	incoming segment acknowledges the segment we use to take a
RodColeman	0:0791c1fece8e	974	round-trip time measurement. */
RodColeman	0:0791c1fece8e	975	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
RodColeman	0:0791c1fece8e	976	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
RodColeman	0:0791c1fece8e	977	and a round-trip shouldn't be that long... */
RodColeman	0:0791c1fece8e	978	m = (s16_t)(tcp_ticks - pcb->rttest);
RodColeman	0:0791c1fece8e	979
RodColeman	0:0791c1fece8e	980	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
RodColeman	0:0791c1fece8e	981	m, m * TCP_SLOW_INTERVAL));
RodColeman	0:0791c1fece8e	982
RodColeman	0:0791c1fece8e	983	/* This is taken directly from VJs original code in his paper */
RodColeman	0:0791c1fece8e	984	m = m - (pcb->sa >> 3);
RodColeman	0:0791c1fece8e	985	pcb->sa += m;
RodColeman	0:0791c1fece8e	986	if (m < 0) {
RodColeman	0:0791c1fece8e	987	m = -m;
RodColeman	0:0791c1fece8e	988	}
RodColeman	0:0791c1fece8e	989	m = m - (pcb->sv >> 2);
RodColeman	0:0791c1fece8e	990	pcb->sv += m;
RodColeman	0:0791c1fece8e	991	pcb->rto = (pcb->sa >> 3) + pcb->sv;
RodColeman	0:0791c1fece8e	992
RodColeman	0:0791c1fece8e	993	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
RodColeman	0:0791c1fece8e	994	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
RodColeman	0:0791c1fece8e	995
RodColeman	0:0791c1fece8e	996	pcb->rttest = 0;
RodColeman	0:0791c1fece8e	997	}
RodColeman	0:0791c1fece8e	998	}
RodColeman	0:0791c1fece8e	999
RodColeman	0:0791c1fece8e	1000	/* If the incoming segment contains data, we must process it
RodColeman	0:0791c1fece8e	1001	further. */
RodColeman	0:0791c1fece8e	1002	if (tcplen > 0) {
RodColeman	0:0791c1fece8e	1003	/* This code basically does three things:
RodColeman	0:0791c1fece8e	1004
RodColeman	0:0791c1fece8e	1005	+) If the incoming segment contains data that is the next
RodColeman	0:0791c1fece8e	1006	in-sequence data, this data is passed to the application. This
RodColeman	0:0791c1fece8e	1007	might involve trimming the first edge of the data. The rcv_nxt
RodColeman	0:0791c1fece8e	1008	variable and the advertised window are adjusted.
RodColeman	0:0791c1fece8e	1009
RodColeman	0:0791c1fece8e	1010	+) If the incoming segment has data that is above the next
RodColeman	0:0791c1fece8e	1011	sequence number expected (->rcv_nxt), the segment is placed on
RodColeman	0:0791c1fece8e	1012	the ->ooseq queue. This is done by finding the appropriate
RodColeman	0:0791c1fece8e	1013	place in the ->ooseq queue (which is ordered by sequence
RodColeman	0:0791c1fece8e	1014	number) and trim the segment in both ends if needed. An
RodColeman	0:0791c1fece8e	1015	immediate ACK is sent to indicate that we received an
RodColeman	0:0791c1fece8e	1016	out-of-sequence segment.
RodColeman	0:0791c1fece8e	1017
RodColeman	0:0791c1fece8e	1018	+) Finally, we check if the first segment on the ->ooseq queue
RodColeman	0:0791c1fece8e	1019	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
RodColeman	0:0791c1fece8e	1020	rcv_nxt > ooseq->seqno, we must trim the first edge of the
RodColeman	0:0791c1fece8e	1021	segment on ->ooseq before we adjust rcv_nxt. The data in the
RodColeman	0:0791c1fece8e	1022	segments that are now on sequence are chained onto the
RodColeman	0:0791c1fece8e	1023	incoming segment so that we only need to call the application
RodColeman	0:0791c1fece8e	1024	once.
RodColeman	0:0791c1fece8e	1025	*/
RodColeman	0:0791c1fece8e	1026
RodColeman	0:0791c1fece8e	1027	/* First, we check if we must trim the first edge. We have to do
RodColeman	0:0791c1fece8e	1028	this if the sequence number of the incoming segment is less
RodColeman	0:0791c1fece8e	1029	than rcv_nxt, and the sequence number plus the length of the
RodColeman	0:0791c1fece8e	1030	segment is larger than rcv_nxt. */
RodColeman	0:0791c1fece8e	1031	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
RodColeman	0:0791c1fece8e	1032	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
RodColeman	0:0791c1fece8e	1033	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
RodColeman	0:0791c1fece8e	1034	/* Trimming the first edge is done by pushing the payload
RodColeman	0:0791c1fece8e	1035	pointer in the pbuf downwards. This is somewhat tricky since
RodColeman	0:0791c1fece8e	1036	we do not want to discard the full contents of the pbuf up to
RodColeman	0:0791c1fece8e	1037	the new starting point of the data since we have to keep the
RodColeman	0:0791c1fece8e	1038	TCP header which is present in the first pbuf in the chain.
RodColeman	0:0791c1fece8e	1039
RodColeman	0:0791c1fece8e	1040	What is done is really quite a nasty hack: the first pbuf in
RodColeman	0:0791c1fece8e	1041	the pbuf chain is pointed to by inseg.p. Since we need to be
RodColeman	0:0791c1fece8e	1042	able to deallocate the whole pbuf, we cannot change this
RodColeman	0:0791c1fece8e	1043	inseg.p pointer to point to any of the later pbufs in the
RodColeman	0:0791c1fece8e	1044	chain. Instead, we point the ->payload pointer in the first
RodColeman	0:0791c1fece8e	1045	pbuf to data in one of the later pbufs. We also set the
RodColeman	0:0791c1fece8e	1046	inseg.data pointer to point to the right place. This way, the
RodColeman	0:0791c1fece8e	1047	->p pointer will still point to the first pbuf, but the
RodColeman	0:0791c1fece8e	1048	->p->payload pointer will point to data in another pbuf.
RodColeman	0:0791c1fece8e	1049
RodColeman	0:0791c1fece8e	1050	After we are done with adjusting the pbuf pointers we must
RodColeman	0:0791c1fece8e	1051	adjust the ->data pointer in the seg and the segment
RodColeman	0:0791c1fece8e	1052	length.*/
RodColeman	0:0791c1fece8e	1053
RodColeman	0:0791c1fece8e	1054	off = pcb->rcv_nxt - seqno;
RodColeman	0:0791c1fece8e	1055	p = inseg.p;
RodColeman	0:0791c1fece8e	1056	LWIP_ASSERT("inseg.p != NULL", inseg.p);
RodColeman	0:0791c1fece8e	1057	LWIP_ASSERT("insane offset!", (off < 0x7fff));
RodColeman	0:0791c1fece8e	1058	if (inseg.p->len < off) {
RodColeman	0:0791c1fece8e	1059	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
RodColeman	0:0791c1fece8e	1060	new_tot_len = (u16_t)(inseg.p->tot_len - off);
RodColeman	0:0791c1fece8e	1061	while (p->len < off) {
RodColeman	0:0791c1fece8e	1062	off -= p->len;
RodColeman	0:0791c1fece8e	1063	/* KJM following line changed (with addition of new_tot_len var)
RodColeman	0:0791c1fece8e	1064	to fix bug #9076
RodColeman	0:0791c1fece8e	1065	inseg.p->tot_len -= p->len; */
RodColeman	0:0791c1fece8e	1066	p->tot_len = new_tot_len;
RodColeman	0:0791c1fece8e	1067	p->len = 0;
RodColeman	0:0791c1fece8e	1068	p = p->next;
RodColeman	0:0791c1fece8e	1069	}
RodColeman	0:0791c1fece8e	1070	if(pbuf_header(p, (s16_t)-off)) {
RodColeman	0:0791c1fece8e	1071	/* Do we need to cope with this failing? Assert for now */
RodColeman	0:0791c1fece8e	1072	LWIP_ASSERT("pbuf_header failed", 0);
RodColeman	0:0791c1fece8e	1073	}
RodColeman	0:0791c1fece8e	1074	} else {
RodColeman	0:0791c1fece8e	1075	if(pbuf_header(inseg.p, (s16_t)-off)) {
RodColeman	0:0791c1fece8e	1076	/* Do we need to cope with this failing? Assert for now */
RodColeman	0:0791c1fece8e	1077	LWIP_ASSERT("pbuf_header failed", 0);
RodColeman	0:0791c1fece8e	1078	}
RodColeman	0:0791c1fece8e	1079	}
RodColeman	0:0791c1fece8e	1080	/* KJM following line changed to use p->payload rather than inseg->p->payload
RodColeman	0:0791c1fece8e	1081	to fix bug #9076 */
RodColeman	0:0791c1fece8e	1082	inseg.dataptr = p->payload;
RodColeman	0:0791c1fece8e	1083	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
RodColeman	0:0791c1fece8e	1084	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
RodColeman	0:0791c1fece8e	1085	}
RodColeman	0:0791c1fece8e	1086	else {
RodColeman	0:0791c1fece8e	1087	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
RodColeman	0:0791c1fece8e	1088	/* the whole segment is < rcv_nxt */
RodColeman	0:0791c1fece8e	1089	/* must be a duplicate of a packet that has already been correctly handled */
RodColeman	0:0791c1fece8e	1090
RodColeman	0:0791c1fece8e	1091	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
RodColeman	0:0791c1fece8e	1092	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	1093	}
RodColeman	0:0791c1fece8e	1094	}
RodColeman	0:0791c1fece8e	1095
RodColeman	0:0791c1fece8e	1096	/* The sequence number must be within the window (above rcv_nxt
RodColeman	0:0791c1fece8e	1097	and below rcv_nxt + rcv_wnd) in order to be further
RodColeman	0:0791c1fece8e	1098	processed. */
RodColeman	0:0791c1fece8e	1099	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
RodColeman	0:0791c1fece8e	1100	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
RodColeman	0:0791c1fece8e	1101	if (pcb->rcv_nxt == seqno) {
RodColeman	0:0791c1fece8e	1102	accepted_inseq = 1;
RodColeman	0:0791c1fece8e	1103	/* The incoming segment is the next in sequence. We check if
RodColeman	0:0791c1fece8e	1104	we have to trim the end of the segment and update rcv_nxt
RodColeman	0:0791c1fece8e	1105	and pass the data to the application. */
RodColeman	0:0791c1fece8e	1106	tcplen = TCP_TCPLEN(&inseg);
RodColeman	0:0791c1fece8e	1107
RodColeman	0:0791c1fece8e	1108	if (tcplen > pcb->rcv_wnd) {
RodColeman	0:0791c1fece8e	1109	LWIP_DEBUGF(TCP_INPUT_DEBUG,
RodColeman	0:0791c1fece8e	1110	("tcp_receive: other end overran receive window"
RodColeman	0:0791c1fece8e	1111	"seqno %"U32_F" len %"U32_F" right edge %"U32_F"\n",
RodColeman	0:0791c1fece8e	1112	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
RodColeman	0:0791c1fece8e	1113	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
RodColeman	0:0791c1fece8e	1114	/* Must remove the FIN from the header as we're trimming
RodColeman	0:0791c1fece8e	1115	* that byte of sequence-space from the packet */
RodColeman	0:0791c1fece8e	1116	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
RodColeman	0:0791c1fece8e	1117	}
RodColeman	0:0791c1fece8e	1118	/* Adjust length of segment to fit in the window. */
RodColeman	0:0791c1fece8e	1119	inseg.len = pcb->rcv_wnd;
RodColeman	0:0791c1fece8e	1120	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
RodColeman	0:0791c1fece8e	1121	inseg.len -= 1;
RodColeman	0:0791c1fece8e	1122	}
RodColeman	0:0791c1fece8e	1123	pbuf_realloc(inseg.p, inseg.len);
RodColeman	0:0791c1fece8e	1124	tcplen = TCP_TCPLEN(&inseg);
RodColeman	0:0791c1fece8e	1125	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
RodColeman	0:0791c1fece8e	1126	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
RodColeman	0:0791c1fece8e	1127	}
RodColeman	0:0791c1fece8e	1128	#if TCP_QUEUE_OOSEQ
RodColeman	0:0791c1fece8e	1129	if (pcb->ooseq != NULL) {
RodColeman	0:0791c1fece8e	1130	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
RodColeman	0:0791c1fece8e	1131	LWIP_DEBUGF(TCP_INPUT_DEBUG,
RodColeman	0:0791c1fece8e	1132	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
RodColeman	0:0791c1fece8e	1133	/* Received in-order FIN means anything that was received
RodColeman	0:0791c1fece8e	1134	* out of order must now have been received in-order, so
RodColeman	0:0791c1fece8e	1135	* bin the ooseq queue */
RodColeman	0:0791c1fece8e	1136	while (pcb->ooseq != NULL) {
RodColeman	0:0791c1fece8e	1137	struct tcp_seg *old_ooseq = pcb->ooseq;
RodColeman	0:0791c1fece8e	1138	pcb->ooseq = pcb->ooseq->next;
RodColeman	0:0791c1fece8e	1139	memp_free(MEMP_TCP_SEG, old_ooseq);
RodColeman	0:0791c1fece8e	1140	}
RodColeman	0:0791c1fece8e	1141	} else if (TCP_SEQ_LEQ(pcb->ooseq->tcphdr->seqno, seqno + tcplen)) {
RodColeman	0:0791c1fece8e	1142	if (pcb->ooseq->len > 0) {
RodColeman	0:0791c1fece8e	1143	/* We have to trim the second edge of the incoming segment. */
RodColeman	0:0791c1fece8e	1144	LWIP_ASSERT("tcp_receive: trimmed segment would have zero length\n",
RodColeman	0:0791c1fece8e	1145	TCP_SEQ_GT(pcb->ooseq->tcphdr->seqno, seqno));
RodColeman	0:0791c1fece8e	1146	/* FIN in inseg already handled by dropping whole ooseq queue */
RodColeman	0:0791c1fece8e	1147	inseg.len = (u16_t)(pcb->ooseq->tcphdr->seqno - seqno);
RodColeman	0:0791c1fece8e	1148	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
RodColeman	0:0791c1fece8e	1149	inseg.len -= 1;
RodColeman	0:0791c1fece8e	1150	}
RodColeman	0:0791c1fece8e	1151	pbuf_realloc(inseg.p, inseg.len);
RodColeman	0:0791c1fece8e	1152	tcplen = TCP_TCPLEN(&inseg);
RodColeman	0:0791c1fece8e	1153	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
RodColeman	0:0791c1fece8e	1154	(seqno + tcplen) == pcb->ooseq->tcphdr->seqno);
RodColeman	0:0791c1fece8e	1155	} else {
RodColeman	0:0791c1fece8e	1156	/* does the ooseq segment contain only flags that are in inseg also? */
RodColeman	0:0791c1fece8e	1157	if ((TCPH_FLAGS(inseg.tcphdr) & (TCP_FIN\|TCP_SYN)) ==
RodColeman	0:0791c1fece8e	1158	(TCPH_FLAGS(pcb->ooseq->tcphdr) & (TCP_FIN\|TCP_SYN))) {
RodColeman	0:0791c1fece8e	1159	struct tcp_seg *old_ooseq = pcb->ooseq;
RodColeman	0:0791c1fece8e	1160	pcb->ooseq = pcb->ooseq->next;
RodColeman	0:0791c1fece8e	1161	memp_free(MEMP_TCP_SEG, old_ooseq);
RodColeman	0:0791c1fece8e	1162	}
RodColeman	0:0791c1fece8e	1163	}
RodColeman	0:0791c1fece8e	1164	}
RodColeman	0:0791c1fece8e	1165	}
RodColeman	0:0791c1fece8e	1166	#endif /* TCP_QUEUE_OOSEQ */
RodColeman	0:0791c1fece8e	1167
RodColeman	0:0791c1fece8e	1168	pcb->rcv_nxt = seqno + tcplen;
RodColeman	0:0791c1fece8e	1169
RodColeman	0:0791c1fece8e	1170	/* Update the receiver's (our) window. */
RodColeman	0:0791c1fece8e	1171	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
RodColeman	0:0791c1fece8e	1172	pcb->rcv_wnd -= tcplen;
RodColeman	0:0791c1fece8e	1173
RodColeman	0:0791c1fece8e	1174	tcp_update_rcv_ann_wnd(pcb);
RodColeman	0:0791c1fece8e	1175
RodColeman	0:0791c1fece8e	1176	/* If there is data in the segment, we make preparations to
RodColeman	0:0791c1fece8e	1177	pass this up to the application. The ->recv_data variable
RodColeman	0:0791c1fece8e	1178	is used for holding the pbuf that goes to the
RodColeman	0:0791c1fece8e	1179	application. The code for reassembling out-of-sequence data
RodColeman	0:0791c1fece8e	1180	chains its data on this pbuf as well.
RodColeman	0:0791c1fece8e	1181
RodColeman	0:0791c1fece8e	1182	If the segment was a FIN, we set the TF_GOT_FIN flag that will
RodColeman	0:0791c1fece8e	1183	be used to indicate to the application that the remote side has
RodColeman	0:0791c1fece8e	1184	closed its end of the connection. */
RodColeman	0:0791c1fece8e	1185	if (inseg.p->tot_len > 0) {
RodColeman	0:0791c1fece8e	1186	recv_data = inseg.p;
RodColeman	0:0791c1fece8e	1187	/* Since this pbuf now is the responsibility of the
RodColeman	0:0791c1fece8e	1188	application, we delete our reference to it so that we won't
RodColeman	0:0791c1fece8e	1189	(mistakingly) deallocate it. */
RodColeman	0:0791c1fece8e	1190	inseg.p = NULL;
RodColeman	0:0791c1fece8e	1191	}
RodColeman	0:0791c1fece8e	1192	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
RodColeman	0:0791c1fece8e	1193	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
RodColeman	0:0791c1fece8e	1194	recv_flags \|= TF_GOT_FIN;
RodColeman	0:0791c1fece8e	1195	}
RodColeman	0:0791c1fece8e	1196
RodColeman	0:0791c1fece8e	1197	#if TCP_QUEUE_OOSEQ
RodColeman	0:0791c1fece8e	1198	/* We now check if we have segments on the ->ooseq queue that
RodColeman	0:0791c1fece8e	1199	is now in sequence. */
RodColeman	0:0791c1fece8e	1200	while (pcb->ooseq != NULL &&
RodColeman	0:0791c1fece8e	1201	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
RodColeman	0:0791c1fece8e	1202
RodColeman	0:0791c1fece8e	1203	cseg = pcb->ooseq;
RodColeman	0:0791c1fece8e	1204	seqno = pcb->ooseq->tcphdr->seqno;
RodColeman	0:0791c1fece8e	1205
RodColeman	0:0791c1fece8e	1206	pcb->rcv_nxt += TCP_TCPLEN(cseg);
RodColeman	0:0791c1fece8e	1207	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
RodColeman	0:0791c1fece8e	1208	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
RodColeman	0:0791c1fece8e	1209	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
RodColeman	0:0791c1fece8e	1210
RodColeman	0:0791c1fece8e	1211	tcp_update_rcv_ann_wnd(pcb);
RodColeman	0:0791c1fece8e	1212
RodColeman	0:0791c1fece8e	1213	if (cseg->p->tot_len > 0) {
RodColeman	0:0791c1fece8e	1214	/* Chain this pbuf onto the pbuf that we will pass to
RodColeman	0:0791c1fece8e	1215	the application. */
RodColeman	0:0791c1fece8e	1216	if (recv_data) {
RodColeman	0:0791c1fece8e	1217	pbuf_cat(recv_data, cseg->p);
RodColeman	0:0791c1fece8e	1218	} else {
RodColeman	0:0791c1fece8e	1219	recv_data = cseg->p;
RodColeman	0:0791c1fece8e	1220	}
RodColeman	0:0791c1fece8e	1221	cseg->p = NULL;
RodColeman	0:0791c1fece8e	1222	}
RodColeman	0:0791c1fece8e	1223	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
RodColeman	0:0791c1fece8e	1224	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
RodColeman	0:0791c1fece8e	1225	recv_flags \|= TF_GOT_FIN;
RodColeman	0:0791c1fece8e	1226	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
RodColeman	0:0791c1fece8e	1227	pcb->state = CLOSE_WAIT;
RodColeman	0:0791c1fece8e	1228	}
RodColeman	0:0791c1fece8e	1229	}
RodColeman	0:0791c1fece8e	1230
RodColeman	0:0791c1fece8e	1231
RodColeman	0:0791c1fece8e	1232	pcb->ooseq = cseg->next;
RodColeman	0:0791c1fece8e	1233	tcp_seg_free(cseg);
RodColeman	0:0791c1fece8e	1234	}
RodColeman	0:0791c1fece8e	1235	#endif /* TCP_QUEUE_OOSEQ */
RodColeman	0:0791c1fece8e	1236
RodColeman	0:0791c1fece8e	1237
RodColeman	0:0791c1fece8e	1238	/* Acknowledge the segment(s). */
RodColeman	0:0791c1fece8e	1239	tcp_ack(pcb);
RodColeman	0:0791c1fece8e	1240
RodColeman	0:0791c1fece8e	1241	} else {
RodColeman	0:0791c1fece8e	1242	/* We get here if the incoming segment is out-of-sequence. */
RodColeman	0:0791c1fece8e	1243	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	1244	#if TCP_QUEUE_OOSEQ
RodColeman	0:0791c1fece8e	1245	/* We queue the segment on the ->ooseq queue. */
RodColeman	0:0791c1fece8e	1246	if (pcb->ooseq == NULL) {
RodColeman	0:0791c1fece8e	1247	pcb->ooseq = tcp_seg_copy(&inseg);
RodColeman	0:0791c1fece8e	1248	} else {
RodColeman	0:0791c1fece8e	1249	/* If the queue is not empty, we walk through the queue and
RodColeman	0:0791c1fece8e	1250	try to find a place where the sequence number of the
RodColeman	0:0791c1fece8e	1251	incoming segment is between the sequence numbers of the
RodColeman	0:0791c1fece8e	1252	previous and the next segment on the ->ooseq queue. That is
RodColeman	0:0791c1fece8e	1253	the place where we put the incoming segment. If needed, we
RodColeman	0:0791c1fece8e	1254	trim the second edges of the previous and the incoming
RodColeman	0:0791c1fece8e	1255	segment so that it will fit into the sequence.
RodColeman	0:0791c1fece8e	1256
RodColeman	0:0791c1fece8e	1257	If the incoming segment has the same sequence number as a
RodColeman	0:0791c1fece8e	1258	segment on the ->ooseq queue, we discard the segment that
RodColeman	0:0791c1fece8e	1259	contains less data. */
RodColeman	0:0791c1fece8e	1260
RodColeman	0:0791c1fece8e	1261	prev = NULL;
RodColeman	0:0791c1fece8e	1262	for(next = pcb->ooseq; next != NULL; next = next->next) {
RodColeman	0:0791c1fece8e	1263	if (seqno == next->tcphdr->seqno) {
RodColeman	0:0791c1fece8e	1264	/* The sequence number of the incoming segment is the
RodColeman	0:0791c1fece8e	1265	same as the sequence number of the segment on
RodColeman	0:0791c1fece8e	1266	->ooseq. We check the lengths to see which one to
RodColeman	0:0791c1fece8e	1267	discard. */
RodColeman	0:0791c1fece8e	1268	if (inseg.len > next->len) {
RodColeman	0:0791c1fece8e	1269	/* The incoming segment is larger than the old
RodColeman	0:0791c1fece8e	1270	segment. We replace the old segment with the new
RodColeman	0:0791c1fece8e	1271	one. */
RodColeman	0:0791c1fece8e	1272	cseg = tcp_seg_copy(&inseg);
RodColeman	0:0791c1fece8e	1273	if (cseg != NULL) {
RodColeman	0:0791c1fece8e	1274	cseg->next = next->next;
RodColeman	0:0791c1fece8e	1275	if (prev != NULL) {
RodColeman	0:0791c1fece8e	1276	prev->next = cseg;
RodColeman	0:0791c1fece8e	1277	} else {
RodColeman	0:0791c1fece8e	1278	pcb->ooseq = cseg;
RodColeman	0:0791c1fece8e	1279	}
RodColeman	0:0791c1fece8e	1280	tcp_seg_free(next);
RodColeman	0:0791c1fece8e	1281	if (cseg->next != NULL) {
RodColeman	0:0791c1fece8e	1282	next = cseg->next;
RodColeman	0:0791c1fece8e	1283	if (TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
RodColeman	0:0791c1fece8e	1284	/* We need to trim the incoming segment. */
RodColeman	0:0791c1fece8e	1285	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
RodColeman	0:0791c1fece8e	1286	pbuf_realloc(cseg->p, cseg->len);
RodColeman	0:0791c1fece8e	1287	}
RodColeman	0:0791c1fece8e	1288	}
RodColeman	0:0791c1fece8e	1289	}
RodColeman	0:0791c1fece8e	1290	break;
RodColeman	0:0791c1fece8e	1291	} else {
RodColeman	0:0791c1fece8e	1292	/* Either the lenghts are the same or the incoming
RodColeman	0:0791c1fece8e	1293	segment was smaller than the old one; in either
RodColeman	0:0791c1fece8e	1294	case, we ditch the incoming segment. */
RodColeman	0:0791c1fece8e	1295	break;
RodColeman	0:0791c1fece8e	1296	}
RodColeman	0:0791c1fece8e	1297	} else {
RodColeman	0:0791c1fece8e	1298	if (prev == NULL) {
RodColeman	0:0791c1fece8e	1299	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
RodColeman	0:0791c1fece8e	1300	/* The sequence number of the incoming segment is lower
RodColeman	0:0791c1fece8e	1301	than the sequence number of the first segment on the
RodColeman	0:0791c1fece8e	1302	queue. We put the incoming segment first on the
RodColeman	0:0791c1fece8e	1303	queue. */
RodColeman	0:0791c1fece8e	1304
RodColeman	0:0791c1fece8e	1305	if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) {
RodColeman	0:0791c1fece8e	1306	/* We need to trim the incoming segment. */
RodColeman	0:0791c1fece8e	1307	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
RodColeman	0:0791c1fece8e	1308	pbuf_realloc(inseg.p, inseg.len);
RodColeman	0:0791c1fece8e	1309	}
RodColeman	0:0791c1fece8e	1310	cseg = tcp_seg_copy(&inseg);
RodColeman	0:0791c1fece8e	1311	if (cseg != NULL) {
RodColeman	0:0791c1fece8e	1312	cseg->next = next;
RodColeman	0:0791c1fece8e	1313	pcb->ooseq = cseg;
RodColeman	0:0791c1fece8e	1314	}
RodColeman	0:0791c1fece8e	1315	break;
RodColeman	0:0791c1fece8e	1316	}
RodColeman	0:0791c1fece8e	1317	} else
RodColeman	0:0791c1fece8e	1318	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
RodColeman	0:0791c1fece8e	1319	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
RodColeman	0:0791c1fece8e	1320	if(TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)){
RodColeman	0:0791c1fece8e	1321	/* The sequence number of the incoming segment is in
RodColeman	0:0791c1fece8e	1322	between the sequence numbers of the previous and
RodColeman	0:0791c1fece8e	1323	the next segment on ->ooseq. We trim and insert the
RodColeman	0:0791c1fece8e	1324	incoming segment and trim the previous segment, if
RodColeman	0:0791c1fece8e	1325	needed. */
RodColeman	0:0791c1fece8e	1326	if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) {
RodColeman	0:0791c1fece8e	1327	/* We need to trim the incoming segment. */
RodColeman	0:0791c1fece8e	1328	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
RodColeman	0:0791c1fece8e	1329	pbuf_realloc(inseg.p, inseg.len);
RodColeman	0:0791c1fece8e	1330	}
RodColeman	0:0791c1fece8e	1331
RodColeman	0:0791c1fece8e	1332	cseg = tcp_seg_copy(&inseg);
RodColeman	0:0791c1fece8e	1333	if (cseg != NULL) {
RodColeman	0:0791c1fece8e	1334	cseg->next = next;
RodColeman	0:0791c1fece8e	1335	prev->next = cseg;
RodColeman	0:0791c1fece8e	1336	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
RodColeman	0:0791c1fece8e	1337	/* We need to trim the prev segment. */
RodColeman	0:0791c1fece8e	1338	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
RodColeman	0:0791c1fece8e	1339	pbuf_realloc(prev->p, prev->len);
RodColeman	0:0791c1fece8e	1340	}
RodColeman	0:0791c1fece8e	1341	}
RodColeman	0:0791c1fece8e	1342	break;
RodColeman	0:0791c1fece8e	1343	}
RodColeman	0:0791c1fece8e	1344	/* If the "next" segment is the last segment on the
RodColeman	0:0791c1fece8e	1345	ooseq queue, we add the incoming segment to the end
RodColeman	0:0791c1fece8e	1346	of the list. */
RodColeman	0:0791c1fece8e	1347	if (next->next == NULL &&
RodColeman	0:0791c1fece8e	1348	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
RodColeman	0:0791c1fece8e	1349	next->next = tcp_seg_copy(&inseg);
RodColeman	0:0791c1fece8e	1350	if (next->next != NULL) {
RodColeman	0:0791c1fece8e	1351	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
RodColeman	0:0791c1fece8e	1352	/* We need to trim the last segment. */
RodColeman	0:0791c1fece8e	1353	next->len = (u16_t)(seqno - next->tcphdr->seqno);
RodColeman	0:0791c1fece8e	1354	pbuf_realloc(next->p, next->len);
RodColeman	0:0791c1fece8e	1355	}
RodColeman	0:0791c1fece8e	1356	}
RodColeman	0:0791c1fece8e	1357	break;
RodColeman	0:0791c1fece8e	1358	}
RodColeman	0:0791c1fece8e	1359	}
RodColeman	0:0791c1fece8e	1360	prev = next;
RodColeman	0:0791c1fece8e	1361	}
RodColeman	0:0791c1fece8e	1362	}
RodColeman	0:0791c1fece8e	1363	#endif /* TCP_QUEUE_OOSEQ */
RodColeman	0:0791c1fece8e	1364
RodColeman	0:0791c1fece8e	1365	}
RodColeman	0:0791c1fece8e	1366	} else {
RodColeman	0:0791c1fece8e	1367	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	1368	}
RodColeman	0:0791c1fece8e	1369	} else {
RodColeman	0:0791c1fece8e	1370	/* Segments with length 0 is taken care of here. Segments that
RodColeman	0:0791c1fece8e	1371	fall out of the window are ACKed. */
RodColeman	0:0791c1fece8e	1372	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
RodColeman	0:0791c1fece8e	1373	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
RodColeman	0:0791c1fece8e	1374	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
RodColeman	0:0791c1fece8e	1375	tcp_ack_now(pcb);
RodColeman	0:0791c1fece8e	1376	}
RodColeman	0:0791c1fece8e	1377	}
RodColeman	0:0791c1fece8e	1378	return accepted_inseq;
RodColeman	0:0791c1fece8e	1379	}
RodColeman	0:0791c1fece8e	1380
RodColeman	0:0791c1fece8e	1381	/**
RodColeman	0:0791c1fece8e	1382	* Parses the options contained in the incoming segment.
RodColeman	0:0791c1fece8e	1383	*
RodColeman	0:0791c1fece8e	1384	* Called from tcp_listen_input() and tcp_process().
RodColeman	0:0791c1fece8e	1385	* Currently, only the MSS option is supported!
RodColeman	0:0791c1fece8e	1386	*
RodColeman	0:0791c1fece8e	1387	* @param pcb the tcp_pcb for which a segment arrived
RodColeman	0:0791c1fece8e	1388	*/
RodColeman	0:0791c1fece8e	1389	static void
RodColeman	0:0791c1fece8e	1390	tcp_parseopt(struct tcp_pcb *pcb)
RodColeman	0:0791c1fece8e	1391	{
RodColeman	0:0791c1fece8e	1392	u16_t c, max_c;
RodColeman	0:0791c1fece8e	1393	u16_t mss;
RodColeman	0:0791c1fece8e	1394	u8_t *opts, opt;
RodColeman	0:0791c1fece8e	1395	#if LWIP_TCP_TIMESTAMPS
RodColeman	0:0791c1fece8e	1396	u32_t tsval;
RodColeman	0:0791c1fece8e	1397	#endif
RodColeman	0:0791c1fece8e	1398
RodColeman	0:0791c1fece8e	1399	opts = (u8_t *)tcphdr + TCP_HLEN;
RodColeman	0:0791c1fece8e	1400
RodColeman	0:0791c1fece8e	1401	/* Parse the TCP MSS option, if present. */
RodColeman	0:0791c1fece8e	1402	if(TCPH_HDRLEN(tcphdr) > 0x5) {
RodColeman	0:0791c1fece8e	1403	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
RodColeman	0:0791c1fece8e	1404	for (c = 0; c < max_c; ) {
RodColeman	0:0791c1fece8e	1405	opt = opts[c];
RodColeman	0:0791c1fece8e	1406	switch (opt) {
RodColeman	0:0791c1fece8e	1407	case 0x00:
RodColeman	0:0791c1fece8e	1408	/* End of options. */
RodColeman	0:0791c1fece8e	1409	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
RodColeman	0:0791c1fece8e	1410	return;
RodColeman	0:0791c1fece8e	1411	case 0x01:
RodColeman	0:0791c1fece8e	1412	/* NOP option. */
RodColeman	0:0791c1fece8e	1413	++c;
RodColeman	0:0791c1fece8e	1414	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
RodColeman	0:0791c1fece8e	1415	break;
RodColeman	0:0791c1fece8e	1416	case 0x02:
RodColeman	0:0791c1fece8e	1417	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
RodColeman	0:0791c1fece8e	1418	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
RodColeman	0:0791c1fece8e	1419	/* Bad length */
RodColeman	0:0791c1fece8e	1420	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
RodColeman	0:0791c1fece8e	1421	return;
RodColeman	0:0791c1fece8e	1422	}
RodColeman	0:0791c1fece8e	1423	/* An MSS option with the right option length. */
RodColeman	0:0791c1fece8e	1424	mss = (opts[c + 2] << 8) \| opts[c + 3];
RodColeman	0:0791c1fece8e	1425	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
RodColeman	0:0791c1fece8e	1426	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
RodColeman	0:0791c1fece8e	1427	/* Advance to next option */
RodColeman	0:0791c1fece8e	1428	c += 0x04;
RodColeman	0:0791c1fece8e	1429	break;
RodColeman	0:0791c1fece8e	1430	#if LWIP_TCP_TIMESTAMPS
RodColeman	0:0791c1fece8e	1431	case 0x08:
RodColeman	0:0791c1fece8e	1432	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
RodColeman	0:0791c1fece8e	1433	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
RodColeman	0:0791c1fece8e	1434	/* Bad length */
RodColeman	0:0791c1fece8e	1435	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
RodColeman	0:0791c1fece8e	1436	return;
RodColeman	0:0791c1fece8e	1437	}
RodColeman	0:0791c1fece8e	1438	/* TCP timestamp option with valid length */
RodColeman	0:0791c1fece8e	1439	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
RodColeman	0:0791c1fece8e	1440	(opts[c+4] << 16) \| (opts[c+5] << 24);
RodColeman	0:0791c1fece8e	1441	if (flags & TCP_SYN) {
RodColeman	0:0791c1fece8e	1442	pcb->ts_recent = ntohl(tsval);
RodColeman	0:0791c1fece8e	1443	pcb->flags \|= TF_TIMESTAMP;
RodColeman	0:0791c1fece8e	1444	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
RodColeman	0:0791c1fece8e	1445	pcb->ts_recent = ntohl(tsval);
RodColeman	0:0791c1fece8e	1446	}
RodColeman	0:0791c1fece8e	1447	/* Advance to next option */
RodColeman	0:0791c1fece8e	1448	c += 0x0A;
RodColeman	0:0791c1fece8e	1449	break;
RodColeman	0:0791c1fece8e	1450	#endif
RodColeman	0:0791c1fece8e	1451	default:
RodColeman	0:0791c1fece8e	1452	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
RodColeman	0:0791c1fece8e	1453	if (opts[c + 1] == 0) {
RodColeman	0:0791c1fece8e	1454	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
RodColeman	0:0791c1fece8e	1455	/* If the length field is zero, the options are malformed
RodColeman	0:0791c1fece8e	1456	and we don't process them further. */
RodColeman	0:0791c1fece8e	1457	return;
RodColeman	0:0791c1fece8e	1458	}
RodColeman	0:0791c1fece8e	1459	/* All other options have a length field, so that we easily
RodColeman	0:0791c1fece8e	1460	can skip past them. */
RodColeman	0:0791c1fece8e	1461	c += opts[c + 1];
RodColeman	0:0791c1fece8e	1462	}
RodColeman	0:0791c1fece8e	1463	}
RodColeman	0:0791c1fece8e	1464	}
RodColeman	0:0791c1fece8e	1465	}
RodColeman	0:0791c1fece8e	1466
RodColeman	0:0791c1fece8e	1467	#endif /* LWIP_TCP */

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Type:	Library
Created:	21 Aug 2013
Imports:	60
Forks:	0
Commits:	1
Dependents:	2
Dependencies:	0
Followers:	5

The code in this repository is Apache licensed.

Core/lwIP/core/tcp_in.c@0:0791c1fece8e, 2012-09-18 (annotated)

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