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lwip/core/tcp_in.c@0:ac1725ba162c, 2010-11-09 (annotated)

Committer:: segundo
Date:: Tue Nov 09 20:54:15 2010 +0000
Revision:: 0:ac1725ba162c

Who changed what in which revision?

User	Revision	Line number	New contents of line
segundo	0:ac1725ba162c	1	/**
segundo	0:ac1725ba162c	2	* @file
segundo	0:ac1725ba162c	3	* Transmission Control Protocol, incoming traffic
segundo	0:ac1725ba162c	4	*
segundo	0:ac1725ba162c	5	* The input processing functions of the TCP layer.
segundo	0:ac1725ba162c	6	*
segundo	0:ac1725ba162c	7	* These functions are generally called in the order (ip_input() ->)
segundo	0:ac1725ba162c	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
segundo	0:ac1725ba162c	9	*
segundo	0:ac1725ba162c	10	*/
segundo	0:ac1725ba162c	11
segundo	0:ac1725ba162c	12	/*
segundo	0:ac1725ba162c	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
segundo	0:ac1725ba162c	14	* All rights reserved.
segundo	0:ac1725ba162c	15	*
segundo	0:ac1725ba162c	16	* Redistribution and use in source and binary forms, with or without modification,
segundo	0:ac1725ba162c	17	* are permitted provided that the following conditions are met:
segundo	0:ac1725ba162c	18	*
segundo	0:ac1725ba162c	19	* 1. Redistributions of source code must retain the above copyright notice,
segundo	0:ac1725ba162c	20	* this list of conditions and the following disclaimer.
segundo	0:ac1725ba162c	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
segundo	0:ac1725ba162c	22	* this list of conditions and the following disclaimer in the documentation
segundo	0:ac1725ba162c	23	* and/or other materials provided with the distribution.
segundo	0:ac1725ba162c	24	* 3. The name of the author may not be used to endorse or promote products
segundo	0:ac1725ba162c	25	* derived from this software without specific prior written permission.
segundo	0:ac1725ba162c	26	*
segundo	0:ac1725ba162c	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
segundo	0:ac1725ba162c	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
segundo	0:ac1725ba162c	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
segundo	0:ac1725ba162c	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
segundo	0:ac1725ba162c	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
segundo	0:ac1725ba162c	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
segundo	0:ac1725ba162c	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
segundo	0:ac1725ba162c	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
segundo	0:ac1725ba162c	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
segundo	0:ac1725ba162c	36	* OF SUCH DAMAGE.
segundo	0:ac1725ba162c	37	*
segundo	0:ac1725ba162c	38	* This file is part of the lwIP TCP/IP stack.
segundo	0:ac1725ba162c	39	*
segundo	0:ac1725ba162c	40	* Author: Adam Dunkels <adam@sics.se>
segundo	0:ac1725ba162c	41	*
segundo	0:ac1725ba162c	42	*/
segundo	0:ac1725ba162c	43
segundo	0:ac1725ba162c	44	#include "lwip/opt.h"
segundo	0:ac1725ba162c	45
segundo	0:ac1725ba162c	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
segundo	0:ac1725ba162c	47
segundo	0:ac1725ba162c	48	#include "lwip/tcp_impl.h"
segundo	0:ac1725ba162c	49	#include "lwip/def.h"
segundo	0:ac1725ba162c	50	#include "lwip/ip_addr.h"
segundo	0:ac1725ba162c	51	#include "lwip/netif.h"
segundo	0:ac1725ba162c	52	#include "lwip/mem.h"
segundo	0:ac1725ba162c	53	#include "lwip/memp.h"
segundo	0:ac1725ba162c	54	#include "lwip/inet_chksum.h"
segundo	0:ac1725ba162c	55	#include "lwip/stats.h"
segundo	0:ac1725ba162c	56	#include "lwip/snmp.h"
segundo	0:ac1725ba162c	57	#include "arch/perf.h"
segundo	0:ac1725ba162c	58
segundo	0:ac1725ba162c	59	/* These variables are global to all functions involved in the input
segundo	0:ac1725ba162c	60	processing of TCP segments. They are set by the tcp_input()
segundo	0:ac1725ba162c	61	function. */
segundo	0:ac1725ba162c	62	static struct tcp_seg inseg;
segundo	0:ac1725ba162c	63	static struct tcp_hdr *tcphdr;
segundo	0:ac1725ba162c	64	static struct ip_hdr *iphdr;
segundo	0:ac1725ba162c	65	static u32_t seqno, ackno;
segundo	0:ac1725ba162c	66	static u8_t flags;
segundo	0:ac1725ba162c	67	static u16_t tcplen;
segundo	0:ac1725ba162c	68
segundo	0:ac1725ba162c	69	static u8_t recv_flags;
segundo	0:ac1725ba162c	70	static struct pbuf *recv_data;
segundo	0:ac1725ba162c	71
segundo	0:ac1725ba162c	72	struct tcp_pcb *tcp_input_pcb;
segundo	0:ac1725ba162c	73
segundo	0:ac1725ba162c	74	/* Forward declarations. */
segundo	0:ac1725ba162c	75	static err_t tcp_process(struct tcp_pcb *pcb);
segundo	0:ac1725ba162c	76	static void tcp_receive(struct tcp_pcb *pcb);
segundo	0:ac1725ba162c	77	static void tcp_parseopt(struct tcp_pcb *pcb);
segundo	0:ac1725ba162c	78
segundo	0:ac1725ba162c	79	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
segundo	0:ac1725ba162c	80	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
segundo	0:ac1725ba162c	81
segundo	0:ac1725ba162c	82	/**
segundo	0:ac1725ba162c	83	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
segundo	0:ac1725ba162c	84	* the segment between the PCBs and passes it on to tcp_process(), which implements
segundo	0:ac1725ba162c	85	* the TCP finite state machine. This function is called by the IP layer (in
segundo	0:ac1725ba162c	86	* ip_input()).
segundo	0:ac1725ba162c	87	*
segundo	0:ac1725ba162c	88	* @param p received TCP segment to process (p->payload pointing to the IP header)
segundo	0:ac1725ba162c	89	* @param inp network interface on which this segment was received
segundo	0:ac1725ba162c	90	*/
segundo	0:ac1725ba162c	91	void
segundo	0:ac1725ba162c	92	tcp_input(struct pbuf p, struct netif inp)
segundo	0:ac1725ba162c	93	{
segundo	0:ac1725ba162c	94	struct tcp_pcb pcb, prev;
segundo	0:ac1725ba162c	95	struct tcp_pcb_listen *lpcb;
segundo	0:ac1725ba162c	96	#if SO_REUSE
segundo	0:ac1725ba162c	97	struct tcp_pcb *lpcb_prev = NULL;
segundo	0:ac1725ba162c	98	struct tcp_pcb_listen *lpcb_any = NULL;
segundo	0:ac1725ba162c	99	#endif /* SO_REUSE */
segundo	0:ac1725ba162c	100	u8_t hdrlen;
segundo	0:ac1725ba162c	101	err_t err;
segundo	0:ac1725ba162c	102
segundo	0:ac1725ba162c	103	PERF_START;
segundo	0:ac1725ba162c	104
segundo	0:ac1725ba162c	105	TCP_STATS_INC(tcp.recv);
segundo	0:ac1725ba162c	106	snmp_inc_tcpinsegs();
segundo	0:ac1725ba162c	107
segundo	0:ac1725ba162c	108	iphdr = (struct ip_hdr *)p->payload;
segundo	0:ac1725ba162c	109	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
segundo	0:ac1725ba162c	110
segundo	0:ac1725ba162c	111	#if TCP_INPUT_DEBUG
segundo	0:ac1725ba162c	112	tcp_debug_print(tcphdr);
segundo	0:ac1725ba162c	113	#endif
segundo	0:ac1725ba162c	114
segundo	0:ac1725ba162c	115	/* remove header from payload */
segundo	0:ac1725ba162c	116	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
segundo	0:ac1725ba162c	117	/* drop short packets */
segundo	0:ac1725ba162c	118	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
segundo	0:ac1725ba162c	119	TCP_STATS_INC(tcp.lenerr);
segundo	0:ac1725ba162c	120	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	121	snmp_inc_tcpinerrs();
segundo	0:ac1725ba162c	122	pbuf_free(p);
segundo	0:ac1725ba162c	123	return;
segundo	0:ac1725ba162c	124	}
segundo	0:ac1725ba162c	125
segundo	0:ac1725ba162c	126	/* Don't even process incoming broadcasts/multicasts. */
segundo	0:ac1725ba162c	127	if (ip_addr_isbroadcast(&current_iphdr_dest, inp) \|\|
segundo	0:ac1725ba162c	128	ip_addr_ismulticast(&current_iphdr_dest)) {
segundo	0:ac1725ba162c	129	TCP_STATS_INC(tcp.proterr);
segundo	0:ac1725ba162c	130	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	131	snmp_inc_tcpinerrs();
segundo	0:ac1725ba162c	132	pbuf_free(p);
segundo	0:ac1725ba162c	133	return;
segundo	0:ac1725ba162c	134	}
segundo	0:ac1725ba162c	135
segundo	0:ac1725ba162c	136	#if CHECKSUM_CHECK_TCP
segundo	0:ac1725ba162c	137	/* Verify TCP checksum. */
segundo	0:ac1725ba162c	138	if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
segundo	0:ac1725ba162c	139	IP_PROTO_TCP, p->tot_len) != 0) {
segundo	0:ac1725ba162c	140	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
segundo	0:ac1725ba162c	141	inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
segundo	0:ac1725ba162c	142	IP_PROTO_TCP, p->tot_len)));
segundo	0:ac1725ba162c	143	#if TCP_DEBUG
segundo	0:ac1725ba162c	144	tcp_debug_print(tcphdr);
segundo	0:ac1725ba162c	145	#endif /* TCP_DEBUG */
segundo	0:ac1725ba162c	146	TCP_STATS_INC(tcp.chkerr);
segundo	0:ac1725ba162c	147	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	148	snmp_inc_tcpinerrs();
segundo	0:ac1725ba162c	149	pbuf_free(p);
segundo	0:ac1725ba162c	150	return;
segundo	0:ac1725ba162c	151	}
segundo	0:ac1725ba162c	152	#endif
segundo	0:ac1725ba162c	153
segundo	0:ac1725ba162c	154	/* Move the payload pointer in the pbuf so that it points to the
segundo	0:ac1725ba162c	155	TCP data instead of the TCP header. */
segundo	0:ac1725ba162c	156	hdrlen = TCPH_HDRLEN(tcphdr);
segundo	0:ac1725ba162c	157	if(pbuf_header(p, -(hdrlen * 4))){
segundo	0:ac1725ba162c	158	/* drop short packets */
segundo	0:ac1725ba162c	159	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
segundo	0:ac1725ba162c	160	TCP_STATS_INC(tcp.lenerr);
segundo	0:ac1725ba162c	161	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	162	snmp_inc_tcpinerrs();
segundo	0:ac1725ba162c	163	pbuf_free(p);
segundo	0:ac1725ba162c	164	return;
segundo	0:ac1725ba162c	165	}
segundo	0:ac1725ba162c	166
segundo	0:ac1725ba162c	167	/* Convert fields in TCP header to host byte order. */
segundo	0:ac1725ba162c	168	tcphdr->src = ntohs(tcphdr->src);
segundo	0:ac1725ba162c	169	tcphdr->dest = ntohs(tcphdr->dest);
segundo	0:ac1725ba162c	170	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
segundo	0:ac1725ba162c	171	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
segundo	0:ac1725ba162c	172	tcphdr->wnd = ntohs(tcphdr->wnd);
segundo	0:ac1725ba162c	173
segundo	0:ac1725ba162c	174	flags = TCPH_FLAGS(tcphdr);
segundo	0:ac1725ba162c	175	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
segundo	0:ac1725ba162c	176
segundo	0:ac1725ba162c	177	/* Demultiplex an incoming segment. First, we check if it is destined
segundo	0:ac1725ba162c	178	for an active connection. */
segundo	0:ac1725ba162c	179	prev = NULL;
segundo	0:ac1725ba162c	180
segundo	0:ac1725ba162c	181
segundo	0:ac1725ba162c	182	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
segundo	0:ac1725ba162c	183	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
segundo	0:ac1725ba162c	184	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
segundo	0:ac1725ba162c	185	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
segundo	0:ac1725ba162c	186	if (pcb->remote_port == tcphdr->src &&
segundo	0:ac1725ba162c	187	pcb->local_port == tcphdr->dest &&
segundo	0:ac1725ba162c	188	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
segundo	0:ac1725ba162c	189	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
segundo	0:ac1725ba162c	190
segundo	0:ac1725ba162c	191	/* Move this PCB to the front of the list so that subsequent
segundo	0:ac1725ba162c	192	lookups will be faster (we exploit locality in TCP segment
segundo	0:ac1725ba162c	193	arrivals). */
segundo	0:ac1725ba162c	194	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
segundo	0:ac1725ba162c	195	if (prev != NULL) {
segundo	0:ac1725ba162c	196	prev->next = pcb->next;
segundo	0:ac1725ba162c	197	pcb->next = tcp_active_pcbs;
segundo	0:ac1725ba162c	198	tcp_active_pcbs = pcb;
segundo	0:ac1725ba162c	199	}
segundo	0:ac1725ba162c	200	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
segundo	0:ac1725ba162c	201	break;
segundo	0:ac1725ba162c	202	}
segundo	0:ac1725ba162c	203	prev = pcb;
segundo	0:ac1725ba162c	204	}
segundo	0:ac1725ba162c	205
segundo	0:ac1725ba162c	206	if (pcb == NULL) {
segundo	0:ac1725ba162c	207	/* If it did not go to an active connection, we check the connections
segundo	0:ac1725ba162c	208	in the TIME-WAIT state. */
segundo	0:ac1725ba162c	209	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
segundo	0:ac1725ba162c	210	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
segundo	0:ac1725ba162c	211	if (pcb->remote_port == tcphdr->src &&
segundo	0:ac1725ba162c	212	pcb->local_port == tcphdr->dest &&
segundo	0:ac1725ba162c	213	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
segundo	0:ac1725ba162c	214	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
segundo	0:ac1725ba162c	215	/* We don't really care enough to move this PCB to the front
segundo	0:ac1725ba162c	216	of the list since we are not very likely to receive that
segundo	0:ac1725ba162c	217	many segments for connections in TIME-WAIT. */
segundo	0:ac1725ba162c	218	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
segundo	0:ac1725ba162c	219	tcp_timewait_input(pcb);
segundo	0:ac1725ba162c	220	pbuf_free(p);
segundo	0:ac1725ba162c	221	return;
segundo	0:ac1725ba162c	222	}
segundo	0:ac1725ba162c	223	}
segundo	0:ac1725ba162c	224
segundo	0:ac1725ba162c	225	/* Finally, if we still did not get a match, we check all PCBs that
segundo	0:ac1725ba162c	226	are LISTENing for incoming connections. */
segundo	0:ac1725ba162c	227	prev = NULL;
segundo	0:ac1725ba162c	228	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
segundo	0:ac1725ba162c	229	if (lpcb->local_port == tcphdr->dest) {
segundo	0:ac1725ba162c	230	#if SO_REUSE
segundo	0:ac1725ba162c	231	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
segundo	0:ac1725ba162c	232	/* found an exact match */
segundo	0:ac1725ba162c	233	break;
segundo	0:ac1725ba162c	234	} else if(ip_addr_isany(&(lpcb->local_ip))) {
segundo	0:ac1725ba162c	235	/* found an ANY-match */
segundo	0:ac1725ba162c	236	lpcb_any = lpcb;
segundo	0:ac1725ba162c	237	lpcb_prev = prev;
segundo	0:ac1725ba162c	238	}
segundo	0:ac1725ba162c	239	#else /* SO_REUSE */
segundo	0:ac1725ba162c	240	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) \|\|
segundo	0:ac1725ba162c	241	ip_addr_isany(&(lpcb->local_ip))) {
segundo	0:ac1725ba162c	242	/* found a match */
segundo	0:ac1725ba162c	243	break;
segundo	0:ac1725ba162c	244	}
segundo	0:ac1725ba162c	245	#endif /* SO_REUSE */
segundo	0:ac1725ba162c	246	}
segundo	0:ac1725ba162c	247	prev = (struct tcp_pcb *)lpcb;
segundo	0:ac1725ba162c	248	}
segundo	0:ac1725ba162c	249	#if SO_REUSE
segundo	0:ac1725ba162c	250	/* first try specific local IP */
segundo	0:ac1725ba162c	251	if (lpcb == NULL) {
segundo	0:ac1725ba162c	252	/* only pass to ANY if no specific local IP has been found */
segundo	0:ac1725ba162c	253	lpcb = lpcb_any;
segundo	0:ac1725ba162c	254	prev = lpcb_prev;
segundo	0:ac1725ba162c	255	}
segundo	0:ac1725ba162c	256	#endif /* SO_REUSE */
segundo	0:ac1725ba162c	257	if (lpcb != NULL) {
segundo	0:ac1725ba162c	258	/* Move this PCB to the front of the list so that subsequent
segundo	0:ac1725ba162c	259	lookups will be faster (we exploit locality in TCP segment
segundo	0:ac1725ba162c	260	arrivals). */
segundo	0:ac1725ba162c	261	if (prev != NULL) {
segundo	0:ac1725ba162c	262	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
segundo	0:ac1725ba162c	263	/* our successor is the remainder of the listening list */
segundo	0:ac1725ba162c	264	lpcb->next = tcp_listen_pcbs.listen_pcbs;
segundo	0:ac1725ba162c	265	/* put this listening pcb at the head of the listening list */
segundo	0:ac1725ba162c	266	tcp_listen_pcbs.listen_pcbs = lpcb;
segundo	0:ac1725ba162c	267	}
segundo	0:ac1725ba162c	268
segundo	0:ac1725ba162c	269	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
segundo	0:ac1725ba162c	270	tcp_listen_input(lpcb);
segundo	0:ac1725ba162c	271	pbuf_free(p);
segundo	0:ac1725ba162c	272	return;
segundo	0:ac1725ba162c	273	}
segundo	0:ac1725ba162c	274	}
segundo	0:ac1725ba162c	275
segundo	0:ac1725ba162c	276	#if TCP_INPUT_DEBUG
segundo	0:ac1725ba162c	277	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
segundo	0:ac1725ba162c	278	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
segundo	0:ac1725ba162c	279	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
segundo	0:ac1725ba162c	280	#endif /* TCP_INPUT_DEBUG */
segundo	0:ac1725ba162c	281
segundo	0:ac1725ba162c	282
segundo	0:ac1725ba162c	283	if (pcb != NULL) {
segundo	0:ac1725ba162c	284	/* The incoming segment belongs to a connection. */
segundo	0:ac1725ba162c	285	#if TCP_INPUT_DEBUG
segundo	0:ac1725ba162c	286	#if TCP_DEBUG
segundo	0:ac1725ba162c	287	tcp_debug_print_state(pcb->state);
segundo	0:ac1725ba162c	288	#endif /* TCP_DEBUG */
segundo	0:ac1725ba162c	289	#endif /* TCP_INPUT_DEBUG */
segundo	0:ac1725ba162c	290
segundo	0:ac1725ba162c	291	/* Set up a tcp_seg structure. */
segundo	0:ac1725ba162c	292	inseg.next = NULL;
segundo	0:ac1725ba162c	293	inseg.len = p->tot_len;
segundo	0:ac1725ba162c	294	inseg.dataptr = p->payload;
segundo	0:ac1725ba162c	295	inseg.p = p;
segundo	0:ac1725ba162c	296	inseg.tcphdr = tcphdr;
segundo	0:ac1725ba162c	297
segundo	0:ac1725ba162c	298	recv_data = NULL;
segundo	0:ac1725ba162c	299	recv_flags = 0;
segundo	0:ac1725ba162c	300
segundo	0:ac1725ba162c	301	/* If there is data which was previously "refused" by upper layer */
segundo	0:ac1725ba162c	302	if (pcb->refused_data != NULL) {
segundo	0:ac1725ba162c	303	/* Notify again application with data previously received. */
segundo	0:ac1725ba162c	304	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
segundo	0:ac1725ba162c	305	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
segundo	0:ac1725ba162c	306	if (err == ERR_OK) {
segundo	0:ac1725ba162c	307	pcb->refused_data = NULL;
segundo	0:ac1725ba162c	308	} else {
segundo	0:ac1725ba162c	309	/* if err == ERR_ABRT, 'pcb' is already deallocated */
segundo	0:ac1725ba162c	310	/* drop incoming packets, because pcb is "full" */
segundo	0:ac1725ba162c	311	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
segundo	0:ac1725ba162c	312	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	313	snmp_inc_tcpinerrs();
segundo	0:ac1725ba162c	314	pbuf_free(p);
segundo	0:ac1725ba162c	315	return;
segundo	0:ac1725ba162c	316	}
segundo	0:ac1725ba162c	317	}
segundo	0:ac1725ba162c	318	tcp_input_pcb = pcb;
segundo	0:ac1725ba162c	319	err = tcp_process(pcb);
segundo	0:ac1725ba162c	320	/* A return value of ERR_ABRT means that tcp_abort() was called
segundo	0:ac1725ba162c	321	and that the pcb has been freed. If so, we don't do anything. */
segundo	0:ac1725ba162c	322	if (err != ERR_ABRT) {
segundo	0:ac1725ba162c	323	if (recv_flags & TF_RESET) {
segundo	0:ac1725ba162c	324	/* TF_RESET means that the connection was reset by the other
segundo	0:ac1725ba162c	325	end. We then call the error callback to inform the
segundo	0:ac1725ba162c	326	application that the connection is dead before we
segundo	0:ac1725ba162c	327	deallocate the PCB. */
segundo	0:ac1725ba162c	328	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
segundo	0:ac1725ba162c	329	tcp_pcb_remove(&tcp_active_pcbs, pcb);
segundo	0:ac1725ba162c	330	memp_free(MEMP_TCP_PCB, pcb);
segundo	0:ac1725ba162c	331	} else if (recv_flags & TF_CLOSED) {
segundo	0:ac1725ba162c	332	/* The connection has been closed and we will deallocate the
segundo	0:ac1725ba162c	333	PCB. */
segundo	0:ac1725ba162c	334	tcp_pcb_remove(&tcp_active_pcbs, pcb);
segundo	0:ac1725ba162c	335	memp_free(MEMP_TCP_PCB, pcb);
segundo	0:ac1725ba162c	336	} else {
segundo	0:ac1725ba162c	337	err = ERR_OK;
segundo	0:ac1725ba162c	338	/* If the application has registered a "sent" function to be
segundo	0:ac1725ba162c	339	called when new send buffer space is available, we call it
segundo	0:ac1725ba162c	340	now. */
segundo	0:ac1725ba162c	341	if (pcb->acked > 0) {
segundo	0:ac1725ba162c	342	TCP_EVENT_SENT(pcb, pcb->acked, err);
segundo	0:ac1725ba162c	343	if (err == ERR_ABRT) {
segundo	0:ac1725ba162c	344	goto aborted;
segundo	0:ac1725ba162c	345	}
segundo	0:ac1725ba162c	346	}
segundo	0:ac1725ba162c	347
segundo	0:ac1725ba162c	348	if (recv_data != NULL) {
segundo	0:ac1725ba162c	349	if (pcb->flags & TF_RXCLOSED) {
segundo	0:ac1725ba162c	350	/* received data although already closed -> abort (send RST) to
segundo	0:ac1725ba162c	351	notify the remote host that not all data has been processed */
segundo	0:ac1725ba162c	352	pbuf_free(recv_data);
segundo	0:ac1725ba162c	353	tcp_abort(pcb);
segundo	0:ac1725ba162c	354	goto aborted;
segundo	0:ac1725ba162c	355	}
segundo	0:ac1725ba162c	356	if (flags & TCP_PSH) {
segundo	0:ac1725ba162c	357	recv_data->flags \|= PBUF_FLAG_PUSH;
segundo	0:ac1725ba162c	358	}
segundo	0:ac1725ba162c	359
segundo	0:ac1725ba162c	360	/* Notify application that data has been received. */
segundo	0:ac1725ba162c	361	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
segundo	0:ac1725ba162c	362	if (err == ERR_ABRT) {
segundo	0:ac1725ba162c	363	goto aborted;
segundo	0:ac1725ba162c	364	}
segundo	0:ac1725ba162c	365
segundo	0:ac1725ba162c	366	/* If the upper layer can't receive this data, store it */
segundo	0:ac1725ba162c	367	if (err != ERR_OK) {
segundo	0:ac1725ba162c	368	pcb->refused_data = recv_data;
segundo	0:ac1725ba162c	369	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
segundo	0:ac1725ba162c	370	}
segundo	0:ac1725ba162c	371	}
segundo	0:ac1725ba162c	372
segundo	0:ac1725ba162c	373	/* If a FIN segment was received, we call the callback
segundo	0:ac1725ba162c	374	function with a NULL buffer to indicate EOF. */
segundo	0:ac1725ba162c	375	if (recv_flags & TF_GOT_FIN) {
segundo	0:ac1725ba162c	376	/* correct rcv_wnd as the application won't call tcp_recved()
segundo	0:ac1725ba162c	377	for the FIN's seqno */
segundo	0:ac1725ba162c	378	if (pcb->rcv_wnd != TCP_WND) {
segundo	0:ac1725ba162c	379	pcb->rcv_wnd++;
segundo	0:ac1725ba162c	380	}
segundo	0:ac1725ba162c	381	TCP_EVENT_CLOSED(pcb, err);
segundo	0:ac1725ba162c	382	if (err == ERR_ABRT) {
segundo	0:ac1725ba162c	383	goto aborted;
segundo	0:ac1725ba162c	384	}
segundo	0:ac1725ba162c	385	}
segundo	0:ac1725ba162c	386
segundo	0:ac1725ba162c	387	tcp_input_pcb = NULL;
segundo	0:ac1725ba162c	388	/* Try to send something out. */
segundo	0:ac1725ba162c	389	tcp_output(pcb);
segundo	0:ac1725ba162c	390	#if TCP_INPUT_DEBUG
segundo	0:ac1725ba162c	391	#if TCP_DEBUG
segundo	0:ac1725ba162c	392	tcp_debug_print_state(pcb->state);
segundo	0:ac1725ba162c	393	#endif /* TCP_DEBUG */
segundo	0:ac1725ba162c	394	#endif /* TCP_INPUT_DEBUG */
segundo	0:ac1725ba162c	395	}
segundo	0:ac1725ba162c	396	}
segundo	0:ac1725ba162c	397	/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
segundo	0:ac1725ba162c	398	Below this line, 'pcb' may not be dereferenced! */
segundo	0:ac1725ba162c	399	aborted:
segundo	0:ac1725ba162c	400	tcp_input_pcb = NULL;
segundo	0:ac1725ba162c	401	recv_data = NULL;
segundo	0:ac1725ba162c	402
segundo	0:ac1725ba162c	403	/* give up our reference to inseg.p */
segundo	0:ac1725ba162c	404	if (inseg.p != NULL)
segundo	0:ac1725ba162c	405	{
segundo	0:ac1725ba162c	406	pbuf_free(inseg.p);
segundo	0:ac1725ba162c	407	inseg.p = NULL;
segundo	0:ac1725ba162c	408	}
segundo	0:ac1725ba162c	409	} else {
segundo	0:ac1725ba162c	410
segundo	0:ac1725ba162c	411	/* If no matching PCB was found, send a TCP RST (reset) to the
segundo	0:ac1725ba162c	412	sender. */
segundo	0:ac1725ba162c	413	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
segundo	0:ac1725ba162c	414	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
segundo	0:ac1725ba162c	415	TCP_STATS_INC(tcp.proterr);
segundo	0:ac1725ba162c	416	TCP_STATS_INC(tcp.drop);
segundo	0:ac1725ba162c	417	tcp_rst(ackno, seqno + tcplen,
segundo	0:ac1725ba162c	418	ip_current_dest_addr(), ip_current_src_addr(),
segundo	0:ac1725ba162c	419	tcphdr->dest, tcphdr->src);
segundo	0:ac1725ba162c	420	}
segundo	0:ac1725ba162c	421	pbuf_free(p);
segundo	0:ac1725ba162c	422	}
segundo	0:ac1725ba162c	423
segundo	0:ac1725ba162c	424	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
segundo	0:ac1725ba162c	425	PERF_STOP("tcp_input");
segundo	0:ac1725ba162c	426	}
segundo	0:ac1725ba162c	427
segundo	0:ac1725ba162c	428	/**
segundo	0:ac1725ba162c	429	* Called by tcp_input() when a segment arrives for a listening
segundo	0:ac1725ba162c	430	* connection (from tcp_input()).
segundo	0:ac1725ba162c	431	*
segundo	0:ac1725ba162c	432	* @param pcb the tcp_pcb_listen for which a segment arrived
segundo	0:ac1725ba162c	433	* @return ERR_OK if the segment was processed
segundo	0:ac1725ba162c	434	* another err_t on error
segundo	0:ac1725ba162c	435	*
segundo	0:ac1725ba162c	436	* @note the return value is not (yet?) used in tcp_input()
segundo	0:ac1725ba162c	437	* @note the segment which arrived is saved in global variables, therefore only the pcb
segundo	0:ac1725ba162c	438	* involved is passed as a parameter to this function
segundo	0:ac1725ba162c	439	*/
segundo	0:ac1725ba162c	440	static err_t
segundo	0:ac1725ba162c	441	tcp_listen_input(struct tcp_pcb_listen *pcb)
segundo	0:ac1725ba162c	442	{
segundo	0:ac1725ba162c	443	struct tcp_pcb *npcb;
segundo	0:ac1725ba162c	444	err_t rc;
segundo	0:ac1725ba162c	445
segundo	0:ac1725ba162c	446	/* In the LISTEN state, we check for incoming SYN segments,
segundo	0:ac1725ba162c	447	creates a new PCB, and responds with a SYN\|ACK. */
segundo	0:ac1725ba162c	448	if (flags & TCP_ACK) {
segundo	0:ac1725ba162c	449	/* For incoming segments with the ACK flag set, respond with a
segundo	0:ac1725ba162c	450	RST. */
segundo	0:ac1725ba162c	451	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
segundo	0:ac1725ba162c	452	tcp_rst(ackno + 1, seqno + tcplen,
segundo	0:ac1725ba162c	453	ip_current_dest_addr(), ip_current_src_addr(),
segundo	0:ac1725ba162c	454	tcphdr->dest, tcphdr->src);
segundo	0:ac1725ba162c	455	} else if (flags & TCP_SYN) {
segundo	0:ac1725ba162c	456	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
segundo	0:ac1725ba162c	457	#if TCP_LISTEN_BACKLOG
segundo	0:ac1725ba162c	458	if (pcb->accepts_pending >= pcb->backlog) {
segundo	0:ac1725ba162c	459	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
segundo	0:ac1725ba162c	460	return ERR_ABRT;
segundo	0:ac1725ba162c	461	}
segundo	0:ac1725ba162c	462	#endif /* TCP_LISTEN_BACKLOG */
segundo	0:ac1725ba162c	463	npcb = tcp_alloc(pcb->prio);
segundo	0:ac1725ba162c	464	/* If a new PCB could not be created (probably due to lack of memory),
segundo	0:ac1725ba162c	465	we don't do anything, but rely on the sender will retransmit the
segundo	0:ac1725ba162c	466	SYN at a time when we have more memory available. */
segundo	0:ac1725ba162c	467	if (npcb == NULL) {
segundo	0:ac1725ba162c	468	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
segundo	0:ac1725ba162c	469	TCP_STATS_INC(tcp.memerr);
segundo	0:ac1725ba162c	470	return ERR_MEM;
segundo	0:ac1725ba162c	471	}
segundo	0:ac1725ba162c	472	#if TCP_LISTEN_BACKLOG
segundo	0:ac1725ba162c	473	pcb->accepts_pending++;
segundo	0:ac1725ba162c	474	#endif /* TCP_LISTEN_BACKLOG */
segundo	0:ac1725ba162c	475	/* Set up the new PCB. */
segundo	0:ac1725ba162c	476	ip_addr_copy(npcb->local_ip, current_iphdr_dest);
segundo	0:ac1725ba162c	477	npcb->local_port = pcb->local_port;
segundo	0:ac1725ba162c	478	ip_addr_copy(npcb->remote_ip, current_iphdr_src);
segundo	0:ac1725ba162c	479	npcb->remote_port = tcphdr->src;
segundo	0:ac1725ba162c	480	npcb->state = SYN_RCVD;
segundo	0:ac1725ba162c	481	npcb->rcv_nxt = seqno + 1;
segundo	0:ac1725ba162c	482	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
segundo	0:ac1725ba162c	483	npcb->snd_wnd = tcphdr->wnd;
segundo	0:ac1725ba162c	484	npcb->ssthresh = npcb->snd_wnd;
segundo	0:ac1725ba162c	485	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
segundo	0:ac1725ba162c	486	npcb->callback_arg = pcb->callback_arg;
segundo	0:ac1725ba162c	487	#if LWIP_CALLBACK_API
segundo	0:ac1725ba162c	488	npcb->accept = pcb->accept;
segundo	0:ac1725ba162c	489	#endif /* LWIP_CALLBACK_API */
segundo	0:ac1725ba162c	490	/* inherit socket options */
segundo	0:ac1725ba162c	491	npcb->so_options = pcb->so_options & SOF_INHERITED;
segundo	0:ac1725ba162c	492	/* Register the new PCB so that we can begin receiving segments
segundo	0:ac1725ba162c	493	for it. */
segundo	0:ac1725ba162c	494	TCP_REG(&tcp_active_pcbs, npcb);
segundo	0:ac1725ba162c	495
segundo	0:ac1725ba162c	496	/* Parse any options in the SYN. */
segundo	0:ac1725ba162c	497	tcp_parseopt(npcb);
segundo	0:ac1725ba162c	498	#if TCP_CALCULATE_EFF_SEND_MSS
segundo	0:ac1725ba162c	499	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
segundo	0:ac1725ba162c	500	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
segundo	0:ac1725ba162c	501
segundo	0:ac1725ba162c	502	snmp_inc_tcppassiveopens();
segundo	0:ac1725ba162c	503
segundo	0:ac1725ba162c	504	/* Send a SYN\|ACK together with the MSS option. */
segundo	0:ac1725ba162c	505	rc = tcp_enqueue_flags(npcb, TCP_SYN \| TCP_ACK);
segundo	0:ac1725ba162c	506	if (rc != ERR_OK) {
segundo	0:ac1725ba162c	507	tcp_abandon(npcb, 0);
segundo	0:ac1725ba162c	508	return rc;
segundo	0:ac1725ba162c	509	}
segundo	0:ac1725ba162c	510	return tcp_output(npcb);
segundo	0:ac1725ba162c	511	}
segundo	0:ac1725ba162c	512	return ERR_OK;
segundo	0:ac1725ba162c	513	}
segundo	0:ac1725ba162c	514
segundo	0:ac1725ba162c	515	/**
segundo	0:ac1725ba162c	516	* Called by tcp_input() when a segment arrives for a connection in
segundo	0:ac1725ba162c	517	* TIME_WAIT.
segundo	0:ac1725ba162c	518	*
segundo	0:ac1725ba162c	519	* @param pcb the tcp_pcb for which a segment arrived
segundo	0:ac1725ba162c	520	*
segundo	0:ac1725ba162c	521	* @note the segment which arrived is saved in global variables, therefore only the pcb
segundo	0:ac1725ba162c	522	* involved is passed as a parameter to this function
segundo	0:ac1725ba162c	523	*/
segundo	0:ac1725ba162c	524	static err_t
segundo	0:ac1725ba162c	525	tcp_timewait_input(struct tcp_pcb *pcb)
segundo	0:ac1725ba162c	526	{
segundo	0:ac1725ba162c	527	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
segundo	0:ac1725ba162c	528	/* RFC 793 3.9 Event Processing - Segment Arrives:
segundo	0:ac1725ba162c	529	* - first check sequence number - we skip that one in TIME_WAIT (always
segundo	0:ac1725ba162c	530	* acceptable since we only send ACKs)
segundo	0:ac1725ba162c	531	* - second check the RST bit (... return) */
segundo	0:ac1725ba162c	532	if (flags & TCP_RST) {
segundo	0:ac1725ba162c	533	return ERR_OK;
segundo	0:ac1725ba162c	534	}
segundo	0:ac1725ba162c	535	/* - fourth, check the SYN bit, */
segundo	0:ac1725ba162c	536	if (flags & TCP_SYN) {
segundo	0:ac1725ba162c	537	/* If an incoming segment is not acceptable, an acknowledgment
segundo	0:ac1725ba162c	538	should be sent in reply */
segundo	0:ac1725ba162c	539	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
segundo	0:ac1725ba162c	540	/* If the SYN is in the window it is an error, send a reset */
segundo	0:ac1725ba162c	541	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
segundo	0:ac1725ba162c	542	tcphdr->dest, tcphdr->src);
segundo	0:ac1725ba162c	543	return ERR_OK;
segundo	0:ac1725ba162c	544	}
segundo	0:ac1725ba162c	545	} else if (flags & TCP_FIN) {
segundo	0:ac1725ba162c	546	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
segundo	0:ac1725ba162c	547	Restart the 2 MSL time-wait timeout.*/
segundo	0:ac1725ba162c	548	pcb->tmr = tcp_ticks;
segundo	0:ac1725ba162c	549	}
segundo	0:ac1725ba162c	550
segundo	0:ac1725ba162c	551	if ((tcplen > 0)) {
segundo	0:ac1725ba162c	552	/* Acknowledge data, FIN or out-of-window SYN */
segundo	0:ac1725ba162c	553	pcb->flags \|= TF_ACK_NOW;
segundo	0:ac1725ba162c	554	return tcp_output(pcb);
segundo	0:ac1725ba162c	555	}
segundo	0:ac1725ba162c	556	return ERR_OK;
segundo	0:ac1725ba162c	557	}
segundo	0:ac1725ba162c	558
segundo	0:ac1725ba162c	559	/**
segundo	0:ac1725ba162c	560	* Implements the TCP state machine. Called by tcp_input. In some
segundo	0:ac1725ba162c	561	* states tcp_receive() is called to receive data. The tcp_seg
segundo	0:ac1725ba162c	562	* argument will be freed by the caller (tcp_input()) unless the
segundo	0:ac1725ba162c	563	* recv_data pointer in the pcb is set.
segundo	0:ac1725ba162c	564	*
segundo	0:ac1725ba162c	565	* @param pcb the tcp_pcb for which a segment arrived
segundo	0:ac1725ba162c	566	*
segundo	0:ac1725ba162c	567	* @note the segment which arrived is saved in global variables, therefore only the pcb
segundo	0:ac1725ba162c	568	* involved is passed as a parameter to this function
segundo	0:ac1725ba162c	569	*/
segundo	0:ac1725ba162c	570	static err_t
segundo	0:ac1725ba162c	571	tcp_process(struct tcp_pcb *pcb)
segundo	0:ac1725ba162c	572	{
segundo	0:ac1725ba162c	573	struct tcp_seg *rseg;
segundo	0:ac1725ba162c	574	u8_t acceptable = 0;
segundo	0:ac1725ba162c	575	err_t err;
segundo	0:ac1725ba162c	576
segundo	0:ac1725ba162c	577	err = ERR_OK;
segundo	0:ac1725ba162c	578
segundo	0:ac1725ba162c	579	/* Process incoming RST segments. */
segundo	0:ac1725ba162c	580	if (flags & TCP_RST) {
segundo	0:ac1725ba162c	581	/* First, determine if the reset is acceptable. */
segundo	0:ac1725ba162c	582	if (pcb->state == SYN_SENT) {
segundo	0:ac1725ba162c	583	if (ackno == pcb->snd_nxt) {
segundo	0:ac1725ba162c	584	acceptable = 1;
segundo	0:ac1725ba162c	585	}
segundo	0:ac1725ba162c	586	} else {
segundo	0:ac1725ba162c	587	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
segundo	0:ac1725ba162c	588	pcb->rcv_nxt+pcb->rcv_wnd)) {
segundo	0:ac1725ba162c	589	acceptable = 1;
segundo	0:ac1725ba162c	590	}
segundo	0:ac1725ba162c	591	}
segundo	0:ac1725ba162c	592
segundo	0:ac1725ba162c	593	if (acceptable) {
segundo	0:ac1725ba162c	594	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
segundo	0:ac1725ba162c	595	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
segundo	0:ac1725ba162c	596	recv_flags \|= TF_RESET;
segundo	0:ac1725ba162c	597	pcb->flags &= ~TF_ACK_DELAY;
segundo	0:ac1725ba162c	598	return ERR_RST;
segundo	0:ac1725ba162c	599	} else {
segundo	0:ac1725ba162c	600	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
segundo	0:ac1725ba162c	601	seqno, pcb->rcv_nxt));
segundo	0:ac1725ba162c	602	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
segundo	0:ac1725ba162c	603	seqno, pcb->rcv_nxt));
segundo	0:ac1725ba162c	604	return ERR_OK;
segundo	0:ac1725ba162c	605	}
segundo	0:ac1725ba162c	606	}
segundo	0:ac1725ba162c	607
segundo	0:ac1725ba162c	608	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
segundo	0:ac1725ba162c	609	/* Cope with new connection attempt after remote end crashed */
segundo	0:ac1725ba162c	610	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	611	return ERR_OK;
segundo	0:ac1725ba162c	612	}
segundo	0:ac1725ba162c	613
segundo	0:ac1725ba162c	614	if ((pcb->flags & TF_RXCLOSED) == 0) {
segundo	0:ac1725ba162c	615	/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
segundo	0:ac1725ba162c	616	pcb->tmr = tcp_ticks;
segundo	0:ac1725ba162c	617	}
segundo	0:ac1725ba162c	618	pcb->keep_cnt_sent = 0;
segundo	0:ac1725ba162c	619
segundo	0:ac1725ba162c	620	tcp_parseopt(pcb);
segundo	0:ac1725ba162c	621
segundo	0:ac1725ba162c	622	/* Do different things depending on the TCP state. */
segundo	0:ac1725ba162c	623	switch (pcb->state) {
segundo	0:ac1725ba162c	624	case SYN_SENT:
segundo	0:ac1725ba162c	625	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
segundo	0:ac1725ba162c	626	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
segundo	0:ac1725ba162c	627	/* received SYN ACK with expected sequence number? */
segundo	0:ac1725ba162c	628	if ((flags & TCP_ACK) && (flags & TCP_SYN)
segundo	0:ac1725ba162c	629	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
segundo	0:ac1725ba162c	630	pcb->snd_buf++;
segundo	0:ac1725ba162c	631	pcb->rcv_nxt = seqno + 1;
segundo	0:ac1725ba162c	632	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
segundo	0:ac1725ba162c	633	pcb->lastack = ackno;
segundo	0:ac1725ba162c	634	pcb->snd_wnd = tcphdr->wnd;
segundo	0:ac1725ba162c	635	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
segundo	0:ac1725ba162c	636	pcb->state = ESTABLISHED;
segundo	0:ac1725ba162c	637
segundo	0:ac1725ba162c	638	#if TCP_CALCULATE_EFF_SEND_MSS
segundo	0:ac1725ba162c	639	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
segundo	0:ac1725ba162c	640	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
segundo	0:ac1725ba162c	641
segundo	0:ac1725ba162c	642	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
segundo	0:ac1725ba162c	643	* but for the default value of pcb->mss) */
segundo	0:ac1725ba162c	644	pcb->ssthresh = pcb->mss * 10;
segundo	0:ac1725ba162c	645
segundo	0:ac1725ba162c	646	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
segundo	0:ac1725ba162c	647	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
segundo	0:ac1725ba162c	648	--pcb->snd_queuelen;
segundo	0:ac1725ba162c	649	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
segundo	0:ac1725ba162c	650	rseg = pcb->unacked;
segundo	0:ac1725ba162c	651	pcb->unacked = rseg->next;
segundo	0:ac1725ba162c	652
segundo	0:ac1725ba162c	653	/* If there's nothing left to acknowledge, stop the retransmit
segundo	0:ac1725ba162c	654	timer, otherwise reset it to start again */
segundo	0:ac1725ba162c	655	if(pcb->unacked == NULL)
segundo	0:ac1725ba162c	656	pcb->rtime = -1;
segundo	0:ac1725ba162c	657	else {
segundo	0:ac1725ba162c	658	pcb->rtime = 0;
segundo	0:ac1725ba162c	659	pcb->nrtx = 0;
segundo	0:ac1725ba162c	660	}
segundo	0:ac1725ba162c	661
segundo	0:ac1725ba162c	662	tcp_seg_free(rseg);
segundo	0:ac1725ba162c	663
segundo	0:ac1725ba162c	664	/* Call the user specified function to call when sucessfully
segundo	0:ac1725ba162c	665	* connected. */
segundo	0:ac1725ba162c	666	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
segundo	0:ac1725ba162c	667	if (err == ERR_ABRT) {
segundo	0:ac1725ba162c	668	return ERR_ABRT;
segundo	0:ac1725ba162c	669	}
segundo	0:ac1725ba162c	670	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	671	}
segundo	0:ac1725ba162c	672	/* received ACK? possibly a half-open connection */
segundo	0:ac1725ba162c	673	else if (flags & TCP_ACK) {
segundo	0:ac1725ba162c	674	/* send a RST to bring the other side in a non-synchronized state. */
segundo	0:ac1725ba162c	675	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
segundo	0:ac1725ba162c	676	tcphdr->dest, tcphdr->src);
segundo	0:ac1725ba162c	677	}
segundo	0:ac1725ba162c	678	break;
segundo	0:ac1725ba162c	679	case SYN_RCVD:
segundo	0:ac1725ba162c	680	if (flags & TCP_ACK) {
segundo	0:ac1725ba162c	681	/* expected ACK number? */
segundo	0:ac1725ba162c	682	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
segundo	0:ac1725ba162c	683	u16_t old_cwnd;
segundo	0:ac1725ba162c	684	pcb->state = ESTABLISHED;
segundo	0:ac1725ba162c	685	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
segundo	0:ac1725ba162c	686	#if LWIP_CALLBACK_API
segundo	0:ac1725ba162c	687	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
segundo	0:ac1725ba162c	688	#endif
segundo	0:ac1725ba162c	689	/* Call the accept function. */
segundo	0:ac1725ba162c	690	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
segundo	0:ac1725ba162c	691	if (err != ERR_OK) {
segundo	0:ac1725ba162c	692	/* If the accept function returns with an error, we abort
segundo	0:ac1725ba162c	693	* the connection. */
segundo	0:ac1725ba162c	694	/* Already aborted? */
segundo	0:ac1725ba162c	695	if (err != ERR_ABRT) {
segundo	0:ac1725ba162c	696	tcp_abort(pcb);
segundo	0:ac1725ba162c	697	}
segundo	0:ac1725ba162c	698	return ERR_ABRT;
segundo	0:ac1725ba162c	699	}
segundo	0:ac1725ba162c	700	old_cwnd = pcb->cwnd;
segundo	0:ac1725ba162c	701	/* If there was any data contained within this ACK,
segundo	0:ac1725ba162c	702	* we'd better pass it on to the application as well. */
segundo	0:ac1725ba162c	703	tcp_receive(pcb);
segundo	0:ac1725ba162c	704
segundo	0:ac1725ba162c	705	/* Prevent ACK for SYN to generate a sent event */
segundo	0:ac1725ba162c	706	if (pcb->acked != 0) {
segundo	0:ac1725ba162c	707	pcb->acked--;
segundo	0:ac1725ba162c	708	}
segundo	0:ac1725ba162c	709
segundo	0:ac1725ba162c	710	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
segundo	0:ac1725ba162c	711
segundo	0:ac1725ba162c	712	if (recv_flags & TF_GOT_FIN) {
segundo	0:ac1725ba162c	713	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	714	pcb->state = CLOSE_WAIT;
segundo	0:ac1725ba162c	715	}
segundo	0:ac1725ba162c	716	} else {
segundo	0:ac1725ba162c	717	/* incorrect ACK number, send RST */
segundo	0:ac1725ba162c	718	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
segundo	0:ac1725ba162c	719	tcphdr->dest, tcphdr->src);
segundo	0:ac1725ba162c	720	}
segundo	0:ac1725ba162c	721	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
segundo	0:ac1725ba162c	722	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
segundo	0:ac1725ba162c	723	tcp_rexmit(pcb);
segundo	0:ac1725ba162c	724	}
segundo	0:ac1725ba162c	725	break;
segundo	0:ac1725ba162c	726	case CLOSE_WAIT:
segundo	0:ac1725ba162c	727	/* FALLTHROUGH */
segundo	0:ac1725ba162c	728	case ESTABLISHED:
segundo	0:ac1725ba162c	729	tcp_receive(pcb);
segundo	0:ac1725ba162c	730	if (recv_flags & TF_GOT_FIN) { /* passive close */
segundo	0:ac1725ba162c	731	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	732	pcb->state = CLOSE_WAIT;
segundo	0:ac1725ba162c	733	}
segundo	0:ac1725ba162c	734	break;
segundo	0:ac1725ba162c	735	case FIN_WAIT_1:
segundo	0:ac1725ba162c	736	tcp_receive(pcb);
segundo	0:ac1725ba162c	737	if (recv_flags & TF_GOT_FIN) {
segundo	0:ac1725ba162c	738	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
segundo	0:ac1725ba162c	739	LWIP_DEBUGF(TCP_DEBUG,
segundo	0:ac1725ba162c	740	("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
segundo	0:ac1725ba162c	741	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	742	tcp_pcb_purge(pcb);
segundo	0:ac1725ba162c	743	TCP_RMV(&tcp_active_pcbs, pcb);
segundo	0:ac1725ba162c	744	pcb->state = TIME_WAIT;
segundo	0:ac1725ba162c	745	TCP_REG(&tcp_tw_pcbs, pcb);
segundo	0:ac1725ba162c	746	} else {
segundo	0:ac1725ba162c	747	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	748	pcb->state = CLOSING;
segundo	0:ac1725ba162c	749	}
segundo	0:ac1725ba162c	750	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
segundo	0:ac1725ba162c	751	pcb->state = FIN_WAIT_2;
segundo	0:ac1725ba162c	752	}
segundo	0:ac1725ba162c	753	break;
segundo	0:ac1725ba162c	754	case FIN_WAIT_2:
segundo	0:ac1725ba162c	755	tcp_receive(pcb);
segundo	0:ac1725ba162c	756	if (recv_flags & TF_GOT_FIN) {
segundo	0:ac1725ba162c	757	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
segundo	0:ac1725ba162c	758	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	759	tcp_pcb_purge(pcb);
segundo	0:ac1725ba162c	760	TCP_RMV(&tcp_active_pcbs, pcb);
segundo	0:ac1725ba162c	761	pcb->state = TIME_WAIT;
segundo	0:ac1725ba162c	762	TCP_REG(&tcp_tw_pcbs, pcb);
segundo	0:ac1725ba162c	763	}
segundo	0:ac1725ba162c	764	break;
segundo	0:ac1725ba162c	765	case CLOSING:
segundo	0:ac1725ba162c	766	tcp_receive(pcb);
segundo	0:ac1725ba162c	767	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
segundo	0:ac1725ba162c	768	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
segundo	0:ac1725ba162c	769	tcp_pcb_purge(pcb);
segundo	0:ac1725ba162c	770	TCP_RMV(&tcp_active_pcbs, pcb);
segundo	0:ac1725ba162c	771	pcb->state = TIME_WAIT;
segundo	0:ac1725ba162c	772	TCP_REG(&tcp_tw_pcbs, pcb);
segundo	0:ac1725ba162c	773	}
segundo	0:ac1725ba162c	774	break;
segundo	0:ac1725ba162c	775	case LAST_ACK:
segundo	0:ac1725ba162c	776	tcp_receive(pcb);
segundo	0:ac1725ba162c	777	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
segundo	0:ac1725ba162c	778	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
segundo	0:ac1725ba162c	779	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
segundo	0:ac1725ba162c	780	recv_flags \|= TF_CLOSED;
segundo	0:ac1725ba162c	781	}
segundo	0:ac1725ba162c	782	break;
segundo	0:ac1725ba162c	783	default:
segundo	0:ac1725ba162c	784	break;
segundo	0:ac1725ba162c	785	}
segundo	0:ac1725ba162c	786	return ERR_OK;
segundo	0:ac1725ba162c	787	}
segundo	0:ac1725ba162c	788
segundo	0:ac1725ba162c	789	#if TCP_QUEUE_OOSEQ
segundo	0:ac1725ba162c	790	/**
segundo	0:ac1725ba162c	791	* Insert segment into the list (segments covered with new one will be deleted)
segundo	0:ac1725ba162c	792	*
segundo	0:ac1725ba162c	793	* Called from tcp_receive()
segundo	0:ac1725ba162c	794	*/
segundo	0:ac1725ba162c	795	static void
segundo	0:ac1725ba162c	796	tcp_oos_insert_segment(struct tcp_seg cseg, struct tcp_seg next)
segundo	0:ac1725ba162c	797	{
segundo	0:ac1725ba162c	798	struct tcp_seg *old_seg;
segundo	0:ac1725ba162c	799
segundo	0:ac1725ba162c	800	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	801	/* received segment overlaps all following segments */
segundo	0:ac1725ba162c	802	tcp_segs_free(next);
segundo	0:ac1725ba162c	803	next = NULL;
segundo	0:ac1725ba162c	804	}
segundo	0:ac1725ba162c	805	else {
segundo	0:ac1725ba162c	806	/* delete some following segments
segundo	0:ac1725ba162c	807	oos queue may have segments with FIN flag */
segundo	0:ac1725ba162c	808	while (next &&
segundo	0:ac1725ba162c	809	TCP_SEQ_GEQ((seqno + cseg->len),
segundo	0:ac1725ba162c	810	(next->tcphdr->seqno + next->len))) {
segundo	0:ac1725ba162c	811	/* cseg with FIN already processed */
segundo	0:ac1725ba162c	812	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	813	TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
segundo	0:ac1725ba162c	814	}
segundo	0:ac1725ba162c	815	old_seg = next;
segundo	0:ac1725ba162c	816	next = next->next;
segundo	0:ac1725ba162c	817	tcp_seg_free(old_seg);
segundo	0:ac1725ba162c	818	}
segundo	0:ac1725ba162c	819	if (next &&
segundo	0:ac1725ba162c	820	TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
segundo	0:ac1725ba162c	821	/* We need to trim the incoming segment. */
segundo	0:ac1725ba162c	822	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
segundo	0:ac1725ba162c	823	pbuf_realloc(cseg->p, cseg->len);
segundo	0:ac1725ba162c	824	}
segundo	0:ac1725ba162c	825	}
segundo	0:ac1725ba162c	826	cseg->next = next;
segundo	0:ac1725ba162c	827	}
segundo	0:ac1725ba162c	828	#endif /* TCP_QUEUE_OOSEQ */
segundo	0:ac1725ba162c	829
segundo	0:ac1725ba162c	830	/**
segundo	0:ac1725ba162c	831	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
segundo	0:ac1725ba162c	832	* data, and if so frees the memory of the buffered data. Next, is places the
segundo	0:ac1725ba162c	833	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
segundo	0:ac1725ba162c	834	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
segundo	0:ac1725ba162c	835	* i it has been removed from the buffer.
segundo	0:ac1725ba162c	836	*
segundo	0:ac1725ba162c	837	* If the incoming segment constitutes an ACK for a segment that was used for RTT
segundo	0:ac1725ba162c	838	* estimation, the RTT is estimated here as well.
segundo	0:ac1725ba162c	839	*
segundo	0:ac1725ba162c	840	* Called from tcp_process().
segundo	0:ac1725ba162c	841	*/
segundo	0:ac1725ba162c	842	static void
segundo	0:ac1725ba162c	843	tcp_receive(struct tcp_pcb *pcb)
segundo	0:ac1725ba162c	844	{
segundo	0:ac1725ba162c	845	struct tcp_seg *next;
segundo	0:ac1725ba162c	846	#if TCP_QUEUE_OOSEQ
segundo	0:ac1725ba162c	847	struct tcp_seg prev, cseg;
segundo	0:ac1725ba162c	848	#endif /* TCP_QUEUE_OOSEQ */
segundo	0:ac1725ba162c	849	struct pbuf *p;
segundo	0:ac1725ba162c	850	s32_t off;
segundo	0:ac1725ba162c	851	s16_t m;
segundo	0:ac1725ba162c	852	u32_t right_wnd_edge;
segundo	0:ac1725ba162c	853	u16_t new_tot_len;
segundo	0:ac1725ba162c	854	int found_dupack = 0;
segundo	0:ac1725ba162c	855
segundo	0:ac1725ba162c	856	if (flags & TCP_ACK) {
segundo	0:ac1725ba162c	857	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
segundo	0:ac1725ba162c	858
segundo	0:ac1725ba162c	859	/* Update window. */
segundo	0:ac1725ba162c	860	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
segundo	0:ac1725ba162c	861	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
segundo	0:ac1725ba162c	862	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
segundo	0:ac1725ba162c	863	pcb->snd_wnd = tcphdr->wnd;
segundo	0:ac1725ba162c	864	pcb->snd_wl1 = seqno;
segundo	0:ac1725ba162c	865	pcb->snd_wl2 = ackno;
segundo	0:ac1725ba162c	866	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
segundo	0:ac1725ba162c	867	pcb->persist_backoff = 0;
segundo	0:ac1725ba162c	868	}
segundo	0:ac1725ba162c	869	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
segundo	0:ac1725ba162c	870	#if TCP_WND_DEBUG
segundo	0:ac1725ba162c	871	} else {
segundo	0:ac1725ba162c	872	if (pcb->snd_wnd != tcphdr->wnd) {
segundo	0:ac1725ba162c	873	LWIP_DEBUGF(TCP_WND_DEBUG,
segundo	0:ac1725ba162c	874	("tcp_receive: no window update lastack %"U32_F" ackno %"
segundo	0:ac1725ba162c	875	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
segundo	0:ac1725ba162c	876	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
segundo	0:ac1725ba162c	877	}
segundo	0:ac1725ba162c	878	#endif /* TCP_WND_DEBUG */
segundo	0:ac1725ba162c	879	}
segundo	0:ac1725ba162c	880
segundo	0:ac1725ba162c	881	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
segundo	0:ac1725ba162c	882	* duplicate ack if:
segundo	0:ac1725ba162c	883	* 1) It doesn't ACK new data
segundo	0:ac1725ba162c	884	* 2) length of received packet is zero (i.e. no payload)
segundo	0:ac1725ba162c	885	* 3) the advertised window hasn't changed
segundo	0:ac1725ba162c	886	* 4) There is outstanding unacknowledged data (retransmission timer running)
segundo	0:ac1725ba162c	887	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
segundo	0:ac1725ba162c	888	*
segundo	0:ac1725ba162c	889	* If it passes all five, should process as a dupack:
segundo	0:ac1725ba162c	890	* a) dupacks < 3: do nothing
segundo	0:ac1725ba162c	891	* b) dupacks == 3: fast retransmit
segundo	0:ac1725ba162c	892	* c) dupacks > 3: increase cwnd
segundo	0:ac1725ba162c	893	*
segundo	0:ac1725ba162c	894	* If it only passes 1-3, should reset dupack counter (and add to
segundo	0:ac1725ba162c	895	* stats, which we don't do in lwIP)
segundo	0:ac1725ba162c	896	*
segundo	0:ac1725ba162c	897	* If it only passes 1, should reset dupack counter
segundo	0:ac1725ba162c	898	*
segundo	0:ac1725ba162c	899	*/
segundo	0:ac1725ba162c	900
segundo	0:ac1725ba162c	901	/* Clause 1 */
segundo	0:ac1725ba162c	902	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
segundo	0:ac1725ba162c	903	pcb->acked = 0;
segundo	0:ac1725ba162c	904	/* Clause 2 */
segundo	0:ac1725ba162c	905	if (tcplen == 0) {
segundo	0:ac1725ba162c	906	/* Clause 3 */
segundo	0:ac1725ba162c	907	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
segundo	0:ac1725ba162c	908	/* Clause 4 */
segundo	0:ac1725ba162c	909	if (pcb->rtime >= 0) {
segundo	0:ac1725ba162c	910	/* Clause 5 */
segundo	0:ac1725ba162c	911	if (pcb->lastack == ackno) {
segundo	0:ac1725ba162c	912	found_dupack = 1;
segundo	0:ac1725ba162c	913	if (pcb->dupacks + 1 > pcb->dupacks)
segundo	0:ac1725ba162c	914	++pcb->dupacks;
segundo	0:ac1725ba162c	915	if (pcb->dupacks > 3) {
segundo	0:ac1725ba162c	916	/* Inflate the congestion window, but not if it means that
segundo	0:ac1725ba162c	917	the value overflows. */
segundo	0:ac1725ba162c	918	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
segundo	0:ac1725ba162c	919	pcb->cwnd += pcb->mss;
segundo	0:ac1725ba162c	920	}
segundo	0:ac1725ba162c	921	} else if (pcb->dupacks == 3) {
segundo	0:ac1725ba162c	922	/* Do fast retransmit */
segundo	0:ac1725ba162c	923	tcp_rexmit_fast(pcb);
segundo	0:ac1725ba162c	924	}
segundo	0:ac1725ba162c	925	}
segundo	0:ac1725ba162c	926	}
segundo	0:ac1725ba162c	927	}
segundo	0:ac1725ba162c	928	}
segundo	0:ac1725ba162c	929	/* If Clause (1) or more is true, but not a duplicate ack, reset
segundo	0:ac1725ba162c	930	* count of consecutive duplicate acks */
segundo	0:ac1725ba162c	931	if (!found_dupack) {
segundo	0:ac1725ba162c	932	pcb->dupacks = 0;
segundo	0:ac1725ba162c	933	}
segundo	0:ac1725ba162c	934	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
segundo	0:ac1725ba162c	935	/* We come here when the ACK acknowledges new data. */
segundo	0:ac1725ba162c	936
segundo	0:ac1725ba162c	937	/* Reset the "IN Fast Retransmit" flag, since we are no longer
segundo	0:ac1725ba162c	938	in fast retransmit. Also reset the congestion window to the
segundo	0:ac1725ba162c	939	slow start threshold. */
segundo	0:ac1725ba162c	940	if (pcb->flags & TF_INFR) {
segundo	0:ac1725ba162c	941	pcb->flags &= ~TF_INFR;
segundo	0:ac1725ba162c	942	pcb->cwnd = pcb->ssthresh;
segundo	0:ac1725ba162c	943	}
segundo	0:ac1725ba162c	944
segundo	0:ac1725ba162c	945	/* Reset the number of retransmissions. */
segundo	0:ac1725ba162c	946	pcb->nrtx = 0;
segundo	0:ac1725ba162c	947
segundo	0:ac1725ba162c	948	/* Reset the retransmission time-out. */
segundo	0:ac1725ba162c	949	pcb->rto = (pcb->sa >> 3) + pcb->sv;
segundo	0:ac1725ba162c	950
segundo	0:ac1725ba162c	951	/* Update the send buffer space. Diff between the two can never exceed 64K? */
segundo	0:ac1725ba162c	952	pcb->acked = (u16_t)(ackno - pcb->lastack);
segundo	0:ac1725ba162c	953
segundo	0:ac1725ba162c	954	pcb->snd_buf += pcb->acked;
segundo	0:ac1725ba162c	955
segundo	0:ac1725ba162c	956	/* Reset the fast retransmit variables. */
segundo	0:ac1725ba162c	957	pcb->dupacks = 0;
segundo	0:ac1725ba162c	958	pcb->lastack = ackno;
segundo	0:ac1725ba162c	959
segundo	0:ac1725ba162c	960	/* Update the congestion control variables (cwnd and
segundo	0:ac1725ba162c	961	ssthresh). */
segundo	0:ac1725ba162c	962	if (pcb->state >= ESTABLISHED) {
segundo	0:ac1725ba162c	963	if (pcb->cwnd < pcb->ssthresh) {
segundo	0:ac1725ba162c	964	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
segundo	0:ac1725ba162c	965	pcb->cwnd += pcb->mss;
segundo	0:ac1725ba162c	966	}
segundo	0:ac1725ba162c	967	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
segundo	0:ac1725ba162c	968	} else {
segundo	0:ac1725ba162c	969	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
segundo	0:ac1725ba162c	970	if (new_cwnd > pcb->cwnd) {
segundo	0:ac1725ba162c	971	pcb->cwnd = new_cwnd;
segundo	0:ac1725ba162c	972	}
segundo	0:ac1725ba162c	973	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
segundo	0:ac1725ba162c	974	}
segundo	0:ac1725ba162c	975	}
segundo	0:ac1725ba162c	976	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
segundo	0:ac1725ba162c	977	ackno,
segundo	0:ac1725ba162c	978	pcb->unacked != NULL?
segundo	0:ac1725ba162c	979	ntohl(pcb->unacked->tcphdr->seqno): 0,
segundo	0:ac1725ba162c	980	pcb->unacked != NULL?
segundo	0:ac1725ba162c	981	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
segundo	0:ac1725ba162c	982
segundo	0:ac1725ba162c	983	/* Remove segment from the unacknowledged list if the incoming
segundo	0:ac1725ba162c	984	ACK acknowlegdes them. */
segundo	0:ac1725ba162c	985	while (pcb->unacked != NULL &&
segundo	0:ac1725ba162c	986	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
segundo	0:ac1725ba162c	987	TCP_TCPLEN(pcb->unacked), ackno)) {
segundo	0:ac1725ba162c	988	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
segundo	0:ac1725ba162c	989	ntohl(pcb->unacked->tcphdr->seqno),
segundo	0:ac1725ba162c	990	ntohl(pcb->unacked->tcphdr->seqno) +
segundo	0:ac1725ba162c	991	TCP_TCPLEN(pcb->unacked)));
segundo	0:ac1725ba162c	992
segundo	0:ac1725ba162c	993	next = pcb->unacked;
segundo	0:ac1725ba162c	994	pcb->unacked = pcb->unacked->next;
segundo	0:ac1725ba162c	995
segundo	0:ac1725ba162c	996	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
segundo	0:ac1725ba162c	997	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
segundo	0:ac1725ba162c	998	/* Prevent ACK for FIN to generate a sent event */
segundo	0:ac1725ba162c	999	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
segundo	0:ac1725ba162c	1000	pcb->acked--;
segundo	0:ac1725ba162c	1001	}
segundo	0:ac1725ba162c	1002
segundo	0:ac1725ba162c	1003	pcb->snd_queuelen -= pbuf_clen(next->p);
segundo	0:ac1725ba162c	1004	tcp_seg_free(next);
segundo	0:ac1725ba162c	1005
segundo	0:ac1725ba162c	1006	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
segundo	0:ac1725ba162c	1007	if (pcb->snd_queuelen != 0) {
segundo	0:ac1725ba162c	1008	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
segundo	0:ac1725ba162c	1009	pcb->unsent != NULL);
segundo	0:ac1725ba162c	1010	}
segundo	0:ac1725ba162c	1011	}
segundo	0:ac1725ba162c	1012
segundo	0:ac1725ba162c	1013	/* If there's nothing left to acknowledge, stop the retransmit
segundo	0:ac1725ba162c	1014	timer, otherwise reset it to start again */
segundo	0:ac1725ba162c	1015	if(pcb->unacked == NULL)
segundo	0:ac1725ba162c	1016	pcb->rtime = -1;
segundo	0:ac1725ba162c	1017	else
segundo	0:ac1725ba162c	1018	pcb->rtime = 0;
segundo	0:ac1725ba162c	1019
segundo	0:ac1725ba162c	1020	pcb->polltmr = 0;
segundo	0:ac1725ba162c	1021	} else {
segundo	0:ac1725ba162c	1022	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
segundo	0:ac1725ba162c	1023	pcb->acked = 0;
segundo	0:ac1725ba162c	1024	}
segundo	0:ac1725ba162c	1025
segundo	0:ac1725ba162c	1026	/* We go through the ->unsent list to see if any of the segments
segundo	0:ac1725ba162c	1027	on the list are acknowledged by the ACK. This may seem
segundo	0:ac1725ba162c	1028	strange since an "unsent" segment shouldn't be acked. The
segundo	0:ac1725ba162c	1029	rationale is that lwIP puts all outstanding segments on the
segundo	0:ac1725ba162c	1030	->unsent list after a retransmission, so these segments may
segundo	0:ac1725ba162c	1031	in fact have been sent once. */
segundo	0:ac1725ba162c	1032	while (pcb->unsent != NULL &&
segundo	0:ac1725ba162c	1033	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
segundo	0:ac1725ba162c	1034	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
segundo	0:ac1725ba162c	1035	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
segundo	0:ac1725ba162c	1036	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
segundo	0:ac1725ba162c	1037	TCP_TCPLEN(pcb->unsent)));
segundo	0:ac1725ba162c	1038
segundo	0:ac1725ba162c	1039	next = pcb->unsent;
segundo	0:ac1725ba162c	1040	pcb->unsent = pcb->unsent->next;
segundo	0:ac1725ba162c	1041	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
segundo	0:ac1725ba162c	1042	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
segundo	0:ac1725ba162c	1043	/* Prevent ACK for FIN to generate a sent event */
segundo	0:ac1725ba162c	1044	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
segundo	0:ac1725ba162c	1045	pcb->acked--;
segundo	0:ac1725ba162c	1046	}
segundo	0:ac1725ba162c	1047	pcb->snd_queuelen -= pbuf_clen(next->p);
segundo	0:ac1725ba162c	1048	tcp_seg_free(next);
segundo	0:ac1725ba162c	1049	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
segundo	0:ac1725ba162c	1050	if (pcb->snd_queuelen != 0) {
segundo	0:ac1725ba162c	1051	LWIP_ASSERT("tcp_receive: valid queue length",
segundo	0:ac1725ba162c	1052	pcb->unacked != NULL \|\| pcb->unsent != NULL);
segundo	0:ac1725ba162c	1053	}
segundo	0:ac1725ba162c	1054	}
segundo	0:ac1725ba162c	1055	/* End of ACK for new data processing. */
segundo	0:ac1725ba162c	1056
segundo	0:ac1725ba162c	1057	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
segundo	0:ac1725ba162c	1058	pcb->rttest, pcb->rtseq, ackno));
segundo	0:ac1725ba162c	1059
segundo	0:ac1725ba162c	1060	/* RTT estimation calculations. This is done by checking if the
segundo	0:ac1725ba162c	1061	incoming segment acknowledges the segment we use to take a
segundo	0:ac1725ba162c	1062	round-trip time measurement. */
segundo	0:ac1725ba162c	1063	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
segundo	0:ac1725ba162c	1064	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
segundo	0:ac1725ba162c	1065	and a round-trip shouldn't be that long... */
segundo	0:ac1725ba162c	1066	m = (s16_t)(tcp_ticks - pcb->rttest);
segundo	0:ac1725ba162c	1067
segundo	0:ac1725ba162c	1068	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
segundo	0:ac1725ba162c	1069	m, m * TCP_SLOW_INTERVAL));
segundo	0:ac1725ba162c	1070
segundo	0:ac1725ba162c	1071	/* This is taken directly from VJs original code in his paper */
segundo	0:ac1725ba162c	1072	m = m - (pcb->sa >> 3);
segundo	0:ac1725ba162c	1073	pcb->sa += m;
segundo	0:ac1725ba162c	1074	if (m < 0) {
segundo	0:ac1725ba162c	1075	m = -m;
segundo	0:ac1725ba162c	1076	}
segundo	0:ac1725ba162c	1077	m = m - (pcb->sv >> 2);
segundo	0:ac1725ba162c	1078	pcb->sv += m;
segundo	0:ac1725ba162c	1079	pcb->rto = (pcb->sa >> 3) + pcb->sv;
segundo	0:ac1725ba162c	1080
segundo	0:ac1725ba162c	1081	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
segundo	0:ac1725ba162c	1082	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
segundo	0:ac1725ba162c	1083
segundo	0:ac1725ba162c	1084	pcb->rttest = 0;
segundo	0:ac1725ba162c	1085	}
segundo	0:ac1725ba162c	1086	}
segundo	0:ac1725ba162c	1087
segundo	0:ac1725ba162c	1088	/* If the incoming segment contains data, we must process it
segundo	0:ac1725ba162c	1089	further. */
segundo	0:ac1725ba162c	1090	if (tcplen > 0) {
segundo	0:ac1725ba162c	1091	/* This code basically does three things:
segundo	0:ac1725ba162c	1092
segundo	0:ac1725ba162c	1093	+) If the incoming segment contains data that is the next
segundo	0:ac1725ba162c	1094	in-sequence data, this data is passed to the application. This
segundo	0:ac1725ba162c	1095	might involve trimming the first edge of the data. The rcv_nxt
segundo	0:ac1725ba162c	1096	variable and the advertised window are adjusted.
segundo	0:ac1725ba162c	1097
segundo	0:ac1725ba162c	1098	+) If the incoming segment has data that is above the next
segundo	0:ac1725ba162c	1099	sequence number expected (->rcv_nxt), the segment is placed on
segundo	0:ac1725ba162c	1100	the ->ooseq queue. This is done by finding the appropriate
segundo	0:ac1725ba162c	1101	place in the ->ooseq queue (which is ordered by sequence
segundo	0:ac1725ba162c	1102	number) and trim the segment in both ends if needed. An
segundo	0:ac1725ba162c	1103	immediate ACK is sent to indicate that we received an
segundo	0:ac1725ba162c	1104	out-of-sequence segment.
segundo	0:ac1725ba162c	1105
segundo	0:ac1725ba162c	1106	+) Finally, we check if the first segment on the ->ooseq queue
segundo	0:ac1725ba162c	1107	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
segundo	0:ac1725ba162c	1108	rcv_nxt > ooseq->seqno, we must trim the first edge of the
segundo	0:ac1725ba162c	1109	segment on ->ooseq before we adjust rcv_nxt. The data in the
segundo	0:ac1725ba162c	1110	segments that are now on sequence are chained onto the
segundo	0:ac1725ba162c	1111	incoming segment so that we only need to call the application
segundo	0:ac1725ba162c	1112	once.
segundo	0:ac1725ba162c	1113	*/
segundo	0:ac1725ba162c	1114
segundo	0:ac1725ba162c	1115	/* First, we check if we must trim the first edge. We have to do
segundo	0:ac1725ba162c	1116	this if the sequence number of the incoming segment is less
segundo	0:ac1725ba162c	1117	than rcv_nxt, and the sequence number plus the length of the
segundo	0:ac1725ba162c	1118	segment is larger than rcv_nxt. */
segundo	0:ac1725ba162c	1119	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
segundo	0:ac1725ba162c	1120	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
segundo	0:ac1725ba162c	1121	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
segundo	0:ac1725ba162c	1122	/* Trimming the first edge is done by pushing the payload
segundo	0:ac1725ba162c	1123	pointer in the pbuf downwards. This is somewhat tricky since
segundo	0:ac1725ba162c	1124	we do not want to discard the full contents of the pbuf up to
segundo	0:ac1725ba162c	1125	the new starting point of the data since we have to keep the
segundo	0:ac1725ba162c	1126	TCP header which is present in the first pbuf in the chain.
segundo	0:ac1725ba162c	1127
segundo	0:ac1725ba162c	1128	What is done is really quite a nasty hack: the first pbuf in
segundo	0:ac1725ba162c	1129	the pbuf chain is pointed to by inseg.p. Since we need to be
segundo	0:ac1725ba162c	1130	able to deallocate the whole pbuf, we cannot change this
segundo	0:ac1725ba162c	1131	inseg.p pointer to point to any of the later pbufs in the
segundo	0:ac1725ba162c	1132	chain. Instead, we point the ->payload pointer in the first
segundo	0:ac1725ba162c	1133	pbuf to data in one of the later pbufs. We also set the
segundo	0:ac1725ba162c	1134	inseg.data pointer to point to the right place. This way, the
segundo	0:ac1725ba162c	1135	->p pointer will still point to the first pbuf, but the
segundo	0:ac1725ba162c	1136	->p->payload pointer will point to data in another pbuf.
segundo	0:ac1725ba162c	1137
segundo	0:ac1725ba162c	1138	After we are done with adjusting the pbuf pointers we must
segundo	0:ac1725ba162c	1139	adjust the ->data pointer in the seg and the segment
segundo	0:ac1725ba162c	1140	length.*/
segundo	0:ac1725ba162c	1141
segundo	0:ac1725ba162c	1142	off = pcb->rcv_nxt - seqno;
segundo	0:ac1725ba162c	1143	p = inseg.p;
segundo	0:ac1725ba162c	1144	LWIP_ASSERT("inseg.p != NULL", inseg.p);
segundo	0:ac1725ba162c	1145	LWIP_ASSERT("insane offset!", (off < 0x7fff));
segundo	0:ac1725ba162c	1146	if (inseg.p->len < off) {
segundo	0:ac1725ba162c	1147	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
segundo	0:ac1725ba162c	1148	new_tot_len = (u16_t)(inseg.p->tot_len - off);
segundo	0:ac1725ba162c	1149	while (p->len < off) {
segundo	0:ac1725ba162c	1150	off -= p->len;
segundo	0:ac1725ba162c	1151	/* KJM following line changed (with addition of new_tot_len var)
segundo	0:ac1725ba162c	1152	to fix bug #9076
segundo	0:ac1725ba162c	1153	inseg.p->tot_len -= p->len; */
segundo	0:ac1725ba162c	1154	p->tot_len = new_tot_len;
segundo	0:ac1725ba162c	1155	p->len = 0;
segundo	0:ac1725ba162c	1156	p = p->next;
segundo	0:ac1725ba162c	1157	}
segundo	0:ac1725ba162c	1158	if(pbuf_header(p, (s16_t)-off)) {
segundo	0:ac1725ba162c	1159	/* Do we need to cope with this failing? Assert for now */
segundo	0:ac1725ba162c	1160	LWIP_ASSERT("pbuf_header failed", 0);
segundo	0:ac1725ba162c	1161	}
segundo	0:ac1725ba162c	1162	} else {
segundo	0:ac1725ba162c	1163	if(pbuf_header(inseg.p, (s16_t)-off)) {
segundo	0:ac1725ba162c	1164	/* Do we need to cope with this failing? Assert for now */
segundo	0:ac1725ba162c	1165	LWIP_ASSERT("pbuf_header failed", 0);
segundo	0:ac1725ba162c	1166	}
segundo	0:ac1725ba162c	1167	}
segundo	0:ac1725ba162c	1168	/* KJM following line changed to use p->payload rather than inseg->p->payload
segundo	0:ac1725ba162c	1169	to fix bug #9076 */
segundo	0:ac1725ba162c	1170	inseg.dataptr = p->payload;
segundo	0:ac1725ba162c	1171	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
segundo	0:ac1725ba162c	1172	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
segundo	0:ac1725ba162c	1173	}
segundo	0:ac1725ba162c	1174	else {
segundo	0:ac1725ba162c	1175	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
segundo	0:ac1725ba162c	1176	/* the whole segment is < rcv_nxt */
segundo	0:ac1725ba162c	1177	/* must be a duplicate of a packet that has already been correctly handled */
segundo	0:ac1725ba162c	1178
segundo	0:ac1725ba162c	1179	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
segundo	0:ac1725ba162c	1180	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	1181	}
segundo	0:ac1725ba162c	1182	}
segundo	0:ac1725ba162c	1183
segundo	0:ac1725ba162c	1184	/* The sequence number must be within the window (above rcv_nxt
segundo	0:ac1725ba162c	1185	and below rcv_nxt + rcv_wnd) in order to be further
segundo	0:ac1725ba162c	1186	processed. */
segundo	0:ac1725ba162c	1187	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
segundo	0:ac1725ba162c	1188	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
segundo	0:ac1725ba162c	1189	if (pcb->rcv_nxt == seqno) {
segundo	0:ac1725ba162c	1190	/* The incoming segment is the next in sequence. We check if
segundo	0:ac1725ba162c	1191	we have to trim the end of the segment and update rcv_nxt
segundo	0:ac1725ba162c	1192	and pass the data to the application. */
segundo	0:ac1725ba162c	1193	tcplen = TCP_TCPLEN(&inseg);
segundo	0:ac1725ba162c	1194
segundo	0:ac1725ba162c	1195	if (tcplen > pcb->rcv_wnd) {
segundo	0:ac1725ba162c	1196	LWIP_DEBUGF(TCP_INPUT_DEBUG,
segundo	0:ac1725ba162c	1197	("tcp_receive: other end overran receive window"
segundo	0:ac1725ba162c	1198	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
segundo	0:ac1725ba162c	1199	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
segundo	0:ac1725ba162c	1200	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1201	/* Must remove the FIN from the header as we're trimming
segundo	0:ac1725ba162c	1202	* that byte of sequence-space from the packet */
segundo	0:ac1725ba162c	1203	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
segundo	0:ac1725ba162c	1204	}
segundo	0:ac1725ba162c	1205	/* Adjust length of segment to fit in the window. */
segundo	0:ac1725ba162c	1206	inseg.len = pcb->rcv_wnd;
segundo	0:ac1725ba162c	1207	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
segundo	0:ac1725ba162c	1208	inseg.len -= 1;
segundo	0:ac1725ba162c	1209	}
segundo	0:ac1725ba162c	1210	pbuf_realloc(inseg.p, inseg.len);
segundo	0:ac1725ba162c	1211	tcplen = TCP_TCPLEN(&inseg);
segundo	0:ac1725ba162c	1212	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
segundo	0:ac1725ba162c	1213	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
segundo	0:ac1725ba162c	1214	}
segundo	0:ac1725ba162c	1215	#if TCP_QUEUE_OOSEQ
segundo	0:ac1725ba162c	1216	/* Received in-sequence data, adjust ooseq data if:
segundo	0:ac1725ba162c	1217	- FIN has been received or
segundo	0:ac1725ba162c	1218	- inseq overlaps with ooseq */
segundo	0:ac1725ba162c	1219	if (pcb->ooseq != NULL) {
segundo	0:ac1725ba162c	1220	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1221	LWIP_DEBUGF(TCP_INPUT_DEBUG,
segundo	0:ac1725ba162c	1222	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
segundo	0:ac1725ba162c	1223	/* Received in-order FIN means anything that was received
segundo	0:ac1725ba162c	1224	* out of order must now have been received in-order, so
segundo	0:ac1725ba162c	1225	* bin the ooseq queue */
segundo	0:ac1725ba162c	1226	while (pcb->ooseq != NULL) {
segundo	0:ac1725ba162c	1227	struct tcp_seg *old_ooseq = pcb->ooseq;
segundo	0:ac1725ba162c	1228	pcb->ooseq = pcb->ooseq->next;
segundo	0:ac1725ba162c	1229	tcp_seg_free(old_ooseq);
segundo	0:ac1725ba162c	1230	}
segundo	0:ac1725ba162c	1231	}
segundo	0:ac1725ba162c	1232	else {
segundo	0:ac1725ba162c	1233	next = pcb->ooseq;
segundo	0:ac1725ba162c	1234	/* Remove all segments on ooseq that are covered by inseg already.
segundo	0:ac1725ba162c	1235	* FIN is copied from ooseq to inseg if present. */
segundo	0:ac1725ba162c	1236	while (next &&
segundo	0:ac1725ba162c	1237	TCP_SEQ_GEQ(seqno + tcplen,
segundo	0:ac1725ba162c	1238	next->tcphdr->seqno + next->len)) {
segundo	0:ac1725ba162c	1239	/* inseg cannot have FIN here (already processed above) */
segundo	0:ac1725ba162c	1240	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
segundo	0:ac1725ba162c	1241	(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
segundo	0:ac1725ba162c	1242	TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
segundo	0:ac1725ba162c	1243	tcplen = TCP_TCPLEN(&inseg);
segundo	0:ac1725ba162c	1244	}
segundo	0:ac1725ba162c	1245	prev = next;
segundo	0:ac1725ba162c	1246	next = next->next;
segundo	0:ac1725ba162c	1247	tcp_seg_free(prev);
segundo	0:ac1725ba162c	1248	}
segundo	0:ac1725ba162c	1249	/* Now trim right side of inseg if it overlaps with the first
segundo	0:ac1725ba162c	1250	* segment on ooseq */
segundo	0:ac1725ba162c	1251	if (next &&
segundo	0:ac1725ba162c	1252	TCP_SEQ_GT(seqno + tcplen,
segundo	0:ac1725ba162c	1253	next->tcphdr->seqno)) {
segundo	0:ac1725ba162c	1254	/* inseg cannot have FIN here (already processed above) */
segundo	0:ac1725ba162c	1255	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
segundo	0:ac1725ba162c	1256	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
segundo	0:ac1725ba162c	1257	inseg.len -= 1;
segundo	0:ac1725ba162c	1258	}
segundo	0:ac1725ba162c	1259	pbuf_realloc(inseg.p, inseg.len);
segundo	0:ac1725ba162c	1260	tcplen = TCP_TCPLEN(&inseg);
segundo	0:ac1725ba162c	1261	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
segundo	0:ac1725ba162c	1262	(seqno + tcplen) == next->tcphdr->seqno);
segundo	0:ac1725ba162c	1263	}
segundo	0:ac1725ba162c	1264	pcb->ooseq = next;
segundo	0:ac1725ba162c	1265	}
segundo	0:ac1725ba162c	1266	}
segundo	0:ac1725ba162c	1267	#endif /* TCP_QUEUE_OOSEQ */
segundo	0:ac1725ba162c	1268
segundo	0:ac1725ba162c	1269	pcb->rcv_nxt = seqno + tcplen;
segundo	0:ac1725ba162c	1270
segundo	0:ac1725ba162c	1271	/* Update the receiver's (our) window. */
segundo	0:ac1725ba162c	1272	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
segundo	0:ac1725ba162c	1273	pcb->rcv_wnd -= tcplen;
segundo	0:ac1725ba162c	1274
segundo	0:ac1725ba162c	1275	tcp_update_rcv_ann_wnd(pcb);
segundo	0:ac1725ba162c	1276
segundo	0:ac1725ba162c	1277	/* If there is data in the segment, we make preparations to
segundo	0:ac1725ba162c	1278	pass this up to the application. The ->recv_data variable
segundo	0:ac1725ba162c	1279	is used for holding the pbuf that goes to the
segundo	0:ac1725ba162c	1280	application. The code for reassembling out-of-sequence data
segundo	0:ac1725ba162c	1281	chains its data on this pbuf as well.
segundo	0:ac1725ba162c	1282
segundo	0:ac1725ba162c	1283	If the segment was a FIN, we set the TF_GOT_FIN flag that will
segundo	0:ac1725ba162c	1284	be used to indicate to the application that the remote side has
segundo	0:ac1725ba162c	1285	closed its end of the connection. */
segundo	0:ac1725ba162c	1286	if (inseg.p->tot_len > 0) {
segundo	0:ac1725ba162c	1287	recv_data = inseg.p;
segundo	0:ac1725ba162c	1288	/* Since this pbuf now is the responsibility of the
segundo	0:ac1725ba162c	1289	application, we delete our reference to it so that we won't
segundo	0:ac1725ba162c	1290	(mistakingly) deallocate it. */
segundo	0:ac1725ba162c	1291	inseg.p = NULL;
segundo	0:ac1725ba162c	1292	}
segundo	0:ac1725ba162c	1293	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1294	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
segundo	0:ac1725ba162c	1295	recv_flags \|= TF_GOT_FIN;
segundo	0:ac1725ba162c	1296	}
segundo	0:ac1725ba162c	1297
segundo	0:ac1725ba162c	1298	#if TCP_QUEUE_OOSEQ
segundo	0:ac1725ba162c	1299	/* We now check if we have segments on the ->ooseq queue that
segundo	0:ac1725ba162c	1300	are now in sequence. */
segundo	0:ac1725ba162c	1301	while (pcb->ooseq != NULL &&
segundo	0:ac1725ba162c	1302	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
segundo	0:ac1725ba162c	1303
segundo	0:ac1725ba162c	1304	cseg = pcb->ooseq;
segundo	0:ac1725ba162c	1305	seqno = pcb->ooseq->tcphdr->seqno;
segundo	0:ac1725ba162c	1306
segundo	0:ac1725ba162c	1307	pcb->rcv_nxt += TCP_TCPLEN(cseg);
segundo	0:ac1725ba162c	1308	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
segundo	0:ac1725ba162c	1309	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
segundo	0:ac1725ba162c	1310	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
segundo	0:ac1725ba162c	1311
segundo	0:ac1725ba162c	1312	tcp_update_rcv_ann_wnd(pcb);
segundo	0:ac1725ba162c	1313
segundo	0:ac1725ba162c	1314	if (cseg->p->tot_len > 0) {
segundo	0:ac1725ba162c	1315	/* Chain this pbuf onto the pbuf that we will pass to
segundo	0:ac1725ba162c	1316	the application. */
segundo	0:ac1725ba162c	1317	if (recv_data) {
segundo	0:ac1725ba162c	1318	pbuf_cat(recv_data, cseg->p);
segundo	0:ac1725ba162c	1319	} else {
segundo	0:ac1725ba162c	1320	recv_data = cseg->p;
segundo	0:ac1725ba162c	1321	}
segundo	0:ac1725ba162c	1322	cseg->p = NULL;
segundo	0:ac1725ba162c	1323	}
segundo	0:ac1725ba162c	1324	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1325	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
segundo	0:ac1725ba162c	1326	recv_flags \|= TF_GOT_FIN;
segundo	0:ac1725ba162c	1327	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
segundo	0:ac1725ba162c	1328	pcb->state = CLOSE_WAIT;
segundo	0:ac1725ba162c	1329	}
segundo	0:ac1725ba162c	1330	}
segundo	0:ac1725ba162c	1331
segundo	0:ac1725ba162c	1332	pcb->ooseq = cseg->next;
segundo	0:ac1725ba162c	1333	tcp_seg_free(cseg);
segundo	0:ac1725ba162c	1334	}
segundo	0:ac1725ba162c	1335	#endif /* TCP_QUEUE_OOSEQ */
segundo	0:ac1725ba162c	1336
segundo	0:ac1725ba162c	1337
segundo	0:ac1725ba162c	1338	/* Acknowledge the segment(s). */
segundo	0:ac1725ba162c	1339	tcp_ack(pcb);
segundo	0:ac1725ba162c	1340
segundo	0:ac1725ba162c	1341	} else {
segundo	0:ac1725ba162c	1342	/* We get here if the incoming segment is out-of-sequence. */
segundo	0:ac1725ba162c	1343	tcp_send_empty_ack(pcb);
segundo	0:ac1725ba162c	1344	#if TCP_QUEUE_OOSEQ
segundo	0:ac1725ba162c	1345	/* We queue the segment on the ->ooseq queue. */
segundo	0:ac1725ba162c	1346	if (pcb->ooseq == NULL) {
segundo	0:ac1725ba162c	1347	pcb->ooseq = tcp_seg_copy(&inseg);
segundo	0:ac1725ba162c	1348	} else {
segundo	0:ac1725ba162c	1349	/* If the queue is not empty, we walk through the queue and
segundo	0:ac1725ba162c	1350	try to find a place where the sequence number of the
segundo	0:ac1725ba162c	1351	incoming segment is between the sequence numbers of the
segundo	0:ac1725ba162c	1352	previous and the next segment on the ->ooseq queue. That is
segundo	0:ac1725ba162c	1353	the place where we put the incoming segment. If needed, we
segundo	0:ac1725ba162c	1354	trim the second edges of the previous and the incoming
segundo	0:ac1725ba162c	1355	segment so that it will fit into the sequence.
segundo	0:ac1725ba162c	1356
segundo	0:ac1725ba162c	1357	If the incoming segment has the same sequence number as a
segundo	0:ac1725ba162c	1358	segment on the ->ooseq queue, we discard the segment that
segundo	0:ac1725ba162c	1359	contains less data. */
segundo	0:ac1725ba162c	1360
segundo	0:ac1725ba162c	1361	prev = NULL;
segundo	0:ac1725ba162c	1362	for(next = pcb->ooseq; next != NULL; next = next->next) {
segundo	0:ac1725ba162c	1363	if (seqno == next->tcphdr->seqno) {
segundo	0:ac1725ba162c	1364	/* The sequence number of the incoming segment is the
segundo	0:ac1725ba162c	1365	same as the sequence number of the segment on
segundo	0:ac1725ba162c	1366	->ooseq. We check the lengths to see which one to
segundo	0:ac1725ba162c	1367	discard. */
segundo	0:ac1725ba162c	1368	if (inseg.len > next->len) {
segundo	0:ac1725ba162c	1369	/* The incoming segment is larger than the old
segundo	0:ac1725ba162c	1370	segment. We replace some segments with the new
segundo	0:ac1725ba162c	1371	one. */
segundo	0:ac1725ba162c	1372	cseg = tcp_seg_copy(&inseg);
segundo	0:ac1725ba162c	1373	if (cseg != NULL) {
segundo	0:ac1725ba162c	1374	if (prev != NULL) {
segundo	0:ac1725ba162c	1375	prev->next = cseg;
segundo	0:ac1725ba162c	1376	} else {
segundo	0:ac1725ba162c	1377	pcb->ooseq = cseg;
segundo	0:ac1725ba162c	1378	}
segundo	0:ac1725ba162c	1379	tcp_oos_insert_segment(cseg, next);
segundo	0:ac1725ba162c	1380	}
segundo	0:ac1725ba162c	1381	break;
segundo	0:ac1725ba162c	1382	} else {
segundo	0:ac1725ba162c	1383	/* Either the lenghts are the same or the incoming
segundo	0:ac1725ba162c	1384	segment was smaller than the old one; in either
segundo	0:ac1725ba162c	1385	case, we ditch the incoming segment. */
segundo	0:ac1725ba162c	1386	break;
segundo	0:ac1725ba162c	1387	}
segundo	0:ac1725ba162c	1388	} else {
segundo	0:ac1725ba162c	1389	if (prev == NULL) {
segundo	0:ac1725ba162c	1390	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
segundo	0:ac1725ba162c	1391	/* The sequence number of the incoming segment is lower
segundo	0:ac1725ba162c	1392	than the sequence number of the first segment on the
segundo	0:ac1725ba162c	1393	queue. We put the incoming segment first on the
segundo	0:ac1725ba162c	1394	queue. */
segundo	0:ac1725ba162c	1395	cseg = tcp_seg_copy(&inseg);
segundo	0:ac1725ba162c	1396	if (cseg != NULL) {
segundo	0:ac1725ba162c	1397	pcb->ooseq = cseg;
segundo	0:ac1725ba162c	1398	tcp_oos_insert_segment(cseg, next);
segundo	0:ac1725ba162c	1399	}
segundo	0:ac1725ba162c	1400	break;
segundo	0:ac1725ba162c	1401	}
segundo	0:ac1725ba162c	1402	} else {
segundo	0:ac1725ba162c	1403	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
segundo	0:ac1725ba162c	1404	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
segundo	0:ac1725ba162c	1405	if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
segundo	0:ac1725ba162c	1406	/* The sequence number of the incoming segment is in
segundo	0:ac1725ba162c	1407	between the sequence numbers of the previous and
segundo	0:ac1725ba162c	1408	the next segment on ->ooseq. We trim trim the previous
segundo	0:ac1725ba162c	1409	segment, delete next segments that included in received segment
segundo	0:ac1725ba162c	1410	and trim received, if needed. */
segundo	0:ac1725ba162c	1411	cseg = tcp_seg_copy(&inseg);
segundo	0:ac1725ba162c	1412	if (cseg != NULL) {
segundo	0:ac1725ba162c	1413	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
segundo	0:ac1725ba162c	1414	/* We need to trim the prev segment. */
segundo	0:ac1725ba162c	1415	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
segundo	0:ac1725ba162c	1416	pbuf_realloc(prev->p, prev->len);
segundo	0:ac1725ba162c	1417	}
segundo	0:ac1725ba162c	1418	prev->next = cseg;
segundo	0:ac1725ba162c	1419	tcp_oos_insert_segment(cseg, next);
segundo	0:ac1725ba162c	1420	}
segundo	0:ac1725ba162c	1421	break;
segundo	0:ac1725ba162c	1422	}
segundo	0:ac1725ba162c	1423	}
segundo	0:ac1725ba162c	1424	/* If the "next" segment is the last segment on the
segundo	0:ac1725ba162c	1425	ooseq queue, we add the incoming segment to the end
segundo	0:ac1725ba162c	1426	of the list. */
segundo	0:ac1725ba162c	1427	if (next->next == NULL &&
segundo	0:ac1725ba162c	1428	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
segundo	0:ac1725ba162c	1429	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1430	/* segment "next" already contains all data */
segundo	0:ac1725ba162c	1431	break;
segundo	0:ac1725ba162c	1432	}
segundo	0:ac1725ba162c	1433	next->next = tcp_seg_copy(&inseg);
segundo	0:ac1725ba162c	1434	if (next->next != NULL) {
segundo	0:ac1725ba162c	1435	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
segundo	0:ac1725ba162c	1436	/* We need to trim the last segment. */
segundo	0:ac1725ba162c	1437	next->len = (u16_t)(seqno - next->tcphdr->seqno);
segundo	0:ac1725ba162c	1438	pbuf_realloc(next->p, next->len);
segundo	0:ac1725ba162c	1439	}
segundo	0:ac1725ba162c	1440	/* check if the remote side overruns our receive window */
segundo	0:ac1725ba162c	1441	if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
segundo	0:ac1725ba162c	1442	LWIP_DEBUGF(TCP_INPUT_DEBUG,
segundo	0:ac1725ba162c	1443	("tcp_receive: other end overran receive window"
segundo	0:ac1725ba162c	1444	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
segundo	0:ac1725ba162c	1445	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
segundo	0:ac1725ba162c	1446	if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
segundo	0:ac1725ba162c	1447	/* Must remove the FIN from the header as we're trimming
segundo	0:ac1725ba162c	1448	* that byte of sequence-space from the packet */
segundo	0:ac1725ba162c	1449	TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
segundo	0:ac1725ba162c	1450	}
segundo	0:ac1725ba162c	1451	/* Adjust length of segment to fit in the window. */
segundo	0:ac1725ba162c	1452	next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
segundo	0:ac1725ba162c	1453	pbuf_realloc(next->next->p, next->next->len);
segundo	0:ac1725ba162c	1454	tcplen = TCP_TCPLEN(next->next);
segundo	0:ac1725ba162c	1455	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
segundo	0:ac1725ba162c	1456	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
segundo	0:ac1725ba162c	1457	}
segundo	0:ac1725ba162c	1458	}
segundo	0:ac1725ba162c	1459	break;
segundo	0:ac1725ba162c	1460	}
segundo	0:ac1725ba162c	1461	}
segundo	0:ac1725ba162c	1462	prev = next;
segundo	0:ac1725ba162c	1463	}
segundo	0:ac1725ba162c	1464	}
segundo	0:ac1725ba162c	1465	#endif /* TCP_QUEUE_OOSEQ */
segundo	0:ac1725ba162c	1466
segundo	0:ac1725ba162c	1467	}
segundo	0:ac1725ba162c	1468	} else {
segundo	0:ac1725ba162c	1469	/* The incoming segment is not withing the window. */
segundo	0:ac1725ba162c	1470	tcp_send_empty_ack(pcb);
segundo	0:ac1725ba162c	1471	}
segundo	0:ac1725ba162c	1472	} else {
segundo	0:ac1725ba162c	1473	/* Segments with length 0 is taken care of here. Segments that
segundo	0:ac1725ba162c	1474	fall out of the window are ACKed. */
segundo	0:ac1725ba162c	1475	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
segundo	0:ac1725ba162c	1476	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
segundo	0:ac1725ba162c	1477	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
segundo	0:ac1725ba162c	1478	tcp_ack_now(pcb);
segundo	0:ac1725ba162c	1479	}
segundo	0:ac1725ba162c	1480	}
segundo	0:ac1725ba162c	1481	}
segundo	0:ac1725ba162c	1482
segundo	0:ac1725ba162c	1483	/**
segundo	0:ac1725ba162c	1484	* Parses the options contained in the incoming segment.
segundo	0:ac1725ba162c	1485	*
segundo	0:ac1725ba162c	1486	* Called from tcp_listen_input() and tcp_process().
segundo	0:ac1725ba162c	1487	* Currently, only the MSS option is supported!
segundo	0:ac1725ba162c	1488	*
segundo	0:ac1725ba162c	1489	* @param pcb the tcp_pcb for which a segment arrived
segundo	0:ac1725ba162c	1490	*/
segundo	0:ac1725ba162c	1491	static void
segundo	0:ac1725ba162c	1492	tcp_parseopt(struct tcp_pcb *pcb)
segundo	0:ac1725ba162c	1493	{
segundo	0:ac1725ba162c	1494	u16_t c, max_c;
segundo	0:ac1725ba162c	1495	u16_t mss;
segundo	0:ac1725ba162c	1496	u8_t *opts, opt;
segundo	0:ac1725ba162c	1497	#if LWIP_TCP_TIMESTAMPS
segundo	0:ac1725ba162c	1498	u32_t tsval;
segundo	0:ac1725ba162c	1499	#endif
segundo	0:ac1725ba162c	1500
segundo	0:ac1725ba162c	1501	opts = (u8_t *)tcphdr + TCP_HLEN;
segundo	0:ac1725ba162c	1502
segundo	0:ac1725ba162c	1503	/* Parse the TCP MSS option, if present. */
segundo	0:ac1725ba162c	1504	if(TCPH_HDRLEN(tcphdr) > 0x5) {
segundo	0:ac1725ba162c	1505	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
segundo	0:ac1725ba162c	1506	for (c = 0; c < max_c; ) {
segundo	0:ac1725ba162c	1507	opt = opts[c];
segundo	0:ac1725ba162c	1508	switch (opt) {
segundo	0:ac1725ba162c	1509	case 0x00:
segundo	0:ac1725ba162c	1510	/* End of options. */
segundo	0:ac1725ba162c	1511	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
segundo	0:ac1725ba162c	1512	return;
segundo	0:ac1725ba162c	1513	case 0x01:
segundo	0:ac1725ba162c	1514	/* NOP option. */
segundo	0:ac1725ba162c	1515	++c;
segundo	0:ac1725ba162c	1516	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
segundo	0:ac1725ba162c	1517	break;
segundo	0:ac1725ba162c	1518	case 0x02:
segundo	0:ac1725ba162c	1519	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
segundo	0:ac1725ba162c	1520	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
segundo	0:ac1725ba162c	1521	/* Bad length */
segundo	0:ac1725ba162c	1522	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
segundo	0:ac1725ba162c	1523	return;
segundo	0:ac1725ba162c	1524	}
segundo	0:ac1725ba162c	1525	/* An MSS option with the right option length. */
segundo	0:ac1725ba162c	1526	mss = (opts[c + 2] << 8) \| opts[c + 3];
segundo	0:ac1725ba162c	1527	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
segundo	0:ac1725ba162c	1528	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
segundo	0:ac1725ba162c	1529	/* Advance to next option */
segundo	0:ac1725ba162c	1530	c += 0x04;
segundo	0:ac1725ba162c	1531	break;
segundo	0:ac1725ba162c	1532	#if LWIP_TCP_TIMESTAMPS
segundo	0:ac1725ba162c	1533	case 0x08:
segundo	0:ac1725ba162c	1534	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
segundo	0:ac1725ba162c	1535	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
segundo	0:ac1725ba162c	1536	/* Bad length */
segundo	0:ac1725ba162c	1537	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
segundo	0:ac1725ba162c	1538	return;
segundo	0:ac1725ba162c	1539	}
segundo	0:ac1725ba162c	1540	/* TCP timestamp option with valid length */
segundo	0:ac1725ba162c	1541	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
segundo	0:ac1725ba162c	1542	(opts[c+4] << 16) \| (opts[c+5] << 24);
segundo	0:ac1725ba162c	1543	if (flags & TCP_SYN) {
segundo	0:ac1725ba162c	1544	pcb->ts_recent = ntohl(tsval);
segundo	0:ac1725ba162c	1545	pcb->flags \|= TF_TIMESTAMP;
segundo	0:ac1725ba162c	1546	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
segundo	0:ac1725ba162c	1547	pcb->ts_recent = ntohl(tsval);
segundo	0:ac1725ba162c	1548	}
segundo	0:ac1725ba162c	1549	/* Advance to next option */
segundo	0:ac1725ba162c	1550	c += 0x0A;
segundo	0:ac1725ba162c	1551	break;
segundo	0:ac1725ba162c	1552	#endif
segundo	0:ac1725ba162c	1553	default:
segundo	0:ac1725ba162c	1554	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
segundo	0:ac1725ba162c	1555	if (opts[c + 1] == 0) {
segundo	0:ac1725ba162c	1556	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
segundo	0:ac1725ba162c	1557	/* If the length field is zero, the options are malformed
segundo	0:ac1725ba162c	1558	and we don't process them further. */
segundo	0:ac1725ba162c	1559	return;
segundo	0:ac1725ba162c	1560	}
segundo	0:ac1725ba162c	1561	/* All other options have a length field, so that we easily
segundo	0:ac1725ba162c	1562	can skip past them. */
segundo	0:ac1725ba162c	1563	c += opts[c + 1];
segundo	0:ac1725ba162c	1564	}
segundo	0:ac1725ba162c	1565	}
segundo	0:ac1725ba162c	1566	}
segundo	0:ac1725ba162c	1567	}
segundo	0:ac1725ba162c	1568
segundo	0:ac1725ba162c	1569	#endif /* LWIP_TCP */

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Type:	Library
Created:	06 Mar 2013
Imports:	0
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Commits:	9
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lwip/core/tcp_in.c@0:ac1725ba162c, 2010-11-09 (annotated)

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