DS130x_I2CApp - This short program illustrates how to use the DS1…

Users » Yann » Code » DS130x_I2CApp

Yann Garcia / Mbed 2 deprecated DS130x_I2CApp

This short program illustrates how to use the DS130x_I2C library. My objective is to share the same RTC with Microchip 18F MCU.

Dependencies: mbed DebugLibrary

NetServices/lwip/core/tcp_in.c@1:995212d326ca, 2011-02-11 (annotated)

Committer:: Yann
Date:: Fri Feb 11 10:17:20 2011 +0000
Revision:: 1:995212d326ca
Parent:: 0:f30e2135b0db

V0.0.0.2

Who changed what in which revision?

User	Revision	Line number	New contents of line
Yann	0:f30e2135b0db	1	/**
Yann	0:f30e2135b0db	2	* @file
Yann	0:f30e2135b0db	3	* Transmission Control Protocol, incoming traffic
Yann	0:f30e2135b0db	4	*
Yann	0:f30e2135b0db	5	* The input processing functions of the TCP layer.
Yann	0:f30e2135b0db	6	*
Yann	0:f30e2135b0db	7	* These functions are generally called in the order (ip_input() ->)
Yann	0:f30e2135b0db	8	* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
Yann	0:f30e2135b0db	9	*
Yann	0:f30e2135b0db	10	*/
Yann	0:f30e2135b0db	11
Yann	0:f30e2135b0db	12	/*
Yann	0:f30e2135b0db	13	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
Yann	0:f30e2135b0db	14	* All rights reserved.
Yann	0:f30e2135b0db	15	*
Yann	0:f30e2135b0db	16	* Redistribution and use in source and binary forms, with or without modification,
Yann	0:f30e2135b0db	17	* are permitted provided that the following conditions are met:
Yann	0:f30e2135b0db	18	*
Yann	0:f30e2135b0db	19	* 1. Redistributions of source code must retain the above copyright notice,
Yann	0:f30e2135b0db	20	* this list of conditions and the following disclaimer.
Yann	0:f30e2135b0db	21	* 2. Redistributions in binary form must reproduce the above copyright notice,
Yann	0:f30e2135b0db	22	* this list of conditions and the following disclaimer in the documentation
Yann	0:f30e2135b0db	23	* and/or other materials provided with the distribution.
Yann	0:f30e2135b0db	24	* 3. The name of the author may not be used to endorse or promote products
Yann	0:f30e2135b0db	25	* derived from this software without specific prior written permission.
Yann	0:f30e2135b0db	26	*
Yann	0:f30e2135b0db	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
Yann	0:f30e2135b0db	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
Yann	0:f30e2135b0db	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
Yann	0:f30e2135b0db	30	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
Yann	0:f30e2135b0db	31	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
Yann	0:f30e2135b0db	32	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Yann	0:f30e2135b0db	33	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Yann	0:f30e2135b0db	34	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
Yann	0:f30e2135b0db	35	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
Yann	0:f30e2135b0db	36	* OF SUCH DAMAGE.
Yann	0:f30e2135b0db	37	*
Yann	0:f30e2135b0db	38	* This file is part of the lwIP TCP/IP stack.
Yann	0:f30e2135b0db	39	*
Yann	0:f30e2135b0db	40	* Author: Adam Dunkels <adam@sics.se>
Yann	0:f30e2135b0db	41	*
Yann	0:f30e2135b0db	42	*/
Yann	0:f30e2135b0db	43
Yann	0:f30e2135b0db	44	#include "lwip/opt.h"
Yann	0:f30e2135b0db	45
Yann	0:f30e2135b0db	46	#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
Yann	0:f30e2135b0db	47
Yann	0:f30e2135b0db	48	#include "lwip/tcp_impl.h"
Yann	0:f30e2135b0db	49	#include "lwip/def.h"
Yann	0:f30e2135b0db	50	#include "lwip/ip_addr.h"
Yann	0:f30e2135b0db	51	#include "lwip/netif.h"
Yann	0:f30e2135b0db	52	#include "lwip/mem.h"
Yann	0:f30e2135b0db	53	#include "lwip/memp.h"
Yann	0:f30e2135b0db	54	#include "lwip/inet_chksum.h"
Yann	0:f30e2135b0db	55	#include "lwip/stats.h"
Yann	0:f30e2135b0db	56	#include "lwip/snmp.h"
Yann	0:f30e2135b0db	57	#include "arch/perf.h"
Yann	0:f30e2135b0db	58
Yann	0:f30e2135b0db	59	/* These variables are global to all functions involved in the input
Yann	0:f30e2135b0db	60	processing of TCP segments. They are set by the tcp_input()
Yann	0:f30e2135b0db	61	function. */
Yann	0:f30e2135b0db	62	static struct tcp_seg inseg;
Yann	0:f30e2135b0db	63	static struct tcp_hdr *tcphdr;
Yann	0:f30e2135b0db	64	static struct ip_hdr *iphdr;
Yann	0:f30e2135b0db	65	static u32_t seqno, ackno;
Yann	0:f30e2135b0db	66	static u8_t flags;
Yann	0:f30e2135b0db	67	static u16_t tcplen;
Yann	0:f30e2135b0db	68
Yann	0:f30e2135b0db	69	static u8_t recv_flags;
Yann	0:f30e2135b0db	70	static struct pbuf *recv_data;
Yann	0:f30e2135b0db	71
Yann	0:f30e2135b0db	72	struct tcp_pcb *tcp_input_pcb;
Yann	0:f30e2135b0db	73
Yann	0:f30e2135b0db	74	/* Forward declarations. */
Yann	0:f30e2135b0db	75	static err_t tcp_process(struct tcp_pcb *pcb);
Yann	0:f30e2135b0db	76	static void tcp_receive(struct tcp_pcb *pcb);
Yann	0:f30e2135b0db	77	static void tcp_parseopt(struct tcp_pcb *pcb);
Yann	0:f30e2135b0db	78
Yann	0:f30e2135b0db	79	static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
Yann	0:f30e2135b0db	80	static err_t tcp_timewait_input(struct tcp_pcb *pcb);
Yann	0:f30e2135b0db	81
Yann	0:f30e2135b0db	82	/**
Yann	0:f30e2135b0db	83	* The initial input processing of TCP. It verifies the TCP header, demultiplexes
Yann	0:f30e2135b0db	84	* the segment between the PCBs and passes it on to tcp_process(), which implements
Yann	0:f30e2135b0db	85	* the TCP finite state machine. This function is called by the IP layer (in
Yann	0:f30e2135b0db	86	* ip_input()).
Yann	0:f30e2135b0db	87	*
Yann	0:f30e2135b0db	88	* @param p received TCP segment to process (p->payload pointing to the IP header)
Yann	0:f30e2135b0db	89	* @param inp network interface on which this segment was received
Yann	0:f30e2135b0db	90	*/
Yann	0:f30e2135b0db	91	void
Yann	0:f30e2135b0db	92	tcp_input(struct pbuf p, struct netif inp)
Yann	0:f30e2135b0db	93	{
Yann	0:f30e2135b0db	94	struct tcp_pcb pcb, prev;
Yann	0:f30e2135b0db	95	struct tcp_pcb_listen *lpcb;
Yann	0:f30e2135b0db	96	#if SO_REUSE
Yann	0:f30e2135b0db	97	struct tcp_pcb *lpcb_prev = NULL;
Yann	0:f30e2135b0db	98	struct tcp_pcb_listen *lpcb_any = NULL;
Yann	0:f30e2135b0db	99	#endif /* SO_REUSE */
Yann	0:f30e2135b0db	100	u8_t hdrlen;
Yann	0:f30e2135b0db	101	err_t err;
Yann	0:f30e2135b0db	102
Yann	0:f30e2135b0db	103	PERF_START;
Yann	0:f30e2135b0db	104
Yann	0:f30e2135b0db	105	TCP_STATS_INC(tcp.recv);
Yann	0:f30e2135b0db	106	snmp_inc_tcpinsegs();
Yann	0:f30e2135b0db	107
Yann	0:f30e2135b0db	108	iphdr = (struct ip_hdr *)p->payload;
Yann	0:f30e2135b0db	109	tcphdr = (struct tcp_hdr )((u8_t )p->payload + IPH_HL(iphdr) * 4);
Yann	0:f30e2135b0db	110
Yann	0:f30e2135b0db	111	#if TCP_INPUT_DEBUG
Yann	0:f30e2135b0db	112	tcp_debug_print(tcphdr);
Yann	0:f30e2135b0db	113	#endif
Yann	0:f30e2135b0db	114
Yann	0:f30e2135b0db	115	/* remove header from payload */
Yann	0:f30e2135b0db	116	if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) \|\| (p->tot_len < sizeof(struct tcp_hdr))) {
Yann	0:f30e2135b0db	117	/* drop short packets */
Yann	0:f30e2135b0db	118	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
Yann	0:f30e2135b0db	119	TCP_STATS_INC(tcp.lenerr);
Yann	0:f30e2135b0db	120	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	121	snmp_inc_tcpinerrs();
Yann	0:f30e2135b0db	122	pbuf_free(p);
Yann	0:f30e2135b0db	123	return;
Yann	0:f30e2135b0db	124	}
Yann	0:f30e2135b0db	125
Yann	0:f30e2135b0db	126	/* Don't even process incoming broadcasts/multicasts. */
Yann	0:f30e2135b0db	127	if (ip_addr_isbroadcast(&current_iphdr_dest, inp) \|\|
Yann	0:f30e2135b0db	128	ip_addr_ismulticast(&current_iphdr_dest)) {
Yann	0:f30e2135b0db	129	TCP_STATS_INC(tcp.proterr);
Yann	0:f30e2135b0db	130	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	131	snmp_inc_tcpinerrs();
Yann	0:f30e2135b0db	132	pbuf_free(p);
Yann	0:f30e2135b0db	133	return;
Yann	0:f30e2135b0db	134	}
Yann	0:f30e2135b0db	135
Yann	0:f30e2135b0db	136	#if CHECKSUM_CHECK_TCP
Yann	0:f30e2135b0db	137	/* Verify TCP checksum. */
Yann	0:f30e2135b0db	138	if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
Yann	0:f30e2135b0db	139	IP_PROTO_TCP, p->tot_len) != 0) {
Yann	0:f30e2135b0db	140	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
Yann	0:f30e2135b0db	141	inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
Yann	0:f30e2135b0db	142	IP_PROTO_TCP, p->tot_len)));
Yann	0:f30e2135b0db	143	#if TCP_DEBUG
Yann	0:f30e2135b0db	144	tcp_debug_print(tcphdr);
Yann	0:f30e2135b0db	145	#endif /* TCP_DEBUG */
Yann	0:f30e2135b0db	146	TCP_STATS_INC(tcp.chkerr);
Yann	0:f30e2135b0db	147	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	148	snmp_inc_tcpinerrs();
Yann	0:f30e2135b0db	149	pbuf_free(p);
Yann	0:f30e2135b0db	150	return;
Yann	0:f30e2135b0db	151	}
Yann	0:f30e2135b0db	152	#endif
Yann	0:f30e2135b0db	153
Yann	0:f30e2135b0db	154	/* Move the payload pointer in the pbuf so that it points to the
Yann	0:f30e2135b0db	155	TCP data instead of the TCP header. */
Yann	0:f30e2135b0db	156	hdrlen = TCPH_HDRLEN(tcphdr);
Yann	0:f30e2135b0db	157	if(pbuf_header(p, -(hdrlen * 4))){
Yann	0:f30e2135b0db	158	/* drop short packets */
Yann	0:f30e2135b0db	159	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
Yann	0:f30e2135b0db	160	TCP_STATS_INC(tcp.lenerr);
Yann	0:f30e2135b0db	161	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	162	snmp_inc_tcpinerrs();
Yann	0:f30e2135b0db	163	pbuf_free(p);
Yann	0:f30e2135b0db	164	return;
Yann	0:f30e2135b0db	165	}
Yann	0:f30e2135b0db	166
Yann	0:f30e2135b0db	167	/* Convert fields in TCP header to host byte order. */
Yann	0:f30e2135b0db	168	tcphdr->src = ntohs(tcphdr->src);
Yann	0:f30e2135b0db	169	tcphdr->dest = ntohs(tcphdr->dest);
Yann	0:f30e2135b0db	170	seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
Yann	0:f30e2135b0db	171	ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
Yann	0:f30e2135b0db	172	tcphdr->wnd = ntohs(tcphdr->wnd);
Yann	0:f30e2135b0db	173
Yann	0:f30e2135b0db	174	flags = TCPH_FLAGS(tcphdr);
Yann	0:f30e2135b0db	175	tcplen = p->tot_len + ((flags & (TCP_FIN \| TCP_SYN)) ? 1 : 0);
Yann	0:f30e2135b0db	176
Yann	0:f30e2135b0db	177	/* Demultiplex an incoming segment. First, we check if it is destined
Yann	0:f30e2135b0db	178	for an active connection. */
Yann	0:f30e2135b0db	179	prev = NULL;
Yann	0:f30e2135b0db	180
Yann	0:f30e2135b0db	181
Yann	0:f30e2135b0db	182	for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
Yann	0:f30e2135b0db	183	LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
Yann	0:f30e2135b0db	184	LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
Yann	0:f30e2135b0db	185	LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
Yann	0:f30e2135b0db	186	if (pcb->remote_port == tcphdr->src &&
Yann	0:f30e2135b0db	187	pcb->local_port == tcphdr->dest &&
Yann	0:f30e2135b0db	188	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
Yann	0:f30e2135b0db	189	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
Yann	0:f30e2135b0db	190
Yann	0:f30e2135b0db	191	/* Move this PCB to the front of the list so that subsequent
Yann	0:f30e2135b0db	192	lookups will be faster (we exploit locality in TCP segment
Yann	0:f30e2135b0db	193	arrivals). */
Yann	0:f30e2135b0db	194	LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
Yann	0:f30e2135b0db	195	if (prev != NULL) {
Yann	0:f30e2135b0db	196	prev->next = pcb->next;
Yann	0:f30e2135b0db	197	pcb->next = tcp_active_pcbs;
Yann	0:f30e2135b0db	198	tcp_active_pcbs = pcb;
Yann	0:f30e2135b0db	199	}
Yann	0:f30e2135b0db	200	LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
Yann	0:f30e2135b0db	201	break;
Yann	0:f30e2135b0db	202	}
Yann	0:f30e2135b0db	203	prev = pcb;
Yann	0:f30e2135b0db	204	}
Yann	0:f30e2135b0db	205
Yann	0:f30e2135b0db	206	if (pcb == NULL) {
Yann	0:f30e2135b0db	207	/* If it did not go to an active connection, we check the connections
Yann	0:f30e2135b0db	208	in the TIME-WAIT state. */
Yann	0:f30e2135b0db	209	for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
Yann	0:f30e2135b0db	210	LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
Yann	0:f30e2135b0db	211	if (pcb->remote_port == tcphdr->src &&
Yann	0:f30e2135b0db	212	pcb->local_port == tcphdr->dest &&
Yann	0:f30e2135b0db	213	ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
Yann	0:f30e2135b0db	214	ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
Yann	0:f30e2135b0db	215	/* We don't really care enough to move this PCB to the front
Yann	0:f30e2135b0db	216	of the list since we are not very likely to receive that
Yann	0:f30e2135b0db	217	many segments for connections in TIME-WAIT. */
Yann	0:f30e2135b0db	218	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
Yann	0:f30e2135b0db	219	tcp_timewait_input(pcb);
Yann	0:f30e2135b0db	220	pbuf_free(p);
Yann	0:f30e2135b0db	221	return;
Yann	0:f30e2135b0db	222	}
Yann	0:f30e2135b0db	223	}
Yann	0:f30e2135b0db	224
Yann	0:f30e2135b0db	225	/* Finally, if we still did not get a match, we check all PCBs that
Yann	0:f30e2135b0db	226	are LISTENing for incoming connections. */
Yann	0:f30e2135b0db	227	prev = NULL;
Yann	0:f30e2135b0db	228	for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
Yann	0:f30e2135b0db	229	if (lpcb->local_port == tcphdr->dest) {
Yann	0:f30e2135b0db	230	#if SO_REUSE
Yann	0:f30e2135b0db	231	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
Yann	0:f30e2135b0db	232	/* found an exact match */
Yann	0:f30e2135b0db	233	break;
Yann	0:f30e2135b0db	234	} else if(ip_addr_isany(&(lpcb->local_ip))) {
Yann	0:f30e2135b0db	235	/* found an ANY-match */
Yann	0:f30e2135b0db	236	lpcb_any = lpcb;
Yann	0:f30e2135b0db	237	lpcb_prev = prev;
Yann	0:f30e2135b0db	238	}
Yann	0:f30e2135b0db	239	#else /* SO_REUSE */
Yann	0:f30e2135b0db	240	if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) \|\|
Yann	0:f30e2135b0db	241	ip_addr_isany(&(lpcb->local_ip))) {
Yann	0:f30e2135b0db	242	/* found a match */
Yann	0:f30e2135b0db	243	break;
Yann	0:f30e2135b0db	244	}
Yann	0:f30e2135b0db	245	#endif /* SO_REUSE */
Yann	0:f30e2135b0db	246	}
Yann	0:f30e2135b0db	247	prev = (struct tcp_pcb *)lpcb;
Yann	0:f30e2135b0db	248	}
Yann	0:f30e2135b0db	249	#if SO_REUSE
Yann	0:f30e2135b0db	250	/* first try specific local IP */
Yann	0:f30e2135b0db	251	if (lpcb == NULL) {
Yann	0:f30e2135b0db	252	/* only pass to ANY if no specific local IP has been found */
Yann	0:f30e2135b0db	253	lpcb = lpcb_any;
Yann	0:f30e2135b0db	254	prev = lpcb_prev;
Yann	0:f30e2135b0db	255	}
Yann	0:f30e2135b0db	256	#endif /* SO_REUSE */
Yann	0:f30e2135b0db	257	if (lpcb != NULL) {
Yann	0:f30e2135b0db	258	/* Move this PCB to the front of the list so that subsequent
Yann	0:f30e2135b0db	259	lookups will be faster (we exploit locality in TCP segment
Yann	0:f30e2135b0db	260	arrivals). */
Yann	0:f30e2135b0db	261	if (prev != NULL) {
Yann	0:f30e2135b0db	262	((struct tcp_pcb_listen *)prev)->next = lpcb->next;
Yann	0:f30e2135b0db	263	/* our successor is the remainder of the listening list */
Yann	0:f30e2135b0db	264	lpcb->next = tcp_listen_pcbs.listen_pcbs;
Yann	0:f30e2135b0db	265	/* put this listening pcb at the head of the listening list */
Yann	0:f30e2135b0db	266	tcp_listen_pcbs.listen_pcbs = lpcb;
Yann	0:f30e2135b0db	267	}
Yann	0:f30e2135b0db	268
Yann	0:f30e2135b0db	269	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
Yann	0:f30e2135b0db	270	tcp_listen_input(lpcb);
Yann	0:f30e2135b0db	271	pbuf_free(p);
Yann	0:f30e2135b0db	272	return;
Yann	0:f30e2135b0db	273	}
Yann	0:f30e2135b0db	274	}
Yann	0:f30e2135b0db	275
Yann	0:f30e2135b0db	276	#if TCP_INPUT_DEBUG
Yann	0:f30e2135b0db	277	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
Yann	0:f30e2135b0db	278	tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
Yann	0:f30e2135b0db	279	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
Yann	0:f30e2135b0db	280	#endif /* TCP_INPUT_DEBUG */
Yann	0:f30e2135b0db	281
Yann	0:f30e2135b0db	282
Yann	0:f30e2135b0db	283	if (pcb != NULL) {
Yann	0:f30e2135b0db	284	/* The incoming segment belongs to a connection. */
Yann	0:f30e2135b0db	285	#if TCP_INPUT_DEBUG
Yann	0:f30e2135b0db	286	#if TCP_DEBUG
Yann	0:f30e2135b0db	287	tcp_debug_print_state(pcb->state);
Yann	0:f30e2135b0db	288	#endif /* TCP_DEBUG */
Yann	0:f30e2135b0db	289	#endif /* TCP_INPUT_DEBUG */
Yann	0:f30e2135b0db	290
Yann	0:f30e2135b0db	291	/* Set up a tcp_seg structure. */
Yann	0:f30e2135b0db	292	inseg.next = NULL;
Yann	0:f30e2135b0db	293	inseg.len = p->tot_len;
Yann	0:f30e2135b0db	294	inseg.dataptr = p->payload;
Yann	0:f30e2135b0db	295	inseg.p = p;
Yann	0:f30e2135b0db	296	inseg.tcphdr = tcphdr;
Yann	0:f30e2135b0db	297
Yann	0:f30e2135b0db	298	recv_data = NULL;
Yann	0:f30e2135b0db	299	recv_flags = 0;
Yann	0:f30e2135b0db	300
Yann	0:f30e2135b0db	301	/* If there is data which was previously "refused" by upper layer */
Yann	0:f30e2135b0db	302	if (pcb->refused_data != NULL) {
Yann	0:f30e2135b0db	303	/* Notify again application with data previously received. */
Yann	0:f30e2135b0db	304	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
Yann	0:f30e2135b0db	305	TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
Yann	0:f30e2135b0db	306	if (err == ERR_OK) {
Yann	0:f30e2135b0db	307	pcb->refused_data = NULL;
Yann	0:f30e2135b0db	308	} else {
Yann	0:f30e2135b0db	309	/* if err == ERR_ABRT, 'pcb' is already deallocated */
Yann	0:f30e2135b0db	310	/* drop incoming packets, because pcb is "full" */
Yann	0:f30e2135b0db	311	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
Yann	0:f30e2135b0db	312	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	313	snmp_inc_tcpinerrs();
Yann	0:f30e2135b0db	314	pbuf_free(p);
Yann	0:f30e2135b0db	315	return;
Yann	0:f30e2135b0db	316	}
Yann	0:f30e2135b0db	317	}
Yann	0:f30e2135b0db	318	tcp_input_pcb = pcb;
Yann	0:f30e2135b0db	319	err = tcp_process(pcb);
Yann	0:f30e2135b0db	320	/* A return value of ERR_ABRT means that tcp_abort() was called
Yann	0:f30e2135b0db	321	and that the pcb has been freed. If so, we don't do anything. */
Yann	0:f30e2135b0db	322	if (err != ERR_ABRT) {
Yann	0:f30e2135b0db	323	if (recv_flags & TF_RESET) {
Yann	0:f30e2135b0db	324	/* TF_RESET means that the connection was reset by the other
Yann	0:f30e2135b0db	325	end. We then call the error callback to inform the
Yann	0:f30e2135b0db	326	application that the connection is dead before we
Yann	0:f30e2135b0db	327	deallocate the PCB. */
Yann	0:f30e2135b0db	328	TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
Yann	0:f30e2135b0db	329	tcp_pcb_remove(&tcp_active_pcbs, pcb);
Yann	0:f30e2135b0db	330	memp_free(MEMP_TCP_PCB, pcb);
Yann	0:f30e2135b0db	331	} else if (recv_flags & TF_CLOSED) {
Yann	0:f30e2135b0db	332	/* The connection has been closed and we will deallocate the
Yann	0:f30e2135b0db	333	PCB. */
Yann	0:f30e2135b0db	334	tcp_pcb_remove(&tcp_active_pcbs, pcb);
Yann	0:f30e2135b0db	335	memp_free(MEMP_TCP_PCB, pcb);
Yann	0:f30e2135b0db	336	} else {
Yann	0:f30e2135b0db	337	err = ERR_OK;
Yann	0:f30e2135b0db	338	/* If the application has registered a "sent" function to be
Yann	0:f30e2135b0db	339	called when new send buffer space is available, we call it
Yann	0:f30e2135b0db	340	now. */
Yann	0:f30e2135b0db	341	if (pcb->acked > 0) {
Yann	0:f30e2135b0db	342	TCP_EVENT_SENT(pcb, pcb->acked, err);
Yann	0:f30e2135b0db	343	if (err == ERR_ABRT) {
Yann	0:f30e2135b0db	344	goto aborted;
Yann	0:f30e2135b0db	345	}
Yann	0:f30e2135b0db	346	}
Yann	0:f30e2135b0db	347
Yann	0:f30e2135b0db	348	if (recv_data != NULL) {
Yann	0:f30e2135b0db	349	if (pcb->flags & TF_RXCLOSED) {
Yann	0:f30e2135b0db	350	/* received data although already closed -> abort (send RST) to
Yann	0:f30e2135b0db	351	notify the remote host that not all data has been processed */
Yann	0:f30e2135b0db	352	pbuf_free(recv_data);
Yann	0:f30e2135b0db	353	tcp_abort(pcb);
Yann	0:f30e2135b0db	354	goto aborted;
Yann	0:f30e2135b0db	355	}
Yann	0:f30e2135b0db	356	if (flags & TCP_PSH) {
Yann	0:f30e2135b0db	357	recv_data->flags \|= PBUF_FLAG_PUSH;
Yann	0:f30e2135b0db	358	}
Yann	0:f30e2135b0db	359
Yann	0:f30e2135b0db	360	/* Notify application that data has been received. */
Yann	0:f30e2135b0db	361	TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
Yann	0:f30e2135b0db	362	if (err == ERR_ABRT) {
Yann	0:f30e2135b0db	363	goto aborted;
Yann	0:f30e2135b0db	364	}
Yann	0:f30e2135b0db	365
Yann	0:f30e2135b0db	366	/* If the upper layer can't receive this data, store it */
Yann	0:f30e2135b0db	367	if (err != ERR_OK) {
Yann	0:f30e2135b0db	368	pcb->refused_data = recv_data;
Yann	0:f30e2135b0db	369	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
Yann	0:f30e2135b0db	370	}
Yann	0:f30e2135b0db	371	}
Yann	0:f30e2135b0db	372
Yann	0:f30e2135b0db	373	/* If a FIN segment was received, we call the callback
Yann	0:f30e2135b0db	374	function with a NULL buffer to indicate EOF. */
Yann	0:f30e2135b0db	375	if (recv_flags & TF_GOT_FIN) {
Yann	0:f30e2135b0db	376	/* correct rcv_wnd as the application won't call tcp_recved()
Yann	0:f30e2135b0db	377	for the FIN's seqno */
Yann	0:f30e2135b0db	378	if (pcb->rcv_wnd != TCP_WND) {
Yann	0:f30e2135b0db	379	pcb->rcv_wnd++;
Yann	0:f30e2135b0db	380	}
Yann	0:f30e2135b0db	381	TCP_EVENT_CLOSED(pcb, err);
Yann	0:f30e2135b0db	382	if (err == ERR_ABRT) {
Yann	0:f30e2135b0db	383	goto aborted;
Yann	0:f30e2135b0db	384	}
Yann	0:f30e2135b0db	385	}
Yann	0:f30e2135b0db	386
Yann	0:f30e2135b0db	387	tcp_input_pcb = NULL;
Yann	0:f30e2135b0db	388	/* Try to send something out. */
Yann	0:f30e2135b0db	389	tcp_output(pcb);
Yann	0:f30e2135b0db	390	#if TCP_INPUT_DEBUG
Yann	0:f30e2135b0db	391	#if TCP_DEBUG
Yann	0:f30e2135b0db	392	tcp_debug_print_state(pcb->state);
Yann	0:f30e2135b0db	393	#endif /* TCP_DEBUG */
Yann	0:f30e2135b0db	394	#endif /* TCP_INPUT_DEBUG */
Yann	0:f30e2135b0db	395	}
Yann	0:f30e2135b0db	396	}
Yann	0:f30e2135b0db	397	/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
Yann	0:f30e2135b0db	398	Below this line, 'pcb' may not be dereferenced! */
Yann	0:f30e2135b0db	399	aborted:
Yann	0:f30e2135b0db	400	tcp_input_pcb = NULL;
Yann	0:f30e2135b0db	401	recv_data = NULL;
Yann	0:f30e2135b0db	402
Yann	0:f30e2135b0db	403	/* give up our reference to inseg.p */
Yann	0:f30e2135b0db	404	if (inseg.p != NULL)
Yann	0:f30e2135b0db	405	{
Yann	0:f30e2135b0db	406	pbuf_free(inseg.p);
Yann	0:f30e2135b0db	407	inseg.p = NULL;
Yann	0:f30e2135b0db	408	}
Yann	0:f30e2135b0db	409	} else {
Yann	0:f30e2135b0db	410
Yann	0:f30e2135b0db	411	/* If no matching PCB was found, send a TCP RST (reset) to the
Yann	0:f30e2135b0db	412	sender. */
Yann	0:f30e2135b0db	413	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
Yann	0:f30e2135b0db	414	if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
Yann	0:f30e2135b0db	415	TCP_STATS_INC(tcp.proterr);
Yann	0:f30e2135b0db	416	TCP_STATS_INC(tcp.drop);
Yann	0:f30e2135b0db	417	tcp_rst(ackno, seqno + tcplen,
Yann	0:f30e2135b0db	418	ip_current_dest_addr(), ip_current_src_addr(),
Yann	0:f30e2135b0db	419	tcphdr->dest, tcphdr->src);
Yann	0:f30e2135b0db	420	}
Yann	0:f30e2135b0db	421	pbuf_free(p);
Yann	0:f30e2135b0db	422	}
Yann	0:f30e2135b0db	423
Yann	0:f30e2135b0db	424	LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
Yann	0:f30e2135b0db	425	PERF_STOP("tcp_input");
Yann	0:f30e2135b0db	426	}
Yann	0:f30e2135b0db	427
Yann	0:f30e2135b0db	428	/**
Yann	0:f30e2135b0db	429	* Called by tcp_input() when a segment arrives for a listening
Yann	0:f30e2135b0db	430	* connection (from tcp_input()).
Yann	0:f30e2135b0db	431	*
Yann	0:f30e2135b0db	432	* @param pcb the tcp_pcb_listen for which a segment arrived
Yann	0:f30e2135b0db	433	* @return ERR_OK if the segment was processed
Yann	0:f30e2135b0db	434	* another err_t on error
Yann	0:f30e2135b0db	435	*
Yann	0:f30e2135b0db	436	* @note the return value is not (yet?) used in tcp_input()
Yann	0:f30e2135b0db	437	* @note the segment which arrived is saved in global variables, therefore only the pcb
Yann	0:f30e2135b0db	438	* involved is passed as a parameter to this function
Yann	0:f30e2135b0db	439	*/
Yann	0:f30e2135b0db	440	static err_t
Yann	0:f30e2135b0db	441	tcp_listen_input(struct tcp_pcb_listen *pcb)
Yann	0:f30e2135b0db	442	{
Yann	0:f30e2135b0db	443	struct tcp_pcb *npcb;
Yann	0:f30e2135b0db	444	err_t rc;
Yann	0:f30e2135b0db	445
Yann	0:f30e2135b0db	446	/* In the LISTEN state, we check for incoming SYN segments,
Yann	0:f30e2135b0db	447	creates a new PCB, and responds with a SYN\|ACK. */
Yann	0:f30e2135b0db	448	if (flags & TCP_ACK) {
Yann	0:f30e2135b0db	449	/* For incoming segments with the ACK flag set, respond with a
Yann	0:f30e2135b0db	450	RST. */
Yann	0:f30e2135b0db	451	LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
Yann	0:f30e2135b0db	452	tcp_rst(ackno + 1, seqno + tcplen,
Yann	0:f30e2135b0db	453	ip_current_dest_addr(), ip_current_src_addr(),
Yann	0:f30e2135b0db	454	tcphdr->dest, tcphdr->src);
Yann	0:f30e2135b0db	455	} else if (flags & TCP_SYN) {
Yann	0:f30e2135b0db	456	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
Yann	0:f30e2135b0db	457	#if TCP_LISTEN_BACKLOG
Yann	0:f30e2135b0db	458	if (pcb->accepts_pending >= pcb->backlog) {
Yann	0:f30e2135b0db	459	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
Yann	0:f30e2135b0db	460	return ERR_ABRT;
Yann	0:f30e2135b0db	461	}
Yann	0:f30e2135b0db	462	#endif /* TCP_LISTEN_BACKLOG */
Yann	0:f30e2135b0db	463	npcb = tcp_alloc(pcb->prio);
Yann	0:f30e2135b0db	464	/* If a new PCB could not be created (probably due to lack of memory),
Yann	0:f30e2135b0db	465	we don't do anything, but rely on the sender will retransmit the
Yann	0:f30e2135b0db	466	SYN at a time when we have more memory available. */
Yann	0:f30e2135b0db	467	if (npcb == NULL) {
Yann	0:f30e2135b0db	468	LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
Yann	0:f30e2135b0db	469	TCP_STATS_INC(tcp.memerr);
Yann	0:f30e2135b0db	470	return ERR_MEM;
Yann	0:f30e2135b0db	471	}
Yann	0:f30e2135b0db	472	#if TCP_LISTEN_BACKLOG
Yann	0:f30e2135b0db	473	pcb->accepts_pending++;
Yann	0:f30e2135b0db	474	#endif /* TCP_LISTEN_BACKLOG */
Yann	0:f30e2135b0db	475	/* Set up the new PCB. */
Yann	0:f30e2135b0db	476	ip_addr_copy(npcb->local_ip, current_iphdr_dest);
Yann	0:f30e2135b0db	477	npcb->local_port = pcb->local_port;
Yann	0:f30e2135b0db	478	ip_addr_copy(npcb->remote_ip, current_iphdr_src);
Yann	0:f30e2135b0db	479	npcb->remote_port = tcphdr->src;
Yann	0:f30e2135b0db	480	npcb->state = SYN_RCVD;
Yann	0:f30e2135b0db	481	npcb->rcv_nxt = seqno + 1;
Yann	0:f30e2135b0db	482	npcb->rcv_ann_right_edge = npcb->rcv_nxt;
Yann	0:f30e2135b0db	483	npcb->snd_wnd = tcphdr->wnd;
Yann	0:f30e2135b0db	484	npcb->ssthresh = npcb->snd_wnd;
Yann	0:f30e2135b0db	485	npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
Yann	0:f30e2135b0db	486	npcb->callback_arg = pcb->callback_arg;
Yann	0:f30e2135b0db	487	#if LWIP_CALLBACK_API
Yann	0:f30e2135b0db	488	npcb->accept = pcb->accept;
Yann	0:f30e2135b0db	489	#endif /* LWIP_CALLBACK_API */
Yann	0:f30e2135b0db	490	/* inherit socket options */
Yann	0:f30e2135b0db	491	npcb->so_options = pcb->so_options & SOF_INHERITED;
Yann	0:f30e2135b0db	492	/* Register the new PCB so that we can begin receiving segments
Yann	0:f30e2135b0db	493	for it. */
Yann	0:f30e2135b0db	494	TCP_REG(&tcp_active_pcbs, npcb);
Yann	0:f30e2135b0db	495
Yann	0:f30e2135b0db	496	/* Parse any options in the SYN. */
Yann	0:f30e2135b0db	497	tcp_parseopt(npcb);
Yann	0:f30e2135b0db	498	#if TCP_CALCULATE_EFF_SEND_MSS
Yann	0:f30e2135b0db	499	npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
Yann	0:f30e2135b0db	500	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
Yann	0:f30e2135b0db	501
Yann	0:f30e2135b0db	502	snmp_inc_tcppassiveopens();
Yann	0:f30e2135b0db	503
Yann	0:f30e2135b0db	504	/* Send a SYN\|ACK together with the MSS option. */
Yann	0:f30e2135b0db	505	rc = tcp_enqueue_flags(npcb, TCP_SYN \| TCP_ACK);
Yann	0:f30e2135b0db	506	if (rc != ERR_OK) {
Yann	0:f30e2135b0db	507	tcp_abandon(npcb, 0);
Yann	0:f30e2135b0db	508	return rc;
Yann	0:f30e2135b0db	509	}
Yann	0:f30e2135b0db	510	return tcp_output(npcb);
Yann	0:f30e2135b0db	511	}
Yann	0:f30e2135b0db	512	return ERR_OK;
Yann	0:f30e2135b0db	513	}
Yann	0:f30e2135b0db	514
Yann	0:f30e2135b0db	515	/**
Yann	0:f30e2135b0db	516	* Called by tcp_input() when a segment arrives for a connection in
Yann	0:f30e2135b0db	517	* TIME_WAIT.
Yann	0:f30e2135b0db	518	*
Yann	0:f30e2135b0db	519	* @param pcb the tcp_pcb for which a segment arrived
Yann	0:f30e2135b0db	520	*
Yann	0:f30e2135b0db	521	* @note the segment which arrived is saved in global variables, therefore only the pcb
Yann	0:f30e2135b0db	522	* involved is passed as a parameter to this function
Yann	0:f30e2135b0db	523	*/
Yann	0:f30e2135b0db	524	static err_t
Yann	0:f30e2135b0db	525	tcp_timewait_input(struct tcp_pcb *pcb)
Yann	0:f30e2135b0db	526	{
Yann	0:f30e2135b0db	527	/* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
Yann	0:f30e2135b0db	528	/* RFC 793 3.9 Event Processing - Segment Arrives:
Yann	0:f30e2135b0db	529	* - first check sequence number - we skip that one in TIME_WAIT (always
Yann	0:f30e2135b0db	530	* acceptable since we only send ACKs)
Yann	0:f30e2135b0db	531	* - second check the RST bit (... return) */
Yann	0:f30e2135b0db	532	if (flags & TCP_RST) {
Yann	0:f30e2135b0db	533	return ERR_OK;
Yann	0:f30e2135b0db	534	}
Yann	0:f30e2135b0db	535	/* - fourth, check the SYN bit, */
Yann	0:f30e2135b0db	536	if (flags & TCP_SYN) {
Yann	0:f30e2135b0db	537	/* If an incoming segment is not acceptable, an acknowledgment
Yann	0:f30e2135b0db	538	should be sent in reply */
Yann	0:f30e2135b0db	539	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
Yann	0:f30e2135b0db	540	/* If the SYN is in the window it is an error, send a reset */
Yann	0:f30e2135b0db	541	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
Yann	0:f30e2135b0db	542	tcphdr->dest, tcphdr->src);
Yann	0:f30e2135b0db	543	return ERR_OK;
Yann	0:f30e2135b0db	544	}
Yann	0:f30e2135b0db	545	} else if (flags & TCP_FIN) {
Yann	0:f30e2135b0db	546	/* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
Yann	0:f30e2135b0db	547	Restart the 2 MSL time-wait timeout.*/
Yann	0:f30e2135b0db	548	pcb->tmr = tcp_ticks;
Yann	0:f30e2135b0db	549	}
Yann	0:f30e2135b0db	550
Yann	0:f30e2135b0db	551	if ((tcplen > 0)) {
Yann	0:f30e2135b0db	552	/* Acknowledge data, FIN or out-of-window SYN */
Yann	0:f30e2135b0db	553	pcb->flags \|= TF_ACK_NOW;
Yann	0:f30e2135b0db	554	return tcp_output(pcb);
Yann	0:f30e2135b0db	555	}
Yann	0:f30e2135b0db	556	return ERR_OK;
Yann	0:f30e2135b0db	557	}
Yann	0:f30e2135b0db	558
Yann	0:f30e2135b0db	559	/**
Yann	0:f30e2135b0db	560	* Implements the TCP state machine. Called by tcp_input. In some
Yann	0:f30e2135b0db	561	* states tcp_receive() is called to receive data. The tcp_seg
Yann	0:f30e2135b0db	562	* argument will be freed by the caller (tcp_input()) unless the
Yann	0:f30e2135b0db	563	* recv_data pointer in the pcb is set.
Yann	0:f30e2135b0db	564	*
Yann	0:f30e2135b0db	565	* @param pcb the tcp_pcb for which a segment arrived
Yann	0:f30e2135b0db	566	*
Yann	0:f30e2135b0db	567	* @note the segment which arrived is saved in global variables, therefore only the pcb
Yann	0:f30e2135b0db	568	* involved is passed as a parameter to this function
Yann	0:f30e2135b0db	569	*/
Yann	0:f30e2135b0db	570	static err_t
Yann	0:f30e2135b0db	571	tcp_process(struct tcp_pcb *pcb)
Yann	0:f30e2135b0db	572	{
Yann	0:f30e2135b0db	573	struct tcp_seg *rseg;
Yann	0:f30e2135b0db	574	u8_t acceptable = 0;
Yann	0:f30e2135b0db	575	err_t err;
Yann	0:f30e2135b0db	576
Yann	0:f30e2135b0db	577	err = ERR_OK;
Yann	0:f30e2135b0db	578
Yann	0:f30e2135b0db	579	/* Process incoming RST segments. */
Yann	0:f30e2135b0db	580	if (flags & TCP_RST) {
Yann	0:f30e2135b0db	581	/* First, determine if the reset is acceptable. */
Yann	0:f30e2135b0db	582	if (pcb->state == SYN_SENT) {
Yann	0:f30e2135b0db	583	if (ackno == pcb->snd_nxt) {
Yann	0:f30e2135b0db	584	acceptable = 1;
Yann	0:f30e2135b0db	585	}
Yann	0:f30e2135b0db	586	} else {
Yann	0:f30e2135b0db	587	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
Yann	0:f30e2135b0db	588	pcb->rcv_nxt+pcb->rcv_wnd)) {
Yann	0:f30e2135b0db	589	acceptable = 1;
Yann	0:f30e2135b0db	590	}
Yann	0:f30e2135b0db	591	}
Yann	0:f30e2135b0db	592
Yann	0:f30e2135b0db	593	if (acceptable) {
Yann	0:f30e2135b0db	594	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
Yann	0:f30e2135b0db	595	LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
Yann	0:f30e2135b0db	596	recv_flags \|= TF_RESET;
Yann	0:f30e2135b0db	597	pcb->flags &= ~TF_ACK_DELAY;
Yann	0:f30e2135b0db	598	return ERR_RST;
Yann	0:f30e2135b0db	599	} else {
Yann	0:f30e2135b0db	600	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
Yann	0:f30e2135b0db	601	seqno, pcb->rcv_nxt));
Yann	0:f30e2135b0db	602	LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
Yann	0:f30e2135b0db	603	seqno, pcb->rcv_nxt));
Yann	0:f30e2135b0db	604	return ERR_OK;
Yann	0:f30e2135b0db	605	}
Yann	0:f30e2135b0db	606	}
Yann	0:f30e2135b0db	607
Yann	0:f30e2135b0db	608	if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
Yann	0:f30e2135b0db	609	/* Cope with new connection attempt after remote end crashed */
Yann	0:f30e2135b0db	610	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	611	return ERR_OK;
Yann	0:f30e2135b0db	612	}
Yann	0:f30e2135b0db	613
Yann	0:f30e2135b0db	614	if ((pcb->flags & TF_RXCLOSED) == 0) {
Yann	0:f30e2135b0db	615	/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
Yann	0:f30e2135b0db	616	pcb->tmr = tcp_ticks;
Yann	0:f30e2135b0db	617	}
Yann	0:f30e2135b0db	618	pcb->keep_cnt_sent = 0;
Yann	0:f30e2135b0db	619
Yann	0:f30e2135b0db	620	tcp_parseopt(pcb);
Yann	0:f30e2135b0db	621
Yann	0:f30e2135b0db	622	/* Do different things depending on the TCP state. */
Yann	0:f30e2135b0db	623	switch (pcb->state) {
Yann	0:f30e2135b0db	624	case SYN_SENT:
Yann	0:f30e2135b0db	625	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
Yann	0:f30e2135b0db	626	pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
Yann	0:f30e2135b0db	627	/* received SYN ACK with expected sequence number? */
Yann	0:f30e2135b0db	628	if ((flags & TCP_ACK) && (flags & TCP_SYN)
Yann	0:f30e2135b0db	629	&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
Yann	0:f30e2135b0db	630	pcb->snd_buf++;
Yann	0:f30e2135b0db	631	pcb->rcv_nxt = seqno + 1;
Yann	0:f30e2135b0db	632	pcb->rcv_ann_right_edge = pcb->rcv_nxt;
Yann	0:f30e2135b0db	633	pcb->lastack = ackno;
Yann	0:f30e2135b0db	634	pcb->snd_wnd = tcphdr->wnd;
Yann	0:f30e2135b0db	635	pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
Yann	0:f30e2135b0db	636	pcb->state = ESTABLISHED;
Yann	0:f30e2135b0db	637
Yann	0:f30e2135b0db	638	#if TCP_CALCULATE_EFF_SEND_MSS
Yann	0:f30e2135b0db	639	pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
Yann	0:f30e2135b0db	640	#endif /* TCP_CALCULATE_EFF_SEND_MSS */
Yann	0:f30e2135b0db	641
Yann	0:f30e2135b0db	642	/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
Yann	0:f30e2135b0db	643	* but for the default value of pcb->mss) */
Yann	0:f30e2135b0db	644	pcb->ssthresh = pcb->mss * 10;
Yann	0:f30e2135b0db	645
Yann	0:f30e2135b0db	646	pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
Yann	0:f30e2135b0db	647	LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
Yann	0:f30e2135b0db	648	--pcb->snd_queuelen;
Yann	0:f30e2135b0db	649	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
Yann	0:f30e2135b0db	650	rseg = pcb->unacked;
Yann	0:f30e2135b0db	651	pcb->unacked = rseg->next;
Yann	0:f30e2135b0db	652
Yann	0:f30e2135b0db	653	/* If there's nothing left to acknowledge, stop the retransmit
Yann	0:f30e2135b0db	654	timer, otherwise reset it to start again */
Yann	0:f30e2135b0db	655	if(pcb->unacked == NULL)
Yann	0:f30e2135b0db	656	pcb->rtime = -1;
Yann	0:f30e2135b0db	657	else {
Yann	0:f30e2135b0db	658	pcb->rtime = 0;
Yann	0:f30e2135b0db	659	pcb->nrtx = 0;
Yann	0:f30e2135b0db	660	}
Yann	0:f30e2135b0db	661
Yann	0:f30e2135b0db	662	tcp_seg_free(rseg);
Yann	0:f30e2135b0db	663
Yann	0:f30e2135b0db	664	/* Call the user specified function to call when sucessfully
Yann	0:f30e2135b0db	665	* connected. */
Yann	0:f30e2135b0db	666	TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
Yann	0:f30e2135b0db	667	if (err == ERR_ABRT) {
Yann	0:f30e2135b0db	668	return ERR_ABRT;
Yann	0:f30e2135b0db	669	}
Yann	0:f30e2135b0db	670	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	671	}
Yann	0:f30e2135b0db	672	/* received ACK? possibly a half-open connection */
Yann	0:f30e2135b0db	673	else if (flags & TCP_ACK) {
Yann	0:f30e2135b0db	674	/* send a RST to bring the other side in a non-synchronized state. */
Yann	0:f30e2135b0db	675	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
Yann	0:f30e2135b0db	676	tcphdr->dest, tcphdr->src);
Yann	0:f30e2135b0db	677	}
Yann	0:f30e2135b0db	678	break;
Yann	0:f30e2135b0db	679	case SYN_RCVD:
Yann	0:f30e2135b0db	680	if (flags & TCP_ACK) {
Yann	0:f30e2135b0db	681	/* expected ACK number? */
Yann	0:f30e2135b0db	682	if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
Yann	0:f30e2135b0db	683	u16_t old_cwnd;
Yann	0:f30e2135b0db	684	pcb->state = ESTABLISHED;
Yann	0:f30e2135b0db	685	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
Yann	0:f30e2135b0db	686	#if LWIP_CALLBACK_API
Yann	0:f30e2135b0db	687	LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
Yann	0:f30e2135b0db	688	#endif
Yann	0:f30e2135b0db	689	/* Call the accept function. */
Yann	0:f30e2135b0db	690	TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
Yann	0:f30e2135b0db	691	if (err != ERR_OK) {
Yann	0:f30e2135b0db	692	/* If the accept function returns with an error, we abort
Yann	0:f30e2135b0db	693	* the connection. */
Yann	0:f30e2135b0db	694	/* Already aborted? */
Yann	0:f30e2135b0db	695	if (err != ERR_ABRT) {
Yann	0:f30e2135b0db	696	tcp_abort(pcb);
Yann	0:f30e2135b0db	697	}
Yann	0:f30e2135b0db	698	return ERR_ABRT;
Yann	0:f30e2135b0db	699	}
Yann	0:f30e2135b0db	700	old_cwnd = pcb->cwnd;
Yann	0:f30e2135b0db	701	/* If there was any data contained within this ACK,
Yann	0:f30e2135b0db	702	* we'd better pass it on to the application as well. */
Yann	0:f30e2135b0db	703	tcp_receive(pcb);
Yann	0:f30e2135b0db	704
Yann	0:f30e2135b0db	705	/* Prevent ACK for SYN to generate a sent event */
Yann	0:f30e2135b0db	706	if (pcb->acked != 0) {
Yann	0:f30e2135b0db	707	pcb->acked--;
Yann	0:f30e2135b0db	708	}
Yann	0:f30e2135b0db	709
Yann	0:f30e2135b0db	710	pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
Yann	0:f30e2135b0db	711
Yann	0:f30e2135b0db	712	if (recv_flags & TF_GOT_FIN) {
Yann	0:f30e2135b0db	713	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	714	pcb->state = CLOSE_WAIT;
Yann	0:f30e2135b0db	715	}
Yann	0:f30e2135b0db	716	} else {
Yann	0:f30e2135b0db	717	/* incorrect ACK number, send RST */
Yann	0:f30e2135b0db	718	tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
Yann	0:f30e2135b0db	719	tcphdr->dest, tcphdr->src);
Yann	0:f30e2135b0db	720	}
Yann	0:f30e2135b0db	721	} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
Yann	0:f30e2135b0db	722	/* Looks like another copy of the SYN - retransmit our SYN-ACK */
Yann	0:f30e2135b0db	723	tcp_rexmit(pcb);
Yann	0:f30e2135b0db	724	}
Yann	0:f30e2135b0db	725	break;
Yann	0:f30e2135b0db	726	case CLOSE_WAIT:
Yann	0:f30e2135b0db	727	/* FALLTHROUGH */
Yann	0:f30e2135b0db	728	case ESTABLISHED:
Yann	0:f30e2135b0db	729	tcp_receive(pcb);
Yann	0:f30e2135b0db	730	if (recv_flags & TF_GOT_FIN) { /* passive close */
Yann	0:f30e2135b0db	731	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	732	pcb->state = CLOSE_WAIT;
Yann	0:f30e2135b0db	733	}
Yann	0:f30e2135b0db	734	break;
Yann	0:f30e2135b0db	735	case FIN_WAIT_1:
Yann	0:f30e2135b0db	736	tcp_receive(pcb);
Yann	0:f30e2135b0db	737	if (recv_flags & TF_GOT_FIN) {
Yann	0:f30e2135b0db	738	if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
Yann	0:f30e2135b0db	739	LWIP_DEBUGF(TCP_DEBUG,
Yann	0:f30e2135b0db	740	("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
Yann	0:f30e2135b0db	741	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	742	tcp_pcb_purge(pcb);
Yann	0:f30e2135b0db	743	TCP_RMV(&tcp_active_pcbs, pcb);
Yann	0:f30e2135b0db	744	pcb->state = TIME_WAIT;
Yann	0:f30e2135b0db	745	TCP_REG(&tcp_tw_pcbs, pcb);
Yann	0:f30e2135b0db	746	} else {
Yann	0:f30e2135b0db	747	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	748	pcb->state = CLOSING;
Yann	0:f30e2135b0db	749	}
Yann	0:f30e2135b0db	750	} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
Yann	0:f30e2135b0db	751	pcb->state = FIN_WAIT_2;
Yann	0:f30e2135b0db	752	}
Yann	0:f30e2135b0db	753	break;
Yann	0:f30e2135b0db	754	case FIN_WAIT_2:
Yann	0:f30e2135b0db	755	tcp_receive(pcb);
Yann	0:f30e2135b0db	756	if (recv_flags & TF_GOT_FIN) {
Yann	0:f30e2135b0db	757	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
Yann	0:f30e2135b0db	758	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	759	tcp_pcb_purge(pcb);
Yann	0:f30e2135b0db	760	TCP_RMV(&tcp_active_pcbs, pcb);
Yann	0:f30e2135b0db	761	pcb->state = TIME_WAIT;
Yann	0:f30e2135b0db	762	TCP_REG(&tcp_tw_pcbs, pcb);
Yann	0:f30e2135b0db	763	}
Yann	0:f30e2135b0db	764	break;
Yann	0:f30e2135b0db	765	case CLOSING:
Yann	0:f30e2135b0db	766	tcp_receive(pcb);
Yann	0:f30e2135b0db	767	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
Yann	0:f30e2135b0db	768	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
Yann	0:f30e2135b0db	769	tcp_pcb_purge(pcb);
Yann	0:f30e2135b0db	770	TCP_RMV(&tcp_active_pcbs, pcb);
Yann	0:f30e2135b0db	771	pcb->state = TIME_WAIT;
Yann	0:f30e2135b0db	772	TCP_REG(&tcp_tw_pcbs, pcb);
Yann	0:f30e2135b0db	773	}
Yann	0:f30e2135b0db	774	break;
Yann	0:f30e2135b0db	775	case LAST_ACK:
Yann	0:f30e2135b0db	776	tcp_receive(pcb);
Yann	0:f30e2135b0db	777	if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
Yann	0:f30e2135b0db	778	LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
Yann	0:f30e2135b0db	779	/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
Yann	0:f30e2135b0db	780	recv_flags \|= TF_CLOSED;
Yann	0:f30e2135b0db	781	}
Yann	0:f30e2135b0db	782	break;
Yann	0:f30e2135b0db	783	default:
Yann	0:f30e2135b0db	784	break;
Yann	0:f30e2135b0db	785	}
Yann	0:f30e2135b0db	786	return ERR_OK;
Yann	0:f30e2135b0db	787	}
Yann	0:f30e2135b0db	788
Yann	0:f30e2135b0db	789	#if TCP_QUEUE_OOSEQ
Yann	0:f30e2135b0db	790	/**
Yann	0:f30e2135b0db	791	* Insert segment into the list (segments covered with new one will be deleted)
Yann	0:f30e2135b0db	792	*
Yann	0:f30e2135b0db	793	* Called from tcp_receive()
Yann	0:f30e2135b0db	794	*/
Yann	0:f30e2135b0db	795	static void
Yann	0:f30e2135b0db	796	tcp_oos_insert_segment(struct tcp_seg cseg, struct tcp_seg next)
Yann	0:f30e2135b0db	797	{
Yann	0:f30e2135b0db	798	struct tcp_seg *old_seg;
Yann	0:f30e2135b0db	799
Yann	0:f30e2135b0db	800	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	801	/* received segment overlaps all following segments */
Yann	0:f30e2135b0db	802	tcp_segs_free(next);
Yann	0:f30e2135b0db	803	next = NULL;
Yann	0:f30e2135b0db	804	}
Yann	0:f30e2135b0db	805	else {
Yann	0:f30e2135b0db	806	/* delete some following segments
Yann	0:f30e2135b0db	807	oos queue may have segments with FIN flag */
Yann	0:f30e2135b0db	808	while (next &&
Yann	0:f30e2135b0db	809	TCP_SEQ_GEQ((seqno + cseg->len),
Yann	0:f30e2135b0db	810	(next->tcphdr->seqno + next->len))) {
Yann	0:f30e2135b0db	811	/* cseg with FIN already processed */
Yann	0:f30e2135b0db	812	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	813	TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
Yann	0:f30e2135b0db	814	}
Yann	0:f30e2135b0db	815	old_seg = next;
Yann	0:f30e2135b0db	816	next = next->next;
Yann	0:f30e2135b0db	817	tcp_seg_free(old_seg);
Yann	0:f30e2135b0db	818	}
Yann	0:f30e2135b0db	819	if (next &&
Yann	0:f30e2135b0db	820	TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
Yann	0:f30e2135b0db	821	/* We need to trim the incoming segment. */
Yann	0:f30e2135b0db	822	cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
Yann	0:f30e2135b0db	823	pbuf_realloc(cseg->p, cseg->len);
Yann	0:f30e2135b0db	824	}
Yann	0:f30e2135b0db	825	}
Yann	0:f30e2135b0db	826	cseg->next = next;
Yann	0:f30e2135b0db	827	}
Yann	0:f30e2135b0db	828	#endif /* TCP_QUEUE_OOSEQ */
Yann	0:f30e2135b0db	829
Yann	0:f30e2135b0db	830	/**
Yann	0:f30e2135b0db	831	* Called by tcp_process. Checks if the given segment is an ACK for outstanding
Yann	0:f30e2135b0db	832	* data, and if so frees the memory of the buffered data. Next, is places the
Yann	0:f30e2135b0db	833	* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
Yann	0:f30e2135b0db	834	* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
Yann	0:f30e2135b0db	835	* i it has been removed from the buffer.
Yann	0:f30e2135b0db	836	*
Yann	0:f30e2135b0db	837	* If the incoming segment constitutes an ACK for a segment that was used for RTT
Yann	0:f30e2135b0db	838	* estimation, the RTT is estimated here as well.
Yann	0:f30e2135b0db	839	*
Yann	0:f30e2135b0db	840	* Called from tcp_process().
Yann	0:f30e2135b0db	841	*/
Yann	0:f30e2135b0db	842	static void
Yann	0:f30e2135b0db	843	tcp_receive(struct tcp_pcb *pcb)
Yann	0:f30e2135b0db	844	{
Yann	0:f30e2135b0db	845	struct tcp_seg *next;
Yann	0:f30e2135b0db	846	#if TCP_QUEUE_OOSEQ
Yann	0:f30e2135b0db	847	struct tcp_seg prev, cseg;
Yann	0:f30e2135b0db	848	#endif /* TCP_QUEUE_OOSEQ */
Yann	0:f30e2135b0db	849	struct pbuf *p;
Yann	0:f30e2135b0db	850	s32_t off;
Yann	0:f30e2135b0db	851	s16_t m;
Yann	0:f30e2135b0db	852	u32_t right_wnd_edge;
Yann	0:f30e2135b0db	853	u16_t new_tot_len;
Yann	0:f30e2135b0db	854	int found_dupack = 0;
Yann	0:f30e2135b0db	855
Yann	0:f30e2135b0db	856	if (flags & TCP_ACK) {
Yann	0:f30e2135b0db	857	right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
Yann	0:f30e2135b0db	858
Yann	0:f30e2135b0db	859	/* Update window. */
Yann	0:f30e2135b0db	860	if (TCP_SEQ_LT(pcb->snd_wl1, seqno) \|\|
Yann	0:f30e2135b0db	861	(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) \|\|
Yann	0:f30e2135b0db	862	(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
Yann	0:f30e2135b0db	863	pcb->snd_wnd = tcphdr->wnd;
Yann	0:f30e2135b0db	864	pcb->snd_wl1 = seqno;
Yann	0:f30e2135b0db	865	pcb->snd_wl2 = ackno;
Yann	0:f30e2135b0db	866	if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
Yann	0:f30e2135b0db	867	pcb->persist_backoff = 0;
Yann	0:f30e2135b0db	868	}
Yann	0:f30e2135b0db	869	LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
Yann	0:f30e2135b0db	870	#if TCP_WND_DEBUG
Yann	0:f30e2135b0db	871	} else {
Yann	0:f30e2135b0db	872	if (pcb->snd_wnd != tcphdr->wnd) {
Yann	0:f30e2135b0db	873	LWIP_DEBUGF(TCP_WND_DEBUG,
Yann	0:f30e2135b0db	874	("tcp_receive: no window update lastack %"U32_F" ackno %"
Yann	0:f30e2135b0db	875	U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
Yann	0:f30e2135b0db	876	pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
Yann	0:f30e2135b0db	877	}
Yann	0:f30e2135b0db	878	#endif /* TCP_WND_DEBUG */
Yann	0:f30e2135b0db	879	}
Yann	0:f30e2135b0db	880
Yann	0:f30e2135b0db	881	/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
Yann	0:f30e2135b0db	882	* duplicate ack if:
Yann	0:f30e2135b0db	883	* 1) It doesn't ACK new data
Yann	0:f30e2135b0db	884	* 2) length of received packet is zero (i.e. no payload)
Yann	0:f30e2135b0db	885	* 3) the advertised window hasn't changed
Yann	0:f30e2135b0db	886	* 4) There is outstanding unacknowledged data (retransmission timer running)
Yann	0:f30e2135b0db	887	* 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
Yann	0:f30e2135b0db	888	*
Yann	0:f30e2135b0db	889	* If it passes all five, should process as a dupack:
Yann	0:f30e2135b0db	890	* a) dupacks < 3: do nothing
Yann	0:f30e2135b0db	891	* b) dupacks == 3: fast retransmit
Yann	0:f30e2135b0db	892	* c) dupacks > 3: increase cwnd
Yann	0:f30e2135b0db	893	*
Yann	0:f30e2135b0db	894	* If it only passes 1-3, should reset dupack counter (and add to
Yann	0:f30e2135b0db	895	* stats, which we don't do in lwIP)
Yann	0:f30e2135b0db	896	*
Yann	0:f30e2135b0db	897	* If it only passes 1, should reset dupack counter
Yann	0:f30e2135b0db	898	*
Yann	0:f30e2135b0db	899	*/
Yann	0:f30e2135b0db	900
Yann	0:f30e2135b0db	901	/* Clause 1 */
Yann	0:f30e2135b0db	902	if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
Yann	0:f30e2135b0db	903	pcb->acked = 0;
Yann	0:f30e2135b0db	904	/* Clause 2 */
Yann	0:f30e2135b0db	905	if (tcplen == 0) {
Yann	0:f30e2135b0db	906	/* Clause 3 */
Yann	0:f30e2135b0db	907	if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
Yann	0:f30e2135b0db	908	/* Clause 4 */
Yann	0:f30e2135b0db	909	if (pcb->rtime >= 0) {
Yann	0:f30e2135b0db	910	/* Clause 5 */
Yann	0:f30e2135b0db	911	if (pcb->lastack == ackno) {
Yann	0:f30e2135b0db	912	found_dupack = 1;
Yann	0:f30e2135b0db	913	if (pcb->dupacks + 1 > pcb->dupacks)
Yann	0:f30e2135b0db	914	++pcb->dupacks;
Yann	0:f30e2135b0db	915	if (pcb->dupacks > 3) {
Yann	0:f30e2135b0db	916	/* Inflate the congestion window, but not if it means that
Yann	0:f30e2135b0db	917	the value overflows. */
Yann	0:f30e2135b0db	918	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
Yann	0:f30e2135b0db	919	pcb->cwnd += pcb->mss;
Yann	0:f30e2135b0db	920	}
Yann	0:f30e2135b0db	921	} else if (pcb->dupacks == 3) {
Yann	0:f30e2135b0db	922	/* Do fast retransmit */
Yann	0:f30e2135b0db	923	tcp_rexmit_fast(pcb);
Yann	0:f30e2135b0db	924	}
Yann	0:f30e2135b0db	925	}
Yann	0:f30e2135b0db	926	}
Yann	0:f30e2135b0db	927	}
Yann	0:f30e2135b0db	928	}
Yann	0:f30e2135b0db	929	/* If Clause (1) or more is true, but not a duplicate ack, reset
Yann	0:f30e2135b0db	930	* count of consecutive duplicate acks */
Yann	0:f30e2135b0db	931	if (!found_dupack) {
Yann	0:f30e2135b0db	932	pcb->dupacks = 0;
Yann	0:f30e2135b0db	933	}
Yann	0:f30e2135b0db	934	} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
Yann	0:f30e2135b0db	935	/* We come here when the ACK acknowledges new data. */
Yann	0:f30e2135b0db	936
Yann	0:f30e2135b0db	937	/* Reset the "IN Fast Retransmit" flag, since we are no longer
Yann	0:f30e2135b0db	938	in fast retransmit. Also reset the congestion window to the
Yann	0:f30e2135b0db	939	slow start threshold. */
Yann	0:f30e2135b0db	940	if (pcb->flags & TF_INFR) {
Yann	0:f30e2135b0db	941	pcb->flags &= ~TF_INFR;
Yann	0:f30e2135b0db	942	pcb->cwnd = pcb->ssthresh;
Yann	0:f30e2135b0db	943	}
Yann	0:f30e2135b0db	944
Yann	0:f30e2135b0db	945	/* Reset the number of retransmissions. */
Yann	0:f30e2135b0db	946	pcb->nrtx = 0;
Yann	0:f30e2135b0db	947
Yann	0:f30e2135b0db	948	/* Reset the retransmission time-out. */
Yann	0:f30e2135b0db	949	pcb->rto = (pcb->sa >> 3) + pcb->sv;
Yann	0:f30e2135b0db	950
Yann	0:f30e2135b0db	951	/* Update the send buffer space. Diff between the two can never exceed 64K? */
Yann	0:f30e2135b0db	952	pcb->acked = (u16_t)(ackno - pcb->lastack);
Yann	0:f30e2135b0db	953
Yann	0:f30e2135b0db	954	pcb->snd_buf += pcb->acked;
Yann	0:f30e2135b0db	955
Yann	0:f30e2135b0db	956	/* Reset the fast retransmit variables. */
Yann	0:f30e2135b0db	957	pcb->dupacks = 0;
Yann	0:f30e2135b0db	958	pcb->lastack = ackno;
Yann	0:f30e2135b0db	959
Yann	0:f30e2135b0db	960	/* Update the congestion control variables (cwnd and
Yann	0:f30e2135b0db	961	ssthresh). */
Yann	0:f30e2135b0db	962	if (pcb->state >= ESTABLISHED) {
Yann	0:f30e2135b0db	963	if (pcb->cwnd < pcb->ssthresh) {
Yann	0:f30e2135b0db	964	if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
Yann	0:f30e2135b0db	965	pcb->cwnd += pcb->mss;
Yann	0:f30e2135b0db	966	}
Yann	0:f30e2135b0db	967	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
Yann	0:f30e2135b0db	968	} else {
Yann	0:f30e2135b0db	969	u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
Yann	0:f30e2135b0db	970	if (new_cwnd > pcb->cwnd) {
Yann	0:f30e2135b0db	971	pcb->cwnd = new_cwnd;
Yann	0:f30e2135b0db	972	}
Yann	0:f30e2135b0db	973	LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
Yann	0:f30e2135b0db	974	}
Yann	0:f30e2135b0db	975	}
Yann	0:f30e2135b0db	976	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
Yann	0:f30e2135b0db	977	ackno,
Yann	0:f30e2135b0db	978	pcb->unacked != NULL?
Yann	0:f30e2135b0db	979	ntohl(pcb->unacked->tcphdr->seqno): 0,
Yann	0:f30e2135b0db	980	pcb->unacked != NULL?
Yann	0:f30e2135b0db	981	ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
Yann	0:f30e2135b0db	982
Yann	0:f30e2135b0db	983	/* Remove segment from the unacknowledged list if the incoming
Yann	0:f30e2135b0db	984	ACK acknowlegdes them. */
Yann	0:f30e2135b0db	985	while (pcb->unacked != NULL &&
Yann	0:f30e2135b0db	986	TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
Yann	0:f30e2135b0db	987	TCP_TCPLEN(pcb->unacked), ackno)) {
Yann	0:f30e2135b0db	988	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
Yann	0:f30e2135b0db	989	ntohl(pcb->unacked->tcphdr->seqno),
Yann	0:f30e2135b0db	990	ntohl(pcb->unacked->tcphdr->seqno) +
Yann	0:f30e2135b0db	991	TCP_TCPLEN(pcb->unacked)));
Yann	0:f30e2135b0db	992
Yann	0:f30e2135b0db	993	next = pcb->unacked;
Yann	0:f30e2135b0db	994	pcb->unacked = pcb->unacked->next;
Yann	0:f30e2135b0db	995
Yann	0:f30e2135b0db	996	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
Yann	0:f30e2135b0db	997	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
Yann	0:f30e2135b0db	998	/* Prevent ACK for FIN to generate a sent event */
Yann	0:f30e2135b0db	999	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
Yann	0:f30e2135b0db	1000	pcb->acked--;
Yann	0:f30e2135b0db	1001	}
Yann	0:f30e2135b0db	1002
Yann	0:f30e2135b0db	1003	pcb->snd_queuelen -= pbuf_clen(next->p);
Yann	0:f30e2135b0db	1004	tcp_seg_free(next);
Yann	0:f30e2135b0db	1005
Yann	0:f30e2135b0db	1006	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
Yann	0:f30e2135b0db	1007	if (pcb->snd_queuelen != 0) {
Yann	0:f30e2135b0db	1008	LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL \|\|
Yann	0:f30e2135b0db	1009	pcb->unsent != NULL);
Yann	0:f30e2135b0db	1010	}
Yann	0:f30e2135b0db	1011	}
Yann	0:f30e2135b0db	1012
Yann	0:f30e2135b0db	1013	/* If there's nothing left to acknowledge, stop the retransmit
Yann	0:f30e2135b0db	1014	timer, otherwise reset it to start again */
Yann	0:f30e2135b0db	1015	if(pcb->unacked == NULL)
Yann	0:f30e2135b0db	1016	pcb->rtime = -1;
Yann	0:f30e2135b0db	1017	else
Yann	0:f30e2135b0db	1018	pcb->rtime = 0;
Yann	0:f30e2135b0db	1019
Yann	0:f30e2135b0db	1020	pcb->polltmr = 0;
Yann	0:f30e2135b0db	1021	} else {
Yann	0:f30e2135b0db	1022	/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
Yann	0:f30e2135b0db	1023	pcb->acked = 0;
Yann	0:f30e2135b0db	1024	}
Yann	0:f30e2135b0db	1025
Yann	0:f30e2135b0db	1026	/* We go through the ->unsent list to see if any of the segments
Yann	0:f30e2135b0db	1027	on the list are acknowledged by the ACK. This may seem
Yann	0:f30e2135b0db	1028	strange since an "unsent" segment shouldn't be acked. The
Yann	0:f30e2135b0db	1029	rationale is that lwIP puts all outstanding segments on the
Yann	0:f30e2135b0db	1030	->unsent list after a retransmission, so these segments may
Yann	0:f30e2135b0db	1031	in fact have been sent once. */
Yann	0:f30e2135b0db	1032	while (pcb->unsent != NULL &&
Yann	0:f30e2135b0db	1033	TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
Yann	0:f30e2135b0db	1034	TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
Yann	0:f30e2135b0db	1035	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
Yann	0:f30e2135b0db	1036	ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
Yann	0:f30e2135b0db	1037	TCP_TCPLEN(pcb->unsent)));
Yann	0:f30e2135b0db	1038
Yann	0:f30e2135b0db	1039	next = pcb->unsent;
Yann	0:f30e2135b0db	1040	pcb->unsent = pcb->unsent->next;
Yann	0:f30e2135b0db	1041	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
Yann	0:f30e2135b0db	1042	LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
Yann	0:f30e2135b0db	1043	/* Prevent ACK for FIN to generate a sent event */
Yann	0:f30e2135b0db	1044	if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
Yann	0:f30e2135b0db	1045	pcb->acked--;
Yann	0:f30e2135b0db	1046	}
Yann	0:f30e2135b0db	1047	pcb->snd_queuelen -= pbuf_clen(next->p);
Yann	0:f30e2135b0db	1048	tcp_seg_free(next);
Yann	0:f30e2135b0db	1049	LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
Yann	0:f30e2135b0db	1050	if (pcb->snd_queuelen != 0) {
Yann	0:f30e2135b0db	1051	LWIP_ASSERT("tcp_receive: valid queue length",
Yann	0:f30e2135b0db	1052	pcb->unacked != NULL \|\| pcb->unsent != NULL);
Yann	0:f30e2135b0db	1053	}
Yann	0:f30e2135b0db	1054	}
Yann	0:f30e2135b0db	1055	/* End of ACK for new data processing. */
Yann	0:f30e2135b0db	1056
Yann	0:f30e2135b0db	1057	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
Yann	0:f30e2135b0db	1058	pcb->rttest, pcb->rtseq, ackno));
Yann	0:f30e2135b0db	1059
Yann	0:f30e2135b0db	1060	/* RTT estimation calculations. This is done by checking if the
Yann	0:f30e2135b0db	1061	incoming segment acknowledges the segment we use to take a
Yann	0:f30e2135b0db	1062	round-trip time measurement. */
Yann	0:f30e2135b0db	1063	if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
Yann	0:f30e2135b0db	1064	/* diff between this shouldn't exceed 32K since this are tcp timer ticks
Yann	0:f30e2135b0db	1065	and a round-trip shouldn't be that long... */
Yann	0:f30e2135b0db	1066	m = (s16_t)(tcp_ticks - pcb->rttest);
Yann	0:f30e2135b0db	1067
Yann	0:f30e2135b0db	1068	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
Yann	0:f30e2135b0db	1069	m, m * TCP_SLOW_INTERVAL));
Yann	0:f30e2135b0db	1070
Yann	0:f30e2135b0db	1071	/* This is taken directly from VJs original code in his paper */
Yann	0:f30e2135b0db	1072	m = m - (pcb->sa >> 3);
Yann	0:f30e2135b0db	1073	pcb->sa += m;
Yann	0:f30e2135b0db	1074	if (m < 0) {
Yann	0:f30e2135b0db	1075	m = -m;
Yann	0:f30e2135b0db	1076	}
Yann	0:f30e2135b0db	1077	m = m - (pcb->sv >> 2);
Yann	0:f30e2135b0db	1078	pcb->sv += m;
Yann	0:f30e2135b0db	1079	pcb->rto = (pcb->sa >> 3) + pcb->sv;
Yann	0:f30e2135b0db	1080
Yann	0:f30e2135b0db	1081	LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
Yann	0:f30e2135b0db	1082	pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
Yann	0:f30e2135b0db	1083
Yann	0:f30e2135b0db	1084	pcb->rttest = 0;
Yann	0:f30e2135b0db	1085	}
Yann	0:f30e2135b0db	1086	}
Yann	0:f30e2135b0db	1087
Yann	0:f30e2135b0db	1088	/* If the incoming segment contains data, we must process it
Yann	0:f30e2135b0db	1089	further. */
Yann	0:f30e2135b0db	1090	if (tcplen > 0) {
Yann	0:f30e2135b0db	1091	/* This code basically does three things:
Yann	0:f30e2135b0db	1092
Yann	0:f30e2135b0db	1093	+) If the incoming segment contains data that is the next
Yann	0:f30e2135b0db	1094	in-sequence data, this data is passed to the application. This
Yann	0:f30e2135b0db	1095	might involve trimming the first edge of the data. The rcv_nxt
Yann	0:f30e2135b0db	1096	variable and the advertised window are adjusted.
Yann	0:f30e2135b0db	1097
Yann	0:f30e2135b0db	1098	+) If the incoming segment has data that is above the next
Yann	0:f30e2135b0db	1099	sequence number expected (->rcv_nxt), the segment is placed on
Yann	0:f30e2135b0db	1100	the ->ooseq queue. This is done by finding the appropriate
Yann	0:f30e2135b0db	1101	place in the ->ooseq queue (which is ordered by sequence
Yann	0:f30e2135b0db	1102	number) and trim the segment in both ends if needed. An
Yann	0:f30e2135b0db	1103	immediate ACK is sent to indicate that we received an
Yann	0:f30e2135b0db	1104	out-of-sequence segment.
Yann	0:f30e2135b0db	1105
Yann	0:f30e2135b0db	1106	+) Finally, we check if the first segment on the ->ooseq queue
Yann	0:f30e2135b0db	1107	now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
Yann	0:f30e2135b0db	1108	rcv_nxt > ooseq->seqno, we must trim the first edge of the
Yann	0:f30e2135b0db	1109	segment on ->ooseq before we adjust rcv_nxt. The data in the
Yann	0:f30e2135b0db	1110	segments that are now on sequence are chained onto the
Yann	0:f30e2135b0db	1111	incoming segment so that we only need to call the application
Yann	0:f30e2135b0db	1112	once.
Yann	0:f30e2135b0db	1113	*/
Yann	0:f30e2135b0db	1114
Yann	0:f30e2135b0db	1115	/* First, we check if we must trim the first edge. We have to do
Yann	0:f30e2135b0db	1116	this if the sequence number of the incoming segment is less
Yann	0:f30e2135b0db	1117	than rcv_nxt, and the sequence number plus the length of the
Yann	0:f30e2135b0db	1118	segment is larger than rcv_nxt. */
Yann	0:f30e2135b0db	1119	/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
Yann	0:f30e2135b0db	1120	if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
Yann	0:f30e2135b0db	1121	if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
Yann	0:f30e2135b0db	1122	/* Trimming the first edge is done by pushing the payload
Yann	0:f30e2135b0db	1123	pointer in the pbuf downwards. This is somewhat tricky since
Yann	0:f30e2135b0db	1124	we do not want to discard the full contents of the pbuf up to
Yann	0:f30e2135b0db	1125	the new starting point of the data since we have to keep the
Yann	0:f30e2135b0db	1126	TCP header which is present in the first pbuf in the chain.
Yann	0:f30e2135b0db	1127
Yann	0:f30e2135b0db	1128	What is done is really quite a nasty hack: the first pbuf in
Yann	0:f30e2135b0db	1129	the pbuf chain is pointed to by inseg.p. Since we need to be
Yann	0:f30e2135b0db	1130	able to deallocate the whole pbuf, we cannot change this
Yann	0:f30e2135b0db	1131	inseg.p pointer to point to any of the later pbufs in the
Yann	0:f30e2135b0db	1132	chain. Instead, we point the ->payload pointer in the first
Yann	0:f30e2135b0db	1133	pbuf to data in one of the later pbufs. We also set the
Yann	0:f30e2135b0db	1134	inseg.data pointer to point to the right place. This way, the
Yann	0:f30e2135b0db	1135	->p pointer will still point to the first pbuf, but the
Yann	0:f30e2135b0db	1136	->p->payload pointer will point to data in another pbuf.
Yann	0:f30e2135b0db	1137
Yann	0:f30e2135b0db	1138	After we are done with adjusting the pbuf pointers we must
Yann	0:f30e2135b0db	1139	adjust the ->data pointer in the seg and the segment
Yann	0:f30e2135b0db	1140	length.*/
Yann	0:f30e2135b0db	1141
Yann	0:f30e2135b0db	1142	off = pcb->rcv_nxt - seqno;
Yann	0:f30e2135b0db	1143	p = inseg.p;
Yann	0:f30e2135b0db	1144	LWIP_ASSERT("inseg.p != NULL", inseg.p);
Yann	0:f30e2135b0db	1145	LWIP_ASSERT("insane offset!", (off < 0x7fff));
Yann	0:f30e2135b0db	1146	if (inseg.p->len < off) {
Yann	0:f30e2135b0db	1147	LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
Yann	0:f30e2135b0db	1148	new_tot_len = (u16_t)(inseg.p->tot_len - off);
Yann	0:f30e2135b0db	1149	while (p->len < off) {
Yann	0:f30e2135b0db	1150	off -= p->len;
Yann	0:f30e2135b0db	1151	/* KJM following line changed (with addition of new_tot_len var)
Yann	0:f30e2135b0db	1152	to fix bug #9076
Yann	0:f30e2135b0db	1153	inseg.p->tot_len -= p->len; */
Yann	0:f30e2135b0db	1154	p->tot_len = new_tot_len;
Yann	0:f30e2135b0db	1155	p->len = 0;
Yann	0:f30e2135b0db	1156	p = p->next;
Yann	0:f30e2135b0db	1157	}
Yann	0:f30e2135b0db	1158	if(pbuf_header(p, (s16_t)-off)) {
Yann	0:f30e2135b0db	1159	/* Do we need to cope with this failing? Assert for now */
Yann	0:f30e2135b0db	1160	LWIP_ASSERT("pbuf_header failed", 0);
Yann	0:f30e2135b0db	1161	}
Yann	0:f30e2135b0db	1162	} else {
Yann	0:f30e2135b0db	1163	if(pbuf_header(inseg.p, (s16_t)-off)) {
Yann	0:f30e2135b0db	1164	/* Do we need to cope with this failing? Assert for now */
Yann	0:f30e2135b0db	1165	LWIP_ASSERT("pbuf_header failed", 0);
Yann	0:f30e2135b0db	1166	}
Yann	0:f30e2135b0db	1167	}
Yann	0:f30e2135b0db	1168	/* KJM following line changed to use p->payload rather than inseg->p->payload
Yann	0:f30e2135b0db	1169	to fix bug #9076 */
Yann	0:f30e2135b0db	1170	inseg.dataptr = p->payload;
Yann	0:f30e2135b0db	1171	inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
Yann	0:f30e2135b0db	1172	inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
Yann	0:f30e2135b0db	1173	}
Yann	0:f30e2135b0db	1174	else {
Yann	0:f30e2135b0db	1175	if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
Yann	0:f30e2135b0db	1176	/* the whole segment is < rcv_nxt */
Yann	0:f30e2135b0db	1177	/* must be a duplicate of a packet that has already been correctly handled */
Yann	0:f30e2135b0db	1178
Yann	0:f30e2135b0db	1179	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
Yann	0:f30e2135b0db	1180	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	1181	}
Yann	0:f30e2135b0db	1182	}
Yann	0:f30e2135b0db	1183
Yann	0:f30e2135b0db	1184	/* The sequence number must be within the window (above rcv_nxt
Yann	0:f30e2135b0db	1185	and below rcv_nxt + rcv_wnd) in order to be further
Yann	0:f30e2135b0db	1186	processed. */
Yann	0:f30e2135b0db	1187	if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
Yann	0:f30e2135b0db	1188	pcb->rcv_nxt + pcb->rcv_wnd - 1)){
Yann	0:f30e2135b0db	1189	if (pcb->rcv_nxt == seqno) {
Yann	0:f30e2135b0db	1190	/* The incoming segment is the next in sequence. We check if
Yann	0:f30e2135b0db	1191	we have to trim the end of the segment and update rcv_nxt
Yann	0:f30e2135b0db	1192	and pass the data to the application. */
Yann	0:f30e2135b0db	1193	tcplen = TCP_TCPLEN(&inseg);
Yann	0:f30e2135b0db	1194
Yann	0:f30e2135b0db	1195	if (tcplen > pcb->rcv_wnd) {
Yann	0:f30e2135b0db	1196	LWIP_DEBUGF(TCP_INPUT_DEBUG,
Yann	0:f30e2135b0db	1197	("tcp_receive: other end overran receive window"
Yann	0:f30e2135b0db	1198	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
Yann	0:f30e2135b0db	1199	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
Yann	0:f30e2135b0db	1200	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1201	/* Must remove the FIN from the header as we're trimming
Yann	0:f30e2135b0db	1202	* that byte of sequence-space from the packet */
Yann	0:f30e2135b0db	1203	TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
Yann	0:f30e2135b0db	1204	}
Yann	0:f30e2135b0db	1205	/* Adjust length of segment to fit in the window. */
Yann	0:f30e2135b0db	1206	inseg.len = pcb->rcv_wnd;
Yann	0:f30e2135b0db	1207	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
Yann	0:f30e2135b0db	1208	inseg.len -= 1;
Yann	0:f30e2135b0db	1209	}
Yann	0:f30e2135b0db	1210	pbuf_realloc(inseg.p, inseg.len);
Yann	0:f30e2135b0db	1211	tcplen = TCP_TCPLEN(&inseg);
Yann	0:f30e2135b0db	1212	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
Yann	0:f30e2135b0db	1213	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
Yann	0:f30e2135b0db	1214	}
Yann	0:f30e2135b0db	1215	#if TCP_QUEUE_OOSEQ
Yann	0:f30e2135b0db	1216	/* Received in-sequence data, adjust ooseq data if:
Yann	0:f30e2135b0db	1217	- FIN has been received or
Yann	0:f30e2135b0db	1218	- inseq overlaps with ooseq */
Yann	0:f30e2135b0db	1219	if (pcb->ooseq != NULL) {
Yann	0:f30e2135b0db	1220	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1221	LWIP_DEBUGF(TCP_INPUT_DEBUG,
Yann	0:f30e2135b0db	1222	("tcp_receive: received in-order FIN, binning ooseq queue\n"));
Yann	0:f30e2135b0db	1223	/* Received in-order FIN means anything that was received
Yann	0:f30e2135b0db	1224	* out of order must now have been received in-order, so
Yann	0:f30e2135b0db	1225	* bin the ooseq queue */
Yann	0:f30e2135b0db	1226	while (pcb->ooseq != NULL) {
Yann	0:f30e2135b0db	1227	struct tcp_seg *old_ooseq = pcb->ooseq;
Yann	0:f30e2135b0db	1228	pcb->ooseq = pcb->ooseq->next;
Yann	0:f30e2135b0db	1229	tcp_seg_free(old_ooseq);
Yann	0:f30e2135b0db	1230	}
Yann	0:f30e2135b0db	1231	}
Yann	0:f30e2135b0db	1232	else {
Yann	0:f30e2135b0db	1233	next = pcb->ooseq;
Yann	0:f30e2135b0db	1234	/* Remove all segments on ooseq that are covered by inseg already.
Yann	0:f30e2135b0db	1235	* FIN is copied from ooseq to inseg if present. */
Yann	0:f30e2135b0db	1236	while (next &&
Yann	0:f30e2135b0db	1237	TCP_SEQ_GEQ(seqno + tcplen,
Yann	0:f30e2135b0db	1238	next->tcphdr->seqno + next->len)) {
Yann	0:f30e2135b0db	1239	/* inseg cannot have FIN here (already processed above) */
Yann	0:f30e2135b0db	1240	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
Yann	0:f30e2135b0db	1241	(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
Yann	0:f30e2135b0db	1242	TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
Yann	0:f30e2135b0db	1243	tcplen = TCP_TCPLEN(&inseg);
Yann	0:f30e2135b0db	1244	}
Yann	0:f30e2135b0db	1245	prev = next;
Yann	0:f30e2135b0db	1246	next = next->next;
Yann	0:f30e2135b0db	1247	tcp_seg_free(prev);
Yann	0:f30e2135b0db	1248	}
Yann	0:f30e2135b0db	1249	/* Now trim right side of inseg if it overlaps with the first
Yann	0:f30e2135b0db	1250	* segment on ooseq */
Yann	0:f30e2135b0db	1251	if (next &&
Yann	0:f30e2135b0db	1252	TCP_SEQ_GT(seqno + tcplen,
Yann	0:f30e2135b0db	1253	next->tcphdr->seqno)) {
Yann	0:f30e2135b0db	1254	/* inseg cannot have FIN here (already processed above) */
Yann	0:f30e2135b0db	1255	inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
Yann	0:f30e2135b0db	1256	if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
Yann	0:f30e2135b0db	1257	inseg.len -= 1;
Yann	0:f30e2135b0db	1258	}
Yann	0:f30e2135b0db	1259	pbuf_realloc(inseg.p, inseg.len);
Yann	0:f30e2135b0db	1260	tcplen = TCP_TCPLEN(&inseg);
Yann	0:f30e2135b0db	1261	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
Yann	0:f30e2135b0db	1262	(seqno + tcplen) == next->tcphdr->seqno);
Yann	0:f30e2135b0db	1263	}
Yann	0:f30e2135b0db	1264	pcb->ooseq = next;
Yann	0:f30e2135b0db	1265	}
Yann	0:f30e2135b0db	1266	}
Yann	0:f30e2135b0db	1267	#endif /* TCP_QUEUE_OOSEQ */
Yann	0:f30e2135b0db	1268
Yann	0:f30e2135b0db	1269	pcb->rcv_nxt = seqno + tcplen;
Yann	0:f30e2135b0db	1270
Yann	0:f30e2135b0db	1271	/* Update the receiver's (our) window. */
Yann	0:f30e2135b0db	1272	LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
Yann	0:f30e2135b0db	1273	pcb->rcv_wnd -= tcplen;
Yann	0:f30e2135b0db	1274
Yann	0:f30e2135b0db	1275	tcp_update_rcv_ann_wnd(pcb);
Yann	0:f30e2135b0db	1276
Yann	0:f30e2135b0db	1277	/* If there is data in the segment, we make preparations to
Yann	0:f30e2135b0db	1278	pass this up to the application. The ->recv_data variable
Yann	0:f30e2135b0db	1279	is used for holding the pbuf that goes to the
Yann	0:f30e2135b0db	1280	application. The code for reassembling out-of-sequence data
Yann	0:f30e2135b0db	1281	chains its data on this pbuf as well.
Yann	0:f30e2135b0db	1282
Yann	0:f30e2135b0db	1283	If the segment was a FIN, we set the TF_GOT_FIN flag that will
Yann	0:f30e2135b0db	1284	be used to indicate to the application that the remote side has
Yann	0:f30e2135b0db	1285	closed its end of the connection. */
Yann	0:f30e2135b0db	1286	if (inseg.p->tot_len > 0) {
Yann	0:f30e2135b0db	1287	recv_data = inseg.p;
Yann	0:f30e2135b0db	1288	/* Since this pbuf now is the responsibility of the
Yann	0:f30e2135b0db	1289	application, we delete our reference to it so that we won't
Yann	0:f30e2135b0db	1290	(mistakingly) deallocate it. */
Yann	0:f30e2135b0db	1291	inseg.p = NULL;
Yann	0:f30e2135b0db	1292	}
Yann	0:f30e2135b0db	1293	if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1294	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
Yann	0:f30e2135b0db	1295	recv_flags \|= TF_GOT_FIN;
Yann	0:f30e2135b0db	1296	}
Yann	0:f30e2135b0db	1297
Yann	0:f30e2135b0db	1298	#if TCP_QUEUE_OOSEQ
Yann	0:f30e2135b0db	1299	/* We now check if we have segments on the ->ooseq queue that
Yann	0:f30e2135b0db	1300	are now in sequence. */
Yann	0:f30e2135b0db	1301	while (pcb->ooseq != NULL &&
Yann	0:f30e2135b0db	1302	pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
Yann	0:f30e2135b0db	1303
Yann	0:f30e2135b0db	1304	cseg = pcb->ooseq;
Yann	0:f30e2135b0db	1305	seqno = pcb->ooseq->tcphdr->seqno;
Yann	0:f30e2135b0db	1306
Yann	0:f30e2135b0db	1307	pcb->rcv_nxt += TCP_TCPLEN(cseg);
Yann	0:f30e2135b0db	1308	LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
Yann	0:f30e2135b0db	1309	pcb->rcv_wnd >= TCP_TCPLEN(cseg));
Yann	0:f30e2135b0db	1310	pcb->rcv_wnd -= TCP_TCPLEN(cseg);
Yann	0:f30e2135b0db	1311
Yann	0:f30e2135b0db	1312	tcp_update_rcv_ann_wnd(pcb);
Yann	0:f30e2135b0db	1313
Yann	0:f30e2135b0db	1314	if (cseg->p->tot_len > 0) {
Yann	0:f30e2135b0db	1315	/* Chain this pbuf onto the pbuf that we will pass to
Yann	0:f30e2135b0db	1316	the application. */
Yann	0:f30e2135b0db	1317	if (recv_data) {
Yann	0:f30e2135b0db	1318	pbuf_cat(recv_data, cseg->p);
Yann	0:f30e2135b0db	1319	} else {
Yann	0:f30e2135b0db	1320	recv_data = cseg->p;
Yann	0:f30e2135b0db	1321	}
Yann	0:f30e2135b0db	1322	cseg->p = NULL;
Yann	0:f30e2135b0db	1323	}
Yann	0:f30e2135b0db	1324	if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1325	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
Yann	0:f30e2135b0db	1326	recv_flags \|= TF_GOT_FIN;
Yann	0:f30e2135b0db	1327	if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
Yann	0:f30e2135b0db	1328	pcb->state = CLOSE_WAIT;
Yann	0:f30e2135b0db	1329	}
Yann	0:f30e2135b0db	1330	}
Yann	0:f30e2135b0db	1331
Yann	0:f30e2135b0db	1332	pcb->ooseq = cseg->next;
Yann	0:f30e2135b0db	1333	tcp_seg_free(cseg);
Yann	0:f30e2135b0db	1334	}
Yann	0:f30e2135b0db	1335	#endif /* TCP_QUEUE_OOSEQ */
Yann	0:f30e2135b0db	1336
Yann	0:f30e2135b0db	1337
Yann	0:f30e2135b0db	1338	/* Acknowledge the segment(s). */
Yann	0:f30e2135b0db	1339	tcp_ack(pcb);
Yann	0:f30e2135b0db	1340
Yann	0:f30e2135b0db	1341	} else {
Yann	0:f30e2135b0db	1342	/* We get here if the incoming segment is out-of-sequence. */
Yann	0:f30e2135b0db	1343	tcp_send_empty_ack(pcb);
Yann	0:f30e2135b0db	1344	#if TCP_QUEUE_OOSEQ
Yann	0:f30e2135b0db	1345	/* We queue the segment on the ->ooseq queue. */
Yann	0:f30e2135b0db	1346	if (pcb->ooseq == NULL) {
Yann	0:f30e2135b0db	1347	pcb->ooseq = tcp_seg_copy(&inseg);
Yann	0:f30e2135b0db	1348	} else {
Yann	0:f30e2135b0db	1349	/* If the queue is not empty, we walk through the queue and
Yann	0:f30e2135b0db	1350	try to find a place where the sequence number of the
Yann	0:f30e2135b0db	1351	incoming segment is between the sequence numbers of the
Yann	0:f30e2135b0db	1352	previous and the next segment on the ->ooseq queue. That is
Yann	0:f30e2135b0db	1353	the place where we put the incoming segment. If needed, we
Yann	0:f30e2135b0db	1354	trim the second edges of the previous and the incoming
Yann	0:f30e2135b0db	1355	segment so that it will fit into the sequence.
Yann	0:f30e2135b0db	1356
Yann	0:f30e2135b0db	1357	If the incoming segment has the same sequence number as a
Yann	0:f30e2135b0db	1358	segment on the ->ooseq queue, we discard the segment that
Yann	0:f30e2135b0db	1359	contains less data. */
Yann	0:f30e2135b0db	1360
Yann	0:f30e2135b0db	1361	prev = NULL;
Yann	0:f30e2135b0db	1362	for(next = pcb->ooseq; next != NULL; next = next->next) {
Yann	0:f30e2135b0db	1363	if (seqno == next->tcphdr->seqno) {
Yann	0:f30e2135b0db	1364	/* The sequence number of the incoming segment is the
Yann	0:f30e2135b0db	1365	same as the sequence number of the segment on
Yann	0:f30e2135b0db	1366	->ooseq. We check the lengths to see which one to
Yann	0:f30e2135b0db	1367	discard. */
Yann	0:f30e2135b0db	1368	if (inseg.len > next->len) {
Yann	0:f30e2135b0db	1369	/* The incoming segment is larger than the old
Yann	0:f30e2135b0db	1370	segment. We replace some segments with the new
Yann	0:f30e2135b0db	1371	one. */
Yann	0:f30e2135b0db	1372	cseg = tcp_seg_copy(&inseg);
Yann	0:f30e2135b0db	1373	if (cseg != NULL) {
Yann	0:f30e2135b0db	1374	if (prev != NULL) {
Yann	0:f30e2135b0db	1375	prev->next = cseg;
Yann	0:f30e2135b0db	1376	} else {
Yann	0:f30e2135b0db	1377	pcb->ooseq = cseg;
Yann	0:f30e2135b0db	1378	}
Yann	0:f30e2135b0db	1379	tcp_oos_insert_segment(cseg, next);
Yann	0:f30e2135b0db	1380	}
Yann	0:f30e2135b0db	1381	break;
Yann	0:f30e2135b0db	1382	} else {
Yann	0:f30e2135b0db	1383	/* Either the lenghts are the same or the incoming
Yann	0:f30e2135b0db	1384	segment was smaller than the old one; in either
Yann	0:f30e2135b0db	1385	case, we ditch the incoming segment. */
Yann	0:f30e2135b0db	1386	break;
Yann	0:f30e2135b0db	1387	}
Yann	0:f30e2135b0db	1388	} else {
Yann	0:f30e2135b0db	1389	if (prev == NULL) {
Yann	0:f30e2135b0db	1390	if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
Yann	0:f30e2135b0db	1391	/* The sequence number of the incoming segment is lower
Yann	0:f30e2135b0db	1392	than the sequence number of the first segment on the
Yann	0:f30e2135b0db	1393	queue. We put the incoming segment first on the
Yann	0:f30e2135b0db	1394	queue. */
Yann	0:f30e2135b0db	1395	cseg = tcp_seg_copy(&inseg);
Yann	0:f30e2135b0db	1396	if (cseg != NULL) {
Yann	0:f30e2135b0db	1397	pcb->ooseq = cseg;
Yann	0:f30e2135b0db	1398	tcp_oos_insert_segment(cseg, next);
Yann	0:f30e2135b0db	1399	}
Yann	0:f30e2135b0db	1400	break;
Yann	0:f30e2135b0db	1401	}
Yann	0:f30e2135b0db	1402	} else {
Yann	0:f30e2135b0db	1403	/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
Yann	0:f30e2135b0db	1404	TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
Yann	0:f30e2135b0db	1405	if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
Yann	0:f30e2135b0db	1406	/* The sequence number of the incoming segment is in
Yann	0:f30e2135b0db	1407	between the sequence numbers of the previous and
Yann	0:f30e2135b0db	1408	the next segment on ->ooseq. We trim trim the previous
Yann	0:f30e2135b0db	1409	segment, delete next segments that included in received segment
Yann	0:f30e2135b0db	1410	and trim received, if needed. */
Yann	0:f30e2135b0db	1411	cseg = tcp_seg_copy(&inseg);
Yann	0:f30e2135b0db	1412	if (cseg != NULL) {
Yann	0:f30e2135b0db	1413	if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
Yann	0:f30e2135b0db	1414	/* We need to trim the prev segment. */
Yann	0:f30e2135b0db	1415	prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
Yann	0:f30e2135b0db	1416	pbuf_realloc(prev->p, prev->len);
Yann	0:f30e2135b0db	1417	}
Yann	0:f30e2135b0db	1418	prev->next = cseg;
Yann	0:f30e2135b0db	1419	tcp_oos_insert_segment(cseg, next);
Yann	0:f30e2135b0db	1420	}
Yann	0:f30e2135b0db	1421	break;
Yann	0:f30e2135b0db	1422	}
Yann	0:f30e2135b0db	1423	}
Yann	0:f30e2135b0db	1424	/* If the "next" segment is the last segment on the
Yann	0:f30e2135b0db	1425	ooseq queue, we add the incoming segment to the end
Yann	0:f30e2135b0db	1426	of the list. */
Yann	0:f30e2135b0db	1427	if (next->next == NULL &&
Yann	0:f30e2135b0db	1428	TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
Yann	0:f30e2135b0db	1429	if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1430	/* segment "next" already contains all data */
Yann	0:f30e2135b0db	1431	break;
Yann	0:f30e2135b0db	1432	}
Yann	0:f30e2135b0db	1433	next->next = tcp_seg_copy(&inseg);
Yann	0:f30e2135b0db	1434	if (next->next != NULL) {
Yann	0:f30e2135b0db	1435	if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
Yann	0:f30e2135b0db	1436	/* We need to trim the last segment. */
Yann	0:f30e2135b0db	1437	next->len = (u16_t)(seqno - next->tcphdr->seqno);
Yann	0:f30e2135b0db	1438	pbuf_realloc(next->p, next->len);
Yann	0:f30e2135b0db	1439	}
Yann	0:f30e2135b0db	1440	/* check if the remote side overruns our receive window */
Yann	0:f30e2135b0db	1441	if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
Yann	0:f30e2135b0db	1442	LWIP_DEBUGF(TCP_INPUT_DEBUG,
Yann	0:f30e2135b0db	1443	("tcp_receive: other end overran receive window"
Yann	0:f30e2135b0db	1444	"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
Yann	0:f30e2135b0db	1445	seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
Yann	0:f30e2135b0db	1446	if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
Yann	0:f30e2135b0db	1447	/* Must remove the FIN from the header as we're trimming
Yann	0:f30e2135b0db	1448	* that byte of sequence-space from the packet */
Yann	0:f30e2135b0db	1449	TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
Yann	0:f30e2135b0db	1450	}
Yann	0:f30e2135b0db	1451	/* Adjust length of segment to fit in the window. */
Yann	0:f30e2135b0db	1452	next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
Yann	0:f30e2135b0db	1453	pbuf_realloc(next->next->p, next->next->len);
Yann	0:f30e2135b0db	1454	tcplen = TCP_TCPLEN(next->next);
Yann	0:f30e2135b0db	1455	LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
Yann	0:f30e2135b0db	1456	(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
Yann	0:f30e2135b0db	1457	}
Yann	0:f30e2135b0db	1458	}
Yann	0:f30e2135b0db	1459	break;
Yann	0:f30e2135b0db	1460	}
Yann	0:f30e2135b0db	1461	}
Yann	0:f30e2135b0db	1462	prev = next;
Yann	0:f30e2135b0db	1463	}
Yann	0:f30e2135b0db	1464	}
Yann	0:f30e2135b0db	1465	#endif /* TCP_QUEUE_OOSEQ */
Yann	0:f30e2135b0db	1466
Yann	0:f30e2135b0db	1467	}
Yann	0:f30e2135b0db	1468	} else {
Yann	0:f30e2135b0db	1469	/* The incoming segment is not withing the window. */
Yann	0:f30e2135b0db	1470	tcp_send_empty_ack(pcb);
Yann	0:f30e2135b0db	1471	}
Yann	0:f30e2135b0db	1472	} else {
Yann	0:f30e2135b0db	1473	/* Segments with length 0 is taken care of here. Segments that
Yann	0:f30e2135b0db	1474	fall out of the window are ACKed. */
Yann	0:f30e2135b0db	1475	/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) \|\|
Yann	0:f30e2135b0db	1476	TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
Yann	0:f30e2135b0db	1477	if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
Yann	0:f30e2135b0db	1478	tcp_ack_now(pcb);
Yann	0:f30e2135b0db	1479	}
Yann	0:f30e2135b0db	1480	}
Yann	0:f30e2135b0db	1481	}
Yann	0:f30e2135b0db	1482
Yann	0:f30e2135b0db	1483	/**
Yann	0:f30e2135b0db	1484	* Parses the options contained in the incoming segment.
Yann	0:f30e2135b0db	1485	*
Yann	0:f30e2135b0db	1486	* Called from tcp_listen_input() and tcp_process().
Yann	0:f30e2135b0db	1487	* Currently, only the MSS option is supported!
Yann	0:f30e2135b0db	1488	*
Yann	0:f30e2135b0db	1489	* @param pcb the tcp_pcb for which a segment arrived
Yann	0:f30e2135b0db	1490	*/
Yann	0:f30e2135b0db	1491	static void
Yann	0:f30e2135b0db	1492	tcp_parseopt(struct tcp_pcb *pcb)
Yann	0:f30e2135b0db	1493	{
Yann	0:f30e2135b0db	1494	u16_t c, max_c;
Yann	0:f30e2135b0db	1495	u16_t mss;
Yann	0:f30e2135b0db	1496	u8_t *opts, opt;
Yann	0:f30e2135b0db	1497	#if LWIP_TCP_TIMESTAMPS
Yann	0:f30e2135b0db	1498	u32_t tsval;
Yann	0:f30e2135b0db	1499	#endif
Yann	0:f30e2135b0db	1500
Yann	0:f30e2135b0db	1501	opts = (u8_t *)tcphdr + TCP_HLEN;
Yann	0:f30e2135b0db	1502
Yann	0:f30e2135b0db	1503	/* Parse the TCP MSS option, if present. */
Yann	0:f30e2135b0db	1504	if(TCPH_HDRLEN(tcphdr) > 0x5) {
Yann	0:f30e2135b0db	1505	max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
Yann	0:f30e2135b0db	1506	for (c = 0; c < max_c; ) {
Yann	0:f30e2135b0db	1507	opt = opts[c];
Yann	0:f30e2135b0db	1508	switch (opt) {
Yann	0:f30e2135b0db	1509	case 0x00:
Yann	0:f30e2135b0db	1510	/* End of options. */
Yann	0:f30e2135b0db	1511	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
Yann	0:f30e2135b0db	1512	return;
Yann	0:f30e2135b0db	1513	case 0x01:
Yann	0:f30e2135b0db	1514	/* NOP option. */
Yann	0:f30e2135b0db	1515	++c;
Yann	0:f30e2135b0db	1516	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
Yann	0:f30e2135b0db	1517	break;
Yann	0:f30e2135b0db	1518	case 0x02:
Yann	0:f30e2135b0db	1519	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
Yann	0:f30e2135b0db	1520	if (opts[c + 1] != 0x04 \|\| c + 0x04 > max_c) {
Yann	0:f30e2135b0db	1521	/* Bad length */
Yann	0:f30e2135b0db	1522	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
Yann	0:f30e2135b0db	1523	return;
Yann	0:f30e2135b0db	1524	}
Yann	0:f30e2135b0db	1525	/* An MSS option with the right option length. */
Yann	0:f30e2135b0db	1526	mss = (opts[c + 2] << 8) \| opts[c + 3];
Yann	0:f30e2135b0db	1527	/* Limit the mss to the configured TCP_MSS and prevent division by zero */
Yann	0:f30e2135b0db	1528	pcb->mss = ((mss > TCP_MSS) \|\| (mss == 0)) ? TCP_MSS : mss;
Yann	0:f30e2135b0db	1529	/* Advance to next option */
Yann	0:f30e2135b0db	1530	c += 0x04;
Yann	0:f30e2135b0db	1531	break;
Yann	0:f30e2135b0db	1532	#if LWIP_TCP_TIMESTAMPS
Yann	0:f30e2135b0db	1533	case 0x08:
Yann	0:f30e2135b0db	1534	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
Yann	0:f30e2135b0db	1535	if (opts[c + 1] != 0x0A \|\| c + 0x0A > max_c) {
Yann	0:f30e2135b0db	1536	/* Bad length */
Yann	0:f30e2135b0db	1537	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
Yann	0:f30e2135b0db	1538	return;
Yann	0:f30e2135b0db	1539	}
Yann	0:f30e2135b0db	1540	/* TCP timestamp option with valid length */
Yann	0:f30e2135b0db	1541	tsval = (opts[c+2]) \| (opts[c+3] << 8) \|
Yann	0:f30e2135b0db	1542	(opts[c+4] << 16) \| (opts[c+5] << 24);
Yann	0:f30e2135b0db	1543	if (flags & TCP_SYN) {
Yann	0:f30e2135b0db	1544	pcb->ts_recent = ntohl(tsval);
Yann	0:f30e2135b0db	1545	pcb->flags \|= TF_TIMESTAMP;
Yann	0:f30e2135b0db	1546	} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
Yann	0:f30e2135b0db	1547	pcb->ts_recent = ntohl(tsval);
Yann	0:f30e2135b0db	1548	}
Yann	0:f30e2135b0db	1549	/* Advance to next option */
Yann	0:f30e2135b0db	1550	c += 0x0A;
Yann	0:f30e2135b0db	1551	break;
Yann	0:f30e2135b0db	1552	#endif
Yann	0:f30e2135b0db	1553	default:
Yann	0:f30e2135b0db	1554	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
Yann	0:f30e2135b0db	1555	if (opts[c + 1] == 0) {
Yann	0:f30e2135b0db	1556	LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
Yann	0:f30e2135b0db	1557	/* If the length field is zero, the options are malformed
Yann	0:f30e2135b0db	1558	and we don't process them further. */
Yann	0:f30e2135b0db	1559	return;
Yann	0:f30e2135b0db	1560	}
Yann	0:f30e2135b0db	1561	/* All other options have a length field, so that we easily
Yann	0:f30e2135b0db	1562	can skip past them. */
Yann	0:f30e2135b0db	1563	c += opts[c + 1];
Yann	0:f30e2135b0db	1564	}
Yann	0:f30e2135b0db	1565	}
Yann	0:f30e2135b0db	1566	}
Yann	0:f30e2135b0db	1567	}
Yann	0:f30e2135b0db	1568
Yann	0:f30e2135b0db	1569	#endif /* LWIP_TCP */

Repository toolbox

Export to desktop IDE

Build repository

Repository details

Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	09 Feb 2011
Imports:	33
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	3
Followers:	1

NetServices/lwip/core/tcp_in.c@1:995212d326ca, 2011-02-11 (annotated)

Who changed what in which revision?

Repository toolbox

Repository details

Important Information for this Arm website

Access Warning