Bonjour - First step: AutoIP compiled in and working

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Darran Shepherd / Mbed 2 deprecated Bonjour

First step: AutoIP compiled in and working

lwip/netif/ppp/vj.c@1:4218cacaf696, 2010-06-18 (annotated)

Committer:: darran
Date:: Fri Jun 18 15:54:21 2010 +0000
Revision:: 1:4218cacaf696
Parent:: 0:55a05330f8cc

Who changed what in which revision?

User	Revision	Line number	New contents of line
darran	0:55a05330f8cc	1	/*
darran	0:55a05330f8cc	2	* Routines to compress and uncompess tcp packets (for transmission
darran	0:55a05330f8cc	3	* over low speed serial lines.
darran	0:55a05330f8cc	4	*
darran	0:55a05330f8cc	5	* Copyright (c) 1989 Regents of the University of California.
darran	0:55a05330f8cc	6	* All rights reserved.
darran	0:55a05330f8cc	7	*
darran	0:55a05330f8cc	8	* Redistribution and use in source and binary forms are permitted
darran	0:55a05330f8cc	9	* provided that the above copyright notice and this paragraph are
darran	0:55a05330f8cc	10	* duplicated in all such forms and that any documentation,
darran	0:55a05330f8cc	11	* advertising materials, and other materials related to such
darran	0:55a05330f8cc	12	* distribution and use acknowledge that the software was developed
darran	0:55a05330f8cc	13	* by the University of California, Berkeley. The name of the
darran	0:55a05330f8cc	14	* University may not be used to endorse or promote products derived
darran	0:55a05330f8cc	15	* from this software without specific prior written permission.
darran	0:55a05330f8cc	16	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
darran	0:55a05330f8cc	17	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
darran	0:55a05330f8cc	18	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
darran	0:55a05330f8cc	19	*
darran	0:55a05330f8cc	20	* Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
darran	0:55a05330f8cc	21	* Initial distribution.
darran	0:55a05330f8cc	22	*
darran	0:55a05330f8cc	23	* Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au,
darran	0:55a05330f8cc	24	* so that the entire packet being decompressed doesn't have
darran	0:55a05330f8cc	25	* to be in contiguous memory (just the compressed header).
darran	0:55a05330f8cc	26	*
darran	0:55a05330f8cc	27	* Modified March 1998 by Guy Lancaster, glanca@gesn.com,
darran	0:55a05330f8cc	28	* for a 16 bit processor.
darran	0:55a05330f8cc	29	*/
darran	0:55a05330f8cc	30
darran	0:55a05330f8cc	31	#include "lwip/opt.h"
darran	0:55a05330f8cc	32
darran	0:55a05330f8cc	33	#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
darran	0:55a05330f8cc	34
darran	0:55a05330f8cc	35	#include "ppp.h"
darran	0:55a05330f8cc	36	#include "pppdebug.h"
darran	0:55a05330f8cc	37
darran	0:55a05330f8cc	38	#include "vj.h"
darran	0:55a05330f8cc	39
darran	0:55a05330f8cc	40	#include <string.h>
darran	0:55a05330f8cc	41
darran	0:55a05330f8cc	42	#if VJ_SUPPORT
darran	0:55a05330f8cc	43
darran	0:55a05330f8cc	44	#if LINK_STATS
darran	0:55a05330f8cc	45	#define INCR(counter) ++comp->stats.counter
darran	0:55a05330f8cc	46	#else
darran	0:55a05330f8cc	47	#define INCR(counter)
darran	0:55a05330f8cc	48	#endif
darran	0:55a05330f8cc	49
darran	0:55a05330f8cc	50	void
darran	0:55a05330f8cc	51	vj_compress_init(struct vjcompress *comp)
darran	0:55a05330f8cc	52	{
darran	0:55a05330f8cc	53	register u_char i;
darran	0:55a05330f8cc	54	register struct cstate *tstate = comp->tstate;
darran	0:55a05330f8cc	55
darran	0:55a05330f8cc	56	#if MAX_SLOTS == 0
darran	0:55a05330f8cc	57	memset((char )comp, 0, sizeof(comp));
darran	0:55a05330f8cc	58	#endif
darran	0:55a05330f8cc	59	comp->maxSlotIndex = MAX_SLOTS - 1;
darran	0:55a05330f8cc	60	comp->compressSlot = 0; /* Disable slot ID compression by default. */
darran	0:55a05330f8cc	61	for (i = MAX_SLOTS - 1; i > 0; --i) {
darran	0:55a05330f8cc	62	tstate[i].cs_id = i;
darran	0:55a05330f8cc	63	tstate[i].cs_next = &tstate[i - 1];
darran	0:55a05330f8cc	64	}
darran	0:55a05330f8cc	65	tstate[0].cs_next = &tstate[MAX_SLOTS - 1];
darran	0:55a05330f8cc	66	tstate[0].cs_id = 0;
darran	0:55a05330f8cc	67	comp->last_cs = &tstate[0];
darran	0:55a05330f8cc	68	comp->last_recv = 255;
darran	0:55a05330f8cc	69	comp->last_xmit = 255;
darran	0:55a05330f8cc	70	comp->flags = VJF_TOSS;
darran	0:55a05330f8cc	71	}
darran	0:55a05330f8cc	72
darran	0:55a05330f8cc	73
darran	0:55a05330f8cc	74	/* ENCODE encodes a number that is known to be non-zero. ENCODEZ
darran	0:55a05330f8cc	75	* checks for zero (since zero has to be encoded in the long, 3 byte
darran	0:55a05330f8cc	76	* form).
darran	0:55a05330f8cc	77	*/
darran	0:55a05330f8cc	78	#define ENCODE(n) { \
darran	0:55a05330f8cc	79	if ((u_short)(n) >= 256) { \
darran	0:55a05330f8cc	80	*cp++ = 0; \
darran	0:55a05330f8cc	81	cp[1] = (u_char)(n); \
darran	0:55a05330f8cc	82	cp[0] = (u_char)((n) >> 8); \
darran	0:55a05330f8cc	83	cp += 2; \
darran	0:55a05330f8cc	84	} else { \
darran	0:55a05330f8cc	85	*cp++ = (u_char)(n); \
darran	0:55a05330f8cc	86	} \
darran	0:55a05330f8cc	87	}
darran	0:55a05330f8cc	88	#define ENCODEZ(n) { \
darran	0:55a05330f8cc	89	if ((u_short)(n) >= 256 \|\| (u_short)(n) == 0) { \
darran	0:55a05330f8cc	90	*cp++ = 0; \
darran	0:55a05330f8cc	91	cp[1] = (u_char)(n); \
darran	0:55a05330f8cc	92	cp[0] = (u_char)((n) >> 8); \
darran	0:55a05330f8cc	93	cp += 2; \
darran	0:55a05330f8cc	94	} else { \
darran	0:55a05330f8cc	95	*cp++ = (u_char)(n); \
darran	0:55a05330f8cc	96	} \
darran	0:55a05330f8cc	97	}
darran	0:55a05330f8cc	98
darran	0:55a05330f8cc	99	#define DECODEL(f) { \
darran	0:55a05330f8cc	100	if (*cp == 0) {\
darran	0:55a05330f8cc	101	u32_t tmp = ntohl(f) + ((cp[1] << 8) \| cp[2]); \
darran	0:55a05330f8cc	102	(f) = htonl(tmp); \
darran	0:55a05330f8cc	103	cp += 3; \
darran	0:55a05330f8cc	104	} else { \
darran	0:55a05330f8cc	105	u32_t tmp = ntohl(f) + (u32_t)*cp++; \
darran	0:55a05330f8cc	106	(f) = htonl(tmp); \
darran	0:55a05330f8cc	107	} \
darran	0:55a05330f8cc	108	}
darran	0:55a05330f8cc	109
darran	0:55a05330f8cc	110	#define DECODES(f) { \
darran	0:55a05330f8cc	111	if (*cp == 0) {\
darran	0:55a05330f8cc	112	u_short tmp = ntohs(f) + (((u_short)cp[1] << 8) \| cp[2]); \
darran	0:55a05330f8cc	113	(f) = htons(tmp); \
darran	0:55a05330f8cc	114	cp += 3; \
darran	0:55a05330f8cc	115	} else { \
darran	0:55a05330f8cc	116	u_short tmp = ntohs(f) + (u_short)*cp++; \
darran	0:55a05330f8cc	117	(f) = htons(tmp); \
darran	0:55a05330f8cc	118	} \
darran	0:55a05330f8cc	119	}
darran	0:55a05330f8cc	120
darran	0:55a05330f8cc	121	#define DECODEU(f) { \
darran	0:55a05330f8cc	122	if (*cp == 0) {\
darran	0:55a05330f8cc	123	(f) = htons(((u_short)cp[1] << 8) \| cp[2]); \
darran	0:55a05330f8cc	124	cp += 3; \
darran	0:55a05330f8cc	125	} else { \
darran	0:55a05330f8cc	126	(f) = htons((u_short)*cp++); \
darran	0:55a05330f8cc	127	} \
darran	0:55a05330f8cc	128	}
darran	0:55a05330f8cc	129
darran	0:55a05330f8cc	130	/*
darran	0:55a05330f8cc	131	* vj_compress_tcp - Attempt to do Van Jacobson header compression on a
darran	0:55a05330f8cc	132	* packet. This assumes that nb and comp are not null and that the first
darran	0:55a05330f8cc	133	* buffer of the chain contains a valid IP header.
darran	0:55a05330f8cc	134	* Return the VJ type code indicating whether or not the packet was
darran	0:55a05330f8cc	135	* compressed.
darran	0:55a05330f8cc	136	*/
darran	0:55a05330f8cc	137	u_int
darran	0:55a05330f8cc	138	vj_compress_tcp(struct vjcompress comp, struct pbuf pb)
darran	0:55a05330f8cc	139	{
darran	0:55a05330f8cc	140	register struct ip_hdr ip = (struct ip_hdr )pb->payload;
darran	0:55a05330f8cc	141	register struct cstate *cs = comp->last_cs->cs_next;
darran	0:55a05330f8cc	142	register u_short hlen = IPH_HL(ip);
darran	0:55a05330f8cc	143	register struct tcp_hdr *oth;
darran	0:55a05330f8cc	144	register struct tcp_hdr *th;
darran	0:55a05330f8cc	145	register u_short deltaS, deltaA;
darran	0:55a05330f8cc	146	register u_long deltaL;
darran	0:55a05330f8cc	147	register u_int changes = 0;
darran	0:55a05330f8cc	148	u_char new_seq[16];
darran	0:55a05330f8cc	149	register u_char *cp = new_seq;
darran	0:55a05330f8cc	150
darran	0:55a05330f8cc	151	/*
darran	0:55a05330f8cc	152	* Check that the packet is IP proto TCP.
darran	0:55a05330f8cc	153	*/
darran	0:55a05330f8cc	154	if (IPH_PROTO(ip) != IP_PROTO_TCP) {
darran	0:55a05330f8cc	155	return (TYPE_IP);
darran	0:55a05330f8cc	156	}
darran	0:55a05330f8cc	157
darran	0:55a05330f8cc	158	/*
darran	0:55a05330f8cc	159	* Bail if this is an IP fragment or if the TCP packet isn't
darran	0:55a05330f8cc	160	* `compressible' (i.e., ACK isn't set or some other control bit is
darran	0:55a05330f8cc	161	* set).
darran	0:55a05330f8cc	162	*/
darran	0:55a05330f8cc	163	if ((IPH_OFFSET(ip) & htons(0x3fff)) \|\| pb->tot_len < 40) {
darran	0:55a05330f8cc	164	return (TYPE_IP);
darran	0:55a05330f8cc	165	}
darran	0:55a05330f8cc	166	th = (struct tcp_hdr )&((long )ip)[hlen];
darran	0:55a05330f8cc	167	if ((TCPH_FLAGS(th) & (TCP_SYN\|TCP_FIN\|TCP_RST\|TCP_ACK)) != TCP_ACK) {
darran	0:55a05330f8cc	168	return (TYPE_IP);
darran	0:55a05330f8cc	169	}
darran	0:55a05330f8cc	170	/*
darran	0:55a05330f8cc	171	* Packet is compressible -- we're going to send either a
darran	0:55a05330f8cc	172	* COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way we need
darran	0:55a05330f8cc	173	* to locate (or create) the connection state. Special case the
darran	0:55a05330f8cc	174	* most recently used connection since it's most likely to be used
darran	0:55a05330f8cc	175	* again & we don't have to do any reordering if it's used.
darran	0:55a05330f8cc	176	*/
darran	0:55a05330f8cc	177	INCR(vjs_packets);
darran	0:55a05330f8cc	178	if (!ip_addr_cmp(&ip->src, &cs->cs_ip.src)
darran	0:55a05330f8cc	179	\|\| !ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
darran	0:55a05330f8cc	180	\|\| (long )th != ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
darran	0:55a05330f8cc	181	/*
darran	0:55a05330f8cc	182	* Wasn't the first -- search for it.
darran	0:55a05330f8cc	183	*
darran	0:55a05330f8cc	184	* States are kept in a circularly linked list with
darran	0:55a05330f8cc	185	* last_cs pointing to the end of the list. The
darran	0:55a05330f8cc	186	* list is kept in lru order by moving a state to the
darran	0:55a05330f8cc	187	* head of the list whenever it is referenced. Since
darran	0:55a05330f8cc	188	* the list is short and, empirically, the connection
darran	0:55a05330f8cc	189	* we want is almost always near the front, we locate
darran	0:55a05330f8cc	190	* states via linear search. If we don't find a state
darran	0:55a05330f8cc	191	* for the datagram, the oldest state is (re-)used.
darran	0:55a05330f8cc	192	*/
darran	0:55a05330f8cc	193	register struct cstate *lcs;
darran	0:55a05330f8cc	194	register struct cstate *lastcs = comp->last_cs;
darran	0:55a05330f8cc	195
darran	0:55a05330f8cc	196	do {
darran	0:55a05330f8cc	197	lcs = cs; cs = cs->cs_next;
darran	0:55a05330f8cc	198	INCR(vjs_searches);
darran	0:55a05330f8cc	199	if (ip_addr_cmp(&ip->src, &cs->cs_ip.src)
darran	0:55a05330f8cc	200	&& ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
darran	0:55a05330f8cc	201	&& (long )th == ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
darran	0:55a05330f8cc	202	goto found;
darran	0:55a05330f8cc	203	}
darran	0:55a05330f8cc	204	} while (cs != lastcs);
darran	0:55a05330f8cc	205
darran	0:55a05330f8cc	206	/*
darran	0:55a05330f8cc	207	* Didn't find it -- re-use oldest cstate. Send an
darran	0:55a05330f8cc	208	* uncompressed packet that tells the other side what
darran	0:55a05330f8cc	209	* connection number we're using for this conversation.
darran	0:55a05330f8cc	210	* Note that since the state list is circular, the oldest
darran	0:55a05330f8cc	211	* state points to the newest and we only need to set
darran	0:55a05330f8cc	212	* last_cs to update the lru linkage.
darran	0:55a05330f8cc	213	*/
darran	0:55a05330f8cc	214	INCR(vjs_misses);
darran	0:55a05330f8cc	215	comp->last_cs = lcs;
darran	0:55a05330f8cc	216	hlen += TCPH_OFFSET(th);
darran	0:55a05330f8cc	217	hlen <<= 2;
darran	0:55a05330f8cc	218	/* Check that the IP/TCP headers are contained in the first buffer. */
darran	0:55a05330f8cc	219	if (hlen > pb->len) {
darran	0:55a05330f8cc	220	return (TYPE_IP);
darran	0:55a05330f8cc	221	}
darran	0:55a05330f8cc	222	goto uncompressed;
darran	0:55a05330f8cc	223
darran	0:55a05330f8cc	224	found:
darran	0:55a05330f8cc	225	/*
darran	0:55a05330f8cc	226	* Found it -- move to the front on the connection list.
darran	0:55a05330f8cc	227	*/
darran	0:55a05330f8cc	228	if (cs == lastcs) {
darran	0:55a05330f8cc	229	comp->last_cs = lcs;
darran	0:55a05330f8cc	230	} else {
darran	0:55a05330f8cc	231	lcs->cs_next = cs->cs_next;
darran	0:55a05330f8cc	232	cs->cs_next = lastcs->cs_next;
darran	0:55a05330f8cc	233	lastcs->cs_next = cs;
darran	0:55a05330f8cc	234	}
darran	0:55a05330f8cc	235	}
darran	0:55a05330f8cc	236
darran	0:55a05330f8cc	237	oth = (struct tcp_hdr )&((long )&cs->cs_ip)[hlen];
darran	0:55a05330f8cc	238	deltaS = hlen;
darran	0:55a05330f8cc	239	hlen += TCPH_OFFSET(th);
darran	0:55a05330f8cc	240	hlen <<= 2;
darran	0:55a05330f8cc	241	/* Check that the IP/TCP headers are contained in the first buffer. */
darran	0:55a05330f8cc	242	if (hlen > pb->len) {
darran	0:55a05330f8cc	243	PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
darran	0:55a05330f8cc	244	return (TYPE_IP);
darran	0:55a05330f8cc	245	}
darran	0:55a05330f8cc	246
darran	0:55a05330f8cc	247	/*
darran	0:55a05330f8cc	248	* Make sure that only what we expect to change changed. The first
darran	0:55a05330f8cc	249	* line of the `if' checks the IP protocol version, header length &
darran	0:55a05330f8cc	250	* type of service. The 2nd line checks the "Don't fragment" bit.
darran	0:55a05330f8cc	251	* The 3rd line checks the time-to-live and protocol (the protocol
darran	0:55a05330f8cc	252	* check is unnecessary but costless). The 4th line checks the TCP
darran	0:55a05330f8cc	253	* header length. The 5th line checks IP options, if any. The 6th
darran	0:55a05330f8cc	254	* line checks TCP options, if any. If any of these things are
darran	0:55a05330f8cc	255	* different between the previous & current datagram, we send the
darran	0:55a05330f8cc	256	* current datagram `uncompressed'.
darran	0:55a05330f8cc	257	*/
darran	0:55a05330f8cc	258	if (((u_short )ip)[0] != ((u_short )&cs->cs_ip)[0]
darran	0:55a05330f8cc	259	\|\| ((u_short )ip)[3] != ((u_short )&cs->cs_ip)[3]
darran	0:55a05330f8cc	260	\|\| ((u_short )ip)[4] != ((u_short )&cs->cs_ip)[4]
darran	0:55a05330f8cc	261	\|\| TCPH_OFFSET(th) != TCPH_OFFSET(oth)
darran	0:55a05330f8cc	262	\|\| (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2))
darran	0:55a05330f8cc	263	\|\| (TCPH_OFFSET(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_OFFSET(th) - 5) << 2))) {
darran	0:55a05330f8cc	264	goto uncompressed;
darran	0:55a05330f8cc	265	}
darran	0:55a05330f8cc	266
darran	0:55a05330f8cc	267	/*
darran	0:55a05330f8cc	268	* Figure out which of the changing fields changed. The
darran	0:55a05330f8cc	269	* receiver expects changes in the order: urgent, window,
darran	0:55a05330f8cc	270	* ack, seq (the order minimizes the number of temporaries
darran	0:55a05330f8cc	271	* needed in this section of code).
darran	0:55a05330f8cc	272	*/
darran	0:55a05330f8cc	273	if (TCPH_FLAGS(th) & TCP_URG) {
darran	0:55a05330f8cc	274	deltaS = ntohs(th->urgp);
darran	0:55a05330f8cc	275	ENCODEZ(deltaS);
darran	0:55a05330f8cc	276	changes \|= NEW_U;
darran	0:55a05330f8cc	277	} else if (th->urgp != oth->urgp) {
darran	0:55a05330f8cc	278	/* argh! URG not set but urp changed -- a sensible
darran	0:55a05330f8cc	279	* implementation should never do this but RFC793
darran	0:55a05330f8cc	280	* doesn't prohibit the change so we have to deal
darran	0:55a05330f8cc	281	* with it. */
darran	0:55a05330f8cc	282	goto uncompressed;
darran	0:55a05330f8cc	283	}
darran	0:55a05330f8cc	284
darran	0:55a05330f8cc	285	if ((deltaS = (u_short)(ntohs(th->wnd) - ntohs(oth->wnd))) != 0) {
darran	0:55a05330f8cc	286	ENCODE(deltaS);
darran	0:55a05330f8cc	287	changes \|= NEW_W;
darran	0:55a05330f8cc	288	}
darran	0:55a05330f8cc	289
darran	0:55a05330f8cc	290	if ((deltaL = ntohl(th->ackno) - ntohl(oth->ackno)) != 0) {
darran	0:55a05330f8cc	291	if (deltaL > 0xffff) {
darran	0:55a05330f8cc	292	goto uncompressed;
darran	0:55a05330f8cc	293	}
darran	0:55a05330f8cc	294	deltaA = (u_short)deltaL;
darran	0:55a05330f8cc	295	ENCODE(deltaA);
darran	0:55a05330f8cc	296	changes \|= NEW_A;
darran	0:55a05330f8cc	297	}
darran	0:55a05330f8cc	298
darran	0:55a05330f8cc	299	if ((deltaL = ntohl(th->seqno) - ntohl(oth->seqno)) != 0) {
darran	0:55a05330f8cc	300	if (deltaL > 0xffff) {
darran	0:55a05330f8cc	301	goto uncompressed;
darran	0:55a05330f8cc	302	}
darran	0:55a05330f8cc	303	deltaS = (u_short)deltaL;
darran	0:55a05330f8cc	304	ENCODE(deltaS);
darran	0:55a05330f8cc	305	changes \|= NEW_S;
darran	0:55a05330f8cc	306	}
darran	0:55a05330f8cc	307
darran	0:55a05330f8cc	308	switch(changes) {
darran	0:55a05330f8cc	309	case 0:
darran	0:55a05330f8cc	310	/*
darran	0:55a05330f8cc	311	* Nothing changed. If this packet contains data and the
darran	0:55a05330f8cc	312	* last one didn't, this is probably a data packet following
darran	0:55a05330f8cc	313	* an ack (normal on an interactive connection) and we send
darran	0:55a05330f8cc	314	* it compressed. Otherwise it's probably a retransmit,
darran	0:55a05330f8cc	315	* retransmitted ack or window probe. Send it uncompressed
darran	0:55a05330f8cc	316	* in case the other side missed the compressed version.
darran	0:55a05330f8cc	317	*/
darran	0:55a05330f8cc	318	if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) &&
darran	0:55a05330f8cc	319	ntohs(IPH_LEN(&cs->cs_ip)) == hlen) {
darran	0:55a05330f8cc	320	break;
darran	0:55a05330f8cc	321	}
darran	0:55a05330f8cc	322
darran	0:55a05330f8cc	323	/* (fall through) */
darran	0:55a05330f8cc	324
darran	0:55a05330f8cc	325	case SPECIAL_I:
darran	0:55a05330f8cc	326	case SPECIAL_D:
darran	0:55a05330f8cc	327	/*
darran	0:55a05330f8cc	328	* actual changes match one of our special case encodings --
darran	0:55a05330f8cc	329	* send packet uncompressed.
darran	0:55a05330f8cc	330	*/
darran	0:55a05330f8cc	331	goto uncompressed;
darran	0:55a05330f8cc	332
darran	0:55a05330f8cc	333	case NEW_S\|NEW_A:
darran	0:55a05330f8cc	334	if (deltaS == deltaA && deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
darran	0:55a05330f8cc	335	/* special case for echoed terminal traffic */
darran	0:55a05330f8cc	336	changes = SPECIAL_I;
darran	0:55a05330f8cc	337	cp = new_seq;
darran	0:55a05330f8cc	338	}
darran	0:55a05330f8cc	339	break;
darran	0:55a05330f8cc	340
darran	0:55a05330f8cc	341	case NEW_S:
darran	0:55a05330f8cc	342	if (deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
darran	0:55a05330f8cc	343	/* special case for data xfer */
darran	0:55a05330f8cc	344	changes = SPECIAL_D;
darran	0:55a05330f8cc	345	cp = new_seq;
darran	0:55a05330f8cc	346	}
darran	0:55a05330f8cc	347	break;
darran	0:55a05330f8cc	348	}
darran	0:55a05330f8cc	349
darran	0:55a05330f8cc	350	deltaS = (u_short)(ntohs(IPH_ID(ip)) - ntohs(IPH_ID(&cs->cs_ip)));
darran	0:55a05330f8cc	351	if (deltaS != 1) {
darran	0:55a05330f8cc	352	ENCODEZ(deltaS);
darran	0:55a05330f8cc	353	changes \|= NEW_I;
darran	0:55a05330f8cc	354	}
darran	0:55a05330f8cc	355	if (TCPH_FLAGS(th) & TCP_PSH) {
darran	0:55a05330f8cc	356	changes \|= TCP_PUSH_BIT;
darran	0:55a05330f8cc	357	}
darran	0:55a05330f8cc	358	/*
darran	0:55a05330f8cc	359	* Grab the cksum before we overwrite it below. Then update our
darran	0:55a05330f8cc	360	* state with this packet's header.
darran	0:55a05330f8cc	361	*/
darran	0:55a05330f8cc	362	deltaA = ntohs(th->chksum);
darran	0:55a05330f8cc	363	BCOPY(ip, &cs->cs_ip, hlen);
darran	0:55a05330f8cc	364
darran	0:55a05330f8cc	365	/*
darran	0:55a05330f8cc	366	* We want to use the original packet as our compressed packet.
darran	0:55a05330f8cc	367	* (cp - new_seq) is the number of bytes we need for compressed
darran	0:55a05330f8cc	368	* sequence numbers. In addition we need one byte for the change
darran	0:55a05330f8cc	369	* mask, one for the connection id and two for the tcp checksum.
darran	0:55a05330f8cc	370	* So, (cp - new_seq) + 4 bytes of header are needed. hlen is how
darran	0:55a05330f8cc	371	* many bytes of the original packet to toss so subtract the two to
darran	0:55a05330f8cc	372	* get the new packet size.
darran	0:55a05330f8cc	373	*/
darran	0:55a05330f8cc	374	deltaS = (u_short)(cp - new_seq);
darran	0:55a05330f8cc	375	if (!comp->compressSlot \|\| comp->last_xmit != cs->cs_id) {
darran	0:55a05330f8cc	376	comp->last_xmit = cs->cs_id;
darran	0:55a05330f8cc	377	hlen -= deltaS + 4;
darran	0:55a05330f8cc	378	if(pbuf_header(pb, -hlen)){
darran	0:55a05330f8cc	379	/* Can we cope with this failing? Just assert for now */
darran	0:55a05330f8cc	380	LWIP_ASSERT("pbuf_header failed\n", 0);
darran	0:55a05330f8cc	381	}
darran	0:55a05330f8cc	382	cp = (u_char *)pb->payload;
darran	0:55a05330f8cc	383	*cp++ = (u_char)(changes \| NEW_C);
darran	0:55a05330f8cc	384	*cp++ = cs->cs_id;
darran	0:55a05330f8cc	385	} else {
darran	0:55a05330f8cc	386	hlen -= deltaS + 3;
darran	0:55a05330f8cc	387	if(pbuf_header(pb, -hlen)) {
darran	0:55a05330f8cc	388	/* Can we cope with this failing? Just assert for now */
darran	0:55a05330f8cc	389	LWIP_ASSERT("pbuf_header failed\n", 0);
darran	0:55a05330f8cc	390	}
darran	0:55a05330f8cc	391	cp = (u_char *)pb->payload;
darran	0:55a05330f8cc	392	*cp++ = (u_char)changes;
darran	0:55a05330f8cc	393	}
darran	0:55a05330f8cc	394	*cp++ = (u_char)(deltaA >> 8);
darran	0:55a05330f8cc	395	*cp++ = (u_char)deltaA;
darran	0:55a05330f8cc	396	BCOPY(new_seq, cp, deltaS);
darran	0:55a05330f8cc	397	INCR(vjs_compressed);
darran	0:55a05330f8cc	398	return (TYPE_COMPRESSED_TCP);
darran	0:55a05330f8cc	399
darran	0:55a05330f8cc	400	/*
darran	0:55a05330f8cc	401	* Update connection state cs & send uncompressed packet (that is,
darran	0:55a05330f8cc	402	* a regular ip/tcp packet but with the 'conversation id' we hope
darran	0:55a05330f8cc	403	* to use on future compressed packets in the protocol field).
darran	0:55a05330f8cc	404	*/
darran	0:55a05330f8cc	405	uncompressed:
darran	0:55a05330f8cc	406	BCOPY(ip, &cs->cs_ip, hlen);
darran	0:55a05330f8cc	407	IPH_PROTO_SET(ip, cs->cs_id);
darran	0:55a05330f8cc	408	comp->last_xmit = cs->cs_id;
darran	0:55a05330f8cc	409	return (TYPE_UNCOMPRESSED_TCP);
darran	0:55a05330f8cc	410	}
darran	0:55a05330f8cc	411
darran	0:55a05330f8cc	412	/*
darran	0:55a05330f8cc	413	* Called when we may have missed a packet.
darran	0:55a05330f8cc	414	*/
darran	0:55a05330f8cc	415	void
darran	0:55a05330f8cc	416	vj_uncompress_err(struct vjcompress *comp)
darran	0:55a05330f8cc	417	{
darran	0:55a05330f8cc	418	comp->flags \|= VJF_TOSS;
darran	0:55a05330f8cc	419	INCR(vjs_errorin);
darran	0:55a05330f8cc	420	}
darran	0:55a05330f8cc	421
darran	0:55a05330f8cc	422	/*
darran	0:55a05330f8cc	423	* "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP.
darran	0:55a05330f8cc	424	* Return 0 on success, -1 on failure.
darran	0:55a05330f8cc	425	*/
darran	0:55a05330f8cc	426	int
darran	0:55a05330f8cc	427	vj_uncompress_uncomp(struct pbuf nb, struct vjcompress comp)
darran	0:55a05330f8cc	428	{
darran	0:55a05330f8cc	429	register u_int hlen;
darran	0:55a05330f8cc	430	register struct cstate *cs;
darran	0:55a05330f8cc	431	register struct ip_hdr *ip;
darran	0:55a05330f8cc	432
darran	0:55a05330f8cc	433	ip = (struct ip_hdr *)nb->payload;
darran	0:55a05330f8cc	434	hlen = IPH_HL(ip) << 2;
darran	0:55a05330f8cc	435	if (IPH_PROTO(ip) >= MAX_SLOTS
darran	0:55a05330f8cc	436	\|\| hlen + sizeof(struct tcp_hdr) > nb->len
darran	0:55a05330f8cc	437	\|\| (hlen += TCPH_OFFSET(((struct tcp_hdr )&((char )ip)[hlen])) << 2)
darran	0:55a05330f8cc	438	> nb->len
darran	0:55a05330f8cc	439	\|\| hlen > MAX_HDR) {
darran	0:55a05330f8cc	440	PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n",
darran	0:55a05330f8cc	441	IPH_PROTO(ip), hlen, nb->len));
darran	0:55a05330f8cc	442	comp->flags \|= VJF_TOSS;
darran	0:55a05330f8cc	443	INCR(vjs_errorin);
darran	0:55a05330f8cc	444	return -1;
darran	0:55a05330f8cc	445	}
darran	0:55a05330f8cc	446	cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)];
darran	0:55a05330f8cc	447	comp->flags &=~ VJF_TOSS;
darran	0:55a05330f8cc	448	IPH_PROTO_SET(ip, IP_PROTO_TCP);
darran	0:55a05330f8cc	449	BCOPY(ip, &cs->cs_ip, hlen);
darran	0:55a05330f8cc	450	cs->cs_hlen = (u_short)hlen;
darran	0:55a05330f8cc	451	INCR(vjs_uncompressedin);
darran	0:55a05330f8cc	452	return 0;
darran	0:55a05330f8cc	453	}
darran	0:55a05330f8cc	454
darran	0:55a05330f8cc	455	/*
darran	0:55a05330f8cc	456	* Uncompress a packet of type TYPE_COMPRESSED_TCP.
darran	0:55a05330f8cc	457	* The packet is composed of a buffer chain and the first buffer
darran	0:55a05330f8cc	458	* must contain an accurate chain length.
darran	0:55a05330f8cc	459	* The first buffer must include the entire compressed TCP/IP header.
darran	0:55a05330f8cc	460	* This procedure replaces the compressed header with the uncompressed
darran	0:55a05330f8cc	461	* header and returns the length of the VJ header.
darran	0:55a05330f8cc	462	*/
darran	0:55a05330f8cc	463	int
darran	0:55a05330f8cc	464	vj_uncompress_tcp(struct pbuf *nb, struct vjcompress comp)
darran	0:55a05330f8cc	465	{
darran	0:55a05330f8cc	466	u_char *cp;
darran	0:55a05330f8cc	467	struct tcp_hdr *th;
darran	0:55a05330f8cc	468	struct cstate *cs;
darran	0:55a05330f8cc	469	u_short *bp;
darran	0:55a05330f8cc	470	struct pbuf n0 = nb;
darran	0:55a05330f8cc	471	u32_t tmp;
darran	0:55a05330f8cc	472	u_int vjlen, hlen, changes;
darran	0:55a05330f8cc	473
darran	0:55a05330f8cc	474	INCR(vjs_compressedin);
darran	0:55a05330f8cc	475	cp = (u_char *)n0->payload;
darran	0:55a05330f8cc	476	changes = *cp++;
darran	0:55a05330f8cc	477	if (changes & NEW_C) {
darran	0:55a05330f8cc	478	/*
darran	0:55a05330f8cc	479	* Make sure the state index is in range, then grab the state.
darran	0:55a05330f8cc	480	* If we have a good state index, clear the 'discard' flag.
darran	0:55a05330f8cc	481	*/
darran	0:55a05330f8cc	482	if (*cp >= MAX_SLOTS) {
darran	0:55a05330f8cc	483	PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp));
darran	0:55a05330f8cc	484	goto bad;
darran	0:55a05330f8cc	485	}
darran	0:55a05330f8cc	486
darran	0:55a05330f8cc	487	comp->flags &=~ VJF_TOSS;
darran	0:55a05330f8cc	488	comp->last_recv = *cp++;
darran	0:55a05330f8cc	489	} else {
darran	0:55a05330f8cc	490	/*
darran	0:55a05330f8cc	491	* this packet has an implicit state index. If we've
darran	0:55a05330f8cc	492	* had a line error since the last time we got an
darran	0:55a05330f8cc	493	* explicit state index, we have to toss the packet.
darran	0:55a05330f8cc	494	*/
darran	0:55a05330f8cc	495	if (comp->flags & VJF_TOSS) {
darran	0:55a05330f8cc	496	PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n"));
darran	0:55a05330f8cc	497	INCR(vjs_tossed);
darran	0:55a05330f8cc	498	return (-1);
darran	0:55a05330f8cc	499	}
darran	0:55a05330f8cc	500	}
darran	0:55a05330f8cc	501	cs = &comp->rstate[comp->last_recv];
darran	0:55a05330f8cc	502	hlen = IPH_HL(&cs->cs_ip) << 2;
darran	0:55a05330f8cc	503	th = (struct tcp_hdr )&((u_char )&cs->cs_ip)[hlen];
darran	0:55a05330f8cc	504	th->chksum = htons((*cp << 8) \| cp[1]);
darran	0:55a05330f8cc	505	cp += 2;
darran	0:55a05330f8cc	506	if (changes & TCP_PUSH_BIT) {
darran	0:55a05330f8cc	507	TCPH_SET_FLAG(th, TCP_PSH);
darran	0:55a05330f8cc	508	} else {
darran	0:55a05330f8cc	509	TCPH_UNSET_FLAG(th, TCP_PSH);
darran	0:55a05330f8cc	510	}
darran	0:55a05330f8cc	511
darran	0:55a05330f8cc	512	switch (changes & SPECIALS_MASK) {
darran	0:55a05330f8cc	513	case SPECIAL_I:
darran	0:55a05330f8cc	514	{
darran	0:55a05330f8cc	515	register u32_t i = ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
darran	0:55a05330f8cc	516	/* some compilers can't nest inline assembler.. */
darran	0:55a05330f8cc	517	tmp = ntohl(th->ackno) + i;
darran	0:55a05330f8cc	518	th->ackno = htonl(tmp);
darran	0:55a05330f8cc	519	tmp = ntohl(th->seqno) + i;
darran	0:55a05330f8cc	520	th->seqno = htonl(tmp);
darran	0:55a05330f8cc	521	}
darran	0:55a05330f8cc	522	break;
darran	0:55a05330f8cc	523
darran	0:55a05330f8cc	524	case SPECIAL_D:
darran	0:55a05330f8cc	525	/* some compilers can't nest inline assembler.. */
darran	0:55a05330f8cc	526	tmp = ntohl(th->seqno) + ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
darran	0:55a05330f8cc	527	th->seqno = htonl(tmp);
darran	0:55a05330f8cc	528	break;
darran	0:55a05330f8cc	529
darran	0:55a05330f8cc	530	default:
darran	0:55a05330f8cc	531	if (changes & NEW_U) {
darran	0:55a05330f8cc	532	TCPH_SET_FLAG(th, TCP_URG);
darran	0:55a05330f8cc	533	DECODEU(th->urgp);
darran	0:55a05330f8cc	534	} else {
darran	0:55a05330f8cc	535	TCPH_UNSET_FLAG(th, TCP_URG);
darran	0:55a05330f8cc	536	}
darran	0:55a05330f8cc	537	if (changes & NEW_W) {
darran	0:55a05330f8cc	538	DECODES(th->wnd);
darran	0:55a05330f8cc	539	}
darran	0:55a05330f8cc	540	if (changes & NEW_A) {
darran	0:55a05330f8cc	541	DECODEL(th->ackno);
darran	0:55a05330f8cc	542	}
darran	0:55a05330f8cc	543	if (changes & NEW_S) {
darran	0:55a05330f8cc	544	DECODEL(th->seqno);
darran	0:55a05330f8cc	545	}
darran	0:55a05330f8cc	546	break;
darran	0:55a05330f8cc	547	}
darran	0:55a05330f8cc	548	if (changes & NEW_I) {
darran	0:55a05330f8cc	549	DECODES(cs->cs_ip._id);
darran	0:55a05330f8cc	550	} else {
darran	0:55a05330f8cc	551	IPH_ID_SET(&cs->cs_ip, ntohs(IPH_ID(&cs->cs_ip)) + 1);
darran	0:55a05330f8cc	552	IPH_ID_SET(&cs->cs_ip, htons(IPH_ID(&cs->cs_ip)));
darran	0:55a05330f8cc	553	}
darran	0:55a05330f8cc	554
darran	0:55a05330f8cc	555	/*
darran	0:55a05330f8cc	556	* At this point, cp points to the first byte of data in the
darran	0:55a05330f8cc	557	* packet. Fill in the IP total length and update the IP
darran	0:55a05330f8cc	558	* header checksum.
darran	0:55a05330f8cc	559	*/
darran	0:55a05330f8cc	560	vjlen = (u_short)(cp - (u_char*)n0->payload);
darran	0:55a05330f8cc	561	if (n0->len < vjlen) {
darran	0:55a05330f8cc	562	/*
darran	0:55a05330f8cc	563	* We must have dropped some characters (crc should detect
darran	0:55a05330f8cc	564	* this but the old slip framing won't)
darran	0:55a05330f8cc	565	*/
darran	0:55a05330f8cc	566	PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n",
darran	0:55a05330f8cc	567	n0->len, vjlen));
darran	0:55a05330f8cc	568	goto bad;
darran	0:55a05330f8cc	569	}
darran	0:55a05330f8cc	570
darran	0:55a05330f8cc	571	#if BYTE_ORDER == LITTLE_ENDIAN
darran	0:55a05330f8cc	572	tmp = n0->tot_len - vjlen + cs->cs_hlen;
darran	0:55a05330f8cc	573	IPH_LEN_SET(&cs->cs_ip, htons((u_short)tmp));
darran	0:55a05330f8cc	574	#else
darran	0:55a05330f8cc	575	IPH_LEN_SET(&cs->cs_ip, htons(n0->tot_len - vjlen + cs->cs_hlen));
darran	0:55a05330f8cc	576	#endif
darran	0:55a05330f8cc	577
darran	0:55a05330f8cc	578	/* recompute the ip header checksum */
darran	0:55a05330f8cc	579	bp = (u_short *) &cs->cs_ip;
darran	0:55a05330f8cc	580	IPH_CHKSUM_SET(&cs->cs_ip, 0);
darran	0:55a05330f8cc	581	for (tmp = 0; hlen > 0; hlen -= 2) {
darran	0:55a05330f8cc	582	tmp += *bp++;
darran	0:55a05330f8cc	583	}
darran	0:55a05330f8cc	584	tmp = (tmp & 0xffff) + (tmp >> 16);
darran	0:55a05330f8cc	585	tmp = (tmp & 0xffff) + (tmp >> 16);
darran	0:55a05330f8cc	586	IPH_CHKSUM_SET(&cs->cs_ip, (u_short)(~tmp));
darran	0:55a05330f8cc	587
darran	0:55a05330f8cc	588	/* Remove the compressed header and prepend the uncompressed header. */
darran	0:55a05330f8cc	589	if(pbuf_header(n0, -((s16_t)(vjlen)))) {
darran	0:55a05330f8cc	590	/* Can we cope with this failing? Just assert for now */
darran	0:55a05330f8cc	591	LWIP_ASSERT("pbuf_header failed\n", 0);
darran	0:55a05330f8cc	592	goto bad;
darran	0:55a05330f8cc	593	}
darran	0:55a05330f8cc	594
darran	0:55a05330f8cc	595	if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) {
darran	0:55a05330f8cc	596	struct pbuf np, q;
darran	0:55a05330f8cc	597	u8_t *bufptr;
darran	0:55a05330f8cc	598
darran	0:55a05330f8cc	599	np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL);
darran	0:55a05330f8cc	600	if(!np) {
darran	0:55a05330f8cc	601	PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n"));
darran	0:55a05330f8cc	602	goto bad;
darran	0:55a05330f8cc	603	}
darran	0:55a05330f8cc	604
darran	0:55a05330f8cc	605	if(pbuf_header(np, -cs->cs_hlen)) {
darran	0:55a05330f8cc	606	/* Can we cope with this failing? Just assert for now */
darran	0:55a05330f8cc	607	LWIP_ASSERT("pbuf_header failed\n", 0);
darran	0:55a05330f8cc	608	goto bad;
darran	0:55a05330f8cc	609	}
darran	0:55a05330f8cc	610
darran	0:55a05330f8cc	611	bufptr = (u8_t*) n0->payload;
darran	0:55a05330f8cc	612	for(q = np; q != NULL; q = q->next) {
darran	0:55a05330f8cc	613	MEMCPY(q->payload, bufptr, q->len);
darran	0:55a05330f8cc	614	bufptr += q->len;
darran	0:55a05330f8cc	615	}
darran	0:55a05330f8cc	616
darran	0:55a05330f8cc	617	if(n0->next) {
darran	0:55a05330f8cc	618	pbuf_chain(np, n0->next);
darran	0:55a05330f8cc	619	pbuf_dechain(n0);
darran	0:55a05330f8cc	620	}
darran	0:55a05330f8cc	621	pbuf_free(n0);
darran	0:55a05330f8cc	622	n0 = np;
darran	0:55a05330f8cc	623	}
darran	0:55a05330f8cc	624
darran	0:55a05330f8cc	625	if(pbuf_header(n0, cs->cs_hlen)) {
darran	0:55a05330f8cc	626	struct pbuf *np;
darran	0:55a05330f8cc	627
darran	0:55a05330f8cc	628	LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE);
darran	0:55a05330f8cc	629	np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL);
darran	0:55a05330f8cc	630	if(!np) {
darran	0:55a05330f8cc	631	PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n"));
darran	0:55a05330f8cc	632	goto bad;
darran	0:55a05330f8cc	633	}
darran	0:55a05330f8cc	634	pbuf_cat(np, n0);
darran	0:55a05330f8cc	635	n0 = np;
darran	0:55a05330f8cc	636	}
darran	0:55a05330f8cc	637	LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen);
darran	0:55a05330f8cc	638	MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen);
darran	0:55a05330f8cc	639
darran	0:55a05330f8cc	640	*nb = n0;
darran	0:55a05330f8cc	641
darran	0:55a05330f8cc	642	return vjlen;
darran	0:55a05330f8cc	643
darran	0:55a05330f8cc	644	bad:
darran	0:55a05330f8cc	645	comp->flags \|= VJF_TOSS;
darran	0:55a05330f8cc	646	INCR(vjs_errorin);
darran	0:55a05330f8cc	647	return (-1);
darran	0:55a05330f8cc	648	}
darran	0:55a05330f8cc	649
darran	0:55a05330f8cc	650	#endif /* VJ_SUPPORT */
darran	0:55a05330f8cc	651
darran	0:55a05330f8cc	652	#endif /* PPP_SUPPORT */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	18 Jun 2010
Imports:	7
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	1
Followers:	1

lwip/netif/ppp/vj.c@1:4218cacaf696, 2010-06-18 (annotated)

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