freebsd-dev/usr.sbin/ppp/slcompress.c
Brian Somers 30949fd4b5 o Add ipv6 support, abstracting most NCP addresses into opaque
structures (well, they're treated as opaque).

  It's now possible to manage IPv6 interface addresses and routing
  table entries and to filter IPV6 traffic whether encapsulated or
  not.

  IPV6CP support is crude for now, and hasn't been tested against
  any other implementations.

  RADIUS and IPv6 are independent of eachother for now.

  ppp.linkup/ppp.linkdown aren't currently used by IPV6CP

o Understand all protocols(5) in filter rules rather than only a select
  few.

o Allow a mask specification for the ``delete'' command.  It's now
  possible to specifically delete one of two conflicting routes.

o When creating and deleting proxy arp entries, do it for all IPv4
  interface addresses rather than doing it just for the ``current''
  peer address.

o When iface-alias isn't in effect, don't blow away manually (via ``iface
  add'') added interface addresses.

o When listening on a tcp server (diagnostic) socket, bind so that a
  tcp46 socket is created -- allowing both IPv4 and IPv6 connections.

o When displaying ICMP traffic, don't display the icmp type twice.
  When display traffic, display at least some information about unrecognised
  traffic.

o Bump version

Inspired after filtering work by: Makoto MATSUSHITA <matusita@jp.FreeBSD.org>
2001-08-14 16:05:52 +00:00

590 lines
16 KiB
C

/*
* Routines to compress and uncompess tcp packets (for transmission
* over low speed serial lines.
*
* Copyright (c) 1989 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $FreeBSD$
*
* Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
* - Initial distribution.
*/
#include <sys/param.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netinet/ip.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <string.h>
#include <termios.h>
#include "layer.h"
#include "defs.h"
#include "command.h"
#include "mbuf.h"
#include "log.h"
#include "slcompress.h"
#include "descriptor.h"
#include "prompt.h"
#include "timer.h"
#include "fsm.h"
#include "throughput.h"
#include "iplist.h"
#include "lqr.h"
#include "hdlc.h"
#include "ncpaddr.h"
#include "ip.h"
#include "ipcp.h"
#include "filter.h"
#include "lcp.h"
#include "ccp.h"
#include "link.h"
#include "mp.h"
#ifndef NORADIUS
#include "radius.h"
#endif
#include "ipv6cp.h"
#include "ncp.h"
#include "bundle.h"
void
sl_compress_init(struct slcompress *comp, int max_state)
{
register u_int i;
register struct cstate *tstate = comp->tstate;
memset(comp, '\0', sizeof *comp);
for (i = max_state; i > 0; --i) {
tstate[i].cs_id = i;
tstate[i].cs_next = &tstate[i - 1];
}
tstate[0].cs_next = &tstate[max_state];
tstate[0].cs_id = 0;
comp->last_cs = &tstate[0];
comp->last_recv = 255;
comp->last_xmit = 255;
comp->flags = SLF_TOSS;
}
/* ENCODE encodes a number that is known to be non-zero. ENCODEZ
* checks for zero (since zero has to be encoded in the 32-bit, 3 byte
* form).
*/
#define ENCODE(n) { \
if ((u_short)(n) >= 256) { \
*cp++ = 0; \
cp[1] = (n); \
cp[0] = (n) >> 8; \
cp += 2; \
} else { \
*cp++ = (n); \
} \
}
#define ENCODEZ(n) { \
if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \
*cp++ = 0; \
cp[1] = (n); \
cp[0] = (n) >> 8; \
cp += 2; \
} else { \
*cp++ = (n); \
} \
}
#define DECODEL(f) { \
if (*cp == 0) {\
(f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \
cp += 3; \
} else { \
(f) = htonl(ntohl(f) + (u_int32_t)*cp++); \
} \
}
#define DECODES(f) { \
if (*cp == 0) {\
(f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \
cp += 3; \
} else { \
(f) = htons(ntohs(f) + (u_int32_t)*cp++); \
} \
}
#define DECODEU(f) { \
if (*cp == 0) {\
(f) = htons((cp[1] << 8) | cp[2]); \
cp += 3; \
} else { \
(f) = htons((u_int32_t)*cp++); \
} \
}
u_char
sl_compress_tcp(struct mbuf * m,
struct ip * ip,
struct slcompress *comp,
struct slstat *slstat,
int compress_cid)
{
register struct cstate *cs = comp->last_cs->cs_next;
register u_int hlen = ip->ip_hl;
register struct tcphdr *oth;
register struct tcphdr *th;
register u_int deltaS, deltaA;
register u_int changes = 0;
u_char new_seq[16];
register u_char *cp = new_seq;
/*
* Bail if this is an IP fragment or if the TCP packet isn't `compressible'
* (i.e., ACK isn't set or some other control bit is set). (We assume that
* the caller has already made sure the packet is IP proto TCP).
*/
if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) {
log_Printf(LogDEBUG, "??? 1 ip_off = %x, m_len = %lu\n",
ip->ip_off, (unsigned long)m->m_len);
log_DumpBp(LogDEBUG, "", m);
return (TYPE_IP);
}
th = (struct tcphdr *) & ((int *) ip)[hlen];
if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) {
log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags);
log_DumpBp(LogDEBUG, "", m);
return (TYPE_IP);
}
/*
* Packet is compressible -- we're going to send either a COMPRESSED_TCP or
* UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the
* connection state. Special case the most recently used connection since
* it's most likely to be used again & we don't have to do any reordering
* if it's used.
*/
slstat->sls_packets++;
if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr ||
ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr ||
*(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) {
/*
* Wasn't the first -- search for it.
*
* States are kept in a circularly linked list with last_cs pointing to the
* end of the list. The list is kept in lru order by moving a state to
* the head of the list whenever it is referenced. Since the list is
* short and, empirically, the connection we want is almost always near
* the front, we locate states via linear search. If we don't find a
* state for the datagram, the oldest state is (re-)used.
*/
register struct cstate *lcs;
register struct cstate *lastcs = comp->last_cs;
do {
lcs = cs;
cs = cs->cs_next;
slstat->sls_searches++;
if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr
&& ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr
&& *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl])
goto found;
} while (cs != lastcs);
/*
* Didn't find it -- re-use oldest cstate. Send an uncompressed packet
* that tells the other side what connection number we're using for this
* conversation. Note that since the state list is circular, the oldest
* state points to the newest and we only need to set last_cs to update
* the lru linkage.
*/
slstat->sls_misses++;
comp->last_cs = lcs;
#define THOFFSET(th) (th->th_off)
hlen += th->th_off;
hlen <<= 2;
if (hlen > m->m_len)
return (TYPE_IP);
goto uncompressed;
found:
/*
* Found it -- move to the front on the connection list.
*/
if (cs == lastcs)
comp->last_cs = lcs;
else {
lcs->cs_next = cs->cs_next;
cs->cs_next = lastcs->cs_next;
lastcs->cs_next = cs;
}
}
/*
* Make sure that only what we expect to change changed. The first line of
* the `if' checks the IP protocol version, header length & type of
* service. The 2nd line checks the "Don't fragment" bit. The 3rd line
* checks the time-to-live and protocol (the protocol check is unnecessary
* but costless). The 4th line checks the TCP header length. The 5th line
* checks IP options, if any. The 6th line checks TCP options, if any. If
* any of these things are different between the previous & current
* datagram, we send the current datagram `uncompressed'.
*/
oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen];
deltaS = hlen;
hlen += th->th_off;
hlen <<= 2;
if (hlen > m->m_len)
return (TYPE_IP);
if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] ||
((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] ||
((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] ||
THOFFSET(th) != THOFFSET(oth) ||
(deltaS > 5 &&
memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) ||
(THOFFSET(th) > 5 &&
memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) {
goto uncompressed;
}
/*
* Figure out which of the changing fields changed. The receiver expects
* changes in the order: urgent, window, ack, seq (the order minimizes the
* number of temporaries needed in this section of code).
*/
if (th->th_flags & TH_URG) {
deltaS = ntohs(th->th_urp);
ENCODEZ(deltaS);
changes |= NEW_U;
} else if (th->th_urp != oth->th_urp) {
/*
* argh! URG not set but urp changed -- a sensible implementation should
* never do this but RFC793 doesn't prohibit the change so we have to
* deal with it.
*/
goto uncompressed;
}
deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win));
if (deltaS) {
ENCODE(deltaS);
changes |= NEW_W;
}
deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack);
if (deltaA) {
if (deltaA > 0xffff) {
goto uncompressed;
}
ENCODE(deltaA);
changes |= NEW_A;
}
deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq);
if (deltaS) {
if (deltaS > 0xffff) {
goto uncompressed;
}
ENCODE(deltaS);
changes |= NEW_S;
}
switch (changes) {
case 0:
/*
* Nothing changed. If this packet contains data and the last one didn't,
* this is probably a data packet following an ack (normal on an
* interactive connection) and we send it compressed. Otherwise it's
* probably a retransmit, retransmitted ack or window probe. Send it
* uncompressed in case the other side missed the compressed version.
*/
if (ip->ip_len != cs->cs_ip.ip_len &&
ntohs(cs->cs_ip.ip_len) == hlen)
break;
/* (fall through) */
case SPECIAL_I:
case SPECIAL_D:
/*
* actual changes match one of our special case encodings -- send packet
* uncompressed.
*/
goto uncompressed;
case NEW_S | NEW_A:
if (deltaS == deltaA &&
deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
/* special case for echoed terminal traffic */
changes = SPECIAL_I;
cp = new_seq;
}
break;
case NEW_S:
if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) {
/* special case for data xfer */
changes = SPECIAL_D;
cp = new_seq;
}
break;
}
deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id);
if (deltaS != 1) {
ENCODEZ(deltaS);
changes |= NEW_I;
}
if (th->th_flags & TH_PUSH)
changes |= TCP_PUSH_BIT;
/*
* Grab the cksum before we overwrite it below. Then update our state with
* this packet's header.
*/
deltaA = ntohs(th->th_sum);
memcpy(&cs->cs_ip, ip, hlen);
/*
* We want to use the original packet as our compressed packet. (cp -
* new_seq) is the number of bytes we need for compressed sequence numbers.
* In addition we need one byte for the change mask, one for the connection
* id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header
* are needed. hlen is how many bytes of the original packet to toss so
* subtract the two to get the new packet size.
*/
deltaS = cp - new_seq;
cp = (u_char *) ip;
/*
* Since fastq traffic can jump ahead of the background traffic, we don't
* know what order packets will go on the line. In this case, we always
* send a "new" connection id so the receiver state stays synchronized.
*/
if (comp->last_xmit == cs->cs_id && compress_cid) {
hlen -= deltaS + 3;
cp += hlen;
*cp++ = changes;
} else {
comp->last_xmit = cs->cs_id;
hlen -= deltaS + 4;
cp += hlen;
*cp++ = changes | NEW_C;
*cp++ = cs->cs_id;
}
m->m_len -= hlen;
m->m_offset += hlen;
*cp++ = deltaA >> 8;
*cp++ = deltaA;
memcpy(cp, new_seq, deltaS);
slstat->sls_compressed++;
return (TYPE_COMPRESSED_TCP);
/*
* Update connection state cs & send uncompressed packet ('uncompressed'
* means a regular ip/tcp packet but with the 'conversation id' we hope to
* use on future compressed packets in the protocol field).
*/
uncompressed:
memcpy(&cs->cs_ip, ip, hlen);
ip->ip_p = cs->cs_id;
comp->last_xmit = cs->cs_id;
return (TYPE_UNCOMPRESSED_TCP);
}
int
sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp,
struct slstat *slstat, int max_state)
{
register u_char *cp;
register u_int hlen, changes;
register struct tcphdr *th;
register struct cstate *cs;
register struct ip *ip;
u_short *bp;
switch (type) {
case TYPE_UNCOMPRESSED_TCP:
ip = (struct ip *) * bufp;
if (ip->ip_p > max_state)
goto bad;
cs = &comp->rstate[comp->last_recv = ip->ip_p];
comp->flags &= ~SLF_TOSS;
ip->ip_p = IPPROTO_TCP;
/*
* Calculate the size of the TCP/IP header and make sure that we don't
* overflow the space we have available for it.
*/
hlen = ip->ip_hl << 2;
if (hlen + sizeof(struct tcphdr) > len)
goto bad;
th = (struct tcphdr *) & ((char *) ip)[hlen];
hlen += THOFFSET(th) << 2;
if (hlen > MAX_HDR)
goto bad;
memcpy(&cs->cs_ip, ip, hlen);
cs->cs_hlen = hlen;
slstat->sls_uncompressedin++;
return (len);
default:
goto bad;
case TYPE_COMPRESSED_TCP:
break;
}
/* We've got a compressed packet. */
slstat->sls_compressedin++;
cp = *bufp;
changes = *cp++;
log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes);
if (changes & NEW_C) {
/*
* Make sure the state index is in range, then grab the state. If we have
* a good state index, clear the 'discard' flag.
*/
if (*cp > max_state || comp->last_recv == 255)
goto bad;
comp->flags &= ~SLF_TOSS;
comp->last_recv = *cp++;
} else {
/*
* this packet has an implicit state index. If we've had a line error
* since the last time we got an explicit state index, we have to toss
* the packet.
*/
if (comp->flags & SLF_TOSS) {
slstat->sls_tossed++;
return (0);
}
}
cs = &comp->rstate[comp->last_recv];
hlen = cs->cs_ip.ip_hl << 2;
th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen];
th->th_sum = htons((*cp << 8) | cp[1]);
cp += 2;
if (changes & TCP_PUSH_BIT)
th->th_flags |= TH_PUSH;
else
th->th_flags &= ~TH_PUSH;
switch (changes & SPECIALS_MASK) {
case SPECIAL_I:
{
register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen;
th->th_ack = htonl(ntohl(th->th_ack) + i);
th->th_seq = htonl(ntohl(th->th_seq) + i);
}
break;
case SPECIAL_D:
th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len)
- cs->cs_hlen);
break;
default:
if (changes & NEW_U) {
th->th_flags |= TH_URG;
DECODEU(th->th_urp)
} else
th->th_flags &= ~TH_URG;
if (changes & NEW_W)
DECODES(th->th_win)
if (changes & NEW_A)
DECODEL(th->th_ack)
if (changes & NEW_S) {
log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n",
*cp, cp[1], cp[2]);
DECODEL(th->th_seq)
}
break;
}
if (changes & NEW_I) {
DECODES(cs->cs_ip.ip_id)
} else
cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1);
log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n",
cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq));
/*
* At this point, cp points to the first byte of data in the packet.
* Back up cp by the tcp/ip header length to make room for the
* reconstructed header (we assume the packet we were handed has enough
* space to prepend 128 bytes of header). Adjust the length to account
* for the new header & fill in the IP total length.
*/
len -= (cp - *bufp);
if (len < 0)
/*
* we must have dropped some characters (crc should detect this but the
* old slip framing won't)
*/
goto bad;
*bufp = cp - cs->cs_hlen;
len += cs->cs_hlen;
cs->cs_ip.ip_len = htons(len);
/* recompute the ip header checksum */
cs->cs_ip.ip_sum = 0;
bp = (u_short *)&cs->cs_ip;
for (changes = 0; hlen > 0; hlen -= 2)
changes += *bp++;
changes = (changes & 0xffff) + (changes >> 16);
changes = (changes & 0xffff) + (changes >> 16);
cs->cs_ip.ip_sum = ~changes;
/* And copy the result into our buffer */
memcpy(*bufp, &cs->cs_ip, cs->cs_hlen);
return (len);
bad:
comp->flags |= SLF_TOSS;
slstat->sls_errorin++;
return (0);
}
int
sl_Show(struct cmdargs const *arg)
{
prompt_Printf(arg->prompt, "VJ compression statistics:\n");
prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)",
arg->bundle->ncp.ipcp.vj.slstat.sls_compressed,
arg->bundle->ncp.ipcp.vj.slstat.sls_packets);
prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n",
arg->bundle->ncp.ipcp.vj.slstat.sls_misses,
arg->bundle->ncp.ipcp.vj.slstat.sls_searches);
prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)",
arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin,
arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin);
prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n",
arg->bundle->ncp.ipcp.vj.slstat.sls_errorin,
arg->bundle->ncp.ipcp.vj.slstat.sls_tossed);
return 0;
}