diff options
Diffstat (limited to 'c/src/libnetworking/pppd/modem_example/pppcompress.c')
| -rw-r--r-- | c/src/libnetworking/pppd/modem_example/pppcompress.c | 593 |
1 files changed, 0 insertions, 593 deletions
diff --git a/c/src/libnetworking/pppd/modem_example/pppcompress.c b/c/src/libnetworking/pppd/modem_example/pppcompress.c deleted file mode 100644 index a7d2734c8d..0000000000 --- a/c/src/libnetworking/pppd/modem_example/pppcompress.c +++ /dev/null @@ -1,593 +0,0 @@ -/*- - * Copyright (c) 1989 The Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * @(#)slcompress.c 7.7 (Berkeley) 5/7/91 - */ - -/* - * Routines to compress and uncompess tcp packets (for transmission - * over low speed serial lines. - * - * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: - * - Initial distribution. - * - * $Id$ - */ - -#include <sys/types.h> -#include <sys/param.h> -#include <sys/systm.h> -#include <sys/mbuf.h> -#include <sys/socket.h> -#include <sys/socketvar.h> - -#include <netinet/in.h> -#include <netinet/in_systm.h> -#include <netinet/ip.h> -#include <netinet/tcp.h> - -#include <net/pppcompress.h> - -#ifndef SL_NO_STATS -#define INCR(counter) ++comp->counter; -#else -#define INCR(counter) -#endif - -#define BCMP(p1, p2, n) bcmp((char *)(p1), (char *)(p2), (int)(n)) -#define BCOPY(p1, p2, n) bcopy((char *)(p1), (char *)(p2), (int)(n)) -#ifndef KERNEL -#define ovbcopy bcopy -#endif - -void -vj_compress_init(comp, max_state) - struct vjcompress *comp; - int max_state; -{ - register u_int i; - register struct cstate *tstate = comp->tstate; - - if ((unsigned) max_state > MAX_STATES - 1) - max_state = MAX_STATES - 1; - bzero((char *)comp, 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 long, 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_long)*cp++); \ - } \ -} - -#define DECODES(f) { \ - if (*cp == 0) {\ - (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ - cp += 3; \ - } else { \ - (f) = htons(ntohs(f) + (u_long)*cp++); \ - } \ -} - -#define DECODEU(f) { \ - if (*cp == 0) {\ - (f) = htons((cp[1] << 8) | cp[2]); \ - cp += 3; \ - } else { \ - (f) = htons((u_long)*cp++); \ - } \ -} - -u_int -vj_compress_tcp(m, ip, comp, compress_cid) - struct mbuf *m; - register struct ip *ip; - struct vjcompress *comp; - 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) - return (TYPE_IP); - - th = (struct tcphdr *)&((int *)ip)[hlen]; - if ((th->th_flags & (TH_SYN|TH_FIN|TH_RST|TH_ACK)) != TH_ACK) - 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. - */ - INCR(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; - INCR(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. - */ - INCR(sls_misses) - comp->last_cs = lcs; - hlen += th->th_off; - hlen <<= 2; - 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 (((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] || - th->th_off != oth->th_off || - (deltaS > 5 && - BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || - (th->th_off > 5 && - BCMP(th + 1, oth + 1, (th->th_off - 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; - - if (deltaS = (u_short)(ntohs(th->th_win) - ntohs(oth->th_win))) { - ENCODE(deltaS); - changes |= NEW_W; - } - - if (deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack)) { - if (deltaA > 0xffff) - goto uncompressed; - ENCODE(deltaA); - changes |= NEW_A; - } - - if (deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq)) { - 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); - BCOPY(ip, &cs->cs_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; - if (compress_cid == 0 || comp->last_xmit != cs->cs_id) { - comp->last_xmit = cs->cs_id; - hlen -= deltaS + 4; - cp += hlen; - *cp++ = changes | NEW_C; - *cp++ = cs->cs_id; - } else { - hlen -= deltaS + 3; - cp += hlen; - *cp++ = changes; - } - m->m_len -= hlen; - m->m_data += hlen; - *cp++ = deltaA >> 8; - *cp++ = deltaA; - BCOPY(new_seq, cp, deltaS); - INCR(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: - BCOPY(ip, &cs->cs_ip, hlen); - ip->ip_p = cs->cs_id; - comp->last_xmit = cs->cs_id; - return (TYPE_UNCOMPRESSED_TCP); -} - - -int -vj_uncompress_tcp(bufp, len, type, comp) - u_char **bufp; - int len; - u_int type; - struct vjcompress *comp; -{ - u_char *hdr, *cp; - int hlen, vjlen; - - cp = bufp? *bufp: NULL; - vjlen = vj_uncompress_tcp_core(cp, len, len, type, comp, &hdr, &hlen); - if (vjlen < 0) - return (0); /* error */ - if (vjlen == 0) - return (len); /* was uncompressed already */ - - cp += vjlen; - len -= vjlen; - - /* - * At this point, cp points to the first byte of data in the - * packet. If we're not aligned on a 4-byte boundary, copy the - * data down so the ip & tcp headers will be aligned. Then 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). - */ - if ((int)cp & 3) { - if (len > 0) - (void) ovbcopy(cp, (caddr_t)((int)cp &~ 3), len); - cp = (u_char *)((int)cp &~ 3); - } - cp -= hlen; - len += hlen; - BCOPY(hdr, cp, hlen); - - *bufp = cp; - return (len); -} - -/* - * Uncompress a packet of total length total_len. The first buflen - * bytes are at buf; this must include the entire (compressed or - * uncompressed) TCP/IP header. This procedure returns the length - * of the VJ header, with a pointer to the uncompressed IP header - * in *hdrp and its length in *hlenp. - */ -int -vj_uncompress_tcp_core(buf, buflen, total_len, type, comp, hdrp, hlenp) - u_char *buf; - int buflen, total_len; - u_int type; - struct vjcompress *comp; - u_char **hdrp; - u_int *hlenp; -{ - register u_char *cp; - register u_int hlen, changes; - register struct tcphdr *th; - register struct cstate *cs; - register struct ip *ip; - register u_short *bp; - register u_int vjlen; - - switch (type) { - - case TYPE_UNCOMPRESSED_TCP: - ip = (struct ip *) buf; - if (ip->ip_p >= MAX_STATES) - 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) > buflen) - goto bad; - hlen += ((struct tcphdr *)&((char *)ip)[hlen])->th_off << 2; - if (hlen > MAX_HDR || hlen > buflen) - goto bad; - BCOPY(ip, &cs->cs_ip, hlen); - cs->cs_hlen = hlen; - INCR(sls_uncompressedin) - *hdrp = (u_char *) &cs->cs_ip; - *hlenp = hlen; - return (0); - - default: - goto bad; - - case TYPE_COMPRESSED_TCP: - break; - } - /* We've got a compressed packet. */ - INCR(sls_compressedin) - cp = buf; - changes = *cp++; - 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_STATES) - 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) { - INCR(sls_tossed) - return (-1); - } - } - 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) - 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); - - /* - * At this point, cp points to the first byte of data in the - * packet. Fill in the IP total length and update the IP - * header checksum. - */ - vjlen = cp - buf; - buflen -= vjlen; - if (buflen < 0) - /* we must have dropped some characters (crc should detect - * this but the old slip framing won't) */ - goto bad; - - total_len += cs->cs_hlen - vjlen; - cs->cs_ip.ip_len = htons(total_len); - - /* recompute the ip header checksum */ - bp = (u_short *) &cs->cs_ip; - cs->cs_ip.ip_sum = 0; - 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; - - *hdrp = (u_char *) &cs->cs_ip; - *hlenp = cs->cs_hlen; - return vjlen; - -bad: - comp->flags |= SLF_TOSS; - INCR(sls_errorin) - return (-1); -} |