| 0,0 → 1,175 |
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| /*!\file net/slcompre.h |
| * SLIP/PPP compression. |
| */ |
| |
| /* $NetBSD: slcompress.h,v 1.11 1997/05/17 21:12:11 christos Exp $ */ |
| /* Id: slcompress.h,v 1.4 1994/09/21 06:50:08 paulus Exp */ |
| |
| /* |
| * Copyright (c) 1989, 1993 |
| * 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.h 8.1 (Berkeley) 6/10/93 |
| */ |
| |
| /* |
| * Definitions for tcp compression routines. |
| * |
| * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: |
| * - Initial distribution. |
| */ |
| |
| #ifndef __NET_SLCOMPRESS_H |
| #define __NET_SLCOMPRESS_H |
| |
| #ifndef MLEN |
| #define MLEN 128 |
| #endif |
| |
| #define MAX_STATES 16 /* must be > 2 and < 256 */ |
| #define MAX_HDR MLEN /* XXX 4bsd-ism: should really be 128 */ |
| |
| /* |
| * Compressed packet format: |
| * |
| * The first octet contains the packet type (top 3 bits), TCP |
| * 'push' bit, and flags that indicate which of the 4 TCP sequence |
| * numbers have changed (bottom 5 bits). The next octet is a |
| * conversation number that associates a saved IP/TCP header with |
| * the compressed packet. The next two octets are the TCP checksum |
| * from the original datagram. The next 0 to 15 octets are |
| * sequence number changes, one change per bit set in the header |
| * (there may be no changes and there are two special cases where |
| * the receiver implicitly knows what changed -- see below). |
| * |
| * There are 5 numbers which can change (they are always inserted |
| * in the following order): TCP urgent pointer, window, |
| * acknowlegement, sequence number and IP ID. (The urgent pointer |
| * is different from the others in that its value is sent, not the |
| * change in value.) Since typical use of SLIP links is biased |
| * toward small packets (see comments on MTU/MSS below), changes |
| * use a variable length coding with one octet for numbers in the |
| * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the |
| * range 256 - 65535 or 0. (If the change in sequence number or |
| * ack is more than 65535, an uncompressed packet is sent.) |
| */ |
| |
| /* |
| * Packet types (must not conflict with IP protocol version) |
| * |
| * The top nibble of the first octet is the packet type. There are |
| * three possible types: IP (not proto TCP or tcp with one of the |
| * control flags set); uncompressed TCP (a normal IP/TCP packet but |
| * with the 8-bit protocol field replaced by an 8-bit connection id -- |
| * this type of packet syncs the sender & receiver); and compressed |
| * TCP (described above). |
| * |
| * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and |
| * is logically part of the 4-bit "changes" field that follows. Top |
| * three bits are actual packet type. For backward compatibility |
| * and in the interest of conserving bits, numbers are chosen so the |
| * IP protocol version number (4) which normally appears in this nibble |
| * means "IP packet". |
| */ |
| |
| /* packet types */ |
| #define TYPE_IP 0x40 |
| #define TYPE_UNCOMPRESSED_TCP 0x70 |
| #define TYPE_COMPRESSED_TCP 0x80 |
| #define TYPE_ERROR 0x00 |
| |
| /* Bits in first octet of compressed packet */ |
| #define NEW_C 0x40 /* flag bits for what changed in a packet */ |
| #define NEW_I 0x20 |
| #define NEW_S 0x08 |
| #define NEW_A 0x04 |
| #define NEW_W 0x02 |
| #define NEW_U 0x01 |
| |
| /* reserved, special-case values of above */ |
| #define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */ |
| #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */ |
| #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U) |
| |
| #define TCP_PUSH_BIT 0x10 |
| |
| |
| /* |
| * "state" data for each active tcp conversation on the wire. This is |
| * basically a copy of the entire IP/TCP header from the last packet |
| * we saw from the conversation together with a small identifier |
| * the transmit & receive ends of the line use to locate saved header. |
| */ |
| struct cstate { |
| struct cstate *cs_next; /* next most recently used cstate (xmit only) */ |
| u_int16_t cs_hlen; /* size of hdr (receive only) */ |
| u_char cs_id; /* connection # associated with this state */ |
| u_char cs_filler; |
| union { |
| char csu_hdr[MAX_HDR]; |
| struct ip csu_ip; /* ip/tcp hdr from most recent packet */ |
| } slcs_u; |
| }; |
| #define cs_ip slcs_u.csu_ip |
| #define cs_hdr slcs_u.csu_hdr |
| |
| /* |
| * all the state data for one serial line (we need one of these |
| * per line). |
| */ |
| struct slcompress { |
| struct cstate *last_cs; /* most recently used tstate */ |
| u_char last_recv; /* last rcvd conn. id */ |
| u_char last_xmit; /* last sent conn. id */ |
| u_int16_t flags; |
| #ifndef SL_NO_STATS |
| int sls_packets; /* outbound packets */ |
| int sls_compressed; /* outbound compressed packets */ |
| int sls_searches; /* searches for connection state */ |
| int sls_misses; /* times couldn't find conn. state */ |
| int sls_uncompressedin; /* inbound uncompressed packets */ |
| int sls_compressedin; /* inbound compressed packets */ |
| int sls_errorin; /* inbound unknown type packets */ |
| int sls_tossed; /* inbound packets tossed because of error */ |
| #endif |
| struct cstate tstate[MAX_STATES]; /* xmit connection states */ |
| struct cstate rstate[MAX_STATES]; /* receive connection states */ |
| }; |
| /* flag values */ |
| #define SLF_TOSS 1 /* tossing rcvd frames because of input err */ |
| |
| void sl_compress_init (struct slcompress *); |
| void sl_compress_setup (struct slcompress *, int); |
| u_int sl_compress_tcp (struct mbuf *, struct ip *, struct slcompress *, int); |
| int sl_uncompress_tcp (u_char **, int, u_int, struct slcompress *); |
| int sl_uncompress_tcp_core (u_char *, int, int, u_int, struct slcompress *, u_char **, u_int *); |
| |
| #endif |