1 /* 2 * Copyright (c) 1989, 1990, 1991, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22 /* \summary: Compressed Serial Line Internet Protocol printer */ 23 24 #ifdef HAVE_CONFIG_H 25 #include <config.h> 26 #endif 27 28 #include "netdissect-stdinc.h" 29 30 #define ND_LONGJMP_FROM_TCHECK 31 #include "netdissect.h" 32 #include "extract.h" 33 34 #include "ip.h" 35 #include "tcp.h" 36 #include "slcompress.h" 37 38 /* 39 * definitions of the pseudo- link-level header attached to slip 40 * packets grabbed by the packet filter (bpf) traffic monitor. 41 */ 42 #define SLIP_HDRLEN 16 43 44 #define SLX_DIR 0 45 #define SLX_CHDR 1 46 47 #define SLIPDIR_IN 0 48 #define SLIPDIR_OUT 1 49 50 51 static u_int lastlen[2][256]; 52 static u_int lastconn = 255; 53 54 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int); 55 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int); 56 57 void 58 sl_if_print(netdissect_options *ndo, 59 const struct pcap_pkthdr *h, const u_char *p) 60 { 61 u_int length = h->len; 62 const struct ip *ip; 63 64 ndo->ndo_protocol = "slip"; 65 ND_TCHECK_LEN(p, SLIP_HDRLEN); 66 ndo->ndo_ll_hdr_len += SLIP_HDRLEN; 67 68 length -= SLIP_HDRLEN; 69 70 ip = (const struct ip *)(p + SLIP_HDRLEN); 71 72 if (ndo->ndo_eflag) 73 sliplink_print(ndo, p, ip, length); 74 75 switch (IP_V(ip)) { 76 case 4: 77 ip_print(ndo, (const u_char *)ip, length); 78 break; 79 case 6: 80 ip6_print(ndo, (const u_char *)ip, length); 81 break; 82 default: 83 ND_PRINT("ip v%u", IP_V(ip)); 84 } 85 } 86 87 void 88 sl_bsdos_if_print(netdissect_options *ndo, 89 const struct pcap_pkthdr *h, const u_char *p) 90 { 91 u_int length = h->len; 92 const struct ip *ip; 93 94 ndo->ndo_protocol = "slip_bsdos"; 95 ND_TCHECK_LEN(p, SLIP_HDRLEN); 96 ndo->ndo_ll_hdr_len += SLIP_HDRLEN; 97 98 length -= SLIP_HDRLEN; 99 100 ip = (const struct ip *)(p + SLIP_HDRLEN); 101 102 #ifdef notdef 103 if (ndo->ndo_eflag) 104 sliplink_print(ndo, p, ip, length); 105 #endif 106 107 ip_print(ndo, (const u_char *)ip, length); 108 } 109 110 static void 111 sliplink_print(netdissect_options *ndo, 112 const u_char *p, const struct ip *ip, 113 u_int length) 114 { 115 int dir; 116 u_int hlen; 117 118 dir = GET_U_1(p + SLX_DIR); 119 switch (dir) { 120 121 case SLIPDIR_IN: 122 ND_PRINT("I "); 123 break; 124 125 case SLIPDIR_OUT: 126 ND_PRINT("O "); 127 break; 128 129 default: 130 ND_PRINT("Invalid direction %d ", dir); 131 dir = -1; 132 break; 133 } 134 switch (GET_U_1(p + SLX_CHDR) & 0xf0) { 135 136 case TYPE_IP: 137 ND_PRINT("ip %u: ", length + SLIP_HDRLEN); 138 break; 139 140 case TYPE_UNCOMPRESSED_TCP: 141 /* 142 * The connection id is stored in the IP protocol field. 143 * Get it from the link layer since sl_uncompress_tcp() 144 * has restored the IP header copy to IPPROTO_TCP. 145 */ 146 lastconn = GET_U_1(((const struct ip *)(p + SLX_CHDR))->ip_p); 147 ND_PRINT("utcp %u: ", lastconn); 148 if (dir == -1) { 149 /* Direction is bogus, don't use it */ 150 return; 151 } 152 ND_TCHECK_SIZE(ip); 153 hlen = IP_HL(ip); 154 ND_TCHECK_SIZE((const struct tcphdr *)&((const int *)ip)[hlen]); 155 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]); 156 lastlen[dir][lastconn] = length - (hlen << 2); 157 break; 158 159 default: 160 if (dir == -1) { 161 /* Direction is bogus, don't use it */ 162 return; 163 } 164 if (GET_U_1(p + SLX_CHDR) & TYPE_COMPRESSED_TCP) { 165 compressed_sl_print(ndo, p + SLX_CHDR, ip, length, dir); 166 ND_PRINT(": "); 167 } else 168 ND_PRINT("slip-%u!: ", GET_U_1(p + SLX_CHDR)); 169 } 170 } 171 172 static const u_char * 173 print_sl_change(netdissect_options *ndo, 174 const char *str, const u_char *cp) 175 { 176 u_int i; 177 178 if ((i = GET_U_1(cp)) == 0) { 179 cp++; 180 i = GET_BE_U_2(cp); 181 cp += 2; 182 } 183 ND_PRINT(" %s%u", str, i); 184 return (cp); 185 } 186 187 static const u_char * 188 print_sl_winchange(netdissect_options *ndo, 189 const u_char *cp) 190 { 191 int16_t i; 192 193 if ((i = GET_U_1(cp)) == 0) { 194 cp++; 195 i = GET_BE_S_2(cp); 196 cp += 2; 197 } 198 if (i >= 0) 199 ND_PRINT(" W+%d", i); 200 else 201 ND_PRINT(" W%d", i); 202 return (cp); 203 } 204 205 static void 206 compressed_sl_print(netdissect_options *ndo, 207 const u_char *chdr, const struct ip *ip, 208 u_int length, int dir) 209 { 210 const u_char *cp = chdr; 211 u_int flags, hlen; 212 213 flags = GET_U_1(cp); 214 cp++; 215 if (flags & NEW_C) { 216 lastconn = GET_U_1(cp); 217 cp++; 218 ND_PRINT("ctcp %u", lastconn); 219 } else 220 ND_PRINT("ctcp *"); 221 222 /* skip tcp checksum */ 223 cp += 2; 224 225 switch (flags & SPECIALS_MASK) { 226 case SPECIAL_I: 227 ND_PRINT(" *SA+%u", lastlen[dir][lastconn]); 228 break; 229 230 case SPECIAL_D: 231 ND_PRINT(" *S+%u", lastlen[dir][lastconn]); 232 break; 233 234 default: 235 if (flags & NEW_U) 236 cp = print_sl_change(ndo, "U=", cp); 237 if (flags & NEW_W) 238 cp = print_sl_winchange(ndo, cp); 239 if (flags & NEW_A) 240 cp = print_sl_change(ndo, "A+", cp); 241 if (flags & NEW_S) 242 cp = print_sl_change(ndo, "S+", cp); 243 break; 244 } 245 if (flags & NEW_I) 246 cp = print_sl_change(ndo, "I+", cp); 247 248 /* 249 * 'hlen' is the length of the uncompressed TCP/IP header (in words). 250 * 'cp - chdr' is the length of the compressed header. 251 * 'length - hlen' is the amount of data in the packet. 252 */ 253 ND_TCHECK_SIZE(ip); 254 hlen = IP_HL(ip); 255 ND_TCHECK_SIZE((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 256 hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 257 lastlen[dir][lastconn] = length - (hlen << 2); 258 ND_PRINT(" %u (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)); 259 } 260