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 #include "netdissect.h" 31 #include "extract.h" 32 33 #include "ip.h" 34 #include "tcp.h" 35 #include "slcompress.h" 36 37 /* 38 * definitions of the pseudo- link-level header attached to slip 39 * packets grabbed by the packet filter (bpf) traffic monitor. 40 */ 41 #define SLIP_HDRLEN 16 42 43 #define SLX_DIR 0 44 #define SLX_CHDR 1 45 #define CHDR_LEN 15 46 47 #define SLIPDIR_IN 0 48 #define SLIPDIR_OUT 1 49 50 static const char tstr[] = "[|slip]"; 51 52 static u_int lastlen[2][256]; 53 static u_int lastconn = 255; 54 55 static int sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int); 56 static int compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int); 57 58 u_int 59 sl_if_print(netdissect_options *ndo, 60 const struct pcap_pkthdr *h, const u_char *p) 61 { 62 register u_int caplen = h->caplen; 63 register u_int length = h->len; 64 register const struct ip *ip; 65 66 if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) { 67 ND_PRINT((ndo, "%s", tstr)); 68 return (caplen); 69 } 70 71 caplen -= SLIP_HDRLEN; 72 length -= SLIP_HDRLEN; 73 74 ip = (const struct ip *)(p + SLIP_HDRLEN); 75 76 if (ndo->ndo_eflag) 77 if (sliplink_print(ndo, p, ip, length) == -1) { 78 ND_PRINT((ndo, "%s", tstr)); 79 return (caplen + SLIP_HDRLEN); 80 } 81 82 if (caplen < 1 || length < 1) { 83 ND_PRINT((ndo, "%s", tstr)); 84 return (caplen + SLIP_HDRLEN); 85 } 86 87 switch (IP_V(ip)) { 88 case 4: 89 ip_print(ndo, (const u_char *)ip, length); 90 break; 91 case 6: 92 ip6_print(ndo, (const u_char *)ip, length); 93 break; 94 default: 95 ND_PRINT((ndo, "ip v%d", IP_V(ip))); 96 } 97 98 return (SLIP_HDRLEN); 99 } 100 101 u_int 102 sl_bsdos_if_print(netdissect_options *ndo, 103 const struct pcap_pkthdr *h, const u_char *p) 104 { 105 register u_int caplen = h->caplen; 106 register u_int length = h->len; 107 register const struct ip *ip; 108 109 if (caplen < SLIP_HDRLEN) { 110 ND_PRINT((ndo, "%s", tstr)); 111 return (caplen); 112 } 113 114 length -= SLIP_HDRLEN; 115 116 ip = (const struct ip *)(p + SLIP_HDRLEN); 117 118 #ifdef notdef 119 if (ndo->ndo_eflag) 120 sliplink_print(ndo, p, ip, length); 121 #endif 122 123 ip_print(ndo, (const u_char *)ip, length); 124 125 return (SLIP_HDRLEN); 126 } 127 128 static int 129 sliplink_print(netdissect_options *ndo, 130 register const u_char *p, register const struct ip *ip, 131 register u_int length) 132 { 133 int dir; 134 u_int hlen; 135 136 dir = p[SLX_DIR]; 137 switch (dir) { 138 139 case SLIPDIR_IN: 140 ND_PRINT((ndo, "I ")); 141 break; 142 143 case SLIPDIR_OUT: 144 ND_PRINT((ndo, "O ")); 145 break; 146 147 default: 148 ND_PRINT((ndo, "Invalid direction %d ", dir)); 149 dir = -1; 150 break; 151 } 152 if (ndo->ndo_nflag) { 153 /* XXX just dump the header */ 154 register int i; 155 156 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i) 157 ND_PRINT((ndo, "%02x.", p[i])); 158 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1])); 159 return 0; 160 } 161 switch (p[SLX_CHDR] & 0xf0) { 162 163 case TYPE_IP: 164 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN)); 165 break; 166 167 case TYPE_UNCOMPRESSED_TCP: 168 /* 169 * The connection id is stored in the IP protocol field. 170 * Get it from the link layer since sl_uncompress_tcp() 171 * has restored the IP header copy to IPPROTO_TCP. 172 */ 173 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p; 174 ND_PRINT((ndo, "utcp %d: ", lastconn)); 175 if (dir == -1) { 176 /* Direction is bogus, don't use it */ 177 return 0; 178 } 179 ND_TCHECK(*ip); 180 hlen = IP_HL(ip); 181 ND_TCHECK(*((const struct tcphdr *)&((const int *)ip)[hlen])); 182 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]); 183 lastlen[dir][lastconn] = length - (hlen << 2); 184 break; 185 186 default: 187 if (dir == -1) { 188 /* Direction is bogus, don't use it */ 189 return 0; 190 } 191 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) { 192 if (compressed_sl_print(ndo, &p[SLX_CHDR], ip, 193 length, dir) == -1) 194 goto trunc; 195 ND_PRINT((ndo, ": ")); 196 } else 197 ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR])); 198 } 199 return 0; 200 trunc: 201 return -1; 202 } 203 204 static const u_char * 205 print_sl_change(netdissect_options *ndo, 206 const char *str, register const u_char *cp) 207 { 208 register u_int i; 209 210 if ((i = *cp++) == 0) { 211 i = EXTRACT_16BITS(cp); 212 cp += 2; 213 } 214 ND_PRINT((ndo, " %s%d", str, i)); 215 return (cp); 216 } 217 218 static const u_char * 219 print_sl_winchange(netdissect_options *ndo, 220 register const u_char *cp) 221 { 222 register short i; 223 224 if ((i = *cp++) == 0) { 225 i = EXTRACT_16BITS(cp); 226 cp += 2; 227 } 228 if (i >= 0) 229 ND_PRINT((ndo, " W+%d", i)); 230 else 231 ND_PRINT((ndo, " W%d", i)); 232 return (cp); 233 } 234 235 static int 236 compressed_sl_print(netdissect_options *ndo, 237 const u_char *chdr, const struct ip *ip, 238 u_int length, int dir) 239 { 240 register const u_char *cp = chdr; 241 register u_int flags, hlen; 242 243 flags = *cp++; 244 if (flags & NEW_C) { 245 lastconn = *cp++; 246 ND_PRINT((ndo, "ctcp %d", lastconn)); 247 } else 248 ND_PRINT((ndo, "ctcp *")); 249 250 /* skip tcp checksum */ 251 cp += 2; 252 253 switch (flags & SPECIALS_MASK) { 254 case SPECIAL_I: 255 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn])); 256 break; 257 258 case SPECIAL_D: 259 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn])); 260 break; 261 262 default: 263 if (flags & NEW_U) 264 cp = print_sl_change(ndo, "U=", cp); 265 if (flags & NEW_W) 266 cp = print_sl_winchange(ndo, cp); 267 if (flags & NEW_A) 268 cp = print_sl_change(ndo, "A+", cp); 269 if (flags & NEW_S) 270 cp = print_sl_change(ndo, "S+", cp); 271 break; 272 } 273 if (flags & NEW_I) 274 cp = print_sl_change(ndo, "I+", cp); 275 276 /* 277 * 'hlen' is the length of the uncompressed TCP/IP header (in words). 278 * 'cp - chdr' is the length of the compressed header. 279 * 'length - hlen' is the amount of data in the packet. 280 */ 281 ND_TCHECK(*ip); 282 hlen = IP_HL(ip); 283 ND_TCHECK(*((const struct tcphdr *)&((const int32_t *)ip)[hlen])); 284 hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 285 lastlen[dir][lastconn] = length - (hlen << 2); 286 ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr))); 287 return 0; 288 trunc: 289 return -1; 290 } 291