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 #include <sys/cdefs.h> 23 #ifndef lint 24 __RCSID("$NetBSD: print-sl.c,v 1.9 2019/10/01 16:06:16 christos Exp $"); 25 #endif 26 27 /* \summary: Compressed Serial Line Internet Protocol printer */ 28 29 #ifdef HAVE_CONFIG_H 30 #include "config.h" 31 #endif 32 33 #include <netdissect-stdinc.h> 34 35 #include "netdissect.h" 36 #include "extract.h" 37 38 #include "ip.h" 39 #include "tcp.h" 40 #include "slcompress.h" 41 42 /* 43 * definitions of the pseudo- link-level header attached to slip 44 * packets grabbed by the packet filter (bpf) traffic monitor. 45 */ 46 #define SLIP_HDRLEN 16 47 48 #define SLX_DIR 0 49 #define SLX_CHDR 1 50 #define CHDR_LEN 15 51 52 #define SLIPDIR_IN 0 53 #define SLIPDIR_OUT 1 54 55 static const char tstr[] = "[|slip]"; 56 57 static u_int lastlen[2][256]; 58 static u_int lastconn = 255; 59 60 static int sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int); 61 static int compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int); 62 63 u_int 64 sl_if_print(netdissect_options *ndo, 65 const struct pcap_pkthdr *h, const u_char *p) 66 { 67 register u_int caplen = h->caplen; 68 register u_int length = h->len; 69 register const struct ip *ip; 70 71 if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) { 72 ND_PRINT((ndo, "%s", tstr)); 73 return (caplen); 74 } 75 76 caplen -= SLIP_HDRLEN; 77 length -= SLIP_HDRLEN; 78 79 ip = (const struct ip *)(p + SLIP_HDRLEN); 80 81 if (ndo->ndo_eflag) 82 if (sliplink_print(ndo, p, ip, length) == -1) { 83 ND_PRINT((ndo, "%s", tstr)); 84 return (caplen + SLIP_HDRLEN); 85 } 86 87 if (caplen < 1 || length < 1) { 88 ND_PRINT((ndo, "%s", tstr)); 89 return (caplen + SLIP_HDRLEN); 90 } 91 92 switch (IP_V(ip)) { 93 case 4: 94 ip_print(ndo, (const u_char *)ip, length); 95 break; 96 case 6: 97 ip6_print(ndo, (const u_char *)ip, length); 98 break; 99 default: 100 ND_PRINT((ndo, "ip v%d", IP_V(ip))); 101 } 102 103 return (SLIP_HDRLEN); 104 } 105 106 u_int 107 sl_bsdos_if_print(netdissect_options *ndo, 108 const struct pcap_pkthdr *h, const u_char *p) 109 { 110 register u_int caplen = h->caplen; 111 register u_int length = h->len; 112 register const struct ip *ip; 113 114 if (caplen < SLIP_HDRLEN) { 115 ND_PRINT((ndo, "%s", tstr)); 116 return (caplen); 117 } 118 119 length -= SLIP_HDRLEN; 120 121 ip = (const struct ip *)(p + SLIP_HDRLEN); 122 123 #ifdef notdef 124 if (ndo->ndo_eflag) 125 sliplink_print(ndo, p, ip, length); 126 #endif 127 128 ip_print(ndo, (const u_char *)ip, length); 129 130 return (SLIP_HDRLEN); 131 } 132 133 static int 134 sliplink_print(netdissect_options *ndo, 135 register const u_char *p, register const struct ip *ip, 136 register u_int length) 137 { 138 int dir; 139 u_int hlen; 140 141 dir = p[SLX_DIR]; 142 switch (dir) { 143 144 case SLIPDIR_IN: 145 ND_PRINT((ndo, "I ")); 146 break; 147 148 case SLIPDIR_OUT: 149 ND_PRINT((ndo, "O ")); 150 break; 151 152 default: 153 ND_PRINT((ndo, "Invalid direction %d ", dir)); 154 dir = -1; 155 break; 156 } 157 if (ndo->ndo_nflag) { 158 /* XXX just dump the header */ 159 register int i; 160 161 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i) 162 ND_PRINT((ndo, "%02x.", p[i])); 163 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1])); 164 return 0; 165 } 166 switch (p[SLX_CHDR] & 0xf0) { 167 168 case TYPE_IP: 169 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN)); 170 break; 171 172 case TYPE_UNCOMPRESSED_TCP: 173 /* 174 * The connection id is stored in the IP protocol field. 175 * Get it from the link layer since sl_uncompress_tcp() 176 * has restored the IP header copy to IPPROTO_TCP. 177 */ 178 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p; 179 ND_PRINT((ndo, "utcp %d: ", lastconn)); 180 if (dir == -1) { 181 /* Direction is bogus, don't use it */ 182 return 0; 183 } 184 ND_TCHECK(*ip); 185 hlen = IP_HL(ip); 186 ND_TCHECK(*((const struct tcphdr *)&((const int *)ip)[hlen])); 187 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]); 188 lastlen[dir][lastconn] = length - (hlen << 2); 189 break; 190 191 default: 192 if (dir == -1) { 193 /* Direction is bogus, don't use it */ 194 return 0; 195 } 196 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) { 197 if (compressed_sl_print(ndo, &p[SLX_CHDR], ip, 198 length, dir) == -1) 199 goto trunc; 200 ND_PRINT((ndo, ": ")); 201 } else 202 ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR])); 203 } 204 return 0; 205 trunc: 206 return -1; 207 } 208 209 static const u_char * 210 print_sl_change(netdissect_options *ndo, 211 const char *str, register const u_char *cp) 212 { 213 register u_int i; 214 215 if ((i = *cp++) == 0) { 216 i = EXTRACT_16BITS(cp); 217 cp += 2; 218 } 219 ND_PRINT((ndo, " %s%d", str, i)); 220 return (cp); 221 } 222 223 static const u_char * 224 print_sl_winchange(netdissect_options *ndo, 225 register const u_char *cp) 226 { 227 register short i; 228 229 if ((i = *cp++) == 0) { 230 i = EXTRACT_16BITS(cp); 231 cp += 2; 232 } 233 if (i >= 0) 234 ND_PRINT((ndo, " W+%d", i)); 235 else 236 ND_PRINT((ndo, " W%d", i)); 237 return (cp); 238 } 239 240 static int 241 compressed_sl_print(netdissect_options *ndo, 242 const u_char *chdr, const struct ip *ip, 243 u_int length, int dir) 244 { 245 register const u_char *cp = chdr; 246 register u_int flags, hlen; 247 248 flags = *cp++; 249 if (flags & NEW_C) { 250 lastconn = *cp++; 251 ND_PRINT((ndo, "ctcp %d", lastconn)); 252 } else 253 ND_PRINT((ndo, "ctcp *")); 254 255 /* skip tcp checksum */ 256 cp += 2; 257 258 switch (flags & SPECIALS_MASK) { 259 case SPECIAL_I: 260 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn])); 261 break; 262 263 case SPECIAL_D: 264 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn])); 265 break; 266 267 default: 268 if (flags & NEW_U) 269 cp = print_sl_change(ndo, "U=", cp); 270 if (flags & NEW_W) 271 cp = print_sl_winchange(ndo, cp); 272 if (flags & NEW_A) 273 cp = print_sl_change(ndo, "A+", cp); 274 if (flags & NEW_S) 275 cp = print_sl_change(ndo, "S+", cp); 276 break; 277 } 278 if (flags & NEW_I) 279 cp = print_sl_change(ndo, "I+", cp); 280 281 /* 282 * 'hlen' is the length of the uncompressed TCP/IP header (in words). 283 * 'cp - chdr' is the length of the compressed header. 284 * 'length - hlen' is the amount of data in the packet. 285 */ 286 ND_TCHECK(*ip); 287 hlen = IP_HL(ip); 288 ND_TCHECK(*((const struct tcphdr *)&((const int32_t *)ip)[hlen])); 289 hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 290 lastlen[dir][lastconn] = length - (hlen << 2); 291 ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr))); 292 return 0; 293 trunc: 294 return -1; 295 } 296