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 #include <config.h> 25 26 #include "netdissect-stdinc.h" 27 28 #define ND_LONGJMP_FROM_TCHECK 29 #include "netdissect.h" 30 #include "extract.h" 31 32 #include "ip.h" 33 #include "tcp.h" 34 #include "slcompress.h" 35 36 /* 37 * definitions of the pseudo- link-level header attached to slip 38 * packets grabbed by the packet filter (bpf) traffic monitor. 39 */ 40 #define SLIP_HDRLEN 16 41 42 #define SLX_DIR 0 43 #define SLX_CHDR 1 44 45 #define SLIPDIR_IN 0 46 #define SLIPDIR_OUT 1 47 48 49 static u_int lastlen[2][256]; 50 static u_int lastconn = 255; 51 52 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int); 53 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int); 54 55 void 56 sl_if_print(netdissect_options *ndo, 57 const struct pcap_pkthdr *h, const u_char *p) 58 { 59 u_int length = h->len; 60 const struct ip *ip; 61 62 ndo->ndo_protocol = "slip"; 63 ND_TCHECK_LEN(p, SLIP_HDRLEN); 64 ndo->ndo_ll_hdr_len += SLIP_HDRLEN; 65 66 length -= SLIP_HDRLEN; 67 68 ip = (const struct ip *)(p + SLIP_HDRLEN); 69 70 if (ndo->ndo_eflag) 71 sliplink_print(ndo, p, ip, length); 72 73 switch (IP_V(ip)) { 74 case 4: 75 ip_print(ndo, (const u_char *)ip, length); 76 break; 77 case 6: 78 ip6_print(ndo, (const u_char *)ip, length); 79 break; 80 default: 81 ND_PRINT("ip v%u", IP_V(ip)); 82 } 83 } 84 85 void 86 sl_bsdos_if_print(netdissect_options *ndo, 87 const struct pcap_pkthdr *h, const u_char *p) 88 { 89 u_int length = h->len; 90 const struct ip *ip; 91 92 ndo->ndo_protocol = "slip_bsdos"; 93 ND_TCHECK_LEN(p, SLIP_HDRLEN); 94 ndo->ndo_ll_hdr_len += SLIP_HDRLEN; 95 96 length -= SLIP_HDRLEN; 97 98 ip = (const struct ip *)(p + SLIP_HDRLEN); 99 100 #ifdef notdef 101 if (ndo->ndo_eflag) 102 sliplink_print(ndo, p, ip, length); 103 #endif 104 105 ip_print(ndo, (const u_char *)ip, length); 106 } 107 108 static void 109 sliplink_print(netdissect_options *ndo, 110 const u_char *p, const struct ip *ip, 111 u_int length) 112 { 113 int dir; 114 u_int hlen; 115 116 dir = GET_U_1(p + SLX_DIR); 117 switch (dir) { 118 119 case SLIPDIR_IN: 120 ND_PRINT("I "); 121 break; 122 123 case SLIPDIR_OUT: 124 ND_PRINT("O "); 125 break; 126 127 default: 128 ND_PRINT("Invalid direction %d ", dir); 129 dir = -1; 130 break; 131 } 132 switch (GET_U_1(p + SLX_CHDR) & 0xf0) { 133 134 case TYPE_IP: 135 ND_PRINT("ip %u: ", length + SLIP_HDRLEN); 136 break; 137 138 case TYPE_UNCOMPRESSED_TCP: 139 /* 140 * The connection id is stored in the IP protocol field. 141 * Get it from the link layer since sl_uncompress_tcp() 142 * has restored the IP header copy to IPPROTO_TCP. 143 */ 144 lastconn = GET_U_1(((const struct ip *)(p + SLX_CHDR))->ip_p); 145 ND_PRINT("utcp %u: ", lastconn); 146 if (dir == -1) { 147 /* Direction is bogus, don't use it */ 148 return; 149 } 150 ND_TCHECK_SIZE(ip); 151 hlen = IP_HL(ip); 152 ND_TCHECK_SIZE((const struct tcphdr *)&((const int *)ip)[hlen]); 153 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]); 154 lastlen[dir][lastconn] = length - (hlen << 2); 155 break; 156 157 default: 158 if (dir == -1) { 159 /* Direction is bogus, don't use it */ 160 return; 161 } 162 if (GET_U_1(p + SLX_CHDR) & TYPE_COMPRESSED_TCP) { 163 compressed_sl_print(ndo, p + SLX_CHDR, ip, length, dir); 164 ND_PRINT(": "); 165 } else 166 ND_PRINT("slip-%u!: ", GET_U_1(p + SLX_CHDR)); 167 } 168 } 169 170 static const u_char * 171 print_sl_change(netdissect_options *ndo, 172 const char *str, const u_char *cp) 173 { 174 u_int i; 175 176 if ((i = GET_U_1(cp)) == 0) { 177 cp++; 178 i = GET_BE_U_2(cp); 179 cp += 2; 180 } 181 ND_PRINT(" %s%u", str, i); 182 return (cp); 183 } 184 185 static const u_char * 186 print_sl_winchange(netdissect_options *ndo, 187 const u_char *cp) 188 { 189 int16_t i; 190 191 if ((i = GET_U_1(cp)) == 0) { 192 cp++; 193 i = GET_BE_S_2(cp); 194 cp += 2; 195 } 196 if (i >= 0) 197 ND_PRINT(" W+%d", i); 198 else 199 ND_PRINT(" W%d", i); 200 return (cp); 201 } 202 203 static void 204 compressed_sl_print(netdissect_options *ndo, 205 const u_char *chdr, const struct ip *ip, 206 u_int length, int dir) 207 { 208 const u_char *cp = chdr; 209 u_int flags, hlen; 210 211 flags = GET_U_1(cp); 212 cp++; 213 if (flags & NEW_C) { 214 lastconn = GET_U_1(cp); 215 cp++; 216 ND_PRINT("ctcp %u", lastconn); 217 } else 218 ND_PRINT("ctcp *"); 219 220 /* skip tcp checksum */ 221 cp += 2; 222 223 switch (flags & SPECIALS_MASK) { 224 case SPECIAL_I: 225 ND_PRINT(" *SA+%u", lastlen[dir][lastconn]); 226 break; 227 228 case SPECIAL_D: 229 ND_PRINT(" *S+%u", lastlen[dir][lastconn]); 230 break; 231 232 default: 233 if (flags & NEW_U) 234 cp = print_sl_change(ndo, "U=", cp); 235 if (flags & NEW_W) 236 cp = print_sl_winchange(ndo, cp); 237 if (flags & NEW_A) 238 cp = print_sl_change(ndo, "A+", cp); 239 if (flags & NEW_S) 240 cp = print_sl_change(ndo, "S+", cp); 241 break; 242 } 243 if (flags & NEW_I) 244 cp = print_sl_change(ndo, "I+", cp); 245 246 /* 247 * 'hlen' is the length of the uncompressed TCP/IP header (in words). 248 * 'cp - chdr' is the length of the compressed header. 249 * 'length - hlen' is the amount of data in the packet. 250 */ 251 ND_TCHECK_SIZE(ip); 252 hlen = IP_HL(ip); 253 ND_TCHECK_SIZE((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 254 hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]); 255 lastlen[dir][lastconn] = length - (hlen << 2); 256 ND_PRINT(" %u (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)); 257 } 258