1 /* 2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 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 #define NETDISSECT_REWORKED 23 #ifdef HAVE_CONFIG_H 24 #include "config.h" 25 #endif 26 27 #include <tcpdump-stdinc.h> 28 29 #include "interface.h" 30 #include "addrtoname.h" 31 #include "ethertype.h" 32 #include "extract.h" 33 34 #include "ether.h" 35 36 /* 37 * For captures on Linux cooked sockets, we construct a fake header 38 * that includes: 39 * 40 * a 2-byte "packet type" which is one of: 41 * 42 * LINUX_SLL_HOST packet was sent to us 43 * LINUX_SLL_BROADCAST packet was broadcast 44 * LINUX_SLL_MULTICAST packet was multicast 45 * LINUX_SLL_OTHERHOST packet was sent to somebody else 46 * LINUX_SLL_OUTGOING packet was sent *by* us; 47 * 48 * a 2-byte Ethernet protocol field; 49 * 50 * a 2-byte link-layer type; 51 * 52 * a 2-byte link-layer address length; 53 * 54 * an 8-byte source link-layer address, whose actual length is 55 * specified by the previous value. 56 * 57 * All fields except for the link-layer address are in network byte order. 58 * 59 * DO NOT change the layout of this structure, or change any of the 60 * LINUX_SLL_ values below. If you must change the link-layer header 61 * for a "cooked" Linux capture, introduce a new DLT_ type (ask 62 * "tcpdump-workers (at) lists.tcpdump.org" for one, so that you don't give it 63 * a value that collides with a value already being used), and use the 64 * new header in captures of that type, so that programs that can 65 * handle DLT_LINUX_SLL captures will continue to handle them correctly 66 * without any change, and so that capture files with different headers 67 * can be told apart and programs that read them can dissect the 68 * packets in them. 69 * 70 * This structure, and the #defines below, must be the same in the 71 * libpcap and tcpdump versions of "sll.h". 72 */ 73 74 /* 75 * A DLT_LINUX_SLL fake link-layer header. 76 */ 77 #define SLL_HDR_LEN 16 /* total header length */ 78 #define SLL_ADDRLEN 8 /* length of address field */ 79 80 struct sll_header { 81 uint16_t sll_pkttype; /* packet type */ 82 uint16_t sll_hatype; /* link-layer address type */ 83 uint16_t sll_halen; /* link-layer address length */ 84 uint8_t sll_addr[SLL_ADDRLEN]; /* link-layer address */ 85 uint16_t sll_protocol; /* protocol */ 86 }; 87 88 /* 89 * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the 90 * PACKET_ values on Linux, but are defined here so that they're 91 * available even on systems other than Linux, and so that they 92 * don't change even if the PACKET_ values change. 93 */ 94 #define LINUX_SLL_HOST 0 95 #define LINUX_SLL_BROADCAST 1 96 #define LINUX_SLL_MULTICAST 2 97 #define LINUX_SLL_OTHERHOST 3 98 #define LINUX_SLL_OUTGOING 4 99 100 /* 101 * The LINUX_SLL_ values for "sll_protocol"; these correspond to the 102 * ETH_P_ values on Linux, but are defined here so that they're 103 * available even on systems other than Linux. We assume, for now, 104 * that the ETH_P_ values won't change in Linux; if they do, then: 105 * 106 * if we don't translate them in "pcap-linux.c", capture files 107 * won't necessarily be readable if captured on a system that 108 * defines ETH_P_ values that don't match these values; 109 * 110 * if we do translate them in "pcap-linux.c", that makes life 111 * unpleasant for the BPF code generator, as the values you test 112 * for in the kernel aren't the values that you test for when 113 * reading a capture file, so the fixup code run on BPF programs 114 * handed to the kernel ends up having to do more work. 115 * 116 * Add other values here as necessary, for handling packet types that 117 * might show up on non-Ethernet, non-802.x networks. (Not all the ones 118 * in the Linux "if_ether.h" will, I suspect, actually show up in 119 * captures.) 120 */ 121 #define LINUX_SLL_P_802_3 0x0001 /* Novell 802.3 frames without 802.2 LLC header */ 122 #define LINUX_SLL_P_802_2 0x0004 /* 802.2 frames (not D/I/X Ethernet) */ 123 124 static const struct tok sll_pkttype_values[] = { 125 { LINUX_SLL_HOST, "In" }, 126 { LINUX_SLL_BROADCAST, "B" }, 127 { LINUX_SLL_MULTICAST, "M" }, 128 { LINUX_SLL_OTHERHOST, "P" }, 129 { LINUX_SLL_OUTGOING, "Out" }, 130 { 0, NULL} 131 }; 132 133 static inline void 134 sll_print(netdissect_options *ndo, register const struct sll_header *sllp, u_int length) 135 { 136 u_short ether_type; 137 138 ND_PRINT((ndo, "%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_16BITS(&sllp->sll_pkttype)))); 139 140 /* 141 * XXX - check the link-layer address type value? 142 * For now, we just assume 6 means Ethernet. 143 * XXX - print others as strings of hex? 144 */ 145 if (EXTRACT_16BITS(&sllp->sll_halen) == 6) 146 ND_PRINT((ndo, "%s ", etheraddr_string(ndo, sllp->sll_addr))); 147 148 if (!ndo->ndo_qflag) { 149 ether_type = EXTRACT_16BITS(&sllp->sll_protocol); 150 151 if (ether_type <= ETHERMTU) { 152 /* 153 * Not an Ethernet type; what type is it? 154 */ 155 switch (ether_type) { 156 157 case LINUX_SLL_P_802_3: 158 /* 159 * Ethernet_802.3 IPX frame. 160 */ 161 ND_PRINT((ndo, "802.3")); 162 break; 163 164 case LINUX_SLL_P_802_2: 165 /* 166 * 802.2. 167 */ 168 ND_PRINT((ndo, "802.2")); 169 break; 170 171 default: 172 /* 173 * What is it? 174 */ 175 ND_PRINT((ndo, "ethertype Unknown (0x%04x)", 176 ether_type)); 177 break; 178 } 179 } else { 180 ND_PRINT((ndo, "ethertype %s (0x%04x)", 181 tok2str(ethertype_values, "Unknown", ether_type), 182 ether_type)); 183 } 184 ND_PRINT((ndo, ", length %u: ", length)); 185 } 186 } 187 188 /* 189 * This is the top level routine of the printer. 'p' points to the 190 * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp, 191 * 'h->len' is the length of the packet off the wire, and 'h->caplen' 192 * is the number of bytes actually captured. 193 */ 194 u_int 195 sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 196 { 197 u_int caplen = h->caplen; 198 u_int length = h->len; 199 register const struct sll_header *sllp; 200 u_short ether_type; 201 u_short extracted_ethertype; 202 203 if (caplen < SLL_HDR_LEN) { 204 /* 205 * XXX - this "can't happen" because "pcap-linux.c" always 206 * adds this many bytes of header to every packet in a 207 * cooked socket capture. 208 */ 209 ND_PRINT((ndo, "[|sll]")); 210 return (caplen); 211 } 212 213 sllp = (const struct sll_header *)p; 214 215 if (ndo->ndo_eflag) 216 sll_print(ndo, sllp, length); 217 218 /* 219 * Go past the cooked-mode header. 220 */ 221 length -= SLL_HDR_LEN; 222 caplen -= SLL_HDR_LEN; 223 p += SLL_HDR_LEN; 224 225 ether_type = EXTRACT_16BITS(&sllp->sll_protocol); 226 227 recurse: 228 /* 229 * Is it (gag) an 802.3 encapsulation, or some non-Ethernet 230 * packet type? 231 */ 232 if (ether_type <= ETHERMTU) { 233 /* 234 * Yes - what type is it? 235 */ 236 switch (ether_type) { 237 238 case LINUX_SLL_P_802_3: 239 /* 240 * Ethernet_802.3 IPX frame. 241 */ 242 ipx_print(ndo, p, length); 243 break; 244 245 case LINUX_SLL_P_802_2: 246 /* 247 * 802.2. 248 * Try to print the LLC-layer header & higher layers. 249 */ 250 if (llc_print(ndo, p, length, caplen, NULL, NULL, 251 &extracted_ethertype) == 0) 252 goto unknown; /* unknown LLC type */ 253 break; 254 255 default: 256 extracted_ethertype = 0; 257 /*FALLTHROUGH*/ 258 259 unknown: 260 /* ether_type not known, print raw packet */ 261 if (!ndo->ndo_eflag) 262 sll_print(ndo, sllp, length + SLL_HDR_LEN); 263 if (extracted_ethertype) { 264 ND_PRINT((ndo, "(LLC %s) ", 265 etherproto_string(htons(extracted_ethertype)))); 266 } 267 if (!ndo->ndo_suppress_default_print) 268 ND_DEFAULTPRINT(p, caplen); 269 break; 270 } 271 } else if (ether_type == ETHERTYPE_8021Q) { 272 /* 273 * Print VLAN information, and then go back and process 274 * the enclosed type field. 275 */ 276 if (caplen < 4 || length < 4) { 277 ND_PRINT((ndo, "[|vlan]")); 278 return (SLL_HDR_LEN); 279 } 280 if (ndo->ndo_eflag) { 281 uint16_t tag = EXTRACT_16BITS(p); 282 283 ND_PRINT((ndo, "%s, ", ieee8021q_tci_string(tag))); 284 } 285 286 ether_type = EXTRACT_16BITS(p + 2); 287 if (ether_type <= ETHERMTU) 288 ether_type = LINUX_SLL_P_802_2; 289 if (!ndo->ndo_qflag) { 290 ND_PRINT((ndo, "ethertype %s, ", 291 tok2str(ethertype_values, "Unknown", ether_type))); 292 } 293 p += 4; 294 length -= 4; 295 caplen -= 4; 296 goto recurse; 297 } else { 298 if (ethertype_print(ndo, ether_type, p, length, caplen) == 0) { 299 /* ether_type not known, print raw packet */ 300 if (!ndo->ndo_eflag) 301 sll_print(ndo, sllp, length + SLL_HDR_LEN); 302 if (!ndo->ndo_suppress_default_print) 303 ND_DEFAULTPRINT(p, caplen); 304 } 305 } 306 307 return (SLL_HDR_LEN); 308 } 309
