1 /* 2 * Copyright (c) 1988-1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Copyright (c) 1998-2012 Michael Richardson <mcr@tcpdump.org> 6 * The TCPDUMP project 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that: (1) source code distributions 10 * retain the above copyright notice and this paragraph in its entirety, (2) 11 * distributions including binary code include the above copyright notice and 12 * this paragraph in its entirety in the documentation or other materials 13 * provided with the distribution, and (3) all advertising materials mentioning 14 * features or use of this software display the following acknowledgement: 15 * ``This product includes software developed by the University of California, 16 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 17 * the University nor the names of its contributors may be used to endorse 18 * or promote products derived from this software without specific prior 19 * written permission. 20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 21 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 23 */ 24 25 #ifdef HAVE_CONFIG_H 26 #include <config.h> 27 #endif 28 29 #include "netdissect-stdinc.h" 30 #include "netdissect.h" 31 #include <string.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 35 #ifdef USE_LIBSMI 36 #include <smi.h> 37 #endif 38 39 /* 40 * Initialize anything that must be initialized before dissecting 41 * packets. 42 * 43 * This should be called at the beginning of the program; it does 44 * not need to be called, and should not be called, for every 45 * netdissect_options structure. 46 */ 47 int 48 nd_init(char *errbuf, size_t errbuf_size) 49 { 50 #ifdef _WIN32 51 WORD wVersionRequested; 52 WSADATA wsaData; 53 int err; 54 55 /* 56 * Request Winsock 2.2; we expect Winsock 2. 57 */ 58 wVersionRequested = MAKEWORD(2, 2); 59 err = WSAStartup(wVersionRequested, &wsaData); 60 if (err != 0) { 61 strlcpy(errbuf, "Attempting to initialize Winsock failed", 62 errbuf_size); 63 return (-1); 64 } 65 #endif /* _WIN32 */ 66 67 #ifdef USE_LIBSMI 68 /* 69 * XXX - should we just fail if this fails? Some of the 70 * libsmi calls may fail. 71 */ 72 smiInit("tcpdump"); 73 #endif 74 75 /* 76 * Clears the error buffer, and uses it so we don't get 77 * "unused argument" warnings at compile time. 78 */ 79 strlcpy(errbuf, "", errbuf_size); 80 return (0); 81 } 82 83 /* 84 * Clean up anything that ndo_init() did. 85 */ 86 void 87 nd_cleanup(void) 88 { 89 #ifdef USE_LIBSMI 90 /* 91 * This appears, in libsmi 0.4.8, to do nothing if smiInit() 92 * wasn't done or failed, so we call it unconditionally. 93 */ 94 smiExit(); 95 #endif 96 97 #ifdef _WIN32 98 /* 99 * Undo the WSAStartup() call above. 100 */ 101 WSACleanup(); 102 #endif 103 } 104 105 int 106 nd_have_smi_support(void) 107 { 108 #ifdef USE_LIBSMI 109 return (1); 110 #else 111 return (0); 112 #endif 113 } 114 115 /* 116 * Indicates whether an SMI module has been loaded, so that we can use 117 * libsmi to translate OIDs. 118 */ 119 int nd_smi_module_loaded; 120 121 int 122 nd_load_smi_module(const char *module, char *errbuf, size_t errbuf_size) 123 { 124 #ifdef USE_LIBSMI 125 if (smiLoadModule(module) == 0) { 126 snprintf(errbuf, errbuf_size, "could not load MIB module %s", 127 module); 128 return (-1); 129 } 130 nd_smi_module_loaded = 1; 131 return (0); 132 #else 133 snprintf(errbuf, errbuf_size, "MIB module %s not loaded: no libsmi support", 134 module); 135 return (-1); 136 #endif 137 } 138 139 const char * 140 nd_smi_version_string(void) 141 { 142 #ifdef USE_LIBSMI 143 return (smi_version_string); 144 #else 145 return (NULL); 146 #endif 147 } 148 149 150 int 151 nd_push_buffer(netdissect_options *ndo, u_char *new_buffer, 152 const u_char *new_packetp, const u_char *new_snapend) 153 { 154 struct netdissect_saved_packet_info *ndspi; 155 156 ndspi = (struct netdissect_saved_packet_info *)malloc(sizeof(struct netdissect_saved_packet_info)); 157 if (ndspi == NULL) 158 return (0); /* fail */ 159 ndspi->ndspi_buffer = new_buffer; 160 ndspi->ndspi_packetp = ndo->ndo_packetp; 161 ndspi->ndspi_snapend = ndo->ndo_snapend; 162 ndspi->ndspi_prev = ndo->ndo_packet_info_stack; 163 164 ndo->ndo_packetp = new_packetp; 165 ndo->ndo_snapend = new_snapend; 166 ndo->ndo_packet_info_stack = ndspi; 167 168 return (1); /* success */ 169 } 170 171 /* 172 * Set a new snapshot end to the minimum of the existing snapshot end 173 * and the new snapshot end. 174 */ 175 int 176 nd_push_snapend(netdissect_options *ndo, const u_char *new_snapend) 177 { 178 struct netdissect_saved_packet_info *ndspi; 179 180 ndspi = (struct netdissect_saved_packet_info *)malloc(sizeof(struct netdissect_saved_packet_info)); 181 if (ndspi == NULL) 182 return (0); /* fail */ 183 ndspi->ndspi_buffer = NULL; /* no new buffer */ 184 ndspi->ndspi_packetp = ndo->ndo_packetp; 185 ndspi->ndspi_snapend = ndo->ndo_snapend; 186 ndspi->ndspi_prev = ndo->ndo_packet_info_stack; 187 188 /* No new packet pointer, either */ 189 if (new_snapend < ndo->ndo_snapend) 190 ndo->ndo_snapend = new_snapend; 191 ndo->ndo_packet_info_stack = ndspi; 192 193 return (1); /* success */ 194 } 195 196 /* 197 * Change an already-pushed snapshot end. This may increase the 198 * snapshot end, as it may be used, for example, for a Jumbo Payload 199 * option in IPv6. It must not increase it past the snapshot length 200 * atop which the current one was pushed, however. 201 */ 202 void 203 nd_change_snapend(netdissect_options *ndo, const u_char *new_snapend) 204 { 205 struct netdissect_saved_packet_info *ndspi; 206 207 ndspi = ndo->ndo_packet_info_stack; 208 if (ndspi->ndspi_prev != NULL) { 209 if (new_snapend <= ndspi->ndspi_prev->ndspi_snapend) 210 ndo->ndo_snapend = new_snapend; 211 } else { 212 if (new_snapend < ndo->ndo_snapend) 213 ndo->ndo_snapend = new_snapend; 214 } 215 } 216 217 void 218 nd_pop_packet_info(netdissect_options *ndo) 219 { 220 struct netdissect_saved_packet_info *ndspi; 221 222 ndspi = ndo->ndo_packet_info_stack; 223 ndo->ndo_packetp = ndspi->ndspi_packetp; 224 ndo->ndo_snapend = ndspi->ndspi_snapend; 225 ndo->ndo_packet_info_stack = ndspi->ndspi_prev; 226 227 free(ndspi->ndspi_buffer); 228 free(ndspi); 229 } 230 231 void 232 nd_pop_all_packet_info(netdissect_options *ndo) 233 { 234 while (ndo->ndo_packet_info_stack != NULL) 235 nd_pop_packet_info(ndo); 236 } 237