1 /* 2 * WPA Supplicant - Layer2 packet handling with libpcap/libdnet and WinPcap 3 * Copyright (c) 2003-2006, Jouni Malinen <j@w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15 #include "includes.h" 16 #ifndef CONFIG_NATIVE_WINDOWS 17 #include <sys/ioctl.h> 18 #endif /* CONFIG_NATIVE_WINDOWS */ 19 #include <pcap.h> 20 #ifndef CONFIG_WINPCAP 21 #include <dnet.h> 22 #endif /* CONFIG_WINPCAP */ 23 24 #include "common.h" 25 #include "eloop.h" 26 #include "l2_packet.h" 27 28 29 static const u8 pae_group_addr[ETH_ALEN] = 30 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 }; 31 32 struct l2_packet_data { 33 pcap_t *pcap; 34 #ifdef CONFIG_WINPCAP 35 unsigned int num_fast_poll; 36 #else /* CONFIG_WINPCAP */ 37 eth_t *eth; 38 #endif /* CONFIG_WINPCAP */ 39 char ifname[100]; 40 u8 own_addr[ETH_ALEN]; 41 void (*rx_callback)(void *ctx, const u8 *src_addr, 42 const u8 *buf, size_t len); 43 void *rx_callback_ctx; 44 int l2_hdr; /* whether to include layer 2 (Ethernet) header in calls 45 * to rx_callback */ 46 }; 47 48 49 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr) 50 { 51 os_memcpy(addr, l2->own_addr, ETH_ALEN); 52 return 0; 53 } 54 55 56 #ifndef CONFIG_WINPCAP 57 static int l2_packet_init_libdnet(struct l2_packet_data *l2) 58 { 59 eth_addr_t own_addr; 60 61 l2->eth = eth_open(l2->ifname); 62 if (!l2->eth) { 63 printf("Failed to open interface '%s'.\n", l2->ifname); 64 perror("eth_open"); 65 return -1; 66 } 67 68 if (eth_get(l2->eth, &own_addr) < 0) { 69 printf("Failed to get own hw address from interface '%s'.\n", 70 l2->ifname); 71 perror("eth_get"); 72 eth_close(l2->eth); 73 l2->eth = NULL; 74 return -1; 75 } 76 os_memcpy(l2->own_addr, own_addr.data, ETH_ALEN); 77 78 return 0; 79 } 80 #endif /* CONFIG_WINPCAP */ 81 82 83 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 84 const u8 *buf, size_t len) 85 { 86 int ret; 87 struct l2_ethhdr *eth; 88 89 if (l2 == NULL) 90 return -1; 91 92 if (l2->l2_hdr) { 93 #ifdef CONFIG_WINPCAP 94 ret = pcap_sendpacket(l2->pcap, buf, len); 95 #else /* CONFIG_WINPCAP */ 96 ret = eth_send(l2->eth, buf, len); 97 #endif /* CONFIG_WINPCAP */ 98 } else { 99 size_t mlen = sizeof(*eth) + len; 100 eth = os_malloc(mlen); 101 if (eth == NULL) 102 return -1; 103 104 os_memcpy(eth->h_dest, dst_addr, ETH_ALEN); 105 os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN); 106 eth->h_proto = htons(proto); 107 os_memcpy(eth + 1, buf, len); 108 109 #ifdef CONFIG_WINPCAP 110 ret = pcap_sendpacket(l2->pcap, (u8 *) eth, mlen); 111 #else /* CONFIG_WINPCAP */ 112 ret = eth_send(l2->eth, (u8 *) eth, mlen); 113 #endif /* CONFIG_WINPCAP */ 114 115 os_free(eth); 116 } 117 118 return ret; 119 } 120 121 122 #ifndef CONFIG_WINPCAP 123 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) 124 { 125 struct l2_packet_data *l2 = eloop_ctx; 126 pcap_t *pcap = sock_ctx; 127 struct pcap_pkthdr hdr; 128 const u_char *packet; 129 struct l2_ethhdr *ethhdr; 130 unsigned char *buf; 131 size_t len; 132 133 packet = pcap_next(pcap, &hdr); 134 135 if (packet == NULL || hdr.caplen < sizeof(*ethhdr)) 136 return; 137 138 ethhdr = (struct l2_ethhdr *) packet; 139 if (l2->l2_hdr) { 140 buf = (unsigned char *) ethhdr; 141 len = hdr.caplen; 142 } else { 143 buf = (unsigned char *) (ethhdr + 1); 144 len = hdr.caplen - sizeof(*ethhdr); 145 } 146 l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len); 147 } 148 #endif /* CONFIG_WINPCAP */ 149 150 151 #ifdef CONFIG_WINPCAP 152 static void l2_packet_receive_cb(u_char *user, const struct pcap_pkthdr *hdr, 153 const u_char *pkt_data) 154 { 155 struct l2_packet_data *l2 = (struct l2_packet_data *) user; 156 struct l2_ethhdr *ethhdr; 157 unsigned char *buf; 158 size_t len; 159 160 if (pkt_data == NULL || hdr->caplen < sizeof(*ethhdr)) 161 return; 162 163 ethhdr = (struct l2_ethhdr *) pkt_data; 164 if (l2->l2_hdr) { 165 buf = (unsigned char *) ethhdr; 166 len = hdr->caplen; 167 } else { 168 buf = (unsigned char *) (ethhdr + 1); 169 len = hdr->caplen - sizeof(*ethhdr); 170 } 171 l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len); 172 /* 173 * Use shorter poll interval for 3 seconds to reduce latency during key 174 * handshake. 175 */ 176 l2->num_fast_poll = 3 * 50; 177 } 178 179 180 static void l2_packet_receive_timeout(void *eloop_ctx, void *timeout_ctx) 181 { 182 struct l2_packet_data *l2 = eloop_ctx; 183 pcap_t *pcap = timeout_ctx; 184 int timeout; 185 186 if (l2->num_fast_poll > 0) { 187 timeout = 20000; 188 l2->num_fast_poll--; 189 } else 190 timeout = 100000; 191 192 /* Register new timeout before calling l2_packet_receive() since 193 * receive handler may free this l2_packet instance (which will 194 * cancel this timeout). */ 195 eloop_register_timeout(0, timeout, l2_packet_receive_timeout, 196 l2, pcap); 197 pcap_dispatch(pcap, 10, l2_packet_receive_cb, (u_char *) l2); 198 } 199 #endif /* CONFIG_WINPCAP */ 200 201 202 static int l2_packet_init_libpcap(struct l2_packet_data *l2, 203 unsigned short protocol) 204 { 205 bpf_u_int32 pcap_maskp, pcap_netp; 206 char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE]; 207 struct bpf_program pcap_fp; 208 209 #ifdef CONFIG_WINPCAP 210 char ifname[128]; 211 os_snprintf(ifname, sizeof(ifname), "\\Device\\NPF_%s", l2->ifname); 212 pcap_lookupnet(ifname, &pcap_netp, &pcap_maskp, pcap_err); 213 l2->pcap = pcap_open_live(ifname, 2500, 0, 10, pcap_err); 214 if (l2->pcap == NULL) { 215 fprintf(stderr, "pcap_open_live: %s\n", pcap_err); 216 fprintf(stderr, "ifname='%s'\n", ifname); 217 return -1; 218 } 219 if (pcap_setnonblock(l2->pcap, 1, pcap_err) < 0) 220 fprintf(stderr, "pcap_setnonblock: %s\n", 221 pcap_geterr(l2->pcap)); 222 #else /* CONFIG_WINPCAP */ 223 pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err); 224 l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err); 225 if (l2->pcap == NULL) { 226 fprintf(stderr, "pcap_open_live: %s\n", pcap_err); 227 fprintf(stderr, "ifname='%s'\n", l2->ifname); 228 return -1; 229 } 230 if (pcap_datalink(l2->pcap) != DLT_EN10MB && 231 pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) { 232 fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n", 233 pcap_geterr(l2->pcap)); 234 return -1; 235 } 236 #endif /* CONFIG_WINPCAP */ 237 os_snprintf(pcap_filter, sizeof(pcap_filter), 238 "not ether src " MACSTR " and " 239 "( ether dst " MACSTR " or ether dst " MACSTR " ) and " 240 "ether proto 0x%x", 241 MAC2STR(l2->own_addr), /* do not receive own packets */ 242 MAC2STR(l2->own_addr), MAC2STR(pae_group_addr), 243 protocol); 244 if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) { 245 fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap)); 246 return -1; 247 } 248 249 if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) { 250 fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap)); 251 return -1; 252 } 253 254 pcap_freecode(&pcap_fp); 255 #ifdef BIOCIMMEDIATE 256 /* 257 * When libpcap uses BPF we must enable "immediate mode" to 258 * receive frames right away; otherwise the system may 259 * buffer them for us. 260 */ 261 { 262 unsigned int on = 1; 263 if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) { 264 fprintf(stderr, "%s: cannot enable immediate mode on " 265 "interface %s: %s\n", 266 __func__, l2->ifname, strerror(errno)); 267 /* XXX should we fail? */ 268 } 269 } 270 #endif /* BIOCIMMEDIATE */ 271 272 #ifdef CONFIG_WINPCAP 273 eloop_register_timeout(0, 100000, l2_packet_receive_timeout, 274 l2, l2->pcap); 275 #else /* CONFIG_WINPCAP */ 276 eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap), 277 l2_packet_receive, l2, l2->pcap); 278 #endif /* CONFIG_WINPCAP */ 279 280 return 0; 281 } 282 283 284 struct l2_packet_data * l2_packet_init( 285 const char *ifname, const u8 *own_addr, unsigned short protocol, 286 void (*rx_callback)(void *ctx, const u8 *src_addr, 287 const u8 *buf, size_t len), 288 void *rx_callback_ctx, int l2_hdr) 289 { 290 struct l2_packet_data *l2; 291 292 l2 = os_zalloc(sizeof(struct l2_packet_data)); 293 if (l2 == NULL) 294 return NULL; 295 os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname)); 296 l2->rx_callback = rx_callback; 297 l2->rx_callback_ctx = rx_callback_ctx; 298 l2->l2_hdr = l2_hdr; 299 300 #ifdef CONFIG_WINPCAP 301 if (own_addr) 302 os_memcpy(l2->own_addr, own_addr, ETH_ALEN); 303 #else /* CONFIG_WINPCAP */ 304 if (l2_packet_init_libdnet(l2)) 305 return NULL; 306 #endif /* CONFIG_WINPCAP */ 307 308 if (l2_packet_init_libpcap(l2, protocol)) { 309 #ifndef CONFIG_WINPCAP 310 eth_close(l2->eth); 311 #endif /* CONFIG_WINPCAP */ 312 os_free(l2); 313 return NULL; 314 } 315 316 return l2; 317 } 318 319 320 void l2_packet_deinit(struct l2_packet_data *l2) 321 { 322 if (l2 == NULL) 323 return; 324 325 #ifdef CONFIG_WINPCAP 326 eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap); 327 #else /* CONFIG_WINPCAP */ 328 if (l2->eth) 329 eth_close(l2->eth); 330 eloop_unregister_read_sock(pcap_get_selectable_fd(l2->pcap)); 331 #endif /* CONFIG_WINPCAP */ 332 if (l2->pcap) 333 pcap_close(l2->pcap); 334 os_free(l2); 335 } 336 337 338 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) 339 { 340 pcap_if_t *devs, *dev; 341 struct pcap_addr *addr; 342 struct sockaddr_in *saddr; 343 int found = 0; 344 char err[PCAP_ERRBUF_SIZE + 1]; 345 346 if (pcap_findalldevs(&devs, err) < 0) { 347 wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err); 348 return -1; 349 } 350 351 for (dev = devs; dev && !found; dev = dev->next) { 352 if (os_strcmp(dev->name, l2->ifname) != 0) 353 continue; 354 355 addr = dev->addresses; 356 while (addr) { 357 saddr = (struct sockaddr_in *) addr->addr; 358 if (saddr && saddr->sin_family == AF_INET) { 359 os_strlcpy(buf, inet_ntoa(saddr->sin_addr), 360 len); 361 found = 1; 362 break; 363 } 364 addr = addr->next; 365 } 366 } 367 368 pcap_freealldevs(devs); 369 370 return found ? 0 : -1; 371 } 372 373 374 void l2_packet_notify_auth_start(struct l2_packet_data *l2) 375 { 376 #ifdef CONFIG_WINPCAP 377 /* 378 * Use shorter poll interval for 3 seconds to reduce latency during key 379 * handshake. 380 */ 381 l2->num_fast_poll = 3 * 50; 382 eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap); 383 eloop_register_timeout(0, 10000, l2_packet_receive_timeout, 384 l2, l2->pcap); 385 #endif /* CONFIG_WINPCAP */ 386 } 387