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 software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 #ifndef CONFIG_NATIVE_WINDOWS 11 #include <sys/ioctl.h> 12 #endif /* CONFIG_NATIVE_WINDOWS */ 13 #include <pcap.h> 14 #ifndef CONFIG_WINPCAP 15 #include <dnet.h> 16 #endif /* CONFIG_WINPCAP */ 17 18 #include "common.h" 19 #include "eloop.h" 20 #include "l2_packet.h" 21 22 23 static const u8 pae_group_addr[ETH_ALEN] = 24 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 }; 25 26 struct l2_packet_data { 27 pcap_t *pcap; 28 #ifdef CONFIG_WINPCAP 29 unsigned int num_fast_poll; 30 #else /* CONFIG_WINPCAP */ 31 eth_t *eth; 32 #endif /* CONFIG_WINPCAP */ 33 char ifname[100]; 34 u8 own_addr[ETH_ALEN]; 35 void (*rx_callback)(void *ctx, const u8 *src_addr, 36 const u8 *buf, size_t len); 37 void *rx_callback_ctx; 38 int l2_hdr; /* whether to include layer 2 (Ethernet) header in calls 39 * to rx_callback */ 40 }; 41 42 43 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr) 44 { 45 os_memcpy(addr, l2->own_addr, ETH_ALEN); 46 return 0; 47 } 48 49 50 #ifndef CONFIG_WINPCAP 51 static int l2_packet_init_libdnet(struct l2_packet_data *l2) 52 { 53 eth_addr_t own_addr; 54 55 l2->eth = eth_open(l2->ifname); 56 if (!l2->eth) { 57 wpa_printf(MSG_ERROR, 58 "Failed to open interface '%s' - eth_open: %s", 59 l2->ifname, strerror(errno)); 60 return -1; 61 } 62 63 if (eth_get(l2->eth, &own_addr) < 0) { 64 wpa_printf(MSG_ERROR, 65 "Failed to get own hw address from interface '%s' - eth_get: %s", 66 l2->ifname, strerror(errno)); 67 eth_close(l2->eth); 68 l2->eth = NULL; 69 return -1; 70 } 71 os_memcpy(l2->own_addr, own_addr.data, ETH_ALEN); 72 73 return 0; 74 } 75 #endif /* CONFIG_WINPCAP */ 76 77 78 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 79 const u8 *buf, size_t len) 80 { 81 int ret; 82 struct l2_ethhdr *eth; 83 84 if (l2 == NULL) 85 return -1; 86 87 if (l2->l2_hdr) { 88 #ifdef CONFIG_WINPCAP 89 ret = pcap_sendpacket(l2->pcap, buf, len); 90 #else /* CONFIG_WINPCAP */ 91 ret = eth_send(l2->eth, buf, len); 92 #endif /* CONFIG_WINPCAP */ 93 } else { 94 size_t mlen = sizeof(*eth) + len; 95 eth = os_malloc(mlen); 96 if (eth == NULL) 97 return -1; 98 99 os_memcpy(eth->h_dest, dst_addr, ETH_ALEN); 100 os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN); 101 eth->h_proto = htons(proto); 102 os_memcpy(eth + 1, buf, len); 103 104 #ifdef CONFIG_WINPCAP 105 ret = pcap_sendpacket(l2->pcap, (u8 *) eth, mlen); 106 #else /* CONFIG_WINPCAP */ 107 ret = eth_send(l2->eth, (u8 *) eth, mlen); 108 #endif /* CONFIG_WINPCAP */ 109 110 os_free(eth); 111 } 112 113 return ret; 114 } 115 116 117 #ifndef CONFIG_WINPCAP 118 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) 119 { 120 struct l2_packet_data *l2 = eloop_ctx; 121 pcap_t *pcap = sock_ctx; 122 struct pcap_pkthdr hdr; 123 const u_char *packet; 124 struct l2_ethhdr *ethhdr; 125 unsigned char *buf; 126 size_t len; 127 128 packet = pcap_next(pcap, &hdr); 129 130 if (packet == NULL || hdr.caplen < sizeof(*ethhdr)) 131 return; 132 133 ethhdr = (struct l2_ethhdr *) packet; 134 if (l2->l2_hdr) { 135 buf = (unsigned char *) ethhdr; 136 len = hdr.caplen; 137 } else { 138 buf = (unsigned char *) (ethhdr + 1); 139 len = hdr.caplen - sizeof(*ethhdr); 140 } 141 l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len); 142 } 143 #endif /* CONFIG_WINPCAP */ 144 145 146 #ifdef CONFIG_WINPCAP 147 static void l2_packet_receive_cb(u_char *user, const struct pcap_pkthdr *hdr, 148 const u_char *pkt_data) 149 { 150 struct l2_packet_data *l2 = (struct l2_packet_data *) user; 151 struct l2_ethhdr *ethhdr; 152 unsigned char *buf; 153 size_t len; 154 155 if (pkt_data == NULL || hdr->caplen < sizeof(*ethhdr)) 156 return; 157 158 ethhdr = (struct l2_ethhdr *) pkt_data; 159 if (l2->l2_hdr) { 160 buf = (unsigned char *) ethhdr; 161 len = hdr->caplen; 162 } else { 163 buf = (unsigned char *) (ethhdr + 1); 164 len = hdr->caplen - sizeof(*ethhdr); 165 } 166 l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len); 167 /* 168 * Use shorter poll interval for 3 seconds to reduce latency during key 169 * handshake. 170 */ 171 l2->num_fast_poll = 3 * 50; 172 } 173 174 175 static void l2_packet_receive_timeout(void *eloop_ctx, void *timeout_ctx) 176 { 177 struct l2_packet_data *l2 = eloop_ctx; 178 pcap_t *pcap = timeout_ctx; 179 int timeout; 180 181 if (l2->num_fast_poll > 0) { 182 timeout = 20000; 183 l2->num_fast_poll--; 184 } else 185 timeout = 100000; 186 187 /* Register new timeout before calling l2_packet_receive() since 188 * receive handler may free this l2_packet instance (which will 189 * cancel this timeout). */ 190 eloop_register_timeout(0, timeout, l2_packet_receive_timeout, 191 l2, pcap); 192 pcap_dispatch(pcap, 10, l2_packet_receive_cb, (u_char *) l2); 193 } 194 #endif /* CONFIG_WINPCAP */ 195 196 197 static int l2_packet_init_libpcap(struct l2_packet_data *l2, 198 unsigned short protocol) 199 { 200 bpf_u_int32 pcap_maskp, pcap_netp; 201 char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE]; 202 struct bpf_program pcap_fp; 203 204 #ifdef CONFIG_WINPCAP 205 char ifname[128]; 206 os_snprintf(ifname, sizeof(ifname), "\\Device\\NPF_%s", l2->ifname); 207 pcap_lookupnet(ifname, &pcap_netp, &pcap_maskp, pcap_err); 208 l2->pcap = pcap_open_live(ifname, 2500, 0, 10, pcap_err); 209 if (l2->pcap == NULL) { 210 fprintf(stderr, "pcap_open_live: %s\n", pcap_err); 211 fprintf(stderr, "ifname='%s'\n", ifname); 212 return -1; 213 } 214 if (pcap_setnonblock(l2->pcap, 1, pcap_err) < 0) 215 fprintf(stderr, "pcap_setnonblock: %s\n", 216 pcap_geterr(l2->pcap)); 217 #else /* CONFIG_WINPCAP */ 218 pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err); 219 l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err); 220 if (l2->pcap == NULL) { 221 fprintf(stderr, "pcap_open_live: %s\n", pcap_err); 222 fprintf(stderr, "ifname='%s'\n", l2->ifname); 223 return -1; 224 } 225 if (pcap_datalink(l2->pcap) != DLT_EN10MB && 226 pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) { 227 fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n", 228 pcap_geterr(l2->pcap)); 229 return -1; 230 } 231 #endif /* CONFIG_WINPCAP */ 232 os_snprintf(pcap_filter, sizeof(pcap_filter), 233 "not ether src " MACSTR " and " 234 "( ether dst " MACSTR " or ether dst " MACSTR " ) and " 235 "ether proto 0x%x", 236 MAC2STR(l2->own_addr), /* do not receive own packets */ 237 MAC2STR(l2->own_addr), MAC2STR(pae_group_addr), 238 protocol); 239 if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) { 240 fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap)); 241 return -1; 242 } 243 244 if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) { 245 fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap)); 246 return -1; 247 } 248 249 pcap_freecode(&pcap_fp); 250 #ifdef BIOCIMMEDIATE 251 /* 252 * When libpcap uses BPF we must enable "immediate mode" to 253 * receive frames right away; otherwise the system may 254 * buffer them for us. 255 */ 256 { 257 unsigned int on = 1; 258 if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) { 259 fprintf(stderr, "%s: cannot enable immediate mode on " 260 "interface %s: %s\n", 261 __func__, l2->ifname, strerror(errno)); 262 /* XXX should we fail? */ 263 } 264 } 265 #endif /* BIOCIMMEDIATE */ 266 267 #ifdef CONFIG_WINPCAP 268 eloop_register_timeout(0, 100000, l2_packet_receive_timeout, 269 l2, l2->pcap); 270 #else /* CONFIG_WINPCAP */ 271 eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap), 272 l2_packet_receive, l2, l2->pcap); 273 #endif /* CONFIG_WINPCAP */ 274 275 return 0; 276 } 277 278 279 struct l2_packet_data * l2_packet_init( 280 const char *ifname, const u8 *own_addr, unsigned short protocol, 281 void (*rx_callback)(void *ctx, const u8 *src_addr, 282 const u8 *buf, size_t len), 283 void *rx_callback_ctx, int l2_hdr) 284 { 285 struct l2_packet_data *l2; 286 287 l2 = os_zalloc(sizeof(struct l2_packet_data)); 288 if (l2 == NULL) 289 return NULL; 290 os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname)); 291 l2->rx_callback = rx_callback; 292 l2->rx_callback_ctx = rx_callback_ctx; 293 l2->l2_hdr = l2_hdr; 294 295 #ifdef CONFIG_WINPCAP 296 if (own_addr) 297 os_memcpy(l2->own_addr, own_addr, ETH_ALEN); 298 #else /* CONFIG_WINPCAP */ 299 if (l2_packet_init_libdnet(l2)) 300 return NULL; 301 #endif /* CONFIG_WINPCAP */ 302 303 if (l2_packet_init_libpcap(l2, protocol)) { 304 #ifndef CONFIG_WINPCAP 305 eth_close(l2->eth); 306 #endif /* CONFIG_WINPCAP */ 307 os_free(l2); 308 return NULL; 309 } 310 311 return l2; 312 } 313 314 315 struct l2_packet_data * l2_packet_init_bridge( 316 const char *br_ifname, const char *ifname, const u8 *own_addr, 317 unsigned short protocol, 318 void (*rx_callback)(void *ctx, const u8 *src_addr, 319 const u8 *buf, size_t len), 320 void *rx_callback_ctx, int l2_hdr) 321 { 322 return l2_packet_init(br_ifname, own_addr, protocol, rx_callback, 323 rx_callback_ctx, l2_hdr); 324 } 325 326 327 void l2_packet_deinit(struct l2_packet_data *l2) 328 { 329 if (l2 == NULL) 330 return; 331 332 #ifdef CONFIG_WINPCAP 333 eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap); 334 #else /* CONFIG_WINPCAP */ 335 if (l2->eth) 336 eth_close(l2->eth); 337 eloop_unregister_read_sock(pcap_get_selectable_fd(l2->pcap)); 338 #endif /* CONFIG_WINPCAP */ 339 if (l2->pcap) 340 pcap_close(l2->pcap); 341 os_free(l2); 342 } 343 344 345 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) 346 { 347 pcap_if_t *devs, *dev; 348 struct pcap_addr *addr; 349 struct sockaddr_in *saddr; 350 int found = 0; 351 char err[PCAP_ERRBUF_SIZE + 1]; 352 353 if (pcap_findalldevs(&devs, err) < 0) { 354 wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err); 355 return -1; 356 } 357 358 for (dev = devs; dev && !found; dev = dev->next) { 359 if (os_strcmp(dev->name, l2->ifname) != 0) 360 continue; 361 362 addr = dev->addresses; 363 while (addr) { 364 saddr = (struct sockaddr_in *) addr->addr; 365 if (saddr && saddr->sin_family == AF_INET) { 366 os_strlcpy(buf, inet_ntoa(saddr->sin_addr), 367 len); 368 found = 1; 369 break; 370 } 371 addr = addr->next; 372 } 373 } 374 375 pcap_freealldevs(devs); 376 377 return found ? 0 : -1; 378 } 379 380 381 void l2_packet_notify_auth_start(struct l2_packet_data *l2) 382 { 383 #ifdef CONFIG_WINPCAP 384 /* 385 * Use shorter poll interval for 3 seconds to reduce latency during key 386 * handshake. 387 */ 388 l2->num_fast_poll = 3 * 50; 389 eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap); 390 eloop_register_timeout(0, 10000, l2_packet_receive_timeout, 391 l2, l2->pcap); 392 #endif /* CONFIG_WINPCAP */ 393 } 394 395 396 int l2_packet_set_packet_filter(struct l2_packet_data *l2, 397 enum l2_packet_filter_type type) 398 { 399 return -1; 400 } 401