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