1 /* 2 * WPA Supplicant - Layer2 packet handling with FreeBSD 3 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> 4 * Copyright (c) 2005, Sam Leffler <sam@errno.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Alternatively, this software may be distributed under the terms of BSD 11 * license. 12 * 13 * See README and COPYING for more details. 14 */ 15 16 #include "includes.h" 17 #if defined(__APPLE__) || defined(__GLIBC__) 18 #include <net/bpf.h> 19 #endif /* __APPLE__ */ 20 #include <pcap.h> 21 22 #include <sys/ioctl.h> 23 #include <sys/sysctl.h> 24 25 #include <net/if.h> 26 #include <net/if_dl.h> 27 #include <net/route.h> 28 #include <netinet/in.h> 29 30 #include "common.h" 31 #include "eloop.h" 32 #include "l2_packet.h" 33 34 35 static const u8 pae_group_addr[ETH_ALEN] = 36 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 }; 37 38 struct l2_packet_data { 39 pcap_t *pcap; 40 char ifname[100]; 41 u8 own_addr[ETH_ALEN]; 42 void (*rx_callback)(void *ctx, const u8 *src_addr, 43 const u8 *buf, size_t len); 44 void *rx_callback_ctx; 45 int l2_hdr; /* whether to include layer 2 (Ethernet) header data 46 * buffers */ 47 }; 48 49 50 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr) 51 { 52 os_memcpy(addr, l2->own_addr, ETH_ALEN); 53 return 0; 54 } 55 56 57 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 58 const u8 *buf, size_t len) 59 { 60 if (!l2->l2_hdr) { 61 int ret; 62 struct l2_ethhdr *eth = os_malloc(sizeof(*eth) + len); 63 if (eth == NULL) 64 return -1; 65 os_memcpy(eth->h_dest, dst_addr, ETH_ALEN); 66 os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN); 67 eth->h_proto = htons(proto); 68 os_memcpy(eth + 1, buf, len); 69 ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth)); 70 os_free(eth); 71 return ret; 72 } else 73 return pcap_inject(l2->pcap, buf, len); 74 } 75 76 77 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) 78 { 79 struct l2_packet_data *l2 = eloop_ctx; 80 pcap_t *pcap = sock_ctx; 81 struct pcap_pkthdr hdr; 82 const u_char *packet; 83 struct l2_ethhdr *ethhdr; 84 unsigned char *buf; 85 size_t len; 86 87 packet = pcap_next(pcap, &hdr); 88 89 if (packet == NULL || hdr.caplen < sizeof(*ethhdr)) 90 return; 91 92 ethhdr = (struct l2_ethhdr *) packet; 93 if (l2->l2_hdr) { 94 buf = (unsigned char *) ethhdr; 95 len = hdr.caplen; 96 } else { 97 buf = (unsigned char *) (ethhdr + 1); 98 len = hdr.caplen - sizeof(*ethhdr); 99 } 100 l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len); 101 } 102 103 104 static int l2_packet_init_libpcap(struct l2_packet_data *l2, 105 unsigned short protocol) 106 { 107 bpf_u_int32 pcap_maskp, pcap_netp; 108 char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE]; 109 struct bpf_program pcap_fp; 110 111 pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err); 112 l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err); 113 if (l2->pcap == NULL) { 114 fprintf(stderr, "pcap_open_live: %s\n", pcap_err); 115 fprintf(stderr, "ifname='%s'\n", l2->ifname); 116 return -1; 117 } 118 if (pcap_datalink(l2->pcap) != DLT_EN10MB && 119 pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) { 120 fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n", 121 pcap_geterr(l2->pcap)); 122 return -1; 123 } 124 os_snprintf(pcap_filter, sizeof(pcap_filter), 125 "not ether src " MACSTR " and " 126 "( ether dst " MACSTR " or ether dst " MACSTR " ) and " 127 "ether proto 0x%x", 128 MAC2STR(l2->own_addr), /* do not receive own packets */ 129 MAC2STR(l2->own_addr), MAC2STR(pae_group_addr), 130 protocol); 131 if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) { 132 fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap)); 133 return -1; 134 } 135 136 if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) { 137 fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap)); 138 return -1; 139 } 140 141 pcap_freecode(&pcap_fp); 142 /* 143 * When libpcap uses BPF we must enable "immediate mode" to 144 * receive frames right away; otherwise the system may 145 * buffer them for us. 146 */ 147 { 148 unsigned int on = 1; 149 if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) { 150 fprintf(stderr, "%s: cannot enable immediate mode on " 151 "interface %s: %s\n", 152 __func__, l2->ifname, strerror(errno)); 153 /* XXX should we fail? */ 154 } 155 } 156 157 eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap), 158 l2_packet_receive, l2, l2->pcap); 159 160 return 0; 161 } 162 163 164 static int eth_get(const char *device, u8 ea[ETH_ALEN]) 165 { 166 struct if_msghdr *ifm; 167 struct sockaddr_dl *sdl; 168 u_char *p, *buf; 169 size_t len; 170 int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 }; 171 172 if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) 173 return -1; 174 if ((buf = os_malloc(len)) == NULL) 175 return -1; 176 if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) { 177 os_free(buf); 178 return -1; 179 } 180 for (p = buf; p < buf + len; p += ifm->ifm_msglen) { 181 ifm = (struct if_msghdr *)p; 182 sdl = (struct sockaddr_dl *)(ifm + 1); 183 if (ifm->ifm_type != RTM_IFINFO || 184 (ifm->ifm_addrs & RTA_IFP) == 0) 185 continue; 186 if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 || 187 os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0) 188 continue; 189 os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen); 190 break; 191 } 192 os_free(buf); 193 194 if (p >= buf + len) { 195 errno = ESRCH; 196 return -1; 197 } 198 return 0; 199 } 200 201 202 struct l2_packet_data * l2_packet_init( 203 const char *ifname, const u8 *own_addr, unsigned short protocol, 204 void (*rx_callback)(void *ctx, const u8 *src_addr, 205 const u8 *buf, size_t len), 206 void *rx_callback_ctx, int l2_hdr) 207 { 208 struct l2_packet_data *l2; 209 210 l2 = os_zalloc(sizeof(struct l2_packet_data)); 211 if (l2 == NULL) 212 return NULL; 213 os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname)); 214 l2->rx_callback = rx_callback; 215 l2->rx_callback_ctx = rx_callback_ctx; 216 l2->l2_hdr = l2_hdr; 217 218 if (eth_get(l2->ifname, l2->own_addr) < 0) { 219 fprintf(stderr, "Failed to get link-level address for " 220 "interface '%s'.\n", l2->ifname); 221 os_free(l2); 222 return NULL; 223 } 224 225 if (l2_packet_init_libpcap(l2, protocol)) { 226 os_free(l2); 227 return NULL; 228 } 229 230 return l2; 231 } 232 233 234 void l2_packet_deinit(struct l2_packet_data *l2) 235 { 236 if (l2 != NULL) { 237 if (l2->pcap) { 238 eloop_unregister_read_sock( 239 pcap_get_selectable_fd(l2->pcap)); 240 pcap_close(l2->pcap); 241 } 242 os_free(l2); 243 } 244 } 245 246 247 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) 248 { 249 pcap_if_t *devs, *dev; 250 struct pcap_addr *addr; 251 struct sockaddr_in *saddr; 252 int found = 0; 253 char err[PCAP_ERRBUF_SIZE + 1]; 254 255 if (pcap_findalldevs(&devs, err) < 0) { 256 wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err); 257 return -1; 258 } 259 260 for (dev = devs; dev && !found; dev = dev->next) { 261 if (os_strcmp(dev->name, l2->ifname) != 0) 262 continue; 263 264 addr = dev->addresses; 265 while (addr) { 266 saddr = (struct sockaddr_in *) addr->addr; 267 if (saddr && saddr->sin_family == AF_INET) { 268 os_strlcpy(buf, inet_ntoa(saddr->sin_addr), 269 len); 270 found = 1; 271 break; 272 } 273 addr = addr->next; 274 } 275 } 276 277 pcap_freealldevs(devs); 278 279 return found ? 0 : -1; 280 } 281 282 283 void l2_packet_notify_auth_start(struct l2_packet_data *l2) 284 { 285 } 286