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