usr.sbin/802_11/l2_packet.c

   1 /*
   2  * WPA Supplicant - Layer2 packet handling with DragonFlyBSD
   3  * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
   4  * Copyright (c) 2005, Sam Leffler <sam@errno.com>
   5  *
   6  * This software may be distributed under the terms of the BSD license.
   7  * See README for more details.
   8  */
   9
  10 #include "includes.h"
  11 #include <net/bpf.h>
  12 #include <pcap.h>
  13
  14 #include <sys/ioctl.h>
  15 #ifdef __sun__
  16 #include <libdlpi.h>
  17 #else /* __sun__ */
  18 #include <sys/sysctl.h>
  19 #endif /* __sun__ */
  20
  21 #include <net/if.h>
  22 #include <net/if_dl.h>
  23 #include <net/route.h>
  24 #include <netinet/in.h>
  25
  26 #include "common.h"
  27 #include "eloop.h"
  28 #include "l2_packet.h"
  29
  30
  31 static const u8 pae_group_addr[ETH_ALEN] =
  32 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 };
  33
  34 struct l2_packet_data {
  35         pcap_t *pcap;
  36         char ifname[100];
  37         u8 own_addr[ETH_ALEN];
  38         void (*rx_callback)(void *ctx, const u8 *src_addr,
  39                             const u8 *buf, size_t len);
  40         void *rx_callback_ctx;
  41         int l2_hdr; /* whether to include layer 2 (Ethernet) header data
  42                      * buffers */
  43 };
  44
  45
  46 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
  47 {
  48         os_memcpy(addr, l2->own_addr, ETH_ALEN);
  49         return 0;
  50 }
  51
  52
  53 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
  54                    const u8 *buf, size_t len)
  55 {
  56         if (!l2->l2_hdr) {
  57                 int ret;
  58                 struct l2_ethhdr *eth = os_malloc(sizeof(*eth) + len);
  59                 if (eth == NULL)
  60                         return -1;
  61                 os_memcpy(eth->h_dest, dst_addr, ETH_ALEN);
  62                 os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
  63                 eth->h_proto = htons(proto);
  64                 os_memcpy(eth + 1, buf, len);
  65                 ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
  66                 os_free(eth);
  67                 return ret;
  68         } else
  69                 return pcap_inject(l2->pcap, buf, len);
  70 }
  71
  72
  73 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
  74 {
  75         struct l2_packet_data *l2 = eloop_ctx;
  76         pcap_t *pcap = sock_ctx;
  77         struct pcap_pkthdr hdr;
  78         const u_char *packet;
  79         struct l2_ethhdr *ethhdr;
  80         unsigned char *buf;
  81         size_t len;
  82
  83         packet = pcap_next(pcap, &hdr);
  84
  85         if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
  86                 return;
  87
  88         ethhdr = (struct l2_ethhdr *) packet;
  89         if (l2->l2_hdr) {
  90                 buf = (unsigned char *) ethhdr;
  91                 len = hdr.caplen;
  92         } else {
  93                 buf = (unsigned char *) (ethhdr + 1);
  94                 len = hdr.caplen - sizeof(*ethhdr);
  95         }
  96         l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
  97 }
  98
  99
 100 static int l2_packet_init_libpcap(struct l2_packet_data *l2,
 101                                   unsigned short protocol)
 102 {
 103         bpf_u_int32 pcap_maskp, pcap_netp;
 104         char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE];
 105         struct bpf_program pcap_fp;
 106
 107         pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
 108         l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
 109         if (l2->pcap == NULL) {
 110                 fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
 111                 fprintf(stderr, "ifname='%s'\n", l2->ifname);
 112                 return -1;
 113         }
 114         if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
 115             pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
 116                 fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n",
 117                         pcap_geterr(l2->pcap));
 118                 return -1;
 119         }
 120         os_snprintf(pcap_filter, sizeof(pcap_filter),
 121                     "not ether src " MACSTR " and "
 122                     "( ether dst " MACSTR " or ether dst " MACSTR " ) and "
 123                     "ether proto 0x%x",
 124                     MAC2STR(l2->own_addr), /* do not receive own packets */
 125                     MAC2STR(l2->own_addr), MAC2STR(pae_group_addr),
 126                     protocol);
 127         if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
 128                 fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
 129                 return -1;
 130         }
 131
 132         if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
 133                 fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
 134                 return -1;
 135         }
 136
 137         pcap_freecode(&pcap_fp);
 138 #ifndef __sun__
 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 #endif /* __sun__ */
 154
 155         eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
 156                                  l2_packet_receive, l2, l2->pcap);
 157
 158         return 0;
 159 }
 160
 161
 162 static int eth_get(const char *device, u8 ea[ETH_ALEN])
 163 {
 164 #ifdef __sun__
 165         dlpi_handle_t dh;
 166         u32 physaddrlen = DLPI_PHYSADDR_MAX;
 167         u8 physaddr[DLPI_PHYSADDR_MAX];
 168         int retval;
 169
 170         retval = dlpi_open(device, &dh, 0);
 171         if (retval != DLPI_SUCCESS) {
 172                 wpa_printf(MSG_ERROR, "dlpi_open error: %s",
 173                            dlpi_strerror(retval));
 174                 return -1;
 175         }
 176
 177         retval = dlpi_get_physaddr(dh, DL_CURR_PHYS_ADDR, physaddr,
 178                                    &physaddrlen);
 179         if (retval != DLPI_SUCCESS) {
 180                 wpa_printf(MSG_ERROR, "dlpi_get_physaddr error: %s",
 181                            dlpi_strerror(retval));
 182                 dlpi_close(dh);
 183                 return -1;
 184         }
 185         os_memcpy(ea, physaddr, ETH_ALEN);
 186         dlpi_close(dh);
 187 #else /* __sun__ */
 188         struct if_msghdr *ifm;
 189         struct sockaddr_dl *sdl;
 190         u_char *p, *buf;
 191         size_t len;
 192         int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
 193
 194         if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
 195                 return -1;
 196         if ((buf = os_malloc(len)) == NULL)
 197                 return -1;
 198         if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
 199                 os_free(buf);
 200                 return -1;
 201         }
 202         for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
 203                 ifm = (struct if_msghdr *)p;
 204                 sdl = (struct sockaddr_dl *)(ifm + 1);
 205                 if (ifm->ifm_type != RTM_IFINFO ||
 206                     (ifm->ifm_addrs & RTA_IFP) == 0)
 207                         continue;
 208                 if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
 209                     os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
 210                         continue;
 211                 os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
 212                 break;
 213         }
 214         os_free(buf);
 215
 216         if (p >= buf + len) {
 217                 errno = ESRCH;
 218                 return -1;
 219         }
 220 #endif /* __sun__ */
 221         return 0;
 222 }
 223
 224
 225 struct l2_packet_data * l2_packet_init(
 226         const char *ifname, const u8 *own_addr, unsigned short protocol,
 227         void (*rx_callback)(void *ctx, const u8 *src_addr,
 228                             const u8 *buf, size_t len),
 229         void *rx_callback_ctx, int l2_hdr)
 230 {
 231         struct l2_packet_data *l2;
 232
 233         l2 = os_zalloc(sizeof(struct l2_packet_data));
 234         if (l2 == NULL)
 235                 return NULL;
 236         os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
 237         l2->rx_callback = rx_callback;
 238         l2->rx_callback_ctx = rx_callback_ctx;
 239         l2->l2_hdr = l2_hdr;
 240
 241         if (eth_get(l2->ifname, l2->own_addr) < 0) {
 242                 fprintf(stderr, "Failed to get link-level address for "
 243                         "interface '%s'.\n", l2->ifname);
 244                 os_free(l2);
 245                 return NULL;
 246         }
 247
 248         if (l2_packet_init_libpcap(l2, protocol)) {
 249                 os_free(l2);
 250                 return NULL;
 251         }
 252
 253         return l2;
 254 }
 255
 256
 257 void l2_packet_deinit(struct l2_packet_data *l2)
 258 {
 259         if (l2 != NULL) {
 260                 if (l2->pcap) {
 261                         eloop_unregister_read_sock(
 262                                 pcap_get_selectable_fd(l2->pcap));
 263                         pcap_close(l2->pcap);
 264                 }
 265                 os_free(l2);
 266         }
 267 }
 268
 269
 270 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
 271 {
 272         pcap_if_t *devs, *dev;
 273         struct pcap_addr *addr;
 274         struct sockaddr_in *saddr;
 275         int found = 0;
 276         char err[PCAP_ERRBUF_SIZE + 1];
 277
 278         if (pcap_findalldevs(&devs, err) < 0) {
 279                 wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
 280                 return -1;
 281         }
 282
 283         for (dev = devs; dev && !found; dev = dev->next) {
 284                 if (os_strcmp(dev->name, l2->ifname) != 0)
 285                         continue;
 286
 287                 addr = dev->addresses;
 288                 while (addr) {
 289                         saddr = (struct sockaddr_in *) addr->addr;
 290                         if (saddr && saddr->sin_family == AF_INET) {
 291                                 os_strlcpy(buf, inet_ntoa(saddr->sin_addr),
 292                                            len);
 293                                 found = 1;
 294                                 break;
 295                         }
 296                         addr = addr->next;
 297                 }
 298         }
 299
 300         pcap_freealldevs(devs);
 301
 302         return found ? 0 : -1;
 303 }
 304
 305
 306 void l2_packet_notify_auth_start(struct l2_packet_data *l2)
 307 {
 308 }