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
l2_packet_get_own_addr(struct l2_packet_data * l2,u8 * addr)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
l2_packet_init_libdnet(struct l2_packet_data * l2)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
l2_packet_send(struct l2_packet_data * l2,const u8 * dst_addr,u16 proto,const u8 * buf,size_t len)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
l2_packet_receive(int sock,void * eloop_ctx,void * sock_ctx)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 (!l2->rx_callback || !packet || 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
l2_packet_receive_cb(u_char * user,const struct pcap_pkthdr * hdr,const u_char * pkt_data)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 (!l2->rx_callback || !pkt_data || 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
l2_packet_receive_timeout(void * eloop_ctx,void * timeout_ctx)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
l2_packet_init_libpcap(struct l2_packet_data * l2,unsigned short protocol)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
l2_packet_init(const char * ifname,const u8 * own_addr,unsigned short protocol,void (* rx_callback)(void * ctx,const u8 * src_addr,const u8 * buf,size_t len),void * rx_callback_ctx,int l2_hdr)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
l2_packet_init_bridge(const char * br_ifname,const char * ifname,const u8 * own_addr,unsigned short protocol,void (* rx_callback)(void * ctx,const u8 * src_addr,const u8 * buf,size_t len),void * rx_callback_ctx,int l2_hdr)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
l2_packet_deinit(struct l2_packet_data * l2)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
l2_packet_get_ip_addr(struct l2_packet_data * l2,char * buf,size_t len)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
l2_packet_notify_auth_start(struct l2_packet_data * l2)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
l2_packet_set_packet_filter(struct l2_packet_data * l2,enum l2_packet_filter_type type)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