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 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 <sys/param.h>
12 #if defined(__APPLE__) || defined(__GLIBC__) || defined(__FreeBSD_version)
13 #include <net/bpf.h>
14 #endif /* __APPLE__ */
15 #include <pcap.h>
16 
17 #include <sys/ioctl.h>
18 #ifdef __sun__
19 #include <libdlpi.h>
20 #else /* __sun__ */
21 #include <sys/sysctl.h>
22 #endif /* __sun__ */
23 
24 #include <net/if.h>
25 #include <net/if_dl.h>
26 #include <net/route.h>
27 #include <netinet/in.h>
28 
29 #include "common.h"
30 #include "eloop.h"
31 #include "l2_packet.h"
32 
33 
34 static const u8 pae_group_addr[ETH_ALEN] =
35 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 };
36 
37 struct l2_packet_data {
38 	pcap_t *pcap;
39 	char ifname[100];
40 	u8 own_addr[ETH_ALEN];
41 	void (*rx_callback)(void *ctx, const u8 *src_addr,
42 			    const u8 *buf, size_t len);
43 	void *rx_callback_ctx;
44 	int l2_hdr; /* whether to include layer 2 (Ethernet) header data
45 		     * buffers */
46 };
47 
48 
49 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
50 {
51 	os_memcpy(addr, l2->own_addr, ETH_ALEN);
52 	return 0;
53 }
54 
55 
56 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
57 		   const u8 *buf, size_t len)
58 {
59 	if (!l2->l2_hdr) {
60 		int ret;
61 		struct l2_ethhdr *eth = os_malloc(sizeof(*eth) + len);
62 		if (eth == NULL)
63 			return -1;
64 		os_memcpy(eth->h_dest, dst_addr, ETH_ALEN);
65 		os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
66 		eth->h_proto = htons(proto);
67 		os_memcpy(eth + 1, buf, len);
68 		ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
69 		os_free(eth);
70 		return ret;
71 	} else
72 		return pcap_inject(l2->pcap, buf, len);
73 }
74 
75 
76 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
77 {
78 	struct l2_packet_data *l2 = eloop_ctx;
79 	pcap_t *pcap = sock_ctx;
80 	struct pcap_pkthdr *hdr;
81 	const u_char *packet;
82 	struct l2_ethhdr *ethhdr;
83 	unsigned char *buf;
84 	size_t len;
85 
86 	if (pcap_next_ex(pcap, &hdr, &packet) == -1) {
87 		wpa_printf(MSG_ERROR, "Error reading packet, has device disappeared?");
88 		eloop_terminate();
89 	}
90 
91 	if (!l2->rx_callback || !packet || hdr->caplen < sizeof(*ethhdr))
92 		return;
93 
94 	ethhdr = (struct l2_ethhdr *) packet;
95 	if (l2->l2_hdr) {
96 		buf = (unsigned char *) ethhdr;
97 		len = hdr->caplen;
98 	} else {
99 		buf = (unsigned char *) (ethhdr + 1);
100 		len = hdr->caplen - sizeof(*ethhdr);
101 	}
102 	l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
103 }
104 
105 
106 static int l2_packet_init_libpcap(struct l2_packet_data *l2,
107 				  unsigned short protocol)
108 {
109 	bpf_u_int32 pcap_maskp, pcap_netp;
110 	char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE];
111 	struct bpf_program pcap_fp;
112 
113 	pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
114 	l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
115 	if (l2->pcap == NULL) {
116 		fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
117 		fprintf(stderr, "ifname='%s'\n", l2->ifname);
118 		return -1;
119 	}
120 	if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
121 	    pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
122 		fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n",
123 			pcap_geterr(l2->pcap));
124 		return -1;
125 	}
126 	os_snprintf(pcap_filter, sizeof(pcap_filter),
127 		    "not ether src " MACSTR " and "
128 		    "( ether dst " MACSTR " or ether dst " MACSTR " ) and "
129 		    "ether proto 0x%x",
130 		    MAC2STR(l2->own_addr), /* do not receive own packets */
131 		    MAC2STR(l2->own_addr), MAC2STR(pae_group_addr),
132 		    protocol);
133 	if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
134 		fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
135 		return -1;
136 	}
137 
138 	if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
139 		fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
140 		return -1;
141 	}
142 
143 	pcap_freecode(&pcap_fp);
144 #ifndef __sun__
145 	/*
146 	 * When libpcap uses BPF we must enable "immediate mode" to
147 	 * receive frames right away; otherwise the system may
148 	 * buffer them for us.
149 	 */
150 	{
151 		unsigned int on = 1;
152 		if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) {
153 			fprintf(stderr, "%s: cannot enable immediate mode on "
154 				"interface %s: %s\n",
155 				__func__, l2->ifname, strerror(errno));
156 			/* XXX should we fail? */
157 		}
158 	}
159 #endif /* __sun__ */
160 
161 	eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
162 				 l2_packet_receive, l2, l2->pcap);
163 
164 	return 0;
165 }
166 
167 
168 static int eth_get(const char *device, u8 ea[ETH_ALEN])
169 {
170 #ifdef __sun__
171 	dlpi_handle_t dh;
172 	u32 physaddrlen = DLPI_PHYSADDR_MAX;
173 	u8 physaddr[DLPI_PHYSADDR_MAX];
174 	int retval;
175 
176 	retval = dlpi_open(device, &dh, 0);
177 	if (retval != DLPI_SUCCESS) {
178 		wpa_printf(MSG_ERROR, "dlpi_open error: %s",
179 			   dlpi_strerror(retval));
180 		return -1;
181 	}
182 
183 	retval = dlpi_get_physaddr(dh, DL_CURR_PHYS_ADDR, physaddr,
184 				   &physaddrlen);
185 	if (retval != DLPI_SUCCESS) {
186 		wpa_printf(MSG_ERROR, "dlpi_get_physaddr error: %s",
187 			   dlpi_strerror(retval));
188 		dlpi_close(dh);
189 		return -1;
190 	}
191 	os_memcpy(ea, physaddr, ETH_ALEN);
192 	dlpi_close(dh);
193 #else /* __sun__ */
194 	struct if_msghdr *ifm;
195 	struct sockaddr_dl *sdl;
196 	u_char *p, *buf;
197 	size_t len;
198 	int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
199 
200 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
201 		return -1;
202 	if ((buf = os_malloc(len)) == NULL)
203 		return -1;
204 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
205 		os_free(buf);
206 		return -1;
207 	}
208 	for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
209 		ifm = (struct if_msghdr *)p;
210 		sdl = (struct sockaddr_dl *)(ifm + 1);
211 		if (ifm->ifm_type != RTM_IFINFO ||
212 		    (ifm->ifm_addrs & RTA_IFP) == 0)
213 			continue;
214 		if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
215 		    os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
216 			continue;
217 		os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
218 		break;
219 	}
220 	os_free(buf);
221 
222 	if (p >= buf + len) {
223 		errno = ESRCH;
224 		return -1;
225 	}
226 #endif /* __sun__ */
227 	return 0;
228 }
229 
230 
231 struct l2_packet_data * l2_packet_init(
232 	const char *ifname, const u8 *own_addr, unsigned short protocol,
233 	void (*rx_callback)(void *ctx, const u8 *src_addr,
234 			    const u8 *buf, size_t len),
235 	void *rx_callback_ctx, int l2_hdr)
236 {
237 	struct l2_packet_data *l2;
238 
239 	l2 = os_zalloc(sizeof(struct l2_packet_data));
240 	if (l2 == NULL)
241 		return NULL;
242 	os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
243 	l2->rx_callback = rx_callback;
244 	l2->rx_callback_ctx = rx_callback_ctx;
245 	l2->l2_hdr = l2_hdr;
246 
247 	if (eth_get(l2->ifname, l2->own_addr) < 0) {
248 		fprintf(stderr, "Failed to get link-level address for "
249 			"interface '%s'.\n", l2->ifname);
250 		os_free(l2);
251 		return NULL;
252 	}
253 
254 	if (l2_packet_init_libpcap(l2, protocol)) {
255 		os_free(l2);
256 		return NULL;
257 	}
258 
259 	return l2;
260 }
261 
262 
263 struct l2_packet_data * l2_packet_init_bridge(
264 	const char *br_ifname, const char *ifname, const u8 *own_addr,
265 	unsigned short protocol,
266 	void (*rx_callback)(void *ctx, const u8 *src_addr,
267 			    const u8 *buf, size_t len),
268 	void *rx_callback_ctx, int l2_hdr)
269 {
270 	return l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
271 			      rx_callback_ctx, l2_hdr);
272 }
273 
274 
275 void l2_packet_deinit(struct l2_packet_data *l2)
276 {
277 	if (l2 != NULL) {
278 		if (l2->pcap) {
279 			eloop_unregister_read_sock(
280 				pcap_get_selectable_fd(l2->pcap));
281 			pcap_close(l2->pcap);
282 		}
283 		os_free(l2);
284 	}
285 }
286 
287 
288 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
289 {
290 	pcap_if_t *devs, *dev;
291 	struct pcap_addr *addr;
292 	struct sockaddr_in *saddr;
293 	int found = 0;
294 	char err[PCAP_ERRBUF_SIZE + 1];
295 
296 	if (pcap_findalldevs(&devs, err) < 0) {
297 		wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
298 		return -1;
299 	}
300 
301 	for (dev = devs; dev && !found; dev = dev->next) {
302 		if (os_strcmp(dev->name, l2->ifname) != 0)
303 			continue;
304 
305 		addr = dev->addresses;
306 		while (addr) {
307 			saddr = (struct sockaddr_in *) addr->addr;
308 			if (saddr && saddr->sin_family == AF_INET) {
309 				os_strlcpy(buf, inet_ntoa(saddr->sin_addr),
310 					   len);
311 				found = 1;
312 				break;
313 			}
314 			addr = addr->next;
315 		}
316 	}
317 
318 	pcap_freealldevs(devs);
319 
320 	return found ? 0 : -1;
321 }
322 
323 
324 void l2_packet_notify_auth_start(struct l2_packet_data *l2)
325 {
326 }
327 
328 
329 int l2_packet_set_packet_filter(struct l2_packet_data *l2,
330 				enum l2_packet_filter_type type)
331 {
332 	return -1;
333 }
334