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(__DragonFly__)
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 	packet = pcap_next(pcap, &hdr);
87 
88 	if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
89 		return;
90 
91 	ethhdr = (struct l2_ethhdr *) packet;
92 	if (l2->l2_hdr) {
93 		buf = (unsigned char *) ethhdr;
94 		len = hdr.caplen;
95 	} else {
96 		buf = (unsigned char *) (ethhdr + 1);
97 		len = hdr.caplen - sizeof(*ethhdr);
98 	}
99 	l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
100 }
101 
102 
103 static int l2_packet_init_libpcap(struct l2_packet_data *l2,
104 				  unsigned short protocol)
105 {
106 	bpf_u_int32 pcap_maskp, pcap_netp;
107 	char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE];
108 	struct bpf_program pcap_fp;
109 
110 	pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
111 	l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
112 	if (l2->pcap == NULL) {
113 		fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
114 		fprintf(stderr, "ifname='%s'\n", l2->ifname);
115 		return -1;
116 	}
117 	if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
118 	    pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
119 		fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n",
120 			pcap_geterr(l2->pcap));
121 		return -1;
122 	}
123 	os_snprintf(pcap_filter, sizeof(pcap_filter),
124 		    "not ether src " MACSTR " and "
125 		    "( ether dst " MACSTR " or ether dst " MACSTR " ) and "
126 		    "ether proto 0x%x",
127 		    MAC2STR(l2->own_addr), /* do not receive own packets */
128 		    MAC2STR(l2->own_addr), MAC2STR(pae_group_addr),
129 		    protocol);
130 	if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
131 		fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
132 		return -1;
133 	}
134 
135 	if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
136 		fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
137 		return -1;
138 	}
139 
140 	pcap_freecode(&pcap_fp);
141 #ifndef __sun__
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 #endif /* __sun__ */
157 
158 	eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
159 				 l2_packet_receive, l2, l2->pcap);
160 
161 	return 0;
162 }
163 
164 
165 static int eth_get(const char *device, u8 ea[ETH_ALEN])
166 {
167 #ifdef __sun__
168 	dlpi_handle_t dh;
169 	u32 physaddrlen = DLPI_PHYSADDR_MAX;
170 	u8 physaddr[DLPI_PHYSADDR_MAX];
171 	int retval;
172 
173 	retval = dlpi_open(device, &dh, 0);
174 	if (retval != DLPI_SUCCESS) {
175 		wpa_printf(MSG_ERROR, "dlpi_open error: %s",
176 			   dlpi_strerror(retval));
177 		return -1;
178 	}
179 
180 	retval = dlpi_get_physaddr(dh, DL_CURR_PHYS_ADDR, physaddr,
181 				   &physaddrlen);
182 	if (retval != DLPI_SUCCESS) {
183 		wpa_printf(MSG_ERROR, "dlpi_get_physaddr error: %s",
184 			   dlpi_strerror(retval));
185 		dlpi_close(dh);
186 		return -1;
187 	}
188 	os_memcpy(ea, physaddr, ETH_ALEN);
189 	dlpi_close(dh);
190 #else /* __sun__ */
191 	struct if_msghdr *ifm;
192 	struct sockaddr_dl *sdl;
193 	u_char *p, *buf;
194 	size_t len;
195 	int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
196 
197 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
198 		return -1;
199 	if ((buf = os_malloc(len)) == NULL)
200 		return -1;
201 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
202 		os_free(buf);
203 		return -1;
204 	}
205 	for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
206 		ifm = (struct if_msghdr *)p;
207 		sdl = (struct sockaddr_dl *)(ifm + 1);
208 		if (ifm->ifm_type != RTM_IFINFO ||
209 		    (ifm->ifm_addrs & RTA_IFP) == 0)
210 			continue;
211 		if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
212 		    os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
213 			continue;
214 		os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
215 		break;
216 	}
217 	os_free(buf);
218 
219 	if (p >= buf + len) {
220 		errno = ESRCH;
221 		return -1;
222 	}
223 #endif /* __sun__ */
224 	return 0;
225 }
226 
227 
228 struct l2_packet_data * l2_packet_init(
229 	const char *ifname, const u8 *own_addr, unsigned short protocol,
230 	void (*rx_callback)(void *ctx, const u8 *src_addr,
231 			    const u8 *buf, size_t len),
232 	void *rx_callback_ctx, int l2_hdr)
233 {
234 	struct l2_packet_data *l2;
235 
236 	l2 = os_zalloc(sizeof(struct l2_packet_data));
237 	if (l2 == NULL)
238 		return NULL;
239 	os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
240 	l2->rx_callback = rx_callback;
241 	l2->rx_callback_ctx = rx_callback_ctx;
242 	l2->l2_hdr = l2_hdr;
243 
244 	if (eth_get(l2->ifname, l2->own_addr) < 0) {
245 		fprintf(stderr, "Failed to get link-level address for "
246 			"interface '%s'.\n", l2->ifname);
247 		os_free(l2);
248 		return NULL;
249 	}
250 
251 	if (l2_packet_init_libpcap(l2, protocol)) {
252 		os_free(l2);
253 		return NULL;
254 	}
255 
256 	return l2;
257 }
258 
259 
260 struct l2_packet_data * l2_packet_init_bridge(
261 	const char *br_ifname, const char *ifname, const u8 *own_addr,
262 	unsigned short protocol,
263 	void (*rx_callback)(void *ctx, const u8 *src_addr,
264 			    const u8 *buf, size_t len),
265 	void *rx_callback_ctx, int l2_hdr)
266 {
267 	return l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
268 			      rx_callback_ctx, l2_hdr);
269 }
270 
271 
272 void l2_packet_deinit(struct l2_packet_data *l2)
273 {
274 	if (l2 != NULL) {
275 		if (l2->pcap) {
276 			eloop_unregister_read_sock(
277 				pcap_get_selectable_fd(l2->pcap));
278 			pcap_close(l2->pcap);
279 		}
280 		os_free(l2);
281 	}
282 }
283 
284 
285 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
286 {
287 	pcap_if_t *devs, *dev;
288 	struct pcap_addr *addr;
289 	struct sockaddr_in *saddr;
290 	int found = 0;
291 	char err[PCAP_ERRBUF_SIZE + 1];
292 
293 	if (pcap_findalldevs(&devs, err) < 0) {
294 		wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
295 		return -1;
296 	}
297 
298 	for (dev = devs; dev && !found; dev = dev->next) {
299 		if (os_strcmp(dev->name, l2->ifname) != 0)
300 			continue;
301 
302 		addr = dev->addresses;
303 		while (addr) {
304 			saddr = (struct sockaddr_in *) addr->addr;
305 			if (saddr && saddr->sin_family == AF_INET) {
306 				os_strlcpy(buf, inet_ntoa(saddr->sin_addr),
307 					   len);
308 				found = 1;
309 				break;
310 			}
311 			addr = addr->next;
312 		}
313 	}
314 
315 	pcap_freealldevs(devs);
316 
317 	return found ? 0 : -1;
318 }
319 
320 
321 void l2_packet_notify_auth_start(struct l2_packet_data *l2)
322 {
323 }
324 
325 
326 int l2_packet_set_packet_filter(struct l2_packet_data *l2,
327 				enum l2_packet_filter_type type)
328 {
329 	return -1;
330 }
331