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 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#if defined(__APPLE__) || defined(__GLIBC__) || defined(__NetBSD__)
18#include <net/bpf.h>
19#endif /* __APPLE__ */
20#include <pcap.h>
21
22#include <sys/ioctl.h>
23#include <sys/sysctl.h>
24
25#include <net/if.h>
26#include <net/if_dl.h>
27#include <net/route.h>
28#include <netinet/in.h>
29
30#include "common.h"
31#include "eloop.h"
32#include "l2_packet.h"
33
34
35static const u8 pae_group_addr[ETH_ALEN] =
36{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 };
37
38struct l2_packet_data {
39	pcap_t *pcap;
40	char ifname[100];
41	u8 own_addr[ETH_ALEN];
42	void (*rx_callback)(void *ctx, const u8 *src_addr,
43			    const u8 *buf, size_t len);
44	void *rx_callback_ctx;
45	int l2_hdr; /* whether to include layer 2 (Ethernet) header data
46		     * buffers */
47};
48
49
50int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
51{
52	os_memcpy(addr, l2->own_addr, ETH_ALEN);
53	return 0;
54}
55
56
57int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
58		   const u8 *buf, size_t len)
59{
60	if (!l2->l2_hdr) {
61		int ret;
62		struct l2_ethhdr *eth = os_malloc(sizeof(*eth) + len);
63		if (eth == NULL)
64			return -1;
65		os_memcpy(eth->h_dest, dst_addr, ETH_ALEN);
66		os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
67		eth->h_proto = htons(proto);
68		os_memcpy(eth + 1, buf, len);
69		ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
70		os_free(eth);
71		return ret;
72	} else
73		return pcap_inject(l2->pcap, buf, len);
74}
75
76
77static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
78{
79	struct l2_packet_data *l2 = eloop_ctx;
80	pcap_t *pcap = sock_ctx;
81	struct pcap_pkthdr hdr;
82	const u_char *packet;
83	struct l2_ethhdr *ethhdr;
84	unsigned char *buf;
85	size_t len;
86
87	packet = pcap_next(pcap, &hdr);
88
89	if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
90		return;
91
92	ethhdr = (struct l2_ethhdr *) packet;
93	if (l2->l2_hdr) {
94		buf = (unsigned char *) ethhdr;
95		len = hdr.caplen;
96	} else {
97		buf = (unsigned char *) (ethhdr + 1);
98		len = hdr.caplen - sizeof(*ethhdr);
99	}
100	l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
101}
102
103
104static int l2_packet_init_libpcap(struct l2_packet_data *l2,
105				  unsigned short protocol)
106{
107	bpf_u_int32 pcap_maskp, pcap_netp;
108	char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE];
109	struct bpf_program pcap_fp;
110
111	pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
112	l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
113	if (l2->pcap == NULL) {
114		fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
115		fprintf(stderr, "ifname='%s'\n", l2->ifname);
116		return -1;
117	}
118	if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
119	    pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
120		fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n",
121			pcap_geterr(l2->pcap));
122		return -1;
123	}
124	os_snprintf(pcap_filter, sizeof(pcap_filter),
125		    "not ether src " MACSTR " and "
126		    "( ether dst " MACSTR " or ether dst " MACSTR " ) and "
127		    "ether proto 0x%x",
128		    MAC2STR(l2->own_addr), /* do not receive own packets */
129		    MAC2STR(l2->own_addr), MAC2STR(pae_group_addr),
130		    protocol);
131	if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
132		fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
133		return -1;
134	}
135
136	if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
137		fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
138		return -1;
139	}
140
141	pcap_freecode(&pcap_fp);
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
157	eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
158				 l2_packet_receive, l2, l2->pcap);
159
160	return 0;
161}
162
163
164static int eth_get(const char *device, u8 ea[ETH_ALEN])
165{
166	struct if_msghdr *ifm;
167	struct sockaddr_dl *sdl;
168	u_char *p, *buf;
169	size_t len;
170	int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
171
172	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
173		return -1;
174	if ((buf = os_malloc(len)) == NULL)
175		return -1;
176	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
177		os_free(buf);
178		return -1;
179	}
180	for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
181		ifm = (struct if_msghdr *)p;
182		sdl = (struct sockaddr_dl *)(ifm + 1);
183		if (ifm->ifm_type != RTM_IFINFO ||
184		    (ifm->ifm_addrs & RTA_IFP) == 0)
185			continue;
186		if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
187		    os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
188			continue;
189		os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
190		break;
191	}
192	os_free(buf);
193
194	if (p >= buf + len) {
195		errno = ESRCH;
196		return -1;
197	}
198	return 0;
199}
200
201
202struct l2_packet_data * l2_packet_init(
203	const char *ifname, const u8 *own_addr, unsigned short protocol,
204	void (*rx_callback)(void *ctx, const u8 *src_addr,
205			    const u8 *buf, size_t len),
206	void *rx_callback_ctx, int l2_hdr)
207{
208	struct l2_packet_data *l2;
209
210	l2 = os_zalloc(sizeof(struct l2_packet_data));
211	if (l2 == NULL)
212		return NULL;
213	os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
214	l2->rx_callback = rx_callback;
215	l2->rx_callback_ctx = rx_callback_ctx;
216	l2->l2_hdr = l2_hdr;
217
218	if (eth_get(l2->ifname, l2->own_addr) < 0) {
219		fprintf(stderr, "Failed to get link-level address for "
220			"interface '%s'.\n", l2->ifname);
221		os_free(l2);
222		return NULL;
223	}
224
225	if (l2_packet_init_libpcap(l2, protocol)) {
226		os_free(l2);
227		return NULL;
228	}
229
230	return l2;
231}
232
233
234void l2_packet_deinit(struct l2_packet_data *l2)
235{
236	if (l2 != NULL) {
237		if (l2->pcap) {
238			eloop_unregister_read_sock(
239				pcap_get_selectable_fd(l2->pcap));
240			pcap_close(l2->pcap);
241		}
242		os_free(l2);
243	}
244}
245
246
247int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
248{
249	pcap_if_t *devs, *dev;
250	struct pcap_addr *addr;
251	struct sockaddr_in *saddr;
252	int found = 0;
253	char err[PCAP_ERRBUF_SIZE + 1];
254
255	if (pcap_findalldevs(&devs, err) < 0) {
256		wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
257		return -1;
258	}
259
260	for (dev = devs; dev && !found; dev = dev->next) {
261		if (os_strcmp(dev->name, l2->ifname) != 0)
262			continue;
263
264		addr = dev->addresses;
265		while (addr) {
266			saddr = (struct sockaddr_in *) addr->addr;
267			if (saddr && saddr->sin_family == AF_INET) {
268				os_strlcpy(buf, inet_ntoa(saddr->sin_addr),
269					   len);
270				found = 1;
271				break;
272			}
273			addr = addr->next;
274		}
275	}
276
277	pcap_freealldevs(devs);
278
279	return found ? 0 : -1;
280}
281
282
283void l2_packet_notify_auth_start(struct l2_packet_data *l2)
284{
285}
286