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