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
23static const u8 pae_group_addr[ETH_ALEN] =
24{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 };
25
26struct 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
43int 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
51static 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
78int 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
118static 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 (packet == NULL || 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
147static 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 (pkt_data == NULL || 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
175static 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
197static 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
279struct 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
315struct 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
327void 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
345int 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
381void 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
396int l2_packet_set_packet_filter(struct l2_packet_data *l2,
397				enum l2_packet_filter_type type)
398{
399	return -1;
400}
401