aboutsummaryrefslogtreecommitdiffstats
path: root/src/l2_packet/l2_packet_linux.c
blob: fcbf7e040fe92f936c9e566f6908fbcb19b3d90c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
/*
 * WPA Supplicant - Layer2 packet handling with Linux packet sockets
 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"
#include <sys/ioctl.h>
#include <netpacket/packet.h>
#include <net/if.h>
#include <linux/filter.h>

#include "common.h"
#include "eloop.h"
#include "l2_packet.h"


struct l2_packet_data {
	int fd; /* packet socket for EAPOL frames */
	char ifname[IFNAMSIZ + 1];
	int ifindex;
	u8 own_addr[ETH_ALEN];
	void (*rx_callback)(void *ctx, const u8 *src_addr,
			    const u8 *buf, size_t len);
	void *rx_callback_ctx;
	int l2_hdr; /* whether to include layer 2 (Ethernet) header data
		     * buffers */
};

/* Generated by 'sudo tcpdump -s 3000 -dd greater 278 and ip and udp and
 * src port bootps and dst port bootpc'
 */
static struct sock_filter dhcp_sock_filter_insns[] = {
	{ 0x80, 0, 0, 0x00000000 },
	{ 0x35, 0, 12, 0x00000116 },
	{ 0x28, 0, 0, 0x0000000c },
	{ 0x15, 0, 10, 0x00000800 },
	{ 0x30, 0, 0, 0x00000017 },
	{ 0x15, 0, 8, 0x00000011 },
	{ 0x28, 0, 0, 0x00000014 },
	{ 0x45, 6, 0, 0x00001fff },
	{ 0xb1, 0, 0, 0x0000000e },
	{ 0x48, 0, 0, 0x0000000e },
	{ 0x15, 0, 3, 0x00000043 },
	{ 0x48, 0, 0, 0x00000010 },
	{ 0x15, 0, 1, 0x00000044 },
	{ 0x6, 0, 0, 0x00000bb8 },
	{ 0x6, 0, 0, 0x00000000 },
};

static const struct sock_fprog dhcp_sock_filter = {
	.len = ARRAY_SIZE(dhcp_sock_filter_insns),
	.filter = dhcp_sock_filter_insns,
};


int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
	os_memcpy(addr, l2->own_addr, ETH_ALEN);
	return 0;
}


int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
		   const u8 *buf, size_t len)
{
	int ret;
	if (l2 == NULL)
		return -1;
	if (l2->l2_hdr) {
		ret = send(l2->fd, buf, len, 0);
		if (ret < 0)
			wpa_printf(MSG_ERROR, "l2_packet_send - send: %s",
				   strerror(errno));
	} else {
		struct sockaddr_ll ll;
		os_memset(&ll, 0, sizeof(ll));
		ll.sll_family = AF_PACKET;
		ll.sll_ifindex = l2->ifindex;
		ll.sll_protocol = htons(proto);
		ll.sll_halen = ETH_ALEN;
		os_memcpy(ll.sll_addr, dst_addr, ETH_ALEN);
		ret = sendto(l2->fd, buf, len, 0, (struct sockaddr *) &ll,
			     sizeof(ll));
		if (ret < 0) {
			wpa_printf(MSG_ERROR, "l2_packet_send - sendto: %s",
				   strerror(errno));
		}
	}
	return ret;
}


static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
	struct l2_packet_data *l2 = eloop_ctx;
	u8 buf[2300];
	int res;
	struct sockaddr_ll ll;
	socklen_t fromlen;

	os_memset(&ll, 0, sizeof(ll));
	fromlen = sizeof(ll);
	res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll,
		       &fromlen);
	if (res < 0) {
		wpa_printf(MSG_DEBUG, "l2_packet_receive - recvfrom: %s",
			   strerror(errno));
		return;
	}

	l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}


struct l2_packet_data * l2_packet_init(
	const char *ifname, const u8 *own_addr, unsigned short protocol,
	void (*rx_callback)(void *ctx, const u8 *src_addr,
			    const u8 *buf, size_t len),
	void *rx_callback_ctx, int l2_hdr)
{
	struct l2_packet_data *l2;
	struct ifreq ifr;
	struct sockaddr_ll ll;

	l2 = os_zalloc(sizeof(struct l2_packet_data));
	if (l2 == NULL)
		return NULL;
	os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
	l2->rx_callback = rx_callback;
	l2->rx_callback_ctx = rx_callback_ctx;
	l2->l2_hdr = l2_hdr;

	l2->fd = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM,
			htons(protocol));
	if (l2->fd < 0) {
		wpa_printf(MSG_ERROR, "%s: socket(PF_PACKET): %s",
			   __func__, strerror(errno));
		os_free(l2);
		return NULL;
	}
	os_memset(&ifr, 0, sizeof(ifr));
	os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
	if (ioctl(l2->fd, SIOCGIFINDEX, &ifr) < 0) {
		wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFINDEX]: %s",
			   __func__, strerror(errno));
		close(l2->fd);
		os_free(l2);
		return NULL;
	}
	l2->ifindex = ifr.ifr_ifindex;

	os_memset(&ll, 0, sizeof(ll));
	ll.sll_family = PF_PACKET;
	ll.sll_ifindex = ifr.ifr_ifindex;
	ll.sll_protocol = htons(protocol);
	if (bind(l2->fd, (struct sockaddr *) &ll, sizeof(ll)) < 0) {
		wpa_printf(MSG_ERROR, "%s: bind[PF_PACKET]: %s",
			   __func__, strerror(errno));
		close(l2->fd);
		os_free(l2);
		return NULL;
	}

	if (ioctl(l2->fd, SIOCGIFHWADDR, &ifr) < 0) {
		wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFHWADDR]: %s",
			   __func__, strerror(errno));
		close(l2->fd);
		os_free(l2);
		return NULL;
	}
	os_memcpy(l2->own_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);

	eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL);

	return l2;
}


void l2_packet_deinit(struct l2_packet_data *l2)
{
	if (l2 == NULL)
		return;

	if (l2->fd >= 0) {
		eloop_unregister_read_sock(l2->fd);
		close(l2->fd);
	}
		
	os_free(l2);
}


int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
{
	int s;
	struct ifreq ifr;
	struct sockaddr_in *saddr;
	size_t res;

	s = socket(PF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
		wpa_printf(MSG_ERROR, "%s: socket: %s",
			   __func__, strerror(errno));
		return -1;
	}
	os_memset(&ifr, 0, sizeof(ifr));
	os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
	if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
		if (errno != EADDRNOTAVAIL)
			wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFADDR]: %s",
				   __func__, strerror(errno));
		close(s);
		return -1;
	}
	close(s);
	saddr = aliasing_hide_typecast(&ifr.ifr_addr, struct sockaddr_in);
	if (saddr->sin_family != AF_INET)
		return -1;
	res = os_strlcpy(buf, inet_ntoa(saddr->sin_addr), len);
	if (res >= len)
		return -1;
	return 0;
}


void l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
}


int l2_packet_set_packet_filter(struct l2_packet_data *l2,
				enum l2_packet_filter_type type)
{
	const struct sock_fprog *sock_filter;

	switch (type) {
	case L2_PACKET_FILTER_DHCP:
		sock_filter = &dhcp_sock_filter;
		break;
	default:
		return -1;
	}

	if (setsockopt(l2->fd, SOL_SOCKET, SO_ATTACH_FILTER,
		       sock_filter, sizeof(struct sock_fprog))) {
		wpa_printf(MSG_ERROR,
			   "l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s",
			   strerror(errno));
		return -1;
	}

	return 0;
}