ndisc_snoop.c revision 281806 
1/*
2 * Neighbor Discovery snooping for Proxy ARP
3 * Copyright (c) 2014, Qualcomm Atheros, Inc.
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#include "utils/includes.h"
10#include <netinet/ip6.h>
11#include <netinet/icmp6.h>
12
13#include "utils/common.h"
14#include "l2_packet/l2_packet.h"
15#include "hostapd.h"
16#include "sta_info.h"
17#include "ap_drv_ops.h"
18#include "list.h"
19#include "x_snoop.h"
20
21struct ip6addr {
22	struct in6_addr addr;
23	struct dl_list list;
24};
25
26struct icmpv6_ndmsg {
27	struct ip6_hdr ipv6h;
28	struct icmp6_hdr icmp6h;
29	struct in6_addr target_addr;
30	u8 opt_type;
31	u8 len;
32	u8 opt_lladdr[0];
33} STRUCT_PACKED;
34
35#define ROUTER_ADVERTISEMENT	134
36#define NEIGHBOR_SOLICITATION	135
37#define NEIGHBOR_ADVERTISEMENT	136
38#define SOURCE_LL_ADDR		1
39
40static int sta_ip6addr_add(struct sta_info *sta, struct in6_addr *addr)
41{
42	struct ip6addr *ip6addr;
43
44	ip6addr = os_zalloc(sizeof(*ip6addr));
45	if (!ip6addr)
46		return -1;
47
48	os_memcpy(&ip6addr->addr, addr, sizeof(*addr));
49
50	dl_list_add_tail(&sta->ip6addr, &ip6addr->list);
51
52	return 0;
53}
54
55
56void sta_ip6addr_del(struct hostapd_data *hapd, struct sta_info *sta)
57{
58	struct ip6addr *ip6addr, *prev;
59
60	dl_list_for_each_safe(ip6addr, prev, &sta->ip6addr, struct ip6addr,
61			      list) {
62		hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &ip6addr->addr);
63		os_free(ip6addr);
64	}
65}
66
67
68static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)
69{
70	struct ip6addr *ip6addr;
71
72	dl_list_for_each(ip6addr, &sta->ip6addr, struct ip6addr, list) {
73		if (ip6addr->addr.s6_addr32[0] == addr->s6_addr32[0] &&
74		    ip6addr->addr.s6_addr32[1] == addr->s6_addr32[1] &&
75		    ip6addr->addr.s6_addr32[2] == addr->s6_addr32[2] &&
76		    ip6addr->addr.s6_addr32[3] == addr->s6_addr32[3])
77			return 1;
78	}
79
80	return 0;
81}
82
83
84static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
85			 size_t len)
86{
87	struct hostapd_data *hapd = ctx;
88	struct icmpv6_ndmsg *msg;
89	struct in6_addr *saddr;
90	struct sta_info *sta;
91	int res;
92	char addrtxt[INET6_ADDRSTRLEN + 1];
93
94	if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
95		return;
96	msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];
97	switch (msg->icmp6h.icmp6_type) {
98	case NEIGHBOR_SOLICITATION:
99		if (len < ETH_HLEN + sizeof(*msg))
100			return;
101		if (msg->opt_type != SOURCE_LL_ADDR)
102			return;
103
104		saddr = &msg->ipv6h.ip6_src;
105		if (!(saddr->s6_addr32[0] == 0 && saddr->s6_addr32[1] == 0 &&
106		      saddr->s6_addr32[2] == 0 && saddr->s6_addr32[3] == 0)) {
107			if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)
108				return;
109			sta = ap_get_sta(hapd, msg->opt_lladdr);
110			if (!sta)
111				return;
112
113			if (sta_has_ip6addr(sta, saddr))
114				return;
115
116			if (inet_ntop(AF_INET6, saddr, addrtxt, sizeof(addrtxt))
117			    == NULL)
118				addrtxt[0] = '\0';
119			wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "
120				   MACSTR, addrtxt, MAC2STR(sta->addr));
121			hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) saddr);
122			res = hostapd_drv_br_add_ip_neigh(hapd, 6, (u8 *) saddr,
123							  128, sta->addr);
124			if (res) {
125				wpa_printf(MSG_ERROR,
126					   "ndisc_snoop: Adding ip neigh failed: %d",
127					   res);
128				return;
129			}
130
131			if (sta_ip6addr_add(sta, saddr))
132				return;
133		}
134		break;
135	case ROUTER_ADVERTISEMENT:
136		if (!hapd->conf->disable_dgaf)
137			return;
138		/* fall through */
139	case NEIGHBOR_ADVERTISEMENT:
140		for (sta = hapd->sta_list; sta; sta = sta->next) {
141			if (!(sta->flags & WLAN_STA_AUTHORIZED))
142				continue;
143			x_snoop_mcast_to_ucast_convert_send(hapd, sta,
144							    (u8 *) buf, len);
145		}
146		break;
147	default:
148		break;
149	}
150}
151
152
153int ndisc_snoop_init(struct hostapd_data *hapd)
154{
155	hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
156						 L2_PACKET_FILTER_NDISC);
157	if (hapd->sock_ndisc == NULL) {
158		wpa_printf(MSG_DEBUG,
159			   "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
160			   strerror(errno));
161		return -1;
162	}
163
164	return 0;
165}
166
167
168void ndisc_snoop_deinit(struct hostapd_data *hapd)
169{
170	l2_packet_deinit(hapd->sock_ndisc);
171}
172