ndisc_snoop.c revision 289549 
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 ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)
85{
86	struct sta_info *sta;
87
88	for (sta = hapd->sta_list; sta; sta = sta->next) {
89		if (!(sta->flags & WLAN_STA_AUTHORIZED))
90			continue;
91		x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);
92	}
93}
94
95
96static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
97			 size_t len)
98{
99	struct hostapd_data *hapd = ctx;
100	struct icmpv6_ndmsg *msg;
101	struct in6_addr saddr;
102	struct sta_info *sta;
103	int res;
104	char addrtxt[INET6_ADDRSTRLEN + 1];
105
106	if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
107		return;
108	msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];
109	switch (msg->icmp6h.icmp6_type) {
110	case NEIGHBOR_SOLICITATION:
111		if (len < ETH_HLEN + sizeof(*msg))
112			return;
113		if (msg->opt_type != SOURCE_LL_ADDR)
114			return;
115
116		/*
117		 * IPv6 header may not be 32-bit aligned in the buffer, so use
118		 * a local copy to avoid unaligned reads.
119		 */
120		os_memcpy(&saddr, &msg->ipv6h.ip6_src, sizeof(saddr));
121		if (!(saddr.s6_addr32[0] == 0 && saddr.s6_addr32[1] == 0 &&
122		      saddr.s6_addr32[2] == 0 && saddr.s6_addr32[3] == 0)) {
123			if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)
124				return;
125			sta = ap_get_sta(hapd, msg->opt_lladdr);
126			if (!sta)
127				return;
128
129			if (sta_has_ip6addr(sta, &saddr))
130				return;
131
132			if (inet_ntop(AF_INET6, &saddr, addrtxt,
133				      sizeof(addrtxt)) == NULL)
134				addrtxt[0] = '\0';
135			wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "
136				   MACSTR, addrtxt, MAC2STR(sta->addr));
137			hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &saddr);
138			res = hostapd_drv_br_add_ip_neigh(hapd, 6,
139							  (u8 *) &saddr,
140							  128, sta->addr);
141			if (res) {
142				wpa_printf(MSG_ERROR,
143					   "ndisc_snoop: Adding ip neigh failed: %d",
144					   res);
145				return;
146			}
147
148			if (sta_ip6addr_add(sta, &saddr))
149				return;
150		}
151		break;
152	case ROUTER_ADVERTISEMENT:
153		if (hapd->conf->disable_dgaf)
154			ucast_to_stas(hapd, buf, len);
155		break;
156	case NEIGHBOR_ADVERTISEMENT:
157		if (hapd->conf->na_mcast_to_ucast)
158			ucast_to_stas(hapd, buf, len);
159		break;
160	default:
161		break;
162	}
163}
164
165
166int ndisc_snoop_init(struct hostapd_data *hapd)
167{
168	hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
169						 L2_PACKET_FILTER_NDISC);
170	if (hapd->sock_ndisc == NULL) {
171		wpa_printf(MSG_DEBUG,
172			   "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
173			   strerror(errno));
174		return -1;
175	}
176
177	return 0;
178}
179
180
181void ndisc_snoop_deinit(struct hostapd_data *hapd)
182{
183	l2_packet_deinit(hapd->sock_ndisc);
184}
185