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#include "ndisc_snoop.h"
21
22struct ip6addr {
23	struct in6_addr addr;
24	struct dl_list list;
25};
26
27struct icmpv6_ndmsg {
28	struct ip6_hdr ipv6h;
29	struct icmp6_hdr icmp6h;
30	struct in6_addr target_addr;
31	u8 opt_type;
32	u8 len;
33	u8 opt_lladdr[0];
34} STRUCT_PACKED;
35
36#define ROUTER_ADVERTISEMENT	134
37#define NEIGHBOR_SOLICITATION	135
38#define NEIGHBOR_ADVERTISEMENT	136
39#define SOURCE_LL_ADDR		1
40
41static int sta_ip6addr_add(struct sta_info *sta, struct in6_addr *addr)
42{
43	struct ip6addr *ip6addr;
44
45	ip6addr = os_zalloc(sizeof(*ip6addr));
46	if (!ip6addr)
47		return -1;
48
49	os_memcpy(&ip6addr->addr, addr, sizeof(*addr));
50
51	dl_list_add_tail(&sta->ip6addr, &ip6addr->list);
52
53	return 0;
54}
55
56
57void sta_ip6addr_del(struct hostapd_data *hapd, struct sta_info *sta)
58{
59	struct ip6addr *ip6addr, *prev;
60
61	dl_list_for_each_safe(ip6addr, prev, &sta->ip6addr, struct ip6addr,
62			      list) {
63		hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &ip6addr->addr);
64		os_free(ip6addr);
65	}
66}
67
68
69static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)
70{
71	struct ip6addr *ip6addr;
72
73	dl_list_for_each(ip6addr, &sta->ip6addr, struct ip6addr, list) {
74		if (ip6addr->addr.s6_addr32[0] == addr->s6_addr32[0] &&
75		    ip6addr->addr.s6_addr32[1] == addr->s6_addr32[1] &&
76		    ip6addr->addr.s6_addr32[2] == addr->s6_addr32[2] &&
77		    ip6addr->addr.s6_addr32[3] == addr->s6_addr32[3])
78			return 1;
79	}
80
81	return 0;
82}
83
84
85static void ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)
86{
87	struct sta_info *sta;
88
89	for (sta = hapd->sta_list; sta; sta = sta->next) {
90		if (!(sta->flags & WLAN_STA_AUTHORIZED))
91			continue;
92		x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);
93	}
94}
95
96
97static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
98			 size_t len)
99{
100	struct hostapd_data *hapd = ctx;
101	struct icmpv6_ndmsg *msg;
102	struct in6_addr saddr;
103	struct sta_info *sta;
104	int res;
105	char addrtxt[INET6_ADDRSTRLEN + 1];
106
107	if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
108		return;
109	msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];
110	switch (msg->icmp6h.icmp6_type) {
111	case NEIGHBOR_SOLICITATION:
112		if (len < ETH_HLEN + sizeof(*msg))
113			return;
114		if (msg->opt_type != SOURCE_LL_ADDR)
115			return;
116
117		/*
118		 * IPv6 header may not be 32-bit aligned in the buffer, so use
119		 * a local copy to avoid unaligned reads.
120		 */
121		os_memcpy(&saddr, &msg->ipv6h.ip6_src, sizeof(saddr));
122		if (!(saddr.s6_addr32[0] == 0 && saddr.s6_addr32[1] == 0 &&
123		      saddr.s6_addr32[2] == 0 && saddr.s6_addr32[3] == 0)) {
124			if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)
125				return;
126			sta = ap_get_sta(hapd, msg->opt_lladdr);
127			if (!sta)
128				return;
129
130			if (sta_has_ip6addr(sta, &saddr))
131				return;
132
133			if (inet_ntop(AF_INET6, &saddr, addrtxt,
134				      sizeof(addrtxt)) == NULL)
135				addrtxt[0] = '\0';
136			wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "
137				   MACSTR, addrtxt, MAC2STR(sta->addr));
138			hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &saddr);
139			res = hostapd_drv_br_add_ip_neigh(hapd, 6,
140							  (u8 *) &saddr,
141							  128, sta->addr);
142			if (res) {
143				wpa_printf(MSG_ERROR,
144					   "ndisc_snoop: Adding ip neigh failed: %d",
145					   res);
146				return;
147			}
148
149			if (sta_ip6addr_add(sta, &saddr))
150				return;
151		}
152		break;
153	case ROUTER_ADVERTISEMENT:
154		if (hapd->conf->disable_dgaf)
155			ucast_to_stas(hapd, buf, len);
156		break;
157	case NEIGHBOR_ADVERTISEMENT:
158		if (hapd->conf->na_mcast_to_ucast)
159			ucast_to_stas(hapd, buf, len);
160		break;
161	default:
162		break;
163	}
164}
165
166
167int ndisc_snoop_init(struct hostapd_data *hapd)
168{
169	hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
170						 L2_PACKET_FILTER_NDISC);
171	if (hapd->sock_ndisc == NULL) {
172		wpa_printf(MSG_DEBUG,
173			   "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
174			   strerror(errno));
175		return -1;
176	}
177
178	return 0;
179}
180
181
182void ndisc_snoop_deinit(struct hostapd_data *hapd)
183{
184	l2_packet_deinit(hapd->sock_ndisc);
185	hapd->sock_ndisc = NULL;
186}
187