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
22 struct ip6addr {
23 struct in6_addr addr;
24 struct dl_list list;
25 };
26
27 struct 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
sta_ip6addr_add(struct sta_info * sta,struct in6_addr * addr)41 static 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
sta_ip6addr_del(struct hostapd_data * hapd,struct sta_info * sta)57 void 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 dl_list_del(&ip6addr->list);
65 os_free(ip6addr);
66 }
67 }
68
69
sta_has_ip6addr(struct sta_info * sta,struct in6_addr * addr)70 static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)
71 {
72 struct ip6addr *ip6addr;
73
74 dl_list_for_each(ip6addr, &sta->ip6addr, struct ip6addr, list) {
75 if (ip6addr->addr.s6_addr32[0] == addr->s6_addr32[0] &&
76 ip6addr->addr.s6_addr32[1] == addr->s6_addr32[1] &&
77 ip6addr->addr.s6_addr32[2] == addr->s6_addr32[2] &&
78 ip6addr->addr.s6_addr32[3] == addr->s6_addr32[3])
79 return 1;
80 }
81
82 return 0;
83 }
84
85
ucast_to_stas(struct hostapd_data * hapd,const u8 * buf,size_t len)86 static void ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)
87 {
88 struct sta_info *sta;
89
90 for (sta = hapd->sta_list; sta; sta = sta->next) {
91 if (!(sta->flags & WLAN_STA_AUTHORIZED))
92 continue;
93 x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);
94 }
95 }
96
97
handle_ndisc(void * ctx,const u8 * src_addr,const u8 * buf,size_t len)98 static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
99 size_t len)
100 {
101 struct hostapd_data *hapd = ctx;
102 struct icmpv6_ndmsg *msg;
103 struct in6_addr saddr;
104 struct sta_info *sta;
105 int res;
106 char addrtxt[INET6_ADDRSTRLEN + 1];
107
108 if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
109 return;
110 msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];
111 switch (msg->icmp6h.icmp6_type) {
112 case NEIGHBOR_SOLICITATION:
113 if (len < ETH_HLEN + sizeof(*msg))
114 return;
115 if (msg->opt_type != SOURCE_LL_ADDR)
116 return;
117
118 /*
119 * IPv6 header may not be 32-bit aligned in the buffer, so use
120 * a local copy to avoid unaligned reads.
121 */
122 os_memcpy(&saddr, &msg->ipv6h.ip6_src, sizeof(saddr));
123 if (!(saddr.s6_addr32[0] == 0 && saddr.s6_addr32[1] == 0 &&
124 saddr.s6_addr32[2] == 0 && saddr.s6_addr32[3] == 0)) {
125 if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)
126 return;
127 sta = ap_get_sta(hapd, msg->opt_lladdr);
128 if (!sta)
129 return;
130
131 if (sta_has_ip6addr(sta, &saddr))
132 return;
133
134 if (inet_ntop(AF_INET6, &saddr, addrtxt,
135 sizeof(addrtxt)) == NULL)
136 addrtxt[0] = '\0';
137 wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "
138 MACSTR, addrtxt, MAC2STR(sta->addr));
139 hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &saddr);
140 res = hostapd_drv_br_add_ip_neigh(hapd, 6,
141 (u8 *) &saddr,
142 128, sta->addr);
143 if (res) {
144 wpa_printf(MSG_ERROR,
145 "ndisc_snoop: Adding ip neigh failed: %d",
146 res);
147 return;
148 }
149
150 if (sta_ip6addr_add(sta, &saddr))
151 return;
152 }
153 break;
154 #ifdef CONFIG_HS20
155 case ROUTER_ADVERTISEMENT:
156 if (hapd->conf->disable_dgaf)
157 ucast_to_stas(hapd, buf, len);
158 break;
159 #endif /* CONFIG_HS20 */
160 case NEIGHBOR_ADVERTISEMENT:
161 if (hapd->conf->na_mcast_to_ucast)
162 ucast_to_stas(hapd, buf, len);
163 break;
164 default:
165 break;
166 }
167 }
168
169
ndisc_snoop_init(struct hostapd_data * hapd)170 int ndisc_snoop_init(struct hostapd_data *hapd)
171 {
172 hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
173 L2_PACKET_FILTER_NDISC);
174 if (hapd->sock_ndisc == NULL) {
175 wpa_printf(MSG_DEBUG,
176 "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
177 strerror(errno));
178 return -1;
179 }
180
181 return 0;
182 }
183
184
ndisc_snoop_deinit(struct hostapd_data * hapd)185 void ndisc_snoop_deinit(struct hostapd_data *hapd)
186 {
187 l2_packet_deinit(hapd->sock_ndisc);
188 hapd->sock_ndisc = NULL;
189 }
190