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 os_free(ip6addr);
65 }
66 }
67
68
sta_has_ip6addr(struct sta_info * sta,struct in6_addr * addr)69 static 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
ucast_to_stas(struct hostapd_data * hapd,const u8 * buf,size_t len)85 static 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
handle_ndisc(void * ctx,const u8 * src_addr,const u8 * buf,size_t len)97 static 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 #ifdef CONFIG_HS20
154 case ROUTER_ADVERTISEMENT:
155 if (hapd->conf->disable_dgaf)
156 ucast_to_stas(hapd, buf, len);
157 break;
158 #endif /* CONFIG_HS20 */
159 case NEIGHBOR_ADVERTISEMENT:
160 if (hapd->conf->na_mcast_to_ucast)
161 ucast_to_stas(hapd, buf, len);
162 break;
163 default:
164 break;
165 }
166 }
167
168
ndisc_snoop_init(struct hostapd_data * hapd)169 int ndisc_snoop_init(struct hostapd_data *hapd)
170 {
171 hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,
172 L2_PACKET_FILTER_NDISC);
173 if (hapd->sock_ndisc == NULL) {
174 wpa_printf(MSG_DEBUG,
175 "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",
176 strerror(errno));
177 return -1;
178 }
179
180 return 0;
181 }
182
183
ndisc_snoop_deinit(struct hostapd_data * hapd)184 void ndisc_snoop_deinit(struct hostapd_data *hapd)
185 {
186 l2_packet_deinit(hapd->sock_ndisc);
187 hapd->sock_ndisc = NULL;
188 }
189
