libeap/src/ap/ndisc_snoop.c

   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
  21 struct ip6addr {
  22         struct in6_addr addr;
  23         struct dl_list list;
  24 };
  25
  26 struct 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
  40 static 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
  56 void 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
  68 static 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
  84 static 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
  96 static 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
 166 int 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
 181 void ndisc_snoop_deinit(struct hostapd_data *hapd)
 182 {
 183         l2_packet_deinit(hapd->sock_ndisc);
 184 }