iapp.c
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00001 /*
00002  * hostapd / IEEE 802.11F-2003 Inter-Access Point Protocol (IAPP)
00003  * Copyright (c) 2002-2007, Jouni Malinen <j@w1.fi>
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License version 2 as
00007  * published by the Free Software Foundation.
00008  *
00009  * Alternatively, this software may be distributed under the terms of BSD
00010  * license.
00011  *
00012  * See README and COPYING for more details.
00013  *
00014  * Note: IEEE 802.11F-2003 was a experimental use specification. It has expired
00015  * and IEEE has withdrawn it. In other words, it is likely better to look at
00016  * using some other mechanism for AP-to-AP communication than extending the
00017  * implementation here.
00018  */
00019 
00020 /* TODO:
00021  * Level 1: no administrative or security support
00022  *      (e.g., static BSSID to IP address mapping in each AP)
00023  * Level 2: support for dynamic mapping of BSSID to IP address
00024  * Level 3: support for encryption and authentication of IAPP messages
00025  * - add support for MOVE-notify and MOVE-response (this requires support for
00026  *   finding out IP address for previous AP using RADIUS)
00027  * - add support for Send- and ACK-Security-Block to speedup IEEE 802.1X during
00028  *   reassociation to another AP
00029  * - implement counters etc. for IAPP MIB
00030  * - verify endianness of fields in IAPP messages; are they big-endian as
00031  *   used here?
00032  * - RADIUS connection for AP registration and BSSID to IP address mapping
00033  * - TCP connection for IAPP MOVE, CACHE
00034  * - broadcast ESP for IAPP ADD-notify
00035  * - ESP for IAPP MOVE messages
00036  * - security block sending/processing
00037  * - IEEE 802.11 context transfer
00038  */
00039 
00040 #include "utils/includes.h"
00041 #include <net/if.h>
00042 #include <sys/ioctl.h>
00043 #ifdef USE_KERNEL_HEADERS
00044 #include <linux/if_packet.h>
00045 #else /* USE_KERNEL_HEADERS */
00046 #include <netpacket/packet.h>
00047 #endif /* USE_KERNEL_HEADERS */
00048 
00049 #include "utils/common.h"
00050 #include "utils/eloop.h"
00051 #include "common/ieee802_11_defs.h"
00052 #include "hostapd.h"
00053 #include "ap_config.h"
00054 #include "ieee802_11.h"
00055 #include "sta_info.h"
00056 #include "iapp.h"
00057 
00058 
00059 #define IAPP_MULTICAST "224.0.1.178"
00060 #define IAPP_UDP_PORT 3517
00061 #define IAPP_TCP_PORT 3517
00062 
00063 struct iapp_hdr {
00064         u8 version;
00065         u8 command;
00066         be16 identifier;
00067         be16 length;
00068         /* followed by length-6 octets of data */
00069 } __attribute__ ((packed));
00070 
00071 #define IAPP_VERSION 0
00072 
00073 enum IAPP_COMMAND {
00074         IAPP_CMD_ADD_notify = 0,
00075         IAPP_CMD_MOVE_notify = 1,
00076         IAPP_CMD_MOVE_response = 2,
00077         IAPP_CMD_Send_Security_Block = 3,
00078         IAPP_CMD_ACK_Security_Block = 4,
00079         IAPP_CMD_CACHE_notify = 5,
00080         IAPP_CMD_CACHE_response = 6,
00081 };
00082 
00083 
00084 /* ADD-notify - multicast UDP on the local LAN */
00085 struct iapp_add_notify {
00086         u8 addr_len; /* ETH_ALEN */
00087         u8 reserved;
00088         u8 mac_addr[ETH_ALEN];
00089         be16 seq_num;
00090 } __attribute__ ((packed));
00091 
00092 
00093 /* Layer 2 Update frame (802.2 Type 1 LLC XID Update response) */
00094 struct iapp_layer2_update {
00095         u8 da[ETH_ALEN]; /* broadcast */
00096         u8 sa[ETH_ALEN]; /* STA addr */
00097         be16 len; /* 6 */
00098         u8 dsap; /* null DSAP address */
00099         u8 ssap; /* null SSAP address, CR=Response */
00100         u8 control;
00101         u8 xid_info[3];
00102 } __attribute__ ((packed));
00103 
00104 
00105 /* MOVE-notify - unicast TCP */
00106 struct iapp_move_notify {
00107         u8 addr_len; /* ETH_ALEN */
00108         u8 reserved;
00109         u8 mac_addr[ETH_ALEN];
00110         u16 seq_num;
00111         u16 ctx_block_len;
00112         /* followed by ctx_block_len bytes */
00113 } __attribute__ ((packed));
00114 
00115 
00116 /* MOVE-response - unicast TCP */
00117 struct iapp_move_response {
00118         u8 addr_len; /* ETH_ALEN */
00119         u8 status;
00120         u8 mac_addr[ETH_ALEN];
00121         u16 seq_num;
00122         u16 ctx_block_len;
00123         /* followed by ctx_block_len bytes */
00124 } __attribute__ ((packed));
00125 
00126 enum {
00127         IAPP_MOVE_SUCCESSFUL = 0,
00128         IAPP_MOVE_DENIED = 1,
00129         IAPP_MOVE_STALE_MOVE = 2,
00130 };
00131 
00132 
00133 /* CACHE-notify */
00134 struct iapp_cache_notify {
00135         u8 addr_len; /* ETH_ALEN */
00136         u8 reserved;
00137         u8 mac_addr[ETH_ALEN];
00138         u16 seq_num;
00139         u8 current_ap[ETH_ALEN];
00140         u16 ctx_block_len;
00141         /* ctx_block_len bytes of context block followed by 16-bit context
00142          * timeout */
00143 } __attribute__ ((packed));
00144 
00145 
00146 /* CACHE-response - unicast TCP */
00147 struct iapp_cache_response {
00148         u8 addr_len; /* ETH_ALEN */
00149         u8 status;
00150         u8 mac_addr[ETH_ALEN];
00151         u16 seq_num;
00152 } __attribute__ ((packed));
00153 
00154 enum {
00155         IAPP_CACHE_SUCCESSFUL = 0,
00156         IAPP_CACHE_STALE_CACHE = 1,
00157 };
00158 
00159 
00160 /* Send-Security-Block - unicast TCP */
00161 struct iapp_send_security_block {
00162         u8 iv[8];
00163         u16 sec_block_len;
00164         /* followed by sec_block_len bytes of security block */
00165 } __attribute__ ((packed));
00166 
00167 
00168 /* ACK-Security-Block - unicast TCP */
00169 struct iapp_ack_security_block {
00170         u8 iv[8];
00171         u8 new_ap_ack_authenticator[48];
00172 } __attribute__ ((packed));
00173 
00174 
00175 struct iapp_data {
00176         struct hostapd_data *hapd;
00177         u16 identifier; /* next IAPP identifier */
00178         struct in_addr own, multicast;
00179         int udp_sock;
00180         int packet_sock;
00181 };
00182 
00183 
00184 static void iapp_send_add(struct iapp_data *iapp, u8 *mac_addr, u16 seq_num)
00185 {
00186         char buf[128];
00187         struct iapp_hdr *hdr;
00188         struct iapp_add_notify *add;
00189         struct sockaddr_in addr;
00190 
00191         /* Send IAPP ADD-notify to remove possible association from other APs
00192          */
00193 
00194         hdr = (struct iapp_hdr *) buf;
00195         hdr->version = IAPP_VERSION;
00196         hdr->command = IAPP_CMD_ADD_notify;
00197         hdr->identifier = host_to_be16(iapp->identifier++);
00198         hdr->length = host_to_be16(sizeof(*hdr) + sizeof(*add));
00199 
00200         add = (struct iapp_add_notify *) (hdr + 1);
00201         add->addr_len = ETH_ALEN;
00202         add->reserved = 0;
00203         os_memcpy(add->mac_addr, mac_addr, ETH_ALEN);
00204 
00205         add->seq_num = host_to_be16(seq_num);
00206         
00207         os_memset(&addr, 0, sizeof(addr));
00208         addr.sin_family = AF_INET;
00209         addr.sin_addr.s_addr = iapp->multicast.s_addr;
00210         addr.sin_port = htons(IAPP_UDP_PORT);
00211         if (sendto(iapp->udp_sock, buf, (char *) (add + 1) - buf, 0,
00212                    (struct sockaddr *) &addr, sizeof(addr)) < 0)
00213                 perror("sendto[IAPP-ADD]");
00214 }
00215 
00216 
00217 static void iapp_send_layer2_update(struct iapp_data *iapp, u8 *addr)
00218 {
00219         struct iapp_layer2_update msg;
00220 
00221         /* Send Level 2 Update Frame to update forwarding tables in layer 2
00222          * bridge devices */
00223 
00224         /* 802.2 Type 1 Logical Link Control (LLC) Exchange Identifier (XID)
00225          * Update response frame; IEEE Std 802.2-1998, 5.4.1.2.1 */
00226 
00227         os_memset(msg.da, 0xff, ETH_ALEN);
00228         os_memcpy(msg.sa, addr, ETH_ALEN);
00229         msg.len = host_to_be16(6);
00230         msg.dsap = 0; /* NULL DSAP address */
00231         msg.ssap = 0x01; /* NULL SSAP address, CR Bit: Response */
00232         msg.control = 0xaf; /* XID response lsb.1111F101.
00233                              * F=0 (no poll command; unsolicited frame) */
00234         msg.xid_info[0] = 0x81; /* XID format identifier */
00235         msg.xid_info[1] = 1; /* LLC types/classes: Type 1 LLC */
00236         msg.xid_info[2] = 1 << 1; /* XID sender's receive window size (RW)
00237                                    * FIX: what is correct RW with 802.11? */
00238 
00239         if (send(iapp->packet_sock, &msg, sizeof(msg), 0) < 0)
00240                 perror("send[L2 Update]");
00241 }
00242 
00243 
00249 void iapp_new_station(struct iapp_data *iapp, struct sta_info *sta)
00250 {
00251         struct ieee80211_mgmt *assoc;
00252         u16 seq;
00253 
00254         if (iapp == NULL)
00255                 return;
00256 
00257         assoc = sta->last_assoc_req;
00258         seq = assoc ? WLAN_GET_SEQ_SEQ(le_to_host16(assoc->seq_ctrl)) : 0;
00259 
00260         /* IAPP-ADD.request(MAC Address, Sequence Number, Timeout) */
00261         hostapd_logger(iapp->hapd, sta->addr, HOSTAPD_MODULE_IAPP,
00262                        HOSTAPD_LEVEL_DEBUG, "IAPP-ADD.request(seq=%d)", seq);
00263         iapp_send_layer2_update(iapp, sta->addr);
00264         iapp_send_add(iapp, sta->addr, seq);
00265 
00266         if (assoc && WLAN_FC_GET_STYPE(le_to_host16(assoc->frame_control)) ==
00267             WLAN_FC_STYPE_REASSOC_REQ) {
00268                 /* IAPP-MOVE.request(MAC Address, Sequence Number, Old AP,
00269                  *                   Context Block, Timeout)
00270                  */
00271                 /* TODO: Send IAPP-MOVE to the old AP; Map Old AP BSSID to
00272                  * IP address */
00273         }
00274 }
00275 
00276 
00277 static void iapp_process_add_notify(struct iapp_data *iapp,
00278                                     struct sockaddr_in *from,
00279                                     struct iapp_hdr *hdr, int len)
00280 {
00281         struct iapp_add_notify *add = (struct iapp_add_notify *) (hdr + 1);
00282         struct sta_info *sta;
00283 
00284         if (len != sizeof(*add)) {
00285                 printf("Invalid IAPP-ADD packet length %d (expected %lu)\n",
00286                        len, (unsigned long) sizeof(*add));
00287                 return;
00288         }
00289 
00290         sta = ap_get_sta(iapp->hapd, add->mac_addr);
00291 
00292         /* IAPP-ADD.indication(MAC Address, Sequence Number) */
00293         hostapd_logger(iapp->hapd, add->mac_addr, HOSTAPD_MODULE_IAPP,
00294                        HOSTAPD_LEVEL_INFO,
00295                        "Received IAPP ADD-notify (seq# %d) from %s:%d%s",
00296                        be_to_host16(add->seq_num),
00297                        inet_ntoa(from->sin_addr), ntohs(from->sin_port),
00298                        sta ? "" : " (STA not found)");
00299 
00300         if (!sta)
00301                 return;
00302 
00303         /* TODO: could use seq_num to try to determine whether last association
00304          * to this AP is newer than the one advertised in IAPP-ADD. Although,
00305          * this is not really a reliable verification. */
00306 
00307         hostapd_logger(iapp->hapd, add->mac_addr, HOSTAPD_MODULE_IAPP,
00308                        HOSTAPD_LEVEL_DEBUG,
00309                        "Removing STA due to IAPP ADD-notify");
00310         ap_sta_disconnect(iapp->hapd, sta, NULL, 0);
00311 }
00312 
00313 
00320 static void iapp_receive_udp(int sock, void *eloop_ctx, void *sock_ctx)
00321 {
00322         struct iapp_data *iapp = eloop_ctx;
00323         int len, hlen;
00324         unsigned char buf[128];
00325         struct sockaddr_in from;
00326         socklen_t fromlen;
00327         struct iapp_hdr *hdr;
00328 
00329         /* Handle incoming IAPP frames (over UDP/IP) */
00330 
00331         fromlen = sizeof(from);
00332         len = recvfrom(iapp->udp_sock, buf, sizeof(buf), 0,
00333                        (struct sockaddr *) &from, &fromlen);
00334         if (len < 0) {
00335                 perror("recvfrom");
00336                 return;
00337         }
00338 
00339         if (from.sin_addr.s_addr == iapp->own.s_addr)
00340                 return; /* ignore own IAPP messages */
00341 
00342         hostapd_logger(iapp->hapd, NULL, HOSTAPD_MODULE_IAPP,
00343                        HOSTAPD_LEVEL_DEBUG,
00344                        "Received %d byte IAPP frame from %s%s\n",
00345                        len, inet_ntoa(from.sin_addr),
00346                        len < (int) sizeof(*hdr) ? " (too short)" : "");
00347 
00348         if (len < (int) sizeof(*hdr))
00349                 return;
00350 
00351         hdr = (struct iapp_hdr *) buf;
00352         hlen = be_to_host16(hdr->length);
00353         hostapd_logger(iapp->hapd, NULL, HOSTAPD_MODULE_IAPP,
00354                        HOSTAPD_LEVEL_DEBUG,
00355                        "RX: version=%d command=%d id=%d len=%d\n",
00356                        hdr->version, hdr->command,
00357                        be_to_host16(hdr->identifier), hlen);
00358         if (hdr->version != IAPP_VERSION) {
00359                 printf("Dropping IAPP frame with unknown version %d\n",
00360                        hdr->version);
00361                 return;
00362         }
00363         if (hlen > len) {
00364                 printf("Underflow IAPP frame (hlen=%d len=%d)\n", hlen, len);
00365                 return;
00366         }
00367         if (hlen < len) {
00368                 printf("Ignoring %d extra bytes from IAPP frame\n",
00369                        len - hlen);
00370                 len = hlen;
00371         }
00372 
00373         switch (hdr->command) {
00374         case IAPP_CMD_ADD_notify:
00375                 iapp_process_add_notify(iapp, &from, hdr, hlen - sizeof(*hdr));
00376                 break;
00377         case IAPP_CMD_MOVE_notify:
00378                 /* TODO: MOVE is using TCP; so move this to TCP handler once it
00379                  * is implemented.. */
00380                 /* IAPP-MOVE.indication(MAC Address, New BSSID,
00381                  * Sequence Number, AP Address, Context Block) */
00382                 /* TODO: process */
00383                 break;
00384         default:
00385                 printf("Unknown IAPP command %d\n", hdr->command);
00386                 break;
00387         }
00388 }
00389 
00390 
00391 struct iapp_data * iapp_init(struct hostapd_data *hapd, const char *iface)
00392 {
00393         struct ifreq ifr;
00394         struct sockaddr_ll addr;
00395         int ifindex;
00396         struct sockaddr_in *paddr, uaddr;
00397         struct iapp_data *iapp;
00398         struct ip_mreqn mreq;
00399 
00400         iapp = os_zalloc(sizeof(*iapp));
00401         if (iapp == NULL)
00402                 return NULL;
00403         iapp->hapd = hapd;
00404         iapp->udp_sock = iapp->packet_sock = -1;
00405 
00406         /* TODO:
00407          * open socket for sending and receiving IAPP frames over TCP
00408          */
00409 
00410         iapp->udp_sock = socket(PF_INET, SOCK_DGRAM, 0);
00411         if (iapp->udp_sock < 0) {
00412                 perror("socket[PF_INET,SOCK_DGRAM]");
00413                 iapp_deinit(iapp);
00414                 return NULL;
00415         }
00416 
00417         os_memset(&ifr, 0, sizeof(ifr));
00418         os_strlcpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));
00419         if (ioctl(iapp->udp_sock, SIOCGIFINDEX, &ifr) != 0) {
00420                 perror("ioctl(SIOCGIFINDEX)");
00421                 iapp_deinit(iapp);
00422                 return NULL;
00423         }
00424         ifindex = ifr.ifr_ifindex;
00425 
00426         if (ioctl(iapp->udp_sock, SIOCGIFADDR, &ifr) != 0) {
00427                 perror("ioctl(SIOCGIFADDR)");
00428                 iapp_deinit(iapp);
00429                 return NULL;
00430         }
00431         paddr = (struct sockaddr_in *) &ifr.ifr_addr;
00432         if (paddr->sin_family != AF_INET) {
00433                 printf("Invalid address family %i (SIOCGIFADDR)\n",
00434                        paddr->sin_family);
00435                 iapp_deinit(iapp);
00436                 return NULL;
00437         }
00438         iapp->own.s_addr = paddr->sin_addr.s_addr;
00439 
00440         if (ioctl(iapp->udp_sock, SIOCGIFBRDADDR, &ifr) != 0) {
00441                 perror("ioctl(SIOCGIFBRDADDR)");
00442                 iapp_deinit(iapp);
00443                 return NULL;
00444         }
00445         paddr = (struct sockaddr_in *) &ifr.ifr_addr;
00446         if (paddr->sin_family != AF_INET) {
00447                 printf("Invalid address family %i (SIOCGIFBRDADDR)\n",
00448                        paddr->sin_family);
00449                 iapp_deinit(iapp);
00450                 return NULL;
00451         }
00452         inet_aton(IAPP_MULTICAST, &iapp->multicast);
00453 
00454         os_memset(&uaddr, 0, sizeof(uaddr));
00455         uaddr.sin_family = AF_INET;
00456         uaddr.sin_port = htons(IAPP_UDP_PORT);
00457         if (bind(iapp->udp_sock, (struct sockaddr *) &uaddr,
00458                  sizeof(uaddr)) < 0) {
00459                 perror("bind[UDP]");
00460                 iapp_deinit(iapp);
00461                 return NULL;
00462         }
00463 
00464         os_memset(&mreq, 0, sizeof(mreq));
00465         mreq.imr_multiaddr = iapp->multicast;
00466         mreq.imr_address.s_addr = INADDR_ANY;
00467         mreq.imr_ifindex = 0;
00468         if (setsockopt(iapp->udp_sock, SOL_IP, IP_ADD_MEMBERSHIP, &mreq,
00469                        sizeof(mreq)) < 0) {
00470                 perror("setsockopt[UDP,IP_ADD_MEMBERSHIP]");
00471                 iapp_deinit(iapp);
00472                 return NULL;
00473         }
00474 
00475         iapp->packet_sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
00476         if (iapp->packet_sock < 0) {
00477                 perror("socket[PF_PACKET,SOCK_RAW]");
00478                 iapp_deinit(iapp);
00479                 return NULL;
00480         }
00481 
00482         os_memset(&addr, 0, sizeof(addr));
00483         addr.sll_family = AF_PACKET;
00484         addr.sll_ifindex = ifindex;
00485         if (bind(iapp->packet_sock, (struct sockaddr *) &addr,
00486                  sizeof(addr)) < 0) {
00487                 perror("bind[PACKET]");
00488                 iapp_deinit(iapp);
00489                 return NULL;
00490         }
00491 
00492         if (eloop_register_read_sock(iapp->udp_sock, iapp_receive_udp,
00493                                      iapp, NULL)) {
00494                 printf("Could not register read socket for IAPP.\n");
00495                 iapp_deinit(iapp);
00496                 return NULL;
00497         }
00498 
00499         printf("IEEE 802.11F (IAPP) using interface %s\n", iface);
00500 
00501         /* TODO: For levels 2 and 3: send RADIUS Initiate-Request, receive
00502          * RADIUS Initiate-Accept or Initiate-Reject. IAPP port should actually
00503          * be openned only after receiving Initiate-Accept. If Initiate-Reject
00504          * is received, IAPP is not started. */
00505 
00506         return iapp;
00507 }
00508 
00509 
00510 void iapp_deinit(struct iapp_data *iapp)
00511 {
00512         struct ip_mreqn mreq;
00513 
00514         if (iapp == NULL)
00515                 return;
00516 
00517         if (iapp->udp_sock >= 0) {
00518                 os_memset(&mreq, 0, sizeof(mreq));
00519                 mreq.imr_multiaddr = iapp->multicast;
00520                 mreq.imr_address.s_addr = INADDR_ANY;
00521                 mreq.imr_ifindex = 0;
00522                 if (setsockopt(iapp->udp_sock, SOL_IP, IP_DROP_MEMBERSHIP,
00523                                &mreq, sizeof(mreq)) < 0) {
00524                         perror("setsockopt[UDP,IP_DEL_MEMBERSHIP]");
00525                 }
00526 
00527                 eloop_unregister_read_sock(iapp->udp_sock);
00528                 close(iapp->udp_sock);
00529         }
00530         if (iapp->packet_sock >= 0) {
00531                 eloop_unregister_read_sock(iapp->packet_sock);
00532                 close(iapp->packet_sock);
00533         }
00534         os_free(iapp);
00535 }


wpa_supplicant
Author(s): Package maintained by Blaise Gassend
autogenerated on Thu Apr 24 2014 15:34:35