hostap/src/ap/iapp.c

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/*
* hostapd / IEEE 802.11F-2003 Inter-Access Point Protocol (IAPP)
* Copyright (c) 2002-2007, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*
* Note: IEEE 802.11F-2003 was a experimental use specification. It has expired
* and IEEE has withdrawn it. In other words, it is likely better to look at
* using some other mechanism for AP-to-AP communication than extending the
* implementation here.
*/
/* TODO:
* Level 1: no administrative or security support
* (e.g., static BSSID to IP address mapping in each AP)
* Level 2: support for dynamic mapping of BSSID to IP address
* Level 3: support for encryption and authentication of IAPP messages
* - add support for MOVE-notify and MOVE-response (this requires support for
* finding out IP address for previous AP using RADIUS)
* - add support for Send- and ACK-Security-Block to speedup IEEE 802.1X during
* reassociation to another AP
* - implement counters etc. for IAPP MIB
* - verify endianness of fields in IAPP messages; are they big-endian as
* used here?
* - RADIUS connection for AP registration and BSSID to IP address mapping
* - TCP connection for IAPP MOVE, CACHE
* - broadcast ESP for IAPP ADD-notify
* - ESP for IAPP MOVE messages
* - security block sending/processing
* - IEEE 802.11 context transfer
*/
#include "utils/includes.h"
#include <net/if.h>
#include <sys/ioctl.h>
#ifdef USE_KERNEL_HEADERS
#include <linux/if_packet.h>
#else /* USE_KERNEL_HEADERS */
#include <netpacket/packet.h>
#endif /* USE_KERNEL_HEADERS */
#include "utils/common.h"
#include "utils/eloop.h"
#include "common/ieee802_11_defs.h"
#include "hostapd.h"
#include "ap_config.h"
#include "ieee802_11.h"
#include "sta_info.h"
#include "iapp.h"
#define IAPP_MULTICAST "224.0.1.178"
#define IAPP_UDP_PORT 3517
#define IAPP_TCP_PORT 3517
struct iapp_hdr {
u8 version;
u8 command;
be16 identifier;
be16 length;
/* followed by length-6 octets of data */
} __attribute__ ((packed));
#define IAPP_VERSION 0
enum IAPP_COMMAND {
IAPP_CMD_ADD_notify = 0,
IAPP_CMD_MOVE_notify = 1,
IAPP_CMD_MOVE_response = 2,
IAPP_CMD_Send_Security_Block = 3,
IAPP_CMD_ACK_Security_Block = 4,
IAPP_CMD_CACHE_notify = 5,
IAPP_CMD_CACHE_response = 6,
};
/* ADD-notify - multicast UDP on the local LAN */
struct iapp_add_notify {
u8 addr_len; /* ETH_ALEN */
u8 reserved;
u8 mac_addr[ETH_ALEN];
be16 seq_num;
} __attribute__ ((packed));
/* Layer 2 Update frame (802.2 Type 1 LLC XID Update response) */
struct iapp_layer2_update {
u8 da[ETH_ALEN]; /* broadcast */
u8 sa[ETH_ALEN]; /* STA addr */
be16 len; /* 6 */
u8 dsap; /* null DSAP address */
u8 ssap; /* null SSAP address, CR=Response */
u8 control;
u8 xid_info[3];
} __attribute__ ((packed));
/* MOVE-notify - unicast TCP */
struct iapp_move_notify {
u8 addr_len; /* ETH_ALEN */
u8 reserved;
u8 mac_addr[ETH_ALEN];
u16 seq_num;
u16 ctx_block_len;
/* followed by ctx_block_len bytes */
} __attribute__ ((packed));
/* MOVE-response - unicast TCP */
struct iapp_move_response {
u8 addr_len; /* ETH_ALEN */
u8 status;
u8 mac_addr[ETH_ALEN];
u16 seq_num;
u16 ctx_block_len;
/* followed by ctx_block_len bytes */
} __attribute__ ((packed));
enum {
IAPP_MOVE_SUCCESSFUL = 0,
IAPP_MOVE_DENIED = 1,
IAPP_MOVE_STALE_MOVE = 2,
};
/* CACHE-notify */
struct iapp_cache_notify {
u8 addr_len; /* ETH_ALEN */
u8 reserved;
u8 mac_addr[ETH_ALEN];
u16 seq_num;
u8 current_ap[ETH_ALEN];
u16 ctx_block_len;
/* ctx_block_len bytes of context block followed by 16-bit context
* timeout */
} __attribute__ ((packed));
/* CACHE-response - unicast TCP */
struct iapp_cache_response {
u8 addr_len; /* ETH_ALEN */
u8 status;
u8 mac_addr[ETH_ALEN];
u16 seq_num;
} __attribute__ ((packed));
enum {
IAPP_CACHE_SUCCESSFUL = 0,
IAPP_CACHE_STALE_CACHE = 1,
};
/* Send-Security-Block - unicast TCP */
struct iapp_send_security_block {
u8 iv[8];
u16 sec_block_len;
/* followed by sec_block_len bytes of security block */
} __attribute__ ((packed));
/* ACK-Security-Block - unicast TCP */
struct iapp_ack_security_block {
u8 iv[8];
u8 new_ap_ack_authenticator[48];
} __attribute__ ((packed));
struct iapp_data {
struct hostapd_data *hapd;
u16 identifier; /* next IAPP identifier */
struct in_addr own, multicast;
int udp_sock;
int packet_sock;
};
static void iapp_send_add(struct iapp_data *iapp, u8 *mac_addr, u16 seq_num)
{
char buf[128];
struct iapp_hdr *hdr;
struct iapp_add_notify *add;
struct sockaddr_in addr;
/* Send IAPP ADD-notify to remove possible association from other APs
*/
hdr = (struct iapp_hdr *) buf;
hdr->version = IAPP_VERSION;
hdr->command = IAPP_CMD_ADD_notify;
hdr->identifier = host_to_be16(iapp->identifier++);
hdr->length = host_to_be16(sizeof(*hdr) + sizeof(*add));
add = (struct iapp_add_notify *) (hdr + 1);
add->addr_len = ETH_ALEN;
add->reserved = 0;
os_memcpy(add->mac_addr, mac_addr, ETH_ALEN);
add->seq_num = host_to_be16(seq_num);
os_memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = iapp->multicast.s_addr;
addr.sin_port = htons(IAPP_UDP_PORT);
if (sendto(iapp->udp_sock, buf, (char *) (add + 1) - buf, 0,
(struct sockaddr *) &addr, sizeof(addr)) < 0)
wpa_printf(MSG_INFO, "sendto[IAPP-ADD]: %s", strerror(errno));
}
static void iapp_send_layer2_update(struct iapp_data *iapp, u8 *addr)
{
struct iapp_layer2_update msg;
/* Send Level 2 Update Frame to update forwarding tables in layer 2
* bridge devices */
/* 802.2 Type 1 Logical Link Control (LLC) Exchange Identifier (XID)
* Update response frame; IEEE Std 802.2-1998, 5.4.1.2.1 */
os_memset(msg.da, 0xff, ETH_ALEN);
os_memcpy(msg.sa, addr, ETH_ALEN);
msg.len = host_to_be16(6);
msg.dsap = 0; /* NULL DSAP address */
msg.ssap = 0x01; /* NULL SSAP address, CR Bit: Response */
msg.control = 0xaf; /* XID response lsb.1111F101.
* F=0 (no poll command; unsolicited frame) */
msg.xid_info[0] = 0x81; /* XID format identifier */
msg.xid_info[1] = 1; /* LLC types/classes: Type 1 LLC */
msg.xid_info[2] = 1 << 1; /* XID sender's receive window size (RW)
* FIX: what is correct RW with 802.11? */
if (send(iapp->packet_sock, &msg, sizeof(msg), 0) < 0)
wpa_printf(MSG_INFO, "send[L2 Update]: %s", strerror(errno));
}
/**
* iapp_new_station - IAPP processing for a new STA
* @iapp: IAPP data
* @sta: The associated station
*/
void iapp_new_station(struct iapp_data *iapp, struct sta_info *sta)
{
u16 seq = 0; /* TODO */
if (iapp == NULL)
return;
/* IAPP-ADD.request(MAC Address, Sequence Number, Timeout) */
hostapd_logger(iapp->hapd, sta->addr, HOSTAPD_MODULE_IAPP,
HOSTAPD_LEVEL_DEBUG, "IAPP-ADD.request(seq=%d)", seq);
iapp_send_layer2_update(iapp, sta->addr);
iapp_send_add(iapp, sta->addr, seq);
/* TODO: If this was reassociation:
* IAPP-MOVE.request(MAC Address, Sequence Number, Old AP,
* Context Block, Timeout)
* TODO: Send IAPP-MOVE to the old AP; Map Old AP BSSID to
* IP address */
}
static void iapp_process_add_notify(struct iapp_data *iapp,
struct sockaddr_in *from,
struct iapp_hdr *hdr, int len)
{
struct iapp_add_notify *add = (struct iapp_add_notify *) (hdr + 1);
struct sta_info *sta;
if (len != sizeof(*add)) {
wpa_printf(MSG_INFO, "Invalid IAPP-ADD packet length %d (expected %lu)",
len, (unsigned long) sizeof(*add));
return;
}
sta = ap_get_sta(iapp->hapd, add->mac_addr);
/* IAPP-ADD.indication(MAC Address, Sequence Number) */
hostapd_logger(iapp->hapd, add->mac_addr, HOSTAPD_MODULE_IAPP,
HOSTAPD_LEVEL_INFO,
"Received IAPP ADD-notify (seq# %d) from %s:%d%s",
be_to_host16(add->seq_num),
inet_ntoa(from->sin_addr), ntohs(from->sin_port),
sta ? "" : " (STA not found)");
if (!sta)
return;
/* TODO: could use seq_num to try to determine whether last association
* to this AP is newer than the one advertised in IAPP-ADD. Although,
* this is not really a reliable verification. */
hostapd_logger(iapp->hapd, add->mac_addr, HOSTAPD_MODULE_IAPP,
HOSTAPD_LEVEL_DEBUG,
"Removing STA due to IAPP ADD-notify");
ap_sta_disconnect(iapp->hapd, sta, NULL, 0);
}
/**
* iapp_receive_udp - Process IAPP UDP frames
* @sock: File descriptor for the socket
* @eloop_ctx: IAPP data (struct iapp_data *)
* @sock_ctx: Not used
*/
static void iapp_receive_udp(int sock, void *eloop_ctx, void *sock_ctx)
{
struct iapp_data *iapp = eloop_ctx;
int len, hlen;
unsigned char buf[128];
struct sockaddr_in from;
socklen_t fromlen;
struct iapp_hdr *hdr;
/* Handle incoming IAPP frames (over UDP/IP) */
fromlen = sizeof(from);
len = recvfrom(iapp->udp_sock, buf, sizeof(buf), 0,
(struct sockaddr *) &from, &fromlen);
if (len < 0) {
wpa_printf(MSG_INFO, "iapp_receive_udp - recvfrom: %s",
strerror(errno));
return;
}
if (from.sin_addr.s_addr == iapp->own.s_addr)
return; /* ignore own IAPP messages */
hostapd_logger(iapp->hapd, NULL, HOSTAPD_MODULE_IAPP,
HOSTAPD_LEVEL_DEBUG,
"Received %d byte IAPP frame from %s%s\n",
len, inet_ntoa(from.sin_addr),
len < (int) sizeof(*hdr) ? " (too short)" : "");
if (len < (int) sizeof(*hdr))
return;
hdr = (struct iapp_hdr *) buf;
hlen = be_to_host16(hdr->length);
hostapd_logger(iapp->hapd, NULL, HOSTAPD_MODULE_IAPP,
HOSTAPD_LEVEL_DEBUG,
"RX: version=%d command=%d id=%d len=%d\n",
hdr->version, hdr->command,
be_to_host16(hdr->identifier), hlen);
if (hdr->version != IAPP_VERSION) {
wpa_printf(MSG_INFO, "Dropping IAPP frame with unknown version %d",
hdr->version);
return;
}
if (hlen > len) {
wpa_printf(MSG_INFO, "Underflow IAPP frame (hlen=%d len=%d)",
hlen, len);
return;
}
if (hlen < len) {
wpa_printf(MSG_INFO, "Ignoring %d extra bytes from IAPP frame",
len - hlen);
len = hlen;
}
switch (hdr->command) {
case IAPP_CMD_ADD_notify:
iapp_process_add_notify(iapp, &from, hdr, hlen - sizeof(*hdr));
break;
case IAPP_CMD_MOVE_notify:
/* TODO: MOVE is using TCP; so move this to TCP handler once it
* is implemented.. */
/* IAPP-MOVE.indication(MAC Address, New BSSID,
* Sequence Number, AP Address, Context Block) */
/* TODO: process */
break;
default:
wpa_printf(MSG_INFO, "Unknown IAPP command %d", hdr->command);
break;
}
}
struct iapp_data * iapp_init(struct hostapd_data *hapd, const char *iface)
{
struct ifreq ifr;
struct sockaddr_ll addr;
int ifindex;
struct sockaddr_in *paddr, uaddr;
struct iapp_data *iapp;
struct ip_mreqn mreq;
iapp = os_zalloc(sizeof(*iapp));
if (iapp == NULL)
return NULL;
iapp->hapd = hapd;
iapp->udp_sock = iapp->packet_sock = -1;
/* TODO:
* open socket for sending and receiving IAPP frames over TCP
*/
iapp->udp_sock = socket(PF_INET, SOCK_DGRAM, 0);
if (iapp->udp_sock < 0) {
wpa_printf(MSG_INFO, "iapp_init - socket[PF_INET,SOCK_DGRAM]: %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
os_memset(&ifr, 0, sizeof(ifr));
os_strlcpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));
if (ioctl(iapp->udp_sock, SIOCGIFINDEX, &ifr) != 0) {
wpa_printf(MSG_INFO, "iapp_init - ioctl(SIOCGIFINDEX): %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
ifindex = ifr.ifr_ifindex;
if (ioctl(iapp->udp_sock, SIOCGIFADDR, &ifr) != 0) {
wpa_printf(MSG_INFO, "iapp_init - ioctl(SIOCGIFADDR): %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
paddr = (struct sockaddr_in *) &ifr.ifr_addr;
if (paddr->sin_family != AF_INET) {
wpa_printf(MSG_INFO, "IAPP: Invalid address family %i (SIOCGIFADDR)",
paddr->sin_family);
iapp_deinit(iapp);
return NULL;
}
iapp->own.s_addr = paddr->sin_addr.s_addr;
if (ioctl(iapp->udp_sock, SIOCGIFBRDADDR, &ifr) != 0) {
wpa_printf(MSG_INFO, "iapp_init - ioctl(SIOCGIFBRDADDR): %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
paddr = (struct sockaddr_in *) &ifr.ifr_addr;
if (paddr->sin_family != AF_INET) {
wpa_printf(MSG_INFO, "Invalid address family %i (SIOCGIFBRDADDR)",
paddr->sin_family);
iapp_deinit(iapp);
return NULL;
}
inet_aton(IAPP_MULTICAST, &iapp->multicast);
os_memset(&uaddr, 0, sizeof(uaddr));
uaddr.sin_family = AF_INET;
uaddr.sin_port = htons(IAPP_UDP_PORT);
if (bind(iapp->udp_sock, (struct sockaddr *) &uaddr,
sizeof(uaddr)) < 0) {
wpa_printf(MSG_INFO, "iapp_init - bind[UDP]: %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
os_memset(&mreq, 0, sizeof(mreq));
mreq.imr_multiaddr = iapp->multicast;
mreq.imr_address.s_addr = INADDR_ANY;
mreq.imr_ifindex = 0;
if (setsockopt(iapp->udp_sock, SOL_IP, IP_ADD_MEMBERSHIP, &mreq,
sizeof(mreq)) < 0) {
wpa_printf(MSG_INFO, "iapp_init - setsockopt[UDP,IP_ADD_MEMBERSHIP]: %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
iapp->packet_sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (iapp->packet_sock < 0) {
wpa_printf(MSG_INFO, "iapp_init - socket[PF_PACKET,SOCK_RAW]: %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
os_memset(&addr, 0, sizeof(addr));
addr.sll_family = AF_PACKET;
addr.sll_ifindex = ifindex;
if (bind(iapp->packet_sock, (struct sockaddr *) &addr,
sizeof(addr)) < 0) {
wpa_printf(MSG_INFO, "iapp_init - bind[PACKET]: %s",
strerror(errno));
iapp_deinit(iapp);
return NULL;
}
if (eloop_register_read_sock(iapp->udp_sock, iapp_receive_udp,
iapp, NULL)) {
wpa_printf(MSG_INFO, "Could not register read socket for IAPP");
iapp_deinit(iapp);
return NULL;
}
wpa_printf(MSG_INFO, "IEEE 802.11F (IAPP) using interface %s", iface);
/* TODO: For levels 2 and 3: send RADIUS Initiate-Request, receive
* RADIUS Initiate-Accept or Initiate-Reject. IAPP port should actually
* be openned only after receiving Initiate-Accept. If Initiate-Reject
* is received, IAPP is not started. */
return iapp;
}
void iapp_deinit(struct iapp_data *iapp)
{
struct ip_mreqn mreq;
if (iapp == NULL)
return;
if (iapp->udp_sock >= 0) {
os_memset(&mreq, 0, sizeof(mreq));
mreq.imr_multiaddr = iapp->multicast;
mreq.imr_address.s_addr = INADDR_ANY;
mreq.imr_ifindex = 0;
if (setsockopt(iapp->udp_sock, SOL_IP, IP_DROP_MEMBERSHIP,
&mreq, sizeof(mreq)) < 0) {
wpa_printf(MSG_INFO, "iapp_deinit - setsockopt[UDP,IP_DEL_MEMBERSHIP]: %s",
strerror(errno));
}
eloop_unregister_read_sock(iapp->udp_sock);
close(iapp->udp_sock);
}
if (iapp->packet_sock >= 0) {
eloop_unregister_read_sock(iapp->packet_sock);
close(iapp->packet_sock);
}
os_free(iapp);
}