/*
* WPA Supplicant - Layer2 packet handling with Linux packet sockets
* Copyright (c) 2003-2015, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include <sys/ioctl.h>
#include <netpacket/packet.h>
#include <net/if.h>
#include <linux/filter.h>
#include "common.h"
#include "eloop.h"
#include "crypto/sha1.h"
#include "crypto/crypto.h"
#include "l2_packet.h"
struct l2_packet_data {
int fd; /* packet socket for EAPOL frames */
char ifname[IFNAMSIZ + 1];
int ifindex;
u8 own_addr[ETH_ALEN];
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len);
void *rx_callback_ctx;
int l2_hdr; /* whether to include layer 2 (Ethernet) header data
* buffers */
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
/* For working around Linux packet socket behavior and regression. */
int fd_br_rx;
int last_from_br, last_from_br_prev;
u8 last_hash[SHA1_MAC_LEN];
u8 last_hash_prev[SHA1_MAC_LEN];
unsigned int num_rx_br;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
};
/* Generated by 'sudo tcpdump -s 3000 -dd greater 278 and ip and udp and
* src port bootps and dst port bootpc'
*/
static struct sock_filter dhcp_sock_filter_insns[] = {
{ 0x80, 0, 0, 0x00000000 },
{ 0x35, 0, 12, 0x00000116 },
{ 0x28, 0, 0, 0x0000000c },
{ 0x15, 0, 10, 0x00000800 },
{ 0x30, 0, 0, 0x00000017 },
{ 0x15, 0, 8, 0x00000011 },
{ 0x28, 0, 0, 0x00000014 },
{ 0x45, 6, 0, 0x00001fff },
{ 0xb1, 0, 0, 0x0000000e },
{ 0x48, 0, 0, 0x0000000e },
{ 0x15, 0, 3, 0x00000043 },
{ 0x48, 0, 0, 0x00000010 },
{ 0x15, 0, 1, 0x00000044 },
{ 0x6, 0, 0, 0x00000bb8 },
{ 0x6, 0, 0, 0x00000000 },
};
static const struct sock_fprog dhcp_sock_filter = {
.len = ARRAY_SIZE(dhcp_sock_filter_insns),
.filter = dhcp_sock_filter_insns,
};
/* Generated by 'sudo tcpdump -dd -s 1500 multicast and ip6[6]=58' */
static struct sock_filter ndisc_sock_filter_insns[] = {
{ 0x30, 0, 0, 0x00000000 },
{ 0x45, 0, 5, 0x00000001 },
{ 0x28, 0, 0, 0x0000000c },
{ 0x15, 0, 3, 0x000086dd },
{ 0x30, 0, 0, 0x00000014 },
{ 0x15, 0, 1, 0x0000003a },
{ 0x6, 0, 0, 0x000005dc },
{ 0x6, 0, 0, 0x00000000 },
};
static const struct sock_fprog ndisc_sock_filter = {
.len = ARRAY_SIZE(ndisc_sock_filter_insns),
.filter = ndisc_sock_filter_insns,
};
int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
os_memcpy(addr, l2->own_addr, ETH_ALEN);
return 0;
}
int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
const u8 *buf, size_t len)
{
int ret;
if (TEST_FAIL())
return -1;
if (l2 == NULL)
return -1;
if (l2->l2_hdr) {
ret = send(l2->fd, buf, len, 0);
if (ret < 0)
wpa_printf(MSG_ERROR, "l2_packet_send - send: %s",
strerror(errno));
} else {
struct sockaddr_ll ll;
os_memset(&ll, 0, sizeof(ll));
ll.sll_family = AF_PACKET;
ll.sll_ifindex = l2->ifindex;
ll.sll_protocol = htons(proto);
ll.sll_halen = ETH_ALEN;
os_memcpy(ll.sll_addr, dst_addr, ETH_ALEN);
ret = sendto(l2->fd, buf, len, 0, (struct sockaddr *) &ll,
sizeof(ll));
if (ret < 0) {
wpa_printf(MSG_ERROR, "l2_packet_send - sendto: %s",
strerror(errno));
}
}
return ret;
}
static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
u8 buf[2300];
int res;
struct sockaddr_ll ll;
socklen_t fromlen;
os_memset(&ll, 0, sizeof(ll));
fromlen = sizeof(ll);
res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll,
&fromlen);
if (res < 0) {
wpa_printf(MSG_DEBUG, "l2_packet_receive - recvfrom: %s",
strerror(errno));
return;
}
wpa_printf(MSG_DEBUG, "%s: src=" MACSTR " len=%d",
__func__, MAC2STR(ll.sll_addr), (int) res);
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
if (l2->fd_br_rx >= 0) {
u8 hash[SHA1_MAC_LEN];
const u8 *addr[1];
size_t len[1];
/*
* Close the workaround socket if the kernel version seems to be
* able to deliver packets through the packet socket before
* authorization has been completed (in dormant state).
*/
if (l2->num_rx_br <= 1) {
wpa_printf(MSG_DEBUG,
"l2_packet_receive: Main packet socket for %s seems to have working RX - close workaround bridge socket",
l2->ifname);
eloop_unregister_read_sock(l2->fd_br_rx);
close(l2->fd_br_rx);
l2->fd_br_rx = -1;
}
addr[0] = buf;
len[0] = res;
sha1_vector(1, addr, len, hash);
if (l2->last_from_br &&
os_memcmp(hash, l2->last_hash, SHA1_MAC_LEN) == 0) {
wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX",
__func__);
return;
}
if (l2->last_from_br_prev &&
os_memcmp(hash, l2->last_hash_prev, SHA1_MAC_LEN) == 0) {
wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX(prev)",
__func__);
return;
}
os_memcpy(l2->last_hash_prev, l2->last_hash, SHA1_MAC_LEN);
l2->last_from_br_prev = l2->last_from_br;
os_memcpy(l2->last_hash, hash, SHA1_MAC_LEN);
}
l2->last_from_br = 0;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
static void l2_packet_receive_br(int sock, void *eloop_ctx, void *sock_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
u8 buf[2300];
int res;
struct sockaddr_ll ll;
socklen_t fromlen;
u8 hash[SHA1_MAC_LEN];
const u8 *addr[1];
size_t len[1];
l2->num_rx_br++;
os_memset(&ll, 0, sizeof(ll));
fromlen = sizeof(ll);
res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll,
&fromlen);
if (res < 0) {
wpa_printf(MSG_DEBUG, "l2_packet_receive_br - recvfrom: %s",
strerror(errno));
return;
}
wpa_printf(MSG_DEBUG, "%s: src=" MACSTR " len=%d",
__func__, MAC2STR(ll.sll_addr), (int) res);
if (os_memcmp(ll.sll_addr, l2->own_addr, ETH_ALEN) == 0) {
wpa_printf(MSG_DEBUG, "%s: Drop RX of own frame", __func__);
return;
}
addr[0] = buf;
len[0] = res;
sha1_vector(1, addr, len, hash);
if (!l2->last_from_br &&
os_memcmp(hash, l2->last_hash, SHA1_MAC_LEN) == 0) {
wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX", __func__);
return;
}
if (!l2->last_from_br_prev &&
os_memcmp(hash, l2->last_hash_prev, SHA1_MAC_LEN) == 0) {
wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX(prev)", __func__);
return;
}
os_memcpy(l2->last_hash_prev, l2->last_hash, SHA1_MAC_LEN);
l2->last_from_br_prev = l2->last_from_br;
l2->last_from_br = 1;
os_memcpy(l2->last_hash, hash, SHA1_MAC_LEN);
l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
struct l2_packet_data * l2_packet_init(
const char *ifname, const u8 *own_addr, unsigned short protocol,
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len),
void *rx_callback_ctx, int l2_hdr)
{
struct l2_packet_data *l2;
struct ifreq ifr;
struct sockaddr_ll ll;
l2 = os_zalloc(sizeof(struct l2_packet_data));
if (l2 == NULL)
return NULL;
os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
l2->rx_callback = rx_callback;
l2->rx_callback_ctx = rx_callback_ctx;
l2->l2_hdr = l2_hdr;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
l2->fd_br_rx = -1;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2->fd = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM,
htons(protocol));
if (l2->fd < 0) {
wpa_printf(MSG_ERROR, "%s: socket(PF_PACKET): %s",
__func__, strerror(errno));
os_free(l2);
return NULL;
}
os_memset(&ifr, 0, sizeof(ifr));
os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
if (ioctl(l2->fd, SIOCGIFINDEX, &ifr) < 0) {
wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFINDEX]: %s",
__func__, strerror(errno));
close(l2->fd);
os_free(l2);
return NULL;
}
l2->ifindex = ifr.ifr_ifindex;
os_memset(&ll, 0, sizeof(ll));
ll.sll_family = PF_PACKET;
ll.sll_ifindex = ifr.ifr_ifindex;
ll.sll_protocol = htons(protocol);
if (bind(l2->fd, (struct sockaddr *) &ll, sizeof(ll)) < 0) {
wpa_printf(MSG_ERROR, "%s: bind[PF_PACKET]: %s",
__func__, strerror(errno));
close(l2->fd);
os_free(l2);
return NULL;
}
if (ioctl(l2->fd, SIOCGIFHWADDR, &ifr) < 0) {
wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFHWADDR]: %s",
__func__, strerror(errno));
close(l2->fd);
os_free(l2);
return NULL;
}
os_memcpy(l2->own_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL);
return l2;
}
struct l2_packet_data * l2_packet_init_bridge(
const char *br_ifname, const char *ifname, const u8 *own_addr,
unsigned short protocol,
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len),
void *rx_callback_ctx, int l2_hdr)
{
struct l2_packet_data *l2;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
struct sock_filter ethertype_sock_filter_insns[] = {
/* Load ethertype */
BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 2 * ETH_ALEN),
/* Jump over next statement if ethertype does not match */
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, protocol, 0, 1),
/* Ethertype match - return all */
BPF_STMT(BPF_RET | BPF_K, ~0),
/* No match - drop */
BPF_STMT(BPF_RET | BPF_K, 0)
};
const struct sock_fprog ethertype_sock_filter = {
.len = ARRAY_SIZE(ethertype_sock_filter_insns),
.filter = ethertype_sock_filter_insns,
};
struct sockaddr_ll ll;
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
l2 = l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
rx_callback_ctx, l2_hdr);
if (!l2)
return NULL;
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
/*
* The Linux packet socket behavior has changed over the years and there
* is an inconvenient regression in it that breaks RX for a specific
* protocol from interfaces in a bridge when that interface is not in
* fully operation state (i.e., when in station mode and not completed
* authorization). To work around this, register ETH_P_ALL version of
* the packet socket bound to the real netdev and use socket filter to
* match the ethertype value. This version is less efficient, but
* required for functionality with many kernel version. If the main
* packet socket is found to be working, this less efficient version
* gets closed automatically.
*/
l2->fd_br_rx = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM,
htons(ETH_P_ALL));
if (l2->fd_br_rx < 0) {
wpa_printf(MSG_DEBUG, "%s: socket(PF_PACKET-fd_br_rx): %s",
__func__, strerror(errno));
/* try to continue without the workaround RX socket */
return l2;
}
os_memset(&ll, 0, sizeof(ll));
ll.sll_family = PF_PACKET;
ll.sll_ifindex = if_nametoindex(ifname);
ll.sll_protocol = htons(ETH_P_ALL);
if (bind(l2->fd_br_rx, (struct sockaddr *) &ll, sizeof(ll)) < 0) {
wpa_printf(MSG_DEBUG, "%s: bind[PF_PACKET-fd_br_rx]: %s",
__func__, strerror(errno));
/* try to continue without the workaround RX socket */
close(l2->fd_br_rx);
l2->fd_br_rx = -1;
return l2;
}
if (setsockopt(l2->fd_br_rx, SOL_SOCKET, SO_ATTACH_FILTER,
ðertype_sock_filter, sizeof(struct sock_fprog))) {
wpa_printf(MSG_DEBUG,
"l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s",
strerror(errno));
/* try to continue without the workaround RX socket */
close(l2->fd_br_rx);
l2->fd_br_rx = -1;
return l2;
}
eloop_register_read_sock(l2->fd_br_rx, l2_packet_receive_br, l2, NULL);
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
return l2;
}
void l2_packet_deinit(struct l2_packet_data *l2)
{
if (l2 == NULL)
return;
if (l2->fd >= 0) {
eloop_unregister_read_sock(l2->fd);
close(l2->fd);
}
#ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR
if (l2->fd_br_rx >= 0) {
eloop_unregister_read_sock(l2->fd_br_rx);
close(l2->fd_br_rx);
}
#endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */
os_free(l2);
}
int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
{
int s;
struct ifreq ifr;
struct sockaddr_in *saddr;
size_t res;
s = socket(PF_INET, SOCK_DGRAM, 0);
if (s < 0) {
wpa_printf(MSG_ERROR, "%s: socket: %s",
__func__, strerror(errno));
return -1;
}
os_memset(&ifr, 0, sizeof(ifr));
os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
if (errno != EADDRNOTAVAIL)
wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFADDR]: %s",
__func__, strerror(errno));
close(s);
return -1;
}
close(s);
saddr = aliasing_hide_typecast(&ifr.ifr_addr, struct sockaddr_in);
if (saddr->sin_family != AF_INET)
return -1;
res = os_strlcpy(buf, inet_ntoa(saddr->sin_addr), len);
if (res >= len)
return -1;
return 0;
}
void l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
}
int l2_packet_set_packet_filter(struct l2_packet_data *l2,
enum l2_packet_filter_type type)
{
const struct sock_fprog *sock_filter;
if (TEST_FAIL())
return -1;
switch (type) {
case L2_PACKET_FILTER_DHCP:
sock_filter = &dhcp_sock_filter;
break;
case L2_PACKET_FILTER_NDISC:
sock_filter = &ndisc_sock_filter;
break;
default:
return -1;
}
if (setsockopt(l2->fd, SOL_SOCKET, SO_ATTACH_FILTER,
sock_filter, sizeof(struct sock_fprog))) {
wpa_printf(MSG_ERROR,
"l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s",
strerror(errno));
return -1;
}
return 0;
}