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/*
* WPA Supplicant - Layer2 packet handling with libpcap/libdnet and WinPcap
* Copyright (c) 2003-2006, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/

#include "includes.h"
#ifndef CONFIG_NATIVE_WINDOWS
#include <sys/ioctl.h>
#endif /* CONFIG_NATIVE_WINDOWS */
#include <pcap.h>
#ifndef CONFIG_WINPCAP
#include <dnet.h>
#endif /* CONFIG_WINPCAP */

#include "common.h"
#include "eloop.h"
#include "l2_packet.h"


static const u8 pae_group_addr[ETH_ALEN] =
{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x03 };

struct l2_packet_data {
pcap_t *pcap;
#ifdef CONFIG_WINPCAP
unsigned int num_fast_poll;
#else /* CONFIG_WINPCAP */
eth_t *eth;
#endif /* CONFIG_WINPCAP */
char ifname[100];
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 in calls
* to rx_callback */
};


int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
os_memcpy(addr, l2->own_addr, ETH_ALEN);
return 0;
}


#ifndef CONFIG_WINPCAP
static int l2_packet_init_libdnet(struct l2_packet_data *l2)
{
eth_addr_t own_addr;

l2->eth = eth_open(l2->ifname);
if (!l2->eth) {
printf("Failed to open interface '%s'.\n", l2->ifname);
perror("eth_open");
return -1;
}

if (eth_get(l2->eth, &own_addr) < 0) {
printf("Failed to get own hw address from interface '%s'.\n",
l2->ifname);
perror("eth_get");
eth_close(l2->eth);
l2->eth = NULL;
return -1;
}
os_memcpy(l2->own_addr, own_addr.data, ETH_ALEN);

return 0;
}
#endif /* CONFIG_WINPCAP */


int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
const u8 *buf, size_t len)
{
int ret;
struct l2_ethhdr *eth;

if (l2 == NULL)
return -1;

if (l2->l2_hdr) {
#ifdef CONFIG_WINPCAP
ret = pcap_sendpacket(l2->pcap, buf, len);
#else /* CONFIG_WINPCAP */
ret = eth_send(l2->eth, buf, len);
#endif /* CONFIG_WINPCAP */
} else {
size_t mlen = sizeof(*eth) + len;
eth = os_malloc(mlen);
if (eth == NULL)
return -1;

os_memcpy(eth->h_dest, dst_addr, ETH_ALEN);
os_memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
eth->h_proto = htons(proto);
os_memcpy(eth + 1, buf, len);

#ifdef CONFIG_WINPCAP
ret = pcap_sendpacket(l2->pcap, (u8 *) eth, mlen);
#else /* CONFIG_WINPCAP */
ret = eth_send(l2->eth, (u8 *) eth, mlen);
#endif /* CONFIG_WINPCAP */

os_free(eth);
}

return ret;
}


#ifndef CONFIG_WINPCAP
static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
pcap_t *pcap = sock_ctx;
struct pcap_pkthdr hdr;
const u_char *packet;
struct l2_ethhdr *ethhdr;
unsigned char *buf;
size_t len;

packet = pcap_next(pcap, &hdr);

if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
return;

ethhdr = (struct l2_ethhdr *) packet;
if (l2->l2_hdr) {
buf = (unsigned char *) ethhdr;
len = hdr.caplen;
} else {
buf = (unsigned char *) (ethhdr + 1);
len = hdr.caplen - sizeof(*ethhdr);
}
l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
}
#endif /* CONFIG_WINPCAP */


#ifdef CONFIG_WINPCAP
static void l2_packet_receive_cb(u_char *user, const struct pcap_pkthdr *hdr,
const u_char *pkt_data)
{
struct l2_packet_data *l2 = (struct l2_packet_data *) user;
struct l2_ethhdr *ethhdr;
unsigned char *buf;
size_t len;

if (pkt_data == NULL || hdr->caplen < sizeof(*ethhdr))
return;

ethhdr = (struct l2_ethhdr *) pkt_data;
if (l2->l2_hdr) {
buf = (unsigned char *) ethhdr;
len = hdr->caplen;
} else {
buf = (unsigned char *) (ethhdr + 1);
len = hdr->caplen - sizeof(*ethhdr);
}
l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
/*
* Use shorter poll interval for 3 seconds to reduce latency during key
* handshake.
*/
l2->num_fast_poll = 3 * 50;
}


static void l2_packet_receive_timeout(void *eloop_ctx, void *timeout_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
pcap_t *pcap = timeout_ctx;
int timeout;

if (l2->num_fast_poll > 0) {
timeout = 20000;
l2->num_fast_poll--;
} else
timeout = 100000;

/* Register new timeout before calling l2_packet_receive() since
* receive handler may free this l2_packet instance (which will
* cancel this timeout). */
eloop_register_timeout(0, timeout, l2_packet_receive_timeout,
l2, pcap);
pcap_dispatch(pcap, 10, l2_packet_receive_cb, (u_char *) l2);
}
#endif /* CONFIG_WINPCAP */


static int l2_packet_init_libpcap(struct l2_packet_data *l2,
unsigned short protocol)
{
bpf_u_int32 pcap_maskp, pcap_netp;
char pcap_filter[200], pcap_err[PCAP_ERRBUF_SIZE];
struct bpf_program pcap_fp;

#ifdef CONFIG_WINPCAP
char ifname[128];
os_snprintf(ifname, sizeof(ifname), "\\Device\\NPF_%s", l2->ifname);
pcap_lookupnet(ifname, &pcap_netp, &pcap_maskp, pcap_err);
l2->pcap = pcap_open_live(ifname, 2500, 0, 10, pcap_err);
if (l2->pcap == NULL) {
fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
fprintf(stderr, "ifname='%s'\n", ifname);
return -1;
}
if (pcap_setnonblock(l2->pcap, 1, pcap_err) < 0)
fprintf(stderr, "pcap_setnonblock: %s\n",
pcap_geterr(l2->pcap));
#else /* CONFIG_WINPCAP */
pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
if (l2->pcap == NULL) {
fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
fprintf(stderr, "ifname='%s'\n", l2->ifname);
return -1;
}
if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
fprintf(stderr, "pcap_set_datalink(DLT_EN10MB): %s\n",
pcap_geterr(l2->pcap));
return -1;
}
#endif /* CONFIG_WINPCAP */
os_snprintf(pcap_filter, sizeof(pcap_filter),
"not ether src " MACSTR " and "
"( ether dst " MACSTR " or ether dst " MACSTR " ) and "
"ether proto 0x%x",
MAC2STR(l2->own_addr), /* do not receive own packets */
MAC2STR(l2->own_addr), MAC2STR(pae_group_addr),
protocol);
if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
return -1;
}

if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
return -1;
}

pcap_freecode(&pcap_fp);
#ifdef BIOCIMMEDIATE
/*
* When libpcap uses BPF we must enable "immediate mode" to
* receive frames right away; otherwise the system may
* buffer them for us.
*/
{
unsigned int on = 1;
if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) {
fprintf(stderr, "%s: cannot enable immediate mode on "
"interface %s: %s\n",
__func__, l2->ifname, strerror(errno));
/* XXX should we fail? */
}
}
#endif /* BIOCIMMEDIATE */

#ifdef CONFIG_WINPCAP
eloop_register_timeout(0, 100000, l2_packet_receive_timeout,
l2, l2->pcap);
#else /* CONFIG_WINPCAP */
eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
l2_packet_receive, l2, l2->pcap);
#endif /* CONFIG_WINPCAP */

return 0;
}


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;

l2 = os_zalloc(sizeof(struct l2_packet_data));
if (l2 == NULL)
return NULL;
os_strncpy(l2->ifname, ifname, sizeof(l2->ifname));
l2->rx_callback = rx_callback;
l2->rx_callback_ctx = rx_callback_ctx;
l2->l2_hdr = l2_hdr;

#ifdef CONFIG_WINPCAP
if (own_addr)
os_memcpy(l2->own_addr, own_addr, ETH_ALEN);
#else /* CONFIG_WINPCAP */
if (l2_packet_init_libdnet(l2))
return NULL;
#endif /* CONFIG_WINPCAP */

if (l2_packet_init_libpcap(l2, protocol)) {
#ifndef CONFIG_WINPCAP
eth_close(l2->eth);
#endif /* CONFIG_WINPCAP */
os_free(l2);
return NULL;
}

return l2;
}


void l2_packet_deinit(struct l2_packet_data *l2)
{
if (l2 == NULL)
return;

#ifdef CONFIG_WINPCAP
eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap);
#else /* CONFIG_WINPCAP */
if (l2->eth)
eth_close(l2->eth);
eloop_unregister_read_sock(pcap_get_selectable_fd(l2->pcap));
#endif /* CONFIG_WINPCAP */
if (l2->pcap)
pcap_close(l2->pcap);
os_free(l2);
}


int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
{
pcap_if_t *devs, *dev;
struct pcap_addr *addr;
struct sockaddr_in *saddr;
int found = 0;
char err[PCAP_ERRBUF_SIZE + 1];

if (pcap_findalldevs(&devs, err) < 0) {
wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
return -1;
}

for (dev = devs; dev && !found; dev = dev->next) {
if (os_strcmp(dev->name, l2->ifname) != 0)
continue;

addr = dev->addresses;
while (addr) {
saddr = (struct sockaddr_in *) addr->addr;
if (saddr && saddr->sin_family == AF_INET) {
os_snprintf(buf, len, "%s",
inet_ntoa(saddr->sin_addr));
found = 1;
break;
}
addr = addr->next;
}
}

pcap_freealldevs(devs);

return found ? 0 : -1;
}


void l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
#ifdef CONFIG_WINPCAP
/*
* Use shorter poll interval for 3 seconds to reduce latency during key
* handshake.
*/
l2->num_fast_poll = 3 * 50;
eloop_cancel_timeout(l2_packet_receive_timeout, l2, l2->pcap);
eloop_register_timeout(0, 10000, l2_packet_receive_timeout,
l2, l2->pcap);
#endif /* CONFIG_WINPCAP */
}
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