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/*
* WPA Supplicant - Layer2 packet handling with FreeBSD
* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
* Copyright (c) 2005, Sam Leffler <sam@errno.com>
*
* 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"
#include <pcap.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#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;
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 data
* buffers */
};
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)
{
if (!l2->l2_hdr) {
int ret;
struct l2_ethhdr *eth = os_malloc(sizeof(*eth) + len);
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);
ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
os_free(eth);
return ret;
} else
return pcap_inject(l2->pcap, buf, len);
}
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);
}
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;
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;
}
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);
/*
* 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? */
}
}
eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
l2_packet_receive, l2, l2->pcap);
return 0;
}
static int eth_get(const char *device, u8 ea[ETH_ALEN])
{
struct if_msghdr *ifm;
struct sockaddr_dl *sdl;
u_char *p, *buf;
size_t len;
int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
return -1;
if ((buf = os_malloc(len)) == NULL)
return -1;
if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
os_free(buf);
return -1;
}
for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
ifm = (struct if_msghdr *)p;
sdl = (struct sockaddr_dl *)(ifm + 1);
if (ifm->ifm_type != RTM_IFINFO ||
(ifm->ifm_addrs & RTA_IFP) == 0)
continue;
if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
os_memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
continue;
os_memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
break;
}
os_free(buf);
if (p >= buf + len) {
errno = ESRCH;
return -1;
}
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;
if (eth_get(l2->ifname, l2->own_addr) < 0) {
fprintf(stderr, "Failed to get link-level address for "
"interface '%s'.\n", l2->ifname);
os_free(l2);
return NULL;
}
if (l2_packet_init_libpcap(l2, protocol)) {
os_free(l2);
return NULL;
}
return l2;
}
void l2_packet_deinit(struct l2_packet_data *l2)
{
if (l2 != NULL) {
if (l2->pcap) {
eloop_unregister_read_sock(
pcap_get_selectable_fd(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)
{
}
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