294 lines
6.8 KiB
C
294 lines
6.8 KiB
C
/* $NetBSD: l2_packet.c,v 1.4 2006/05/11 08:44:07 mrg Exp $ */
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/*
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* WPA Supplicant - Layer2 packet handling
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* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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* Copyright (c) 2005, Sam Leffler <sam@errno.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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/*
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* NetBSD-specific implementation.
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*
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* Based on:
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* $FreeBSD: src/usr.sbin/wpa/l2_packet.c,v 1.3 2006/03/07 05:54:19 sam Exp $
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*/
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <pcap.h>
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#include "common.h"
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#include "eloop.h"
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#include "l2_packet.h"
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struct l2_packet_data {
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pcap_t *pcap;
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char ifname[100];
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u8 own_addr[ETH_ALEN];
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void (*rx_callback)(void *ctx, const u8 *src_addr,
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const u8 *buf, size_t len);
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void *rx_callback_ctx;
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int rx_l2_hdr; /* whether to include layer 2 (Ethernet) header in calls
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* to rx_callback */
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};
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int
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l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
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{
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memcpy(addr, l2->own_addr, ETH_ALEN);
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return 0;
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}
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void
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l2_packet_set_rx_l2_hdr(struct l2_packet_data *l2, int rx_l2_hdr)
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{
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l2->rx_l2_hdr = rx_l2_hdr;
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}
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int
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l2_packet_send(struct l2_packet_data *l2,
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const u8 *dst_addr, u16 proto, const u8 *buf, size_t len)
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{
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if (!l2->rx_l2_hdr) {
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int ret;
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struct l2_ethhdr *eth = malloc(sizeof(*eth) + len);
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if (eth == NULL)
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return -1;
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memcpy(eth->h_dest, dst_addr, ETH_ALEN);
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memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
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eth->h_proto = htons(proto);
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memcpy(eth + 1, buf, len);
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ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
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free(eth);
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return ret;
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} else
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return pcap_inject(l2->pcap, buf, len);
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}
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int
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l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
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{
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pcap_if_t *devs, *dev;
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struct pcap_addr *addr;
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struct sockaddr_in *saddr;
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int found = 0;
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char err[PCAP_ERRBUF_SIZE + 1];
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if (pcap_findalldevs(&devs, err) < 0) {
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wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
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return -1;
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}
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for (dev = devs; dev && !found; dev = dev->next) {
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if (strcmp(dev->name, l2->ifname) != 0)
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continue;
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addr = dev->addresses;
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while (addr) {
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saddr = (struct sockaddr_in *) addr->addr;
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if (saddr && saddr->sin_family == AF_INET) {
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snprintf(buf, len, "%s",
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inet_ntoa(saddr->sin_addr));
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found = 1;
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break;
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}
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addr = addr->next;
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}
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}
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pcap_freealldevs(devs);
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return found ? 0 : -1;
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}
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void
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l2_packet_notify_auth_start(struct l2_packet_data *l2)
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{
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}
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static void
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l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
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{
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struct l2_packet_data *l2 = eloop_ctx;
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pcap_t *pcap = sock_ctx;
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struct pcap_pkthdr hdr;
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const u_char *packet;
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struct l2_ethhdr *ethhdr;
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unsigned char *buf;
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size_t len;
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packet = pcap_next(pcap, &hdr);
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if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
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return;
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ethhdr = (struct l2_ethhdr *) packet;
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if (l2->rx_l2_hdr) {
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buf = (unsigned char *) ethhdr;
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len = hdr.caplen;
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} else {
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buf = (unsigned char *) (ethhdr + 1);
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len = hdr.caplen - sizeof(*ethhdr);
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}
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l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
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}
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static int
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l2_packet_init_libpcap(struct l2_packet_data *l2, unsigned short protocol)
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{
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bpf_u_int32 pcap_maskp, pcap_netp;
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char pcap_filter[100], pcap_err[PCAP_ERRBUF_SIZE];
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struct bpf_program pcap_fp;
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pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
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l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
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if (l2->pcap == NULL) {
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fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
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fprintf(stderr, "ifname='%s'\n", l2->ifname);
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return -1;
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}
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if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
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pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
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fprintf(stderr, "pcap_set_datalinke(DLT_EN10MB): %s\n",
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pcap_geterr(l2->pcap));
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return -1;
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}
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snprintf(pcap_filter, sizeof(pcap_filter),
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"ether dst " MACSTR " and ether proto 0x%x",
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MAC2STR(l2->own_addr), protocol);
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if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
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fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
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return -1;
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}
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if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
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fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
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return -1;
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}
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pcap_freecode(&pcap_fp);
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/*
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* When libpcap uses BPF we must enable "immediate mode" to
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* receive frames right away; otherwise the system may
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* buffer them for us.
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*/
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{ unsigned int on = 1;
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if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) {
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fprintf(stderr, "%s: cannot enable immediate mode on "
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"interface %s: %s\n",
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__func__, l2->ifname, strerror(errno));
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/* XXX should we fail? */
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}
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}
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eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
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l2_packet_receive, l2, l2->pcap);
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return 0;
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}
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static int
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eth_get(const char *device, u8 ea[ETH_ALEN])
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{
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struct if_msghdr *ifm;
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struct sockaddr_dl *sdl;
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u_char *p, *buf;
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size_t len;
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int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
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if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
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return -1;
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if ((buf = malloc(len)) == NULL)
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return -1;
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if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
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free(buf);
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return -1;
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}
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for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
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ifm = (struct if_msghdr *)p;
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sdl = (struct sockaddr_dl *)(ifm + 1);
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if (ifm->ifm_type != RTM_IFINFO ||
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(ifm->ifm_addrs & RTA_IFP) == 0)
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continue;
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if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
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memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
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continue;
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memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
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break;
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}
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if (p >= buf + len) {
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errno = ESRCH;
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free(buf);
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return -1;
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}
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free(buf);
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return 0;
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}
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struct l2_packet_data *
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l2_packet_init(const char *ifname, const u8 *own_addr, unsigned short protocol,
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void (*rx_callback)(void *ctx, const u8 *src_addr,
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const u8 *buf, size_t len),
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void *rx_callback_ctx, int rx_l2_hdr)
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{
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struct l2_packet_data *l2;
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l2 = malloc(sizeof(struct l2_packet_data));
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if (l2 == NULL)
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return NULL;
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memset(l2, 0, sizeof(*l2));
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strncpy(l2->ifname, ifname, sizeof(l2->ifname));
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l2->rx_callback = rx_callback;
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l2->rx_callback_ctx = rx_callback_ctx;
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l2->rx_l2_hdr = rx_l2_hdr;
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if (eth_get(l2->ifname, l2->own_addr) < 0) {
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fprintf(stderr, "Failed to get link-level address for "
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"interface '%s'.\n", l2->ifname);
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free(l2);
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return NULL;
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}
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if (l2_packet_init_libpcap(l2, protocol) != 0) {
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free(l2);
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return NULL;
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}
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return l2;
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}
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void
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l2_packet_deinit(struct l2_packet_data *l2)
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{
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if (l2 != NULL) {
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if (l2->pcap)
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pcap_close(l2->pcap);
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free(l2);
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}
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}
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