+++ /dev/null
-/*
- * WPA Supplicant - Layer2 packet handling with WinPcap RX thread
- * 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.
- *
- * This l2_packet implementation is explicitly for WinPcap and Windows events.
- * l2_packet_pcap.c has support for WinPcap, but it requires polling to receive
- * frames which means relatively long latency for EAPOL RX processing. The
- * implementation here uses a separate thread to allow WinPcap to be receiving
- * all the time to reduce latency for EAPOL receiving from about 100 ms to 3 ms
- * when comparing l2_packet_pcap.c to l2_packet_winpcap.c. Extra sleep of 50 ms
- * is added in to receive thread whenever no EAPOL frames has been received for
- * a while. Whenever an EAPOL handshake is expected, this sleep is removed.
- *
- * The RX thread receives a frame and signals main thread through Windows event
- * about the availability of a new frame. Processing the received frame is
- * synchronized with pair of Windows events so that no extra buffer or queuing
- * mechanism is needed. This implementation requires Windows specific event
- * loop implementation, i.e., eloop_win.c.
- *
- * WinPcap has pcap_getevent() that could, in theory at least, be used to
- * implement this kind of waiting with a simpler single-thread design. However,
- * that event handle is not really signaled immediately when receiving each
- * frame, so it does not really work for this kind of use.
- */
-
-#include "includes.h"
-#include <pcap.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 };
-
-/*
- * Number of pcap_dispatch() iterations to do without extra wait after each
- * received EAPOL packet or authentication notification. This is used to reduce
- * latency for EAPOL receive.
- */
-static const size_t no_wait_count = 750;
-
-struct l2_packet_data {
- pcap_t *pcap;
- unsigned int num_fast_poll;
- 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 and l2_packet_send() */
- int running;
- HANDLE rx_avail, rx_done, rx_thread, rx_thread_done, rx_notify;
- u8 *rx_buf, *rx_src;
- size_t rx_len;
- size_t rx_no_wait;
-};
-
-
-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;
- struct l2_ethhdr *eth;
-
- if (l2 == NULL)
- return -1;
-
- if (l2->l2_hdr) {
- ret = pcap_sendpacket(l2->pcap, buf, len);
- } 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);
- ret = pcap_sendpacket(l2->pcap, (u8 *) eth, mlen);
- os_free(eth);
- }
-
- return ret;
-}
-
-
-/* pcap_dispatch() callback for the RX thread */
-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;
-
- if (pkt_data == NULL || hdr->caplen < sizeof(*ethhdr))
- return;
-
- ethhdr = (struct l2_ethhdr *) pkt_data;
- if (l2->l2_hdr) {
- l2->rx_buf = (u8 *) ethhdr;
- l2->rx_len = hdr->caplen;
- } else {
- l2->rx_buf = (u8 *) (ethhdr + 1);
- l2->rx_len = hdr->caplen - sizeof(*ethhdr);
- }
- l2->rx_src = ethhdr->h_source;
- SetEvent(l2->rx_avail);
- WaitForSingleObject(l2->rx_done, INFINITE);
- ResetEvent(l2->rx_done);
- l2->rx_no_wait = no_wait_count;
-}
-
-
-/* main RX loop that is running in a separate thread */
-static DWORD WINAPI l2_packet_receive_thread(LPVOID arg)
-{
- struct l2_packet_data *l2 = arg;
-
- while (l2->running) {
- pcap_dispatch(l2->pcap, 1, l2_packet_receive_cb,
- (u_char *) l2);
- if (l2->rx_no_wait > 0)
- l2->rx_no_wait--;
- if (WaitForSingleObject(l2->rx_notify,
- l2->rx_no_wait ? 0 : 50) ==
- WAIT_OBJECT_0) {
- l2->rx_no_wait = no_wait_count;
- ResetEvent(l2->rx_notify);
- }
- }
- SetEvent(l2->rx_thread_done);
- ExitThread(0);
- return 0;
-}
-
-
-/* main thread RX event handler */
-static void l2_packet_rx_event(void *eloop_data, void *user_data)
-{
- struct l2_packet_data *l2 = eloop_data;
- l2->rx_callback(l2->rx_callback_ctx, l2->rx_src, l2->rx_buf,
- l2->rx_len);
- ResetEvent(l2->rx_avail);
- SetEvent(l2->rx_done);
-}
-
-
-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, 1, pcap_err);
- if (l2->pcap == NULL) {
- fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
- fprintf(stderr, "ifname='%s'\n", l2->ifname);
- 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);
-
- 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;
- DWORD thread_id;
-
- l2 = os_zalloc(sizeof(struct l2_packet_data));
- if (l2 == NULL)
- return NULL;
- if (os_strncmp(ifname, "\\Device\\NPF_", 12) == 0)
- os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
- else
- os_snprintf(l2->ifname, sizeof(l2->ifname), "\\Device\\NPF_%s",
- ifname);
- l2->rx_callback = rx_callback;
- l2->rx_callback_ctx = rx_callback_ctx;
- l2->l2_hdr = l2_hdr;
-
- if (own_addr)
- os_memcpy(l2->own_addr, own_addr, ETH_ALEN);
-
- if (l2_packet_init_libpcap(l2, protocol)) {
- os_free(l2);
- return NULL;
- }
-
- l2->rx_avail = CreateEvent(NULL, TRUE, FALSE, NULL);
- l2->rx_done = CreateEvent(NULL, TRUE, FALSE, NULL);
- l2->rx_notify = CreateEvent(NULL, TRUE, FALSE, NULL);
- if (l2->rx_avail == NULL || l2->rx_done == NULL ||
- l2->rx_notify == NULL) {
- CloseHandle(l2->rx_avail);
- CloseHandle(l2->rx_done);
- CloseHandle(l2->rx_notify);
- pcap_close(l2->pcap);
- os_free(l2);
- return NULL;
- }
-
- eloop_register_event(l2->rx_avail, sizeof(l2->rx_avail),
- l2_packet_rx_event, l2, NULL);
-
- l2->running = 1;
- l2->rx_thread = CreateThread(NULL, 0, l2_packet_receive_thread, l2, 0,
- &thread_id);
-
- return l2;
-}
-
-
-static void l2_packet_deinit_timeout(void *eloop_ctx, void *timeout_ctx)
-{
- struct l2_packet_data *l2 = eloop_ctx;
-
- if (l2->rx_thread_done &&
- WaitForSingleObject(l2->rx_thread_done, 2000) != WAIT_OBJECT_0) {
- wpa_printf(MSG_DEBUG, "l2_packet_winpcap: RX thread did not "
- "exit - kill it\n");
- TerminateThread(l2->rx_thread, 0);
- }
- CloseHandle(l2->rx_thread_done);
- CloseHandle(l2->rx_thread);
- if (l2->pcap)
- pcap_close(l2->pcap);
- eloop_unregister_event(l2->rx_avail, sizeof(l2->rx_avail));
- CloseHandle(l2->rx_avail);
- CloseHandle(l2->rx_done);
- CloseHandle(l2->rx_notify);
- os_free(l2);
-}
-
-
-void l2_packet_deinit(struct l2_packet_data *l2)
-{
- if (l2 == NULL)
- return;
-
- l2->rx_thread_done = CreateEvent(NULL, TRUE, FALSE, NULL);
-
- l2->running = 0;
- pcap_breakloop(l2->pcap);
-
- /*
- * RX thread may be waiting in l2_packet_receive_cb() for l2->rx_done
- * event and this event is set in l2_packet_rx_event(). However,
- * l2_packet_deinit() may end up being called from l2->rx_callback(),
- * so we need to return from here and complete deinitialization in
- * a registered timeout to avoid having to forcefully kill the RX
- * thread.
- */
- eloop_register_timeout(0, 0, l2_packet_deinit_timeout, l2, NULL);
-}
-
-
-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_strlcpy(buf, inet_ntoa(saddr->sin_addr),
- len);
- found = 1;
- break;
- }
- addr = addr->next;
- }
- }
-
- pcap_freealldevs(devs);
-
- return found ? 0 : -1;
-}
-
-
-void l2_packet_notify_auth_start(struct l2_packet_data *l2)
-{
- if (l2)
- SetEvent(l2->rx_notify);
-}
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