| /* |
| * WPA Supplicant - Layer2 packet handling with WinPcap RX thread |
| * Copyright (c) 2003-2006, Jouni Malinen <j@w1.fi> |
| * |
| * This software may be distributed under the terms of the BSD license. |
| * See README 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); |
| } |