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@@ -0,0 +1,402 @@
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+/**
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+ * @file BArpProbe.c
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+ * @author Ambroz Bizjak <ambrop7@gmail.com>
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+ *
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+ * @section LICENSE
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+ *
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+ * This file is part of BadVPN.
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+ *
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+ * BadVPN 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
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+ * as published by the Free Software Foundation.
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+ *
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+ * BadVPN is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License along
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+ * with this program; if not, write to the Free Software Foundation, Inc.,
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+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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+ */
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+
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+#include <stdio.h>
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+#include <string.h>
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+#include <unistd.h>
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+#include <sys/socket.h>
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+#include <net/if.h>
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+#include <net/if_arp.h>
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+#include <sys/ioctl.h>
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+#include <linux/filter.h>
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+
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+#include <misc/debug.h>
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+#include <misc/byteorder.h>
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+#include <misc/ethernet_proto.h>
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+#include <misc/ipv4_proto.h>
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+#include <misc/udp_proto.h>
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+#include <base/BLog.h>
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+
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+#include "BArpProbe.h"
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+
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+#include <generated/blog_channel_BArpProbe.h>
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+
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+#define STATE_INITIAL 1
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+#define STATE_NOEXIST 2
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+#define STATE_EXIST 3
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+#define STATE_EXIST_PANIC 4
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+
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+static int get_iface_info (const char *ifname, uint8_t *out_mac, int *out_mtu, int *out_ifindex)
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+{
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+ struct ifreq ifr;
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+
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+ int s = socket(AF_INET, SOCK_DGRAM, 0);
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+ if (!s) {
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+ BLog(BLOG_ERROR, "socket failed");
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+ goto fail0;
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+ }
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+
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+ // get MAC
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+ memset(&ifr, 0, sizeof(ifr));
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+ snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", ifname);
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+ if (ioctl(s, SIOCGIFHWADDR, &ifr)) {
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+ BLog(BLOG_ERROR, "ioctl(SIOCGIFHWADDR) failed");
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+ goto fail1;
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+ }
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+ if (ifr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
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+ BLog(BLOG_ERROR, "hardware address not ethernet");
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+ goto fail1;
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+ }
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+ memcpy(out_mac, ifr.ifr_hwaddr.sa_data, 6);
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+
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+ // get MTU
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+ memset(&ifr, 0, sizeof(ifr));
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+ snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", ifname);
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+ if (ioctl(s, SIOCGIFMTU, &ifr)) {
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+ BLog(BLOG_ERROR, "ioctl(SIOCGIFMTU) failed");
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+ goto fail1;
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+ }
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+ *out_mtu = ifr.ifr_mtu;
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+
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+ // get interface index
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+ memset(&ifr, 0, sizeof(ifr));
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+ snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", ifname);
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+ if (ioctl(s, SIOCGIFINDEX, &ifr)) {
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+ BLog(BLOG_ERROR, "ioctl(SIOCGIFINDEX) failed");
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+ goto fail1;
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+ }
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+ *out_ifindex = ifr.ifr_ifindex;
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+
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+ close(s);
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+
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+ return 1;
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+
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+fail1:
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+ close(s);
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+fail0:
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+ return 0;
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+}
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+
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+static void dgram_handler (BArpProbe *o, int event)
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+{
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+ DebugObject_Access(&o->d_obj);
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+
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+ BLog(BLOG_ERROR, "packet socket error");
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+
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+ // report error
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+ DEBUGERROR(&o->d_err, o->handler(o->user, BARPPROBE_EVENT_ERROR));
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+ return;
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+}
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+
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+static void send_request (BArpProbe *o)
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+{
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+ if (o->send_sending) {
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+ BLog(BLOG_ERROR, "cannot send packet while another packet is being sent!");
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+ return;
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+ }
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+
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+ // build packet
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+ struct arp_packet *arp = &o->send_packet;
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+ arp->hardware_type = hton16(ARP_HARDWARE_TYPE_ETHERNET);
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+ arp->protocol_type = hton16(ETHERTYPE_IPV4);
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+ arp->hardware_size = hton8(6);
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+ arp->protocol_size = hton8(4);
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+ arp->opcode = hton16(ARP_OPCODE_REQUEST);
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+ memcpy(arp->sender_mac, o->if_mac, 6);
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+ arp->sender_ip = hton32(0);
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+ memset(arp->target_mac, 0, sizeof(arp->target_mac));
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+ arp->target_ip = o->addr;
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+
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+ // send packet
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+ PacketPassInterface_Sender_Send(o->send_if, (uint8_t *)&o->send_packet, sizeof(o->send_packet));
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+
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+ // set sending
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+ o->send_sending = 1;
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+}
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+
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+static void send_if_handler_done (BArpProbe *o)
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+{
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+ DebugObject_Access(&o->d_obj);
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+ ASSERT(o->send_sending)
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+
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+ // set not sending
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+ o->send_sending = 0;
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+}
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+
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+static void recv_if_handler_done (BArpProbe *o, int data_len)
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+{
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+ DebugObject_Access(&o->d_obj);
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+ ASSERT(data_len >= 0)
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+ ASSERT(data_len <= sizeof(struct arp_packet))
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+
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+ // receive next packet
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+ PacketRecvInterface_Receiver_Recv(o->recv_if, (uint8_t *)&o->recv_packet);
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+
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+ if (data_len != sizeof(struct arp_packet)) {
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+ BLog(BLOG_WARNING, "receive: wrong size");
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+ return;
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+ }
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+
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+ struct arp_packet *arp = &o->recv_packet;
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+
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+ if (ntoh16(arp->hardware_type) != ARP_HARDWARE_TYPE_ETHERNET) {
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+ BLog(BLOG_WARNING, "receive: wrong hardware type");
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+ return;
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+ }
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+
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+ if (ntoh16(arp->protocol_type) != ETHERTYPE_IPV4) {
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+ BLog(BLOG_WARNING, "receive: wrong protocol type");
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+ return;
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+ }
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+
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+ if (ntoh8(arp->hardware_size) != 6) {
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+ BLog(BLOG_WARNING, "receive: wrong hardware size");
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+ return;
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+ }
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+
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+ if (ntoh8(arp->protocol_size) != 4) {
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+ BLog(BLOG_WARNING, "receive: wrong protocol size");
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+ return;
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+ }
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+
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+ if (ntoh16(arp->opcode) != ARP_OPCODE_REPLY) {
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+ return;
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+ }
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+
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+ if (arp->sender_ip != o->addr) {
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+ return;
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+ }
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+
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+ int old_state = o->state;
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+
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+ // set minus one missed
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+ o->num_missed = -1;
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+
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_WAITSEND);
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+
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+ // set state exist
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+ o->state = STATE_EXIST;
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+
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+ // report exist if needed
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+ if (old_state == STATE_INITIAL || old_state == STATE_NOEXIST) {
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+ o->handler(o->user, BARPPROBE_EVENT_EXIST);
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+ return;
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+ }
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+}
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+
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+static void timer_handler (BArpProbe *o)
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+{
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+ DebugObject_Access(&o->d_obj);
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+
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+ // send request
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+ send_request(o);
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+
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+ switch (o->state) {
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+ case STATE_INITIAL: {
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+ ASSERT(o->num_missed >= 0)
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+ ASSERT(o->num_missed < BARPPROBE_INITIAL_NUM_ATTEMPTS)
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+
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+ // increment missed
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+ o->num_missed++;
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+
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+ // all attempts failed?
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+ if (o->num_missed == BARPPROBE_INITIAL_NUM_ATTEMPTS) {
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV);
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+
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+ // set state noexist
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+ o->state = STATE_NOEXIST;
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+
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+ // report noexist
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+ o->handler(o->user, BARPPROBE_EVENT_NOEXIST);
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+ return;
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+ }
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+
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_INITIAL_WAITRECV);
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+ } break;
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+
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+ case STATE_NOEXIST: {
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV);
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+ } break;
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+
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+ case STATE_EXIST: {
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+ ASSERT(o->num_missed >= -1)
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+ ASSERT(o->num_missed < BARPPROBE_EXIST_NUM_NOREPLY)
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+
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+ // increment missed
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+ o->num_missed++;
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+
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+ // all missed?
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+ if (o->num_missed == BARPPROBE_EXIST_NUM_NOREPLY) {
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_PANIC_WAITRECV);
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+
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+ // set zero missed
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+ o->num_missed = 0;
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+
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+ // set state panic
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+ o->state = STATE_EXIST_PANIC;
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+ return;
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+ }
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+
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_WAITRECV);
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+ } break;
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+
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+ case STATE_EXIST_PANIC: {
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+ ASSERT(o->num_missed >= 0)
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+ ASSERT(o->num_missed < BARPPROBE_EXIST_PANIC_NUM_NOREPLY)
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+
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+ // increment missed
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+ o->num_missed++;
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+
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+ // all missed?
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+ if (o->num_missed == BARPPROBE_EXIST_PANIC_NUM_NOREPLY) {
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV);
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+
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+ // set state panic
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+ o->state = STATE_NOEXIST;
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+
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+ // report noexist
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+ o->handler(o->user, BARPPROBE_EVENT_NOEXIST);
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+ return;
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+ }
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+
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_PANIC_WAITRECV);
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+ } break;
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+ }
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+}
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+
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+int BArpProbe_Init (BArpProbe *o, const char *ifname, uint32_t addr, BReactor *reactor, void *user, BArpProbe_handler handler)
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+{
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+ ASSERT(ifname)
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+ ASSERT(handler)
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+
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+ // init arguments
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+ o->addr = addr;
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+ o->reactor = reactor;
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+ o->user = user;
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+ o->handler = handler;
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+
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+ // get interface information
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+ int if_mtu;
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+ int if_index;
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+ if (!get_iface_info(ifname, o->if_mac, &if_mtu, &if_index)) {
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+ BLog(BLOG_ERROR, "failed to get interface information");
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+ goto fail0;
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+ }
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+
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+ uint8_t *if_mac = o->if_mac;
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+ BLog(BLOG_INFO, "if_mac=%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8" if_mtu=%d if_index=%d",
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+ if_mac[0], if_mac[1], if_mac[2], if_mac[3], if_mac[4], if_mac[5], if_mtu, if_index);
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+
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+ // check MTU
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+ if (if_mtu < sizeof(struct arp_packet)) {
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+ BLog(BLOG_ERROR, "MTU is too small for ARP !?!");
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+ goto fail0;
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+ }
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+
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+ // init dgram
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+ if (!BDatagram_Init(&o->dgram, BADDR_TYPE_PACKET, o->reactor, o, (BDatagram_handler)dgram_handler)) {
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+ BLog(BLOG_ERROR, "BDatagram_Init failed");
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+ goto fail0;
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+ }
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+
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+ // bind dgram
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+ BAddr bind_addr;
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+ BAddr_InitPacket(&bind_addr, hton16(ETHERTYPE_ARP), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_HOST, if_mac);
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+ if (!BDatagram_Bind(&o->dgram, bind_addr)) {
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+ BLog(BLOG_ERROR, "BDatagram_Bind failed");
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+ goto fail1;
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+ }
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+
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+ // set dgram send addresses
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+ BAddr dest_addr;
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+ uint8_t broadcast_mac[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
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+ BAddr_InitPacket(&dest_addr, hton16(ETHERTYPE_ARP), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_BROADCAST, broadcast_mac);
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+ BIPAddr local_addr;
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+ BIPAddr_InitInvalid(&local_addr);
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+ BDatagram_SetSendAddrs(&o->dgram, dest_addr, local_addr);
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+
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+ // init send interface
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+ BDatagram_SendAsync_Init(&o->dgram, sizeof(struct arp_packet));
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+ o->send_if = BDatagram_SendAsync_GetIf(&o->dgram);
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+ PacketPassInterface_Sender_Init(o->send_if, (PacketPassInterface_handler_done)send_if_handler_done, o);
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+
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+ // set not sending
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+ o->send_sending = 0;
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+
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+ // init recv interface
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+ BDatagram_RecvAsync_Init(&o->dgram, sizeof(struct arp_packet));
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+ o->recv_if = BDatagram_RecvAsync_GetIf(&o->dgram);
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+ PacketRecvInterface_Receiver_Init(o->recv_if, (PacketRecvInterface_handler_done)recv_if_handler_done, o);
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+
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+ // init timer
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+ BTimer_Init(&o->timer, 0, (BTimer_handler)timer_handler, o);
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+
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+ // receive first packet
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+ PacketRecvInterface_Receiver_Recv(o->recv_if, (uint8_t *)&o->recv_packet);
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+
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+ // send request
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+ send_request(o);
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+
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+ // set timer
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+ BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_INITIAL_WAITRECV);
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+
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+ // set zero missed
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+ o->num_missed = 0;
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+
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+ // set state initial
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+ o->state = STATE_INITIAL;
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+
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+ DebugError_Init(&o->d_err, BReactor_PendingGroup(o->reactor));
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+ DebugObject_Init(&o->d_obj);
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+ return 1;
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+
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+fail1:
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+ BDatagram_Free(&o->dgram);
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+fail0:
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+ return 0;
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+}
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+
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+void BArpProbe_Free (BArpProbe *o)
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+{
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+ DebugObject_Free(&o->d_obj);
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+ DebugError_Free(&o->d_err);
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+
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+ // free timer
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+ BReactor_RemoveTimer(o->reactor, &o->timer);
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+
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+ // free recv interface
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+ BDatagram_RecvAsync_Free(&o->dgram);
|
|
|
+
|
|
|
+ // free send interface
|
|
|
+ BDatagram_SendAsync_Free(&o->dgram);
|
|
|
+
|
|
|
+ // free dgram
|
|
|
+ BDatagram_Free(&o->dgram);
|
|
|
+}
|
ambrop7