gdhcp: Add IPv4 Link-Local support
authorJulien Massot <jmassot@aldebaran-robotics.com>
Fri, 10 Dec 2010 11:00:33 +0000 (11:00 +0000)
committerSamuel Ortiz <sameo@linux.intel.com>
Tue, 14 Dec 2010 00:42:31 +0000 (01:42 +0100)
IPv4 Link-Local negociation starts on gdhcp client failure.

Makefile.am
gdhcp/client.c
gdhcp/gdhcp.h
gdhcp/ipv4ll.c [new file with mode: 0644]
gdhcp/ipv4ll.h [new file with mode: 0644]

index 444c48a..08260c2 100644 (file)
@@ -27,7 +27,7 @@ gdbus_sources = gdbus/gdbus.h gdbus/mainloop.c gdbus/watch.c \
                                        gdbus/object.c gdbus/polkit.c
 
 gdhcp_sources = gdhcp/gdhcp.h gdhcp/common.h gdhcp/common.c gdhcp/client.c \
-               gdhcp/server.c
+               gdhcp/server.c gdhcp/ipv4ll.h gdhcp/ipv4ll.c
 
 gweb_sources = gweb/gweb.h gweb/gweb.c gweb/gresolv.h gweb/gresolv.c \
                                        gweb/giognutls.h gweb/giognutls.c
index 12d927e..3508b1e 100644 (file)
@@ -32,6 +32,7 @@
 #include <arpa/inet.h>
 
 #include <netpacket/packet.h>
+#include <netinet/if_ether.h>
 #include <net/ethernet.h>
 
 #include <linux/if.h>
@@ -41,6 +42,7 @@
 
 #include "gdhcp.h"
 #include "common.h"
+#include "ipv4ll.h"
 
 #define DISCOVER_TIMEOUT 3
 #define DISCOVER_RETRIES 10
@@ -52,6 +54,7 @@ typedef enum _listen_mode {
        L_NONE,
        L2,
        L3,
+       L_ARP,
 } ListenMode;
 
 typedef enum _dhcp_client_state {
@@ -61,6 +64,10 @@ typedef enum _dhcp_client_state {
        RENEWING,
        REBINDING,
        RELEASED,
+       IPV4LL_PROBE,
+       IPV4LL_ANNOUNCE,
+       IPV4LL_MONITOR,
+       IPV4LL_DEFEND,
 } ClientState;
 
 struct _GDHCPClient {
@@ -79,6 +86,7 @@ struct _GDHCPClient {
        int listener_sockfd;
        uint8_t retry_times;
        uint8_t ack_retry_times;
+       uint8_t conflicts;
        guint timeout;
        guint listener_watch;
        GIOChannel *listener_channel;
@@ -88,10 +96,14 @@ struct _GDHCPClient {
        GHashTable *send_value_hash;
        GDHCPClientEventFunc lease_available_cb;
        gpointer lease_available_data;
+       GDHCPClientEventFunc ipv4ll_available_cb;
+       gpointer ipv4ll_available_data;
        GDHCPClientEventFunc no_lease_cb;
        gpointer no_lease_data;
        GDHCPClientEventFunc lease_lost_cb;
        gpointer lease_lost_data;
+       GDHCPClientEventFunc ipv4ll_lost_cb;
+       gpointer ipv4ll_lost_data;
        GDHCPClientEventFunc address_conflict_cb;
        gpointer address_conflict_data;
        GDHCPDebugFunc debug_func;
@@ -267,7 +279,83 @@ static int send_release(GDHCPClient *dhcp_client,
                                                server, SERVER_PORT);
 }
 
+static gboolean ipv4ll_probe_timeout(gpointer dhcp_data);
+static int switch_listening_mode(GDHCPClient *dhcp_client,
+                                       ListenMode listen_mode);
+
+static gboolean send_probe_packet(gpointer dhcp_data)
+{
+       GDHCPClient *dhcp_client;
+       guint timeout;
+
+       dhcp_client = dhcp_data;
+       /* if requested_ip is not valid, pick a new address*/
+       if (dhcp_client->requested_ip == 0) {
+               debug(dhcp_client, "pick a new random address");
+               dhcp_client->requested_ip = ipv4ll_random_ip(0);
+       }
+
+       debug(dhcp_client, "sending IPV4LL probe request");
+
+       if (dhcp_client->retry_times == 1) {
+               dhcp_client->state = IPV4LL_PROBE;
+               switch_listening_mode(dhcp_client, L_ARP);
+       }
+       ipv4ll_send_arp_packet(dhcp_client->mac_address, 0,
+                       dhcp_client->requested_ip, dhcp_client->ifindex);
+
+       if (dhcp_client->retry_times < PROBE_NUM) {
+               /*add a random timeout in range of PROBE_MIN to PROBE_MAX*/
+               timeout = ipv4ll_random_delay_ms(PROBE_MAX-PROBE_MIN);
+               timeout += PROBE_MIN*1000;
+       } else
+               timeout = (ANNOUNCE_WAIT * 1000);
+
+       dhcp_client->timeout = g_timeout_add_full(G_PRIORITY_HIGH,
+                                                timeout,
+                                                ipv4ll_probe_timeout,
+                                                dhcp_client,
+                                                NULL);
+       return FALSE;
+}
+
+static gboolean ipv4ll_announce_timeout(gpointer dhcp_data);
+static gboolean ipv4ll_defend_timeout(gpointer dhcp_data);
+
+static gboolean send_announce_packet(gpointer dhcp_data)
+{
+       GDHCPClient *dhcp_client;
 
+       dhcp_client = dhcp_data;
+
+       debug(dhcp_client, "sending IPV4LL announce request");
+
+       ipv4ll_send_arp_packet(dhcp_client->mac_address,
+                               dhcp_client->requested_ip,
+                               dhcp_client->requested_ip,
+                               dhcp_client->ifindex);
+
+       if (dhcp_client->timeout > 0)
+               g_source_remove(dhcp_client->timeout);
+       dhcp_client->timeout = 0;
+
+       if (dhcp_client->state == IPV4LL_DEFEND) {
+               dhcp_client->timeout =
+                       g_timeout_add_seconds_full(G_PRIORITY_HIGH,
+                                               DEFEND_INTERVAL,
+                                               ipv4ll_defend_timeout,
+                                               dhcp_client,
+                                               NULL);
+               return TRUE;
+       } else
+               dhcp_client->timeout =
+                       g_timeout_add_seconds_full(G_PRIORITY_HIGH,
+                                               ANNOUNCE_INTERVAL,
+                                               ipv4ll_announce_timeout,
+                                               dhcp_client,
+                                               NULL);
+       return TRUE;
+}
 
 static void get_interface_mac_address(int index, uint8_t *mac_address)
 {
@@ -350,8 +438,10 @@ GDHCPClient *g_dhcp_client_new(GDHCPType type,
        dhcp_client->type = type;
        dhcp_client->ifindex = ifindex;
        dhcp_client->lease_available_cb = NULL;
+       dhcp_client->ipv4ll_available_cb = NULL;
        dhcp_client->no_lease_cb = NULL;
        dhcp_client->lease_lost_cb = NULL;
+       dhcp_client->ipv4ll_lost_cb = NULL;
        dhcp_client->address_conflict_cb = NULL;
        dhcp_client->listener_watch = 0;
        dhcp_client->retry_times = 0;
@@ -516,6 +606,131 @@ static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd)
        return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
 }
 
+static void ipv4ll_start(GDHCPClient *dhcp_client)
+{
+       guint timeout;
+       int seed;
+
+       if (dhcp_client->timeout > 0) {
+               g_source_remove(dhcp_client->timeout);
+               dhcp_client->timeout = 0;
+       }
+
+       switch_listening_mode(dhcp_client, L_NONE);
+       dhcp_client->type = G_DHCP_IPV4LL;
+       dhcp_client->retry_times = 0;
+       dhcp_client->requested_ip = 0;
+
+       /*try to start with a based mac address ip*/
+       seed = (dhcp_client->mac_address[4] << 8 | dhcp_client->mac_address[4]);
+       dhcp_client->requested_ip = ipv4ll_random_ip(seed);
+
+       /*first wait a random delay to avoid storm of arp request on boot*/
+       timeout = ipv4ll_random_delay_ms(PROBE_WAIT);
+
+       dhcp_client->retry_times++;
+       dhcp_client->timeout = g_timeout_add_full(G_PRIORITY_HIGH,
+                                               timeout,
+                                               send_probe_packet,
+                                               dhcp_client,
+                                               NULL);
+}
+
+static void ipv4ll_stop(GDHCPClient *dhcp_client)
+{
+
+       switch_listening_mode(dhcp_client, L_NONE);
+
+       if (dhcp_client->timeout > 0)
+               g_source_remove(dhcp_client->timeout);
+
+       if (dhcp_client->listener_watch > 0) {
+               g_source_remove(dhcp_client->listener_watch);
+               dhcp_client->listener_watch = 0;
+       }
+
+       dhcp_client->state = IPV4LL_PROBE;
+       dhcp_client->retry_times = 0;
+       dhcp_client->requested_ip = 0;
+
+       g_free(dhcp_client->assigned_ip);
+       dhcp_client->assigned_ip = NULL;
+}
+
+static int ipv4ll_recv_arp_packet(GDHCPClient *dhcp_client)
+{
+       int bytes;
+       struct ether_arp arp;
+       uint32_t ip_requested;
+       int source_conflict;
+       int target_conflict;
+
+       memset(&arp, 0, sizeof(arp));
+       bytes = 0;
+       bytes = read(dhcp_client->listener_sockfd, &arp, sizeof(arp));
+       if (bytes < 0)
+               return bytes;
+
+       if (arp.arp_op != htons(ARPOP_REPLY) &&
+                       arp.arp_op != htons(ARPOP_REQUEST))
+               return -EINVAL;
+
+       ip_requested = ntohl(dhcp_client->requested_ip);
+       source_conflict = !memcmp(arp.arp_spa, &ip_requested,
+                                               sizeof(ip_requested));
+
+       target_conflict = !memcmp(arp.arp_tpa, &ip_requested,
+                               sizeof(ip_requested));
+
+       if (!source_conflict && !target_conflict)
+               return 0;
+
+       dhcp_client->conflicts++;
+
+       debug(dhcp_client, "IPV4LL conflict detected");
+
+       if (dhcp_client->state == IPV4LL_MONITOR) {
+               if (!source_conflict)
+                       return 0;
+               dhcp_client->state = IPV4LL_DEFEND;
+               debug(dhcp_client, "DEFEND mode conflicts : %d",
+                       dhcp_client->conflicts);
+               /*Try to defend with a single announce*/
+               send_announce_packet(dhcp_client);
+               return 0;
+       }
+
+       if (dhcp_client->state == IPV4LL_DEFEND) {
+               if (!source_conflict)
+                       return 0;
+               else if (dhcp_client->ipv4ll_lost_cb != NULL)
+                       dhcp_client->ipv4ll_lost_cb(dhcp_client,
+                                               dhcp_client->ipv4ll_lost_data);
+       }
+
+       ipv4ll_stop(dhcp_client);
+
+       if (dhcp_client->conflicts < MAX_CONFLICTS) {
+               /*restart whole state machine*/
+               dhcp_client->retry_times++;
+               dhcp_client->timeout =
+                       g_timeout_add_full(G_PRIORITY_HIGH,
+                                       ipv4ll_random_delay_ms(PROBE_WAIT),
+                                       send_probe_packet,
+                                       dhcp_client,
+                                       NULL);
+       }
+       /* Here we got a lot of conflicts, RFC3927 states that we have
+        * to wait RATE_LIMIT_INTERVAL before retrying,
+        * but we just report failure.
+        */
+       else if (dhcp_client->no_lease_cb != NULL)
+                       dhcp_client->no_lease_cb(dhcp_client,
+                                               dhcp_client->no_lease_data);
+
+       return 0;
+}
+
 static gboolean check_package_owner(GDHCPClient *dhcp_client,
                                        struct dhcp_packet *packet)
 {
@@ -578,6 +793,8 @@ static int switch_listening_mode(GDHCPClient *dhcp_client,
        else if (listen_mode == L3)
                listener_sockfd = dhcp_l3_socket(CLIENT_PORT,
                                                dhcp_client->interface);
+       else if (listen_mode == L_ARP)
+               listener_sockfd = ipv4ll_arp_socket(dhcp_client->ifindex);
        else
                return -EIO;
 
@@ -613,10 +830,7 @@ static void start_request(GDHCPClient *dhcp_client)
 
        if (dhcp_client->retry_times == REQUEST_RETRIES) {
                dhcp_client->state = INIT_SELECTING;
-
-               if (dhcp_client->no_lease_cb != NULL)
-                       dhcp_client->no_lease_cb(dhcp_client,
-                                       dhcp_client->no_lease_data);
+               ipv4ll_start(dhcp_client);
 
                return;
        }
@@ -927,6 +1141,10 @@ static gboolean listener_event(GIOChannel *channel, GIOCondition condition,
                re = dhcp_recv_l2_packet(&packet, dhcp_client->listener_sockfd);
        else if (dhcp_client->listen_mode == L3)
                re = dhcp_recv_l3_packet(&packet, dhcp_client->listener_sockfd);
+       else if (dhcp_client->listen_mode == L_ARP) {
+               re = ipv4ll_recv_arp_packet(dhcp_client);
+               return TRUE;
+       }
        else
                re = -EIO;
 
@@ -1023,15 +1241,73 @@ static gboolean discover_timeout(gpointer user_data)
        return FALSE;
 }
 
+static gboolean ipv4ll_defend_timeout(gpointer dhcp_data)
+{
+       GDHCPClient *dhcp_client = dhcp_data;
+
+       debug(dhcp_client, "back to MONITOR mode");
+
+       dhcp_client->conflicts = 0;
+       dhcp_client->state = IPV4LL_MONITOR;
+
+       return FALSE;
+}
+
+static gboolean ipv4ll_announce_timeout(gpointer dhcp_data)
+{
+       GDHCPClient *dhcp_client = dhcp_data;
+       uint32_t ip;
+
+       debug(dhcp_client, "request timeout (retries %d)",
+              dhcp_client->retry_times);
+
+       if (dhcp_client->retry_times != ANNOUNCE_NUM){
+               dhcp_client->retry_times++;
+               send_announce_packet(dhcp_client);
+               return FALSE;
+       }
+
+       ip = htonl(dhcp_client->requested_ip);
+       debug(dhcp_client, "switching to monitor mode");
+       dhcp_client->state = IPV4LL_MONITOR;
+       dhcp_client->assigned_ip = get_ip(ip);
+
+       if (dhcp_client->ipv4ll_available_cb != NULL)
+               dhcp_client->ipv4ll_available_cb(dhcp_client,
+                                       dhcp_client->ipv4ll_available_data);
+       dhcp_client->conflicts = 0;
+
+       return FALSE;
+}
+
+static gboolean ipv4ll_probe_timeout(gpointer dhcp_data)
+{
+
+       GDHCPClient *dhcp_client = dhcp_data;
+
+       debug(dhcp_client, "IPV4LL probe timeout (retries %d)",
+              dhcp_client->retry_times);
+
+       if (dhcp_client->retry_times == PROBE_NUM) {
+               dhcp_client->state = IPV4LL_ANNOUNCE;
+               dhcp_client->retry_times = 0;
+
+               dhcp_client->retry_times++;
+               send_announce_packet(dhcp_client);
+               return FALSE;
+       }
+       dhcp_client->retry_times++;
+       send_probe_packet(dhcp_client);
+
+       return FALSE;
+}
+
 int g_dhcp_client_start(GDHCPClient *dhcp_client)
 {
        int re;
 
        if (dhcp_client->retry_times == DISCOVER_RETRIES) {
-               if (dhcp_client->no_lease_cb != NULL)
-                       dhcp_client->no_lease_cb(dhcp_client,
-                                       dhcp_client->no_lease_data);
-
+               ipv4ll_start(dhcp_client);
                return 0;
        }
 
@@ -1104,6 +1380,10 @@ void g_dhcp_client_register_event(GDHCPClient *dhcp_client,
                dhcp_client->lease_available_cb = func;
                dhcp_client->lease_available_data = data;
                return;
+       case G_DHCP_CLIENT_EVENT_IPV4LL_AVAILABLE:
+               dhcp_client->ipv4ll_available_cb = func;
+               dhcp_client->ipv4ll_available_data = data;
+               return;
        case G_DHCP_CLIENT_EVENT_NO_LEASE:
                dhcp_client->no_lease_cb = func;
                dhcp_client->no_lease_data = data;
@@ -1112,6 +1392,10 @@ void g_dhcp_client_register_event(GDHCPClient *dhcp_client,
                dhcp_client->lease_lost_cb = func;
                dhcp_client->lease_lost_data = data;
                return;
+       case G_DHCP_CLIENT_EVENT_IPV4LL_LOST:
+               dhcp_client->ipv4ll_lost_cb = func;
+               dhcp_client->ipv4ll_lost_data = data;
+               return;
        case G_DHCP_CLIENT_EVENT_ADDRESS_CONFLICT:
                dhcp_client->address_conflict_cb = func;
                dhcp_client->address_conflict_data = data;
index 052ab90..63c395d 100644 (file)
@@ -45,14 +45,17 @@ typedef enum {
 
 typedef enum {
        G_DHCP_CLIENT_EVENT_LEASE_AVAILABLE,
+       G_DHCP_CLIENT_EVENT_IPV4LL_AVAILABLE,
        G_DHCP_CLIENT_EVENT_NO_LEASE,
        G_DHCP_CLIENT_EVENT_LEASE_LOST,
+       G_DHCP_CLIENT_EVENT_IPV4LL_LOST,
        G_DHCP_CLIENT_EVENT_ADDRESS_CONFLICT,
 } GDHCPClientEvent;
 
 typedef enum {
        G_DHCP_IPV4,
        G_DHCP_IPV6,
+       G_DHCP_IPV4LL,
 } GDHCPType;
 
 #define G_DHCP_SUBNET          0x01
diff --git a/gdhcp/ipv4ll.c b/gdhcp/ipv4ll.c
new file mode 100644 (file)
index 0000000..b35626d
--- /dev/null
@@ -0,0 +1,139 @@
+/*
+ *
+ *  IPV4 Local Link library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Aldebaran Robotics. All rights reserved.
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netpacket/packet.h>
+#include <net/ethernet.h>
+#include <netinet/if_ether.h>
+
+#include <arpa/inet.h>
+
+#include <glib.h>
+#include "ipv4ll.h"
+
+/**
+ * Return a random link local IP
+ */
+uint32_t ipv4ll_random_ip(int seed)
+{
+       unsigned tmp;
+
+       if (seed)
+               srand(seed);
+       else {
+               struct timeval tv;
+               gettimeofday(&tv, NULL);
+               srand(tv.tv_usec);
+       }
+       do {
+               tmp = rand();
+               tmp = tmp & IN_CLASSB_HOST;
+       } while (tmp > (IN_CLASSB_HOST - 0x0200));
+       return ((LINKLOCAL_ADDR + 0x0100) + tmp);
+}
+
+/**
+ * Return a random delay in range of zero to secs*1000
+ */
+guint ipv4ll_random_delay_ms(guint secs)
+{
+       struct timeval tv;
+       guint tmp;
+
+       gettimeofday(&tv, NULL);
+       srand(tv.tv_usec);
+       tmp = rand();
+       return tmp % (secs * 1000);
+}
+
+int ipv4ll_send_arp_packet(uint8_t* source_eth, uint32_t source_ip,
+                   uint32_t target_ip, int ifindex)
+{
+       struct sockaddr_ll dest;
+       struct ether_arp p;
+       uint32_t ip_source;
+       uint32_t ip_target;
+       int fd, n;
+
+       fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ARP));
+       if (fd < 0)
+               return -errno;
+
+       memset(&dest, 0, sizeof(dest));
+       memset(&p, 0, sizeof(p));
+
+       dest.sll_family = AF_PACKET;
+       dest.sll_protocol = htons(ETH_P_ARP);
+       dest.sll_ifindex = ifindex;
+       dest.sll_halen = ETH_ALEN;
+       memset(dest.sll_addr, 0xFF, ETH_ALEN);
+       if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
+               close(fd);
+               return -errno;
+       }
+
+       ip_source = htonl(source_ip);
+       ip_target = htonl(target_ip);
+       p.arp_hrd = htons(ARPHRD_ETHER);
+       p.arp_pro = htons(ETHERTYPE_IP);
+       p.arp_hln = ETH_ALEN;
+       p.arp_pln = 4;
+       p.arp_op = htons(ARPOP_REQUEST);
+
+       memcpy(&p.arp_sha, source_eth, ETH_ALEN);
+       memcpy(&p.arp_spa, &ip_source, sizeof(p.arp_spa));
+       memcpy(&p.arp_tpa, &ip_target, sizeof(p.arp_tpa));
+
+       n = sendto(fd, &p, sizeof(p), 0,
+              (struct sockaddr*) &dest, sizeof(dest));
+       if (n < 0)
+               return -errno;
+
+       close(fd);
+
+       return n;
+}
+
+int ipv4ll_arp_socket(int ifindex)
+{
+       int fd;
+       struct sockaddr_ll sock;
+       fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ARP));
+       if (fd < 0)
+               return fd;
+
+       sock.sll_family = AF_PACKET;
+       sock.sll_protocol = htons(ETH_P_ARP);
+       sock.sll_ifindex = ifindex;
+
+       if (bind(fd, (struct sockaddr *) &sock, sizeof(sock)) != 0) {
+               close(fd);
+               return -errno;
+       }
+
+       return fd;
+}
diff --git a/gdhcp/ipv4ll.h b/gdhcp/ipv4ll.h
new file mode 100644 (file)
index 0000000..aaac33e
--- /dev/null
@@ -0,0 +1,55 @@
+/*
+ *
+ *  IPV4 Local Link library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Aldebaran Robotics. All rights reserved.
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __G_IPV4LL_H
+#define __G_IPV4LL_H
+
+#include <glib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* 169.254.0.0 */
+#define LINKLOCAL_ADDR 0xa9fe0000
+
+/* See RFC 3927 */
+#define PROBE_WAIT          1
+#define PROBE_NUM           3
+#define PROBE_MIN           1
+#define PROBE_MAX           2
+#define ANNOUNCE_WAIT       2
+#define ANNOUNCE_NUM        2
+#define ANNOUNCE_INTERVAL    2
+#define MAX_CONFLICTS      10
+#define RATE_LIMIT_INTERVAL 60
+#define DEFEND_INTERVAL            10
+
+uint32_t ipv4ll_random_ip(int seed);
+guint ipv4ll_random_delay_ms(guint secs);
+int ipv4ll_send_arp_packet(uint8_t* source_eth, uint32_t source_ip,
+                   uint32_t target_ip, int ifindex);
+int ipv4ll_arp_socket(int ifindex);
+
+#ifdef __cplusplus
+}
+#endif
+#endif     /* !IPV4LL_H_ */