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/*
* Copyright (c) 2007, Sven-Ola Tuecke <sven-ola-aet-gmx.de>
* Copyright (c) 2004, Andreas Tonnesen(andreto-at-olsr.org)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the UniK olsr daemon nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/*
* Plugin to refresh the local ARP cache from received OLSR broadcasts
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_arp.h>
#ifndef android
#include <net/ethernet.h>
#endif
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netpacket/packet.h>
#include <linux/types.h>
#include <linux/filter.h>
#include <unistd.h>
#include "olsrd_arprefresh.h"
#include "kernel_routes.h"
#include "scheduler.h"
#undef ARPREFRESH_DEBUG
#define PLUGIN_INTERFACE_VERSION 5
/****************************************************************************
* Functions that the plugin MUST provide *
****************************************************************************/
/**
* Plugin interface version
* Used by main olsrd to check plugin interface version
*/
int
olsrd_plugin_interface_version(void)
{
return PLUGIN_INTERFACE_VERSION;
}
static const struct olsrd_plugin_parameters plugin_parameters[] = {
};
void
olsrd_get_plugin_parameters(const struct olsrd_plugin_parameters **params, int *size)
{
*params = plugin_parameters;
*size = sizeof(plugin_parameters) / sizeof(*plugin_parameters);
}
typedef struct {
struct ethhdr eth;
struct iphdr ip;
struct udphdr udp;
} __attribute__ ((packed)) arprefresh_buf;
static int arprefresh_sockfd = -1;
static const int arprefresh_portnum = 698;
/**
* Scheduled event to fetch gathered packets and update the ARP cache
* called from olsrd main thread
*/
static void
olsr_arp_event(void *foo __attribute__ ((unused)))
{
if (0 <= arprefresh_sockfd) {
arprefresh_buf buf;
struct sockaddr_ll from;
socklen_t fromlen = sizeof(from);
/*
* Grab a single snapshot on the packet socket. This only works
* if not too much IP traffic is currently flowing through.
*/
ssize_t size = recvfrom(arprefresh_sockfd, &buf, sizeof(buf),
MSG_TRUNC, (struct sockaddr *)&from,
&fromlen);
if (0 <= size && size >= (ssize_t) sizeof(buf)
/*** &&
ETH_P_IP == ntohs(buf.eth.h_proto) &&
IPPROTO_UDP == buf.ip.protocol &&
arprefresh_portnum == ntohs(buf.udp.source) &&
arprefresh_portnum == ntohs(buf.udp.dest) ***/
) {
union {
struct arpreq arp;
struct sockaddr_in in_pa;
struct sockaddr_in6 in_pa6;
} req;
memset(&req, 0, sizeof(req));
req.in_pa.sin_family = AF_INET;
memcpy(&req.in_pa.sin_addr, &buf.ip.saddr, sizeof(buf.ip.saddr));
req.arp.arp_ha.sa_family = AF_LOCAL;
memcpy(&req.arp.arp_ha.sa_data, &buf.eth.h_source, sizeof(buf.eth.h_source));
req.arp.arp_flags = ATF_COM;
if_indextoname(from.sll_ifindex, req.arp.arp_dev);
#ifdef ARPREFRESH_DEBUG
{
int i;
OLSR_PRINTF(0, "Refresh on %s, %s=", req.arp.arp_dev, inet_ntoa(*((struct in_addr *)&buf.ip.saddr)));
for (i = 0; i < (ssize_t) sizeof(buf.eth.h_source); i++) {
OLSR_PRINTF(0, "%02x%s", ((unsigned char *)&buf.eth.h_source)[i],
i < (ssize_t) sizeof(buf.eth.h_source) - 1 ? ":" : "\n");
}
}
#endif
if (ioctl(arprefresh_sockfd, SIOCSARP, &req) < 0) {
OLSR_PRINTF(1, "*** ARPREFRESH: SIOCSARP: %s\n", strerror(errno));
close(arprefresh_sockfd);
arprefresh_sockfd = -1;
return;
}
}
}
}
/**
* Initialize plugin
* Called after all parameters are passed
*/
int
olsrd_plugin_init(void)
{
int ret = 0;
if (AF_INET == olsr_cnf->ip_version) {
int flags;
struct sock_fprog filter;
struct sock_filter BPF_code[] = {
/* tcpdump -s [sizeof(arprefresh_buf)] -ni lo udp and dst port [arprefresh_portnum] -dd */
{0x28, 0, 0, 0x0000000c},
{0x15, 0, 4, 0x000086dd},
{0x30, 0, 0, 0x00000014},
{0x15, 0, 11, 0x00000011},
{0x28, 0, 0, 0x00000038},
{0x15, 8, 9, arprefresh_portnum},
{0x15, 0, 8, 0x00000800},
{0x30, 0, 0, 0x00000017},
{0x15, 0, 6, 0x00000011},
{0x28, 0, 0, 0x00000014},
{0x45, 4, 0, 0x00001fff},
{0xb1, 0, 0, 0x0000000e},
{0x48, 0, 0, 0x00000010},
{0x15, 0, 1, arprefresh_portnum},
{0x6, 0, 0, sizeof(arprefresh_buf)}
,
{0x6, 0, 0, 0x00000000}
};
filter.len = sizeof(BPF_code) / sizeof(BPF_code[0]);
filter.filter = BPF_code;
if (0 <= (arprefresh_sockfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP)))
&& 0 <= (flags = fcntl(arprefresh_sockfd, F_GETFL))
&& 0 <= fcntl(arprefresh_sockfd, F_SETFL, flags | O_NONBLOCK)
&& 0 <= setsockopt(arprefresh_sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter))) {
/* Register the ARP refresh event */
olsr_start_timer(2 * MSEC_PER_SEC, 0, OLSR_TIMER_PERIODIC, &olsr_arp_event, NULL, 0);
ret = 1;
} else {
OLSR_PRINTF(1, "*** ARPREFRESH: Cannot create non-blocking filtering packet socket: %s\n", strerror(errno));
}
} else {
OLSR_PRINTF(1, "*** ARPREFRESH: IPv6 not supported\n");
}
return ret;
}
/****************************************************************************
* Optional private constructor and destructor functions *
****************************************************************************/
static void __attribute__ ((constructor)) my_init(void);
static void __attribute__ ((destructor)) my_fini(void);
static void
my_init(void)
{
printf("OLSRD arprefresh plugin by Sven-Ola\n");
}
/**
* Optional Private Destructor
*/
static void
my_fini(void)
{
if (0 <= arprefresh_sockfd) {
close(arprefresh_sockfd);
arprefresh_sockfd = -1;
}
}
/*
* Local Variables:
* c-basic-offset: 2
* indent-tabs-mode: nil
* End:
*/
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