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/*
* Copyright (C) 2014-2016 Tobias Klauser <tklauser@distanz.ch>
*
* This file is part of llmnrd.
*
* llmnrd is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* llmnrd 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 llmnrd. If not, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include "llmnr-packet.h"
#include "log.h"
#include "socket.h"
static const int YES = 1;
static const int TTL = 255;
int socket_open_ipv4(uint16_t port)
{
int sock;
struct sockaddr_in sa;
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
log_err("Failed to open UDP socket: %s\n", strerror(errno));
return -1;
}
/* pass pktinfo struct on received packets */
if (setsockopt(sock, IPPROTO_IP, IP_PKTINFO, &YES, sizeof(YES)) < 0) {
log_err("Failed to set IPv4 packet info socket option: %s\n", strerror(errno));
goto err;
}
/* RFC 4795, section 2.5 recommends to set TTL to 255 for UDP */
if (setsockopt(sock, IPPROTO_IP, IP_TTL, &TTL, sizeof(TTL)) < 0) {
log_err("Failed to set IPv4 unicast TTL socket option: %s\n", strerror(errno));
goto err;
}
if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, &TTL, sizeof(TTL)) < 0) {
log_err("Failed to set IPv4 multicast TTL socket option: %s\n", strerror(errno));
goto err;
}
/* bind the socket */
memset(&sa, 0, sizeof(sa));
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = INADDR_ANY;
sa.sin_port = htons(port);
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
log_err("Failed to bind() socket: %s\n", strerror(errno));
goto err;
}
return sock;
err:
close(sock);
return -1;
}
int socket_open_ipv6(uint16_t port)
{
int sock, opt_pktinfo;
struct sockaddr_in6 sa;
sock = socket(AF_INET6, SOCK_DGRAM, 0);
if (sock < 0) {
log_err("Failed to open UDP socket: %s\n", strerror(errno));
return -1;
}
/* pass pktinfo struct on received packets */
#if defined(IPV6_RECVPKTINFO)
opt_pktinfo = IPV6_RECVPKTINFO;
#elif defined(IPV6_PKTINFO)
opt_pktinfo = IPV6_PKTINFO;
#endif
if (setsockopt(sock, IPPROTO_IPV6, opt_pktinfo, &YES, sizeof(YES)) < 0) {
log_err("Failed to set IPv6 packet info socket option: %s\n", strerror(errno));
goto err;
}
/* RFC 4795, section 2.5 recommends to set TTL to 255 for UDP */
if (setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &TTL, sizeof(TTL)) < 0) {
log_err("Failed to set IPv6 unicast hops socket option: %s\n", strerror(errno));
goto err;
}
if (setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &TTL, sizeof(TTL)) < 0) {
log_err("Failed to set IPv6 multicast hops socket option: %s\n", strerror(errno));
goto err;
}
/* IPv6 only socket */
if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &YES, sizeof(YES)) < 0) {
log_err("Failed to set IPv6 only socket option: %s\n", strerror(errno));
goto err;
}
/* bind the socket */
memset(&sa, 0, sizeof(sa));
sa.sin6_family = AF_INET6;
sa.sin6_port = htons(port);
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
log_err("Failed to bind() socket: %s\n", strerror(errno));
goto err;
}
return sock;
err:
close(sock);
return -1;
}
int socket_open_rtnl(void)
{
int sock;
struct sockaddr_nl sa;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
log_err("Failed to open netlink route socket: %s\n", strerror(errno));
return -1;
}
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
/*
* listen for following events:
* - network interface create/delete/up/down
* - IPv4 address add/delete
* - IPv6 address add/delete
*/
sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
log_err("Failed to bind() netlink socket: %s\n", strerror(errno));
goto err;
}
return sock;
err:
close(sock);
return -1;
}
int socket_mcast_group_ipv4(int sock, unsigned int ifindex, bool join)
{
struct ip_mreqn mreq;
char ifname[IF_NAMESIZE];
/* silently ignore, we might not be listening on an IPv4 socket */
if (sock < 0)
return -1;
memset(&mreq, 0, sizeof(mreq));
mreq.imr_ifindex = ifindex;
mreq.imr_address.s_addr = INADDR_ANY;
inet_pton(AF_INET, LLMNR_IPV4_MCAST_ADDR, &mreq.imr_multiaddr);
if (setsockopt(sock, IPPROTO_IP, join ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP,
&mreq, sizeof(mreq)) < 0) {
log_err("Failed to join IPv4 multicast group on interface %s: %s\n",
if_indextoname(ifindex, ifname), strerror(errno));
return -1;
}
return 0;
}
int socket_mcast_group_ipv6(int sock, unsigned int ifindex, bool join)
{
struct ipv6_mreq mreq6;
char ifname[IF_NAMESIZE];
/* silently ignore, we might not be listening on an IPv6 socket */
if (sock < 0)
return -1;
memset(&mreq6, 0, sizeof(mreq6));
mreq6.ipv6mr_interface = ifindex;
inet_pton(AF_INET6, LLMNR_IPV6_MCAST_ADDR, &mreq6.ipv6mr_multiaddr);
if (setsockopt(sock, IPPROTO_IPV6, join ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP,
&mreq6, sizeof(mreq6)) < 0) {
log_err("Failed to join IPv6 multicast group on interface %s: %s\n",
if_indextoname(ifindex, ifname), strerror(errno));
return -1;
}
return 0;
}
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