238 lines
7.7 KiB
C
238 lines
7.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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This file is part of systemd.
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Copyright (C) 2014 Intel Corporation. All rights reserved.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <netinet/icmp6.h>
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#include <netinet/in.h>
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#include <netinet/ip6.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <net/if.h>
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#include <linux/if_packet.h>
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#include "fd-util.h"
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#include "icmp6-util.h"
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#include "socket-util.h"
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#include "in-addr-util.h"
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#define IN6ADDR_ALL_ROUTERS_MULTICAST_INIT \
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{ { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 } } }
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#define IN6ADDR_ALL_NODES_MULTICAST_INIT \
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{ { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } } }
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static int icmp6_bind_router_message(const struct icmp6_filter *filter,
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const struct ipv6_mreq *mreq) {
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int index = mreq->ipv6mr_interface;
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_cleanup_close_ int s = -1;
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char ifname[IF_NAMESIZE] = "";
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static const int zero = 0, one = 1, hops = 255;
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int r;
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s = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_ICMPV6);
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if (s < 0)
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return -errno;
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r = setsockopt(s, IPPROTO_ICMPV6, ICMP6_FILTER, filter, sizeof(*filter));
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if (r < 0)
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return -errno;
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r = setsockopt(s, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, mreq, sizeof(*mreq));
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if (r < 0)
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return -errno;
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/* RFC 3315, section 6.7, bullet point 2 may indicate that an
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IPV6_PKTINFO socket option also applies for ICMPv6 multicast.
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Empirical experiments indicates otherwise and therefore an
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IPV6_MULTICAST_IF socket option is used here instead */
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r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_IF, &index, sizeof(index));
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if (r < 0)
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return -errno;
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r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &zero, sizeof(zero));
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if (r < 0)
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return -errno;
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r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, sizeof(hops));
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if (r < 0)
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return -errno;
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r = setsockopt(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hops, sizeof(hops));
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if (r < 0)
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return -errno;
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r = setsockopt(s, SOL_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
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if (r < 0)
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return -errno;
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r = setsockopt(s, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
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if (r < 0)
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return -errno;
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if (if_indextoname(index, ifname) == 0)
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return -errno;
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r = setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
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if (r < 0)
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return -errno;
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return TAKE_FD(s);
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}
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int icmp6_bind_router_solicitation(int index) {
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struct icmp6_filter filter = {};
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struct ipv6_mreq mreq = {
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.ipv6mr_multiaddr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
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.ipv6mr_interface = index,
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};
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ICMP6_FILTER_SETBLOCKALL(&filter);
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ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);
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return icmp6_bind_router_message(&filter, &mreq);
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}
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int icmp6_bind_router_advertisement(int index) {
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struct icmp6_filter filter = {};
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struct ipv6_mreq mreq = {
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.ipv6mr_multiaddr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
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.ipv6mr_interface = index,
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};
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ICMP6_FILTER_SETBLOCKALL(&filter);
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ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
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return icmp6_bind_router_message(&filter, &mreq);
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}
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int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
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struct sockaddr_in6 dst = {
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.sin6_family = AF_INET6,
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.sin6_addr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
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};
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struct {
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struct nd_router_solicit rs;
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struct nd_opt_hdr rs_opt;
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struct ether_addr rs_opt_mac;
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} _packed_ rs = {
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.rs.nd_rs_type = ND_ROUTER_SOLICIT,
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.rs_opt.nd_opt_type = ND_OPT_SOURCE_LINKADDR,
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.rs_opt.nd_opt_len = 1,
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};
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struct iovec iov = {
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.iov_base = &rs,
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.iov_len = sizeof(rs),
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};
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struct msghdr msg = {
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.msg_name = &dst,
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.msg_namelen = sizeof(dst),
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.msg_iov = &iov,
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.msg_iovlen = 1,
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};
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int r;
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assert(s >= 0);
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assert(ether_addr);
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rs.rs_opt_mac = *ether_addr;
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r = sendmsg(s, &msg, 0);
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if (r < 0)
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return -errno;
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return 0;
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}
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int icmp6_receive(int fd, void *buffer, size_t size, struct in6_addr *dst,
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triple_timestamp *timestamp) {
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union {
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struct cmsghdr cmsghdr;
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uint8_t buf[CMSG_SPACE(sizeof(int)) + /* ttl */
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CMSG_SPACE(sizeof(struct timeval))];
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} control = {};
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struct iovec iov = {};
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union sockaddr_union sa = {};
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struct msghdr msg = {
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.msg_name = &sa.sa,
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.msg_namelen = sizeof(sa),
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.msg_iov = &iov,
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.msg_iovlen = 1,
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.msg_control = &control,
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.msg_controllen = sizeof(control),
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};
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struct cmsghdr *cmsg;
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ssize_t len;
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iov.iov_base = buffer;
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iov.iov_len = size;
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len = recvmsg(fd, &msg, MSG_DONTWAIT);
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if (len < 0) {
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if (IN_SET(errno, EAGAIN, EINTR))
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return 0;
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return -errno;
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}
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if ((size_t) len != size)
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return -EINVAL;
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if (msg.msg_namelen == sizeof(struct sockaddr_in6) &&
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sa.in6.sin6_family == AF_INET6) {
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*dst = sa.in6.sin6_addr;
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if (in_addr_is_link_local(AF_INET6, (union in_addr_union*) dst) <= 0)
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return -EADDRNOTAVAIL;
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} else if (msg.msg_namelen > 0)
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return -EPFNOSUPPORT;
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/* namelen == 0 only happens when running the test-suite over a socketpair */
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assert(!(msg.msg_flags & MSG_CTRUNC));
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assert(!(msg.msg_flags & MSG_TRUNC));
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CMSG_FOREACH(cmsg, &msg) {
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if (cmsg->cmsg_level == SOL_IPV6 &&
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cmsg->cmsg_type == IPV6_HOPLIMIT &&
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cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
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int hops = *(int*) CMSG_DATA(cmsg);
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if (hops != 255)
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return -EMULTIHOP;
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}
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if (cmsg->cmsg_level == SOL_SOCKET &&
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cmsg->cmsg_type == SO_TIMESTAMP &&
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cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval)))
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triple_timestamp_from_realtime(timestamp, timeval_load((struct timeval*) CMSG_DATA(cmsg)));
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}
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if (!triple_timestamp_is_set(timestamp))
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triple_timestamp_get(timestamp);
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return 0;
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}
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