src/libsystemd-network/icmp6-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2014 Intel Corporation. All rights reserved.
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <netinet/icmp6.h>
  22 #include <netinet/in.h>
  23 #include <netinet/ip6.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <sys/socket.h>
  27 #include <sys/types.h>
  28 #include <unistd.h>
  29 #include <linux/if_packet.h>
  30
  31 #include "fd-util.h"
  32 #include "icmp6-util.h"
  33 #include "socket-util.h"
  34
  35 #define IN6ADDR_ALL_ROUTERS_MULTICAST_INIT \
  36         { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
  37               0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 } } }
  38
  39 #define IN6ADDR_ALL_NODES_MULTICAST_INIT \
  40         { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
  41               0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } } }
  42
  43 int icmp6_bind_router_solicitation(int index) {
  44         struct icmp6_filter filter = { };
  45         struct ipv6_mreq mreq = {
  46                 .ipv6mr_multiaddr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
  47                 .ipv6mr_interface = index,
  48         };
  49         _cleanup_close_ int s = -1;
  50         int r, zero = 0, one = 1, hops = 255;
  51
  52         s = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_ICMPV6);
  53         if (s < 0)
  54                 return -errno;
  55
  56         ICMP6_FILTER_SETBLOCKALL(&filter);
  57         ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);
  58         r = setsockopt(s, IPPROTO_ICMPV6, ICMP6_FILTER, &filter, sizeof(filter));
  59         if (r < 0)
  60                 return -errno;
  61
  62         /* RFC 3315, section 6.7, bullet point 2 may indicate that an
  63            IPV6_PKTINFO socket option also applies for ICMPv6 multicast.
  64            Empirical experiments indicates otherwise and therefore an
  65            IPV6_MULTICAST_IF socket option is used here instead */
  66         r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_IF, &index, sizeof(index));
  67         if (r < 0)
  68                 return -errno;
  69
  70         r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &zero, sizeof(zero));
  71         if (r < 0)
  72                 return -errno;
  73
  74         r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, sizeof(hops));
  75         if (r < 0)
  76                 return -errno;
  77
  78         r = setsockopt(s, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
  79         if (r < 0)
  80                 return -errno;
  81
  82         r = setsockopt(s, SOL_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
  83         if (r < 0)
  84                 return -errno;
  85
  86         r = s;
  87         s = -1;
  88         return r;
  89 }
  90
  91 int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
  92         struct sockaddr_in6 dst = {
  93                 .sin6_family = AF_INET6,
  94                 .sin6_addr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
  95         };
  96         struct {
  97                 struct nd_router_solicit rs;
  98                 struct nd_opt_hdr rs_opt;
  99                 struct ether_addr rs_opt_mac;
 100         } _packed_ rs = {
 101                 .rs.nd_rs_type = ND_ROUTER_SOLICIT,
 102                 .rs_opt.nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 103                 .rs_opt.nd_opt_len = 1,
 104         };
 105         struct iovec iov = {
 106                 .iov_base = &rs,
 107                 .iov_len = sizeof(rs),
 108         };
 109         struct msghdr msg = {
 110                 .msg_name = &dst,
 111                 .msg_namelen = sizeof(dst),
 112                 .msg_iov = &iov,
 113                 .msg_iovlen = 1,
 114         };
 115         int r;
 116
 117         assert(s >= 0);
 118         assert(ether_addr);
 119
 120         rs.rs_opt_mac = *ether_addr;
 121
 122         r = sendmsg(s, &msg, 0);
 123         if (r < 0)
 124                 return -errno;
 125
 126         return 0;
 127 }