src/libsystemd-network/dhcp6-network.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright (C) 2014 Intel Corporation. All rights reserved.
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <errno.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 "dhcp6-internal.h"
  32 #include "dhcp6-protocol.h"
  33 #include "fd-util.h"
  34 #include "socket-util.h"
  35
  36 int dhcp6_network_bind_udp_socket(int index, struct in6_addr *local_address) {
  37         union sockaddr_union src = {
  38                 .in6.sin6_family = AF_INET6,
  39                 .in6.sin6_port = htobe16(DHCP6_PORT_CLIENT),
  40                 .in6.sin6_scope_id = index,
  41         };
  42         _cleanup_close_ int s = -1;
  43         int r, off = 0, on = 1;
  44
  45         assert(index > 0);
  46         assert(local_address);
  47
  48         src.in6.sin6_addr = *local_address;
  49
  50         s = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_UDP);
  51         if (s < 0)
  52                 return -errno;
  53
  54         r = setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
  55         if (r < 0)
  56                 return -errno;
  57
  58         r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, sizeof(off));
  59         if (r < 0)
  60                 return -errno;
  61
  62         r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
  63         if (r < 0)
  64                 return -errno;
  65
  66         r = bind(s, &src.sa, sizeof(src.in6));
  67         if (r < 0)
  68                 return -errno;
  69
  70         return TAKE_FD(s);
  71 }
  72
  73 int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address,
  74                                   const void *packet, size_t len) {
  75         union sockaddr_union dest = {
  76                 .in6.sin6_family = AF_INET6,
  77                 .in6.sin6_port = htobe16(DHCP6_PORT_SERVER),
  78         };
  79         int r;
  80
  81         assert(server_address);
  82
  83         memcpy(&dest.in6.sin6_addr, server_address, sizeof(dest.in6.sin6_addr));
  84
  85         r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in6));
  86         if (r < 0)
  87                 return -errno;
  88
  89         return 0;
  90 }