src/libsystemd-network/dhcp6-network.c

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  This file is part of systemd.

  Copyright (C) 2014 Intel Corporation. All rights reserved.

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <linux/if_packet.h>

#include "dhcp6-internal.h"
#include "dhcp6-protocol.h"
#include "fd-util.h"
#include "socket-util.h"

int dhcp6_network_bind_udp_socket(int index, struct in6_addr *local_address) {
        union sockaddr_union src = {
                .in6.sin6_family = AF_INET6,
                .in6.sin6_port = htobe16(DHCP6_PORT_CLIENT),
                .in6.sin6_scope_id = index,
        };
        _cleanup_close_ int s = -1;
        int r, off = 0, on = 1;

        assert(index > 0);
        assert(local_address);

        src.in6.sin6_addr = *local_address;

        s = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_UDP);
        if (s < 0)
                return -errno;

        r = setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
        if (r < 0)
                return -errno;

        r = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, sizeof(off));
        if (r < 0)
                return -errno;

        r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
        if (r < 0)
                return -errno;

        r = bind(s, &src.sa, sizeof(src.in6));
        if (r < 0)
                return -errno;

        r = s;
        s = -1;
        return r;
}

int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address,
                                  const void *packet, size_t len) {
        union sockaddr_union dest = {
                .in6.sin6_family = AF_INET6,
                .in6.sin6_port = htobe16(DHCP6_PORT_SERVER),
        };
        int r;

        assert(server_address);

        memcpy(&dest.in6.sin6_addr, server_address, sizeof(dest.in6.sin6_addr));

        r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in6));
        if (r < 0)
                return -errno;

        return 0;
}