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NetBSD/usr.sbin/dhcp/common/socket.c

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/* socket.c
BSD socket interface code... */
/*
* Copyright (c) 1995-2000 Internet Software Consortium.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of The Internet Software Consortium nor the names
* of its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This software has been written for the Internet Software Consortium
* by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
* To learn more about the Internet Software Consortium, see
* ``http://www.isc.org/''. To learn more about Vixie Enterprises,
* see ``http://www.vix.com''. To learn more about Nominum, Inc., see
* ``http://www.nominum.com''.
*/
/* SO_BINDTODEVICE support added by Elliot Poger (poger@leland.stanford.edu).
* This sockopt allows a socket to be bound to a particular interface,
* thus enabling the use of DHCPD on a multihomed host.
* If SO_BINDTODEVICE is defined in your system header files, the use of
* this sockopt will be automatically enabled.
* I have implemented it under Linux; other systems should be doable also.
*/
#ifndef lint
static char copyright[] =
"$Id: socket.c,v 1.1.1.9 2000/04/22 07:11:37 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium. All rights reserved.\n";
#endif /* not lint */
#include "dhcpd.h"
#ifdef USE_SOCKET_FALLBACK
# if !defined (USE_SOCKET_SEND)
# define if_register_send if_register_fallback
# define send_packet send_fallback
# define if_reinitialize_send if_reinitialize_fallback
# endif
#endif
static int once = 0;
/* Reinitializes the specified interface after an address change. This
is not required for packet-filter APIs. */
#if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK)
void if_reinitialize_send (info)
struct interface_info *info;
{
#if 0
#ifndef USE_SOCKET_RECEIVE
once = 0;
close (info -> wfdesc);
#endif
if_register_send (info);
#endif
}
#endif
#ifdef USE_SOCKET_RECEIVE
void if_reinitialize_receive (info)
struct interface_info *info;
{
#if 0
once = 0;
close (info -> rfdesc);
if_register_receive (info);
#endif
}
#endif
#if defined (USE_SOCKET_SEND) || \
defined (USE_SOCKET_RECEIVE) || \
defined (USE_SOCKET_FALLBACK)
/* Generic interface registration routine... */
int if_register_socket (info)
struct interface_info *info;
{
struct sockaddr_in name;
int sock;
int flag;
#if !defined (HAVE_SO_BINDTODEVICE) && !defined (USE_FALLBACK)
/* Make sure only one interface is registered. */
if (once)
log_fatal ("The standard socket API can only support %s",
"hosts with a single network interface.");
once = 1;
#endif
/* Set up the address we're going to bind to. */
name.sin_family = AF_INET;
name.sin_port = local_port;
name.sin_addr.s_addr = INADDR_ANY;
memset (name.sin_zero, 0, sizeof (name.sin_zero));
/* Make a socket... */
if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
log_fatal ("Can't create dhcp socket: %m");
/* Set the REUSEADDR option so that we don't fail to start if
we're being restarted. */
flag = 1;
if (setsockopt (sock, SOL_SOCKET, SO_REUSEADDR,
(char *)&flag, sizeof flag) < 0)
log_fatal ("Can't set SO_REUSEADDR option on dhcp socket: %m");
/* Set the BROADCAST option so that we can broadcast DHCP responses. */
if (setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
(char *)&flag, sizeof flag) < 0)
log_fatal ("Can't set SO_BROADCAST option on dhcp socket: %m");
/* Bind the socket to this interface's IP address. */
if (bind (sock, (struct sockaddr *)&name, sizeof name) < 0)
log_fatal ("Can't bind to dhcp address: %m");
#if defined (HAVE_SO_BINDTODEVICE)
/* Bind this socket to this interface. */
if (info -> ifp &&
setsockopt (sock, SOL_SOCKET, SO_BINDTODEVICE,
(char *)(info -> ifp), sizeof *(info -> ifp)) < 0) {
log_fatal ("setsockopt: SO_BINDTODEVICE: %m");
}
#endif
return sock;
}
#endif /* USE_SOCKET_SEND || USE_SOCKET_RECEIVE || USE_SOCKET_FALLBACK */
#if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK)
void if_register_send (info)
struct interface_info *info;
{
#ifndef USE_SOCKET_RECEIVE
info -> wfdesc = if_register_socket (info);
#if defined (USE_SOCKET_FALLBACK)
/* Fallback only registers for send, but may need to receive as
well. */
info -> rfdesc = info -> wfdesc;
#endif
#else
info -> wfdesc = info -> rfdesc;
#endif
if (!quiet_interface_discovery)
log_info ("Sending on Socket/%s%s%s",
info -> name,
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
#if !defined (USE_SOCKET_FALLBACK)
void if_deregister_send (info)
struct interface_info *info;
{
#ifndef USE_SOCKET_RECEIVE
close (info -> wfdesc);
#endif
info -> wfdesc = -1;
if (!quiet_interface_discovery)
log_info ("Disabling output on Socket/%s%s%s",
info -> name,
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
#endif /* !USE_SOCKET_FALLBACK */
#endif /* USE_SOCKET_SEND || USE_SOCKET_FALLBACK */
#ifdef USE_SOCKET_RECEIVE
void if_register_receive (info)
struct interface_info *info;
{
/* If we're using the socket API for sending and receiving,
we don't need to register this interface twice. */
info -> rfdesc = if_register_socket (info);
if (!quiet_interface_discovery)
log_info ("Listening on Socket/%s%s%s",
info -> name,
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
void if_deregister_receive (info)
struct interface_info *info;
{
close (info -> rfdesc);
info -> rfdesc = -1;
if (!quiet_interface_discovery)
log_info ("Disabling input on Socket/%s%s%s",
info -> name,
(info -> shared_network ? "/" : ""),
(info -> shared_network ?
info -> shared_network -> name : ""));
}
#endif /* USE_SOCKET_RECEIVE */
#if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_FALLBACK)
ssize_t send_packet (interface, packet, raw, len, from, to, hto)
struct interface_info *interface;
struct packet *packet;
struct dhcp_packet *raw;
size_t len;
struct in_addr from;
struct sockaddr_in *to;
struct hardware *hto;
{
int result;
#ifdef IGNORE_HOSTUNREACH
int retry = 0;
do {
#endif
result = sendto (interface -> wfdesc, (char *)raw, len, 0,
(struct sockaddr *)to, sizeof *to);
#ifdef IGNORE_HOSTUNREACH
} while (to -> sin_addr.s_addr == htonl (INADDR_BROADCAST) &&
result < 0 &&
(errno == EHOSTUNREACH ||
errno == ECONNREFUSED) &&
retry++ < 10);
#endif
if (result < 0) {
log_error ("send_packet: %m");
if (errno == ENETUNREACH)
log_error ("send_packet: please consult README file%s",
" regarding broadcast address.");
}
return result;
}
#endif /* USE_SOCKET_SEND || USE_SOCKET_FALLBACK */
#ifdef USE_SOCKET_RECEIVE
ssize_t receive_packet (interface, buf, len, from, hfrom)
struct interface_info *interface;
unsigned char *buf;
size_t len;
struct sockaddr_in *from;
struct hardware *hfrom;
{
SOCKLEN_T flen = sizeof *from;
int result;
#ifdef IGNORE_HOSTUNREACH
int retry = 0;
do {
#endif
result = recvfrom (interface -> rfdesc, (char *)buf, len, 0,
(struct sockaddr *)from, &flen);
#ifdef IGNORE_HOSTUNREACH
} while (result < 0 &&
(errno == EHOSTUNREACH ||
errno == ECONNREFUSED) &&
retry++ < 10);
#endif
return result;
}
#endif /* USE_SOCKET_RECEIVE */
#if defined (USE_SOCKET_FALLBACK)
/* This just reads in a packet and silently discards it. */
isc_result_t fallback_discard (object)
omapi_object_t *object;
{
char buf [1540];
struct sockaddr_in from;
SOCKLEN_T flen = sizeof from;
int status;
struct interface_info *interface;
if (object -> type != dhcp_type_interface)
return ISC_R_INVALIDARG;
interface = (struct interface_info *)object;
status = recvfrom (interface -> wfdesc, buf, sizeof buf, 0,
(struct sockaddr *)&from, &flen);
if (status < 0) {
log_error ("fallback_discard: %m");
return ISC_R_UNEXPECTED;
}
return ISC_R_SUCCESS;
}
#endif /* USE_SOCKET_FALLBACK */
#if defined (USE_SOCKET_SEND)
int can_unicast_without_arp (ip)
struct interface_info *ip;
{
return 0;
}
int can_receive_unicast_unconfigured (ip)
struct interface_info *ip;
{
#if defined (SOCKET_CAN_RECEIVE_UNICAST_UNCONFIGURED)
return 1;
#else
return 0;
#endif
}
/* If we have SO_BINDTODEVICE, set up a fallback interface; otherwise,
do not. */
void maybe_setup_fallback ()
{
#if defined (USE_SOCKET_FALLBACK)
isc_result_t status;
struct interface_info *fbi;
fbi = setup_fallback ();
if (fbi) {
fbi -> wfdesc = if_register_socket (fbi);
fbi -> refcnt = 1;
fbi -> type = dhcp_type_interface;
status = omapi_register_io_object ((omapi_object_t *)fbi,
if_readsocket, 0,
fallback_discard, 0, 0);
if (status != ISC_R_SUCCESS)
log_fatal ("Can't register I/O handle for %s: %s",
fbi -> name, isc_result_totext (status));
}
#endif
}
#endif /* USE_SOCKET_SEND */
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