298 lines
8.5 KiB
C
298 lines
8.5 KiB
C
/* socket.c
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BSD socket interface code... */
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/*
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* Copyright (c) 1995, 1996, 1997, 1998, 1999
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* The Internet Software Consortium. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of The Internet Software Consortium nor the names
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* of its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
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* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This software has been written for the Internet Software Consortium
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* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
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* Enterprises. To learn more about the Internet Software Consortium,
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* see ``http://www.vix.com/isc''. To learn more about Vixie
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* Enterprises, see ``http://www.vix.com''.
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*/
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/* SO_BINDTODEVICE support added by Elliot Poger (poger@leland.stanford.edu).
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* This sockopt allows a socket to be bound to a particular interface,
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* thus enabling the use of DHCPD on a multihomed host.
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* If SO_BINDTODEVICE is defined in your system header files, the use of
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* this sockopt will be automatically enabled.
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* I have implemented it under Linux; other systems should be doable also.
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*/
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#ifndef lint
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static char copyright[] =
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"$Id: socket.c,v 1.26.2.11 1999/03/29 22:07:14 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium. All rights reserved.\n";
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#endif /* not lint */
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#include "dhcpd.h"
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#ifdef USE_SOCKET_FALLBACK
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# define USE_SOCKET_SEND
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# define if_register_send if_register_fallback
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# define send_packet send_fallback
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# define if_reinitialize_send if_reinitialize_fallback
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#endif
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static int once = 0;
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/* Reinitializes the specified interface after an address change. This
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is not required for packet-filter APIs. */
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#ifdef USE_SOCKET_SEND
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void if_reinitialize_send (info)
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struct interface_info *info;
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{
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#if 0
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#ifndef USE_SOCKET_RECEIVE
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once = 0;
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close (info -> wfdesc);
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#endif
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if_register_send (info);
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#endif
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}
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#endif
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#ifdef USE_SOCKET_RECEIVE
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void if_reinitialize_receive (info)
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struct interface_info *info;
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{
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#if 0
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once = 0;
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close (info -> rfdesc);
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if_register_receive (info);
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#endif
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}
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#endif
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#if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_RECEIVE)
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/* Generic interface registration routine... */
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int if_register_socket (info)
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struct interface_info *info;
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{
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struct sockaddr_in name;
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int sock;
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int flag;
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#if !defined (HAVE_SO_BINDTODEVICE) && !defined (USE_FALLBACK)
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/* Make sure only one interface is registered. */
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if (once)
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error ("The standard socket API can only support %s",
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"hosts with a single network interface.");
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once = 1;
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#endif
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/* Set up the address we're going to bind to. */
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name.sin_family = AF_INET;
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name.sin_port = local_port;
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name.sin_addr.s_addr = INADDR_ANY;
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memset (name.sin_zero, 0, sizeof (name.sin_zero));
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/* Make a socket... */
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if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
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error ("Can't create dhcp socket: %m");
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/* Set the REUSEADDR option so that we don't fail to start if
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we're being restarted. */
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flag = 1;
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if (setsockopt (sock, SOL_SOCKET, SO_REUSEADDR,
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(char *)&flag, sizeof flag) < 0)
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error ("Can't set SO_REUSEADDR option on dhcp socket: %m");
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/* Set the BROADCAST option so that we can broadcast DHCP responses. */
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if (setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
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(char *)&flag, sizeof flag) < 0)
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error ("Can't set SO_BROADCAST option on dhcp socket: %m");
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/* Bind the socket to this interface's IP address. */
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if (bind (sock, (struct sockaddr *)&name, sizeof name) < 0)
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error ("Can't bind to dhcp address: %m");
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#if defined (HAVE_SO_BINDTODEVICE)
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/* Bind this socket to this interface. */
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if (info -> ifp &&
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setsockopt (sock, SOL_SOCKET, SO_BINDTODEVICE,
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(char *)(info -> ifp), sizeof *(info -> ifp)) < 0) {
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error("setsockopt: SO_BINDTODEVICE: %m");
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}
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#endif
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return sock;
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}
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#endif /* USE_SOCKET_SEND || USE_SOCKET_RECEIVE */
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#ifdef USE_SOCKET_SEND
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void if_register_send (info)
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struct interface_info *info;
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{
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#ifndef USE_SOCKET_RECEIVE
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info -> wfdesc = if_register_socket (info);
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#else
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info -> wfdesc = info -> rfdesc;
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#endif
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if (!quiet_interface_discovery)
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note ("Sending on Socket/%s%s%s",
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info -> name,
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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}
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#endif /* USE_SOCKET_SEND */
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#ifdef USE_SOCKET_RECEIVE
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void if_register_receive (info)
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struct interface_info *info;
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{
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/* If we're using the socket API for sending and receiving,
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we don't need to register this interface twice. */
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info -> rfdesc = if_register_socket (info);
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if (!quiet_interface_discovery)
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note ("Listening on Socket/%s%s%s",
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info -> name,
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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}
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#endif /* USE_SOCKET_RECEIVE */
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#ifdef USE_SOCKET_SEND
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ssize_t send_packet (interface, packet, raw, len, from, to, hto)
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struct interface_info *interface;
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struct packet *packet;
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struct dhcp_packet *raw;
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size_t len;
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struct in_addr from;
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struct sockaddr_in *to;
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struct hardware *hto;
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{
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int result;
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#ifdef IGNORE_HOSTUNREACH
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int retry = 0;
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do {
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#endif
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result = sendto (interface -> wfdesc, (char *)raw, len, 0,
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(struct sockaddr *)to, sizeof *to);
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#ifdef IGNORE_HOSTUNREACH
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} while (to -> sin_addr.s_addr == htonl (INADDR_BROADCAST) &&
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result < 0 &&
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(errno == EHOSTUNREACH ||
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errno == ECONNREFUSED) &&
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retry++ < 10);
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#endif
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if (result < 0) {
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warn ("send_packet: %m");
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if (errno == ENETUNREACH)
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warn ("send_packet: please consult README file %s",
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"regarding broadcast address.");
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}
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return result;
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}
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#endif /* USE_SOCKET_SEND */
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#ifdef USE_SOCKET_RECEIVE
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ssize_t receive_packet (interface, buf, len, from, hfrom)
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struct interface_info *interface;
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unsigned char *buf;
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size_t len;
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struct sockaddr_in *from;
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struct hardware *hfrom;
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{
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int flen = sizeof *from;
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int result;
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#ifdef IGNORE_HOSTUNREACH
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int retry = 0;
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do {
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#endif
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result = recvfrom (interface -> rfdesc, (char *)buf, len, 0,
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(struct sockaddr *)from, &flen);
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#ifdef IGNORE_HOSTUNREACH
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} while (result < 0 &&
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(errno == EHOSTUNREACH ||
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errno == ECONNREFUSED) &&
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retry++ < 10);
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#endif
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return result;
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}
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#endif /* USE_SOCKET_RECEIVE */
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#ifdef USE_SOCKET_SEND
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/* This just reads in a packet and silently discards it. */
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void fallback_discard (protocol)
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struct protocol *protocol;
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{
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char buf [1540];
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struct sockaddr_in from;
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int flen = sizeof from;
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int status;
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struct interface_info *interface = protocol -> local;
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status = recvfrom (interface -> wfdesc, buf, sizeof buf, 0,
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(struct sockaddr *)&from, &flen);
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if (status < 0)
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warn ("fallback_discard: %m");
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}
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#endif /* USE_SOCKET_SEND */
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#if defined (USE_SOCKET_SEND) && !defined (USE_SOCKET_FALLBACK)
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int can_unicast_without_arp ()
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{
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return 0;
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}
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int can_receive_unicast_unconfigured (ip)
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struct interface_info *ip;
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{
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#if defined (SOCKET_CAN_RECEIVE_UNICAST_UNCONFIGURED)
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return 1;
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#else
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return 0;
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#endif
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}
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/* If we have SO_BINDTODEVICE, set up a fallback interface; otherwise,
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do not. */
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void maybe_setup_fallback ()
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{
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#if defined (SO_BINDTODEVICE)
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struct interface_info *fbi;
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fbi = setup_fallback ();
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if (fbi) {
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fbi -> wfdesc = if_register_socket (fbi);
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add_protocol ("fallback",
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fbi -> wfdesc, fallback_discard, fbi);
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}
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#endif
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}
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#endif /* USE_SOCKET_SEND && !USE_SOCKET_FALLBACK */
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