common/raw.c

   1 /* socket.c
   2
   3    BSD raw socket interface code... */
   4
   5 /* XXX
   6
   7    It's not clear how this should work, and that lack of clarity is
   8    terribly detrimental to the NetBSD 1.1 kernel - it crashes and
   9    burns.
  10
  11    Using raw sockets ought to be a big win over using BPF or something
  12    like it, because you don't need to deal with the complexities of
  13    the physical layer, but it appears not to be possible with existing
  14    raw socket implementations.  This may be worth revisiting in the
  15    future.  For now, this code can probably be considered a curiosity.
  16    Sigh. */
  17
  18 /*
  19  * Copyright (c) 1996-1999 Internet Software Consortium.
  20  * Use is subject to license terms which appear in the file named
  21  * ISC-LICENSE that should have accompanied this file when you
  22  * received it.   If a file named ISC-LICENSE did not accompany this
  23  * file, or you are not sure the one you have is correct, you may
  24  * obtain an applicable copy of the license at:
  25  *
  26  *             http://www.isc.org/isc-license-1.0.html.
  27  *
  28  * This file is part of the ISC DHCP distribution.   The documentation
  29  * associated with this file is listed in the file DOCUMENTATION,
  30  * included in the top-level directory of this release.
  31  *
  32  * Support and other services are available for ISC products - see
  33  * http://www.isc.org for more information.
  34  */
  35
  36 #ifndef lint
  37 static char copyright[] =
  38 "$Id: raw.c,v 1.15 1999/03/16 06:37:50 mellon Exp $ Copyright (c) 1995, 1996 The Internet Software Consortium.  All rights reserved.\n";
  39 #endif /* not lint */
  40
  41 #include "dhcpd.h"
  42
  43 #if defined (USE_RAW_SEND)
  44 #include <sys/uio.h>
  45
  46 /* Generic interface registration routine... */
  47 void if_register_send (info)
  48         struct interface_info *info;
  49 {
  50         struct sockaddr_in name;
  51         int sock;
  52         struct socklist *tmp;
  53         int flag;
  54
  55         /* Set up the address we're going to connect to. */
  56         name.sin_family = AF_INET;
  57         name.sin_port = local_port;
  58         name.sin_addr.s_addr = htonl (INADDR_BROADCAST);
  59         memset (name.sin_zero, 0, sizeof (name.sin_zero));
  60
  61         /* List addresses on which we're listening. */
  62         if (!quiet_interface_discovery)
  63                 log_info ("Sending on %s, port %d",
  64                       piaddr (info -> address), htons (local_port));
  65         if ((sock = socket (AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
  66                 log_fatal ("Can't create dhcp socket: %m");
  67
  68         /* Set the BROADCAST option so that we can broadcast DHCP responses. */
  69         flag = 1;
  70         if (setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
  71                         &flag, sizeof flag) < 0)
  72                 log_fatal ("Can't set SO_BROADCAST option on dhcp socket: %m");
  73
  74         /* Set the IP_HDRINCL flag so that we can supply our own IP
  75            headers... */
  76         if (setsockopt (sock, IPPROTO_IP, IP_HDRINCL, &flag, sizeof flag) < 0)
  77                 log_fatal ("Can't set IP_HDRINCL flag: %m");
  78
  79         info -> wfdesc = sock;
  80         if (!quiet_interface_discovery)
  81                 log_info ("Sending on   Raw/%s%s%s",
  82                       info -> name,
  83                       (info -> shared_network ? "/" : ""),
  84                       (info -> shared_network ?
  85                        info -> shared_network -> name : ""));
  86 }
  87
  88 size_t send_packet (interface, packet, raw, len, from, to, hto)
  89         struct interface_info *interface;
  90         struct packet *packet;
  91         struct dhcp_packet *raw;
  92         size_t len;
  93         struct in_addr from;
  94         struct sockaddr_in *to;
  95         struct hardware *hto;
  96 {
  97         unsigned char buf [256];
  98         int bufp = 0;
  99         struct iovec iov [2];
 100         int result;
 101
 102         /* Assemble the headers... */
 103         assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
 104                                 to -> sin_addr.s_addr, to -> sin_port,
 105                                 (unsigned char *)raw, len);
 106
 107         /* Fire it off */
 108         iov [0].iov_base = (char *)buf;
 109         iov [0].iov_len = bufp;
 110         iov [1].iov_base = (char *)raw;
 111         iov [1].iov_len = len;
 112
 113         result = writev(interface -> wfdesc, iov, 2);
 114         if (result < 0)
 115                 log_error ("send_packet: %m");
 116         return result;
 117 }
 118 #endif /* USE_SOCKET_SEND */