common/raw.c

   1 /* raw.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) 2004-2017 by Internet Systems Consortium, Inc. ("ISC")
  20  * Copyright (c) 1995-2003 by Internet Software Consortium
  21  *
  22  * This Source Code Form is subject to the terms of the Mozilla Public
  23  * License, v. 2.0. If a copy of the MPL was not distributed with this
  24  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  27  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  28  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  29  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  30  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  31  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  32  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  33  *
  34  *   Internet Systems Consortium, Inc.
  35  *   PO Box 360
  36  *   Newmarket, NH 03857 USA
  37  *   <info@isc.org>
  38  *   https://www.isc.org/
  39  *
  40  */
  41
  42 #include "dhcpd.h"
  43
  44 #if defined (USE_RAW_SEND)
  45 #include <sys/uio.h>
  46
  47 /* Generic interface registration routine... */
  48 void if_register_send (info)
  49         struct interface_info *info;
  50 {
  51         struct sockaddr_in name;
  52         int sock;
  53         struct socklist *tmp;
  54         int flag;
  55
  56         /* Set up the address we're going to connect to. */
  57         name.sin_family = AF_INET;
  58         name.sin_port = relay_port ? relay_port : local_port;
  59         name.sin_addr.s_addr = htonl (INADDR_BROADCAST);
  60         memset (name.sin_zero, 0, sizeof (name.sin_zero));
  61
  62         /* List addresses on which we're listening. */
  63         if (!quiet_interface_discovery)
  64                 log_info ("Sending on %s, port %d",
  65                       piaddr (info -> address), htons (name.sin_port));
  66         if ((sock = socket (AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
  67                 log_fatal ("Can't create dhcp socket: %m");
  68
  69         /* Set the BROADCAST option so that we can broadcast DHCP responses. */
  70         flag = 1;
  71         if (setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
  72                         &flag, sizeof flag) < 0)
  73                 log_fatal ("Can't set SO_BROADCAST option on dhcp socket: %m");
  74
  75         /* Set the IP_HDRINCL flag so that we can supply our own IP
  76            headers... */
  77         if (setsockopt (sock, IPPROTO_IP, IP_HDRINCL, &flag, sizeof flag) < 0)
  78                 log_fatal ("Can't set IP_HDRINCL flag: %m");
  79
  80         info -> wfdesc = sock;
  81         if (!quiet_interface_discovery)
  82                 log_info ("Sending on   Raw/%s%s%s",
  83                       info -> name,
  84                       (info -> shared_network ? "/" : ""),
  85                       (info -> shared_network ?
  86                        info -> shared_network -> name : ""));
  87 }
  88
  89 void if_deregister_send (info)
  90         struct interface_info *info;
  91 {
  92         close (info -> wfdesc);
  93         info -> wfdesc = -1;
  94
  95         if (!quiet_interface_discovery)
  96                 log_info ("Disabling output on Raw/%s%s%s",
  97                       info -> name,
  98                       (info -> shared_network ? "/" : ""),
  99                       (info -> shared_network ?
 100                        info -> shared_network -> name : ""));
 101 }
 102
 103 size_t send_packet (interface, packet, raw, len, from, to, hto)
 104         struct interface_info *interface;
 105         struct packet *packet;
 106         struct dhcp_packet *raw;
 107         size_t len;
 108         struct in_addr from;
 109         struct sockaddr_in *to;
 110         struct hardware *hto;
 111 {
 112         unsigned char buf [256];
 113         int bufp = 0;
 114         struct iovec iov [2];
 115         int result;
 116
 117         /* Assemble the headers... */
 118         assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
 119                                 to -> sin_addr.s_addr, to -> sin_port,
 120                                 (unsigned char *)raw, len);
 121
 122         /* Fire it off */
 123         iov [0].iov_base = (char *)buf;
 124         iov [0].iov_len = bufp;
 125         iov [1].iov_base = (char *)raw;
 126         iov [1].iov_len = len;
 127
 128         result = writev(interface -> wfdesc, iov, 2);
 129         if (result < 0)
 130                 log_error ("send_packet: %m");
 131         return result;
 132 }
 133 #endif /* USE_SOCKET_SEND */