421 lines
12 KiB
C
421 lines
12 KiB
C
/* nit.c
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Network Interface Tap (NIT) network interface code, by Ted Lemon
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with one crucial tidbit of help from Stu Grossmen. */
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996-2003 by Internet Software Consortium
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Internet Systems Consortium, Inc.
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* 950 Charter Street
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* Redwood City, CA 94063
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* <info@isc.org>
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* http://www.isc.org/
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*
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* This software has been written for Internet Systems Consortium
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* by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
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* To learn more about Internet Systems Consortium, see
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* ``http://www.isc.org/''. To learn more about Vixie Enterprises,
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* see ``http://www.vix.com''. To learn more about Nominum, Inc., see
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* ``http://www.nominum.com''.
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*/
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#ifndef lint
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static char copyright[] =
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"$Id: nit.c,v 1.3 2005/08/11 17:13:21 drochner Exp $ Copyright (c) 2004 Internet Systems Consortium. All rights reserved.\n";
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#endif /* not lint */
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#include "dhcpd.h"
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#if defined (USE_NIT_SEND) || defined (USE_NIT_RECEIVE)
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#include <sys/ioctl.h>
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#include <sys/uio.h>
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#include <sys/time.h>
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#include <net/nit.h>
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#include <net/nit_if.h>
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#include <net/nit_pf.h>
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#include <net/nit_buf.h>
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#include <sys/stropts.h>
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#include <net/packetfilt.h>
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#include <netinet/in_systm.h>
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#include "includes/netinet/ip.h"
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#include "includes/netinet/udp.h"
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#include "includes/netinet/if_ether.h"
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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_NIT_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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}
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#endif
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#ifdef USE_NIT_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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}
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#endif
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/* Called by get_interface_list for each interface that's discovered.
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Opens a packet filter for each interface and adds it to the select
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mask. */
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int if_register_nit (info)
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struct interface_info *info;
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{
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int sock;
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char filename[50];
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struct ifreq ifr;
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struct strioctl sio;
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/* Open a NIT device */
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sock = open ("/dev/nit", O_RDWR);
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if (sock < 0)
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log_fatal ("Can't open NIT device for %s: %m", info -> name);
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/* Set the NIT device to point at this interface. */
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sio.ic_cmd = NIOCBIND;
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sio.ic_len = sizeof *(info -> ifp);
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sio.ic_dp = (char *)(info -> ifp);
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sio.ic_timout = INFTIM;
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if (ioctl (sock, I_STR, &sio) < 0)
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log_fatal ("Can't attach interface %s to nit device: %m",
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info -> name);
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/* Get the low-level address... */
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sio.ic_cmd = SIOCGIFADDR;
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sio.ic_len = sizeof ifr;
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sio.ic_dp = (char *)𝔦
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sio.ic_timout = INFTIM;
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if (ioctl (sock, I_STR, &sio) < 0)
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log_fatal ("Can't get physical layer address for %s: %m",
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info -> name);
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/* XXX code below assumes ethernet interface! */
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info -> hw_address.hlen = 7;
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info -> hw_address.hbuf [0] = ARPHRD_ETHER;
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memcpy (&info -> hw_address.hbuf [1],
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ifr.ifr_ifru.ifru_addr.sa_data, 6);
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if (ioctl (sock, I_PUSH, "pf") < 0)
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log_fatal ("Can't push packet filter onto NIT for %s: %m",
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info -> name);
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return sock;
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}
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#endif /* USE_NIT_SEND || USE_NIT_RECEIVE */
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#ifdef USE_NIT_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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/* If we're using the nit API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_NIT_RECEIVE
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struct packetfilt pf;
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struct strioctl sio;
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info -> wfdesc = if_register_nit (info);
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pf.Pf_Priority = 0;
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pf.Pf_FilterLen = 1;
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pf.Pf_Filter [0] = ENF_PUSHZERO;
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/* Set up an NIT filter that rejects everything... */
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sio.ic_cmd = NIOCSETF;
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sio.ic_len = sizeof pf;
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sio.ic_dp = (char *)&pf;
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sio.ic_timout = INFTIM;
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if (ioctl (info -> wfdesc, I_STR, &sio) < 0)
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log_fatal ("Can't set NIT filter: %m");
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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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log_info ("Sending on NIT/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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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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void if_deregister_send (info)
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struct interface_info *info;
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{
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/* If we're using the nit API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_NIT_RECEIVE
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close (info -> wfdesc);
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#endif
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info -> wfdesc = -1;
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if (!quiet_interface_discovery)
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log_info ("Disabling output on NIT/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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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_NIT_SEND */
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#ifdef USE_NIT_RECEIVE
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/* Packet filter program...
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XXX Changes to the filter program may require changes to the constant
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offsets used in if_register_send to patch the NIT program! XXX */
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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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int flag = 1;
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u_int32_t x;
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struct packetfilt pf;
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struct strioctl sio;
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u_int16_t addr [2];
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struct timeval t;
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/* Open a NIT device and hang it on this interface... */
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info -> rfdesc = if_register_nit (info);
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/* Set the snap length to 0, which means always take the whole
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packet. */
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x = 0;
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if (ioctl (info -> rfdesc, NIOCSSNAP, &x) < 0)
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log_fatal ("Can't set NIT snap length on %s: %m", info -> name);
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/* Set the stream to byte stream mode */
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if (ioctl (info -> rfdesc, I_SRDOPT, RMSGN) != 0)
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log_info ("I_SRDOPT failed on %s: %m", info -> name);
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#if 0
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/* Push on the chunker... */
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if (ioctl (info -> rfdesc, I_PUSH, "nbuf") < 0)
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log_fatal ("Can't push chunker onto NIT STREAM: %m");
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/* Set the timeout to zero. */
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t.tv_sec = 0;
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t.tv_usec = 0;
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if (ioctl (info -> rfdesc, NIOCSTIME, &t) < 0)
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log_fatal ("Can't set chunk timeout: %m");
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#endif
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/* Ask for no header... */
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x = 0;
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if (ioctl (info -> rfdesc, NIOCSFLAGS, &x) < 0)
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log_fatal ("Can't set NIT flags on %s: %m", info -> name);
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/* Set up the NIT filter program. */
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/* XXX Unlike the BPF filter program, this one won't work if the
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XXX IP packet is fragmented or if there are options on the IP
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XXX header. */
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pf.Pf_Priority = 0;
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pf.Pf_FilterLen = 0;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 6;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (ETHERTYPE_IP);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (0xFF);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 18;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = local_port;
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/* Install the filter... */
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sio.ic_cmd = NIOCSETF;
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sio.ic_len = sizeof pf;
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sio.ic_dp = (char *)&pf;
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sio.ic_timout = INFTIM;
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if (ioctl (info -> rfdesc, I_STR, &sio) < 0)
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log_fatal ("Can't set NIT filter on %s: %m", info -> name);
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if (!quiet_interface_discovery)
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log_info ("Listening on NIT/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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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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void if_deregister_receive (info)
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struct interface_info *info;
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{
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/* If we're using the nit API for sending and receiving,
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we don't need to register this interface twice. */
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close (info -> rfdesc);
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info -> rfdesc = -1;
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if (!quiet_interface_discovery)
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log_info ("Disabling input on NIT/%s%s%s",
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print_hw_addr (info -> hw_address.hbuf [0],
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info -> hw_address.hlen - 1,
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&info -> hw_address.hbuf [1]),
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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_NIT_RECEIVE */
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#ifdef USE_NIT_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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unsigned hbufp, ibufp;
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double hh [16];
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double ih [1536 / sizeof (double)];
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unsigned char *buf = (unsigned char *)ih;
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struct sockaddr *junk;
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struct strbuf ctl, data;
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struct sockaddr_in foo;
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int result;
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if (!strcmp (interface -> name, "fallback"))
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return send_fallback (interface, packet, raw,
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len, from, to, hto);
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/* Start with the sockaddr struct... */
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junk = (struct sockaddr *)&hh [0];
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hbufp = (((unsigned char *)&junk -> sa_data [0]) -
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(unsigned char *)&hh[0]);
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ibufp = 0;
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/* Assemble the headers... */
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assemble_hw_header (interface, (unsigned char *)junk, &hbufp, hto);
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assemble_udp_ip_header (interface, buf, &ibufp,
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from.s_addr, to -> sin_addr.s_addr,
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to -> sin_port, (unsigned char *)raw, len);
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/* Copy the data into the buffer (yuk). */
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memcpy (buf + ibufp, raw, len);
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/* Set up the sockaddr structure... */
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#if USE_SIN_LEN
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junk -> sa_len = hbufp - 2; /* XXX */
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#endif
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junk -> sa_family = AF_UNSPEC;
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/* Set up the msg_buf structure... */
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ctl.buf = (char *)&hh [0];
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ctl.maxlen = ctl.len = hbufp;
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data.buf = (char *)&ih [0];
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data.maxlen = data.len = ibufp + len;
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result = putmsg (interface -> wfdesc, &ctl, &data, 0);
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if (result < 0)
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log_error ("send_packet: %m");
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return result;
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}
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#endif /* USE_NIT_SEND */
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#ifdef USE_NIT_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 nread;
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int length = 0;
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int offset = 0;
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unsigned char ibuf [1536];
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int bufix = 0;
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length = read (interface -> rfdesc, ibuf, sizeof ibuf);
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if (length <= 0)
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return length;
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/* Decode the physical header... */
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offset = decode_hw_header (interface, ibuf, bufix, hfrom);
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/* If a physical layer checksum failed (dunno of any
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physical layer that supports this, but WTH), skip this
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packet. */
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if (offset < 0) {
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return 0;
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}
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bufix += offset;
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length -= offset;
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/* Decode the IP and UDP headers... */
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offset = decode_udp_ip_header (interface, ibuf, bufix,
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from, length);
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/* If the IP or UDP checksum was bad, skip the packet... */
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if (offset < 0)
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return 0;
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bufix += offset;
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length -= offset;
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/* Copy out the data in the packet... */
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memcpy (buf, &ibuf [bufix], length);
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return length;
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}
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int can_unicast_without_arp (ip)
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struct interface_info *ip;
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{
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return 1;
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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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return 1;
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}
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int supports_multiple_interfaces (ip)
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struct interface_info *ip;
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{
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return 1;
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}
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void maybe_setup_fallback ()
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{
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isc_result_t status;
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struct interface_info *fbi = (struct interface_info *)0;
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if (setup_fallback (&fbi, MDL)) {
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if_register_fallback (fbi);
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status = omapi_register_io_object ((omapi_object_t *)fbi,
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if_readsocket, 0,
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fallback_discard, 0, 0);
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if (status != ISC_R_SUCCESS)
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log_fatal ("Can't register I/O handle for %s: %s",
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fbi -> name, isc_result_totext (status));
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interface_dereference (&fbi, MDL);
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}
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}
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#endif
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