[thirdparty/dhcp.git] / common / bpf.c

/* bpf.c

   BPF socket interface code, originally contributed by Archie Cobbs. */

/*
 * Copyright (c) 1996-2000 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 was contributed to the Internet Software Consortium
 * by Archie Cobbs, and is now maintained by Ted Lemon in cooperation
 * with 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''.
 *
 * Patches for FDDI support on Digital Unix were written by Bill
 * Stapleton, and maintained for a while by Mike Meredith before he
 * managed to get me to integrate them.
 */

#ifndef lint
static char copyright[] =
"$Id: bpf.c,v 1.42 2000/09/01 23:03:31 mellon Exp $ Copyright (c) 1995-2000 The Internet Software Consortium.  All rights reserved.\n";
#endif /* not lint */

#include "dhcpd.h"
#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)	\
				|| defined (USE_LPF_RECEIVE)
# if defined (USE_LPF_RECEIVE)
#  include <asm/types.h>
#  include <linux/filter.h>
#  define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
# else
#  include <sys/ioctl.h>
#  include <sys/uio.h>
#  include <net/bpf.h>
#  if defined (NEED_OSF_PFILT_HACKS)
#   include <net/pfilt.h>
#  endif
# endif

#include <netinet/in_systm.h>
#include "includes/netinet/ip.h"
#include "includes/netinet/udp.h"
#include "includes/netinet/if_ether.h"
#endif

/* Reinitializes the specified interface after an address change.   This
   is not required for packet-filter APIs. */

#ifdef USE_BPF_SEND
void if_reinitialize_send (info)
	struct interface_info *info;
{
}
#endif

#ifdef USE_BPF_RECEIVE
void if_reinitialize_receive (info)
	struct interface_info *info;
{
}
#endif

/* Called by get_interface_list for each interface that's discovered.
   Opens a packet filter for each interface and adds it to the select
   mask. */

#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)
int if_register_bpf (info)
	struct interface_info *info;
{
	int sock;
	char filename[50];
	int b;

	/* Open a BPF device */
	for (b = 0; 1; b++) {
#ifndef NO_SNPRINTF
		snprintf(filename, sizeof(filename), BPF_FORMAT, b);
#else
		sprintf(filename, BPF_FORMAT, b);
#endif
		sock = open (filename, O_RDWR, 0);
		if (sock < 0) {
			if (errno == EBUSY) {
				continue;
			} else {
				if (!b)
					log_fatal ("No bpf devices.%s%s%s",
					       "   Please read the README",
					       " section for your operating",
					       " system.");
				log_fatal ("Can't find free bpf: %m");
			}
		} else {
			break;
		}
	}

	/* Set the BPF device to point at this interface. */
	if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
		log_fatal ("Can't attach interface %s to bpf device %s: %m",
		       info -> name, filename);

	return sock;
}
#endif /* USE_BPF_SEND || USE_BPF_RECEIVE */

#ifdef USE_BPF_SEND
void if_register_send (info)
	struct interface_info *info;
{
	/* If we're using the bpf API for sending and receiving,
	   we don't need to register this interface twice. */
#ifndef USE_BPF_RECEIVE
	info -> wfdesc = if_register_bpf (info, interface);
#else
	info -> wfdesc = info -> rfdesc;
#endif
	if (!quiet_interface_discovery)
		log_info ("Sending on   BPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.hbuf [0],
				     info -> hw_address.hlen - 1,
				     &info -> hw_address.hbuf [1]),
		      (info -> shared_network ? "/" : ""),
		      (info -> shared_network ?
		       info -> shared_network -> name : ""));
}

void if_deregister_send (info)
	struct interface_info *info;
{
	/* If we're using the bpf API for sending and receiving,
	   we don't need to register this interface twice. */
#ifndef USE_BPF_RECEIVE
	close (info -> wfdesc);
#endif
	info -> wfdesc = -1;

	if (!quiet_interface_discovery)
		log_info ("Disabling output on BPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.hbuf [0],
				     info -> hw_address.hlen - 1,
				     &info -> hw_address.hbuf [1]),
		      (info -> shared_network ? "/" : ""),
		      (info -> shared_network ?
		       info -> shared_network -> name : ""));
}
#endif /* USE_BPF_SEND */

#if defined (USE_BPF_RECEIVE) || defined (USE_LPF_RECEIVE)
/* Packet filter program...
   XXX Changes to the filter program may require changes to the constant
   offsets used in if_register_send to patch the BPF program! XXX */

struct bpf_insn dhcp_bpf_filter [] = {
	/* Make sure this is an IP packet... */
	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),

	/* Make sure it's a UDP packet... */
	BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),

	/* Make sure this isn't a fragment... */
	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
	BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),

	/* Get the IP header length... */
	BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),

	/* Make sure it's to the right port... */
	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1),             /* patch */

	/* If we passed all the tests, ask for the whole packet. */
	BPF_STMT(BPF_RET+BPF_K, (u_int)-1),

	/* Otherwise, drop it. */
	BPF_STMT(BPF_RET+BPF_K, 0),
};

struct bpf_insn *bpf_fddi_filter;

int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
struct bpf_insn dhcp_bpf_tr_filter [] = {
        /* accept all token ring packets due to variable length header */
        /* if we want to get clever, insert the program here */

	/* If we passed all the tests, ask for the whole packet. */
	BPF_STMT(BPF_RET+BPF_K, (u_int)-1),

	/* Otherwise, drop it. */
	BPF_STMT(BPF_RET+BPF_K, 0),
};

int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
			      sizeof (struct bpf_insn));
#endif

#if defined (USE_BPF_RECEIVE)
void if_register_receive (info)
	struct interface_info *info;
{
	int flag = 1;
	struct bpf_version v;
	u_int32_t addr;
	struct bpf_program p;
	u_int32_t bits;
#ifdef DEC_FDDI
	int link_layer;
#endif /* DEC_FDDI */

	/* Open a BPF device and hang it on this interface... */
	info -> rfdesc = if_register_bpf (info);

	/* Make sure the BPF version is in range... */
	if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
		log_fatal ("Can't get BPF version: %m");

	if (v.bv_major != BPF_MAJOR_VERSION ||
	    v.bv_minor < BPF_MINOR_VERSION)
		log_fatal ("Kernel BPF version out of range - recompile dhcpd!");

	/* Set immediate mode so that reads return as soon as a packet
	   comes in, rather than waiting for the input buffer to fill with
	   packets. */
	if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
		log_fatal ("Can't set immediate mode on bpf device: %m");

#ifdef NEED_OSF_PFILT_HACKS
	/* Allow the copyall flag to be set... */
	if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
		log_fatal ("Can't set ALLOWCOPYALL: %m");

	/* Clear all the packet filter mode bits first... */
	bits = 0;
	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
		log_fatal ("Can't clear pfilt bits: %m");

	/* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
	bits = ENBATCH | ENCOPYALL | ENBPFHDR;
	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
		log_fatal ("Can't set ENBATCH|ENCOPYALL|ENBPFHDR: %m");
#endif
	/* Get the required BPF buffer length from the kernel. */
	if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
		log_fatal ("Can't get bpf buffer length: %m");
	info -> rbuf = dmalloc (info -> rbuf_max, MDL);
	if (!info -> rbuf)
		log_fatal ("Can't allocate %d bytes for bpf input buffer.",
			   info -> rbuf_max);
	info -> rbuf_offset = 0;
	info -> rbuf_len = 0;

	/* Set up the bpf filter program structure. */
	p.bf_len = dhcp_bpf_filter_len;

#ifdef DEC_FDDI
	/* See if this is an FDDI interface, flag it for later. */
	if (ioctl(info -> rfdesc, BIOCGDLT, &link_layer) >= 0 &&
	    link_layer == DLT_FDDI) {
		if (!bpf_fddi_filter) {
			bpf_fddi_filter = dmalloc (sizeof bpf_fddi_filter,
						    MDL);
			if (!bpf_fddi_filter)
				log_fatal ("No memory for FDDI filter.");
			memcpy (bpf_fddi_filter,
				dhcp_bpf_filter, sizeof dhcp_bpf_filter);
			/* Patch the BPF program to account for the difference
			   in length between ethernet headers (14), FDDI and
			   802.2 headers (16 +8=24, +10).
			   XXX changes to filter program may require changes to
			   XXX the insn number(s) used below! */
			bpf_fddi_filter[0].k += 10;
			bpf_fddi_filter[2].k += 10;
			bpf_fddi_filter[4].k += 10;
			bpf_fddi_filter[6].k += 10;
			bpf_fddi_filter[7].k += 10;
		}
		p.bf_insns = bpf_fddi_filter;
	} else
#endif /* DEC_FDDI */
	p.bf_insns = dhcp_bpf_filter;

        /* Patch the server port into the BPF  program...
	   XXX changes to filter program may require changes
	   to the insn number(s) used below! XXX */
	dhcp_bpf_filter [8].k = ntohs (local_port);

	if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
		log_fatal ("Can't install packet filter program: %m");
	if (!quiet_interface_discovery)
		log_info ("Listening on BPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.hbuf [0],
				     info -> hw_address.hlen - 1,
				     &info -> hw_address.hbuf [1]),
		      (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 BPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.hbuf [0],
				     info -> hw_address.hlen - 1,
				     &info -> hw_address.hbuf [1]),
		      (info -> shared_network ? "/" : ""),
		      (info -> shared_network ?
		       info -> shared_network -> name : ""));
}
#endif /* USE_BPF_RECEIVE */

#ifdef USE_BPF_SEND
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;
{
	unsigned hbufp = 0, ibufp = 0;
	double hw [4];
	double ip [32];
	struct iovec iov [3];
	int result;
	int fudge;

	if (!strcmp (interface -> name, "fallback"))
		return send_fallback (interface, packet, raw,
				      len, from, to, hto);

	/* Assemble the headers... */
	assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
	assemble_udp_ip_header (interface,
				(unsigned char *)ip, &ibufp, from.s_addr,
				to -> sin_addr.s_addr, to -> sin_port,
				(unsigned char *)raw, len);

	/* Fire it off */
	iov [0].iov_base = ((char *)hw);
	iov [0].iov_len = hbufp;
	iov [1].iov_base = ((char *)ip);
	iov [1].iov_len = ibufp;
	iov [2].iov_base = (char *)raw;
	iov [2].iov_len = len;

	result = writev(interface -> wfdesc, iov, 3);
	if (result < 0)
		log_error ("send_packet: %m");
	return result;
}
#endif /* USE_BPF_SEND */

#ifdef USE_BPF_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;
{
	int length = 0;
	int offset = 0;
	struct bpf_hdr hdr;

	/* All this complexity is because BPF doesn't guarantee
	   that only one packet will be returned at a time.   We're
	   getting what we deserve, though - this is a terrible abuse
	   of the BPF interface.   Sigh. */

	/* Process packets until we get one we can return or until we've
	   done a read and gotten nothing we can return... */

	do {
		/* If the buffer is empty, fill it. */
		if (interface -> rbuf_offset == interface -> rbuf_len) {
			length = read (interface -> rfdesc,
				       interface -> rbuf,
				       interface -> rbuf_max);
			if (length <= 0)
				return length;
			interface -> rbuf_offset = 0;
			interface -> rbuf_len = length;
		}

		/* If there isn't room for a whole bpf header, something went
		   wrong, but we'll ignore it and hope it goes away... XXX */
		if (interface -> rbuf_len -
		    interface -> rbuf_offset < sizeof hdr) {
			interface -> rbuf_offset = interface -> rbuf_len;
			continue;
		}

		/* Copy out a bpf header... */
		memcpy (&hdr, &interface -> rbuf [interface -> rbuf_offset],
			sizeof hdr);

		/* If the bpf header plus data doesn't fit in what's left
		   of the buffer, stick head in sand yet again... */
		if (interface -> rbuf_offset +
		    hdr.bh_hdrlen + hdr.bh_caplen > interface -> rbuf_len) {
			interface -> rbuf_offset = interface -> rbuf_len;
			continue;
		}

		/* If the captured data wasn't the whole packet, or if
		   the packet won't fit in the input buffer, all we
		   can do is drop it. */
		if (hdr.bh_caplen != hdr.bh_datalen) {
			interface -> rbuf_offset +=
				hdr.bh_hdrlen = hdr.bh_caplen;
			continue;
		}

		/* Skip over the BPF header... */
		interface -> rbuf_offset += hdr.bh_hdrlen;

		/* Decode the physical header... */
		offset = decode_hw_header (interface,
					   interface -> rbuf,
					   interface -> rbuf_offset,
					   hfrom);

		/* If a physical layer checksum failed (dunno of any
		   physical layer that supports this, but WTH), skip this
		   packet. */
		if (offset < 0) {
			interface -> rbuf_offset += hdr.bh_caplen;
			continue;
		}
		interface -> rbuf_offset += offset;
		hdr.bh_caplen -= offset;

		/* Decode the IP and UDP headers... */
		offset = decode_udp_ip_header (interface,
					       interface -> rbuf,
					       interface -> rbuf_offset,
					       from,
					       (unsigned char *)0,
					       hdr.bh_caplen);

		/* If the IP or UDP checksum was bad, skip the packet... */
		if (offset < 0) {
			interface -> rbuf_offset += hdr.bh_caplen;
			continue;
		}
		interface -> rbuf_offset += offset;
		hdr.bh_caplen -= offset;

		/* If there's not enough room to stash the packet data,
		   we have to skip it (this shouldn't happen in real
		   life, though). */
		if (hdr.bh_caplen > len) {
			interface -> rbuf_offset += hdr.bh_caplen;
			continue;
		}

		/* Copy out the data in the packet... */
		memcpy (buf, interface -> rbuf + interface -> rbuf_offset,
			hdr.bh_caplen);
		interface -> rbuf_offset += hdr.bh_caplen;
		return hdr.bh_caplen;
	} while (!length);
	return 0;
}

int can_unicast_without_arp (ip)
	struct interface_info *ip;
{
	return 1;
}

int can_receive_unicast_unconfigured (ip)
	struct interface_info *ip;
{
	return 1;
}

int supports_multiple_interfaces (ip)
	struct interface_info *ip;
{
	return 1;
}

void maybe_setup_fallback ()
{
	isc_result_t status;
	struct interface_info *fbi = (struct interface_info *)0;
	if (setup_fallback (&fbi, MDL)) {
		if_register_fallback (fbi);
		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));
		interface_dereference (&fbi, MDL);
	}
}
#endif
Commit	Line	Data
8cb33098 TL	1	/* bpf.c
	2
	3	BPF socket interface code, originally contributed by Archie Cobbs. */
	4
	5	/*
49733f31 TL	6	* Copyright (c) 1996-2000 Internet Software Consortium.
49733f31 TL	7	* All rights reserved.
8cb33098	8	*
49733f31 TL	9	* Redistribution and use in source and binary forms, with or without
	10	* modification, are permitted provided that the following conditions
	11	* are met:
8cb33098	12	*
49733f31 TL	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
	18	* 3. Neither the name of The Internet Software Consortium nor the names
	19	* of its contributors may be used to endorse or promote products derived
	20	* from this software without specific prior written permission.
8cb33098	21	*
49733f31 TL	22	* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
	23	* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
	24	* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	25	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	26	* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
	27	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	28	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	29	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
	30	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	31	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	32	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	33	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*
0e944b06 TL	36	* This software was contributed to the Internet Software Consortium
	37	* by Archie Cobbs, and is now maintained by Ted Lemon in cooperation
	38	* with Nominum, Inc. To learn more about the Internet Software
	39	* Consortium, see ``http://www.isc.org/''. To learn more about Vixie
	40	* Enterprises, see ``http://www.vix.com''. To learn more about
	41	* Nominum, Inc., see ``http://www.nominum.com''.
201601d5 TL	42	*
	43	* Patches for FDDI support on Digital Unix were written by Bill
	44	* Stapleton, and maintained for a while by Mike Meredith before he
	45	* managed to get me to integrate them.
8cb33098 TL	46	*/
	47
	48	#ifndef lint
	49	static char copyright[] =
5cefe5e5	50	"$Id: bpf.c,v 1.42 2000/09/01 23:03:31 mellon Exp $ Copyright (c) 1995-2000 The Internet Software Consortium. All rights reserved.\n";
8cb33098 TL	51	#endif /* not lint */
	52
	53	#include "dhcpd.h"
d2bc90bd TL	54	#if defined (USE_BPF_SEND) \|\| defined (USE_BPF_RECEIVE) \
	55	\|\| defined (USE_LPF_RECEIVE)
	56	# if defined (USE_LPF_RECEIVE)
	57	# include <asm/types.h>
	58	# include <linux/filter.h>
	59	# define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
	60	# else
	61	# include <sys/ioctl.h>
	62	# include <sys/uio.h>
	63	# include <net/bpf.h>
	64	# if defined (NEED_OSF_PFILT_HACKS)
	65	# include <net/pfilt.h>
	66	# endif
	67	# endif
8cb33098	68
8cb33098	69	#include <netinet/in_systm.h>
c41e81e4 TL	70	#include "includes/netinet/ip.h"
	71	#include "includes/netinet/udp.h"
	72	#include "includes/netinet/if_ether.h"
d2bc90bd	73	#endif
8cb33098	74
c3585217 TL	75	/* Reinitializes the specified interface after an address change. This
	76	is not required for packet-filter APIs. */
	77
	78	#ifdef USE_BPF_SEND
	79	void if_reinitialize_send (info)
	80	struct interface_info *info;
	81	{
	82	}
	83	#endif
	84
	85	#ifdef USE_BPF_RECEIVE
	86	void if_reinitialize_receive (info)
	87	struct interface_info *info;
	88	{
	89	}
	90	#endif
	91
8cb33098 TL	92	/* Called by get_interface_list for each interface that's discovered.
	93	Opens a packet filter for each interface and adds it to the select
	94	mask. */
	95
d2bc90bd	96	#if defined (USE_BPF_SEND) \|\| defined (USE_BPF_RECEIVE)
c3585217	97	int if_register_bpf (info)
045820ee	98	struct interface_info *info;
8cb33098	99	{
045820ee	100	int sock;
8cb33098	101	char filename[50];
045820ee	102	int b;
8cb33098 TL	103
	104	/* Open a BPF device */
	105	for (b = 0; 1; b++) {
d64c8816	106	#ifndef NO_SNPRINTF
019f8a12	107	snprintf(filename, sizeof(filename), BPF_FORMAT, b);
d64c8816	108	#else
019f8a12	109	sprintf(filename, BPF_FORMAT, b);
d64c8816	110	#endif
045820ee TL	111	sock = open (filename, O_RDWR, 0);
045820ee TL	112	if (sock < 0) {
8cb33098 TL	113	if (errno == EBUSY) {
	114	continue;
	115	} else {
d2bc90bd	116	if (!b)
8ae2d595	117	log_fatal ("No bpf devices.%s%s%s",
d2bc90bd TL	118	" Please read the README",
	119	" section for your operating",
	120	" system.");
8ae2d595	121	log_fatal ("Can't find free bpf: %m");
8cb33098 TL	122	}
	123	} else {
	124	break;
	125	}
	126	}
	127
	128	/* Set the BPF device to point at this interface. */
c3585217	129	if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
8ae2d595	130	log_fatal ("Can't attach interface %s to bpf device %s: %m",
c255efc9	131	info -> name, filename);
045820ee TL	132
	133	return sock;
	134	}
	135	#endif /* USE_BPF_SEND \|\| USE_BPF_RECEIVE */
	136
	137	#ifdef USE_BPF_SEND
c3585217	138	void if_register_send (info)
045820ee	139	struct interface_info *info;
045820ee TL	140	{
	141	/* If we're using the bpf API for sending and receiving,
	142	we don't need to register this interface twice. */
	143	#ifndef USE_BPF_RECEIVE
	144	info -> wfdesc = if_register_bpf (info, interface);
	145	#else
	146	info -> wfdesc = info -> rfdesc;
	147	#endif
3648a2a1	148	if (!quiet_interface_discovery)
74f45f96	149	log_info ("Sending on BPF/%s/%s%s%s",
3648a2a1	150	info -> name,
31730f17 TL	151	print_hw_addr (info -> hw_address.hbuf [0],
	152	info -> hw_address.hlen - 1,
	153	&info -> hw_address.hbuf [1]),
74f45f96	154	(info -> shared_network ? "/" : ""),
3648a2a1	155	(info -> shared_network ?
74f45f96	156	info -> shared_network -> name : ""));
8cb33098	157	}
7203e8ee TL	158
	159	void if_deregister_send (info)
	160	struct interface_info *info;
	161	{
	162	/* If we're using the bpf API for sending and receiving,
	163	we don't need to register this interface twice. */
	164	#ifndef USE_BPF_RECEIVE
	165	close (info -> wfdesc);
	166	#endif
	167	info -> wfdesc = -1;
	168
	169	if (!quiet_interface_discovery)
	170	log_info ("Disabling output on BPF/%s/%s%s%s",
	171	info -> name,
	172	print_hw_addr (info -> hw_address.hbuf [0],
	173	info -> hw_address.hlen - 1,
	174	&info -> hw_address.hbuf [1]),
	175	(info -> shared_network ? "/" : ""),
	176	(info -> shared_network ?
	177	info -> shared_network -> name : ""));
	178	}
045820ee TL	179	#endif /* USE_BPF_SEND */
045820ee TL	180
d2bc90bd	181	#if defined (USE_BPF_RECEIVE) \|\| defined (USE_LPF_RECEIVE)
045820ee TL	182	/* Packet filter program...
	183	XXX Changes to the filter program may require changes to the constant
	184	offsets used in if_register_send to patch the BPF program! XXX */
	185
d2bc90bd	186	struct bpf_insn dhcp_bpf_filter [] = {
045820ee TL	187	/* Make sure this is an IP packet... */
045820ee TL	188	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
f1c1b296	189	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
045820ee TL	190
	191	/* Make sure it's a UDP packet... */
	192	BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
f1c1b296	193	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
045820ee TL	194
	195	/* Make sure this isn't a fragment... */
	196	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
f1c1b296	197	BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
045820ee TL	198
	199	/* Get the IP header length... */
	200	BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
	201
	202	/* Make sure it's to the right port... */
	203	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
f1c1b296	204	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1), /* patch */
8cb33098	205
045820ee TL	206	/* If we passed all the tests, ask for the whole packet. */
	207	BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
	208
	209	/* Otherwise, drop it. */
	210	BPF_STMT(BPF_RET+BPF_K, 0),
	211	};
	212
95e58554 TL	213	struct bpf_insn *bpf_fddi_filter;
95e58554 TL	214
d2bc90bd	215	int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
7d29d66d TL	216	struct bpf_insn dhcp_bpf_tr_filter [] = {
	217	/* accept all token ring packets due to variable length header */
	218	/* if we want to get clever, insert the program here */
	219
	220	/* If we passed all the tests, ask for the whole packet. */
	221	BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
	222
	223	/* Otherwise, drop it. */
	224	BPF_STMT(BPF_RET+BPF_K, 0),
	225	};
	226
	227	int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
	228	sizeof (struct bpf_insn));
d2bc90bd TL	229	#endif
	230
	231	#if defined (USE_BPF_RECEIVE)
c3585217	232	void if_register_receive (info)
045820ee	233	struct interface_info *info;
045820ee TL	234	{
	235	int flag = 1;
	236	struct bpf_version v;
	237	u_int32_t addr;
	238	struct bpf_program p;
019f8a12	239	u_int32_t bits;
95e58554 TL	240	#ifdef DEC_FDDI
	241	int link_layer;
	242	#endif /* DEC_FDDI */
045820ee TL	243
045820ee TL	244	/* Open a BPF device and hang it on this interface... */
c3585217	245	info -> rfdesc = if_register_bpf (info);
045820ee TL	246
	247	/* Make sure the BPF version is in range... */
	248	if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
8ae2d595	249	log_fatal ("Can't get BPF version: %m");
045820ee TL	250
	251	if (v.bv_major != BPF_MAJOR_VERSION \|\|
	252	v.bv_minor < BPF_MINOR_VERSION)
8ae2d595	253	log_fatal ("Kernel BPF version out of range - recompile dhcpd!");
045820ee TL	254
	255	/* Set immediate mode so that reads return as soon as a packet
	256	comes in, rather than waiting for the input buffer to fill with
	257	packets. */
	258	if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
8ae2d595	259	log_fatal ("Can't set immediate mode on bpf device: %m");
045820ee	260
019f8a12 TL	261	#ifdef NEED_OSF_PFILT_HACKS
	262	/* Allow the copyall flag to be set... */
	263	if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
8ae2d595	264	log_fatal ("Can't set ALLOWCOPYALL: %m");
019f8a12 TL	265
	266	/* Clear all the packet filter mode bits first... */
	267	bits = 0;
	268	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
8ae2d595	269	log_fatal ("Can't clear pfilt bits: %m");
019f8a12 TL	270
	271	/* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
	272	bits = ENBATCH \| ENCOPYALL \| ENBPFHDR;
	273	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
8ae2d595	274	log_fatal ("Can't set ENBATCH\|ENCOPYALL\|ENBPFHDR: %m");
019f8a12	275	#endif
045820ee TL	276	/* Get the required BPF buffer length from the kernel. */
045820ee TL	277	if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
8ae2d595	278	log_fatal ("Can't get bpf buffer length: %m");
4bd8800e	279	info -> rbuf = dmalloc (info -> rbuf_max, MDL);
045820ee	280	if (!info -> rbuf)
ab58ff49 TL	281	log_fatal ("Can't allocate %d bytes for bpf input buffer.",
ab58ff49 TL	282	info -> rbuf_max);
045820ee TL	283	info -> rbuf_offset = 0;
	284	info -> rbuf_len = 0;
	285
045820ee	286	/* Set up the bpf filter program structure. */
d2bc90bd	287	p.bf_len = dhcp_bpf_filter_len;
95e58554 TL	288
	289	#ifdef DEC_FDDI
	290	/* See if this is an FDDI interface, flag it for later. */
	291	if (ioctl(info -> rfdesc, BIOCGDLT, &link_layer) >= 0 &&
	292	link_layer == DLT_FDDI) {
201601d5 TL	293	if (!bpf_fddi_filter) {
201601d5 TL	294	bpf_fddi_filter = dmalloc (sizeof bpf_fddi_filter,
95e58554	295	MDL);
201601d5	296	if (!bpf_fddi_filter)
95e58554	297	log_fatal ("No memory for FDDI filter.");
201601d5	298	memcpy (bpf_fddi_filter,
95e58554 TL	299	dhcp_bpf_filter, sizeof dhcp_bpf_filter);
	300	/* Patch the BPF program to account for the difference
	301	in length between ethernet headers (14), FDDI and
	302	802.2 headers (16 +8=24, +10).
	303	XXX changes to filter program may require changes to
	304	XXX the insn number(s) used below! */
201601d5 TL	305	bpf_fddi_filter[0].k += 10;
	306	bpf_fddi_filter[2].k += 10;
	307	bpf_fddi_filter[4].k += 10;
	308	bpf_fddi_filter[6].k += 10;
	309	bpf_fddi_filter[7].k += 10;
95e58554	310	}
201601d5	311	p.bf_insns = bpf_fddi_filter;
95e58554 TL	312	} else
95e58554 TL	313	#endif /* DEC_FDDI */
d2bc90bd	314	p.bf_insns = dhcp_bpf_filter;
045820ee	315
229b6208 TL	316	/* Patch the server port into the BPF program...
	317	XXX changes to filter program may require changes
	318	to the insn number(s) used below! XXX */
d2bc90bd	319	dhcp_bpf_filter [8].k = ntohs (local_port);
229b6208	320
045820ee	321	if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
8ae2d595	322	log_fatal ("Can't install packet filter program: %m");
3648a2a1	323	if (!quiet_interface_discovery)
74f45f96	324	log_info ("Listening on BPF/%s/%s%s%s",
3648a2a1	325	info -> name,
31730f17	326	print_hw_addr (info -> hw_address.hbuf [0],
7203e8ee TL	327	info -> hw_address.hlen - 1,
	328	&info -> hw_address.hbuf [1]),
	329	(info -> shared_network ? "/" : ""),
	330	(info -> shared_network ?
	331	info -> shared_network -> name : ""));
	332	}
	333
	334	void if_deregister_receive (info)
	335	struct interface_info *info;
	336	{
	337	close (info -> rfdesc);
	338	info -> rfdesc = -1;
	339
	340	if (!quiet_interface_discovery)
	341	log_info ("Disabling input on BPF/%s/%s%s%s",
	342	info -> name,
	343	print_hw_addr (info -> hw_address.hbuf [0],
31730f17 TL	344	info -> hw_address.hlen - 1,
31730f17 TL	345	&info -> hw_address.hbuf [1]),
74f45f96	346	(info -> shared_network ? "/" : ""),
3648a2a1	347	(info -> shared_network ?
74f45f96	348	info -> shared_network -> name : ""));
045820ee TL	349	}
	350	#endif /* USE_BPF_RECEIVE */
	351
	352	#ifdef USE_BPF_SEND
4595a58c	353	ssize_t send_packet (interface, packet, raw, len, from, to, hto)
045820ee TL	354	struct interface_info *interface;
	355	struct packet *packet;
	356	struct dhcp_packet *raw;
	357	size_t len;
f1c1b296	358	struct in_addr from;
045820ee TL	359	struct sockaddr_in *to;
	360	struct hardware *hto;
	361	{
6ceb9118 TL	362	unsigned hbufp = 0, ibufp = 0;
	363	double hw [4];
	364	double ip [32];
	365	struct iovec iov [3];
74f45f96	366	int result;
6ceb9118	367	int fudge;
045820ee	368
d2bc90bd TL	369	if (!strcmp (interface -> name, "fallback"))
	370	return send_fallback (interface, packet, raw,
	371	len, from, to, hto);
	372
045820ee	373	/* Assemble the headers... */
6ceb9118 TL	374	assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
	375	assemble_udp_ip_header (interface,
	376	(unsigned char *)ip, &ibufp, from.s_addr,
045820ee TL	377	to -> sin_addr.s_addr, to -> sin_port,
	378	(unsigned char *)raw, len);
	379
	380	/* Fire it off */
6ceb9118 TL	381	iov [0].iov_base = ((char *)hw);
	382	iov [0].iov_len = hbufp;
	383	iov [1].iov_base = ((char *)ip);
	384	iov [1].iov_len = ibufp;
	385	iov [2].iov_base = (char *)raw;
	386	iov [2].iov_len = len;
	387
	388	result = writev(interface -> wfdesc, iov, 3);
74f45f96	389	if (result < 0)
c5b0f529	390	log_error ("send_packet: %m");
74f45f96	391	return result;
045820ee TL	392	}
	393	#endif /* USE_BPF_SEND */
	394
	395	#ifdef USE_BPF_RECEIVE
4595a58c	396	ssize_t receive_packet (interface, buf, len, from, hfrom)
045820ee TL	397	struct interface_info *interface;
	398	unsigned char *buf;
	399	size_t len;
	400	struct sockaddr_in *from;
	401	struct hardware *hfrom;
	402	{
	403	int length = 0;
	404	int offset = 0;
	405	struct bpf_hdr hdr;
	406
	407	/* All this complexity is because BPF doesn't guarantee
	408	that only one packet will be returned at a time. We're
	409	getting what we deserve, though - this is a terrible abuse
	410	of the BPF interface. Sigh. */
	411
	412	/* Process packets until we get one we can return or until we've
	413	done a read and gotten nothing we can return... */
	414
	415	do {
	416	/* If the buffer is empty, fill it. */
	417	if (interface -> rbuf_offset == interface -> rbuf_len) {
	418	length = read (interface -> rfdesc,
	419	interface -> rbuf,
	420	interface -> rbuf_max);
	421	if (length <= 0)
	422	return length;
	423	interface -> rbuf_offset = 0;
	424	interface -> rbuf_len = length;
	425	}
	426
	427	/* If there isn't room for a whole bpf header, something went
	428	wrong, but we'll ignore it and hope it goes away... XXX */
	429	if (interface -> rbuf_len -
	430	interface -> rbuf_offset < sizeof hdr) {
	431	interface -> rbuf_offset = interface -> rbuf_len;
	432	continue;
	433	}
	434
	435	/* Copy out a bpf header... */
	436	memcpy (&hdr, &interface -> rbuf [interface -> rbuf_offset],
	437	sizeof hdr);
	438
	439	/* If the bpf header plus data doesn't fit in what's left
	440	of the buffer, stick head in sand yet again... */
	441	if (interface -> rbuf_offset +
	442	hdr.bh_hdrlen + hdr.bh_caplen > interface -> rbuf_len) {
	443	interface -> rbuf_offset = interface -> rbuf_len;
	444	continue;
	445	}
	446
	447	/* If the captured data wasn't the whole packet, or if
	448	the packet won't fit in the input buffer, all we
	449	can do is drop it. */
	450	if (hdr.bh_caplen != hdr.bh_datalen) {
	451	interface -> rbuf_offset +=
	452	hdr.bh_hdrlen = hdr.bh_caplen;
	453	continue;
	454	}
	455
	456	/* Skip over the BPF header... */
	457	interface -> rbuf_offset += hdr.bh_hdrlen;
	458
	459	/* Decode the physical header... */
	460	offset = decode_hw_header (interface,
461	interface -> rbuf,
462	interface -> rbuf_offset,
463	hfrom);
464
465	/* If a physical layer checksum failed (dunno of any
466	physical layer that supports this, but WTH), skip this
467	packet. */
468	if (offset < 0) {
469	interface -> rbuf_offset += hdr.bh_caplen;
470	continue;
471	}
472	interface -> rbuf_offset += offset;
473	hdr.bh_caplen -= offset;
474
475	/* Decode the IP and UDP headers... */
476	offset = decode_udp_ip_header (interface,
477	interface -> rbuf,
478	interface -> rbuf_offset,
479	from,
480	(unsigned char *)0,
481	hdr.bh_caplen);
482
483	/* If the IP or UDP checksum was bad, skip the packet... */
484	if (offset < 0) {
485	interface -> rbuf_offset += hdr.bh_caplen;
486	continue;
487	}
488	interface -> rbuf_offset += offset;
489	hdr.bh_caplen -= offset;
490
491	/* If there's not enough room to stash the packet data,
492	we have to skip it (this shouldn't happen in real
493	life, though). */
494	if (hdr.bh_caplen > len) {
495	interface -> rbuf_offset += hdr.bh_caplen;
496	continue;
497	}
498
499	/* Copy out the data in the packet... */
500	memcpy (buf, interface -> rbuf + interface -> rbuf_offset,
501	hdr.bh_caplen);
502	interface -> rbuf_offset += hdr.bh_caplen;
503	return hdr.bh_caplen;
504	} while (!length);
505	return 0;
506	}
d2bc90bd	507
21d21e91 TL	508	int can_unicast_without_arp (ip)
21d21e91 TL	509	struct interface_info *ip;
d2bc90bd TL	510	{
	511	return 1;
	512	}
	513
21d21e91 TL	514	int can_receive_unicast_unconfigured (ip)
21d21e91 TL	515	struct interface_info *ip;
b547818b TL	516	{
	517	return 1;
	518	}
	519
5cefe5e5 TL	520	int supports_multiple_interfaces (ip)
	521	struct interface_info *ip;
	522	{
	523	return 1;
	524	}
	525
d2bc90bd TL	526	void maybe_setup_fallback ()
d2bc90bd TL	527	{
acc21512	528	isc_result_t status;
20916cae TL	529	struct interface_info fbi = (struct interface_info )0;
20916cae TL	530	if (setup_fallback (&fbi, MDL)) {
d2bc90bd	531	if_register_fallback (fbi);
e92653f1	532	status = omapi_register_io_object ((omapi_object_t *)fbi,
acc21512 TL	533	if_readsocket, 0,
	534	fallback_discard, 0, 0);
	535	if (status != ISC_R_SUCCESS)
	536	log_fatal ("Can't register I/O handle for %s: %s",
	537	fbi -> name, isc_result_totext (status));
68e1f67a	538	interface_dereference (&fbi, MDL);
d2bc90bd TL	539	}
d2bc90bd TL	540	}
045820ee	541	#endif