/*

 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that: (1) source code distributions

 * retain the above copyright notice and this paragraph in its entirety, (2)

 * distributions including binary code include the above copyright notice and

 * this paragraph in its entirety in the documentation or other materials

 * provided with the distribution, and (3) all advertising materials mentioning

 * features or use of this software display the following acknowledgement:

 * ``This product includes software developed by the University of California,

 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of

 * the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 *

 * packet filter subroutines for tcpdump

 *	Extraction/creation by Jeffrey Mogul, DECWRL

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <sys/types.h>

#include <sys/time.h>

#include <sys/timeb.h>

#include <sys/socket.h>

#include <sys/file.h>

#include <sys/ioctl.h>

#include <net/pfilt.h>

struct mbuf;

struct rtentry;

#include <net/if.h>

#include <netinet/in.h>

#include <netinet/in_systm.h>

#include <netinet/ip.h>

#include <netinet/if_ether.h>

#include <netinet/ip_var.h>

#include <netinet/udp.h>

#include <netinet/udp_var.h>

#include <netinet/tcp.h>

#include <netinet/tcpip.h>

#include <ctype.h>

#include <errno.h>

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

/*

 * Make "pcap.h" not include "pcap/bpf.h"; we are going to include the

 * native OS version, as we need various BPF ioctls from it.

 */

#define PCAP_DONT_INCLUDE_PCAP_BPF_H

#include <net/bpf.h>

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H

#include "os-proto.h"

#endif

/*

 * FDDI packets are padded to make everything line up on a nice boundary.

 */

#define       PCAP_FDDIPAD 3

/*

 * Private data for capturing on Ultrix and DEC OSF/1^WDigital UNIX^W^W

 * Tru64 UNIX packetfilter devices.

 */

struct pcap_pf {

	int	filtering_in_kernel; /* using kernel filter */

	u_long	TotPkts;	/* can't oflow for 79 hrs on ether */

	u_long	TotAccepted;	/* count accepted by filter */

	u_long	TotDrops;	/* count of dropped packets */

	long	TotMissed;	/* missed by i/f during this run */

	long	OrigMissed;	/* missed by i/f before this run */

};

static int pcap_setfilter_pf(pcap_t *, struct bpf_program *);

/*

 * BUFSPACE is the size in bytes of the packet read buffer.  Most tcpdump

 * applications aren't going to need more than 200 bytes of packet header

 * and the read shouldn't return more packets than packetfilter's internal

 * queue limit (bounded at 256).

 */

#define BUFSPACE (200 * 256)

static int

pcap_read_pf(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)

{

	struct pcap_pf *pf = pc->priv;

	register u_char *p, *bp;

	register int cc, n, buflen, inc;

	register struct enstamp *sp;

#ifdef LBL_ALIGN

	struct enstamp stamp;

#endif

	register u_int pad;

 again:

	cc = pc->cc;

	if (cc == 0) {

		cc = read(pc->fd, (char *)pc->buffer + pc->offset, pc->bufsize);

		if (cc < 0) {

			if (errno == EWOULDBLOCK)

				return (0);

			if (errno == EINVAL &&

			    lseek(pc->fd, 0L, SEEK_CUR) + pc->bufsize < 0) {

				/*

				 * Due to a kernel bug, after 2^31 bytes,

				 * the kernel file offset overflows and

				 * read fails with EINVAL. The lseek()

				 * to 0 will fix things.

				 */

				(void)lseek(pc->fd, 0L, SEEK_SET);

				goto again;

			}

			pcap_fmt_errmsg_for_errno(pc->errbuf,

			    sizeof(pc->errbuf), errno, "pf read");

			return (-1);

		}

		bp = (u_char *)pc->buffer + pc->offset;

	} else

		bp = pc->bp;

	/*

	 * Loop through each packet.

	 */

	n = 0;

	pad = pc->fddipad;

	while (cc > 0) {

		/*

		 * Has "pcap_breakloop()" been called?

		 * If so, return immediately - if we haven't read any

		 * packets, clear the flag and return -2 to indicate

		 * that we were told to break out of the loop, otherwise

		 * leave the flag set, so that the *next* call will break

		 * out of the loop without having read any packets, and

		 * return the number of packets we've processed so far.

		 */

		if (pc->break_loop) {

			if (n == 0) {

				pc->break_loop = 0;

				return (-2);

			} else {

				pc->cc = cc;

				pc->bp = bp;

				return (n);

			}

		}

		if (cc < sizeof(*sp)) {

			pcap_snprintf(pc->errbuf, sizeof(pc->errbuf),

			    "pf short read (%d)", cc);

			return (-1);

		}

#ifdef LBL_ALIGN

		if ((long)bp & 3) {

			sp = &stam;;

			memcpy((char *)sp, (char *)bp, sizeof(*sp));

		} else

#endif

			sp = (struct enstamp *)bp;

		if (sp->ens_stamplen != sizeof(*sp)) {

			pcap_snprintf(pc->errbuf, sizeof(pc->errbuf),

			    "pf short stamplen (%d)",

			    sp->ens_stamplen);

			return (-1);

		}

		p = bp + sp->ens_stamplen;

		buflen = sp->ens_count;

		if (buflen > pc->snapshot)

			buflen = pc->snapshot;

		/* Calculate inc before possible pad update */

		inc = ENALIGN(buflen + sp->ens_stamplen);

		cc -= inc;

		bp += inc;

		pf->TotPkts++;

		pf->TotDrops += sp->ens_dropped;

		pf->TotMissed = sp->ens_ifoverflows;

		if (pf->OrigMissed < 0)

			pf->OrigMissed = pf->TotMissed;

		/*

		 * Short-circuit evaluation: if using BPF filter

		 * in kernel, no need to do it now - we already know

		 * the packet passed the filter.

		 *

		 * Note: the filter code was generated assuming

		 * that pc->fddipad was the amount of padding

		 * before the header, as that's what's required

		 * in the kernel, so we run the filter before

		 * skipping that padding.

		 */

		if (pf->filtering_in_kernel ||

		    bpf_filter(pc->fcode.bf_insns, p, sp->ens_count, buflen)) {

			struct pcap_pkthdr h;

			pf->TotAccepted++;

			h.ts = sp->ens_tstamp;

			h.len = sp->ens_count - pad;

			p += pad;

			buflen -= pad;

			h.caplen = buflen;

			(*callback)(user, &h, p);

			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {

				pc->cc = cc;

				pc->bp = bp;

				return (n);

			}

		}

	}

	pc->cc = 0;

	return (n);

}

static int

pcap_inject_pf(pcap_t *p, const void *buf, size_t size)

{

	int ret;

	ret = write(p->fd, buf, size);

	if (ret == -1) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "send");

		return (-1);

	}

	return (ret);

}

static int

pcap_stats_pf(pcap_t *p, struct pcap_stat *ps)

{

	struct pcap_pf *pf = p->priv;

	/*

	 * If packet filtering is being done in the kernel:

	 *

	 *	"ps_recv" counts only packets that passed the filter.

	 *	This does not include packets dropped because we

	 *	ran out of buffer space.  (XXX - perhaps it should,

	 *	by adding "ps_drop" to "ps_recv", for compatibility

	 *	with some other platforms.  On the other hand, on

	 *	some platforms "ps_recv" counts only packets that

	 *	passed the filter, and on others it counts packets

	 *	that didn't pass the filter....)

	 *

	 *	"ps_drop" counts packets that passed the kernel filter

	 *	(if any) but were dropped because the input queue was

	 *	full.

	 *

	 *	"ps_ifdrop" counts packets dropped by the network

	 *	inteface (regardless of whether they would have passed

	 *	the input filter, of course).

	 *

	 * If packet filtering is not being done in the kernel:

	 *

	 *	"ps_recv" counts only packets that passed the filter.

	 *

	 *	"ps_drop" counts packets that were dropped because the

	 *	input queue was full, regardless of whether they passed

	 *	the userland filter.

	 *

	 *	"ps_ifdrop" counts packets dropped by the network

	 *	inteface (regardless of whether they would have passed

	 *	the input filter, of course).

	 *

	 * These statistics don't include packets not yet read from

	 * the kernel by libpcap, but they may include packets not

	 * yet read from libpcap by the application.

	 */

	ps->ps_recv = pf->TotAccepted;

	ps->ps_drop = pf->TotDrops;

	ps->ps_ifdrop = pf->TotMissed - pf->OrigMissed;

	return (0);

}

/*

 * We include the OS's <net/bpf.h>, not our "pcap/bpf.h", so we probably

 * don't get DLT_DOCSIS defined.

 */

#ifndef DLT_DOCSIS

#define DLT_DOCSIS	143

#endif

static int

pcap_activate_pf(pcap_t *p)

{

	struct pcap_pf *pf = p->priv;

	short enmode;

	int backlog = -1;	/* request the most */

	struct enfilter Filter;

	struct endevp devparams;

	int err;

	/*

	 * Initially try a read/write open (to allow the inject

	 * method to work).  If that fails due to permission

	 * issues, fall back to read-only.  This allows a

	 * non-root user to be granted specific access to pcap

	 * capabilities via file permissions.

	 *

	 * XXX - we should have an API that has a flag that

	 * controls whether to open read-only or read-write,

	 * so that denial of permission to send (or inability

	 * to send, if sending packets isn't supported on

	 * the device in question) can be indicated at open

	 * time.

	 *

	 * XXX - we assume here that "pfopen()" does not, in fact, modify

	 * its argument, even though it takes a "char *" rather than a

	 * "const char *" as its first argument.  That appears to be

	 * the case, at least on Digital UNIX 4.0.

	 *

	 * XXX - is there an error that means "no such device"?  Is

	 * there one that means "that device doesn't support pf"?

	 */

	p->fd = pfopen(p->opt.device, O_RDWR);

	if (p->fd == -1 && errno == EACCES)

		p->fd = pfopen(p->opt.device, O_RDONLY);

	if (p->fd < 0) {

		if (errno == EACCES) {

			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

			    "pf open: %s: Permission denied\n"

"your system may not be properly configured; see the packetfilter(4) man page",

			    p->opt.device);

			err = PCAP_ERROR_PERM_DENIED;

		} else {

			pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

			    errno, "pf open: %s", p->opt.device);

			err = PCAP_ERROR;

		}

		goto bad;

	}

	/*

	 * Turn a negative snapshot value (invalid), a snapshot value of

	 * 0 (unspecified), or a value bigger than the normal maximum

	 * value, into the maximum allowed value.

	 *

	 * If some application really *needs* a bigger snapshot

	 * length, we should just increase MAXIMUM_SNAPLEN.

	 */

	if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)

		p->snapshot = MAXIMUM_SNAPLEN;

	pf->OrigMissed = -1;

	enmode = ENTSTAMP|ENNONEXCL;

	if (!p->opt.immediate)

		enmode |= ENBATCH;

	if (p->opt.promisc)

		enmode |= ENPROMISC;

	if (ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode) < 0) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "EIOCMBIS");

		err = PCAP_ERROR;

		goto bad;

	}

#ifdef	ENCOPYALL

	/* Try to set COPYALL mode so that we see packets to ourself */

	enmode = ENCOPYALL;

	(void)ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode);/* OK if this fails */

#endif

	/* set the backlog */

	if (ioctl(p->fd, EIOCSETW, (caddr_t)&backlog) < 0) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "EIOCSETW");

		err = PCAP_ERROR;

		goto bad;

	}

	/* discover interface type */

	if (ioctl(p->fd, EIOCDEVP, (caddr_t)&devparams) < 0) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "EIOCDEVP");

		err = PCAP_ERROR;

		goto bad;

	}

	/* HACK: to compile prior to Ultrix 4.2 */

#ifndef	ENDT_FDDI

#define	ENDT_FDDI	4

#endif

	switch (devparams.end_dev_type) {

	case ENDT_10MB:

		p->linktype = DLT_EN10MB;

		p->offset = 2;

		/*

		 * This is (presumably) a real Ethernet capture; give it a

		 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so

		 * that an application can let you choose it, in case you're

		 * capturing DOCSIS traffic that a Cisco Cable Modem

		 * Termination System is putting out onto an Ethernet (it

		 * doesn't put an Ethernet header onto the wire, it puts raw

		 * DOCSIS frames out on the wire inside the low-level

		 * Ethernet framing).

		 */

		p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);

		/*

		 * If that fails, just leave the list empty.

		 */

		if (p->dlt_list != NULL) {

			p->dlt_list[0] = DLT_EN10MB;

			p->dlt_list[1] = DLT_DOCSIS;

			p->dlt_count = 2;

		}

		break;

	case ENDT_FDDI:

		p->linktype = DLT_FDDI;

		break;

#ifdef ENDT_SLIP

	case ENDT_SLIP:

		p->linktype = DLT_SLIP;

		break;

#endif

#ifdef ENDT_PPP

	case ENDT_PPP:

		p->linktype = DLT_PPP;

		break;

#endif

#ifdef ENDT_LOOPBACK

	case ENDT_LOOPBACK:

		/*

		 * It appears to use Ethernet framing, at least on

		 * Digital UNIX 4.0.

		 */

		p->linktype = DLT_EN10MB;

		p->offset = 2;

		break;

#endif

#ifdef ENDT_TRN

	case ENDT_TRN:

		p->linktype = DLT_IEEE802;

		break;

#endif

	default:

		/*

		 * XXX - what about ENDT_IEEE802?  The pfilt.h header

		 * file calls this "IEEE 802 networks (non-Ethernet)",

		 * but that doesn't specify a specific link layer type;

		 * it could be 802.4, or 802.5 (except that 802.5 is

		 * ENDT_TRN), or 802.6, or 802.11, or....  That's why

		 * DLT_IEEE802 was hijacked to mean Token Ring in various

		 * BSDs, and why we went along with that hijacking.

		 *

		 * XXX - what about ENDT_HDLC and ENDT_NULL?

		 * Presumably, as ENDT_OTHER is just "Miscellaneous

		 * framing", there's not much we can do, as that

		 * doesn't specify a particular type of header.

		 */

		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

		    "unknown data-link type %u", devparams.end_dev_type);

		err = PCAP_ERROR;

		goto bad;

	}

	/* set truncation */

	if (p->linktype == DLT_FDDI) {

		p->fddipad = PCAP_FDDIPAD;

		/* packetfilter includes the padding in the snapshot */

		p->snapshot += PCAP_FDDIPAD;

	} else

		p->fddipad = 0;

	if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&p->snapshot) < 0) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "EIOCTRUNCATE");

		err = PCAP_ERROR;

		goto bad;

	}

	/* accept all packets */

	memset(&Filter, 0, sizeof(Filter));

	Filter.enf_Priority = 37;	/* anything > 2 */

	Filter.enf_FilterLen = 0;	/* means "always true" */

	if (ioctl(p->fd, EIOCSETF, (caddr_t)&Filter) < 0) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "EIOCSETF");

		err = PCAP_ERROR;

		goto bad;

	}

	if (p->opt.timeout != 0) {

		struct timeval timeout;

		timeout.tv_sec = p->opt.timeout / 1000;

		timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;

		if (ioctl(p->fd, EIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {

			pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

			    errno, "EIOCSRTIMEOUT");

			err = PCAP_ERROR;

			goto bad;

		}

	}

	p->bufsize = BUFSPACE;

	p->buffer = malloc(p->bufsize + p->offset);

	if (p->buffer == NULL) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "malloc");

		err = PCAP_ERROR;

		goto bad;

	}

	/*

	 * "select()" and "poll()" work on packetfilter devices.

	 */

	p->selectable_fd = p->fd;

	p->read_op = pcap_read_pf;

	p->inject_op = pcap_inject_pf;

	p->setfilter_op = pcap_setfilter_pf;

	p->setdirection_op = NULL;	/* Not implemented. */

	p->set_datalink_op = NULL;	/* can't change data link type */

	p->getnonblock_op = pcap_getnonblock_fd;

	p->setnonblock_op = pcap_setnonblock_fd;

	p->stats_op = pcap_stats_pf;

	return (0);

 bad:

	pcap_cleanup_live_common(p);

	return (err);

}

pcap_t *

pcap_create_interface(const char *device _U_, char *ebuf)

{

	pcap_t *p;

	p = pcap_create_common(ebuf, sizeof (struct pcap_pf));

	if (p == NULL)

		return (NULL);

	p->activate_op = pcap_activate_pf;

	return (p);

}

/*

 * XXX - is there an error from pfopen() that means "no such device"?

 * Is there one that means "that device doesn't support pf"?

 */

static int

can_be_bound(const char *name _U_)

{

	return (1);

}

static int

get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)

{

	/*

	 * Nothing we can do other than mark loopback devices as "the

	 * connected/disconnected status doesn't apply".

	 *

	 * XXX - is there a way to find out whether an adapter has

	 * something plugged into it?

	 */

	if (*flags & PCAP_IF_LOOPBACK) {

		/*

		 * Loopback devices aren't wireless, and "connected"/

		 * "disconnected" doesn't apply to them.

		 */

		*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;

		return (0);

	}

	return (0);

}

int

pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)

{

	return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,

	    get_if_flags));

}

static int

pcap_setfilter_pf(pcap_t *p, struct bpf_program *fp)

{

	struct pcap_pf *pf = p->priv;

	struct bpf_version bv;

	/*

	 * See if BIOCVERSION works.  If not, we assume the kernel doesn't

	 * support BPF-style filters (it's not documented in the bpf(7)

	 * or packetfiler(7) man pages, but the code used to fail if

	 * BIOCSETF worked but BIOCVERSION didn't, and I've seen it do

	 * kernel filtering in DU 4.0, so presumably BIOCVERSION works

	 * there, at least).

	 */

	if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) >= 0) {

		/*

		 * OK, we have the version of the BPF interpreter;

		 * is it the same major version as us, and the same

		 * or better minor version?

		 */

		if (bv.bv_major == BPF_MAJOR_VERSION &&

		    bv.bv_minor >= BPF_MINOR_VERSION) {

			/*

			 * Yes.  Try to install the filter.

			 */

			if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {

				pcap_fmt_errmsg_for_errno(p->errbuf,

				    sizeof(p->errbuf), errno, "BIOCSETF");

				return (-1);

			}

			/*

			 * OK, that succeeded.  We're doing filtering in

			 * the kernel.  (We assume we don't have a

			 * userland filter installed - that'd require

			 * a previous version check to have failed but

			 * this one to succeed.)

			 *

			 * XXX - this message should be supplied to the

			 * application as a warning of some sort,

			 * except that if it's a GUI application, it's

			 * not clear that it should be displayed in

			 * a window to annoy the user.

			 */

			fprintf(stderr, "tcpdump: Using kernel BPF filter\n");

			pf->filtering_in_kernel = 1;

			/*

			 * Discard any previously-received packets,

			 * as they might have passed whatever filter

			 * was formerly in effect, but might not pass

			 * this filter (BIOCSETF discards packets buffered

			 * in the kernel, so you can lose packets in any

			 * case).

			 */

			p->cc = 0;

			return (0);

		}

		/*

		 * We can't use the kernel's BPF interpreter; don't give

		 * up, just log a message and be inefficient.

		 *

		 * XXX - this should really be supplied to the application

		 * as a warning of some sort.

		 */

		fprintf(stderr,

	    "tcpdump: Requires BPF language %d.%d or higher; kernel is %d.%d\n",

		    BPF_MAJOR_VERSION, BPF_MINOR_VERSION,

		    bv.bv_major, bv.bv_minor);

	}

	/*

	 * We couldn't do filtering in the kernel; do it in userland.

	 */

	if (install_bpf_program(p, fp) < 0)

		return (-1);

	/*

	 * XXX - this message should be supplied by the application as

	 * a warning of some sort.

	 */

	fprintf(stderr, "tcpdump: Filtering in user process\n");

	pf->filtering_in_kernel = 0;

	return (0);

}

/*

 * Libpcap version string.

 */

const char *

pcap_lib_version(void)

{

	return (PCAP_VERSION_STRING);

}