freebsd/sys/netpfil/pf/if_pflog.c

/*-
 * The authors of this code are John Ioannidis (ji@tla.org),
 * Angelos D. Keromytis (kermit@csd.uch.gr) and
 * Niels Provos (provos@physnet.uni-hamburg.de).
 *
 * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
 * in November 1995.
 *
 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
 * by Angelos D. Keromytis.
 *
 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
 * and Niels Provos.
 *
 * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis
 * and Niels Provos.
 * Copyright (c) 2001, Angelos D. Keromytis, Niels Provos.
 *
 * Permission to use, copy, and modify this software with or without fee
 * is hereby granted, provided that this entire notice is included in
 * all copies of any software which is or includes a copy or
 * modification of this software.
 * You may use this code under the GNU public license if you so wish. Please
 * contribute changes back to the authors under this freer than GPL license
 * so that we may further the use of strong encryption without limitations to
 * all.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 *
 *	$OpenBSD: if_pflog.c,v 1.26 2007/10/18 21:58:18 mpf Exp $
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_bpf.h"
#include "opt_pf.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/sockio.h>

#include <net/bpf.h>
#include <net/if.h>
#include <net/if_clone.h>
#include <net/if_pflog.h>
#include <net/if_types.h>
#include <net/pfvar.h>

#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#endif
#ifdef	INET
#include <netinet/in_var.h>
#include <netinet/ip.h>
#endif

#ifdef INET6
#include <netinet6/in6_var.h>
#include <netinet6/nd6.h>
#endif /* INET6 */

#ifdef INET
#include <machine/in_cksum.h>
#endif /* INET */

#define PFLOGMTU	(32768 + MHLEN + MLEN)

#ifdef PFLOGDEBUG
#define DPRINTF(x)    do { if (pflogdebug) printf x ; } while (0)
#else
#define DPRINTF(x)
#endif

static int	pflogoutput(struct ifnet *, struct mbuf *,
		    const struct sockaddr *, struct route *);
static void	pflogattach(int);
static int	pflogioctl(struct ifnet *, u_long, caddr_t);
static void	pflogstart(struct ifnet *);
static int	pflog_clone_create(struct if_clone *, int, caddr_t);
static void	pflog_clone_destroy(struct ifnet *);
static struct if_clone *pflog_cloner;

static const char pflogname[] = "pflog";

struct ifnet	*pflogifs[PFLOGIFS_MAX];	/* for fast access */

static void
pflogattach(int npflog)
{
	int	i;
	for (i = 0; i < PFLOGIFS_MAX; i++)
		pflogifs[i] = NULL;
	pflog_cloner = if_clone_simple(pflogname, pflog_clone_create,
	    pflog_clone_destroy, 1);
}

static int
pflog_clone_create(struct if_clone *ifc, int unit, caddr_t param)
{
	struct ifnet *ifp;

	if (unit >= PFLOGIFS_MAX)
		return (EINVAL);

	ifp = if_alloc(IFT_PFLOG);
	if (ifp == NULL) {
		return (ENOSPC);
	}
	if_initname(ifp, pflogname, unit);
	ifp->if_mtu = PFLOGMTU;
	ifp->if_ioctl = pflogioctl;
	ifp->if_output = pflogoutput;
	ifp->if_start = pflogstart;
	ifp->if_snd.ifq_maxlen = ifqmaxlen;
	ifp->if_hdrlen = PFLOG_HDRLEN;
	if_attach(ifp);

	bpfattach(ifp, DLT_PFLOG, PFLOG_HDRLEN);

	pflogifs[unit] = ifp;

	return (0);
}

static void
pflog_clone_destroy(struct ifnet *ifp)
{
	int i;

	for (i = 0; i < PFLOGIFS_MAX; i++)
		if (pflogifs[i] == ifp)
			pflogifs[i] = NULL;

	bpfdetach(ifp);
	if_detach(ifp);
	if_free(ifp);
}

/*
 * Start output on the pflog interface.
 */
static void
pflogstart(struct ifnet *ifp)
{
	struct mbuf *m;

	for (;;) {
		IF_LOCK(&ifp->if_snd);
		_IF_DROP(&ifp->if_snd);
		_IF_DEQUEUE(&ifp->if_snd, m);
		IF_UNLOCK(&ifp->if_snd);

		if (m == NULL)
			return;
		else
			m_freem(m);
	}
}

static int
pflogoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
	struct route *rt)
{
	m_freem(m);
	return (0);
}

/* ARGSUSED */
static int
pflogioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
	switch (cmd) {
	case SIOCSIFFLAGS:
		if (ifp->if_flags & IFF_UP)
			ifp->if_drv_flags |= IFF_DRV_RUNNING;
		else
			ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
		break;
	default:
		return (ENOTTY);
	}

	return (0);
}

static int
pflog_packet(struct pfi_kif *kif, struct mbuf *m, sa_family_t af, u_int8_t dir,
    u_int8_t reason, struct pf_rule *rm, struct pf_rule *am,
    struct pf_ruleset *ruleset, struct pf_pdesc *pd, int lookupsafe)
{
	struct ifnet *ifn;
	struct pfloghdr hdr;

	if (kif == NULL || m == NULL || rm == NULL || pd == NULL)
		return ( 1);

	if ((ifn = pflogifs[rm->logif]) == NULL || !ifn->if_bpf)
		return (0);

	bzero(&hdr, sizeof(hdr));
	hdr.length = PFLOG_REAL_HDRLEN;
	hdr.af = af;
	hdr.action = rm->action;
	hdr.reason = reason;
	memcpy(hdr.ifname, kif->pfik_name, sizeof(hdr.ifname));

	if (am == NULL) {
		hdr.rulenr = htonl(rm->nr);
		hdr.subrulenr =  1;
	} else {
		hdr.rulenr = htonl(am->nr);
		hdr.subrulenr = htonl(rm->nr);
		if (ruleset != NULL && ruleset->anchor != NULL)
			strlcpy(hdr.ruleset, ruleset->anchor->name,
			    sizeof(hdr.ruleset));
	}
	/*
	 * XXXGL: we avoid pf_socket_lookup() when we are holding
	 * state lock, since this leads to unsafe LOR.
	 * These conditions are very very rare, however.
	 */
	if (rm->log & PF_LOG_SOCKET_LOOKUP && !pd->lookup.done && lookupsafe)
		pd->lookup.done = pf_socket_lookup(dir, pd, m);
	if (pd->lookup.done > 0)
		hdr.uid = pd->lookup.uid;
	else
		hdr.uid = UID_MAX;
	hdr.pid = NO_PID;
	hdr.rule_uid = rm->cuid;
	hdr.rule_pid = rm->cpid;
	hdr.dir = dir;

#ifdef INET
	if (af == AF_INET && dir == PF_OUT) {
		struct ip *ip;

		ip = mtod(m, struct ip *);
		ip->ip_sum = 0;
		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
	}
#endif /* INET */

	ifn->if_opackets++;
	ifn->if_obytes += m->m_pkthdr.len;
	BPF_MTAP2(ifn, &hdr, PFLOG_HDRLEN, m);

	return (0);
}

static int
pflog_modevent(module_t mod, int type, void *data)
{
	int error = 0;

	switch (type) {
	case MOD_LOAD:
		pflogattach(1);
		PF_RULES_WLOCK();
		pflog_packet_ptr = pflog_packet;
		PF_RULES_WUNLOCK();
		break;
	case MOD_UNLOAD:
		PF_RULES_WLOCK();
		pflog_packet_ptr = NULL;
		PF_RULES_WUNLOCK();
		if_clone_detach(pflog_cloner);
		break;
	default:
		error = EINVAL;
		break;
	}

	return error;
}

static moduledata_t pflog_mod = { pflogname, pflog_modevent, 0 };

#define PFLOG_MODVER 1

DECLARE_MODULE(pflog, pflog_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(pflog, PFLOG_MODVER);
MODULE_DEPEND(pflog, pf, PF_MODVER, PF_MODVER, PF_MODVER);