mli_ipl.c - net/ipfilter - Rivoreo Source Code Repositories

 /*
  * Copyright (C) 1993-2001 by Darren Reed.
  * (C)opyright 1997 by Marc Boucher.
  *
  * See the IPFILTER.LICENCE file for details on licencing.
  */

 /* TODO: (MARCXXX)
 	- ipl_init failure -> open ENODEV or whatever
 	- prevent multiple LKM loads
 	- surround access to ifnet structures by IFNET_LOCK()/IFNET_UNLOCK() ?
 	- m != m1 problem
 */

 #include <sys/types.h>
 #include <sys/conf.h>
 #ifdef IPFILTER_LKM
 #include <sys/mload.h>
 #endif
 #include <sys/systm.h>
 #include <sys/errno.h>
 #include <net/if.h>
 #include <net/route.h>
 #include <netinet/in.h>
 #ifdef IFF_DRVRLOCK /* IRIX6 */
 #include <sys/hashing.h>
 #include <netinet/in_var.h>
 #endif
 #include <sys/mbuf.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/ip_var.h>
 #include <netinet/tcp.h>
 #include <netinet/udp.h>
 #include <netinet/tcpip.h>
 #include <netinet/ip_icmp.h>
 #include <netinet/ipfilter.h>
 #include "ipl.h"
 #include "ip_compat.h"
 #include "ip_fil.h"
 #include "ip_nat.h"

 /*#define IPFDEBUG 1*/

 unsigned IPL_EXTERN(devflag) = D_MP;
 #ifdef IPFILTER_LKM
 char *IPL_EXTERN(mversion) = M_VERSION;
 #endif

 kmutex_t ipl_mutex, ipf_mutex, ipfi_mutex, ipf_rw;
 kmutex_t ipf_frag, ipf_state, ipf_nat, ipf_natfrag, ipf_auth;

 int     (*fr_checkp) __P((struct ip *, int, void *, int, mb_t **));

 #ifdef IPFILTER_LKM
 static int *ipff_addr = 0;
 static int ipff_value;
 static __psunsigned_t *ipfk_addr = 0;
 static __psunsigned_t ipfk_code[4];
 #endif

 typedef	struct	nif	{
 	struct	nif	*nf_next;
 	struct ifnet	*nf_ifp;
 #if IRIX < 605
 	int     (*nf_output)(struct ifnet *, struct mbuf *, struct sockaddr *);
 #else
 	int     (*nf_output)(struct ifnet *, struct mbuf *, struct sockaddr *,
 			     struct rtentry *);
 #endif
 	char	nf_name[IFNAMSIZ];
 	int	nf_unit;
 } nif_t;

 static nif_t *nif_head = 0;
 static int nif_interfaces = 0;
 extern int in_interfaces;

 extern ipnat_t *nat_list;

 static int
 #if IRIX < 605
 ipl_if_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst)
 #else
 ipl_if_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 	      struct rtentry *rt)
 #endif
 {
 	nif_t *nif;

 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
 	for (nif = nif_head; nif; nif = nif->nf_next)
 		if (nif->nf_ifp == ifp)
 			break;

 	MUTEX_EXIT(&ipfi_mutex);
 	if (!nif) {
 		printf("IP Filter: ipl_if_output intf %x NOT FOUND\n", ifp);
 		return ENETDOWN;
 	}

 #if	IPFDEBUG >= 4
 	static unsigned int cnt = 0;
 	if ((++cnt % 200) == 0)
 		printf("IP Filter: ipl_if_output(ifp=0x%lx, m=0x%lx, dst=0x%lx), m_type=%d m_flags=0x%lx m_off=0x%lx\n", ifp, m, dst, m->m_type, (unsigned long)(m->m_flags), m->m_off);
 #endif
 	if (fr_checkp) {
 		struct mbuf *m1 = m;
 		struct ip *ip;
 		int hlen;

 		switch(m->m_type) {
 		case MT_DATA:
 			if (m->m_flags & M_BCAST) {
 #if	IPFDEBUG >= 2
 				printf("IP Filter: ipl_if_output: passing M_BCAST\n");
 #endif
 				break;
 			}
 			/* FALLTHROUGH */
 		case MT_HEADER:
 #if	IPFDEBUG >= 4
 			if (!MBUF_IS_CLUSTER(m) && ((m->m_off < MMINOFF) || (m->m_off > MMAXOFF))) {
 				printf("IP Filter: ipl_if_output: bad m_off m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
 				goto done;
 			}
 #endif
 			if (m->m_len < sizeof(char)) {
 				printf("IP Filter: ipl_if_output: mbuf block too small (m_len=%d) for IP vers+hlen, m_type=%d m_flags=0x%lx\n", m->m_len, m->m_type, (unsigned long)(m->m_flags));
 				goto done;
 			}
 			ip = mtod(m, struct ip *);
 			if (ip->ip_v != IPVERSION) {
 #if	IPFDEBUG >= 4
 				printf("IP Filter: ipl_if_output: bad ip_v m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
 #endif
 				goto done;
 			}

 			hlen = ip->ip_hl << 2;
 			if ((*fr_checkp)(ip, hlen, ifp, 1, &m1))
 				return EHOSTUNREACH;

 			if (!m1)
 				return 0;

 			m = m1;
 			break;

 		default:
 			printf("IP Filter: ipl_if_output: bad m_type=%d m_flags=0x%lxm_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
 			break;
 		}
 	}
 done:
 #if IRIX < 605
 	return (*nif->nf_output)(ifp, m, dst);
 #else
 	return (*nif->nf_output)(ifp, m, dst, rt);
 #endif
 }

 int
 IPL_EXTERN(_kernel)(struct ifnet *rcvif, struct mbuf *m)
 {
 #if	IPFDEBUG >= 4
 	static unsigned int cnt = 0;
 	if ((++cnt % 200) == 0)
 		printf("IP Filter: ipl_ipfilter_kernel(rcvif=0x%lx, m=0x%lx\n", rcvif, m);
 #endif

 	/*
 	 * Check if we want to allow this packet to be processed.
 	 * Consider it to be bad if not.
 	 */
 	if (fr_checkp) {
 		struct mbuf *m1 = m;
 		struct ip *ip;
 		int hlen;

 		if ((m->m_type != MT_DATA) && (m->m_type != MT_HEADER)) {
 			printf("IP Filter: ipl_ipfilter_kernel: bad m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
 			return IPF_ACCEPTIT;
 		}

 #if	IPFDEBUG >= 4
 		if (!MBUF_IS_CLUSTER(m) && ((m->m_off < MMINOFF) || (m->m_off > MMAXOFF))) {
 			printf("IP Filter: ipl_ipfilter_kernel: bad m_off m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
 			return IPF_ACCEPTIT;
 		}
 #endif
 		if (m->m_len < sizeof(char)) {
 			printf("IP Filter: ipl_ipfilter_kernel: mbuf block too small (m_len=%d) for IP vers+hlen, m_type=%d m_flags=0x%lx\n", m->m_len, m->m_type, (unsigned long)(m->m_flags));
 			return IPF_ACCEPTIT;
 		}
 		ip = mtod(m, struct ip *);
 		if (ip->ip_v != IPVERSION) {
 			printf("IP Filter: ipl_ipfilter_kernel: bad ip_v\n");
 			m_freem(m);
 			return IPF_DROPIT;
 		}

 		hlen = ip->ip_hl << 2;
 		if ((*fr_checkp)(ip, hlen, rcvif, 0, &m1) || !m1)
 			return IPF_DROPIT;
 		if (m != m1)
 			printf("IP Filter: ipl_ipfilter_kernel: m != m1\n");
 	}

 	return IPF_ACCEPTIT;
 }

 static int
 ipfilterattach(void)
 {
 #ifdef IPFILTER_LKM
 	__psunsigned_t *addr_ff, *addr_fk;

 	st_findaddr("ipfilterflag", &addr_ff);
 #if	IPFDEBUG >= 4
 	printf("IP Filter: st_findaddr ipfilterflag=0x%lx\n", addr_ff);
 #endif
 	if (!addr_ff)
 		return ESRCH;

 	st_findaddr("ipfilter_kernel", &addr_fk);
 #if	IPFDEBUG >= 4
 	printf("IP Filter: st_findaddr ipfilter_kernel=0x%lx\n", addr_fk);
 #endif
 	if (!addr_fk)
 		return ESRCH;

 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

 	ipff_addr = (int *)addr_ff;

 	ipff_value = *ipff_addr;
 	*ipff_addr = 0;


 	ipfk_addr = addr_fk;

 	bcopy(ipfk_addr, ipfk_code,
 		sizeof(ipfk_code));

 	/* write a "li t4, ipl_ipfilter_kernel" instruction */
 	ipfk_addr[0] = 0x3c0c0000 |
 		       (((__psunsigned_t)IPL_EXTERN(_kernel) >> 16) & 0xffff);
 	ipfk_addr[1] = 0x358c0000 |
 		       ((__psunsigned_t)IPL_EXTERN(_kernel) & 0xffff);
 	/* write a "jr t4" instruction" */
 	ipfk_addr[2] = 0x01800008;

 	/* write a "nop" instruction */
 	ipfk_addr[3] = 0;

 	icache_inval(ipfk_addr, sizeof(ipfk_code));

 	*ipff_addr = 1; /* enable ipfilter_kernel */

 	MUTEX_EXIT(&ipfi_mutex);
 #else
 	extern int ipfilterflag;

 	ipfilterflag = 1;
 #endif

 	return 0;
 }

 /*
  * attach the packet filter to each non-loopback interface that is running
  */
 static void
 nifattach()
 {
 	struct ifnet *ifp;
 	struct frentry *f;
 	ipnat_t *np;
 	nif_t *nif;

 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

 	for (ifp = ifnet; ifp; ifp = ifp->if_next) {
 		if ((!(ifp->if_flags & IFF_RUNNING)) ||
 			(ifp->if_flags & IFF_LOOPBACK))
 			continue;

 		/*
 		 * Look for entry already setup for this device
 		 */
 		for (nif = nif_head; nif; nif = nif->nf_next)
 			if (nif->nf_ifp == ifp)
 				break;
 		if (nif)
 			continue;

 		if (ifp->if_output == ipl_if_output) {
 			printf("IP Filter: ERROR INTF 0x%lx STILL ATTACHED\n",
 				ifp);
 			continue;
 		}
 #if	IPFDEBUG >= 4
 		printf("IP Filter: nifattach nif %x opt %x\n",
 		       ifp, ifp->if_output);
 #endif
 		KMALLOC(nif, nif_t *);
 		if (!nif) {
 			printf("IP Filter: malloc(%d) for nif_t failed\n",
 			       sizeof(nif_t));
 			continue;
 		}

 		nif->nf_ifp = ifp;
 		strncpy(nif->nf_name, ifp->if_name, sizeof(nif->nf_name));
 		nif->nf_name[sizeof(nif->nf_name) - 1] = '\0';
 		nif->nf_unit = ifp->if_unit;

 		nif->nf_next = nif_head;
 		nif_head = nif;

 		/*
 		 * Activate any rules directly associated with this interface
 		 */
 		MUTEX_ENTER(&ipf_mutex);
 		for (f = ipfilter[0][0]; f; f = f->fr_next) {
 			if ((f->fr_ifa == (struct ifnet *)-1)) {
 				if (f->fr_ifname[0] &&
 				    (GETUNIT(f->fr_ifname, 4) == ifp))
 					f->fr_ifa = ifp;
 			}
 		}
 		for (f = ipfilter[1][0]; f; f = f->fr_next) {
 			if ((f->fr_ifa == (struct ifnet *)-1)) {
 				if (f->fr_ifname[0] &&
 				    (GETUNIT(f->fr_ifname, 4) == ifp))
 					f->fr_ifa = ifp;
 			}
 		}
 		MUTEX_EXIT(&ipf_mutex);
 		MUTEX_ENTER(&ipf_nat);
 		for (np = nat_list; np; np = np->in_next) {
 			if ((np->in_ifp == (void *)-1)) {
 				if (np->in_ifname[0] &&
 				    (GETUNIT(np->in_ifname, 4) == ifp))
 					np->in_ifp = (void *)ifp;
 			}
 		}
 		MUTEX_EXIT(&ipf_nat);

 		nif->nf_output = ifp->if_output;
 		ifp->if_output = ipl_if_output;

 #if	IPFDEBUG >= 4
 		printf("IP Filter: nifattach: ifp(%lx)->if_output FROM %lx TO %lx\n",
 			ifp, nif->nf_output, ifp->if_output);
 #endif

 		printf("IP Filter: attach to [%s,%d]\n",
 			nif->nf_name, ifp->if_unit);
 	}
 	if (!nif_head)
 		printf("IP Filter: not attached to any interfaces\n");

 	nif_interfaces = in_interfaces;

 	MUTEX_EXIT(&ipfi_mutex);

 	return;
 }

 /*
  * look for bad consistancies between the list of interfaces the filter knows
  * about and those which are currently configured.
  */
 int
 ipfsync(void)
 {
 	register struct frentry *f;
 	register ipnat_t *np;
 	register nif_t *nif, **qp;
 	register struct ifnet *ifp;

 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
 	for (qp = &nif_head; (nif = *qp); ) {
 		for (ifp = ifnet; ifp; ifp = ifp->if_next)
 			if ((nif->nf_ifp == ifp) &&
 			    (nif->nf_unit == ifp->if_unit) &&
 			    !strcmp(nif->nf_name, ifp->if_name)) {
 				break;
 			}
 		if (ifp) {
 			qp = &nif->nf_next;
 			continue;
 		}
 		printf("IP Filter: detaching [%s]\n", nif->nf_name);
 		*qp = nif->nf_next;

 		/*
 		 * Disable any rules directly associated with this interface
 		 */
 		MUTEX_ENTER(&ipf_mutex);
 		for (f = ipfilter[0][0]; f; f = f->fr_next)
 			if (f->fr_ifa == (void *)nif->nf_ifp)
 				f->fr_ifa = (struct ifnet *)-1;
 		for (f = ipfilter[1][0]; f; f = f->fr_next)
 			if (f->fr_ifa == (void *)nif->nf_ifp)
 				f->fr_ifa = (struct ifnet *)-1;
 		MUTEX_EXIT(&ipf_mutex);
 		MUTEX_ENTER(&ipf_nat);
 		for (np = nat_list; np; np = np->in_next)
 			if (np->in_ifp == (void *)nif->nf_ifp)
 				np->in_ifp =(struct ifnet *)-1;
 		MUTEX_EXIT(&ipf_nat);

 		KFREE(nif);
 		nif = *qp;
 	}
 	MUTEX_EXIT(&ipfi_mutex);

 	nifattach();

 	return 0;
 }


 /*
  * unhook the IP filter from all defined interfaces with IP addresses
  */
 static void
 nifdetach()
 {
 	struct ifnet *ifp;
 	nif_t *nif, **qp;

 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
 	/*
 	 * Make two passes, first get rid of all the unknown devices, next
 	 * unlink known devices.
 	 */
 	for (qp = &nif_head; (nif = *qp); ) {
 		for (ifp = ifnet; ifp; ifp = ifp->if_next)
 			if (nif->nf_ifp == ifp)
 				break;
 		if (ifp) {
 			qp = &nif->nf_next;
 			continue;
 		}
 		printf("IP Filter: removing [%s]\n", nif->nf_name);
 		*qp = nif->nf_next;
 		KFREE(nif);
 	}

 	while ((nif = nif_head)) {
 		nif_head = nif->nf_next;
 		for (ifp = ifnet; ifp; ifp = ifp->if_next)
 			if (nif->nf_ifp == ifp)
 				break;
 		if (ifp) {
 			printf("IP Filter: detaching [%s,%d]\n",
 				nif->nf_name, ifp->if_unit);

 #if	IPFDEBUG >= 4
 			printf("IP Filter: nifdetach: ifp(%lx)->if_output FROM %lx TO %lx\n",
 				ifp, ifp->if_output, nif->nf_output);
 #endif
 			ifp->if_output = nif->nf_output;
 		}
 		KFREE(nif);
 	}
 	MUTEX_EXIT(&ipfi_mutex);

 	return;
 }


 static void
 ipfilterdetach(void)
 {
 #ifdef IPFILTER_LKM
 	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

 	if (ipff_addr) {
 		*ipff_addr = 0;

 		if (ipfk_addr)
 			bcopy(ipfk_code, ipfk_addr, sizeof(ipfk_code));

 		*ipff_addr = ipff_value;
 	}

 	MUTEX_EXIT(&ipfi_mutex);
 #else
 	extern int ipfilterflag;

 	ipfilterflag = 0;
 #endif
 }

 /* called by ipldetach() */
 void
 ipfilter_sgi_detach(void)
 {
 	nifdetach();

 	ipfilterdetach();
 }

 /* called by iplattach() */
 int
 ipfilter_sgi_attach(void)
 {
 	int error;

 	nif_interfaces = 0;

 	error = ipfilterattach();

 	if (!error)
 		nifattach();

 	return error;
 }

 /* this function is called from ipfr_slowtimer at 500ms intervals to
    keep our interface list in sync */
 void
 ipfilter_sgi_intfsync(void)
 {
 	MUTEX_ENTER(&ipfi_mutex);
 	if (nif_interfaces != in_interfaces) {
 		/* if the number of interfaces has changed, resync */
 		MUTEX_EXIT(&ipfi_mutex);
 		ipfsync();
 	} else
 		MUTEX_EXIT(&ipfi_mutex);
 }

 #ifdef IPFILTER_LKM
 /* this routine should be treated as an interrupt routine and should
    not call any routines that would cause it to sleep, such as: biowait(),
    sleep(), psema() or delay().
 */
 int
 IPL_EXTERN(unload)(void)
 {
 	int error = 0;

 	error = ipldetach();

 	LOCK_DEALLOC(ipl_mutex.l);
 	LOCK_DEALLOC(ipf_rw.l);
 	LOCK_DEALLOC(ipf_auth.l);
 	LOCK_DEALLOC(ipf_natfrag.l);
 	LOCK_DEALLOC(ipf_nat.l);
 	LOCK_DEALLOC(ipf_state.l);
 	LOCK_DEALLOC(ipf_frag.l);
 	LOCK_DEALLOC(ipf_mutex.l);
 	LOCK_DEALLOC(ipfi_mutex.l);

 	return error;
 }
 #endif

 void
 IPL_EXTERN(init)(void)
 {
 #ifdef IPFILTER_LKM
 	int error;
 #endif

 	ipfi_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_frag.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_state.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_nat.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_natfrag.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_auth.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipf_rw.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
 	ipl_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);

 	if (!ipfi_mutex.l || !ipf_mutex.l || !ipf_frag.l || !ipf_state.l ||
 	    !ipf_nat.l || !ipf_natfrag.l || !ipf_auth.l || !ipf_rw.l ||
 	    !ipl_mutex.l)
 		panic("IP Filter: LOCK_ALLOC failed");

 #ifdef IPFILTER_LKM
 	error = iplattach();
 	if (error) {
 		IPL_EXTERN(unload)();
 	}
 #endif

 	return;
 }
	/*
	* Copyright (C) 1993-2001 by Darren Reed.
	* (C)opyright 1997 by Marc Boucher.
	*
	* See the IPFILTER.LICENCE file for details on licencing.
	*/

	/* TODO: (MARCXXX)
	- ipl_init failure -> open ENODEV or whatever
	- prevent multiple LKM loads
	- surround access to ifnet structures by IFNET_LOCK()/IFNET_UNLOCK() ?
	- m != m1 problem
	*/

	#include <sys/types.h>
	#include <sys/conf.h>
	#ifdef IPFILTER_LKM
	#include <sys/mload.h>
	#endif
	#include <sys/systm.h>
	#include <sys/errno.h>
	#include <net/if.h>
	#include <net/route.h>
	#include <netinet/in.h>
	#ifdef IFF_DRVRLOCK /* IRIX6 */
	#include <sys/hashing.h>
	#include <netinet/in_var.h>
	#endif
	#include <sys/mbuf.h>
	#include <netinet/in_systm.h>
	#include <netinet/ip.h>
	#include <netinet/ip_var.h>
	#include <netinet/tcp.h>
	#include <netinet/udp.h>
	#include <netinet/tcpip.h>
	#include <netinet/ip_icmp.h>
	#include <netinet/ipfilter.h>
	#include "ipl.h"
	#include "ip_compat.h"
	#include "ip_fil.h"
	#include "ip_nat.h"

	/#define IPFDEBUG 1/

	unsigned IPL_EXTERN(devflag) = D_MP;
	#ifdef IPFILTER_LKM
	char *IPL_EXTERN(mversion) = M_VERSION;
	#endif

	kmutex_t ipl_mutex, ipf_mutex, ipfi_mutex, ipf_rw;
	kmutex_t ipf_frag, ipf_state, ipf_nat, ipf_natfrag, ipf_auth;

	int (fr_checkp) __P((struct ip , int, void , int, mb_t *));

	#ifdef IPFILTER_LKM
	static int *ipff_addr = 0;
	static int ipff_value;
	static __psunsigned_t *ipfk_addr = 0;
	static __psunsigned_t ipfk_code[4];
	#endif

	typedef struct nif {
	struct nif *nf_next;
	struct ifnet *nf_ifp;
	#if IRIX < 605
	int (nf_output)(struct ifnet , struct mbuf , struct sockaddr );
	#else
	int (nf_output)(struct ifnet , struct mbuf , struct sockaddr ,
	struct rtentry *);
	#endif
	char nf_name[IFNAMSIZ];
	int nf_unit;
	} nif_t;

	static nif_t *nif_head = 0;
	static int nif_interfaces = 0;
	extern int in_interfaces;

	extern ipnat_t *nat_list;

	static int
	#if IRIX < 605
	ipl_if_output(struct ifnet ifp, struct mbuf m, struct sockaddr *dst)
	#else
	ipl_if_output(struct ifnet ifp, struct mbuf m, struct sockaddr *dst,
	struct rtentry *rt)
	#endif
	{
	nif_t *nif;

	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
	for (nif = nif_head; nif; nif = nif->nf_next)
	if (nif->nf_ifp == ifp)
	break;

	MUTEX_EXIT(&ipfi_mutex);
	if (!nif) {
	printf("IP Filter: ipl_if_output intf %x NOT FOUND\n", ifp);
	return ENETDOWN;
	}

	#if IPFDEBUG >= 4
	static unsigned int cnt = 0;
	if ((++cnt % 200) == 0)
	printf("IP Filter: ipl_if_output(ifp=0x%lx, m=0x%lx, dst=0x%lx), m_type=%d m_flags=0x%lx m_off=0x%lx\n", ifp, m, dst, m->m_type, (unsigned long)(m->m_flags), m->m_off);
	#endif
	if (fr_checkp) {
	struct mbuf *m1 = m;
	struct ip *ip;
	int hlen;

	switch(m->m_type) {
	case MT_DATA:
	if (m->m_flags & M_BCAST) {
	#if IPFDEBUG >= 2
	printf("IP Filter: ipl_if_output: passing M_BCAST\n");
	#endif
	break;
	}
	/* FALLTHROUGH */
	case MT_HEADER:
	#if IPFDEBUG >= 4
	if (!MBUF_IS_CLUSTER(m) && ((m->m_off < MMINOFF) \|\| (m->m_off > MMAXOFF))) {
	printf("IP Filter: ipl_if_output: bad m_off m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
	goto done;
	}
	#endif
	if (m->m_len < sizeof(char)) {
	printf("IP Filter: ipl_if_output: mbuf block too small (m_len=%d) for IP vers+hlen, m_type=%d m_flags=0x%lx\n", m->m_len, m->m_type, (unsigned long)(m->m_flags));
	goto done;
	}
	ip = mtod(m, struct ip *);
	if (ip->ip_v != IPVERSION) {
	#if IPFDEBUG >= 4
	printf("IP Filter: ipl_if_output: bad ip_v m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
	#endif
	goto done;
	}

	hlen = ip->ip_hl << 2;
	if ((*fr_checkp)(ip, hlen, ifp, 1, &m1))
	return EHOSTUNREACH;

	if (!m1)
	return 0;

	m = m1;
	break;

	default:
	printf("IP Filter: ipl_if_output: bad m_type=%d m_flags=0x%lxm_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
	break;
	}
	}
	done:
	#if IRIX < 605
	return (*nif->nf_output)(ifp, m, dst);
	#else
	return (*nif->nf_output)(ifp, m, dst, rt);
	#endif
	}

	int
	IPL_EXTERN(_kernel)(struct ifnet rcvif, struct mbuf m)
	{
	#if IPFDEBUG >= 4
	static unsigned int cnt = 0;
	if ((++cnt % 200) == 0)
	printf("IP Filter: ipl_ipfilter_kernel(rcvif=0x%lx, m=0x%lx\n", rcvif, m);
	#endif

	/*
	* Check if we want to allow this packet to be processed.
	* Consider it to be bad if not.
	*/
	if (fr_checkp) {
	struct mbuf *m1 = m;
	struct ip *ip;
	int hlen;

	if ((m->m_type != MT_DATA) && (m->m_type != MT_HEADER)) {
	printf("IP Filter: ipl_ipfilter_kernel: bad m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
	return IPF_ACCEPTIT;
	}

	#if IPFDEBUG >= 4
	if (!MBUF_IS_CLUSTER(m) && ((m->m_off < MMINOFF) \|\| (m->m_off > MMAXOFF))) {
	printf("IP Filter: ipl_ipfilter_kernel: bad m_off m_type=%d m_flags=0x%lx m_off=0x%lx\n", m->m_type, (unsigned long)(m->m_flags), m->m_off);
	return IPF_ACCEPTIT;
	}
	#endif
	if (m->m_len < sizeof(char)) {
	printf("IP Filter: ipl_ipfilter_kernel: mbuf block too small (m_len=%d) for IP vers+hlen, m_type=%d m_flags=0x%lx\n", m->m_len, m->m_type, (unsigned long)(m->m_flags));
	return IPF_ACCEPTIT;
	}
	ip = mtod(m, struct ip *);
	if (ip->ip_v != IPVERSION) {
	printf("IP Filter: ipl_ipfilter_kernel: bad ip_v\n");
	m_freem(m);
	return IPF_DROPIT;
	}

	hlen = ip->ip_hl << 2;
	if ((*fr_checkp)(ip, hlen, rcvif, 0, &m1) \|\| !m1)
	return IPF_DROPIT;
	if (m != m1)
	printf("IP Filter: ipl_ipfilter_kernel: m != m1\n");
	}

	return IPF_ACCEPTIT;
	}

	static int
	ipfilterattach(void)
	{
	#ifdef IPFILTER_LKM
	__psunsigned_t addr_ff, addr_fk;

	st_findaddr("ipfilterflag", &addr_ff);
	#if IPFDEBUG >= 4
	printf("IP Filter: st_findaddr ipfilterflag=0x%lx\n", addr_ff);
	#endif
	if (!addr_ff)
	return ESRCH;

	st_findaddr("ipfilter_kernel", &addr_fk);
	#if IPFDEBUG >= 4
	printf("IP Filter: st_findaddr ipfilter_kernel=0x%lx\n", addr_fk);
	#endif
	if (!addr_fk)
	return ESRCH;

	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

	ipff_addr = (int *)addr_ff;

	ipff_value = *ipff_addr;
	*ipff_addr = 0;


	ipfk_addr = addr_fk;

	bcopy(ipfk_addr, ipfk_code,
	sizeof(ipfk_code));

	/* write a "li t4, ipl_ipfilter_kernel" instruction */
	ipfk_addr[0] = 0x3c0c0000 \|
	(((__psunsigned_t)IPL_EXTERN(_kernel) >> 16) & 0xffff);
	ipfk_addr[1] = 0x358c0000 \|
	((__psunsigned_t)IPL_EXTERN(_kernel) & 0xffff);
	/* write a "jr t4" instruction" */
	ipfk_addr[2] = 0x01800008;

	/* write a "nop" instruction */
	ipfk_addr[3] = 0;

	icache_inval(ipfk_addr, sizeof(ipfk_code));

	ipff_addr = 1; / enable ipfilter_kernel */

	MUTEX_EXIT(&ipfi_mutex);
	#else
	extern int ipfilterflag;

	ipfilterflag = 1;
	#endif

	return 0;
	}

	/*
	* attach the packet filter to each non-loopback interface that is running
	*/
	static void
	nifattach()
	{
	struct ifnet *ifp;
	struct frentry *f;
	ipnat_t *np;
	nif_t *nif;

	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

	for (ifp = ifnet; ifp; ifp = ifp->if_next) {
	if ((!(ifp->if_flags & IFF_RUNNING)) \|\|
	(ifp->if_flags & IFF_LOOPBACK))
	continue;

	/*
	* Look for entry already setup for this device
	*/
	for (nif = nif_head; nif; nif = nif->nf_next)
	if (nif->nf_ifp == ifp)
	break;
	if (nif)
	continue;

	if (ifp->if_output == ipl_if_output) {
	printf("IP Filter: ERROR INTF 0x%lx STILL ATTACHED\n",
	ifp);
	continue;
	}
	#if IPFDEBUG >= 4
	printf("IP Filter: nifattach nif %x opt %x\n",
	ifp, ifp->if_output);
	#endif
	KMALLOC(nif, nif_t *);
	if (!nif) {
	printf("IP Filter: malloc(%d) for nif_t failed\n",
	sizeof(nif_t));
	continue;
	}

	nif->nf_ifp = ifp;
	strncpy(nif->nf_name, ifp->if_name, sizeof(nif->nf_name));
	nif->nf_name[sizeof(nif->nf_name) - 1] = '\0';
	nif->nf_unit = ifp->if_unit;

	nif->nf_next = nif_head;
	nif_head = nif;

	/*
	* Activate any rules directly associated with this interface
	*/
	MUTEX_ENTER(&ipf_mutex);
	for (f = ipfilter[0][0]; f; f = f->fr_next) {
	if ((f->fr_ifa == (struct ifnet *)-1)) {
	if (f->fr_ifname[0] &&
	(GETUNIT(f->fr_ifname, 4) == ifp))
	f->fr_ifa = ifp;
	}
	}
	for (f = ipfilter[1][0]; f; f = f->fr_next) {
	if ((f->fr_ifa == (struct ifnet *)-1)) {
	if (f->fr_ifname[0] &&
	(GETUNIT(f->fr_ifname, 4) == ifp))
	f->fr_ifa = ifp;
	}
	}
	MUTEX_EXIT(&ipf_mutex);
	MUTEX_ENTER(&ipf_nat);
	for (np = nat_list; np; np = np->in_next) {
	if ((np->in_ifp == (void *)-1)) {
	if (np->in_ifname[0] &&
	(GETUNIT(np->in_ifname, 4) == ifp))
	np->in_ifp = (void *)ifp;
	}
	}
	MUTEX_EXIT(&ipf_nat);

	nif->nf_output = ifp->if_output;
	ifp->if_output = ipl_if_output;

	#if IPFDEBUG >= 4
	printf("IP Filter: nifattach: ifp(%lx)->if_output FROM %lx TO %lx\n",
	ifp, nif->nf_output, ifp->if_output);
	#endif

	printf("IP Filter: attach to [%s,%d]\n",
	nif->nf_name, ifp->if_unit);
	}
	if (!nif_head)
	printf("IP Filter: not attached to any interfaces\n");

	nif_interfaces = in_interfaces;

	MUTEX_EXIT(&ipfi_mutex);

	return;
	}

	/*
	* look for bad consistancies between the list of interfaces the filter knows
	* about and those which are currently configured.
	*/
	int
	ipfsync(void)
	{
	register struct frentry *f;
	register ipnat_t *np;
	register nif_t nif, *qp;
	register struct ifnet *ifp;

	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
	for (qp = &nif_head; (nif = *qp); ) {
	for (ifp = ifnet; ifp; ifp = ifp->if_next)
	if ((nif->nf_ifp == ifp) &&
	(nif->nf_unit == ifp->if_unit) &&
	!strcmp(nif->nf_name, ifp->if_name)) {
	break;
	}
	if (ifp) {
	qp = &nif->nf_next;
	continue;
	}
	printf("IP Filter: detaching [%s]\n", nif->nf_name);
	*qp = nif->nf_next;

	/*
	* Disable any rules directly associated with this interface
	*/
	MUTEX_ENTER(&ipf_mutex);
	for (f = ipfilter[0][0]; f; f = f->fr_next)
	if (f->fr_ifa == (void *)nif->nf_ifp)
	f->fr_ifa = (struct ifnet *)-1;
	for (f = ipfilter[1][0]; f; f = f->fr_next)
	if (f->fr_ifa == (void *)nif->nf_ifp)
	f->fr_ifa = (struct ifnet *)-1;
	MUTEX_EXIT(&ipf_mutex);
	MUTEX_ENTER(&ipf_nat);
	for (np = nat_list; np; np = np->in_next)
	if (np->in_ifp == (void *)nif->nf_ifp)
	np->in_ifp =(struct ifnet *)-1;
	MUTEX_EXIT(&ipf_nat);

	KFREE(nif);
	nif = *qp;
	}
	MUTEX_EXIT(&ipfi_mutex);

	nifattach();

	return 0;
	}


	/*
	* unhook the IP filter from all defined interfaces with IP addresses
	*/
	static void
	nifdetach()
	{
	struct ifnet *ifp;
	nif_t nif, *qp;

	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */
	/*
	* Make two passes, first get rid of all the unknown devices, next
	* unlink known devices.
	*/
	for (qp = &nif_head; (nif = *qp); ) {
	for (ifp = ifnet; ifp; ifp = ifp->if_next)
	if (nif->nf_ifp == ifp)
	break;
	if (ifp) {
	qp = &nif->nf_next;
	continue;
	}
	printf("IP Filter: removing [%s]\n", nif->nf_name);
	*qp = nif->nf_next;
	KFREE(nif);
	}

	while ((nif = nif_head)) {
	nif_head = nif->nf_next;
	for (ifp = ifnet; ifp; ifp = ifp->if_next)
	if (nif->nf_ifp == ifp)
	break;
	if (ifp) {
	printf("IP Filter: detaching [%s,%d]\n",
	nif->nf_name, ifp->if_unit);

	#if IPFDEBUG >= 4
	printf("IP Filter: nifdetach: ifp(%lx)->if_output FROM %lx TO %lx\n",
	ifp, ifp->if_output, nif->nf_output);
	#endif
	ifp->if_output = nif->nf_output;
	}
	KFREE(nif);
	}
	MUTEX_EXIT(&ipfi_mutex);

	return;
	}


	static void
	ipfilterdetach(void)
	{
	#ifdef IPFILTER_LKM
	MUTEX_ENTER(&ipfi_mutex); /* sets interrupt priority level to splhi */

	if (ipff_addr) {
	*ipff_addr = 0;

	if (ipfk_addr)
	bcopy(ipfk_code, ipfk_addr, sizeof(ipfk_code));

	*ipff_addr = ipff_value;
	}

	MUTEX_EXIT(&ipfi_mutex);
	#else
	extern int ipfilterflag;

	ipfilterflag = 0;
	#endif
	}

	/* called by ipldetach() */
	void
	ipfilter_sgi_detach(void)
	{
	nifdetach();

	ipfilterdetach();
	}

	/* called by iplattach() */
	int
	ipfilter_sgi_attach(void)
	{
	int error;

	nif_interfaces = 0;

	error = ipfilterattach();

	if (!error)
	nifattach();

	return error;
	}

	/* this function is called from ipfr_slowtimer at 500ms intervals to
	keep our interface list in sync */
	void
	ipfilter_sgi_intfsync(void)
	{
	MUTEX_ENTER(&ipfi_mutex);
	if (nif_interfaces != in_interfaces) {
	/* if the number of interfaces has changed, resync */
	MUTEX_EXIT(&ipfi_mutex);
	ipfsync();
	} else
	MUTEX_EXIT(&ipfi_mutex);
	}

	#ifdef IPFILTER_LKM
	/* this routine should be treated as an interrupt routine and should
	not call any routines that would cause it to sleep, such as: biowait(),
	sleep(), psema() or delay().
	*/
	int
	IPL_EXTERN(unload)(void)
	{
	int error = 0;

	error = ipldetach();

	LOCK_DEALLOC(ipl_mutex.l);
	LOCK_DEALLOC(ipf_rw.l);
	LOCK_DEALLOC(ipf_auth.l);
	LOCK_DEALLOC(ipf_natfrag.l);
	LOCK_DEALLOC(ipf_nat.l);
	LOCK_DEALLOC(ipf_state.l);
	LOCK_DEALLOC(ipf_frag.l);
	LOCK_DEALLOC(ipf_mutex.l);
	LOCK_DEALLOC(ipfi_mutex.l);

	return error;
	}
	#endif

	void
	IPL_EXTERN(init)(void)
	{
	#ifdef IPFILTER_LKM
	int error;
	#endif

	ipfi_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_frag.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_state.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_nat.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_natfrag.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_auth.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipf_rw.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);
	ipl_mutex.l = LOCK_ALLOC((uchar_t)-1, IPF_LOCK_PL, (lkinfo_t *)-1, KM_NOSLEEP);

	if (!ipfi_mutex.l \|\| !ipf_mutex.l \|\| !ipf_frag.l \|\| !ipf_state.l \|\|
	!ipf_nat.l \|\| !ipf_natfrag.l \|\| !ipf_auth.l \|\| !ipf_rw.l \|\|
	!ipl_mutex.l)
	panic("IP Filter: LOCK_ALLOC failed");

	#ifdef IPFILTER_LKM
	error = iplattach();
	if (error) {
	IPL_EXTERN(unload)();
	}
	#endif

	return;
	}