/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (C) 1999 Apple Computer, Inc.  */

/*
 * Support for Network Kernel Extensions: Socket Filters
 *
 * Justin C. Walker, 990319
 */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <machine/spl.h>
#include "kext_net.h"

/* List of kernel extensions (networking) known to kernel */
struct nf_list nf_list;

static int sockfilter_fix_symantec_bug(struct NFDescriptor* theirDesc);

/*
 * Register a global filter for the specified protocol
 * Make a few checks and then insert the new descriptor in the
 *  filter list and, if global, in its protosw's chain.
 */
int
register_sockfilter(struct NFDescriptor *nfp, struct NFDescriptor *nfp1,
		    struct protosw *pr, int flags)
{	int s;
	static int NF_initted = 0;

	if (nfp == NULL)
		return(EINVAL);

	/* Fix Symantec's broken NPC kext */
	if (nfp->nf_handle == 0xf1ab02de) {
		int err = sockfilter_fix_symantec_bug(nfp);
		if (err != 0)
			return err;
	}

	s = splhigh();
	if (!NF_initted)
	{	NF_initted = 1;
		TAILQ_INIT(&nf_list);
	}

	/*
	 * Install the extension:
	 * First, put it in the global list of all filters
	 * Then, if global, install in the protosw's list 
	 */
	TAILQ_INSERT_TAIL(&nf_list, nfp, nf_list);
	if (nfp->nf_flags & NFD_GLOBAL)
	{	if (flags & NFF_BEFORE)
		{	if (nfp1 == NULL)
			{	TAILQ_INSERT_HEAD(&pr->pr_sfilter,
						  nfp, nf_next);
			} else
				TAILQ_INSERT_BEFORE(nfp1, nfp, nf_next);
		} else		/* Default: AFTER */
		{	if (nfp1 == NULL)
			{	TAILQ_INSERT_TAIL(&pr->pr_sfilter,
						  nfp, nf_next);
			} else
				TAILQ_INSERT_AFTER(&pr->pr_sfilter, nfp1,
						   nfp, nf_next);
		}
	}
	splx(s);
	return(0);
}

int
unregister_sockfilter(struct NFDescriptor *nfp, struct protosw *pr, __unused int flags)
{	int s;

	s = splhigh();
	TAILQ_REMOVE(&nf_list, nfp, nf_list);
	/* Only globals are attached to the protosw entry */
	if (nfp->nf_flags & NFD_GLOBAL)
		TAILQ_REMOVE(&pr->pr_sfilter, nfp, nf_next);
	splx(s);
	return(0);
}

struct NFDescriptor *
find_nke(unsigned int handle)
{	struct NFDescriptor *nfp;

	nfp = nf_list.tqh_first;
	while (nfp)
	{	if (nfp->nf_handle == handle)
			return(nfp);
		nfp = nfp->nf_list.tqe_next;
	}
	return(NULL);
}

/*
 * Insert a previously registered, non-global, NKE into the list of
 *  active NKEs for this socket.  Then invoke its "attach/create" entry.
 * Assumed called with protection in place (spl/mutex/whatever)
 * XXX: How to which extension is not found, on error.
 */
int
nke_insert(struct socket *so, struct so_nke *np)
{
	struct kextcb *kp, *kp1;
	struct NFDescriptor *nf1, *nf2 = NULL;

	if (np->nke_where != NULL)
	{	if ((nf2 = find_nke(np->nke_where)) == NULL)
		{	/* ??? */
			return(ENXIO);/* XXX */
		}
	}

	if ((nf1 = find_nke(np->nke_handle)) == NULL)
	{	/* ??? */
		return(ENXIO);/* XXX */
	}

	kp = so->so_ext;
	kp1 = NULL;
        if (np->nke_flags & NFF_BEFORE)
	{	if (nf2)
		{       while (kp)
			{       if (kp->e_nfd == nf2)
					break;
				kp1 = kp;
				kp = kp->e_next;
			}
			if (kp == NULL)
				return(ENXIO);/* XXX */
		}
	} else
	{	if (nf2)
		{       while (kp)
			{       if (kp->e_nfd == nf2)
					break;
				kp1 = kp;
				kp = kp->e_next;
			}
			if (kp == NULL)
				return(ENXIO);/* XXX */
		}
		kp1 = kp;
	}
	/*
	 * Here with kp1 pointing to the insertion point.
	 * If null, this is first entry.
	 * Now, create and insert the descriptor.
	 */

	MALLOC(kp, struct kextcb *, sizeof(*kp), M_TEMP, M_WAITOK);
	if (kp == NULL)
		return(ENOBUFS); /* so_free will clean up */
	bzero(kp, sizeof (*kp));
	if (kp1 == NULL)
        {       kp->e_next = so->so_ext;
		so->so_ext = kp;
	} else
	{	kp->e_next = kp1->e_next;
		kp1->e_next = kp;
	}
	kp->e_fcb = NULL;
	kp->e_nfd = nf1;
	kp->e_soif = nf1->nf_soif;
	kp->e_sout = nf1->nf_soutil;
	/*
	 * Ignore return value for create
	 * Everyone gets a chance at startup
	 */
	if (kp->e_soif && kp->e_soif->sf_socreate)
		(*kp->e_soif->sf_socreate)(so, so->so_proto, kp);
	return(0);
}

/*
 * The following gunk is a fix for Symantec's broken NPC kext
 * Symantec's NPC kext does not check that the kextcb->e_fcb
 * is not NULL before derefing it. The result is a panic in
 * the very few cases where the e_fcb is actually NULL.
 *
 * This gross chunk of code copies the old function ptrs
 * supplied by the kext and wraps a few select ones in
 * our own functions that just check for NULL before
 * calling in to the kext.
 */

static struct sockif*	g_symantec_if_funcs = NULL;
static struct sockutil*	g_symantec_util_funcs = NULL;
static int sym_fix_sbflush(struct sockbuf *, struct kextcb *);
static int sym_fix_sbappend(struct sockbuf *, struct mbuf *, struct kextcb *);
static int sym_fix_soclose(struct socket *, struct kextcb *);
static int sym_fix_sofree(struct socket *, struct kextcb *);
static int sym_fix_soconnect(struct socket *, struct sockaddr *, struct kextcb *);
static int sym_fix_soisconnected(struct socket *, struct kextcb *);
static int sym_fix_sosend(struct socket *, struct sockaddr **, struct uio **, struct mbuf **,
			struct mbuf **, int *, struct kextcb *);
static int sym_fix_socantrcvmore(struct socket *, struct kextcb *);
static int sym_fix_socontrol(struct socket *, struct sockopt *, struct kextcb *);

static int sockfilter_fix_symantec_bug(struct NFDescriptor* theirDesc)
{
	if (!g_symantec_if_funcs ) {
		MALLOC(g_symantec_if_funcs, struct sockif*, sizeof(*g_symantec_if_funcs), M_TEMP, M_WAITOK);
		
		if (!g_symantec_if_funcs)
			return ENOMEM;
		
		*g_symantec_if_funcs = *theirDesc->nf_soif;
	}
	
	if (!g_symantec_util_funcs) {
		MALLOC(g_symantec_util_funcs, struct sockutil*, sizeof(*g_symantec_util_funcs), M_TEMP, M_WAITOK);
		
		if (!g_symantec_util_funcs)
			return ENOMEM;
		
		*g_symantec_util_funcs = *theirDesc->nf_soutil;
	}
	
	if (theirDesc->nf_soutil->su_sbflush)
		theirDesc->nf_soutil->su_sbflush = sym_fix_sbflush;
	if (theirDesc->nf_soutil->su_sbappend)
		theirDesc->nf_soutil->su_sbappend = sym_fix_sbappend;
	if (theirDesc->nf_soif->sf_soclose)
		theirDesc->nf_soif->sf_soclose = sym_fix_soclose;
	if (theirDesc->nf_soif->sf_sofree)
		theirDesc->nf_soif->sf_sofree = sym_fix_sofree;
	if (theirDesc->nf_soif->sf_soconnect)
		theirDesc->nf_soif->sf_soconnect = sym_fix_soconnect;
	if (theirDesc->nf_soif->sf_soisconnected)
		theirDesc->nf_soif->sf_soisconnected = sym_fix_soisconnected;
	if (theirDesc->nf_soif->sf_sosend)
		theirDesc->nf_soif->sf_sosend = sym_fix_sosend;
	if (theirDesc->nf_soif->sf_socantrcvmore)
		theirDesc->nf_soif->sf_socantrcvmore = sym_fix_socantrcvmore;
	if (theirDesc->nf_soif->sf_socontrol)
		theirDesc->nf_soif->sf_socontrol = sym_fix_socontrol;
	
	return 0;
}

static int sym_fix_sbflush(struct sockbuf *p1, struct kextcb *p2)
{
	if (p2->e_fcb != NULL && g_symantec_util_funcs)
		return g_symantec_util_funcs->su_sbflush(p1, p2);
	else
		return 0;
}

static int sym_fix_sbappend(struct sockbuf *p1, struct mbuf *p2, struct kextcb *p3)
{
	if (p3->e_fcb != NULL && g_symantec_util_funcs)
		return g_symantec_util_funcs->su_sbappend(p1, p2, p3);
	else
		return 0;
}

static int sym_fix_soclose(struct socket *p1, struct kextcb *p2)
{
	if (p2->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_soclose(p1, p2);
	else
		return 0;
}

static int sym_fix_sofree(struct socket *p1, struct kextcb *p2)
{
	if (p2->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_sofree(p1, p2);
	else
		return 0;
}

static int sym_fix_soconnect(struct socket *p1, struct sockaddr *p2, struct kextcb *p3)
{
	if (p3->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_soconnect(p1, p2, p3);
	else
		return 0;
}

static int sym_fix_soisconnected(struct socket *p1, struct kextcb *p2)
{
	if (p2->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_soisconnected(p1, p2);
	else
		return 0;
}

static int sym_fix_sosend(struct socket *p1, struct sockaddr **p2, struct uio **p3, struct mbuf **p4,
			struct mbuf **p5, int *p6, struct kextcb *p7)
{
	if (p7->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_sosend(p1, p2, p3, p4, p5, p6, p7);
	else
		return 0;
}

static int sym_fix_socantrcvmore(struct socket *p1, struct kextcb *p2)
{
	if (p2->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_socantrcvmore(p1, p2);
	else
		return 0;
}

static int sym_fix_socontrol(struct socket *p1, struct sockopt *p2, struct kextcb *p3)
{
	if (p3->e_fcb != NULL && g_symantec_if_funcs)
		return g_symantec_if_funcs->sf_socontrol(p1, p2, p3);
	else
		return 0;
}