radij.c

This a good VPN source

char radij_c_version[] = "RCSID $Id: radij.c,v 1.47 2004/07/10 19:11:18 mcr Exp $";

/*
 * This file is defived from ${SRC}/sys/net/radix.c of BSD 4.4lite
 *
 * Variable and procedure names have been modified so that they don't
 * conflict with the original BSD code, as a small number of modifications
 * have been introduced and we may want to reuse this code in BSD.
 * 
 * The `j' in `radij' is pronounced as a voiceless guttural (like a Greek
 * chi or a German ch sound (as `doch', not as in `milch'), or even a 
 * spanish j as in Juan.  It is not as far back in the throat like
 * the corresponding Hebrew sound, nor is it a soft breath like the English h.
 * It has nothing to do with the Dutch ij sound.
 * 
 * Here is the appropriate copyright notice:
 */

/*
 * Copyright (c) 1988, 1989, 1993
 *	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 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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 BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)radix.c	8.2 (Berkeley) 1/4/94
 */

/*
 * Routines to build and maintain radix trees for routing lookups.
 */

#include <linux/config.h>
#include <linux/version.h>
#include <linux/kernel.h> /* printk() */

#include "openswan/ipsec_param.h"

#ifdef MALLOC_SLAB
# include <linux/slab.h> /* kmalloc() */
#else /* MALLOC_SLAB */
# include <linux/malloc.h> /* kmalloc() */
#endif /* MALLOC_SLAB */
#include <linux/errno.h>  /* error codes */
#include <linux/types.h>  /* size_t */
#include <linux/interrupt.h> /* mark_bh */

#include <linux/netdevice.h>   /* struct device, and other headers */
#include <linux/etherdevice.h> /* eth_type_trans */
#include <linux/ip.h>          /* struct iphdr */
#include <linux/skbuff.h>
#ifdef NET_21
# include <asm/uaccess.h>
# include <linux/in6.h>
#endif /* NET_21 */
#include <asm/checksum.h>
#include <net/ip.h>

#include <openswan.h>

#include "openswan/radij.h"
#include "openswan/ipsec_encap.h"
#include "openswan/ipsec_radij.h"

int	maj_keylen;
struct radij_mask *rj_mkfreelist;
struct radij_node_head *mask_rjhead;
static int gotOddMasks;
static char *maskedKey;
static char *rj_zeroes, *rj_ones;

#define rj_masktop (mask_rjhead->rnh_treetop)
#ifdef Bcmp
# undef Bcmp
#endif /* Bcmp */
#define Bcmp(a, b, l) (l == 0 ? 0 : memcmp((caddr_t)(b), (caddr_t)(a), (size_t)l))
/*
 * The data structure for the keys is a radix tree with one way
 * branching removed.  The index rj_b at an internal node n represents a bit
 * position to be tested.  The tree is arranged so that all descendants
 * of a node n have keys whose bits all agree up to position rj_b - 1.
 * (We say the index of n is rj_b.)
 *
 * There is at least one descendant which has a one bit at position rj_b,
 * and at least one with a zero there.
 *
 * A route is determined by a pair of key and mask.  We require that the
 * bit-wise logical and of the key and mask to be the key.
 * We define the index of a route to associated with the mask to be
 * the first bit number in the mask where 0 occurs (with bit number 0
 * representing the highest order bit).
 * 
 * We say a mask is normal if every bit is 0, past the index of the mask.
 * If a node n has a descendant (k, m) with index(m) == index(n) == rj_b,
 * and m is a normal mask, then the route applies to every descendant of n.
 * If the index(m) < rj_b, this implies the trailing last few bits of k
 * before bit b are all 0, (and hence consequently true of every descendant
 * of n), so the route applies to all descendants of the node as well.
 *
 * The present version of the code makes no use of normal routes,
 * but similar logic shows that a non-normal mask m such that
 * index(m) <= index(n) could potentially apply to many children of n.
 * Thus, for each non-host route, we attach its mask to a list at an internal
 * node as high in the tree as we can go. 
 */

struct radij_node *
rj_search(v_arg, head)
	void *v_arg;
	struct radij_node *head;
{
	register struct radij_node *x;
	register caddr_t v;

	for (x = head, v = v_arg; x->rj_b >= 0;) {
		if (x->rj_bmask & v[x->rj_off])
			x = x->rj_r;
		else
			x = x->rj_l;
	}
	return (x);
};

struct radij_node *
rj_search_m(v_arg, head, m_arg)
	struct radij_node *head;
	void *v_arg, *m_arg;
{
	register struct radij_node *x;
	register caddr_t v = v_arg, m = m_arg;

	for (x = head; x->rj_b >= 0;) {
		if ((x->rj_bmask & m[x->rj_off]) &&
		    (x->rj_bmask & v[x->rj_off]))
			x = x->rj_r;
		else
			x = x->rj_l;
	}
	return x;
};

int
rj_refines(m_arg, n_arg)
	void *m_arg, *n_arg;
{
	register caddr_t m = m_arg, n = n_arg;
	register caddr_t lim, lim2 = lim = n + *(u_char *)n;
	int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
	int masks_are_equal = 1;

	if (longer > 0)
		lim -= longer;
	while (n < lim) {
		if (*n & ~(*m))
			return 0;
		if (*n++ != *m++)
			masks_are_equal = 0;
			
	}
	while (n < lim2)
		if (*n++)
			return 0;
	if (masks_are_equal && (longer < 0))
		for (lim2 = m - longer; m < lim2; )
			if (*m++)
				return 1;
	return (!masks_are_equal);
}


struct radij_node *
rj_match(v_arg, head)
	void *v_arg;
	struct radij_node_head *head;
{
	caddr_t v = v_arg;
	register struct radij_node *t = head->rnh_treetop, *x;
	register caddr_t cp = v, cp2, cp3;
	caddr_t cplim, mstart;
	struct radij_node *saved_t, *top = t;
	int off = t->rj_off, vlen = *(u_char *)cp, matched_off;

	/*
	 * Open code rj_search(v, top) to avoid overhead of extra
	 * subroutine call.
	 */
	for (; t->rj_b >= 0; ) {
		if (t->rj_bmask & cp[t->rj_off])
			t = t->rj_r;
		else
			t = t->rj_l;
	}
	/*
	 * See if we match exactly as a host destination
	 */
	KLIPS_PRINT(debug_radij,
		    "klips_debug:rj_match: "
		    "* See if we match exactly as a host destination\n");
	
	cp += off; cp2 = t->rj_key + off; cplim = v + vlen;
	for (; cp < cplim; cp++, cp2++)
		if (*cp != *cp2)
			goto on1;
	/*
	 * This extra grot is in case we are explicitly asked
	 * to look up the default.  Ugh!
	 */
	if ((t->rj_flags & RJF_ROOT) && t->rj_dupedkey)
		t = t->rj_dupedkey;
	return t;
on1:
	matched_off = cp - v;
	saved_t = t;
	KLIPS_PRINT(debug_radij,
		    "klips_debug:rj_match: "
		    "** try to match a leaf, t=0p%p\n", t);
	do {
	    if (t->rj_mask) {
		/*
		 * Even if we don't match exactly as a hosts;
		 * we may match if the leaf we wound up at is
		 * a route to a net.
		 */
		cp3 = matched_off + t->rj_mask;
		cp2 = matched_off + t->rj_key;
		for (; cp < cplim; cp++)
			if ((*cp2++ ^ *cp) & *cp3++)
				break;
		if (cp == cplim)
			return t;
		cp = matched_off + v;
	    }
	} while ((t = t->rj_dupedkey));
	t = saved_t;
	/* start searching up the tree */
	KLIPS_PRINT(debug_radij,
		    "klips_debug:rj_match: "
		    "*** start searching up the tree, t=0p%p\n",
		    t);
	do {
		register struct radij_mask *m;
		
		t = t->rj_p;
		KLIPS_PRINT(debug_radij,
			    "klips_debug:rj_match: "
			    "**** t=0p%p\n",
			    t);
		if ((m = t->rj_mklist)) {
			/*
			 * After doing measurements here, it may
			 * turn out to be faster to open code
			 * rj_search_m here instead of always
			 * copying and masking.
			 */
			/* off = min(t->rj_off, matched_off); */
			off = t->rj_off;
			if (matched_off < off)
				off = matched_off;
			mstart = maskedKey + off;
			do {
				cp2 = mstart;
				cp3 = m->rm_mask + off;
				KLIPS_PRINT(debug_radij,
					    "klips_debug:rj_match: "
					    "***** cp2=0p%p cp3=0p%p\n",
					    cp2, cp3);
				for (cp = v + off; cp < cplim;)
					*cp2++ =  *cp++ & *cp3++;
				x = rj_search(maskedKey, t);
				while (x && x->rj_mask != m->rm_mask)
					x = x->rj_dupedkey;
				if (x &&
				    (Bcmp(mstart, x->rj_key + off,
					vlen - off) == 0))
					    return x;
			} while ((m = m->rm_mklist));
		}
	} while (t != top);
	KLIPS_PRINT(debug_radij,
		    "klips_debug:rj_match: "
		    "***** not found.\n");
	return 0;
};
		
#ifdef RJ_DEBUG
int	rj_nodenum;
struct	radij_node *rj_clist;
int	rj_saveinfo;
DEBUG_NO_STATIC void traverse(struct radij_node *);
#ifdef RJ_DEBUG2
int	rj_debug =  1;
#else
int	rj_debug =  0;
#endif /* RJ_DEBUG2 */
#endif /* RJ_DEBUG */

struct radij_node *
rj_newpair(v, b, nodes)
	void *v;
	int b;
	struct radij_node nodes[2];
{
	register struct radij_node *tt = nodes, *t = tt + 1;
	t->rj_b = b; t->rj_bmask = 0x80 >> (b & 7);
	t->rj_l = tt; t->rj_off = b >> 3;
	tt->rj_b = -1; tt->rj_key = (caddr_t)v; tt->rj_p = t;
	tt->rj_flags = t->rj_flags = RJF_ACTIVE;
#ifdef RJ_DEBUG
	tt->rj_info = rj_nodenum++; t->rj_info = rj_nodenum++;
	tt->rj_twin = t; tt->rj_ybro = rj_clist; rj_clist = tt;
#endif /* RJ_DEBUG */
	return t;
}

struct radij_node *
rj_insert(v_arg, head, dupentry, nodes)
	void *v_arg;
	struct radij_node_head *head;
	int *dupentry;
	struct radij_node nodes[2];
{
	caddr_t v = v_arg;
	struct radij_node *top = head->rnh_treetop;
	int head_off = top->rj_off, vlen = (int)*((u_char *)v);
	register struct radij_node *t = rj_search(v_arg, top);
	register caddr_t cp = v + head_off;
	register int b;
	struct radij_node *tt;
    	/*
	 *find first bit at which v and t->rj_key differ
	 */
    {
	register caddr_t cp2 = t->rj_key + head_off;
	register int cmp_res;
	caddr_t cplim = v + vlen;

	while (cp < cplim)
		if (*cp2++ != *cp++)
			goto on1;
	*dupentry = 1;
	return t;
on1:
	*dupentry = 0;
	cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
	for (b = (cp - v) << 3; cmp_res; b--)
		cmp_res >>= 1;
    }
    {
	register struct radij_node *p, *x = top;
	cp = v;
	do {
		p = x;
		if (cp[x->rj_off] & x->rj_bmask) 
			x = x->rj_r;
		else x = x->rj_l;
	} while (b > (unsigned) x->rj_b); /* x->rj_b < b && x->rj_b >= 0 */
#ifdef RJ_DEBUG
	if (rj_debug)
		printk("klips_debug:rj_insert: Going In:\n"), traverse(p);
#endif /* RJ_DEBUG */
	t = rj_newpair(v_arg, b, nodes); tt = t->rj_l;
	if ((cp[p->rj_off] & p->rj_bmask) == 0)
		p->rj_l = t;
	else
		p->rj_r = t;
	x->rj_p = t; t->rj_p = p; /* frees x, p as temp vars below */
	if ((cp[t->rj_off] & t->rj_bmask) == 0) {
		t->rj_r = x;
	} else {
		t->rj_r = tt; t->rj_l = x;
	}
#ifdef RJ_DEBUG
	if (rj_debug)
		printk("klips_debug:rj_insert: Coming out:\n"), traverse(p);
#endif /* RJ_DEBUG */
    }
	return (tt);
}

struct radij_node *
rj_addmask(n_arg, search, skip)
	int search, skip;
	void *n_arg;
{
	caddr_t netmask = (caddr_t)n_arg;