patch-2.1.30 linux/net/ipv6/ip6_fib.c

• Lines: 928
• Date: Thu Mar 20 18:17:15 1997
• Orig file: v2.1.29/linux/net/ipv6/ip6_fib.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.29/linux/net/ipv6/ip6_fib.c linux/net/ipv6/ip6_fib.c
@@ -0,0 +1,927 @@
+/*
+ *	Linux INET6 implementation 
+ *	Forwarding Information Database
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>	
+ *
+ *	$Id: ip6_fib.c,v 1.6 1997/03/18 18:24:33 davem Exp $
+ *
+ *	This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/route.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+
+#ifdef 	CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#endif
+
+#include <net/ipv6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/netlink.h>
+
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+
+#define RT_DEBUG 2
+
+struct rt6_statistics	rt6_stats;
+
+/*
+ *	A routing update causes an increase of the serial number on the
+ *	afected subtree. This allows for cached routes to be asynchronously
+ *	tested when modifications are made to the destination cache as a
+ *	result of redirects, path MTU changes, etc.
+ */
+
+static __u32	rt_sernum	= 0;
+
+static void fib6_run_gc(unsigned long);
+
+static struct timer_list ip6_fib_timer = {
+	NULL, NULL,
+	0,
+	0,
+	fib6_run_gc
+};
+
+/*
+ *	Auxiliary address test functions for the radix tree.
+ *
+ *	These assume a 32bit processor (although it will work on 
+ *	64bit processors)
+ */
+
+/*
+ *	compare "prefix length" bits of an address
+ */
+
+static __inline__ int addr_match(void *token1, void *token2, int prefixlen)
+{
+	__u32 *a1 = token1;
+	__u32 *a2 = token2;
+	int pdw;
+	int pbi;
+
+	pdw = prefixlen >> 0x05;  /* num of whole __u32 in prefix */
+	pbi = prefixlen &  0x1f;  /* num of bits in incomplete u32 in prefix */
+
+	if (pdw)
+		if (memcmp(a1, a2, pdw << 2))
+			return 0;
+
+	if (pbi) {
+		__u32 w1, w2;
+		__u32 mask;
+
+		w1 = a1[pdw];
+		w2 = a2[pdw];
+
+		mask = htonl((0xffffffff) << (0x20 - pbi));
+
+		if ((w1 ^ w2) & mask)
+			return 0;
+	}
+
+	return 1;
+}
+
+/*
+ *	test bit
+ */
+
+static __inline__ int addr_bit_set(void *token, int fn_bit)
+{
+	int dw;
+	__u32 b1;
+	__u32 mask;
+	int bit = fn_bit;
+	__u32 *addr = token;
+
+	dw = bit >> 0x05;
+
+	b1 = addr[dw];
+	
+	bit = ~bit;
+	bit &= 0x1f;
+	mask = htonl(1 << bit);
+	return (b1 & mask);
+}
+
+
+
+/*
+ *	find the first different bit between two addresses
+ *	length of address must be a multiple of 32bits
+ */
+
+static __inline__ int addr_diff(void *token1, void *token2, int addrlen)
+{
+	__u32 *a1 = token1;
+	__u32 *a2 = token2;
+	int i;
+
+	addrlen >>= 2;
+
+	for (i = 0; i < addrlen; i++) {
+		__u32 b1, b2;
+		__u32 xb;
+
+		b1 = a1[i];
+		b2 = a2[i];
+
+		xb = b1 ^ b2;
+
+		if (xb) {
+			int res = 0;
+			int j=31;
+
+			xb = ntohl(xb);
+
+			while (test_bit(j, &xb) == 0) {
+				res++;
+				j--;
+			}
+
+			return (i * 32 + res);
+		}
+	}
+
+	/*
+	 *	we should *never* get to this point since that 
+	 *	would mean the addrs are equal
+	 */
+
+	return -1;
+}
+
+static __inline__ struct fib6_node * node_alloc(void)
+{
+	struct fib6_node *fn;
+
+	if ((fn = kmalloc(sizeof(struct fib6_node), GFP_ATOMIC))) {
+		memset(fn, 0, sizeof(struct fib6_node));
+		rt6_stats.fib_nodes++;
+	}
+
+	return fn;
+}
+
+static __inline__ void node_free(struct fib6_node * fn)
+{
+	rt6_stats.fib_nodes--;
+	kfree(fn);
+}
+
+/*
+ *	Routing Table
+ *
+ *	return the apropriate node for a routing tree "add" operation
+ *	by either creating and inserting or by returning an existing
+ *	node.
+ */
+
+static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
+				     int addrlen, int plen,
+				     unsigned long offset,
+				     struct rt6_info *rt)
+				     
+{
+	struct fib6_node *fn;
+	struct fib6_node *pn = NULL;
+	struct fib6_node *in;
+	struct fib6_node *ln;
+	struct rt6key *key;
+	__u32	bit;
+	__u32	dir = 0;
+	__u32	sernum = ++rt_sernum;
+
+	/* insert node in tree */
+
+	fn = root;
+
+	if (plen == 0)
+		return fn;
+
+	for (;;) {
+		if (fn == NULL) {
+			ln = node_alloc();
+
+			if (ln == NULL)
+				return NULL;
+			ln->fn_bit = plen;
+			
+			ln->parent = pn;
+			ln->fn_sernum = sernum;
+			rt->rt6i_node = ln;
+
+			if (dir)
+				pn->right = ln;
+			else
+				pn->left  = ln;
+
+			return ln;
+		}
+
+		key = (struct rt6key *)((u8 *)fn->leaf + offset);
+
+		if (addr_match(&key->addr, addr, fn->fn_bit)) {
+			if (plen == fn->fn_bit) {
+				/* clean up an intermediate node */
+				if ((fn->fn_flags & RTN_RTINFO) == 0) {
+					rt6_release(fn->leaf);
+					fn->leaf = NULL;
+				}
+			
+				fn->fn_sernum = sernum;
+				
+				return fn;
+			}
+
+			if (plen > fn->fn_bit) {
+				/* Walk down on tree. */
+				fn->fn_sernum = sernum;
+				dir = addr_bit_set(addr, fn->fn_bit);
+				pn = fn;
+				fn = dir ? fn->right: fn->left;
+
+				continue;
+			}
+		}
+
+		/*
+		 * split since we don't have a common prefix anymore or 
+		 * we have a less significant route.
+		 * we've to insert an intermediate node on the list
+		 * this new node will point to the one we need to create
+		 * and the current
+		 */
+
+		pn = fn->parent;
+
+		/* find 1st bit in difference between the 2 addrs */
+		bit = addr_diff(addr, &key->addr, addrlen);
+
+
+		/* 
+		 *		(intermediate)	
+		 *	          /	   \
+		 *	(new leaf node)    (old node)
+		 */
+		if (plen > bit) {
+			in = node_alloc();
+		
+			if (in == NULL)
+				return NULL;
+
+			/* 
+			 * new intermediate node. 
+			 * RTN_RTINFO will
+			 * be off since that an address that chooses one of
+			 * the branches would not match less specific routes
+			 * int the other branch
+			 */
+
+			in->fn_bit = bit;
+
+			in->parent = pn;
+			in->leaf = rt;
+
+			in->fn_sernum = sernum;
+			atomic_inc(&rt->rt6i_ref);
+
+			/* leaf node */
+			ln = node_alloc();
+
+			if (ln == NULL) {
+				node_free(in);
+				return NULL;
+			}
+
+			/* update parent pointer */
+			if (dir)
+				pn->right = in;
+			else
+				pn->left  = in;
+
+			ln->fn_bit = plen;
+
+			ln->parent = in;
+			fn->parent = in;
+
+			ln->fn_sernum = sernum;
+
+			if (addr_bit_set(addr, bit)) {
+				in->right = ln;
+				in->left  = fn;
+			} else {
+				in->left  = ln;
+				in->right = fn;
+			}
+
+			return ln;
+		}
+
+		/* 
+		 *		(new leaf node)
+		 *	          /	   \
+		 *	     (old node)    NULL
+		 */
+
+		ln = node_alloc();
+
+		if (ln == NULL)
+			return NULL;
+
+		ln->fn_bit = plen;
+
+		ln->parent = pn;
+
+		ln->fn_sernum = sernum;
+		
+		if (dir)
+			pn->right = ln;
+		else
+			pn->left  = ln;
+		
+
+		if (addr_bit_set(&key->addr, plen))
+			ln->right = fn;
+		else
+			ln->left  = fn;
+
+		fn->parent = ln;
+
+		return ln;
+	}
+
+	return NULL;
+}
+
+/*
+ *	Insert routing information in a node.
+ */
+
+static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt)
+{
+	struct rt6_info *iter = NULL;
+	struct rt6_info **ins;
+
+	rt->rt6i_node = fn;
+	ins = &fn->leaf;
+
+	for (iter = fn->leaf; iter; iter=iter->u.next) {
+		/*
+		 *	Search for duplicates
+		 */
+
+		if (iter->rt6i_metric == rt->rt6i_metric) {
+			/*
+			 *	Same priority level
+			 */
+
+			if ((iter->rt6i_dev == rt->rt6i_dev) &&
+			    (iter->rt6i_flowr == rt->rt6i_flowr) &&
+			    (ipv6_addr_cmp(&iter->rt6i_gateway,
+					   &rt->rt6i_gateway) == 0))
+				return -EEXIST;
+		}
+
+		if (iter->rt6i_metric > rt->rt6i_metric)
+			break;
+
+		ins = &iter->u.next;
+	}
+
+	/*
+	 *	insert node
+	 */
+
+	*ins = rt;
+	rt->u.next = iter;
+	atomic_inc(&rt->rt6i_ref);
+	rt6_stats.fib_rt_entries++;
+
+	if ((fn->fn_flags & RTN_RTINFO) == 0) {
+		rt6_stats.fib_route_nodes++;
+		fn->fn_flags |= RTN_RTINFO;
+	}
+
+	return 0;
+}
+
+static __inline__ void fib6_start_gc(struct rt6_info *rt)
+{
+	if ((ip6_fib_timer.expires == 0) &&
+	    (rt->rt6i_flags & (RTF_ADDRCONF | RTF_CACHE))) {
+		ip6_fib_timer.expires = jiffies + ipv6_config.rt_gc_period;
+		add_timer(&ip6_fib_timer);
+	}
+}
+
+/*
+ *	Add routing information to the routing tree.
+ *	<destination addr>/<source addr>
+ *	with source addr info in sub-trees
+ */
+
+int fib6_add(struct fib6_node *root, struct rt6_info *rt)
+{
+	struct fib6_node *fn;
+	int err = -ENOMEM;
+	unsigned long offset;
+	
+	offset = (u8*) &rt->rt6i_dst - (u8*) rt;
+	fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
+			rt->rt6i_dst.plen, offset, rt);
+
+	if (fn == NULL) {
+#if RT_DEBUG >= 2
+		printk(KERN_DEBUG "fib6_add: fn == NULL\n");
+#endif
+		goto out;
+	}
+
+	if (rt->rt6i_src.plen) {
+		struct fib6_node *sn;
+
+#if RT_DEBUG >= 2
+		printk(KERN_DEBUG "fib6_add: src.len > 0\n");
+#endif
+
+		if (fn->subtree == NULL) {
+			struct fib6_node *sfn;
+
+			if (fn->leaf == NULL) {
+				fn->leaf = rt;
+				atomic_inc(&rt->rt6i_ref);
+			}
+
+			sfn = node_alloc();
+
+			if (sfn == NULL)
+				goto out;
+
+			sfn->parent = fn;
+			sfn->leaf = &ip6_null_entry;
+			sfn->fn_flags = RTN_ROOT;
+			sfn->fn_sernum = ++rt_sernum;
+
+			fn->subtree = sfn;
+		}
+
+		offset = (u8*) &rt->rt6i_src - (u8*) rt;
+
+		sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
+				sizeof(struct in6_addr), rt->rt6i_src.plen,
+				offset, rt);
+
+		if (sn == NULL)
+			goto out;
+
+		fn = sn;
+	}
+
+	err = fib6_add_rt2node(fn, rt);
+
+	if (err == 0)
+		fib6_start_gc(rt);
+out:
+	return err;
+}
+
+/*
+ *	Routing tree lookup
+ *
+ */
+
+struct lookup_args {
+	unsigned long	offset;		/* key offset on rt6_info	*/
+	struct in6_addr	*addr;		/* search key			*/
+};
+
+static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
+					struct lookup_args *args)
+{
+	struct fib6_node *fn;
+	int dir;
+
+	/*
+	 *	Descend on a tree
+	 */
+
+	fn = root;
+
+	for (;;) {
+		struct fib6_node *next;
+
+		dir = addr_bit_set(args->addr, fn->fn_bit);
+
+		next = dir ? fn->right : fn->left;
+
+		if (next) {
+			fn = next;
+			continue;
+		}
+
+		break;
+	}
+
+	while ((fn->fn_flags & RTN_ROOT) == 0) {
+		if (fn->subtree) {
+			struct fib6_node *st;
+			struct lookup_args *narg;
+
+			narg = args + 1;
+
+			if (narg->addr) {
+				st = fib6_lookup_1(fn->subtree, narg);
+
+				if (!(st->fn_flags & RTN_ROOT))
+				{
+					return st;
+				}
+			}
+		}
+
+		if (fn->fn_flags & RTN_RTINFO) {
+			struct rt6key *key;
+
+			key = (struct rt6key *) ((u8 *) fn->leaf +
+						 args->offset);
+
+			if (addr_match(&key->addr, args->addr, key->plen))
+				return fn;
+		}
+
+		fn = fn->parent;
+	}
+
+	return NULL;
+}
+
+struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
+			       struct in6_addr *saddr)
+{
+	struct lookup_args args[2];
+	struct rt6_info *rt = NULL;
+	struct fib6_node *fn;
+
+	args[0].offset = (u8*) &rt->rt6i_dst - (u8*) rt;
+	args[0].addr = daddr;
+
+	args[1].offset = (u8*) &rt->rt6i_src - (u8*) rt;
+	args[1].addr = saddr;
+
+	fn = fib6_lookup_1(root, args);
+
+	if (fn == NULL)
+		fn = root;
+
+	return fn;
+}
+
+/*
+ *	Deletion
+ *
+ */
+
+static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
+{
+	while(fn) {
+		if(fn->left)
+			return fn->left->leaf;
+
+		if(fn->right)
+			return fn->right->leaf;
+
+		fn = fn->subtree;
+	}
+	return NULL;
+}
+
+/*
+ *	called to trim the tree of intermediate nodes when possible
+ */
+
+static void fib6_del_2(struct fib6_node *fn)
+{
+	struct rt6_info *rt;
+
+	fn->fn_flags &= ~RTN_RTINFO;
+	rt6_stats.fib_route_nodes--;
+
+	if (fn->fn_flags & RTN_TL_ROOT)
+		return;
+
+	do {
+		struct fib6_node *pn, *child;
+		int children = 0;
+
+		child = NULL;
+
+		if (fn->left) {
+			children++;
+			child = fn->left;
+		}
+
+		if (fn->right) {
+			children++;
+			child = fn->right;
+		}
+
+		if (children > 1 || (fn->fn_flags & RTN_RTINFO))
+			break;
+
+		if (fn->subtree)
+			goto stree_node;
+
+		pn = fn->parent;
+
+		if ((fn->fn_flags & RTN_ROOT) == 0) {
+			if (pn->left == fn)
+				pn->left = child;
+			else
+				pn->right = child;
+
+			if (child)
+				child->parent = pn;
+
+			if (fn->leaf)
+				rt6_release(fn->leaf);
+		} else {
+			if (children)
+				break;
+
+			pn->subtree = NULL;
+		}
+
+		node_free(fn);
+		fn = pn;
+
+	} while (!(fn->fn_flags & RTN_TL_ROOT));
+
+	return;
+
+stree_node:
+
+	rt6_release(fn->leaf);
+	rt = fib6_find_prefix(fn);
+
+	if (rt == NULL)
+		panic("fib6_del_2: inconsistent tree\n");
+
+	atomic_inc(&rt->rt6i_ref);
+	fn->leaf = rt;
+}
+
+static struct fib6_node * fib6_del_1(struct rt6_info *rt)
+{
+	struct fib6_node *fn;
+	
+	fn = rt->rt6i_node;
+
+	if (fn) {
+		struct rt6_info **back;
+		struct rt6_info *lf;
+
+		back = &fn->leaf;
+		
+		for(lf = fn->leaf; lf; lf=lf->u.next) {
+			if (rt == lf) {
+				/*
+				 *	Delete this entry.
+				 */
+
+				*back = lf->u.next;
+				rt6_release(lf);
+				return fn;
+			}
+			back = &lf->u.next;
+		}
+	}
+
+	return NULL;
+}
+
+int fib6_del(struct rt6_info *rt)
+{
+	struct fib6_node *fn;
+
+	fn = fib6_del_1(rt);
+
+	if (fn == NULL)
+		return -ENOENT;
+
+	if (fn->leaf == NULL)
+		fib6_del_2(fn);
+
+	return 0;
+}
+
+/*
+ *	Tree transversal function
+ *
+ */
+
+void fib6_walk_tree(struct fib6_node *root, f_pnode func, void *arg,
+		    int filter)
+{
+	struct fib6_node *fn;
+
+	fn = root;
+	
+	do {
+		if (!(fn->fn_flags & RTN_TAG)) {
+			fn->fn_flags |= RTN_TAG;
+			
+			if (fn->left) {
+				fn = fn->left;
+				continue;
+			}
+		}
+
+		fn->fn_flags &= ~RTN_TAG;
+
+		if (fn->right) {
+			fn = fn->right;
+			continue;
+		}
+		
+		do {
+			struct fib6_node *node;
+			
+			if (fn->fn_flags & RTN_ROOT)
+				break;
+			node = fn;
+			fn = fn->parent;
+			
+			if (!(node->fn_flags & RTN_TAG)) {
+				if (node->subtree) {
+					fib6_walk_tree(node->subtree, func,
+						       arg, filter);
+				}
+
+				if (!filter ||
+				    (node->fn_flags & RTN_RTINFO))
+					(*func)(node, arg);
+			}
+			
+		} while (!(fn->fn_flags & RTN_TAG));
+
+	} while (!(fn->fn_flags & RTN_ROOT) || (fn->fn_flags & RTN_TAG));
+}
+
+/*
+ *	Garbage collection
+ */
+
+static int fib6_gc_node(struct fib6_node *fn, int timeout)
+{
+	struct rt6_info *rt, **back;
+	int more = 0;
+	unsigned long now = jiffies;
+
+	back = &fn->leaf;
+
+	for (rt = fn->leaf; rt;) {
+		if ((rt->rt6i_flags & RTF_CACHE) && rt->rt6i_use == 0) {
+			if (now - rt->rt6i_tstamp > timeout) {
+				struct rt6_info *old;
+
+				old = rt;
+
+				rt = rt->u.next;
+
+				*back = rt;
+
+				old->rt6i_node = NULL;
+				rt6_release(old);
+				rt6_stats.fib_rt_entries--;
+				continue;
+			}
+			more++;
+		}
+
+		/*
+		 *	check addrconf expiration here.
+		 */
+		back = &rt->u.next;
+		rt = rt->u.next;
+	}
+
+	return more;
+}
+
+struct fib6_gc_args {
+	unsigned long	timeout;
+	int		more;
+};
+
+static void fib6_garbage_collect(struct fib6_node *fn, void *p_arg)
+{
+	struct fib6_gc_args * args = (struct fib6_gc_args *) p_arg;
+
+	if (fn->fn_flags & RTN_RTINFO) {
+		int more;
+
+		more = fib6_gc_node(fn, args->timeout);
+
+		if (fn->leaf) {
+			args->more += more;
+			return;
+		}
+
+		rt6_stats.fib_route_nodes--;
+		fn->fn_flags &= ~RTN_RTINFO;
+	}
+
+	/*
+	 *	tree nodes (with no routing information)
+	 */
+
+	if (!fn->subtree && !(fn->fn_flags & RTN_TL_ROOT)) {
+		int children = 0;
+		struct fib6_node *chld = NULL;
+
+		if (fn->left) {
+			children++;
+			chld = fn->left;
+		}
+			
+		if (fn->right) {
+			children++;
+			chld = fn->right;
+		}
+		
+		if ((fn->fn_flags & RTN_ROOT)) {
+			if (children == 0) {
+				struct fib6_node *pn;
+
+				pn = fn->parent;
+				pn->subtree = NULL;
+
+				node_free(fn);
+			}
+			return;
+		}
+
+		if (children <= 1) {
+			struct fib6_node *pn = fn->parent;
+			
+			if (pn->left == fn)
+				pn->left = chld;
+			else
+				pn->right = chld;
+			
+			if (chld)
+				chld->parent = pn;
+			
+			if (fn->leaf)
+				rt6_release(fn->leaf);
+
+			node_free(fn);
+
+			return;
+		}
+	}
+
+	if (fn->leaf == NULL) {
+		struct rt6_info *nrt;
+		
+		nrt = fib6_find_prefix(fn);
+
+		if (nrt == NULL)
+			panic("fib6: inconsistent tree\n");
+
+		atomic_inc(&nrt->rt6i_ref);
+		fn->leaf = nrt;
+	}
+}
+
+static void fib6_run_gc(unsigned long dummy)
+{
+	struct fib6_gc_args arg = {
+		ipv6_config.rt_cache_timeout,
+		0
+	};
+
+	fib6_walk_tree(&ip6_routing_table, fib6_garbage_collect, &arg, 0);
+
+	if (arg.more) {
+		ip6_fib_timer.expires = jiffies + ipv6_config.rt_gc_period;
+		add_timer(&ip6_fib_timer);
+	} else {
+		ip6_fib_timer.expires = 0;
+	}
+}