From 718e3744195351130f4ce7dbe0613f4b3e23df93 Mon Sep 17 00:00:00 2001
From: paul <paul>
Date: Fri, 13 Dec 2002 20:15:29 +0000
Subject: Initial revision

---
 bgpd/bgp_table.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 489 insertions(+)
 create mode 100644 bgpd/bgp_table.c

(limited to 'bgpd/bgp_table.c')

diff --git a/bgpd/bgp_table.c b/bgpd/bgp_table.c
new file mode 100644
index 00000000..a2a3c97b
--- /dev/null
+++ b/bgpd/bgp_table.c
@@ -0,0 +1,489 @@
+/* BGP routing table
+   Copyright (C) 1998, 2001 Kunihiro Ishiguro
+
+This file is part of GNU Zebra.
+
+GNU Zebra 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, or (at your option) any
+later version.
+
+GNU Zebra is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Zebra; see the file COPYING.  If not, write to the Free
+Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.  */
+
+#include <zebra.h>
+
+#include "prefix.h"
+#include "memory.h"
+#include "sockunion.h"
+#include "vty.h"
+
+#include "bgpd/bgpd.h"
+#include "bgpd/bgp_table.h"
+
+void bgp_node_delete (struct bgp_node *);
+void bgp_table_free (struct bgp_table *);
+
+struct bgp_table *
+bgp_table_init (void)
+{
+  struct bgp_table *rt;
+
+  rt = XMALLOC (MTYPE_BGP_TABLE, sizeof (struct bgp_table));
+  memset (rt, 0, sizeof (struct bgp_table));
+  return rt;
+}
+
+void
+bgp_table_finish (struct bgp_table *rt)
+{
+  bgp_table_free (rt);
+}
+
+struct bgp_node *
+bgp_node_create ()
+{
+  struct bgp_node *rn;
+
+  rn = (struct bgp_node *) XMALLOC (MTYPE_BGP_NODE, sizeof (struct bgp_node));
+  memset (rn, 0, sizeof (struct bgp_node));
+  return rn;
+}
+
+/* Allocate new route node with prefix set. */
+struct bgp_node *
+bgp_node_set (struct bgp_table *table, struct prefix *prefix)
+{
+  struct bgp_node *node;
+  
+  node = bgp_node_create ();
+
+  prefix_copy (&node->p, prefix);
+  node->table = table;
+
+  return node;
+}
+
+/* Free route node. */
+void
+bgp_node_free (struct bgp_node *node)
+{
+  XFREE (MTYPE_BGP_NODE, node);
+}
+
+/* Free route table. */
+void
+bgp_table_free (struct bgp_table *rt)
+{
+  struct bgp_node *tmp_node;
+  struct bgp_node *node;
+ 
+  if (rt == NULL)
+    return;
+
+  node = rt->top;
+
+  while (node)
+    {
+      if (node->l_left)
+	{
+	  node = node->l_left;
+	  continue;
+	}
+
+      if (node->l_right)
+	{
+	  node = node->l_right;
+	  continue;
+	}
+
+      tmp_node = node;
+      node = node->parent;
+
+      if (node != NULL)
+	{
+	  if (node->l_left == tmp_node)
+	    node->l_left = NULL;
+	  else
+	    node->l_right = NULL;
+
+	  bgp_node_free (tmp_node);
+	}
+      else
+	{
+	  bgp_node_free (tmp_node);
+	  break;
+	}
+    }
+ 
+  XFREE (MTYPE_BGP_TABLE, rt);
+  return;
+}
+
+/* Utility mask array. */
+static u_char maskbit[] = 
+{
+  0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
+};
+
+/* Common prefix route genaration. */
+static void
+route_common (struct prefix *n, struct prefix *p, struct prefix *new)
+{
+  int i;
+  u_char diff;
+  u_char mask;
+
+  u_char *np = (u_char *)&n->u.prefix;
+  u_char *pp = (u_char *)&p->u.prefix;
+  u_char *newp = (u_char *)&new->u.prefix;
+
+  for (i = 0; i < p->prefixlen / 8; i++)
+    {
+      if (np[i] == pp[i])
+	newp[i] = np[i];
+      else
+	break;
+    }
+
+  new->prefixlen = i * 8;
+
+  if (new->prefixlen != p->prefixlen)
+    {
+      diff = np[i] ^ pp[i];
+      mask = 0x80;
+      while (new->prefixlen < p->prefixlen && !(mask & diff))
+	{
+	  mask >>= 1;
+	  new->prefixlen++;
+	}
+      newp[i] = np[i] & maskbit[new->prefixlen % 8];
+    }
+}
+
+/* Macro version of check_bit (). */
+#define CHECK_BIT(X,P) ((((u_char *)(X))[(P) / 8]) >> (7 - ((P) % 8)) & 1)
+
+/* Check bit of the prefix. */
+static int
+check_bit (u_char *prefix, u_char prefixlen)
+{
+  int offset;
+  int shift;
+  u_char *p = (u_char *)prefix;
+
+  assert (prefixlen <= 128);
+
+  offset = prefixlen / 8;
+  shift = 7 - (prefixlen % 8);
+  
+  return (p[offset] >> shift & 1);
+}
+
+/* Macro version of set_link (). */
+#define SET_LINK(X,Y) (X)->link[CHECK_BIT(&(Y)->prefix,(X)->prefixlen)] = (Y);\
+                      (Y)->parent = (X)
+
+static void
+set_link (struct bgp_node *node, struct bgp_node *new)
+{
+  int bit;
+    
+  bit = check_bit (&new->p.u.prefix, node->p.prefixlen);
+
+  assert (bit == 0 || bit == 1);
+
+  node->link[bit] = new;
+  new->parent = node;
+}
+
+/* Lock node. */
+struct bgp_node *
+bgp_lock_node (struct bgp_node *node)
+{
+  node->lock++;
+  return node;
+}
+
+/* Unlock node. */
+void
+bgp_unlock_node (struct bgp_node *node)
+{
+  node->lock--;
+
+  if (node->lock == 0)
+    bgp_node_delete (node);
+}
+
+/* Find matched prefix. */
+struct bgp_node *
+bgp_node_match (struct bgp_table *table, struct prefix *p)
+{
+  struct bgp_node *node;
+  struct bgp_node *matched;
+
+  matched = NULL;
+  node = table->top;
+
+  /* Walk down tree.  If there is matched route then store it to
+     matched. */
+  while (node && node->p.prefixlen <= p->prefixlen && 
+	 prefix_match (&node->p, p))
+    {
+      if (node->info)
+	matched = node;
+      node = node->link[check_bit(&p->u.prefix, node->p.prefixlen)];
+    }
+
+  /* If matched route found, return it. */
+  if (matched)
+    return bgp_lock_node (matched);
+
+  return NULL;
+}
+
+struct bgp_node *
+bgp_node_match_ipv4 (struct bgp_table *table, struct in_addr *addr)
+{
+  struct prefix_ipv4 p;
+
+  memset (&p, 0, sizeof (struct prefix_ipv4));
+  p.family = AF_INET;
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+  p.prefix = *addr;
+
+  return bgp_node_match (table, (struct prefix *) &p);
+}
+
+#ifdef HAVE_IPV6
+struct bgp_node *
+bgp_node_match_ipv6 (struct bgp_table *table, struct in6_addr *addr)
+{
+  struct prefix_ipv6 p;
+
+  memset (&p, 0, sizeof (struct prefix_ipv6));
+  p.family = AF_INET6;
+  p.prefixlen = IPV6_MAX_PREFIXLEN;
+  p.prefix = *addr;
+
+  return bgp_node_match (table, (struct prefix *) &p);
+}
+#endif /* HAVE_IPV6 */
+
+/* Lookup same prefix node.  Return NULL when we can't find route. */
+struct bgp_node *
+bgp_node_lookup (struct bgp_table *table, struct prefix *p)
+{
+  struct bgp_node *node;
+
+  node = table->top;
+
+  while (node && node->p.prefixlen <= p->prefixlen && 
+	 prefix_match (&node->p, p))
+    {
+      if (node->p.prefixlen == p->prefixlen && node->info)
+	return bgp_lock_node (node);
+
+      node = node->link[check_bit(&p->u.prefix, node->p.prefixlen)];
+    }
+
+  return NULL;
+}
+
+/* Add node to routing table. */
+struct bgp_node *
+bgp_node_get (struct bgp_table *table, struct prefix *p)
+{
+  struct bgp_node *new;
+  struct bgp_node *node;
+  struct bgp_node *match;
+
+  match = NULL;
+  node = table->top;
+  while (node && node->p.prefixlen <= p->prefixlen && 
+	 prefix_match (&node->p, p))
+    {
+      if (node->p.prefixlen == p->prefixlen)
+	{
+	  bgp_lock_node (node);
+	  return node;
+	}
+      match = node;
+      node = node->link[check_bit(&p->u.prefix, node->p.prefixlen)];
+    }
+
+  if (node == NULL)
+    {
+      new = bgp_node_set (table, p);
+      if (match)
+	set_link (match, new);
+      else
+	table->top = new;
+    }
+  else
+    {
+      new = bgp_node_create ();
+      route_common (&node->p, p, &new->p);
+      new->p.family = p->family;
+      new->table = table;
+      set_link (new, node);
+
+      if (match)
+	set_link (match, new);
+      else
+	table->top = new;
+
+      if (new->p.prefixlen != p->prefixlen)
+	{
+	  match = new;
+	  new = bgp_node_set (table, p);
+	  set_link (match, new);
+	}
+    }
+  bgp_lock_node (new);
+  
+  return new;
+}
+
+/* Delete node from the routing table. */
+void
+bgp_node_delete (struct bgp_node *node)
+{
+  struct bgp_node *child;
+  struct bgp_node *parent;
+
+  assert (node->lock == 0);
+  assert (node->info == NULL);
+
+  if (node->l_left && node->l_right)
+    return;
+
+  if (node->l_left)
+    child = node->l_left;
+  else
+    child = node->l_right;
+
+  parent = node->parent;
+
+  if (child)
+    child->parent = parent;
+
+  if (parent)
+    {
+      if (parent->l_left == node)
+	parent->l_left = child;
+      else
+	parent->l_right = child;
+    }
+  else
+    node->table->top = child;
+
+  bgp_node_free (node);
+
+  /* If parent node is stub then delete it also. */
+  if (parent && parent->lock == 0)
+    bgp_node_delete (parent);
+}
+
+/* Get fist node and lock it.  This function is useful when one want
+   to lookup all the node exist in the routing table. */
+struct bgp_node *
+bgp_table_top (struct bgp_table *table)
+{
+  /* If there is no node in the routing table return NULL. */
+  if (table->top == NULL)
+    return NULL;
+
+  /* Lock the top node and return it. */
+  bgp_lock_node (table->top);
+  return table->top;
+}
+
+/* Unlock current node and lock next node then return it. */
+struct bgp_node *
+bgp_route_next (struct bgp_node *node)
+{
+  struct bgp_node *next;
+  struct bgp_node *start;
+
+  /* Node may be deleted from bgp_unlock_node so we have to preserve
+     next node's pointer. */
+
+  if (node->l_left)
+    {
+      next = node->l_left;
+      bgp_lock_node (next);
+      bgp_unlock_node (node);
+      return next;
+    }
+  if (node->l_right)
+    {
+      next = node->l_right;
+      bgp_lock_node (next);
+      bgp_unlock_node (node);
+      return next;
+    }
+
+  start = node;
+  while (node->parent)
+    {
+      if (node->parent->l_left == node && node->parent->l_right)
+	{
+	  next = node->parent->l_right;
+	  bgp_lock_node (next);
+	  bgp_unlock_node (start);
+	  return next;
+	}
+      node = node->parent;
+    }
+  bgp_unlock_node (start);
+  return NULL;
+}
+
+/* Unlock current node and lock next node until limit. */
+struct bgp_node *
+bgp_route_next_until (struct bgp_node *node, struct bgp_node *limit)
+{
+  struct bgp_node *next;
+  struct bgp_node *start;
+
+  /* Node may be deleted from bgp_unlock_node so we have to preserve
+     next node's pointer. */
+
+  if (node->l_left)
+    {
+      next = node->l_left;
+      bgp_lock_node (next);
+      bgp_unlock_node (node);
+      return next;
+    }
+  if (node->l_right)
+    {
+      next = node->l_right;
+      bgp_lock_node (next);
+      bgp_unlock_node (node);
+      return next;
+    }
+
+  start = node;
+  while (node->parent && node != limit)
+    {
+      if (node->parent->l_left == node && node->parent->l_right)
+	{
+	  next = node->parent->l_right;
+	  bgp_lock_node (next);
+	  bgp_unlock_node (start);
+	  return next;
+	}
+      node = node->parent;
+    }
+  bgp_unlock_node (start);
+  return NULL;
+}
-- 
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