Updated SSSP algorithm to automatically detect indirect links (if a node uses

different addresses for connections to other nodes).

diff --git a/src/graph.c b/src/graph.c
index dd080c0..29e25db 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 

-    $Id: graph.c,v 1.1.2.9 2002/03/12 16:30:15 guus Exp $
+    $Id: graph.c,v 1.1.2.10 2002/03/19 22:48:25 guus Exp $

 */
 
 /* We need to generate two trees from the graph:
 */
 
 /* We need to generate two trees from the graph:


@@ -151,6 +151,7 @@ void sssp_bfs(void)
   node_t *n;
   halfconnection_t to_hc, from_hc;
   avl_tree_t *todo_tree;
   node_t *n;
   halfconnection_t to_hc, from_hc;
   avl_tree_t *todo_tree;

+  int indirect;

 
   todo_tree = avl_alloc_tree(NULL, NULL);
 
 
   todo_tree = avl_alloc_tree(NULL, NULL);
 


@@ -160,11 +161,13 @@ void sssp_bfs(void)
     {
       n = (node_t *)node->data;
       n->status.visited = 0;
     {
       n = (node_t *)node->data;
       n->status.visited = 0;

+      n->status.indirect = 1;

     }
 
   /* Begin with myself */
 
   myself->status.visited = 1;
     }
 
   /* Begin with myself */
 
   myself->status.visited = 1;

+  myself->status.indirect = 0;

   myself->nexthop = myself;
   myself->via = myself;
   node = avl_alloc_node();
   myself->nexthop = myself;
   myself->via = myself;
   node = avl_alloc_node();


@@ -189,25 +192,47 @@ void sssp_bfs(void)
               else
                 to_hc = e->from, from_hc = e->to;
 
               else
                 to_hc = e->from, from_hc = e->to;
 

-              if(!to_hc.node->status.visited)
-                {
-                  to_hc.node->status.visited = 1;
-                  to_hc.node->nexthop = (n->nexthop == myself) ? to_hc.node : n->nexthop;
-                  to_hc.node->via = (e->options & OPTION_INDIRECT || n->via != n) ? n->via : to_hc.node;
-                 to_hc.node->options = e->options;
-                  if(sockaddrcmp(&to_hc.node->address, &to_hc.udpaddress))
-                 {
-                    node = avl_unlink(node_udp_tree, to_hc.node);
-                    to_hc.node->address = to_hc.udpaddress;
-                   if(to_hc.node->hostname)
-                     free(to_hc.node->hostname);
-                   to_hc.node->hostname = sockaddr2hostname(&to_hc.udpaddress);
-                    avl_insert_node(node_udp_tree, node);
-                 }
-                  node = avl_alloc_node();
-                  node->data = to_hc.node;
-                  avl_insert_before(todo_tree, from, node);
-                }
+              /* Situation:
+
+                         /
+                        /
+                ------(n)from_hc-----to_hc
+                        \
+                         \
+
+                 n->address is set to the to_hc.udpaddress of the edge left of n.
+                We are currently examining the edge right of n:
+
+                 - If from_hc.udpaddress != n->address, then to_hc.node is probably
+                  not reachable for the nodes left of n. We do as if the indirectdata
+                  flag is set on edge e.
+                - If edge e provides for better reachability of to_hc.node, update
+                  to_hc.node and (re)add it to the todo_tree to (re)examine the reachability
+                  of nodes behind it.
+             */
+
+              indirect = n->status.indirect || e->options & OPTION_INDIRECT || ((n != myself) && sockaddrcmp(&n->address, &from_hc.udpaddress));
+
+              if(to_hc.node->status.visited && (!to_hc.node->status.indirect || indirect))
+               continue;
+
+              to_hc.node->status.visited = 1;
+              to_hc.node->status.indirect = indirect;
+              to_hc.node->nexthop = (n->nexthop == myself) ? to_hc.node : n->nexthop;
+              to_hc.node->via = indirect ? n->via : to_hc.node;
+             to_hc.node->options = e->options;
+              if(sockaddrcmp(&to_hc.node->address, &to_hc.udpaddress))
+             {
+                node = avl_unlink(node_udp_tree, to_hc.node);
+                to_hc.node->address = to_hc.udpaddress;
+               if(to_hc.node->hostname)
+                 free(to_hc.node->hostname);
+               to_hc.node->hostname = sockaddr2hostname(&to_hc.udpaddress);
+                avl_insert_node(node_udp_tree, node);
+             }
+              node = avl_alloc_node();
+              node->data = to_hc.node;
+              avl_insert_before(todo_tree, from, node);

             }
 
           avl_delete_node(todo_tree, from);
             }
 
           avl_delete_node(todo_tree, from);

diff --git a/src/node.h b/src/node.h
index 6493852..98147d3 100644 (file)
--- a/src/node.h
+++ b/src/node.h
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 

-    $Id: node.h,v 1.1.2.12 2002/02/18 16:25:16 guus Exp $
+    $Id: node.h,v 1.1.2.13 2002/03/19 22:48:25 guus Exp $

 */
 
 #ifndef __TINC_NODE_H__
 */
 
 #ifndef __TINC_NODE_H__


@@ -34,7 +34,8 @@ typedef struct node_status_t {
   int waitingforkey:1;             /* 1 if we already sent out a request */
   int visited:1;                   /* 1 if this node has been visited by one of the graph algorithms */
   int reachable:1;                 /* 1 if this node is reachable in the graph */
   int waitingforkey:1;             /* 1 if we already sent out a request */
   int visited:1;                   /* 1 if this node has been visited by one of the graph algorithms */
   int reachable:1;                 /* 1 if this node is reachable in the graph */

-  int unused:27;
+  int indirect:1;                  /* 1 if this node is not directly reachable by us */
+  int unused:26;

 } node_status_t;
 
 typedef struct node_t {
 } node_status_t;
 
 typedef struct node_t {