X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fgraph.c;h=9d9bc1f301645690ea3968245c96e1e133bf3c00;hp=aa1ec72a26bddf757e3d0b4c21e1b45397e78ece;hb=116ba3b3da73fb857cf75b5c92c6aacd70d94dd9;hpb=c0a3f67a5d66088aaf526f1461986f9e86d5dd1f diff --git a/src/graph.c b/src/graph.c index aa1ec72a..9d9bc1f3 100644 --- a/src/graph.c +++ b/src/graph.c @@ -1,7 +1,7 @@ /* graph.c -- graph algorithms - Copyright (C) 2001 Guus Sliepen , - 2001 Ivo Timmermans + Copyright (C) 2001-2002 Guus Sliepen , + 2001-2002 Ivo Timmermans 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 @@ -17,7 +17,7 @@ along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - $Id: graph.c,v 1.1.2.5 2001/10/31 12:50:24 guus Exp $ + $Id: graph.c,v 1.1.2.12 2002/06/08 12:57:09 guus Exp $ */ /* We need to generate two trees from the graph: @@ -38,17 +38,31 @@ For the SSSP algorithm Dijkstra's seems to be a nice choice. Currently a simple breadth-first search is presented here. + + The SSSP algorithm will also be used to determine whether nodes are directly, + indirectly or not reachable from the source. It will also set the correct + destination address and port of a node if possible. */ +#include "config.h" + +#include #include #include "config.h" #include +#ifdef HAVE_SYS_PARAM_H + #include +#endif +#include #include +#include +#include "netutl.h" #include "node.h" #include "edge.h" #include "connection.h" +#include "process.h" #include "system.h" @@ -67,6 +81,22 @@ void mst_kruskal(void) int safe_edges = 0; int skipped; + /* Clear MST status on connections */ + + for(node = connection_tree->head; node; node = node->next) + { + c = (connection_t *)node->data; + c->status.mst = 0; + } + + /* Do we have something to do at all? */ + + if(!edge_weight_tree->head) + return; + + if(debug_lvl >= DEBUG_SCARY_THINGS) + syslog(LOG_DEBUG, "Running Kruskal's algorithm:"); + /* Clear visited status on nodes */ for(node = node_tree->head; node; node = node->next) @@ -78,15 +108,7 @@ void mst_kruskal(void) /* Starting point */ - ((edge_t *)edge_weight_tree->head->data)->from->status.visited = 1; - - /* Clear MST status on connections */ - - for(node = connection_tree->head; node; node = node->next) - { - c = (connection_t *)node->data; - c->status.mst = 0; - } + ((edge_t *)edge_weight_tree->head->data)->from.node->status.visited = 1; /* Add safe edges */ @@ -95,37 +117,46 @@ void mst_kruskal(void) next = node->next; e = (edge_t *)node->data; - if(e->from->status.visited == e->to->status.visited) + if(e->from.node->status.visited == e->to.node->status.visited) { skipped = 1; continue; } - e->from->status.visited = 1; - e->to->status.visited = 1; + e->from.node->status.visited = 1; + e->to.node->status.visited = 1; if(e->connection) e->connection->status.mst = 1; safe_edges++; + if(debug_lvl >= DEBUG_SCARY_THINGS) + syslog(LOG_DEBUG, " Adding edge %s - %s weight %d", e->from.node->name, e->to.node->name, e->weight); + if(skipped) { next = edge_weight_tree->head; continue; } } + + if(debug_lvl >= DEBUG_SCARY_THINGS) + syslog(LOG_DEBUG, "Done, counted %d nodes and %d safe edges.", nodes, safe_edges); } /* Implementation of a simple breadth-first search algorithm. Running time: O(E) */ -void sssp_bfs(int prune) +void sssp_bfs(void) { avl_node_t *node, *from, *next, *to; edge_t *e; - node_t *n, *check; + node_t *n; + halfconnection_t to_hc, from_hc; avl_tree_t *todo_tree; + int indirect; + char *name; todo_tree = avl_alloc_tree(NULL, NULL); @@ -135,11 +166,13 @@ void sssp_bfs(int prune) { n = (node_t *)node->data; n->status.visited = 0; + n->status.indirect = 1; } /* Begin with myself */ myself->status.visited = 1; + myself->status.indirect = 0; myself->nexthop = myself; myself->via = myself; node = avl_alloc_node(); @@ -150,46 +183,108 @@ void sssp_bfs(int prune) while(todo_tree->head) { - for(from = todo_tree->head; from; from = next) + for(from = todo_tree->head; from; from = next) /* "from" is the node from which we start */ { next = from->next; n = (node_t *)from->data; - for(to = n->edge_tree->head; to; to = to->next) + for(to = n->edge_tree->head; to; to = to->next) /* "to" is the edge connected to "from" */ { e = (edge_t *)to->data; - if(e->from == n) - check = e->to; + if(e->from.node == n) /* "from_hc" is the halfconnection with .node == from */ + to_hc = e->to, from_hc = e->from; else - check = e->from; - - if(!check->status.visited) - { - check->status.visited = 1; - check->nexthop = (n->nexthop == myself) ? check : n->nexthop; - check->via = (e->options & OPTION_INDIRECT || n->via != n) ? n->via : check; - node = avl_alloc_node(); - node->data = check; - avl_insert_before(todo_tree, from, node); - } + to_hc = e->from, from_hc = e->to; + + /* 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); } } avl_free_tree(todo_tree); - /* Nodes we haven't visited are unreachable, prune them. */ + /* Check reachability status. */ - if(prune) - for(node = node_tree->head; node; node = next) - { - next = node->next; - n = (node_t *)node->data; + for(node = node_tree->head; node; node = next) + { + next = node->next; + n = (node_t *)node->data; - if(n->status.visited == 0) - node_del(n); + if(n->status.visited) + { + if(!n->status.reachable) + { + if(debug_lvl >= DEBUG_TRAFFIC) + syslog(LOG_DEBUG, _("Node %s (%s) became reachable"), n->name, n->hostname); + n->status.reachable = 1; + asprintf(&name, "hosts/%s-up", n->name); + execute_script(name); + free(name); + } + } + else + { + if(n->status.reachable) + { + if(debug_lvl >= DEBUG_TRAFFIC) + syslog(LOG_DEBUG, _("Node %s (%s) became unreachable"), n->name, n->hostname); + n->status.reachable = 0; + n->status.validkey = 0; + n->status.waitingforkey = 0; + n->sent_seqno = 0; + asprintf(&name, "hosts/%s-down", n->name); + execute_script(name); + free(name); + } } + } +} + +void graph(void) +{ + mst_kruskal(); + sssp_bfs(); }