/* This file is part of GNUnet. (C) 2001 - 2011 Christian Grothoff (and other contributing authors) GNUnet 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 3, or (at your option) any later version. GNUnet 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 GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file mesh/mesh_tunnel_tree.c * @brief Tunnel tree handling functions * @author Bartlomiej Polot */ #include "mesh.h" #include "mesh_tunnel_tree.h" #define MESH_TREE_DEBUG GNUNET_YES /** * Create a new path * * @param lenght How many hops will the path have. * * @return A newly allocated path with a peer array of the specified length. */ struct MeshPeerPath * path_new (unsigned int length) { struct MeshPeerPath *p; p = GNUNET_malloc (sizeof(struct MeshPeerPath)); if (length > 0) { p->length = length; p->peers = GNUNET_malloc (length * sizeof(GNUNET_PEER_Id)); } return p; } /** * Invert the path * * @param p the path to invert */ void path_invert (struct MeshPeerPath *path) { GNUNET_PEER_Id aux; unsigned int i; for (i = 0; i < path->length / 2; i++) { aux = path->peers[i]; path->peers[i] = path->peers[path->length - i - 1]; path->peers[path->length - i - 1] = aux; } } /** * Duplicate a path, incrementing short peer's rc. * * @param p The path to duplicate. */ struct MeshPeerPath * path_duplicate (struct MeshPeerPath *path) { struct MeshPeerPath *aux; unsigned int i; aux = path_new(path->length); memcpy (aux->peers, path->peers, path->length * sizeof(GNUNET_PEER_Id)); for (i = 0; i < path->length; i++) GNUNET_PEER_change_rc(path->peers[i], 1); return aux; } /** * Find the first peer whom to send a packet to go down this path * * @param t The tunnel tree to use * @param peer The peerinfo of the peer we are trying to reach * * @return peerinfo of the peer who is the first hop in the tunnel * NULL on error */ struct GNUNET_PeerIdentity * path_get_first_hop (struct MeshTunnelTree *t, GNUNET_PEER_Id peer) { struct GNUNET_PeerIdentity id; struct GNUNET_PeerIdentity *r; GNUNET_PEER_resolve (peer, &id); r = GNUNET_CONTAINER_multihashmap_get (t->first_hops, &id.hashPubKey); GNUNET_break (NULL != r); return r; } /** * Get the length of a path * * @param path The path to measure, with the local peer at any point of it * * @return Number of hops to reach destination * UINT_MAX in case the peer is not in the path */ unsigned int path_get_length (struct MeshPeerPath *path) { if (NULL == path) return UINT_MAX; return path->length; } /** * Get the cost of the path relative to the already built tunnel tree * * @param t The tunnel tree to which compare * @param path The individual path to reach a peer * * @return Number of hops to reach destination, UINT_MAX in case the peer is not * in the path * * TODO: remove dummy implementation, look into the tunnel tree */ unsigned int path_get_cost (struct MeshTunnelTree *t, struct MeshPeerPath *path) { return path_get_length (path); } /** * Destroy the path and free any allocated resources linked to it * * @param p the path to destroy * * @return GNUNET_OK on success */ int path_destroy (struct MeshPeerPath *p) { GNUNET_PEER_decrement_rcs (p->peers, p->length); GNUNET_free (p->peers); GNUNET_free (p); return GNUNET_OK; } /** * Allocates and initializes a new node. * Sets ID and parent of the new node and inserts it in the DLL of the parent * * @param parent Node that will be the parent from the new node, NULL for root * @param peer Short Id of the new node * * @return Newly allocated node */ static struct MeshTunnelTreeNode * tree_node_new(struct MeshTunnelTreeNode *parent, GNUNET_PEER_Id peer) { struct MeshTunnelTreeNode *node; node = GNUNET_malloc(sizeof(struct MeshTunnelTreeNode)); node->peer = peer; GNUNET_PEER_change_rc(peer, 1); node->parent = parent; if (NULL != parent) GNUNET_CONTAINER_DLL_insert(parent->children_head, parent->children_tail, node); return node; } static void tree_node_debug(struct MeshTunnelTreeNode *n, uint16_t level) { struct MeshTunnelTreeNode *c; uint16_t i; for (i = 0; i < level; i++) fprintf(stderr, " "); if (n->status == MESH_PEER_READY) fprintf(stderr, "#"); if (n->status == MESH_PEER_SEARCHING) fprintf(stderr, "+"); if (n->status == MESH_PEER_RELAY) fprintf(stderr, "-"); if (n->status == MESH_PEER_RECONNECTING) fprintf(stderr, "*"); fprintf(stderr, "%u [%p] ", n->peer, n); if (NULL != n->parent) fprintf(stderr, "(-> %u)\n", n->parent->peer); else fprintf(stderr, "(root)\n"); for (c = n->children_head; NULL != c; c = c->next) tree_node_debug(c, level + 1); } /** * Destroys and frees the node and all children * * @param n Parent node to be destroyed */ static void tree_node_destroy (struct MeshTunnelTreeNode *parent) { struct MeshTunnelTreeNode *n; struct MeshTunnelTreeNode *next; n = parent->children_head; while (NULL != n) { next = n->next; tree_node_destroy(n); n = next; } GNUNET_PEER_change_rc(parent->peer, -1); if (NULL != parent->parent) GNUNET_CONTAINER_DLL_remove(parent->parent->children_head, parent->parent->children_tail, parent); GNUNET_free(parent); } /** * Create a new tunnel tree associated to a tunnel * * @param t Tunnel this tree will represent * @param peer A short peer id of the root of the tree * * @return A newly allocated and initialized tunnel tree */ struct MeshTunnelTree * tree_new (struct MeshTunnel *t, GNUNET_PEER_Id peer) { struct MeshTunnelTree *tree; tree = GNUNET_malloc(sizeof (struct MeshTunnelTree)); tree->first_hops = GNUNET_CONTAINER_multihashmap_create(32); tree->root = tree_node_new(NULL, peer); tree->root->status = MESH_PEER_ROOT; tree->t = t; tree->root->t = t; return tree; } /** * Recursively find the given peer in the tree. * * @param t Tunnel where to look for the peer. * @param peer Peer to find * * @return Pointer to the node of the peer. NULL if not found. */ struct MeshTunnelTreeNode * tree_find_peer (struct MeshTunnelTreeNode *parent, GNUNET_PEER_Id peer_id) { struct MeshTunnelTreeNode *n; struct MeshTunnelTreeNode *r; if (parent->peer == peer_id) return parent; for (n = parent->children_head; NULL != n; n = n->next) { r = tree_find_peer (n, peer_id); if (NULL != r) return r; } return NULL; } /** * Recusively mark peer and children as disconnected, notify client * * @param tree Tree this node belongs to * @param parent Node to be clean, potentially with children * @param cb Callback to use to notify about disconnected peers. */ static void tree_mark_peers_disconnected (struct MeshTunnelTree *tree, struct MeshTunnelTreeNode *parent, MeshNodeDisconnectCB cb) { struct GNUNET_PeerIdentity *pi; struct GNUNET_PeerIdentity id; struct MeshTunnelTreeNode *n; for (n = parent->children_head; NULL != n; n = n->next) { tree_mark_peers_disconnected (tree, n, cb); } if (MESH_PEER_READY == parent->status && NULL != cb) { cb (parent); } parent->status = MESH_PEER_RECONNECTING; /* Remove and free info about first hop */ GNUNET_PEER_resolve(parent->peer, &id); pi = GNUNET_CONTAINER_multihashmap_get(tree->first_hops, &id.hashPubKey); GNUNET_CONTAINER_multihashmap_remove_all(tree->first_hops, &id.hashPubKey); if (NULL != pi) GNUNET_free(pi); } /** * Recusively update the info about what is the first hop to reach the node * * @param tree Tree this nodes belongs to * @param parent Node to be start updating * @param hop If known, ID of the first hop. * If not known, NULL to find out and pass on children. */ void tree_update_first_hops (struct MeshTunnelTree *tree, struct MeshTunnelTreeNode *parent, struct GNUNET_PeerIdentity *hop) { struct GNUNET_PeerIdentity pi; struct GNUNET_PeerIdentity *copy; struct GNUNET_PeerIdentity id; struct MeshTunnelTreeNode *n; #if MESH_TREE_DEBUG GNUNET_PEER_resolve(parent->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Finding first hop for %s.\n", GNUNET_i2s (&id)); #endif if (NULL == hop) { struct MeshTunnelTreeNode *aux; struct MeshTunnelTreeNode *old; aux = old = parent; while (aux != tree->me) { #if MESH_TREE_DEBUG GNUNET_PEER_resolve(old->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: ... its not %s.\n", GNUNET_i2s (&id)); #endif old = aux; aux = aux->parent; GNUNET_assert(NULL != aux); } #if MESH_TREE_DEBUG GNUNET_PEER_resolve(old->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: It's %s!\n", GNUNET_i2s (&id)); #endif hop = π GNUNET_PEER_resolve(old->peer, hop); } copy = GNUNET_malloc(sizeof(struct GNUNET_PeerIdentity)); *copy = *hop; GNUNET_PEER_resolve(parent->peer, &id); GNUNET_CONTAINER_multihashmap_put( tree->first_hops, &id.hashPubKey, copy, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST); for (n = parent->children_head; NULL != n; n = n->next) { tree_update_first_hops (tree, n, hop); } } /** * Delete the current path to the peer, including all now unused relays. * The destination peer is NOT destroyed, it is returned in order to either set * a new path to it or destroy it explicitly, taking care of it's child nodes. * * @param t Tunnel tree where to delete the path from. * @param peer Destination peer whose path we want to remove. * @param cb Callback to use to notify about disconnected peers. * * @return pointer to the pathless node. * NULL when not found */ struct MeshTunnelTreeNode * tree_del_path (struct MeshTunnelTree *t, GNUNET_PEER_Id peer_id, MeshNodeDisconnectCB cb) { struct MeshTunnelTreeNode *parent; struct MeshTunnelTreeNode *node; struct MeshTunnelTreeNode *n; #if MESH_TREE_DEBUG struct GNUNET_PeerIdentity id; GNUNET_PEER_resolve(peer_id, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Deleting path to %s.\n", GNUNET_i2s (&id)); #endif if (peer_id == t->root->peer) return NULL; for (n = t->disconnected_head; NULL != n; n = n->next) { if (n->peer == peer_id) { /* Was already pathless, waiting for reconnection */ GNUNET_CONTAINER_DLL_remove (t->disconnected_head, t->disconnected_tail, n); return n; } } n = tree_find_peer (t->root, peer_id); if (NULL == n) return NULL; node = n; parent = n->parent; GNUNET_CONTAINER_DLL_remove(parent->children_head, parent->children_tail, n); n->parent = NULL; while (MESH_PEER_RELAY == parent->status && NULL == parent->children_head) { #if MESH_TREE_DEBUG GNUNET_PEER_resolve(parent->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Deleting node %s.\n", GNUNET_i2s (&id)); #endif n = parent->parent; tree_node_destroy(parent); parent = n; } #if MESH_TREE_DEBUG GNUNET_PEER_resolve(parent->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Not deleted peer %s.\n", GNUNET_i2s (&id)); #endif tree_mark_peers_disconnected (t, node, cb); return node; } /** * Return a newly allocated individual path to reach a peer from the local peer, * according to the path tree of some tunnel. * * @param t Tunnel from which to read the path tree * @param peer_info Destination peer to whom we want a path * * @return A newly allocated individual path to reach the destination peer. * Path must be destroyed afterwards. */ struct MeshPeerPath * tree_get_path_to_peer(struct MeshTunnelTree *t, GNUNET_PEER_Id peer) { struct MeshTunnelTreeNode *n; struct MeshPeerPath *p; GNUNET_PEER_Id myid = t->me->peer; n = tree_find_peer(t->me, peer); p = path_new(0); /* Building the path (inverted!) */ while (n->peer != myid) { GNUNET_array_append(p->peers, p->length, n->peer); GNUNET_PEER_change_rc(n->peer, 1); n = n->parent; GNUNET_assert(NULL != n); } GNUNET_array_append(p->peers, p->length, myid); GNUNET_PEER_change_rc(myid, 1); path_invert(p); return p; } /** * Integrate a stand alone path into the tunnel tree. * If the peer toward which the new path is already in the tree, the peer * and its children will be maked as disconnected and the callback * will be called on each one of them. They will be maked as online only after * receiving a PATH ACK for the new path for each one of them, so the caller * should take care of sending a new CREATE PATH message for each disconnected * peer. * * @param t Tunnel where to add the new path. * @param p Path to be integrated. * @param cb Callback to use to notify about peers temporarily disconnecting * * @return GNUNET_OK in case of success. * GNUNET_SYSERR in case of error. * * TODO: optimize * - go backwards on path looking for each peer in the present tree * - do not disconnect peers until new path is created & connected */ int tree_add_path (struct MeshTunnelTree *t, const struct MeshPeerPath *p, MeshNodeDisconnectCB cb) { struct MeshTunnelTreeNode *parent; struct MeshTunnelTreeNode *oldnode; struct MeshTunnelTreeNode *n; struct MeshTunnelTreeNode *c; struct GNUNET_PeerIdentity id; GNUNET_PEER_Id myid; int me; // int oldnode_is_me; unsigned int i; #if MESH_TREE_DEBUG GNUNET_PEER_resolve(p->peers[p->length - 1], &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Adding path [%u] towards peer %s.\n", p->length, GNUNET_i2s (&id)); #endif if (NULL != t->me) myid = t->me->peer; else myid = 0; GNUNET_assert(0 != p->length); parent = n = t->root; if (n->peer != p->peers[0]) { GNUNET_break (0); return GNUNET_SYSERR; } if (1 == p->length) return GNUNET_OK; oldnode = tree_del_path (t, p->peers[p->length - 1], cb); /* Look for the first node that is not already present in the tree * * Assuming that the tree is somewhat balanced, O(log n * log N). * - Length of the path is expected to be log N (size of whole network). * - Each level of the tree is expected to have log n children (size of tree). */ me = t->root->peer == myid ? 0 : -1; for (i = 1; i < p->length; i++) { #if MESH_TREE_DEBUG GNUNET_PEER_resolve(p->peers[i], &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Looking for peer %s.\n", GNUNET_i2s (&id)); #endif parent = n; if (p->peers[i] == myid) me = i; for (c = n->children_head; NULL != c; c = c->next) { if (c->peer == p->peers[i]) { #if MESH_TREE_DEBUG GNUNET_PEER_resolve(parent->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Found in children of %s.\n", GNUNET_i2s (&id)); #endif n = c; break; } } /* If we couldn't find a child equal to path[i], we have reached the end * of the common path. */ if (parent == n) break; } #if MESH_TREE_DEBUG GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: All childen visited.\n"); #endif /* Add the rest of the path as a branch from parent. */ while (i < p->length) { #if MESH_TREE_DEBUG GNUNET_PEER_resolve(p->peers[i], &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Adding peer %s.\n", GNUNET_i2s (&id)); GNUNET_PEER_resolve(parent->peer, &id); GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: to %s.\n", GNUNET_i2s (&id)); #endif if (i == p->length - 1 && NULL != oldnode) { #if MESH_TREE_DEBUG GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Putting old node into place.\n"); #endif oldnode->parent = parent; GNUNET_CONTAINER_DLL_insert(parent->children_head, parent->children_tail, oldnode); tree_update_first_hops (t, oldnode, NULL); n = oldnode; } else { #if MESH_TREE_DEBUG GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: Creating new node.\n"); #endif n = tree_node_new(parent, p->peers[i]); n->t = t->t; n->status = MESH_PEER_RELAY; } i++; parent = n; } n->status = MESH_PEER_SEARCHING; /* Add info about first hop into hashmap. */ if (-1 != me && me < p->length - 1) { #if MESH_TREE_DEBUG GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "MESH: finding first hop (own pos %d/%u)\n", me, p->length - 1); #endif GNUNET_PEER_resolve (p->peers[me + 1], &id); tree_update_first_hops(t, tree_find_peer(t->root, p->peers[p->length - 1]), &id); } #if MESH_TREE_DEBUG GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "tree: New node added.\n"); #endif return GNUNET_OK; } /** * Notifies a tree that a connection it might be using is broken. * Marks all peers down the paths as disconnected and notifies the client. * * @param t Tree to use. * @param p1 Short id of one of the peers (order unimportant) * @param p2 Short id of one of the peers (order unimportant) * @param cb Function to call for every peer that is marked as disconnected. * * @return Short ID of the first disconnected peer in the tree. */ GNUNET_PEER_Id tree_notify_connection_broken (struct MeshTunnelTree *t, GNUNET_PEER_Id p1, GNUNET_PEER_Id p2, MeshNodeDisconnectCB cb) { struct MeshTunnelTreeNode *n; struct MeshTunnelTreeNode *c; n = tree_find_peer(t->me, p1); if (NULL == n) return 0; if (NULL != n->parent && n->parent->peer == p2) { tree_mark_peers_disconnected(t, n, cb); GNUNET_CONTAINER_DLL_remove(n->parent->children_head, n->parent->children_tail, n); GNUNET_CONTAINER_DLL_insert(t->disconnected_head, t->disconnected_tail, n); return p1; } for (c = n->children_head; NULL != c; c = c->next) { if (c->peer == p2) { tree_mark_peers_disconnected(t, c, cb); GNUNET_CONTAINER_DLL_remove(n->children_head, n->children_tail, c); GNUNET_CONTAINER_DLL_insert(t->disconnected_head, t->disconnected_tail, c); return p2; } } return 0; } /** * Deletes a peer from a tunnel, liberating all unused resources on the path to * it. It shouldn't have children, if it has they will be destroyed as well. * If the tree is not local and no longer has any paths, the root node will be * destroyed and marked as NULL. * * @param t Tunnel tree to use. * @param peer Short ID of the peer to remove from the tunnel tree. * @param cb Callback to notify client of disconnected peers. * * @return GNUNET_OK or GNUNET_SYSERR */ int tree_del_peer (struct MeshTunnelTree *t, GNUNET_PEER_Id peer, MeshNodeDisconnectCB cb) { struct MeshTunnelTreeNode *n; n = tree_del_path(t, peer, cb); if (NULL == n) return GNUNET_SYSERR; GNUNET_break_op (NULL == n->children_head); tree_node_destroy(n); if (NULL == t->root->children_head && t->me != t->root) { tree_node_destroy (t->root); t->root = NULL; } return GNUNET_OK; } /** * Print the tree on stderr * * @param t The tree */ void tree_debug(struct MeshTunnelTree *t) { tree_node_debug(t->root, 0); } /** * Iterator over hash map peer entries and frees all data in it. * Used prior to destroying a hashmap. Makes you miss anonymous functions in C. * * @param cls closure * @param key current key code (will no longer contain valid data!!) * @param value value in the hash map (treated as void *) * @return GNUNET_YES if we should continue to iterate, GNUNET_NO if not. */ static int iterate_free (void *cls, const GNUNET_HashCode * key, void *value) { GNUNET_free(value); return GNUNET_YES; } /** * Destroy the whole tree and free all used memory and Peer_Ids * * @param t Tree to be destroyed */ void tree_destroy (struct MeshTunnelTree *t) { tree_node_destroy(t->root); GNUNET_CONTAINER_multihashmap_iterate(t->first_hops, &iterate_free, NULL); GNUNET_CONTAINER_multihashmap_destroy(t->first_hops); GNUNET_free(t); }