/* vim: set expandtab ts=4 sw=4: */ /* * You may redistribute this program and/or modify it under the terms of * the GNU General Public License as published by the Free Software Foundation, * either version 3 of the License, or (at your option) any later version. * * This program 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 this program. If not, see . */ #include "dht/Address.h" #include "dht/dhtcore/Node.h" #include "dht/dhtcore/NodeStore.h" #include "dht/dhtcore/NodeList.h" #include "util/AddrTools.h" #include "util/Assert.h" #include "util/Bits.h" #include "util/log/Log.h" #include "util/version/Version.h" #include "switch/NumberCompress.h" #include "switch/LabelSplicer.h" #include "util/Gcc.h" #include "util/Defined.h" #include "util/Endian.h" #include "util/events/Time.h" #include /** A list of DHT nodes. */ struct NodeStore_pvt { struct NodeStore pub; /** A fake link where we are both the parent and child. */ struct Node_Link* selfLink; /** A tree containing all nodes ordered by ipv6 */ struct NodeRBTree { struct Node_Two* rbh_root; } nodeTree; struct Allocator* alloc; /** * The links to be freed next time freePendingLinks() is called. */ struct Node_Link* linksToFree; /** Nodes which have very likely been reset. */ struct RumorMill* renumberMill; /** The means for this node store to log. */ struct Log* logger; /** To track time, for e.g. figuring out when nodes were last pinged */ struct EventBase* eventBase; Identity }; // My memory is really bad #define A_COMES_FIRST 1 #define B_COMES_FIRST -1 static int comparePeers(const struct Node_Link* la, const struct Node_Link* lb) { Identity_check(lb); uint64_t a = la->cannonicalLabel; uint64_t b = lb->cannonicalLabel; int log2Diff = Bits_log2x64(b) - Bits_log2x64(a); if (log2Diff) { return log2Diff; } if (Bits_bitReverse64(a) < Bits_bitReverse64(b)) { return A_COMES_FIRST; } else if (a == b) { return 0; } return B_COMES_FIRST; } RB_GENERATE_STATIC(PeerRBTree, Node_Link, peerTree, comparePeers) static int compareNodes(const struct Node_Two* na, const struct Node_Two* nb) { Identity_check(nb); int ret; ret = Address_xorcmp(0, na->address.ip6.ints.one_be, nb->address.ip6.ints.one_be); if (ret) { return ret; } ret = Address_xorcmp(0, na->address.ip6.ints.two_be, nb->address.ip6.ints.two_be); if (ret) { return ret; } ret = Address_xorcmp(0, na->address.ip6.ints.three_be, nb->address.ip6.ints.three_be); if (ret) { return ret; } ret = Address_xorcmp(0, na->address.ip6.ints.four_be, nb->address.ip6.ints.four_be); return ret; } RB_GENERATE_STATIC(NodeRBTree, Node_Two, nodeTree, compareNodes) static void freeLink(struct Node_Link* link, struct NodeStore_pvt* store) { Allocator_realloc(store->alloc, link, 0); store->pub.linkCount--; } static struct Node_Link* getLink(struct NodeStore_pvt* store) { store->pub.linkCount++; return Allocator_calloc(store->alloc, sizeof(struct Node_Link), 1); } static void logLink(struct NodeStore_pvt* store, struct Node_Link* link, char* message) { if (!Defined(Log_DEBUG)) { return; } uint8_t parent[40]; uint8_t child[40]; AddrTools_printIp(parent, link->parent->address.ip6.bytes); AddrTools_printIp(child, link->child->address.ip6.bytes); uint8_t path[20]; AddrTools_printPath(path, link->cannonicalLabel); Log_debug(store->logger, "link[%s]->[%s] [%s] %s", parent, child, path, message); } static void _checkNode(struct Node_Two* node, struct NodeStore_pvt* store, char* file, int line) { if (!Defined(PARANOIA)) { return; } Assert_true(node->address.path == EncodingScheme_convertLabel(store->pub.selfNode->encodingScheme, node->address.path, EncodingScheme_convertLabel_convertTo_CANNONICAL)); struct Node_Link* link; for (link = node->reversePeers; link; link = link->nextPeer) { Assert_fileLine(link->child == node, file, line); Assert_fileLine(RB_FIND(PeerRBTree, &link->parent->peerTree, link) == link, file, line); // This is for you arc int ok = 0; struct Node_Link* nl = NULL; while ((nl = NodeStore_nextLink(link->parent, nl))) { if (nl == link) { ok = 1; break; } } Assert_fileLine(ok, file, line); // } struct Node_Link* lastLink = NULL; RB_FOREACH_REVERSE(link, PeerRBTree, &node->peerTree) { Assert_fileLine(!EncodingScheme_isSelfRoute(link->parent->encodingScheme, link->cannonicalLabel) || link == store->selfLink, file, line); Assert_fileLine(Node_getBestParent(node) || Node_getBestParent(link->child) != link, file, line); Assert_fileLine(link->parent == node, file, line); Assert_fileLine(link->child != node || link == store->selfLink, file, line); Assert_fileLine(!lastLink || link->cannonicalLabel != lastLink->cannonicalLabel, file, line); Assert_fileLine(link->cannonicalLabel < UINT64_MAX && link->cannonicalLabel > 0, file, line); // Make sure there isn't a link which has a completely wacky link encoding number. // Also make sure links are all flushed if a node is discovered to have changed it's // encoding scheme... Assert_fileLine(link->inverseLinkEncodingFormNumber < link->child->encodingScheme->count, file, line); struct Node_Link* rlink = NULL; for (rlink = link->child->reversePeers; rlink; rlink = rlink->nextPeer) { if (rlink == link) { break; } } Assert_fileLine(rlink && "child contains reverse link", file, line); lastLink = link; } if (Node_getBestParent(node)) { Assert_fileLine(Node_getReach(Node_getBestParent(node)->parent) > Node_getReach(node) || node == store->pub.selfNode, file, line); Assert_fileLine(node->address.path != UINT64_MAX, file, line); Assert_fileLine(Node_getReach(node) > 0, file, line); struct Node_Two* nn = node; do { Assert_fileLine( LabelSplicer_routesThrough(nn->address.path, Node_getBestParent(nn)->parent->address.path), file, line ); nn = Node_getBestParent(nn)->parent; } while (nn != store->pub.selfNode); } else { Assert_fileLine(node->address.path == UINT64_MAX, file, line); Assert_fileLine(Node_getReach(node) == 0, file, line); } } #define checkNode(node, store) _checkNode(node, store, Gcc_SHORT_FILE, Gcc_LINE) static void _verifyNode(struct Node_Two* node, struct NodeStore_pvt* store, char* file, int line) { if (!Defined(PARANOIA)) { return; } // #1 check the node (do the basic checks) _checkNode(node, store, file, line); // #2 make sure all of the node's outgoing links are split properly struct Node_Link* link = NULL; RB_FOREACH_REVERSE(link, PeerRBTree, &node->peerTree) { // make sure any peers of this node are split properly struct Node_Link* linkB = link; struct Node_Link* linkC = link; RB_FOREACH_REVERSE_FROM(linkB, PeerRBTree, linkC) { if (linkB == link || link == store->selfLink) { continue; } Assert_fileLine( !LabelSplicer_routesThrough(linkB->cannonicalLabel, link->cannonicalLabel), file, line ); } Assert_true(!link->nextInSplitList); } // #3 make sure looking for the node by address will actually find the correct node. if (Node_getBestParent(node)) { Assert_fileLine(node == NodeStore_closestNode(&store->pub, node->address.path), file, line); } // #4 no persistant markings are allowed. Assert_true(!node->marked); } #define verifyNode(node, store) _verifyNode(node, store, Gcc_SHORT_FILE, Gcc_LINE) // Verify is more thorough than check because it makes sure all links are split properly. static void _verify(struct NodeStore_pvt* store, char* file, int line) { if (!Defined(PARANOIA)) { return; } Assert_true(Node_getBestParent(store->pub.selfNode) == store->selfLink || !store->selfLink); int linkedNodes = 0; struct Node_Two* nn = NULL; RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { _verifyNode(nn, store, file, line); if (Node_getBestParent(nn)) { linkedNodes++; } } Assert_fileLine(linkedNodes == store->pub.linkedNodes, file, line); } #define verify(store) _verify(store, Gcc_SHORT_FILE, Gcc_LINE) static void _check(struct NodeStore_pvt* store, char* file, int line) { if (!Defined(PARANOIA)) { return; } Assert_true(Node_getBestParent(store->pub.selfNode) == store->selfLink || !store->selfLink); struct Node_Two* nn = NULL; RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { _checkNode(nn, store, file, line); } } #define check(store) _check(store, Gcc_SHORT_FILE, Gcc_LINE) /** * Extend a route by splicing on another link. * This will modify the Encoding Form of the first Director in next section of the route to make * it's size greater than or equal to the size of the return route through the parent node in the * link. * * @param routeToParent the label for reaching the parent node * @param parentScheme the label encoding scheme used by the parent node * @param routeParentToChild the cannonicalLabel for the link from parent to child * @param previousLinkEncoding the encoding used for the parent's interface back to the grandparent * @return a converted/spliced label or extendRoute_INVALID if it happens that the parent * or ~0 if the label is too long to represent. */ #define extendRoute_INVALID (((uint64_t)~0)-1) static uint64_t extendRoute(uint64_t routeToParent, struct EncodingScheme* parentScheme, uint64_t routeParentToChild, int previousLinkEncoding) { Assert_true(routeParentToChild != EncodingScheme_convertLabel_INVALID); // Make sure they didn't send us a 'silly' route. int nextLinkEncoding = EncodingScheme_getFormNum(parentScheme, routeParentToChild); if (nextLinkEncoding == EncodingScheme_getFormNum_INVALID) { return extendRoute_INVALID; } // If the encoding to get to the parent uses more bits than the encoding to get from parent // to child, we need to change the encoding... if (previousLinkEncoding > nextLinkEncoding) { routeParentToChild = EncodingScheme_convertLabel(parentScheme, routeParentToChild, previousLinkEncoding); Assert_true(routeParentToChild != EncodingScheme_convertLabel_INVALID); } return LabelSplicer_splice(routeParentToChild, routeToParent); } static void update(struct Node_Link* link, int64_t linkStateDiff, struct NodeStore_pvt* store) { if (linkStateDiff + link->linkState > UINT32_MAX) { link->linkState = UINT32_MAX; //logLink(store, link, "link state set to maximum"); } else if (linkStateDiff + link->linkState < 0) { link->linkState = 0; logLink(store, link, "link state set to zero"); } else { link->linkState += linkStateDiff; } } static bool isPeer(struct Node_Two* node, struct NodeStore_pvt* store) { if (!Node_getBestParent(node)) { return false; } return Node_getBestParent(node)->parent == store->pub.selfNode && LabelSplicer_isOneHop(Node_getBestParent(node)->cannonicalLabel); } static void unreachable(struct Node_Two* node, struct NodeStore_pvt* store) { struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &node->peerTree) { if (Node_getBestParent(next->child) == next) { unreachable(next->child, store); } } // We think the link is down, so reset the link state. struct Node_Link* bp = Node_getBestParent(node); if (bp) { update(bp, -UINT32_MAX, store); store->pub.linkedNodes--; } Node_setParentReachAndPath(node, NULL, 0, UINT64_MAX); } /** Adds the reach of path A->B to path B->C to get the expected reach of A->C. */ static uint32_t addReach(uint32_t reachAB, uint32_t reachBC) { uint64_t b = reachAB; uint64_t c = reachBC; uint64_t reachAC = (b * c) / (b + c); if (reachAC > UINT32_MAX) { return UINT32_MAX; } return reachAC; } /** Subtracts the reach of path A->B from path A->B->C, to get reach of B->C. */ static uint32_t subReach(uint32_t reachAB, uint32_t reachAC) { if (reachAB <= reachAC) { return UINT32_MAX; } uint64_t b = reachAB; uint64_t c = reachAC; uint64_t reachBC = (b * c) / (b - c); if (reachBC > UINT32_MAX) { return UINT32_MAX; } return reachBC; } /** * This is called when we have no idea what the reach should be for the next hop * because the path we previously used to get to it is broken and we need to use * a different one. Take a somewhat educated guess as to what it might be in a way * that will make the reach non-zero. */ static uint32_t guessReachOfChild(struct Node_Link* link) { uint32_t r; if (LabelSplicer_isOneHop(link->cannonicalLabel)) { // Single-hop link, so guess that it's 3/4 the parent's reach r = (Node_getReach(link->parent) * 3) / 4; } else { // Multi-hop link, so let's assume 1/2 the parent's reach. r = Node_getReach(link->parent) / 2; } if (r < (1<<12)) { r = Node_getReach(link->parent) - 1; } else if (r < (1<<16)) { r = Node_getReach(link->parent) - Bits_log2x64(link->cannonicalLabel); } // Educated guess, parent's latency + link's latency (neither of which is known perfectly). uint32_t guess = addReach(Node_getReach(link->parent), link->linkState); if (guess < Node_getReach(link->parent) && guess > r) { // Our guess is sensible, so use it. r = guess; } // Try to reduce oscillation based on guesses. struct Node_Link* bp = Node_getBestParent(link->child); if (bp && bp != link) { uint32_t bpGuess = guessReachOfChild(bp); if (r > bpGuess) { r = bpGuess; } } Assert_true(r < Node_getReach(link->parent) && r != 0); return r; } static int updateBestParentCycle(struct Node_Link* newBestLink, int cycle, int limit, uint32_t nextReach, struct NodeStore_pvt* store) { Assert_true(cycle < 1000); struct Node_Two* node = newBestLink->child; if (cycle < limit) { int total = 0; struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &node->peerTree) { if (Node_getBestParent(next->child) == next && next->child != node) { total += updateBestParentCycle(next, cycle+1, limit, nextReach, store); } } return total; } struct Node_Two* newBest = newBestLink->parent; uint64_t bestPath = extendRoute(newBest->address.path, newBest->encodingScheme, newBestLink->cannonicalLabel, Node_getBestParent(newBest)->inverseLinkEncodingFormNumber); if (bestPath == UINT64_MAX) { // too long to splice. unreachable(node, store); return 1; } Assert_true(bestPath != extendRoute_INVALID); /*if (Defined(Log_DEBUG)) { if (node->address.path != bestPath) { uint8_t pathStr[20]; AddrTools_printPath(pathStr, bestPath); uint8_t addrStr[40]; AddrTools_printIp(addrStr, node->address.ip6.bytes); Log_debug(store->logger, "New best path [%s@%s]", addrStr, pathStr); } }*/ if (limit) { // We're only altering the reach of the top node in the chain. // If we want to deduce reach of further nodes along the path, here's the place. nextReach = Node_getReach(node); } if (!Node_getBestParent(node)) { store->pub.linkedNodes++; } Node_setParentReachAndPath(node, newBestLink, nextReach, bestPath); checkNode(node, store); return 1; } /** * Update the best parent of this node. * propigating path changes out through the tree. * * @param newBestParent the new best link to the node. The affected node is newBestParent->child. * @param nextReach the reach to set the node to. * @param store the nodestore. */ static void updateBestParent(struct Node_Link* newBestParent, uint32_t nextReach, struct NodeStore_pvt* store) { check(store); Assert_true(newBestParent); for (int i = 0; i < 10000; i++) { if (!updateBestParentCycle(newBestParent, 0, i, nextReach, store)) { check(store); return; } } Assert_true(0); } static void handleGoodNews(struct Node_Two* node, uint32_t newReach, struct NodeStore_pvt* store) { // TODO(cjd): Paths longer than 1024 will blow up, handle more gracefully Assert_true(newReach != UINT32_MAX); Assert_true(newReach > Node_getReach(node)); // The nodestore thinks it's unreachable, we can't very well update the reach. if (Node_getBestParent(node) == NULL) { return; } struct Node_Two* bp = Node_getBestParent(node)->parent; if (newReach+1 > Node_getReach(bp)) { handleGoodNews(bp, newReach+1, store); } Node_setReach(node, newReach); struct Node_Link* link = NULL; RB_FOREACH_REVERSE(link, PeerRBTree, &node->peerTree) { Identity_check(link); struct Node_Two* child = link->child; struct Node_Link* childBestParent = Node_getBestParent(child); if (!childBestParent || Node_getReach(childBestParent->parent) < newReach) { uint32_t nextReach = guessReachOfChild(link); if (Node_getReach(child) > nextReach) { continue; } updateBestParent(link, nextReach, store); } } } /** * The news has hit (in handleBadNewsOne) and now all of the nodes in the affected zone have * been knocked down. Now lets see if there's a better path for any of them. */ static void handleBadNewsTwo(struct Node_Link* link, struct NodeStore_pvt* store, bool firstCall) { struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &link->child->peerTree) { if (!next) { continue; } if (Node_getBestParent(next->child) != next) { continue; } if (next == store->selfLink) { continue; } handleBadNewsTwo(next, store, false); } if (firstCall) { return; } Assert_true(Node_getBestParent(link->child) == link); struct Node_Two* node = link->child; struct Node_Link* rp = link->child->reversePeers; struct Node_Link* best = Node_getBestParent(node); while (rp) { if (Node_getReach(rp->parent) >= Node_getReach(best->parent)) { if (Node_getReach(rp->parent) > Node_getReach(best->parent) || rp->parent->address.path < best->parent->address.path) { best = rp; } } rp = rp->nextPeer; } if (best == Node_getBestParent(node)) { return; } uint32_t nextReach = guessReachOfChild(best); if (nextReach <= Node_getReach(node)) { return; } Assert_true(Node_getReach(node) < Node_getReach(best->parent)); check(store); updateBestParent(best, nextReach, store); check(store); } /** * First thing we do is knock down everybody's reach. * This way they don't all cling to eachother for safety making * endless routing loops and stupid processing. */ static void handleBadNewsOne(struct Node_Link* link, uint32_t newReach, struct NodeStore_pvt* store) { struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &link->child->peerTree) { if (Node_getBestParent(next->child) != next) { continue; } if (next == store->selfLink) { continue; } if (Node_getReach(next->child) < newReach) { continue; } handleBadNewsOne(next, newReach ? (newReach - 1) : 0, store); } Assert_true(link->child != store->pub.selfNode); if (!newReach) { unreachable(link->child, store); } else { Node_setReach(link->child, newReach); } } static void handleBadNews(struct Node_Two* node, uint32_t newReach, struct NodeStore_pvt* store) { Assert_true(newReach < Node_getReach(node)); // might be destroyed by handleBadNewsOne() struct Node_Link* bp = Node_getBestParent(node); // no bestParent implies a reach of 0 Assert_true(bp && bp != store->selfLink); handleBadNewsOne(bp, newReach, store); check(store); handleBadNewsTwo(bp, store, true); check(store); } static void handleNews(struct Node_Two* node, uint32_t newReach, struct NodeStore_pvt* store) { // This is because reach is used to prevent loops so it must be 1 more for each hop closer // to the root. if (newReach > (UINT32_MAX - 1024)) { newReach = (UINT32_MAX - 1024); } check(store); if (newReach < Node_getReach(node)) { handleBadNews(node, newReach, store); check(store); } else if (newReach > Node_getReach(node)) { handleGoodNews(node, newReach, store); check(store); } } void NodeStore_unlinkNodes(struct NodeStore* nodeStore, struct Node_Link* link) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*) nodeStore); struct Node_Two* child = Identity_check(link->child); struct Node_Two* parent = Identity_check(link->parent); check(store); if (parent == store->pub.selfNode) { // yuh ok if (link == store->selfLink) { return; } Assert_true(LabelSplicer_isOneHop(link->cannonicalLabel)); store->pub.peerCount--; if (Defined(Log_INFO)) { uint8_t addr[60]; Address_print(addr, &child->address); Log_info(store->logger, "Direct peer [%s] has been unlinked", addr); } } // Change the best parent and path if necessary if (Node_getBestParent(child) == link) { handleBadNews(child, 0, store); } if (Node_getBestParent(child) == link) { unreachable(child, store); } check(store); // Remove the entry from the reversePeers struct Node_Link* current = child->reversePeers; struct Node_Link** currentP = &child->reversePeers; while (current) { if (current == link) { *currentP = current->nextPeer; break; } currentP = &(current->nextPeer); current = *currentP; } Assert_true(current); // Remove the RBTree entry Assert_ifParanoid(link == RB_FIND(PeerRBTree, &parent->peerTree, link)); RB_REMOVE(PeerRBTree, &parent->peerTree, link); link->nextPeer = store->linksToFree; store->linksToFree = link; // prevent double-free of link. link->parent = NULL; link->child = NULL; check(store); } /** * Link two nodes in the graph together. * If a parent of the child node is also a parent of the parent node, they are * unlinked (the link is split and the child is inserted in the middle). * * @param parent the current end of the graph * @param child the new node to extend the graph * @param cannonicalLabel the label for getting from the parent to the child. * @param linkStateDiff how much to change the link state for this link. * @param store */ static struct Node_Link* linkNodes(struct Node_Two* parent, struct Node_Two* child, uint64_t cannonicalLabel, int64_t linkStateDiff, int inverseLinkEncodingFormNumber, uint64_t discoveredPath, struct NodeStore_pvt* store) { check(store); if (Defined(Log_DEBUG)) { uint8_t parentIp[40]; uint8_t childIp[40]; AddrTools_printIp(parentIp, parent->address.ip6.bytes); AddrTools_printIp(childIp, child->address.ip6.bytes); uint8_t printedLabel[20]; AddrTools_printPath(printedLabel, cannonicalLabel); Log_debug(store->logger, "Linking [%s] with [%s] with label fragment [%s]", parentIp, childIp, printedLabel); } // It's ok to link a node with itself via some loopey route. // in practice it should never actually be used and it might yield some interesting // information when the link is split, self-routes are not allowed unless the self // link is being set up :) Assert_true(cannonicalLabel != 1 || store->selfLink == NULL); if (Defined(PARANOIA)) { uint64_t definitelyCannonical = EncodingScheme_convertLabel(parent->encodingScheme, cannonicalLabel, EncodingScheme_convertLabel_convertTo_CANNONICAL); Assert_true(definitelyCannonical == cannonicalLabel); } { struct Node_Link* link; RB_FOREACH_REVERSE(link, PeerRBTree, &parent->peerTree) { Identity_check(link); if (link->child == child) { if (link->cannonicalLabel != cannonicalLabel) { // multiple paths between A and B are ok because they // will have divergent paths following the first director. continue; } else if (link->inverseLinkEncodingFormNumber != inverseLinkEncodingFormNumber) { logLink(store, link, "Relinking nodes with different encoding form"); // This can happen when C renumbers but B->C is the same because B did // not renumber, EG: if C restarts. link->inverseLinkEncodingFormNumber = inverseLinkEncodingFormNumber; } update(link, linkStateDiff, store); return link; } } } if (Defined(PARANOIA)) { struct Node_Link dummy = { .cannonicalLabel = cannonicalLabel }; struct Node_Link* link = Identity_ncheck(RB_FIND(PeerRBTree, &parent->peerTree, &dummy)); if (link) { logLink(store, link, "Attempted to create alternate link with same label!"); Assert_true(0); return link; } } Assert_true(cannonicalLabel <= discoveredPath); struct Node_Link* link = getLink(store); // set it up link->cannonicalLabel = cannonicalLabel; link->inverseLinkEncodingFormNumber = inverseLinkEncodingFormNumber; link->child = child; link->parent = parent; link->discoveredPath = discoveredPath; link->linkState = 0; link->timeLastSeen = Time_currentTimeMilliseconds(store->eventBase); Identity_set(link); // reverse link link->nextPeer = child->reversePeers; child->reversePeers = link; // forward link Assert_ifParanoid(!RB_FIND(PeerRBTree, &parent->peerTree, link)); RB_INSERT(PeerRBTree, &parent->peerTree, link); if (!Node_getBestParent(child)) { if (Node_getBestParent(parent)) { updateBestParent(link, guessReachOfChild(link), store); } else { unreachable(child, store); } } // update the child's link state and possibly change it's preferred path update(link, linkStateDiff, store); if (parent == store->pub.selfNode && child != store->pub.selfNode) { Assert_true(LabelSplicer_isOneHop(cannonicalLabel)); store->pub.peerCount++; if (Defined(Log_DEBUG)) { uint8_t addr[60]; Address_print(addr, &child->address); Log_info(store->logger, "Direct peer [%s] has been linked", addr); } } check(store); return link; } #define removeLinkFromLabel_IMPOSSIBLE UINT64_MAX #define removeLinkFromLabel_OVERSIZE (UINT64_MAX-1) #define removeLinkFromLabel_ERR(x) (((uint64_t)x) >> 63) // TODO(cjd): This does not depend on nodeStore or alter the link, consider moving to Node.c static uint64_t removeLinkFromLabel(struct Node_Link* link, uint64_t label) { // First we splice off the parent's Director leaving the child's Director. uint64_t unspliced = LabelSplicer_unsplice(label, link->cannonicalLabel); int formNum = EncodingScheme_getFormNum(link->child->encodingScheme, unspliced); if (formNum < link->inverseLinkEncodingFormNumber) { // Can't get there from here. return removeLinkFromLabel_IMPOSSIBLE; } uint64_t cannonical = EncodingScheme_convertLabel(link->child->encodingScheme, unspliced, EncodingScheme_convertLabel_convertTo_CANNONICAL); // Check that they didn't waste space by sending an oversize encoding form. if (formNum > link->inverseLinkEncodingFormNumber && cannonical != unspliced) { return removeLinkFromLabel_OVERSIZE; } Assert_true(cannonical != EncodingScheme_convertLabel_INVALID); return cannonical; } /** * Find the next hop on a given path. * Given a label representing a path from parentLink to some destination, set * outLink to the first link along that journey and return the path from outLink * to the original destination. * Feeding outLink back in to parentLink and the return value back into label argument * will allow you to iteratively walk a path. * * @param label the path from parentLink to some unspecified destination. * @param outLink a pointer to a location which will receive the first link in the path. * @param parentLink the link where to begin the trek. * @param store * @return a label which would take you from the node in memory location outLink to the * destination provided by the label argument. OR: firstHopInPath_INVALID if the * label argument traverces a node whose encoding scheme is inconsistent with * the label. OR: firstHopInPath_NO_NEXT_LINK if there are no *known* further * links along the path. If the result is firstHopInPath_INVALID, outLink will * still be set to the node. Use firstHopInPath_ERR() to check if the return * is an error code. */ #define firstHopInPath_INVALID UINT64_MAX #define firstHopInPath_NO_NEXT_LINK (UINT64_MAX-1) #define firstHopInPath_ERR(path) (path >= firstHopInPath_NO_NEXT_LINK) static uint64_t firstHopInPath(uint64_t label, struct Node_Link** outLink, struct Node_Link* parentLink, struct NodeStore_pvt* store) { // Then we search for the next peer in the path // RB_NFIND will find a link for which we know that no link before it is in the path. // Unfortunately I have not found a way to store links in a tree where the search time // is less than O(n) where n = peers of a given node. struct Node_Link tmpl = { .cannonicalLabel = label }; struct Node_Link* nextLink = Identity_ncheck(RB_NFIND(PeerRBTree, &parentLink->child->peerTree, &tmpl)); // Now we walk back through the potential candidates looking for a path which it routes though. while (nextLink && !LabelSplicer_routesThrough(label, nextLink->cannonicalLabel)) { nextLink = Identity_ncheck(RB_NEXT(PeerRBTree, NULL, nextLink)); } // This node has no peers, if it's us then it always has a peer (which is the selfLink) if (!nextLink || nextLink == store->selfLink) { return firstHopInPath_NO_NEXT_LINK; } // check for a looping link, this should never happen but adding the assert helps me // refactor this function a little more agressively. Assert_true(nextLink != parentLink); if (label == nextLink->cannonicalLabel) { //logLink(store, nextLink, "Exact match"); *outLink = nextLink; return 1; } if (!LabelSplicer_routesThrough(label, nextLink->cannonicalLabel)) { // child of next link is not in the path, we reached the end. return firstHopInPath_NO_NEXT_LINK; } *outLink = nextLink; // Cannoicalize the child's Director label = removeLinkFromLabel(nextLink, label); if (removeLinkFromLabel_ERR(label)) { return firstHopInPath_INVALID; } return label; } #define findClosest_INVALID (~((uint64_t)0)) static uint64_t findClosest(uint64_t path, struct Node_Link** output, struct Node_Link* parentLink, struct NodeStore_pvt* store) { for (;;) { struct Node_Link* nextLink = NULL; uint64_t nextPath = firstHopInPath(path, &nextLink, parentLink, store); if (nextPath == firstHopInPath_NO_NEXT_LINK) { *output = parentLink; return path; } if (firstHopInPath_INVALID == nextPath) { return findClosest_INVALID; } Assert_true(nextLink); path = nextPath; parentLink = nextLink; } } static struct Node_Two* nodeForIp(struct NodeStore_pvt* store, uint8_t ip[16]) { struct Node_Two fakeNode; Identity_set(&fakeNode); Bits_memcpyConst(fakeNode.address.ip6.bytes, ip, 16); return Identity_ncheck(RB_FIND(NodeRBTree, &store->nodeTree, &fakeNode)); } static void freePendingLinks(struct NodeStore_pvt* store) { struct Node_Link* link; while ((link = store->linksToFree)) { store->linksToFree = link->nextPeer; freeLink(link, store); } } static struct Node_Link* discoverLinkC(struct NodeStore_pvt* store, struct Node_Link* closestKnown, uint64_t pathKnownParentChild, struct Node_Two* child, uint64_t discoveredPath, int inverseLinkEncodingFormNumber) { // Make sure this link cannot be split before beginning. struct Node_Link* closest = NULL; uint64_t pathParentChild = findClosest(pathKnownParentChild, &closest, closestKnown, store); if (pathParentChild == findClosest_INVALID) { return NULL; } struct Node_Two* parent = closest->child; if (Defined(Log_DEBUG)) { uint8_t parentStr[40]; uint8_t childStr[40]; uint8_t pathStr[20]; AddrTools_printIp(parentStr, parent->address.ip6.bytes); AddrTools_printIp(childStr, child->address.ip6.bytes); AddrTools_printPath(pathStr, pathParentChild); Log_debug(store->logger, "discoverLinkC( [%s]->[%s] [%s] )", parentStr, childStr, pathStr); } if (closest == store->selfLink && !LabelSplicer_isOneHop(pathParentChild)) { Log_debug(store->logger, "Attempting to create a link with no parent peer"); return NULL; } if (parent == child) { if (pathParentChild == 1) { // Link is already known. update(closest, 0, store); //Log_debug(store->logger, "Already known"); return closest; } Log_debug(store->logger, "Loopey route"); // lets not bother storing this link, a link with the same parent and child is // invalid according to verify() and it's just going to take up space in the store // we'll return closest which is a perfectly valid path to the same node. // We could reasonably return the closest since it is the same node but it causes // problems with an assertion in discoverLink. return NULL; } if (EncodingScheme_isSelfRoute(parent->encodingScheme, pathParentChild)) { logLink(store, closest, "Node at end of path appears to have changed"); // This should never happen for a direct peer or for a direct decendent in a split link. // This sometimes triggers because a link is split which contains an invalid encoding // somewhere in the middle. // It is not harmful to remove it becaue the route is not re-added. Assert_ifTesting(closestKnown != closest); // This probably means the parent node has renumbered it's switch... RumorMill_addNode(store->renumberMill, &closest->parent->address); check(store); // But it's possible someone is just lieing to us. return NULL; } // link parent to child // // ACKTUNG: From this point forward, the nodeStore is in an invalid state, calls to _verify() // will fail (calls to _check() will still succeed). We have linked parent with child // but we have not split all of the splitLinks from parent. // // TODO(cjd): linking every node with 0 link state, this can't be right. struct Node_Link* parentLink = linkNodes(parent, child, pathParentChild, 0, inverseLinkEncodingFormNumber, discoveredPath, store); if (!RB_FIND(NodeRBTree, &store->nodeTree, child)) { checkNode(child, store); RB_INSERT(NodeRBTree, &store->nodeTree, child); store->pub.nodeCount++; } check(store); return parentLink; } static void fixLink(struct Node_Link* parentLink, struct Node_Link** outLinks, struct NodeStore_pvt* store) { int verifyOrder = 0; // Check whether the parent is already linked with a node which is "behind" the child. // splitLink appears to be a "sibling link" to the closest->node link but in reality the // splitLink link should be split and node should be inserted in the middle. struct Node_Link* splitLink = RB_MIN(PeerRBTree, &parentLink->parent->peerTree); while (splitLink) { if (splitLink == parentLink) { if (Defined(PARANOIA)) { verifyOrder = 1; splitLink = PeerRBTree_RB_NEXT(splitLink); continue; } else { // Since they're in order, definitely not found. break; } } if (!LabelSplicer_routesThrough(splitLink->cannonicalLabel, parentLink->cannonicalLabel)) { splitLink = PeerRBTree_RB_NEXT(splitLink); continue; } if (Defined(PARANOIA)) { Assert_true(!verifyOrder); } struct Node_Two* grandChild = splitLink->child; if (parentLink->child == grandChild) { // loopey route, kill it and let the bestParent pivit over to parentLink } else { logLink(store, splitLink, "Splitting link"); // unsplice and cannonicalize so we now have a path from child to grandchild uint64_t childToGrandchild = LabelSplicer_unsplice(splitLink->cannonicalLabel, parentLink->cannonicalLabel); childToGrandchild = EncodingScheme_convertLabel(parentLink->child->encodingScheme, childToGrandchild, EncodingScheme_convertLabel_convertTo_CANNONICAL); Assert_true(childToGrandchild < UINT64_MAX); Assert_true(childToGrandchild != 1); Assert_true(splitLink->cannonicalLabel != parentLink->cannonicalLabel); // We forgot what was the discovered path for the link when we split (destroyed) // it so we'll just assume the worst among these two possibilities. // There is an assertion that discoveredPath is never < cannonicalLabel so we must. uint64_t discoveredPath = parentLink->discoveredPath; if (childToGrandchild > discoveredPath) { discoveredPath = childToGrandchild; } struct Node_Link* childLink = discoverLinkC(store, parentLink, childToGrandchild, grandChild, discoveredPath, splitLink->inverseLinkEncodingFormNumber); if (childLink) { // Order the list so that the next set of links will be split from // smallest to largest and nothing will ever be split twice. for (struct Node_Link** x = outLinks;; x = &(*x)->nextInSplitList) { if (*x == childLink) { break; } if (*x && (*x)->cannonicalLabel <= childLink->cannonicalLabel) { continue; } Assert_true(!childLink->nextInSplitList); childLink->nextInSplitList = *x; *x = childLink; break; } } } check(store); struct Node_Link* next = PeerRBTree_RB_NEXT(splitLink); NodeStore_unlinkNodes(&store->pub, splitLink); splitLink = next; } } static void fixLinks(struct Node_Link* parentLinkList, struct Node_Link** outLinks, struct NodeStore_pvt* store) { while (parentLinkList) { struct Node_Link* next = parentLinkList->nextInSplitList; parentLinkList->nextInSplitList = NULL; // else the parent link has been trashed by splitting another link. if (parentLinkList->child) { fixLink(parentLinkList, outLinks, store); } parentLinkList = next; } } static struct Node_Link* discoverLink(struct NodeStore_pvt* store, uint64_t path, struct Node_Two* child, int inverseLinkEncodingFormNumber) { struct Node_Link* link = discoverLinkC(store, store->selfLink, path, child, path, inverseLinkEncodingFormNumber); if (!link) { return NULL; } uint64_t pathParentChild = findClosest(path, &link, store->selfLink, store); // This should always be 1 because the link is gone only because it was just split! Assert_true(pathParentChild == 1); struct Node_Link* ol = NULL; struct Node_Link* nl = NULL; fixLinks(link, &ol, store); for (;;) { if (ol) { fixLinks(ol, &nl, store); ol = NULL; } else if (nl) { fixLinks(nl, &ol, store); nl = NULL; } else { break; } } verify(store); return link; } static struct Node_Two* whichIsWorse(struct Node_Two* one, struct Node_Two* two, struct NodeStore_pvt* store) { // a peer is nevar worse int peers = isPeer(one, store) - isPeer(two, store); if (peers) { return (peers > 0) ? two : one; } if (one->address.protocolVersion != two->address.protocolVersion) { if (one->address.protocolVersion < Version_CURRENT_PROTOCOL) { if (two->address.protocolVersion >= Version_CURRENT_PROTOCOL) { return one; } } else if (two->address.protocolVersion < Version_CURRENT_PROTOCOL) { if (one->address.protocolVersion >= Version_CURRENT_PROTOCOL) { return two; } } } if (Node_getReach(one) < Node_getReach(two)) { return one; } if (Node_getReach(two) < Node_getReach(one)) { return two; } if (Address_closest(&store->pub.selfNode->address, &one->address, &two->address) > 0) { return one; } return two; } struct NodeList* NodeStore_getNodesForBucket(struct NodeStore* nodeStore, struct Allocator* allocator, uint16_t bucket, const uint32_t count) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct NodeList* nodeList = Allocator_malloc(allocator, sizeof(struct NodeList)); nodeList->nodes = Allocator_calloc(allocator, count, sizeof(char*)); nodeList->size = 0; struct Node_Two* nn = NULL; RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { if (!Node_getReach(nn)) { continue; } if (NodeStore_bucketForAddr(store->pub.selfAddress, &nn->address) == bucket) { struct Node_Two* newNode = nn; struct Node_Two* tempNode = NULL; for (uint32_t i = 0 ; i < count ; i++) { if (nodeList->size < i+1) { // The list isn't full yet, so insert at the end. nodeList->size = i+1; nodeList->nodes[i] = newNode; break; } if ( (newNode->marked && !nodeList->nodes[i]->marked) || whichIsWorse(nodeList->nodes[i], newNode, store) == nodeList->nodes[i] ) { // If we've already marked nodes because they're a bestParent, // lets give them priority in the bucket since we need to keep // them either way. // Otherwise, decide based on whichIsWorse(). // Insertion sorted list. tempNode = nodeList->nodes[i]; nodeList->nodes[i] = newNode; newNode = tempNode; } } } } return nodeList; } static bool markNodesForBucket(struct NodeStore_pvt* store, uint16_t bucket, const uint32_t count) { struct Allocator* nodeListAlloc = Allocator_child(store->alloc); struct NodeList* nodeList = NodeStore_getNodesForBucket(&store->pub, nodeListAlloc, bucket, count); bool retVal = false; if (nodeList->size > 0) { retVal = true; } for (uint32_t i = 0; i < nodeList->size; i++) { // Now mark the nodes in the list to protect them. Identity_check(nodeList->nodes[i]); nodeList->nodes[i]->marked = 1; } // Cleanup Allocator_free(nodeListAlloc); return retVal; } static void markKeyspaceNodes(struct NodeStore_pvt* store) { for (uint16_t bucket = 0; bucket < NodeStore_bucketNumber ; bucket++) { markNodesForBucket(store, bucket, NodeStore_bucketSize); } } /** * We define the worst node the node with the lowest reach, excluding nodes which are required for * the DHT, and nodes which are somebody's bestParent (only relevant if they're the bestParent of * a DHT-required node, as otherwise their child would always be lower reach). * If two nodes tie (e.g. two unreachable nodes with 0 reach) then the node which is * further from us in keyspace is worse. */ static struct Node_Two* getWorstNode(struct NodeStore_pvt* store) { struct Node_Two* worst = NULL; struct Node_Two* nn = NULL; RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { // first cycle we set markings so markings remain if they are behind us struct Node_Link* parentLink = Node_getBestParent(nn); if (parentLink) { parentLink->parent->marked = 1; } else if (!worst || whichIsWorse(nn, worst, store) == nn) { // this time around we're only addressing nodes which are unreachable. worst = nn; } } if (worst) { RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { if (nn->marked) { nn->marked = false; } } return worst; } // Mark the nodes that we need to protect for keyspace reasons. markKeyspaceNodes(store); RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { if (nn->marked) { nn->marked = false; } else if (!worst || whichIsWorse(nn, worst, store) == nn) { worst = nn; } } if (worst) { return worst; } RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { // third cycle, every node is apparently important but we need to get rid of someone // get whoever is worst if we ignore markings // by definition, this shouldn't be a bestParent, because their children have lower reach // so we're potentially creating a keyspace hole (routing blackhole) when we do this. // TODO(arceliar): protect keyspace, evict the worst bestParent instead? // Would require something like a forgetNode() to splice links together between // that node's bestParent and all its children, before we kill it. if (!worst || whichIsWorse(nn, worst, store) == nn) { worst = nn; } } // somebody has to be at the end of the line, not *everyone* can be someone's best parent! Assert_true(worst); return worst; } static void destroyNode(struct Node_Two* node, struct NodeStore_pvt* store) { // careful, undefined unless debug is enabled... uint8_t address_debug[60]; if (Defined(Log_DEBUG)) { Address_print(address_debug, &node->address); } struct Node_Link* link; RB_FOREACH(link, PeerRBTree, &node->peerTree) { Identity_check(link); NodeStore_unlinkNodes(&store->pub, link); } // If the node has a bestParent, it will be changed a number // of times as we kill off all of it's parent links. // This is an optimization: if (!Defined(PARANOIA)) { store->pub.linkedNodes--; Node_setParentReachAndPath(node, NULL, 0, UINT64_MAX); } link = node->reversePeers; while (link) { struct Node_Link* nextLink = link->nextPeer; NodeStore_unlinkNodes(&store->pub, link); link = nextLink; } Assert_true(!Node_getBestParent(node)); Assert_ifParanoid(node == RB_FIND(NodeRBTree, &store->nodeTree, node)); RB_REMOVE(NodeRBTree, &store->nodeTree, node); store->pub.nodeCount--; Allocator_free(node->alloc); } // Must be at least 2 to avoid multiplying by 0. // If too large, path choice may become unstable due to a guess we make in calcNextReach. // This is fixable by storing reach based on links. A lot of work. // In the mean time, just don't use a large value. #define NodeStore_latencyWindow 8 static uint32_t reachAfterDecay(const uint32_t oldReach) { // Reduce the reach by 1/Xth where X = NodeStore_latencyWindow // This is used to keep a weighted rolling average return (uint64_t)oldReach * (NodeStore_latencyWindow - 1) / (NodeStore_latencyWindow); } static uint32_t reachAfterTimeout(const uint32_t oldReach) { return reachAfterDecay(oldReach); } static uint32_t calcNextReach(const uint32_t oldReach, const uint32_t millisecondsLag) { int64_t out = reachAfterDecay(oldReach) + ((UINT32_MAX / NodeStore_latencyWindow) / (millisecondsLag + 1)); if (!oldReach) { // We don't know the old reach for this path. // If every response comes in after same millisecondsLag, then we expect that the // reach will stabilize to a value of (out * NodeStoare_latencyWindow). // Lets guess what the reach will stabilize to, but try to be a little conservative, // so we don't cause bestParents to switch unless the new route is appreciably better. out = out * (NodeStore_latencyWindow - 1); } // TODO(arceliar): is this safe? Assert_true(out < (UINT32_MAX - 1024) && out > 0); return out; } struct Node_Link* NodeStore_discoverNode(struct NodeStore* nodeStore, struct Address* addr, struct EncodingScheme* scheme, int inverseLinkEncodingFormNumber, uint64_t milliseconds) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); verify(store); // conservative guess of what the reach would stabilize to uint32_t reach = calcNextReach(0, milliseconds); struct Node_Two* child = nodeForIp(store, addr->ip6.bytes); if (Defined(Log_DEBUG)) { uint8_t printedAddr[60]; Address_print(printedAddr, addr); Log_debug(store->logger, "Discover node [%s]", printedAddr); } if (child && child == store->selfLink->child) { return NULL; } if (child && EncodingScheme_compare(child->encodingScheme, scheme)) { // Shit. // Box reset *and* they just updated and changed their encoding scheme. RumorMill_addNode(store->renumberMill, &child->address); if (addr->path > (child->address.path | (child->address.path << 3))) { Log_debug(store->logger, "Node appears to have changed it's encoding scheme " "but the message came from far away and we will not trust it"); return NULL; } else { Log_debug(store->logger, "Node appears to have changed it's encoding scheme " "dropping him from the table and re-inserting"); destroyNode(child, store); child = NULL; } } else if (child && child->address.protocolVersion != addr->protocolVersion) { child->address.protocolVersion = addr->protocolVersion; } struct Allocator* alloc = NULL; if (!child) { alloc = Allocator_child(store->alloc); child = Allocator_calloc(alloc, sizeof(struct Node_Two), 1); child->alloc = alloc; Bits_memcpyConst(&child->address, addr, sizeof(struct Address)); child->encodingScheme = EncodingScheme_clone(scheme, child->alloc); child->timeLastPinged = Time_currentTimeMilliseconds(store->eventBase); Identity_set(child); } struct Node_Link* link = NULL; for (;;) { link = discoverLink(store, addr->path, child, inverseLinkEncodingFormNumber); if (link) { break; } // We might have a broken link in the store which is causing new links to be rejected. // On the other hand, this path might actually be garbage :) // There's a DoS risk in that someone might use garbage paths to evict all of the // existing good paths. // While an attacker can send in a packet, it will necessarily follow a ridiculous path // in order that the path contains one of their nodes. // To resolve this, we'll walk the path looking for the "bad" link, then we'll check that // node to see if the path we took to reach it is actually the *best* path to that node. uint64_t path = addr->path; struct Node_Link* lastLink = store->selfLink; do { struct Node_Link* nextLink = NULL; path = firstHopInPath(path, &nextLink, lastLink, store); lastLink = nextLink; if (path == firstHopInPath_NO_NEXT_LINK) { // discoverNode() failed for some other reason. lastLink = NULL; break; } } while (firstHopInPath_INVALID != path); if (lastLink && LabelSplicer_routesThrough(addr->path, lastLink->child->address.path)) { // checking for sillyness... Assert_true(lastLink != store->selfLink); NodeStore_unlinkNodes(&store->pub, lastLink); continue; } if (alloc) { Allocator_free(alloc); } verify(store); Log_debug(store->logger, "Invalid path"); return NULL; } if (link->parent == store->pub.selfNode && !Node_getBestParent(link->child)) { updateBestParent(link, reach, store); } #ifdef PARANOIA struct Node_Two* parent = link->parent; #endif handleNews(link->child, reach, store); freePendingLinks(store); while (store->pub.nodeCount - store->pub.peerCount > store->pub.nodeCapacity || store->pub.linkCount > store->pub.linkCapacity) { struct Node_Two* worst = getWorstNode(store); if (Defined(Log_DEBUG)) { uint8_t worstAddr[60]; Address_print(worstAddr, &worst->address); Log_debug(store->logger, "store full, removing worst node: [%s] nodes [%d] links [%d]", worstAddr, store->pub.nodeCount, store->pub.linkCount); } Assert_true(!isPeer(worst, store)); if (link && (worst == link->parent || worst == link->child)) { link = NULL; } destroyNode(worst, store); freePendingLinks(store); } verify(store); // This should test that link == NodeStore_linkForPath(path) but that is not guaranteed // to work because links are not healed up when a node is removed from the store Assert_ifParanoid(!link || RB_FIND(PeerRBTree, &parent->peerTree, link) == link); return link; } struct Node_Two* NodeStore_nodeForAddr(struct NodeStore* nodeStore, uint8_t addr[16]) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Two* n = nodeForIp(store, addr); if (n && n->address.path == UINT64_MAX) { if (Defined(Log_DEBUG)) { uint8_t addrStr[40]; AddrTools_printIp(addrStr, n->address.ip6.bytes); Log_debug(store->logger, "No way to represent path to [%s]", addrStr); } return NULL; } return n; } struct Node_Two* NodeStore_closestNode(struct NodeStore* nodeStore, uint64_t path) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* out = NULL; findClosest(path, &out, store->selfLink, store); if (!out) { return NULL; } return Identity_check(out->child); } struct Node_Link* NodeStore_linkForPath(struct NodeStore* nodeStore, uint64_t path) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* out = NULL; uint64_t pathParentChild = findClosest(path, &out, store->selfLink, store); if (pathParentChild != 1) { return NULL; } return Identity_check(out); } struct Node_Link* NodeStore_firstHopInPath(struct NodeStore* nodeStore, uint64_t path, uint64_t* correctedPath, struct Node_Link* startingPoint) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); if (!startingPoint) { startingPoint = store->selfLink; } if (!Node_getBestParent(startingPoint->parent)) { return NULL; } struct Node_Link* out = NULL; path = firstHopInPath(path, &out, startingPoint, store); if (firstHopInPath_ERR(path)) { return NULL; } if (correctedPath) { *correctedPath = path; } return out; } char* NodeStore_getRouteLabel_strerror(uint64_t returnVal) { switch (returnVal) { case NodeStore_getRouteLabel_PARENT_NOT_FOUND: return "NodeStore_getRouteLabel_PARENT_NOT_FOUND"; case NodeStore_getRouteLabel_CHILD_NOT_FOUND: return "NodeStore_getRouteLabel_CHILD_NOT_FOUND"; default: return NULL; } } uint64_t NodeStore_getRouteLabel(struct NodeStore* nodeStore, uint64_t pathToParent, uint64_t pathParentToChild) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* linkToParent; if (findClosest(pathToParent, &linkToParent, store->selfLink, store) != 1) { return NodeStore_getRouteLabel_PARENT_NOT_FOUND; } logLink(store, linkToParent, "NodeStore_getRouteLabel() PARENT"); struct Node_Link* linkToChild = NULL; RB_FOREACH_REVERSE(linkToChild, PeerRBTree, &linkToParent->child->peerTree) { if (pathParentToChild == linkToChild->cannonicalLabel) { if (linkToParent == store->selfLink) { return linkToChild->cannonicalLabel; } // TODO(cjd): this could return ~0 return extendRoute(pathToParent, linkToChild->parent->encodingScheme, linkToChild->cannonicalLabel, linkToParent->inverseLinkEncodingFormNumber); } } return NodeStore_getRouteLabel_CHILD_NOT_FOUND; } uint64_t NodeStore_optimizePath(struct NodeStore* nodeStore, uint64_t path) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* linkToParent; uint64_t next = findClosest(path, &linkToParent, store->selfLink, store); if (next == findClosest_INVALID) { return NodeStore_optimizePath_INVALID; } if (EncodingScheme_isSelfRoute(linkToParent->child->encodingScheme, next)) { // cannoicalize all the other wild ways that they can represent self routes. // TODO(cjd): this has been the source of assert failures and we might be sweeping // a significant bug under the carpet. next = 1; } if (linkToParent == store->selfLink) { if (next == 1) { return 1; } return path; } if (next == 1) { return linkToParent->child->address.path; } struct Node_Link* childBestParent = Node_getBestParent(linkToParent->child); if (childBestParent) { linkToParent = childBestParent; } uint64_t optimized = extendRoute(linkToParent->child->address.path, linkToParent->child->encodingScheme, next, linkToParent->inverseLinkEncodingFormNumber); if (optimized != UINT64_MAX) { return optimized; } if (optimized == extendRoute_INVALID) { if (Defined(Log_DEBUG)) { do { uint8_t pathStr[20]; uint8_t nextStr[20]; uint8_t bestPathStr[20]; AddrTools_printPath(pathStr, path); AddrTools_printPath(nextStr, next); AddrTools_printPath(bestPathStr, linkToParent->child->address.path); Log_debug(store->logger, "Failed to optimize path [%s] with closest known [%s] and " "best path to closest known [%s]", pathStr, nextStr, bestPathStr); } while (0); } return path; } // path is too long... /*if (Defined(Log_DEBUG)) { do { uint8_t pathStr[20]; uint8_t nextStr[20]; uint8_t bestPathStr[20]; AddrTools_printPath(pathStr, path); AddrTools_printPath(nextStr, next); AddrTools_printPath(bestPathStr, linkToParent->child->address.path); Log_debug(store->logger, "Failed to optimize path [%s] with closest known [%s] and best " "path to closest known [%s]", pathStr, nextStr, bestPathStr); } while (0); }*/ return path; } struct Node_Link* NodeStore_nextLink(struct Node_Two* parent, struct Node_Link* startLink) { if (!startLink) { return RB_MIN(PeerRBTree, &parent->peerTree); } return PeerRBTree_RB_NEXT(startLink); } /** See: NodeStore.h */ struct NodeStore* NodeStore_new(struct Address* myAddress, struct Allocator* allocator, struct EventBase* eventBase, struct Log* logger, struct RumorMill* renumberMill) { struct Allocator* alloc = Allocator_child(allocator); struct NodeStore_pvt* out = Allocator_clone(alloc, (&(struct NodeStore_pvt) { .pub = { .nodeCapacity = NodeStore_DEFAULT_NODE_CAPACITY, .linkCapacity = NodeStore_DEFAULT_LINK_CAPACITY }, .renumberMill = renumberMill, .logger = logger, .eventBase = eventBase, .alloc = alloc })); Identity_set(out); // Create the self node struct Node_Two* selfNode = Allocator_calloc(alloc, sizeof(struct Node_Two), 1); Bits_memcpyConst(&selfNode->address, myAddress, sizeof(struct Address)); selfNode->encodingScheme = NumberCompress_defineScheme(alloc); selfNode->alloc = alloc; Identity_set(selfNode); out->pub.linkedNodes = 1; out->pub.selfNode = selfNode; struct Node_Link* selfLink = linkNodes(selfNode, selfNode, 1, 0xffffffffu, 0, 1, out); Node_setParentReachAndPath(selfNode, selfLink, UINT32_MAX, 1); selfNode->timeLastPinged = Time_currentTimeMilliseconds(out->eventBase); out->selfLink = selfLink; RB_INSERT(NodeRBTree, &out->nodeTree, selfNode); out->pub.selfAddress = &out->selfLink->child->address; return &out->pub; } ////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////// /** * Dump the table, one node at a time. */ struct Node_Two* NodeStore_dumpTable(struct NodeStore* nodeStore, uint32_t index) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); // TODO(cjd): Schlameil the painter uint32_t i = 0; struct Node_Two* nn = NULL; RB_FOREACH(nn, NodeRBTree, &store->nodeTree) { if (i++ == index) { return nn; } } return NULL; } struct Node_Two* NodeStore_getNextNode(struct NodeStore* nodeStore, struct Node_Two* lastNode) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); if (!lastNode) { return Identity_ncheck(RB_MIN(NodeRBTree, &store->nodeTree)); } return Identity_ncheck(NodeRBTree_RB_NEXT(lastNode)); } static struct Node_Two* getBestCycleB(struct Node_Two* node, uint8_t target[16], struct NodeStore_pvt* store) { uint32_t targetPfx = Address_prefixForIp6(target); uint32_t ourDistance = Address_getPrefix(store->pub.selfAddress) ^ targetPfx; struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &node->peerTree) { if (Node_getBestParent(next->child) != next || next == store->selfLink) { continue; } if (next->child->address.path == UINT64_MAX) { continue; } if ((Address_getPrefix(&next->child->address) ^ targetPfx) >= ourDistance) { continue; } return next->child; } return NULL; } static int getBestCycle(struct Node_Two* node, uint8_t target[16], struct Node_Two** output, int limit, int cycle, struct NodeStore_pvt* store) { Assert_true(cycle < 1000); if (cycle < limit) { int total = 0; struct Node_Link* next = NULL; RB_FOREACH_REVERSE(next, PeerRBTree, &node->peerTree) { if (*output) { return total; } if (Node_getBestParent(next->child) != next || next == store->selfLink) { continue; } total += getBestCycle(next->child, target, output, limit, cycle+1, store); } return total; } *output = getBestCycleB(node, target, store); return 1; } struct Node_Two* NodeStore_getBest(struct NodeStore* nodeStore, uint8_t targetAddress[16]) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); // First try to find the node directly struct Node_Two* n = NodeStore_nodeForAddr(nodeStore, targetAddress); if (n && Node_getBestParent(n)) { return n; } /** * The network is small enough that a per-bucket lookup is inefficient * Basically, the first bucket is likely to route through an "edge" node * In theory, it scales better if the network is large. // Next try to find the best node in the correct bucket struct Address fakeAddr; Bits_memcpyConst(fakeAddr.ip6.bytes, targetAddress, 16); uint16_t bucket = NodeStore_bucketForAddr(&store->pub.selfNode->address, &fakeAddr); struct Allocator* nodeListAlloc = Allocator_child(store->alloc); struct NodeList* nodeList = NodeStore_getNodesForBucket(&store->pub, nodeListAlloc, bucket, NodeStore_bucketSize); for (uint32_t i = 0 ; i < nodeList->size ; i++) { if (Node_getBestParent(nodeList->nodes[i])) { n = nodeList->nodes[i]; break; } } Allocator_free(nodeListAlloc); if (n && Node_getBestParent(n)) { return n; } */ // Finally try to find the best node that is a valid next hop (closer in keyspace) for (int i = 0; i < 10000; i++) { int ret = getBestCycle(store->pub.selfNode, targetAddress, &n, i, 0, store); if (n || !ret) { if (n) { Assert_true(Node_getBestParent(n)); } return n; } } // Apparently there are no valid next hops return NULL; } struct NodeList* NodeStore_getPeers(uint64_t label, const uint32_t max, struct Allocator* allocator, struct NodeStore* nodeStore) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); Log_debug(store->logger, "getPeers request for [%llx]", (unsigned long long) label); // truncate the label to the part which this node uses PLUS // the self-interface bit for the next hop if (label > 1) { int bitsUsed = NumberCompress_bitsUsedForLabel(label); label = (label & Bits_maxBits64(bitsUsed)) | 1 << bitsUsed; } struct NodeList* out = Allocator_calloc(allocator, sizeof(struct NodeList), 1); out->nodes = Allocator_calloc(allocator, sizeof(char*), max); struct Node_Link* next = NULL; RB_FOREACH(next, PeerRBTree, &store->pub.selfNode->peerTree) { uint64_t p = next->child->address.path; if (!LabelSplicer_isOneHop(p) && p != 1) { continue; } if (p < label) { continue; } int j; for (j = 0; j < (int)max; j++) { if (!out->nodes[j]) { continue; } if ((out->nodes[j]->address.path - label) > (p - label)) { continue; } break; } switch (j) { default: Bits_memmove(out->nodes, &out->nodes[1], (j - 1) * sizeof(char*)); case 1: out->nodes[j - 1] = next->child; case 0:; } } out->size = 0; for (int i = 0; i < (int)max; i++) { if (out->nodes[i]) { out->nodes = &out->nodes[i]; out->size = max - i; break; } } for (int i = 0; i < (int)out->size; i++) { Identity_check(out->nodes[i]); checkNode(out->nodes[i], store); Assert_true(out->nodes[i]->address.path); Assert_true(out->nodes[i]->address.path < (((uint64_t)1)<<63)); out->nodes[i] = Allocator_clone(allocator, out->nodes[i]); } return out; } static bool isOkAnswer(struct Node_Two* node, uint32_t compatVer, struct NodeStore_pvt* store) { if (node->address.path == UINT64_MAX) { // (very) unreachable return false; } if (!Version_isCompatible(compatVer, node->address.protocolVersion)) { return false; } if (node == store->pub.selfNode) { return false; } return true; } /** See: NodeStore.h */ struct NodeList* NodeStore_getClosestNodes(struct NodeStore* nodeStore, struct Address* targetAddress, const uint32_t count, uint32_t compatVer, struct Allocator* allocator) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct NodeList* out = Allocator_malloc(allocator, sizeof(struct NodeList)); out->nodes = Allocator_calloc(allocator, count, sizeof(char*)); out->size = count; struct Node_Two fakeNode = { .marked = 0 }; Bits_memcpyConst(&fakeNode.address, targetAddress, sizeof(struct Address)); struct Node_Two* next = Identity_ncheck(RB_NFIND(NodeRBTree, &store->nodeTree, &fakeNode)); if (!next) { out->size = 0; return out; } struct Node_Two* prev = Identity_ncheck(NodeRBTree_RB_PREV(next)); int idx = out->size-1; while (idx > -1) { if (prev && (!next || Address_closest(targetAddress, &next->address, &prev->address) > 0)) { if (isOkAnswer(prev, compatVer, store)) { out->nodes[idx--] = prev; } prev = Identity_ncheck(NodeRBTree_RB_PREV(prev)); continue; } if (next && (!prev || Address_closest(targetAddress, &next->address, &prev->address) < 0)) { if (isOkAnswer(next, compatVer, store)) { out->nodes[idx--] = next; } next = Identity_ncheck(NodeRBTree_RB_NEXT(next)); continue; } break; } out->nodes = &out->nodes[idx+1]; out->size -= idx+1; for (int i = 0; i < (int)out->size; i++) { Identity_check(out->nodes[i]); Assert_true(out->nodes[i]->address.path); Assert_true(out->nodes[i]->address.path < (((uint64_t)1)<<63)); out->nodes[i] = Allocator_clone(allocator, out->nodes[i]); } return out; } void NodeStore_disconnectedPeer(struct NodeStore* nodeStore, uint64_t path) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* nl = NodeStore_linkForPath(nodeStore, path); if (!nl) { return; } if (Defined(Log_DEBUG)) { uint8_t pathStr[20]; AddrTools_printPath(pathStr, path); Log_debug(store->logger, "NodeStore_disconnectedPeer(%s)", pathStr); } NodeStore_unlinkNodes(&store->pub, nl); } static void brokenLink(struct NodeStore_pvt* store, struct Node_Link* brokenLink) { NodeStore_unlinkNodes(&store->pub, brokenLink); } void NodeStore_brokenLink(struct NodeStore* nodeStore, uint64_t path, uint64_t pathAtErrorHop) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); if (Defined(Log_DEBUG)) { uint8_t pathStr[20]; uint8_t pathAtErrorHopStr[20]; AddrTools_printPath(pathStr, path); AddrTools_printPath(pathAtErrorHopStr, pathAtErrorHop); Log_debug(store->logger, "NodeStore_brokenLink(%s, %s)", pathStr, pathAtErrorHopStr); } struct Node_Link* link = store->selfLink; uint64_t thisPath = path; for (;;) { uint64_t nextPath = firstHopInPath(thisPath, &link, link, store); uint64_t mask = (((uint64_t)1) << (Bits_log2x64(thisPath) + 1)) - 1; if (Defined(Log_DEBUG)) { uint8_t maskStr[20]; uint8_t pathStr[20]; AddrTools_printPath(pathStr, nextPath); AddrTools_printPath(maskStr, mask); Log_debug(store->logger, "NodeStore_brokenLink() nextPath = [%s] mask = [%s]", pathStr, maskStr); } if ((pathAtErrorHop & mask) >= nextPath) { uint64_t cannPathAtErrorHop = EncodingScheme_convertLabel(link->child->encodingScheme, (pathAtErrorHop & mask), EncodingScheme_convertLabel_convertTo_CANNONICAL); uint8_t cannPathAtErrorHopStr[20]; AddrTools_printPath(cannPathAtErrorHopStr, cannPathAtErrorHop); Log_debug(store->logger, "NodeStore_brokenLink() converted pathAtErrorHop to [%s]", cannPathAtErrorHopStr); if (cannPathAtErrorHop != UINT64_MAX && (cannPathAtErrorHop & mask) == thisPath) { Log_debug(store->logger, "NodeStore_brokenLink() Great Success!"); brokenLink(store, link); return; } } else if (firstHopInPath_NO_NEXT_LINK == nextPath && thisPath == 1) { Log_debug(store->logger, "NodeStore_brokenLink() Great Success! (1link)"); Assert_ifParanoid(NodeStore_linkForPath(nodeStore, path) == link); brokenLink(store, link); return; } if (firstHopInPath_NO_NEXT_LINK == nextPath) { Log_debug(store->logger, "NodeStore_brokenLink() firstHopInPath_NO_NEXT_LINK"); // fails if pathAtErrorHop is garbage. Assert_ifTesting(!NodeStore_linkForPath(nodeStore, path)); return; } if (firstHopInPath_INVALID == nextPath) { Log_debug(store->logger, "NodeStore_brokenLink() firstHopInPath_INVALID"); return; } Assert_true(link); thisPath = nextPath; } } // When a response comes in, we need to pay attention to the path used. static void updatePathReach(struct NodeStore_pvt* store, const uint64_t path, uint32_t newReach) { struct Node_Link* link = store->selfLink; uint64_t pathFrag = path; uint64_t now = Time_currentTimeMilliseconds(store->eventBase); for (;;) { struct Node_Link* nextLink = NULL; uint64_t nextPath = firstHopInPath(pathFrag, &nextLink, link, store); if (firstHopInPath_ERR(nextPath)) { break; } // expecting behavior of nextLinkOnPath() Assert_ifParanoid(nextLink->parent == link->child); if (Node_getBestParent(nextLink->child) != nextLink) { // If nextLink->child->bestParent is worse than nextLink, we should replace it. uint64_t newPath = extendRoute(nextLink->parent->address.path, nextLink->parent->encodingScheme, nextLink->cannonicalLabel, link->inverseLinkEncodingFormNumber); if (newPath != extendRoute_INVALID && Node_getReach(nextLink->child) < newReach && Node_getReach(nextLink->parent) > newReach && Node_getReach(nextLink->child) < guessReachOfChild(nextLink)) { // This path apparently gives us a better route than our current bestParent. updateBestParent(nextLink, newReach, store); } } if (Node_getBestParent(nextLink->child) == nextLink) { // This is a performance hack, if nextLink->child->bestParent->parent is this node // we'll skip updating reach here since even if we did, it would be updated all over // again by the recursion inside of handleGoodNews because we're not deincrementing // newReach per hop. } else if (Node_getReach(link->child) >= newReach) { // Node already has enough reach... // selfNode reach == UINT32_MAX so this case handles it. } else if (!LabelSplicer_routesThrough(path, link->child->address.path)) { // The path the packet came in on is not actually the best known path to the node. } else { handleNews(link->child, newReach, store); } if (Node_getBestParent(link->child) == link) { // Update linkState. uint32_t guessedLinkState = subReach(Node_getReach(link->parent), newReach); uint32_t linkStateDiff = (guessedLinkState > link->linkState) ? (guessedLinkState - link->linkState) : 1; update(link, linkStateDiff, store); } else { // Well we at least know it's not dead. update(link, 1, store); } nextLink->timeLastSeen = now; pathFrag = nextPath; link = nextLink; } // Now we have to unconditionally update the reach for the last link in the chain. if (link->child && link->child->address.path == path) { // Behavior of nextLinkOnPath() Assert_ifParanoid(pathFrag == 1); handleNews(link->child, newReach, store); uint32_t newLinkState = subReach(Node_getReach(link->parent), newReach); update(link, newLinkState - link->linkState, store); } link->child->timeLastPinged = Time_currentTimeMilliseconds(store->eventBase); } void NodeStore_pathResponse(struct NodeStore* nodeStore, uint64_t path, uint64_t milliseconds) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* link = NodeStore_linkForPath(nodeStore, path); if (!link || link == store->selfLink) { return; } struct Node_Two* node = link->child; uint32_t newReach; if (node->address.path == path) { // Use old reach value to calculate new reach. newReach = calcNextReach(Node_getReach(node), milliseconds); } else { // Old reach value doesn't relate to this path, so we should do something different // FIXME(arceliar): calcNextReach is guessing what the reach would stabilize to // I think actually fixing this would require storing reach (or latency?) per link, // so we can calculate the expected reach for an arbitrary path newReach = calcNextReach(0, milliseconds); } updatePathReach(store, path, newReach); } void NodeStore_pathTimeout(struct NodeStore* nodeStore, uint64_t path) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); struct Node_Link* link = store->selfLink; uint64_t pathFrag = path; for (;;) { struct Node_Link* nextLink = NULL; uint64_t nextPath = firstHopInPath(pathFrag, &nextLink, link, store); if (firstHopInPath_ERR(nextPath)) { break; } // expecting behavior of nextLinkOnPath() Assert_true(nextLink->parent == link->child); if (link != store->selfLink) { // TODO(arceliar): Something sane. We don't know which link on the path is bad. // For now, just penalize them all. // The good ones will be rewarded again when they relay another ping. update(link, reachAfterTimeout(link->linkState)-link->linkState, store); } pathFrag = nextPath; link = nextLink; } link = NodeStore_linkForPath(nodeStore, path); if (!link || link->child->address.path != path) { return; } struct Node_Two* node = link->child; uint32_t newReach = reachAfterTimeout(Node_getReach(node)); if (!newReach) { // The node hasn't responded in a really long time. // Possible causes: // 1) The node is offline, and for some reason we're not getting an error packet back. // 2) The node is behind a node that's offline, and for some reason we're not getting error. // 3) The node is online, but in a bad state, where it cannot respond to pings. // (E.g. Our CA session broke and it refuses to reset, known bug in old versions.) // If we don't do something, we'll guessReachOfChild to re-discover a path through the link. // Doing that can get the node store stuck in a bad state where this node is blackholed. // As a workaround, break the link. That prevents re-discovering the same broken path. // If 2), we might accidentally break a valid link, but we should re-discover it the // next time we successfully contact link->child (via another path). brokenLink(store, link); return; } if (Defined(Log_DEBUG)) { uint8_t addr[60]; Address_print(addr, &node->address); Log_debug(store->logger, "Ping timeout for %s. changing reach from %u to %u\n", addr, Node_getReach(node), newReach); } handleNews(node, newReach, store); if (node->address.path != path) { return; } // TODO(cjd): What we really should be doing here is storing this link in a // potentially-down-list, after pinging the parent, if the parent does not respond // and then we replace the link with the parent's link and walk backwards up // the tree. If the parent does respond then we keep pinging the child of the path // hoping it will respond or die and as it's link-state is destroyed by subsequent // lost packets, children will be re-parented to other paths. // Keep checking until we're sure it's either OK or down. RumorMill_addNode(store->renumberMill, &node->address); if (link->parent != store->pub.selfNode) { // All we know for sure is that link->child didn't respond. // That could be because an earlier link is down. // Same idea as the workaround in NodeStore_brokenPath(); RumorMill_addNode(store->renumberMill, &link->parent->address); } } /* Find the address that describes the source's Nth (furthest-away) bucket. */ struct Address NodeStore_addrForBucket(struct Address* source, uint16_t bucket) { if (bucket >= NodeStore_bucketNumber) { // This does not exist. return *source; } else { struct Address addr = *source; // Figure out which bits of our address to flip for this step in keyspace. // Note: This assumes NodeStore_bucketNumber == 512 // (Some of those, the fc and every 16th bucket, won't actually have nodes) Assert_compileTime(NodeStore_bucketNumber == 512); uint64_t extras = 15 - ((bucket % 256)/16); uint64_t prefix = 0x0F - (bucket % 16); uint64_t bitmask = prefix << (4*extras); // We have the bitmask for this bucket, now we need to apply it. uint64_t* addrPart = (bucket < 256) ? &addr.ip6.longs.one_be : &addr.ip6.longs.two_be; *addrPart = Endian_bigEndianToHost64(*addrPart); *addrPart ^= bitmask; *addrPart = Endian_hostToBigEndian64(*addrPart); // Just to be sure... Assert_ifParanoid((bucket % 16) == 15 || NodeStore_bucketForAddr(source, &addr) == bucket); return addr; } } uint16_t NodeStore_bucketForAddr(struct Address* source, struct Address* dest) { uint16_t retVal = 0; // This is a place where the implementation depends on how buckets work. Assert_compileTime(NodeStore_bucketNumber == 512); uint64_t addrPart = source->ip6.longs.one_be ^ dest->ip6.longs.one_be; if (!addrPart) { // We're apparently close enough in keyspace to use two_be instead. addrPart = source->ip6.longs.two_be ^ dest->ip6.longs.two_be; retVal += 256; } addrPart = Endian_bigEndianToHost64(addrPart); uint64_t extras = Bits_log2x64(addrPart)/4; uint64_t prefix = addrPart >> (4*extras); retVal += (15 - extras)*16; retVal += 0x0F - prefix; return retVal; } uint64_t NodeStore_timeSinceLastPing(struct NodeStore* nodeStore, struct Node_Two* node) { struct NodeStore_pvt* store = Identity_check((struct NodeStore_pvt*)nodeStore); uint64_t now = Time_currentTimeMilliseconds(store->eventBase); uint64_t lastSeen = node->timeLastPinged; struct Node_Link* link = Node_getBestParent(node); while (link && link != store->selfLink) { lastSeen = (link->timeLastSeen < lastSeen) ? link->timeLastSeen : lastSeen; link = Node_getBestParent(link->parent); } return now - lastSeen; }