don't deduplicate search responses, but limit the max number of nodes handled per response

This commit is contained in:
Arceliar 2020-02-08 17:04:00 -06:00
parent cd9613fddc
commit d7d0c2629c

View File

@ -25,6 +25,7 @@ import (
// This defines the time after which we time out a search (so it can restart).
const search_RETRY_TIME = 3 * time.Second
const search_STEP_TIME = 100 * time.Millisecond
const search_MAX_RES_SIZE = 16
// Information about an ongoing search.
// Includes the target NodeID, the bitmask to match it to an IP, and the list of nodes to visit / already visited.
@ -99,26 +100,22 @@ func (sinfo *searchInfo) handleDHTRes(res *dhtRes) {
// Adds the information from a dhtRes to an ongoing search.
// Info about a node that has already been visited is not re-added to the search.
func (sinfo *searchInfo) addToSearch(res *dhtRes) {
// Get a (deduplicated) list of known nodes to check
temp := make(map[crypto.NodeID]*dhtInfo, len(sinfo.toVisit)+len(res.Infos))
for _, info := range sinfo.toVisit {
temp[*info.getNodeID()] = info
// Used in sortng below
sortFunc := func(i, j int) bool {
// Should return true if i is closer to the destination than j
return dht_ordered(&sinfo.dest, sinfo.toVisit[i].getNodeID(), sinfo.toVisit[j].getNodeID())
}
// Add new results to the list
// Limit maximum number of results (mitigates DoS where nodes return a large number of bad results)
if len(res.Infos) > search_MAX_RES_SIZE {
sort.SliceStable(res.Infos, sortFunc)
res.Infos = res.Infos[:search_MAX_RES_SIZE]
}
// Append (without deduplication) to list of nodes to try
for _, info := range res.Infos {
temp[*info.getNodeID()] = info
}
// Move list to toVisit
delete(temp, sinfo.visited)
sinfo.toVisit = sinfo.toVisit[:0]
for _, info := range temp {
sinfo.toVisit = append(sinfo.toVisit, info)
}
// Sort
sort.SliceStable(sinfo.toVisit, func(i, j int) bool {
// Should return true if i is closer to the destination than j
return dht_ordered(&sinfo.dest, sinfo.toVisit[i].getNodeID(), sinfo.toVisit[j].getNodeID())
})
sort.SliceStable(sinfo.toVisit, sortFunc)
// Remove anything too far away to be useful
for idx, info := range sinfo.toVisit {
if !dht_ordered(&sinfo.dest, info.getNodeID(), &sinfo.visited) {
@ -147,6 +144,7 @@ func (sinfo *searchInfo) doSearchStep() {
sinfo.searches.router.dht.addCallback(&rq, sinfo.handleDHTRes)
sinfo.searches.router.dht.ping(next, &sinfo.dest)
sinfo.send++
sinfo.time = time.Now()
}
}
@ -190,7 +188,6 @@ func (sinfo *searchInfo) checkDHTRes(res *dhtRes) bool {
// Closer to the destination, so update visited
sinfo.searches.router.core.log.Debugln("Updating search:", &sinfo.dest, from.getNodeID(), sinfo.send, sinfo.recv)
sinfo.visited = *from.getNodeID()
sinfo.time = time.Now()
}
them := from.getNodeID()
var destMasked crypto.NodeID