// verifySettings reads a signed HostSettings object from conn, validates the
// signature, and checks for discrepancies between the known settings and the
// received settings. If there is a discrepancy, the hostDB is notified. The
// received settings are returned.
func verifySettings(conn net.Conn, host modules.HostDBEntry) (modules.HostDBEntry, error) {
// convert host key (types.SiaPublicKey) to a crypto.PublicKey
if host.PublicKey.Algorithm != types.SignatureEd25519 || len(host.PublicKey.Key) != crypto.PublicKeySize {
build.Critical("hostdb did not filter out host with wrong signature algorithm:", host.PublicKey.Algorithm)
return modules.HostDBEntry{}, errors.New("host used unsupported signature algorithm")
}
var pk crypto.PublicKey
copy(pk[:], host.PublicKey.Key)
// read signed host settings
var recvSettings modules.HostExternalSettings
if err := crypto.ReadSignedObject(conn, &recvSettings, modules.NegotiateMaxHostExternalSettingsLen, pk); err != nil {
return modules.HostDBEntry{}, errors.New("couldn't read host's settings: " + err.Error())
}
// TODO: check recvSettings against host.HostExternalSettings. If there is
// a discrepancy, write the error to conn.
if recvSettings.NetAddress != host.NetAddress {
// for now, just overwrite the NetAddress, since we know that
// host.NetAddress works (it was the one we dialed to get conn)
recvSettings.NetAddress = host.NetAddress
}
host.HostExternalSettings = recvSettings
return host, nil
}
// managedUpdateEntry updates an entry in the hostdb after a scan has taken
// place.
func (hdb *HostDB) managedUpdateEntry(entry *hostEntry, newSettings modules.HostExternalSettings, netErr error) {
hdb.mu.Lock()
defer hdb.mu.Unlock()
// Regardless of whether the host responded, add it to allHosts.
priorHost, exists := hdb.allHosts[entry.NetAddress]
if !exists {
hdb.allHosts[entry.NetAddress] = entry
}
// If the scan was unsuccessful, decrement the host's reliability.
if netErr != nil {
if exists && bytes.Equal(priorHost.PublicKey.Key, entry.PublicKey.Key) {
// Only decrement the reliability if the public key in the
// hostdb matches the public key in the host announcement -
// the failure may just be a failed signature, indicating
// the wrong public key.
hdb.decrementReliability(entry.NetAddress, UnreachablePenalty)
}
return
}
// The host entry should be updated to reflect the new weight. The safety
// properties of the tree require that the weight does not change while the
// node is in the tree, so the node must be removed before the settings and
// weight are changed.
existingNode, exists := hdb.activeHosts[entry.NetAddress]
if exists {
existingNode.removeNode()
delete(hdb.activeHosts, entry.NetAddress)
}
// Update the host settings, reliability, and weight. The old NetAddress
// must be preserved.
newSettings.NetAddress = entry.HostExternalSettings.NetAddress
entry.HostExternalSettings = newSettings
entry.Reliability = MaxReliability
entry.Weight = calculateHostWeight(*entry)
entry.Online = true
// If 'maxActiveHosts' has not been reached, add the host to the
// activeHosts tree.
if _, exists := hdb.activeHosts[entry.NetAddress]; exists || len(hdb.activeHosts) < maxActiveHosts {
hdb.insertNode(entry)
}
hdb.save()
}