// rpcRelayBlock is an RPC that accepts a block from a peer.
// COMPATv0.5.1
func (cs *ConsensusSet) rpcRelayBlock(conn modules.PeerConn) error {
err := cs.tg.Add()
if err != nil {
return err
}
defer cs.tg.Done()
// Decode the block from the connection.
var b types.Block
err = encoding.ReadObject(conn, &b, types.BlockSizeLimit)
if err != nil {
return err
}
// Submit the block to the consensus set and broadcast it.
err = cs.managedAcceptBlock(b)
if err == errOrphan {
// If the block is an orphan, try to find the parents. The block
// received from the peer is discarded and will be downloaded again if
// the parent is found.
go func() {
err := cs.gateway.RPC(conn.RPCAddr(), "SendBlocks", cs.managedReceiveBlocks)
if err != nil {
cs.log.Debugln("WARN: failed to get parents of orphan block:", err)
}
}()
}
if err != nil {
return err
}
cs.managedBroadcastBlock(b)
return nil
}
// requestNodes is the calling end of the ShareNodes RPC.
func (g *Gateway) requestNodes(conn modules.PeerConn) error {
var nodes []modules.NetAddress
if err := encoding.ReadObject(conn, &nodes, maxSharedNodes*modules.MaxEncodedNetAddressLength); err != nil {
return err
}
g.mu.Lock()
for _, node := range nodes {
err := g.addNode(node)
if err != nil && err != errNodeExists && err != errOurAddress {
g.log.Printf("WARN: peer '%v' sent the invalid addr '%v'", conn.RPCAddr(), node)
}
}
g.save()
g.mu.Unlock()
return nil
}
// threadedHandleConn reads header data from a connection, then routes it to the
// appropriate handler for further processing.
func (g *Gateway) threadedHandleConn(conn modules.PeerConn) {
defer conn.Close()
if g.threads.Add() != nil {
return
}
defer g.threads.Done()
var id rpcID
if err := encoding.ReadObject(conn, &id, 8); err != nil {
return
}
// call registered handler for this ID
g.mu.RLock()
fn, ok := g.handlers[id]
g.mu.RUnlock()
if !ok {
g.log.Debugf("WARN: incoming conn %v requested unknown RPC \"%v\"", conn.RPCAddr(), id)
return
}
g.log.Debugf("INFO: incoming conn %v requested RPC \"%v\"", conn.RPCAddr(), id)
// call fn
err := fn(conn)
// don't log benign errors
if err == modules.ErrDuplicateTransactionSet || err == modules.ErrBlockKnown {
err = nil
}
if err != nil {
g.log.Debugf("WARN: incoming RPC \"%v\" from conn %v failed: %v", id, conn.RPCAddr(), err)
}
}
// requestNodes is the calling end of the ShareNodes RPC.
func (g *Gateway) requestNodes(conn modules.PeerConn) error {
conn.SetDeadline(time.Now().Add(connStdDeadline))
var nodes []modules.NetAddress
if err := encoding.ReadObject(conn, &nodes, maxSharedNodes*modules.MaxEncodedNetAddressLength); err != nil {
return err
}
g.mu.Lock()
for _, node := range nodes {
err := g.addNode(node)
if err != nil && err != errNodeExists && err != errOurAddress {
g.log.Printf("WARN: peer '%v' sent the invalid addr '%v'", conn.RPCAddr(), node)
}
}
err := g.save()
if err != nil {
g.log.Println("WARN: failed to save nodelist after requesting nodes:", err)
}
g.mu.Unlock()
return nil
}
// threadedRPCRelayHeader is an RPC that accepts a block header from a peer.
func (cs *ConsensusSet) threadedRPCRelayHeader(conn modules.PeerConn) error {
err := cs.tg.Add()
if err != nil {
return err
}
wg := new(sync.WaitGroup)
defer func() {
go func() {
wg.Wait()
cs.tg.Done()
}()
}()
// Decode the block header from the connection.
var h types.BlockHeader
err = encoding.ReadObject(conn, &h, types.BlockHeaderSize)
if err != nil {
return err
}
// Start verification inside of a bolt View tx.
cs.mu.RLock()
err = cs.db.View(func(tx *bolt.Tx) error {
// Do some relatively inexpensive checks to validate the header
return cs.validateHeader(boltTxWrapper{tx}, h)
})
cs.mu.RUnlock()
if err == errOrphan {
// If the header is an orphan, try to find the parents. Call needs to
// be made in a separate goroutine as execution requires calling an
// exported gateway method - threadedRPCRelayHeader was likely called
// from an exported gateway function.
//
// NOTE: In general this is bad design. Rather than recycling other
// calls, the whole protocol should have been kept in a single RPC.
// Because it is not, we have to do weird threading to prevent
// deadlocks, and we also have to be concerned every time the code in
// managedReceiveBlocks is adjusted.
wg.Add(1)
go func() {
err := cs.gateway.RPC(conn.RPCAddr(), "SendBlocks", cs.managedReceiveBlocks)
if err != nil {
cs.log.Debugln("WARN: failed to get parents of orphan header:", err)
}
wg.Done()
}()
return nil
} else if err != nil {
return err
}
// If the header is valid and extends the heaviest chain, fetch the
// corresponding block. Call needs to be made in a separate goroutine
// because an exported call to the gateway is used, which is a deadlock
// risk given that rpcRelayHeader is called from the gateway.
//
// NOTE: In general this is bad design. Rather than recycling other calls,
// the whole protocol should have been kept in a single RPC. Because it is
// not, we have to do weird threading to prevent deadlocks, and we also
// have to be concerned every time the code in managedReceiveBlock is
// adjusted.
wg.Add(1)
go func() {
err = cs.gateway.RPC(conn.RPCAddr(), "SendBlk", cs.managedReceiveBlock(h.ID()))
if err != nil {
cs.log.Debugln("WARN: failed to get header's corresponding block:", err)
}
wg.Done()
}()
return nil
}
