// Handle getheaders protocol command
// https://en.bitcoin.it/wiki/Protocol_specification#getheaders
func (c *OneConnection) GetHeaders(pl []byte) {
h2get, hashstop, e := parseLocatorsPayload(pl)
if e != nil || hashstop == nil {
println("GetHeaders: error parsing payload from", c.PeerAddr.Ip())
c.DoS("BadGetHdrs")
return
}
if common.DebugLevel > 1 {
println("GetHeaders", len(h2get), hashstop.String())
}
var best_block, last_block *chain.BlockTreeNode
common.BlockChain.BlockIndexAccess.Lock()
//println("GetHeaders", len(h2get), hashstop.String())
if len(h2get) > 0 {
for i := range h2get {
if bl, ok := common.BlockChain.BlockIndex[h2get[i].BIdx()]; ok {
if best_block == nil || bl.Height > best_block.Height {
//println(" ... bbl", i, bl.Height, bl.BlockHash.String())
best_block = bl
}
}
}
} else {
best_block = common.BlockChain.BlockIndex[hashstop.BIdx()]
}
if best_block == nil {
println("GetHeaders: best_block not found")
common.BlockChain.BlockIndexAccess.Unlock()
common.CountSafe("GetHeadersBadBlock")
return
}
last_block = common.BlockChain.BlockTreeEnd
var resp []byte
var cnt uint32
defer func() {
common.BlockChain.BlockIndexAccess.Unlock()
// If we get a hash of an old orphaned blocks, FindPathTo() will panic, so...
if r := recover(); r != nil {
common.CountSafe("GetHeadersOrphBlk")
err, ok := r.(error)
if !ok {
err = fmt.Errorf("pkg: %v", r)
}
fmt.Println("GetHeaders panic recovered:", err.Error())
fmt.Println("Cnt:", cnt, " len(h2get):", len(h2get))
if best_block != nil {
fmt.Println("BestBlock:", best_block.Height, best_block.BlockHash.String())
}
if last_block != nil {
fmt.Println("LastBlock:", last_block.Height, last_block.BlockHash.String())
}
}
// send the response
out := new(bytes.Buffer)
btc.WriteVlen(out, uint64(cnt))
out.Write(resp)
c.SendRawMsg("headers", out.Bytes())
}()
for cnt < 2000 {
best_block = best_block.FindPathTo(last_block)
if best_block == nil {
//println("FindPathTo failed", last_block.BlockHash.String(), cnt)
//println("resp:", hex.EncodeToString(resp))
break
}
resp = append(resp, append(best_block.BlockHeader[:], 0)...) // 81st byte is always zero
cnt++
}
// Note: the deferred function will be called before exiting
return
}
