Exemple #1
0
// 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()
	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 {
					best_block = bl
				}
			}
		}
	} else {
		best_block = common.BlockChain.BlockIndex[hashstop.BIdx()]
	}
	last_block = common.BlockChain.BlockTreeEnd
	common.BlockChain.BlockIndexAccess.Unlock()

	var resp []byte
	var cnt uint32
	for cnt < 2000 {
		best_block = best_block.FindPathTo(last_block)
		if best_block == nil {
			break
		}
		resp = append(resp, append(best_block.BlockHeader[:], 0)...) // 81st byte is always zero
		cnt++
	}

	out := new(bytes.Buffer)
	btc.WriteVlen(out, uint64(cnt))
	out.Write(resp)
	c.SendRawMsg("headers", out.Bytes())
	return
}