[cmd] support SendTx to other chains via IBC

cmd/commands/relay.go

@@ -90,6 +90,11 @@ OUTER:
 			logger.Error("Error parsing sequence number from query", "query.Value", query.Value, "error", err.Error())
 			continue OUTER
 		}
+		seq -= 1 // seq is the packet count. -1 because 0-indexed
+
+		if nextSeq <= int(seq) {
+			logger.Info("Got new packets", "last-sequence", nextSeq-1, "new-sequence", seq)
+		}
 
 		// get all packets since the last one we relayed
 		for ; nextSeq <= int(seq); nextSeq++ {

cmd/commands/tx.go

@@ -3,6 +3,7 @@ package commands
 import (
 	"encoding/hex"
 	"fmt"
+	"strings"
 
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -81,12 +82,29 @@ func init() {
 
 func sendTxCmd(cmd *cobra.Command, args []string) error {
 
+	var toHex string
+	var chainPrefix string
+	spl := strings.Split(toFlag, "/")
+	switch len(spl) {
+	case 1:
+		toHex = spl[0]
+	case 2:
+		chainPrefix = spl[0]
+		toHex = spl[1]
+	default:
+		return errors.Errorf("To address has too many slashes")
+	}
+
 	// convert destination address to bytes
-	to, err := hex.DecodeString(StripHex(toFlag))
+	to, err := hex.DecodeString(StripHex(toHex))
 	if err != nil {
 		return errors.Errorf("To address is invalid hex: %v\n", err)
 	}
 
+	if chainPrefix != "" {
+		to = []byte(chainPrefix + "/" + string(to))
+	}
+
 	// load the priv key
 	privKey, err := LoadKey(fromFlag)
 	if err != nil {

plugins/ibc/ibc.go

@@ -69,7 +69,9 @@ func NewPacket(src, dst string, seq uint64, payload Payload) Packet {
 	}
 }
 
-// GetSequenceNumber gets the sequence number for packets being sent from the src chain to the dst chain
+// GetSequenceNumber gets the sequence number for packets being sent from the src chain to the dst chain.
+// The sequence number counts how many packets have been sent.
+// The next packet must include the latest sequence number.
 func GetSequenceNumber(store types.KVStore, src, dst string) uint64 {
 	sequenceKey := toKey(_IBC, _EGRESS, src, dst)
 	seqBytes := store.Get(sequenceKey)