p2p: add network simulation framework (#14982)

This commit introduces a network simulation framework which
can be used to run simulated networks of devp2p nodes. The
intention is to use this for testing protocols, performing
benchmarks and visualising emergent network behaviour.

1 files changed, 40 insertions, 0 deletions

diff --git a/p2p/discover/node.go b/p2p/discover/node.go
index d9cbd9448..fc928a91a 100644
--- a/p2p/discover/node.go
+++ b/p2p/discover/node.go
@@ -225,6 +225,11 @@ func (n *Node) UnmarshalText(text []byte) error {
 // The node identifier is a marshaled elliptic curve public key.
 type NodeID [NodeIDBits / 8]byte
 
+// Bytes returns a byte slice representation of the NodeID
+func (n NodeID) Bytes() []byte {
+	return n[:]
+}
+
 // NodeID prints as a long hexadecimal number.
 func (n NodeID) String() string {
 	return fmt.Sprintf("%x", n[:])
@@ -240,6 +245,41 @@ func (n NodeID) TerminalString() string {
 	return hex.EncodeToString(n[:8])
 }
 
+// MarshalText implements the encoding.TextMarshaler interface.
+func (n NodeID) MarshalText() ([]byte, error) {
+	return []byte(hex.EncodeToString(n[:])), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (n *NodeID) UnmarshalText(text []byte) error {
+	id, err := HexID(string(text))
+	if err != nil {
+		return err
+	}
+	*n = id
+	return nil
+}
+
+// BytesID converts a byte slice to a NodeID
+func BytesID(b []byte) (NodeID, error) {
+	var id NodeID
+	if len(b) != len(id) {
+		return id, fmt.Errorf("wrong length, want %d bytes", len(id))
+	}
+	copy(id[:], b)
+	return id, nil
+}
+
+// MustBytesID converts a byte slice to a NodeID.
+// It panics if the byte slice is not a valid NodeID.
+func MustBytesID(b []byte) NodeID {
+	id, err := BytesID(b)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
 // HexID converts a hex string to a NodeID.
 // The string may be prefixed with 0x.
 func HexID(in string) (NodeID, error) {