commit inicial do projeto

internal/p2p/host.go

@@ -0,0 +1,66 @@
+package p2p
+
+import (
+	"crypto/rand"
+	"fmt"
+	"log"
+
+	"github.com/libp2p/go-libp2p"
+	crypto "github.com/libp2p/go-libp2p/core/crypto"
+	hostlib "github.com/libp2p/go-libp2p/core/host"
+	"github.com/libp2p/go-libp2p/core/network"
+	"github.com/libp2p/go-libp2p/core/peer"
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+// NewSecureHost cria um nó P2P com proteção básica anti-Sybil/DDoS
+func NewSecureHost(port int) (hostlib.Host, error) {
+	// Gera par de chaves (identidade)
+	priv, pub, err := crypto.GenerateKeyPairWithReader(crypto.Ed25519, 2048, rand.Reader)
+	if err != nil {
+		return nil, fmt.Errorf("falha ao gerar chave: %v", err)
+	}
+
+	pid, err := peer.IDFromPublicKey(pub)
+	if err != nil {
+		return nil, fmt.Errorf("erro ao obter PeerID: %v", err)
+	}
+
+	addr, _ := ma.NewMultiaddr(fmt.Sprintf("/ip4/0.0.0.0/tcp/%d", port))
+	h, err := libp2p.New(
+		libp2p.ListenAddrs(addr),
+		libp2p.Identity(priv),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("erro ao criar host libp2p: %v", err)
+	}
+
+	log.Printf("✅ Host P2P criado: %s (%s)\n", pid.String(), addr)
+
+	// Proteção: loga e valida conexões
+	h.Network().Notify(&connLogger{})
+
+	return h, nil
+}
+
+// connLogger registra e controla conexões suspeitas
+type connLogger struct{}
+
+func (c *connLogger) Connected(n network.Network, conn network.Conn) {
+	if err := LimitConnections(conn); err != nil {
+		log.Printf("🚫 Conexão rejeitada: %s (%v)", conn.RemotePeer(), err)
+		conn.Close()
+		return
+	}
+	log.Printf("🔗 Peer conectado: %s (%s)", conn.RemotePeer(), conn.RemoteMultiaddr())
+}
+
+func (c *connLogger) Disconnected(n network.Network, conn network.Conn) {
+	log.Printf("❌ Peer desconectado: %s", conn.RemotePeer())
+	ClearConnection(conn)
+}
+
+func (c *connLogger) OpenedStream(n network.Network, s network.Stream)      {}
+func (c *connLogger) ClosedStream(n network.Network, s network.Stream)      {}
+func (c *connLogger) Listen(n network.Network, addr ma.Multiaddr)           {}
+func (c *connLogger) ListenClose(n network.Network, addr ma.Multiaddr)      {}