watchtower/wtdb/tower: store wt pk and addrs

watchtower/wtdb/tower.go

@@ -0,0 +1,65 @@
+package wtdb
+
+import (
+	"net"
+	"sync"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/lightningnetwork/lnd/lnwire"
+)
+
+// Tower holds the necessary components required to connect to a remote tower.
+// Communication is handled by brontide, and requires both a public key and an
+// address.
+type Tower struct {
+	// ID is a unique ID for this record assigned by the database.
+	ID uint64
+
+	// IdentityKey is the public key of the remote node, used to
+	// authenticate the brontide transport.
+	IdentityKey *btcec.PublicKey
+
+	// Addresses is a list of possible addresses to reach the tower.
+	Addresses []net.Addr
+
+	mu sync.RWMutex
+}
+
+// AddAddress adds the given address to the tower's in-memory list of addresses.
+// If the address's string is already present, the Tower will be left
+// unmodified. Otherwise, the adddress is prepended to the beginning of the
+// Tower's addresses, on the assumption that it is fresher than the others.
+func (t *Tower) AddAddress(addr net.Addr) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	// Ensure we don't add a duplicate address.
+	addrStr := addr.String()
+	for _, existingAddr := range t.Addresses {
+		if existingAddr.String() == addrStr {
+			return
+		}
+	}
+
+	// Add this address to the front of the list, on the assumption that it
+	// is a fresher address and will be tried first.
+	t.Addresses = append([]net.Addr{addr}, t.Addresses...)
+}
+
+// LNAddrs generates a list of lnwire.NetAddress from a Tower instance's
+// addresses. This can be used to have a client try multiple addresses for the
+// same Tower.
+func (t *Tower) LNAddrs() []*lnwire.NetAddress {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+
+	addrs := make([]*lnwire.NetAddress, 0, len(t.Addresses))
+	for _, addr := range t.Addresses {
+		addrs = append(addrs, &lnwire.NetAddress{
+			IdentityKey: t.IdentityKey,
+			Address:     addr,
+		})
+	}
+
+	return addrs
+}