swarm addr checks

net/swarm/addr.go

@@ -9,6 +9,75 @@ import (
 	manet "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr-net"
 )
 
+// SupportedTransportStrings is the list of supported transports for the swarm.
+// These are strings of encapsulated multiaddr protocols. E.g.:
+//   /ip4/tcp
+var SupportedTransportStrings = []string{
+	"/ip4/tcp",
+	"/ip6/tcp",
+	// "/ip4/udp/utp", disabled because the lib is broken
+	// "/ip6/udp/utp", disabled because the lib is broken
+	// "/ip4/udp/udt", disabled because the lib doesnt work on arm
+	// "/ip6/udp/udt", disabled because the lib doesnt work on arm
+}
+
+// SupportedTransportProtocols is the list of supported transports for the swarm.
+// These are []ma.Protocol lists. Populated at runtime from SupportedTransportStrings
+var SupportedTransportProtocols = [][]ma.Protocol{}
+
+func init() {
+	// initialize SupportedTransportProtocols
+	transports := make([][]ma.Protocol, len(SupportedTransportStrings))
+	for _, s := range SupportedTransportStrings {
+		t, err := ma.ProtocolsWithString(s)
+		if err != nil {
+			panic(err) // important to fix this in the codebase
+		}
+		transports = append(transports, t)
+	}
+	SupportedTransportProtocols = transports
+}
+
+// FilterAddrs is a filter that removes certain addresses
+// from a list. the addresses removed are those known NOT
+// to work with swarm. Namely, addresses with UTP.
+func FilterAddrs(a []ma.Multiaddr) []ma.Multiaddr {
+	b := make([]ma.Multiaddr, 0, len(a))
+	for _, addr := range a {
+		if AddrUsable(addr) {
+			b = append(b, addr)
+		}
+	}
+	return b
+}
+
+// AddrUsable returns whether the swarm can use this addr.
+func AddrUsable(a ma.Multiaddr) bool {
+	// test the address protocol list is in SupportedTransportProtocols
+
+	matches := func(a, b []ma.Protocol) bool {
+		if len(a) != len(b) {
+			return false
+		}
+
+		for i := range a {
+			if a[i].Code != b[i].Code {
+				return false
+			}
+		}
+		return true
+	}
+
+	transport := a.Protocols()
+	for _, supported := range SupportedTransportProtocols {
+		if matches(supported, transport) {
+			return true
+		}
+	}
+
+	return false
+}
+
 // ListenAddresses returns a list of addresses at which this swarm listens.
 func (s *Swarm) ListenAddresses() []ma.Multiaddr {
 	listeners := s.swarm.Listeners()

net/swarm/addr_test.go

@@ -0,0 +1,97 @@
+package swarm
+
+import (
+	"testing"
+
+	peer "github.com/jbenet/go-ipfs/p2p/peer"
+	testutil "github.com/jbenet/go-ipfs/util/testutil"
+
+	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
+	ma "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr"
+)
+
+func TestFilterAddrs(t *testing.T) {
+
+	m := func(s string) ma.Multiaddr {
+		maddr, err := ma.NewMultiaddr(s)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return maddr
+	}
+
+	bad := []ma.Multiaddr{
+		m("/ip4/1.2.3.4/udp/1234"),           // unreliable
+		m("/ip4/1.2.3.4/udp/1234/sctp/1234"), // not in manet
+		m("/ip4/1.2.3.4/udp/1234/utp"),       // utp is broken
+		m("/ip4/1.2.3.4/udp/1234/udt"),       // udt is broken on arm
+	}
+
+	good := []ma.Multiaddr{
+		m("/ip4/127.0.0.1/tcp/1234"),
+		m("/ip6/::1/tcp/1234"),
+	}
+
+	goodAndBad := append(good, bad...)
+
+	// test filters
+
+	for _, a := range bad {
+		if AddrUsable(a) {
+			t.Errorf("addr %s should be unusable", a)
+		}
+	}
+
+	for _, a := range good {
+		if !AddrUsable(a) {
+			t.Errorf("addr %s should be usable", a)
+		}
+	}
+
+	subtestAddrsEqual(t, FilterAddrs(bad), []ma.Multiaddr{})
+	subtestAddrsEqual(t, FilterAddrs(good), good)
+	subtestAddrsEqual(t, FilterAddrs(goodAndBad), good)
+
+	// now test it with swarm
+
+	id, err := testutil.RandPeerID()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ps := peer.NewPeerstore()
+	ctx := context.Background()
+
+	if _, err := NewNetwork(ctx, bad, id, ps); err == nil {
+		t.Fatal("should have failed to create swarm")
+	}
+
+	if _, err := NewNetwork(ctx, good, id, ps); err != nil {
+		t.Fatal("should have succeeded in creating swarm", err)
+	}
+
+	if _, err := NewNetwork(ctx, goodAndBad, id, ps); err == nil {
+		t.Fatal("should have failed to create swarm")
+	}
+}
+
+func subtestAddrsEqual(t *testing.T, a, b []ma.Multiaddr) {
+	if len(a) != len(b) {
+		t.Error(t)
+	}
+
+	in := func(addr ma.Multiaddr, l []ma.Multiaddr) bool {
+		for _, addr2 := range l {
+			if addr.Equal(addr2) {
+				return true
+			}
+		}
+		return false
+	}
+
+	for _, aa := range a {
+		if !in(aa, b) {
+			t.Errorf("%s not in %s", aa, b)
+		}
+	}
+}

net/swarm/swarm_listen.go

@@ -1,6 +1,8 @@
 package swarm
 
 import (
+	"fmt"
+
 	conn "github.com/jbenet/go-ipfs/p2p/net/conn"
 	lgbl "github.com/jbenet/go-ipfs/util/eventlog/loggables"
 
@@ -12,6 +14,13 @@ import (
 
 // Open listeners for each network the swarm should listen on
 func (s *Swarm) listen(addrs []ma.Multiaddr) error {
+
+	for _, addr := range addrs {
+		if !AddrUsable(addr) {
+			return fmt.Errorf("cannot use addr: %s", addr)
+		}
+	}
+
 	retErr := multierr.New()
 
 	// listen on every address

test/util/util.go

@@ -36,3 +36,5 @@ func GenHostSwarm(t *testing.T, ctx context.Context) *bhost.BasicHost {
 	n := GenSwarmNetwork(t, ctx)
 	return bhost.New(n)
 }
+
+var RandPeerID = tu.RandPeerID