Add multicast support

PiperOrigin-RevId: 212750821
Change-Id: I822fd63e48c684b45fd91f9ce057867b7eceb792

4 files changed, 117 insertions, 8 deletions

diff --git a/pkg/tcpip/network/ipv4/BUILD b/pkg/tcpip/network/ipv4/BUILD
index 19314e9bd..90d65d531 100644
--- a/pkg/tcpip/network/ipv4/BUILD
+++ b/pkg/tcpip/network/ipv4/BUILD
@@ -1,6 +1,6 @@
 package(licenses = ["notice"])  # Apache 2.0
 
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
 
 go_library(
     name = "ipv4",
@@ -21,3 +21,19 @@ go_library(
         "//pkg/tcpip/stack",
     ],
 )
+
+go_test(
+    name = "ipv4_test",
+    size = "small",
+    srcs = ["ipv4_test.go"],
+    deps = [
+        "//pkg/tcpip",
+        "//pkg/tcpip/header",
+        "//pkg/tcpip/link/channel",
+        "//pkg/tcpip/link/sniffer",
+        "//pkg/tcpip/network/ipv4",
+        "//pkg/tcpip/stack",
+        "//pkg/tcpip/transport/udp",
+        "//pkg/waiter",
+    ],
+)
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index de21e623e..74454f605 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -121,5 +121,5 @@ func sendPing4(r *stack.Route, code byte, data buffer.View) *tcpip.Error {
 	icmpv4.SetChecksum(^header.Checksum(icmpv4, header.Checksum(data, 0)))
 
 	vv := buffer.NewVectorisedView(len(data), []buffer.View{data})
-	return r.WritePacket(&hdr, vv, header.ICMPv4ProtocolNumber)
+	return r.WritePacket(&hdr, vv, header.ICMPv4ProtocolNumber, r.DefaultTTL())
 }
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index 478957827..0a2378a6a 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -44,10 +44,6 @@ const (
 
 	// buckets is the number of identifier buckets.
 	buckets = 2048
-
-	// defaultIPv4TTL is the defautl TTL for IPv4 Packets egressed by
-	// Netstack.
-	defaultIPv4TTL = 255
 )
 
 type address [header.IPv4AddressSize]byte
@@ -78,6 +74,11 @@ func newEndpoint(nicid tcpip.NICID, addr tcpip.Address, dispatcher stack.Transpo
 	return e
 }
 
+// DefaultTTL is the default time-to-live value for this endpoint.
+func (e *endpoint) DefaultTTL() uint8 {
+	return 255
+}
+
 // MTU implements stack.NetworkEndpoint.MTU. It returns the link-layer MTU minus
 // the network layer max header length.
 func (e *endpoint) MTU() uint32 {
@@ -106,7 +107,7 @@ func (e *endpoint) MaxHeaderLength() uint16 {
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, hdr *buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, hdr *buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8) *tcpip.Error {
 	ip := header.IPv4(hdr.Prepend(header.IPv4MinimumSize))
 	length := uint16(hdr.UsedLength() + payload.Size())
 	id := uint32(0)
@@ -119,7 +120,7 @@ func (e *endpoint) WritePacket(r *stack.Route, hdr *buffer.Prependable, payload
 		IHL:         header.IPv4MinimumSize,
 		TotalLength: length,
 		ID:          uint16(id),
-		TTL:         defaultIPv4TTL,
+		TTL:         ttl,
 		Protocol:    uint8(protocol),
 		SrcAddr:     tcpip.Address(e.address[:]),
 		DstAddr:     r.RemoteAddress,
diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go
new file mode 100644
index 000000000..2b7067a50
--- /dev/null
+++ b/pkg/tcpip/network/ipv4/ipv4_test.go
@@ -0,0 +1,92 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ipv4_test
+
+import (
+	"testing"
+
+	"gvisor.googlesource.com/gvisor/pkg/tcpip"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/header"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/link/channel"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/link/sniffer"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/transport/udp"
+	"gvisor.googlesource.com/gvisor/pkg/waiter"
+)
+
+func TestExcludeBroadcast(t *testing.T) {
+	s := stack.New([]string{ipv4.ProtocolName}, []string{udp.ProtocolName}, stack.Options{})
+
+	const defaultMTU = 65536
+	id, _ := channel.New(256, defaultMTU, "")
+	if testing.Verbose() {
+		id = sniffer.New(id)
+	}
+	if err := s.CreateNIC(1, id); err != nil {
+		t.Fatalf("CreateNIC failed: %v", err)
+	}
+
+	if err := s.AddAddress(1, ipv4.ProtocolNumber, header.IPv4Broadcast); err != nil {
+		t.Fatalf("AddAddress failed: %v", err)
+	}
+	if err := s.AddAddress(1, ipv4.ProtocolNumber, header.IPv4Any); err != nil {
+		t.Fatalf("AddAddress failed: %v", err)
+	}
+
+	s.SetRouteTable([]tcpip.Route{{
+		Destination: "\x00\x00\x00\x00",
+		Mask:        "\x00\x00\x00\x00",
+		Gateway:     "",
+		NIC:         1,
+	}})
+
+	randomAddr := tcpip.FullAddress{NIC: 1, Addr: "\x0a\x00\x00\x01", Port: 53}
+
+	var wq waiter.Queue
+	t.Run("WithoutPrimaryAddress", func(t *testing.T) {
+		ep, err := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer ep.Close()
+
+		// Cannot connect using a broadcast address as the source.
+		if err := ep.Connect(randomAddr); err != tcpip.ErrNoRoute {
+			t.Errorf("got ep.Connect(...) = %v, want = %v", err, tcpip.ErrNoRoute)
+		}
+
+		// However, we can bind to a broadcast address to listen.
+		if err := ep.Bind(tcpip.FullAddress{Addr: header.IPv4Broadcast, Port: 53, NIC: 1}, nil); err != nil {
+			t.Errorf("Bind failed: %v", err)
+		}
+	})
+
+	t.Run("WithPrimaryAddress", func(t *testing.T) {
+		ep, err := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer ep.Close()
+
+		// Add a valid primary endpoint address, now we can connect.
+		if err := s.AddAddress(1, ipv4.ProtocolNumber, "\x0a\x00\x00\x02"); err != nil {
+			t.Fatalf("AddAddress failed: %v", err)
+		}
+		if err := ep.Connect(randomAddr); err != nil {
+			t.Errorf("Connect failed: %v", err)
+		}
+	})
+}