Receive broadcast packets on interested endpoints

When a broadcast packet is received by the stack, the packet should be
delivered to each endpoint that may be interested in the packet. This
includes all any address and specified broadcast address listeners.

Test: integration_test.TestReuseAddrAndBroadcast
PiperOrigin-RevId: 332060652

2 files changed, 62 insertions, 38 deletions

diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index 0d13e1efd..b1e5f1b24 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -5214,6 +5214,8 @@ func TestListenBacklogFull(t *testing.T) {
 func TestListenNoAcceptNonUnicastV4(t *testing.T) {
 	multicastAddr := tcpip.Address("\xe0\x00\x01\x02")
 	otherMulticastAddr := tcpip.Address("\xe0\x00\x01\x03")
+	subnet := context.StackAddrWithPrefix.Subnet()
+	subnetBroadcastAddr := subnet.Broadcast()
 
 	tests := []struct {
 		name    string
@@ -5221,53 +5223,59 @@ func TestListenNoAcceptNonUnicastV4(t *testing.T) {
 		dstAddr tcpip.Address
 	}{
 		{
-			"SourceUnspecified",
-			header.IPv4Any,
-			context.StackAddr,
+			name:    "SourceUnspecified",
+			srcAddr: header.IPv4Any,
+			dstAddr: context.StackAddr,
 		},
 		{
-			"SourceBroadcast",
-			header.IPv4Broadcast,
-			context.StackAddr,
+			name:    "SourceBroadcast",
+			srcAddr: header.IPv4Broadcast,
+			dstAddr: context.StackAddr,
 		},
 		{
-			"SourceOurMulticast",
-			multicastAddr,
-			context.StackAddr,
+			name:    "SourceOurMulticast",
+			srcAddr: multicastAddr,
+			dstAddr: context.StackAddr,
 		},
 		{
-			"SourceOtherMulticast",
-			otherMulticastAddr,
-			context.StackAddr,
+			name:    "SourceOtherMulticast",
+			srcAddr: otherMulticastAddr,
+			dstAddr: context.StackAddr,
 		},
 		{
-			"DestUnspecified",
-			context.TestAddr,
-			header.IPv4Any,
+			name:    "DestUnspecified",
+			srcAddr: context.TestAddr,
+			dstAddr: header.IPv4Any,
 		},
 		{
-			"DestBroadcast",
-			context.TestAddr,
-			header.IPv4Broadcast,
+			name:    "DestBroadcast",
+			srcAddr: context.TestAddr,
+			dstAddr: header.IPv4Broadcast,
 		},
 		{
-			"DestOurMulticast",
-			context.TestAddr,
-			multicastAddr,
+			name:    "DestOurMulticast",
+			srcAddr: context.TestAddr,
+			dstAddr: multicastAddr,
 		},
 		{
-			"DestOtherMulticast",
-			context.TestAddr,
-			otherMulticastAddr,
+			name:    "DestOtherMulticast",
+			srcAddr: context.TestAddr,
+			dstAddr: otherMulticastAddr,
+		},
+		{
+			name:    "SrcSubnetBroadcast",
+			srcAddr: subnetBroadcastAddr,
+			dstAddr: context.StackAddr,
+		},
+		{
+			name:    "DestSubnetBroadcast",
+			srcAddr: context.TestAddr,
+			dstAddr: subnetBroadcastAddr,
 		},
 	}
 
 	for _, test := range tests {
-		test := test // capture range variable
-
 		t.Run(test.name, func(t *testing.T) {
-			t.Parallel()
-
 			c := context.New(t, defaultMTU)
 			defer c.Cleanup()
 
@@ -5367,11 +5375,7 @@ func TestListenNoAcceptNonUnicastV6(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		test := test // capture range variable
-
 		t.Run(test.name, func(t *testing.T) {
-			t.Parallel()
-
 			c := context.New(t, defaultMTU)
 			defer c.Cleanup()
 
diff --git a/pkg/tcpip/transport/tcp/testing/context/context.go b/pkg/tcpip/transport/tcp/testing/context/context.go
index baf7df197..85e8c1c75 100644
--- a/pkg/tcpip/transport/tcp/testing/context/context.go
+++ b/pkg/tcpip/transport/tcp/testing/context/context.go
@@ -53,11 +53,11 @@ const (
 	TestPort = 4096
 
 	// StackV6Addr is the IPv6 address assigned to the stack.
-	StackV6Addr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
+	StackV6Addr = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
 
 	// TestV6Addr is the source address for packets sent to the stack via
 	// the link layer endpoint.
-	TestV6Addr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02"
+	TestV6Addr = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02"
 
 	// StackV4MappedAddr is StackAddr as a mapped v6 address.
 	StackV4MappedAddr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff" + StackAddr
@@ -73,6 +73,18 @@ const (
 	testInitialSequenceNumber = 789
 )
 
+// StackAddrWithPrefix is StackAddr with its associated prefix length.
+var StackAddrWithPrefix = tcpip.AddressWithPrefix{
+	Address:   StackAddr,
+	PrefixLen: 24,
+}
+
+// StackV6AddrWithPrefix is StackV6Addr with its associated prefix length.
+var StackV6AddrWithPrefix = tcpip.AddressWithPrefix{
+	Address:   StackV6Addr,
+	PrefixLen: header.IIDOffsetInIPv6Address * 8,
+}
+
 // Headers is used to represent the TCP header fields when building a
 // new packet.
 type Headers struct {
@@ -184,12 +196,20 @@ func New(t *testing.T, mtu uint32) *Context {
 		t.Fatalf("CreateNICWithOptions(_, _, %+v) failed: %v", opts2, err)
 	}
 
-	if err := s.AddAddress(1, ipv4.ProtocolNumber, StackAddr); err != nil {
-		t.Fatalf("AddAddress failed: %v", err)
+	v4ProtocolAddr := tcpip.ProtocolAddress{
+		Protocol:          ipv4.ProtocolNumber,
+		AddressWithPrefix: StackAddrWithPrefix,
+	}
+	if err := s.AddProtocolAddress(1, v4ProtocolAddr); err != nil {
+		t.Fatalf("AddProtocolAddress(1, %#v): %s", v4ProtocolAddr, err)
 	}
 
-	if err := s.AddAddress(1, ipv6.ProtocolNumber, StackV6Addr); err != nil {
-		t.Fatalf("AddAddress failed: %v", err)
+	v6ProtocolAddr := tcpip.ProtocolAddress{
+		Protocol:          ipv6.ProtocolNumber,
+		AddressWithPrefix: StackV6AddrWithPrefix,
+	}
+	if err := s.AddProtocolAddress(1, v6ProtocolAddr); err != nil {
+		t.Fatalf("AddProtocolAddress(1, %#v): %s", v6ProtocolAddr, err)
 	}
 
 	s.SetRouteTable([]tcpip.Route{