Enable more hostinet socket tests.

Fixes:
* Support for SO_MULTICAST_IF socket option.
* Support IPPROTO_ICMP protocol.

The tests that require raw sockets are disabled on hostinet, since those are
not yet supported.

PiperOrigin-RevId: 509563771

pkg/abi/linux/socket.go

@@ -239,6 +239,9 @@ const SockAddrMax = 128
 // +marshal
 type InetAddr [4]byte
 
+// SizeOfInetAddr is the size of InetAddr.
+var SizeOfInetAddr = uint32((*InetAddr)(nil).SizeBytes())
+
 // SockAddrInet is struct sockaddr_in, from uapi/linux/in.h.
 //
 // +marshal

pkg/sentry/socket/hostinet/socket.go

@@ -193,6 +193,8 @@ func (p *socketProvider) Socket(t *kernel.Task, stypeflags linux.SockType, proto
 			// IPPROTO_IP with SOCK_DGRAM causes proto to actually
 			// be IPPROTO_UDP.
 			protocol = unix.IPPROTO_UDP
+		case unix.IPPROTO_ICMP:
+			// ok
 		case unix.IPPROTO_UDP:
 			// ok
 		default:

pkg/sentry/socket/hostinet/sockopt.go

@@ -59,6 +59,7 @@ type SockOpt struct {
 var SockOpts = []SockOpt{
 	{linux.SOL_IP, linux.IP_ADD_MEMBERSHIP, 0, false, true},
 	{linux.SOL_IP, linux.IP_DROP_MEMBERSHIP, 0, false, true},
+	{linux.SOL_IP, linux.IP_MULTICAST_IF, uint64(linux.SizeOfInetAddr), true, true},
 	{linux.SOL_IP, linux.IP_MULTICAST_LOOP, 0 /* can be 32-bit int or 8-bit uint */, true, true},
 	{linux.SOL_IP, linux.IP_MULTICAST_TTL, 0 /* can be 32-bit int or 8-bit uint */, true, true},
 	{linux.SOL_IP, linux.IP_PKTINFO, sizeofInt32, true, true},

test/syscalls/BUILD

@@ -730,6 +730,7 @@ syscall_test(
 )
 
 syscall_test(
+    add_hostinet = True,
     test = "//test/syscalls/linux:socket_ipv4_udp_unbound_external_networking_test",
 )
 
@@ -775,6 +776,7 @@ syscall_test(
 
 syscall_test(
     size = "medium",
+    add_hostinet = True,
     test = "//test/syscalls/linux:socket_ipv4_datagram_based_socket_unbound_loopback_test",
 )
 

test/syscalls/linux/socket_ipv4_datagram_based_socket_unbound.cc

@@ -24,6 +24,9 @@ namespace testing {
 void IPv4DatagramBasedUnboundSocketTest::SetUp() {
   if (GetParam().type & SOCK_RAW) {
     SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));
+
+    // TODO(b/267210840): Support raw sockets on hostinet.
+    SKIP_IF(IsRunningWithHostinet());
   }
 }