[netstack] Add SOL_IP and SOL_IPV6 options to SocketOptions.

We will use SocketOptions for all kinds of options, not just SOL_SOCKET options
because (1) it is consistent with Linux which defines all option variables on
the top level socket struct, (2) avoid code complexity. Appropriate checks
have been added for matching option level to the endpoint type.

Ported the following options to this new utility:
- IP_MULTICAST_LOOP
- IP_RECVTOS
- IPV6_RECVTCLASS
- IP_PKTINFO
- IP_HDRINCL
- IPV6_V6ONLY

Changes in behavior (these are consistent with what Linux does AFAICT):
- Now IP_MULTICAST_LOOP can be set for TCP (earlier it was a noop) but does not
  affect the endpoint itself.
- We can now getsockopt IP_HDRINCL (earlier we would get an error).
- Now we return ErrUnknownProtocolOption if SOL_IP or SOL_IPV6 options are used
  on unix sockets.
- Now we return ErrUnknownProtocolOption if SOL_IPV6 options are used on non
  AF_INET6 endpoints.

This change additionally makes the following modifications:
- Add State() uint32 to commonEndpoint because both tcpip.Endpoint and
  transport.Endpoint interfaces have it. It proves to be quite useful.
- Gets rid of SocketOptionsHandler.IsListening(). It was an anomaly as it was
  not a handler. It is now implemented on netstack itself.
- Gets rid of tcp.endpoint.EndpointInfo and directly embeds
  stack.TransportEndpointInfo. There was an unnecessary level of embedding
  which served no purpose.
- Removes some checks dual_stack_test.go that used the errors from
  GetSockOptBool(tcpip.V6OnlyOption) to confirm some state. This is not
  consistent with the new design and also seemed to be testing the
  implementation instead of behavior.

PiperOrigin-RevId: 344354051

1 files changed, 89 insertions, 17 deletions

diff --git a/pkg/tcpip/socketops.go b/pkg/tcpip/socketops.go
index 1b1188ee5..cced4d8fc 100644
--- a/pkg/tcpip/socketops.go
+++ b/pkg/tcpip/socketops.go
@@ -19,10 +19,8 @@ import (
 )
 
 // SocketOptionsHandler holds methods that help define endpoint specific
-// behavior for socket options.
-// These must be implemented by endpoints to:
-// - Get notified when socket level options are set.
-// - Provide endpoint specific socket options.
+// behavior for socket level socket options. These must be implemented by
+// endpoints to get notified when socket level options are set.
 type SocketOptionsHandler interface {
 	// OnReuseAddressSet is invoked when SO_REUSEADDR is set for an endpoint.
 	OnReuseAddressSet(v bool)
@@ -32,10 +30,6 @@ type SocketOptionsHandler interface {
 
 	// OnKeepAliveSet is invoked when SO_KEEPALIVE is set for an endpoint.
 	OnKeepAliveSet(v bool)
-
-	// IsListening is invoked to fetch SO_ACCEPTCONN option value for an
-	// endpoint. It is used to indicate if the socket is a listening socket.
-	IsListening() bool
 }
 
 // DefaultSocketOptionsHandler is an embeddable type that implements no-op
@@ -53,11 +47,8 @@ func (*DefaultSocketOptionsHandler) OnReusePortSet(bool) {}
 // OnKeepAliveSet implements SocketOptionsHandler.OnKeepAliveSet.
 func (*DefaultSocketOptionsHandler) OnKeepAliveSet(bool) {}
 
-// IsListening implements SocketOptionsHandler.IsListening.
-func (*DefaultSocketOptionsHandler) IsListening() bool { return false }
-
-// SocketOptions contains all the variables which store values for SOL_SOCKET
-// level options.
+// SocketOptions contains all the variables which store values for SOL_SOCKET,
+// SOL_IP and SOL_IPV6 level options.
 //
 // +stateify savable
 type SocketOptions struct {
@@ -88,6 +79,31 @@ type SocketOptions struct {
 	// keepAliveEnabled determines whether TCP keepalive is enabled for this
 	// socket.
 	keepAliveEnabled uint32
+
+	// multicastLoopEnabled determines whether multicast packets sent over a
+	// non-loopback interface will be looped back. Analogous to inet->mc_loop.
+	multicastLoopEnabled uint32
+
+	// receiveTOSEnabled is used to specify if the TOS ancillary message is
+	// passed with incoming packets.
+	receiveTOSEnabled uint32
+
+	// receiveTClassEnabled is used to specify if the IPV6_TCLASS ancillary
+	// message is passed with incoming packets.
+	receiveTClassEnabled uint32
+
+	// receivePacketInfoEnabled is used to specify if more inforamtion is
+	// provided with incoming packets such as interface index and address.
+	receivePacketInfoEnabled uint32
+
+	// hdrIncludeEnabled is used to indicate for a raw endpoint that all packets
+	// being written have an IP header and the endpoint should not attach an IP
+	// header.
+	hdrIncludedEnabled uint32
+
+	// v6OnlyEnabled is used to determine whether an IPv6 socket is to be
+	// restricted to sending and receiving IPv6 packets only.
+	v6OnlyEnabled uint32
 }
 
 // InitHandler initializes the handler. This must be called before using the
@@ -167,8 +183,64 @@ func (so *SocketOptions) SetKeepAlive(v bool) {
 	so.handler.OnKeepAliveSet(v)
 }
 
-// GetAcceptConn gets value for SO_ACCEPTCONN option.
-func (so *SocketOptions) GetAcceptConn() bool {
-	// This option is completely endpoint dependent and unsettable.
-	return so.handler.IsListening()
+// GetMulticastLoop gets value for IP_MULTICAST_LOOP option.
+func (so *SocketOptions) GetMulticastLoop() bool {
+	return atomic.LoadUint32(&so.multicastLoopEnabled) != 0
+}
+
+// SetMulticastLoop sets value for IP_MULTICAST_LOOP option.
+func (so *SocketOptions) SetMulticastLoop(v bool) {
+	storeAtomicBool(&so.multicastLoopEnabled, v)
+}
+
+// GetReceiveTOS gets value for IP_RECVTOS option.
+func (so *SocketOptions) GetReceiveTOS() bool {
+	return atomic.LoadUint32(&so.receiveTOSEnabled) != 0
+}
+
+// SetReceiveTOS sets value for IP_RECVTOS option.
+func (so *SocketOptions) SetReceiveTOS(v bool) {
+	storeAtomicBool(&so.receiveTOSEnabled, v)
+}
+
+// GetReceiveTClass gets value for IPV6_RECVTCLASS option.
+func (so *SocketOptions) GetReceiveTClass() bool {
+	return atomic.LoadUint32(&so.receiveTClassEnabled) != 0
+}
+
+// SetReceiveTClass sets value for IPV6_RECVTCLASS option.
+func (so *SocketOptions) SetReceiveTClass(v bool) {
+	storeAtomicBool(&so.receiveTClassEnabled, v)
+}
+
+// GetReceivePacketInfo gets value for IP_PKTINFO option.
+func (so *SocketOptions) GetReceivePacketInfo() bool {
+	return atomic.LoadUint32(&so.receivePacketInfoEnabled) != 0
+}
+
+// SetReceivePacketInfo sets value for IP_PKTINFO option.
+func (so *SocketOptions) SetReceivePacketInfo(v bool) {
+	storeAtomicBool(&so.receivePacketInfoEnabled, v)
+}
+
+// GetHeaderIncluded gets value for IP_HDRINCL option.
+func (so *SocketOptions) GetHeaderIncluded() bool {
+	return atomic.LoadUint32(&so.hdrIncludedEnabled) != 0
+}
+
+// SetHeaderIncluded sets value for IP_HDRINCL option.
+func (so *SocketOptions) SetHeaderIncluded(v bool) {
+	storeAtomicBool(&so.hdrIncludedEnabled, v)
+}
+
+// GetV6Only gets value for IPV6_V6ONLY option.
+func (so *SocketOptions) GetV6Only() bool {
+	return atomic.LoadUint32(&so.v6OnlyEnabled) != 0
+}
+
+// SetV6Only sets value for IPV6_V6ONLY option.
+//
+// Preconditions: the backing TCP or UDP endpoint must be in initial state.
+func (so *SocketOptions) SetV6Only(v bool) {
+	storeAtomicBool(&so.v6OnlyEnabled, v)
 }