Add support for Stack level options.

Linux controls socket send/receive buffers using a few sysctl variables
  - net.core.rmem_default
  - net.core.rmem_max
  - net.core.wmem_max
  - net.core.wmem_default
  - net.ipv4.tcp_rmem
  - net.ipv4.tcp_wmem

The first 4 control the default socket buffer sizes for all sockets
raw/packet/tcp/udp and also the maximum permitted socket buffer that can be
specified in setsockopt(SOL_SOCKET, SO_(RCV|SND)BUF,...).

The last two control the TCP auto-tuning limits and override the default
specified in rmem_default/wmem_default as well as the max limits.

Netstack today only implements tcp_rmem/tcp_wmem and incorrectly uses it
to limit the maximum size in setsockopt() as well as uses it for raw/udp
sockets.

This changelist introduces the other 4 and updates the udp/raw sockets to use
the newly introduced variables. The values for min/max match the current
tcp_rmem/wmem values and the default value buffers for UDP/RAW sockets is
updated to match the linux value of 212KiB up from the really low current value
of 32 KiB.

Updates #3043
Fixes #3043

PiperOrigin-RevId: 318089805

1 files changed, 10 insertions, 10 deletions

diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 6a7977259..dd514d397 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -111,13 +111,13 @@ func newEndpoint(s *stack.Stack, netProto tcpip.NetworkProtocolNumber, transProt
 	}
 
 	// Override with stack defaults.
-	var ss tcpip.StackSendBufferSizeOption
-	if err := s.TransportProtocolOption(transProto, &ss); err == nil {
+	var ss stack.SendBufferSizeOption
+	if err := s.Option(&ss); err == nil {
 		e.sndBufSizeMax = ss.Default
 	}
 
-	var rs tcpip.StackReceiveBufferSizeOption
-	if err := s.TransportProtocolOption(transProto, &rs); err == nil {
+	var rs stack.ReceiveBufferSizeOption
+	if err := s.Option(&rs); err == nil {
 		e.rcvBufSizeMax = rs.Default
 	}
 
@@ -541,9 +541,9 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	case tcpip.SendBufferSizeOption:
 		// Make sure the send buffer size is within the min and max
 		// allowed.
-		var ss tcpip.StackSendBufferSizeOption
-		if err := e.stack.TransportProtocolOption(e.TransProto, &ss); err != nil {
-			panic(fmt.Sprintf("s.TransportProtocolOption(%d, %+v) = %s", e.TransProto, ss, err))
+		var ss stack.SendBufferSizeOption
+		if err := e.stack.Option(&ss); err != nil {
+			panic(fmt.Sprintf("s.Option(%#v) = %s", ss, err))
 		}
 		if v > ss.Max {
 			v = ss.Max
@@ -559,9 +559,9 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	case tcpip.ReceiveBufferSizeOption:
 		// Make sure the receive buffer size is within the min and max
 		// allowed.
-		var rs tcpip.StackReceiveBufferSizeOption
-		if err := e.stack.TransportProtocolOption(e.TransProto, &rs); err != nil {
-			panic(fmt.Sprintf("s.TransportProtocolOption(%d, %+v) = %s", e.TransProto, rs, err))
+		var rs stack.ReceiveBufferSizeOption
+		if err := e.stack.Option(&rs); err != nil {
+			panic(fmt.Sprintf("s.Option(%#v) = %s", rs, err))
 		}
 		if v > rs.Max {
 			v = rs.Max