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, 1 insertions, 26 deletions

diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 956232a44..4d45dcc42 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -813,33 +813,8 @@ type OutOfBandInlineOption int
 // a default TTL.
 type DefaultTTLOption uint8
 
-// StackSACKEnabled is used by stack.(*Stack).TransportProtocolOption to
-// enable/disable SACK support in TCP. See: https://tools.ietf.org/html/rfc2018.
-type StackSACKEnabled bool
-
-// StackDelayEnabled is used by stack.(Stack*).TransportProtocolOption to
-// enable/disable Nagle's algorithm in TCP.
-type StackDelayEnabled bool
-
-// StackSendBufferSizeOption is used by stack.(Stack*).TransportProtocolOption
-// to get/set the default, min and max send buffer sizes.
-type StackSendBufferSizeOption struct {
-	Min     int
-	Default int
-	Max     int
-}
-
-// StackReceiveBufferSizeOption is used by
-// stack.(Stack*).TransportProtocolOption to get/set the default, min and max
-// receive buffer sizes.
-type StackReceiveBufferSizeOption struct {
-	Min     int
-	Default int
-	Max     int
-}
-
 //
-// IPPacketInfo is the message struture for IP_PKTINFO.
+// IPPacketInfo is the message structure for IP_PKTINFO.
 //
 // +stateify savable
 type IPPacketInfo struct {