wgengine/magicsock,net/sockopts: export Windows ICMP suppression logic (#16917)

For eventual use by net/udprelay.Server.

Updates tailscale/corp#31506

Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit is contained in:
Jordan Whited 2025-08-21 13:44:13 -07:00 committed by GitHub
parent cf739256ca
commit b17cfe4aed
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7 changed files with 27 additions and 21 deletions

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@ -867,7 +867,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
tailscale.com/net/portmapper from tailscale.com/ipn/localapi+
tailscale.com/net/proxymux from tailscale.com/tsnet
tailscale.com/net/routetable from tailscale.com/doctor/routetable
tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
💣 tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
tailscale.com/net/socks5 from tailscale.com/tsnet
tailscale.com/net/sockstats from tailscale.com/control/controlclient+
tailscale.com/net/stun from tailscale.com/ipn/localapi+

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@ -339,7 +339,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
tailscale.com/net/portmapper from tailscale.com/ipn/localapi+
tailscale.com/net/proxymux from tailscale.com/cmd/tailscaled
tailscale.com/net/routetable from tailscale.com/doctor/routetable
tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock+
💣 tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock+
tailscale.com/net/socks5 from tailscale.com/cmd/tailscaled
tailscale.com/net/sockstats from tailscale.com/control/controlclient+
tailscale.com/net/stun from tailscale.com/ipn/localapi+

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@ -297,7 +297,7 @@ tailscale.com/cmd/tsidp dependencies: (generated by github.com/tailscale/depawar
tailscale.com/net/portmapper from tailscale.com/ipn/localapi+
tailscale.com/net/proxymux from tailscale.com/tsnet
tailscale.com/net/routetable from tailscale.com/doctor/routetable
tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
💣 tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
tailscale.com/net/socks5 from tailscale.com/tsnet
tailscale.com/net/sockstats from tailscale.com/control/controlclient+
tailscale.com/net/stun from tailscale.com/ipn/localapi+

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@ -3,11 +3,13 @@
//go:build !windows
package magicsock
package sockopts
import (
"tailscale.com/types/logger"
"tailscale.com/types/nettype"
)
func trySetUDPSocketOptions(pconn nettype.PacketConn, logf logger.Logf) {}
// SetICMPErrImmunity is no-op on non-Windows.
func SetICMPErrImmunity(pconn nettype.PacketConn) error {
return nil
}

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@ -3,28 +3,31 @@
//go:build windows
package magicsock
package sockopts
import (
"fmt"
"net"
"unsafe"
"golang.org/x/sys/windows"
"tailscale.com/types/logger"
"tailscale.com/types/nettype"
)
func trySetUDPSocketOptions(pconn nettype.PacketConn, logf logger.Logf) {
// SetICMPErrImmunity sets socket options on pconn to prevent ICMP reception,
// e.g. ICMP Port Unreachable, from surfacing as a syscall error.
//
// If pconn is not a [*net.UDPConn], then SetICMPErrImmunity is no-op.
func SetICMPErrImmunity(pconn nettype.PacketConn) error {
c, ok := pconn.(*net.UDPConn)
if !ok {
// not a UDP connection; nothing to do
return
return nil
}
sysConn, err := c.SyscallConn()
if err != nil {
logf("trySetUDPSocketOptions: getting SyscallConn failed: %v", err)
return
return fmt.Errorf("SetICMPErrImmunity: getting SyscallConn failed: %v", err)
}
// Similar to https://github.com/golang/go/issues/5834 (which involved
@ -50,9 +53,10 @@ func trySetUDPSocketOptions(pconn nettype.PacketConn, logf logger.Logf) {
)
})
if ioctlErr != nil {
logf("trySetUDPSocketOptions: could not set SIO_UDP_NETRESET: %v", ioctlErr)
return fmt.Errorf("SetICMPErrImmunity: could not set SIO_UDP_NETRESET: %v", ioctlErr)
}
if err != nil {
logf("trySetUDPSocketOptions: SyscallConn.Control failed: %v", err)
return fmt.Errorf("SetICMPErrImmunity: SyscallConn.Control failed: %v", err)
}
return nil
}

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@ -293,7 +293,7 @@ tailscale.com/tsnet dependencies: (generated by github.com/tailscale/depaware)
tailscale.com/net/portmapper from tailscale.com/ipn/localapi+
tailscale.com/net/proxymux from tailscale.com/tsnet
tailscale.com/net/routetable from tailscale.com/doctor/routetable
tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
💣 tailscale.com/net/sockopts from tailscale.com/wgengine/magicsock
tailscale.com/net/socks5 from tailscale.com/tsnet
tailscale.com/net/sockstats from tailscale.com/control/controlclient+
tailscale.com/net/stun from tailscale.com/ipn/localapi+

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@ -3537,7 +3537,6 @@ func (c *Conn) bindSocket(ruc *RebindingUDPConn, network string, curPortFate cur
}
}
}
trySetSocketBuffer(pconn, c.logf)
trySetUDPSocketOptions(pconn, c.logf)
// Success.
@ -3858,11 +3857,7 @@ func (c *Conn) DebugForcePreferDERP(n int) {
c.netChecker.SetForcePreferredDERP(n)
}
// trySetSocketBuffer attempts to set SO_SNDBUFFORCE and SO_RECVBUFFORCE which
// can overcome the limit of net.core.{r,w}mem_max, but require CAP_NET_ADMIN.
// It falls back to the portable implementation if that fails, which may be
// silently capped to net.core.{r,w}mem_max.
func trySetSocketBuffer(pconn nettype.PacketConn, logf logger.Logf) {
func trySetUDPSocketOptions(pconn nettype.PacketConn, logf logger.Logf) {
directions := []sockopts.BufferDirection{sockopts.ReadDirection, sockopts.WriteDirection}
for _, direction := range directions {
forceErr, portableErr := sockopts.SetBufferSize(pconn, direction, socketBufferSize)
@ -3873,6 +3868,11 @@ func trySetSocketBuffer(pconn nettype.PacketConn, logf logger.Logf) {
logf("magicsock: failed to set UDP %v buffer size to %d: %v", direction, socketBufferSize, portableErr)
}
}
err := sockopts.SetICMPErrImmunity(pconn)
if err != nil {
logf("magicsock: %v", err)
}
}
// derpStr replaces DERP IPs in s with "derp-".