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tailscale/wgengine/router/router.go

109 lines
3.6 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package router presents an interface to manipulate the host network
// stack's state.
package router
import (
"net/netip"
"reflect"
"github.com/tailscale/wireguard-go/tun"
"tailscale.com/net/netmon"
"tailscale.com/types/logger"
"tailscale.com/types/preftype"
)
// Router is responsible for managing the system network stack.
//
// There is typically only one instance of this interface per process.
type Router interface {
// Up brings the router up.
Up() error
// Set updates the OS network stack with a new Config. It may be
// called multiple times with identical Configs, which the
// implementation should handle gracefully.
Set(*Config) error
// UpdateMagicsockPort tells the OS network stack what port magicsock
// is currently listening on, so it can be threaded through firewalls
// and such. This is distinct from Set() since magicsock may rebind
// ports independently from the Config changing.
//
// network should be either "udp4" or "udp6".
UpdateMagicsockPort(port uint16, network string) error
// Close closes the router.
Close() error
}
// New returns a new Router for the current platform, using the
// provided tun device.
//
// If netMon is nil, it's not used. It's currently (2021-07-20) only
// used on Linux in some situations.
func New(logf logger.Logf, tundev tun.Device, netMon *netmon.Monitor) (Router, error) {
logf = logger.WithPrefix(logf, "router: ")
return newUserspaceRouter(logf, tundev, netMon)
}
// CleanUp restores the system network configuration to its original state
// in case the Tailscale daemon terminated without closing the router.
// No other state needs to be instantiated before this runs.
func CleanUp(logf logger.Logf, interfaceName string) {
cleanUp(logf, interfaceName)
}
// Config is the subset of Tailscale configuration that is relevant to
// the OS's network stack.
type Config struct {
// LocalAddrs are the address(es) for this node. This is
// typically one IPv4/32 (the 100.x.y.z CGNAT) and one
// IPv6/128 (Tailscale ULA).
LocalAddrs []netip.Prefix
// Routes are the routes that point into the Tailscale
// interface. These are the /32 and /128 routes to peers, as
// well as any other subnets that peers are advertising and
// this node has chosen to use.
Routes []netip.Prefix
// LocalRoutes are the routes that should not be routed through Tailscale.
// There are no priorities set in how these routes are added, normal
// routing rules apply.
LocalRoutes []netip.Prefix
// NewMTU is currently only used by the MacOS network extension
// app to set the MTU of the tun in the router configuration
// callback. If zero, the MTU is unchanged.
NewMTU int
// SubnetRoutes is the list of subnets that this node is
// advertising to other Tailscale nodes.
// As of 2023-10-11, this field is only used for network
// flow logging and is otherwise ignored.
SubnetRoutes []netip.Prefix
// Linux-only things below, ignored on other platforms.
SNATSubnetRoutes bool // SNAT traffic to local subnets
NetfilterMode preftype.NetfilterMode // how much to manage netfilter rules
NetfilterKind string // what kind of netfilter to use (nftables, iptables)
}
func (a *Config) Equal(b *Config) bool {
if a == nil && b == nil {
return true
}
if (a == nil) != (b == nil) {
return false
}
return reflect.DeepEqual(a, b)
}
// shutdownConfig is a routing configuration that removes all router
// state from the OS. It's the config used when callers pass in a nil
// Config.
var shutdownConfig = Config{}