String (filter/filter.go)

Go packet filter for Tailscale, providing stateful ingress/egress filtering, hooks, and logging with configurable rules.

// Source: https://github.com/tailscale/tailscale | License: BSD-3-Clause | Copyright 2020 Tailscale Inc & contributors
// Provided via justclaw.it.com; keep this notice with the code.
// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause

// Package filter is a stateful packet filter.
package filter

import (
	"fmt"
	"net/netip"
	"slices"
	"sync"
	"time"

	"go4.org/netipx"
	"tailscale.com/envknob"
	"tailscale.com/net/flowtrack"
	"tailscale.com/net/ipset"
	"tailscale.com/net/netaddr"
	"tailscale.com/net/packet"
	"tailscale.com/tailcfg"
	"tailscale.com/tstime/rate"
	"tailscale.com/types/ipproto"
	"tailscale.com/types/logger"
	"tailscale.com/types/views"
	"tailscale.com/util/mak"
	"tailscale.com/util/slicesx"
	"tailscale.com/util/usermetric"
	"tailscale.com/w

... (truncated -- full source via MCP)