tailscale/ipn/serve.go
Marwan Sulaiman 3421784e37 cmd/tailscale/cli: use optimistic concurrency control on SetServeConfig
This PR uses the etag/if-match pattern to ensure multiple calls
to SetServeConfig are synchronized. It currently errors out and
asks the user to retry but we can add occ retries as a follow up.

Updates #8489

Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>
2023-09-13 15:08:41 -05:00

407 lines
12 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package ipn
import (
"errors"
"fmt"
"net"
"net/netip"
"net/url"
"slices"
"strconv"
"strings"
"tailscale.com/tailcfg"
)
// ServeConfigKey returns a StateKey that stores the
// JSON-encoded ServeConfig for a config profile.
func ServeConfigKey(profileID ProfileID) StateKey {
return StateKey("_serve/" + profileID)
}
// ServeConfig is the JSON type stored in the StateStore for
// StateKey "_serve/$PROFILE_ID" as returned by ServeConfigKey.
type ServeConfig struct {
// TCP are the list of TCP port numbers that tailscaled should handle for
// the Tailscale IP addresses. (not subnet routers, etc)
TCP map[uint16]*TCPPortHandler `json:",omitempty"`
// Web maps from "$SNI_NAME:$PORT" to a set of HTTP handlers
// keyed by mount point ("/", "/foo", etc)
Web map[HostPort]*WebServerConfig `json:",omitempty"`
// AllowFunnel is the set of SNI:port values for which funnel
// traffic is allowed, from trusted ingress peers.
AllowFunnel map[HostPort]bool `json:",omitempty"`
// Foreground is a map of an IPN Bus session ID to an alternate foreground
// serve config that's valid for the life of that WatchIPNBus session ID.
// This. This allows the config to specify ephemeral configs that are
// used in the CLI's foreground mode to ensure ungraceful shutdowns
// of either the client or the LocalBackend does not expose ports
// that users are not aware of.
Foreground map[string]*ServeConfig `json:",omitempty"`
// ETag is the checksum of the serve config that's populated
// by the LocalClient through the HTTP ETag header during a
// GetServeConfig request and is translated to an If-Match header
// during a SetServeConfig request.
ETag string `json:"-"`
}
// HostPort is an SNI name and port number, joined by a colon.
// There is no implicit port 443. It must contain a colon.
type HostPort string
// Port extracts just the port number from hp.
// An error is reported in the case that the hp does not
// have a valid numeric port ending.
func (hp HostPort) Port() (uint16, error) {
_, port, err := net.SplitHostPort(string(hp))
if err != nil {
return 0, err
}
port16, err := strconv.ParseUint(port, 10, 16)
if err != nil {
return 0, err
}
return uint16(port16), nil
}
// A FunnelConn wraps a net.Conn that is coming over a
// Funnel connection. It can be used to determine further
// information about the connection, like the source address
// and the target SNI name.
type FunnelConn struct {
// Conn is the underlying connection.
net.Conn
// Target is what was presented in the "Tailscale-Ingress-Target"
// HTTP header.
Target HostPort
// Src is the source address of the connection.
// This is the address of the client that initiated the
// connection, not the address of the Tailscale Funnel
// node which is relaying the connection. That address
// can be found in Conn.RemoteAddr.
Src netip.AddrPort
}
// WebServerConfig describes a web server's configuration.
type WebServerConfig struct {
Handlers map[string]*HTTPHandler // mountPoint => handler
}
// TCPPortHandler describes what to do when handling a TCP
// connection.
type TCPPortHandler struct {
// HTTPS, if true, means that tailscaled should handle this connection as an
// HTTPS request as configured by ServeConfig.Web.
//
// It is mutually exclusive with TCPForward.
HTTPS bool `json:",omitempty"`
// HTTP, if true, means that tailscaled should handle this connection as an
// HTTP request as configured by ServeConfig.Web.
//
// It is mutually exclusive with TCPForward.
HTTP bool `json:",omitempty"`
// TCPForward is the IP:port to forward TCP connections to.
// Whether or not TLS is terminated by tailscaled depends on
// TerminateTLS.
//
// It is mutually exclusive with HTTPS.
TCPForward string `json:",omitempty"`
// TerminateTLS, if non-empty, means that tailscaled should terminate the
// TLS connections before forwarding them to TCPForward, permitting only the
// SNI name with this value. It is only used if TCPForward is non-empty.
// (the HTTPS mode uses ServeConfig.Web)
TerminateTLS string `json:",omitempty"`
}
// HTTPHandler is either a path or a proxy to serve.
type HTTPHandler struct {
// Exactly one of the following may be set.
Path string `json:",omitempty"` // absolute path to directory or file to serve
Proxy string `json:",omitempty"` // http://localhost:3000/, localhost:3030, 3030
Text string `json:",omitempty"` // plaintext to serve (primarily for testing)
// TODO(bradfitz): bool to not enumerate directories? TTL on mapping for
// temporary ones? Error codes? Redirects?
}
// WebHandlerExists reports whether if the ServeConfig Web handler exists for
// the given host:port and mount point.
func (sc *ServeConfig) WebHandlerExists(hp HostPort, mount string) bool {
h := sc.GetWebHandler(hp, mount)
return h != nil
}
// GetWebHandler returns the HTTPHandler for the given host:port and mount point.
// Returns nil if the handler does not exist.
func (sc *ServeConfig) GetWebHandler(hp HostPort, mount string) *HTTPHandler {
if sc == nil || sc.Web[hp] == nil {
return nil
}
return sc.Web[hp].Handlers[mount]
}
// GetTCPPortHandler returns the TCPPortHandler for the given port.
// If the port is not configured, nil is returned.
func (sc *ServeConfig) GetTCPPortHandler(port uint16) *TCPPortHandler {
if sc == nil {
return nil
}
return sc.TCP[port]
}
// IsTCPForwardingAny reports whether ServeConfig is currently forwarding in
// TCPForward mode on any port. This is exclusive of Web/HTTPS serving.
func (sc *ServeConfig) IsTCPForwardingAny() bool {
if sc == nil || len(sc.TCP) == 0 {
return false
}
for _, h := range sc.TCP {
if h.TCPForward != "" {
return true
}
}
return false
}
// IsTCPForwardingOnPort reports whether if ServeConfig is currently forwarding
// in TCPForward mode on the given port. This is exclusive of Web/HTTPS serving.
func (sc *ServeConfig) IsTCPForwardingOnPort(port uint16) bool {
if sc == nil || sc.TCP[port] == nil {
return false
}
return !sc.IsServingWeb(port)
}
// IsServingWeb reports whether if ServeConfig is currently serving Web
// (HTTP/HTTPS) on the given port. This is exclusive of TCPForwarding.
func (sc *ServeConfig) IsServingWeb(port uint16) bool {
return sc.IsServingHTTP(port) || sc.IsServingHTTPS(port)
}
// IsServingHTTPS reports whether if ServeConfig is currently serving HTTPS on
// the given port. This is exclusive of HTTP and TCPForwarding.
func (sc *ServeConfig) IsServingHTTPS(port uint16) bool {
if sc == nil || sc.TCP[port] == nil {
return false
}
return sc.TCP[port].HTTPS
}
// IsServingHTTP reports whether if ServeConfig is currently serving HTTP on the
// given port. This is exclusive of HTTPS and TCPForwarding.
func (sc *ServeConfig) IsServingHTTP(port uint16) bool {
if sc == nil || sc.TCP[port] == nil {
return false
}
return sc.TCP[port].HTTP
}
// IsFunnelOn reports whether if ServeConfig is currently allowing funnel
// traffic for any host:port.
//
// View version of ServeConfig.IsFunnelOn.
func (v ServeConfigView) IsFunnelOn() bool { return v.ж.IsFunnelOn() }
// IsFunnelOn reports whether if ServeConfig is currently allowing funnel
// traffic for any host:port.
func (sc *ServeConfig) IsFunnelOn() bool {
if sc == nil {
return false
}
for _, b := range sc.AllowFunnel {
if b {
return true
}
}
return false
}
// CheckFunnelAccess checks whether Funnel access is allowed for the given node
// and port.
// It checks:
// 1. HTTPS is enabled on the Tailnet
// 2. the node has the "funnel" nodeAttr
// 3. the port is allowed for Funnel
//
// The nodeAttrs arg should be the node's Self.Capabilities which should contain
// the attribute we're checking for and possibly warning-capabilities for
// Funnel.
func CheckFunnelAccess(port uint16, nodeAttrs []string) error {
if !slices.Contains(nodeAttrs, tailcfg.CapabilityHTTPS) {
return errors.New("Funnel not available; HTTPS must be enabled. See https://tailscale.com/s/https.")
}
if !slices.Contains(nodeAttrs, tailcfg.NodeAttrFunnel) {
return errors.New("Funnel not available; \"funnel\" node attribute not set. See https://tailscale.com/s/no-funnel.")
}
return CheckFunnelPort(port, nodeAttrs)
}
// CheckFunnelPort checks whether the given port is allowed for Funnel.
// It uses the tailcfg.CapabilityFunnelPorts nodeAttr to determine the allowed
// ports.
func CheckFunnelPort(wantedPort uint16, nodeAttrs []string) error {
deny := func(allowedPorts string) error {
if allowedPorts == "" {
return fmt.Errorf("port %d is not allowed for funnel", wantedPort)
}
return fmt.Errorf("port %d is not allowed for funnel; allowed ports are: %v", wantedPort, allowedPorts)
}
var portsStr string
for _, attr := range nodeAttrs {
if !strings.HasPrefix(attr, tailcfg.CapabilityFunnelPorts) {
continue
}
u, err := url.Parse(attr)
if err != nil {
return deny("")
}
portsStr = u.Query().Get("ports")
if portsStr == "" {
return deny("")
}
u.RawQuery = ""
if u.String() != tailcfg.CapabilityFunnelPorts {
return deny("")
}
}
wantedPortString := strconv.Itoa(int(wantedPort))
for _, ps := range strings.Split(portsStr, ",") {
if ps == "" {
continue
}
first, last, ok := strings.Cut(ps, "-")
if !ok {
if first == wantedPortString {
return nil
}
continue
}
fp, err := strconv.ParseUint(first, 10, 16)
if err != nil {
continue
}
lp, err := strconv.ParseUint(last, 10, 16)
if err != nil {
continue
}
pr := tailcfg.PortRange{First: uint16(fp), Last: uint16(lp)}
if pr.Contains(wantedPort) {
return nil
}
}
return deny(portsStr)
}
// RangeOverTCPs ranges over both background and foreground TCPs.
// If the returned bool from the given f is false, then this function stops
// iterating immediately and does not check other foreground configs.
func (v ServeConfigView) RangeOverTCPs(f func(port uint16, _ TCPPortHandlerView) bool) {
parentCont := true
v.TCP().Range(func(k uint16, v TCPPortHandlerView) (cont bool) {
parentCont = f(k, v)
return parentCont
})
v.Foreground().Range(func(k string, v ServeConfigView) (cont bool) {
if !parentCont {
return false
}
v.TCP().Range(func(k uint16, v TCPPortHandlerView) (cont bool) {
parentCont = f(k, v)
return parentCont
})
return parentCont
})
}
// RangeOverWebs ranges over both background and foreground Webs.
// If the returned bool from the given f is false, then this function stops
// iterating immediately and does not check other foreground configs.
func (v ServeConfigView) RangeOverWebs(f func(_ HostPort, conf WebServerConfigView) bool) {
parentCont := true
v.Web().Range(func(k HostPort, v WebServerConfigView) (cont bool) {
parentCont = f(k, v)
return parentCont
})
v.Foreground().Range(func(k string, v ServeConfigView) (cont bool) {
if !parentCont {
return false
}
v.Web().Range(func(k HostPort, v WebServerConfigView) (cont bool) {
parentCont = f(k, v)
return parentCont
})
return parentCont
})
}
// FindTCP returns the first TCP that matches with the given port. It
// prefers a foreground match first followed by a background search if none
// existed.
func (v ServeConfigView) FindTCP(port uint16) (res TCPPortHandlerView, ok bool) {
v.Foreground().Range(func(_ string, v ServeConfigView) (cont bool) {
res, ok = v.TCP().GetOk(port)
return !ok
})
if ok {
return res, ok
}
return v.TCP().GetOk(port)
}
// FindWeb returns the first Web that matches with the given HostPort. It
// prefers a foreground match first followed by a background search if none
// existed.
func (v ServeConfigView) FindWeb(hp HostPort) (res WebServerConfigView, ok bool) {
v.Foreground().Range(func(_ string, v ServeConfigView) (cont bool) {
res, ok = v.Web().GetOk(hp)
return !ok
})
if ok {
return res, ok
}
return v.Web().GetOk(hp)
}
// HasAllowFunnel returns whether this config has at least one AllowFunnel
// set in the background or foreground configs.
func (v ServeConfigView) HasAllowFunnel() bool {
return v.AllowFunnel().Len() > 0 || func() bool {
var exists bool
v.Foreground().Range(func(k string, v ServeConfigView) (cont bool) {
exists = v.AllowFunnel().Len() > 0
return !exists
})
return exists
}()
}
// FindFunnel reports whether target exists in in either the background AllowFunnel
// or any of the foreground configs.
func (v ServeConfigView) HasFunnelForTarget(target HostPort) bool {
if v.AllowFunnel().Get(target) {
return true
}
var exists bool
v.Foreground().Range(func(_ string, v ServeConfigView) (cont bool) {
if exists = v.AllowFunnel().Get(target); exists {
return false
}
return true
})
return exists
}