453 lines
11 KiB
Go
453 lines
11 KiB
Go
package tcp
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import (
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"bytes"
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"errors"
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"fmt"
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"net"
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"regexp"
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"sort"
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"strconv"
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"strings"
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"github.com/traefik/traefik/v2/pkg/ip"
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"github.com/traefik/traefik/v2/pkg/log"
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"github.com/traefik/traefik/v2/pkg/rules"
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"github.com/traefik/traefik/v2/pkg/tcp"
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"github.com/traefik/traefik/v2/pkg/types"
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"github.com/vulcand/predicate"
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)
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var tcpFuncs = map[string]func(*matchersTree, ...string) error{
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"HostSNI": hostSNI,
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"HostSNIRegexp": hostSNIRegexp,
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"ClientIP": clientIP,
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}
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// ParseHostSNI extracts the HostSNIs declared in a rule.
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// This is a first naive implementation used in TCP routing.
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func ParseHostSNI(rule string) ([]string, error) {
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var matchers []string
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for matcher := range tcpFuncs {
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matchers = append(matchers, matcher)
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}
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parser, err := rules.NewParser(matchers)
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if err != nil {
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return nil, err
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}
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parse, err := parser.Parse(rule)
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if err != nil {
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return nil, err
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}
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buildTree, ok := parse.(rules.TreeBuilder)
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if !ok {
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return nil, fmt.Errorf("error while parsing rule %s", rule)
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}
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return buildTree().ParseMatchers([]string{"HostSNI"}), nil
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}
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// ConnData contains TCP connection metadata.
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type ConnData struct {
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serverName string
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remoteIP string
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}
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// NewConnData builds a connData struct from the given parameters.
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func NewConnData(serverName string, conn tcp.WriteCloser) (ConnData, error) {
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remoteIP, _, err := net.SplitHostPort(conn.RemoteAddr().String())
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if err != nil {
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return ConnData{}, fmt.Errorf("error while parsing remote address %q: %w", conn.RemoteAddr().String(), err)
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}
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// as per https://datatracker.ietf.org/doc/html/rfc6066:
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// > The hostname is represented as a byte string using ASCII encoding without a trailing dot.
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// so there is no need to trim a potential trailing dot
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serverName = types.CanonicalDomain(serverName)
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return ConnData{
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serverName: types.CanonicalDomain(serverName),
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remoteIP: remoteIP,
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}, nil
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}
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// Muxer defines a muxer that handles TCP routing with rules.
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type Muxer struct {
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routes []*route
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parser predicate.Parser
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}
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// NewMuxer returns a TCP muxer.
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func NewMuxer() (*Muxer, error) {
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var matcherNames []string
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for matcherName := range tcpFuncs {
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matcherNames = append(matcherNames, matcherName)
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}
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parser, err := rules.NewParser(matcherNames)
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if err != nil {
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return nil, fmt.Errorf("error while creating rules parser: %w", err)
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}
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return &Muxer{parser: parser}, nil
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}
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// Match returns the handler of the first route matching the connection metadata.
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func (m Muxer) Match(meta ConnData) tcp.Handler {
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for _, route := range m.routes {
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if route.matchers.match(meta) {
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return route.handler
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}
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}
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return nil
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}
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// AddRoute adds a new route, associated to the given handler, at the given
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// priority, to the muxer.
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func (m *Muxer) AddRoute(rule string, priority int, handler tcp.Handler) error {
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// Special case for when the catchAll fallback is present.
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// When no user-defined priority is found, the lowest computable priority minus one is used,
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// in order to make the fallback the last to be evaluated.
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if priority == 0 && rule == "HostSNI(`*`)" {
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priority = -1
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}
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// Default value, which means the user has not set it, so we'll compute it.
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if priority == 0 {
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priority = len(rule)
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}
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parse, err := m.parser.Parse(rule)
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if err != nil {
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return fmt.Errorf("error while parsing rule %s: %w", rule, err)
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}
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buildTree, ok := parse.(rules.TreeBuilder)
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if !ok {
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return fmt.Errorf("error while parsing rule %s", rule)
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}
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var matchers matchersTree
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err = addRule(&matchers, buildTree())
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if err != nil {
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return err
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}
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newRoute := &route{
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handler: handler,
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priority: priority,
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matchers: matchers,
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}
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m.routes = append(m.routes, newRoute)
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sort.Sort(routes(m.routes))
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return nil
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}
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func addRule(tree *matchersTree, rule *rules.Tree) error {
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switch rule.Matcher {
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case "and", "or":
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tree.operator = rule.Matcher
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tree.left = &matchersTree{}
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err := addRule(tree.left, rule.RuleLeft)
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if err != nil {
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return err
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}
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tree.right = &matchersTree{}
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return addRule(tree.right, rule.RuleRight)
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default:
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err := rules.CheckRule(rule)
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if err != nil {
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return err
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}
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err = tcpFuncs[rule.Matcher](tree, rule.Value...)
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if err != nil {
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return err
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}
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if rule.Not {
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matcherFunc := tree.matcher
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tree.matcher = func(meta ConnData) bool {
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return !matcherFunc(meta)
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}
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}
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}
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return nil
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}
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// HasRoutes returns whether the muxer has routes.
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func (m *Muxer) HasRoutes() bool {
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return len(m.routes) > 0
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}
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// routes implements sort.Interface.
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type routes []*route
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// Len implements sort.Interface.
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func (r routes) Len() int { return len(r) }
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// Swap implements sort.Interface.
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func (r routes) Swap(i, j int) { r[i], r[j] = r[j], r[i] }
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// Less implements sort.Interface.
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func (r routes) Less(i, j int) bool { return r[i].priority > r[j].priority }
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// route holds the matchers to match TCP route,
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// and the handler that will serve the connection.
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type route struct {
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// matchers tree structure reflecting the rule.
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matchers matchersTree
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// handler responsible for handling the route.
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handler tcp.Handler
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// Used to disambiguate between two (or more) rules that would both match for a
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// given request.
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// Computed from the matching rule length, if not user-set.
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priority int
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}
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// matcher is a matcher func used to match connection properties.
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type matcher func(meta ConnData) bool
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// matchersTree represents the matchers tree structure.
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type matchersTree struct {
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// If matcher is not nil, it means that this matcherTree is a leaf of the tree.
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// It is therefore mutually exclusive with left and right.
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matcher matcher
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// operator to combine the evaluation of left and right leaves.
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operator string
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// Mutually exclusive with matcher.
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left *matchersTree
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right *matchersTree
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}
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func (m *matchersTree) match(meta ConnData) bool {
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if m == nil {
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// This should never happen as it should have been detected during parsing.
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log.WithoutContext().Warnf("Rule matcher is nil")
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return false
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}
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if m.matcher != nil {
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return m.matcher(meta)
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}
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switch m.operator {
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case "or":
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return m.left.match(meta) || m.right.match(meta)
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case "and":
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return m.left.match(meta) && m.right.match(meta)
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default:
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// This should never happen as it should have been detected during parsing.
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log.WithoutContext().Warnf("Invalid rule operator %s", m.operator)
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return false
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}
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}
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func clientIP(tree *matchersTree, clientIPs ...string) error {
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checker, err := ip.NewChecker(clientIPs)
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if err != nil {
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return fmt.Errorf("could not initialize IP Checker for \"ClientIP\" matcher: %w", err)
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}
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tree.matcher = func(meta ConnData) bool {
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if meta.remoteIP == "" {
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return false
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}
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ok, err := checker.Contains(meta.remoteIP)
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if err != nil {
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log.WithoutContext().Warnf("\"ClientIP\" matcher: could not match remote address: %v", err)
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return false
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}
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return ok
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}
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return nil
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}
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var almostFQDN = regexp.MustCompile(`^[[:alnum:]\.-]+$`)
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// hostSNI checks if the SNI Host of the connection match the matcher host.
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func hostSNI(tree *matchersTree, hosts ...string) error {
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if len(hosts) == 0 {
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return errors.New("empty value for \"HostSNI\" matcher is not allowed")
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}
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for i, host := range hosts {
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// Special case to allow global wildcard
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if host == "*" {
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continue
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}
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if !almostFQDN.MatchString(host) {
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return fmt.Errorf("invalid value for \"HostSNI\" matcher, %q is not a valid hostname", host)
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}
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hosts[i] = strings.ToLower(host)
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}
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tree.matcher = func(meta ConnData) bool {
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// Since a HostSNI(`*`) rule has been provided as catchAll for non-TLS TCP,
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// it allows matching with an empty serverName.
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// Which is why we make sure to take that case into account before
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// checking meta.serverName.
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if hosts[0] == "*" {
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return true
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}
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if meta.serverName == "" {
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return false
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}
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for _, host := range hosts {
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if host == "*" {
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return true
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}
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if host == meta.serverName {
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return true
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}
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// trim trailing period in case of FQDN
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host = strings.TrimSuffix(host, ".")
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if host == meta.serverName {
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return true
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}
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}
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return false
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}
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return nil
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}
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// hostSNIRegexp checks if the SNI Host of the connection matches the matcher host regexp.
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func hostSNIRegexp(tree *matchersTree, templates ...string) error {
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if len(templates) == 0 {
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return fmt.Errorf("empty value for \"HostSNIRegexp\" matcher is not allowed")
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}
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var regexps []*regexp.Regexp
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for _, template := range templates {
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preparedPattern, err := preparePattern(template)
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if err != nil {
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return fmt.Errorf("invalid pattern value for \"HostSNIRegexp\" matcher, %q is not a valid pattern: %w", template, err)
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}
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regexp, err := regexp.Compile(preparedPattern)
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if err != nil {
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return err
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}
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regexps = append(regexps, regexp)
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}
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tree.matcher = func(meta ConnData) bool {
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for _, regexp := range regexps {
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if regexp.MatchString(meta.serverName) {
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return true
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}
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}
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return false
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}
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return nil
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}
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// TODO: expose more of containous/mux fork to get rid of the following copied code (https://github.com/containous/mux/blob/8ffa4f6d063c/regexp.go).
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// preparePattern builds a regexp pattern from the initial user defined expression.
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// This function reuses the code dedicated to host matching of the newRouteRegexp func from the gorilla/mux library.
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// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
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func preparePattern(template string) (string, error) {
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// Check if it is well-formed.
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idxs, errBraces := braceIndices(template)
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if errBraces != nil {
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return "", errBraces
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}
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defaultPattern := "[^.]+"
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pattern := bytes.NewBufferString("")
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// Host SNI matching is case-insensitive
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fmt.Fprint(pattern, "(?i)")
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pattern.WriteByte('^')
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var end int
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var err error
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for i := 0; i < len(idxs); i += 2 {
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// Set all values we are interested in.
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raw := template[end:idxs[i]]
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end = idxs[i+1]
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parts := strings.SplitN(template[idxs[i]+1:end-1], ":", 2)
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name := parts[0]
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patt := defaultPattern
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if len(parts) == 2 {
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patt = parts[1]
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}
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// Name or pattern can't be empty.
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if name == "" || patt == "" {
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return "", fmt.Errorf("mux: missing name or pattern in %q",
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template[idxs[i]:end])
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}
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// Build the regexp pattern.
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fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), varGroupName(i/2), patt)
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// Append variable name and compiled pattern.
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if err != nil {
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return "", err
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}
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}
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// Add the remaining.
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raw := template[end:]
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pattern.WriteString(regexp.QuoteMeta(raw))
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pattern.WriteByte('$')
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return pattern.String(), nil
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}
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// varGroupName builds a capturing group name for the indexed variable.
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// This function is a copy of varGroupName func from the gorilla/mux library.
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// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
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func varGroupName(idx int) string {
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return "v" + strconv.Itoa(idx)
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}
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// braceIndices returns the first level curly brace indices from a string.
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// This function is a copy of braceIndices func from the gorilla/mux library.
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// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
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func braceIndices(s string) ([]int, error) {
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var level, idx int
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var idxs []int
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for i := 0; i < len(s); i++ {
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switch s[i] {
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case '{':
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if level++; level == 1 {
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idx = i
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}
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case '}':
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if level--; level == 0 {
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idxs = append(idxs, idx, i+1)
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} else if level < 0 {
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return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
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}
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}
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}
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if level != 0 {
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return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
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}
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return idxs, nil
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}
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