traefik/pkg/muxer/tcp/matcher_v2.go

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2024-01-23 10:34:05 +00:00
package tcp
import (
"bytes"
"errors"
"fmt"
"regexp"
"strconv"
"strings"
"github.com/go-acme/lego/v4/challenge/tlsalpn01"
"github.com/rs/zerolog/log"
"github.com/traefik/traefik/v3/pkg/ip"
)
var tcpFuncsV2 = map[string]func(*matchersTree, ...string) error{
"ALPN": alpnV2,
"ClientIP": clientIPV2,
"HostSNI": hostSNIV2,
"HostSNIRegexp": hostSNIRegexpV2,
}
func clientIPV2(tree *matchersTree, clientIPs ...string) error {
checker, err := ip.NewChecker(clientIPs)
if err != nil {
return fmt.Errorf("could not initialize IP Checker for \"ClientIP\" matcher: %w", err)
}
tree.matcher = func(meta ConnData) bool {
if meta.remoteIP == "" {
return false
}
ok, err := checker.Contains(meta.remoteIP)
if err != nil {
log.Warn().Err(err).Msg("ClientIP matcher: could not match remote address")
return false
}
return ok
}
return nil
}
// alpnV2 checks if any of the connection ALPN protocols matches one of the matcher protocols.
func alpnV2(tree *matchersTree, protos ...string) error {
if len(protos) == 0 {
return errors.New("empty value for \"ALPN\" matcher is not allowed")
}
for _, proto := range protos {
if proto == tlsalpn01.ACMETLS1Protocol {
return fmt.Errorf("invalid protocol value for \"ALPN\" matcher, %q is not allowed", proto)
}
}
tree.matcher = func(meta ConnData) bool {
for _, proto := range meta.alpnProtos {
for _, filter := range protos {
if proto == filter {
return true
}
}
}
return false
}
return nil
}
// hostSNIV2 checks if the SNI Host of the connection match the matcher host.
func hostSNIV2(tree *matchersTree, hosts ...string) error {
if len(hosts) == 0 {
return errors.New("empty value for \"HostSNI\" matcher is not allowed")
}
for i, host := range hosts {
// Special case to allow global wildcard
if host == "*" {
continue
}
if !hostOrIP.MatchString(host) {
return fmt.Errorf("invalid value for \"HostSNI\" matcher, %q is not a valid hostname or IP", host)
}
hosts[i] = strings.ToLower(host)
}
tree.matcher = func(meta ConnData) bool {
// Since a HostSNI(`*`) rule has been provided as catchAll for non-TLS TCP,
// it allows matching with an empty serverName.
// Which is why we make sure to take that case into account before
// checking meta.serverName.
if hosts[0] == "*" {
return true
}
if meta.serverName == "" {
return false
}
for _, host := range hosts {
if host == "*" {
return true
}
if host == meta.serverName {
return true
}
// trim trailing period in case of FQDN
host = strings.TrimSuffix(host, ".")
if host == meta.serverName {
return true
}
}
return false
}
return nil
}
// hostSNIRegexpV2 checks if the SNI Host of the connection matches the matcher host regexp.
func hostSNIRegexpV2(tree *matchersTree, templates ...string) error {
if len(templates) == 0 {
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return errors.New("empty value for \"HostSNIRegexp\" matcher is not allowed")
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}
var regexps []*regexp.Regexp
for _, template := range templates {
preparedPattern, err := preparePattern(template)
if err != nil {
return fmt.Errorf("invalid pattern value for \"HostSNIRegexp\" matcher, %q is not a valid pattern: %w", template, err)
}
regexp, err := regexp.Compile(preparedPattern)
if err != nil {
return err
}
regexps = append(regexps, regexp)
}
tree.matcher = func(meta ConnData) bool {
for _, regexp := range regexps {
if regexp.MatchString(meta.serverName) {
return true
}
}
return false
}
return nil
}
// preparePattern builds a regexp pattern from the initial user defined expression.
// This function reuses the code dedicated to host matching of the newRouteRegexp func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func preparePattern(template string) (string, error) {
// Check if it is well-formed.
idxs, errBraces := braceIndices(template)
if errBraces != nil {
return "", errBraces
}
defaultPattern := "[^.]+"
pattern := bytes.NewBufferString("")
// Host SNI matching is case-insensitive
_, _ = fmt.Fprint(pattern, "(?i)")
pattern.WriteByte('^')
var end int
for i := 0; i < len(idxs); i += 2 {
// Set all values we are interested in.
raw := template[end:idxs[i]]
end = idxs[i+1]
parts := strings.SplitN(template[idxs[i]+1:end-1], ":", 2)
name := parts[0]
patt := defaultPattern
if len(parts) == 2 {
patt = parts[1]
}
// Name or pattern can't be empty.
if name == "" || patt == "" {
return "", fmt.Errorf("mux: missing name or pattern in %q",
template[idxs[i]:end])
}
// Build the regexp pattern.
_, _ = fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), varGroupName(i/2), patt)
}
// Add the remaining.
raw := template[end:]
pattern.WriteString(regexp.QuoteMeta(raw))
pattern.WriteByte('$')
return pattern.String(), nil
}
// varGroupName builds a capturing group name for the indexed variable.
// This function is a copy of varGroupName func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func varGroupName(idx int) string {
return "v" + strconv.Itoa(idx)
}
// braceIndices returns the first level curly brace indices from a string.
// This function is a copy of braceIndices func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func braceIndices(s string) ([]int, error) {
var level, idx int
var idxs []int
for i := 0; i < len(s); i++ {
switch s[i] {
case '{':
if level++; level == 1 {
idx = i
}
case '}':
if level--; level == 0 {
idxs = append(idxs, idx, i+1)
} else if level < 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
}
}
if level != 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
return idxs, nil
}