mirror of https://github.com/hashicorp/consul
107 lines
3.0 KiB
Go
107 lines
3.0 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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package dns
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import (
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"fmt"
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"github.com/hashicorp/consul/agent/structs"
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"github.com/hashicorp/consul/internal/dnsutil"
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"net"
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"github.com/miekg/dns"
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"github.com/hashicorp/go-hclog"
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"github.com/hashicorp/consul/acl"
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"github.com/hashicorp/consul/agent/config"
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"github.com/hashicorp/consul/logging"
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)
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// DNSRouter is a mock for Router that can be used for testing.
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//
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//go:generate mockery --name DNSRouter --inpackage
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type DNSRouter interface {
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HandleRequest(req *dns.Msg, reqCtx Context, remoteAddress net.Addr) *dns.Msg
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ServeDNS(w dns.ResponseWriter, req *dns.Msg)
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GetConfig() *RouterDynamicConfig
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ReloadConfig(newCfg *config.RuntimeConfig) error
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}
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// Server is used to expose service discovery queries using a DNS interface.
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// It implements the agent.dnsServer interface.
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type Server struct {
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*dns.Server // Used for setting up listeners
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Router DNSRouter // Used to routes and parse DNS requests
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logger hclog.Logger
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}
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// Config represent all the DNS configuration required to construct a DNS server.
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type Config struct {
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AgentConfig *config.RuntimeConfig
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EntMeta acl.EnterpriseMeta
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Logger hclog.Logger
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Processor DiscoveryQueryProcessor
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TokenFunc func() string
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TranslateAddressFunc func(dc string, addr string, taggedAddresses map[string]string, accept dnsutil.TranslateAddressAccept) string
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TranslateServiceAddressFunc func(dc string, address string, taggedAddresses map[string]structs.ServiceAddress, accept dnsutil.TranslateAddressAccept) string
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}
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// NewServer creates a new DNS server.
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func NewServer(config Config) (*Server, error) {
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router, err := NewRouter(config)
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if err != nil {
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return nil, fmt.Errorf("error creating DNS router: %w", err)
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}
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srv := &Server{
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Router: router,
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logger: config.Logger.Named(logging.DNS),
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}
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return srv, nil
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}
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// ListenAndServe starts the DNS server.
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func (d *Server) ListenAndServe(network, addr string, notif func()) error {
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d.Server = &dns.Server{
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Addr: addr,
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Net: network,
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Handler: d.Router,
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NotifyStartedFunc: notif,
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}
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if network == "udp" {
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d.UDPSize = 65535
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}
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return d.Server.ListenAndServe()
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}
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// ReloadConfig hot-reloads the server config with new parameters under config.RuntimeConfig.DNS*
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func (d *Server) ReloadConfig(newCfg *config.RuntimeConfig) error {
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return d.Router.ReloadConfig(newCfg)
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}
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// Shutdown stops the DNS server.
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func (d *Server) Shutdown() {
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if d.Server != nil {
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d.logger.Info("Stopping server",
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"protocol", "DNS",
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"address", d.Server.Addr,
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"network", d.Server.Net,
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)
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err := d.Server.Shutdown()
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if err != nil {
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d.logger.Error("Error stopping DNS server", "error", err)
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}
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}
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d.Router = nil
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}
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// GetAddr is a function to return the server address if is not nil.
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func (d *Server) GetAddr() string {
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if d.Server != nil {
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return d.Server.Addr
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}
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return ""
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}
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