forked from coredns/coredns
/
register.go
209 lines (178 loc) · 5.55 KB
/
register.go
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package dnsserver
import (
"flag"
"fmt"
"net"
"strings"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/pkg/dnsutil"
"github.com/mholt/caddy"
"github.com/mholt/caddy/caddyfile"
)
const serverType = "dns"
// Any flags defined here, need to be namespaced to the serverType other
// wise they potentially clash with other server types.
func init() {
flag.StringVar(&Port, serverType+".port", DefaultPort, "Default port")
caddy.RegisterServerType(serverType, caddy.ServerType{
Directives: func() []string { return directives },
DefaultInput: func() caddy.Input {
return caddy.CaddyfileInput{
Filepath: "Corefile",
Contents: []byte(".:" + Port + " {\nwhoami\n}\n"),
ServerTypeName: serverType,
}
},
NewContext: newContext,
})
}
func newContext() caddy.Context {
return &dnsContext{keysToConfigs: make(map[string]*Config)}
}
type dnsContext struct {
keysToConfigs map[string]*Config
// configs is the master list of all site configs.
configs []*Config
}
func (h *dnsContext) saveConfig(key string, cfg *Config) {
h.configs = append(h.configs, cfg)
h.keysToConfigs[key] = cfg
}
// InspectServerBlocks make sure that everything checks out before
// executing directives and otherwise prepares the directives to
// be parsed and executed.
func (h *dnsContext) InspectServerBlocks(sourceFile string, serverBlocks []caddyfile.ServerBlock) ([]caddyfile.ServerBlock, error) {
// Normalize and check all the zone names and check for duplicates
dups := map[string]string{}
for _, s := range serverBlocks {
for i, k := range s.Keys {
za, err := normalizeZone(k)
if err != nil {
return nil, err
}
s.Keys[i] = za.String()
if v, ok := dups[za.String()]; ok {
return nil, fmt.Errorf("cannot serve %s - zone already defined for %v", za, v)
}
dups[za.String()] = za.String()
// Save the config to our master list, and key it for lookups.
cfg := &Config{
Zone: za.Zone,
Port: za.Port,
Transport: za.Transport,
}
if za.IPNet == nil {
h.saveConfig(za.String(), cfg)
continue
}
ones, bits := za.IPNet.Mask.Size()
if (bits-ones)%8 != 0 { // only do this for non-octet bounderies
cfg.FilterFunc = func(s string) bool {
// TODO(miek): strings.ToLower! Slow and allocates new string.
addr := dnsutil.ExtractAddressFromReverse(strings.ToLower(s))
if addr == "" {
return true
}
return za.IPNet.Contains(net.ParseIP(addr))
}
}
h.saveConfig(za.String(), cfg)
}
}
return serverBlocks, nil
}
// MakeServers uses the newly-created siteConfigs to create and return a list of server instances.
func (h *dnsContext) MakeServers() ([]caddy.Server, error) {
// we must map (group) each config to a bind address
groups, err := groupConfigsByListenAddr(h.configs)
if err != nil {
return nil, err
}
// then we create a server for each group
var servers []caddy.Server
for addr, group := range groups {
// switch on addr
switch Transport(addr) {
case TransportDNS:
s, err := NewServer(addr, group)
if err != nil {
return nil, err
}
servers = append(servers, s)
case TransportTLS:
s, err := NewServerTLS(addr, group)
if err != nil {
return nil, err
}
servers = append(servers, s)
case TransportGRPC:
s, err := NewServergRPC(addr, group)
if err != nil {
return nil, err
}
servers = append(servers, s)
}
}
return servers, nil
}
// AddPlugin adds a plugin to a site's plugin stack.
func (c *Config) AddPlugin(m plugin.Plugin) {
c.Plugin = append(c.Plugin, m)
}
// registerHandler adds a handler to a site's handler registration. Handlers
// use this to announce that they exist to other plugin.
func (c *Config) registerHandler(h plugin.Handler) {
if c.registry == nil {
c.registry = make(map[string]plugin.Handler)
}
// Just overwrite...
c.registry[h.Name()] = h
}
// Handler returns the plugin handler that has been added to the config under its name.
// This is useful to inspect if a certain plugin is active in this server.
// Note that this is order dependent and the order is defined in directives.go, i.e. if your plugin
// comes before the plugin you are checking; it will not be there (yet).
func (c *Config) Handler(name string) plugin.Handler {
if c.registry == nil {
return nil
}
if h, ok := c.registry[name]; ok {
return h
}
return nil
}
// groupSiteConfigsByListenAddr groups site configs by their listen
// (bind) address, so sites that use the same listener can be served
// on the same server instance. The return value maps the listen
// address (what you pass into net.Listen) to the list of site configs.
// This function does NOT vet the configs to ensure they are compatible.
func groupConfigsByListenAddr(configs []*Config) (map[string][]*Config, error) {
groups := make(map[string][]*Config)
for _, conf := range configs {
addr, err := net.ResolveTCPAddr("tcp", net.JoinHostPort(conf.ListenHost, conf.Port))
if err != nil {
return nil, err
}
addrstr := conf.Transport + "://" + addr.String()
groups[addrstr] = append(groups[addrstr], conf)
}
return groups, nil
}
const (
// DefaultPort is the default port.
DefaultPort = "53"
// TLSPort is the default port for DNS-over-TLS.
TLSPort = "853"
// GRPCPort is the default port for DNS-over-gRPC.
GRPCPort = "443"
)
// These "soft defaults" are configurable by
// command line flags, etc.
var (
// Port is the port we listen on by default.
Port = DefaultPort
// GracefulTimeout is the maximum duration of a graceful shutdown.
GracefulTimeout time.Duration
)
var _ caddy.GracefulServer = new(Server)