dns: add settings dnstimeout/dnsmaxttl/dnsminttl

README.md

@@ -62,7 +62,7 @@ General:
 
 TODO:
 
-- [ ] IPv6 support
+- [ ] IPv6 support in ipset manager
 - [ ] Transparent UDP proxy (iptables tproxy)
 - [ ] Performance tuning
 - [ ] TUN/TAP device support

conf.go

@@ -17,7 +17,7 @@ var conf struct {
 	Verbose       bool
 	Strategy      string
 	CheckWebSite  string
-	CheckDuration int
+	CheckInterval int
 	Listen        []string
 	Forward       []string
 	RuleFile      []string
@@ -25,6 +25,9 @@ var conf struct {
 
 	DNS        string
 	DNSServer  []string
+	DNSTimeout int
+	DNSMaxTTL  int
+	DNSMinTTL  int
 	DNSRecord  []string
 
 	IPSet string
@@ -36,7 +39,7 @@ func confInit() {
 	flag.BoolVar(&conf.Verbose, "verbose", false, "verbose mode")
 	flag.StringVar(&conf.Strategy, "strategy", "rr", "forward strategy, default: rr")
 	flag.StringVar(&conf.CheckWebSite, "checkwebsite", "www.apple.com", "proxy check HTTP(NOT HTTPS) website address, format: HOST[:PORT], default port: 80")
-	flag.IntVar(&conf.CheckDuration, "checkduration", 30, "proxy check duration(seconds)")
+	flag.IntVar(&conf.CheckInterval, "checkduration", 30, "proxy check interval(seconds)")
 	flag.StringSliceUniqVar(&conf.Listen, "listen", nil, "listen url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS")
 	flag.StringSliceUniqVar(&conf.Forward, "forward", nil, "forward url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS[,SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS]")
 	flag.StringSliceUniqVar(&conf.RuleFile, "rulefile", nil, "rule file path")
@@ -44,6 +47,9 @@ func confInit() {
 
 	flag.StringVar(&conf.DNS, "dns", "", "dns forwarder server listen address")
 	flag.StringSliceUniqVar(&conf.DNSServer, "dnsserver", []string{"8.8.8.8:53"}, "remote dns server")
+	flag.IntVar(&conf.DNSTimeout, "dnstimeout", 3, "timeout value used in multiple dnsservers switch(seconds)")
+	flag.IntVar(&conf.DNSMaxTTL, "dnsmaxttl", 1800, "maximum TTL value for entries in the CACHE(seconds)")
+	flag.IntVar(&conf.DNSMinTTL, "dnsminttl", 0, "minimum TTL value for entries in the CACHE(seconds)")
 	flag.StringSliceUniqVar(&conf.DNSRecord, "dnsrecord", nil, "custom dns record, format: domain/ip")
 
 	flag.StringVar(&conf.IPSet, "ipset", "", "ipset name")
@@ -116,7 +122,7 @@ type RuleConf struct {
 	Forward       []string
 	Strategy      string
 	CheckWebSite  string
-	CheckDuration int
+	CheckInterval int
 
 	DNSServer []string
 	IPSet     string
@@ -134,7 +140,7 @@ func NewRuleConfFromFile(ruleFile string) (*RuleConf, error) {
 	f.StringSliceUniqVar(&p.Forward, "forward", nil, "forward url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS[,SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS]")
 	f.StringVar(&p.Strategy, "strategy", "rr", "forward strategy, default: rr")
 	f.StringVar(&p.CheckWebSite, "checkwebsite", "www.apple.com", "proxy check HTTP(NOT HTTPS) website address, format: HOST[:PORT], default port: 80")
-	f.IntVar(&p.CheckDuration, "checkduration", 30, "proxy check duration(seconds)")
+	f.IntVar(&p.CheckInterval, "checkduration", 30, "proxy check interval(seconds)")
 
 	f.StringSliceUniqVar(&p.DNSServer, "dnsserver", nil, "remote dns server")
 	f.StringVar(&p.IPSet, "ipset", "", "ipset name")

config/glider.conf.example

@@ -125,6 +125,12 @@ dns=:53
 # global remote dns server (you can specify different dns server in rule file)
 dnsserver=8.8.8.8:53
 dnsserver=1.1.1.1:53
+# timeout value used in multiple dnsservers switch(seconds)
+dnstimeout=3
+# maximum TTL value for entries in the CACHE(seconds)
+dnsmaxttl=1800
+# minimum TTL value for entries in the CACHE(seconds)
+dnsminttl=0
 # custom records
 dnsrecord=www.example.com/1.2.3.4
 dnsrecord=www.example.com/2606:2800:220:1:248:1893:25c8:1946

dns/client.go

@@ -13,26 +13,32 @@ import (
 	"github.com/nadoo/glider/proxy"
 )
 
-// DefaultTTL is default ttl in seconds
-const DefaultTTL = 600
-
 // HandleFunc function handles the dns TypeA or TypeAAAA answer
 type HandleFunc func(Domain, ip string) error
 
+// Config for dns
+type Config struct {
+	Timeout int
+	MaxTTL  int
+	MinTTL  int
+}
+
 // Client is a dns client struct
 type Client struct {
 	dialer      proxy.Dialer
 	cache       *Cache
+	config      *Config
 	upServers   []string
 	upServerMap map[string][]string
 	handlers    []HandleFunc
 }
 
 // NewClient returns a new dns client
-func NewClient(dialer proxy.Dialer, upServers []string) (*Client, error) {
+func NewClient(dialer proxy.Dialer, upServers []string, config *Config) (*Client, error) {
 	c := &Client{
 		dialer:      dialer,
 		cache:       NewCache(),
+		config:      config,
 		upServers:   upServers,
 		upServerMap: make(map[string][]string),
 	}
@@ -75,7 +81,7 @@ func (c *Client) Exchange(reqBytes []byte, clientAddr string, preferTCP bool) ([
 		return respBytes, err
 	}
 
-	ttl := DefaultTTL
+	ttl := c.config.MinTTL
 	ips := []string{}
 	for _, answer := range resp.Answers {
 		if answer.TYPE == QTypeA || answer.TYPE == QTypeAAAA {
@@ -85,14 +91,18 @@ func (c *Client) Exchange(reqBytes []byte, clientAddr string, preferTCP bool) ([
 			if answer.IP != "" {
 				ips = append(ips, answer.IP)
 			}
-			if answer.TTL != 0 {
 			ttl = int(answer.TTL)
 		}
 	}
+
+	if ttl > c.config.MaxTTL {
+		ttl = c.config.MaxTTL
+	} else if ttl < c.config.MinTTL {
+		ttl = c.config.MinTTL
 	}
 
 	// add to cache only when there's a valid ip address
-	if len(ips) != 0 {
+	if len(ips) != 0 && ttl > 0 {
 		c.cache.Put(getKey(resp.Question), respBytes, ttl)
 	}
 
@@ -113,9 +123,9 @@ func (c *Client) exchange(qname string, reqBytes []byte, preferTCP bool) (server
 		network = "udp"
 	}
 
-	var rc net.Conn
 	servers := c.GetServers(qname)
 	for _, server = range servers {
+		var rc net.Conn
 		rc, err = dialer.Dial(network, server)
 		if err != nil {
 			log.F("[dns] failed to connect to server %v: %v", server, err)
@@ -125,7 +135,7 @@ func (c *Client) exchange(qname string, reqBytes []byte, preferTCP bool) (server
 
 		// TODO: support timeout setting for different upstream server
 		if len(servers) > 1 {
-			rc.SetDeadline(time.Now().Add(time.Duration(3) * time.Second))
+			rc.SetDeadline(time.Now().Add(time.Duration(c.config.Timeout) * time.Second))
 		}
 
 		switch network {

dns/server.go

@@ -21,8 +21,8 @@ type Server struct {
 }
 
 // NewServer returns a new dns server
-func NewServer(addr string, dialer proxy.Dialer, upServers []string) (*Server, error) {
+func NewServer(addr string, dialer proxy.Dialer, upServers []string, config *Config) (*Server, error) {
-	c, err := NewClient(dialer, upServers)
+	c, err := NewClient(dialer, upServers, config)
 	s := &Server{
 		addr:   addr,
 		Client: c,

main.go

@@ -42,7 +42,7 @@ func dialerFromConf() proxy.Dialer {
 		fwdrs = append(fwdrs, fwdr)
 	}
 
-	return NewStrategyDialer(conf.Strategy, fwdrs, conf.CheckWebSite, conf.CheckDuration)
+	return NewStrategyDialer(conf.Strategy, fwdrs, conf.CheckWebSite, conf.CheckInterval)
 }
 
 func main() {
@@ -57,7 +57,13 @@ func main() {
 	dialer := NewRuleDialer(conf.rules, dialerFromConf())
 	ipsetM, _ := NewIPSetManager(conf.IPSet, conf.rules)
 	if conf.DNS != "" {
-		d, err := dns.NewServer(conf.DNS, dialer, conf.DNSServer)
+
+		dnscfg := &dns.Config{
+			Timeout: conf.DNSTimeout,
+			MaxTTL:  conf.DNSMaxTTL,
+			MinTTL:  conf.DNSMinTTL}
+
+		d, err := dns.NewServer(conf.DNS, dialer, conf.DNSServer, dnscfg)
 		if err != nil {
 			log.Fatal(err)
 		}

rule.go

@@ -36,7 +36,7 @@ func NewRuleDialer(rules []*RuleConf, gDialer proxy.Dialer) *RuleDialer {
 			fwdrs = append(fwdrs, fwdr)
 		}
 
-		sDialer := NewStrategyDialer(r.Strategy, fwdrs, r.CheckWebSite, r.CheckDuration)
+		sDialer := NewStrategyDialer(r.Strategy, fwdrs, r.CheckWebSite, r.CheckInterval)
 
 		for _, domain := range r.Domain {
 			rd.domainMap.Store(strings.ToLower(domain), sDialer)