Support routing by time and weekday (#167)

* Support routing by time and weekday

* Add note about impossible routes

README.md

@@ -15,7 +15,7 @@ Features:
 - Support for plain DNS, UDP and TCP for incoming and outgoing requests
 - Connection reuse and pipelining queries for efficiency
 - Multiple failover and load-balancing algorithms, caching, in-line query/response modification and translation (full list [here](doc/configuration.md))
-- Routing of queries based on query type, query name, or client IP
+- Routing of queries based on query type, class, query name, time, or client IP
 - EDNS0 query and response padding ([RFC7830](https://tools.ietf.org/html/rfc7830), [RFC8467](https://tools.ietf.org/html/rfc8467))
 - EDNS0 Client Subnet (ECS) manipulation ([RFC7871](https://tools.ietf.org/html/rfc7871))
 - Support for bootstrap addresses to avoid the initial service name lookup
@@ -24,7 +24,7 @@ Features:
 
 ## Installation
 
-Install [Go](https://golang.org/dl) version 1.13+ then run the following to build the binary. It'll be placed in $HOME/go/bin by default:
+Install [Go](https://golang.org/dl) version 1.15+ then run the following to build the binary. It'll be placed in $HOME/go/bin by default:
 
 ```text
 GO111MODULE=on go get -v github.com/folbricht/routedns/cmd/routedns

cmd/routedns/config.go

@@ -123,13 +123,15 @@ type router struct {
 }
 
 type route struct {
-	Type     string // Deprecated, use "Types" instead
+	Type          string // Deprecated, use "Types" instead
-	Types    []string
+	Types         []string
-	Class    string
+	Class         string
-	Name     string
+	Name          string
-	Source   string
+	Source        string
-	Invert   bool // Invert the result of the match
+	Weekdays      []string // 'mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'
-	Resolver string
+	After, Before string   // Hour:Minute in 24h format, for example "14:30"
+	Invert        bool     // Invert the result of the match
+	Resolver      string
 }
 
 // LoadConfig reads a config file and returns the decoded structure.

cmd/routedns/example-config/router-time.toml

@@ -0,0 +1,20 @@
+# Routing traffic based on time of day and a weekday.
+
+[listeners.local-udp]
+address = "127.0.0.1:53"
+protocol = "udp"
+resolver = "router1"
+
+[routers.router1]
+routes = [
+  { name = '(^|\.)twitter\.com\.$', weekdays = ["sat", "sun"], after = "09:00", before = "17:00", resolver="static-nxdomain" }, # No Twitter on weekends from 9am-5pm!
+  { resolver="cloudflare-dot" }, # default route
+]
+
+[groups.static-nxdomain]
+type  = "static-responder"
+rcode = 3
+
+[resolvers.cloudflare-dot]
+address = "1.1.1.1:853"
+protocol = "dot"

cmd/routedns/main.go

@@ -603,7 +603,7 @@ func instantiateRouter(id string, r router, resolvers map[string]rdns.Resolver)
 		if route.Type != "" { // Support the deprecated "Type" by just adding it to "Types" if defined
 			types = append(types, route.Type)
 		}
-		r, err := rdns.NewRoute(route.Name, route.Class, types, route.Source, resolver)
+		r, err := rdns.NewRoute(route.Name, route.Class, types, route.Weekdays, route.Before, route.After, route.Source, resolver)
 		if err != nil {
 			return fmt.Errorf("failure parsing routes for router '%s' : %s", id, err.Error())
 		}

doc/configuration.md

@@ -991,7 +991,7 @@ Example config files: [response-collapse.toml](../cmd/routedns/example-config/re
 
 ### Router
 
-Routers are used to direct queries to specific upstream resolvers, modifier, or to other routers based on the query type, name, or client information. Each router contains at least one route. Routes are are evaluated in the order they are defined and the first match will be used. Routes that match on the query name are regular expressions. Typically the last route should not have a class, type or name, making it the default route.
+Routers are used to direct queries to specific upstream resolvers, modifiers, or to other routers based on the query type, name, time of day, or client information. Each router contains at least one route. Routes are are evaluated in the order they are defined and the first match will be used. Routes that match on the query name are regular expressions. Typically the last route should not have a class, type or name, making it the default route.
 
 #### Configuration
 
@@ -1008,6 +1008,9 @@ A route has the following fields:
 - `class` - If defined, only matches queries of this class (`IN`, `CH`, `HS`, `NONE`, `ANY`). Optional.
 - `name` - A regular expression that is applied to the query name. Note that dots in domain names need to be escaped. Optional.
 - `source` - Network in CIDR notation. Used to route based on client IP. Optional.
+- `weekdays` - List of weekdays this route should match on. Possible values: `mon`, `tue`, `wed`, `thu`, `fri`, `sat`, `sun`. Uses local time, not UTC.
+- `after` - Time of day in the format HH:mm after which the rule matches. Uses 24h format. For example `09:00`. Note that together with the `before` parameter it is possible to accidentally write routes that can never trigger. For example `after=12:00 before=11:00` can never match as both conditions have to be met for the route to be used.
+- `before` - Time of day in the format HH:mm before which the rule matches. Uses 24h format. For example `17:30`.
 - `invert` - Invert the result of the matching if set to `true`. Optional.
 - `resolver` - The identifier of a resolver, group, or another router. Required.
 
@@ -1057,7 +1060,17 @@ type  = "static-responder"
 rcode = 3
 ```
 
-Example config files: [split-dns.toml](../cmd/routedns/example-config/split-dns.toml), [block-split-cache.toml](../cmd/routedns/example-config/block-split-cache.toml), [family-browsing.toml](../cmd/routedns/example-config/family-browsing.toml), [walled-garden.toml](../cmd/routedns/example-config/walled-garden.toml), [router.toml](../cmd/routedns/example-config/router.toml)
+Use a different upstream resolver on weekends between 9am and 5pm.
+
+```toml
+[routers.router1]
+routes = [
+  { weekdays = ["sat", "sun"], after = "09:00", before = "17:00", resolver="google-dot" },
+  { resolver="cloudflare-dot" },
+]
+```
+
+Example config files: [split-dns.toml](../cmd/routedns/example-config/split-dns.toml), [block-split-cache.toml](../cmd/routedns/example-config/block-split-cache.toml), [family-browsing.toml](../cmd/routedns/example-config/family-browsing.toml), [walled-garden.toml](../cmd/routedns/example-config/walled-garden.toml), [router.toml](../cmd/routedns/example-config/router.toml), [router-time.toml](../cmd/routedns/example-config/router-time.toml)
 
 ### Rate Limiter
 

example_test.go

@@ -44,8 +44,8 @@ func Example_router() {
 
 	// Build a router that will send all "*.cloudflare.com" to the cloudflare
 	// resolver while everything else goes to the google resolver (default)
-	route1, _ := rdns.NewRoute(`\.cloudflare\.com\.$`, "", nil, "", cloudflare)
+	route1, _ := rdns.NewRoute(`\.cloudflare\.com\.$`, "", nil, nil, "", "", "", cloudflare)
-	route2, _ := rdns.NewRoute("", "", nil, "", google)
+	route2, _ := rdns.NewRoute("", "", nil, nil, "", "", "", google)
 	r := rdns.NewRouter("my-router")
 	r.Add(route1, route2)
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/folbricht/routedns
 
-go 1.12
+go 1.15
 
 require (
 	github.com/BurntSushi/toml v0.3.1

route.go

@@ -5,7 +5,9 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/miekg/dns"
 )
@@ -15,12 +17,15 @@ type route struct {
 	class    uint16
 	name     *regexp.Regexp
 	source   *net.IPNet
+	weekdays []time.Weekday
+	before   *TimeOfDay
+	after    *TimeOfDay
 	inverted bool // invert the matching behavior
 	resolver Resolver
 }
 
 // NewRoute initializes a route from string parameters.
-func NewRoute(name, class string, types []string, source string, resolver Resolver) (*route, error) {
+func NewRoute(name, class string, types, weekdays []string, before, after, source string, resolver Resolver) (*route, error) {
 	if resolver == nil {
 		return nil, errors.New("no resolver defined for route")
 	}
@@ -28,6 +33,18 @@ func NewRoute(name, class string, types []string, source string, resolver Resolv
 	if err != nil {
 		return nil, err
 	}
+	w, err := stringsToWeekdays(weekdays)
+	if err != nil {
+		return nil, err
+	}
+	b, err := parseTimeOfDay(before)
+	if err != nil {
+		return nil, err
+	}
+	a, err := parseTimeOfDay(after)
+	if err != nil {
+		return nil, err
+	}
 	c, err := stringToClass(class)
 	if err != nil {
 		return nil, err
@@ -47,6 +64,9 @@ func NewRoute(name, class string, types []string, source string, resolver Resolv
 		types:    t,
 		class:    c,
 		name:     re,
+		weekdays: w,
+		before:   b,
+		after:    a,
 		source:   sNet,
 		resolver: resolver,
 	}, nil
@@ -66,6 +86,30 @@ func (r *route) match(q *dns.Msg, ci ClientInfo) bool {
 	if r.source != nil && !r.source.Contains(ci.SourceIP) {
 		return r.inverted
 	}
+	if len(r.weekdays) > 0 || r.before != nil || r.after != nil {
+		now := time.Now().Local()
+		hour := now.Hour()
+		minute := now.Minute()
+		if len(r.weekdays) > 0 {
+			weekday := now.Weekday()
+			var weekdayMatch bool
+			for _, wd := range r.weekdays {
+				if weekday == wd {
+					weekdayMatch = true
+					break
+				}
+			}
+			if !weekdayMatch {
+				return r.inverted
+			}
+		}
+		if r.before != nil && !r.before.isAfter(hour, minute) {
+			return r.inverted
+		}
+		if r.after != nil && !r.after.isBefore(hour, minute) {
+			return r.inverted
+		}
+	}
 	return !r.inverted
 }
 
@@ -134,3 +178,64 @@ func stringToClass(s string) (uint16, error) {
 		return 0, fmt.Errorf("unknown class '%s'", s)
 	}
 }
+
+func stringsToWeekdays(weekdays []string) ([]time.Weekday, error) {
+	var result []time.Weekday
+	for _, day := range weekdays {
+		var weekday time.Weekday
+		switch day {
+		case "mon":
+			weekday = time.Monday
+		case "tue":
+			weekday = time.Tuesday
+		case "wed":
+			weekday = time.Wednesday
+		case "thu":
+			weekday = time.Thursday
+		case "fri":
+			weekday = time.Friday
+		case "sat":
+			weekday = time.Saturday
+		case "sun":
+			weekday = time.Sunday
+		default:
+			return nil, fmt.Errorf("unrecognized weekday %q, must be 'mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'", day)
+		}
+		result = append(result, weekday)
+	}
+	return result, nil
+}
+
+type TimeOfDay struct {
+	hour, minute int
+}
+
+func parseTimeOfDay(t string) (*TimeOfDay, error) {
+	if t == "" {
+		return nil, nil
+	}
+	f := strings.SplitN(t, ":", 2)
+	hour, err := strconv.Atoi(f[0])
+	if err != nil {
+		return nil, err
+	}
+	var min int
+	if len(f) > 1 {
+		min, err = strconv.Atoi(f[1])
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &TimeOfDay{
+		hour:   hour,
+		minute: min,
+	}, nil
+}
+
+func (t *TimeOfDay) isBefore(hour, minute int) bool {
+	return t.hour < hour || (t.hour == hour && t.minute <= minute)
+}
+
+func (t *TimeOfDay) isAfter(hour, minute int) bool {
+	return t.hour > hour || (t.hour == hour && t.minute > minute)
+}

route_test.go

@@ -79,7 +79,7 @@ func TestRoute(t *testing.T) {
 		},
 	}
 	for _, test := range tests {
-		r, err := NewRoute(test.rName, test.rClass, test.rType, "", &TestResolver{})
+		r, err := NewRoute(test.rName, test.rClass, test.rType, nil, "", "", "", &TestResolver{})
 		require.NoError(t, err)
 		r.Invert(test.rInvert)
 

router_test.go

@@ -14,8 +14,8 @@ func TestRouterType(t *testing.T) {
 	q := new(dns.Msg)
 	var ci ClientInfo
 
-	route1, _ := NewRoute("", "", []string{"MX"}, "", r1)
+	route1, _ := NewRoute("", "", []string{"MX"}, nil, "", "", "", r1)
-	route2, _ := NewRoute("", "", nil, "", r2)
+	route2, _ := NewRoute("", "", nil, nil, "", "", "", r2)
 
 	router := NewRouter("my-router")
 	router.Add(route1, route2)
@@ -41,8 +41,8 @@ func TestRouterClass(t *testing.T) {
 	q := new(dns.Msg)
 	var ci ClientInfo
 
-	route1, _ := NewRoute("", "ANY", nil, "", r1)
+	route1, _ := NewRoute("", "ANY", nil, nil, "", "", "", r1)
-	route2, _ := NewRoute("", "", nil, "", r2)
+	route2, _ := NewRoute("", "", nil, nil, "", "", "", r2)
 
 	router := NewRouter("my-router")
 	router.Add(route1, route2)
@@ -69,8 +69,8 @@ func TestRouterName(t *testing.T) {
 	q := new(dns.Msg)
 	var ci ClientInfo
 
-	route1, _ := NewRoute(`\.acme\.test\.$`, "", nil, "", r1)
+	route1, _ := NewRoute(`\.acme\.test\.$`, "", nil, nil, "", "", "", r1)
-	route2, _ := NewRoute("", "", nil, "", r2)
+	route2, _ := NewRoute("", "", nil, nil, "", "", "", r2)
 
 	router := NewRouter("my-router")
 	router.Add(route1, route2)
@@ -96,8 +96,8 @@ func TestRouterSource(t *testing.T) {
 	q := new(dns.Msg)
 	q.SetQuestion("acme.test.", dns.TypeA)
 
-	route1, _ := NewRoute("", "", nil, "192.168.1.100/32", r1)
+	route1, _ := NewRoute("", "", nil, nil, "", "", "192.168.1.100/32", r1)
-	route2, _ := NewRoute("", "", nil, "", r2)
+	route2, _ := NewRoute("", "", nil, nil, "", "", "", r2)
 
 	router := NewRouter("my-router")
 	router.Add(route1, route2)