+ use per-client DNS servers

AGHTechDoc.md

@@ -669,6 +669,7 @@ Response:
 				key: "value"
 				...
 			}
+			upstreams: ["upstream1", ...]
 		}
 	]
 	auto_clients: [
@@ -703,6 +704,7 @@ Request:
 		safesearch_enabled: false
 		use_global_blocked_services: true
 		blocked_services: [ "name1", ... ]
+		upstreams: ["upstream1", ...]
 	}
 
 Response:
@@ -732,6 +734,7 @@ Request:
 			safesearch_enabled: false
 			use_global_blocked_services: true
 			blocked_services: [ "name1", ... ]
+			upstreams: ["upstream1", ...]
 		}
 	}
 

dnsforward/dnsforward.go

@@ -94,6 +94,9 @@ type FilteringConfig struct {
 	// Filtering callback function
 	FilterHandler func(clientAddr string, settings *dnsfilter.RequestFilteringSettings) `yaml:"-"`
 
+	// This callback function returns the list of upstream servers for a client specified by IP address
+	GetUpstreamsByClient func(clientAddr string) []string `yaml:"-"`
+
 	ProtectionEnabled bool `yaml:"protection_enabled"` // whether or not use any of dnsfilter features
 
 	BlockingMode       string   `yaml:"blocking_mode"`        // mode how to answer filtered requests
@@ -393,6 +396,19 @@ func (s *Server) handleDNSRequest(p *proxy.Proxy, d *proxy.DNSContext) error {
 			d.Req.Question[0].Name = dns.Fqdn(res.CanonName)
 		}
 
+		if d.Addr != nil && s.conf.GetUpstreamsByClient != nil {
+			clientIP, _, _ := net.SplitHostPort(d.Addr.String())
+			upstreams := s.conf.GetUpstreamsByClient(clientIP)
+			for _, us := range upstreams {
+				u, err := upstream.AddressToUpstream(us, upstream.Options{Timeout: 30 * time.Second})
+				if err != nil {
+					log.Error("upstream.AddressToUpstream: %s: %s", us, err)
+					continue
+				}
+				d.Upstreams = append(d.Upstreams, u)
+			}
+		}
+
 		// request was not filtered so let it be processed further
 		err = p.Resolve(d)
 		if err != nil {

dnsforward/dnsforward_http.go

@@ -44,7 +44,7 @@ func (s *Server) handleSetUpstreamConfig(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	err = validateUpstreams(req.Upstreams)
+	err = ValidateUpstreams(req.Upstreams)
 	if err != nil {
 		httpError(r, w, http.StatusBadRequest, "wrong upstreams specification: %s", err)
 		return
@@ -78,8 +78,8 @@ func (s *Server) handleSetUpstreamConfig(w http.ResponseWriter, r *http.Request)
 	}
 }
 
-// validateUpstreams validates each upstream and returns an error if any upstream is invalid or if there are no default upstreams specified
+// ValidateUpstreams validates each upstream and returns an error if any upstream is invalid or if there are no default upstreams specified
-func validateUpstreams(upstreams []string) error {
+func ValidateUpstreams(upstreams []string) error {
 	var defaultUpstreamFound bool
 	for _, u := range upstreams {
 		d, err := validateUpstream(u)

dnsforward/dnsforward_test.go

@@ -762,21 +762,21 @@ func TestValidateUpstreamsSet(t *testing.T) {
 		"[/host.com/google.com/]8.8.8.8",
 		"[/host/]sdns://AQMAAAAAAAAAFDE3Ni4xMDMuMTMwLjEzMDo1NDQzINErR_JS3PLCu_iZEIbq95zkSV2LFsigxDIuUso_OQhzIjIuZG5zY3J5cHQuZGVmYXVsdC5uczEuYWRndWFyZC5jb20",
 	}
-	err := validateUpstreams(upstreamsSet)
+	err := ValidateUpstreams(upstreamsSet)
 	if err == nil {
 		t.Fatalf("there is no default upstream")
 	}
 
 	// Let's add default upstream
 	upstreamsSet = append(upstreamsSet, "8.8.8.8")
-	err = validateUpstreams(upstreamsSet)
+	err = ValidateUpstreams(upstreamsSet)
 	if err != nil {
 		t.Fatalf("upstreams set is valid, but doesn't pass through validation cause: %s", err)
 	}
 
 	// Let's add invalid upstream
 	upstreamsSet = append(upstreamsSet, "dhcp://fake.dns")
-	err = validateUpstreams(upstreamsSet)
+	err = ValidateUpstreams(upstreamsSet)
 	if err == nil {
 		t.Fatalf("there is an invalid upstream in set, but it pass through validation")
 	}

home/clients.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/dhcpd"
+	"github.com/AdguardTeam/AdGuardHome/dnsforward"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/utils"
 )
@@ -34,6 +35,8 @@ type Client struct {
 
 	UseOwnBlockedServices bool // false: use global settings
 	BlockedServices       []string
+
+	Upstreams []string // list of upstream servers to be used for the client's requests
 }
 
 type clientSource uint
@@ -96,6 +99,8 @@ type clientObject struct {
 
 	UseGlobalBlockedServices bool     `yaml:"use_global_blocked_services"`
 	BlockedServices          []string `yaml:"blocked_services"`
+
+	Upstreams []string `yaml:"upstreams"`
 }
 
 func (clients *clientsContainer) addFromConfig(objects []clientObject) {
@@ -111,6 +116,8 @@ func (clients *clientsContainer) addFromConfig(objects []clientObject) {
 
 			UseOwnBlockedServices: !cy.UseGlobalBlockedServices,
 			BlockedServices:       cy.BlockedServices,
+
+			Upstreams: cy.Upstreams,
 		}
 		_, err := clients.Add(cli)
 		if err != nil {
@@ -134,6 +141,8 @@ func (clients *clientsContainer) WriteDiskConfig(objects *[]clientObject) {
 
 			UseGlobalBlockedServices: !cli.UseOwnBlockedServices,
 			BlockedServices:          cli.BlockedServices,
+
+			Upstreams: cli.Upstreams,
 		}
 		*objects = append(*objects, cy)
 	}
@@ -268,6 +277,14 @@ func (c *Client) check() error {
 
 		return fmt.Errorf("Invalid ID: %s", id)
 	}
+
+	if len(c.Upstreams) != 0 {
+		err := dnsforward.ValidateUpstreams(c.Upstreams)
+		if err != nil {
+			return fmt.Errorf("Invalid upstream servers: %s", err)
+		}
+	}
+
 	return nil
 }
 

home/clients_http.go

@@ -20,6 +20,8 @@ type clientJSON struct {
 
 	UseGlobalBlockedServices bool     `json:"use_global_blocked_services"`
 	BlockedServices          []string `json:"blocked_services"`
+
+	Upstreams []string `json:"upstreams"`
 }
 
 type clientHostJSON struct {
@@ -92,6 +94,8 @@ func jsonToClient(cj clientJSON) (*Client, error) {
 
 		UseOwnBlockedServices: !cj.UseGlobalBlockedServices,
 		BlockedServices:       cj.BlockedServices,
+
+		Upstreams: cj.Upstreams,
 	}
 	return &c, nil
 }
@@ -109,6 +113,8 @@ func clientToJSON(c *Client) clientJSON {
 
 		UseGlobalBlockedServices: !c.UseOwnBlockedServices,
 		BlockedServices:          c.BlockedServices,
+
+		Upstreams: c.Upstreams,
 	}
 
 	cj.WhoisInfo = make(map[string]interface{})

home/dns.go

@@ -170,9 +170,19 @@ func generateServerConfig() (dnsforward.ServerConfig, error) {
 	}
 
 	newconfig.FilterHandler = applyAdditionalFiltering
+	newconfig.GetUpstreamsByClient = getUpstreamsByClient
 	return newconfig, nil
 }
 
+func getUpstreamsByClient(clientAddr string) []string {
+	c, ok := config.clients.Find(clientAddr)
+	if !ok {
+		return []string{}
+	}
+	log.Debug("Using upstreams %v for client %s (IP: %s)", c.Upstreams, c.Name, clientAddr)
+	return c.Upstreams
+}
+
 // If a client has his own settings, apply them
 func applyAdditionalFiltering(clientAddr string, setts *dnsfilter.RequestFilteringSettings) {