From 6713bba6bdf63cfbee08a894f2e01a2cea2ce7c4 Mon Sep 17 00:00:00 2001
From: hiddify <hiddify@gmail.com>
Date: Tue, 30 Jan 2024 10:36:21 +0100
Subject: [PATCH] new: add static dns entries

---
 option/dns.go       | 11 +++----
 route/router.go     |  2 ++
 route/router_dns.go |  8 +++--
 route/staticDNS.go  | 73 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 87 insertions(+), 7 deletions(-)
 create mode 100644 route/staticDNS.go

diff --git a/option/dns.go b/option/dns.go
index e0d237b7d3..4f196fa8a1 100644
--- a/option/dns.go
+++ b/option/dns.go
@@ -3,11 +3,12 @@ package option
 import "net/netip"
 
 type DNSOptions struct {
-	Servers        []DNSServerOptions `json:"servers,omitempty"`
-	Rules          []DNSRule          `json:"rules,omitempty"`
-	Final          string             `json:"final,omitempty"`
-	ReverseMapping bool               `json:"reverse_mapping,omitempty"`
-	FakeIP         *DNSFakeIPOptions  `json:"fakeip,omitempty"`
+	Servers        []DNSServerOptions  `json:"servers,omitempty"`
+	Rules          []DNSRule           `json:"rules,omitempty"`
+	Final          string              `json:"final,omitempty"`
+	ReverseMapping bool                `json:"reverse_mapping,omitempty"`
+	FakeIP         *DNSFakeIPOptions   `json:"fakeip,omitempty"`
+	StaticIPs      map[string][]string `json:"static_ips,omitempty"`
 	DNSClientOptions
 }
 
diff --git a/route/router.go b/route/router.go
index adbdbd2082..8e70a0f294 100644
--- a/route/router.go
+++ b/route/router.go
@@ -70,6 +70,7 @@ type Router struct {
 	dnsClient                          *dns.Client
 	defaultDomainStrategy              dns.DomainStrategy
 	dnsRules                           []adapter.DNSRule
+	staticDns                          map[string]StaticDNSEntry //Hiddify
 	ruleSets                           []adapter.RuleSet
 	ruleSetMap                         map[string]adapter.RuleSet
 	defaultTransport                   dns.Transport
@@ -131,6 +132,7 @@ func NewRouter(
 		needPackageManager: C.IsAndroid && platformInterface == nil && common.Any(inbounds, func(inbound option.Inbound) bool {
 			return len(inbound.TunOptions.IncludePackage) > 0 || len(inbound.TunOptions.ExcludePackage) > 0
 		}),
+		staticDns: createEntries(dnsOptions.StaticIPs),//hiddify
 	}
 	router.dnsClient = dns.NewClient(dns.ClientOptions{
 		DisableCache:     dnsOptions.DNSClientOptions.DisableCache,
diff --git a/route/router_dns.go b/route/router_dns.go
index 8ae9171002..e276a4eda3 100644
--- a/route/router_dns.go
+++ b/route/router_dns.go
@@ -9,7 +9,7 @@ import (
 	"github.com/sagernet/sing-box/adapter"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/log"
-	"github.com/sagernet/sing-dns"
+	dns "github.com/sagernet/sing-dns"
 	"github.com/sagernet/sing/common/cache"
 	E "github.com/sagernet/sing/common/exceptions"
 	F "github.com/sagernet/sing/common/format"
@@ -131,7 +131,11 @@ func (r *Router) Lookup(ctx context.Context, domain string, strategy dns.DomainS
 	}
 	ctx, cancel := context.WithTimeout(ctx, C.DNSTimeout)
 	defer cancel()
-	addrs, err := r.dnsClient.Lookup(ctx, transport, domain, strategy)
+
+	addrs, err := lookupStaticIP(domain, strategy, r.staticDns)
+	if addrs == nil || err != nil {
+		addrs, err = r.dnsClient.Lookup(ctx, transport, domain, strategy)
+	}
 	if len(addrs) > 0 {
 		r.dnsLogger.InfoContext(ctx, "lookup succeed for ", domain, ": ", strings.Join(F.MapToString(addrs), " "))
 	} else if err != nil {
diff --git a/route/staticDNS.go b/route/staticDNS.go
new file mode 100644
index 0000000000..6f92a8f1a6
--- /dev/null
+++ b/route/staticDNS.go
@@ -0,0 +1,73 @@
+package route
+
+import (
+	"fmt"
+	"net/netip"
+
+	dns "github.com/sagernet/sing-dns"
+)
+
+type StaticDNSEntry struct {
+	IPv4 *netip.Addr
+	IPv6 *netip.Addr
+}
+
+func createEntries(items map[string][]string) map[string]StaticDNSEntry {
+	entries := make(map[string]StaticDNSEntry)
+
+	for domain, ips := range items {
+		entry := StaticDNSEntry{}
+
+		for _, ipString := range ips {
+			ip, err := netip.ParseAddr(ipString)
+			if err != nil {
+				fmt.Printf("Invalid IP address for domain %s: %s\n", domain, ipString)
+				continue
+			}
+
+			if ip.Is4() {
+				entry.IPv4 = &ip
+			} else {
+				entry.IPv6 = &ip
+			}
+		}
+		entries[domain] = entry
+	}
+
+	return entries
+}
+
+func lookupStaticIP(domain string, strategy uint8, entries map[string]StaticDNSEntry) ([]netip.Addr, error) {
+
+	if staticDns, ok := entries[domain]; ok {
+		addrs := []netip.Addr{}
+		switch strategy {
+		case dns.DomainStrategyUseIPv4:
+			if staticDns.IPv4 != nil {
+				addrs = append(addrs, *staticDns.IPv4)
+			}
+		case dns.DomainStrategyUseIPv6:
+			if staticDns.IPv6 != nil {
+				addrs = append(addrs, *staticDns.IPv6)
+			}
+		case dns.DomainStrategyPreferIPv6:
+			if staticDns.IPv6 != nil {
+				addrs = append(addrs, *staticDns.IPv6)
+			}
+			if staticDns.IPv4 != nil {
+				addrs = append(addrs, *staticDns.IPv4)
+			}
+		default:
+			if staticDns.IPv4 != nil {
+				addrs = append(addrs, *staticDns.IPv4)
+			}
+			if staticDns.IPv6 != nil {
+				addrs = append(addrs, *staticDns.IPv6)
+			}
+		}
+		return addrs, nil
+	} else {
+		return nil, fmt.Errorf("NotFound")
+	}
+
+}