From 1908d02db0637cc32ff360603197a31c847c7a4a Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Mon, 17 Jul 2023 10:33:20 +0800
Subject: [PATCH] feat: Add Meta-geoip V0 database support

---
 component/mmdb/mmdb.go   | 21 +++++++++++++++------
 component/mmdb/reader.go | 26 +++++++++++++++++++++++---
 constant/path.go         |  3 ++-
 dns/filters.go           |  9 +++++++--
 rules/common/geoip.go    |  9 +++++++--
 5 files changed, 54 insertions(+), 14 deletions(-)

diff --git a/component/mmdb/mmdb.go b/component/mmdb/mmdb.go
index 16d4d2df..5db8bee9 100644
--- a/component/mmdb/mmdb.go
+++ b/component/mmdb/mmdb.go
@@ -20,6 +20,7 @@ type databaseType = uint8
 const (
 	typeMaxmind databaseType = iota
 	typeSing
+	typeMetaV0
 )
 
 var (
@@ -34,9 +35,12 @@ func LoadFromBytes(buffer []byte) {
 			log.Fatalln("Can't load mmdb: %s", err.Error())
 		}
 		reader = Reader{Reader: mmdb}
-		if mmdb.Metadata.DatabaseType == "sing-geoip" {
+		switch mmdb.Metadata.DatabaseType {
+		case "sing-geoip":
 			reader.databaseType = typeSing
-		} else {
+		case "Meta-geoip0":
+			reader.databaseType = typeMetaV0
+		default:
 			reader.databaseType = typeMaxmind
 		}
 	})
@@ -52,14 +56,19 @@ func Verify() bool {
 
 func Instance() Reader {
 	once.Do(func() {
-		mmdb, err := maxminddb.Open(C.Path.MMDB())
+		mmdbPath := C.Path.MMDB()
+		log.Debugln("Load MMDB file: %s", mmdbPath)
+		mmdb, err := maxminddb.Open(mmdbPath)
 		if err != nil {
-			log.Fatalln("Can't load mmdb: %s", err.Error())
+			log.Fatalln("Can't load MMDB: %s", err.Error())
 		}
 		reader = Reader{Reader: mmdb}
-		if mmdb.Metadata.DatabaseType == "sing-geoip" {
+		switch mmdb.Metadata.DatabaseType {
+		case "sing-geoip":
 			reader.databaseType = typeSing
-		} else {
+		case "Meta-geoip0":
+			reader.databaseType = typeMetaV0
+		default:
 			reader.databaseType = typeMaxmind
 		}
 	})
diff --git a/component/mmdb/reader.go b/component/mmdb/reader.go
index 35040344..4db53d4f 100644
--- a/component/mmdb/reader.go
+++ b/component/mmdb/reader.go
@@ -5,6 +5,7 @@ import (
 	"net"
 
 	"github.com/oschwald/maxminddb-golang"
+	"github.com/sagernet/sing/common"
 )
 
 type geoip2Country struct {
@@ -18,17 +19,36 @@ type Reader struct {
 	databaseType
 }
 
-func (r Reader) LookupCode(ipAddress net.IP) string {
+func (r Reader) LookupCode(ipAddress net.IP) []string {
 	switch r.databaseType {
 	case typeMaxmind:
 		var country geoip2Country
 		_ = r.Lookup(ipAddress, &country)
-		return country.Country.IsoCode
+		if country.Country.IsoCode == "" {
+			return []string{}
+		}
+		return []string{country.Country.IsoCode}
 
 	case typeSing:
 		var code string
 		_ = r.Lookup(ipAddress, &code)
-		return code
+		if code == "" {
+			return []string{}
+		}
+		return []string{code}
+
+	case typeMetaV0:
+		var record any
+		_ = r.Lookup(ipAddress, &record)
+		switch record := record.(type) {
+		case string:
+			return []string{record}
+		case []any: // lookup returned type of slice is []any
+			return common.Map(record, func(it any) string {
+				return it.(string)
+			})
+		}
+		return []string{}
 
 	default:
 		panic(fmt.Sprint("unknown geoip database type:", r.databaseType))
diff --git a/constant/path.go b/constant/path.go
index 09f1d89b..e23ae886 100644
--- a/constant/path.go
+++ b/constant/path.go
@@ -92,7 +92,8 @@ func (p *path) MMDB() string {
 			continue
 		} else {
 			if strings.EqualFold(fi.Name(), "Country.mmdb") ||
-				strings.EqualFold(fi.Name(), "geoip.db") {
+				strings.EqualFold(fi.Name(), "geoip.db") ||
+				strings.EqualFold(fi.Name(), "geoip.metadb") {
 				GeoipName = fi.Name()
 				return P.Join(p.homeDir, fi.Name())
 			}
diff --git a/dns/filters.go b/dns/filters.go
index 811fc976..47e7adcd 100644
--- a/dns/filters.go
+++ b/dns/filters.go
@@ -24,8 +24,13 @@ var geoIPMatcher *router.GeoIPMatcher
 
 func (gf *geoipFilter) Match(ip netip.Addr) bool {
 	if !C.GeodataMode {
-		code := mmdb.Instance().LookupCode(ip.AsSlice())
-		return !strings.EqualFold(code, gf.code) && !ip.IsPrivate()
+		codes := mmdb.Instance().LookupCode(ip.AsSlice())
+		for _, code := range codes {
+			if !strings.EqualFold(code, gf.code) && !ip.IsPrivate() {
+				return true
+			}
+		}
+		return false
 	}
 
 	if geoIPMatcher == nil {
diff --git a/rules/common/geoip.go b/rules/common/geoip.go
index 07b342ac..2f96c2ef 100644
--- a/rules/common/geoip.go
+++ b/rules/common/geoip.go
@@ -40,8 +40,13 @@ func (g *GEOIP) Match(metadata *C.Metadata) (bool, string) {
 			resolver.IsFakeBroadcastIP(ip), g.adapter
 	}
 	if !C.GeodataMode {
-		code := mmdb.Instance().LookupCode(ip.AsSlice())
-		return strings.EqualFold(code, g.country), g.adapter
+		codes := mmdb.Instance().LookupCode(ip.AsSlice())
+		for _, code := range codes {
+			if strings.EqualFold(code, g.country) {
+				return true, g.adapter
+			}
+		}
+		return false, g.adapter
 	}
 	return g.geoIPMatcher.Match(ip.AsSlice()), g.adapter
 }