fix: Improve automatic IP detection

go.mod

@@ -4,7 +4,7 @@ go 1.21.1
 
 require (
 	github.com/cloudflare/circl v1.3.6
-	github.com/heyvito/gateway v0.1.2
+	github.com/heyvito/defip v0.1.1
 	github.com/influxdata/tdigest v0.0.1
 	github.com/stretchr/testify v1.8.4
 	go.uber.org/zap v1.26.0

go.sum

@@ -4,8 +4,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.2.0 h1:+dTQ8DZQJz0Mb/HjFlkptS1FeQ4cWSnN941F8aEG4SQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
-github.com/heyvito/gateway v0.1.2 h1:4enCoosRHawlJlrUG7f5O0/f7yYz0TYQQJOBA1SlWFU=
-github.com/heyvito/gateway v0.1.2/go.mod h1:g7FIBBk+dKr9dsm+VXJM/4PUon0RdVc99sjePjKuFFw=
+github.com/heyvito/defip v0.1.1 h1:yQrlTPZp2K0b7MfWUHs5WHPBlct85jb1n8226jMA7w8=
+github.com/heyvito/defip v0.1.1/go.mod h1:rWEvk113oZKvLu/vYfxtQnvEF3PRYhzt2xOt4lzVM/s=
 github.com/influxdata/tdigest v0.0.1 h1:XpFptwYmnEKUqmkcDjrzffswZ3nvNeevbUSLPP/ZzIY=
 github.com/influxdata/tdigest v0.0.1/go.mod h1:Z0kXnxzbTC2qrx4NaIzYkE1k66+6oEDQTvL95hQFh5Y=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

internal/iputil/ip_list.go

@@ -2,7 +2,6 @@ package iputil
 
 import (
 	"fmt"
-	"github.com/heyvito/gateway"
 	"net"
 	"net/netip"
 	"slices"
@@ -39,33 +38,6 @@ func LocalAddresses() (IPList, error) {
 	return addrIPs, nil
 }
 
-func GetDefaultIP(preferIPv6 bool) (addr netip.Addr, err error) {
-	var ips []netip.Addr
-	ips, err = gateway.FindDefaultIPs()
-	if err != nil {
-		return
-	}
-
-	if preferIPv6 {
-		for _, v := range ips {
-			if v.Is6() {
-				return v, nil
-			}
-		}
-	} else {
-		for _, v := range ips {
-			return v, nil
-		}
-	}
-
-	for _, v := range ips {
-		return v, nil
-	}
-
-	err = NoAddressErr
-	return
-}
-
 func ConvertNetIP(in net.IP) netip.Addr {
 	if ip4 := in.To4(); ip4 != nil {
 		return netip.AddrFrom4([4]byte(ip4[:4]))

options.go

@@ -2,7 +2,7 @@ package eswim
 
 import (
 	"fmt"
-	"github.com/heyvito/gateway"
+	"github.com/heyvito/defip"
 	"go.uber.org/zap"
 	"math"
 	"net/netip"
@@ -123,6 +123,12 @@ type Options struct {
 }
 
 func (o *Options) normalize() error {
+	if o.LogHandler == nil {
+		o.LogHandler = zap.NewNop()
+	}
+
+	logger := o.LogHandler.With(zap.String("facility", "options"))
+
 	if !o.InsecureDisableCrypto && len(o.CryptoKey) != 16 {
 		return fmt.Errorf("CryptoKey must have 16 bytes")
 	}
@@ -157,52 +163,27 @@ func (o *Options) normalize() error {
 		}
 	}
 
-	if o.LogHandler == nil {
-		o.LogHandler = zap.NewNop()
-	}
-
 	if o.HostAddresses.IPv4Address == nil || o.HostAddresses.IPv6Address == nil {
-		allIPs, err := gateway.FindDefaultIPs()
-		if err != nil {
-			return fmt.Errorf("failed detecting IP addresses: %w", err)
-		}
-
 		if o.HostAddresses.IPv4Address == nil {
-			o.HostAddresses.IPv4Address = filterIP(allIPs, netip.Addr.Is4)
+			if ip, err := defip.FindDefaultIP(defip.NetRouteKindV4); err == nil {
+				o.HostAddresses.IPv4Address = ip
+				logger.Debug("Automatically selected IPv4", zap.String("addr", ip.String()))
+			} else {
+				logger.Warn("IPv4 has not been explicitly disabled, but no usable IPv4 could be found. Disabling...")
+				o.HostAddresses.IPv4Address = IgnoreFamilyAddr
+			}
 		}
 
 		if o.HostAddresses.IPv6Address == nil {
-			o.HostAddresses.IPv6Address = filterIP(allIPs, netip.Addr.Is6)
+			if ip, err := defip.FindDefaultIP(defip.NetRouteKindV6); err == nil {
+				o.HostAddresses.IPv6Address = ip
+				logger.Debug("Automatically selected IPv6", zap.String("addr", ip.String()))
+			} else {
+				logger.Warn("IPv6 has not been explicitly disabled, but no usable IPv6 could be found. Disabling...")
+				o.HostAddresses.IPv6Address = IgnoreFamilyAddr
+			}
 		}
 	}
 
 	return nil
 }
-
-func filterIP(list []netip.Addr, filter func(netip.Addr) bool) *netip.Addr {
-	var anyLocal, anyNonLocal netip.Addr
-
-	for _, ip := range list {
-		isLinkLocal := ip.IsLinkLocalUnicast() || ip.IsLinkLocalUnicast()
-		if !filter(ip) {
-			continue
-		}
-
-		if isLinkLocal && !anyLocal.IsValid() {
-			anyLocal = ip
-		} else if !anyNonLocal.IsValid() {
-			anyNonLocal = ip
-		}
-
-		if anyLocal.IsValid() && anyNonLocal.IsValid() {
-			break
-		}
-	}
-
-	if anyLocal.IsValid() {
-		return &anyLocal
-	} else if anyNonLocal.IsValid() {
-		return &anyNonLocal
-	}
-	return nil
-}