core: Change net.IP to netip.Addr; use netip.Prefix (#4966)

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

5 files changed, 50 insertions, 57 deletions

diff --git a/caddyconfig/httpcaddyfile/addresses.go b/caddyconfig/httpcaddyfile/addresses.go
index 0553c08..e7a7cdb 100644
--- a/caddyconfig/httpcaddyfile/addresses.go
+++ b/caddyconfig/httpcaddyfile/addresses.go
@@ -17,6 +17,7 @@ package httpcaddyfile
 import (
 	"fmt"
 	"net"
+	"net/netip"
 	"reflect"
 	"sort"
 	"strconv"
@@ -354,9 +355,9 @@ func (a Address) Normalize() Address {
 
 	// ensure host is normalized if it's an IP address
 	host := strings.TrimSpace(a.Host)
-	if ip := net.ParseIP(host); ip != nil {
-		if ipv6 := ip.To16(); ipv6 != nil && ipv6.DefaultMask() == nil {
-			host = ipv6.String()
+	if ip, err := netip.ParseAddr(host); err == nil {
+		if ip.Is6() && !ip.Is4() && !ip.Is4In6() {
+			host = ip.String()
 		}
 	}
 
diff --git a/listeners.go b/listeners.go
index c7d6d52..8698387 100644
--- a/listeners.go
+++ b/listeners.go
@@ -20,6 +20,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"net/netip"
 	"os"
 	"strconv"
 	"strings"
@@ -400,7 +401,7 @@ func (na NetworkAddress) isLoopback() bool {
 	if na.Host == "localhost" {
 		return true
 	}
-	if ip := net.ParseIP(na.Host); ip != nil {
+	if ip, err := netip.ParseAddr(na.Host); err == nil {
 		return ip.IsLoopback()
 	}
 	return false
@@ -410,7 +411,7 @@ func (na NetworkAddress) isWildcardInterface() bool {
 	if na.Host == "" {
 		return true
 	}
-	if ip := net.ParseIP(na.Host); ip != nil {
+	if ip, err := netip.ParseAddr(na.Host); err == nil {
 		return ip.IsUnspecified()
 	}
 	return false
diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index d6bbe7e..5056c9a 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"net/netip"
 	"net/textproto"
 	"net/url"
 	"path"
@@ -171,7 +172,7 @@ type (
 
 		// cidrs and zones vars should aligned always in the same
 		// length and indexes for matching later
-		cidrs  []*net.IPNet
+		cidrs  []*netip.Prefix
 		zones  []string
 		logger *zap.Logger
 	}
@@ -1311,27 +1312,24 @@ func (m *MatchRemoteIP) Provision(ctx caddy.Context) error {
 			m.zones = append(m.zones, "")
 		}
 		if strings.Contains(str, "/") {
-			_, ipNet, err := net.ParseCIDR(str)
+			ipNet, err := netip.ParsePrefix(str)
 			if err != nil {
 				return fmt.Errorf("parsing CIDR expression '%s': %v", str, err)
 			}
-			m.cidrs = append(m.cidrs, ipNet)
+			m.cidrs = append(m.cidrs, &ipNet)
 		} else {
-			ip := net.ParseIP(str)
-			if ip == nil {
-				return fmt.Errorf("invalid IP address: %s", str)
+			ipAddr, err := netip.ParseAddr(str)
+			if err != nil {
+				return fmt.Errorf("invalid IP address: '%s': %v", str, err)
 			}
-			mask := len(ip) * 8
-			m.cidrs = append(m.cidrs, &net.IPNet{
-				IP:   ip,
-				Mask: net.CIDRMask(mask, mask),
-			})
+			ipNew := netip.PrefixFrom(ipAddr, ipAddr.BitLen())
+			m.cidrs = append(m.cidrs, &ipNew)
 		}
 	}
 	return nil
 }
 
-func (m MatchRemoteIP) getClientIP(r *http.Request) (net.IP, string, error) {
+func (m MatchRemoteIP) getClientIP(r *http.Request) (netip.Addr, string, error) {
 	remote := r.RemoteAddr
 	zoneID := ""
 	if m.Forwarded {
@@ -1350,11 +1348,11 @@ func (m MatchRemoteIP) getClientIP(r *http.Request) (net.IP, string, error) {
 		ipStr = split[0]
 		zoneID = split[1]
 	}
-	ip := net.ParseIP(ipStr)
-	if ip == nil {
-		return nil, zoneID, fmt.Errorf("invalid client IP address: %s", ipStr)
+	ipAddr, err := netip.ParseAddr(ipStr)
+	if err != nil {
+		return netip.IPv4Unspecified(), "", err
 	}
-	return ip, zoneID, nil
+	return ipAddr, zoneID, nil
 }
 
 // Match returns true if r matches m.
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index cc6b530..0890306 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -24,6 +24,7 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptrace"
+	"net/netip"
 	"net/textproto"
 	"net/url"
 	"regexp"
@@ -180,7 +181,7 @@ type Handler struct {
 	DynamicUpstreams UpstreamSource    `json:"-"`
 
 	// Holds the parsed CIDR ranges from TrustedProxies
-	trustedProxies []*net.IPNet
+	trustedProxies []netip.Prefix
 
 	// Holds the named response matchers from the Caddyfile while adapting
 	responseMatchers map[string]caddyhttp.ResponseMatcher
@@ -251,24 +252,18 @@ func (h *Handler) Provision(ctx caddy.Context) error {
 	// parse trusted proxy CIDRs ahead of time
 	for _, str := range h.TrustedProxies {
 		if strings.Contains(str, "/") {
-			_, ipNet, err := net.ParseCIDR(str)
+			ipNet, err := netip.ParsePrefix(str)
 			if err != nil {
-				return fmt.Errorf("parsing CIDR expression: %v", err)
+				return fmt.Errorf("parsing CIDR expression: '%s': %v", str, err)
 			}
 			h.trustedProxies = append(h.trustedProxies, ipNet)
 		} else {
-			ip := net.ParseIP(str)
-			if ip == nil {
-				return fmt.Errorf("invalid IP address: %s", str)
-			}
-			if ipv4 := ip.To4(); ipv4 != nil {
-				ip = ipv4
+			ipAddr, err := netip.ParseAddr(str)
+			if err != nil {
+				return fmt.Errorf("invalid IP address: '%s': %v", str, err)
 			}
-			mask := len(ip) * 8
-			h.trustedProxies = append(h.trustedProxies, &net.IPNet{
-				IP:   ip,
-				Mask: net.CIDRMask(mask, mask),
-			})
+			ipNew := netip.PrefixFrom(ipAddr, ipAddr.BitLen())
+			h.trustedProxies = append(h.trustedProxies, ipNew)
 		}
 	}
 
@@ -672,15 +667,15 @@ func (h Handler) addForwardedHeaders(req *http.Request) error {
 	if before, _, found := strings.Cut(clientIP, "%"); found {
 		clientIP = before
 	}
-	ip := net.ParseIP(clientIP)
-	if ip == nil {
-		return fmt.Errorf("invalid client IP address: %s", clientIP)
+	ipAddr, err := netip.ParseAddr(clientIP)
+	if err != nil {
+		return fmt.Errorf("invalid IP address: '%s': %v", clientIP, err)
 	}
 
 	// Check if the client is a trusted proxy
 	trusted := false
 	for _, ipRange := range h.trustedProxies {
-		if ipRange.Contains(ip) {
+		if ipRange.Contains(ipAddr) {
 			trusted = true
 			break
 		}
diff --git a/modules/caddytls/matchers.go b/modules/caddytls/matchers.go
index d41492f..4a22bc0 100644
--- a/modules/caddytls/matchers.go
+++ b/modules/caddytls/matchers.go
@@ -18,6 +18,7 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net"
+	"net/netip"
 	"strings"
 
 	"github.com/caddyserver/caddy/v2"
@@ -65,8 +66,8 @@ type MatchRemoteIP struct {
 	// The IPs or CIDR ranges to *NOT* match.
 	NotRanges []string `json:"not_ranges,omitempty"`
 
-	cidrs    []*net.IPNet
-	notCidrs []*net.IPNet
+	cidrs    []netip.Prefix
+	notCidrs []netip.Prefix
 	logger   *zap.Logger
 }
 
@@ -105,38 +106,35 @@ func (m MatchRemoteIP) Match(hello *tls.ClientHelloInfo) bool {
 	if err != nil {
 		ipStr = remoteAddr // weird; maybe no port?
 	}
-	ip := net.ParseIP(ipStr)
-	if ip == nil {
+	ipAddr, err := netip.ParseAddr(ipStr)
+	if err != nil {
 		m.logger.Error("invalid client IP addresss", zap.String("ip", ipStr))
 		return false
 	}
-	return (len(m.cidrs) == 0 || m.matches(ip, m.cidrs)) &&
-		(len(m.notCidrs) == 0 || !m.matches(ip, m.notCidrs))
+	return (len(m.cidrs) == 0 || m.matches(ipAddr, m.cidrs)) &&
+		(len(m.notCidrs) == 0 || !m.matches(ipAddr, m.notCidrs))
 }
 
-func (MatchRemoteIP) parseIPRange(str string) ([]*net.IPNet, error) {
-	var cidrs []*net.IPNet
+func (MatchRemoteIP) parseIPRange(str string) ([]netip.Prefix, error) {
+	var cidrs []netip.Prefix
 	if strings.Contains(str, "/") {
-		_, ipNet, err := net.ParseCIDR(str)
+		ipNet, err := netip.ParsePrefix(str)
 		if err != nil {
 			return nil, fmt.Errorf("parsing CIDR expression: %v", err)
 		}
 		cidrs = append(cidrs, ipNet)
 	} else {
-		ip := net.ParseIP(str)
-		if ip == nil {
-			return nil, fmt.Errorf("invalid IP address: %s", str)
+		ipAddr, err := netip.ParseAddr(str)
+		if err != nil {
+			return nil, fmt.Errorf("invalid IP address: '%s': %v", str, err)
 		}
-		mask := len(ip) * 8
-		cidrs = append(cidrs, &net.IPNet{
-			IP:   ip,
-			Mask: net.CIDRMask(mask, mask),
-		})
+		ip := netip.PrefixFrom(ipAddr, ipAddr.BitLen())
+		cidrs = append(cidrs, ip)
 	}
 	return cidrs, nil
 }
 
-func (MatchRemoteIP) matches(ip net.IP, ranges []*net.IPNet) bool {
+func (MatchRemoteIP) matches(ip netip.Addr, ranges []netip.Prefix) bool {
 	for _, ipRange := range ranges {
 		if ipRange.Contains(ip) {
 			return true