From ec3e3add9e75d29944dff6710e641aee06f7c89a Mon Sep 17 00:00:00 2001
From: Denys Smirnov <denys@livekit.io>
Date: Wed, 16 Oct 2024 13:54:48 +0300
Subject: [PATCH] Type safe IP checks for SIP Trunks.

---
 sip/sip.go      | 18 +++++++++---------
 sip/sip_test.go | 13 +++++++++++--
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/sip/sip.go b/sip/sip.go
index 8d9e3b16..a812c5bb 100644
--- a/sip/sip.go
+++ b/sip/sip.go
@@ -267,13 +267,13 @@ func ValidateTrunks(trunks []*livekit.SIPInboundTrunkInfo) error {
 	return nil
 }
 
-func matchAddrMask(addr string, mask string) bool {
+func matchAddrMask(ip netip.Addr, mask string) bool {
 	if !strings.Contains(mask, "/") {
-		return addr == mask
-	}
-	ip, err := netip.ParseAddr(addr)
-	if err != nil {
-		return false
+		expIP, err := netip.ParseAddr(mask)
+		if err != nil {
+			return false
+		}
+		return ip == expIP
 	}
 	pref, err := netip.ParsePrefix(mask)
 	if err != nil {
@@ -282,8 +282,8 @@ func matchAddrMask(addr string, mask string) bool {
 	return pref.Contains(ip)
 }
 
-func matchAddrMasks(addr string, masks []string) bool {
-	if addr == "" || len(masks) == 0 {
+func matchAddrMasks(addr netip.Addr, masks []string) bool {
+	if !addr.IsValid() || len(masks) == 0 {
 		return true
 	}
 	for _, mask := range masks {
@@ -309,7 +309,7 @@ func matchNumbers(num string, allowed []string) bool {
 
 // MatchTrunk finds a SIP Trunk definition matching the request.
 // Returns nil if no rules matched or an error if there are conflicting definitions.
-func MatchTrunk(trunks []*livekit.SIPInboundTrunkInfo, srcIP, calling, called string) (*livekit.SIPInboundTrunkInfo, error) {
+func MatchTrunk(trunks []*livekit.SIPInboundTrunkInfo, srcIP netip.Addr, calling, called string) (*livekit.SIPInboundTrunkInfo, error) {
 	var (
 		selectedTrunk   *livekit.SIPInboundTrunkInfo
 		defaultTrunk    *livekit.SIPInboundTrunkInfo
diff --git a/sip/sip_test.go b/sip/sip_test.go
index 4c233b42..fa14174e 100644
--- a/sip/sip_test.go
+++ b/sip/sip_test.go
@@ -16,6 +16,7 @@ package sip
 
 import (
 	"fmt"
+	"net/netip"
 	"strconv"
 	"testing"
 
@@ -219,7 +220,13 @@ func TestSIPMatchTrunk(t *testing.T) {
 				src = "1.1.1.1"
 			}
 			trunks := toInboundTrunks(c.trunks)
-			got, err := MatchTrunk(trunks, src, from, to)
+			var srcIP netip.Addr
+			if src != "" {
+				var err error
+				srcIP, err = netip.ParseAddr(src)
+				require.NoError(t, err)
+			}
+			got, err := MatchTrunk(trunks, srcIP, from, to)
 			if c.expErr {
 				require.Error(t, err)
 				require.Nil(t, got)
@@ -657,7 +664,9 @@ func TestMatchIP(t *testing.T) {
 	}
 	for _, c := range cases {
 		t.Run(c.mask, func(t *testing.T) {
-			got := matchAddrMask(c.addr, c.mask)
+			ip, err := netip.ParseAddr(c.addr)
+			require.NoError(t, err)
+			got := matchAddrMask(ip, c.mask)
 			require.Equal(t, c.exp, got)
 		})
 	}