From 3fb20b2edc218a225e9e31fd551c9761701fb5a8 Mon Sep 17 00:00:00 2001
From: Ed Warnicke <hagbard@gmail.com>
Date: Tue, 4 May 2021 19:46:57 -0500
Subject: [PATCH] Multiip fixes.

Signed-off-by: Ed Warnicke <hagbard@gmail.com>
---
 pkg/api/networkservice/ipcontext_helpers.go | 64 ++++++++++-----------
 1 file changed, 29 insertions(+), 35 deletions(-)

diff --git a/pkg/api/networkservice/ipcontext_helpers.go b/pkg/api/networkservice/ipcontext_helpers.go
index a237395..8db408b 100644
--- a/pkg/api/networkservice/ipcontext_helpers.go
+++ b/pkg/api/networkservice/ipcontext_helpers.go
@@ -33,25 +33,13 @@ func (i *IPContext) GetDstIPNets() []*net.IPNet {
 }
 
 // GetDstRoutesWithExplicitNextHop - returns routes with the Route.NextHop explicitly set to the first IP address
-// of the same address family (IPv4 or IPv6) from SrcIPAddrs if and only if Route.NextHop was initially nil
+// of the same address family (IPv4 or IPv6) from SrcIPAddrs if and only if Route.NextHop was initially nil and
+// the Route.NextHop is not in DstIPAddrs
 func (i *IPContext) GetDstRoutesWithExplicitNextHop() (routes []*Route) {
 	srcIPs := i.GetSrcIPNets()
-	ipv6NextHop := getNextHop(filterIPNetByFamily(IpFamily_IPV6, srcIPs))
-	ipv4NextHop := getNextHop(filterIPNetByFamily(IpFamily_IPV4, srcIPs))
-	for _, route := range i.GetDstRoutes() {
-		if route.GetPrefixIPNet() != nil && route.GetNextHopIP() == nil {
-			if ipv4NextHop != nil && route.GetPrefixIPNet().IP.To4() != nil {
-				route = route.Clone()
-				route.NextHop = ipv4NextHop.String()
-			}
-			if ipv6NextHop != nil && route.GetPrefixIPNet().IP.To4() == nil {
-				route = route.Clone()
-				route.NextHop = ipv6NextHop.String()
-			}
-		}
-		routes = append(routes, route)
-	}
-	return routes
+	ipv6Nets := filterIPNetByFamily(IpFamily_IPV6, srcIPs)
+	ipv4Nets := filterIPNetByFamily(IpFamily_IPV4, srcIPs)
+	return getRoutesWithExplicitNextHop(i.GetDstRoutes(), ipv4Nets, ipv6Nets)
 }
 
 // GetSrcRoutesWithExplicitNextHop - returns routes with the Route.NextHop explicitly set to the first IP address
@@ -59,22 +47,9 @@ func (i *IPContext) GetDstRoutesWithExplicitNextHop() (routes []*Route) {
 func (i *IPContext) GetSrcRoutesWithExplicitNextHop() (routes []*Route) {
 	// Set nextHop for any Route that is missing them
 	dstIPs := i.GetDstIPNets()
-	ipv6NextHop := getNextHop(filterIPNetByFamily(IpFamily_IPV6, dstIPs))
-	ipv4NextHop := getNextHop(filterIPNetByFamily(IpFamily_IPV4, dstIPs))
-	for _, route := range i.GetSrcRoutes() {
-		if route.GetPrefixIPNet() != nil && route.GetNextHopIP() == nil {
-			if ipv4NextHop != nil && route.GetPrefixIPNet().IP.To4() != nil {
-				route = route.Clone()
-				route.NextHop = ipv4NextHop.String()
-			}
-			if ipv6NextHop != nil && route.GetPrefixIPNet().IP.To4() == nil {
-				route = route.Clone()
-				route.NextHop = ipv6NextHop.String()
-			}
-		}
-		routes = append(routes, route)
-	}
-	return routes
+	ipv6Nets := filterIPNetByFamily(IpFamily_IPV6, dstIPs)
+	ipv4Nets := filterIPNetByFamily(IpFamily_IPV4, dstIPs)
+	return getRoutesWithExplicitNextHop(i.GetSrcRoutes(), ipv4Nets, ipv6Nets)
 }
 
 // GetSrcIPRoutes - returns routes for any SrcIPs that are not contained in the prefixes of at least one DstIP
@@ -109,6 +84,25 @@ func (i *IPContext) GetDstIPRoutes() (routes []*Route) {
 	return routes
 }
 
+func getRoutesWithExplicitNextHop(inRoutes []*Route, toIPv4Nets, toIPv6Nets []*net.IPNet) (routes []*Route) {
+	ipv6NextHop := getNextHop(toIPv6Nets)
+	ipv4NextHop := getNextHop(toIPv4Nets)
+	for _, route := range inRoutes {
+		if route.GetPrefixIPNet() != nil && route.GetNextHopIP() == nil {
+			if ipv4NextHop != nil && route.GetPrefixIPNet().IP.To4() != nil && !contains(toIPv4Nets, route.GetPrefixIPNet().IP) {
+				route = route.Clone()
+				route.NextHop = ipv4NextHop.String()
+			}
+			if ipv6NextHop != nil && route.GetPrefixIPNet().IP.To4() == nil && !contains(toIPv6Nets, route.GetPrefixIPNet().IP) {
+				route = route.Clone()
+				route.NextHop = ipv6NextHop.String()
+			}
+		}
+		routes = append(routes, route)
+	}
+	return routes
+}
+
 func getNextHop(ipNets []*net.IPNet) net.IP {
 	if len(ipNets) > 0 && ipNets[0] != nil {
 		return ipNets[0].IP
@@ -119,10 +113,10 @@ func getNextHop(ipNets []*net.IPNet) net.IP {
 func filterIPNetByFamily(family IpFamily_Family, ipNets []*net.IPNet) []*net.IPNet {
 	var rv []*net.IPNet
 	for _, ipNet := range ipNets {
-		if ipNet != nil && family == IpFamily_IPV4 && ipNet.IP.To4() == nil {
+		if ipNet != nil && family == IpFamily_IPV4 && ipNet.IP.To4() != nil {
 			rv = append(rv, ipNet)
 		}
-		if ipNet != nil && family == IpFamily_IPV6 && ipNet.IP.To4() != nil {
+		if ipNet != nil && family == IpFamily_IPV6 && ipNet.IP.To4() == nil {
 			rv = append(rv, ipNet)
 		}
 	}