Merge pull request #248 from squat/fix_forward_allow_rules

pkg/mesh/routes.go: add iptbales forward allow rules for segment.
squat · Nov 1, 2021 · 05e8ded · 05e8ded
2 parents 8a2c822 + ac65330
commit 05e8ded
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Showing 2 changed files with 30 additions and 3 deletions.
diff --git a/pkg/mesh/routes.go b/pkg/mesh/routes.go
@@ -249,9 +249,33 @@ func (t *Topology) Rules(cni, iptablesForwardRule bool) []iptables.Rule {
 	rules = append(rules, iptables.NewIPv6Chain("nat", "KILO-NAT"))
 	if cni {
 		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "nat", "POSTROUTING", "-s", t.subnet.String(), "-m", "comment", "--comment", "Kilo: jump to KILO-NAT chain", "-j", "KILO-NAT"))
-		if iptablesForwardRule {
-			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets from the pod subnet", "-s", t.subnet.String(), "-j", "ACCEPT"))
-			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets to the pod subnet", "-d", t.subnet.String(), "-j", "ACCEPT"))
+		// Some linux distros or docker will set forward DROP in the filter table.
+		// To still be able to have pod to pod communication we need to ALLOW packets from and to pod CIDRs within a location.
+		// Leader nodes will forward packets from all nodes within a location because they act as a gateway for them.
+		// Non leader nodes only need to allow packages from and to their own pod CIDR.
+		if iptablesForwardRule && t.leader {
+			for _, s := range t.segments {
+				if s.location == t.location {
+					// Make sure packets to and from pod cidrs are not dropped in the forward chain.
+					for _, c := range s.cidrs {
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets from the pod subnet", "-s", c.String(), "-j", "ACCEPT"))
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets to the pod subnet", "-d", c.String(), "-j", "ACCEPT"))
+					}
+					// Make sure packets to and from allowed location IPs are not dropped in the forward chain.
+					for _, c := range s.allowedLocationIPs {
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets from allowed location IPs", "-s", c.String(), "-j", "ACCEPT"))
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets to allowed location IPs", "-d", c.String(), "-j", "ACCEPT"))
+					}
+					// Make sure packets to and from private IPs are not dropped in the forward chain.
+					for _, c := range s.privateIPs {
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets from private IPs", "-s", oneAddressCIDR(c).String(), "-j", "ACCEPT"))
+						rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(c)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets to private IPs", "-d", oneAddressCIDR(c).String(), "-j", "ACCEPT"))
+					}
+				}
+			}
+		} else if iptablesForwardRule {
+			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets from the node's pod subnet", "-s", t.subnet.String(), "-j", "ACCEPT"))
+			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "filter", "FORWARD", "-m", "comment", "--comment", "Kilo: forward packets to the node's pod subnet", "-d", t.subnet.String(), "-j", "ACCEPT"))
 		}
 	}
 	for _, s := range t.segments {

diff --git a/pkg/mesh/topology.go b/pkg/mesh/topology.go
@@ -172,6 +172,8 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 			privateIPs:          privateIPs,
 			allowedLocationIPs:  allowedLocationIPs,
 		})
+		level.Debug(t.logger).Log("msg", "generated segment", "location", location, "allowedIPs", allowedIPs, "endpoint", topoMap[location][leader].Endpoint, "cidrs", cidrs, "hostnames", hostnames, "leader", leader, "privateIPs", privateIPs, "allowedLocationIPs", allowedLocationIPs)
+
 	}
 	// Sort the Topology segments so the result is stable.
 	sort.Slice(t.segments, func(i, j int) bool {
@@ -218,6 +220,7 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 		segment.allowedLocationIPs = t.filterAllowedLocationIPs(segment.allowedLocationIPs, segment.location)
 	}
 
+	level.Debug(t.logger).Log("msg", "generated topology", "location", t.location, "hostname", t.hostname, "wireGuardIP", t.wireGuardCIDR, "privateIP", t.privateIP, "subnet", t.subnet, "leader", t.leader)
 	return &t, nil
 }