[lxc-devel] [lxd/master] lxd/networks: Improve dnsmasq leases cleanup

[stgraber on Github]

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From 1d8a3b6ebf5d339ccfae238239102b9d3c79bbc2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgraber at ubuntu.com>
Date: Sun, 15 Jul 2018 01:15:24 -0400
Subject: [PATCH] lxd/networks: Improve dnsmasq leases cleanup
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

dnsmasq doesn't record the MAC address for IPv6 leases, so add logic to
detect that case and then cleanup base on the container name.

This isn't perfect as there's no guarantee that the reported name over
DHCP matches the container's LXD name, but there's really nothing else
to match against.

Closes #4635

Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
---
 lxd/container_lxc.go  |  4 ++--
 lxd/networks_utils.go | 19 ++++++++++++-------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lxd/container_lxc.go b/lxd/container_lxc.go
index 2cee8ad1de..d2636e43fd 100644
--- a/lxd/container_lxc.go
+++ b/lxd/container_lxc.go
@@ -3367,7 +3367,7 @@ func (c *containerLXC) Delete() error {
 	// Update network files
 	networkUpdateStatic(c.state, "")
 	for k, m := range c.expandedDevices {
-		if (m["type"] != "nic" && m["type"] != "infiniband") || m["nictype"] != "bridged" || (m["ipv4.address"] == "" && m["ipv6.address"] == "") {
+		if m["type"] != "nic" || m["nictype"] != "bridged" {
 			continue
 		}
 
@@ -3376,7 +3376,7 @@ func (c *containerLXC) Delete() error {
 			continue
 		}
 
-		networkClearLease(c.state, m["parent"], m["hwaddr"])
+		networkClearLease(c.state, c.name, m["parent"], m["hwaddr"])
 	}
 
 	logger.Info("Deleted container", ctxMap)
diff --git a/lxd/networks_utils.go b/lxd/networks_utils.go
index f407099d26..4169ff74e5 100644
--- a/lxd/networks_utils.go
+++ b/lxd/networks_utils.go
@@ -934,7 +934,7 @@ func networkGetMacSlice(hwaddr string) []string {
 	return buf
 }
 
-func networkClearLease(s *state.State, network string, hwaddr string) error {
+func networkClearLease(s *state.State, name string, network string, hwaddr string) error {
 	leaseFile := shared.VarPath("networks", network, "dnsmasq.leases")
 
 	// Check that we are in fact running a dnsmasq for the network
@@ -966,6 +966,7 @@ func networkClearLease(s *state.State, network string, hwaddr string) error {
 		return err
 	}
 
+	knownMac := networkGetMacSlice(hwaddr)
 	for _, lease := range strings.Split(string(leases), "\n") {
 		if lease == "" {
 			continue
@@ -973,12 +974,16 @@ func networkClearLease(s *state.State, network string, hwaddr string) error {
 
 		fields := strings.Fields(lease)
 		if len(fields) > 2 {
-			leaseMac := networkGetMacSlice(fields[1])
-			leaseMacStr := strings.Join(leaseMac, ":")
-			knownMac := networkGetMacSlice(hwaddr)
-			knownMacStr := strings.Join(
-				knownMac[len(knownMac)-len(leaseMac):], ":")
-			if knownMacStr == leaseMacStr {
+			if strings.Contains(fields[1], ":") {
+				leaseMac := networkGetMacSlice(fields[1])
+				leaseMacStr := strings.Join(leaseMac, ":")
+
+				knownMacStr := strings.Join(knownMac[len(knownMac)-len(leaseMac):], ":")
+				if knownMacStr == leaseMacStr {
+					continue
+				}
+			} else if len(fields) > 3 && fields[3] == name {
+				// Mostly IPv6 leases which don't contain a MAC address...
 				continue
 			}
 		}