kernel-pfroute: Delete interfaces on RTM_IFANNOUNCE/IFAN_DEPARTURE events

We actually never deleted cached interfaces.  So if the kernel reuses
interface indices events for newly created interfaces could have been
associated with interface objects of deactivated and deleted interfaces.

Since we also didn't update the interface name when such an interface
got reactivated we ended up using the old name e.g. to install routes.

A trigger for this was the deletion and recreation of TUN devices during
reauthentication of SAs that use virtual IPs.

1 files changed, 38 insertions, 0 deletions

diff --git a/src/libhydra/plugins/kernel_pfroute/kernel_pfroute_net.c b/src/libhydra/plugins/kernel_pfroute/kernel_pfroute_net.c
index 32157bbb4..8121969fd 100644
--- a/src/libhydra/plugins/kernel_pfroute/kernel_pfroute_net.c
+++ b/src/libhydra/plugins/kernel_pfroute/kernel_pfroute_net.c
@@ -876,6 +876,37 @@ static void process_link(private_kernel_pfroute_net_t *this,
 }
 
 /**
+ * Process an RTM_IFANNOUNCE message from the kernel
+ */
+static void process_announce(private_kernel_pfroute_net_t *this,
+							 struct if_announcemsghdr *msg)
+{
+	enumerator_t *enumerator;
+	iface_entry_t *iface;
+
+	if (msg->ifan_what != IFAN_DEPARTURE)
+	{
+		/* we handle new interfaces in process_link() */
+		return;
+	}
+
+	this->lock->write_lock(this->lock);
+	enumerator = this->ifaces->create_enumerator(this->ifaces);
+	while (enumerator->enumerate(enumerator, &iface))
+	{
+		if (iface->ifindex == msg->ifan_index)
+		{
+			DBG1(DBG_KNL, "interface %s disappeared", iface->ifname);
+			this->ifaces->remove_at(this->ifaces, enumerator);
+			iface_entry_destroy(iface);
+			break;
+		}
+	}
+	enumerator->destroy(enumerator);
+	this->lock->unlock(this->lock);
+}
+
+/**
  * Process an RTM_*ROUTE message from the kernel
  */
 static void process_route(private_kernel_pfroute_net_t *this,
@@ -895,6 +926,7 @@ static bool receive_events(private_kernel_pfroute_net_t *this, int fd,
 			struct rt_msghdr rtm;
 			struct if_msghdr ifm;
 			struct ifa_msghdr ifam;
+			struct if_announcemsghdr ifanm;
 		};
 		char buf[sizeof(struct sockaddr_storage) * RTAX_MAX];
 	} msg;
@@ -935,6 +967,9 @@ static bool receive_events(private_kernel_pfroute_net_t *this, int fd,
 		case RTM_IFINFO:
 			hdrlen = sizeof(msg.ifm);
 			break;
+		case RTM_IFANNOUNCE:
+			hdrlen = sizeof(msg.ifanm);
+			break;
 		case RTM_ADD:
 		case RTM_DELETE:
 		case RTM_GET:
@@ -957,6 +992,9 @@ static bool receive_events(private_kernel_pfroute_net_t *this, int fd,
 		case RTM_IFINFO:
 			process_link(this, &msg.ifm);
 			break;
+		case RTM_IFANNOUNCE:
+			process_announce(this, &msg.ifanm);
+			break;
 		case RTM_ADD:
 		case RTM_DELETE:
 			process_route(this, &msg.rtm);