Fasten quitting l2tp game

Drop routes as quickly as possible to lose as few packets as possible in the
meanwhile.

cluster.c

@@ -435,8 +435,7 @@ static void send_heartbeat(int seq, uint8_t *data, int size)
 	if (size > sizeof(past_hearts[0].data))
 	{
 		LOG(0, 0, 0, "Tried to heartbeat something larger than the maximum packet!\n");
-		kill(0, SIGTERM);
-		exit(1);
+		crash();
 	}
 	i = seq % HB_HISTORY_SIZE;
 	past_hearts[i].seq = seq;
@@ -903,8 +902,7 @@ static int hb_add_type(uint8_t **p, int type, int id)
 			break;
 		default:
 			LOG(0, 0, 0, "Found an invalid type in heart queue! (%d)\n", type);
-			kill(0, SIGTERM);
-			exit(1);
+			crash();
 	}
 	return 0;
 }
@@ -951,8 +949,7 @@ void cluster_heartbeat()
 
 	if (p > (buff + sizeof(buff))) {	// Did we somehow manage to overun the buffer?
 		LOG(0, 0, 0, "FATAL: Overran the heartbeat buffer! This is fatal. Exiting. (size %d)\n", (int) (p - buff));
-		kill(0, SIGTERM);
-		exit(1);
+		crash();
 	}
 
 		//
@@ -1011,8 +1008,7 @@ void cluster_heartbeat()
 		// Did we do something wrong?
 	if (p > (buff + sizeof(buff))) {	// Did we somehow manage to overun the buffer?
 		LOG(0, 0, 0, "Overran the heartbeat buffer now! This is fatal. Exiting. (size %d)\n", (int) (p - buff));
-		kill(0, SIGTERM);
-		exit(1);
+		crash();
 	}
 
 	LOG(4, 0, 0, "Sending v%d heartbeat #%d, change #%" PRIu64 " with %d changes "
@@ -1960,8 +1956,7 @@ static int cluster_process_heartbeat(uint8_t *data, int size, int more, uint8_t
 			LOG(0, 0, 0, "They've seen more state changes (%" PRIu64 " vs my %" PRIu64 ") so I'm gone!\n",
 					h->table_version, config->cluster_table_version);
 
-			kill(0, SIGTERM);
-			exit(1);
+			crash();
 		}
 
 		if (h->table_version < config->cluster_table_version)
@@ -1969,8 +1964,7 @@ static int cluster_process_heartbeat(uint8_t *data, int size, int more, uint8_t
 
 		if (basetime > h->basetime) {
 			LOG(0, 0, 0, "They're an older master than me so I'm gone!\n");
-			kill(0, SIGTERM);
-			exit(1);
+			crash();
 		}
 
 		if (basetime < h->basetime)
@@ -1978,8 +1972,7 @@ static int cluster_process_heartbeat(uint8_t *data, int size, int more, uint8_t
 
 		if (my_address < addr) { // Tie breaker.
 			LOG(0, 0, 0, "They're a higher IP address than me, so I'm gone!\n");
-			kill(0, SIGTERM);
-			exit(1);
+			crash();
 		}
 
 			//
@@ -2366,8 +2359,7 @@ int processcluster(uint8_t *data, int size, in_addr_t addr)
 		}
 
 		LOG(0, 0, 0, "Received a valid C_KILL: I'm going to die now.\n");
-		kill(0, SIGTERM);
-		exit(0);	// Lets be paranoid;
+		crash();
 		return -1;		// Just signalling the compiler.
 
 	case C_HEARTBEAT:

l2tpns.c

@@ -2119,6 +2119,66 @@ static int setupif(int ifidx, uint32_t mru, int config_addr)
 	return 0;
 }
 
+//
+// Quickly drop the gateway from the interface
+static int disableif(int ifidx)
+{
+	struct {
+		// interface setting
+		struct nlmsghdr nh;
+		union {
+			struct ifinfomsg ifinfo;
+			struct ifaddrmsg ifaddr;
+		} ifmsg;
+		char rtdata[32]; // 32 should be enough
+	} req;
+	in_addr_t ip;
+
+	memset(&req, 0, sizeof(req));
+
+	req.nh.nlmsg_type = RTM_DELADDR;
+	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_MULTI;
+	req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr));
+
+	req.ifmsg.ifaddr.ifa_family = AF_INET;
+	req.ifmsg.ifaddr.ifa_prefixlen = 32;
+	req.ifmsg.ifaddr.ifa_scope = RT_SCOPE_UNIVERSE;
+	req.ifmsg.ifaddr.ifa_index = ifidx;
+
+	if (config->nbmultiaddress > 1)
+	{
+		int i;
+		for (i = 0; i < config->nbmultiaddress ; i++)
+		{
+			ip = config->iftun_n_address[i];
+			rtnetlink_addattr(&req.nh, IFA_LOCAL, &ip, sizeof(ip));
+			if (rtnetlink_send(&req.nh) < 0)
+				return -1;
+		}
+	}
+	else
+	{
+		if (config->iftun_address)
+			ip = config->iftun_address;
+		else
+			ip = 0x01010101; // 1.1.1.1
+		rtnetlink_addattr(&req.nh, IFA_LOCAL, &ip, sizeof(ip));
+
+		if (rtnetlink_send(&req.nh) < 0)
+			return -1;
+	}
+
+	memset(&req, 0, sizeof(req));
+
+	req.nh.nlmsg_type = NLMSG_DONE;
+	req.nh.nlmsg_len = NLMSG_LENGTH(0);
+
+	if (rtnetlink_send(&req.nh) < 0)
+		return -1;
+
+	return 0;
+}
+
 // set up LAC UDP ports
 static int initlacudp(int *pudpfd, in_addr_t ip_dest, uint16_t port_dest)
 {
@@ -3821,6 +3881,33 @@ static void tunnelshutdown(tunnelidt t, char *reason, int result, int error, cha
 	}
 }
 
+static void drop_routes(void)
+{
+	unsigned i;
+
+	LOG(1, 0, 0, "Disabling receiving l2tp\n");
+	// Disable receiving l2tp trafic first since we don't forward to master any more
+	disableif(tunidx);
+	LOG(1, 0, 0, "Dropping routes\n");
+	// Disable receiving Internet trafic
+	for (i = 1; i <= config->cluster_highest_sessionid ; ++i)
+	{
+		routesset(i, &session[i], 0);
+		routes6set(i, &session[i], 0);
+	}
+}
+
+//
+// We ended up in an odd state, better stop here as quickly as possible before
+// causing trouble to the rest of the cluster
+//
+void crash(void)
+{
+	kill(0, SIGTERM);
+	drop_routes();
+	exit(1);
+}
+
 // read and process packet on tunnel (UDP)
 void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexudpfd)
 {
@@ -6017,6 +6104,7 @@ static void mainloop(void)
 			}
 		}
 	}
+	LOG(1, 0, 0, "Leaving...\n");
 
 		// Are we the master and shutting down??
 	if (config->cluster_iam_master)
@@ -6032,6 +6120,14 @@ static void mainloop(void)
 
 	//
 	// Important!!! We MUST not process any packets past this point!
+	//
+
+	//
+	// Now drop routes as quickly as possible to lose as few packets as
+	// possible in the meanwhile
+	//
+	drop_routes();
+
 	LOG(1, 0, 0, "Shutdown complete\n");
 }
 

l2tpns.h

@@ -1037,6 +1037,7 @@ void throttle_session(sessionidt s, int rate_in, int rate_out);
 int load_tunnel(tunnelidt, tunnelt *);
 int load_session(sessionidt, sessiont *);
 void become_master(void);	// We're the master; kick off any required master initializations.
+void crash(void);		// We messed up. Die.
 
 
 // cli.c