network: add timeout for client connections

Somtimes client connetions will not close therfore add a timeout. Add a
new timer that checks every 5s if we did not receive anything from a
client for (default) 60s. Can be configured via client_timeout.

Code is based on the work of ptpt52.

Signed-off-by: Nick Hainke <vincent@systemli.org>

CONFIGURE.md

@@ -263,6 +263,7 @@ grep 'CONFIG-T:' `find . -type f -name "*.[ch]"`|sed 's/^.*CONFIG-.: *\(.*\)$/|\
 -->
 |Parameter|Purpose|Notes [Default is bracketed]|
 |---------|-------|-----|
+|client_timeout|Timespan until a client is seen as disconnected|[60]|
 |remove_ap|Timer to remove expired AP entries from core data set|[460]|
 |remove_client|Timer to remove expired client entries from core data set|[15]|
 |remove_probe|Timer to remove expired PROBE and BEACON entries from core data set|[30]|

dawn-config

@@ -17,6 +17,7 @@ config hostapd
 	option hostapd_dir '/var/run/hostapd'
 
 config times
+	option client_timeout '60'
 	option update_client '10'
 	option remove_client '15'
 	option remove_probe '30'

src/include/datastorage.h

@@ -109,6 +109,7 @@ struct time_config_s {
     time_t update_tcp_con; // Refresh network connections
     time_t update_chan_util; // Refresh per radio / SSID channel util info
     time_t update_beacon_reports; // Request BEACON from capable clients
+    time_t client_timeout; // Check for client timeouts.
 };
 
 struct local_config_s {

src/include/tcpsocket.h

@@ -5,6 +5,7 @@
 #include <netinet/in.h>
 
 #define ARRAY_NETWORK_LEN 50
+#define CHECK_CLIENT_TIMEOUT 5
 
 struct network_con_s {
     struct list_head list;
@@ -36,6 +37,11 @@ int run_server(int port);
  */
 void send_tcp(char *msg);
 
+/**
+ * Check sockets for client timeouts.
+ */
+void check_client_timeout(int timeout);
+
 /**
  * Debug message.
  */

src/network/tcpsocket.c

@@ -14,6 +14,7 @@
 #define HEADER_SIZE sizeof(uint32_t)
 
 LIST_HEAD(tcp_sock_list);
+LIST_HEAD(cli_list);
 
 struct network_con_s *tcp_list_contains_address(struct sockaddr_in entry);
 
@@ -27,6 +28,7 @@ enum socket_read_status {
 };
 
 struct client {
+    struct list_head list;
     struct sockaddr_in sin;
 
     struct ustream_fd s;
@@ -36,6 +38,7 @@ struct client {
     enum socket_read_status state; // messge read state
     uint32_t final_len; // full message length
     uint32_t curr_len; // bytes read so far
+    time_t time_alive;
 };
 
 
@@ -48,6 +51,7 @@ static void client_close(struct ustream *s) {
     ustream_free(s);
     dawn_unregmem(s);
     close(cl->s.fd.fd);
+    list_del(&cl->list);
     dawn_free(cl);
     cl = NULL;
 }
@@ -199,6 +203,7 @@ static void client_read_cb(struct ustream *s, int bytes) {
             cl->final_len = 0;
             dawn_free(cl->str);
             cl->str = NULL;
+            cl->time_alive = time(0);
         }
     }
 
@@ -228,6 +233,8 @@ static void server_cb(struct uloop_fd *fd, unsigned int events) {
     cl->s.stream.notify_read = client_read_cb;
     cl->s.stream.notify_state = client_notify_state;
     cl->s.stream.notify_write = client_notify_write;
+    cl->time_alive = time(0);
+    list_add(&cl->list, &cli_list);
     ustream_fd_init(&cl->s, sfd);
     dawn_regmem(&cl->s);
     next_client = NULL;  // TODO: Why is this here?  To avoid resetting if above return happens?
@@ -422,6 +429,18 @@ void send_tcp(char *msg) {
     }
 }
 
+void check_client_timeout(int timeout) {
+    struct client *cl, *tmp;
+    time_t now = time(0);
+    list_for_each_entry_safe(cl, tmp, &cli_list, list)
+    {
+        if (now - cl->time_alive > timeout || now - cl->time_alive < -timeout) {
+            dawnlog_debug("Ustream client_close: timeout=%d\n", (int)(now - cl->time_alive));
+            client_close(&cl->s.stream);
+        }
+    }
+}
+
 struct network_con_s* tcp_list_contains_address(struct sockaddr_in entry) {
     struct network_con_s *con;
 

src/utils/dawn_uci.c

@@ -79,6 +79,7 @@ struct time_config_s uci_get_time_config() {
         .update_tcp_con = 10,
         .update_chan_util = 5,
         .update_beacon_reports = 20,
+        .client_timeout = 60,
     };
 
     dawnlog_debug_func("Entering...");
@@ -105,6 +106,8 @@ struct time_config_s uci_get_time_config() {
             DAWN_SET_CONFIG_TIME(ret, s, update_chan_util);
             //CONFIG-T: update_beacon_reports|Timer to ask all connected clients for a new BEACON REPORT|[20]
             DAWN_SET_CONFIG_TIME(ret, s, update_beacon_reports);
+            //CONFIG-T: client_timeout|Timespan to check if a client timed out|[60]
+            DAWN_SET_CONFIG_TIME(ret, s, client_timeout);
             return ret;
         }
     }

src/utils/msghandler.c

@@ -656,6 +656,7 @@ enum {
     UCI_UPDATE_TCP_CON,
     UCI_UPDATE_CHAN_UTIL,
     UCI_UPDATE_BEACON_REPORTS,
+    UCI_CLIENT_TIMEOUT,
     __UCI_TIMES_MAX,
 };
 
@@ -713,6 +714,7 @@ static const struct blobmsg_policy uci_times_policy[__UCI_TIMES_MAX] = {
         [UCI_UPDATE_TCP_CON] = {.name = "update_tcp_con", .type = BLOBMSG_TYPE_INT32},
         [UCI_UPDATE_CHAN_UTIL] = {.name = "update_chan_util", .type = BLOBMSG_TYPE_INT32},
         [UCI_UPDATE_BEACON_REPORTS] = {.name = "update_beacon_reports", .type = BLOBMSG_TYPE_INT32},
+        [UCI_CLIENT_TIMEOUT] = {.name = "client_timeout", .type = BLOBMSG_TYPE_INT32},
 };
 
 static void set_uci_item(char* m, struct blob_attr* a)
@@ -895,6 +897,8 @@ static int handle_uci_config(struct blob_attr* msg) {
 
     set_uci_item("dawn.@times[0].update_beacon_reports=%d", tb_times[UCI_UPDATE_BEACON_REPORTS]);
 
+    set_uci_item("dawn.@times[0].client_timeout=%d", tb_times[UCI_CLIENT_TIMEOUT]);
+
     uci_reset();
     dawn_metric = uci_get_dawn_metric();
     timeout_config = uci_get_time_config();

src/utils/ubus.c

@@ -23,6 +23,8 @@ void update_clients(struct uloop_timeout *t);
 
 void update_tcp_connections(struct uloop_timeout *t);
 
+void check_client_timeouts(struct uloop_timeout *t);
+
 void update_channel_utilization(struct uloop_timeout *t);
 
 void run_server_update(struct uloop_timeout *t);
@@ -38,6 +40,9 @@ struct uloop_timeout hostapd_timer = {
 struct uloop_timeout tcp_con_timer = {
         .cb = update_tcp_connections
 };
+struct uloop_timeout client_timeout_timer = {
+        .cb = check_client_timeouts
+};
 struct uloop_timeout channel_utilization_timer = {
         .cb = update_channel_utilization
 };
@@ -1148,11 +1153,20 @@ void update_tcp_connections(struct uloop_timeout *t) {
     uloop_timeout_set(&tcp_con_timer, timeout_config.update_tcp_con * 1000);
 }
 
+void check_client_timeouts(struct uloop_timeout *t) {    
+    dawnlog_debug_func("Entering...");
+
+    check_client_timeout(timeout_config.client_timeout);
+
+    uloop_timeout_set(&client_timeout_timer, CHECK_CLIENT_TIMEOUT * 1000);
+}
+
 void start_tcp_con_update() {
     dawnlog_debug_func("Entering...");
 
     // update connections
     uloop_timeout_add(&tcp_con_timer); // callback = update_tcp_connections
+    uloop_timeout_add(&client_timeout_timer); // callback = client_timeout
 }
 
 void update_hostapd_sockets(struct uloop_timeout *t) {
@@ -1888,6 +1902,7 @@ int uci_send_via_network()
     blobmsg_add_u32(&b, "update_tcp_con", timeout_config.update_tcp_con);
     blobmsg_add_u32(&b, "update_chan_util", timeout_config.update_chan_util);
     blobmsg_add_u32(&b, "update_beacon_reports", timeout_config.update_beacon_reports);
+    blobmsg_add_u32(&b, "client_timeout", timeout_config.client_timeout);
     blobmsg_close_table(&b, times);
 
     send_blob_attr_via_network(b.head, "uci");