[arch-projects] [projects][PATCH] wpa_actiond: Wait for three "failed" PONGs before disconnecting

[Emil Velikov]

When the system is very low on resources, select() may return 0 even
when wpa_supplicant is alive and kicking.

Don't disconnect as soon at that occurs - wait three times and clearly
log it.

Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
---
Hi all,

Using [projects] since [wpa_actiond] gets kicked by the email filter.
Can anyone update the message to include a list of supported tags, or 
link to an article/wiki with information?

Back on topic:

This is a small patch I had for 2 months and I thought about getting
upstreamed.

In particular - on certain workloads my system can get really low on
memory (and available fds).

With the patch in place, wpa_actiond no longer kills my connection
although in practise I never seen two consecutive "wpa_supplicant failed
to reply (PONG)" messages.

My patch could be completely bonkers, so any suggestions how to address
this correctly will be appreciated.
---
 wpa_actiond.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/wpa_actiond.c b/wpa_actiond.c
index d60d885..03a9d7f 100644
--- a/wpa_actiond.c
+++ b/wpa_actiond.c
@@ -292,6 +292,7 @@ static void loop(const char *iface, const char *ctrlpath, const int disconnect_t
   /* path to control socket */
   char *ctrlsock = NULL;
   int ctrlsocklen;
+  int pong_failures = 0;
 
   ssid[0] = '\0';
   old_ssid[0] = '\0';
@@ -359,6 +360,7 @@ static void loop(const char *iface, const char *ctrlpath, const int disconnect_t
         }
         logevent(WPA_ACTIOND_LOG_TERMINATE, iface, "");
         state = WPA_ACTIOND_STATE_TERMINATED;
+        pong_failures = 0;
         break;
       case 0:
         if (state == WPA_ACTIOND_STATE_CONNECTION_LOST) {
@@ -372,8 +374,15 @@ static void loop(const char *iface, const char *ctrlpath, const int disconnect_t
             reply_len = 0;
           reply[reply_len] = '\0';
           if(!str_match(reply, "PONG")) {
+            if (pong_failures <= 3) {
+              logevent(WPA_ACTIOND_LOG_CUSTOM_ERROR, iface, "wpa_supplicant failed to reply (PONG)");
+              pong_failures++;
+              break;
+            }
+
             /* supplicant has been terminated */
             if(state == WPA_ACTIOND_STATE_CONNECTED || state == WPA_ACTIOND_STATE_CONNECTION_LOST) {
+              logevent(WPA_ACTIOND_LOG_CUSTOM_ERROR, iface, "wpa_supplicant failed to reply three times in a row - disconnecting");
               logevent(WPA_ACTIOND_LOG_DISCONNECTED, iface, ssid);
               action(WPA_ACTIOND_ACTION_DISCONNECT, iface, ssid, idstr, wpa_ctrl_get_fd(ctrl), script);
             }
@@ -381,6 +390,7 @@ static void loop(const char *iface, const char *ctrlpath, const int disconnect_t
             state = WPA_ACTIOND_STATE_TERMINATED;
           }
         }
+        pong_failures = 0;
         break;
       default:
         /* event received */
@@ -446,6 +456,7 @@ static void loop(const char *iface, const char *ctrlpath, const int disconnect_t
             /* we are not interested in this event */
             break;
         }
+        pong_failures = 0;
     }
   }
 
-- 
2.14.0