telemetry: add upper limit on connections

This patch limits the number of client connections to the new telemetry
socket. The limit is set to 10.

Signed-off-by: Ciara Power <ciara.power@intel.com>

diff --git a/lib/librte_telemetry/telemetry.c b/lib/librte_telemetry/telemetry.c
index e7e3d86..0252282 100644 (file)
--- a/lib/librte_telemetry/telemetry.c
+++ b/lib/librte_telemetry/telemetry.c
@@ -23,6 +23,7 @@
 #define MAX_CMD_LEN 56
 #define MAX_HELP_LEN 64
 #define MAX_OUTPUT_LEN (1024 * 16)
+#define MAX_CONNECTIONS 10
 
 static void *
 client_handler(void *socket);
@@ -37,6 +38,7 @@ struct socket {
        int sock;
        char path[sizeof(((struct sockaddr_un *)0)->sun_path)];
        handler fn;
+       uint16_t *num_clients;
 };
 static struct socket v2_socket; /* socket for v2 telemetry */
 static struct socket v1_socket; /* socket for v1 telemetry */
@@ -46,6 +48,7 @@ static struct cmd_callback callbacks[TELEMETRY_MAX_CALLBACKS];
 static int num_callbacks; /* How many commands are registered */
 /* Used when accessing or modifying list of command callbacks */
 static rte_spinlock_t callback_sl = RTE_SPINLOCK_INITIALIZER;
+static uint16_t v2_clients;
 
 int
 rte_telemetry_register_cmd(const char *cmd, telemetry_cb fn, const char *help)
@@ -263,6 +266,7 @@ client_handler(void *sock_id)
                bytes = read(s, buffer, sizeof(buffer) - 1);
        }
        close(s);
+       __atomic_sub_fetch(&v2_clients, 1, __ATOMIC_RELAXED);
        return NULL;
 }
 
@@ -279,6 +283,16 @@ socket_listener(void *socket)
                                "Error with accept, telemetry thread quitting");
                        return NULL;
                }
+               if (s->num_clients != NULL) {
+                       uint16_t conns = __atomic_load_n(s->num_clients,
+                                       __ATOMIC_RELAXED);
+                       if (conns >= MAX_CONNECTIONS) {
+                               close(s_accepted);
+                               continue;
+                       }
+                       __atomic_add_fetch(s->num_clients, 1,
+                                       __ATOMIC_RELAXED);
+               }
                pthread_create(&th, NULL, s->fn, (void *)(uintptr_t)s_accepted);
                pthread_detach(th);
        }
@@ -373,6 +387,7 @@ telemetry_v2_init(const char *runtime_dir, rte_cpuset_t *cpuset)
 {
        pthread_t t_new;
 
+       v2_socket.num_clients = &v2_clients;
        rte_telemetry_register_cmd("/", list_commands,
                        "Returns list of available commands, Takes no parameters");
        rte_telemetry_register_cmd("/info", json_info,