net: basic ws handler

includes heartbeat mechanism

1 files changed, 61 insertions, 0 deletions

diff --git a/net/ws.c b/net/ws.c
new file mode 100644
index 0000000..9ad857d
--- /dev/null
+++ b/net/ws.c
@@ -0,0 +1,61 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include <cJSON.h>
+#include <curl/curl.h>
+
+#include <log.h>
+
+extern CURL *ws_handle;
+long last_sequence = -1;
+struct timeval heartbeat_time;
+
+void ws_send_heartbeat()
+{
+    char buf[128] = "{\"op\":1,\"d\":null}";
+    if(last_sequence > 0)
+        snprintf(buf, 128, "{\"op\":1,\"d\":%ld}", last_sequence);
+    size_t sent;
+    curl_ws_send(ws_handle, buf, strnlen(buf, 128), &sent, 0, CURLWS_TEXT);
+
+    struct itimerval itimer;
+    getitimer(ITIMER_REAL, &itimer);
+    if(itimer.it_value.tv_sec < heartbeat_time.tv_sec - 2) {
+        itimer.it_value = heartbeat_time;
+        setitimer(ITIMER_REAL, &itimer, NULL);
+    }
+}
+
+void ws_handle_event(cJSON *event)
+{
+    int op = cJSON_GetObjectItem(event, "op")->valueint;
+    switch(op) {
+    case 1: /* Heartbeat request */
+        ws_send_heartbeat();
+        break;
+    case 10: ; /* Hello */
+        int heartbeat_wait = cJSON_GetObjectItem(cJSON_GetObjectItem(event, "d"), "heartbeat_interval")->valueint;
+        float jitter = (float)rand() / (RAND_MAX * 1.0f);
+
+        heartbeat_time.tv_sec = heartbeat_wait / 1000;
+        heartbeat_time.tv_usec = (heartbeat_wait % 1000) * 1000;
+        struct timeval jitter_time = {
+            .tv_sec = heartbeat_time.tv_sec * jitter,
+            .tv_usec = heartbeat_time.tv_usec * jitter,
+        };
+        struct itimerval new_itimer = {
+            .it_interval = heartbeat_time,
+            .it_value = jitter_time
+        };
+        setitimer(ITIMER_REAL, &new_itimer, NULL);
+        break;
+    case 11:
+        break;
+    default:
+        print(LOG_ERR "ws: received unknown WS opcode %d", op);
+        break;
+    }
+}