support set keepalive interval parameter

Author: andyqzb

src/nc_proxy.c

@@ -359,7 +359,7 @@ proxy_accept(struct context *ctx, struct conn *p)
     }
 
     if (pool->tcpkeepalive) {
-        status = nc_set_tcpkeepalive(c->sd);
+        status = nc_set_tcpkeepalive(c->sd, CLIENT_KEEP_INTERVAL);
         if (status < 0) {
             log_warn("set tcpkeepalive on c %d from p %d failed, ignored: %s",
                      c->sd, p->sd, strerror(errno));

src/nc_proxy.h

@@ -20,6 +20,8 @@
 
 #include <nc_core.h>
 
+#define CLIENT_KEEP_INTERVAL    72
+
 void proxy_ref(struct conn *conn, void *owner);
 void proxy_unref(struct conn *conn);
 void proxy_close(struct context *ctx, struct conn *conn);

src/nc_sentinel.c

@@ -66,7 +66,7 @@ sentinel_connect(struct context *ctx, struct server *sentinel)
     }
 
     /* set keepalive opt on sentinel socket to detect socket dead */
-    status = nc_set_tcpkeepalive(conn->sd);
+    status = nc_set_tcpkeepalive(conn->sd, SENTINEL_KEEP_INTERVAL);
     if (status < 0) {
         log_error("set keepalive on s %d for sentienl server failed: %s",
                   conn->sd, strerror(errno));

src/nc_sentinel.h

@@ -3,6 +3,8 @@
 
 #include <nc_core.h>
 
+#define SENTINEL_KEEP_INTERVAL        30
+
 #define INFO_SENTINEL "info sentinel\r\n"
 #define SUB_SWITCH_REDIRECT "subscribe +switch-master +redirect-to-master\r\n"
 

src/nc_util.c

@@ -110,10 +110,61 @@ nc_set_linger(int sd, int timeout)
 }
 
 int
-nc_set_tcpkeepalive(int sd)
+nc_set_tcpkeepalive(int sd, int interval)
 {
-    int val = 1;
-    return setsockopt(sd, SOL_SOCKET, SO_KEEPALIVE, &val, sizeof(val));
+    int val, status;
+    socklen_t len;
+
+    val = 1;
+    len = sizeof(val);
+    status = setsockopt(sd, SOL_SOCKET, SO_KEEPALIVE, &val, len);
+    if (status == -1)
+    {
+        log_error("setsockopt SO_KEEPALIVE to %d on %d failed: %s",
+                  val, sd, strerror(errno));
+        return status;
+    }
+
+#ifdef __linux__
+    /* Default settings are more or less garbage, with the keepalive time
+     * set to 7200 by default on Linux. Modify settings to make the feature
+     * actually useful. */
+
+    /* Send first probe after interval. */
+    val = interval;
+    status = setsockopt(sd, IPPROTO_TCP, TCP_KEEPIDLE, &val, len);
+    if (status < 0) {
+        log_error("setsockopt TCP_KEEPIDLE to %d on %d failed: %s",
+                  val, sd, strerror(errno));
+        return status;
+    }
+
+    /* Send next probes after the specified interval. Note that we set the
+     * delay as interval / 3, as we send three probes before detecting
+     * an error (see the next setsockopt call). */
+    val = interval/3;
+    if (val == 0) val = 1;
+    status = setsockopt(sd, IPPROTO_TCP, TCP_KEEPINTVL, &val, len);
+    if (status < 0) {
+        log_error("setsockopt TCP_KEEPINTVL to %d on %d failed: %s",
+                  val, sd, strerror(errno));
+        return status;
+    }
+
+    /* Consider the socket in error state after three we send three ACK
+     * probes without getting a reply. */
+    val = 3;
+    status = setsockopt(sd, IPPROTO_TCP, TCP_KEEPCNT, &val, len);
+    if (status < 0) {
+        log_error("setsockopt TCP_KEEPCNT to %d on %d failed: %s",
+                  val, sd, strerror(errno));
+        return status;
+    }
+#else
+    ((void) interval); /* Avoid unused var warning for non Linux systems. */
+#endif
+
+    return 0;
 }
 
 int

src/nc_util.h

@@ -85,7 +85,7 @@ int nc_set_tcpnodelay(int sd);
 int nc_set_linger(int sd, int timeout);
 int nc_set_sndbuf(int sd, int size);
 int nc_set_rcvbuf(int sd, int size);
-int nc_set_tcpkeepalive(int sd);
+int nc_set_tcpkeepalive(int sd, int interval);
 int nc_get_soerror(int sd);
 int nc_get_sndbuf(int sd);
 int nc_get_rcvbuf(int sd);