network: added tcp keepalive support

Signed-off-by: Leonardo Alminana <[email protected]>

include/fluent-bit/flb_network.h

@@ -68,6 +68,18 @@ struct flb_net_setup {
     /* maximum of times a keepalive connection can be used */
     int keepalive_max_recycle;
 
+    /* enable/disable tcp keepalive */
+    int tcp_keepalive;
+
+    /* interval between the last data packet sent and the first TCP keepalive probe */
+    int tcp_keepalive_time;
+
+    /* the interval between TCP keepalive probes */
+    int tcp_keepalive_interval;
+
+    /* number of unacknowledged probes to consider a connection dead */
+    int tcp_keepalive_probes;
+
     /* dns mode : TCP or UDP */
     char *dns_mode;
 
@@ -154,6 +166,7 @@ int flb_net_socket_blocking(flb_sockfd_t fd);
 int flb_net_socket_nonblocking(flb_sockfd_t fd);
 int flb_net_socket_rcv_buffer(flb_sockfd_t fd, int rcvbuf);
 int flb_net_socket_tcp_fastopen(flb_sockfd_t sockfd);
+int flb_net_socket_tcp_keepalive(flb_sockfd_t fd, struct flb_net_setup *net);
 
 /* Socket handling */
 flb_sockfd_t flb_net_socket_create(int family, int nonblock);

src/flb_network.c

@@ -116,6 +116,10 @@ void flb_net_setup_init(struct flb_net_setup *net)
     net->keepalive = FLB_TRUE;
     net->keepalive_idle_timeout = 30;
     net->keepalive_max_recycle = 0;
+    net->tcp_keepalive = FLB_FALSE;
+    net->tcp_keepalive_time = -1;
+    net->tcp_keepalive_interval = -1;
+    net->tcp_keepalive_probes = -1;
     net->accept_timeout = 10;
     net->connect_timeout = 10;
     net->io_timeout = 0; /* Infinite time */
@@ -298,6 +302,51 @@ int flb_net_socket_tcp_fastopen(flb_sockfd_t fd)
     return setsockopt(fd, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen));
 }
 
+
+/*
+ * Enable TCP keepalive
+ */
+int flb_net_socket_tcp_keepalive(flb_sockfd_t fd, struct flb_net_setup *net)
+{
+    int interval;
+    int enabled;
+    int probes;
+    int time;
+    int ret;
+
+    enabled = 1;
+
+    time = net->tcp_keepalive_time;
+    probes = net->tcp_keepalive_probes;
+    interval = net->tcp_keepalive_interval;
+
+    ret = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE,
+                     (const void *) &enabled, sizeof(enabled));
+
+    if (ret == 0 && time >= 0) {
+        ret = setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE,
+                         (const void *) &time, sizeof(time));
+    }
+
+    if (ret == 0 && interval >= 0) {
+        ret = setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL,
+                         (const void *) &interval, sizeof(interval));
+    }
+
+    if (ret == 0 && probes >= 0) {
+        ret = setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT,
+                         (const void *) &probes, sizeof(probes));
+    }
+
+    if (ret != 0) {
+        flb_error("[net] failed to configure TCP keepalive for connection #%i", fd);
+
+        ret = -1;
+    }
+
+    return ret;
+}
+
 flb_sockfd_t flb_net_socket_create(int family, int nonblock)
 {
     flb_sockfd_t fd;