[PATCH] add keepalive for qemu-nbd

[songlinfeng]

From: songlinfeng <songlinfeng@inspur.com>

we want to export a image with qemu-nbd as server, in client we use libnbd to 
connect qemu-nbd,but when client power down,the server is still working.
qemu-nbd will exit when last client exit.so,we still want server exit when 
client power down.maybe qmp can handle it,but i don't know how to do .
Signed-off-by: songlinfeng <songlinfeng@inspur.com>
---
 qemu-nbd.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 0cd5aa6..115ef2b 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -20,7 +20,8 @@
 #include <getopt.h>
 #include <libgen.h>
 #include <pthread.h>
-
+#include <sys/types.h>
+#include <sys/socket.h>
 #include "qemu/help-texts.h"
 #include "qapi/error.h"
 #include "qemu/cutils.h"
@@ -365,6 +366,26 @@ static void nbd_accept(QIONetListener *listener, 
QIOChannelSocket *cioc,
     nb_fds++;
     nbd_update_server_watch();
     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
+    int tcp_keepalive_intvl = 5;
+    int tcp_keepalive_probes = 5;
+    int tcp_keepalive_time = 60;
+    int tcp_keepalive_on = 1;
+    if (setsockopt(cioc->fd, SOL_TCP, TCP_KEEPINTVL,
+                   &tcp_keepalive_intvl, sizeof(tcp_keepalive_intvl)) < 0) {
+        perror("setsockopt failed\n");
+    }
+    if (setsockopt(cioc->fd, SOL_TCP, TCP_KEEPCNT,
+                   &tcp_keepalive_probes, sizeof(tcp_keepalive_probes)) < 0) {
+        perror("setsockopt failed\n");
+    }
+    if (setsockopt(cioc->fd, SOL_TCP, TCP_KEEPIDLE,
+                   &tcp_keepalive_time, sizeof(tcp_keepalive_time)) < 0) {
+        perror("setsockopt failed\n");
+    }
+    if (setsockopt(cios->fd, SOL_SOCKET, SO_KEEPALIVE,
+                   &tcp_keepalive_on, sizeof(tcp_keepalive_on)) < 0) {
+        perror("setsockopt failed\n");
+    }
 }
 
 static void nbd_update_server_watch(void)
-- 
1.8.3.1