[Qemu-devel] [PATCH v3] qapi: Add InetSocketAddress member keep-alive

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

It's needed to provide keepalive for nbd client to track server
availability.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

v3: [by Markus's comments]

- Fix commit subject
- Add comment to qapi and restrict server-side connections
- Fix s/"keep-alive="/",keep-alive"/


 qapi/sockets.json   |  6 +++++-
 util/qemu-sockets.c | 28 ++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/qapi/sockets.json b/qapi/sockets.json
index fc81d8d5e8..c44af481a1 100644
--- a/qapi/sockets.json
+++ b/qapi/sockets.json
@@ -53,6 +53,9 @@
 #
 # @ipv6: whether to accept IPv6 addresses, default try both IPv4 and IPv6
 #
+# @keep-alive: enable keep-alive when connecting to this socket. Not supported
+#              for server-side connections. (Since 4.1)
+#
 # Since: 1.3
 ##
 { 'struct': 'InetSocketAddress',
@@ -61,7 +64,8 @@
     '*numeric':  'bool',
     '*to': 'uint16',
     '*ipv4': 'bool',
-    '*ipv6': 'bool' } }
+    '*ipv6': 'bool',
+    '*keep-alive': 'bool' } }
 
 ##
 # @UnixSocketAddress:
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 8850a280a8..813063761b 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -438,6 +438,12 @@ int inet_connect_saddr(InetSocketAddress *saddr, Error **errp)
     struct addrinfo *res, *e;
     int sock = -1;
 
+    if (saddr->keep_alive) {
+        error_setg(errp, "keep-alive options is not supported for server-side "
+                   "connection");
+        return -1;
+    }
+
     res = inet_parse_connect_saddr(saddr, errp);
     if (!res) {
         return -1;
@@ -457,6 +463,19 @@ int inet_connect_saddr(InetSocketAddress *saddr, Error **errp)
     }
 
     freeaddrinfo(res);
+
+    if (saddr->keep_alive) {
+        int val = 1;
+        int ret = qemu_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
+                                  &val, sizeof(val));
+
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "Unable to set KEEPALIVE");
+            close(sock);
+            return -1;
+        }
+    }
+
     return sock;
 }
 
@@ -652,6 +671,15 @@ int inet_parse(InetSocketAddress *addr, const char *str, Error **errp)
         }
         addr->has_ipv6 = true;
     }
+    begin = strstr(optstr, ",keep-alive");
+    if (begin) {
+        if (inet_parse_flag("keep-alive", begin + strlen(",keep-alive"),
+                            &addr->keep_alive, errp) < 0)
+        {
+            return -1;
+        }
+        addr->has_keep_alive = true;
+    }
     return 0;
 }
 
-- 
2.18.0