[libvirt] [PATCH] Fix max stream packet size for old clients

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

The libvirtd server pushes data out to clients. It does not
know what protocol version the client might have, so must be
conservative and use the old payload limits. ie send no more
than 256kb of data per packet.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 daemon/stream.c          | 2 +-
 src/rpc/virnetprotocol.x | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/daemon/stream.c b/daemon/stream.c
index 87dfaf5..9e36e8a 100644
--- a/daemon/stream.c
+++ b/daemon/stream.c
@@ -708,7 +708,7 @@ daemonStreamHandleRead(virNetServerClientPtr client,
                        daemonClientStream *stream)
 {
     char *buffer;
-    size_t bufferLen = VIR_NET_MESSAGE_PAYLOAD_MAX;
+    size_t bufferLen = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
     int ret;
 
     VIR_DEBUG("client=%p, stream=%p tx=%d closed=%d",
diff --git a/src/rpc/virnetprotocol.x b/src/rpc/virnetprotocol.x
index 131e40b..1eae7cb 100644
--- a/src/rpc/virnetprotocol.x
+++ b/src/rpc/virnetprotocol.x
@@ -50,6 +50,13 @@
  */
 const VIR_NET_MESSAGE_INITIAL = 65536;
 
+/*
+ * Until we enlarged the message buffers, this was the max
+ * payload size. We need to remember this for compat with
+ * old clients.
+ */
+const VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX = 262144;
+
 /* Maximum total message size (serialised). */
 const VIR_NET_MESSAGE_MAX = 16777216;
 
-- 
1.8.3.1