[syslog-ng] [PATCH] [logproto.c] "Invalid Frame Header" in syslog protocol

[Gergely Nagy]

When using the syslog protocol, in case when we received an EAGAIN
during an attempt to send the framing, the frame was not resent,
resulting in protocol errors and invalid frame header messages on the
other end.

This patch corrects the problem by not using
log_proto_text_client_post to send framed messages, but a wrapper that
can resume sending the frame too.

Signed-off-by: Fried Zoltan <deirf at balabit.hu>
Signed-off-by: Gergely Nagy <algernon at balabit.hu>
---
 lib/logproto.c |   64 ++++++++++++++++++++++++++++++++++++-------------------
 1 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/lib/logproto.c b/lib/logproto.c
index 16ca0d7..e2cf944 100644
--- a/lib/logproto.c
+++ b/lib/logproto.c
@@ -35,6 +35,26 @@
 #include <sys/uio.h>
 #include <limits.h>
 
+
+typedef struct _LogProtoTextClient
+{
+  LogProto super;
+  guchar *partial;
+  gsize partial_len, partial_pos;
+} LogProtoTextClient;
+
+#define LPFCS_FRAME_INIT    0
+#define LPFCS_FRAME_SEND    1
+#define LPFCS_MESSAGE_SEND  2
+
+typedef struct _LogProtoFramedClient
+{
+  LogProtoTextClient super;
+  gint state;
+  gchar frame_hdr_buf[9];
+  gint frame_hdr_len, frame_hdr_pos;
+} LogProtoFramedClient;
+
 gboolean
 log_proto_set_encoding(LogProto *self, const gchar *encoding)
 {
@@ -70,14 +90,6 @@ log_proto_free(LogProto *s)
   g_free(s);
 }
 
-
-typedef struct _LogProtoTextClient
-{
-  LogProto super;
-  guchar *partial;
-  gsize partial_len, partial_pos;
-} LogProtoTextClient;
-
 static gboolean
 log_proto_text_client_prepare(LogProto *s, gint *fd, GIOCondition *cond)
 {
@@ -144,7 +156,7 @@ log_proto_text_client_flush(LogProto *s)
  * successfully sent this message, or if it should be resent by the caller.
  **/
 static LogProtoStatus
-log_proto_text_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *consumed)
+log_proto_client_post_writer(LogProto *s, guchar *msg, gsize msg_len, gboolean *consumed, gboolean syslog_proto)
 {
   LogProtoTextClient *self = (LogProtoTextClient *) s;
   gint rc;
@@ -173,6 +185,14 @@ log_proto_text_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *co
        */
       return rc;
     }
+  else if (self->partial_len != 0 && !self->partial && syslog_proto)
+  {
+    LogProtoFramedClient *framed_self = (LogProtoFramedClient *) s;
+    self->partial_pos =0;
+    self->partial_len =0;
+    framed_self->state = LPFCS_FRAME_INIT;
+    return rc;
+  }
 
   /* OK, partial buffer empty, now flush msg that we just got */
   
@@ -219,6 +239,18 @@ log_proto_text_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *co
   return LPS_SUCCESS;
 }
 
+static LogProtoStatus
+log_proto_text_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *consumed)
+{
+  return log_proto_client_post_writer(s, msg, msg_len, consumed, FALSE);
+}
+
+static LogProtoStatus
+log_proto_framed_client_post_writer(LogProto *s, guchar *msg, gsize msg_len, gboolean *consumed)
+{
+  return log_proto_client_post_writer(s, msg, msg_len, consumed, TRUE);
+}
+
 LogProto *
 log_proto_text_client_new(LogTransport *transport)
 {
@@ -1741,18 +1773,6 @@ log_proto_dgram_server_new(LogTransport *transport, gint max_msg_size, guint fla
   return &self->super.super;
 }
 
-#define LPFCS_FRAME_INIT    0
-#define LPFCS_FRAME_SEND    1
-#define LPFCS_MESSAGE_SEND  2
-
-typedef struct _LogProtoFramedClient
-{
-  LogProtoTextClient super;
-  gint state;
-  gchar frame_hdr_buf[9];
-  gint frame_hdr_len, frame_hdr_pos;
-} LogProtoFramedClient;
-
 static LogProtoStatus
 log_proto_framed_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *consumed)
 {
@@ -1800,7 +1820,7 @@ log_proto_framed_client_post(LogProto *s, guchar *msg, gsize msg_len, gboolean *
           self->state = LPFCS_MESSAGE_SEND;
         }
     case LPFCS_MESSAGE_SEND:
-      rc = log_proto_text_client_post(s, msg, msg_len, consumed);
+      rc = log_proto_framed_client_post_writer(s, msg, msg_len, consumed);
       
       /* NOTE: we don't check *consumed here, as we might have a pending
        * message in self->partial before we begin, in which case *consumed
-- 
1.7.8.3