flow, tcp: Add logging helpers for connection related messages

Most of the messages logged by the TCP code (be they errors, debug or
trace messages) are related to a specific connection / flow.  We're fairly
consistent about prefixing these with the type of connection and the
connection / flow index.  However there are a few places where we put the
index later in the message or omit it entirely.  The template with the
prefix is also a little bulky to carry around for every message,
particularly for spliced connections.

To help keep this consistent, introduce some helpers to log messages
linked to a specific flow.  It takes the flow as a parameter and adds a
uniform prefix to each message.  This makes things slightly neater now, but
more importantly will help keep formatting consistent as we add more things
to the flow table.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/flow.h b/flow.h
index f3dad53..c820a15 100644
--- a/flow.h
+++ b/flow.h
@@ -43,4 +43,18 @@ union flow;
 
 void flow_table_compact(struct ctx *c, union flow *hole);
 
+void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
+	__attribute__((format(printf, 3, 4)));
+
+#define flow_log(f_, pri, ...)	flow_log_(&(f_)->f, (pri), __VA_ARGS__)
+
+#define flow_dbg(f, ...)	flow_log((f), LOG_DEBUG, __VA_ARGS__)
+#define flow_err(f, ...)	flow_log((f), LOG_ERR, __VA_ARGS__)
+
+#define flow_trace(f, ...)						\
+	do {								\
+		if (log_trace)						\
+			flow_dbg((f), __VA_ARGS__);			\
+	} while (0)
+
 #endif /* FLOW_H */