sgsn: Create an initial and limited CDR module

This is consuming the new signals and allows to install several
different CDR/observing/event/audit modules in the future. For
getting the bytes in/out the code would have had to undo what the
rate counter is doing and at the same time adding a "total" to
the ratecounter didn't look like a good idea, the same went for
making it a plain counter.

Begin writing the values one by one and open/closing a new FILE
for every log messages. This is not efficient but easily deals
with external truncation/rotation of the file (no fstat for and
checking the links and size). As usual we will wait and see if
this is an issue.

Add some new members to our PDP context structure to see what it
is about.

1 files changed, 5 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index 9e855f8c4..c88a2bbe7 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -207,6 +207,11 @@ struct sgsn_pdp_ctx {
 	struct osmo_timer_list	timer;
 	unsigned int		T;		/* Txxxx number */
 	unsigned int		num_T_exp;	/* number of consecutive T expirations */
+
+	struct osmo_timer_list	cdr_timer;	/* CDR record wird timer */
+	struct timespec		cdr_start;	/* The start of the CDR */
+	uint64_t		cdr_bytes_in;
+	uint64_t		cdr_bytes_out;
 };
 
 #define LOGPDPCTXP(level, pdp, fmt, args...) \