gbproxy: Refactor gb_proxy.c into several files

This patch moves several functions and declarations out of gb_proxy.c
to make them reusable by other components and to separate them by
context and task.

Counter enums (prefix is changed to gbproxy_):
  enum gbprox_global_ctr -> gprs/gb_proxy.h
  enum gbprox_peer_ctr -> gprs/gb_proxy.h

Generic Gb parsing (prefix is changed to gprs_gb_):
  struct gbproxy_parse_context -> openbsc/gprs_gb_parse.h
  gbprox_parse_dtap() -> gprs/gprs_gb_parse.c
  gbprox_parse_llc() -> gprs/gprs_gb_parse.c
  gbprox_parse_bssgp() -> gprs/gprs_gb_parse.c
  gbprox_log_parse_context() -> gprs/gprs_gb_parse.c
  *_shift(), *_match() -> gprs/gprs_gb_parse.c (no prefix)
  gbprox_parse_gmm_* -> gprs/gprs_gb_parse.c (static)
  gbprox_parse_gsm_* -> gprs/gprs_gb_parse.c (static)

MI testing/parsing (prefix gprs_ added):
  is_mi_tmsi() -> gprs/gprs_utils.c
  is_mi_imsi() -> gprs/gprs_utils.c
  parse_mi_tmsi() -> gprs/gprs_utils.c

TLLI state handling (prefix is changed to gbproxy_):
  gbprox_*tlli* -> gprs/gb_proxy_tlli.c
  (except gbprox_patch_tlli, gbproxy_make_sgsn_tlli)

Message patching (prefix is changed to gbproxy_):
  gbprox_*patch* -> gprs/gb_proxy_patch.c
  gbprox_check_imsi -> gprs/gb_proxy_patch.c

Sponsored-by: On-Waves ehf

1 files changed, 39 insertions, 0 deletions

diff --git a/openbsc/src/gprs/gprs_utils.c b/openbsc/src/gprs/gprs_utils.c
index 1a8fa4316..55d4efda1 100644
--- a/openbsc/src/gprs/gprs_utils.c
+++ b/openbsc/src/gprs/gprs_utils.c
@@ -24,6 +24,8 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/gprs/gprs_ns.h>
 
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+
 #include <string.h>
 
 /* FIXME: this needs to go to libosmocore/msgb.c */
@@ -162,3 +164,40 @@ int gprs_str_to_apn(uint8_t *apn_enc, size_t max_len, const char *str)
 	return len;
 }
 
+/* GSM 04.08, 10.5.1.4 */
+int gprs_is_mi_tmsi(const uint8_t *value, size_t value_len)
+{
+	if (value_len != GSM48_TMSI_LEN)
+		return 0;
+
+	if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_TMSI)
+		return 0;
+
+	return 1;
+}
+
+/* GSM 04.08, 10.5.1.4 */
+int gprs_is_mi_imsi(const uint8_t *value, size_t value_len)
+{
+	if (value_len == 0)
+		return 0;
+
+	if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_IMSI)
+		return 0;
+
+	return 1;
+}
+
+int gprs_parse_mi_tmsi(const uint8_t *value, size_t value_len, uint32_t *tmsi)
+{
+	uint32_t tmsi_be;
+
+	if (!gprs_is_mi_tmsi(value, value_len))
+		return 0;
+
+	memcpy(&tmsi_be, value + 1, sizeof(tmsi_be));
+
+	*tmsi = ntohl(tmsi_be);
+	return 1;
+}
+