gbproxy: Parse Attach Reject messages

That message is currently ignored but should invalidate the TLLI and
de-register the logical link instead.

This patch extends the parser to recognize such messages and to set
the invalidate_tlli flag.

Sponsored-by: On-Waves ehf

1 files changed, 20 insertions, 0 deletions

diff --git a/openbsc/src/gprs/gprs_gb_parse.c b/openbsc/src/gprs/gprs_gb_parse.c
index 2baaa069c..a0a4469b3 100644
--- a/openbsc/src/gprs/gprs_gb_parse.c
+++ b/openbsc/src/gprs/gprs_gb_parse.c
@@ -219,6 +219,23 @@ static int gprs_gb_parse_gmm_attach_ack(uint8_t *data, size_t data_len,
 	return 1;
 }
 
+static int gprs_gb_parse_gmm_attach_rej(uint8_t *data, size_t data_len,
+					struct gprs_gb_parse_context *parse_ctx)
+{
+	uint8_t *value;
+
+	parse_ctx->llc_msg_name = "ATTACH_REJ";
+
+	/* GMM cause */
+	if (v_fixed_shift(&data, &data_len, 1, &value) <= 0)
+		return 0;
+
+	parse_ctx->invalidate_tlli = 1;
+
+	return 1;
+}
+
+
 static int gprs_gb_parse_gmm_detach_req(uint8_t *data, size_t data_len,
 					struct gprs_gb_parse_context *parse_ctx)
 {
@@ -442,6 +459,9 @@ int gprs_gb_parse_dtap(uint8_t *data, size_t data_len,
 	case GSM48_MT_GMM_ATTACH_REQ:
 		return gprs_gb_parse_gmm_attach_req(data, data_len, parse_ctx);
 
+	case GSM48_MT_GMM_ATTACH_REJ:
+		return gprs_gb_parse_gmm_attach_rej(data, data_len, parse_ctx);
+
 	case GSM48_MT_GMM_ATTACH_ACK:
 		return gprs_gb_parse_gmm_attach_ack(data, data_len, parse_ctx);