19 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.


Refactor diffing same GMM messages

gprs_gmm_attach_req_ies() isn't specific for the attach request.
It also did not cover the full message because of a fixed message length
when comparing both messages.

A diff of the old and new GMM message is required to figure out
if the MS/UE is retransmitting an old message or starting
a new procedure.

Change-Id: Ie698d3a6894a5796663c22c8bfd12b47acda57e6
---
M include/osmocom/sgsn/gprs_gmm.h
M src/sgsn/gprs_gmm.c
M src/sgsn/gprs_gmm_attach.c
3 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/include/osmocom/sgsn/gprs_gmm.h b/include/osmocom/sgsn/gprs_gmm.h
index 6fca77e..900ad6a 100644
--- a/include/osmocom/sgsn/gprs_gmm.h
+++ b/include/osmocom/sgsn/gprs_gmm.h
@@ -45,7 +45,7 @@
 				uint8_t gmm_cause);
 int gsm48_tx_gmm_att_ack(struct sgsn_mm_ctx *mm);
 
-int gprs_gmm_attach_req_ies(struct msgb *a, struct msgb *b);
+int gprs_gmm_msg_cmp(struct msgb *a, struct msgb *b);
 
 int gsm48_gmm_authorize(struct sgsn_mm_ctx *ctx);
 /* TODO: move extract_subscr_* when gsm48_gmm_authorize() got removed */
diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index 7f70260..ea9ffe0 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -1429,25 +1429,18 @@
 	return 0;
 }
 
-/* Checks if two attach request contain the IEs and IE values
+/* Checks if two GMM are the same (required diffing Attach Requests/RAU Requests
  * return 0 if equal
- * return -1 if error
- * return 1 if unequal
- *
- * Only do a simple memcmp for now.
  */
-int gprs_gmm_attach_req_ies(struct msgb *a, struct msgb *b)
+int gprs_gmm_msg_cmp(struct msgb *a, struct msgb *b)
 {
 	struct gsm48_hdr *gh_a = (struct gsm48_hdr *) msgb_gmmh(a);
 	struct gsm48_hdr *gh_b = (struct gsm48_hdr *) msgb_gmmh(b);
 
-#define GMM_ATTACH_REQ_LEN 26
+	if (msgb_l3len(a) != msgb_l3len(b))
+		return 2;
 
-	/* there is the LLC FCS behind */
-	if (msgb_l3len(a) < GMM_ATTACH_REQ_LEN || msgb_l3len(b) < GMM_ATTACH_REQ_LEN)
-		return -1;
-
-	return !!memcmp(gh_a, gh_b, GMM_ATTACH_REQ_LEN);
+	return memcmp(gh_a, gh_b, msgb_l3len(a));
 }
 
 /* 3GPP TS 24.008 § 4.7.4.1 / 9.4.5.2 MO Detach request */
diff --git a/src/sgsn/gprs_gmm_attach.c b/src/sgsn/gprs_gmm_attach.c
index 708ea8f..6331992 100644
--- a/src/sgsn/gprs_gmm_attach.c
+++ b/src/sgsn/gprs_gmm_attach.c
@@ -385,7 +385,7 @@
 			/* 04.08 4.7.3.1.6 d) Abnormal Case
 			 * Only do action if Req IEs differs. */
 			if (ctx->gmm_att_req.attach_req &&
-					gprs_gmm_attach_req_ies(new_attach_req, ctx->gmm_att_req.attach_req)) {
+					gprs_gmm_msg_cmp(new_attach_req, ctx->gmm_att_req.attach_req)) {
 				osmo_fsm_inst_state_chg(fi, ST_INIT, 0, 0);
 				st_init(fi, event, data);
 			}

