[PATCH] libosmocore[master]: Add function to check GMM encryptability

[Max]

Review at  https://gerrit.osmocom.org/465

Add function to check GMM encryptability

Check if particular GMM message can be encrypted according to 3GPP TS
24.008 § 4.7.1.2

Related: OS#1582
Change-Id: I7ad0e03c2c738d174dd6bc3453f332eeb8da1e7d
---
M include/osmocom/gsm/protocol/gsm_04_08.h
1 file changed, 24 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/65/465/1

diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 074c258..4ee1f6b 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -946,6 +946,30 @@
 	return (hdr->proto_discr & 0xf0) >> 4;
 }
 
+/*! \brief Checks is particular message is cipherable in A/Gb mode according to
+ *         3GPP TS 24.008 § 4.7.1.2
+ *  \param[in] hdr Message header
+ *  \return true if message can be encrypted, false otherwise
+ */
+static inline bool gsm48_hdr_gmm_cipherable(const struct gsm48_hdr *hdr)
+{
+	switch(hdr->msg_type) {
+	case GSM48_MT_GMM_ATTACH_REQ:
+	case GSM48_MT_GMM_ATTACH_REJ:
+	case GSM48_MT_GMM_AUTH_CIPH_REQ:
+	case GSM48_MT_GMM_AUTH_CIPH_RESP:
+	case GSM48_MT_GMM_AUTH_CIPH_REJ:
+	case GSM48_MT_GMM_AUTH_CIPH_FAIL:
+	case GSM48_MT_GMM_ID_REQ:
+	case GSM48_MT_GMM_ID_RESP:
+	case GSM48_MT_GMM_RA_UPD_REQ:
+	case GSM48_MT_GMM_RA_UPD_REJ:
+		return false;
+	default:
+		return true;
+	}
+}
+
 static inline uint8_t gsm48_hdr_trans_id_flip_ti(const struct gsm48_hdr *hdr)
 {
 	return gsm48_hdr_trans_id(hdr) ^ 0x08;

-- 
To view, visit https://gerrit.osmocom.org/465
To unsubscribe, visit https://gerrit.osmocom.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: I7ad0e03c2c738d174dd6bc3453f332eeb8da1e7d
Gerrit-PatchSet: 1
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Owner: Max <msuraev at sysmocom.de>