lynxis lazus has uploaded this change for review.

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GMM: implement IMEI SV on auth/ciph response

The SGSN is requesting the IMEI SV on an auth/ciphering response.
Parse the answer of the MS/UE.

Change-Id: Ia8b428967a4ce3132a4a63ae10fe610de81c3a29
---
M src/sgsn/gprs_gmm.c
1 file changed, 23 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/osmo-sgsn refs/changes/25/39425/1

diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index b9b13fd..1c457a2 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -637,6 +637,7 @@
 {
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
 	struct gsm48_auth_ciph_resp *acr = (struct gsm48_auth_ciph_resp *)gh->data;
+	struct osmo_mobile_identity mi;
 	struct tlv_parsed tp;
 	struct gsm_auth_tuple *at;
 	const char *res_name = "(no response)";
@@ -673,6 +674,28 @@
 		return -EINVAL;
 	}
 
+	/* IMEI SV parsing */
+	if (TLVP_LEN(&tp, GSM48_IE_GMM_IMEISV) != 9) {
+		LOGMMCTXP(LOGL_ERROR, ctx, "-> GMM AUTH AND CIPH RESPONSE: Invalid IMEISV\n");
+		return -EINVAL;
+	}
+
+	/* FIXME: should we allow invalid IMEI SV? Are there phones which has broken SV in hex? */
+	if (osmo_mobile_identity_decode(&mi,
+					TLVP_VAL(&tp, GSM48_IE_GMM_IMEISV),
+					TLVP_LEN(&tp, GSM48_IE_GMM_IMEISV),
+					false)) {
+		LOGMMCTXP(LOGL_ERROR, ctx, "-> GMM AUTH AND CIPH RESPONSE: Cannot decode IMEISV\n");
+		return -EINVAL;
+	}
+
+	if (mi.type != GSM_MI_TYPE_IMEISV) {
+		LOGMMCTXP(LOGL_ERROR, ctx, "-> GMM AUTH AND CIPH RESPONSE: Invalid MI type found in IMEISV %d\n", mi.type);
+		return -EINVAL;
+	}
+
+	memcpy(&ctx->imei, mi.imeisv, ARRAY_SIZE(ctx->imei));
+
 	/* Start with the good old 4-byte SRES */
 	memcpy(res, TLVP_VAL(&tp, GSM48_IE_GMM_AUTH_SRES), 4);
 	res_len = 4;

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