sysmobts: Fix the function check_oml_msg of utils

This patch allows check the oml message correctly.
I have splitted the function in three different, one for
checking the manufacturer label ID, another for checking the
FOM and the principal which will call to the other function
for checking the OM header and all the part that I have told
before of the OML message received.

Signed-off-by: Alvaro Neira Ayuso <anayuso@sysmocom.de>

1 files changed, 63 insertions, 49 deletions

diff --git a/src/osmo-bts-sysmo/utils.c b/src/osmo-bts-sysmo/utils.c
index 01e6f973..f867a424 100644
--- a/src/osmo-bts-sysmo/utils.c
+++ b/src/osmo-bts-sysmo/utils.c
@@ -160,6 +160,53 @@ void prepend_oml_ipa_header(struct msgb *msg)
 	hh->len = htons(msg->len - sizeof(struct ipaccess_head));
 }
 
+static int check_oml_fom(struct abis_om_hdr *omh, size_t len)
+{
+	if (omh->length != len) {
+		LOGP(DL1C, LOGL_ERROR, "Incorrect om length value %d %d\n",
+		     omh->length, len);
+		return -1;
+	}
+
+	if (len < sizeof(struct abis_om_fom_hdr)) {
+		LOGP(DL1C, LOGL_ERROR, "Fom header insufficient space %d %d\n",
+		     len, sizeof(struct abis_om_fom_hdr));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int check_oml_manuf(struct abis_om_hdr *hdr, size_t msg_size)
+{
+	if (msg_size < 1) {
+		LOGP(DL1C, LOGL_ERROR, "No ManId Length Indicator %d\n",
+		     msg_size);
+		return -1;
+	}
+
+	if (hdr->data[0] >= msg_size - 1) {
+		LOGP(DL1C, LOGL_ERROR,
+		     "Insuficient message space for this ManId Lenght %d %d\n",
+		     hdr->data[0], msg_size - 1);
+		return -1;
+	}
+
+	if (hdr->data[0] == sizeof(ipaccess_magic) &&
+	    strncmp(ipaccess_magic, (const char *)hdr->data + 1,
+		    sizeof(ipaccess_magic)) == 0) {
+		return OML_MSG_TYPE_IPA;
+	} else if (hdr->data[0] == sizeof(osmocom_magic) &&
+		   strncmp(osmocom_magic, (const char *) hdr->data + 1,
+			   sizeof(osmocom_magic)) == 0) {
+		return OML_MSG_TYPE_OSMO;
+	} else {
+		LOGP(DL1C, LOGL_ERROR,
+		     "Manuf Label Unknown\n");
+		return -1;
+	}
+}
+
 /**
  * \brief Check that the data in \param msg is a proper OML message
  *
@@ -182,14 +229,11 @@ void prepend_oml_ipa_header(struct msgb *msg)
 int check_oml_msg(struct msgb *msg)
 {
 	struct abis_om_hdr *omh;
-	int abis_oml_hdr_len;
-	char label_id[255];
+	int ret = OML_MSG_TYPE_ETSI;
 
-	abis_oml_hdr_len = sizeof(struct abis_om_hdr);
-
-	if (msg->len < abis_oml_hdr_len) {
+	if (msg->len < sizeof(*omh)) {
 		LOGP(DL1C, LOGL_ERROR, "Om header insufficient space %d %d\n",
-		     msg->len, abis_oml_hdr_len);
+		     msg->len, sizeof(*omh));
 		return -1;
 	}
 
@@ -216,54 +260,24 @@ int check_oml_msg(struct msgb *msg)
 		return -1;
 	}
 
-	if (omh->length != sizeof(struct abis_om_fom_hdr)) {
-		LOGP(DL1C, LOGL_ERROR, "Incorrect om length value %d %d\n",
-		     omh->length, sizeof(struct abis_om_fom_hdr));
-		return -1;
-	}
-
-	if (omh->mdisc == ABIS_OM_MDISC_MANUF) {
-		abis_oml_hdr_len += sizeof(ipaccess_magic);
-
-		if (msg->len < abis_oml_hdr_len) {
-			LOGP(DL1C, LOGL_ERROR,
-			     "ID manuf label insufficient space %d %d\n",
-			     msg->len, abis_oml_hdr_len);
-			return -1;
-		}
-	}
+	if (omh->mdisc == ABIS_OM_MDISC_MANUF)
+		ret = check_oml_manuf(omh, msgb_l2len(msg) - sizeof(*omh));
 
-	abis_oml_hdr_len += sizeof(struct abis_om_fom_hdr);
+	if (ret == OML_MSG_TYPE_OSMO)
+		msg->l3h = omh->data + sizeof(osmocom_magic) + 1;
+	else if (ret == OML_MSG_TYPE_IPA)
+		msg->l3h = omh->data + sizeof(ipaccess_magic) + 1;
+	else if (ret == OML_MSG_TYPE_ETSI)
+		msg->l3h = omh->data;
+	else
+		msg->l3h = NULL;
 
-	if (msg->len < abis_oml_hdr_len) {
-		LOGP(DL1C, LOGL_ERROR, "Fom header insufficient space %d %d\n",
-		     msg->len, abis_oml_hdr_len);
+	if (ret < 0)
 		return -1;
-	}
 
-	msg->l3h = msg->data + sizeof(struct abis_om_hdr);
-
-	if (omh->mdisc == ABIS_OM_MDISC_MANUF) {
-		strncpy(label_id, (const char *) msg->l3h + 1,
-			sizeof(ipaccess_magic));
-
-		if (strncmp(ipaccess_magic, label_id,
-			    sizeof(ipaccess_magic)) == 0) {
-			msg->l3h = msg->l3h + sizeof(ipaccess_magic) + 1;
-			return OML_MSG_TYPE_IPA;
-		} else if (strncmp(osmocom_magic, label_id,
-				 sizeof(osmocom_magic)) == 0) {
-			msg->l3h = msg->l3h + sizeof(osmocom_magic) + 1;
-			return OML_MSG_TYPE_OSMO;
-		} else {
-			msg->l3h = NULL;
-			LOGP(DL1C, LOGL_ERROR,
-			     "Manuf Label Unknown %s\n", label_id);
-			return -1;
-		}
-	}
+	check_oml_fom(omh, msgb_l3len(msg));
 
-	return OML_MSG_TYPE_ETSI;
+	return ret;
 }
 
 int check_ipa_header(struct msgb *msg)