From 5a7740d1dbefcb0116a1936da3f96960250fd849 Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@gnumonks.org>
Date: Wed, 1 Aug 2018 17:29:48 +0200
Subject: [PATCH] re-introduce ipa_ccm_idtag_parse_off()

In the previous commit we deprecated ipa_ccm_idtag_parse() but
also removed ipa_ccm_idtag_parse_off(), for which I couldn't find
any users.  However, legacy openbsc.git still uses this function,
so let's re-introiduce it in its original form.

Change-Id: Ibfe53b04340eb355c8bfb8453a2af1522a4b6baf
---
 include/osmocom/gsm/ipa.h |  5 ++---
 src/gsm/ipa.c             | 16 +++++++++++++---
 src/gsm/libosmogsm.map    |  1 +
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/include/osmocom/gsm/ipa.h b/include/osmocom/gsm/ipa.h
index ec143d0e9..93cb1bf1d 100644
--- a/include/osmocom/gsm/ipa.h
+++ b/include/osmocom/gsm/ipa.h
@@ -28,6 +28,8 @@ const char *ipa_ccm_idtag_name(uint8_t tag);
 
 int ipa_ccm_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
 	OSMO_DEPRECATED("Use ipa_ccm_id_{get,resp}_parse instead");
+int ipa_ccm_idtag_parse_off(struct tlv_parsed *dec, unsigned char *buf, int len, const int len_offset)
+	OSMO_DEPRECATED("Use ipa_ccm_id_{get,resp}_parse instead");
 
 /* parse payload of IPA CCM ID GET into a osmocom TLV style representation */
 int ipa_ccm_id_get_parse(struct tlv_parsed *dec, const uint8_t *buf, unsigned int len);
@@ -35,9 +37,6 @@ int ipa_ccm_id_get_parse(struct tlv_parsed *dec, const uint8_t *buf, unsigned in
 /* parse payload of IPA CCM ID RESP into a osmocom TLV style representation */
 int ipa_ccm_id_resp_parse(struct tlv_parsed *dec, const uint8_t *buf, unsigned int len);
 
-/* Is the TAG included in the length field? */
-int ipa_ccm_idtag_parse_off(struct tlv_parsed *dec, unsigned char *buf, int len, const int len_offset);
-
 /* parse an Unit ID in string format into the 'ipaccess_unit' data structure */
 int ipa_parse_unitid(const char *str, struct ipaccess_unit *unit_data);
 
diff --git a/src/gsm/ipa.c b/src/gsm/ipa.c
index 3c7c300b3..508cc13da 100644
--- a/src/gsm/ipa.c
+++ b/src/gsm/ipa.c
@@ -99,6 +99,11 @@ const char *ipa_ccm_idtag_name(uint8_t tag)
 }
 
 int ipa_ccm_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
+{
+	return ipa_ccm_idtag_parse_off(dec, buf, len, 0);
+}
+
+int ipa_ccm_idtag_parse_off(struct tlv_parsed *dec, unsigned char *buf, int len, const int len_offset)
 {
 	uint8_t t_len;
 	uint8_t t_tag;
@@ -111,6 +116,11 @@ int ipa_ccm_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
 		t_len = *cur++;
 		t_tag = *cur++;
 
+		if (t_len < len_offset) {
+			LOGP(DLMI, LOGL_ERROR, "minimal offset not included: %d < %d\n", t_len, len_offset);
+			return -EINVAL;
+		}
+
 		if (t_len > len + 1) {
 			LOGP(DLMI, LOGL_ERROR, "The tag does not fit: %d > %d\n", t_len, len + 1);
 			return -EINVAL;
@@ -118,11 +128,11 @@ int ipa_ccm_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
 
 		DEBUGPC(DLMI, "%s='%s' ", ipa_ccm_idtag_name(t_tag), cur);
 
-		dec->lv[t_tag].len = t_len;
+		dec->lv[t_tag].len = t_len - len_offset;
 		dec->lv[t_tag].val = cur;
 
-		cur += t_len;
-		len -= t_len;
+		cur += t_len - len_offset;
+		len -= t_len - len_offset;
 	}
 	return 0;
 }
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index a1d342aa7..2bb9d97cc 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -461,6 +461,7 @@ ipa_ccm_send_pong;
 ipa_ccm_tlv_to_unitdata;
 ipa_ccm_idtag_name;
 ipa_ccm_idtag_parse;
+ipa_ccm_idtag_parse_off;
 ipa_ccm_id_get_parse;
 ipa_ccm_id_resp_parse;
 ipa_ccm_make_id_resp;