From 47aa482bb0094edfc21bbb45dc0f0e8c9c42c521 Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Date: Sun, 7 Jul 2013 13:54:53 +0200
Subject: [PATCH] gsm: Revert the gsm_7bit_encode changes as they are wrong

This reverts commit f996b05dbddccb8e8788dd69777a4fedfa2373eb
and 2b0cac4ef83137ee0bdd583aee877eac467abeab. A detailed
explanation can be found here:

  http://lists.osmocom.org/pipermail/openbsc/2013-July/004737.html

The short description is that:

1.) The API should return (as out parameter) the number of
    octets used.
2.) The handling for the <CR> encoding only applies to USSD
    and it is incomplete. On top of that it broke the SMS test.
---
 src/gsm/gsm0480.c   | 33 +++++++++------------------------
 src/gsm/gsm_utils.c |  6 ------
 2 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 89d43c845..b9b3ed973 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -85,7 +85,7 @@ struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char *
 {
 	struct msgb *msg;
 	uint8_t *seq_len_ptr, *ussd_len_ptr, *data;
-	int len, octet_len;
+	int len;
 
 	msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
 	if (!msg)
@@ -106,13 +106,8 @@ struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char *
 	ussd_len_ptr = msgb_put(msg, 1);
 	data = msgb_put(msg, 0);
 	len = gsm_7bit_encode(data, text);
-	octet_len = len*7/8;
-	if (len*7%8 != 0)
-		octet_len++;
-	/* Warning, len indicates the amount of septets
-	 * (characters), we need amount of octets occupied */
-	msgb_put(msg, octet_len);
-	ussd_len_ptr[0] = octet_len;
+	msgb_put(msg, len);
+	ussd_len_ptr[0] = len;
 	/* USSD-String } */
 
 	/* alertingPattern { */
@@ -132,7 +127,7 @@ struct msgb *gsm0480_create_notifySS(const char *text)
 	struct msgb *msg;
 	uint8_t *data, *tmp_len;
 	uint8_t *seq_len_ptr, *cal_len_ptr, *opt_len_ptr, *nam_len_ptr;
-	int len, octet_len;
+	int len;
 
 	len = strlen(text);
 	if (len < 1 || len > 160)
@@ -178,17 +173,12 @@ struct msgb *gsm0480_create_notifySS(const char *text)
 	tmp_len = msgb_put(msg, 1);
 	data = msgb_put(msg, 0);
 	len = gsm_7bit_encode(data, text);
-	octet_len = len*7/8;
-	if (len*7%8 != 0)
-		octet_len++;
-	/* Warning, len indicates the amount of septets
-	 * (characters), we need amount of octets occupied */
-	tmp_len[0] = octet_len;
-	msgb_put(msg, octet_len);
+	tmp_len[0] = len;
+	msgb_put(msg, len);
 
 	/* }; namePresentationAllowed */
 
-	cal_len_ptr[0] = 3 + 3 + 2 + octet_len;
+	cal_len_ptr[0] = 3 + 3 + 2 + len;
 	opt_len_ptr[0] = cal_len_ptr[0] + 2;
 	/* }; callingName */
 
@@ -425,7 +415,7 @@ struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const
 	struct msgb *msg;
 	struct gsm48_hdr *gh;
 	uint8_t *ptr8;
-	int response_len, octet_len;
+	int response_len;
 
 	msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
 	if (!msg)
@@ -434,12 +424,7 @@ struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const
 	/* First put the payload text into the message */
 	ptr8 = msgb_put(msg, 0);
 	response_len = gsm_7bit_encode(ptr8, text);
-	octet_len = response_len*7/8;
-	if (response_len*7%8 != 0)
-		octet_len++;
-	/* Warning, response_len indicates the amount of septets
-	 * (characters), we need amount of octets occupied */
-	msgb_put(msg, octet_len);
+	msgb_put(msg, response_len);
 
 	/* Then wrap it as an Octet String */
 	msgb_wrap_with_TL(msg, ASN1_OCTET_STRING_TAG);
diff --git a/src/gsm/gsm_utils.c b/src/gsm/gsm_utils.c
index fa77eae40..9569cf32f 100644
--- a/src/gsm/gsm_utils.c
+++ b/src/gsm/gsm_utils.c
@@ -241,12 +241,6 @@ int gsm_septets2octets(uint8_t *result, const uint8_t *rdata, uint8_t septet_len
 		result[z++] = cb;
 		shift++;
 	}
-	/* To avoid the situation where the receiving entity confuses 7 binary
-	 * zero pad bits as the @ character, the carriage return or <CR>
-	 * character (defined in subclause 7.1.1) shall be used for padding in
-	 * this situation. */
-	if (shift == 7)
-		result[z - 1] |= 0x1a;
 
 	free(data);