Change in libosmocore[master]: gsm0808: fix endieness of call identifier

[laforge]

laforge has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/18694 )

Change subject: gsm0808: fix endieness of call identifier
......................................................................

gsm0808: fix endieness of call identifier

The call identifier in the ASSIGNMENT COMMAND is encoded in the wrong
endieness. 3GPP TS 48.008, section 3.2.2.105 specifies that the least
significant byte should be transmitted first, which means that the
endieness here is little endian. Lets make sure that the endieness is
correctly transmitted, regardless of the host byte order.

Change-Id: I6468e502f552f99ab54aec9d4b1c169fdc0adfb8
Related: OS#4582
---
M src/gsm/gsm0808.c
M tests/gsm0808/gsm0808_test.c
2 files changed, 14 insertions(+), 4 deletions(-)

Approvals:
  pespin: Looks good to me, but someone else must approve
  laforge: Looks good to me, approved
  Jenkins Builder: Verified



diff --git a/src/gsm/gsm0808.c b/src/gsm/gsm0808.c
index 23468c3..9fdf379 100644
--- a/src/gsm/gsm0808.c
+++ b/src/gsm/gsm0808.c
@@ -24,6 +24,7 @@
 #include <string.h>
 
 #include <osmocom/core/byteswap.h>
+#include <osmocom/core/endian.h>
 #include <osmocom/gsm/gsm0808.h>
 #include <osmocom/gsm/gsm0808_utils.h>
 #include <osmocom/gsm/protocol/gsm_08_08.h>
@@ -515,7 +516,16 @@
 
 	/* AoIP: Call Identifier 3.2.2.105 */
 	if (ci) {
-		ci_sw = osmo_htonl(*ci);
+		/* NOTE: 3GPP TS 48.008, section 3.2.2.105 specifies that
+		   the least significant byte should be transmitted first.
+		   On x86, this would mean that the endieness is already
+		   correct, however a platform independed implementation
+		   is required: */
+#ifndef OSMO_IS_LITTLE_ENDIAN
+		ci_sw = osmo_swab32(*ci);
+#else
+		ci_sw = *ci;
+#endif
 		msgb_tv_fixed_put(msg, GSM0808_IE_CALL_ID, sizeof(ci_sw),
 				  (uint8_t *) & ci_sw);
 	}
diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c
index d9640aa..5c1a931 100644
--- a/tests/gsm0808/gsm0808_test.c
+++ b/tests/gsm0808/gsm0808_test.c
@@ -438,8 +438,8 @@
 	      0x04, GSM0808_IE_AOIP_TRASP_ADDR, 0x06, 0xc0, 0xa8, 0x64, 0x17,
 	      0x04, 0xd2, GSM0808_IE_SPEECH_CODEC_LIST, 0x07,
 	      GSM0808_SCT_FR3 | 0x50, 0xef, 0xcd, GSM0808_SCT_FR2 | 0xa0, 0x9f,
-	      GSM0808_SCT_CSD | 0x90, 0xc0, GSM0808_IE_CALL_ID, 0xaa, 0xbb,
-	      0xcc, 0xdd };
+	      GSM0808_SCT_CSD | 0x90, 0xc0, GSM0808_IE_CALL_ID, 0xdd, 0xcc,
+	      0xbb, 0xaa };
 
 	struct msgb *msg;
 	struct gsm0808_channel_type ct;
@@ -499,7 +499,7 @@
 		GSM0808_SCT_CSD | 0x90,
 		0xc0,
 		GSM0808_IE_CALL_ID,
-		0xde, 0xad, 0xfa, 0xce, /* CallID */
+		0xce, 0xfa, 0xad, 0xde, /* CallID */		
 		0x83, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, 0x45, /* Kc */
 		GSM0808_IE_GLOBAL_CALL_REF, 0x0d, /* GCR, length */
 		0x03, 0x44, 0x44, 0x44, /* GCR, Net ID */

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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I6468e502f552f99ab54aec9d4b1c169fdc0adfb8
Gerrit-Change-Number: 18694
Gerrit-PatchSet: 4
Gerrit-Owner: dexter <pmaier at sysmocom.de>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: dexter <pmaier at sysmocom.de>
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-Reviewer: pespin <pespin at sysmocom.de>
Gerrit-MessageType: merged
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