GSUP: implement TCAP-like session management
Unlike TCAP/MAP, GSUP is just a transport layer without the
dialogue/context. This prevents us from having session based
communication, required e.g. for USSD. But we can emulate
TCAP dialogue by adding additional IEs, which would allow
to relate each message to a particular session.
This change introduces the following IEs:
- OSMO_GSUP_SESSION_ID_IE,
- OSMO_GSUP_SESSION_STATE_IE,
which optionally can be used to indicate that the message is
related to a session with given ID, and to manage session
state, i.e. initiate, continue, and finish.
Change-Id: I1cee271fed0284a134ffed103c0d4bebbcfde2a8
Related: OS#1597
diff --git a/TODO-RELEASE b/TODO-RELEASE
index 8ccfa49..d984813 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -7,3 +7,5 @@
# If any interfaces have been added since the last public release: c:r:a + 1.
# If any interfaces have been removed or changed since the last public release: c:r:0.
#library what description / commit summary line
+gsup gsup.h the 'osmo_gsup_message' struct extended with
+ session information => ABI changed
diff --git a/include/osmocom/gsm/gsup.h b/include/osmocom/gsm/gsup.h
index a7fa820..5f45699 100644
--- a/include/osmocom/gsm/gsup.h
+++ b/include/osmocom/gsm/gsup.h
@@ -82,6 +82,9 @@
OSMO_GSUP_AUTS_IE = 0x26,
OSMO_GSUP_RES_IE = 0x27,
OSMO_GSUP_CN_DOMAIN_IE = 0x28,
+
+ OSMO_GSUP_SESSION_ID_IE = 0x30,
+ OSMO_GSUP_SESSION_STATE_IE = 0x31,
};
/*! GSUP message type */
@@ -132,6 +135,18 @@
OSMO_GSUP_CN_DOMAIN_CS = 2,
};
+/*! TCAP-like session state */
+enum osmo_gsup_session_state {
+ /*! Undefined session state */
+ OSMO_GSUP_SESSION_STATE_NONE = 0x00,
+ /*! Initiation of a new session */
+ OSMO_GSUP_SESSION_STATE_BEGIN = 0x01,
+ /*! Communication of an existing session */
+ OSMO_GSUP_SESSION_STATE_CONTINUE = 0x02,
+ /*! Indication of the session end */
+ OSMO_GSUP_SESSION_STATE_END = 0x03,
+};
+
/*! parsed/decoded PDP context information */
struct osmo_gsup_pdp_info {
unsigned int context_id;
@@ -176,6 +191,12 @@
enum osmo_gsup_cn_domain cn_domain;
const uint8_t *pdp_charg_enc;
size_t pdp_charg_enc_len;
+
+ /*! Session state \ref osmo_gsup_session_state */
+ enum osmo_gsup_session_state session_state;
+ /*! Unique session identifier and origination flag.
+ * Encoded only when \ref session_state != 0x00 */
+ uint32_t session_id;
};
int osmo_gsup_decode(const uint8_t *data, size_t data_len,
diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index b6ac56d..8663f44 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -385,6 +385,14 @@
gsup_msg->pdp_charg_enc_len = value_len;
break;
+ case OSMO_GSUP_SESSION_ID_IE:
+ gsup_msg->session_id = osmo_decode_big_endian(value, value_len);
+ break;
+
+ case OSMO_GSUP_SESSION_STATE_IE:
+ gsup_msg->session_state = *value;
+ break;
+
default:
LOGP(DLGSUP, LOGL_NOTICE,
"GSUP IE type %d unknown\n", iei);
@@ -564,6 +572,14 @@
gsup_msg->pdp_charg_enc_len, gsup_msg->pdp_charg_enc);
}
+ if ((u8 = gsup_msg->session_state)) {
+ size_t len = sizeof(gsup_msg->session_id);
+ uint8_t *sid = osmo_encode_big_endian(gsup_msg->session_id, len);
+
+ msgb_tlv_put(msg, OSMO_GSUP_SESSION_ID_IE, len, sid);
+ msgb_tlv_put(msg, OSMO_GSUP_SESSION_STATE_IE, sizeof(u8), &u8);
+ }
+
return 0;
}
diff --git a/tests/gsup/gsup_test.c b/tests/gsup/gsup_test.c
index acc7274..6ead7d2 100644
--- a/tests/gsup/gsup_test.c
+++ b/tests/gsup/gsup_test.c
@@ -171,6 +171,15 @@
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
};
+ static const uint8_t dummy_session_ies[] = {
+ 0x2b, /* Dummy value, we only interested in IE coding */
+ TEST_IMSI_IE,
+
+ /* Session ID and state */
+ 0x30, 0x04, 0xde, 0xad, 0xbe, 0xef,
+ 0x31, 0x01, 0x01,
+ };
+
static const struct test {
char *name;
const uint8_t *data;
@@ -204,6 +213,8 @@
send_auth_info_res_umts, sizeof(send_auth_info_res_umts)},
{"Send Authentication Info Request with AUTS and RAND (UMTS)",
send_auth_info_req_auts, sizeof(send_auth_info_req_auts)},
+ {"Dummy message with session IEs",
+ dummy_session_ies, sizeof(dummy_session_ies)},
};
printf("Test GSUP message decoding/encoding\n");
@@ -267,7 +278,7 @@
osmo_hexdump(t->data + j, ie_end - j));
OSMO_ASSERT(j <= ie_end - 2);
- OSMO_ASSERT(t->data[j+0] <= OSMO_GSUP_CN_DOMAIN_IE);
+ OSMO_ASSERT(t->data[j+0] <= OSMO_GSUP_SESSION_STATE_IE);
OSMO_ASSERT(t->data[j+1] <= ie_end - j - 2);
ie_end = j;
diff --git a/tests/gsup/gsup_test.err b/tests/gsup/gsup_test.err
index 05c64fe..5c010e6 100644
--- a/tests/gsup/gsup_test.err
+++ b/tests/gsup/gsup_test.err
@@ -40,6 +40,9 @@
generated message: 08 01 08 21 43 65 87 09 21 43 f5 26 0e 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 20 10 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10
original message: 08 01 08 21 43 65 87 09 21 43 f5 26 0e 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 20 10 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10
IMSI: 123456789012345
+ generated message: 2b 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 01
+ original message: 2b 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 01
+ IMSI: 123456789012345
message 0: tested 11 truncations, 11 parse failures
message 1: tested 14 truncations, 13 parse failures
message 2: tested 83 truncations, 81 parse failures
@@ -54,6 +57,7 @@
message 11: tested 13 truncations, 12 parse failures
message 12: tested 211 truncations, 209 parse failures
message 13: tested 45 truncations, 43 parse failures
+ message 14: tested 20 truncations, 18 parse failures
DLGSUP Stopping DLGSUP logging
message 0: tested 2816 modifications, 510 parse failures
message 1: tested 3584 modifications, 768 parse failures
@@ -69,3 +73,4 @@
message 11: tested 3328 modifications, 767 parse failures
message 12: tested 54016 modifications, 4622 parse failures
message 13: tested 11520 modifications, 1026 parse failures
+ message 14: tested 5120 modifications, 1026 parse failures
diff --git a/tests/gsup/gsup_test.ok b/tests/gsup/gsup_test.ok
index 49a85ba..1f59902 100644
--- a/tests/gsup/gsup_test.ok
+++ b/tests/gsup/gsup_test.ok
@@ -27,4 +27,6 @@
Send Authentication Info Result with IK, CK, AUTN and RES (UMTS) OK
Testing Send Authentication Info Request with AUTS and RAND (UMTS)
Send Authentication Info Request with AUTS and RAND (UMTS) OK
+ Testing Dummy message with session IEs
+ Dummy message with session IEs OK
Done.