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authorVadim Yanitskiy <axilirator@gmail.com>2018-06-11 03:51:11 +0700
committerVadim Yanitskiy <axilirator@gmail.com>2018-06-11 23:45:48 +0700
commit52e44121dbb6ba278b0fc44a05dc23330457b08e (patch)
tree8c4eef51c1af5b0f4bf233643d73a3a107c16f54
parent11eb4b5add41ec6722fdba2f2023e87543e0507b (diff)
gsm/gsm0480.c: introduce gsm0480_extract_ie_by_tag()
In some cases, there is no need to parse the whole message, e.g. during the conversion from DTAP to GSUP/MAP. This function can be used to extract given IE from a message. Change-Id: I3989d061903352473305f80712f1a1560d05df3d
-rw-r--r--include/osmocom/gsm/gsm0480.h2
-rw-r--r--src/gsm/gsm0480.c88
-rw-r--r--src/gsm/libosmogsm.map1
-rw-r--r--tests/ussd/ussd_test.c75
-rw-r--r--tests/ussd/ussd_test.ok6
5 files changed, 172 insertions, 0 deletions
diff --git a/include/osmocom/gsm/gsm0480.h b/include/osmocom/gsm/gsm0480.h
index b0b6aa29..b31f8a71 100644
--- a/include/osmocom/gsm/gsm0480.h
+++ b/include/osmocom/gsm/gsm0480.h
@@ -91,6 +91,8 @@ struct ss_request {
uint8_t invoke_id;
};
+int gsm0480_extract_ie_by_tag(const struct gsm48_hdr *hdr, uint16_t msg_len,
+ uint8_t **ie, uint16_t *ie_len, uint8_t ie_tag);
int gsm0480_decode_ss_request(const struct gsm48_hdr *hdr, uint16_t len,
struct ss_request *request);
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 5c73e5b8..dfd98773 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -33,6 +33,7 @@
#include <osmocom/gsm/protocol/gsm_04_80.h>
#include <string.h>
+#include <errno.h>
static inline unsigned char *msgb_wrap_with_TL(struct msgb *msgb, uint8_t tag)
{
@@ -214,6 +215,93 @@ static int parse_ss_for_bs_req(const uint8_t *ss_req_data,
uint16_t length,
struct ss_request *req);
+/*! Get pointer to the IE of a given type
+ * \param[in] hdr Pointer to the message starting from header
+ * \param[in] msg_len Length of the whole message + header
+ * \param[out] ie External pointer to be set
+ * \param[out] ie_len External IE length variable
+ * \param[in] ie_tag Tag value of the required IE
+ * \returns 0 in case of success, otherwise -ERRNO
+ *
+ * This function iterates over existing IEs within a given
+ * message (depending on its type), and looks for the one with
+ * given \ref ie_tag value. If the IE is found, the external
+ * pointer pointed by \ref ie will be set to its value part
+ * (omitting TL), and \ref ie_len will be set to the length.
+ * Otherwise, e.g. in case of parsing error, both \ref ie
+ * and \ref ie_len are set to NULL and 0 respectively.
+ */
+int gsm0480_extract_ie_by_tag(const struct gsm48_hdr *hdr, uint16_t msg_len,
+ uint8_t **ie, uint16_t *ie_len, uint8_t ie_tag)
+{
+ uint8_t pdisc, msg_type;
+ uint8_t *tlv, len;
+
+ /* Init external variables */
+ *ie_len = 0;
+ *ie = NULL;
+
+ /* Drop incomplete / corrupted messages */
+ if (msg_len < sizeof(*hdr))
+ return -EINVAL;
+
+ pdisc = gsm48_hdr_pdisc(hdr);
+ msg_type = gsm48_hdr_msg_type(hdr);
+
+ /* Drop non-SS related messages */
+ if (pdisc != GSM48_PDISC_NC_SS)
+ return -EINVAL;
+
+ len = msg_len - sizeof(*hdr);
+ tlv = (uint8_t *) hdr->data;
+
+ /* Parse a message depending on its type */
+ switch (msg_type) {
+ /* See table 2.5: RELEASE COMPLETE message content */
+ case GSM0480_MTYPE_RELEASE_COMPLETE:
+ /* See tables 2.3 and 2.4: REGISTER message content */
+ case GSM0480_MTYPE_REGISTER:
+ /* Iterate over TLV-based IEs */
+ while (len > 2) {
+ if (tlv[0] == ie_tag) {
+ *ie_len = tlv[1];
+ *ie = tlv + 2;
+ return 0;
+ }
+
+ len -= tlv[1] + 2;
+ tlv += tlv[1] + 2;
+ continue;
+ }
+
+ /* The Facility IE is mandatory for REGISTER */
+ if (msg_type == GSM0480_MTYPE_REGISTER)
+ if (ie_tag == GSM0480_IE_FACILITY)
+ return -EINVAL;
+ break;
+
+ /* See table 2.2: FACILITY message content */
+ case GSM0480_MTYPE_FACILITY:
+ /* There is no other IEs */
+ if (ie_tag != GSM0480_IE_FACILITY)
+ break;
+
+ /* Mandatory LV-based Facility IE */
+ if (len < 2)
+ return -EINVAL;
+
+ *ie_len = tlv[0];
+ *ie = tlv + 1;
+ return 0;
+
+ default:
+ /* Wrong message type, out of specs */
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/* Decode a mobile-originated USSD-request message */
int gsm0480_decode_ussd_request(const struct gsm48_hdr *hdr, uint16_t len,
struct ussd_request *req)
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 117cecfa..4aaed46e 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -89,6 +89,7 @@ gsm0480_create_unstructuredSS_Notify;
gsm0480_create_ussd_resp;
gsm0480_create_ussd_notify;
gsm0480_create_ussd_release_complete;
+gsm0480_extract_ie_by_tag;
gsm0480_decode_ussd_request;
gsm0480_decode_ss_request;
gsm0480_wrap_facility;
diff --git a/tests/ussd/ussd_test.c b/tests/ussd/ussd_test.c
index 1f79063b..23fd7393 100644
--- a/tests/ussd/ussd_test.c
+++ b/tests/ussd/ussd_test.c
@@ -34,6 +34,17 @@ static const uint8_t ussd_request[] = {
0x01, 0x7f, 0x01, 0x00
};
+static const uint8_t ussd_facility[] = {
+ 0x1b, 0x3a, 0x12, 0xa2, 0x10, 0x02, 0x01, 0x01,
+ 0x30, 0x0b, 0x02, 0x01, 0x3c, 0x30, 0x06, 0x04,
+ 0x01, 0x0f, 0x04, 0x01, 0x32
+};
+
+static const uint8_t ussd_release[] = {
+ 0x8b, 0x2a, 0x1c, 0x08, 0xa3, 0x06, 0x02, 0x01,
+ 0x05, 0x02, 0x01, 0x24
+};
+
static const uint8_t interrogate_ss[] = {
0x0b, 0x7b, 0x1c, 0x0d, 0xa1, 0x0b, 0x02, 0x01,
0x03, 0x02, 0x01, 0x0e, 0x30, 0x03, 0x04, 0x01,
@@ -116,6 +127,67 @@ static void test_7bit_ussd(const char *text, const char *encoded_hex, const char
}
}
+static void test_extract_ie_by_tag(void)
+{
+ uint16_t ie_len;
+ uint8_t *ie;
+ int rc;
+
+ printf("[i] Testing gsm0480_extract_ie_by_tag()\n");
+
+ /* REGISTER message with Facility IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_request,
+ sizeof(ussd_request), &ie, &ie_len, GSM0480_IE_FACILITY);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie != NULL && ie_len > 0);
+ printf("[?] REGISTER message with Facility IE "
+ "(len=%u): %s\n", ie_len, osmo_hexdump(ie, ie_len));
+
+ /* REGISTER message with SS version IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_request,
+ sizeof(ussd_request), &ie, &ie_len, GSM0480_IE_SS_VERSION);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie != NULL && ie_len > 0);
+ printf("[?] REGISTER message with SS version IE "
+ "(len=%u): %s\n", ie_len, osmo_hexdump(ie, ie_len));
+
+ /* REGISTER message with unknown IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_request,
+ sizeof(ussd_request), &ie, &ie_len, 0xff);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie == NULL && ie_len == 0);
+
+ /* FACILITY message with Facility IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_facility,
+ sizeof(ussd_facility), &ie, &ie_len, GSM0480_IE_FACILITY);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie != NULL && ie_len > 0);
+ printf("[?] FACILITY message with Facility IE "
+ "(len=%u): %s\n", ie_len, osmo_hexdump(ie, ie_len));
+
+ /* FACILITY message with unknown IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_facility,
+ sizeof(ussd_facility), &ie, &ie_len, 0xff);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie == NULL && ie_len == 0);
+
+ /* RELEASE COMPLETE message with Facility IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_release,
+ sizeof(ussd_release), &ie, &ie_len, GSM0480_IE_FACILITY);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie != NULL && ie_len > 0);
+ printf("[?] RELEASE COMPLETE message with Facility IE "
+ "(len=%u): %s\n", ie_len, osmo_hexdump(ie, ie_len));
+
+ /* RELEASE COMPLETE message without Facility IE */
+ rc = gsm0480_extract_ie_by_tag((struct gsm48_hdr *) ussd_release,
+ sizeof(struct gsm48_hdr), &ie, &ie_len, GSM0480_IE_FACILITY);
+ OSMO_ASSERT(rc == 0);
+ OSMO_ASSERT(ie == NULL && ie_len == 0);
+
+ printf("\n");
+}
+
int main(int argc, char **argv)
{
struct ss_request req;
@@ -126,6 +198,9 @@ int main(int argc, char **argv)
osmo_init_logging2(ctx, &info);
+ /* Test gsm0480_extract_ie_by_tag() */
+ test_extract_ie_by_tag();
+
memset(&req, 0, sizeof(req));
gsm0480_decode_ss_request((struct gsm48_hdr *) ussd_request,
sizeof(ussd_request), &req);
diff --git a/tests/ussd/ussd_test.ok b/tests/ussd/ussd_test.ok
index aff383eb..8fa4348f 100644
--- a/tests/ussd/ussd_test.ok
+++ b/tests/ussd/ussd_test.ok
@@ -1,3 +1,9 @@
+[i] Testing gsm0480_extract_ie_by_tag()
+[?] REGISTER message with Facility IE (len=21): a1 13 02 01 03 02 01 3b 30 0b 04 01 0f 04 06 2a d5 4c 16 1b 01
+[?] REGISTER message with SS version IE (len=1): 00
+[?] FACILITY message with Facility IE (len=18): a2 10 02 01 01 30 0b 02 01 3c 30 06 04 01 0f 04 01 32
+[?] RELEASE COMPLETE message with Facility IE (len=8): a3 06 02 01 05 02 01 24
+
Tested if it still works. Text was: **321#
interrogateSS CFU text..'' code 33
Testing parsing a USSD request and truncated versions