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gsm0808: Add utils for Cell Identifier List 

The planned support for true A over IP requires the encoding of
the a Cell Identifier List element (see also BSS_MAP_MSG_PAGING).

This commt adds encoding/decoding functionality and tests for
the element mentioned above, however, it is not yet actively used.

Change-Id: I625245dd1dd396fc2bc189e8cd2c444a33042528
This commit is contained in:
Philipp Maier 2017-03-29 11:35:50 +02:00 committed by Harald Welte
parent 14e76b9958
commit 783047e86e
5 changed files with 181 additions and 0 deletions
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8
include/osmocom/gsm/gsm0808_utils.h
View File

@ -63,3 +63,11 @@ uint8_t gsm0808_enc_encrypt_info(struct msgb *msg,
/* Decode Encryption Information element */
int gsm0808_dec_encrypt_info(struct gsm0808_encrypt_info *ei,
const uint8_t *elem, uint8_t len);
/* Encode Cell Identifier List element */
uint8_t gsm0808_enc_cell_id_list(struct msgb *msg,
const struct gsm0808_cell_id_list *cil);
/* Decode Cell Identifier List element */
int gsm0808_dec_cell_id_list(struct gsm0808_cell_id_list *cil,
const uint8_t *elem, uint8_t len);

8
include/osmocom/gsm/protocol/gsm_08_08.h
View File

@ -457,3 +457,11 @@ struct gsm0808_encrypt_info {
uint8_t key[ENCRY_INFO_KEY_MAXLEN];
unsigned int key_len;
};
/* 3GPP TS 48.008 3.2.2.27 Cell Identifier List */
#define CELL_ID_LIST_LAC_MAXLEN 127
struct gsm0808_cell_id_list {
uint8_t id_discr;
uint16_t id_list_lac[CELL_ID_LIST_LAC_MAXLEN];
unsigned int id_list_len;
};

78
src/gsm/gsm0808_utils.c
View File

@ -450,3 +450,81 @@ int gsm0808_dec_encrypt_info(struct gsm0808_encrypt_info *ei,
return (int)(elem - old_elem);
}
/* Encode Cell Identifier List element */
uint8_t gsm0808_enc_cell_id_list(struct msgb *msg,
const struct gsm0808_cell_id_list *cil)
{
uint8_t *old_tail;
uint8_t *tlv_len;
unsigned int i;
OSMO_ASSERT(msg);
OSMO_ASSERT(cil);
msgb_put_u8(msg, GSM0808_IE_CELL_IDENTIFIER_LIST);
tlv_len = msgb_put(msg, 1);
old_tail = msg->tail;
msgb_put_u8(msg, cil->id_discr & 0x0f);
switch (cil->id_discr) {
case CELL_IDENT_LAC:
OSMO_ASSERT(cil->id_list_len <= CELL_ID_LIST_LAC_MAXLEN)
for (i=0;i<cil->id_list_len;i++) {
msgb_put_u16(msg, cil->id_list_lac[i]);
}
break;
case CELL_IDENT_BSS:
/* Does not have any list items */
break;
default:
/* FIXME: Implement support for all identifier list elements */
OSMO_ASSERT(false);
}
*tlv_len = (uint8_t) (msg->tail - old_tail);
return *tlv_len + 2;
}
/* Decode Cell Identifier List element */
int gsm0808_dec_cell_id_list(struct gsm0808_cell_id_list *cil,
const uint8_t *elem, uint8_t len)
{
uint8_t id_discr;
const uint8_t *old_elem = elem;
unsigned int item_count = 0;
OSMO_ASSERT(cil);
if (!elem)
return -EINVAL;
if (len <= 0)
return -EINVAL;
memset(cil, 0, sizeof(*cil));
id_discr = *elem & 0x0f;
elem++;
len--;
cil->id_discr = id_discr;
switch (id_discr) {
case CELL_IDENT_LAC:
while (len >= 2) {
cil->id_list_lac[item_count] = osmo_load16be(elem);
elem += 2;
item_count++;
len -= 2;
}
case CELL_IDENT_BSS:
/* Does not have any list items */
break;
default:
/* FIXME: Implement support for all identifier list elements */
return -EINVAL;
}
cil->id_list_len = item_count;
return (int)(elem - old_elem);
}

2
src/gsm/libosmogsm.map
View File

@ -150,6 +150,8 @@ gsm0808_enc_channel_type;
gsm0808_dec_channel_type;
gsm0808_enc_encrypt_info;
gsm0808_dec_encrypt_info;
gsm0808_enc_cell_id_list;
gsm0808_dec_cell_id_list;
gsm0858_rsl_ul_meas_enc;

85
tests/gsm0808/gsm0808_test.c
View File

@ -610,6 +610,88 @@ static void test_gsm0808_enc_dec_encrypt_info()
msgb_free(msg);
}
static void test_gsm0808_enc_dec_cell_id_list_lac()
{
struct gsm0808_cell_id_list enc_cil;
struct gsm0808_cell_id_list dec_cil;
struct msgb *msg;
uint8_t rc_enc;
int rc_dec;
memset(&enc_cil, 0, sizeof(enc_cil));
enc_cil.id_discr = CELL_IDENT_LAC;
enc_cil.id_list_lac[0] = 0x0124;
enc_cil.id_list_lac[1] = 0xABCD;
enc_cil.id_list_lac[2] = 0x5678;
enc_cil.id_list_len = 3;
msg = msgb_alloc(1024, "output buffer");
rc_enc = gsm0808_enc_cell_id_list(msg, &enc_cil);
OSMO_ASSERT(rc_enc == 9);
rc_dec = gsm0808_dec_cell_id_list(&dec_cil, msg->data + 2,
msg->len - 2);
OSMO_ASSERT(rc_dec == 7);
OSMO_ASSERT(memcmp(&enc_cil, &dec_cil, sizeof(enc_cil)) == 0);
msgb_free(msg);
}
static void test_gsm0808_enc_dec_cell_id_list_single_lac()
{
struct gsm0808_cell_id_list enc_cil;
struct gsm0808_cell_id_list dec_cil;
struct msgb *msg;
uint8_t cil_enc_expected[] = { GSM0808_IE_CELL_IDENTIFIER_LIST, 0x03,
0x05, 0x23, 0x42
};
uint8_t rc_enc;
int rc_dec;
memset(&enc_cil, 0, sizeof(enc_cil));
enc_cil.id_discr = CELL_IDENT_LAC;
enc_cil.id_list_lac[0] = 0x2342;
enc_cil.id_list_len = 1;
msg = msgb_alloc(1024, "output buffer");
rc_enc = gsm0808_enc_cell_id_list(msg, &enc_cil);
OSMO_ASSERT(rc_enc == 5);
OSMO_ASSERT(memcmp(cil_enc_expected, msg->data, msg->len) == 0);
rc_dec = gsm0808_dec_cell_id_list(&dec_cil, msg->data + 2,
msg->len - 2);
OSMO_ASSERT(rc_dec == 3);
OSMO_ASSERT(memcmp(&enc_cil, &dec_cil, sizeof(enc_cil)) == 0);
msgb_free(msg);
}
static void test_gsm0808_enc_dec_cell_id_list_bss()
{
struct gsm0808_cell_id_list enc_cil;
struct gsm0808_cell_id_list dec_cil;
struct msgb *msg;
uint8_t rc_enc;
int rc_dec;
memset(&enc_cil, 0, sizeof(enc_cil));
enc_cil.id_discr = CELL_IDENT_LAC;
msg = msgb_alloc(1024, "output buffer");
rc_enc = gsm0808_enc_cell_id_list(msg, &enc_cil);
OSMO_ASSERT(rc_enc == 3);
rc_dec = gsm0808_dec_cell_id_list(&dec_cil, msg->data + 2,
msg->len - 2);
OSMO_ASSERT(rc_dec == 1);
OSMO_ASSERT(memcmp(&enc_cil, &dec_cil, sizeof(enc_cil)) == 0);
msgb_free(msg);
}
int main(int argc, char **argv)
{
printf("Testing generation of GSM0808 messages\n");
@ -637,6 +719,9 @@ int main(int argc, char **argv)
test_gsm0808_enc_dec_speech_codec_list();
test_gsm0808_enc_dec_channel_type();
test_gsm0808_enc_dec_encrypt_info();
test_gsm0808_enc_dec_cell_id_list_lac();
test_gsm0808_enc_dec_cell_id_list_single_lac();
test_gsm0808_enc_dec_cell_id_list_bss();
printf("Done\n");
return EXIT_SUCCESS;