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nat: Remember if the MSC accepted the connection on principle 

For the USSD module we only want to handle requests that are
legitimate. This is achieved by looking for the CM Service Accept
or the BSSAP CIPHER MODE COMMAND.
This commit is contained in:
Holger Hans Peter Freyther 2011-04-06 11:27:52 +02:00
parent da2f769681
commit ef38e85542
3 changed files with 37 additions and 0 deletions
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1
openbsc/include/openbsc/bsc_nat_sccp.h
View File

@ -77,6 +77,7 @@ struct sccp_connections {
/* status */
int con_type;
int con_local;
int authorized;
int imsi_checked;
char *imsi;

32
openbsc/src/osmo-bsc_nat/bsc_nat.c
View File

@ -525,6 +525,36 @@ send_refuse:
bsc_write(bsc, refuse, IPAC_PROTO_SCCP);
}
/*
* Update the auth status. This can be either a CIPHER MODE COMAMND or
* a CM Serivce Accept. Maybe also LU Accept or such in the future.
*/
static void update_con_authorize(struct sccp_connections *con,
struct bsc_nat_parsed *parsed,
struct msgb *msg)
{
if (!con)
return;
if (con->authorized)
return;
if (parsed->bssap == BSSAP_MSG_BSS_MANAGEMENT &&
parsed->gsm_type == BSS_MAP_MSG_CIPHER_MODE_CMD) {
con->authorized = 1;
} else if (parsed->bssap == BSSAP_MSG_DTAP) {
uint8_t msg_type;
uint32_t len;
struct gsm48_hdr *hdr48;
hdr48 = bsc_unpack_dtap(parsed, msg, &len);
if (!hdr48)
return;
msg_type = hdr48->msg_type & 0xbf;
if (hdr48->proto_discr == GSM48_PDISC_MM &&
msg_type == GSM48_MT_MM_CM_SERV_ACC)
con->authorized = 1;
}
}
static int forward_sccp_to_bts(struct bsc_msc_connection *msc_con, struct msgb *msg)
{
@ -601,6 +631,8 @@ static int forward_sccp_to_bts(struct bsc_msc_connection *msc_con, struct msgb *
return -1;
}
update_con_authorize(con, parsed, msg);
bsc_send_data(con->bsc, msg->l2h, msgb_l2len(msg), proto);
return 0;

4
openbsc/src/osmo-bsc_nat/bsc_ussd.c
View File

@ -318,6 +318,10 @@ int bsc_check_ussd(struct sccp_connections *con, struct bsc_nat_parsed *parsed,
if (!con->imsi)
return 0;
/* We have not verified the IMSI yet */
if (!con->authorized)
return 0;
if (!con->bsc->nat->ussd_lst_name)
return 0;
if (!con->bsc->nat->ussd_query)