nat: Simplify the code and call auth_imsi from the main method
Do the auth check in bsc_nat_filter_sccp_cr, remove the cause from
the signature again. For the bsc_nat_filter_dt restructure the flow
but leave the auth inside the id response message.
Return 1 when the IMSI has been extracted as indicator for running
the auth check. 1 has not been used before and is safe to be used
as this indicator.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
index f290e2d..e3e63d1 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
@@ -99,7 +99,7 @@
static int _cr_check_loc_upd(struct bsc_connection *bsc,
uint8_t *data, unsigned int length,
- char **imsi, struct bsc_nat_reject_cause *cause)
+ char **imsi)
{
uint8_t mi_type;
struct gsm48_loc_upd_req *lu;
@@ -123,13 +123,12 @@
gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
*imsi = talloc_strdup(bsc, mi_string);
- return auth_imsi(bsc, mi_string, cause);
+ return 1;
}
static int _cr_check_cm_serv_req(struct bsc_connection *bsc,
uint8_t *data, unsigned int length,
- int *con_type, char **imsi,
- struct bsc_nat_reject_cause *cause)
+ int *con_type, char **imsi)
{
static const uint32_t classmark_offset =
offsetof(struct gsm48_service_request, classmark);
@@ -162,12 +161,11 @@
return 0;
*imsi = talloc_strdup(bsc, mi_string);
- return auth_imsi(bsc, mi_string, cause);
+ return 1;
}
static int _cr_check_pag_resp(struct bsc_connection *bsc,
- uint8_t *data, unsigned int length,
- char **imsi, struct bsc_nat_reject_cause *cause)
+ uint8_t *data, unsigned int length, char **imsi)
{
struct gsm48_pag_resp *resp;
char mi_string[GSM48_MI_SIZE];
@@ -189,7 +187,7 @@
return 0;
*imsi = talloc_strdup(bsc, mi_string);
- return auth_imsi(bsc, mi_string, cause);
+ return 1;
}
static int _dt_check_id_resp(struct bsc_connection *bsc,
@@ -199,7 +197,6 @@
{
char mi_string[GSM48_MI_SIZE];
uint8_t mi_type;
- int ret;
if (length < 2) {
LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n");
@@ -217,10 +214,9 @@
if (mi_type != GSM_MI_TYPE_IMSI)
return 0;
- ret = auth_imsi(bsc, mi_string, cause);
con->imsi_checked = 1;
con->imsi = talloc_strdup(con, mi_string);
- return ret;
+ return auth_imsi(bsc, mi_string, cause);
}
@@ -232,7 +228,7 @@
struct tlv_parsed tp;
struct gsm48_hdr *hdr48;
int hdr48_len;
- int len;
+ int len, ret = 0;
uint8_t msg_type, proto;
*con_type = NAT_CON_TYPE_NONE;
@@ -278,24 +274,35 @@
if (proto == GSM48_PDISC_MM &&
msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
*con_type = NAT_CON_TYPE_LU;
- return _cr_check_loc_upd(bsc, &hdr48->data[0],
- hdr48_len - sizeof(*hdr48), imsi, cause);
+ ret = _cr_check_loc_upd(bsc, &hdr48->data[0],
+ hdr48_len - sizeof(*hdr48), imsi);
} else if (proto == GSM48_PDISC_MM &&
msg_type == GSM48_MT_MM_CM_SERV_REQ) {
*con_type = NAT_CON_TYPE_CM_SERV_REQ;
- return _cr_check_cm_serv_req(bsc, &hdr48->data[0],
+ ret = _cr_check_cm_serv_req(bsc, &hdr48->data[0],
hdr48_len - sizeof(*hdr48),
- con_type, imsi, cause);
+ con_type, imsi);
} else if (proto == GSM48_PDISC_RR &&
msg_type == GSM48_MT_RR_PAG_RESP) {
*con_type = NAT_CON_TYPE_PAG_RESP;
- return _cr_check_pag_resp(bsc, &hdr48->data[0],
- hdr48_len - sizeof(*hdr48), imsi, cause);
+ ret = _cr_check_pag_resp(bsc, &hdr48->data[0],
+ hdr48_len - sizeof(*hdr48), imsi);
} else {
/* We only want to filter the above, let other things pass */
*con_type = NAT_CON_TYPE_OTHER;
return 0;
}
+
+ /* check if we are done */
+ if (ret != 1)
+ return ret;
+
+ /* the memory allocation failed */
+ if (!*imsi)
+ return -1;
+
+ /* now check the imsi */
+ return auth_imsi(bsc, *imsi, cause);
}
int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
@@ -322,11 +329,9 @@
proto = hdr48->proto_discr & 0x0f;
msg_type = hdr48->msg_type & 0xbf;
- if (proto == GSM48_PDISC_MM &&
- msg_type == GSM48_MT_MM_ID_RESP) {
- return _dt_check_id_resp(bsc, &hdr48->data[0],
- len - sizeof(*hdr48), con, cause);
- } else {
+ if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP)
return 0;
- }
+
+ return _dt_check_id_resp(bsc, &hdr48->data[0],
+ len - sizeof(*hdr48), con, cause);
}