osmocom
/
libosmo-sccp
mirror of https://gerrit.osmocom.org/libosmo-sccp
11
0
Fork 0
Code Issues Releases Wiki Activity

M3UA: Accept DATA without routing context IE if only a single AS in ASP 

There are some M3UA implementations out there who use a routing context
during the ASPAC procedure, but who then don't use it in subsequent DATA
transmission.

This behavior seems to be at the edge of what's possible within the
spec; if you don't configure a routing context, The RCTX IE it is not
required to be sent. And if you have multiple routing contexts/AS within
one ASP, it *must* be sent. But the situation where a routing context
has been configured (but not multiple) is not explicitly covered.

Change-Id: I59f47a999f40411aadc88b8f362d8d2b89a66332
Closes: OS#4594
This commit is contained in:
Harald Welte 2020-06-08 11:15:34 +02:00
parent 3d8605d868
commit deca2bd75e
1 changed files with 49 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
src/m3ua.c
View File

@ -532,9 +532,26 @@ struct m3ua_data_hdr *data_hdr_from_m3ua(struct xua_msg *xua)
return data_hdr;
}
/* if given ASP only has one AS, return that AS */
static struct osmo_ss7_as *find_single_as_for_asp(struct osmo_ss7_asp *asp)
{
struct osmo_ss7_as *as, *as_found = NULL;
llist_for_each_entry(as, &asp->inst->as_list, list) {
if (!osmo_ss7_as_has_asp(as, asp))
continue;
/* check if we already had found another AS within this ASP -> not unique */
if (as_found)
return NULL;
as_found = as;
}
return as_found;
}
static int m3ua_rx_xfer(struct osmo_ss7_asp *asp, struct xua_msg *xua)
{
uint32_t rctx = xua_msg_get_u32(xua, M3UA_IEI_ROUTE_CTX);
struct xua_msg_part *rctx_ie = xua_msg_find_tag(xua, M3UA_IEI_ROUTE_CTX);
struct m3ua_data_hdr *dh;
struct osmo_ss7_as *as;
@ -548,23 +565,33 @@ static int m3ua_rx_xfer(struct osmo_ss7_asp *asp, struct xua_msg *xua)
return M3UA_ERR_UNSUPP_MSG_TYPE;
}
/* Use routing context IE to look up the AS for which the
* message was received. */
as = osmo_ss7_as_find_by_rctx(asp->inst, rctx);
if (!as) {
LOGPASP(asp, DLM3UA, LOGL_ERROR,
"%s(): invalid routing context: %u\n",
__func__, rctx);
return M3UA_ERR_INVAL_ROUT_CTX;
}
if (rctx_ie) {
uint32_t rctx = xua_msg_part_get_u32(rctx_ie);
/* Use routing context IE to look up the AS for which the
* message was received. */
as = osmo_ss7_as_find_by_rctx(asp->inst, rctx);
if (!as) {
LOGPASP(asp, DLM3UA, LOGL_ERROR, "%s(): invalid routing context: %u\n",
__func__, rctx);
return M3UA_ERR_INVAL_ROUT_CTX;
}
/* Verify that this ASP is part of the AS. */
if (!osmo_ss7_as_has_asp(as, asp)) {
LOGPASP(asp, DLM3UA, LOGL_ERROR,
"%s(): This Application Server Process is not part of the AS %s resolved by"
" routing context %u\n",
__func__, (as)->cfg.name, rctx);
return M3UA_ERR_NO_CONFGD_AS_FOR_ASP;
/* Verify that this ASP is part of the AS. */
if (!osmo_ss7_as_has_asp(as, asp)) {
LOGPASP(asp, DLM3UA, LOGL_ERROR,
"%s(): This Application Server Process is not part of the AS %s "
"resolved by routing context %u\n", __func__, (as)->cfg.name, rctx);
return M3UA_ERR_NO_CONFGD_AS_FOR_ASP;
}
} else {
/* no explicit routing context; this only works if there is only one AS in the ASP */
as = find_single_as_for_asp(asp);
if (!as) {
LOGPASP(asp, DLM3UA, LOGL_ERROR,
"%s(): ASP sent M3UA without Routing Context IE but unable to uniquely "
"identify the AS for this message\n", __func__);
return M3UA_ERR_INVAL_ROUT_CTX;
}
}
/* FIXME: check for AS state == ACTIVE */
@ -579,9 +606,11 @@ static int m3ua_rx_xfer(struct osmo_ss7_asp *asp, struct xua_msg *xua)
__func__, xua->mtp.opc, osmo_ss7_pointcode_print(asp->inst, xua->mtp.opc),
xua->mtp.dpc, osmo_ss7_pointcode_print2(asp->inst, xua->mtp.dpc));
/* remove ROUTE_CTX as in the routing case we want to add a new
* routing context on the outbound side */
xua_msg_free_tag(xua, M3UA_IEI_ROUTE_CTX);
if (rctx_ie) {
/* remove ROUTE_CTX as in the routing case we want to add a new
* routing context on the outbound side */
xua_msg_free_tag(xua, M3UA_IEI_ROUTE_CTX);
}
return m3ua_hmdc_rx_from_l2(asp->inst, xua);
/* xua will be freed by caller m3ua_rx_msg() */