diff options
Diffstat (limited to 'openbsc/include/openbsc/msc_ifaces.h')
-rw-r--r-- | openbsc/include/openbsc/msc_ifaces.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/openbsc/include/openbsc/msc_ifaces.h b/openbsc/include/openbsc/msc_ifaces.h new file mode 100644 index 000000000..57d16f4e4 --- /dev/null +++ b/openbsc/include/openbsc/msc_ifaces.h @@ -0,0 +1,40 @@ +#pragma once + +#include <osmocom/core/msgb.h> +#include <openbsc/gsm_data.h> + +/* These are the interfaces of the MSC layer towards (from?) the BSC and RNC, + * i.e. in the direction towards the mobile device (MS aka UE). + * + * 2G will use the A-interface, + * 3G aka UMTS will use the Iu-interface (for the MSC, it's IuCS). + * + * To allow linking parts of the MSC code without having to include entire + * infrastructures of external libraries, the core transmitting and receiving + * functions are left unimplemented. For example, a unit test does not need to + * link against external ASN1 libraries if it is never going to encode actual + * outgoing messages. It is up to each building scope to implement real world + * functions or to plug mere dummy implementations. + * + * For example, msc_tx_dtap(conn, msg), depending on conn->via_iface, will call + * either iu_tx() or a_tx() [note: at time of writing, the A-interface is not + * yet implemented]. When you try to link against libmsc, you will find that + * the compiler complains about an undefined reference to iu_tx(). If you, + * however, link against libiu as well as the osmo-iuh libs (etc.), iu_tx() is + * available. A unit test may instead simply implement a dummy iu_tx() function + * and not link against osmo-iuh. + */ + +/* Each main linkage must implement this function (see comment above). */ +extern int iu_tx(struct msgb *msg, uint8_t sapi); + +/* So far this is a dummy implemented in libmsc/a_iface.c. When A-interface + * gets implemented, it should be in a separate lib (like libiu), this function + * should move there, and the following comment should remain here: " + * Each main linkage must implement this function (see comment above). + * " */ +extern int a_tx(struct msgb *msg); + +int msc_tx_dtap(struct gsm_subscriber_connection *conn, + struct msgb *msg); + |