add simplistic IuUP FSM and strip/add IuUP headers
This should really be using the FSM in libosmocore/laforge/iu_up: take the best
of both sides and integate in the libosmocore FSM implementation, then use it
here.
- in libosmocore, the FSM definition is nicer.
- here, we have correct header checksums.
Introduce using msgb to receive, pass and send RTP packets.
Add/strip IuUP from RTP data (for which msgb is particularly useful).
The payload type on an IuUP conn is maintained as negotiated in the IuUP
Initialization. For the pure RTP side, an SDP "AMR" ptmap attribute is looked
up, so that payload type numbers are translated between IuUP <-> RTP.
Change-Id: Ibc70e0aa00476926dd1f4ea8139c34f31f9cdfa3
diff --git a/include/osmocom/mgcp/iuup_protocol.h b/include/osmocom/mgcp/iuup_protocol.h
new file mode 100644
index 0000000..f4aec1f
--- /dev/null
+++ b/include/osmocom/mgcp/iuup_protocol.h
@@ -0,0 +1,117 @@
+/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
+/* IuUP protocol handling, minimal implementation */
+
+#pragma once
+
+#include <osmocom/core/endian.h>
+#include <osmocom/core/msgb.h>
+
+#define OSMO_IUUP_HEADROOM 32
+
+enum osmo_iuup_pdu_type {
+ OSMO_IUUP_PDU_DATA_WITH_CRC = 0,
+ OSMO_IUUP_PDU_CONTROL_PROCEDURE = 14,
+};
+
+enum osmo_iuup_acknack {
+ OSMO_IUUP_ACKNACK_PROCEDURE = 0,
+ OSMO_IUUP_ACKNACK_ACK = 1,
+ OSMO_IUUP_ACKNACK_NACK = 2,
+};
+
+enum osmo_iuup_procedure {
+ OSMO_IUUP_PROC_INITIALIZATION = 0,
+ OSMO_IUUP_PROC_RATE_CONTROL = 1,
+ OSMO_IUUP_PROC_TIME_ALIGNMENT = 2,
+ OSMO_IUUP_PROC_ERROR_EVENT = 3,
+};
+
+enum osmo_iuup_frame_good {
+ OSMO_IUUP_FRAME_GOOD = 0,
+ OSMO_IUUP_FRAME_BAD = 1,
+ OSMO_IUUP_FRAME_BAD_DUE_TO_RADIO = 2,
+};
+
+struct osmo_iuup_hdr_ctrl {
+#if OSMO_IS_BIG_ENDIAN
+ uint8_t pdu_type:4,
+ ack_nack:2,
+ frame_nr:2;
+ uint8_t mode_version:4,
+ procedure:4;
+ uint8_t header_crc:6,
+ payload_crc_hi:2;
+ uint8_t payload_crc_lo;
+ uint8_t payload[0];
+#elif OSMO_IS_LITTLE_ENDIAN
+ uint8_t frame_nr:2,
+ ack_nack:2,
+ pdu_type:4;
+ uint8_t procedure:4,
+ mode_version:4;
+ uint8_t payload_crc_hi:2,
+ header_crc:6;
+ uint8_t payload_crc_lo;
+ uint8_t payload[0];
+#endif
+} __attribute__((packed));
+
+union osmo_iuup_hdr_ctrl_payload {
+ struct {
+#if OSMO_IS_BIG_ENDIAN
+ uint8_t spare:3,
+ iptis_present:1,
+ subflows:3,
+ chain:1;
+#elif OSMO_IS_LITTLE_ENDIAN
+ uint8_t spare:3,
+ iptis_present:1,
+ subflows:3,
+ chain:1;
+#endif
+ } initialization;
+
+ struct {
+#if OSMO_IS_BIG_ENDIAN
+ uint8_t error_distance:2,
+ error_cause:6;
+#elif OSMO_IS_LITTLE_ENDIAN
+ uint8_t error_cause:6,
+ error_distance:2;
+#endif
+ } error_event;
+};
+
+extern const struct value_string osmo_iuup_error_cause_names[];
+static inline const char *osmo_iuup_error_cause_name(uint8_t val)
+{ return get_value_string(osmo_iuup_error_cause_names, val); }
+
+struct osmo_iuup_hdr_data {
+#if OSMO_IS_BIG_ENDIAN
+ uint8_t pdu_type:4,
+ frame_nr:4;
+ uint8_t frame_good:2,
+ rfci:6;
+ uint8_t header_crc:6,
+ payload_crc_hi:2;
+ uint8_t payload_crc_lo;
+#elif OSMO_IS_LITTLE_ENDIAN
+ uint8_t frame_nr:4,
+ pdu_type:4;
+ uint8_t rfci:6,
+ frame_good:2;
+ uint8_t payload_crc_hi:2,
+ header_crc:6;
+ uint8_t payload_crc_lo;
+#endif
+ uint8_t payload[0];
+} __attribute__((packed));
+
+int osmo_iuup_classify(bool log_errors,
+ const char *log_label,
+ struct msgb *pdu,
+ struct osmo_iuup_hdr_ctrl **is_ctrl,
+ struct osmo_iuup_hdr_data **is_data);
+bool osmo_iuup_is_init(struct msgb *pdu);
+void osmo_iuup_make_init_ack(struct msgb *ack);
+void osmo_iuup_set_checksums(uint8_t *iuup_header_and_payload, unsigned int header_and_payload_len);