mirror of https://gerrit.osmocom.org/libosmocore
172 lines
5.1 KiB
C
172 lines
5.1 KiB
C
/*! \file lapd_core.h
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* primitive related stuff
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*/
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#pragma once
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#include <stdint.h>
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#include <osmocom/core/timer.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/gsm/prim.h>
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/*! \defgroup lapd LAPD implementation common part
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* @{
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* \file lapd_core.h
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*/
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/*! LAPD related primitives (L2<->L3 SAP)*/
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enum osmo_dl_prim {
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PRIM_DL_UNIT_DATA, /*!< DL-UNIT-DATA */
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PRIM_DL_DATA, /*!< DL-DATA */
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PRIM_DL_EST, /*!< DL-ESTABLISH */
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PRIM_DL_REL, /*!< DL-RLEEASE */
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PRIM_DL_SUSP, /*!< DL-SUSPEND */
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PRIM_DL_RES, /*!< DL-RESUME */
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PRIM_DL_RECON, /*!< DL-RECONNECT */
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PRIM_MDL_ERROR, /*!< MDL-ERROR */
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};
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/* Uses the same values as RLL, so no conversion for GSM is required. */
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#define MDL_CAUSE_T200_EXPIRED 0x01
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#define MDL_CAUSE_REEST_REQ 0x02
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#define MDL_CAUSE_UNSOL_UA_RESP 0x03
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#define MDL_CAUSE_UNSOL_DM_RESP 0x04
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#define MDL_CAUSE_UNSOL_DM_RESP_MF 0x05
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#define MDL_CAUSE_UNSOL_SPRV_RESP 0x06
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#define MDL_CAUSE_SEQ_ERR 0x07
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#define MDL_CAUSE_UFRM_INC_PARAM 0x08
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#define MDL_CAUSE_SFRM_INC_PARAM 0x09
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#define MDL_CAUSE_IFRM_INC_MBITS 0x0a
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#define MDL_CAUSE_IFRM_INC_LEN 0x0b
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#define MDL_CAUSE_FRM_UNIMPL 0x0c
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#define MDL_CAUSE_SABM_MF 0x0d
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#define MDL_CAUSE_SABM_INFO_NOTALL 0x0e
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#define MDL_CAUSE_FRMR 0x0f
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/*! for MDL-ERROR.ind */
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struct mdl_error_ind_param {
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uint8_t cause; /*!< generic cause value */
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};
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/*! for DL-REL.req */
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struct dl_rel_req_param {
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uint8_t mode; /*!< release mode */
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};
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/*! primitive header for LAPD DL-SAP primitives */
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struct osmo_dlsap_prim {
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struct osmo_prim_hdr oph; /*!< generic primitive header */
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union {
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struct mdl_error_ind_param error_ind;
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struct dl_rel_req_param rel_req;
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} u; /*!< request-specific data */
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};
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/*! LAPD mode/role */
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enum lapd_mode {
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LAPD_MODE_USER, /*!< behave like user */
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LAPD_MODE_NETWORK, /*!< behave like network */
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};
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/*! LAPD state (Figure B.2/Q.921)*/
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enum lapd_state {
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LAPD_STATE_NULL = 0,
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LAPD_STATE_TEI_UNASS,
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LAPD_STATE_ASS_TEI_WAIT,
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LAPD_STATE_EST_TEI_WAIT,
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LAPD_STATE_IDLE,
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LAPD_STATE_SABM_SENT,
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LAPD_STATE_DISC_SENT,
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LAPD_STATE_MF_EST,
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LAPD_STATE_TIMER_RECOV,
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};
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/*! LAPD message format (I / S / U) */
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enum lapd_format {
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LAPD_FORM_UKN = 0,
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LAPD_FORM_I,
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LAPD_FORM_S,
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LAPD_FORM_U,
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};
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/*! LAPD message context */
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struct lapd_msg_ctx {
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struct lapd_datalink *dl;
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int n201;
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/* address */
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uint8_t cr;
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uint8_t sapi;
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uint8_t tei;
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uint8_t lpd;
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/* control */
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uint8_t format;
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uint8_t p_f; /* poll / final bit */
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uint8_t n_send;
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uint8_t n_recv;
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uint8_t s_u; /* S or repectivly U function bits */
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/* length */
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int length;
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uint8_t more;
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};
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struct lapd_cr_ent {
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uint8_t cmd;
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uint8_t resp;
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};
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struct lapd_history {
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struct msgb *msg; /* message to be sent / NULL, if histoy is empty */
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int more; /* if message is fragmented */
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};
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/*! LAPD datalink */
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struct lapd_datalink {
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int (*send_dlsap)(struct osmo_dlsap_prim *dp,
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struct lapd_msg_ctx *lctx);
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int (*send_ph_data_req)(struct lapd_msg_ctx *lctx, struct msgb *msg);
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int (*update_pending_frames)(struct lapd_msg_ctx *lctx);
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struct {
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/*! filled-in once we set the lapd_mode above */
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struct lapd_cr_ent loc2rem;
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struct lapd_cr_ent rem2loc;
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} cr;
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enum lapd_mode mode; /*!< current mode of link */
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int use_sabme; /*!< use SABME instead of SABM */
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int reestablish; /*!< enable reestablish support */
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int n200, n200_est_rel; /*!< number of retranmissions */
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struct lapd_msg_ctx lctx; /*!< LAPD context */
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int maxf; /*!< maximum frame size (after defragmentation) */
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uint8_t k; /*!< maximum number of unacknowledged frames */
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uint8_t v_range; /*!< range of sequence numbers */
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uint8_t v_send; /*!< seq nr of next I frame to be transmitted */
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uint8_t v_ack; /*!< last frame ACKed by peer */
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uint8_t v_recv; /*!< seq nr of next I frame expected to be received */
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uint32_t state; /*!< LAPD state (\ref lapd_state) */
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int seq_err_cond; /*!< condition of sequence error */
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uint8_t own_busy; /*!< receiver busy on our side */
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uint8_t peer_busy; /*!< receiver busy on remote side */
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int t200_sec, t200_usec; /*!< retry timer (default 1 sec) */
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int t203_sec, t203_usec; /*!< retry timer (default 10 secs) */
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struct osmo_timer_list t200; /*!< T200 timer */
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struct osmo_timer_list t203; /*!< T203 timer */
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uint8_t retrans_ctr; /*!< re-transmission counter */
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struct llist_head tx_queue; /*!< frames to L1 */
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struct llist_head send_queue; /*!< frames from L3 */
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struct msgb *send_buffer; /*!< current frame transmitting */
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int send_out; /*!< how much was sent from send_buffer */
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struct lapd_history *tx_hist; /*!< tx history structure array */
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uint8_t range_hist; /*!< range of history buffer 2..2^n */
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struct msgb *rcv_buffer; /*!< buffer to assemble the received message */
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struct msgb *cont_res; /*!< buffer to store content resolution data on network side, to detect multiple phones on same channel */
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};
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void lapd_dl_init(struct lapd_datalink *dl, uint8_t k, uint8_t v_range,
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int maxf);
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void lapd_dl_exit(struct lapd_datalink *dl);
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void lapd_dl_reset(struct lapd_datalink *dl);
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int lapd_set_mode(struct lapd_datalink *dl, enum lapd_mode mode);
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int lapd_ph_data_ind(struct msgb *msg, struct lapd_msg_ctx *lctx);
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int lapd_recv_dlsap(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx);
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/*! @} */
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