1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
#ifndef _OSMOCOM_LAPD_H
#define _OSMOCOM_LAPD_H
#include <stdint.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/prim.h>
/*! \defgroup lapd LAPD implementation common part
* @{
*/
/*! \file lapd_core.h
* primitive related stuff
*/
/*! \brief LAPD related primitives (L2<->L3 SAP)*/
enum osmo_dl_prim {
PRIM_DL_UNIT_DATA, /*!< \brief DL-UNIT-DATA */
PRIM_DL_DATA, /*!< \brief DL-DATA */
PRIM_DL_EST, /*!< \brief DL-ESTABLISH */
PRIM_DL_REL, /*!< \brief DL-RLEEASE */
PRIM_DL_SUSP, /*!< \brief DL-SUSPEND */
PRIM_DL_RES, /*!< \brief DL-RESUME */
PRIM_DL_RECON, /*!< \brief DL-RECONNECT */
PRIM_MDL_ERROR, /*!< \brief MDL-ERROR */
};
/* Uses the same values as RLL, so no conversion for GSM is required. */
#define MDL_CAUSE_T200_EXPIRED 0x01
#define MDL_CAUSE_REEST_REQ 0x02
#define MDL_CAUSE_UNSOL_UA_RESP 0x03
#define MDL_CAUSE_UNSOL_DM_RESP 0x04
#define MDL_CAUSE_UNSOL_DM_RESP_MF 0x05
#define MDL_CAUSE_UNSOL_SPRV_RESP 0x06
#define MDL_CAUSE_SEQ_ERR 0x07
#define MDL_CAUSE_UFRM_INC_PARAM 0x08
#define MDL_CAUSE_SFRM_INC_PARAM 0x09
#define MDL_CAUSE_IFRM_INC_MBITS 0x0a
#define MDL_CAUSE_IFRM_INC_LEN 0x0b
#define MDL_CAUSE_FRM_UNIMPL 0x0c
#define MDL_CAUSE_SABM_MF 0x0d
#define MDL_CAUSE_SABM_INFO_NOTALL 0x0e
#define MDL_CAUSE_FRMR 0x0f
/*! \brief for MDL-ERROR.ind */
struct mdl_error_ind_param {
uint8_t cause; /*!< \brief generic cause value */
};
/*! \brief for DL-REL.req */
struct dl_rel_req_param {
uint8_t mode; /*!< \brief release mode */
};
/*! \brief primitive header for LAPD DL-SAP primitives */
struct osmo_dlsap_prim {
struct osmo_prim_hdr oph; /*!< \brief generic primitive header */
union {
struct mdl_error_ind_param error_ind;
struct dl_rel_req_param rel_req;
} u; /*!< \brief request-specific data */
};
/*! \brief LAPD mode/role */
enum lapd_mode {
LAPD_MODE_USER, /*!< \brief behave like user */
LAPD_MODE_NETWORK, /*!< \brief behave like network */
};
/*! \brief LAPD state (Figure B.2/Q.921)*/
enum lapd_state {
LAPD_STATE_NULL = 0,
LAPD_STATE_TEI_UNASS,
LAPD_STATE_ASS_TEI_WAIT,
LAPD_STATE_EST_TEI_WAIT,
LAPD_STATE_IDLE,
LAPD_STATE_SABM_SENT,
LAPD_STATE_DISC_SENT,
LAPD_STATE_MF_EST,
LAPD_STATE_TIMER_RECOV,
};
/*! \brief LAPD message format (I / S / U) */
enum lapd_format {
LAPD_FORM_UKN = 0,
LAPD_FORM_I,
LAPD_FORM_S,
LAPD_FORM_U,
};
/*! \brief LAPD message context */
struct lapd_msg_ctx {
struct lapd_datalink *dl;
int n201;
/* address */
uint8_t cr;
uint8_t sapi;
uint8_t tei;
uint8_t lpd;
/* control */
uint8_t format;
uint8_t p_f; /* poll / final bit */
uint8_t n_send;
uint8_t n_recv;
uint8_t s_u; /* S or repectivly U function bits */
/* length */
int length;
uint8_t more;
};
struct lapd_cr_ent {
uint8_t cmd;
uint8_t resp;
};
struct lapd_history {
struct msgb *msg; /* message to be sent / NULL, if histoy is empty */
int more; /* if message is fragmented */
};
/*! \brief LAPD datalink */
struct lapd_datalink {
int (*send_dlsap)(struct osmo_dlsap_prim *dp,
struct lapd_msg_ctx *lctx);
int (*send_ph_data_req)(struct lapd_msg_ctx *lctx, struct msgb *msg);
int (*update_pending_frames)(struct lapd_msg_ctx *lctx);
struct {
/*! \brief filled-in once we set the lapd_mode above */
struct lapd_cr_ent loc2rem;
struct lapd_cr_ent rem2loc;
} cr;
enum lapd_mode mode; /*!< \brief current mode of link */
int use_sabme; /*!< \brief use SABME instead of SABM */
int reestablish; /*!< \brief enable reestablish support */
int n200, n200_est_rel; /*!< \brief number of retranmissions */
struct lapd_msg_ctx lctx; /*!< \brief LAPD context */
int maxf; /*!< \brief maximum frame size (after defragmentation) */
uint8_t k; /*!< \brief maximum number of unacknowledged frames */
uint8_t v_range; /*!< \brief range of sequence numbers */
uint8_t v_send; /*!< \brief seq nr of next I frame to be transmitted */
uint8_t v_ack; /*!< \brief last frame ACKed by peer */
uint8_t v_recv; /*!< \brief seq nr of next I frame expected to be received */
uint32_t state; /*!< \brief LAPD state (\ref lapd_state) */
int seq_err_cond; /*!< \brief condition of sequence error */
uint8_t own_busy; /*!< \brief receiver busy on our side */
uint8_t peer_busy; /*!< \brief receiver busy on remote side */
int t200_sec, t200_usec; /*!< \brief retry timer (default 1 sec) */
int t203_sec, t203_usec; /*!< \brief retry timer (default 10 secs) */
struct osmo_timer_list t200; /*!< \brief T200 timer */
struct osmo_timer_list t203; /*!< \brief T203 timer */
uint8_t retrans_ctr; /*!< \brief re-transmission counter */
struct llist_head tx_queue; /*!< \brief frames to L1 */
struct llist_head send_queue; /*!< \brief frames from L3 */
struct msgb *send_buffer; /*!< \brief current frame transmitting */
int send_out; /*!< \brief how much was sent from send_buffer */
struct lapd_history *tx_hist; /*!< \brief tx history structure array */
uint8_t range_hist; /*!< \brief range of history buffer 2..2^n */
struct msgb *rcv_buffer; /*!< \brief buffer to assemble the received message */
struct msgb *cont_res; /*!< \brief buffer to store content resolution data on network side, to detect multiple phones on same channel */
};
void lapd_dl_init(struct lapd_datalink *dl, uint8_t k, uint8_t v_range,
int maxf);
void lapd_dl_exit(struct lapd_datalink *dl);
void lapd_dl_reset(struct lapd_datalink *dl);
int lapd_set_mode(struct lapd_datalink *dl, enum lapd_mode mode);
int lapd_ph_data_ind(struct msgb *msg, struct lapd_msg_ctx *lctx);
int lapd_recv_dlsap(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx);
/*! @} */
#endif /* _OSMOCOM_LAPD_H */
|
