mirror of https://gerrit.osmocom.org/libosmocore
1507 lines
41 KiB
C
1507 lines
41 KiB
C
/*! \file lapdm.c
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* GSM LAPDm (TS 04.06) implementation. */
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/*
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* (C) 2010-2019 by Harald Welte <laforge@gnumonks.org>
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* (C) 2010-2011 by Andreas Eversberg <jolly@eversberg.eu>
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* (C) 2014-2016 by sysmocom - s.f.m.c GmbH
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*
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* All Rights Reserved
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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/*! \addtogroup lapdm
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* @{
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* \file lapdm.c */
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <errno.h>
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#include <osmocom/core/logging.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/core/utils.h>
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#include <osmocom/gsm/tlv.h>
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#include <osmocom/gsm/rsl.h>
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#include <osmocom/gsm/prim.h>
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/gsm/lapdm.h>
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#include <osmocom/gsm/protocol/gsm_04_08.h>
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#include <osmocom/gsm/protocol/gsm_08_58.h>
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#define LAPD_U_SABM 0x7
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/* TS 04.06 Figure 4 / Section 3.2 */
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#define LAPDm_LPD_NORMAL 0
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#define LAPDm_LPD_SMSCB 1
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#define LAPDm_SAPI_NORMAL 0
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#define LAPDm_SAPI_SMS 3
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#define LAPDm_ADDR(lpd, sapi, cr) ((((lpd) & 0x3) << 5) | (((sapi) & 0x7) << 2) | (((cr) & 0x1) << 1) | 0x1)
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#define LAPDm_ADDR_LPD(addr) (((addr) >> 5) & 0x3)
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#define LAPDm_ADDR_SAPI(addr) (((addr) >> 2) & 0x7)
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#define LAPDm_ADDR_CR(addr) (((addr) >> 1) & 0x1)
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#define LAPDm_ADDR_EA(addr) ((addr) & 0x1)
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/* TS 04.06 Table 3 / Section 3.4.3 */
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#define LAPDm_CTRL_I(nr, ns, p) ((((nr) & 0x7) << 5) | (((p) & 0x1) << 4) | (((ns) & 0x7) << 1))
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#define LAPDm_CTRL_S(nr, s, p) ((((nr) & 0x7) << 5) | (((p) & 0x1) << 4) | (((s) & 0x3) << 2) | 0x1)
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#define LAPDm_CTRL_U(u, p) ((((u) & 0x1c) << (5-2)) | (((p) & 0x1) << 4) | (((u) & 0x3) << 2) | 0x3)
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#define LAPDm_CTRL_is_I(ctrl) (((ctrl) & 0x1) == 0)
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#define LAPDm_CTRL_is_S(ctrl) (((ctrl) & 0x3) == 1)
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#define LAPDm_CTRL_is_U(ctrl) (((ctrl) & 0x3) == 3)
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#define LAPDm_CTRL_U_BITS(ctrl) ((((ctrl) & 0xC) >> 2) | ((ctrl) & 0xE0) >> 3)
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#define LAPDm_CTRL_PF_BIT(ctrl) (((ctrl) >> 4) & 0x1)
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#define LAPDm_CTRL_S_BITS(ctrl) (((ctrl) & 0xC) >> 2)
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#define LAPDm_CTRL_I_Ns(ctrl) (((ctrl) & 0xE) >> 1)
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#define LAPDm_CTRL_Nr(ctrl) (((ctrl) & 0xE0) >> 5)
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#define LAPDm_LEN(len) ((len << 2) | 0x1)
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#define LAPDm_MORE 0x2
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#define LAPDm_EL 0x1
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#define LAPDm_U_UI 0x0
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/* TS 04.06 Section 5.8.3 */
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#define N201_AB_SACCH 18
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#define N201_AB_SDCCH 20
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#define N201_AB_FACCH 20
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#define N201_Bbis 23
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#define N201_Bter_SACCH 21
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#define N201_Bter_SDCCH 23
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#define N201_Bter_FACCH 23
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#define N201_B4 19
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/* 5.8.2.1 N200 during establish and release */
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#define N200_EST_REL 5
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/* 5.8.2.1 N200 during timer recovery state */
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#define N200_TR_SACCH 5
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#define N200_TR_SDCCH 23
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#define N200_TR_FACCH_FR 34
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#define N200_TR_EFACCH_FR 48
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#define N200_TR_FACCH_HR 29
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/* FIXME: set N200 depending on chan_nr */
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#define N200 N200_TR_SDCCH
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enum lapdm_format {
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LAPDm_FMT_A,
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LAPDm_FMT_B,
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LAPDm_FMT_Bbis,
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LAPDm_FMT_Bter,
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LAPDm_FMT_B4,
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};
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const struct value_string osmo_ph_prim_names[] = {
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{ PRIM_PH_DATA, "PH-DATA" },
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{ PRIM_PH_RACH, "PH-RANDOM_ACCESS" },
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{ PRIM_PH_CONN, "PH-CONNECT" },
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{ PRIM_PH_EMPTY_FRAME, "PH-EMPTY_FRAME" },
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{ PRIM_PH_RTS, "PH-RTS" },
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{ PRIM_MPH_INFO, "MPH-INFO" },
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{ PRIM_TCH, "TCH" },
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{ PRIM_TCH_RTS, "TCH-RTS" },
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{ 0, NULL }
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};
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extern void *tall_lapd_ctx;
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static int lapdm_send_ph_data_req(struct lapd_msg_ctx *lctx, struct msgb *msg);
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static int send_rslms_dlsap(struct osmo_dlsap_prim *dp,
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struct lapd_msg_ctx *lctx);
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static int update_pending_frames(struct lapd_msg_ctx *lctx);
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static void lapdm_dl_init(struct lapdm_datalink *dl,
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struct lapdm_entity *entity, int t200_ms, uint32_t n200,
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const char *name)
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{
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memset(dl, 0, sizeof(*dl));
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dl->entity = entity;
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lapd_dl_init2(&dl->dl, 1, 8, 251, name); /* Section 5.8.5 of TS 04.06 */
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dl->dl.reestablish = 0; /* GSM uses no reestablish */
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dl->dl.send_ph_data_req = lapdm_send_ph_data_req;
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dl->dl.send_dlsap = send_rslms_dlsap;
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dl->dl.update_pending_frames = update_pending_frames;
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dl->dl.n200_est_rel = N200_EST_REL;
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dl->dl.n200 = n200;
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dl->dl.t203_sec = 0; dl->dl.t203_usec = 0;
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dl->dl.t200_sec = t200_ms / 1000; dl->dl.t200_usec = (t200_ms % 1000) * 1000;
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}
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/*! initialize a LAPDm entity and all datalinks inside
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* \param[in] le LAPDm entity
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* \param[in] mode \ref lapdm_mode (BTS/MS)
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* \param[in] t200 T200 re-transmission timer for all SAPIs in seconds
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*
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* Don't use this function; It doesn't support different T200 values per API
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* and doesn't permit the caller to specify the N200 counter, both of which
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* are required by GSM specs and supported by lapdm_entity_init2().
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*/
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void lapdm_entity_init(struct lapdm_entity *le, enum lapdm_mode mode, int t200)
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{
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/* convert from single full-second value to per-SAPI milli-second value */
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int t200_ms_sapi_arr[_NR_DL_SAPI];
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int i;
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for (i = 0; i < ARRAY_SIZE(t200_ms_sapi_arr); i++)
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t200_ms_sapi_arr[i] = t200 * 1000;
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return lapdm_entity_init3(le, mode, t200_ms_sapi_arr, N200, NULL);
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}
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/*! initialize a LAPDm entity and all datalinks inside
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* \param[in] le LAPDm entity
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* \param[in] mode lapdm_mode (BTS/MS)
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* \param[in] t200_ms per-SAPI array of T200 re-transmission timer in milli-seconds
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* \param[in] n200 N200 re-transmisison count
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*/
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void lapdm_entity_init2(struct lapdm_entity *le, enum lapdm_mode mode,
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const int *t200_ms, int n200)
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{
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lapdm_entity_init3(le, mode, t200_ms, n200, NULL);
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}
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/*! initialize a LAPDm entity and all datalinks inside
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* \param[in] le LAPDm entity
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* \param[in] mode lapdm_mode (BTS/MS)
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* \param[in] t200_ms per-SAPI array of T200 re-transmission timer in milli-seconds
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* \param[in] n200 N200 re-transmisison count
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* \param[in] name human-readable name (will be copied internally + extended with SAPI)
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*/
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void lapdm_entity_init3(struct lapdm_entity *le, enum lapdm_mode mode,
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const int *t200_ms, int n200, const char *name_pfx)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(le->datalink); i++) {
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char name[256];
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if (name_pfx) {
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snprintf(name, sizeof(name), "%s[%s]", name_pfx, i == 0 ? "0" : "3");
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lapdm_dl_init(&le->datalink[i], le, t200_ms[i], n200, name);
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} else
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lapdm_dl_init(&le->datalink[i], le, t200_ms[i], n200, NULL);
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}
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lapdm_entity_set_mode(le, mode);
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}
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static int get_n200_dcch(enum gsm_chan_t chan_t)
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{
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switch (chan_t) {
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case GSM_LCHAN_SDCCH:
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return N200_TR_SDCCH;
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case GSM_LCHAN_TCH_F:
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return N200_TR_FACCH_FR;
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case GSM_LCHAN_TCH_H:
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return N200_TR_FACCH_HR;
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default:
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return -1;
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}
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}
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/*! initialize a LAPDm channel and all its channels
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* \param[in] lc lapdm_channel to be initialized
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* \param[in] mode lapdm_mode (BTS/MS)
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*
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* Don't use this function; It doesn't support different T200 values per API
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* and doesn't set the correct N200 counter, both of which
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* are required by GSM specs and supported by lapdm_channel_init2().
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*/
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void lapdm_channel_init(struct lapdm_channel *lc, enum lapdm_mode mode)
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{
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/* emulate old backwards-compatible behavior with 1s/2s */
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const int t200_ms_dcch[_NR_DL_SAPI] = { 1000, 1000 };
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const int t200_ms_acch[_NR_DL_SAPI] = { 2000, 2000 };
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lapdm_channel_init3(lc, mode, t200_ms_dcch, t200_ms_acch, GSM_LCHAN_SDCCH, NULL);
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}
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/*! initialize a LAPDm channel and all its channels
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* \param[in] lc \ref lapdm_channel to be initialized
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* \param[in] mode \ref lapdm_mode (BTS/MS)
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* \param[in] t200_ms_dcch per-SAPI array of T200 in milli-seconds for DCCH
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* \param[in] t200_ms_acch per-SAPI array of T200 in milli-seconds for SACCH
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* \param[in] chan_t GSM channel type (to correctly set N200)
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*/
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int lapdm_channel_init2(struct lapdm_channel *lc, enum lapdm_mode mode,
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const int *t200_ms_dcch, const int *t200_ms_acch, enum gsm_chan_t chan_t)
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{
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return lapdm_channel_init3(lc, mode, t200_ms_dcch, t200_ms_acch, chan_t, NULL);
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}
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/*! initialize a LAPDm channel and all its channels
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* \param[in] lc \ref lapdm_channel to be initialized
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* \param[in] mode \ref lapdm_mode (BTS/MS)
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* \param[in] t200_ms_dcch per-SAPI array of T200 in milli-seconds for DCCH
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* \param[in] t200_ms_acch per-SAPI array of T200 in milli-seconds for SACCH
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* \param[in] chan_t GSM channel type (to correctly set N200)
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* \param[in] name_pfx human-readable name (copied by function + extended with ACCH/DCCH)
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*/
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int lapdm_channel_init3(struct lapdm_channel *lc, enum lapdm_mode mode,
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const int *t200_ms_dcch, const int *t200_ms_acch, enum gsm_chan_t chan_t,
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const char *name_pfx)
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{
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int n200_dcch = get_n200_dcch(chan_t);
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char namebuf[256];
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char *name = NULL;
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if (n200_dcch < 0)
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return -EINVAL;
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osmo_talloc_replace_string(tall_lapd_ctx, &lc->name, name_pfx);
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if (name_pfx) {
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snprintf(namebuf, sizeof(namebuf), "%s[ACCH]", name_pfx);
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name = namebuf;
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}
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lapdm_entity_init3(&lc->lapdm_acch, mode, t200_ms_acch, N200_TR_SACCH, name);
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lc->lapdm_acch.lapdm_ch = lc;
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if (name_pfx) {
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snprintf(namebuf, sizeof(namebuf), "%s[DCCH]", name_pfx);
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name = namebuf;
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}
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lapdm_entity_init3(&lc->lapdm_dcch, mode, t200_ms_dcch, n200_dcch, name);
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lc->lapdm_dcch.lapdm_ch = lc;
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return 0;
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}
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/*! flush and release all resoures in LAPDm entity */
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void lapdm_entity_exit(struct lapdm_entity *le)
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{
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unsigned int i;
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struct lapdm_datalink *dl;
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for (i = 0; i < ARRAY_SIZE(le->datalink); i++) {
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dl = &le->datalink[i];
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lapd_dl_exit(&dl->dl);
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}
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}
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/* lfush and release all resources in LAPDm channel
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*
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* A convenience wrapper calling \ref lapdm_entity_exit on both
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* entities inside the \ref lapdm_channel
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*/
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void lapdm_channel_exit(struct lapdm_channel *lc)
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{
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lapdm_entity_exit(&lc->lapdm_acch);
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lapdm_entity_exit(&lc->lapdm_dcch);
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}
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struct lapdm_datalink *lapdm_datalink_for_sapi(struct lapdm_entity *le, uint8_t sapi)
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{
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switch (sapi) {
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case LAPDm_SAPI_NORMAL:
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return &le->datalink[0];
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case LAPDm_SAPI_SMS:
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return &le->datalink[1];
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default:
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return NULL;
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}
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}
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/* Append padding (if required) */
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static void lapdm_pad_msgb(struct msgb *msg, uint8_t n201)
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{
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int pad_len = n201 - msgb_l2len(msg);
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uint8_t *data;
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if (pad_len < 0) {
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LOGP(DLLAPD, LOGL_ERROR,
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"cannot pad message that is already too big!\n");
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return;
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}
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data = msgb_put(msg, pad_len); /* TODO: random padding */
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memset(data, GSM_MACBLOCK_PADDING, pad_len);
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}
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/* input function that L2 calls when sending messages up to L3 */
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static int rslms_sendmsg(struct msgb *msg, struct lapdm_entity *le)
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{
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if (!le->l3_cb) {
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msgb_free(msg);
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return -EIO;
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}
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/* call the layer2 message handler that is registered */
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return le->l3_cb(msg, le, le->l3_ctx);
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}
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/* write a frame into the tx queue */
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static int tx_ph_data_enqueue(struct lapdm_datalink *dl, struct msgb *msg,
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uint8_t chan_nr, uint8_t link_id, uint8_t pad)
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{
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struct lapdm_entity *le = dl->entity;
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struct osmo_phsap_prim pp;
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/* if there is a pending message, queue it */
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if (le->tx_pending || le->flags & LAPDM_ENT_F_POLLING_ONLY) {
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*msgb_push(msg, 1) = pad;
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*msgb_push(msg, 1) = link_id;
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*msgb_push(msg, 1) = chan_nr;
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msgb_enqueue(&dl->dl.tx_queue, msg);
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return -EBUSY;
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}
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osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_DATA,
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PRIM_OP_REQUEST, msg);
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pp.u.data.chan_nr = chan_nr;
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pp.u.data.link_id = link_id;
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/* send the frame now */
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le->tx_pending = 0; /* disabled flow control */
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lapdm_pad_msgb(msg, pad);
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return le->l1_prim_cb(&pp.oph, le->l1_ctx);
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}
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/* Dequeue a Downlink message for DCCH (dedicated channel) */
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static struct msgb *tx_dequeue_dcch_msgb(struct lapdm_entity *le)
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{
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struct msgb *msg;
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/* SAPI=0 always has higher priority than SAPI=3 */
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msg = msgb_dequeue(&le->datalink[DL_SAPI0].dl.tx_queue);
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if (msg == NULL) /* no SAPI=0 messages, dequeue SAPI=3 (if any) */
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msg = msgb_dequeue(&le->datalink[DL_SAPI3].dl.tx_queue);
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return msg;
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}
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/* Dequeue a Downlink message for ACCH (associated channel) */
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static struct msgb *tx_dequeue_acch_msgb(struct lapdm_entity *le)
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{
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struct lapdm_datalink *dl;
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int last = le->last_tx_dequeue;
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int i = last, n = ARRAY_SIZE(le->datalink);
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struct msgb *msg = NULL;
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/* round-robin dequeue */
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do {
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/* next */
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i = (i + 1) % n;
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dl = &le->datalink[i];
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if ((msg = msgb_dequeue(&dl->dl.tx_queue)))
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break;
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} while (i != last);
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if (msg) {
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/* Set last dequeue position */
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le->last_tx_dequeue = i;
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}
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return msg;
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}
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/*! dequeue a msg that's pending transmission via L1 and wrap it into
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* a osmo_phsap_prim */
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int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp)
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{
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struct msgb *msg;
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uint8_t pad;
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/* Dequeue depending on channel type: DCCH or ACCH.
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* See 3GPP TS 44.005, section 4.2.2 "Priority". */
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if (le == &le->lapdm_ch->lapdm_dcch)
|
|
msg = tx_dequeue_dcch_msgb(le);
|
|
else
|
|
msg = tx_dequeue_acch_msgb(le);
|
|
if (!msg)
|
|
return -ENODEV;
|
|
|
|
/* if we have a message, send PH-DATA.req */
|
|
osmo_prim_init(&pp->oph, SAP_GSM_PH, PRIM_PH_DATA,
|
|
PRIM_OP_REQUEST, msg);
|
|
|
|
/* Pull chan_nr and link_id */
|
|
pp->u.data.chan_nr = *msg->data;
|
|
msgb_pull(msg, 1);
|
|
pp->u.data.link_id = *msg->data;
|
|
msgb_pull(msg, 1);
|
|
pad = *msg->data;
|
|
msgb_pull(msg, 1);
|
|
|
|
/* Pad the frame, we can transmit now */
|
|
lapdm_pad_msgb(msg, pad);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* get next frame from the tx queue. because the ms has multiple datalinks,
|
|
* each datalink's queue is read round-robin.
|
|
*/
|
|
static int l2_ph_data_conf(struct msgb *msg, struct lapdm_entity *le)
|
|
{
|
|
struct osmo_phsap_prim pp;
|
|
|
|
/* we may send again */
|
|
le->tx_pending = 0;
|
|
|
|
/* free confirm message */
|
|
if (msg)
|
|
msgb_free(msg);
|
|
|
|
if (lapdm_phsap_dequeue_prim(le, &pp) < 0) {
|
|
/* no message in all queues */
|
|
|
|
/* If user didn't request PH-EMPTY_FRAME.req, abort */
|
|
if (!(le->flags & LAPDM_ENT_F_EMPTY_FRAME))
|
|
return 0;
|
|
|
|
/* otherwise, send PH-EMPTY_FRAME.req */
|
|
osmo_prim_init(&pp.oph, SAP_GSM_PH,
|
|
PRIM_PH_EMPTY_FRAME,
|
|
PRIM_OP_REQUEST, NULL);
|
|
} else {
|
|
le->tx_pending = 1;
|
|
}
|
|
|
|
return le->l1_prim_cb(&pp.oph, le->l1_ctx);
|
|
}
|
|
|
|
/* Is a given msg_type "transparent" as per TS 48.058 Section 8.1 */
|
|
static int rsl_is_transparent(uint8_t msg_type)
|
|
{
|
|
switch (msg_type) {
|
|
case RSL_MT_DATA_IND:
|
|
case RSL_MT_UNIT_DATA_IND:
|
|
return 1;
|
|
case RSL_MT_DATA_REQ:
|
|
case RSL_MT_UNIT_DATA_REQ:
|
|
return 1;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* Create RSLms various RSLms messages */
|
|
static int send_rslms_rll_l3(uint8_t msg_type, struct lapdm_msg_ctx *mctx,
|
|
struct msgb *msg)
|
|
{
|
|
int transparent = rsl_is_transparent(msg_type);
|
|
|
|
/* Add the RSL + RLL header */
|
|
rsl_rll_push_l3(msg, msg_type, mctx->chan_nr, mctx->link_id, transparent);
|
|
|
|
/* send off the RSLms message to L3 */
|
|
return rslms_sendmsg(msg, mctx->dl->entity);
|
|
}
|
|
|
|
/* Take a B4 format message from L1 and create RSLms UNIT DATA IND */
|
|
static int send_rslms_rll_l3_ui(struct lapdm_msg_ctx *mctx, struct msgb *msg)
|
|
{
|
|
uint8_t l3_len = msg->tail - (uint8_t *)msgb_l3(msg);
|
|
|
|
/* Add the RSL + RLL header */
|
|
msgb_tv16_push(msg, RSL_IE_L3_INFO, l3_len);
|
|
|
|
/* Add two non-standard IEs carrying MS power and TA values for B4 (SACCH) */
|
|
if (mctx->lapdm_fmt == LAPDm_FMT_B4) {
|
|
msgb_tv_push(msg, RSL_IE_MS_POWER, mctx->tx_power_ind);
|
|
msgb_tv_push(msg, RSL_IE_TIMING_ADVANCE, mctx->ta_ind);
|
|
}
|
|
|
|
rsl_rll_push_hdr(msg, RSL_MT_UNIT_DATA_IND, mctx->chan_nr,
|
|
mctx->link_id, 1);
|
|
|
|
return rslms_sendmsg(msg, mctx->dl->entity);
|
|
}
|
|
|
|
static int send_rll_simple(uint8_t msg_type, struct lapdm_msg_ctx *mctx)
|
|
{
|
|
struct msgb *msg;
|
|
int transparent = rsl_is_transparent(msg_type);
|
|
|
|
msg = rsl_rll_simple(msg_type, mctx->chan_nr, mctx->link_id, transparent);
|
|
|
|
/* send off the RSLms message to L3 */
|
|
return rslms_sendmsg(msg, mctx->dl->entity);
|
|
}
|
|
|
|
static int rsl_rll_error(uint8_t cause, struct lapdm_msg_ctx *mctx)
|
|
{
|
|
struct msgb *msg;
|
|
|
|
LOGDL(&mctx->dl->dl, LOGL_NOTICE, "sending MDL-ERROR-IND %d\n", cause);
|
|
msg = rsl_rll_simple(RSL_MT_ERROR_IND, mctx->chan_nr, mctx->link_id, 0);
|
|
msgb_tlv_put(msg, RSL_IE_RLM_CAUSE, 1, &cause);
|
|
return rslms_sendmsg(msg, mctx->dl->entity);
|
|
}
|
|
|
|
/* DLSAP L2 -> L3 (RSLms) */
|
|
static int send_rslms_dlsap(struct osmo_dlsap_prim *dp,
|
|
struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct lapdm_datalink *mdl =
|
|
container_of(dl, struct lapdm_datalink, dl);
|
|
struct lapdm_msg_ctx *mctx = &mdl->mctx;
|
|
uint8_t rll_msg = 0;
|
|
|
|
switch (OSMO_PRIM_HDR(&dp->oph)) {
|
|
case OSMO_PRIM(PRIM_DL_EST, PRIM_OP_INDICATION):
|
|
rll_msg = RSL_MT_EST_IND;
|
|
break;
|
|
case OSMO_PRIM(PRIM_DL_EST, PRIM_OP_CONFIRM):
|
|
rll_msg = RSL_MT_EST_CONF;
|
|
break;
|
|
case OSMO_PRIM(PRIM_DL_DATA, PRIM_OP_INDICATION):
|
|
rll_msg = RSL_MT_DATA_IND;
|
|
break;
|
|
case OSMO_PRIM(PRIM_DL_UNIT_DATA, PRIM_OP_INDICATION):
|
|
return send_rslms_rll_l3_ui(mctx, dp->oph.msg);
|
|
case OSMO_PRIM(PRIM_DL_REL, PRIM_OP_INDICATION):
|
|
rll_msg = RSL_MT_REL_IND;
|
|
break;
|
|
case OSMO_PRIM(PRIM_DL_REL, PRIM_OP_CONFIRM):
|
|
rll_msg = RSL_MT_REL_CONF;
|
|
break;
|
|
case OSMO_PRIM(PRIM_DL_SUSP, PRIM_OP_CONFIRM):
|
|
rll_msg = RSL_MT_SUSP_CONF;
|
|
break;
|
|
case OSMO_PRIM(PRIM_MDL_ERROR, PRIM_OP_INDICATION):
|
|
rsl_rll_error(dp->u.error_ind.cause, mctx);
|
|
if (dp->oph.msg)
|
|
msgb_free(dp->oph.msg);
|
|
return 0;
|
|
}
|
|
|
|
if (!rll_msg) {
|
|
LOGDL(dl, LOGL_ERROR, "Unsupported op %d, prim %d. Please "
|
|
"fix!\n", dp->oph.primitive, dp->oph.operation);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!dp->oph.msg)
|
|
return send_rll_simple(rll_msg, mctx);
|
|
|
|
return send_rslms_rll_l3(rll_msg, mctx, dp->oph.msg);
|
|
}
|
|
|
|
/* send a data frame to layer 1 */
|
|
static int lapdm_send_ph_data_req(struct lapd_msg_ctx *lctx, struct msgb *msg)
|
|
{
|
|
uint8_t l3_len = msg->tail - msg->data;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct lapdm_datalink *mdl =
|
|
container_of(dl, struct lapdm_datalink, dl);
|
|
struct lapdm_msg_ctx *mctx = &mdl->mctx;
|
|
int format = lctx->format;
|
|
|
|
/* prepend l2 header */
|
|
msg->l2h = msgb_push(msg, 3);
|
|
msg->l2h[0] = LAPDm_ADDR(lctx->lpd, lctx->sapi, lctx->cr);
|
|
/* EA is set here too */
|
|
switch (format) {
|
|
case LAPD_FORM_I:
|
|
msg->l2h[1] = LAPDm_CTRL_I(lctx->n_recv, lctx->n_send,
|
|
lctx->p_f);
|
|
break;
|
|
case LAPD_FORM_S:
|
|
msg->l2h[1] = LAPDm_CTRL_S(lctx->n_recv, lctx->s_u, lctx->p_f);
|
|
break;
|
|
case LAPD_FORM_U:
|
|
msg->l2h[1] = LAPDm_CTRL_U(lctx->s_u, lctx->p_f);
|
|
break;
|
|
default:
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
msg->l2h[2] = LAPDm_LEN(l3_len); /* EL is set here too */
|
|
if (lctx->more)
|
|
msg->l2h[2] |= LAPDm_MORE;
|
|
|
|
/* add ACCH header with last indicated tx-power and TA */
|
|
if ((mctx->link_id & 0x40)) {
|
|
struct lapdm_entity *le = mdl->entity;
|
|
|
|
msg->l2h = msgb_push(msg, 2);
|
|
msg->l2h[0] = le->tx_power;
|
|
msg->l2h[1] = le->ta;
|
|
}
|
|
|
|
return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id,
|
|
23);
|
|
}
|
|
|
|
static int update_pending_frames(struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg;
|
|
int rc = -1;
|
|
|
|
llist_for_each_entry(msg, &dl->tx_queue, list) {
|
|
if (LAPDm_CTRL_is_I(msg->l2h[1])) {
|
|
msg->l2h[1] = LAPDm_CTRL_I(dl->v_recv, LAPDm_CTRL_I_Ns(msg->l2h[1]),
|
|
LAPDm_CTRL_PF_BIT(msg->l2h[1]));
|
|
rc = 0;
|
|
} else if (LAPDm_CTRL_is_S(msg->l2h[1])) {
|
|
LOGDL(dl, LOGL_ERROR, "Supervisory frame in queue, this shouldn't happen\n");
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/* determine if receiving a given LAPDm message is not permitted */
|
|
static int lapdm_rx_not_permitted(const struct lapdm_entity *le,
|
|
const struct lapd_msg_ctx *lctx)
|
|
{
|
|
/* we currently only implement SABM related checks here */
|
|
if (lctx->format != LAPD_FORM_U || lctx->s_u != LAPD_U_SABM)
|
|
return 0;
|
|
|
|
if (le->mode == LAPDM_MODE_BTS) {
|
|
if (le == &le->lapdm_ch->lapdm_acch) {
|
|
/* no contention resolution on SACCH */
|
|
if (lctx->length > 0)
|
|
return RLL_CAUSE_SABM_INFO_NOTALL;
|
|
} else {
|
|
switch (lctx->sapi) {
|
|
case 3:
|
|
/* SAPI3 doesn't support contention resolution */
|
|
if (lctx->length > 0)
|
|
return RLL_CAUSE_SABM_INFO_NOTALL;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
} else if (le->mode == LAPDM_MODE_MS) {
|
|
/* contention resolution (L3 present) is only sent by MS, but
|
|
* never received by it */
|
|
if (lctx->length > 0)
|
|
return RLL_CAUSE_SABM_INFO_NOTALL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* input into layer2 (from layer 1) */
|
|
static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le,
|
|
uint8_t chan_nr, uint8_t link_id)
|
|
{
|
|
uint8_t cbits = chan_nr >> 3;
|
|
uint8_t sapi; /* we cannot take SAPI from link_id, as L1 has no clue */
|
|
struct lapdm_msg_ctx mctx;
|
|
struct lapd_msg_ctx lctx;
|
|
int rc = 0;
|
|
int n201;
|
|
|
|
/* when we reach here, we have a msgb with l2h pointing to the raw
|
|
* 23byte mac block. The l1h has already been purged. */
|
|
|
|
memset(&mctx, 0, sizeof(mctx));
|
|
mctx.chan_nr = chan_nr;
|
|
mctx.link_id = link_id;
|
|
|
|
/* check for L1 chan_nr/link_id and determine LAPDm hdr format */
|
|
if (cbits == 0x10 || cbits == 0x12) {
|
|
/* Format Bbis is used on BCCH and CCCH(PCH, NCH and AGCH) */
|
|
mctx.lapdm_fmt = LAPDm_FMT_Bbis;
|
|
n201 = N201_Bbis;
|
|
sapi = 0;
|
|
} else {
|
|
if (mctx.link_id & 0x40) {
|
|
/* It was received from network on SACCH */
|
|
|
|
/* If UI on SACCH sent by BTS, lapdm_fmt must be B4 */
|
|
if (le->mode == LAPDM_MODE_MS
|
|
&& LAPDm_CTRL_is_U(msg->l2h[3])
|
|
&& LAPDm_CTRL_U_BITS(msg->l2h[3]) == 0) {
|
|
mctx.lapdm_fmt = LAPDm_FMT_B4;
|
|
n201 = N201_B4;
|
|
} else {
|
|
mctx.lapdm_fmt = LAPDm_FMT_B;
|
|
n201 = N201_AB_SACCH;
|
|
}
|
|
/* SACCH frames have a two-byte L1 header that
|
|
* OsmocomBB L1 doesn't strip */
|
|
mctx.tx_power_ind = msg->l2h[0] & 0x1f;
|
|
mctx.ta_ind = msg->l2h[1];
|
|
msgb_pull(msg, 2);
|
|
msg->l2h += 2;
|
|
sapi = (msg->l2h[0] >> 2) & 7;
|
|
} else {
|
|
mctx.lapdm_fmt = LAPDm_FMT_B;
|
|
n201 = N201_AB_SDCCH;
|
|
sapi = (msg->l2h[0] >> 2) & 7;
|
|
}
|
|
}
|
|
|
|
mctx.dl = lapdm_datalink_for_sapi(le, sapi);
|
|
/* G.2.1 No action on frames containing an unallocated SAPI. */
|
|
if (!mctx.dl) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Received frame for unsupported SAPI %d!\n", sapi);
|
|
msgb_free(msg);
|
|
return -EIO;
|
|
}
|
|
|
|
switch (mctx.lapdm_fmt) {
|
|
case LAPDm_FMT_A:
|
|
case LAPDm_FMT_B:
|
|
case LAPDm_FMT_B4:
|
|
lctx.dl = &mctx.dl->dl;
|
|
/* obtain SAPI from address field */
|
|
mctx.link_id |= LAPDm_ADDR_SAPI(msg->l2h[0]);
|
|
/* G.2.3 EA bit set to "0" is not allowed in GSM */
|
|
if (!LAPDm_ADDR_EA(msg->l2h[0])) {
|
|
LOGDL(lctx.dl, LOGL_NOTICE, "EA bit 0 is not allowed in GSM\n");
|
|
msgb_free(msg);
|
|
rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, &mctx);
|
|
return -EINVAL;
|
|
}
|
|
/* adress field */
|
|
lctx.lpd = LAPDm_ADDR_LPD(msg->l2h[0]);
|
|
lctx.sapi = LAPDm_ADDR_SAPI(msg->l2h[0]);
|
|
lctx.cr = LAPDm_ADDR_CR(msg->l2h[0]);
|
|
/* command field */
|
|
if (LAPDm_CTRL_is_I(msg->l2h[1])) {
|
|
lctx.format = LAPD_FORM_I;
|
|
lctx.n_send = LAPDm_CTRL_I_Ns(msg->l2h[1]);
|
|
lctx.n_recv = LAPDm_CTRL_Nr(msg->l2h[1]);
|
|
} else if (LAPDm_CTRL_is_S(msg->l2h[1])) {
|
|
lctx.format = LAPD_FORM_S;
|
|
lctx.n_recv = LAPDm_CTRL_Nr(msg->l2h[1]);
|
|
lctx.s_u = LAPDm_CTRL_S_BITS(msg->l2h[1]);
|
|
} else if (LAPDm_CTRL_is_U(msg->l2h[1])) {
|
|
lctx.format = LAPD_FORM_U;
|
|
lctx.s_u = LAPDm_CTRL_U_BITS(msg->l2h[1]);
|
|
} else
|
|
lctx.format = LAPD_FORM_UKN;
|
|
lctx.p_f = LAPDm_CTRL_PF_BIT(msg->l2h[1]);
|
|
if (lctx.sapi != LAPDm_SAPI_NORMAL
|
|
&& lctx.sapi != LAPDm_SAPI_SMS
|
|
&& lctx.format == LAPD_FORM_U
|
|
&& lctx.s_u == LAPDm_U_UI) {
|
|
/* 5.3.3 UI frames with invalid SAPI values shall be
|
|
* discarded
|
|
*/
|
|
LOGDL(lctx.dl, LOGL_INFO, "sapi=%u (discarding)\n", lctx.sapi);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
if (mctx.lapdm_fmt == LAPDm_FMT_B4) {
|
|
lctx.n201 = n201;
|
|
lctx.length = n201;
|
|
lctx.more = 0;
|
|
msg->l3h = msg->l2h + 2;
|
|
msgb_pull_to_l3(msg);
|
|
} else {
|
|
/* length field */
|
|
if (!(msg->l2h[2] & LAPDm_EL)) {
|
|
/* G.4.1 If the EL bit is set to "0", an
|
|
* MDL-ERROR-INDICATION primitive with cause
|
|
* "frame not implemented" is sent to the
|
|
* mobile management entity. */
|
|
LOGDL(lctx.dl, LOGL_NOTICE, "we don't support multi-octet length\n");
|
|
msgb_free(msg);
|
|
rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, &mctx);
|
|
return -EINVAL;
|
|
}
|
|
lctx.n201 = n201;
|
|
lctx.length = msg->l2h[2] >> 2;
|
|
lctx.more = !!(msg->l2h[2] & LAPDm_MORE);
|
|
msg->l3h = msg->l2h + 3;
|
|
msgb_pull_to_l3(msg);
|
|
}
|
|
/* store context for messages from lapd */
|
|
memcpy(&mctx.dl->mctx, &mctx, sizeof(mctx.dl->mctx));
|
|
rc =lapdm_rx_not_permitted(le, &lctx);
|
|
if (rc > 0) {
|
|
LOGDL(lctx.dl, LOGL_NOTICE, "received message not permitted\n");
|
|
msgb_free(msg);
|
|
rsl_rll_error(rc, &mctx);
|
|
return -EINVAL;
|
|
}
|
|
/* send to LAPD */
|
|
rc = lapd_ph_data_ind(msg, &lctx);
|
|
break;
|
|
case LAPDm_FMT_Bter:
|
|
/* FIXME */
|
|
msgb_free(msg);
|
|
break;
|
|
case LAPDm_FMT_Bbis:
|
|
/* directly pass up to layer3 */
|
|
msg->l3h = msg->l2h;
|
|
msgb_pull_to_l3(msg);
|
|
rc = send_rslms_rll_l3(RSL_MT_UNIT_DATA_IND, &mctx, msg);
|
|
break;
|
|
default:
|
|
msgb_free(msg);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/* input into layer2 (from layer 1) */
|
|
static int l2_ph_rach_ind(struct lapdm_entity *le, uint8_t ra, uint32_t fn, uint8_t acc_delay)
|
|
{
|
|
struct abis_rsl_cchan_hdr *ch;
|
|
struct gsm48_req_ref req_ref;
|
|
struct gsm_time gt;
|
|
struct msgb *msg = msgb_alloc_headroom(512, 64, "RSL CHAN RQD");
|
|
|
|
if (!msg)
|
|
return -ENOMEM;
|
|
|
|
msg->l2h = msgb_push(msg, sizeof(*ch));
|
|
ch = (struct abis_rsl_cchan_hdr *)msg->l2h;
|
|
rsl_init_cchan_hdr(ch, RSL_MT_CHAN_RQD);
|
|
ch->chan_nr = RSL_CHAN_RACH;
|
|
|
|
/* generate a RSL CHANNEL REQUIRED message */
|
|
gsm_fn2gsmtime(>, fn);
|
|
req_ref.ra = ra;
|
|
req_ref.t1 = gt.t1; /* FIXME: modulo? */
|
|
req_ref.t2 = gt.t2;
|
|
req_ref.t3_low = gt.t3 & 7;
|
|
req_ref.t3_high = gt.t3 >> 3;
|
|
|
|
msgb_tv_fixed_put(msg, RSL_IE_REQ_REFERENCE, 3, (uint8_t *) &req_ref);
|
|
msgb_tv_put(msg, RSL_IE_ACCESS_DELAY, acc_delay);
|
|
|
|
return rslms_sendmsg(msg, le);
|
|
}
|
|
|
|
static int l2_ph_chan_conf(struct msgb *msg, struct lapdm_entity *le, uint32_t frame_nr);
|
|
|
|
/*! Receive a PH-SAP primitive from L1 */
|
|
int lapdm_phsap_up(struct osmo_prim_hdr *oph, struct lapdm_entity *le)
|
|
{
|
|
struct osmo_phsap_prim *pp = (struct osmo_phsap_prim *) oph;
|
|
int rc = 0;
|
|
|
|
if (oph->sap != SAP_GSM_PH) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "primitive for unknown SAP %u\n",
|
|
oph->sap);
|
|
rc = -ENODEV;
|
|
goto free;
|
|
}
|
|
|
|
switch (oph->primitive) {
|
|
case PRIM_PH_DATA:
|
|
if (oph->operation != PRIM_OP_INDICATION) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "PH_DATA is not INDICATION %u\n",
|
|
oph->operation);
|
|
rc = -ENODEV;
|
|
goto free;
|
|
}
|
|
rc = l2_ph_data_ind(oph->msg, le, pp->u.data.chan_nr,
|
|
pp->u.data.link_id);
|
|
break;
|
|
case PRIM_PH_RTS:
|
|
if (oph->operation != PRIM_OP_INDICATION) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "PH_RTS is not INDICATION %u\n",
|
|
oph->operation);
|
|
rc = -ENODEV;
|
|
goto free;
|
|
}
|
|
rc = l2_ph_data_conf(oph->msg, le);
|
|
break;
|
|
case PRIM_PH_RACH:
|
|
switch (oph->operation) {
|
|
case PRIM_OP_INDICATION:
|
|
rc = l2_ph_rach_ind(le, pp->u.rach_ind.ra, pp->u.rach_ind.fn,
|
|
pp->u.rach_ind.acc_delay);
|
|
break;
|
|
case PRIM_OP_CONFIRM:
|
|
rc = l2_ph_chan_conf(oph->msg, le, pp->u.rach_ind.fn);
|
|
break;
|
|
default:
|
|
rc = -EIO;
|
|
goto free;
|
|
}
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_ERROR, "Unknown primitive %u\n",
|
|
oph->primitive);
|
|
rc = -EINVAL;
|
|
goto free;
|
|
}
|
|
|
|
return rc;
|
|
|
|
free:
|
|
msgb_free(oph->msg);
|
|
return rc;
|
|
}
|
|
|
|
|
|
/* L3 -> L2 / RSLMS -> LAPDm */
|
|
|
|
/* Set LAPDm context for established connection */
|
|
static int set_lapdm_context(struct lapdm_datalink *dl, uint8_t chan_nr,
|
|
uint8_t link_id, int n201, uint8_t sapi)
|
|
{
|
|
memset(&dl->mctx, 0, sizeof(dl->mctx));
|
|
dl->mctx.dl = dl;
|
|
dl->mctx.chan_nr = chan_nr;
|
|
dl->mctx.link_id = link_id;
|
|
dl->dl.lctx.dl = &dl->dl;
|
|
dl->dl.lctx.n201 = n201;
|
|
dl->dl.lctx.sapi = sapi;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* L3 requests establishment of data link */
|
|
static int rslms_rx_rll_est_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
uint8_t chan_nr = rllh->chan_nr;
|
|
uint8_t link_id = rllh->link_id;
|
|
uint8_t sapi = rllh->link_id & 7;
|
|
struct tlv_parsed tv;
|
|
uint8_t length;
|
|
uint8_t n201 = (rllh->link_id & 0x40) ? N201_AB_SACCH : N201_AB_SDCCH;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
/* Set LAPDm context for established connection */
|
|
set_lapdm_context(dl, chan_nr, link_id, n201, sapi);
|
|
|
|
rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg) - sizeof(*rllh));
|
|
if (TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) {
|
|
msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO);
|
|
/* contention resolution establishment procedure */
|
|
if (sapi != 0) {
|
|
/* According to clause 6, the contention resolution
|
|
* procedure is only permitted with SAPI value 0 */
|
|
LOGDL(&dl->dl, LOGL_ERROR, "SAPI != 0 but contention"
|
|
"resolution (discarding)\n");
|
|
msgb_free(msg);
|
|
return send_rll_simple(RSL_MT_REL_IND, &dl->mctx);
|
|
}
|
|
/* transmit a SABM command with the P bit set to "1". The SABM
|
|
* command shall contain the layer 3 message unit */
|
|
length = TLVP_LEN(&tv, RSL_IE_L3_INFO);
|
|
} else {
|
|
/* normal establishment procedure */
|
|
msg->l3h = msg->l2h + sizeof(*rllh);
|
|
length = 0;
|
|
}
|
|
|
|
/* check if the layer3 message length exceeds N201 */
|
|
if (length > n201) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "frame too large: %d > N201(%d) "
|
|
"(discarding)\n", length, n201);
|
|
msgb_free(msg);
|
|
return send_rll_simple(RSL_MT_REL_IND, &dl->mctx);
|
|
}
|
|
|
|
/* Remove RLL header from msgb and set length to L3-info */
|
|
msgb_pull_to_l3(msg);
|
|
msgb_trim(msg, length);
|
|
|
|
/* prepare prim */
|
|
osmo_prim_init(&dp.oph, 0, PRIM_DL_EST, PRIM_OP_REQUEST, msg);
|
|
|
|
/* send to L2 */
|
|
return lapd_recv_dlsap(&dp, &dl->dl.lctx);
|
|
}
|
|
|
|
/* L3 requests transfer of unnumbered information */
|
|
static int rslms_rx_rll_udata_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct lapdm_entity *le = dl->entity;
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
uint8_t chan_nr = rllh->chan_nr;
|
|
uint8_t link_id = rllh->link_id;
|
|
uint8_t sapi = link_id & 7;
|
|
struct tlv_parsed tv;
|
|
int length, ui_bts;
|
|
|
|
if (!le) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "lapdm_datalink without entity error\n");
|
|
msgb_free(msg);
|
|
return -EMLINK;
|
|
}
|
|
ui_bts = (le->mode == LAPDM_MODE_BTS && (link_id & 0x40));
|
|
|
|
/* check if the layer3 message length exceeds N201 */
|
|
|
|
rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh));
|
|
|
|
if (TLVP_PRESENT(&tv, RSL_IE_TIMING_ADVANCE)) {
|
|
le->ta = *TLVP_VAL(&tv, RSL_IE_TIMING_ADVANCE);
|
|
}
|
|
if (TLVP_PRESENT(&tv, RSL_IE_MS_POWER)) {
|
|
le->tx_power = *TLVP_VAL(&tv, RSL_IE_MS_POWER);
|
|
}
|
|
if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "unit data request without message error\n");
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO);
|
|
length = TLVP_LEN(&tv, RSL_IE_L3_INFO);
|
|
/* check if the layer3 message length exceeds N201 */
|
|
if (length + ((link_id & 0x40) ? 4 : 2) + !ui_bts > 23) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "frame too large: %d > N201(%d) "
|
|
"(discarding)\n", length,
|
|
((link_id & 0x40) ? 18 : 20) + ui_bts);
|
|
msgb_free(msg);
|
|
return -EIO;
|
|
}
|
|
|
|
LOGDL(&dl->dl, LOGL_INFO, "sending unit data (tx_power=%d, ta=%d)\n", le->tx_power, le->ta);
|
|
|
|
/* Remove RLL header from msgb and set length to L3-info */
|
|
msgb_pull_to_l3(msg);
|
|
msgb_trim(msg, length);
|
|
|
|
/* Push L1 + LAPDm header on msgb */
|
|
msg->l2h = msgb_push(msg, 2 + !ui_bts);
|
|
msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, dl->dl.cr.loc2rem.cmd);
|
|
msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_UI, 0);
|
|
if (!ui_bts)
|
|
msg->l2h[2] = LAPDm_LEN(length);
|
|
if (link_id & 0x40) {
|
|
msg->l2h = msgb_push(msg, 2);
|
|
msg->l2h[0] = le->tx_power;
|
|
msg->l2h[1] = le->ta;
|
|
}
|
|
|
|
/* Tramsmit */
|
|
return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, 23);
|
|
}
|
|
|
|
/* L3 requests transfer of acknowledged information */
|
|
static int rslms_rx_rll_data_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
struct tlv_parsed tv;
|
|
int length;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh));
|
|
if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "data request without message error\n");
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO);
|
|
length = TLVP_LEN(&tv, RSL_IE_L3_INFO);
|
|
|
|
/* Remove RLL header from msgb and set length to L3-info */
|
|
msgb_pull_to_l3(msg);
|
|
msgb_trim(msg, length);
|
|
|
|
/* prepare prim */
|
|
osmo_prim_init(&dp.oph, 0, PRIM_DL_DATA, PRIM_OP_REQUEST, msg);
|
|
|
|
/* send to L2 */
|
|
return lapd_recv_dlsap(&dp, &dl->dl.lctx);
|
|
}
|
|
|
|
/* L3 requests suspension of data link */
|
|
static int rslms_rx_rll_susp_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
uint8_t sapi = rllh->link_id & 7;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
if (sapi != 0) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "SAPI != 0 while suspending\n");
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* prepare prim */
|
|
osmo_prim_init(&dp.oph, 0, PRIM_DL_SUSP, PRIM_OP_REQUEST, msg);
|
|
|
|
/* send to L2 */
|
|
return lapd_recv_dlsap(&dp, &dl->dl.lctx);
|
|
}
|
|
|
|
/* L3 requests resume of data link */
|
|
static int rslms_rx_rll_res_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
int msg_type = rllh->c.msg_type;
|
|
uint8_t chan_nr = rllh->chan_nr;
|
|
uint8_t link_id = rllh->link_id;
|
|
uint8_t sapi = rllh->link_id & 7;
|
|
struct tlv_parsed tv;
|
|
uint8_t length;
|
|
uint8_t n201 = (rllh->link_id & 0x40) ? N201_AB_SACCH : N201_AB_SDCCH;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
/* Set LAPDm context for established connection */
|
|
set_lapdm_context(dl, chan_nr, link_id, n201, sapi);
|
|
|
|
rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh));
|
|
if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) {
|
|
LOGDL(&dl->dl, LOGL_ERROR, "resume without message error\n");
|
|
msgb_free(msg);
|
|
return send_rll_simple(RSL_MT_REL_IND, &dl->mctx);
|
|
}
|
|
msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO);
|
|
length = TLVP_LEN(&tv, RSL_IE_L3_INFO);
|
|
|
|
/* Remove RLL header from msgb and set length to L3-info */
|
|
msgb_pull_to_l3(msg);
|
|
msgb_trim(msg, length);
|
|
|
|
/* prepare prim */
|
|
osmo_prim_init(&dp.oph, 0, (msg_type == RSL_MT_RES_REQ) ? PRIM_DL_RES
|
|
: PRIM_DL_RECON, PRIM_OP_REQUEST, msg);
|
|
|
|
/* send to L2 */
|
|
return lapd_recv_dlsap(&dp, &dl->dl.lctx);
|
|
}
|
|
|
|
/* L3 requests release of data link */
|
|
static int rslms_rx_rll_rel_req(struct msgb *msg, struct lapdm_datalink *dl)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
uint8_t mode = 0;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
/* get release mode */
|
|
if (rllh->data[0] == RSL_IE_RELEASE_MODE)
|
|
mode = rllh->data[1] & 1;
|
|
|
|
/* Pull rllh */
|
|
msgb_pull_to_l3(msg);
|
|
|
|
/* 04.06 3.8.3: No information field is permitted with the DISC
|
|
* command. */
|
|
msgb_trim(msg, 0);
|
|
|
|
/* prepare prim */
|
|
osmo_prim_init(&dp.oph, 0, PRIM_DL_REL, PRIM_OP_REQUEST, msg);
|
|
dp.u.rel_req.mode = mode;
|
|
|
|
/* send to L2 */
|
|
return lapd_recv_dlsap(&dp, &dl->dl.lctx);
|
|
}
|
|
|
|
/* L3 requests channel in idle state */
|
|
static int rslms_rx_chan_rqd(struct lapdm_channel *lc, struct msgb *msg)
|
|
{
|
|
struct abis_rsl_cchan_hdr *cch = msgb_l2(msg);
|
|
void *l1ctx = lc->lapdm_dcch.l1_ctx;
|
|
struct osmo_phsap_prim pp;
|
|
|
|
osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_RACH,
|
|
PRIM_OP_REQUEST, NULL);
|
|
|
|
if (msgb_l2len(msg) < sizeof(*cch) + 4 + 2 + 2) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Message too short for CHAN RQD!\n");
|
|
return -EINVAL;
|
|
}
|
|
if (cch->data[0] != RSL_IE_REQ_REFERENCE) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Missing REQ REFERENCE IE\n");
|
|
return -EINVAL;
|
|
}
|
|
pp.u.rach_req.ra = cch->data[1];
|
|
pp.u.rach_req.offset = ((cch->data[2] & 0x7f) << 8) | cch->data[3];
|
|
pp.u.rach_req.is_combined_ccch = cch->data[2] >> 7;
|
|
|
|
if (cch->data[4] != RSL_IE_ACCESS_DELAY) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Missing ACCESS_DELAY IE\n");
|
|
return -EINVAL;
|
|
}
|
|
/* TA = 0 - delay */
|
|
pp.u.rach_req.ta = 0 - cch->data[5];
|
|
|
|
if (cch->data[6] != RSL_IE_MS_POWER) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Missing MS POWER IE\n");
|
|
return -EINVAL;
|
|
}
|
|
pp.u.rach_req.tx_power = cch->data[7];
|
|
|
|
msgb_free(msg);
|
|
|
|
return lc->lapdm_dcch.l1_prim_cb(&pp.oph, l1ctx);
|
|
}
|
|
|
|
/* L1 confirms channel request */
|
|
static int l2_ph_chan_conf(struct msgb *msg, struct lapdm_entity *le, uint32_t frame_nr)
|
|
{
|
|
struct abis_rsl_cchan_hdr *ch;
|
|
struct gsm_time tm;
|
|
struct gsm48_req_ref *ref;
|
|
|
|
gsm_fn2gsmtime(&tm, frame_nr);
|
|
|
|
msgb_pull_to_l3(msg);
|
|
msg->l2h = msgb_push(msg, sizeof(*ch) + sizeof(*ref));
|
|
ch = (struct abis_rsl_cchan_hdr *)msg->l2h;
|
|
rsl_init_cchan_hdr(ch, RSL_MT_CHAN_CONF);
|
|
ch->chan_nr = RSL_CHAN_RACH;
|
|
ch->data[0] = RSL_IE_REQ_REFERENCE;
|
|
ref = (struct gsm48_req_ref *) (ch->data + 1);
|
|
ref->t1 = tm.t1;
|
|
ref->t2 = tm.t2;
|
|
ref->t3_low = tm.t3 & 0x7;
|
|
ref->t3_high = tm.t3 >> 3;
|
|
|
|
return rslms_sendmsg(msg, le);
|
|
}
|
|
|
|
/* incoming RSLms RLL message from L3 */
|
|
static int rslms_rx_rll(struct msgb *msg, struct lapdm_channel *lc)
|
|
{
|
|
struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
|
|
int msg_type = rllh->c.msg_type;
|
|
uint8_t sapi = rllh->link_id & 7;
|
|
struct lapdm_entity *le;
|
|
struct lapdm_datalink *dl;
|
|
int rc = 0;
|
|
|
|
if (msgb_l2len(msg) < sizeof(*rllh)) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Message too short for RLL hdr!\n");
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (rllh->link_id & 0x40)
|
|
le = &lc->lapdm_acch;
|
|
else
|
|
le = &lc->lapdm_dcch;
|
|
|
|
/* 4.1.1.5 / 4.1.1.6 / 4.1.1.7 all only exist on MS side, not
|
|
* BTS side */
|
|
if (le->mode == LAPDM_MODE_BTS) {
|
|
switch (msg_type) {
|
|
case RSL_MT_SUSP_REQ:
|
|
case RSL_MT_RES_REQ:
|
|
case RSL_MT_RECON_REQ:
|
|
LOGP(DLLAPD, LOGL_NOTICE, "(%s) RLL Message '%s' unsupported in BTS side LAPDm\n",
|
|
lc->name, rsl_msg_name(msg_type));
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* G.2.1 No action shall be taken on frames containing an unallocated
|
|
* SAPI.
|
|
*/
|
|
dl = lapdm_datalink_for_sapi(le, sapi);
|
|
if (!dl) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "No instance for SAPI %d!\n", sapi);
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
switch (msg_type) {
|
|
case RSL_MT_DATA_REQ:
|
|
case RSL_MT_SUSP_REQ:
|
|
case RSL_MT_REL_REQ:
|
|
/* This is triggered in abnormal error conditions where
|
|
* set_lapdm_context() was not called for the channel earlier. */
|
|
if (!dl->dl.lctx.dl) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "(%s) RLL Message '%s' received without LAPDm context. (sapi %d)\n",
|
|
lc->name, rsl_msg_name(msg_type), sapi);
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_INFO, "(%s) RLL Message '%s' received. (sapi %d)\n",
|
|
lc->name, rsl_msg_name(msg_type), sapi);
|
|
}
|
|
|
|
switch (msg_type) {
|
|
case RSL_MT_UNIT_DATA_REQ:
|
|
rc = rslms_rx_rll_udata_req(msg, dl);
|
|
break;
|
|
case RSL_MT_EST_REQ:
|
|
rc = rslms_rx_rll_est_req(msg, dl);
|
|
break;
|
|
case RSL_MT_DATA_REQ:
|
|
rc = rslms_rx_rll_data_req(msg, dl);
|
|
break;
|
|
case RSL_MT_SUSP_REQ:
|
|
rc = rslms_rx_rll_susp_req(msg, dl);
|
|
break;
|
|
case RSL_MT_RES_REQ:
|
|
rc = rslms_rx_rll_res_req(msg, dl);
|
|
break;
|
|
case RSL_MT_RECON_REQ:
|
|
rc = rslms_rx_rll_res_req(msg, dl);
|
|
break;
|
|
case RSL_MT_REL_REQ:
|
|
rc = rslms_rx_rll_rel_req(msg, dl);
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Message unsupported.\n");
|
|
msgb_free(msg);
|
|
rc = -EINVAL;
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/* incoming RSLms COMMON CHANNEL message from L3 */
|
|
static int rslms_rx_com_chan(struct msgb *msg, struct lapdm_channel *lc)
|
|
{
|
|
struct abis_rsl_cchan_hdr *cch = msgb_l2(msg);
|
|
int msg_type = cch->c.msg_type;
|
|
int rc = 0;
|
|
|
|
if (msgb_l2len(msg) < sizeof(*cch)) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Message too short for COM CHAN hdr!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
switch (msg_type) {
|
|
case RSL_MT_CHAN_RQD:
|
|
/* create and send RACH request */
|
|
rc = rslms_rx_chan_rqd(lc, msg);
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Unknown COMMON CHANNEL msg %d!\n",
|
|
msg_type);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*! Receive a RSLms \ref msgb from Layer 3. 'msg' ownership is transferred,
|
|
* i.e. caller must not free it */
|
|
int lapdm_rslms_recvmsg(struct msgb *msg, struct lapdm_channel *lc)
|
|
{
|
|
struct abis_rsl_common_hdr *rslh = msgb_l2(msg);
|
|
int rc = 0;
|
|
|
|
if (msgb_l2len(msg) < sizeof(*rslh)) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "Message too short RSL hdr!\n");
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
switch (rslh->msg_discr & 0xfe) {
|
|
case ABIS_RSL_MDISC_RLL:
|
|
rc = rslms_rx_rll(msg, lc);
|
|
break;
|
|
case ABIS_RSL_MDISC_COM_CHAN:
|
|
rc = rslms_rx_com_chan(msg, lc);
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_ERROR, "unknown RSLms message "
|
|
"discriminator 0x%02x", rslh->msg_discr);
|
|
msgb_free(msg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*! Set the \ref lapdm_mode of a LAPDm entity */
|
|
int lapdm_entity_set_mode(struct lapdm_entity *le, enum lapdm_mode mode)
|
|
{
|
|
int i;
|
|
enum lapd_mode lm;
|
|
|
|
switch (mode) {
|
|
case LAPDM_MODE_MS:
|
|
lm = LAPD_MODE_USER;
|
|
break;
|
|
case LAPDM_MODE_BTS:
|
|
lm = LAPD_MODE_NETWORK;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
for (i = 0; i < ARRAY_SIZE(le->datalink); i++) {
|
|
lapd_set_mode(&le->datalink[i].dl, lm);
|
|
}
|
|
|
|
le->mode = mode;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*! Set the \ref lapdm_mode of a LAPDm channel*/
|
|
int lapdm_channel_set_mode(struct lapdm_channel *lc, enum lapdm_mode mode)
|
|
{
|
|
int rc;
|
|
|
|
rc = lapdm_entity_set_mode(&lc->lapdm_dcch, mode);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
return lapdm_entity_set_mode(&lc->lapdm_acch, mode);
|
|
}
|
|
|
|
/*! Set the L1 callback and context of a LAPDm channel */
|
|
void lapdm_channel_set_l1(struct lapdm_channel *lc, osmo_prim_cb cb, void *ctx)
|
|
{
|
|
lc->lapdm_dcch.l1_prim_cb = cb;
|
|
lc->lapdm_acch.l1_prim_cb = cb;
|
|
lc->lapdm_dcch.l1_ctx = ctx;
|
|
lc->lapdm_acch.l1_ctx = ctx;
|
|
}
|
|
|
|
/*! Set the L3 callback and context of a LAPDm channel */
|
|
void lapdm_channel_set_l3(struct lapdm_channel *lc, lapdm_cb_t cb, void *ctx)
|
|
{
|
|
lc->lapdm_dcch.l3_cb = cb;
|
|
lc->lapdm_acch.l3_cb = cb;
|
|
lc->lapdm_dcch.l3_ctx = ctx;
|
|
lc->lapdm_acch.l3_ctx = ctx;
|
|
}
|
|
|
|
/*! Reset an entire LAPDm entity and all its datalinks */
|
|
void lapdm_entity_reset(struct lapdm_entity *le)
|
|
{
|
|
struct lapdm_datalink *dl;
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(le->datalink); i++) {
|
|
dl = &le->datalink[i];
|
|
lapd_dl_reset(&dl->dl);
|
|
}
|
|
}
|
|
|
|
/*! Reset a LAPDm channel with all its entities */
|
|
void lapdm_channel_reset(struct lapdm_channel *lc)
|
|
{
|
|
lapdm_entity_reset(&lc->lapdm_dcch);
|
|
lapdm_entity_reset(&lc->lapdm_acch);
|
|
}
|
|
|
|
/*! Set the flags of a LAPDm entity */
|
|
void lapdm_entity_set_flags(struct lapdm_entity *le, unsigned int flags)
|
|
{
|
|
le->flags = flags;
|
|
}
|
|
|
|
/*! Set the flags of all LAPDm entities in a LAPDm channel */
|
|
void lapdm_channel_set_flags(struct lapdm_channel *lc, unsigned int flags)
|
|
{
|
|
lapdm_entity_set_flags(&lc->lapdm_dcch, flags);
|
|
lapdm_entity_set_flags(&lc->lapdm_acch, flags);
|
|
}
|
|
|
|
/*! @} */
|