| /*! \file lapdm.c |
| * GSM LAPDm (TS 04.06) implementation. */ |
| /* |
| * (C) 2010-2019 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2010-2011 by Andreas Eversberg <jolly@eversberg.eu> |
| * (C) 2014-2016 by sysmocom - s.f.m.c GmbH |
| * |
| * All Rights Reserved |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| /*! \addtogroup lapdm |
| * @{ |
| * \file lapdm.c */ |
| |
| #include <stdio.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/timer.h> |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/core/utils.h> |
| |
| #include <osmocom/gsm/tlv.h> |
| #include <osmocom/gsm/rsl.h> |
| #include <osmocom/gsm/prim.h> |
| #include <osmocom/gsm/gsm_utils.h> |
| #include <osmocom/gsm/lapdm.h> |
| |
| #include <osmocom/gsm/protocol/gsm_04_08.h> |
| #include <osmocom/gsm/protocol/gsm_08_58.h> |
| |
| #define LAPD_U_SABM 0x7 |
| |
| /* TS 04.06 Figure 4 / Section 3.2 */ |
| #define LAPDm_LPD_NORMAL 0 |
| #define LAPDm_LPD_SMSCB 1 |
| #define LAPDm_SAPI_NORMAL 0 |
| #define LAPDm_SAPI_SMS 3 |
| #define LAPDm_ADDR(lpd, sapi, cr) ((((lpd) & 0x3) << 5) | (((sapi) & 0x7) << 2) | (((cr) & 0x1) << 1) | 0x1) |
| |
| #define LAPDm_ADDR_LPD(addr) (((addr) >> 5) & 0x3) |
| #define LAPDm_ADDR_SAPI(addr) (((addr) >> 2) & 0x7) |
| #define LAPDm_ADDR_CR(addr) (((addr) >> 1) & 0x1) |
| #define LAPDm_ADDR_EA(addr) ((addr) & 0x1) |
| |
| /* TS 04.06 Table 3 / Section 3.4.3 */ |
| #define LAPDm_CTRL_I(nr, ns, p) ((((nr) & 0x7) << 5) | (((p) & 0x1) << 4) | (((ns) & 0x7) << 1)) |
| #define LAPDm_CTRL_S(nr, s, p) ((((nr) & 0x7) << 5) | (((p) & 0x1) << 4) | (((s) & 0x3) << 2) | 0x1) |
| #define LAPDm_CTRL_U(u, p) ((((u) & 0x1c) << (5-2)) | (((p) & 0x1) << 4) | (((u) & 0x3) << 2) | 0x3) |
| |
| #define LAPDm_CTRL_is_I(ctrl) (((ctrl) & 0x1) == 0) |
| #define LAPDm_CTRL_is_S(ctrl) (((ctrl) & 0x3) == 1) |
| #define LAPDm_CTRL_is_U(ctrl) (((ctrl) & 0x3) == 3) |
| |
| #define LAPDm_CTRL_U_BITS(ctrl) ((((ctrl) & 0xC) >> 2) | ((ctrl) & 0xE0) >> 3) |
| #define LAPDm_CTRL_PF_BIT(ctrl) (((ctrl) >> 4) & 0x1) |
| |
| #define LAPDm_CTRL_S_BITS(ctrl) (((ctrl) & 0xC) >> 2) |
| |
| #define LAPDm_CTRL_I_Ns(ctrl) (((ctrl) & 0xE) >> 1) |
| #define LAPDm_CTRL_Nr(ctrl) (((ctrl) & 0xE0) >> 5) |
| |
| #define LAPDm_LEN(len) ((len << 2) | 0x1) |
| #define LAPDm_MORE 0x2 |
| #define LAPDm_EL 0x1 |
| |
| #define LAPDm_U_UI 0x0 |
| |
| /* TS 04.06 Section 5.8.3 */ |
| #define N201_AB_SACCH 18 |
| #define N201_AB_SDCCH 20 |
| #define N201_AB_FACCH 20 |
| #define N201_Bbis 23 |
| #define N201_Bter_SACCH 21 |
| #define N201_Bter_SDCCH 23 |
| #define N201_Bter_FACCH 23 |
| #define N201_B4 19 |
| |
| /* 5.8.2.1 N200 during establish and release */ |
| #define N200_EST_REL 5 |
| /* 5.8.2.1 N200 during timer recovery state */ |
| #define N200_TR_SACCH 5 |
| #define N200_TR_SDCCH 23 |
| #define N200_TR_FACCH_FR 34 |
| #define N200_TR_EFACCH_FR 48 |
| #define N200_TR_FACCH_HR 29 |
| /* FIXME: set N200 depending on chan_nr */ |
| #define N200 N200_TR_SDCCH |
| |
| enum lapdm_format { |
| LAPDm_FMT_A, |
| LAPDm_FMT_B, |
| LAPDm_FMT_Bbis, |
| LAPDm_FMT_Bter, |
| LAPDm_FMT_B4, |
| }; |
| |
| const struct value_string osmo_ph_prim_names[] = { |
| { PRIM_PH_DATA, "PH-DATA" }, |
| { PRIM_PH_RACH, "PH-RANDOM_ACCESS" }, |
| { PRIM_PH_CONN, "PH-CONNECT" }, |
| { PRIM_PH_EMPTY_FRAME, "PH-EMPTY_FRAME" }, |
| { PRIM_PH_RTS, "PH-RTS" }, |
| { PRIM_MPH_INFO, "MPH-INFO" }, |
| { PRIM_TCH, "TCH" }, |
| { PRIM_TCH_RTS, "TCH-RTS" }, |
| { 0, NULL } |
| }; |
| |
| extern void *tall_lapd_ctx; |
| |
| static int lapdm_send_ph_data_req(struct lapd_msg_ctx *lctx, struct msgb *msg); |
| static int send_rslms_dlsap(struct osmo_dlsap_prim *dp, |
| struct lapd_msg_ctx *lctx); |
| static int update_pending_frames(struct lapd_msg_ctx *lctx); |
| |
| static void lapdm_dl_init(struct lapdm_datalink *dl, |
| struct lapdm_entity *entity, int t200_ms, uint32_t n200, |
| const char *name) |
| { |
| memset(dl, 0, sizeof(*dl)); |
| dl->entity = entity; |
| lapd_dl_init2(&dl->dl, 1, 8, 251, name); /* Section 5.8.5 of TS 04.06 */ |
| dl->dl.reestablish = 0; /* GSM uses no reestablish */ |
| dl->dl.send_ph_data_req = lapdm_send_ph_data_req; |
| dl->dl.send_dlsap = send_rslms_dlsap; |
| dl->dl.update_pending_frames = update_pending_frames; |
| dl->dl.n200_est_rel = N200_EST_REL; |
| dl->dl.n200 = n200; |
| dl->dl.t203_sec = 0; dl->dl.t203_usec = 0; |
| dl->dl.t200_sec = t200_ms / 1000; dl->dl.t200_usec = (t200_ms % 1000) * 1000; |
| } |
| |
| /*! initialize a LAPDm entity and all datalinks inside |
| * \param[in] le LAPDm entity |
| * \param[in] mode \ref lapdm_mode (BTS/MS) |
| * \param[in] t200 T200 re-transmission timer for all SAPIs in seconds |
| * |
| * Don't use this function; It doesn't support different T200 values per API |
| * and doesn't permit the caller to specify the N200 counter, both of which |
| * are required by GSM specs and supported by lapdm_entity_init2(). |
| */ |
| void lapdm_entity_init(struct lapdm_entity *le, enum lapdm_mode mode, int t200) |
| { |
| /* convert from single full-second value to per-SAPI milli-second value */ |
| int t200_ms_sapi_arr[_NR_DL_SAPI]; |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(t200_ms_sapi_arr); i++) |
| t200_ms_sapi_arr[i] = t200 * 1000; |
| |
| return lapdm_entity_init3(le, mode, t200_ms_sapi_arr, N200, NULL); |
| } |
| |
| /*! initialize a LAPDm entity and all datalinks inside |
| * \param[in] le LAPDm entity |
| * \param[in] mode lapdm_mode (BTS/MS) |
| * \param[in] t200_ms per-SAPI array of T200 re-transmission timer in milli-seconds |
| * \param[in] n200 N200 re-transmisison count |
| */ |
| void lapdm_entity_init2(struct lapdm_entity *le, enum lapdm_mode mode, |
| const int *t200_ms, int n200) |
| { |
| lapdm_entity_init3(le, mode, t200_ms, n200, NULL); |
| } |
| |
| /*! initialize a LAPDm entity and all datalinks inside |
| * \param[in] le LAPDm entity |
| * \param[in] mode lapdm_mode (BTS/MS) |
| * \param[in] t200_ms per-SAPI array of T200 re-transmission timer in milli-seconds |
| * \param[in] n200 N200 re-transmisison count |
| * \param[in] name human-readable name (will be copied internally + extended with SAPI) |
| */ |
| void lapdm_entity_init3(struct lapdm_entity *le, enum lapdm_mode mode, |
| const int *t200_ms, int n200, const char *name_pfx) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < ARRAY_SIZE(le->datalink); i++) { |
| char name[256]; |
| if (name_pfx) { |
| snprintf(name, sizeof(name), "%s[%s]", name_pfx, i == 0 ? "0" : "3"); |
| lapdm_dl_init(&le->datalink[i], le, t200_ms[i], n200, name); |
| } else |
| lapdm_dl_init(&le->datalink[i], le, t200_ms[i], n200, NULL); |
| } |
| |
| lapdm_entity_set_mode(le, mode); |
| } |
| |
| static int get_n200_dcch(enum gsm_chan_t chan_t) |
| { |
| switch (chan_t) { |
| case GSM_LCHAN_SDCCH: |
| return N200_TR_SDCCH; |
| case GSM_LCHAN_TCH_F: |
| return N200_TR_FACCH_FR; |
| case GSM_LCHAN_TCH_H: |
| return N200_TR_FACCH_HR; |
| default: |
| return -1; |
| } |
| } |
| |
| /*! initialize a LAPDm channel and all its channels |
| * \param[in] lc lapdm_channel to be initialized |
| * \param[in] mode lapdm_mode (BTS/MS) |
| * |
| * Don't use this function; It doesn't support different T200 values per API |
| * and doesn't set the correct N200 counter, both of which |
| * are required by GSM specs and supported by lapdm_channel_init2(). |
| */ |
| void lapdm_channel_init(struct lapdm_channel *lc, enum lapdm_mode mode) |
| { |
| /* emulate old backwards-compatible behavior with 1s/2s */ |
| const int t200_ms_dcch[_NR_DL_SAPI] = { 1000, 1000 }; |
| const int t200_ms_acch[_NR_DL_SAPI] = { 2000, 2000 }; |
| |
| lapdm_channel_init3(lc, mode, t200_ms_dcch, t200_ms_acch, GSM_LCHAN_SDCCH, NULL); |
| } |
| |
| /*! initialize a LAPDm channel and all its channels |
| * \param[in] lc \ref lapdm_channel to be initialized |
| * \param[in] mode \ref lapdm_mode (BTS/MS) |
| * \param[in] t200_ms_dcch per-SAPI array of T200 in milli-seconds for DCCH |
| * \param[in] t200_ms_acch per-SAPI array of T200 in milli-seconds for SACCH |
| * \param[in] chan_t GSM channel type (to correctly set N200) |
| */ |
| int lapdm_channel_init2(struct lapdm_channel *lc, enum lapdm_mode mode, |
| const int *t200_ms_dcch, const int *t200_ms_acch, enum gsm_chan_t chan_t) |
| { |
| return lapdm_channel_init3(lc, mode, t200_ms_dcch, t200_ms_acch, chan_t, NULL); |
| } |
| |
| /*! initialize a LAPDm channel and all its channels |
| * \param[in] lc \ref lapdm_channel to be initialized |
| * \param[in] mode \ref lapdm_mode (BTS/MS) |
| * \param[in] t200_ms_dcch per-SAPI array of T200 in milli-seconds for DCCH |
| * \param[in] t200_ms_acch per-SAPI array of T200 in milli-seconds for SACCH |
| * \param[in] chan_t GSM channel type (to correctly set N200) |
| * \parma[in] name_pfx human-readable name (copied by function + extended with ACCH/DCCH) |
| */ |
| int lapdm_channel_init3(struct lapdm_channel *lc, enum lapdm_mode mode, |
| const int *t200_ms_dcch, const int *t200_ms_acch, enum gsm_chan_t chan_t, |
| const char *name_pfx) |
| { |
| int n200_dcch = get_n200_dcch(chan_t); |
| char namebuf[256]; |
| char *name = NULL; |
| |
| if (n200_dcch < 0) |
| return -EINVAL; |
| |
| osmo_talloc_replace_string(tall_lapd_ctx, &lc->name, name_pfx); |
| |
| if (name_pfx) { |
| snprintf(namebuf, sizeof(namebuf), "%s[ACCH]", name_pfx); |
| name = namebuf; |
| } |
| lapdm_entity_init3(&lc->lapdm_acch, mode, t200_ms_acch, N200_TR_SACCH, name); |
| lc->lapdm_acch.lapdm_ch = lc; |
| |
| if (name_pfx) { |
| snprintf(namebuf, sizeof(namebuf), "%s[DCCH]", name_pfx); |
| name = namebuf; |
| } |
| lapdm_entity_init3(&lc->lapdm_dcch, mode, t200_ms_dcch, n200_dcch, name); |
| lc->lapdm_dcch.lapdm_ch = lc; |
| |
| return 0; |
| } |
| |
| /*! flush and release all resoures in LAPDm entity */ |
| void lapdm_entity_exit(struct lapdm_entity *le) |
| { |
| unsigned int i; |
| struct lapdm_datalink *dl; |
| |
| for (i = 0; i < ARRAY_SIZE(le->datalink); i++) { |
| dl = &le->datalink[i]; |
| lapd_dl_exit(&dl->dl); |
| } |
| } |
| |
| /* lfush and release all resources in LAPDm channel |
| * |
| * A convenience wrapper calling \ref lapdm_entity_exit on both |
| * entities inside the \ref lapdm_channel |
| */ |
| void lapdm_channel_exit(struct lapdm_channel *lc) |
| { |
| lapdm_entity_exit(&lc->lapdm_acch); |
| lapdm_entity_exit(&lc->lapdm_dcch); |
| } |
| |
| struct lapdm_datalink *lapdm_datalink_for_sapi(struct lapdm_entity *le, uint8_t sapi) |
| { |
| switch (sapi) { |
| case LAPDm_SAPI_NORMAL: |
| return &le->datalink[0]; |
| case LAPDm_SAPI_SMS: |
| return &le->datalink[1]; |
| default: |
| return NULL; |
| } |
| } |
| |
| /* Append padding (if required) */ |
| static void lapdm_pad_msgb(struct msgb *msg, uint8_t n201) |
| { |
| int pad_len = n201 - msgb_l2len(msg); |
| uint8_t *data; |
| |
| if (pad_len < 0) { |
| LOGP(DLLAPD, LOGL_ERROR, |
| "cannot pad message that is already too big!\n"); |
| return; |
| } |
| |
| data = msgb_put(msg, pad_len); /* TODO: random padding */ |
| memset(data, GSM_MACBLOCK_PADDING, pad_len); |
| } |
| |
| /* input function that L2 calls when sending messages up to L3 */ |
| static int rslms_sendmsg(struct msgb *msg, struct lapdm_entity *le) |
| { |
| if (!le->l3_cb) { |
| msgb_free(msg); |
| return -EIO; |
| } |
| |
| /* call the layer2 message handler that is registered */ |
| return le->l3_cb(msg, le, le->l3_ctx); |
| } |
| |
| /* write a frame into the tx queue */ |
| static int tx_ph_data_enqueue(struct lapdm_datalink *dl, struct msgb *msg, |
| uint8_t chan_nr, uint8_t link_id, uint8_t pad) |
| { |
| struct lapdm_entity *le = dl->entity; |
| struct osmo_phsap_prim pp; |
| |
| /* if there is a pending message, queue it */ |
| if (le->tx_pending || le->flags & LAPDM_ENT_F_POLLING_ONLY) { |
| *msgb_push(msg, 1) = pad; |
| *msgb_push(msg, 1) = link_id; |
| *msgb_push(msg, 1) = chan_nr; |
| msgb_enqueue(&dl->dl.tx_queue, msg); |
| return -EBUSY; |
| } |
| |
| osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_DATA, |
| PRIM_OP_REQUEST, msg); |
| pp.u.data.chan_nr = chan_nr; |
| pp.u.data.link_id = link_id; |
| |
| /* send the frame now */ |
| le->tx_pending = 0; /* disabled flow control */ |
| lapdm_pad_msgb(msg, pad); |
| |
| return le->l1_prim_cb(&pp.oph, le->l1_ctx); |
| } |
| |
| /* Dequeue a Downlink message for DCCH (dedicated channel) */ |
| static struct msgb *tx_dequeue_dcch_msgb(struct lapdm_entity *le) |
| { |
| struct msgb *msg; |
| |
| /* SAPI=0 always has higher priority than SAPI=3 */ |
| msg = msgb_dequeue(&le->datalink[DL_SAPI0].dl.tx_queue); |
| if (msg == NULL) /* no SAPI=0 messages, dequeue SAPI=3 (if any) */ |
| msg = msgb_dequeue(&le->datalink[DL_SAPI3].dl.tx_queue); |
| |
| return msg; |
| } |
| |
| /* Dequeue a Downlink message for ACCH (associated channel) */ |
| static struct msgb *tx_dequeue_acch_msgb(struct lapdm_entity *le) |
| { |
| struct lapdm_datalink *dl; |
| int last = le->last_tx_dequeue; |
| int i = last, n = ARRAY_SIZE(le->datalink); |
| struct msgb *msg = NULL; |
| |
| /* round-robin dequeue */ |
| do { |
| /* next */ |
| i = (i + 1) % n; |
| dl = &le->datalink[i]; |
| if ((msg = msgb_dequeue(&dl->dl.tx_queue))) |
| break; |
| } while (i != last); |
| |
| if (msg) { |
| /* Set last dequeue position */ |
| le->last_tx_dequeue = i; |
| } |
| |
| return msg; |
| } |
| |
| /*! dequeue a msg that's pending transmission via L1 and wrap it into |
| * a osmo_phsap_prim */ |
| int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp) |
| { |
| struct msgb *msg; |
| uint8_t pad; |
| |
| /* Dequeue depending on channel type: DCCH or ACCH. |
| * See 3GPP TS 44.005, section 4.2.2 "Priority". */ |
| 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); |
| } |
| |
| /*! @} */ |