| /* GSM LAPDm (TS 04.06) implementation */ |
| |
| /* (C) 2010-2011 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2010 by Andreas Eversberg <jolly@eversberg.eu> |
| * |
| * All Rights Reserved |
| * |
| * 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 */ |
| |
| /*! |
| * Notes on Buffering: rcv_buffer, tx_queue, tx_hist, send_buffer, send_queue |
| * |
| * RX data is stored in the rcv_buffer (pointer). If the message is complete, it |
| * is removed from rcv_buffer pointer and forwarded to L3. If the RX data is |
| * received while there is an incomplete rcv_buffer, it is appended to it. |
| * |
| * TX data is stored in the send_queue first. When transmitting a frame, |
| * the first message in the send_queue is moved to the send_buffer. There it |
| * resides until all fragments are acknowledged. Fragments to be sent by I |
| * frames are stored in the tx_hist buffer for resend, if required. Also the |
| * current fragment is copied into the tx_queue. There it resides until it is |
| * forwarded to layer 1. |
| * |
| * In case we have SAPI 0, we only have a window size of 1, so the unack- |
| * nowledged message resides always in the send_buffer. In case of a suspend, |
| * it can be written back to the first position of the send_queue. |
| * |
| * The layer 1 normally sends a PH-READY-TO-SEND. But because we use |
| * asynchronous transfer between layer 1 and layer 2 (serial link), we must |
| * send a frame before layer 1 reaches the right timeslot to send it. So we |
| * move the tx_queue to layer 1 when there is not already a pending frame, and |
| * wait until acknowledge after the frame has been sent. If we receive an |
| * acknowledge, we can send the next frame from the buffer, if any. |
| * |
| * The moving of tx_queue to layer 1 may also trigger T200, if desired. Also it |
| * will trigger next I frame, if possible. |
| * |
| */ |
| |
| #include <stdio.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <errno.h> |
| #include <arpa/inet.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> |
| |
| /* 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_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) |
| |
| /* TS 04.06 Table 4 / Section 3.8.1 */ |
| #define LAPDm_U_SABM 0x7 |
| #define LAPDm_U_DM 0x3 |
| #define LAPDm_U_UI 0x0 |
| #define LAPDm_U_DISC 0x8 |
| #define LAPDm_U_UA 0xC |
| |
| #define LAPDm_S_RR 0x0 |
| #define LAPDm_S_RNR 0x1 |
| #define LAPDm_S_REJ 0x2 |
| |
| #define LAPDm_LEN(len) ((len << 2) | 0x1) |
| #define LAPDm_MORE 0x2 |
| |
| /* 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: this depends on chan type */ |
| #define N200 N200_TR_SACCH |
| |
| #define CR_MS2BS_CMD 0 |
| #define CR_MS2BS_RESP 1 |
| #define CR_BS2MS_CMD 1 |
| #define CR_BS2MS_RESP 0 |
| |
| /* Set T200 to 1 Second (OpenBTS uses 900ms) */ |
| #define T200 1, 0 |
| |
| /* k value for each SAPI */ |
| static uint8_t k_sapi[] = {1, 1, 1, 1, 1, 1, 1, 1}; |
| |
| enum lapdm_format { |
| LAPDm_FMT_A, |
| LAPDm_FMT_B, |
| LAPDm_FMT_Bbis, |
| LAPDm_FMT_Bter, |
| LAPDm_FMT_B4, |
| }; |
| |
| static void lapdm_t200_cb(void *data); |
| static int rslms_send_i(struct lapdm_msg_ctx *mctx, int line); |
| |
| /* UTILITY FUNCTIONS */ |
| |
| static inline uint8_t inc_mod8(uint8_t x) |
| { |
| return (x + 1) & 7; |
| } |
| |
| static inline uint8_t add_mod8(uint8_t x, uint8_t y) |
| { |
| return (x + y) & 7; |
| } |
| |
| static inline uint8_t sub_mod8(uint8_t x, uint8_t y) |
| { |
| return (x - y) & 7; /* handle negative results correctly */ |
| } |
| |
| static void lapdm_dl_init(struct lapdm_datalink *dl, |
| struct lapdm_entity *entity) |
| { |
| memset(dl, 0, sizeof(*dl)); |
| INIT_LLIST_HEAD(&dl->send_queue); |
| INIT_LLIST_HEAD(&dl->tx_queue); |
| dl->state = LAPDm_STATE_IDLE; |
| dl->t200.data = dl; |
| dl->t200.cb = &lapdm_t200_cb; |
| dl->entity = entity; |
| } |
| |
| /*! \brief initialize a LAPDm entity and all datalinks inside |
| * \param[in] le LAPDm entity |
| * \param[in] mode \ref lapdm_mode (BTS/MS) |
| */ |
| void lapdm_entity_init(struct lapdm_entity *le, enum lapdm_mode mode) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < ARRAY_SIZE(le->datalink); i++) |
| lapdm_dl_init(&le->datalink[i], le); |
| |
| lapdm_entity_set_mode(le, mode); |
| } |
| |
| /*! \brief 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) |
| * |
| * This really is a convenience wrapper around calling \ref |
| * lapdm_entity_init twice. |
| */ |
| void lapdm_channel_init(struct lapdm_channel *lc, enum lapdm_mode mode) |
| { |
| lapdm_entity_init(&lc->lapdm_acch, mode); |
| lapdm_entity_init(&lc->lapdm_dcch, mode); |
| } |
| |
| static void lapdm_dl_flush_send(struct lapdm_datalink *dl) |
| { |
| struct msgb *msg; |
| |
| /* Flush send-queue */ |
| while ((msg = msgb_dequeue(&dl->send_queue))) |
| msgb_free(msg); |
| |
| /* Clear send-buffer */ |
| if (dl->send_buffer) { |
| msgb_free(dl->send_buffer); |
| dl->send_buffer = NULL; |
| } |
| } |
| |
| static void lapdm_dl_flush_tx(struct lapdm_datalink *dl) |
| { |
| struct msgb *msg; |
| unsigned int i; |
| |
| while ((msg = msgb_dequeue(&dl->tx_queue))) |
| msgb_free(msg); |
| for (i = 0; i < 8; i++) |
| dl->tx_length[i] = 0; |
| } |
| |
| /*! \brief 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]; |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| if (dl->rcv_buffer) |
| msgb_free(dl->rcv_buffer); |
| } |
| } |
| |
| /* \brief 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); |
| } |
| |
| static void lapdm_dl_newstate(struct lapdm_datalink *dl, uint32_t state) |
| { |
| LOGP(DLLAPDM, LOGL_INFO, "new state %s -> %s\n", |
| lapdm_state_names[dl->state], lapdm_state_names[state]); |
| |
| dl->state = state; |
| } |
| |
| static struct lapdm_datalink *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; |
| } |
| } |
| |
| /* remove the L2 header from a MSGB */ |
| static inline unsigned char *msgb_pull_l2h(struct msgb *msg) |
| { |
| unsigned char *ret = msgb_pull(msg, msg->l3h - msg->l2h); |
| msg->l2h = NULL; |
| return ret; |
| } |
| |
| /* 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(DLLAPDM, LOGL_ERROR, |
| "cannot pad message that is already too big!\n"); |
| return; |
| } |
| |
| data = msgb_put(msg, pad_len); |
| memset(data, 0x2B, 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 n201) |
| { |
| 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) = n201; |
| *msgb_push(msg, 1) = link_id; |
| *msgb_push(msg, 1) = chan_nr; |
| msgb_enqueue(&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, n201); |
| |
| return le->l1_prim_cb(&pp.oph, le->l1_ctx); |
| } |
| |
| static struct msgb *tx_dequeue_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->tx_queue))) |
| break; |
| } while (i != last); |
| |
| if (msg) { |
| /* Set last dequeue position */ |
| le->last_tx_dequeue = i; |
| } |
| |
| return msg; |
| } |
| |
| /*! \brief 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 n201; |
| |
| msg = tx_dequeue_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); |
| n201 = *msg->data; |
| msgb_pull(msg, 1); |
| |
| /* Pad the frame, we can transmit now */ |
| lapdm_pad_msgb(msg, n201); |
| |
| 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); |
| } |
| |
| /* Create RSLms various RSLms messages */ |
| static int send_rslms_rll_l3(uint8_t msg_type, struct lapdm_msg_ctx *mctx, |
| struct msgb *msg) |
| { |
| /* Add the RSL + RLL header */ |
| rsl_rll_push_l3(msg, msg_type, mctx->chan_nr, mctx->link_id, 1); |
| |
| /* 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); |
| struct abis_rsl_rll_hdr *rllh; |
| |
| /* Add the RSL + RLL header */ |
| msgb_tv16_push(msg, RSL_IE_L3_INFO, l3_len); |
| msgb_push(msg, 2 + 2); |
| rsl_rll_push_hdr(msg, RSL_MT_UNIT_DATA_IND, mctx->chan_nr, |
| mctx->link_id, 1); |
| rllh = (struct abis_rsl_rll_hdr *)msgb_l2(msg); |
| |
| rllh->data[0] = RSL_IE_TIMING_ADVANCE; |
| rllh->data[1] = mctx->ta_ind; |
| |
| rllh->data[2] = RSL_IE_MS_POWER; |
| rllh->data[3] = mctx->tx_power_ind; |
| |
| return rslms_sendmsg(msg, mctx->dl->entity); |
| } |
| |
| static int send_rll_simple(uint8_t msg_type, struct lapdm_msg_ctx *mctx) |
| { |
| struct msgb *msg; |
| |
| msg = rsl_rll_simple(msg_type, mctx->chan_nr, mctx->link_id, 1); |
| |
| /* 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; |
| |
| LOGP(DLLAPDM, LOGL_NOTICE, "sending MDL-ERROR-IND %d\n", cause); |
| msg = rsl_rll_simple(RSL_MT_ERROR_IND, mctx->chan_nr, mctx->link_id, 1); |
| msg->l2h = msgb_put(msg, sizeof(struct abis_rsl_rll_hdr)); |
| msgb_tlv_put(msg, RSL_IE_RLM_CAUSE, 1, &cause); |
| return rslms_sendmsg(msg, mctx->dl->entity); |
| } |
| |
| static int check_length_ind(struct lapdm_msg_ctx *mctx, uint8_t length_ind) |
| { |
| if (!(length_ind & 0x01)) { |
| /* 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. */ |
| LOGP(DLLAPDM, LOGL_NOTICE, |
| "we don't support multi-octet length\n"); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| static int lapdm_send_resend(struct lapdm_datalink *dl) |
| { |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm resend"); |
| int length; |
| |
| /* Resend SABM/DISC from tx_hist */ |
| length = dl->tx_length[0]; |
| msg->l2h = msgb_put(msg, length); |
| memcpy(msg->l2h, dl->tx_hist[dl->V_send], length); |
| |
| return tx_ph_data_enqueue(dl, msg, dl->mctx.chan_nr, dl->mctx.link_id, |
| dl->mctx.n201); |
| } |
| |
| static int lapdm_send_ua(struct lapdm_msg_ctx *mctx, uint8_t len, uint8_t *data) |
| { |
| uint8_t sapi = mctx->link_id & 7; |
| uint8_t f_bit = LAPDm_CTRL_PF_BIT(mctx->ctrl); |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm UA"); |
| struct lapdm_entity *le = mctx->dl->entity; |
| |
| msg->l2h = msgb_put(msg, 3 + len); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); |
| msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_UA, f_bit); |
| msg->l2h[2] = LAPDm_LEN(len); |
| if (len) |
| memcpy(msg->l2h + 3, data, len); |
| |
| return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, |
| mctx->n201); |
| } |
| |
| static int lapdm_send_dm(struct lapdm_msg_ctx *mctx) |
| { |
| uint8_t sapi = mctx->link_id & 7; |
| uint8_t f_bit = LAPDm_CTRL_PF_BIT(mctx->ctrl); |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm DM"); |
| struct lapdm_entity *le = mctx->dl->entity; |
| |
| msg->l2h = msgb_put(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); |
| msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_DM, f_bit); |
| msg->l2h[2] = 0; |
| |
| return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, |
| mctx->n201); |
| } |
| |
| static int lapdm_send_rr(struct lapdm_msg_ctx *mctx, uint8_t f_bit) |
| { |
| uint8_t sapi = mctx->link_id & 7; |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm RR"); |
| struct lapdm_entity *le = mctx->dl->entity; |
| |
| msg->l2h = msgb_put(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); |
| msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_RR, f_bit); |
| msg->l2h[2] = LAPDm_LEN(0); |
| |
| return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, |
| mctx->n201); |
| } |
| |
| static int lapdm_send_rnr(struct lapdm_msg_ctx *mctx, uint8_t f_bit) |
| { |
| uint8_t sapi = mctx->link_id & 7; |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm RNR"); |
| struct lapdm_entity *le = mctx->dl->entity; |
| |
| msg->l2h = msgb_put(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); |
| msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_RNR, f_bit); |
| msg->l2h[2] = LAPDm_LEN(0); |
| |
| return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, |
| mctx->n201); |
| } |
| |
| static int lapdm_send_rej(struct lapdm_msg_ctx *mctx, uint8_t f_bit) |
| { |
| uint8_t sapi = mctx->link_id & 7; |
| struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm REJ"); |
| struct lapdm_entity *le = mctx->dl->entity; |
| |
| msg->l2h = msgb_put(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); |
| msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_REJ, f_bit); |
| msg->l2h[2] = LAPDm_LEN(0); |
| |
| return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, |
| mctx->n201); |
| } |
| |
| /* Timer callback on T200 expiry */ |
| static void lapdm_t200_cb(void *data) |
| { |
| struct lapdm_datalink *dl = data; |
| |
| LOGP(DLLAPDM, LOGL_INFO, "lapdm_t200_cb(%p) state=%u\n", dl, dl->state); |
| |
| switch (dl->state) { |
| case LAPDm_STATE_SABM_SENT: |
| /* 5.4.1.3 */ |
| if (dl->retrans_ctr + 1 >= N200_EST_REL + 1) { |
| /* send RELEASE INDICATION to L3 */ |
| send_rll_simple(RSL_MT_REL_IND, &dl->mctx); |
| /* send MDL ERROR INIDCATION to L3 */ |
| rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); |
| /* flush tx buffers */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| /* go back to idle state */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| /* NOTE: we must not change any other states or buffers |
| * and queues, since we may reconnect after handover |
| * failure. the buffered messages is replaced there */ |
| break; |
| } |
| /* retransmit SABM command */ |
| lapdm_send_resend(dl); |
| /* increment re-transmission counter */ |
| dl->retrans_ctr++; |
| /* restart T200 (PH-READY-TO-SEND) */ |
| osmo_timer_schedule(&dl->t200, T200); |
| break; |
| case LAPDm_STATE_DISC_SENT: |
| /* 5.4.4.3 */ |
| if (dl->retrans_ctr + 1 >= N200_EST_REL + 1) { |
| /* send RELEASE INDICATION to L3 */ |
| send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); |
| /* send MDL ERROR INIDCATION to L3 */ |
| rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); |
| /* flush buffers */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| /* go back to idle state */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| /* NOTE: we must not change any other states or buffers |
| * and queues, since we may reconnect after handover |
| * failure. the buffered messages is replaced there */ |
| break; |
| } |
| /* retransmit DISC command */ |
| lapdm_send_resend(dl); |
| /* increment re-transmission counter */ |
| dl->retrans_ctr++; |
| /* restart T200 (PH-READY-TO-SEND) */ |
| osmo_timer_schedule(&dl->t200, T200); |
| break; |
| case LAPDm_STATE_MF_EST: |
| /* 5.5.7 */ |
| dl->retrans_ctr = 0; |
| lapdm_dl_newstate(dl, LAPDm_STATE_TIMER_RECOV); |
| /* fall through */ |
| case LAPDm_STATE_TIMER_RECOV: |
| dl->retrans_ctr++; |
| if (dl->retrans_ctr < N200) { |
| /* retransmit I frame (V_s-1) with P=1, if any */ |
| if (dl->tx_length[sub_mod8(dl->V_send, 1)]) { |
| struct msgb *msg; |
| int length; |
| |
| LOGP(DLLAPDM, LOGL_INFO, "retransmit last frame " |
| "V(S)=%d\n", sub_mod8(dl->V_send, 1)); |
| /* Create I frame (segment) from tx_hist */ |
| length = dl->tx_length[sub_mod8(dl->V_send, 1)]; |
| msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); |
| msg->l2h = msgb_put(msg, length); |
| memcpy(msg->l2h, |
| dl->tx_hist[sub_mod8(dl->V_send, 1)], |
| length); |
| msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, |
| sub_mod8(dl->V_send, 1), 1); /* P=1 */ |
| tx_ph_data_enqueue(dl, msg, dl->mctx.chan_nr, |
| dl->mctx.link_id, dl->mctx.n201); |
| } else { |
| /* OR send appropriate supervision frame with P=1 */ |
| if (!dl->own_busy && !dl->seq_err_cond) { |
| lapdm_send_rr(&dl->mctx, 1); |
| /* NOTE: In case of sequence error |
| * condition, the REJ frame has been |
| * transmitted when entering the |
| * condition, so it has not be done |
| * here |
| */ |
| } else if (dl->own_busy) { |
| lapdm_send_rnr(&dl->mctx, 1); |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "unhandled, " |
| "pls. fix\n"); |
| } |
| } |
| /* restart T200 (PH-READY-TO-SEND) */ |
| osmo_timer_schedule(&dl->t200, T200); |
| } else { |
| /* send MDL ERROR INIDCATION to L3 */ |
| rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); |
| } |
| break; |
| default: |
| LOGP(DLLAPDM, LOGL_INFO, "T200 expired in unexpected " |
| "dl->state %u\n", dl->state); |
| } |
| } |
| |
| /* 5.5.3.1: Common function to acknowlege frames up to the given N(R) value */ |
| static void lapdm_acknowledge(struct lapdm_msg_ctx *mctx) |
| { |
| struct lapdm_datalink *dl = mctx->dl; |
| uint8_t nr = LAPDm_CTRL_Nr(mctx->ctrl); |
| int s = 0, rej = 0, t200_reset = 0; |
| int i; |
| |
| /* supervisory frame ? */ |
| if (LAPDm_CTRL_is_S(mctx->ctrl)) |
| s = 1; |
| /* REJ frame ? */ |
| if (s && LAPDm_CTRL_S_BITS(mctx->ctrl) == LAPDm_S_REJ) |
| rej = 1; |
| |
| /* Flush all transmit buffers of acknowledged frames */ |
| for (i = dl->V_ack; i != nr; i = inc_mod8(i)) { |
| if (dl->tx_length[i]) { |
| dl->tx_length[i] = 0; |
| LOGP(DLLAPDM, LOGL_INFO, "ack frame %d\n", i); |
| } |
| } |
| |
| if (dl->state != LAPDm_STATE_TIMER_RECOV) { |
| /* When not in the timer recovery condition, the data |
| * link layer entity shall reset the timer T200 on |
| * receipt of a valid I frame with N(R) higher than V(A), |
| * or an REJ with an N(R) equal to V(A). */ |
| if ((!rej && nr != dl->V_ack) |
| || (rej && nr == dl->V_ack)) { |
| LOGP(DLLAPDM, LOGL_INFO, "reset t200\n"); |
| t200_reset = 1; |
| osmo_timer_del(&dl->t200); |
| /* 5.5.3.1 Note 1 + 2 imply timer recovery cond. */ |
| } |
| /* 5.7.4: N(R) sequence error |
| * N(R) is called valid, if and only if |
| * (N(R)-V(A)) mod 8 <= (V(S)-V(A)) mod 8. |
| */ |
| if (sub_mod8(nr, dl->V_ack) > sub_mod8(dl->V_send, dl->V_ack)) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "N(R) sequence error\n"); |
| rsl_rll_error(RLL_CAUSE_SEQ_ERR, mctx); |
| } |
| } |
| |
| /* V(A) shall be set to the value of N(R) */ |
| dl->V_ack = nr; |
| |
| /* If T200 has been reset by the receipt of an I, RR or RNR frame, |
| * and if there are outstanding I frames, restart T200 */ |
| if (t200_reset && !rej) { |
| if (dl->tx_length[dl->V_send - 1]) { |
| LOGP(DLLAPDM, LOGL_INFO, "start T200, due to unacked I " |
| "frame(s)\n"); |
| osmo_timer_schedule(&dl->t200, T200); |
| } |
| } |
| } |
| |
| /* L1 -> L2 */ |
| |
| /* Receive a LAPDm U (Unnumbered) message from L1 */ |
| static int lapdm_rx_u(struct msgb *msg, struct lapdm_msg_ctx *mctx) |
| { |
| struct lapdm_datalink *dl = mctx->dl; |
| struct lapdm_entity *le = dl->entity; |
| uint8_t length; |
| int rc; |
| int rsl_msg; |
| |
| switch (LAPDm_CTRL_U_BITS(mctx->ctrl)) { |
| case LAPDm_U_SABM: |
| rsl_msg = RSL_MT_EST_IND; |
| |
| LOGP(DLLAPDM, LOGL_INFO, "SABM received\n"); |
| /* 5.7.1 */ |
| dl->seq_err_cond = 0; |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "SABM response error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| |
| length = msg->l2h[2] >> 2; |
| /* G.4.5 If SABM is received with L>N201 or with M bit |
| * set, AN MDL-ERROR-INDICATION is sent to MM. |
| */ |
| if ((msg->l2h[2] & LAPDm_MORE) || length + 3 > mctx->n201) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "SABM too large error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); |
| return -EIO; |
| } |
| |
| /* Must be Format B */ |
| rc = check_length_ind(mctx, msg->l2h[2]); |
| if (rc < 0) { |
| msgb_free(msg); |
| return rc; |
| } |
| switch (dl->state) { |
| case LAPDm_STATE_IDLE: |
| /* Set chan_nr and link_id for established connection */ |
| memset(&dl->mctx, 0, sizeof(dl->mctx)); |
| dl->mctx.dl = dl; |
| dl->mctx.chan_nr = mctx->chan_nr; |
| dl->mctx.link_id = mctx->link_id; |
| dl->mctx.n201 = mctx->n201; |
| break; |
| case LAPDm_STATE_MF_EST: |
| if (length == 0) { |
| rsl_msg = RSL_MT_EST_CONF; |
| break; |
| } |
| LOGP(DLLAPDM, LOGL_INFO, "SABM command, multiple " |
| "frame established state\n"); |
| /* check for contention resoultion */ |
| if (dl->tx_hist[0][2] >> 2) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "SABM not allowed " |
| "during contention resolution\n"); |
| rsl_rll_error(RLL_CAUSE_SABM_INFO_NOTALL, mctx); |
| } |
| msgb_free(msg); |
| return 0; |
| case LAPDm_STATE_DISC_SENT: |
| /* 5.4.6.2 send DM with F=P */ |
| lapdm_send_dm(mctx); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| msgb_free(msg); |
| return send_rll_simple(RSL_MT_REL_CONF, mctx); |
| default: |
| lapdm_send_ua(mctx, length, msg->l2h + 3); |
| msgb_free(msg); |
| return 0; |
| } |
| /* send UA response */ |
| lapdm_send_ua(mctx, length, msg->l2h + 3); |
| /* set Vs, Vr and Va to 0 */ |
| dl->V_send = dl->V_recv = dl->V_ack = 0; |
| /* clear tx_hist */ |
| dl->tx_length[0] = 0; |
| /* enter multiple-frame-established state */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); |
| /* send notification to L3 */ |
| if (length == 0) { |
| /* 5.4.1.2 Normal establishment procedures */ |
| rc = send_rll_simple(rsl_msg, mctx); |
| msgb_free(msg); |
| } else { |
| /* 5.4.1.4 Contention resolution establishment */ |
| msg->l3h = msg->l2h + 3; |
| msgb_pull_l2h(msg); |
| rc = send_rslms_rll_l3(rsl_msg, mctx, msg); |
| } |
| break; |
| case LAPDm_U_DM: |
| LOGP(DLLAPDM, LOGL_INFO, "DM received\n"); |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "DM command error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| if (!LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| /* 5.4.1.2 DM responses with the F bit set to "0" |
| * shall be ignored. |
| */ |
| msgb_free(msg); |
| return 0; |
| } |
| switch (dl->state) { |
| case LAPDm_STATE_SABM_SENT: |
| break; |
| case LAPDm_STATE_MF_EST: |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl) == 1) { |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " |
| "response\n"); |
| rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP, mctx); |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " |
| "response, multiple frame established " |
| "state\n"); |
| rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP_MF, mctx); |
| } |
| msgb_free(msg); |
| return 0; |
| case LAPDm_STATE_TIMER_RECOV: |
| /* DM is normal in case PF = 1 */ |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl) == 0) { |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " |
| "response, multiple frame established " |
| "state\n"); |
| rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP_MF, mctx); |
| msgb_free(msg); |
| return 0; |
| } |
| break; |
| case LAPDm_STATE_DISC_SENT: |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* go to idle state */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| rc = send_rll_simple(RSL_MT_REL_CONF, mctx); |
| msgb_free(msg); |
| return 0; |
| case LAPDm_STATE_IDLE: |
| /* 5.4.5 all other frame types shall be discarded */ |
| default: |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM response! " |
| "(discarding)\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| /* reset T200 */ |
| osmo_timer_del(&dl->t200); |
| rc = send_rll_simple(RSL_MT_REL_IND, mctx); |
| msgb_free(msg); |
| break; |
| case LAPDm_U_UI: |
| LOGP(DLLAPDM, LOGL_INFO, "UI received\n"); |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "UI indicates response " |
| "error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| |
| length = msg->l2h[2] >> 2; |
| /* FIXME: G.4.5 If UI is received with L>N201 or with M bit |
| * set, AN MDL-ERROR-INDICATION is sent to MM. |
| */ |
| |
| if (mctx->lapdm_fmt == LAPDm_FMT_B4) { |
| length = N201_B4; |
| msg->l3h = msg->l2h + 2; |
| } else { |
| rc = check_length_ind(mctx, msg->l2h[2]); |
| if (rc < 0) { |
| msgb_free(msg); |
| return rc; |
| } |
| length = msg->l2h[2] >> 2; |
| msg->l3h = msg->l2h + 3; |
| } |
| /* do some length checks */ |
| if (length == 0) { |
| /* 5.3.3 UI frames received with the length indicator |
| * set to "0" shall be ignored |
| */ |
| LOGP(DLLAPDM, LOGL_INFO, "length=0 (discarding)\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| switch (LAPDm_ADDR_SAPI(mctx->addr)) { |
| case LAPDm_SAPI_NORMAL: |
| case LAPDm_SAPI_SMS: |
| break; |
| default: |
| /* 5.3.3 UI frames with invalid SAPI values shall be |
| * discarded |
| */ |
| LOGP(DLLAPDM, LOGL_INFO, "sapi=%u (discarding)\n", |
| LAPDm_ADDR_SAPI(mctx->addr)); |
| msgb_free(msg); |
| return 0; |
| } |
| msgb_pull_l2h(msg); |
| rc = send_rslms_rll_l3_ui(mctx, msg); |
| break; |
| case LAPDm_U_DISC: |
| rsl_msg = RSL_MT_REL_IND; |
| |
| LOGP(DLLAPDM, LOGL_INFO, "DISC received\n"); |
| /* flush buffers */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| /* 5.7.1 */ |
| dl->seq_err_cond = 0; |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "DISC response error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| length = msg->l2h[2] >> 2; |
| if (length > 0 || msg->l2h[2] & 0x02) { |
| /* G.4.4 If a DISC or DM frame is received with L>0 or |
| * with the M bit set to "1", an MDL-ERROR-INDICATION |
| * primitive with cause "U frame with incorrect |
| * parameters" is sent to the mobile management entity. |
| */ |
| LOGP(DLLAPDM, LOGL_NOTICE, |
| "U frame iwth incorrect parameters "); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); |
| return -EIO; |
| } |
| switch (dl->state) { |
| case LAPDm_STATE_IDLE: |
| LOGP(DLLAPDM, LOGL_INFO, "DISC in idle state\n"); |
| /* send DM with F=P */ |
| msgb_free(msg); |
| return lapdm_send_dm(mctx); |
| case LAPDm_STATE_SABM_SENT: |
| LOGP(DLLAPDM, LOGL_INFO, "DISC in SABM state\n"); |
| /* 5.4.6.2 send DM with F=P */ |
| lapdm_send_dm(mctx); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| msgb_free(msg); |
| return send_rll_simple(RSL_MT_REL_IND, mctx); |
| case LAPDm_STATE_MF_EST: |
| case LAPDm_STATE_TIMER_RECOV: |
| LOGP(DLLAPDM, LOGL_INFO, "DISC in est state\n"); |
| break; |
| case LAPDm_STATE_DISC_SENT: |
| LOGP(DLLAPDM, LOGL_INFO, "DISC in disc state\n"); |
| rsl_msg = RSL_MT_REL_CONF; |
| break; |
| default: |
| lapdm_send_ua(mctx, length, msg->l2h + 3); |
| msgb_free(msg); |
| return 0; |
| } |
| /* send UA response */ |
| lapdm_send_ua(mctx, length, msg->l2h + 3); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* enter idle state */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| /* send notification to L3 */ |
| rc = send_rll_simple(rsl_msg, mctx); |
| msgb_free(msg); |
| break; |
| case LAPDm_U_UA: |
| LOGP(DLLAPDM, LOGL_INFO, "UA received\n"); |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "UA indicates command " |
| "error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| |
| length = msg->l2h[2] >> 2; |
| /* G.4.5 If UA is received with L>N201 or with M bit |
| * set, AN MDL-ERROR-INDICATION is sent to MM. |
| */ |
| if ((msg->l2h[2] & LAPDm_MORE) || length + 3 > mctx->n201) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "UA too large error\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); |
| return -EIO; |
| } |
| |
| if (!LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| /* 5.4.1.2 A UA response with the F bit set to "0" |
| * shall be ignored. |
| */ |
| LOGP(DLLAPDM, LOGL_INFO, "F=0 (discarding)\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| switch (dl->state) { |
| case LAPDm_STATE_SABM_SENT: |
| break; |
| case LAPDm_STATE_MF_EST: |
| case LAPDm_STATE_TIMER_RECOV: |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited UA response! " |
| "(discarding)\n"); |
| rsl_rll_error(RLL_CAUSE_UNSOL_UA_RESP, mctx); |
| msgb_free(msg); |
| return 0; |
| case LAPDm_STATE_DISC_SENT: |
| LOGP(DLLAPDM, LOGL_INFO, "UA in disconnect state\n"); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* go to idle state */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| rc = send_rll_simple(RSL_MT_REL_CONF, mctx); |
| msgb_free(msg); |
| return 0; |
| case LAPDm_STATE_IDLE: |
| /* 5.4.5 all other frame types shall be discarded */ |
| default: |
| LOGP(DLLAPDM, LOGL_INFO, "unsolicited UA response! " |
| "(discarding)\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| LOGP(DLLAPDM, LOGL_INFO, "UA in SABM state\n"); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* compare UA with SABME if contention resolution is applied */ |
| if (dl->tx_hist[0][2] >> 2) { |
| rc = check_length_ind(mctx, msg->l2h[2]); |
| if (rc < 0) { |
| rc = send_rll_simple(RSL_MT_REL_IND, mctx); |
| msgb_free(msg); |
| /* go to idle state */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| return 0; |
| } |
| length = msg->l2h[2] >> 2; |
| if (length != (dl->tx_hist[0][2] >> 2) |
| || !!memcmp(dl->tx_hist[0] + 3, msg->l2h + 3, |
| length)) { |
| LOGP(DLLAPDM, LOGL_INFO, "**** UA response " |
| "mismatches ****\n"); |
| rc = send_rll_simple(RSL_MT_REL_IND, mctx); |
| msgb_free(msg); |
| /* go to idle state */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| return 0; |
| } |
| } |
| /* set Vs, Vr and Va to 0 */ |
| dl->V_send = dl->V_recv = dl->V_ack = 0; |
| /* clear tx_hist */ |
| dl->tx_length[0] = 0; |
| /* enter multiple-frame-established state */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); |
| /* send outstanding frames, if any (resume / reconnect) */ |
| rslms_send_i(mctx, __LINE__); |
| /* send notification to L3 */ |
| rc = send_rll_simple(RSL_MT_EST_CONF, mctx); |
| msgb_free(msg); |
| break; |
| default: |
| /* G.3.1 */ |
| LOGP(DLLAPDM, LOGL_NOTICE, "Unnumbered frame not allowed.\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| return rc; |
| } |
| |
| /* Receive a LAPDm S (Supervisory) message from L1 */ |
| static int lapdm_rx_s(struct msgb *msg, struct lapdm_msg_ctx *mctx) |
| { |
| struct lapdm_datalink *dl = mctx->dl; |
| struct lapdm_entity *le = dl->entity; |
| uint8_t length; |
| |
| length = msg->l2h[2] >> 2; |
| if (length > 0 || msg->l2h[2] & 0x02) { |
| /* G.4.3 If a supervisory frame is received with L>0 or |
| * with the M bit set to "1", an MDL-ERROR-INDICATION |
| * primitive with cause "S frame with incorrect |
| * parameters" is sent to the mobile management entity. */ |
| LOGP(DLLAPDM, LOGL_NOTICE, |
| "S frame with incorrect parameters\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_SFRM_INC_PARAM, mctx); |
| return -EIO; |
| } |
| |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl) |
| && dl->state != LAPDm_STATE_TIMER_RECOV) { |
| /* 5.4.2.2: Inidcate error on supervisory reponse F=1 */ |
| LOGP(DLLAPDM, LOGL_NOTICE, "S frame response with F=1 error\n"); |
| rsl_rll_error(RLL_CAUSE_UNSOL_SPRV_RESP, mctx); |
| } |
| |
| switch (dl->state) { |
| case LAPDm_STATE_IDLE: |
| /* if P=1, respond DM with F=1 (5.2.2) */ |
| /* 5.4.5 all other frame types shall be discarded */ |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) |
| lapdm_send_dm(mctx); /* F=P */ |
| /* fall though */ |
| case LAPDm_STATE_SABM_SENT: |
| case LAPDm_STATE_DISC_SENT: |
| LOGP(DLLAPDM, LOGL_NOTICE, "S frame ignored in this state\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| switch (LAPDm_CTRL_S_BITS(mctx->ctrl)) { |
| case LAPDm_S_RR: |
| LOGP(DLLAPDM, LOGL_INFO, "RR received\n"); |
| /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ |
| lapdm_acknowledge(mctx); |
| |
| /* 5.5.3.2 */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| if (!dl->own_busy && !dl->seq_err_cond) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "RR frame command " |
| "with polling bit set and we are not " |
| "busy, so we reply with RR frame\n"); |
| lapdm_send_rr(mctx, 1); |
| /* NOTE: In case of sequence error condition, |
| * the REJ frame has been transmitted when |
| * entering the condition, so it has not be |
| * done here |
| */ |
| } else if (dl->own_busy) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "RR frame command " |
| "with polling bit set and we are busy, " |
| "so we reply with RR frame\n"); |
| lapdm_send_rnr(mctx, 1); |
| } |
| } else if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl) |
| && dl->state == LAPDm_STATE_TIMER_RECOV) { |
| LOGP(DLLAPDM, LOGL_INFO, "RR response with F==1, " |
| "and we are in timer recovery state, so " |
| "we leave that state\n"); |
| /* V(S) to the N(R) in the RR frame */ |
| dl->V_send = LAPDm_CTRL_Nr(mctx->ctrl); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* 5.5.7 Clear timer recovery condition */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); |
| } |
| /* Send message, if possible due to acknowledged data */ |
| rslms_send_i(mctx, __LINE__); |
| |
| break; |
| case LAPDm_S_RNR: |
| LOGP(DLLAPDM, LOGL_INFO, "RNR received\n"); |
| /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ |
| lapdm_acknowledge(mctx); |
| |
| /* 5.5.5 */ |
| /* Set peer receiver busy condition */ |
| dl->peer_busy = 1; |
| |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { |
| if (!dl->own_busy) { |
| LOGP(DLLAPDM, LOGL_INFO, "RNR poll " |
| "command and we are not busy, " |
| "so we reply with RR final " |
| "response\n"); |
| /* Send RR with F=1 */ |
| lapdm_send_rr(mctx, 1); |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "RNR poll " |
| "command and we are busy, so " |
| "we reply with RNR final " |
| "response\n"); |
| /* Send RNR with F=1 */ |
| lapdm_send_rnr(mctx, 1); |
| } |
| } else if (dl->state == LAPDm_STATE_TIMER_RECOV) { |
| LOGP(DLLAPDM, LOGL_INFO, "RNR poll response " |
| "and we in timer recovery state, so " |
| "we leave that state\n"); |
| /* 5.5.7 Clear timer recovery condition */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); |
| /* V(S) to the N(R) in the RNR frame */ |
| dl->V_send = LAPDm_CTRL_Nr(mctx->ctrl); |
| } |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "RNR not polling/final state " |
| "received\n"); |
| |
| /* Send message, if possible due to acknowledged data */ |
| rslms_send_i(mctx, __LINE__); |
| |
| break; |
| case LAPDm_S_REJ: |
| LOGP(DLLAPDM, LOGL_INFO, "REJ received\n"); |
| /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ |
| lapdm_acknowledge(mctx); |
| |
| /* 5.5.4.1 */ |
| if (dl->state != LAPDm_STATE_TIMER_RECOV) { |
| /* Clear an existing peer receiver busy condition */ |
| dl->peer_busy = 0; |
| /* V(S) and V(A) to the N(R) in the REJ frame */ |
| dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* 5.5.3.2 */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| if (!dl->own_busy && !dl->seq_err_cond) { |
| LOGP(DLLAPDM, LOGL_INFO, "REJ poll " |
| "command not in timer recovery " |
| "state and not in own busy " |
| "condition received, so we " |
| "respond with RR final " |
| "response\n"); |
| lapdm_send_rr(mctx, 1); |
| /* NOTE: In case of sequence error |
| * condition, the REJ frame has been |
| * transmitted when entering the |
| * condition, so it has not be done |
| * here |
| */ |
| } else if (dl->own_busy) { |
| LOGP(DLLAPDM, LOGL_INFO, "REJ poll " |
| "command not in timer recovery " |
| "state and in own busy " |
| "condition received, so we " |
| "respond with RNR final " |
| "response\n"); |
| lapdm_send_rnr(mctx, 1); |
| } |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "REJ response or not " |
| "polling command not in timer recovery " |
| "state received\n"); |
| /* send MDL ERROR INIDCATION to L3 */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| rsl_rll_error(RLL_CAUSE_UNSOL_SPRV_RESP, mctx); |
| } |
| |
| } else if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| LOGP(DLLAPDM, LOGL_INFO, "REJ poll response in timer " |
| "recovery state received\n"); |
| /* Clear an existing peer receiver busy condition */ |
| dl->peer_busy = 0; |
| /* 5.5.7 Clear timer recovery condition */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); |
| /* V(S) and V(A) to the N(R) in the REJ frame */ |
| dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| } else { |
| /* Clear an existing peer receiver busy condition */ |
| dl->peer_busy = 0; |
| /* V(S) and V(A) to the N(R) in the REJ frame */ |
| dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); |
| /* 5.5.3.2 */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd |
| && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| if (!dl->own_busy && !dl->seq_err_cond) { |
| LOGP(DLLAPDM, LOGL_INFO, "REJ poll " |
| "command in timer recovery " |
| "state and not in own busy " |
| "condition received, so we " |
| "respond with RR final " |
| "response\n"); |
| lapdm_send_rr(mctx, 1); |
| /* NOTE: In case of sequence error |
| * condition, the REJ frame has been |
| * transmitted when entering the |
| * condition, so it has not be done |
| * here |
| */ |
| } else if (dl->own_busy) { |
| LOGP(DLLAPDM, LOGL_INFO, "REJ poll " |
| "command in timer recovery " |
| "state and in own busy " |
| "condition received, so we " |
| "respond with RNR final " |
| "response\n"); |
| lapdm_send_rnr(mctx, 1); |
| } |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "REJ response or not " |
| "polling command in timer recovery " |
| "state received\n"); |
| } |
| |
| /* FIXME: 5.5.4.2 2) */ |
| |
| /* Send message, if possible due to acknowledged data */ |
| rslms_send_i(mctx, __LINE__); |
| |
| break; |
| default: |
| /* G.3.1 */ |
| LOGP(DLLAPDM, LOGL_NOTICE, "Supervisory frame not allowed.\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| msgb_free(msg); |
| return 0; |
| } |
| |
| /* Receive a LAPDm I (Information) message from L1 */ |
| static int lapdm_rx_i(struct msgb *msg, struct lapdm_msg_ctx *mctx) |
| { |
| struct lapdm_datalink *dl = mctx->dl; |
| struct lapdm_entity *le = dl->entity; |
| //uint8_t nr = LAPDm_CTRL_Nr(mctx->ctrl); |
| uint8_t ns = LAPDm_CTRL_I_Ns(mctx->ctrl); |
| uint8_t length; |
| int rc; |
| |
| LOGP(DLLAPDM, LOGL_NOTICE, "I received\n"); |
| |
| /* G.2.2 Wrong value of the C/R bit */ |
| if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "I frame response not allowed\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| |
| length = msg->l2h[2] >> 2; |
| if (length == 0 || length + 3 > mctx->n201) { |
| /* G.4.2 If the length indicator of an I frame is set |
| * to a numerical value L>N201 or L=0, an MDL-ERROR-INDICATION |
| * primitive with cause "I frame with incorrect length" |
| * is sent to the mobile management entity. */ |
| LOGP(DLLAPDM, LOGL_NOTICE, "I frame length not allowed\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_IFRM_INC_LEN, mctx); |
| return -EIO; |
| } |
| |
| /* G.4.2 If the numerical value of L is L<N201 and the M |
| * bit is set to "1", then an MDL-ERROR-INDICATION primitive with |
| * cause "I frame with incorrect use of M bit" is sent to the |
| * mobile management entity. */ |
| if ((msg->l2h[2] & LAPDm_MORE) && length + 3 < mctx->n201) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "I frame with M bit too short\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_IFRM_INC_MBITS, mctx); |
| return -EIO; |
| } |
| |
| switch (dl->state) { |
| case LAPDm_STATE_IDLE: |
| /* if P=1, respond DM with F=1 (5.2.2) */ |
| /* 5.4.5 all other frame types shall be discarded */ |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) |
| lapdm_send_dm(mctx); /* F=P */ |
| /* fall though */ |
| case LAPDm_STATE_SABM_SENT: |
| case LAPDm_STATE_DISC_SENT: |
| LOGP(DLLAPDM, LOGL_NOTICE, "I frame ignored in this state\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| |
| /* 5.7.1: N(s) sequence error */ |
| if (ns != dl->V_recv) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "N(S) sequence error: N(S)=%u, " |
| "V(R)=%u\n", ns, dl->V_recv); |
| /* discard data */ |
| msgb_free(msg); |
| if (!dl->seq_err_cond) { |
| /* FIXME: help me understand what exactly todo here |
| dl->seq_err_cond = 1; |
| */ |
| lapdm_send_rej(mctx, LAPDm_CTRL_PF_BIT(mctx->ctrl)); |
| } else { |
| } |
| return -EIO; |
| } |
| dl->seq_err_cond = 0; |
| |
| /* Increment receiver state */ |
| dl->V_recv = inc_mod8(dl->V_recv); |
| LOGP(DLLAPDM, LOGL_NOTICE, "incrementing V(R) to %u\n", dl->V_recv); |
| |
| /* 5.5.3.1: Acknowlege all transmitted frames up the the N(R)-1 */ |
| lapdm_acknowledge(mctx); /* V(A) is also set here */ |
| |
| /* Only if we are not in own receiver busy condition */ |
| if (!dl->own_busy) { |
| /* if the frame carries a complete segment */ |
| if (!(msg->l2h[2] & LAPDm_MORE) |
| && !dl->rcv_buffer) { |
| LOGP(DLLAPDM, LOGL_INFO, "message in single I frame\n"); |
| /* send a DATA INDICATION to L3 */ |
| msg->l3h = msg->l2h + 3; |
| msgb_pull_l2h(msg); |
| msg->len = length; |
| msg->tail = msg->data + length; |
| rc = send_rslms_rll_l3(RSL_MT_DATA_IND, mctx, msg); |
| } else { |
| /* create rcv_buffer */ |
| if (!dl->rcv_buffer) { |
| LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " |
| "frames (first message)\n"); |
| dl->rcv_buffer = msgb_alloc_headroom(200+56, 56, |
| "LAPDm RX"); |
| dl->rcv_buffer->l3h = dl->rcv_buffer->data; |
| } |
| /* concat. rcv_buffer */ |
| if (msgb_l3len(dl->rcv_buffer) + length > 200) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "Received frame " |
| "overflow!\n"); |
| } else { |
| memcpy(msgb_put(dl->rcv_buffer, length), |
| msg->l2h + 3, length); |
| } |
| /* if the last segment was received */ |
| if (!(msg->l2h[2] & LAPDm_MORE)) { |
| LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " |
| "frames (last message)\n"); |
| rc = send_rslms_rll_l3(RSL_MT_DATA_IND, mctx, |
| dl->rcv_buffer); |
| dl->rcv_buffer = NULL; |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " |
| "frames (next message)\n"); |
| msgb_free(msg); |
| |
| } |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "I frame ignored during own receiver " |
| "busy condition\n"); |
| |
| /* Check for P bit */ |
| if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) { |
| /* 5.5.2.1 */ |
| /* check if we are not in own receiver busy */ |
| if (!dl->own_busy) { |
| LOGP(DLLAPDM, LOGL_INFO, "we are not busy, send RR\n"); |
| /* Send RR with F=1 */ |
| rc = lapdm_send_rr(mctx, 1); |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "we are busy, send RNR\n"); |
| /* Send RNR with F=1 */ |
| rc = lapdm_send_rnr(mctx, 1); |
| } |
| } else { |
| /* 5.5.2.2 */ |
| /* check if we are not in own receiver busy */ |
| if (!dl->own_busy) { |
| /* NOTE: V(R) is already set above */ |
| rc = rslms_send_i(mctx, __LINE__); |
| if (rc) { |
| LOGP(DLLAPDM, LOGL_INFO, "we are not busy and " |
| "have no pending data, send RR\n"); |
| /* Send RR with F=0 */ |
| return lapdm_send_rr(mctx, 0); |
| } |
| /* all I or one RR is sent, we are done */ |
| return 0; |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "we are busy, send RNR\n"); |
| /* Send RNR with F=0 */ |
| rc = lapdm_send_rnr(mctx, 0); |
| } |
| } |
| |
| /* Send message, if possible due to acknowledged data */ |
| rslms_send_i(mctx, __LINE__); |
| |
| return rc; |
| } |
| |
| /* Receive a LAPDm message from L1 */ |
| static int lapdm_ph_data_ind(struct msgb *msg, struct lapdm_msg_ctx *mctx) |
| { |
| int rc; |
| |
| /* G.2.3 EA bit set to "0" is not allowed in GSM */ |
| if (!LAPDm_ADDR_EA(mctx->addr)) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "EA bit 0 is not allowed in GSM\n"); |
| msgb_free(msg); |
| rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); |
| return -EINVAL; |
| } |
| |
| if (LAPDm_CTRL_is_U(mctx->ctrl)) |
| rc = lapdm_rx_u(msg, mctx); |
| else if (LAPDm_CTRL_is_S(mctx->ctrl)) |
| rc = lapdm_rx_s(msg, mctx); |
| else if (LAPDm_CTRL_is_I(mctx->ctrl)) |
| rc = lapdm_rx_i(msg, mctx); |
| else { |
| LOGP(DLLAPDM, LOGL_NOTICE, "unknown LAPDm format\n"); |
| msgb_free(msg); |
| rc = -EINVAL; |
| } |
| return rc; |
| } |
| |
| /* 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; |
| int rc = 0; |
| |
| /* when we reach here, we have a msgb with l2h pointing to the raw |
| * 23byte mac block. The l1h has already been purged. */ |
| |
| mctx.chan_nr = chan_nr; |
| mctx.link_id = link_id; |
| mctx.addr = mctx.ctrl = 0; |
| |
| /* 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; |
| mctx.n201 = N201_Bbis; |
| sapi = 0; |
| } else { |
| if (mctx.link_id & 0x40) { |
| /* It was received from network on SACCH */ |
| |
| /* If sent by BTS, lapdm_fmt must be B4 */ |
| if (le->mode == LAPDM_MODE_MS) { |
| mctx.lapdm_fmt = LAPDm_FMT_B4; |
| mctx.n201 = N201_B4; |
| LOGP(DLLAPDM, LOGL_INFO, "fmt=B4\n"); |
| } else { |
| mctx.lapdm_fmt = LAPDm_FMT_B; |
| mctx.n201 = N201_AB_SACCH; |
| LOGP(DLLAPDM, LOGL_INFO, "fmt=B\n"); |
| } |
| /* 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; |
| LOGP(DLLAPDM, LOGL_INFO, "fmt=B\n"); |
| mctx.n201 = 23; // FIXME: select correct size by chan. |
| sapi = (msg->l2h[0] >> 2) & 7; |
| } |
| } |
| |
| mctx.dl = datalink_for_sapi(le, sapi); |
| /* G.2.1 No action on frames containing an unallocated SAPI. */ |
| if (!mctx.dl) { |
| LOGP(DLLAPDM, 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: |
| mctx.addr = msg->l2h[0]; |
| if (!(mctx.addr & 0x01)) { |
| LOGP(DLLAPDM, LOGL_ERROR, "we don't support " |
| "multibyte addresses (discarding)\n"); |
| msgb_free(msg); |
| return -EINVAL; |
| } |
| mctx.ctrl = msg->l2h[1]; |
| /* obtain SAPI from address field */ |
| mctx.link_id |= LAPDm_ADDR_SAPI(mctx.addr); |
| rc = lapdm_ph_data_ind(msg, &mctx); |
| break; |
| case LAPDm_FMT_Bter: |
| /* FIXME */ |
| msgb_free(msg); |
| break; |
| case LAPDm_FMT_Bbis: |
| /* directly pass up to layer3 */ |
| LOGP(DLLAPDM, LOGL_INFO, "fmt=Bbis UI\n"); |
| msg->l3h = msg->l2h; |
| msgb_pull_l2h(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"); |
| |
| 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); |
| |
| /*! \brief 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(DLLAPDM, LOGL_ERROR, "primitive for unknown SAP %u\n", |
| oph->sap); |
| return -ENODEV; |
| } |
| |
| switch (oph->primitive) { |
| case PRIM_PH_DATA: |
| if (oph->operation != PRIM_OP_INDICATION) { |
| LOGP(DLLAPDM, LOGL_ERROR, "PH_DATA is not INDICATION %u\n", |
| oph->operation); |
| return -ENODEV; |
| } |
| 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(DLLAPDM, LOGL_ERROR, "PH_RTS is not INDICATION %u\n", |
| oph->operation); |
| return -ENODEV; |
| } |
| 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: |
| return -EIO; |
| } |
| break; |
| } |
| |
| return rc; |
| } |
| |
| |
| /* L3 -> L2 / RSLMS -> LAPDm */ |
| |
| /* L3 requests establishment of data link */ |
| static int rslms_rx_rll_est_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 = rllh->link_id & 7; |
| struct tlv_parsed tv; |
| uint8_t length; |
| uint8_t n201 = 23; //FIXME |
| |
| /* Set chan_nr and link_id for established connection */ |
| memset(&dl->mctx, 0, sizeof(dl->mctx)); |
| dl->mctx.dl = dl; |
| dl->mctx.n201 = n201; |
| dl->mctx.chan_nr = chan_nr; |
| dl->mctx.link_id = link_id; |
| |
| rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); |
| if (TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { |
| msg->l3h = 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 */ |
| LOGP(DLLAPDM, 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); |
| LOGP(DLLAPDM, LOGL_INFO, "perform establishment with content " |
| "(SABM)\n"); |
| } else { |
| /* normal establishment procedure */ |
| length = 0; |
| LOGP(DLLAPDM, LOGL_INFO, "perform normal establishm. (SABM)\n"); |
| } |
| |
| /* check if the layer3 message length exceeds N201 */ |
| if (length + 3 > 21) { /* FIXME: do we know the channel N201? */ |
| LOGP(DLLAPDM, LOGL_ERROR, "frame too large: %d > N201(%d) " |
| "(discarding)\n", length + 3, 21); |
| msgb_free(msg); |
| return send_rll_simple(RSL_MT_REL_IND, &dl->mctx); |
| } |
| |
| /* Flush send-queue */ |
| /* Clear send-buffer */ |
| lapdm_dl_flush_send(dl); |
| |
| /* Discard partly received L3 message */ |
| if (dl->rcv_buffer) { |
| msgb_free(dl->rcv_buffer); |
| dl->rcv_buffer = NULL; |
| } |
| |
| /* Remove RLL header from msgb */ |
| msgb_pull_l2h(msg); |
| |
| /* Push LAPDm header on msgb */ |
| msg->l2h = msgb_push(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); |
| msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_SABM, 1); |
| msg->l2h[2] = LAPDm_LEN(length); |
| /* Transmit-buffer carries exactly one segment */ |
| memcpy(dl->tx_hist[0], msg->l2h, 3 + length); |
| dl->tx_length[0] = 3 + length; |
| /* set Vs to 0, because it is used as index when resending SABM */ |
| dl->V_send = 0; |
| |
| /* Set states */ |
| dl->own_busy = dl->peer_busy = 0; |
| dl->retrans_ctr = 0; |
| lapdm_dl_newstate(dl, LAPDm_STATE_SABM_SENT); |
| |
| /* Tramsmit and start T200 */ |
| osmo_timer_schedule(&dl->t200, T200); |
| return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); |
| } |
| |
| /* 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; |
| uint8_t n201 = 23; //FIXME |
| uint8_t ta = 0, tx_power = 0; |
| |
| /* 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)) { |
| ta = *TLVP_VAL(&tv, RSL_IE_TIMING_ADVANCE); |
| } |
| if (TLVP_PRESENT(&tv, RSL_IE_MS_POWER)) { |
| tx_power = *TLVP_VAL(&tv, RSL_IE_MS_POWER); |
| } |
| if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { |
| LOGP(DLLAPDM, LOGL_ERROR, "unit data request without message " |
| "error\n"); |
| msgb_free(msg); |
| return -EINVAL; |
| } |
| msg->l3h = 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 + 5 > 23) { /* FIXME: do we know the channel N201? */ |
| LOGP(DLLAPDM, LOGL_ERROR, "frame too large: %d > N201(%d) " |
| "(discarding)\n", length + 5, 23); |
| msgb_free(msg); |
| return -EIO; |
| } |
| |
| LOGP(DLLAPDM, LOGL_INFO, "sending unit data (tx_power=%d, ta=%d)\n", |
| tx_power, ta); |
| |
| /* Remove RLL header from msgb */ |
| msgb_pull_l2h(msg); |
| |
| /* Push L1 + LAPDm header on msgb */ |
| msg->l2h = msgb_push(msg, 2 + 3); |
| msg->l2h[0] = tx_power; |
| msg->l2h[1] = ta; |
| msg->l2h[2] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); |
| msg->l2h[3] = LAPDm_CTRL_U(LAPDm_U_UI, 0); |
| msg->l2h[4] = LAPDm_LEN(length); |
| // FIXME: short L2 header support |
| |
| /* Tramsmit */ |
| return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); |
| } |
| |
| /* 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; |
| |
| rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); |
| if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { |
| LOGP(DLLAPDM, LOGL_ERROR, "data request without message " |
| "error\n"); |
| msgb_free(msg); |
| return -EINVAL; |
| } |
| msg->l3h = TLVP_VAL(&tv, RSL_IE_L3_INFO); |
| |
| LOGP(DLLAPDM, LOGL_INFO, "writing message to send-queue\n"); |
| |
| /* Remove the RSL/RLL header */ |
| msgb_pull_l2h(msg); |
| |
| /* Write data into the send queue */ |
| msgb_enqueue(&dl->send_queue, msg); |
| |
| /* Send message, if possible */ |
| rslms_send_i(&dl->mctx, __LINE__); |
| return 0; |
| } |
| |
| /* Send next I frame from queued/buffered data */ |
| static int rslms_send_i(struct lapdm_msg_ctx *mctx, int line) |
| { |
| struct lapdm_datalink *dl = mctx->dl; |
| struct lapdm_entity *le = dl->entity; |
| uint8_t chan_nr = mctx->chan_nr; |
| uint8_t link_id = mctx->link_id; |
| uint8_t sapi = link_id & 7; |
| int k = k_sapi[sapi]; |
| struct msgb *msg; |
| int length, left; |
| int rc = - 1; /* we sent nothing */ |
| |
| LOGP(DLLAPDM, LOGL_INFO, "%s() called from line %d\n", __func__, line); |
| |
| next_frame: |
| |
| if (dl->peer_busy) { |
| LOGP(DLLAPDM, LOGL_INFO, "peer busy, not sending\n"); |
| return rc; |
| } |
| |
| if (dl->state == LAPDm_STATE_TIMER_RECOV) { |
| LOGP(DLLAPDM, LOGL_INFO, "timer recovery, not sending\n"); |
| return rc; |
| } |
| |
| /* If the send state variable V(S) is equal to V(A) plus k |
| * (where k is the maximum number of outstanding I frames - see |
| * subclause 5.8.4), the data link layer entity shall not transmit any |
| * new I frames, but shall retransmit an I frame as a result |
| * of the error recovery procedures as described in subclauses 5.5.4 and |
| * 5.5.7. */ |
| if (dl->V_send == add_mod8(dl->V_ack, k)) { |
| LOGP(DLLAPDM, LOGL_INFO, "k frames outstanding, not sending " |
| "more (k=%u V(S)=%u V(A)=%u)\n", k, dl->V_send, |
| dl->V_ack); |
| return rc; |
| } |
| |
| /* if we have no tx_hist yet, we create it */ |
| if (!dl->tx_length[dl->V_send]) { |
| /* Get next message into send-buffer, if any */ |
| if (!dl->send_buffer) { |
| next_message: |
| dl->send_out = 0; |
| dl->send_buffer = msgb_dequeue(&dl->send_queue); |
| /* No more data to be sent */ |
| if (!dl->send_buffer) |
| return rc; |
| LOGP(DLLAPDM, LOGL_INFO, "get message from " |
| "send-queue\n"); |
| } |
| |
| /* How much is left in the send-buffer? */ |
| left = msgb_l3len(dl->send_buffer) - dl->send_out; |
| /* Segment, if data exceeds N201 */ |
| length = left; |
| if (length > mctx->n201 - 3) |
| length = mctx->n201 - 3; |
| LOGP(DLLAPDM, LOGL_INFO, "msg-len %d sent %d left %d N201 %d " |
| "length %d first byte %02x\n", |
| msgb_l3len(dl->send_buffer), dl->send_out, left, |
| mctx->n201, length, dl->send_buffer->l3h[0]); |
| /* If message in send-buffer is completely sent */ |
| if (left == 0) { |
| msgb_free(dl->send_buffer); |
| dl->send_buffer = NULL; |
| goto next_message; |
| } |
| |
| LOGP(DLLAPDM, LOGL_INFO, "send I frame %sV(S)=%d\n", |
| (left > length) ? "segment " : "", dl->V_send); |
| |
| /* Create I frame (segment) and transmit-buffer content */ |
| msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); |
| msg->l2h = msgb_put(msg, 3 + length); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); |
| msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, dl->V_send, 0); |
| msg->l2h[2] = LAPDm_LEN(length); |
| if (left > length) |
| msg->l2h[2] |= LAPDm_MORE; |
| memcpy(msg->l2h + 3, dl->send_buffer->l3h + dl->send_out, |
| length); |
| memcpy(dl->tx_hist[dl->V_send], msg->l2h, 3 + length); |
| dl->tx_length[dl->V_send] = 3 + length; |
| /* Add length to track how much is already in the tx buffer */ |
| dl->send_out += length; |
| } else { |
| LOGP(DLLAPDM, LOGL_INFO, "resend I frame from tx buffer " |
| "V(S)=%d\n", dl->V_send); |
| |
| /* Create I frame (segment) from tx_hist */ |
| length = dl->tx_length[dl->V_send]; |
| msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); |
| msg->l2h = msgb_put(msg, length); |
| memcpy(msg->l2h, dl->tx_hist[dl->V_send], length); |
| msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, dl->V_send, 0); |
| } |
| |
| /* The value of the send state variable V(S) shall be incremented by 1 |
| * at the end of the transmission of the I frame */ |
| dl->V_send = inc_mod8(dl->V_send); |
| |
| /* If timer T200 is not running at the time right before transmitting a |
| * frame, when the PH-READY-TO-SEND primitive is received from the |
| * physical layer., it shall be set. */ |
| if (!osmo_timer_pending(&dl->t200)) |
| osmo_timer_schedule(&dl->t200, T200); |
| |
| tx_ph_data_enqueue(dl, msg, chan_nr, link_id, mctx->n201); |
| |
| rc = 0; /* we sent something */ |
| goto next_frame; |
| } |
| |
| /* 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; |
| |
| if (sapi != 0) { |
| LOGP(DLLAPDM, LOGL_ERROR, "SAPI != 0 while suspending\n"); |
| msgb_free(msg); |
| return -EINVAL; |
| } |
| |
| LOGP(DLLAPDM, LOGL_INFO, "perform suspension\n"); |
| |
| /* put back the send-buffer to the send-queue (first position) */ |
| if (dl->send_buffer) { |
| LOGP(DLLAPDM, LOGL_INFO, "put frame in sendbuffer back to " |
| "queue\n"); |
| llist_add(&dl->send_buffer->list, &dl->send_queue); |
| dl->send_buffer = NULL; |
| } else |
| LOGP(DLLAPDM, LOGL_INFO, "no frame in sendbuffer\n"); |
| |
| /* Clear transmit buffer, but keep send buffer */ |
| lapdm_dl_flush_tx(dl); |
| |
| msgb_free(msg); |
| |
| return send_rll_simple(RSL_MT_SUSP_CONF, &dl->mctx); |
| } |
| |
| /* L3 requests resume of data link */ |
| static int rslms_rx_rll_res_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 = rllh->link_id & 7; |
| struct tlv_parsed tv; |
| uint8_t length; |
| uint8_t n201 = 23; //FIXME |
| |
| /* Set chan_nr and link_id for established connection */ |
| memset(&dl->mctx, 0, sizeof(dl->mctx)); |
| dl->mctx.dl = dl; |
| dl->mctx.n201 = n201; |
| dl->mctx.chan_nr = chan_nr; |
| dl->mctx.link_id = link_id; |
| |
| rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); |
| if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { |
| LOGP(DLLAPDM, LOGL_ERROR, "resume without message error\n"); |
| msgb_free(msg); |
| return send_rll_simple(RSL_MT_REL_IND, &dl->mctx); |
| } |
| length = TLVP_LEN(&tv, RSL_IE_L3_INFO); |
| |
| LOGP(DLLAPDM, LOGL_INFO, "perform re-establishment (SABM) length=%d\n", |
| length); |
| |
| /* Replace message in the send-buffer (reconnect) */ |
| if (dl->send_buffer) |
| msgb_free(dl->send_buffer); |
| dl->send_out = 0; |
| if (length) { |
| /* Remove the RSL/RLL header */ |
| msgb_pull_l2h(msg); |
| /* Write data into the send buffer, to be sent first */ |
| dl->send_buffer = msg; |
| } |
| |
| /* Discard partly received L3 message */ |
| if (dl->rcv_buffer) { |
| msgb_free(dl->rcv_buffer); |
| dl->rcv_buffer = NULL; |
| } |
| |
| /* Create new msgb (old one is now free) */ |
| msg = msgb_alloc_headroom(23+10, 10, "LAPDm SABM"); |
| msg->l2h = msgb_put(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); |
| msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_SABM, 1); |
| msg->l2h[2] = LAPDm_LEN(0); |
| /* Transmit-buffer carries exactly one segment */ |
| memcpy(dl->tx_hist[0], msg->l2h, 3); |
| dl->tx_length[0] = 3; |
| /* set Vs to 0, because it is used as index when resending SABM */ |
| dl->V_send = 0; |
| |
| /* Set states */ |
| dl->own_busy = dl->peer_busy = 0; |
| dl->retrans_ctr = 0; |
| lapdm_dl_newstate(dl, LAPDm_STATE_SABM_SENT); |
| |
| /* Tramsmit and start T200 */ |
| osmo_timer_schedule(&dl->t200, T200); |
| return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); |
| } |
| |
| /* L3 requests release of data link */ |
| static int rslms_rx_rll_rel_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 = rllh->link_id & 7; |
| uint8_t mode = 0; |
| |
| /* get release mode */ |
| if (rllh->data[0] == RSL_IE_RELEASE_MODE) |
| mode = rllh->data[1] & 1; |
| |
| /* local release */ |
| if (mode) { |
| LOGP(DLLAPDM, LOGL_INFO, "perform local release\n"); |
| msgb_free(msg); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* enter idle state */ |
| lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); |
| /* flush buffers */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| /* send notification to L3 */ |
| return send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); |
| } |
| |
| /* in case we are already disconnecting */ |
| if (dl->state == LAPDm_STATE_DISC_SENT) |
| return -EBUSY; |
| |
| LOGP(DLLAPDM, LOGL_INFO, "perform normal release (DISC)\n"); |
| |
| /* Pull rllh */ |
| msgb_pull(msg, msg->tail - msg->l2h); |
| |
| /* Push LAPDm header on msgb */ |
| msg->l2h = msgb_push(msg, 3); |
| msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); |
| msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_DISC, 1); |
| msg->l2h[2] = LAPDm_LEN(0); |
| /* Transmit-buffer carries exactly one segment */ |
| memcpy(dl->tx_hist[0], msg->l2h, 3); |
| dl->tx_length[0] = 3; |
| |
| /* Set states */ |
| dl->own_busy = dl->peer_busy = 0; |
| dl->retrans_ctr = 0; |
| lapdm_dl_newstate(dl, LAPDm_STATE_DISC_SENT); |
| |
| /* Tramsmit and start T200 */ |
| osmo_timer_schedule(&dl->t200, T200); |
| return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, dl->mctx.n201); |
| } |
| |
| /* L3 requests release in idle state */ |
| static int rslms_rx_rll_rel_req_idle(struct msgb *msg, struct lapdm_datalink *dl) |
| { |
| msgb_free(msg); |
| |
| /* send notification to L3 */ |
| return send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); |
| } |
| |
| /* 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(DLLAPDM, LOGL_ERROR, "Message too short for CHAN RQD!\n"); |
| return -EINVAL; |
| } |
| if (cch->data[0] != RSL_IE_REQ_REFERENCE) { |
| LOGP(DLLAPDM, 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(DLLAPDM, 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(DLLAPDM, 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_l2h(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); |
| } |
| |
| const char *lapdm_state_names[] = { |
| "LAPDm_STATE_NULL", |
| "LAPDm_STATE_IDLE", |
| "LAPDm_STATE_SABM_SENT", |
| "LAPDm_STATE_MF_EST", |
| "LAPDm_STATE_TIMER_RECOV", |
| "LAPDm_STATE_DISC_SENT", |
| }; |
| |
| /* statefull handling for RSLms RLL messages from L3 */ |
| static struct l2downstate { |
| uint32_t states; |
| int type; |
| int (*rout) (struct msgb *msg, struct lapdm_datalink *dl); |
| } l2downstatelist[] = { |
| /* create and send UI command */ |
| {ALL_STATES, |
| RSL_MT_UNIT_DATA_REQ, rslms_rx_rll_udata_req}, |
| |
| /* create and send SABM command */ |
| {SBIT(LAPDm_STATE_IDLE), |
| RSL_MT_EST_REQ, rslms_rx_rll_est_req}, |
| |
| /* create and send I command */ |
| {SBIT(LAPDm_STATE_MF_EST) | |
| SBIT(LAPDm_STATE_TIMER_RECOV), |
| RSL_MT_DATA_REQ, rslms_rx_rll_data_req}, |
| |
| /* suspend datalink */ |
| {SBIT(LAPDm_STATE_MF_EST) | |
| SBIT(LAPDm_STATE_TIMER_RECOV), |
| RSL_MT_SUSP_REQ, rslms_rx_rll_susp_req}, |
| |
| /* create and send SABM command (resume) */ |
| {SBIT(LAPDm_STATE_MF_EST) | |
| SBIT(LAPDm_STATE_TIMER_RECOV), |
| RSL_MT_RES_REQ, rslms_rx_rll_res_req}, |
| |
| /* create and send SABM command (reconnect) */ |
| {SBIT(LAPDm_STATE_IDLE) | |
| SBIT(LAPDm_STATE_MF_EST) | |
| SBIT(LAPDm_STATE_TIMER_RECOV), |
| RSL_MT_RECON_REQ, rslms_rx_rll_res_req}, |
| |
| /* create and send DISC command */ |
| {SBIT(LAPDm_STATE_SABM_SENT) | |
| SBIT(LAPDm_STATE_MF_EST) | |
| SBIT(LAPDm_STATE_TIMER_RECOV) | |
| SBIT(LAPDm_STATE_DISC_SENT), |
| RSL_MT_REL_REQ, rslms_rx_rll_rel_req}, |
| |
| /* release in idle state */ |
| {SBIT(LAPDm_STATE_IDLE), |
| RSL_MT_REL_REQ, rslms_rx_rll_rel_req_idle}, |
| }; |
| |
| #define L2DOWNSLLEN \ |
| (sizeof(l2downstatelist) / sizeof(struct l2downstate)) |
| |
| /* 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 i, supported = 0; |
| int rc = 0; |
| |
| if (msgb_l2len(msg) < sizeof(*rllh)) { |
| LOGP(DLLAPDM, LOGL_ERROR, "Message too short for RLL hdr!\n"); |
| return -EINVAL; |
| } |
| |
| if (rllh->link_id & 0x40) |
| le = &lc->lapdm_acch; |
| else |
| le = &lc->lapdm_dcch; |
| |
| /* G.2.1 No action schall be taken on frames containing an unallocated |
| * SAPI. |
| */ |
| dl = datalink_for_sapi(le, sapi); |
| if (!dl) { |
| LOGP(DLLAPDM, LOGL_ERROR, "No instance for SAPI %d!\n", sapi); |
| return -EINVAL; |
| } |
| |
| LOGP(DLLAPDM, LOGL_INFO, "(%p) RLL Message '%s' received in state %s\n", |
| lc->name, rsl_msg_name(msg_type), lapdm_state_names[dl->state]); |
| |
| /* find function for current state and message */ |
| for (i = 0; i < L2DOWNSLLEN; i++) { |
| if (msg_type == l2downstatelist[i].type) |
| supported = 1; |
| if ((msg_type == l2downstatelist[i].type) |
| && ((1 << dl->state) & l2downstatelist[i].states)) |
| break; |
| } |
| if (!supported) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "Message unsupported.\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| if (i == L2DOWNSLLEN) { |
| LOGP(DLLAPDM, LOGL_NOTICE, "Message unhandled at this state.\n"); |
| msgb_free(msg); |
| return 0; |
| } |
| |
| rc = l2downstatelist[i].rout(msg, dl); |
| |
| 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(DLLAPDM, 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(DLLAPDM, LOGL_NOTICE, "Unknown COMMON CHANNEL msg %d!\n", |
| msg_type); |
| msgb_free(msg); |
| return 0; |
| } |
| |
| return rc; |
| } |
| |
| /*! \brief Receive a RSLms \ref msgb from Layer 3 */ |
| 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(DLLAPDM, LOGL_ERROR, "Message too short RSL hdr!\n"); |
| 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(DLLAPDM, LOGL_ERROR, "unknown RSLms message " |
| "discriminator 0x%02x", rslh->msg_discr); |
| msgb_free(msg); |
| return -EINVAL; |
| } |
| |
| return rc; |
| } |
| |
| /*! \brief Set the \ref lapdm_mode of a LAPDm entity */ |
| int lapdm_entity_set_mode(struct lapdm_entity *le, enum lapdm_mode mode) |
| { |
| switch (mode) { |
| case LAPDM_MODE_MS: |
| le->cr.loc2rem.cmd = CR_MS2BS_CMD; |
| le->cr.loc2rem.resp = CR_MS2BS_RESP; |
| le->cr.rem2loc.cmd = CR_BS2MS_CMD; |
| le->cr.rem2loc.resp = CR_BS2MS_RESP; |
| break; |
| case LAPDM_MODE_BTS: |
| le->cr.loc2rem.cmd = CR_BS2MS_CMD; |
| le->cr.loc2rem.resp = CR_BS2MS_RESP; |
| le->cr.rem2loc.cmd = CR_MS2BS_CMD; |
| le->cr.rem2loc.resp = CR_MS2BS_RESP; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| le->mode = mode; |
| |
| return 0; |
| } |
| |
| /*! \brief 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); |
| } |
| |
| /*! \brief 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; |
| } |
| |
| /*! \brief 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; |
| } |
| |
| /*! \brief 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]; |
| if (dl->state == LAPDm_STATE_IDLE) |
| continue; |
| LOGP(DLLAPDM, LOGL_INFO, "Resetting LAPDm instance\n"); |
| /* reset Timer T200 */ |
| osmo_timer_del(&dl->t200); |
| /* enter idle state */ |
| dl->state = LAPDm_STATE_IDLE; |
| /* flush buffer */ |
| lapdm_dl_flush_tx(dl); |
| lapdm_dl_flush_send(dl); |
| } |
| } |
| |
| /*! \brief 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); |
| } |
| |
| /*! \brief Set the flags of a LAPDm entity */ |
| void lapdm_entity_set_flags(struct lapdm_entity *le, unsigned int flags) |
| { |
| le->flags = flags; |
| } |
| |
| /*! \brief 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); |
| } |
| |
| /*! }@ */ |