mirror of https://gerrit.osmocom.org/libosmocore
2243 lines
63 KiB
C
2243 lines
63 KiB
C
/* LAPD core implementation */
|
|
|
|
/* (C) 2010-2011 by Harald Welte <laforge@gnumonks.org>
|
|
* (C) 2010-2011 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 lapd
|
|
* @{
|
|
* \brief Osmocom LAPD core, used for Q.921, LAPDm and others
|
|
*/
|
|
|
|
/*! \file lapd_core.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.
|
|
*
|
|
* T203 is optional. It will be stated when entering MF EST state. It will also
|
|
* be started when I or S frame is received in that state . It will be
|
|
* restarted in the lapd_acknowledge() function, in case outstanding frames
|
|
* will not trigger T200. It will be stoped, when T200 is started in MF EST
|
|
* state. It will also be stoped when leaving MF EST state.
|
|
*
|
|
*/
|
|
|
|
/* Enable this to test content resolution on network side:
|
|
* - The first SABM is received, UA is dropped.
|
|
* - The phone repeats SABM, but it's content is wrong, so it is ignored
|
|
* - The phone repeats SABM again, content is right, so UA is sent.
|
|
*/
|
|
//#define TEST_CONTENT_RESOLUTION_NETWORK
|
|
|
|
#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/core/talloc.h>
|
|
#include <osmocom/gsm/lapd_core.h>
|
|
#include <osmocom/gsm/rsl.h>
|
|
|
|
/* TS 04.06 Table 4 / Section 3.8.1 */
|
|
#define LAPD_U_SABM 0x7
|
|
#define LAPD_U_SABME 0xf
|
|
#define LAPD_U_DM 0x3
|
|
#define LAPD_U_UI 0x0
|
|
#define LAPD_U_DISC 0x8
|
|
#define LAPD_U_UA 0xC
|
|
#define LAPD_U_FRMR 0x11
|
|
|
|
#define LAPD_S_RR 0x0
|
|
#define LAPD_S_RNR 0x1
|
|
#define LAPD_S_REJ 0x2
|
|
|
|
#define CR_USER2NET_CMD 0
|
|
#define CR_USER2NET_RESP 1
|
|
#define CR_NET2USER_CMD 1
|
|
#define CR_NET2USER_RESP 0
|
|
|
|
#define LAPD_HEADROOM 56
|
|
|
|
#define SBIT(a) (1 << a)
|
|
#define ALL_STATES 0xffffffff
|
|
|
|
static void lapd_t200_cb(void *data);
|
|
static void lapd_t203_cb(void *data);
|
|
static int lapd_send_i(struct lapd_msg_ctx *lctx, int line);
|
|
static int lapd_est_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx);
|
|
|
|
/* UTILITY FUNCTIONS */
|
|
|
|
struct msgb *lapd_msgb_alloc(int length, const char *name)
|
|
{
|
|
/* adding space for padding, FIXME: add as an option */
|
|
if (length < 21)
|
|
length = 21;
|
|
return msgb_alloc_headroom(length + LAPD_HEADROOM, LAPD_HEADROOM, name);
|
|
}
|
|
|
|
static inline uint8_t do_mod(uint8_t x, uint8_t m)
|
|
{
|
|
return x & (m - 1);
|
|
}
|
|
|
|
static inline uint8_t inc_mod(uint8_t x, uint8_t m)
|
|
{
|
|
return (x + 1) & (m - 1);
|
|
}
|
|
|
|
static inline uint8_t add_mod(uint8_t x, uint8_t y, uint8_t m)
|
|
{
|
|
return (x + y) & (m - 1);
|
|
}
|
|
|
|
static inline uint8_t sub_mod(uint8_t x, uint8_t y, uint8_t m)
|
|
{
|
|
return (x - y) & (m - 1); /* handle negative results correctly */
|
|
}
|
|
|
|
static void lapd_dl_flush_send(struct lapd_datalink *dl)
|
|
{
|
|
struct msgb *msg;
|
|
|
|
/* Flush send-queue */
|
|
while ((msg = msgb_dequeue(&dl->send_queue)))
|
|
msgb_free(msg);
|
|
|
|
/* Clear send-buffer */
|
|
msgb_free(dl->send_buffer);
|
|
dl->send_buffer = NULL;
|
|
}
|
|
|
|
static void lapd_dl_flush_hist(struct lapd_datalink *dl)
|
|
{
|
|
unsigned int i;
|
|
|
|
if (!dl->range_hist || !dl->tx_hist)
|
|
return;
|
|
|
|
for (i = 0; i < dl->range_hist; i++) {
|
|
if (dl->tx_hist[i].msg) {
|
|
msgb_free(dl->tx_hist[i].msg);
|
|
dl->tx_hist[i].msg = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void lapd_dl_flush_tx(struct lapd_datalink *dl)
|
|
{
|
|
struct msgb *msg;
|
|
|
|
while ((msg = msgb_dequeue(&dl->tx_queue)))
|
|
msgb_free(msg);
|
|
lapd_dl_flush_hist(dl);
|
|
}
|
|
|
|
/* Figure B.2/Q.921 */
|
|
const struct value_string lapd_state_names[] = {
|
|
OSMO_VALUE_STRING(LAPD_STATE_NULL),
|
|
OSMO_VALUE_STRING(LAPD_STATE_TEI_UNASS),
|
|
OSMO_VALUE_STRING(LAPD_STATE_ASS_TEI_WAIT),
|
|
OSMO_VALUE_STRING(LAPD_STATE_EST_TEI_WAIT),
|
|
OSMO_VALUE_STRING(LAPD_STATE_IDLE),
|
|
OSMO_VALUE_STRING(LAPD_STATE_SABM_SENT),
|
|
OSMO_VALUE_STRING(LAPD_STATE_DISC_SENT),
|
|
OSMO_VALUE_STRING(LAPD_STATE_MF_EST),
|
|
OSMO_VALUE_STRING(LAPD_STATE_TIMER_RECOV),
|
|
{ 0, NULL }
|
|
};
|
|
|
|
static inline const char *lapd_state_name(enum lapd_state state)
|
|
{
|
|
return get_value_string(lapd_state_names, state);
|
|
}
|
|
|
|
static void lapd_start_t200(struct lapd_datalink *dl)
|
|
{
|
|
if (osmo_timer_pending(&dl->t200))
|
|
return;
|
|
LOGP(DLLAPD, LOGL_INFO, "start T200 (dl=%p)\n", dl);
|
|
osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec);
|
|
}
|
|
|
|
static void lapd_start_t203(struct lapd_datalink *dl)
|
|
{
|
|
if (osmo_timer_pending(&dl->t203))
|
|
return;
|
|
LOGP(DLLAPD, LOGL_INFO, "start T203 (dl=%p)\n", dl);
|
|
osmo_timer_schedule(&dl->t203, dl->t203_sec, dl->t203_usec);
|
|
}
|
|
|
|
static void lapd_stop_t200(struct lapd_datalink *dl)
|
|
{
|
|
if (!osmo_timer_pending(&dl->t200))
|
|
return;
|
|
LOGP(DLLAPD, LOGL_INFO, "stop T200 (dl=%p)\n", dl);
|
|
osmo_timer_del(&dl->t200);
|
|
}
|
|
|
|
static void lapd_stop_t203(struct lapd_datalink *dl)
|
|
{
|
|
if (!osmo_timer_pending(&dl->t203))
|
|
return;
|
|
LOGP(DLLAPD, LOGL_INFO, "stop T203 (dl=%p)\n", dl);
|
|
osmo_timer_del(&dl->t203);
|
|
}
|
|
|
|
static void lapd_dl_newstate(struct lapd_datalink *dl, uint32_t state)
|
|
{
|
|
LOGP(DLLAPD, LOGL_INFO, "new state %s -> %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), lapd_state_name(state), dl);
|
|
|
|
if (state != LAPD_STATE_MF_EST && dl->state == LAPD_STATE_MF_EST) {
|
|
/* stop T203 on leaving MF EST state, if running */
|
|
lapd_stop_t203(dl);
|
|
/* remove content res. (network side) on leaving MF EST state */
|
|
msgb_free(dl->cont_res);
|
|
dl->cont_res = NULL;
|
|
}
|
|
|
|
/* start T203 on entering MF EST state, if enabled */
|
|
if ((dl->t203_sec || dl->t203_usec)
|
|
&& state == LAPD_STATE_MF_EST && dl->state != LAPD_STATE_MF_EST)
|
|
lapd_start_t203(dl);
|
|
|
|
dl->state = state;
|
|
}
|
|
|
|
static void *tall_lapd_ctx = NULL;
|
|
|
|
/* init datalink instance and allocate history */
|
|
void lapd_dl_init(struct lapd_datalink *dl, uint8_t k, uint8_t v_range,
|
|
int maxf)
|
|
{
|
|
int m;
|
|
|
|
memset(dl, 0, sizeof(*dl));
|
|
INIT_LLIST_HEAD(&dl->send_queue);
|
|
INIT_LLIST_HEAD(&dl->tx_queue);
|
|
dl->reestablish = 1;
|
|
dl->n200_est_rel = 3;
|
|
dl->n200 = 3;
|
|
dl->t200_sec = 1;
|
|
dl->t200_usec = 0;
|
|
osmo_timer_setup(&dl->t200, lapd_t200_cb, dl);
|
|
dl->t203_sec = 10;
|
|
dl->t203_usec = 0;
|
|
osmo_timer_setup(&dl->t203, lapd_t203_cb, dl);
|
|
dl->maxf = maxf;
|
|
if (k > v_range - 1)
|
|
k = v_range - 1;
|
|
dl->k = k;
|
|
dl->v_range = v_range;
|
|
|
|
/* Calculate modulo for history array:
|
|
* - The history range must be at least k+1.
|
|
* - The history range must be 2^x, where x is as low as possible.
|
|
*/
|
|
k++;
|
|
for (m = 0x80; m; m >>= 1) {
|
|
if ((m & k)) {
|
|
if (k > m)
|
|
m <<= 1;
|
|
dl->range_hist = m;
|
|
break;
|
|
}
|
|
}
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "Init DL layer: sequence range = %d, k = %d, "
|
|
"history range = %d (dl=%p)\n", dl->v_range, dl->k,
|
|
dl->range_hist, dl);
|
|
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
|
|
if (!tall_lapd_ctx)
|
|
tall_lapd_ctx = talloc_named_const(NULL, 1, "lapd context");
|
|
dl->tx_hist = talloc_zero_array(tall_lapd_ctx,
|
|
struct lapd_history, dl->range_hist);
|
|
}
|
|
|
|
/* reset to IDLE state */
|
|
void lapd_dl_reset(struct lapd_datalink *dl)
|
|
{
|
|
/* flush buffer */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
/* Discard partly received L3 message */
|
|
msgb_free(dl->rcv_buffer);
|
|
dl->rcv_buffer = NULL;
|
|
/* stop Timers */
|
|
lapd_stop_t200(dl);
|
|
lapd_stop_t203(dl);
|
|
if (dl->state == LAPD_STATE_IDLE)
|
|
return;
|
|
LOGP(DLLAPD, LOGL_INFO, "Resetting LAPDm instance (dl=%p)\n", dl);
|
|
/* enter idle state (and remove eventual cont_res) */
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
}
|
|
|
|
/* reset and de-allocate history buffer */
|
|
void lapd_dl_exit(struct lapd_datalink *dl)
|
|
{
|
|
/* free all ressources except history buffer */
|
|
lapd_dl_reset(dl);
|
|
/* free history buffer list */
|
|
talloc_free(dl->tx_hist);
|
|
dl->tx_hist = NULL;
|
|
}
|
|
|
|
/*! \brief Set the \ref lapdm_mode of a LAPDm entity */
|
|
int lapd_set_mode(struct lapd_datalink *dl, enum lapd_mode mode)
|
|
{
|
|
switch (mode) {
|
|
case LAPD_MODE_USER:
|
|
dl->cr.loc2rem.cmd = CR_USER2NET_CMD;
|
|
dl->cr.loc2rem.resp = CR_USER2NET_RESP;
|
|
dl->cr.rem2loc.cmd = CR_NET2USER_CMD;
|
|
dl->cr.rem2loc.resp = CR_NET2USER_RESP;
|
|
break;
|
|
case LAPD_MODE_NETWORK:
|
|
dl->cr.loc2rem.cmd = CR_NET2USER_CMD;
|
|
dl->cr.loc2rem.resp = CR_NET2USER_RESP;
|
|
dl->cr.rem2loc.cmd = CR_USER2NET_CMD;
|
|
dl->cr.rem2loc.resp = CR_USER2NET_RESP;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
dl->mode = mode;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* send DL message with optional msgb */
|
|
static int send_dl_l3(uint8_t prim, uint8_t op, struct lapd_msg_ctx *lctx,
|
|
struct msgb *msg)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
osmo_prim_init(&dp.oph, 0, prim, op, msg);
|
|
return dl->send_dlsap(&dp, lctx);
|
|
}
|
|
|
|
/* send simple DL message */
|
|
static inline int send_dl_simple(uint8_t prim, uint8_t op,
|
|
struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(0, "DUMMY");
|
|
|
|
return send_dl_l3(prim, op, lctx, msg);
|
|
}
|
|
|
|
/* send MDL-ERROR INDICATION */
|
|
static int mdl_error(uint8_t cause, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct osmo_dlsap_prim dp;
|
|
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"sending MDL-ERROR-IND cause %d from state %s (dl=%p)\n",
|
|
cause, lapd_state_name(dl->state), dl);
|
|
osmo_prim_init(&dp.oph, 0, PRIM_MDL_ERROR, PRIM_OP_INDICATION, NULL);
|
|
dp.u.error_ind.cause = cause;
|
|
return dl->send_dlsap(&dp, lctx);
|
|
}
|
|
|
|
/* send UA response */
|
|
static int lapd_send_ua(struct lapd_msg_ctx *lctx, uint8_t len, uint8_t *data)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(len, "LAPD UA");
|
|
struct lapd_msg_ctx nctx;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
msg->l3h = msgb_put(msg, len);
|
|
if (len)
|
|
memcpy(msg->l3h, data, len);
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.resp;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = LAPD_U_UA;
|
|
/* keep nctx.p_f */
|
|
nctx.length = len;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* send DM response */
|
|
static int lapd_send_dm(struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(0, "LAPD DM");
|
|
struct lapd_msg_ctx nctx;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.resp;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = LAPD_U_DM;
|
|
/* keep nctx.p_f */
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* send RR response / command */
|
|
static int lapd_send_rr(struct lapd_msg_ctx *lctx, uint8_t f_bit, uint8_t cmd)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(0, "LAPD RR");
|
|
struct lapd_msg_ctx nctx;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = (cmd) ? dl->cr.loc2rem.cmd : dl->cr.loc2rem.resp;
|
|
nctx.format = LAPD_FORM_S;
|
|
nctx.s_u = LAPD_S_RR;
|
|
nctx.p_f = f_bit;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* send RNR response / command */
|
|
static int lapd_send_rnr(struct lapd_msg_ctx *lctx, uint8_t f_bit, uint8_t cmd)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(0, "LAPD RNR");
|
|
struct lapd_msg_ctx nctx;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = (cmd) ? dl->cr.loc2rem.cmd : dl->cr.loc2rem.resp;
|
|
nctx.format = LAPD_FORM_S;
|
|
nctx.s_u = LAPD_S_RNR;
|
|
nctx.p_f = f_bit;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* send REJ response */
|
|
static int lapd_send_rej(struct lapd_msg_ctx *lctx, uint8_t f_bit)
|
|
{
|
|
struct msgb *msg = lapd_msgb_alloc(0, "LAPD REJ");
|
|
struct lapd_msg_ctx nctx;
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.resp;
|
|
nctx.format = LAPD_FORM_S;
|
|
nctx.s_u = LAPD_S_REJ;
|
|
nctx.p_f = f_bit;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* resend SABM or DISC message */
|
|
static int lapd_send_resend(struct lapd_datalink *dl)
|
|
{
|
|
struct msgb *msg;
|
|
uint8_t h = do_mod(dl->v_send, dl->range_hist);
|
|
int length = dl->tx_hist[h].msg->len;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_U;
|
|
if (dl->state == LAPD_STATE_SABM_SENT)
|
|
nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM;
|
|
else
|
|
nctx.s_u = LAPD_U_DISC;
|
|
nctx.p_f = 1;
|
|
nctx.length = length;
|
|
nctx.more = 0;
|
|
|
|
/* Resend SABM/DISC from tx_hist */
|
|
msg = lapd_msgb_alloc(length, "LAPD resend");
|
|
msg->l3h = msgb_put(msg, length);
|
|
if (length)
|
|
memcpy(msg->l3h, dl->tx_hist[h].msg->data, length);
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* reestablish link */
|
|
static int lapd_reestablish(struct lapd_datalink *dl)
|
|
{
|
|
struct osmo_dlsap_prim dp;
|
|
struct msgb *msg;
|
|
|
|
LOGP(DLLAPD, LOGL_DEBUG, "lapd reestablish (dl=%p)\n", dl);
|
|
|
|
msg = lapd_msgb_alloc(0, "DUMMY");
|
|
osmo_prim_init(&dp.oph, 0, PRIM_DL_EST, PRIM_OP_REQUEST, msg);
|
|
|
|
return lapd_est_req(&dp, &dl->lctx);
|
|
}
|
|
|
|
/* Timer callback on T200 expiry */
|
|
static void lapd_t200_cb(void *data)
|
|
{
|
|
struct lapd_datalink *dl = data;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "Timeout T200 state=%s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
|
|
switch (dl->state) {
|
|
case LAPD_STATE_SABM_SENT:
|
|
/* 5.4.1.3 */
|
|
if (dl->retrans_ctr + 1 >= dl->n200_est_rel + 1) {
|
|
/* flush tx and send buffers */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
/* go back to idle state */
|
|
lapd_dl_newstate(dl, LAPD_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 */
|
|
/* send MDL ERROR INIDCATION to L3 */
|
|
mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx);
|
|
/* send RELEASE INDICATION to L3 */
|
|
send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION,
|
|
&dl->lctx);
|
|
break;
|
|
}
|
|
/* retransmit SABM command */
|
|
lapd_send_resend(dl);
|
|
/* increment re-transmission counter */
|
|
dl->retrans_ctr++;
|
|
/* restart T200 (PH-READY-TO-SEND) */
|
|
lapd_start_t200(dl);
|
|
break;
|
|
case LAPD_STATE_DISC_SENT:
|
|
/* 5.4.4.3 */
|
|
if (dl->retrans_ctr + 1 >= dl->n200_est_rel + 1) {
|
|
/* send MDL ERROR INIDCATION to L3 */
|
|
mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx);
|
|
/* send RELEASE INDICATION to L3 */
|
|
send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx);
|
|
/* flush tx and send buffers */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
/* go back to idle state */
|
|
lapd_dl_newstate(dl, LAPD_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 */
|
|
lapd_send_resend(dl);
|
|
/* increment re-transmission counter */
|
|
dl->retrans_ctr++;
|
|
/* restart T200 (PH-READY-TO-SEND) */
|
|
lapd_start_t200(dl);
|
|
break;
|
|
case LAPD_STATE_MF_EST:
|
|
/* 5.5.7 */
|
|
dl->retrans_ctr = 0;
|
|
lapd_dl_newstate(dl, LAPD_STATE_TIMER_RECOV);
|
|
/* fall through */
|
|
case LAPD_STATE_TIMER_RECOV:
|
|
dl->retrans_ctr++;
|
|
if (dl->retrans_ctr < dl->n200) {
|
|
uint8_t vs = sub_mod(dl->v_send, 1, dl->v_range);
|
|
uint8_t h = do_mod(vs, dl->range_hist);
|
|
/* retransmit I frame (V_s-1) with P=1, if any */
|
|
if (dl->tx_hist[h].msg) {
|
|
struct msgb *msg;
|
|
int length = dl->tx_hist[h].msg->len;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "retransmit last frame"
|
|
" V(S)=%d (dl=%p)\n", vs, dl);
|
|
/* Create I frame (segment) from tx_hist */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_I;
|
|
nctx.p_f = 1;
|
|
nctx.n_send = vs;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = length;
|
|
nctx.more = dl->tx_hist[h].more;
|
|
msg = lapd_msgb_alloc(length, "LAPD I resend");
|
|
msg->l3h = msgb_put(msg, length);
|
|
memcpy(msg->l3h, dl->tx_hist[h].msg->data,
|
|
length);
|
|
dl->send_ph_data_req(&nctx, msg);
|
|
} else {
|
|
/* OR send appropriate supervision frame with P=1 */
|
|
if (!dl->own_busy && !dl->seq_err_cond) {
|
|
lapd_send_rr(&dl->lctx, 1, 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) {
|
|
lapd_send_rnr(&dl->lctx, 1, 1);
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO, "unhandled, "
|
|
"pls. fix (dl=%p)\n", dl);
|
|
}
|
|
}
|
|
/* restart T200 (PH-READY-TO-SEND) */
|
|
lapd_start_t200(dl);
|
|
} else {
|
|
/* send MDL ERROR INIDCATION to L3 */
|
|
mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx);
|
|
/* reestablish */
|
|
if (!dl->reestablish)
|
|
break;
|
|
LOGP(DLLAPD, LOGL_NOTICE, "N200 reached, performing "
|
|
"reestablishment. (dl=%p)\n", dl);
|
|
lapd_reestablish(dl);
|
|
}
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_INFO, "T200 expired in unexpected "
|
|
"dl->state %s (dl=%p)\n", lapd_state_name(dl->state), dl);
|
|
}
|
|
}
|
|
|
|
/* Timer callback on T203 expiry */
|
|
static void lapd_t203_cb(void *data)
|
|
{
|
|
struct lapd_datalink *dl = data;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "Timeout T203 state=%s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
|
|
if (dl->state != LAPD_STATE_MF_EST) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "T203 fired outside MF EST state, "
|
|
"please fix! (dl=%p)\n", dl);
|
|
return;
|
|
}
|
|
|
|
/* set retransmission counter to 0 */
|
|
dl->retrans_ctr = 0;
|
|
/* enter timer recovery state */
|
|
lapd_dl_newstate(dl, LAPD_STATE_TIMER_RECOV);
|
|
/* transmit a supervisory command with P bit set to 1 as follows: */
|
|
if (!dl->own_busy) {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"transmit an RR poll command (dl=%p)\n", dl);
|
|
/* Send RR with P=1 */
|
|
lapd_send_rr(&dl->lctx, 1, 1);
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"transmit an RNR poll command (dl=%p)\n", dl);
|
|
/* Send RNR with P=1 */
|
|
lapd_send_rnr(&dl->lctx, 1, 1);
|
|
}
|
|
/* start T200 */
|
|
lapd_start_t200(dl);
|
|
}
|
|
|
|
/* 5.5.3.1: Common function to acknowlege frames up to the given N(R) value */
|
|
static void lapd_acknowledge(struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
uint8_t nr = lctx->n_recv;
|
|
int s = 0, rej = 0, t200_reset = 0;
|
|
int i, h;
|
|
|
|
/* supervisory frame ? */
|
|
if (lctx->format == LAPD_FORM_S)
|
|
s = 1;
|
|
/* REJ frame ? */
|
|
if (s && lctx->s_u == LAPD_S_REJ)
|
|
rej = 1;
|
|
|
|
/* Flush all transmit buffers of acknowledged frames */
|
|
for (i = dl->v_ack; i != nr; i = inc_mod(i, dl->v_range)) {
|
|
h = do_mod(i, dl->range_hist);
|
|
if (dl->tx_hist[h].msg) {
|
|
msgb_free(dl->tx_hist[h].msg);
|
|
dl->tx_hist[h].msg = NULL;
|
|
LOGP(DLLAPD, LOGL_INFO, "ack frame %d\n", i);
|
|
}
|
|
}
|
|
|
|
if (dl->state != LAPD_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)) {
|
|
t200_reset = 1;
|
|
lapd_stop_t200(dl);
|
|
/* 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_mod(nr, dl->v_ack, dl->v_range)
|
|
> sub_mod(dl->v_send, dl->v_ack, dl->v_range)) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "N(R) sequence error (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_SEQ_ERR, lctx);
|
|
}
|
|
}
|
|
|
|
/* V(A) shall be set to the value of N(R) */
|
|
dl->v_ack = nr;
|
|
|
|
/* If T200 has been stopped 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_hist[sub_mod(dl->v_send, 1, dl->range_hist)].msg) {
|
|
LOGP(DLLAPD, LOGL_INFO, "start T200, due to unacked I "
|
|
"frame(s) (dl=%p)\n", dl);
|
|
lapd_start_t200(dl);
|
|
}
|
|
}
|
|
|
|
/* This also does a restart, when I or S frame is received */
|
|
|
|
/* Stop T203, if running */
|
|
lapd_stop_t203(dl);
|
|
/* Start T203, if T200 is not running in MF EST state, if enabled */
|
|
if (!osmo_timer_pending(&dl->t200)
|
|
&& (dl->t203_sec || dl->t203_usec)
|
|
&& (dl->state == LAPD_STATE_MF_EST)) {
|
|
lapd_start_t203(dl);
|
|
}
|
|
}
|
|
|
|
/* L1 -> L2 */
|
|
|
|
/* Receive a LAPD U (Unnumbered) message from L1 */
|
|
static int lapd_rx_u(struct msgb *msg, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
int length = lctx->length;
|
|
int rc = 0;
|
|
uint8_t prim, op;
|
|
|
|
switch (lctx->s_u) {
|
|
case LAPD_U_SABM:
|
|
case LAPD_U_SABME:
|
|
prim = PRIM_DL_EST;
|
|
op = PRIM_OP_INDICATION;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "SABM(E) received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* 5.7.1 */
|
|
dl->seq_err_cond = 0;
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.resp) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"SABM response error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* G.4.5 If SABM is received with L>N201 or with M bit
|
|
* set, AN MDL-ERROR-INDICATION is sent to MM.
|
|
*/
|
|
if (lctx->more || length > lctx->n201) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"SABM too large error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx);
|
|
return -EIO;
|
|
}
|
|
|
|
switch (dl->state) {
|
|
case LAPD_STATE_IDLE:
|
|
break;
|
|
case LAPD_STATE_MF_EST:
|
|
LOGP(DLLAPD, LOGL_INFO, "SABM command, multiple "
|
|
"frame established state (dl=%p)\n", dl);
|
|
/* If link is lost on the remote side, we start over
|
|
* and send DL-ESTABLISH indication again. */
|
|
/* Additionally, continue in case of content resoltion
|
|
* (GSM network). This happens, if the mobile has not
|
|
* yet received UA or another mobile (collision) tries
|
|
* to establish connection. The mobile must receive
|
|
* UA again. */
|
|
/* 5.4.2.1 */
|
|
if (!length) {
|
|
/* If no content resolution, this is a
|
|
* re-establishment. */
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"Remote reestablish (dl=%p)\n", dl);
|
|
break;
|
|
}
|
|
if (!dl->cont_res) {
|
|
LOGP(DLLAPD, LOGL_INFO, "SABM command not "
|
|
"allowed in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
mdl_error(MDL_CAUSE_SABM_MF, lctx);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
/* Ignore SABM if content differs from first SABM. */
|
|
if (dl->mode == LAPD_MODE_NETWORK && length) {
|
|
#ifdef TEST_CONTENT_RESOLUTION_NETWORK
|
|
dl->cont_res->data[0] ^= 0x01;
|
|
#endif
|
|
if (memcmp(dl->cont_res->data, msg->data,
|
|
length)) {
|
|
LOGP(DLLAPD, LOGL_INFO, "Another SABM "
|
|
"with different content - "
|
|
"ignoring! (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
}
|
|
/* send UA again */
|
|
lapd_send_ua(lctx, length, msg->l3h);
|
|
msgb_free(msg);
|
|
return 0;
|
|
case LAPD_STATE_DISC_SENT:
|
|
/* 5.4.6.2 send DM with F=P */
|
|
lapd_send_dm(lctx);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
msgb_free(msg);
|
|
return send_dl_simple(prim, op, lctx);
|
|
default:
|
|
/* collision: Send UA, but still wait for rx UA, then
|
|
* change to MF_EST state.
|
|
*/
|
|
/* check for contention resoultion */
|
|
if (dl->tx_hist[0].msg && dl->tx_hist[0].msg->len) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "SABM not allowed "
|
|
"during contention resolution (state=%s, dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
mdl_error(MDL_CAUSE_SABM_INFO_NOTALL, lctx);
|
|
}
|
|
lapd_send_ua(lctx, length, msg->l3h);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
/* save message context for further use */
|
|
memcpy(&dl->lctx, lctx, sizeof(dl->lctx));
|
|
#ifndef TEST_CONTENT_RESOLUTION_NETWORK
|
|
/* send UA response */
|
|
lapd_send_ua(lctx, length, msg->l3h);
|
|
#endif
|
|
/* set Vs, Vr and Va to 0 */
|
|
dl->v_send = dl->v_recv = dl->v_ack = 0;
|
|
/* clear tx_hist */
|
|
lapd_dl_flush_hist(dl);
|
|
/* enter multiple-frame-established state */
|
|
lapd_dl_newstate(dl, LAPD_STATE_MF_EST);
|
|
/* store content resolution data on network side
|
|
* Note: cont_res will be removed when changing state again,
|
|
* so it must be allocated AFTER lapd_dl_newstate(). */
|
|
if (dl->mode == LAPD_MODE_NETWORK && length) {
|
|
dl->cont_res = lapd_msgb_alloc(length, "CONT RES");
|
|
memcpy(msgb_put(dl->cont_res, length), msg->l3h,
|
|
length);
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"Store content res. (dl=%p)\n", dl);
|
|
}
|
|
/* send notification to L3 */
|
|
if (length == 0) {
|
|
/* 5.4.1.2 Normal establishment procedures */
|
|
rc = send_dl_simple(prim, op, lctx);
|
|
msgb_free(msg);
|
|
} else {
|
|
/* 5.4.1.4 Contention resolution establishment */
|
|
msgb_trim(msg, length);
|
|
rc = send_dl_l3(prim, op, lctx, msg);
|
|
}
|
|
break;
|
|
case LAPD_U_DM:
|
|
LOGP(DLLAPD, LOGL_INFO, "DM received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.cmd) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"DM command error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
if (!lctx->p_f) {
|
|
/* 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 LAPD_STATE_SABM_SENT:
|
|
break;
|
|
case LAPD_STATE_MF_EST:
|
|
if (lctx->p_f) {
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited DM "
|
|
"response (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_DM_RESP, lctx);
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited DM "
|
|
"response, multiple frame established "
|
|
"state (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_DM_RESP_MF, lctx);
|
|
/* reestablish */
|
|
if (!dl->reestablish) {
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Performing "
|
|
"reestablishment. (dl=%p)\n", dl);
|
|
lapd_reestablish(dl);
|
|
}
|
|
msgb_free(msg);
|
|
return 0;
|
|
case LAPD_STATE_TIMER_RECOV:
|
|
/* FP = 0 (DM is normal in case PF = 1) */
|
|
if (!lctx->p_f) {
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited DM "
|
|
"response, multiple frame established "
|
|
"state (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_DM_RESP_MF, lctx);
|
|
msgb_free(msg);
|
|
/* reestablish */
|
|
if (!dl->reestablish)
|
|
return 0;
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Performing "
|
|
"reestablishment. (dl=%p)\n", dl);
|
|
return lapd_reestablish(dl);
|
|
}
|
|
break;
|
|
case LAPD_STATE_DISC_SENT:
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* go to idle state */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, lctx);
|
|
msgb_free(msg);
|
|
return 0;
|
|
case LAPD_STATE_IDLE:
|
|
/* 5.4.5 all other frame types shall be discarded */
|
|
default:
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited DM response! "
|
|
"(discarding) (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
/* stop timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* go to idle state */
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION, lctx);
|
|
msgb_free(msg);
|
|
break;
|
|
case LAPD_U_UI:
|
|
LOGP(DLLAPD, LOGL_INFO, "UI received (dl=%p)\n", dl);
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.resp) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "UI indicates response "
|
|
"error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* G.4.5 If UI is received with L>N201 or with M bit
|
|
* set, AN MDL-ERROR-INDICATION is sent to MM.
|
|
*/
|
|
if (length > lctx->n201 || lctx->more) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "UI too large error "
|
|
"(%d > N201(%d) or M=%d) (dl=%p)\n", length,
|
|
lctx->n201, lctx->more, dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx);
|
|
return -EIO;
|
|
}
|
|
|
|
/* do some length checks */
|
|
if (length == 0) {
|
|
/* 5.3.3 UI frames received with the length indicator
|
|
* set to "0" shall be ignored
|
|
*/
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"length=0 (discarding) (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
msgb_trim(msg, length);
|
|
rc = send_dl_l3(PRIM_DL_UNIT_DATA, PRIM_OP_INDICATION, lctx,
|
|
msg);
|
|
break;
|
|
case LAPD_U_DISC:
|
|
prim = PRIM_DL_REL;
|
|
op = PRIM_OP_INDICATION;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "DISC received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* flush tx and send buffers */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
/* 5.7.1 */
|
|
dl->seq_err_cond = 0;
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.resp) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"DISC response error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
if (length > 0 || lctx->more) {
|
|
/* 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(DLLAPD, LOGL_ERROR,
|
|
"U frame iwth incorrect parameters (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx);
|
|
return -EIO;
|
|
}
|
|
switch (dl->state) {
|
|
case LAPD_STATE_IDLE:
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"DISC in idle state (dl=%p)\n", dl);
|
|
/* send DM with F=P */
|
|
msgb_free(msg);
|
|
return lapd_send_dm(lctx);
|
|
case LAPD_STATE_SABM_SENT:
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"DISC in SABM state (dl=%p)\n", dl);
|
|
/* 5.4.6.2 send DM with F=P */
|
|
lapd_send_dm(lctx);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* go to idle state */
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
msgb_free(msg);
|
|
return send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION,
|
|
lctx);
|
|
case LAPD_STATE_MF_EST:
|
|
case LAPD_STATE_TIMER_RECOV:
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"DISC in est state (dl=%p)\n", dl);
|
|
break;
|
|
case LAPD_STATE_DISC_SENT:
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"DISC in disc state (dl=%p)\n", dl);
|
|
prim = PRIM_DL_REL;
|
|
op = PRIM_OP_CONFIRM;
|
|
break;
|
|
default:
|
|
lapd_send_ua(lctx, length, msg->l3h);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
/* send UA response */
|
|
lapd_send_ua(lctx, length, msg->l3h);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* enter idle state, keep tx-buffer with UA response */
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
/* send notification to L3 */
|
|
rc = send_dl_simple(prim, op, lctx);
|
|
msgb_free(msg);
|
|
break;
|
|
case LAPD_U_UA:
|
|
LOGP(DLLAPD, LOGL_INFO, "UA received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.cmd) {
|
|
LOGP(DLLAPD, LOGL_ERROR, "UA indicates command "
|
|
"error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* G.4.5 If UA is received with L>N201 or with M bit
|
|
* set, AN MDL-ERROR-INDICATION is sent to MM.
|
|
*/
|
|
if (lctx->more || length > lctx->n201) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"UA too large error (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx);
|
|
return -EIO;
|
|
}
|
|
|
|
if (!lctx->p_f) {
|
|
/* 5.4.1.2 A UA response with the F bit set to "0"
|
|
* shall be ignored.
|
|
*/
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"F=0 (discarding) (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
switch (dl->state) {
|
|
case LAPD_STATE_SABM_SENT:
|
|
break;
|
|
case LAPD_STATE_MF_EST:
|
|
case LAPD_STATE_TIMER_RECOV:
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited UA response! "
|
|
"(discarding) (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_UA_RESP, lctx);
|
|
msgb_free(msg);
|
|
return 0;
|
|
case LAPD_STATE_DISC_SENT:
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"UA in disconnect state (dl=%p)\n", dl);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* go to idle state */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, lctx);
|
|
msgb_free(msg);
|
|
return 0;
|
|
case LAPD_STATE_IDLE:
|
|
/* 5.4.5 all other frame types shall be discarded */
|
|
default:
|
|
LOGP(DLLAPD, LOGL_INFO, "unsolicited UA response! "
|
|
"(discarding) (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
LOGP(DLLAPD, LOGL_INFO, "UA in SABM state (dl=%p)\n", dl);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* compare UA with SABME if contention resolution is applied */
|
|
if (dl->tx_hist[0].msg->len) {
|
|
if (length != (dl->tx_hist[0].msg->len)
|
|
|| !!memcmp(dl->tx_hist[0].msg->data, msg->l3h,
|
|
length)) {
|
|
LOGP(DLLAPD, LOGL_INFO, "**** UA response "
|
|
"mismatches **** (dl=%p)\n", dl);
|
|
rc = send_dl_simple(PRIM_DL_REL,
|
|
PRIM_OP_INDICATION, lctx);
|
|
msgb_free(msg);
|
|
/* go to idle state */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
return 0;
|
|
}
|
|
}
|
|
/* set Vs, Vr and Va to 0 */
|
|
dl->v_send = dl->v_recv = dl->v_ack = 0;
|
|
/* clear tx_hist */
|
|
lapd_dl_flush_hist(dl);
|
|
/* enter multiple-frame-established state */
|
|
lapd_dl_newstate(dl, LAPD_STATE_MF_EST);
|
|
/* send outstanding frames, if any (resume / reconnect) */
|
|
lapd_send_i(lctx, __LINE__);
|
|
/* send notification to L3 */
|
|
rc = send_dl_simple(PRIM_DL_EST, PRIM_OP_CONFIRM, lctx);
|
|
msgb_free(msg);
|
|
break;
|
|
case LAPD_U_FRMR:
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"Frame reject received (dl=%p)\n", dl);
|
|
/* send MDL ERROR INIDCATION to L3 */
|
|
mdl_error(MDL_CAUSE_FRMR, lctx);
|
|
msgb_free(msg);
|
|
/* reestablish */
|
|
if (!dl->reestablish)
|
|
break;
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"Performing reestablishment. (dl=%p)\n", dl);
|
|
rc = lapd_reestablish(dl);
|
|
break;
|
|
default:
|
|
/* G.3.1 */
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"Unnumbered frame not allowed. (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/* Receive a LAPD S (Supervisory) message from L1 */
|
|
static int lapd_rx_s(struct msgb *msg, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
int length = lctx->length;
|
|
|
|
if (length > 0 || lctx->more) {
|
|
/* 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(DLLAPD, LOGL_ERROR,
|
|
"S frame with incorrect parameters (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_SFRM_INC_PARAM, lctx);
|
|
return -EIO;
|
|
}
|
|
|
|
if (lctx->cr == dl->cr.rem2loc.resp
|
|
&& lctx->p_f
|
|
&& dl->state != LAPD_STATE_TIMER_RECOV) {
|
|
/* 5.4.2.2: Inidcate error on supervisory reponse F=1 */
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"S frame response with F=1 error (dl=%p)\n", dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_SPRV_RESP, lctx);
|
|
}
|
|
|
|
switch (dl->state) {
|
|
case LAPD_STATE_IDLE:
|
|
/* if P=1, respond DM with F=1 (5.2.2) */
|
|
/* 5.4.5 all other frame types shall be discarded */
|
|
if (lctx->p_f)
|
|
lapd_send_dm(lctx); /* F=P */
|
|
/* fall though */
|
|
case LAPD_STATE_SABM_SENT:
|
|
case LAPD_STATE_DISC_SENT:
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"S frame ignored in this state (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
switch (lctx->s_u) {
|
|
case LAPD_S_RR:
|
|
LOGP(DLLAPD, LOGL_INFO, "RR received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */
|
|
lapd_acknowledge(lctx);
|
|
|
|
/* 5.5.3.2 */
|
|
if (lctx->cr == dl->cr.rem2loc.cmd
|
|
&& lctx->p_f) {
|
|
if (!dl->own_busy && !dl->seq_err_cond) {
|
|
LOGP(DLLAPD, LOGL_INFO, "RR frame command "
|
|
"with polling bit set and we are not "
|
|
"busy, so we reply with RR frame "
|
|
"response (dl=%p)\n", dl);
|
|
lapd_send_rr(lctx, 1, 0);
|
|
/* 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(DLLAPD, LOGL_INFO, "RR frame command "
|
|
"with polling bit set and we are busy, "
|
|
"so we reply with RR frame response (dl=%p)\n",
|
|
dl);
|
|
lapd_send_rnr(lctx, 1, 0);
|
|
}
|
|
} else if (lctx->cr == dl->cr.rem2loc.resp
|
|
&& lctx->p_f
|
|
&& dl->state == LAPD_STATE_TIMER_RECOV) {
|
|
LOGP(DLLAPD, LOGL_INFO, "RR response with F==1, "
|
|
"and we are in timer recovery state, so "
|
|
"we leave that state (dl=%p)\n", dl);
|
|
/* V(S) to the N(R) in the RR frame */
|
|
dl->v_send = lctx->n_recv;
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* 5.5.7 Clear timer recovery condition */
|
|
lapd_dl_newstate(dl, LAPD_STATE_MF_EST);
|
|
}
|
|
/* Send message, if possible due to acknowledged data */
|
|
lapd_send_i(lctx, __LINE__);
|
|
|
|
break;
|
|
case LAPD_S_RNR:
|
|
LOGP(DLLAPD, LOGL_INFO, "RNR received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */
|
|
lapd_acknowledge(lctx);
|
|
|
|
/* 5.5.5 */
|
|
/* Set peer receiver busy condition */
|
|
dl->peer_busy = 1;
|
|
|
|
if (lctx->p_f) {
|
|
if (lctx->cr == dl->cr.rem2loc.cmd) {
|
|
if (!dl->own_busy) {
|
|
LOGP(DLLAPD, LOGL_INFO, "RNR poll "
|
|
"command and we are not busy, "
|
|
"so we reply with RR final "
|
|
"response (dl=%p)\n", dl);
|
|
/* Send RR with F=1 */
|
|
lapd_send_rr(lctx, 1, 0);
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO, "RNR poll "
|
|
"command and we are busy, so "
|
|
"we reply with RNR final "
|
|
"response (dl=%p)\n", dl);
|
|
/* Send RNR with F=1 */
|
|
lapd_send_rnr(lctx, 1, 0);
|
|
}
|
|
} else if (dl->state == LAPD_STATE_TIMER_RECOV) {
|
|
LOGP(DLLAPD, LOGL_INFO, "RNR poll response "
|
|
"and we in timer recovery state, so "
|
|
"we leave that state (dl=%p)\n", dl);
|
|
/* 5.5.7 Clear timer recovery condition */
|
|
lapd_dl_newstate(dl, LAPD_STATE_MF_EST);
|
|
/* V(S) to the N(R) in the RNR frame */
|
|
dl->v_send = lctx->n_recv;
|
|
}
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "RNR not polling/final state "
|
|
"received (dl=%p)\n", dl);
|
|
|
|
/* Send message, if possible due to acknowledged data */
|
|
lapd_send_i(lctx, __LINE__);
|
|
|
|
break;
|
|
case LAPD_S_REJ:
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ received in state %s (dl=%p)\n",
|
|
lapd_state_name(dl->state), dl);
|
|
/* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */
|
|
lapd_acknowledge(lctx);
|
|
|
|
/* 5.5.4.1 */
|
|
if (dl->state != LAPD_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 = lctx->n_recv;
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* 5.5.3.2 */
|
|
if (lctx->cr == dl->cr.rem2loc.cmd && lctx->p_f) {
|
|
if (!dl->own_busy && !dl->seq_err_cond) {
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ poll "
|
|
"command not in timer recovery "
|
|
"state and not in own busy "
|
|
"condition received, so we "
|
|
"respond with RR final "
|
|
"response (dl=%p)\n", dl);
|
|
lapd_send_rr(lctx, 1, 0);
|
|
/* 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(DLLAPD, LOGL_INFO, "REJ poll "
|
|
"command not in timer recovery "
|
|
"state and in own busy "
|
|
"condition received, so we "
|
|
"respond with RNR final "
|
|
"response (dl=%p)\n", dl);
|
|
lapd_send_rnr(lctx, 1, 0);
|
|
}
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ response or not "
|
|
"polling command not in timer recovery "
|
|
"state received (dl=%p)\n", dl);
|
|
/* send MDL ERROR INIDCATION to L3 */
|
|
if (lctx->cr == dl->cr.rem2loc.resp && lctx->p_f) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"unsolicited supervisory response! (dl=%p)\n",
|
|
dl);
|
|
mdl_error(MDL_CAUSE_UNSOL_SPRV_RESP, lctx);
|
|
}
|
|
|
|
} else if (lctx->cr == dl->cr.rem2loc.resp && lctx->p_f) {
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ poll response in timer "
|
|
"recovery state received (dl=%p)\n", dl);
|
|
/* 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 = lctx->n_recv;
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* 5.5.7 Clear timer recovery condition */
|
|
lapd_dl_newstate(dl, LAPD_STATE_MF_EST);
|
|
} 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 = lctx->n_recv;
|
|
/* 5.5.3.2 */
|
|
if (lctx->cr == dl->cr.rem2loc.cmd && lctx->p_f) {
|
|
if (!dl->own_busy && !dl->seq_err_cond) {
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ poll "
|
|
"command in timer recovery "
|
|
"state and not in own busy "
|
|
"condition received, so we "
|
|
"respond with RR final "
|
|
"response (dl=%p)\n", dl);
|
|
lapd_send_rr(lctx, 1, 0);
|
|
/* 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(DLLAPD, LOGL_INFO, "REJ poll "
|
|
"command in timer recovery "
|
|
"state and in own busy "
|
|
"condition received, so we "
|
|
"respond with RNR final "
|
|
"response (dl=%p)\n", dl);
|
|
lapd_send_rnr(lctx, 1, 0);
|
|
}
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "REJ response or not "
|
|
"polling command in timer recovery "
|
|
"state received (dl=%p)\n", dl);
|
|
}
|
|
|
|
/* FIXME: 5.5.4.2 2) */
|
|
|
|
/* Send message, if possible due to acknowledged data */
|
|
lapd_send_i(lctx, __LINE__);
|
|
|
|
break;
|
|
default:
|
|
/* G.3.1 */
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"Supervisory frame not allowed. (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
|
|
/* Receive a LAPD I (Information) message from L1 */
|
|
static int lapd_rx_i(struct msgb *msg, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
//uint8_t nr = lctx->n_recv;
|
|
uint8_t ns = lctx->n_send;
|
|
int length = lctx->length;
|
|
int rc;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "I received in state %s on SAPI(%u) (dl=%p)\n",
|
|
lapd_state_name(dl->state), lctx->sapi, dl);
|
|
|
|
/* G.2.2 Wrong value of the C/R bit */
|
|
if (lctx->cr == dl->cr.rem2loc.resp) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"I frame response not allowed (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (length == 0 || length > lctx->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(DLLAPD, LOGL_ERROR,
|
|
"I frame length not allowed (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_IFRM_INC_LEN, lctx);
|
|
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 (lctx->more && length < lctx->n201) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"I frame with M bit too short (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
mdl_error(MDL_CAUSE_IFRM_INC_MBITS, lctx);
|
|
return -EIO;
|
|
}
|
|
|
|
switch (dl->state) {
|
|
case LAPD_STATE_IDLE:
|
|
/* if P=1, respond DM with F=1 (5.2.2) */
|
|
/* 5.4.5 all other frame types shall be discarded */
|
|
if (lctx->p_f)
|
|
lapd_send_dm(lctx); /* F=P */
|
|
/* fall though */
|
|
case LAPD_STATE_SABM_SENT:
|
|
case LAPD_STATE_DISC_SENT:
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"I frame ignored in this state (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
|
|
/* 5.7.1: N(s) sequence error */
|
|
if (ns != dl->v_recv) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "N(S) sequence error: N(S)=%u, "
|
|
"V(R)=%u (dl=%p)\n", ns, dl->v_recv, dl);
|
|
/* discard data */
|
|
msgb_free(msg);
|
|
if (dl->seq_err_cond != 1) {
|
|
/* FIXME: help me understand what exactly todo here
|
|
*/
|
|
dl->seq_err_cond = 1;
|
|
lapd_send_rej(lctx, lctx->p_f);
|
|
} else {
|
|
/* If there are two subsequent sequence errors received,
|
|
* ignore it. (Ignore every second subsequent error.)
|
|
* This happens if our reply with the REJ is too slow,
|
|
* so the remote gets a T200 timeout and sends another
|
|
* frame with a sequence error.
|
|
* Test showed that replying with two subsequent REJ
|
|
* messages could the remote L2 process to abort.
|
|
* Replying too slow shouldn't happen, but may happen
|
|
* over serial link between BB and LAPD.
|
|
*/
|
|
dl->seq_err_cond = 2;
|
|
}
|
|
/* Even if N(s) sequence error, acknowledge to N(R)-1 */
|
|
/* 5.5.3.1: Acknowlege all transmitted frames up the N(R)-1 */
|
|
lapd_acknowledge(lctx); /* V(A) is also set here */
|
|
|
|
/* Send message, if possible due to acknowledged data */
|
|
lapd_send_i(lctx, __LINE__);
|
|
|
|
return 0;
|
|
}
|
|
dl->seq_err_cond = 0;
|
|
|
|
/* Increment receiver state */
|
|
dl->v_recv = inc_mod(dl->v_recv, dl->v_range);
|
|
LOGP(DLLAPD, LOGL_INFO, "incrementing V(R) to %u (dl=%p)\n",
|
|
dl->v_recv, dl);
|
|
|
|
/* 5.5.3.1: Acknowlege all transmitted frames up the the N(R)-1 */
|
|
lapd_acknowledge(lctx); /* 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 (!lctx->more && !dl->rcv_buffer) {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"message in single I frame (dl=%p)\n", dl);
|
|
/* send a DATA INDICATION to L3 */
|
|
msgb_trim(msg, length);
|
|
rc = send_dl_l3(PRIM_DL_DATA, PRIM_OP_INDICATION, lctx,
|
|
msg);
|
|
} else {
|
|
/* create rcv_buffer */
|
|
if (!dl->rcv_buffer) {
|
|
LOGP(DLLAPD, LOGL_INFO, "message in multiple "
|
|
"I frames (first message) (dl=%p)\n", dl);
|
|
dl->rcv_buffer = lapd_msgb_alloc(dl->maxf,
|
|
"LAPD RX");
|
|
dl->rcv_buffer->l3h = dl->rcv_buffer->data;
|
|
}
|
|
/* concat. rcv_buffer */
|
|
if (msgb_l3len(dl->rcv_buffer) + length > dl->maxf) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Received frame "
|
|
"overflow! (dl=%p)\n", dl);
|
|
} else {
|
|
memcpy(msgb_put(dl->rcv_buffer, length),
|
|
msg->l3h, length);
|
|
}
|
|
/* if the last segment was received */
|
|
if (!lctx->more) {
|
|
LOGP(DLLAPD, LOGL_INFO, "message in multiple "
|
|
"I frames (last message) (dl=%p)\n", dl);
|
|
rc = send_dl_l3(PRIM_DL_DATA,
|
|
PRIM_OP_INDICATION, lctx,
|
|
dl->rcv_buffer);
|
|
dl->rcv_buffer = NULL;
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "message in multiple "
|
|
"I frames (next message) (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
|
|
}
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "I frame ignored during own receiver "
|
|
"busy condition\n");
|
|
|
|
/* Check for P bit */
|
|
if (lctx->p_f) {
|
|
/* 5.5.2.1 */
|
|
/* check if we are not in own receiver busy */
|
|
if (!dl->own_busy) {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"we are not busy, send RR (dl=%p)\n", dl);
|
|
/* Send RR with F=1 */
|
|
rc = lapd_send_rr(lctx, 1, 0);
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"we are busy, send RNR (dl=%p)\n", dl);
|
|
/* Send RNR with F=1 */
|
|
rc = lapd_send_rnr(lctx, 1, 0);
|
|
}
|
|
} 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 = lapd_send_i(lctx, __LINE__);
|
|
|
|
/* if update_pending_iframe returns 0 it updated
|
|
* the lapd header of an iframe in the tx queue */
|
|
if (rc && dl->update_pending_frames)
|
|
rc = dl->update_pending_frames(lctx);
|
|
|
|
if (rc) {
|
|
LOGP(DLLAPD, LOGL_INFO, "we are not busy and "
|
|
"have no pending data, send RR (dl=%p)\n",
|
|
dl);
|
|
/* Send RR with F=0 */
|
|
return lapd_send_rr(lctx, 0, 0);
|
|
}
|
|
/* all I or one RR is sent, we are done */
|
|
return 0;
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"we are busy, send RNR (dl=%p)\n", dl);
|
|
/* Send RNR with F=0 */
|
|
rc = lapd_send_rnr(lctx, 0, 0);
|
|
}
|
|
}
|
|
|
|
/* Send message, if possible due to acknowledged data */
|
|
lapd_send_i(lctx, __LINE__);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/* Receive a LAPD message from L1 */
|
|
int lapd_ph_data_ind(struct msgb *msg, struct lapd_msg_ctx *lctx)
|
|
{
|
|
int rc;
|
|
|
|
switch (lctx->format) {
|
|
case LAPD_FORM_U:
|
|
rc = lapd_rx_u(msg, lctx);
|
|
break;
|
|
case LAPD_FORM_S:
|
|
rc = lapd_rx_s(msg, lctx);
|
|
break;
|
|
case LAPD_FORM_I:
|
|
rc = lapd_rx_i(msg, lctx);
|
|
break;
|
|
default:
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"unknown LAPD format (dl=%p)\n", lctx->dl);
|
|
msgb_free(msg);
|
|
rc = -EINVAL;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/* L3 -> L2 */
|
|
|
|
/* send unit data */
|
|
static int lapd_udata_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
memcpy(&nctx, lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = LAPD_U_UI;
|
|
/* keep nctx.p_f */
|
|
nctx.length = msg->len;
|
|
nctx.more = 0;
|
|
|
|
return dl->send_ph_data_req(&nctx, msg);
|
|
}
|
|
|
|
/* request link establishment */
|
|
static int lapd_est_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
if (msg->len)
|
|
LOGP(DLLAPD, LOGL_INFO, "perform establishment with content "
|
|
"(SABM) (dl=%p)\n", dl);
|
|
else
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"perform normal establishm. (SABM), (dl=%p)\n", dl);
|
|
|
|
/* Flush send-queue */
|
|
/* Clear send-buffer */
|
|
lapd_dl_flush_send(dl);
|
|
/* be sure that history is empty */
|
|
lapd_dl_flush_hist(dl);
|
|
|
|
/* save message context for further use */
|
|
memcpy(&dl->lctx, lctx, sizeof(dl->lctx));
|
|
|
|
/* Discard partly received L3 message */
|
|
msgb_free(dl->rcv_buffer);
|
|
dl->rcv_buffer = NULL;
|
|
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM;
|
|
nctx.p_f = 1;
|
|
nctx.length = msg->len;
|
|
nctx.more = 0;
|
|
|
|
/* Transmit-buffer carries exactly one segment */
|
|
dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST");
|
|
msgb_put(dl->tx_hist[0].msg, msg->len);
|
|
if (msg->len)
|
|
memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len);
|
|
dl->tx_hist[0].more = 0;
|
|
/* 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;
|
|
lapd_dl_newstate(dl, LAPD_STATE_SABM_SENT);
|
|
|
|
/* Tramsmit and start T200 */
|
|
dl->send_ph_data_req(&nctx, msg);
|
|
lapd_start_t200(dl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* send data */
|
|
static int lapd_data_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
|
|
if (msgb_l3len(msg) == 0) {
|
|
LOGP(DLLAPD, LOGL_ERROR,
|
|
"writing an empty message is not possible. (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
return -1;
|
|
}
|
|
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"writing message to send-queue: l3len: %d (dl=%p)\n",
|
|
msgb_l3len(msg), dl);
|
|
|
|
/* Write data into the send queue */
|
|
msgb_enqueue(&dl->send_queue, msg);
|
|
|
|
/* Send message, if possible */
|
|
lapd_send_i(&dl->lctx, __LINE__);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Send next I frame from queued/buffered data */
|
|
static int lapd_send_i(struct lapd_msg_ctx *lctx, int line)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
uint8_t k = dl->k;
|
|
uint8_t h;
|
|
struct msgb *msg;
|
|
int length, left;
|
|
int rc = - 1; /* we sent nothing */
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"%s() called from line %d (dl=%p)\n", __func__, line, dl);
|
|
|
|
next_frame:
|
|
|
|
if (dl->peer_busy) {
|
|
LOGP(DLLAPD, LOGL_INFO, "peer busy, not sending (dl=%p)\n", dl);
|
|
return rc;
|
|
}
|
|
|
|
if (dl->state == LAPD_STATE_TIMER_RECOV) {
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"timer recovery, not sending (dl=%p)\n", dl);
|
|
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_mod(dl->v_ack, k, dl->v_range)) {
|
|
LOGP(DLLAPD, LOGL_INFO, "k frames outstanding, not sending "
|
|
"more (k=%u V(S)=%u V(A)=%u) (dl=%p)\n", k, dl->v_send,
|
|
dl->v_ack, dl);
|
|
return rc;
|
|
}
|
|
|
|
h = do_mod(dl->v_send, dl->range_hist);
|
|
|
|
/* if we have no tx_hist yet, we create it */
|
|
if (!dl->tx_hist[h].msg) {
|
|
/* 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(DLLAPD, LOGL_INFO, "get message from "
|
|
"send-queue (dl=%p)\n", dl);
|
|
}
|
|
|
|
/* 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 > lctx->n201)
|
|
length = lctx->n201;
|
|
LOGP(DLLAPD, LOGL_INFO, "msg-len %d sent %d left %d N201 %d "
|
|
"length %d first byte %02x (dl=%p)\n",
|
|
msgb_l3len(dl->send_buffer), dl->send_out, left,
|
|
lctx->n201, length, dl->send_buffer->l3h[0], dl);
|
|
/* If message in send-buffer is completely sent */
|
|
if (left == 0) {
|
|
msgb_free(dl->send_buffer);
|
|
dl->send_buffer = NULL;
|
|
goto next_message;
|
|
}
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "send I frame %sV(S)=%d (dl=%p)\n",
|
|
(left > length) ? "segment " : "", dl->v_send, dl);
|
|
|
|
/* Create I frame (segment) and transmit-buffer content */
|
|
msg = lapd_msgb_alloc(length, "LAPD I");
|
|
msg->l3h = msgb_put(msg, length);
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_I;
|
|
nctx.p_f = 0;
|
|
nctx.n_send = dl->v_send;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = length;
|
|
if (left > length)
|
|
nctx.more = 1;
|
|
else
|
|
nctx.more = 0;
|
|
if (length)
|
|
memcpy(msg->l3h, dl->send_buffer->l3h + dl->send_out,
|
|
length);
|
|
/* store in tx_hist */
|
|
dl->tx_hist[h].msg = lapd_msgb_alloc(msg->len, "HIST");
|
|
msgb_put(dl->tx_hist[h].msg, msg->len);
|
|
if (length)
|
|
memcpy(dl->tx_hist[h].msg->data, msg->l3h, msg->len);
|
|
dl->tx_hist[h].more = nctx.more;
|
|
/* Add length to track how much is already in the tx buffer */
|
|
dl->send_out += length;
|
|
} else {
|
|
LOGP(DLLAPD, LOGL_INFO, "resend I frame from tx buffer "
|
|
"V(S)=%d (dl=%p)\n", dl->v_send, dl);
|
|
|
|
/* Create I frame (segment) from tx_hist */
|
|
length = dl->tx_hist[h].msg->len;
|
|
msg = lapd_msgb_alloc(length, "LAPD I resend");
|
|
msg->l3h = msgb_put(msg, length);
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_I;
|
|
nctx.p_f = 0;
|
|
nctx.n_send = dl->v_send;
|
|
nctx.n_recv = dl->v_recv;
|
|
nctx.length = length;
|
|
nctx.more = dl->tx_hist[h].more;
|
|
if (length)
|
|
memcpy(msg->l3h, dl->tx_hist[h].msg->data, length);
|
|
}
|
|
|
|
/* 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_mod(dl->v_send, dl->v_range);
|
|
|
|
/* 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)) {
|
|
/* stop Timer T203, if running */
|
|
lapd_stop_t203(dl);
|
|
/* start Timer T200 */
|
|
lapd_start_t200(dl);
|
|
}
|
|
|
|
dl->send_ph_data_req(&nctx, msg);
|
|
|
|
rc = 0; /* we sent something */
|
|
goto next_frame;
|
|
}
|
|
|
|
/* request link suspension */
|
|
static int lapd_susp_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "perform suspension (dl=%p)\n", dl);
|
|
|
|
/* put back the send-buffer to the send-queue (first position) */
|
|
if (dl->send_buffer) {
|
|
LOGP(DLLAPD, LOGL_INFO, "put frame in sendbuffer back to "
|
|
"queue (dl=%p)\n", dl);
|
|
llist_add(&dl->send_buffer->list, &dl->send_queue);
|
|
dl->send_buffer = NULL;
|
|
} else
|
|
LOGP(DLLAPD, LOGL_INFO, "no frame in sendbuffer (dl=%p)\n", dl);
|
|
|
|
/* Clear transmit buffer, but keep send buffer */
|
|
lapd_dl_flush_tx(dl);
|
|
/* Stop timers (there is no state change, so we must stop all timers */
|
|
lapd_stop_t200(dl);
|
|
lapd_stop_t203(dl);
|
|
|
|
msgb_free(msg);
|
|
|
|
return send_dl_simple(PRIM_DL_SUSP, PRIM_OP_CONFIRM, &dl->lctx);
|
|
}
|
|
|
|
/* request, resume or reconnect of link */
|
|
static int lapd_res_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
LOGP(DLLAPD, LOGL_INFO,
|
|
"perform re-establishment (SABM) length=%d (dl=%p)\n",
|
|
msg->len, dl);
|
|
|
|
/* be sure that history is empty */
|
|
lapd_dl_flush_hist(dl);
|
|
|
|
/* save message context for further use */
|
|
memcpy(&dl->lctx, lctx, sizeof(dl->lctx));
|
|
|
|
/* Replace message in the send-buffer (reconnect) */
|
|
msgb_free(dl->send_buffer);
|
|
dl->send_buffer = NULL;
|
|
|
|
dl->send_out = 0;
|
|
if (msg->len) {
|
|
/* Write data into the send buffer, to be sent first */
|
|
dl->send_buffer = msg;
|
|
} else {
|
|
msgb_free(msg);
|
|
msg = NULL;
|
|
dl->send_buffer = NULL;
|
|
}
|
|
|
|
/* Discard partly received L3 message */
|
|
msgb_free(dl->rcv_buffer);
|
|
dl->rcv_buffer = NULL;
|
|
|
|
/* Create new msgb (old one is now free) */
|
|
msg = lapd_msgb_alloc(0, "LAPD SABM");
|
|
msg->l3h = msg->data;
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM;
|
|
nctx.p_f = 1;
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST");
|
|
msgb_put(dl->tx_hist[0].msg, msg->len);
|
|
if (msg->len)
|
|
memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len);
|
|
dl->tx_hist[0].more = 0;
|
|
/* 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;
|
|
lapd_dl_newstate(dl, LAPD_STATE_SABM_SENT);
|
|
|
|
/* Tramsmit and start T200 */
|
|
dl->send_ph_data_req(&nctx, msg);
|
|
lapd_start_t200(dl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* requesst release of link */
|
|
static int lapd_rel_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
struct lapd_msg_ctx nctx;
|
|
|
|
/* local release */
|
|
if (dp->u.rel_req.mode) {
|
|
LOGP(DLLAPD, LOGL_INFO, "perform local release (dl=%p)\n", dl);
|
|
msgb_free(msg);
|
|
/* stop Timer T200 */
|
|
lapd_stop_t200(dl);
|
|
/* enter idle state, T203 is stopped here, if running */
|
|
lapd_dl_newstate(dl, LAPD_STATE_IDLE);
|
|
/* flush buffers */
|
|
lapd_dl_flush_tx(dl);
|
|
lapd_dl_flush_send(dl);
|
|
/* send notification to L3 */
|
|
return send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx);
|
|
}
|
|
|
|
/* in case we are already disconnecting */
|
|
if (dl->state == LAPD_STATE_DISC_SENT)
|
|
return -EBUSY;
|
|
|
|
/* flush tx_hist */
|
|
lapd_dl_flush_hist(dl);
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "perform normal release (DISC) (dl=%p)\n", dl);
|
|
|
|
/* Push LAPD header on msgb */
|
|
/* assemble message */
|
|
memcpy(&nctx, &dl->lctx, sizeof(nctx));
|
|
/* keep nctx.ldp */
|
|
/* keep nctx.sapi */
|
|
/* keep nctx.tei */
|
|
nctx.cr = dl->cr.loc2rem.cmd;
|
|
nctx.format = LAPD_FORM_U;
|
|
nctx.s_u = LAPD_U_DISC;
|
|
nctx.p_f = 1;
|
|
nctx.length = 0;
|
|
nctx.more = 0;
|
|
|
|
dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST");
|
|
msgb_put(dl->tx_hist[0].msg, msg->len);
|
|
if (msg->len)
|
|
memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len);
|
|
dl->tx_hist[0].more = 0;
|
|
/* set Vs to 0, because it is used as index when resending DISC */
|
|
dl->v_send = 0;
|
|
|
|
/* Set states */
|
|
dl->own_busy = dl->peer_busy = 0;
|
|
dl->retrans_ctr = 0;
|
|
lapd_dl_newstate(dl, LAPD_STATE_DISC_SENT);
|
|
|
|
/* Tramsmit and start T200 */
|
|
dl->send_ph_data_req(&nctx, msg);
|
|
lapd_start_t200(dl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* request release of link in idle state */
|
|
static int lapd_rel_req_idle(struct osmo_dlsap_prim *dp,
|
|
struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
struct msgb *msg = dp->oph.msg;
|
|
|
|
msgb_free(msg);
|
|
|
|
/* send notification to L3 */
|
|
return send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx);
|
|
}
|
|
|
|
/* statefull handling for DL SAP messages from L3 */
|
|
static const struct l2downstate {
|
|
uint32_t states;
|
|
int prim, op;
|
|
const char *name;
|
|
int (*rout) (struct osmo_dlsap_prim *dp,
|
|
struct lapd_msg_ctx *lctx);
|
|
} l2downstatelist[] = {
|
|
/* create and send UI command */
|
|
{ALL_STATES,
|
|
PRIM_DL_UNIT_DATA, PRIM_OP_REQUEST,
|
|
"DL-UNIT-DATA-REQUEST", lapd_udata_req},
|
|
|
|
/* create and send SABM command */
|
|
{SBIT(LAPD_STATE_IDLE),
|
|
PRIM_DL_EST, PRIM_OP_REQUEST,
|
|
"DL-ESTABLISH-REQUEST", lapd_est_req},
|
|
|
|
/* create and send I command */
|
|
{SBIT(LAPD_STATE_MF_EST) |
|
|
SBIT(LAPD_STATE_TIMER_RECOV),
|
|
PRIM_DL_DATA, PRIM_OP_REQUEST,
|
|
"DL-DATA-REQUEST", lapd_data_req},
|
|
|
|
/* suspend datalink */
|
|
{SBIT(LAPD_STATE_MF_EST) |
|
|
SBIT(LAPD_STATE_TIMER_RECOV),
|
|
PRIM_DL_SUSP, PRIM_OP_REQUEST,
|
|
"DL-SUSPEND-REQUEST", lapd_susp_req},
|
|
|
|
/* create and send SABM command (resume) */
|
|
{SBIT(LAPD_STATE_MF_EST) |
|
|
SBIT(LAPD_STATE_TIMER_RECOV),
|
|
PRIM_DL_RES, PRIM_OP_REQUEST,
|
|
"DL-RESUME-REQUEST", lapd_res_req},
|
|
|
|
/* create and send SABM command (reconnect) */
|
|
{SBIT(LAPD_STATE_IDLE) |
|
|
SBIT(LAPD_STATE_MF_EST) |
|
|
SBIT(LAPD_STATE_TIMER_RECOV),
|
|
PRIM_DL_RECON, PRIM_OP_REQUEST,
|
|
"DL-RECONNECT-REQUEST", lapd_res_req},
|
|
|
|
/* create and send DISC command */
|
|
{SBIT(LAPD_STATE_SABM_SENT) |
|
|
SBIT(LAPD_STATE_MF_EST) |
|
|
SBIT(LAPD_STATE_TIMER_RECOV) |
|
|
SBIT(LAPD_STATE_DISC_SENT),
|
|
PRIM_DL_REL, PRIM_OP_REQUEST,
|
|
"DL-RELEASE-REQUEST", lapd_rel_req},
|
|
|
|
/* release in idle state */
|
|
{SBIT(LAPD_STATE_IDLE),
|
|
PRIM_DL_REL, PRIM_OP_REQUEST,
|
|
"DL-RELEASE-REQUEST", lapd_rel_req_idle},
|
|
};
|
|
|
|
#define L2DOWNSLLEN \
|
|
(sizeof(l2downstatelist) / sizeof(struct l2downstate))
|
|
|
|
int lapd_recv_dlsap(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx)
|
|
{
|
|
struct lapd_datalink *dl = lctx->dl;
|
|
int i, supported = 0;
|
|
struct msgb *msg = dp->oph.msg;
|
|
int rc;
|
|
|
|
/* find function for current state and message */
|
|
for (i = 0; i < L2DOWNSLLEN; i++) {
|
|
if (dp->oph.primitive == l2downstatelist[i].prim
|
|
&& dp->oph.operation == l2downstatelist[i].op) {
|
|
supported = 1;
|
|
if ((SBIT(dl->state) & l2downstatelist[i].states))
|
|
break;
|
|
}
|
|
}
|
|
if (!supported) {
|
|
LOGP(DLLAPD, LOGL_NOTICE,
|
|
"Message %u/%u unsupported. (dl=%p)\n", dp->oph.primitive,
|
|
dp->oph.operation, dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
if (i == L2DOWNSLLEN) {
|
|
LOGP(DLLAPD, LOGL_NOTICE, "Message %u/%u unhandled at this "
|
|
"state %s. (dl=%p)\n", dp->oph.primitive,
|
|
dp->oph.operation, lapd_state_name(dl->state), dl);
|
|
msgb_free(msg);
|
|
return 0;
|
|
}
|
|
|
|
LOGP(DLLAPD, LOGL_INFO, "Message %s received in state %s (dl=%p)\n",
|
|
l2downstatelist[i].name, lapd_state_name(dl->state), dl);
|
|
|
|
rc = l2downstatelist[i].rout(dp, lctx);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*! @} */
|