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libosmocore/src/gb/frame_relay.c

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/*! \file frame_relay.c
* Implement frame relay/PVC by Q.933
*/
/* (C) 2020 Harald Welte <laforge@gnumonks.org>
* (C) 2020 sysmocom - s.f.m.c. GmbH
* Author: Alexander Couzens <lynxis@fe80.eu>
*
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <osmocom/gprs/frame_relay.h>
#include <osmocom/core/endian.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/tdef.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/tlv.h>
#define LOGPFRL(frl, lvl, fmt, args ...) \
LOGP(DFR, lvl, "%s: " fmt, (frl)->name, ## args)
#define DFR DLNS
/* Table 4-2/Q.931 */
enum q931_msgtype {
/* Call establishment message */
Q931_MSGT_ALERTING = 0x01,
Q931_MSGT_CALL_PROCEEDING = 0x02,
Q931_MSGT_CONNECT = 0x07,
Q931_MSGT_CONNECT_ACK = 0x0f,
Q931_MSGT_PROGRESS = 0x03,
Q931_MSGT_SETUP = 0x05,
Q931_MSGT_SETUP_ACK = 0x0d,
/* Call information phase message */
Q931_MSGT_RESUME = 0x26,
Q931_MSGT_RESUME_ACK = 0x2e,
Q931_MSGT_RESUME_REJ = 0x22,
Q931_MSGT_SUSPEND = 0x25,
Q931_MSGT_SUSPEND_ACK = 0x2d,
Q931_MSGT_USER_INFO = 0x20,
/* Call clearing message */
Q931_MSGT_DISCONNECT = 0x45,
Q931_MSGT_RELEASE = 0x4d,
Q931_MSGT_RELEASE_COMPLETE = 0x5a,
Q931_MSGT_RESTART = 0x46,
Q931_MSGT_RESTART_ACK = 0x4e,
/* Miscellaneous messages */
Q931_MSGT_SEGMENT = 0x60,
Q931_MSGT_CONGESTION_CONTROL = 0x79,
Q931_MSGT_IFORMATION = 0x7b,
Q931_MSGT_NOTIFY = 0x6e,
Q931_MSGT_STATUS = 0x7d,
Q931_MSGT_STATUS_ENQUIRY = 0x75,
};
/* Figure A.1/Q.933 Report type information element */
enum q933_type_of_report {
Q933_REPT_FULL_STATUS = 0x00,
Q933_REPT_LINK_INTEGRITY_VERIF = 0x01,
Q933_REPT_SINGLE_PVC_ASYNC_STS = 0x02,
};
/* Q.933 Section A.3 */
enum q933_iei {
Q933_IEI_REPORT_TYPE = 0x51,
Q933_IEI_LINK_INT_VERIF = 0x53,
Q933_IEI_PVC_STATUS = 0x57,
};
/* Q.933 Section A.3.3 */
enum q933_pvc_status {
Q933_PVC_STATUS_DLC_ACTIVE = 0x02,
Q933_PVC_STATUS_DLC_DELETE = 0x04,
Q933_PVC_STATUS_DLC_NEW = 0x08,
};
#define LAPF_UI 0x03 /* UI control word */
#define Q931_PDISC_CC 0x08 /* protocol discriminator */
#define LMI_Q933A_CALLREF 0x00 /* NULL call-ref */
/* LMI DLCI values */
#define LMI_Q933A_DLCI 0 /* Q.933A DLCI */
#define LMI_CISCO_DLCI 1023 /* Cisco DLCI */
/* maximum of supported */
#define MAX_SUPPORTED_PVC 10
/* TODO: add counters since good connection */
/* Message header of the L3 payload of a Q.933 Annex A message */
struct q933_a_hdr {
uint8_t prot_disc;
uint8_t call_ref;
uint8_t msg_type;
} __attribute__((packed));
/* Value part of the Q.933 Annex A.3.3 IE */
struct q933_a_pvc_sts {
#if OSMO_IS_LITTLE_ENDIAN
uint8_t dlci_msb:6,
spare:1,
ext0:1;
uint8_t space1:3,
dlci_lsb:4,
ext1:1;
uint8_t reserved:1,
active:1,
delete:1,
new:1,
spare2:3,
ext2:1;
#elif OSMO_IS_BIG_ENDIAN
/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
uint8_t ext0:1, spare:1, dlci_msb:6;
uint8_t ext1:1, dlci_lsb:4, space1:3;
uint8_t ext2:1, spare2:3, new:1, delete:1, active:1, reserved:1;
#endif
} __attribute__((packed));
/* RX Message: 14 [ 00 01 03 08 00 75 95 01 01 00 03 02 01 00 ] */
/* RX Message: 13 [ 00 01 03 08 00 75 51 01 00 53 02 01 00 ] */
const struct value_string osmo_fr_role_names[] = {
{ FR_ROLE_USER_EQUIPMENT, "USER" },
{ FR_ROLE_NETWORK_EQUIPMENT, "NETWORK" },
{ 0, NULL }
};
/* Table A.4/Q.933 */
struct osmo_tdef fr_tdefs[] = {
{
.T=391,
.default_val = 10,
.min_val = 5,
.max_val = 30,
.desc = "Link integrity verification polling timer",
.unit = OSMO_TDEF_S,
}, {
.T=392,
.default_val = 15,
.min_val = 5,
.max_val = 30,
.desc = "Polling verification timer",
.unit = OSMO_TDEF_S,
},
{}
};
static const struct tlv_definition q933_att_tlvdef = {
.def = {
[Q933_IEI_REPORT_TYPE] = { TLV_TYPE_TLV },
[Q933_IEI_LINK_INT_VERIF] = { TLV_TYPE_TLV },
[Q933_IEI_PVC_STATUS] = { TLV_TYPE_TLV },
},
};
static void check_link_state(struct osmo_fr_link *link, bool valid);
static inline uint16_t q922_to_dlci(const uint8_t *hdr)
{
return ((hdr[0] & 0xFC) << 2) | ((hdr[1] & 0xF0) >> 4);
}
static inline void dlci_to_q922(uint8_t *hdr, uint16_t dlci)
{
hdr[0] = (dlci >> 2) & 0xFC;
hdr[1] = ((dlci << 4) & 0xF0) | 0x01;
}
static void dlc_set_active(struct osmo_fr_dlc *dlc, bool active)
{
if (active == dlc->active)
return;
dlc->active = active;
LOGPFRL(dlc->link, LOGL_NOTICE, "DLCI %u became %s\n", dlc->dlci, active ? "active" : "inactive");
if (dlc->status_cb)
dlc->status_cb(dlc, dlc->cb_data, active);
}
/* allocate a message buffer and put Q.933 Annex A headers (L2 + L3) */
static struct msgb *q933_msgb_alloc(uint16_t dlci, uint8_t prot_disc, uint8_t msg_type)
{
struct msgb *msg = msgb_alloc_headroom(1600+64, 64, "FR Q.933 Tx");
struct q933_a_hdr *qh;
if (!msg)
return NULL;
msg->l1h = msgb_put(msg, 2);
dlci_to_q922(msg->l1h, dlci);
/* LAPF UI control */
msg->l2h = msgb_put(msg, 1);
*msg->l2h = LAPF_UI;
msg->l3h = msgb_put(msg, sizeof(*qh));
qh = (struct q933_a_hdr *) msg->l3h;
qh->prot_disc = prot_disc;
qh->call_ref = LMI_Q933A_CALLREF;
qh->msg_type = msg_type;
return msg;
}
/* obtain the [next] transmit sequence number */
static uint8_t link_get_tx_seq(struct osmo_fr_link *link)
{
/* The {user equipment, network} increments the send sequence
* counter using modulo 256. The value zero is skipped. */
link->last_tx_seq++;
if (link->last_tx_seq == 0)
link->last_tx_seq++;
return link->last_tx_seq;
}
/* Append PVC Status IE according to Q.933 A.3.2 */
static void msgb_put_link_int_verif(struct msgb *msg, struct osmo_fr_link *link)
{
uint8_t link_int_tx[2];
link_int_tx[0] = link_get_tx_seq(link);
link_int_tx[1] = link->last_rx_seq;
msgb_tlv_put(msg, Q933_IEI_LINK_INT_VERIF, 2, link_int_tx);
}
static void dlc_destroy(struct osmo_fr_dlc *dlc)
{
llist_del(&dlc->list);
talloc_free(dlc);
}
/* Append PVC Status IE according to Q.933 A.3.3 */
static void msgb_put_pvc_status(struct msgb *msg, struct osmo_fr_dlc *dlc)
{
uint8_t ie[3];
ie[0] = (dlc->dlci >> 4) & 0x3f;
/* extension bits */
ie[1] = 0x80 | ((dlc->dlci & 0xf) << 3);
/* extension bits */
ie[2] = 0x80;
/* FIXME: validate: this status should be added as long it's not yet acked by the remote */
if (dlc->active)
ie[2] |= Q933_PVC_STATUS_DLC_ACTIVE;
if (dlc->add) {
ie[2] |= Q933_PVC_STATUS_DLC_NEW;
/* we've reported it as new once, reset the status */
}
if (dlc->del) {
ie[2] |= Q933_PVC_STATUS_DLC_DELETE;
/* we've reported it as deleted once, destroy it */
dlc_destroy(dlc);
}
msgb_tlv_put(msg, Q933_IEI_PVC_STATUS, 3, ie);
}
/* Send a Q.933 STATUS ENQUIRY given type over given link */
static int tx_lmi_q933_status_enq(struct osmo_fr_link *link, uint8_t rep_type)
{
struct msgb *resp;
resp = q933_msgb_alloc(0, Q931_PDISC_CC, Q931_MSGT_STATUS_ENQUIRY);
if (!resp)
return -1;
resp->dst = link;
link->expected_rep = rep_type;
/* Table A.2/Q.933 */
msgb_tlv_put(resp, Q933_IEI_REPORT_TYPE, 1, &rep_type);
msgb_put_link_int_verif(resp, link);
return link->tx_cb(link->cb_data, resp);
}
/* Send a Q.933 STATUS of given type over given link */
static int tx_lmi_q933_status(struct osmo_fr_link *link, uint8_t rep_type)
{
struct osmo_fr_dlc *dlc;
struct msgb *resp;
resp = q933_msgb_alloc(0, Q931_PDISC_CC, Q931_MSGT_STATUS);
if (!resp)
return -1;
resp->dst = link;
/* Table A.1/Q.933 */
msgb_tlv_put(resp, Q933_IEI_REPORT_TYPE, 1, &rep_type);
switch (rep_type) {
case Q933_REPT_FULL_STATUS:
msgb_put_link_int_verif(resp, link);
llist_for_each_entry(dlc, &link->dlc_list, list) {
if (dlc->add || dlc->del)
dlc->state_send = true;
msgb_put_pvc_status(resp, dlc);
}
break;
case Q933_REPT_LINK_INTEGRITY_VERIF:
msgb_put_link_int_verif(resp, link);
llist_for_each_entry(dlc, &link->dlc_list, list) {
if (dlc->add || dlc->del) {
msgb_put_pvc_status(resp, dlc);
dlc->state_send = true;
}
}
break;
case Q933_REPT_SINGLE_PVC_ASYNC_STS:
llist_for_each_entry(dlc, &link->dlc_list, list)
msgb_put_pvc_status(resp, dlc);
break;
}
return link->tx_cb(link->cb_data, resp);
}
static void link_set_failed(struct osmo_fr_link *link)
{
struct osmo_fr_dlc *dlc;
LOGPFRL(link, LOGL_NOTICE, "Link failed\n");
link->state = false;
if (link->status_cb)
link->status_cb(link, link->cb_data, link->state);
llist_for_each_entry(dlc, &link->dlc_list, list) {
dlc_set_active(dlc, false);
}
}
/* Q.933 */
static int rx_lmi_q933_status_enq(struct msgb *msg, struct tlv_parsed *tp)
{
struct osmo_fr_link *link = msg->dst;
struct osmo_fr_dlc *dlc;
const uint8_t *link_int_rx;
uint8_t rep_type;
OSMO_ASSERT(link);
if (link->role == FR_ROLE_USER_EQUIPMENT) {
LOGPFRL(link, LOGL_ERROR, "STATUS-ENQ aren't supported in role user\n");
return -1;
}
/* check for mandatory IEs */
if (!TLVP_PRES_LEN(tp, Q933_IEI_REPORT_TYPE, 1) ||
!TLVP_PRES_LEN(tp, Q933_IEI_LINK_INT_VERIF, 2))
return -1;
rep_type = *TLVP_VAL(tp, Q933_IEI_REPORT_TYPE);
link_int_rx = TLVP_VAL(tp, Q933_IEI_LINK_INT_VERIF);
link->last_rx_seq = link_int_rx[0];
/* this is a bit of a hack. Q.933 explicitly forbids either side from ever
* sending a sequence number of '0'. Values start from '1' and are modulo 256,
* but '0' is always skipped. So if the peer is sending us a "last received
* sequence number of '0' it means it has not yet received any packets from us,
* which in turn can only mean that it has just been restarted. Let's treat
* this as "service affecting condition" and notify upper layers. This helps
* particularly in recovering from rapidly re-starting peers, where the Q.933
* nor NS have time to actually detect the connection was lost. Se OS#4974 */
if (link_int_rx[1] == 0) {
link_set_failed(link);
/* the network checks the receive sequence number received from
* the user equipment against its send sequence counter */
} else if (link_int_rx[1] != link->last_tx_seq) {
check_link_state(link, false);
link->err_count++;
} else {
check_link_state(link, true);
/* confirm DLC state changes */
llist_for_each_entry(dlc, &link->dlc_list, list) {
if (!dlc->state_send)
continue;
if (dlc->add) {
dlc_set_active(dlc, link->state);
dlc->add = false;
}
if (dlc->del) {
dlc->del = false;
}
dlc->state_send = false;
}
}
/* The network responds to each STATUS ENQUIRY message with a
* STATUS message and resets the T392 timer */
osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0);
return tx_lmi_q933_status(link, rep_type);
}
/* check if the link become active.
* The link becomes active when enough times a STATUS/STATUS ENQUIRY arrives without any loss.
* Look at the last N393 STATUS/STATUS ENQUIRY PDUs. The link is valid if at least N392
* got received.
* param[in] valid contains the status of the last packet */
static void check_link_state(struct osmo_fr_link *link, bool valid)
{
unsigned int last, i;
unsigned int carry = 0;
struct osmo_fr_dlc *dlc;
link->succeed <<= 1;
if (valid)
link->succeed |= 1;
/* count the bits */
last = link->succeed & ((1 << link->net->n393) - 1);
for (i = 0; i < link->net->n393; i++)
if (last & (1 << i))
carry++;
if (link->net->n393 - carry >= link->net->n392) {
/* failing link */
if (!link->state)
return;
link_set_failed(link);
} else {
/* good link */
if (link->state)
return;
LOGPFRL(link, LOGL_NOTICE, "Link recovered\n");
link->state = true;
if (link->status_cb)
link->status_cb(link, link->cb_data, link->state);
if (link->role == FR_ROLE_USER_EQUIPMENT) {
/* make sure the next STATUS ENQUIRY is for a full
* status report to get the configred DLCs ASAP */
link->polling_count = 0;
/* we must not proceed further below if we're in user role,
* as otherwise link recovery would set all DLCs as active */
return;
}
llist_for_each_entry(dlc, &link->dlc_list, list) {
if (!dlc->add && !dlc->del)
dlc_set_active(dlc, true);
}
}
}
static int validate_pvc_status(struct tlv_parsed *tp, size_t tp_len)
{
size_t i;
uint16_t len = 0;
for (i = 0; i < tp_len; i++) {
if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS))
continue;
/* PVC status can be 2 or 3 bytes. If the PVC is bigger
* ignore this to be compatible to future extensions. */
len = TLVP_LEN(&tp[i], Q933_IEI_PVC_STATUS);
if (len <= 1) {
return -EINVAL;
}
/* FIXME: validate correct flags: are some flags invalid at the same time? */
}
return 0;
}
static int parse_full_pvc_status(struct osmo_fr_link *link, struct tlv_parsed *tp, size_t tp_len)
{
size_t i;
int err = 0;
struct osmo_fr_dlc *dlc, *tmp;
struct q933_a_pvc_sts *pvc;
uint16_t dlci = 0;
uint16_t *dlcis = talloc_zero_array(link, uint16_t, tp_len);
if (!dlcis)
return -ENOMEM;
/* first run validate all PVCs */
err = validate_pvc_status(tp, tp_len);
if (err < 0)
goto out;
for (i = 0; i < tp_len; i++) {
if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS))
continue;
/* parse only 3 byte PVCs */
pvc = (struct q933_a_pvc_sts *) TLVP_VAL_MINLEN(
&tp[i],
Q933_IEI_PVC_STATUS,
sizeof(struct q933_a_pvc_sts));
if (!pvc)
continue;
dlci = ((pvc->dlci_msb & 0x3f) << 4) | (pvc->dlci_lsb & 0xf);
dlcis[i] = dlci;
dlc = osmo_fr_dlc_by_dlci(link, dlci);
if (!dlc) {
dlc = osmo_fr_dlc_alloc(link, dlci);
if (!dlc) {
LOGPFRL(link, LOGL_ERROR, "Could not create DLC %d\n", dlci);
continue;
}
}
/* Figure A.3/Q.933: The delete bit is only applicable for timely notification
* using the optional single PVC asynchronous status report.
* Ignoring the delete. */
dlc->add = pvc->new;
dlc_set_active(dlc, pvc->active);
dlc->del = 0;
}
/* check if all dlc are present in PVC Status */
llist_for_each_entry_safe(dlc, tmp, &link->dlc_list, list) {
bool found = false;
for (i = 0; i < tp_len; i++) {
if (dlcis[i] == dlc->dlci) {
found = true;
break;
}
}
if (!found) {
dlc_set_active(dlc, false);
dlc->del = true;
}
}
return 0;
out:
talloc_free(dlcis);
return err;
}
static int parse_link_pvc_status(struct osmo_fr_link *link, struct tlv_parsed *tp, size_t tp_len)
{
int err;
size_t i;
struct q933_a_pvc_sts *pvc;
struct osmo_fr_dlc *dlc;
uint16_t dlci = 0;
err = validate_pvc_status(tp, tp_len);
if (err < 0)
return err;
for (i = 0; i < tp_len; i++) {
if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS))
continue;
/* parse only 3 byte PVCs */
pvc = (struct q933_a_pvc_sts *) TLVP_VAL_MINLEN(
&tp[i],
Q933_IEI_PVC_STATUS,
sizeof(struct q933_a_pvc_sts));
if (!pvc)
continue;
dlci = ((pvc->dlci_msb & 0x3f) << 4) | (pvc->dlci_lsb & 0xf);
dlc = osmo_fr_dlc_by_dlci(link, dlci);
if (!dlc) {
/* don't create dlc's for the ones which are about to be deleted. */
if (pvc->delete)
continue;
dlc = osmo_fr_dlc_alloc(link, dlci);
if (!dlc) {
LOGPFRL(link, LOGL_ERROR, "Rx STATUS: Could not create DLC %d\n", dlci);
continue;
}
}
if (pvc->delete) {
dlc->del = 1;
} else {
dlc->add = pvc->new;
dlc_set_active(dlc, pvc->active);
dlc->del = 0;
}
}
return 0;
}
static size_t count_pvc_status(struct tlv_parsed *tp, size_t tp_len)
{
size_t i, count = 0;
for (i = 0; i < tp_len; i++) {
if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS))
continue;
count++;
}
return count;
}
static int rx_lmi_q933_status(struct msgb *msg, struct tlv_parsed *tp)
{
struct osmo_fr_link *link = msg->dst;
const uint8_t *link_int_rx;
uint8_t rep_type;
OSMO_ASSERT(link);
if (link->role == FR_ROLE_NETWORK_EQUIPMENT) {
LOGPFRL(link, LOGL_ERROR, "Rx STATUS: STATUS aren't supported in role network\n");
return -1;
}
/* check for mandatory IEs */
if (!TLVP_PRES_LEN(tp, Q933_IEI_REPORT_TYPE, 1)) {
LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Missing TLV Q933 Report Type\n");
return -1;
}
rep_type = *TLVP_VAL(tp, Q933_IEI_REPORT_TYPE);
switch (rep_type) {
case Q933_REPT_FULL_STATUS:
case Q933_REPT_LINK_INTEGRITY_VERIF:
if (rep_type != link->expected_rep) {
LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Unexpected Q933 report type (got 0x%x != exp 0x%x)\n",
rep_type, link->expected_rep);
return -1;
}
if (!TLVP_PRES_LEN(tp, Q933_IEI_LINK_INT_VERIF, 2)) {
LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Missing TLV Q933 Link Integrety Verification\n");
return -1;
}
link_int_rx = TLVP_VAL(tp, Q933_IEI_LINK_INT_VERIF);
link->last_rx_seq = link_int_rx[0];
/* The received receive sequence number is not valid if
* it is not equal to the last transmitted send sequence
* number. Ignore messages containing this error. As a
* result, timer T391 expires and the user then
* increments the error count. */
if (link_int_rx[1] != link->last_tx_seq)
return 0;
break;
case Q933_REPT_SINGLE_PVC_ASYNC_STS:
default:
return -1;
}
check_link_state(link, true);
if (count_pvc_status(tp, MAX_SUPPORTED_PVC + 1) > MAX_SUPPORTED_PVC) {
LOGPFRL(link, LOGL_ERROR, "Rx STATUS: Too many PVC! Only %d are supported!\n", MAX_SUPPORTED_PVC);
}
switch (rep_type) {
case Q933_REPT_FULL_STATUS:
parse_full_pvc_status(link, tp, MAX_SUPPORTED_PVC);
break;
case Q933_REPT_LINK_INTEGRITY_VERIF:
parse_link_pvc_status(link, tp, MAX_SUPPORTED_PVC);
break;
default:
break;
}
/* The network responds to each STATUS ENQUIRY message with a
* STATUS message and resets the T392 timer */
osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0);
return 0;
}
static int rx_lmi_q922(struct msgb *msg)
{
struct osmo_fr_link *link = msg->dst;
struct q933_a_hdr *qh;
/* the + 1 is used to detect more than MAX_SUPPORTED_PVC */
struct tlv_parsed tp[MAX_SUPPORTED_PVC + 1];
uint8_t *lapf;
int rc;
OSMO_ASSERT(link);
if (msgb_l2len(msg) < 1)
return -1;
lapf = msgb_l2(msg);
/* we only support LAPF UI frames */
if (lapf[0] != LAPF_UI)
return -1;
msg->l3h = msg->l2h + 1;
if (msgb_l3len(msg) < 3)
return -1;
qh = (struct q933_a_hdr *) msgb_l3(msg);
if (qh->prot_disc != Q931_PDISC_CC) {
LOGPFRL(link, LOGL_NOTICE,
"Rx unsupported LMI protocol discriminator %u\n", qh->prot_disc);
return -1;
}
rc = tlv_parse2(tp, MAX_SUPPORTED_PVC + 1, &q933_att_tlvdef,
msgb_l3(msg) + sizeof(*qh),
msgb_l3len(msg) - sizeof(*qh), 0, 0);
if (rc < 0) {
LOGPFRL(link, LOGL_NOTICE,
"Failed to parse TLVs in LMI message type %u\n", qh->msg_type);
return rc;
}
switch (qh->msg_type) {
case Q931_MSGT_STATUS_ENQUIRY:
rc = rx_lmi_q933_status_enq(msg, tp);
break;
case Q931_MSGT_STATUS:
rc = rx_lmi_q933_status(msg, tp);
break;
default:
LOGPFRL(link, LOGL_NOTICE,
"Rx unsupported LMI message type %u\n", qh->msg_type);
rc = -1;
break;
}
msgb_free(msg);
return rc;
}
int osmo_fr_rx(struct msgb *msg)
{
int rc = 0;
uint8_t *frh;
uint16_t dlci;
struct osmo_fr_dlc *dlc;
struct osmo_fr_link *link = msg->dst;
OSMO_ASSERT(link);
if (msgb_length(msg) < 2) {
LOGPFRL(link, LOGL_ERROR, "Rx short FR header: %u bytes\n", msgb_length(msg));
rc = -1;
goto out;
}
frh = msg->l1h = msgb_data(msg);
if (frh[0] & 0x01) {
LOGPFRL(link, LOGL_NOTICE, "Rx Unsupported single-byte FR address\n");
rc = -1;
goto out;
}
if ((frh[1] & 0x0f) != 0x01) {
LOGPFRL(link, LOGL_NOTICE, "Rx Unknown second FR octet 0x%02x\n", frh[1]);
rc = -1;
goto out;
}
dlci = q922_to_dlci(frh);
msg->l2h = frh + 2;
switch (dlci) {
case LMI_Q933A_DLCI:
return rx_lmi_q922(msg);
case LMI_CISCO_DLCI:
LOGPFRL(link, LOGL_ERROR, "Rx Unsupported FR DLCI %u\n", dlci);
goto out;
}
if (!link->state) {
LOGPFRL(link, LOGL_NOTICE, "Link is not reliable. Discarding Rx PDU on DLCI %d\n", dlci);
goto out;
}
dlc = osmo_fr_dlc_by_dlci(link, dlci);
if (dlc) {
if (dlc->active) {
/* dispatch to handler of respective DLC */
msg->dst = dlc;
return dlc->rx_cb(dlc->cb_data, msg);
} else {
LOGPFRL(link, LOGL_NOTICE, "DLCI %u not yet active. Discarding Rx PDU\n", dlci);
}
} else {
if (link->unknown_dlc_rx_cb)
return link->unknown_dlc_rx_cb(link->unknown_dlc_rx_cb_data, msg);
else
LOGPFRL(link, LOGL_NOTICE, "DLCI %u doesn't exist. Discarding Rx PDU\n", dlci);
}
out:
msgb_free(msg);
return rc;
}
int osmo_fr_tx_dlc(struct msgb *msg)
{
uint8_t *frh;
struct osmo_fr_dlc *dlc = msg->dst;
struct osmo_fr_link *link = dlc->link;
OSMO_ASSERT(dlc);
OSMO_ASSERT(link);
if (!link->state) {
LOGPFRL(link, LOGL_NOTICE, "Link is not reliable (yet), discarding Tx\n");
msgb_free(msg);
return -1;
}
if (!dlc->active) {
LOGPFRL(link, LOGL_NOTICE, "DLCI %u is not active (yet), discarding Tx\n", dlc->dlci);
msgb_free(msg);
return -1;
}
LOGPFRL(link, LOGL_DEBUG, "DLCI %u is active, sending message\n", dlc->dlci);
if (msgb_headroom(msg) < 2) {
msgb_free(msg);
return -ENOSPC;
}
frh = msgb_push(msg, 2);
dlci_to_q922(frh, dlc->dlci);
msg->dst = link;
return link->tx_cb(link->cb_data, msg);
}
/* Every T391 seconds, the user equipment sends a STATUS ENQUIRY
* message to the network and resets its polling timer (T391). */
static void fr_t391_cb(void *data)
{
struct osmo_fr_link *link = data;
OSMO_ASSERT(link);
if (link->polling_count % link->net->n391 == 0)
tx_lmi_q933_status_enq(link, Q933_REPT_FULL_STATUS);
else
tx_lmi_q933_status_enq(link, Q933_REPT_LINK_INTEGRITY_VERIF);
link->polling_count++;
osmo_timer_schedule(&link->t391, osmo_tdef_get(link->net->T_defs, 391, OSMO_TDEF_S, 10), 0);
}
static void fr_t392_cb(void *data)
{
struct osmo_fr_link *link = data;
OSMO_ASSERT(link);
/* A.5 The network increments the error count .. Non-receipt of
* a STATUS ENQUIRY within T392, which results in restarting
* T392 */
link->err_count++;
check_link_state(link, false);
osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0);
}
/* allocate a frame relay network */
struct osmo_fr_network *osmo_fr_network_alloc(void *ctx)
{
struct osmo_fr_network *net = talloc_zero(ctx, struct osmo_fr_network);
if (!net)
return NULL;
INIT_LLIST_HEAD(&net->links);
net->T_defs = fr_tdefs;
osmo_tdefs_reset(net->T_defs);
net->n391 = 6;
net->n392 = 3;
net->n393 = 4;
return net;
}
void osmo_fr_network_free(struct osmo_fr_network *net)
{
struct osmo_fr_link *link, *tmp;
if (!net)
return;
llist_for_each_entry_safe(link, tmp, &net->links, list) {
osmo_fr_link_free(link);
}
}
/* allocate a frame relay link in a given network */
struct osmo_fr_link *osmo_fr_link_alloc(struct osmo_fr_network *net, enum osmo_fr_role role, const char *name)
{
struct osmo_fr_link *link = talloc_zero(net, struct osmo_fr_link);
if (!link)
return NULL;
link->role = role;
link->net = net;
link->name = talloc_strdup(link, name);
INIT_LLIST_HEAD(&link->dlc_list);
llist_add_tail(&link->list, &net->links);
osmo_timer_setup(&link->t391, fr_t391_cb, link);
osmo_timer_setup(&link->t392, fr_t392_cb, link);
switch (role) {
case FR_ROLE_USER_EQUIPMENT:
osmo_timer_schedule(&link->t391, osmo_tdef_get(link->net->T_defs, 391, OSMO_TDEF_S, 15), 0);
break;
case FR_ROLE_NETWORK_EQUIPMENT:
osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0);
break;
}
LOGPFRL(link, LOGL_INFO, "Creating frame relay link with role %s\n", osmo_fr_role_str(role));
return link;
}
void osmo_fr_link_free(struct osmo_fr_link *link)
{
struct osmo_fr_dlc *dlc, *tmp;
if (!link)
return;
osmo_timer_del(&link->t391);
osmo_timer_del(&link->t392);
llist_for_each_entry_safe(dlc, tmp, &link->dlc_list, list) {
osmo_fr_dlc_free(dlc);
}
llist_del(&link->list);
talloc_free(link);
}
/* allocate a data link connectoin on a given framerelay link */
struct osmo_fr_dlc *osmo_fr_dlc_alloc(struct osmo_fr_link *link, uint16_t dlci)
{
struct osmo_fr_dlc *dlc = talloc_zero(link, struct osmo_fr_dlc);
if (!dlc)
return NULL;
dlc->link = link;
dlc->dlci = dlci;
dlc->active = false;
llist_add_tail(&dlc->list, &link->dlc_list);
dlc->add = true;
tx_lmi_q933_status(link, Q933_REPT_SINGLE_PVC_ASYNC_STS);
return dlc;
}
void osmo_fr_dlc_free(struct osmo_fr_dlc *dlc)
{
llist_del(&dlc->list);
talloc_free(dlc);
}
/* TODO: rework osmo_fr_dlc_alloc/free with handling it's own memory.
* For network role: The dlc have to created by the application (e.g. vty).
* The dlc shouldn't free'd directly. It should be communicated to the
* other side and wait until it's confirmed OR the link go off and free it afterwards.
* For user equpment role: The dlc can be created by the application or the dlc will be created
* by the frame relay because the network is configuring the dlc.
* The dlc shouldn't be free'd. Only the handler should be set to NULL.
*/
struct osmo_fr_dlc *osmo_fr_dlc_by_dlci(struct osmo_fr_link *link, uint16_t dlci)
{
struct osmo_fr_dlc *dlc;
llist_for_each_entry(dlc, &link->dlc_list, list) {
if (dlc->dlci == dlci)
return dlc;
}
return NULL;
}
#include <osmocom/vty/vty.h>
#include <osmocom/vty/tdef_vty.h>
static void fr_dlc_dump_vty(struct vty *vty, const struct osmo_fr_dlc *dlc)
{
vty_out(vty, " FR DLC %05u: %s%s%s%s", dlc->dlci,
dlc->active ? "ACTIVE" : "INACTIVE",
dlc->add ? " ADDED" : "", dlc->del ? " DELETED" : "", VTY_NEWLINE);
}
static void fr_link_dump_vty(struct vty *vty, const struct osmo_fr_link *link)
{
const struct osmo_fr_dlc *dlc;
vty_out(vty, "FR Link '%s': Role %s, LastRxSeq %u, LastTxSeq %u%s",
link->name, link->role == FR_ROLE_USER_EQUIPMENT ? "USER" : "NETWORK",
link->last_rx_seq, link->last_tx_seq, VTY_NEWLINE);
llist_for_each_entry(dlc, &link->dlc_list, list) {
fr_dlc_dump_vty(vty, dlc);
}
}
void osmo_fr_network_dump_vty(struct vty *vty, const struct osmo_fr_network *net)
{
struct osmo_fr_link *link;
vty_out(vty, "FR Network: N391 %u, N392 %u, N393 %u%s",
net->n391, net->n392, net->n393, VTY_NEWLINE);
osmo_tdef_vty_out_all(vty, net->T_defs, " ");
llist_for_each_entry(link, &net->links, list) {
fr_link_dump_vty(vty, link);
}
}
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