ns2: add support for frame relay
Add support for frame relay over dahdi hdlc device.
It's supporting lmi by q933 and supports both
SGSN and BSS.
Change-Id: Id3b49f93d33c271f77cd9c9db03cde6b727a4d30
diff --git a/src/gb/frame_relay.c b/src/gb/frame_relay.c
new file mode 100644
index 0000000..f890209
--- /dev/null
+++ b/src/gb/frame_relay.c
@@ -0,0 +1,966 @@
+/*! \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 {
+ 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;
+
+} __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;
+}
+
+/* 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->tx_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->tx_cb_data, resp);
+}
+
+
+/* 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 are not support for 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];
+
+ /* the network checks the receive sequence number received from
+ * the user equipment against its send sequence counter */
+ 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->active = 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;
+
+ LOGPFRL(link, LOGL_NOTICE, "Link failed\n");
+ link->state = false;
+ if (link->role == FR_ROLE_USER_EQUIPMENT)
+ return;
+
+ llist_for_each_entry(dlc, &link->dlc_list, list) {
+ dlc->active = false;
+ }
+ } else {
+ /* good link */
+ if (link->state)
+ return;
+
+ LOGPFRL(link, LOGL_NOTICE, "Link recovered\n");
+ link->state = true;
+ if (link->role == FR_ROLE_USER_EQUIPMENT)
+ return;
+
+ llist_for_each_entry(dlc, &link->dlc_list, list) {
+ if (!dlc->add && !dlc->del)
+ dlc->active = 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->active = 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->active = 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 (dlc->del)
+ continue;
+
+ dlc = osmo_fr_dlc_alloc(link, dlci);
+ if (!dlc) {
+ LOGPFRL(link, LOGL_ERROR, "Rx STATUS: Could not create DLC %d\n", dlci);
+ }
+ }
+
+ if (pvc->delete) {
+ dlc->del = 1;
+ } else {
+ dlc->add = pvc->new;
+ dlc->active = 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 support for role network\n");
+ return -1;
+ }
+
+ /* check for mandatory IEs */
+ if (!TLVP_PRES_LEN(tp, Q933_IEI_REPORT_TYPE, 1)) {
+ LOGPFRL(link, LOGL_NOTICE, "Rx STATUSL: 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;
+ }
+
+ llist_for_each_entry(dlc, &link->dlc_list, list) {
+ if (dlc->dlci == dlci) {
+ /* dispatch to handler of respective DLC */
+ msg->dst = dlc;
+ return dlc->rx_cb(dlc->rx_cb_data, msg);
+ }
+ }
+
+ 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\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->tx_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);
+
+ 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;
+
+ LOGPFRL(link, LOGL_INFO, "Creating frame relay link with role %s\n", osmo_fr_role_str(role));
+
+ 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;
+ }
+
+ 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_IEI_PVC_STATUS);
+
+ 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;
+}