| /*! \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); |
| } |
| } |