| /* GPRS Networks Service (NS) messages on the Gb interface |
| * 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05) */ |
| |
| /* (C) 2009 by Harald Welte <laforge@gnumonks.org> |
| * |
| * 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. |
| * |
| */ |
| |
| /* Some introduction into NS: NS is used typically on top of frame relay, |
| * but in the ip.access world it is encapsulated in UDP packets. It serves |
| * as an intermediate shim betwen BSSGP and the underlying medium. It doesn't |
| * do much, apart from providing congestion notification and status indication. |
| * |
| * Terms: |
| * NS Network Service |
| * NSVC NS Virtual Connection |
| * NSEI NS Entity Identifier |
| * NSVL NS Virtual Link |
| * NSVLI NS Virtual Link Identifier |
| * BVC BSSGP Virtual Connection |
| * BVCI BSSGP Virtual Connection Identifier |
| * NSVCG NS Virtual Connection Goup |
| * Blocked NS-VC cannot be used for user traffic |
| * Alive Ability of a NS-VC to provide communication |
| * |
| * There can be multiple BSSGP virtual connections over one (group of) NSVC's. BSSGP will |
| * therefore identify the BSSGP virtual connection by a BVCI passed down to NS. |
| * NS then has to firgure out which NSVC's are responsible for this BVCI. |
| * Those mappings are administratively configured. |
| */ |
| |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <sys/types.h> |
| |
| #include <arpa/inet.h> |
| |
| #include <openbsc/gsm_data.h> |
| #include <osmocore/msgb.h> |
| #include <osmocore/tlv.h> |
| #include <osmocore/talloc.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/gprs_ns.h> |
| #include <openbsc/gprs_bssgp.h> |
| |
| #define NS_ALLOC_SIZE 1024 |
| |
| static const struct tlv_definition ns_att_tlvdef = { |
| .def = { |
| [NS_IE_CAUSE] = { TLV_TYPE_TvLV, 0 }, |
| [NS_IE_VCI] = { TLV_TYPE_TvLV, 0 }, |
| [NS_IE_PDU] = { TLV_TYPE_TvLV, 0 }, |
| [NS_IE_BVCI] = { TLV_TYPE_TvLV, 0 }, |
| [NS_IE_NSEI] = { TLV_TYPE_TvLV, 0 }, |
| }, |
| }; |
| |
| #define NSE_S_BLOCKED 0x0001 |
| #define NSE_S_ALIVE 0x0002 |
| |
| struct gprs_nsvc { |
| struct llist_head list; |
| |
| u_int16_t nsei; /* end-to-end significance */ |
| u_int16_t nsvci; /* uniquely identifies NS-VC at SGSN */ |
| |
| u_int32_t state; |
| |
| struct timer_list alive_timer; |
| int timer_is_tns_alive; |
| int alive_retries; |
| |
| union { |
| struct { |
| struct sockaddr_in bts_addr; |
| } ip; |
| }; |
| }; |
| |
| /* FIXME: dynamically search for the matching NSVC */ |
| static struct gprs_nsvc dummy_nsvc = { .state = NSE_S_BLOCKED | NSE_S_ALIVE }; |
| |
| /* Section 10.3.2, Table 13 */ |
| static const char *ns_cause_str[] = { |
| [NS_CAUSE_TRANSIT_FAIL] = "Transit network failure", |
| [NS_CAUSE_OM_INTERVENTION] = "O&M intervention", |
| [NS_CAUSE_EQUIP_FAIL] = "Equipment failure", |
| [NS_CAUSE_NSVC_BLOCKED] = "NS-VC blocked", |
| [NS_CAUSE_NSVC_UNKNOWN] = "NS-VC unknown", |
| [NS_CAUSE_BVCI_UNKNOWN] = "BVCI unknown", |
| [NS_CAUSE_SEM_INCORR_PDU] = "Semantically incorrect PDU", |
| [NS_CAUSE_PDU_INCOMP_PSTATE] = "PDU not compatible with protocol state", |
| [NS_CAUSE_PROTO_ERR_UNSPEC] = "Protocol error, unspecified", |
| [NS_CAUSE_INVAL_ESSENT_IE] = "Invalid essential IE", |
| [NS_CAUSE_MISSING_ESSENT_IE] = "Missing essential IE", |
| }; |
| |
| static const char *gprs_ns_cause_str(enum ns_cause cause) |
| { |
| if (cause >= ARRAY_SIZE(ns_cause_str)) |
| return "undefined"; |
| |
| if (ns_cause_str[cause]) |
| return ns_cause_str[cause]; |
| |
| return "undefined"; |
| } |
| |
| static int gprs_ns_tx(struct msgb *msg, struct gprs_nsvc *nsvc) |
| { |
| return ipac_gprs_send(msg, &nsvc->ip.bts_addr); |
| } |
| |
| static int gprs_ns_tx_simple(struct gprs_nsvc *nsvc, u_int8_t pdu_type) |
| { |
| struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "GPRS/NS"); |
| struct gprs_ns_hdr *nsh; |
| |
| if (!msg) |
| return -ENOMEM; |
| |
| nsh = (struct gprs_ns_hdr *) msgb_put(msg, sizeof(*nsh)); |
| |
| nsh->pdu_type = pdu_type; |
| |
| return gprs_ns_tx(msg, nsvc); |
| } |
| |
| #define NS_TIMER_ALIVE 3, 0 /* after 3 seconds without response, we retry */ |
| #define NS_TIMER_TEST 30, 0 /* every 10 seconds we check if the BTS is still alive */ |
| #define NS_ALIVE_RETRIES 10 /* after 3 failed retransmit we declare BTS as dead */ |
| |
| static void gprs_ns_alive_cb(void *data) |
| { |
| struct gprs_nsvc *nsvc = data; |
| |
| if (nsvc->timer_is_tns_alive) { |
| /* Tns-alive case: we expired without response ! */ |
| nsvc->alive_retries++; |
| if (nsvc->alive_retries > NS_ALIVE_RETRIES) { |
| /* mark as dead and blocked */ |
| nsvc->state = NSE_S_BLOCKED; |
| DEBUGP(DGPRS, "Tns-alive more then %u retries, " |
| " blocking NS-VC\n", NS_ALIVE_RETRIES); |
| /* FIXME: inform higher layers */ |
| return; |
| } |
| } else { |
| /* Tns-test case: send NS-ALIVE PDU */ |
| gprs_ns_tx_simple(nsvc, NS_PDUT_ALIVE); |
| /* start Tns-alive timer */ |
| nsvc->timer_is_tns_alive = 1; |
| } |
| bsc_schedule_timer(&nsvc->alive_timer, NS_TIMER_ALIVE); |
| } |
| |
| /* Section 9.2.6 */ |
| static int gprs_ns_tx_reset_ack(struct gprs_nsvc *nsvc) |
| { |
| struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "GPRS/NS"); |
| struct gprs_ns_hdr *nsh; |
| u_int16_t nsvci, nsei; |
| |
| if (!msg) |
| return -ENOMEM; |
| |
| nsvci = htons(nsvc->nsvci); |
| nsei = htons(nsvc->nsei); |
| |
| nsh = (struct gprs_ns_hdr *) msgb_put(msg, sizeof(*nsh)); |
| |
| nsh->pdu_type = NS_PDUT_RESET_ACK; |
| |
| DEBUGP(DGPRS, "nsvci=%u, nsei=%u\n", nsvc->nsvci, nsvc->nsei); |
| |
| msgb_tvlv_put(msg, NS_IE_VCI, 2, (u_int8_t *)&nsvci); |
| msgb_tvlv_put(msg, NS_IE_NSEI, 2, (u_int8_t *)&nsei); |
| |
| return gprs_ns_tx(msg, nsvc); |
| } |
| |
| /* Section 9.2.10: transmit side */ |
| int gprs_ns_sendmsg(struct gprs_ns_link *link, u_int16_t bvci, |
| struct msgb *msg) |
| { |
| struct gprs_ns_hdr *nsh; |
| struct gprs_nsvc *nsvc = &dummy_nsvc; |
| |
| nsh = (struct gprs_ns_hdr *) msgb_push(msg, sizeof(*nsh) + 3); |
| if (!nsh) { |
| DEBUGP(DGPRS, "Not enough headroom for NS header\n"); |
| return -EIO; |
| } |
| |
| nsh->pdu_type = NS_PDUT_UNITDATA; |
| /* spare octet in data[0] */ |
| nsh->data[1] = bvci >> 8; |
| nsh->data[2] = bvci & 0xff; |
| |
| return gprs_ns_tx(msg, nsvc); |
| } |
| |
| /* Section 9.2.10: receive side */ |
| static int gprs_ns_rx_unitdata(struct msgb *msg) |
| { |
| struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *)msg->l2h; |
| u_int16_t bvci; |
| |
| /* spare octet in data[0] */ |
| bvci = nsh->data[1] << 8 | nsh->data[2]; |
| msg->l3h = &nsh->data[3]; |
| |
| /* call upper layer (BSSGP) */ |
| return gprs_bssgp_rcvmsg(msg, bvci); |
| } |
| |
| /* Section 9.2.7 */ |
| static int gprs_ns_rx_status(struct msgb *msg) |
| { |
| struct gprs_ns_hdr *nsh = msg->l2h; |
| struct tlv_parsed tp; |
| u_int8_t cause; |
| int rc; |
| |
| DEBUGP(DGPRS, "NS STATUS "); |
| |
| rc = tlv_parse(&tp, &ns_att_tlvdef, nsh->data, msgb_l2len(msg), 0, 0); |
| |
| if (!TLVP_PRESENT(&tp, NS_IE_CAUSE)) { |
| DEBUGPC(DGPRS, "missing cause IE\n"); |
| return -EINVAL; |
| } |
| |
| cause = *TLVP_VAL(&tp, NS_IE_CAUSE); |
| DEBUGPC(DGPRS, "cause=%s\n", gprs_ns_cause_str(cause)); |
| |
| return 0; |
| } |
| |
| /* Section 7.3 */ |
| static int gprs_ns_rx_reset(struct msgb *msg) |
| { |
| struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h; |
| struct gprs_nsvc *nsvc = &dummy_nsvc; |
| struct tlv_parsed tp; |
| u_int8_t *cause; |
| u_int16_t *nsvci, *nsei; |
| int rc; |
| |
| DEBUGP(DGPRS, "NS RESET "); |
| |
| rc = tlv_parse(&tp, &ns_att_tlvdef, nsh->data, msgb_l2len(msg), 0, 0); |
| |
| if (!TLVP_PRESENT(&tp, NS_IE_CAUSE) || |
| !TLVP_PRESENT(&tp, NS_IE_VCI) || |
| !TLVP_PRESENT(&tp, NS_IE_NSEI)) { |
| /* FIXME: respond with NS_CAUSE_MISSING_ESSENT_IE */ |
| DEBUGPC(DGPRS, "Missing mandatory IE\n"); |
| return -EINVAL; |
| } |
| |
| cause = (u_int8_t *) TLVP_VAL(&tp, NS_IE_CAUSE); |
| nsvci = (u_int16_t *) TLVP_VAL(&tp, NS_IE_VCI); |
| nsei = (u_int16_t *) TLVP_VAL(&tp, NS_IE_NSEI); |
| |
| nsvc->state = NSE_S_BLOCKED | NSE_S_ALIVE; |
| nsvc->nsei = ntohs(*nsei); |
| nsvc->nsvci = ntohs(*nsvci); |
| |
| DEBUGPC(DGPRS, "cause=%s, NSVCI=%u, NSEI=%u\n", |
| gprs_ns_cause_str(*cause), nsvc->nsvci, nsvc->nsei); |
| |
| /* mark the NS-VC as blocked and alive */ |
| /* start the test procedure */ |
| nsvc->alive_timer.cb = gprs_ns_alive_cb; |
| nsvc->alive_timer.data = nsvc; |
| bsc_schedule_timer(&nsvc->alive_timer, NS_TIMER_ALIVE); |
| |
| return gprs_ns_tx_reset_ack(nsvc); |
| } |
| |
| /* main entry point, here incoming NS frames enter */ |
| int gprs_ns_rcvmsg(struct msgb *msg, struct sockaddr_in *saddr) |
| { |
| struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h; |
| struct gprs_nsvc *nsvc = &dummy_nsvc; |
| int rc = 0; |
| |
| /* FIXME: do this properly! */ |
| nsvc->ip.bts_addr = *saddr; |
| |
| switch (nsh->pdu_type) { |
| case NS_PDUT_ALIVE: |
| /* remote end inquires whether we're still alive, |
| * we need to respond with ALIVE_ACK */ |
| rc = gprs_ns_tx_simple(nsvc, NS_PDUT_ALIVE_ACK); |
| break; |
| case NS_PDUT_ALIVE_ACK: |
| /* stop Tns-alive */ |
| bsc_del_timer(&nsvc->alive_timer); |
| /* start Tns-test */ |
| nsvc->timer_is_tns_alive = 0; |
| bsc_schedule_timer(&nsvc->alive_timer, NS_TIMER_TEST); |
| break; |
| case NS_PDUT_UNITDATA: |
| /* actual user data */ |
| rc = gprs_ns_rx_unitdata(msg); |
| break; |
| case NS_PDUT_STATUS: |
| rc = gprs_ns_rx_status(msg); |
| break; |
| case NS_PDUT_RESET: |
| rc = gprs_ns_rx_reset(msg); |
| break; |
| case NS_PDUT_RESET_ACK: |
| /* FIXME: mark remote NS-VC as blocked + active */ |
| break; |
| case NS_PDUT_UNBLOCK: |
| /* Section 7.2: unblocking procedure */ |
| DEBUGP(DGPRS, "NS UNBLOCK\n"); |
| nsvc->state &= ~NSE_S_BLOCKED; |
| rc = gprs_ns_tx_simple(nsvc, NS_PDUT_UNBLOCK_ACK); |
| break; |
| case NS_PDUT_UNBLOCK_ACK: |
| /* FIXME: mark remote NS-VC as unblocked + active */ |
| break; |
| case NS_PDUT_BLOCK: |
| DEBUGP(DGPRS, "NS BLOCK\n"); |
| nsvc->state |= NSE_S_BLOCKED; |
| rc = gprs_ns_tx_simple(nsvc, NS_PDUT_UNBLOCK_ACK); |
| break; |
| case NS_PDUT_BLOCK_ACK: |
| /* FIXME: mark remote NS-VC as blocked + active */ |
| break; |
| default: |
| DEBUGP(DGPRS, "Unknown NS PDU type 0x%02x\n", nsh->pdu_type); |
| rc = -EINVAL; |
| break; |
| } |
| return rc; |
| } |
| |