diff options
Diffstat (limited to 'openbsc/src/gprs')
| -rw-r--r-- | openbsc/src/gprs/gprs_bssgp.c | 537 | ||||
| -rw-r--r-- | openbsc/src/gprs/gprs_ns.c | 644 |
2 files changed, 1181 insertions, 0 deletions
diff --git a/openbsc/src/gprs/gprs_bssgp.c b/openbsc/src/gprs/gprs_bssgp.c new file mode 100644 index 00000000..554738b5 --- /dev/null +++ b/openbsc/src/gprs/gprs_bssgp.c @@ -0,0 +1,537 @@ +/* GPRS BSSGP protocol implementation as per 3GPP TS 08.18 */ + +/* (C) 2009-2010 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. + * + */ + +#include <errno.h> +#include <stdint.h> + +#include <netinet/in.h> + +#include <osmocore/msgb.h> +#include <osmocore/tlv.h> +#include <osmocore/talloc.h> + +#include <openbsc/debug.h> +#include <openbsc/gsm_data.h> +#include <openbsc/gsm_04_08_gprs.h> +#include <openbsc/gprs_bssgp.h> +#include <openbsc/gprs_llc.h> +#include <openbsc/gprs_ns.h> + +/* global pointer to the gsm network data structure */ +/* FIXME: this must go! */ +extern struct gsm_network *bsc_gsmnet; +struct gprs_ns_inst *bssgp_nsi; + +void *bssgp_tall_ctx = NULL; + +/* BSSGP Protocol specific, not implementation specific */ +/* FIXME: This needs to go into libosmocore after finished */ + +/* Chapter 11.3.9 / Table 11.10: Cause coding */ +static const struct value_string bssgp_cause_strings[] = { + { BSSGP_CAUSE_PROC_OVERLOAD, "Processor overload" }, + { BSSGP_CAUSE_EQUIP_FAIL, "Equipment Failure" }, + { BSSGP_CAUSE_TRASIT_NET_FAIL, "Transit netowkr service failure" }, + { BSSGP_CAUSE_CAPA_GREATER_0KPBS,"Transmission capacity modified" }, + { BSSGP_CAUSE_UNKNOWN_MS, "Unknown MS" }, + { BSSGP_CAUSE_UNKNOWN_BVCI, "Unknown BVCI" }, + { BSSGP_CAUSE_CELL_TRAF_CONG, "Cell traffic congestion" }, + { BSSGP_CAUSE_SGSN_CONG, "SGSN congestion" }, + { BSSGP_CAUSE_OML_INTERV, "O&M intervention" }, + { BSSGP_CAUSE_BVCI_BLOCKED, "BVCI blocked" }, + { BSSGP_CAUSE_PFC_CREATE_FAIL, "PFC create failure" }, + { BSSGP_CAUSE_SEM_INCORR_PDU, "Semantically incorrect PDU" }, + { BSSGP_CAUSE_INV_MAND_INF, "Invalid mandatory information" }, + { BSSGP_CAUSE_MISSING_MAND_IE, "Missing mandatory IE" }, + { BSSGP_CAUSE_MISSING_COND_IE, "Missing conditional IE" }, + { BSSGP_CAUSE_UNEXP_COND_IE, "Unexpected conditional IE" }, + { BSSGP_CAUSE_COND_IE_ERR, "Conditional IE error" }, + { BSSGP_CAUSE_PDU_INCOMP_STATE, "PDU incompatible with protocol state" }, + { BSSGP_CAUSE_PROTO_ERR_UNSPEC, "Protocol error - unspecified" }, + { BSSGP_CAUSE_PDU_INCOMP_FEAT, "PDU not compatible with feature set" }, + { 0, NULL }, +}; + +const char *bssgp_cause_str(enum gprs_bssgp_cause cause) +{ + return get_value_string(bssgp_cause_strings, cause); +} + + +/* Our actual implementation */ + +#define BVC_F_BLOCKED 0x0001 + +/* The per-BTS context that we keep on the SGSN side of the BSSGP link */ +struct bssgp_bts_ctx { + struct llist_head list; + + /* parsed RA ID and Cell ID of the remote BTS */ + struct gprs_ra_id ra_id; + uint16_t cell_id; + + /* NSEI and BVCI of underlying Gb link. Together they + * uniquely identify a link to a BTS (5.4.4) */ + uint16_t bvci; + uint16_t nsei; + + uint32_t bvc_state; + + /* we might want to add this as a shortcut later, avoiding the NSVC + * lookup for every packet, similar to a routing cache */ + //struct gprs_nsvc *nsvc; +}; +LLIST_HEAD(bts_ctxts); + +/* Find a BTS Context based on parsed RA ID and Cell ID */ +struct bssgp_bts_ctx *btsctx_by_raid_cid(const struct gprs_ra_id *raid, uint16_t cid) +{ + struct bssgp_bts_ctx *bctx; + + llist_for_each_entry(bctx, &bts_ctxts, list) { + if (!memcmp(&bctx->ra_id, raid, sizeof(bctx->ra_id)) && + bctx->cell_id == cid) + return bctx; + } + return NULL; +} + +/* Find a BTS context based on BVCI+NSEI tuple */ +struct bssgp_bts_ctx *btsctx_by_bvci_nsei(uint16_t bvci, uint16_t nsei) +{ + struct bssgp_bts_ctx *bctx; + + llist_for_each_entry(bctx, &bts_ctxts, list) { + if (bctx->nsei == nsei && bctx->bvci == bvci) + return bctx; + } + return NULL; +} + +struct bssgp_btx_ctx *btsctx_alloc(uint16_t bvci, uint16_t nsei) +{ + struct bssgp_bts_ctx *ctx; + + ctx = talloc_zero(bssgp_tall_ctx, struct bssgp_bts_ctx); + if (!ctx) + return NULL; + ctx->bvci = bvci; + ctx->nsei = nsei; + llist_add(&ctx->list, &bts_ctxts); + + return ctx; +} + +static inline struct msgb *bssgp_msgb_alloc(void) +{ + return msgb_alloc_headroom(4096, 128, "BSSGP"); +} + +/* Transmit a simple response such as BLOCK/UNBLOCK/RESET ACK/NACK */ +static int bssgp_tx_simple_bvci(uint8_t pdu_type, uint16_t nsei, + uint16_t bvci, uint16_t ns_bvci) +{ + struct msgb *msg = bssgp_msgb_alloc(); + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph)); + uint16_t _bvci; + + msgb_nsei(msg) = nsei; + msgb_bvci(msg) = ns_bvci; + + bgph->pdu_type = pdu_type; + _bvci = htons(bvci); + msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci); + + return gprs_ns_sendmsg(bssgp_nsi, msg); +} + +/* Chapter 10.4.5: Flow Control BVC ACK */ +static int bssgp_tx_fc_bvc_ack(uint16_t nsei, uint8_t tag, uint16_t ns_bvci) +{ + struct msgb *msg = bssgp_msgb_alloc(); + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph)); + + msgb_nsei(msg) = nsei; + msgb_bvci(msg) = ns_bvci; + + bgph->pdu_type = BSSGP_PDUT_FLOW_CONTROL_BVC_ACK; + msgb_tvlv_put(msg, BSSGP_IE_TAG, 1, &tag); + + return gprs_ns_sendmsg(bssgp_nsi, msg); +} + +/* Chapter 10.4.14: Status */ +int bssgp_tx_status(uint8_t cause, uint16_t *bvci, struct msgb *orig_msg) +{ + struct msgb *msg = bssgp_msgb_alloc(); + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph)); + + DEBUGPC(DGPRS, "BSSGP: TX STATUS, cause=%s\n", bssgp_cause_str(cause)); + msgb_nsei(msg) = msgb_nsei(orig_msg); + msgb_bvci(msg) = 0; + + bgph->pdu_type = BSSGP_PDUT_STATUS; + msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, &cause); + if (bvci) { + uint16_t _bvci = htons(*bvci); + msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci); + } + if (orig_msg) + msgb_tvlv_put(msg, BSSGP_IE_PDU_IN_ERROR, + msgb_bssgp_len(orig_msg), msgb_bssgph(orig_msg)); + + return gprs_ns_sendmsg(bssgp_nsi, msg); +} + +uint16_t bssgp_parse_cell_id(struct gprs_ra_id *raid, const uint8_t *buf) +{ + /* 6 octets RAC */ + gsm48_parse_ra(raid, buf); + /* 2 octets CID */ + return ntohs(*(uint16_t *) (buf+6)); +} + +/* Chapter 8.4 BVC-Reset Procedure */ +static int bssgp_rx_bvc_reset(struct msgb *msg, struct tlv_parsed *tp, + uint16_t ns_bvci) +{ + struct bssgp_bts_ctx *bctx; + uint16_t nsei = msgb_nsei(msg); + uint16_t bvci; + int rc; + + bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI)); + DEBUGPC(DGPRS, "BVCI=%u, cause=%s\n", bvci, + bssgp_cause_str(*TLVP_VAL(tp, BSSGP_IE_CAUSE))); + + /* look-up or create the BTS context for this BVC */ + bctx = btsctx_by_bvci_nsei(bvci, nsei); + if (!bctx) + bctx = btsctx_alloc(bvci, nsei); + + /* When we receive a BVC-RESET PDU (at least of a PTP BVCI), the BSS + * informs us about its RAC + Cell ID, so we can create a mapping */ + if (bvci != 0 && bvci != 1) { + if (!TLVP_PRESENT(tp, BSSGP_IE_CELL_ID)) { + LOGP(DGPRS, LOGL_ERROR, "BSSGP RESET BVCI=%u " + "missing mandatory IE\n", bvci); + return -EINVAL; + } + /* actually extract RAC / CID */ + bctx->cell_id = bssgp_parse_cell_id(&bctx->ra_id, + TLVP_VAL(tp, BSSGP_IE_CELL_ID)); + LOGP(DGPRS, LOGL_NOTICE, "Cell %u-%u-%u-%u CI %u on BVCI %u\n", + bctx->ra_id.mcc, bctx->ra_id.mnc, bctx->ra_id.lac, + bctx->ra_id.rac, bctx->cell_id, bvci); + } + + /* Acknowledge the RESET to the BTS */ + rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_RESET_ACK, + nsei, bvci, ns_bvci); + return 0; +} + +/* Uplink unit-data */ +static int bssgp_rx_ul_ud(struct msgb *msg) +{ + struct bssgp_ud_hdr *budh = (struct bssgp_ud_hdr *) msgb_bssgph(msg); + int data_len = msgb_bssgp_len(msg) - sizeof(*budh); + struct tlv_parsed tp; + int rc; + + DEBUGP(DGPRS, "BSSGP UL-UD\n"); + + /* extract TLLI and parse TLV IEs */ + msgb_tlli(msg) = ntohl(budh->tlli); + rc = bssgp_tlv_parse(&tp, budh->data, data_len); + + /* Cell ID and LLC_PDU are the only mandatory IE */ + if (!TLVP_PRESENT(&tp, BSSGP_IE_CELL_ID) || + !TLVP_PRESENT(&tp, BSSGP_IE_LLC_PDU)) + return -EIO; + + /* FIXME: lookup bssgp_bts_ctx based on BVCI + NSEI */ + + /* store pointer to LLC header and CELL ID in msgb->cb */ + msgb_llch(msg) = TLVP_VAL(&tp, BSSGP_IE_LLC_PDU); + msgb_bcid(msg) = TLVP_VAL(&tp, BSSGP_IE_CELL_ID); + + return gprs_llc_rcvmsg(msg, &tp); +} + +static int bssgp_rx_suspend(struct msgb *msg) +{ + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_bssgph(msg); + int data_len = msgb_bssgp_len(msg) - sizeof(*bgph); + struct tlv_parsed tp; + int rc; + + DEBUGP(DGPRS, "BSSGP SUSPEND\n"); + + rc = bssgp_tlv_parse(&tp, bgph->data, data_len); + if (rc < 0) + return rc; + + if (!TLVP_PRESENT(&tp, BSSGP_IE_TLLI) || + !TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA)) + return -EIO; + + /* FIXME: pass the SUSPEND request to GMM */ + /* SEND SUSPEND_ACK or SUSPEND_NACK */ +} + +static int bssgp_rx_resume(struct msgb *msg) +{ + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_bssgph(msg); + int data_len = msgb_bssgp_len(msg) - sizeof(*bgph); + struct tlv_parsed tp; + int rc; + + DEBUGP(DGPRS, "BSSGP RESUME\n"); + + rc = bssgp_tlv_parse(&tp, bgph->data, data_len); + if (rc < 0) + return rc; + + if (!TLVP_PRESENT(&tp, BSSGP_IE_TLLI) || + !TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA) || + !TLVP_PRESENT(&tp, BSSGP_IE_SUSPEND_REF_NR)) + return -EIO; + + /* FIXME: pass the RESUME request to GMM */ + /* SEND RESUME_ACK or RESUME_NACK */ +} + +static int bssgp_rx_fc_bvc(struct msgb *msg, struct tlv_parsed *tp) +{ + + DEBUGP(DGPRS, "BSSGP FC BVC\n"); + + if (!TLVP_PRESENT(tp, BSSGP_IE_TAG) || + !TLVP_PRESENT(tp, BSSGP_IE_BVC_BUCKET_SIZE) || + !TLVP_PRESENT(tp, BSSGP_IE_BUCKET_LEAK_RATE) || + !TLVP_PRESENT(tp, BSSGP_IE_BMAX_DEFAULT_MS) || + !TLVP_PRESENT(tp, BSSGP_IE_R_DEFAULT_MS)) + return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); + + /* FIXME: actually implement flow control */ + + /* Send FLOW_CONTROL_BVC_ACK */ + return bssgp_tx_fc_bvc_ack(msgb_nsei(msg), *TLVP_VAL(tp, BSSGP_IE_TAG), + msgb_bvci(msg)); +} + +/* We expect msgb_bssgph() to point to the BSSGP header */ +int gprs_bssgp_rcvmsg(struct msgb *msg) +{ + struct bssgp_normal_hdr *bgph = + (struct bssgp_normal_hdr *) msgb_bssgph(msg); + struct tlv_parsed tp; + uint8_t pdu_type = bgph->pdu_type; + int data_len = msgb_bssgp_len(msg) - sizeof(*bgph); + uint16_t bvci; /* PTP BVCI */ + uint16_t ns_bvci = msgb_bvci(msg); + int rc = 0; + + /* Identifiers from DOWN: NSEI, BVCI (both in msg->cb) */ + + /* UNITDATA BSSGP headers have TLLI in front */ + if (pdu_type != BSSGP_PDUT_UL_UNITDATA && + pdu_type != BSSGP_PDUT_DL_UNITDATA) + rc = bssgp_tlv_parse(&tp, bgph->data, data_len); + + switch (pdu_type) { + case BSSGP_PDUT_UL_UNITDATA: + /* some LLC data from the MS */ + rc = bssgp_rx_ul_ud(msg); + break; + case BSSGP_PDUT_RA_CAPABILITY: + /* BSS requests RA capability or IMSI */ + DEBUGP(DGPRS, "BSSGP RA CAPABILITY UPDATE\n"); + /* FIXME: send RA_CAPA_UPDATE_ACK */ + break; + case BSSGP_PDUT_RADIO_STATUS: + DEBUGP(DGPRS, "BSSGP RADIO STATUS\n"); + /* BSS informs us of some exception */ + /* FIXME: notify GMM */ + break; + case BSSGP_PDUT_SUSPEND: + /* MS wants to suspend */ + rc = bssgp_rx_suspend(msg); + break; + case BSSGP_PDUT_RESUME: + /* MS wants to resume */ + rc = bssgp_rx_resume(msg); + break; + case BSSGP_PDUT_FLUSH_LL: + /* BSS informs MS has moved to one cell to other cell */ + DEBUGP(DGPRS, "BSSGP FLUSH LL\n"); + /* FIXME: notify GMM */ + /* Send FLUSH_LL_ACK */ + break; + case BSSGP_PDUT_LLC_DISCARD: + /* BSS informs that some LLC PDU's have been discarded */ + DEBUGP(DGPRS, "BSSGP LLC DISCARDED\n"); + /* FIXME: notify GMM */ + break; + case BSSGP_PDUT_FLOW_CONTROL_BVC: + /* BSS informs us of available bandwidth in Gb interface */ + rc = bssgp_rx_fc_bvc(msg, &tp); + break; + case BSSGP_PDUT_FLOW_CONTROL_MS: + /* BSS informs us of available bandwidth to one MS */ + DEBUGP(DGPRS, "BSSGP FC MS\n"); + /* FIXME: actually implement flow control */ + /* FIXME: Send FLOW_CONTROL_MS_ACK */ + break; + case BSSGP_PDUT_BVC_BLOCK: + /* BSS tells us that BVC shall be blocked */ + DEBUGP(DGPRS, "BSSGP BVC BLOCK "); + if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI) || + !TLVP_PRESENT(&tp, BSSGP_IE_CAUSE)) + goto err_mand_ie; + bvci = ntohs(*(uint16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI)); + DEBUGPC(DGPRS, "BVCI=%u, cause=%s\n", bvci, + bssgp_cause_str(*TLVP_VAL(&tp, BSSGP_IE_CAUSE))); + /* We always acknowledge the BLOCKing */ + rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_BLOCK_ACK, + msgb_nsei(msg), bvci, ns_bvci); + break; + case BSSGP_PDUT_BVC_UNBLOCK: + /* BSS tells us that BVC shall be unblocked */ + DEBUGP(DGPRS, "BSSGP BVC UNBLOCK "); + if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI)) + goto err_mand_ie; + bvci = ntohs(*(uint16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI)); + DEBUGPC(DGPRS, "BVCI=%u\n", bvci); + /* We always acknowledge the unBLOCKing */ + rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_UNBLOCK_ACK, + msgb_nsei(msg), bvci, ns_bvci); + break; + case BSSGP_PDUT_BVC_RESET: + /* BSS tells us that BVC init is required */ + DEBUGP(DGPRS, "BSSGP BVC RESET "); + if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI) || + !TLVP_PRESENT(&tp, BSSGP_IE_CAUSE)) + goto err_mand_ie; + rc = bssgp_rx_bvc_reset(msg, &tp, ns_bvci); + break; + case BSSGP_PDUT_STATUS: + /* Some exception has occurred */ + /* FIXME: notify GMM */ + case BSSGP_PDUT_DOWNLOAD_BSS_PFC: + case BSSGP_PDUT_CREATE_BSS_PFC_ACK: + case BSSGP_PDUT_CREATE_BSS_PFC_NACK: + case BSSGP_PDUT_MODIFY_BSS_PFC: + case BSSGP_PDUT_DELETE_BSS_PFC_ACK: + DEBUGP(DGPRS, "BSSGP PDU type 0x%02x not [yet] implemented\n", + pdu_type); + break; + /* those only exist in the SGSN -> BSS direction */ + case BSSGP_PDUT_DL_UNITDATA: + case BSSGP_PDUT_PAGING_PS: + case BSSGP_PDUT_PAGING_CS: + case BSSGP_PDUT_RA_CAPA_UPDATE_ACK: + case BSSGP_PDUT_SUSPEND_ACK: + case BSSGP_PDUT_SUSPEND_NACK: + case BSSGP_PDUT_RESUME_ACK: + case BSSGP_PDUT_RESUME_NACK: + case BSSGP_PDUT_FLUSH_LL_ACK: + case BSSGP_PDUT_FLOW_CONTROL_BVC_ACK: + case BSSGP_PDUT_FLOW_CONTROL_MS_ACK: + case BSSGP_PDUT_BVC_BLOCK_ACK: + case BSSGP_PDUT_BVC_UNBLOCK_ACK: + case BSSGP_PDUT_SGSN_INVOKE_TRACE: + DEBUGP(DGPRS, "BSSGP PDU type 0x%02x only exists in DL\n", + pdu_type); + rc = -EINVAL; + break; + default: + DEBUGP(DGPRS, "BSSGP PDU type 0x%02x unknown\n", pdu_type); + break; + } + + return rc; +err_mand_ie: + return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); +} + +/* Entry function from upper level (LLC), asking us to transmit a BSSGP PDU + * to a remote MS (identified by TLLI) at a BTS identified by its BVCI and NSEI */ +int gprs_bssgp_tx_dl_ud(struct msgb *msg) +{ + struct bssgp_bts_ctx *bctx; + struct bssgp_ud_hdr *budh; + uint8_t llc_pdu_tlv_hdr_len = 2; + uint8_t *llc_pdu_tlv, *qos_profile; + uint16_t pdu_lifetime = 1000; /* centi-seconds */ + uint8_t qos_profile_default[3] = { 0x00, 0x00, 0x21 }; + uint16_t msg_len = msg->len; + uint16_t bvci = msgb_bvci(msg); + uint16_t nsei = msgb_nsei(msg); + + /* Identifiers from UP: TLLI, BVCI, NSEI (all in msgb->cb) */ + if (bvci < 2) { + LOGP(DGPRS, LOGL_ERROR, "Cannot send DL-UD to BVCI %u\n", + bvci); + return -EINVAL; + } + + bctx = btsctx_by_bvci_nsei(bvci, nsei); + if (!bctx) + bctx = btsctx_alloc(bvci, nsei); + + if (msg->len > TVLV_MAX_ONEBYTE) + llc_pdu_tlv_hdr_len += 1; + + /* prepend the tag and length of the LLC-PDU TLV */ + llc_pdu_tlv = msgb_push(msg, llc_pdu_tlv_hdr_len); + llc_pdu_tlv[0] = BSSGP_IE_LLC_PDU; + if (llc_pdu_tlv_hdr_len > 2) { + llc_pdu_tlv[1] = msg_len >> 8; + llc_pdu_tlv[2] = msg_len & 0xff; + } else { + llc_pdu_tlv[1] = msg_len & 0x3f; + llc_pdu_tlv[1] |= 0x80; + } + + /* FIXME: optional elements */ + + /* prepend the pdu lifetime */ + pdu_lifetime = htons(pdu_lifetime); + msgb_tvlv_push(msg, BSSGP_IE_PDU_LIFETIME, 2, (uint8_t *)&pdu_lifetime); + + /* prepend the QoS profile, TLLI and pdu type */ + budh = (struct bssgp_ud_hdr *) msgb_push(msg, sizeof(*budh)); + memcpy(budh->qos_profile, qos_profile_default, sizeof(qos_profile_default)); + budh->tlli = htonl(msgb_tlli(msg)); + budh->pdu_type = BSSGP_PDUT_DL_UNITDATA; + + /* Identifiers down: BVCI, NSEI (in msgb->cb) */ + + return gprs_ns_sendmsg(bssgp_nsi, msg); +} diff --git a/openbsc/src/gprs/gprs_ns.c b/openbsc/src/gprs/gprs_ns.c new file mode 100644 index 00000000..3d9bb896 --- /dev/null +++ b/openbsc/src/gprs/gprs_ns.c @@ -0,0 +1,644 @@ +/* GPRS Networks Service (NS) messages on the Gb interfacebvci = msgb_bvci(msg); + * 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05) */ + +/* (C) 2009-2010 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 <stdint.h> + +#include <arpa/inet.h> + +#include <openbsc/gsm_data.h> +#include <osmocore/msgb.h> +#include <osmocore/tlv.h> +#include <osmocore/talloc.h> +#include <osmocore/select.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 }, + }, +}; + +/* Lookup struct gprs_nsvc based on NSVCI */ +static struct gprs_nsvc *nsvc_by_nsvci(struct gprs_ns_inst *nsi, + uint16_t nsvci) +{ + struct gprs_nsvc *nsvc; + llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) { + if (nsvc->nsvci == nsvci) + return nsvc; + } + return NULL; +} + +/* Lookup struct gprs_nsvc based on NSVCI */ +static struct gprs_nsvc *nsvc_by_nsei(struct gprs_ns_inst *nsi, + uint16_t nsei) +{ + struct gprs_nsvc *nsvc; + llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) { + if (nsvc->nsei == nsei) + return nsvc; + } + return NULL; +} + + +/* Lookup struct gprs_nsvc based on remote peer socket addr */ +static struct gprs_nsvc *nsvc_by_rem_addr(struct gprs_ns_inst *nsi, + struct sockaddr_in *sin) +{ + struct gprs_nsvc *nsvc; + llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) { + if (!memcmp(&nsvc->ip.bts_addr, sin, sizeof(*sin))) + return nsvc; + } + return NULL; +} + +static void gprs_ns_timer_cb(void *data); + +static struct gprs_nsvc *nsvc_create(struct gprs_ns_inst *nsi, uint16_t nsvci) +{ + struct gprs_nsvc *nsvc; + + nsvc = talloc_zero(nsi, struct gprs_nsvc); + nsvc->nsvci = nsvci; + /* before RESET procedure: BLOCKED and DEAD */ + nsvc->state = NSE_S_BLOCKED; + nsvc->nsi = nsi; + nsvc->timer.cb = gprs_ns_timer_cb; + nsvc->timer.data = nsvc; + + llist_add(&nsvc->list, &nsi->gprs_nsvcs); + + return nsvc; +} + +/* Section 10.3.2, Table 13 */ +static const struct value_string 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" }, + { 0, NULL } +}; + +const char *gprs_ns_cause_str(enum ns_cause cause) +{ + return get_value_string(ns_cause_str, cause); +} + +static int nsip_sendmsg(struct gprs_nsvc *nsvc, struct msgb *msg); + +static int gprs_ns_tx(struct gprs_nsvc *nsvc, struct msgb *msg) +{ + int ret; + + switch (nsvc->nsi->ll) { + case GPRS_NS_LL_UDP: + ret = nsip_sendmsg(nsvc, msg); + break; + default: + LOGP(DGPRS, LOGL_ERROR, "unsupported NS linklayer %u\n", nsvc->nsi->ll); + msgb_free(msg); + ret = -EIO; + break; + } + return ret; +} + +static int gprs_ns_tx_simple(struct gprs_nsvc *nsvc, uint8_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(nsvc, msg); +} + +static int gprs_ns_tx_reset(struct gprs_nsvc *nsvc, uint8_t cause) +{ + struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "GPRS/NS"); + struct gprs_ns_hdr *nsh; + uint16_t nsvci = htons(nsvc->nsvci); + uint16_t nsei = htons(nsvc->nsei); + + if (!msg) + return -ENOMEM; + + nsh = (struct gprs_ns_hdr *) msgb_put(msg, sizeof(*nsh)); + nsh->pdu_type = NS_PDUT_RESET; + + msgb_tvlv_put(msg, NS_IE_CAUSE, 1, &cause); + msgb_tvlv_put(msg, NS_IE_VCI, 2, (uint8_t *) &nsvci); + msgb_tvlv_put(msg, NS_IE_NSEI, 2, (uint8_t *) &nsei); + + return gprs_ns_tx(nsvc, msg); + +} + +#define NS_ALIVE_RETRIES 10 /* after 3 failed retransmit we declare BTS as dead */ + +static const uint8_t timer_mode_tout[_NSVC_TIMER_NR] = { + [NSVC_TIMER_TNS_RESET] = 60, + [NSVC_TIMER_TNS_ALIVE] = 3, + [NSVC_TIMER_TNS_TEST] = 30, +}; + +static void nsvc_start_timer(struct gprs_nsvc *nsvc, enum nsvc_timer_mode mode) +{ + nsvc->alive_retries = 0; + + if (bsc_timer_pending(&nsvc->timer)) + bsc_del_timer(&nsvc->timer); + + nsvc->timer_mode = mode; + bsc_schedule_timer(&nsvc->timer, timer_mode_tout[mode], 0); +} + +static void gprs_ns_timer_cb(void *data) +{ + struct gprs_nsvc *nsvc = data; + + switch (nsvc->timer_mode) { + case NSVC_TIMER_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, "NSEI=%u Tns-alive expired more then " + "%u times, blocking NS-VC\n", nsvc->nsei, + NS_ALIVE_RETRIES); + /* FIXME: inform higher layers */ + return; + } + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_ALIVE); + break; + case NSVC_TIMER_TNS_TEST: + /* Tns-test case: send NS-ALIVE PDU */ + gprs_ns_tx_simple(nsvc, NS_PDUT_ALIVE); + /* start Tns-alive timer */ + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_ALIVE); + break; + case NSVC_TIMER_TNS_RESET: + /* Chapter 7.3: Re-send the RESET */ + gprs_ns_tx_reset(nsvc, NS_CAUSE_OM_INTERVENTION); + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_RESET); + break; + } +} + +/* 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; + uint16_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, "NSEI=%u Tx NS RESET ACK (NSVCI=%u)\n", + nsvc->nsei, nsvc->nsvci); + + msgb_tvlv_put(msg, NS_IE_VCI, 2, (uint8_t *)&nsvci); + msgb_tvlv_put(msg, NS_IE_NSEI, 2, (uint8_t *)&nsei); + + return gprs_ns_tx(nsvc, msg); +} + +/* Section 9.2.10: transmit side / NS-UNITDATA-REQUEST primitive */ +int gprs_ns_sendmsg(struct gprs_ns_inst *nsi, struct msgb *msg) +{ + struct gprs_nsvc *nsvc; + struct gprs_ns_hdr *nsh; + uint16_t bvci = msgb_bvci(msg); + + nsvc = nsvc_by_nsei(nsi, msgb_nsei(msg)); + if (!nsvc) { + LOGP(DGPRS, LOGL_ERROR, "Unable to resolve NSEI %u " + "to NS-VC!\n", msgb_nsei(msg)); + return -EINVAL; + } + + if (!(nsvc->state & NSE_S_ALIVE)) { + LOGP(DGPRS, LOGL_ERROR, "NSEI=%u is not alive, cannot send\n", + nsvc->nsei); + return -EBUSY; + } + if (nsvc->state & NSE_S_BLOCKED) { + LOGP(DGPRS, LOGL_ERROR, "NSEI=%u is blocked, cannot send\n", + nsvc->nsei); + return -EBUSY; + } + + nsh = (struct gprs_ns_hdr *) msgb_push(msg, sizeof(*nsh) + 3); + if (!nsh) { + LOGP(DGPRS, LOGL_ERROR, "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(nsvc, msg); +} + +/* Section 9.2.10: receive side */ +static int gprs_ns_rx_unitdata(struct gprs_nsvc *nsvc, struct msgb *msg) +{ + struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *)msg->l2h; + uint16_t bvci; + + /* spare octet in data[0] */ + bvci = nsh->data[1] << 8 | nsh->data[2]; + msgb_bssgph(msg) = &nsh->data[3]; + msgb_bvci(msg) = bvci; + + /* call upper layer (BSSGP) */ + return nsvc->nsi->cb(GPRS_NS_EVT_UNIT_DATA, nsvc, msg, bvci); +} + +/* Section 9.2.7 */ +static int gprs_ns_rx_status(struct gprs_nsvc *nsvc, struct msgb *msg) +{ + struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h; + struct tlv_parsed tp; + uint8_t cause; + int rc; + + DEBUGP(DGPRS, "NSEI=%u NS STATUS ", nsvc->nsei); + + 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 gprs_nsvc *nsvc, struct msgb *msg) +{ + struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h; + struct tlv_parsed tp; + uint8_t *cause; + uint16_t *nsvci, *nsei; + int rc; + + 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 */ + LOGP(DGPRS, LOGL_ERROR, "NS RESET Missing mandatory IE\n"); + return -EINVAL; + } + + cause = (uint8_t *) TLVP_VAL(&tp, NS_IE_CAUSE); + nsvci = (uint16_t *) TLVP_VAL(&tp, NS_IE_VCI); + nsei = (uint16_t *) TLVP_VAL(&tp, NS_IE_NSEI); + + DEBUGP(DGPRS, "NSEI=%u NS RESET (NSVCI=%u, cause=%s)\n", + nsvc->nsvci, nsvc->nsei, gprs_ns_cause_str(*cause)); + + nsvc->state = NSE_S_BLOCKED | NSE_S_ALIVE; + nsvc->nsei = ntohs(*nsei); + nsvc->nsvci = ntohs(*nsvci); + + /* mark the NS-VC as blocked and alive */ + /* start the test procedure */ + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_ALIVE); + + return gprs_ns_tx_reset_ack(nsvc); +} + +/* main entry point, here incoming NS frames enter */ +int gprs_ns_rcvmsg(struct gprs_ns_inst *nsi, struct msgb *msg, + struct sockaddr_in *saddr) +{ + struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h; + struct gprs_nsvc *nsvc; + int rc = 0; + + /* look up the NSVC based on source address */ + nsvc = nsvc_by_rem_addr(nsi, saddr); + if (!nsvc) { + /* Only the RESET procedure creates a new NSVC */ + if (nsh->pdu_type != NS_PDUT_RESET) { + LOGP(DGPRS, LOGL_INFO, "Ignoring NS PDU type 0x%0x " + "from %s for non-existing NS-VC\n", + nsh->pdu_type, inet_ntoa(saddr->sin_addr)); + //gprs_ns_tx_reset(nsvc, NS_CAUSE_NSVC_UNKNOWN); + return -EIO; + } + LOGP(DGPRS, LOGL_INFO, "Creating NS-VC for BSS at %s:%u\n", + inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port)); + nsvc = nsvc_create(nsi, 0xffff); + nsvc->ip.bts_addr = *saddr; + } else + msgb_nsei(msg) = nsvc->nsei; + + 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->timer); + /* start Tns-test */ + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_TEST); + if (nsvc->remote_end_is_sgsn) { + /* FIXME: this should be one level higher */ + if (nsvc->state & NSE_S_BLOCKED) + rc = gprs_ns_tx_simple(nsvc, NS_PDUT_UNBLOCK); + } + break; + case NS_PDUT_UNITDATA: + /* actual user data */ + rc = gprs_ns_rx_unitdata(nsvc, msg); + break; + case NS_PDUT_STATUS: + rc = gprs_ns_rx_status(nsvc, msg); + break; + case NS_PDUT_RESET: + rc = gprs_ns_rx_reset(nsvc, msg); + break; + case NS_PDUT_RESET_ACK: + DEBUGP(DGPRS, "NSEI=%u Rx NS RESET ACK\n", nsvc->nsei); + /* mark remote NS-VC as blocked + active */ + nsvc->remote_state = NSE_S_BLOCKED | NSE_S_ALIVE; + if (nsvc->remote_end_is_sgsn) { + /* stop RESET timer */ + bsc_del_timer(&nsvc->timer); + /* send ALIVE PDU */ + rc = gprs_ns_tx_simple(nsvc, NS_PDUT_ALIVE); + nsvc_start_timer(nsvc, NSVC_TIMER_TNS_ALIVE); + /* mark local state as BLOCKED + ALIVE */ + nsvc->state = NSE_S_BLOCKED | NSE_S_ALIVE; + } + break; + case NS_PDUT_UNBLOCK: + /* Section 7.2: unblocking procedure */ + DEBUGP(DGPRS, "NSEI=%u Rx NS UNBLOCK\n", nsvc->nsei); + nsvc->state &= ~NSE_S_BLOCKED; + rc = gprs_ns_tx_simple(nsvc, NS_PDUT_UNBLOCK_ACK); + break; + case NS_PDUT_UNBLOCK_ACK: + DEBUGP(DGPRS, "NSEI=%u Rx NS UNBLOCK ACK\n", nsvc->nsei); + /* mark remote NS-VC as unblocked + active */ + nsvc->remote_state = NSE_S_ALIVE; + if (nsvc->remote_end_is_sgsn) + nsvc->state = NSE_S_ALIVE; + break; + case NS_PDUT_BLOCK: + DEBUGP(DGPRS, "NSEI=%u Rx NS BLOCK\n", nsvc->nsei); + nsvc->state |= NSE_S_BLOCKED; + rc = gprs_ns_tx_simple(nsvc, NS_PDUT_UNBLOCK_ACK); + break; + case NS_PDUT_BLOCK_ACK: + DEBUGP(DGPRS, "NSEI=%u Rx NS BLOCK ACK\n", nsvc->nsei); + /* mark remote NS-VC as blocked + active */ + nsvc->remote_state = NSE_S_BLOCKED | NSE_S_ALIVE; + break; + default: + DEBUGP(DGPRS, "NSEI=%u Rx Unknown NS PDU type 0x%02x\n", + nsvc->nsei, nsh->pdu_type); + rc = -EINVAL; + break; + } + return rc; +} + +struct gprs_ns_inst *gprs_ns_instantiate(gprs_ns_cb_t *cb) +{ + struct gprs_ns_inst *nsi = talloc_zero(tall_bsc_ctx, struct gprs_ns_inst); + + nsi->cb = cb; + INIT_LLIST_HEAD(&nsi->gprs_nsvcs); + + return nsi; +} + +void gprs_ns_destroy(struct gprs_ns_inst *nsi) +{ + /* FIXME: clear all timers */ + + /* recursively free the NSI and all its NSVCs */ + talloc_free(nsi); +} + + +/* NS-over-IP code, according to 3GPP TS 48.016 Chapter 6.2 + * We don't support Size Procedure, Configuration Procedure, ChangeWeight Procedure */ + +/* Read a single NS-over-IP message */ +static struct msgb *read_nsip_msg(struct bsc_fd *bfd, int *error, + struct sockaddr_in *saddr) +{ + struct msgb *msg = msgb_alloc(NS_ALLOC_SIZE, "Abis/IP/GPRS-NS"); + int ret = 0; + socklen_t saddr_len = sizeof(*saddr); + + if (!msg) { + *error = -ENOMEM; + return NULL; + } + + ret = recvfrom(bfd->fd, msg->data, NS_ALLOC_SIZE, 0, + (struct sockaddr *)saddr, &saddr_len); + if (ret < 0) { + LOGP(DGPRS, LOGL_ERROR, "recv error %s during NSIP recv\n", + strerror(errno)); + msgb_free(msg); + *error = ret; + return NULL; + } else if (ret == 0) { + msgb_free(msg); + *error = ret; + return NULL; + } + + msg->l2h = msg->data; + msgb_put(msg, ret); + + return msg; +} + +static int handle_nsip_read(struct bsc_fd *bfd) +{ + int error; + struct sockaddr_in saddr; + struct gprs_ns_inst *nsi = bfd->data; + struct msgb *msg = read_nsip_msg(bfd, &error, &saddr); + + if (!msg) + return error; + + return gprs_ns_rcvmsg(nsi, msg, &saddr); +} + +static int handle_nsip_write(struct bsc_fd *bfd) +{ + /* FIXME: actually send the data here instead of nsip_sendmsg() */ + return -EIO; +} + +int nsip_sendmsg(struct gprs_nsvc *nsvc, struct msgb *msg) +{ + int rc; + struct gprs_ns_inst *nsi = nsvc->nsi; + struct sockaddr_in *daddr = &nsvc->ip.bts_addr; + + rc = sendto(nsi->nsip.fd.fd, msg->data, msg->len, 0, + (struct sockaddr *)daddr, sizeof(*daddr)); + + talloc_free(msg); + + return rc; +} + +/* UDP Port 23000 carries the LLC-in-BSSGP-in-NS protocol stack */ +static int nsip_fd_cb(struct bsc_fd *bfd, unsigned int what) |