diff options
author | Holger Hans Peter Freyther <zecke@selfish.org> | 2010-05-14 02:42:15 +0800 |
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committer | Holger Hans Peter Freyther <zecke@selfish.org> | 2010-05-14 02:42:15 +0800 |
commit | 74136415adfd8304581625d3cfd05e35bc2b9d87 (patch) | |
tree | 31952769c9ddfb54d7344c02e822e3cec3a6d80e /openbsc/src/gprs/gprs_bssgp.c | |
parent | 428f2301eb50447c11827abf5c96542067813021 (diff) | |
parent | 60cc6acaffe4009bf829a1d939a9d08e3287107b (diff) |
Merge branch 'master' into on-waves/mgcp
Diffstat (limited to 'openbsc/src/gprs/gprs_bssgp.c')
-rw-r--r-- | openbsc/src/gprs/gprs_bssgp.c | 448 |
1 files changed, 448 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..9fdfd329 --- /dev/null +++ b/openbsc/src/gprs/gprs_bssgp.c @@ -0,0 +1,448 @@ +/* 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> + +void *bssgp_tall_ctx = NULL; + +#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; +}; +static 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_bts_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; +} + +/* 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); +} + +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(DBSSGP, "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(DBSSGP, 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(DBSSGP, 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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "BSSGP RA CAPABILITY UPDATE\n"); + /* FIXME: send RA_CAPA_UPDATE_ACK */ + break; + case BSSGP_PDUT_RADIO_STATUS: + DEBUGP(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "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(DBSSGP, "BSSGP PDU type 0x%02x only exists in DL\n", + pdu_type); + rc = -EINVAL; + break; + default: + DEBUGP(DBSSGP, "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(DBSSGP, 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); +} |