From 6752fa43b6cdcc2cb33d04b5e6cf3c87c609de68 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Sun, 2 May 2010 09:23:16 +0200 Subject: [gprs] introduce BSSGP concept of BTS contextx A BTS context represents the mapping betewen (RA-ID, Cell-ID) and (BVCI, NSEI) as well as the per-BVC local state. --- openbsc/src/gprs_bssgp.c | 133 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 110 insertions(+), 23 deletions(-) diff --git a/openbsc/src/gprs_bssgp.c b/openbsc/src/gprs_bssgp.c index ab6d1a09..44e0a35c 100644 --- a/openbsc/src/gprs_bssgp.c +++ b/openbsc/src/gprs_bssgp.c @@ -1,6 +1,6 @@ /* GPRS BSSGP protocol implementation as per 3GPP TS 08.18 */ -/* (C) 2009 by Harald Welte +/* (C) 2009-2010 by Harald Welte * * All Rights Reserved * @@ -27,6 +27,8 @@ #include #include +#include + #include #include #include @@ -39,6 +41,8 @@ extern struct gsm_network *bsc_gsmnet; struct gprs_ns_inst *bssgp_nsi; +void *bssgp_tall_ctx = NULL; + /* Chapter 11.3.9 / Table 11.10: Cause coding */ static const char *bssgp_cause_strings[] = { [BSSGP_CAUSE_PROC_OVERLOAD] = "Processor overload", @@ -74,6 +78,68 @@ static const char *bssgp_cause_str(enum gprs_bssgp_cause cause) return "undefined"; } +#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"); @@ -138,22 +204,52 @@ int bssgp_tx_status(u_int8_t cause, u_int16_t *bvci, struct msgb *orig_msg) return gprs_ns_sendmsg(bssgp_nsi, msg); } +static void bssgp_parse_cell_id(struct gprs_ra_id *raid, uint16_t *cid, + const uint8_t *buf) +{ + /* 6 octets RAC */ + gsm48_parse_ra(raid, buf); + /* 2 octets CID */ + *cid = 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) { - uint8_t bvci; + struct bssgp_bts_ctx *bctx; + uint16_t nsei = msgb_nsei(msg); + uint16_t bvci; int rc; bvci = ntohs(*(u_int16_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 */ + bssgp_parse_cell_id(&bctx->ra_id, &bctx->cell_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, - msgb_nsei(msg), bvci, ns_bvci); + nsei, bvci, ns_bvci); return 0; } @@ -161,13 +257,13 @@ static int bssgp_rx_bvc_reset(struct msgb *msg, struct tlv_parsed *tp, static int bssgp_rx_ul_ud(struct msgb *msg, u_int16_t bvci) { struct bssgp_ud_hdr *budh = (struct bssgp_ud_hdr *) msg->l3h; - struct gsm_bts *bts; int data_len = msgb_l3len(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); @@ -176,15 +272,6 @@ static int bssgp_rx_ul_ud(struct msgb *msg, u_int16_t bvci) !TLVP_PRESENT(&tp, BSSGP_IE_LLC_PDU)) return -EIO; -#if 0 //FIXME - /* Determine the BTS based on the Cell ID */ - bts = gsm48_bts_by_ra_id(bsc_gsmnet, - TLVP_VAL(&tp, BSSGP_IE_CELL_ID), - TLVP_LEN(&tp, BSSGP_IE_CELL_ID)); -#endif - if (bts) - msg->trx = bts->c0; - msgb_llch(msg) = TLVP_VAL(&tp, BSSGP_IE_LLC_PDU); return gprs_llc_rcvmsg(msg, &tp); @@ -261,6 +348,7 @@ int gprs_bssgp_rcvmsg(struct msgb *msg, u_int16_t ns_bvci) u_int16_t bvci; int rc = 0; + /* 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); @@ -314,6 +402,7 @@ int gprs_bssgp_rcvmsg(struct msgb *msg, u_int16_t ns_bvci) bvci = ntohs(*(u_int16_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; @@ -324,6 +413,7 @@ int gprs_bssgp_rcvmsg(struct msgb *msg, u_int16_t ns_bvci) goto err_mand_ie; bvci = ntohs(*(u_int16_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; @@ -374,9 +464,11 @@ err_mand_ie: return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); } -int gprs_bssgp_tx_dl_ud(struct msgb *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 RAC and CID */ +int gprs_bssgp_tx_dl_ud(struct msgb *msg, const struct gprs_ra_id *raid, uint16_t cid) { - struct gsm_bts *bts; + struct bssgp_bts_ctx *bctx; struct bssgp_ud_hdr *budh; u_int8_t llc_pdu_tlv_hdr_len = 2; u_int8_t *llc_pdu_tlv, *qos_profile; @@ -384,12 +476,7 @@ int gprs_bssgp_tx_dl_ud(struct msgb *msg) u_int8_t qos_profile_default[3] = { 0x00, 0x00, 0x21 }; u_int16_t msg_len = msg->len; - if (!msg->trx) { - DEBUGP(DGPRS, "Cannot transmit DL-UD without TRX assigned\n"); - return -EINVAL; - } - - bts = msg->trx->bts; + bctx = btsctx_by_raid_cid(raid, cid); if (msg->len > TVLV_MAX_ONEBYTE) llc_pdu_tlv_hdr_len += 1; @@ -417,8 +504,8 @@ int gprs_bssgp_tx_dl_ud(struct msgb *msg) budh->tlli = htonl(msgb_tlli(msg)); budh->pdu_type = BSSGP_PDUT_DL_UNITDATA; - msgb_nsei(msg) = bts->gprs.nse.nsei; - msgb_bvci(msg) = bts->gprs.cell.bvci; + msgb_nsei(msg) = bctx->nsei; + msgb_bvci(msg) = bctx->bvci; return gprs_ns_sendmsg(bssgp_nsi, msg); } -- cgit v1.2.3