cellular-infrastructure
/
osmo-bsc
mirror of https://gerrit.osmocom.org/osmo-bsc
9
0
Fork 0
Code Issues Releases Wiki Activity

[GPRS] LLC: Improve implementation compliance to spec 

Don't allocate a LLC Entity just because BSSGP passes any random
SAPI/TLLI up to us.  We can only do this for XID and UI frames
of the GMM SAPI.

Furthermore, add more comments and debug messages.
This commit is contained in:
Harald Welte 2010-05-13 19:22:55 +02:00
parent e15ad48a82
commit 1ae09c7bd6
2 changed files with 78 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
openbsc/include/openbsc/gprs_llc.h
View File

@ -26,7 +26,43 @@ enum gprs_llc_u_cmd {
GPRS_LLC_U_NULL_CMD = 0x00,
};
/* TS 04.64 Section 7.1.2 Table 7: LLC layer primitives (GMM/SNDCP/SMS/TOM) */
/* TS 04.65 Section 5.1.2 Table 2: Service primitives used by SNDCP */
enum gprs_llc_primitive {
/* GMM <-> LLME */
LLGMM_ASSIGN_REQ, /* GMM tells us new TLLI: TLLI old, TLLI new, Kc, CiphAlg */
LLGMM_RESET_REQ, /* GMM tells us to perform XID negotiation: TLLI */
LLGMM_RESET_CNF, /* LLC informs GMM that XID has completed: TLLI */
LLGMM_SUSPEND_REQ, /* GMM tells us MS has suspended: TLLI, Page */
LLGMM_RESUME_REQ, /* GMM tells us MS has resumed: TLLI */
LLGMM_PAGE_IND, /* LLC asks GMM to page MS: TLLI */
LLGMM_IOV_REQ, /* GMM tells us to perform XID: TLLI */
LLGMM_STATUS_IND, /* LLC informs GMM about error: TLLI, Cause */
/* LLE <-> (GMM/SNDCP/SMS/TOM) */
LL_RESET_IND, /* TLLI */
LL_ESTABLISH_REQ, /* TLLI, XID Req */
LL_ESTABLISH_IND, /* TLLI, XID Req, N201-I, N201-U */
LL_ESTABLISH_RESP, /* TLLI, XID Negotiated */
LL_ESTABLISH_CONF, /* TLLI, XID Neg, N201-i, N201-U */
LL_RELEASE_REQ, /* TLLI, Local */
LL_RELEASE_IND, /* TLLI, Cause */
LL_RELEASE_CONF, /* TLLI */
LL_XID_REQ, /* TLLI, XID Requested */
LL_XID_IND, /* TLLI, XID Req, N201-I, N201-U */
LL_XID_RESP, /* TLLI, XID Negotiated */
LL_XID_CONF, /* TLLI, XID Neg, N201-I, N201-U */
LL_DATA_REQ, /* TLLI, SN-PDU, Ref, QoS, Radio Prio, Ciph */
LL_DATA_IND, /* TLLI, SN-PDU */
LL_DATA_CONF, /* TLLI, Ref */
LL_UNITDATA_REQ, /* TLLI, SN-PDU, Ref, QoS, Radio Prio, Ciph */
LL_UNITDATA_IND, /* TLLI, SN-PDU */
LL_STATUS_IND, /* TLLI, Cause */
};
/* BSSGP-UL-UNITDATA.ind */
int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv);
/* LL-UNITDATA.req */
int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command);
#endif

55
openbsc/src/gprs/gprs_llc.c
View File

@ -111,6 +111,7 @@ enum gprs_llc_cmd {
GPRS_LLC_SABM,
GPRS_LLC_FRMR,
GPRS_LLC_XID,
GPRS_LLC_UI,
};
struct gprs_llc_hdr_parsed {
@ -156,13 +157,13 @@ static void t200_expired(void *data)
switch (lle->state) {
case GPRS_LLS_LOCAL_EST:
/* retransmit SABM */
/* re-start T200 */
/* FIXME: retransmit SABM */
/* FIXME: re-start T200 */
lle->retrans_ctr++;
break;
case GPRS_LLS_LOCAL_REL:
/* retransmit DISC */
/* re-start T200 */
/* FIXME: retransmit DISC */
/* FIXME: re-start T200 */
lle->retrans_ctr++;
break;
}
@ -174,8 +175,8 @@ static void t201_expired(void *data)
struct gprs_llc_lle *lle = data;
if (lle->retrans_ctr < lle->n200) {
/* transmit apropriate supervisory frame (8.6.4.1) */
/* set timer T201 */
/* FIXME: transmit apropriate supervisory frame (8.6.4.1) */
/* FIXME: set timer T201 */
lle->retrans_ctr++;
}
}
@ -213,6 +214,7 @@ int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command,
/* Identifiers passed down: (BVCI, NSEI) */
/* Send BSSGP-DL-UNITDATA.req */
return gprs_bssgp_tx_dl_ud(msg);
}
@ -272,6 +274,7 @@ int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command)
/* Identifiers passed down: (BVCI, NSEI) */
/* Send BSSGP-DL-UNITDATA.req */
return gprs_bssgp_tx_dl_ud(msg);
}
@ -437,6 +440,7 @@ static int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
}
} else if ((ctrl[0] & 0xe0) == 0xc0) {
/* UI (Unconfirmed Inforamtion) format */
ghp->cmd = GPRS_LLC_UI;
ghp->data = ctrl + 2;
ghp->data_len = (llc_hdr + len - 3) - ghp->data;
@ -491,6 +495,12 @@ static int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
ghp->fcs_calc = gprs_llc_fcs(llc_hdr, crc_length);
/* FIXME: parse sack frame */
if (ghp->cmd == GPRS_LLC_SACK) {
DEBUGP(DGPRS, "Unsupported SACK frame\n");
return -EIO;
}
return 0;
}
/* receive an incoming LLC PDU (BSSGP-UL-UNITDATA-IND, 7.2.4.2) */
@ -505,37 +515,56 @@ int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
/* Identifiers from DOWN: NSEI, BVCI, TLLI */
rc = gprs_llc_hdr_parse(&llhp, lh, TLVP_LEN(tv, BSSGP_IE_LLC_PDU));
/* FIXME */
gprs_llc_hdr_dump(&llhp);
if (rc < 0) {
DEBUGP(DGPRS, "Error during LLC header parsing\n");
return rc;
}
if (llhp.fcs != llhp.fcs_calc) {
DEBUGP(DGPRS, "Dropping frame with invalid FCS\n");
return -EIO;
}
/* find the LLC Entity for this TLLI+SAPI tuple */
lle = lle_by_tlli_sapi(msgb_tlli(msg), llhp.sapi);
/* allocate a new LLE if needed */
if (!lle)
/* 7.2.1.1 LLC belonging to unassigned TLLI+SAPI shall be discarded,
* except UID and XID frames with SAPI=1 */
if (!lle && llhp.sapi == GPRS_SAPI_GMM &&
(llhp.cmd == GPRS_LLC_XID || llhp.cmd == GPRS_LLC_UI)) {
/* FIXME: don't use the TLLI but the 0xFFFF unassigned? */
lle = lle_alloc(msgb_tlli(msg), llhp.sapi);
} else {
DEBUGP(DGPRS, "unknown TLLI/SAPI: Silently dropping\n");
return 0;
}
/* Update LLE's (BVCI, NSEI) tuple */
lle->bvci = msgb_bvci(msg);
lle->nsei = msgb_nsei(msg);
/* Receive and Process the actual LLC frame */
rc = gprs_llc_hdr_rx(&llhp, lle);
/* FIXME */
if (rc < 0)
return rc;
/* llhp.data is only set when we need to send LL_[UNIT]DATA_IND up */
if (llhp.data) {
msgb_gmmh(msg) = llhp.data;
switch (llhp.sapi) {
case GPRS_SAPI_GMM:
/* send LL_UNITDATA_IND to GMM */
rc = gsm0408_gprs_rcvmsg(msg);
break;
case GPRS_SAPI_TOM2:
case GPRS_SAPI_TOM8:
/* FIXME */
/* FIXME: send LL_DATA_IND/LL_UNITDATA_IND to TOM */
case GPRS_SAPI_SNDCP3:
case GPRS_SAPI_SNDCP5:
case GPRS_SAPI_SNDCP9:
case GPRS_SAPI_SNDCP11:
/* FIXME */
/* FIXME: send LL_DATA_IND/LL_UNITDATA_IND to SNDCP */
case GPRS_SAPI_SMS:
/* FIXME */
default: