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[gprs] LLC: API to send XID responses to XID commands

This commit is contained in:
Harald Welte 2010-05-03 12:28:12 +02:00
parent 86fda90d03
commit 10997d0b9b
2 changed files with 67 additions and 14 deletions
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10
openbsc/include/openbsc/gprs_llc.h
View File

@ -15,6 +15,16 @@ enum gprs_llc_sapi {
GPRS_SAPI_SNDCP11 = 11,
};
/* Section 6.4 Commands and Responses */
enum gprs_llc_u_cmd {
GPRS_LLC_U_DM_RESP = 0x01,
GPRS_LLC_U_DISC_CMD = 0x04,
GPRS_LLC_U_UA_RESP = 0x06,
GPRS_LLC_U_SABM_CMD = 0x07,
GPRS_LLC_U_FRMR_RESP = 0x08,
GPRS_LLC_U_XID = 0x0b,
GPRS_LLC_U_NULL_CMD = 0x00,
};
int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv);
int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command);

71
openbsc/src/gprs_llc.c
View File

@ -142,19 +142,6 @@ static int gprs_llc_fcs(uint8_t *data, unsigned int len)
return fcs_calc;
}
/* transmit a simple U frame */
static int gprs_llc_tx_u()
{
struct msgb *msg = msgb_alloc(LLC_ALLOC_SIZE, "GPRS/LLC");
if (!msg)
return -ENOMEM;
/* transmit the frame via BSSGP->NS->... */
}
static void t200_expired(void *data)
{
struct gprs_llc_lle *lle = data;
@ -192,6 +179,53 @@ static void t201_expired(void *data)
}
}
int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command,
enum gprs_llc_u_cmd u_cmd, int pf_bit)
{
uint8_t *fcs, *llch;
uint8_t addr, ctrl;
uint32_t fcs_calc;
/* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */
/* Address Field */
addr = sapi & 0xf;
if (command)
addr |= 0x40;
/* 6.3 Figure 8 */
ctrl = 0xe0 | u_cmd;
if (pf_bit)
ctrl |= 0x10;
/* prepend LLC UI header */
llch = msgb_push(msg, 2);
llch[0] = addr;
llch[1] = ctrl;
/* append FCS to end of frame */
fcs = msgb_put(msg, 3);
fcs_calc = gprs_llc_fcs(llch, fcs - llch);
fcs[0] = fcs_calc & 0xff;
fcs[1] = (fcs_calc >> 8) & 0xff;
fcs[2] = (fcs_calc >> 16) & 0xff;
/* Identifiers passed down: (BVCI, NSEI) */
return gprs_bssgp_tx_dl_ud(msg);
}
/* Send XID response to LLE */
static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg)
{
/* copy identifiers from LLE to ensure lower layers can route */
msgb_tlli(msg) = lle->tlli;
msgb_bvci(msg) = lle->bvci;
msgb_nsei(msg) = lle->nsei;
return gprs_llc_tx_u(msg, lle->sapi, 0, GPRS_LLC_U_XID, 1);
}
/* Transmit a UI frame over the given SAPI */
int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command)
{
@ -257,6 +291,8 @@ static int gprs_llc_hdr_dump(struct gprs_llc_hdr_parsed *gph)
static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph,
struct gprs_llc_lle *lle)
{
struct msgb *resp;
switch (gph->cmd) {
case GPRS_LLC_SABM: /* Section 6.4.1.1 */
lle->v_sent = lle->v_ack = lle->v_recv = 0;
@ -284,6 +320,9 @@ static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph,
case GPRS_LLC_FRMR: /* Section 6.4.1.5 */
break;
case GPRS_LLC_XID: /* Section 6.4.1.6 */
/* FIXME: implement XID negotiation */
resp = msgb_alloc_headroom(4096, 1024, "LLC_XID");
gprs_llc_tx_xid(lle, resp);
break;
}
@ -449,7 +488,7 @@ int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
struct bssgp_ud_hdr *udh = (struct bssgp_ud_hdr *) msgb_bssgph(msg);
struct gprs_llc_hdr *lh = msgb_llch(msg);
struct gprs_llc_hdr_parsed llhp;
struct gprs_llc_entity *lle;
struct gprs_llc_lle *lle;
int rc = 0;
/* Identifiers from DOWN: NSEI, BVCI, TLLI */
@ -465,6 +504,10 @@ int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
if (!lle)
lle = lle_alloc(msgb_tlli(msg), llhp.sapi);
/* Update LLE's (BVCI, NSEI) tuple */
lle->bvci = msgb_bvci(msg);
lle->nsei = msgb_nsei(msg);
rc = gprs_llc_hdr_rx(&llhp, lle);
/* FIXME */