LAPDm: When Rx DATA from L1, L1 does not know the SAPI
We have to determine the SAPI ourselves inside the LAPDm header.
diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c
index b804a92..242544d 100644
--- a/src/gsm/lapdm.c
+++ b/src/gsm/lapdm.c
@@ -1573,34 +1573,23 @@
static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t chan_nr, uint8_t link_id)
{
uint8_t cbits = chan_nr >> 3;
- uint8_t sapi = link_id & 7;
+ uint8_t sapi; /* we cannot take SAPI from link_id, as L1 has no clue */
struct lapdm_msg_ctx mctx;
int rc = 0;
/* when we reach here, we have a msgb with l2h pointing to the raw
* 23byte mac block. The l1h has already been purged. */
- mctx.dl = datalink_for_sapi(le, sapi);
mctx.chan_nr = chan_nr;
mctx.link_id = link_id;
mctx.addr = mctx.ctrl = 0;
- /* G.2.1 No action schall be taken on frames containing an unallocated
- * SAPI.
- */
- if (!mctx.dl) {
- LOGP(DLLAPDM, LOGL_NOTICE, "Received frame for unsupported "
- "SAPI %d!\n", sapi);
- return -EINVAL;
- msgb_free(msg);
- return -EIO;
- }
-
/* check for L1 chan_nr/link_id and determine LAPDm hdr format */
if (cbits == 0x10 || cbits == 0x12) {
/* Format Bbis is used on BCCH and CCCH(PCH, NCH and AGCH) */
mctx.lapdm_fmt = LAPDm_FMT_Bbis;
mctx.n201 = N201_Bbis;
+ sapi = 0;
} else {
if (mctx.link_id & 0x40) {
/* It was received from network on SACCH, thus
@@ -1614,13 +1603,25 @@
mctx.ta_ind = msg->l2h[1];
msgb_pull(msg, 2);
msg->l2h += 2;
+ sapi = (msg->l2h[0] >> 2) & 7;
} else {
mctx.lapdm_fmt = LAPDm_FMT_B;
LOGP(DLLAPDM, LOGL_INFO, "fmt=B\n");
mctx.n201 = 23; // FIXME: select correct size by chan.
+ sapi = (msg->l2h[0] >> 2) & 7;
}
}
+ mctx.dl = datalink_for_sapi(le, sapi);
+ /* G.2.1 No action on frames containing an unallocated SAPI. */
+ if (!mctx.dl) {
+ LOGP(DLLAPDM, LOGL_NOTICE, "Received frame for unsupported "
+ "SAPI %d!\n", sapi);
+ return -EINVAL;
+ msgb_free(msg);
+ return -EIO;
+ }
+
switch (mctx.lapdm_fmt) {
case LAPDm_FMT_A:
case LAPDm_FMT_B: