diff options
| author | Daniel Willmann <dwillmann@sysmocom.de> | 2021-02-12 01:57:52 +0100 |
|---|---|---|
| committer | daniel <dwillmann@sysmocom.de> | 2021-02-12 14:19:20 +0000 |
| commit | fa632b8e80edad72b4413aac6886030c806929b9 (patch) | |
| tree | 6a74d818aaf9354ba1a78229ea3c00029c59293b /src | |
| parent | 1ff86f7cec32d39b84effa896569f8fc7ca703d2 (diff) | |
bssgp2_enc_status: Truncate STATUS message to maximum PDU length
Related: OS#4889
Change-Id: Ic39d918c56399ceb0431299ce938e3bf276f678a
Diffstat (limited to 'src')
| -rw-r--r-- | src/gb/bssgp_bvc_fsm.c | 2 | ||||
| -rw-r--r-- | src/gb/gprs_bssgp2.c | 19 |
2 files changed, 16 insertions, 5 deletions
diff --git a/src/gb/bssgp_bvc_fsm.c b/src/gb/bssgp_bvc_fsm.c index d2ee1462..a0359386 100644 --- a/src/gb/bssgp_bvc_fsm.c +++ b/src/gb/bssgp_bvc_fsm.c @@ -238,7 +238,7 @@ static void _tx_status(struct osmo_fsm_inst *fi, enum gprs_bssgp_cause cause, co if (cause == BSSGP_CAUSE_UNKNOWN_BVCI || cause == BSSGP_CAUSE_BVCI_BLOCKED) bvci = &bfp->bvci; - tx = bssgp2_enc_status(cause, bvci, rx); + tx = bssgp2_enc_status(cause, bvci, rx, bfp->max_pdu_len); if (msgb_bvci(rx) == 0) fi_tx_sig(fi, tx); diff --git a/src/gb/gprs_bssgp2.c b/src/gb/gprs_bssgp2.c index 0f519adb..8e2ba66c 100644 --- a/src/gb/gprs_bssgp2.c +++ b/src/gb/gprs_bssgp2.c @@ -217,8 +217,9 @@ struct msgb *bssgp2_enc_bvc_reset_ack(uint16_t bvci, const struct gprs_ra_id *ra /*! Encode BSSGP STATUS PDU as per TS 48.018 Section 10.4.14. * \param[in] cause BSSGP Cause value * \param[in] bvci optional BVCI - only encoded if non-NULL - * \param[in] msg optional message buffer containing PDU in error - only encoded if non-NULL */ -struct msgb *bssgp2_enc_status(uint8_t cause, const uint16_t *bvci, const struct msgb *orig_msg) + * \param[in] msg optional message buffer containing PDU in error - only encoded if non-NULL + * \param[in] max_pdu_len Maximum BSSGP PDU size the NS layer accepts */ +struct msgb *bssgp2_enc_status(uint8_t cause, const uint16_t *bvci, const struct msgb *orig_msg, uint16_t max_pdu_len) { struct msgb *msg = bssgp_msgb_alloc(); struct bssgp_normal_hdr *bgph; @@ -229,12 +230,22 @@ struct msgb *bssgp2_enc_status(uint8_t cause, const uint16_t *bvci, const struct bgph = (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph)); bgph->pdu_type = BSSGP_PDUT_STATUS; msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, &cause); + /* FIXME: Require/encode BVCI only if cause is BVCI unknown/blocked + * See 3GPP TS 48.018 Ch. 10.4.14 */ if (bvci) { uint16_t _bvci = osmo_htons(*bvci); msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci); } - if (orig_msg) - msgb_tvlv_put(msg, BSSGP_IE_PDU_IN_ERROR, msgb_bssgp_len(orig_msg), msgb_bssgph(orig_msg)); + if (orig_msg) { + uint32_t orig_len, max_orig_len; + /* Calculate how big the reply would be: the BSSGP msg so far + size of the PDU IN ERROR including tvl */ + orig_len = msgb_bssgp_len(orig_msg); + max_orig_len = msgb_length(msg) + TVLV_GROSS_LEN(orig_len); + /* Truncate the difference between max_orig_len and mtu */ + if (max_orig_len > max_pdu_len) + orig_len -= max_orig_len - max_pdu_len; + msgb_tvlv_put(msg, BSSGP_IE_PDU_IN_ERROR, orig_len, msgb_bssgph(orig_msg)); + } return msg; } |