Change in libosmocore[master]: CBSP: fix encoding/decoding of keep-alive repetition period

[laforge]

laforge has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/23017 )

Change subject: CBSP: fix encoding/decoding of keep-alive repetition period
......................................................................

CBSP: fix encoding/decoding of keep-alive repetition period

Even though the value is only between 0..120s, they didn't encode
it 1:1 in the uint8_t, but 3GPP chose to use the same encoding
as for the warning period (which has a much larger range).

Let's fix this in our implementation.

Before this patch, osmo-cbc wanted to send 30s keep-alive repetition
period, but a spec-compliant receiver actually decoded this as 80s.

Change-Id: I04baa6b6b99b092fa0512b3b6138a363c7f3a13d
---
M src/gsm/cbsp.c
1 file changed, 9 insertions(+), 2 deletions(-)

Approvals:
  Jenkins Builder: Verified
  pespin: Looks good to me, but someone else must approve
  laforge: Looks good to me, approved



diff --git a/src/gsm/cbsp.c b/src/gsm/cbsp.c
index 2c7a7b7..fa599c5 100644
--- a/src/gsm/cbsp.c
+++ b/src/gsm/cbsp.c
@@ -352,7 +352,12 @@
 /* 8.1.3.18a KEEP ALIVE */
 static int cbsp_enc_keep_alive(struct msgb *msg, const struct osmo_cbsp_keep_alive *in)
 {
-	msgb_tv_put(msg, CBSP_IEI_KEEP_ALIVE_REP_PERIOD, in->repetition_period);
+	int rperiod = encode_wperiod(in->repetition_period);
+	if (in->repetition_period > 120)
+		return -EINVAL;
+	if (rperiod < 0)
+		return -EINVAL;
+	msgb_tv_put(msg, CBSP_IEI_KEEP_ALIVE_REP_PERIOD, rperiod);
 	return 0;
 }
 
@@ -1083,12 +1088,14 @@
 static int cbsp_dec_keep_alive(struct osmo_cbsp_keep_alive *out, const struct tlv_parsed *tp,
 				struct msgb *in, void *ctx)
 {
+	uint8_t rperiod;
 	if (!TLVP_PRES_LEN(tp, CBSP_IEI_KEEP_ALIVE_REP_PERIOD, 1)) {
 		osmo_cbsp_errstr = "missing/short mandatory IE";
 		return -EINVAL;
 	}
 
-	out->repetition_period = *TLVP_VAL(tp, CBSP_IEI_KEEP_ALIVE_REP_PERIOD);
+	rperiod = *TLVP_VAL(tp, CBSP_IEI_KEEP_ALIVE_REP_PERIOD);
+	out->repetition_period = decode_wperiod(rperiod);
 	return 0;
 }
 

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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I04baa6b6b99b092fa0512b3b6138a363c7f3a13d
Gerrit-Change-Number: 23017
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <laforge at osmocom.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-Reviewer: pespin <pespin at sysmocom.de>
Gerrit-MessageType: merged
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