From 8dac4159adb7377f016317808e3a6b0c79df7fa1 Mon Sep 17 00:00:00 2001 From: Jacob Erlbeck Date: Tue, 28 Jan 2014 11:03:11 +0100 Subject: ladpm: Fix msgb handling and SAPI=3 establishment delay Currently it takes 3s to establish a SAPI 3 SACCH connection with osmo-bts. This is due to the fact, that a broken SABME request is sent first and and is ignored by the MS. Then, after a T200 timeout (2s) the SABME command is sent again (this time correctly) and answered by the MS. The first SABME message is broken (it has a length field of 3 and ends with 3 bytes from the tail of the original RSL message), because of it is expected throughout lapdm.c that msg buffers containing RSL have msg->l2h == msg->data. Some abis input drivers fulfill this but IPA doesn't, thus the 3 bytes of the IPA header are still part of the msg and confuse length computation. Since internal fields of the msg are modified directly, this is difficult to see. This patch adds a new function msgb_pull_to_l3() that explicitely skips over all headers prepending L3 and therefore resets l1h and l2h. This function is then used instead of msgb_pull_l2h() which only worked correctly when msg->l2h == msg->data. In addition, code manipulating msg->tail and msg->len directly has been replaced by calls to msgb_trim(). Note that this patch does not fix all issues of this case in the LADP related code. Ticket: SYS#192 Sponsored-by: On-Waves ehf --- tests/lapd/lapd_test.ok | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'tests') diff --git a/tests/lapd/lapd_test.ok b/tests/lapd/lapd_test.ok index 7d266bdd..9fb58e0c 100644 --- a/tests/lapd/lapd_test.ok +++ b/tests/lapd/lapd_test.ok @@ -33,9 +33,9 @@ Took message from DCCH queue: L2 header size 3, L3 size 20, SAP 0x1000000, 0/0, Message: [L2]> 01 73 41 [L3]> 05 24 31 03 50 18 93 08 29 47 80 00 00 00 00 80 2b 2b 2b 2b I test RF channel establishment. Testing SAPI3/SDCCH -Took message from DCCH queue: L2 header size 6, L3 size 17, SAP 0x1000000, 0/0, Link 0x03 -Message: [L2]> 0f 3f 0d 20 02 03 [L3]> 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b +Took message from DCCH queue: L2 header size 3, L3 size 20, SAP 0x1000000, 0/0, Link 0x03 +Message: [L2]> 0f 3f 01 [L3]> 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b Testing SAPI3/SACCH -Took message from ACCH queue: L2 header size 8, L3 size 15, SAP 0x1000000, 0/0, Link 0x43 -Message: [L2]> 00 00 0f 3f 0d 0b 02 43 [L3]> 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b +Took message from ACCH queue: L2 header size 5, L3 size 18, SAP 0x1000000, 0/0, Link 0x43 +Message: [L2]> 00 00 0f 3f 01 [L3]> 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b Success. -- cgit v1.2.3