<p>Harald Welte <strong>merged</strong> this change.</p><p><a href="https://gerrit.osmocom.org/11163">View Change</a></p><div style="white-space:pre-wrap">Approvals:
Jenkins Builder: Verified
Harald Welte: Looks good to me, approved
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">Fix computing CCCH block number from frame number<br><br>The existing implementation used a simplistic macro, which was wrong<br>in many ways:<br><br>1) it returned a negative value for "fn % 51 < 5" conditions without<br> raising any error message or asserting<br>2) it returned a wrong block number for many different input frame<br> numbers, as it didn't account properly for the FCCH/SCH gaps between<br> the blocks<br><br>Let's replace the simplistic macro with a proper lookup table based on<br>TS 05.02, and let's OSMO_ASSERT() if this is ever called with non-CCCH<br>frame numbers.<br><br>Change-Id: I11fd6cc558bb61c40c2019e46f56c1fe78ef39f5<br>Closes: OS#3024<br>---<br>M include/osmo-bts/l1sap.h<br>M src/common/l1sap.c<br>M src/osmo-bts-litecell15/l1_if.c<br>M src/osmo-bts-sysmo/l1_if.c<br>M src/osmo-bts-virtual/scheduler_virtbts.c<br>5 files changed, 41 insertions(+), 6 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/include/osmo-bts/l1sap.h b/include/osmo-bts/l1sap.h</span><br><span>index 3225a60..e2c92fa 100644</span><br><span>--- a/include/osmo-bts/l1sap.h</span><br><span>+++ b/include/osmo-bts/l1sap.h</span><br><span>@@ -29,7 +29,7 @@</span><br><span> #define L1SAP_IS_PACKET_RACH(ra) ((ra & 0xf0) == 0x70 && (ra & 0x0f) != 0x0f)</span><br><span> </span><br><span> /* CCCH block from frame number */</span><br><span style="color: hsl(0, 100%, 40%);">-#define L1SAP_FN2CCCHBLOCK(fn) ((fn % 51) / 5 - 1)</span><br><span style="color: hsl(120, 100%, 40%);">+unsigned int l1sap_fn2ccch_block(uint32_t fn);</span><br><span> </span><br><span> /* PTCH layout from frame number */</span><br><span> #define L1SAP_FN2MACBLOCK(fn) ((fn % 52) / 4)</span><br><span>diff --git a/src/common/l1sap.c b/src/common/l1sap.c</span><br><span>index ac4f0be..0f3cd3a 100644</span><br><span>--- a/src/common/l1sap.c</span><br><span>+++ b/src/common/l1sap.c</span><br><span>@@ -55,6 +55,41 @@</span><br><span> #include <osmo-bts/pcuif_proto.h></span><br><span> #include <osmo-bts/cbch.h></span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+#define CB_FCCH -1</span><br><span style="color: hsl(120, 100%, 40%);">+#define CB_SCH -2</span><br><span style="color: hsl(120, 100%, 40%);">+#define CB_BCCH -3</span><br><span style="color: hsl(120, 100%, 40%);">+#define CB_IDLE -4</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+/* according to TS 05.02 Clause 7 Table 3 of 9 an Figure 8a */</span><br><span style="color: hsl(120, 100%, 40%);">+static const int ccch_block_table[51] = {</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_FCCH, CB_SCH,/* 0..1 */</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_BCCH, CB_BCCH, CB_BCCH, CB_BCCH, /* 2..5: BCCH */</span><br><span style="color: hsl(120, 100%, 40%);">+ 0, 0, 0, 0, /* 6..9: B0 */</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_FCCH, CB_SCH,/* 10..11 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 1, 1, 1, 1, /* 12..15: B1 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 2, 2, 2, 2, /* 16..19: B2 */</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_FCCH, CB_SCH,/* 20..21 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 3, 3, 3, 3, /* 22..25: B3 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 4, 4, 4, 4, /* 26..29: B4 */</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_FCCH, CB_SCH,/* 30..31 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 5, 5, 5, 5, /* 32..35: B5 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 6, 6, 6, 6, /* 36..39: B6 */</span><br><span style="color: hsl(120, 100%, 40%);">+ CB_FCCH, CB_SCH,/* 40..41 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 7, 7, 7, 7, /* 42..45: B7 */</span><br><span style="color: hsl(120, 100%, 40%);">+ 8, 8, 8, 8, /* 46..49: B8 */</span><br><span style="color: hsl(120, 100%, 40%);">+ -4 /* 50: Idle */</span><br><span style="color: hsl(120, 100%, 40%);">+};</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+/* determine the CCCH block number based on the frame number */</span><br><span style="color: hsl(120, 100%, 40%);">+unsigned int l1sap_fn2ccch_block(uint32_t fn)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ int rc = ccch_block_table[fn%51];</span><br><span style="color: hsl(120, 100%, 40%);">+ /* if FN is negative, we were called for something that's not CCCH! */</span><br><span style="color: hsl(120, 100%, 40%);">+ OSMO_ASSERT(rc >= 0);</span><br><span style="color: hsl(120, 100%, 40%);">+ return rc;</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> struct gsm_lchan *get_lchan_by_chan_nr(struct gsm_bts_trx *trx,</span><br><span> unsigned int chan_nr)</span><br><span> {</span><br><span>@@ -273,7 +308,7 @@</span><br><span> } else if (L1SAP_IS_CHAN_AGCH_PCH(chan_nr)) {</span><br><span> /* The sapi depends on DSP configuration, not</span><br><span> * on the actual SYSTEM INFORMATION 3. */</span><br><span style="color: hsl(0, 100%, 40%);">- if (L1SAP_FN2CCCHBLOCK(fn) >= num_agch)</span><br><span style="color: hsl(120, 100%, 40%);">+ if (l1sap_fn2ccch_block(fn) >= num_agch)</span><br><span> *chan_type = GSMTAP_CHANNEL_PCH;</span><br><span> else</span><br><span> *chan_type = GSMTAP_CHANNEL_AGCH;</span><br><span>@@ -686,7 +721,7 @@</span><br><span> /* Note: The number of available access grant channels is set by the</span><br><span> * parameter BS_AG_BLKS_RES via system information type 3. This SI is</span><br><span> * transfered to osmo-bts via RSL */</span><br><span style="color: hsl(0, 100%, 40%);">- return L1SAP_FN2CCCHBLOCK(fn) < num_agch(trx, "PH-RTS-IND");</span><br><span style="color: hsl(120, 100%, 40%);">+ return l1sap_fn2ccch_block(fn) < num_agch(trx, "PH-RTS-IND");</span><br><span> }</span><br><span> </span><br><span> /* PH-RTS-IND prim received from bts model */</span><br><span>diff --git a/src/osmo-bts-litecell15/l1_if.c b/src/osmo-bts-litecell15/l1_if.c</span><br><span>index 4093225..99852e3 100644</span><br><span>--- a/src/osmo-bts-litecell15/l1_if.c</span><br><span>+++ b/src/osmo-bts-litecell15/l1_if.c</span><br><span>@@ -388,7 +388,7 @@</span><br><span> } else if (L1SAP_IS_CHAN_AGCH_PCH(chan_nr)) {</span><br><span> /* The sapi depends on DSP configuration, not</span><br><span> * on the actual SYSTEM INFORMATION 3. */</span><br><span style="color: hsl(0, 100%, 40%);">- u8BlockNbr = L1SAP_FN2CCCHBLOCK(u32Fn);</span><br><span style="color: hsl(120, 100%, 40%);">+ u8BlockNbr = l1sap_fn2ccch_block(u32Fn);</span><br><span> if (u8BlockNbr >= num_agch(trx, "PH-DATA-REQ"))</span><br><span> sapi = GsmL1_Sapi_Pch;</span><br><span> else</span><br><span>diff --git a/src/osmo-bts-sysmo/l1_if.c b/src/osmo-bts-sysmo/l1_if.c</span><br><span>index 372e332..247c371 100644</span><br><span>--- a/src/osmo-bts-sysmo/l1_if.c</span><br><span>+++ b/src/osmo-bts-sysmo/l1_if.c</span><br><span>@@ -385,7 +385,7 @@</span><br><span> } else if (L1SAP_IS_CHAN_AGCH_PCH(chan_nr)) {</span><br><span> /* The sapi depends on DSP configuration, not</span><br><span> * on the actual SYSTEM INFORMATION 3. */</span><br><span style="color: hsl(0, 100%, 40%);">- u8BlockNbr = L1SAP_FN2CCCHBLOCK(u32Fn);</span><br><span style="color: hsl(120, 100%, 40%);">+ u8BlockNbr = l1sap_fn2ccch_block(u32Fn);</span><br><span> if (u8BlockNbr >= 1)</span><br><span> sapi = GsmL1_Sapi_Pch;</span><br><span> else</span><br><span>diff --git a/src/osmo-bts-virtual/scheduler_virtbts.c b/src/osmo-bts-virtual/scheduler_virtbts.c</span><br><span>index cdbb9c1..997ccbc 100644</span><br><span>--- a/src/osmo-bts-virtual/scheduler_virtbts.c</span><br><span>+++ b/src/osmo-bts-virtual/scheduler_virtbts.c</span><br><span>@@ -79,7 +79,7 @@</span><br><span> timeslot = tn;</span><br><span> /* in Osmocom, AGCH is only sent on ccch block 0. no idea why. this seems to cause false GSMTAP channel</span><br><span> * types for agch and pch. */</span><br><span style="color: hsl(0, 100%, 40%);">- if (rsl_chantype == RSL_CHAN_PCH_AGCH && L1SAP_FN2CCCHBLOCK(fn) == 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ if (rsl_chantype == RSL_CHAN_PCH_AGCH && l1sap_fn2ccch_block(fn) == 0)</span><br><span> gsmtap_chantype = GSMTAP_CHANNEL_PCH;</span><br><span> else</span><br><span> gsmtap_chantype = chantype_rsl2gsmtap(rsl_chantype, chdesc->link_id); /* the logical channel type */</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/11163">change 11163</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/11163"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: osmo-bts </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: merged </div>
<div style="display:none"> Gerrit-Change-Id: I11fd6cc558bb61c40c2019e46f56c1fe78ef39f5 </div>
<div style="display:none"> Gerrit-Change-Number: 11163 </div>
<div style="display:none"> Gerrit-PatchSet: 2 </div>
<div style="display:none"> Gerrit-Owner: Harald Welte <laforge@gnumonks.org> </div>
<div style="display:none"> Gerrit-Reviewer: Harald Welte <laforge@gnumonks.org> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder (1000002) </div>