<p>laforge <strong>submitted</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/osmo-trx/+/18006">View Change</a></p><div style="white-space:pre-wrap">Approvals:
pespin: Looks good to me, but someone else must approve
laforge: Looks good to me, approved
Jenkins Builder: Verified
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">prbs-tool: Add error simulation capabilities<br><br>The tool can now simulate:<br>* lost bursts on the TRX->BTS interface<br>* zeroed/overwritten bursts on the TRX->BTS interface<br>* errors in the TCH codec frames before passing them to the encoder<br><br>Change-Id: I0b52c2af6d973669ac233bf9868400e497496460<br>TODO: Ability to introduce errors in certain classes of the bits only.<br>---<br>M utils/prbs-tool.c<br>1 file changed, 79 insertions(+), 12 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/utils/prbs-tool.c b/utils/prbs-tool.c</span><br><span>index de68f0b..0211453 100644</span><br><span>--- a/utils/prbs-tool.c</span><br><span>+++ b/utils/prbs-tool.c</span><br><span>@@ -55,7 +55,7 @@</span><br><span> uint32_t fn;</span><br><span> uint8_t rssi;</span><br><span> uint16_t t_offs;</span><br><span style="color: hsl(0, 100%, 40%);">- sbit_t bits[148];</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t bits[148]; /* 0..255, *NOT* sbit_t */</span><br><span> } __attribute__((packed));</span><br><span> </span><br><span> struct trx_dl_msg {</span><br><span>@@ -134,6 +134,26 @@</span><br><span> unsigned int burst_nr;</span><br><span> /* training sequence code */</span><br><span> unsigned int tsc;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* loose 'count' bursts every 'nth_mframe' on TRX-BTS interface */</span><br><span style="color: hsl(120, 100%, 40%);">+ struct {</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int count;</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int nth_mframe;</span><br><span style="color: hsl(120, 100%, 40%);">+ } sim_lost_bursts;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* zero 'count' bursts every 'nth_mframe' on TRX-BTS interface */</span><br><span style="color: hsl(120, 100%, 40%);">+ struct {</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int count;</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int nth_mframe;</span><br><span style="color: hsl(120, 100%, 40%);">+ } sim_zero_bursts;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* flip every 'nth_bit' of the PRNG oudput before encoding */</span><br><span style="color: hsl(120, 100%, 40%);">+ struct {</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int nth_bit;</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int i;</span><br><span style="color: hsl(120, 100%, 40%);">+ } sim_flip_codec_bits;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int i;</span><br><span> };</span><br><span> </span><br><span> struct ts_data {</span><br><span>@@ -164,6 +184,18 @@</span><br><span> }</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/* apply any intentional errors to the output of the PRBS sequence */</span><br><span style="color: hsl(120, 100%, 40%);">+static void apply_errors_prbs(struct pchan_data *pchan)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ for (int i = 0; i < sizeof(pchan->prbs_u)-4; i++) {</span><br><span style="color: hsl(120, 100%, 40%);">+ pchan->sim_flip_codec_bits.i++;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pchan->sim_flip_codec_bits.i == pchan->sim_flip_codec_bits.nth_bit) {</span><br><span style="color: hsl(120, 100%, 40%);">+ pchan->sim_flip_codec_bits.i = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ pchan->prbs_u[4+i] ^= 0x01;</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%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /*! obtain the next to-be-transmitted burst for the given pchan</span><br><span> * \param pchan physical channel on which we operate</span><br><span> * \param[in] fn frame number</span><br><span>@@ -188,6 +220,9 @@</span><br><span> osmo_pbit2ubit(pchan->prbs_u, prefix, 4);</span><br><span> rc = osmo_prbs_get_ubits(pchan->prbs_u+4, sizeof(pchan->prbs_u)-4, &pchan->st);</span><br><span> OSMO_ASSERT(rc == sizeof(pchan->prbs_u)-4);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_errors_prbs(pchan);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* pack to PBIT format */</span><br><span> rc = osmo_ubit2pbit(pchan->tch_data, pchan->prbs_u, sizeof(pchan->prbs_u));</span><br><span> //memset(pchan->tch_data, 0xff, sizeof(pchan->tch_data));</span><br><span>@@ -201,16 +236,17 @@</span><br><span> /* encode block (codec frame) into four bursts */</span><br><span> rc = gsm0503_tch_fr_encode(pchan->bursts, pchan->tch_data, GSM_FR_BYTES, 1);</span><br><span> OSMO_ASSERT(rc == 0);</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(120, 100%, 40%);">+#if 0</span><br><span> for (int i = 0; i < sizeof(pchan->bursts); i += GSM_BURST_BITS)</span><br><span> printf("\t%s\n", osmo_ubit_dump(pchan->bursts + i, GSM_BURST_BITS));</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-// dec(pchan->bursts);</span><br><span style="color: hsl(120, 100%, 40%);">+ dec(pchan->bursts);</span><br><span style="color: hsl(120, 100%, 40%);">+#endif</span><br><span> }</span><br><span> </span><br><span> /* for all bursts: format 148 symbols from 116 input bits */</span><br><span> ubit_t *burst = pchan->bursts + pchan->burst_nr * GSM_BURST_BITS;</span><br><span style="color: hsl(0, 100%, 40%);">- printf("TX(%u): %s\n", pchan->burst_nr, osmo_ubit_dump(burst, GSM_BURST_BITS));</span><br><span style="color: hsl(120, 100%, 40%);">+// printf("TX(%u): %s\n", pchan->burst_nr, osmo_ubit_dump(burst, GSM_BURST_BITS));</span><br><span> memset(burst_out, 0, 3); /* guard bits */</span><br><span> memcpy(burst_out+3, burst, 58); /* firrst half */</span><br><span> memcpy(burst_out+61, _sched_tsc[pchan->tsc], 26); /* midamble */</span><br><span>@@ -219,10 +255,6 @@</span><br><span> </span><br><span> /* increment burst number for next call */</span><br><span> pchan->burst_nr += 1;</span><br><span style="color: hsl(0, 100%, 40%);">-#if 0</span><br><span style="color: hsl(0, 100%, 40%);">- if (pchan->burst_nr == 4)</span><br><span style="color: hsl(0, 100%, 40%);">- pchan->burst_nr = 0;</span><br><span style="color: hsl(0, 100%, 40%);">-#endif</span><br><span> </span><br><span> return GSM_BURST_LEN;</span><br><span> }</span><br><span>@@ -252,6 +284,7 @@</span><br><span> struct trx_ul_msg *ul_msg = (struct trx_ul_msg *) tx_ul_buf;</span><br><span> /* other variables */</span><br><span> struct pchan_data *pchan;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint32_t fn;</span><br><span> uint8_t rc;</span><br><span> </span><br><span> /* do a blocking read on the socket and receive DL from BTS */</span><br><span>@@ -259,7 +292,7 @@</span><br><span> if (rc < sizeof(*dl_msg))</span><br><span> return rc;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- dl_msg->fn = ntohl(dl_msg->fn);</span><br><span style="color: hsl(120, 100%, 40%);">+ fn = ntohl(dl_msg->fn);</span><br><span> </span><br><span> if (dl_msg->ts >= ARRAY_SIZE(g_trx_data.ts))</span><br><span> return -ENODEV;</span><br><span>@@ -267,18 +300,48 @@</span><br><span> if (dl_msg->ts != 2)</span><br><span> return 0;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- printf("FN=%s TS=%u\n", gsm_fn_as_gsmtime_str(dl_msg->fn), dl_msg->ts);</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("FN=%s TS=%u\n", gsm_fn_as_gsmtime_str(fn), dl_msg->ts);</span><br><span> </span><br><span> /* FIXME: second pchan for TCH/H */</span><br><span> pchan = &g_trx_data.ts[dl_msg->ts].pchan[0];</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- rc = pchan_process_ts_fn(pchan, dl_msg->fn, (uint8_t *) ul_msg->bits);</span><br><span style="color: hsl(120, 100%, 40%);">+ rc = pchan_process_ts_fn(pchan, fn, (uint8_t *) ul_msg->bits);</span><br><span> OSMO_ASSERT(rc == sizeof(ul_msg->bits));</span><br><span> </span><br><span> /* copy over timeslot and frame number */</span><br><span style="color: hsl(0, 100%, 40%);">- ul_msg->fn = htonl(dl_msg->fn);</span><br><span style="color: hsl(120, 100%, 40%);">+ ul_msg->fn = htonl(fn);</span><br><span> ul_msg->ts = dl_msg->ts;</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* simulate lost frames on TRX <-> BTS interface */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pchan->sim_lost_bursts.count) {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* count number of 26-multiframes */</span><br><span style="color: hsl(120, 100%, 40%);">+ static int count = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (fn % 26 == 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ count++;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* every 10th multiframe, drop two entire block of 8 bursts */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (count % pchan->sim_lost_bursts.nth_mframe == 0 &&</span><br><span style="color: hsl(120, 100%, 40%);">+ (fn % 26) <= pchan->sim_lost_bursts.count) {</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("===> SKIPPING BURST\n");</span><br><span style="color: hsl(120, 100%, 40%);">+ return 0;</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%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* simulate zero-ed frames on TRX <-> BTS interface */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pchan->sim_zero_bursts.count) {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* count number of 26-multiframes */</span><br><span style="color: hsl(120, 100%, 40%);">+ static int count = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (fn % 26 == 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ count++;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* every 10th multiframe, drop two entire block of 8 bursts */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (count % pchan->sim_zero_bursts.nth_mframe == 0 &&</span><br><span style="color: hsl(120, 100%, 40%);">+ (fn % 26) <= pchan->sim_zero_bursts.count) {</span><br><span style="color: hsl(120, 100%, 40%);">+ memset(ul_msg->bits, 0, sizeof(ul_msg->bits));</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("===> ZEROING BURST\n");</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%);">+</span><br><span> /* write uplink message towards BTS */</span><br><span> rc = write(fd, tx_ul_buf, sizeof(*ul_msg));</span><br><span> if (rc < sizeof(*ul_msg))</span><br><span>@@ -304,6 +367,10 @@</span><br><span> </span><br><span> trx_data_init(&g_trx_data);</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ //g_trx_data.ts[2].pchan[0].sim_zero_bursts.count = 8;</span><br><span style="color: hsl(120, 100%, 40%);">+ //g_trx_data.ts[2].pchan[0].sim_zero_bursts.nth_mframe = 10;</span><br><span style="color: hsl(120, 100%, 40%);">+ g_trx_data.ts[2].pchan[0].sim_flip_codec_bits.nth_bit = 260*4;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> fd = open_trx_data_sock(0, "127.0.0.1");</span><br><span> if (fd < 0)</span><br><span> exit(1);</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-trx/+/18006">change 18006</a>. 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<div style="display:none"> Gerrit-Project: osmo-trx </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I0b52c2af6d973669ac233bf9868400e497496460 </div>
<div style="display:none"> Gerrit-Change-Number: 18006 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>