[S] Change in osmo-e1d[master]: usb: Deal with truncated ISO IN transfers

laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-e1d/+/27579?usp=email ) Change subject: usb: Deal with truncated ISO IN transfers ...................................................................... usb: Deal with truncated ISO IN transfers It seems that in some circumstances, an ISO IN transfer can be truncated by the bus / host. In such situation we'd currently pass a non-modulo-32 length to the mux_demux (deframer) code, and it ASSERTs on that. Let's try to handle this more gracefully by substituting random garbage and letting higher layers deal with massive bit errors. Related: OS#5490 Change-Id: Ic453325b93b0e12727625a1495a948d96df4b542 --- M src/e1d.h M src/intf_line.c M src/usb.c 3 files changed, 45 insertions(+), 0 deletions(-) Approvals: manawyrm: Looks good to me, approved Jenkins Builder: Verified diff --git a/src/e1d.h b/src/e1d.h index 1c7c4c4..45ecb82 100644 --- a/src/e1d.h +++ b/src/e1d.h @@ -59,6 +59,7 @@ LINE_CTR_RX_REMOTE_A, LINE_CTR_FRAMES_MUXED_E1T, LINE_CTR_FRAMES_DEMUXED_E1O, + LINE_CTR_USB_ISO_TRUNC, }; enum e1d_line_stat_item { diff --git a/src/intf_line.c b/src/intf_line.c index 3895653..f41214e 100644 --- a/src/intf_line.c +++ b/src/intf_line.c @@ -60,6 +60,7 @@ [LINE_CTR_RX_REMOTE_A] ={ "rx:remote_alarm", "Rx Frames Reporting Remote Alarm"}, [LINE_CTR_FRAMES_MUXED_E1T] = { "tx:frames_muxed", "E1 Tx Frames multiplexed" }, [LINE_CTR_FRAMES_DEMUXED_E1O] = { "rx:frames_demuxed", "E1 Rx Frames demultiplexed" }, + [LINE_CTR_USB_ISO_TRUNC] = { "rx:usb_iso_trunc", "USB ISO packets truncated" }, }; static const struct rate_ctr_group_desc line_ctrg_desc = { diff --git a/src/usb.c b/src/usb.c index 1ff9b43..fcffc12 100644 --- a/src/usb.c +++ b/src/usb.c @@ -131,6 +131,33 @@ { if (len == 0) return 0; + + if (len < 4) { + LOGPLI(flow->line, DE1D, LOGL_ERROR, "IN EP %02x ISO packet truncated: len = %u\n", + flow->ep, len); + line_ctr_add(flow->line, LINE_CTR_USB_ISO_TRUNC, 1); + return 0; + } + + if (len > 4 && (len - 4) % 32) { + /* some ISO IN packet was truncated. Apparently this + * does happen, see https://osmocom.org/issues/5490 - + * there is little we can do here, but instead of the + * earlier ASSERT, we just feed some garbage for the + * last few timeslots, resulting in bit errors etc. */ + LOGPLI(flow->line, DE1D, LOGL_ERROR, "IN EP %02x ISO packet truncated: len-4 = %u\n", + flow->ep, len - 4); + line_ctr_add(flow->line, LINE_CTR_USB_ISO_TRUNC, 1); + + /* The assumption here is that only the last E1 frame is + * truncated, as we have no idea how many E1 frames the + * USB device firmware wanted to send us. */ + len += 32 - (len % 32); + /* don't overflow the underlying buffer */ + if (len > (int) size) + len = size; + } + return e1_line_demux_in(flow->line, buf + 4, len - 4, buf[3] & 0xf); } -- To view, visit https://gerrit.osmocom.org/c/osmo-e1d/+/27579?usp=email To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-e1d Gerrit-Branch: master Gerrit-Change-Id: Ic453325b93b0e12727625a1495a948d96df4b542 Gerrit-Change-Number: 27579 Gerrit-PatchSet: 6 Gerrit-Owner: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: manawyrm &lt;osmocom.account(a)tbspace.de&gt; Gerrit-Reviewer: tnt &lt;tnt(a)246tNt.com&gt; Gerrit-MessageType: merged