lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 5 Aug 2020 15:59:46 +0300 From: Grygorii Strashko <grygorii.strashko@...com> To: Kurt Kanzenbach <kurt@...utronix.de>, Russell King - ARM Linux admin <linux@...linux.org.uk> CC: Petr Machata <petrm@...lanox.com>, Richard Cochran <richardcochran@...il.com>, Andrew Lunn <andrew@...n.ch>, Vivien Didelot <vivien.didelot@...il.com>, Florian Fainelli <f.fainelli@...il.com>, "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, Jiri Pirko <jiri@...lanox.com>, Ido Schimmel <idosch@...lanox.com>, Heiner Kallweit <hkallweit1@...il.com>, Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>, Samuel Zou <zou_wei@...wei.com>, <netdev@...r.kernel.org> Subject: Re: [PATCH v3 1/9] ptp: Add generic ptp v2 header parsing function On 05/08/2020 12:29, Kurt Kanzenbach wrote: > On Wed Aug 05 2020, Russell King - ARM Linux admin wrote: >> On Wed, Aug 05, 2020 at 01:04:31AM +0300, Grygorii Strashko wrote: >>> On 05/08/2020 00:44, Russell King - ARM Linux admin wrote: >>>> On Wed, Aug 05, 2020 at 12:34:47AM +0300, Grygorii Strashko wrote: >>>>> On 05/08/2020 00:07, Russell King - ARM Linux admin wrote: >>>>>> On Tue, Aug 04, 2020 at 11:56:12PM +0300, Grygorii Strashko wrote: >>>>>>> >>>>>>> >>>>>>> On 31/07/2020 13:06, Kurt Kanzenbach wrote: >>>>>>>> On Thu Jul 30 2020, Petr Machata wrote: >>>>>>>>> Kurt Kanzenbach <kurt@...utronix.de> writes: >>>>>>>>> >>>>>>>>>> @@ -107,6 +107,37 @@ unsigned int ptp_classify_raw(const struct sk_buff *skb) >>>>>>>>>> } >>>>>>>>>> EXPORT_SYMBOL_GPL(ptp_classify_raw); >>>>>>>>>> +struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type) >>>>>>>>>> +{ >>>>>>>>>> + u8 *data = skb_mac_header(skb); >>>>>>>>>> + u8 *ptr = data; >>>>>>>>> >>>>>>>>> One of the "data" and "ptr" variables is superfluous. >>>>>>>> >>>>>>>> Yeah. Can be shortened to u8 *ptr = skb_mac_header(skb); >>>>>>> >>>>>>> Actually usage of skb_mac_header(skb) breaks CPTS RX time-stamping on >>>>>>> am571x platform PATCH 6. >>>>>>> >>>>>>> The CPSW RX timestamp requested after full packet put in SKB, but >>>>>>> before calling eth_type_trans(). >>>>>>> >>>>>>> So, skb->data pints on Eth header, but skb_mac_header() return garbage. >>>>>>> >>>>>>> Below diff fixes it for me. >>>>>> >>>>>> However, that's likely to break everyone else. >>>>>> >>>>>> For example, anyone calling this from the mii_timestamper rxtstamp() >>>>>> method, the skb will have been classified with the MAC header pushed >>>>>> and restored, so skb->data points at the network header. >>>>>> >>>>>> Your change means that ptp_parse_header() expects the MAC header to >>>>>> also be pushed. >>>>>> >>>>>> Is it possible to adjust CPTS? >>>>>> >>>>>> Looking at: >>>>>> drivers/net/ethernet/ti/cpsw.c... yes. >>>>>> drivers/net/ethernet/ti/cpsw_new.c... yes. >>>>>> drivers/net/ethernet/ti/netcp_core.c... unclear. >>>>>> >>>>>> If not, maybe cpts should remain unconverted - I don't see any reason >>>>>> to provide a generic function for one user. >>>>>> >>>>> >>>>> Could it be an option to pass "u8 *ptr" instead of "const struct sk_buff *skb" as >>>>> input parameter to ptp_parse_header()? >>>> >>>> It needs to read from the buffer, and in order to do that, it needs to >>>> validate that the buffer contains sufficient data. So, at minimum it >>>> needs to be a pointer and size of valid data. >>>> >>>> I was thinking about suggesting that as a core function, with a wrapper >>>> for the existing interface. >>>> >>> >>> Then length can be added. >> >> Actually, it needs more than that, because skb->data..skb->len already >> may contain the eth header or may not. >> >>> Otherwise not only CPTS can't benefit from this new API, but also >>> drivers like oki-semi/pch_gbe/pch_gbe_main.c -> pch_ptp_match() >> >> Again, this looks like it can be solved easily by swapping the position >> of these two calls: >> >> pch_rx_timestamp(adapter, skb); >> >> skb->protocol = eth_type_trans(skb, netdev); Sry, it will not be so "easily", because there is ptp_classify_raw() inside. So every such case, will require rework and adding magic like this __skb_push(skb, ETH_HLEN); type = ptp_classify_raw(skb); __skb_pull(skb, ETH_HLEN); in Hot path. >> >>> or have to two have two APIs (name?). >>> >>> ptp_parse_header1(struct sk_buff *skb, unsigned int type) >>> { >>> u8 *data = skb_mac_header(skb); >>> >>> ptp_parse_header2(struct sk_buff *skb, unsigned int type) >>> { >>> u8 *data = skb->data; >>> >>> everything else is the same. >> >> Actually, I really don't think we want 99% of users doing: >> >> hdr = ptp_parse_header(skb_mac_header(skb), skb->data, skb->len, type) >> >> or >> >> hdr = ptp_parse_header(skb_mac_header(skb), skb->data + skb->len, type); >> >> because that is what it will take, and this is starting to look >> really very horrid. > > True. > >> >> So, I repeat my question again: can netcp_core.c be adjusted to >> ensure that the skb mac header field is correctly set by calling >> eth_type_trans() prior to calling the rx hooks? The other two >> cpts cases look easy to change, and the oki-semi also looks the >> same. > > I think it's possible to adjust the netcp core. So, the time stamping is > done via > > gbe_rxhook() -> gbe_rxtstamp() -> cpts_rx_timestamp() > > The hooks are called in netcp_process_one_rx_packet(). So, moving > eth_type_trans() before executing the hooks should work. Only one hook > is registered. > > What do you think about it? I really do not want touch netcp, sry. There are other internal code based on this even if there is only one hooks in LKML now. + my comment above. I'll try use skb_reset_mac_header(skb); As spectrum does: skb_reset_mac_header(skb); mlxsw_sp1_ptp_got_packet(mlxsw_sp, skb, local_port, true); if doesn't help PATCH 6 is to drop. -- Best regards, grygorii
Powered by blists - more mailing lists