From: Petr Machata <petrm@mellanox.com>
To: Kurt Kanzenbach <kurt@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>,
Andrew Lunn <andrew@lunn.ch>,
Vivien Didelot <vivien.didelot@gmail.com>,
Florian Fainelli <f.fainelli@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Jiri Pirko <jiri@mellanox.com>,
Ido Schimmel <idosch@mellanox.com>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
Samuel Zou <zou_wei@huawei.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2 4/9] mlxsw: spectrum_ptp: Use generic helper function
Date: Mon, 27 Jul 2020 15:00:10 +0200 [thread overview]
Message-ID: <87a6zli04l.fsf@mellanox.com> (raw)
In-Reply-To: <20200727090601.6500-5-kurt@linutronix.de>
Kurt Kanzenbach <kurt@linutronix.de> writes:
> @@ -329,30 +327,14 @@ static int mlxsw_sp_ptp_parse(struct sk_buff *skb,
> return -ERANGE;
> }
>
> - if (ptp_class & PTP_CLASS_VLAN)
> - offset += VLAN_HLEN;
> -
> - switch (ptp_class & PTP_CLASS_PMASK) {
> - case PTP_CLASS_IPV4:
> - offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
> - break;
> - case PTP_CLASS_IPV6:
> - offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
> - break;
> - case PTP_CLASS_L2:
> - offset += ETH_HLEN;
> - break;
> - default:
> - return -ERANGE;
> - }
> -
> - /* PTP header is 34 bytes. */
> - if (skb->len < offset + 34)
> + hdr = ptp_parse_header(skb, ptp_class);
> + if (!hdr)
> return -EINVAL;
So this looks good, and works, but I'm wondering about one thing.
Your code (and evidently most drivers as well) use a different check
than mlxsw, namely skb->len + ETH_HLEN < X. When I print_hex_dump()
skb_mac_header(skb), skb->len in mlxsw with some test packet, I get e.g.
this:
00000000259a4db7: 01 00 5e 00 01 81 00 02 c9 a4 e4 e1 08 00 45 00 ..^...........E.
000000005f29f0eb: 00 48 0d c9 40 00 01 11 c8 59 c0 00 02 01 e0 00 .H..@....Y......
00000000f3663e9e: 01 81 01 3f 01 3f 00 34 9f d3 00 02 00 2c 00 00 ...?.?.4.....,..
^sp^^ ^dp^^ ^len^ ^cks^ ^len^
00000000b3914606: 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 ................
000000002e7828ea: c9 ff fe a4 e4 e1 00 01 09 fa 00 00 00 00 00 00 ................
000000000b98156e: 00 00 00 00 00 00 ......
Both UDP and PTP length fields indicate that the payload ends exactly at
the end of the dump. So apparently skb->len contains all the payload
bytes, including the Ethernet header.
Is that the case for other drivers as well? Maybe mlxsw is just missing
some SKB magic in the driver.
next prev parent reply other threads:[~2020-07-27 13:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 9:05 [PATCH v2 0/9] ptp: Add generic header parsing function Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 1/9] ptp: Add generic ptp v2 " Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 2/9] ptp: Add generic ptp message type function Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 3/9] net: dsa: mv88e6xxx: Use generic helper function Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 4/9] mlxsw: spectrum_ptp: " Kurt Kanzenbach
2020-07-27 13:00 ` Petr Machata [this message]
2020-07-28 13:29 ` Kurt Kanzenbach
2020-07-28 13:41 ` Kurt Kanzenbach
2020-07-28 21:06 ` Petr Machata
2020-07-29 10:02 ` Russell King - ARM Linux admin
2020-07-29 10:29 ` Kurt Kanzenbach
2020-07-29 13:49 ` Richard Cochran
2020-07-29 14:26 ` Kurt Kanzenbach
2020-07-29 14:07 ` Petr Machata
2020-07-29 13:22 ` Richard Cochran
2020-07-29 12:23 ` Grygorii Strashko
2020-07-27 9:05 ` [PATCH v2 5/9] ethernet: ti: am65-cpts: " Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 6/9] ethernet: ti: cpts: " Kurt Kanzenbach
2020-07-27 9:05 ` [PATCH v2 7/9] net: phy: dp83640: " Kurt Kanzenbach
2020-07-27 9:06 ` [PATCH v2 8/9] ptp: ptp_ines: " Kurt Kanzenbach
2020-07-27 9:06 ` [PATCH v2 9/9] ptp: Remove unused macro Kurt Kanzenbach
2020-07-29 0:47 ` [PATCH v2 0/9] ptp: Add generic header parsing function David Miller
2020-07-29 9:31 ` Kurt Kanzenbach
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