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linux-next/include/linux/ptp_classify.h
Daniel Borkmann 408eccce32 net: ptp: move PTP classifier in its own file
This commit fixes a build error reported by Fengguang, that is
triggered when CONFIG_NETWORK_PHY_TIMESTAMPING is not set:

  ERROR: "ptp_classify_raw" [drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe.ko] undefined!

The fix is to introduce its own file for the PTP BPF classifier,
so that PTP_1588_CLOCK and/or NETWORK_PHY_TIMESTAMPING can select
it independently from each other. IXP4xx driver on ARM needs to
select it as well since it does not seem to select PTP_1588_CLOCK
or similar that would pull it in automatically.

This also allows for hiding all of the internals of the BPF PTP
program inside that file, and only exporting relevant API bits
to drivers.

This patch also adds a kdoc documentation of ptp_classify_raw()
API to make it clear that it can return PTP_CLASS_* defines. Also,
the BPF program has been translated into bpf_asm code, so that it
can be more easily read and altered (extensively documented in [1]).

In the kernel tree under tools/net/ we have bpf_asm and bpf_dbg
tools, so the commented program can simply be translated via
`./bpf_asm -c prog` where prog is a file that contains the
commented code. This makes it easily readable/verifiable and when
there's a need to change something, jump offsets etc do not need
to be replaced manually which can be very error prone. Instead,
a newly translated version via bpf_asm can simply replace the old
code. I have checked opcode diffs before/after and it's the very
same filter.

  [1] Documentation/networking/filter.txt

Fixes: 164d8c6665 ("net: ptp: do not reimplement PTP/BPF classifier")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Jiri Benc <jbenc@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-01 16:43:18 -04:00

80 lines
2.9 KiB
C

/*
* PTP 1588 support
*
* This file implements a BPF that recognizes PTP event messages.
*
* Copyright (C) 2010 OMICRON electronics GmbH
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _PTP_CLASSIFY_H_
#define _PTP_CLASSIFY_H_
#include <linux/ip.h>
#include <linux/skbuff.h>
#define PTP_CLASS_NONE 0x00 /* not a PTP event message */
#define PTP_CLASS_V1 0x01 /* protocol version 1 */
#define PTP_CLASS_V2 0x02 /* protocol version 2 */
#define PTP_CLASS_VMASK 0x0f /* max protocol version is 15 */
#define PTP_CLASS_IPV4 0x10 /* event in an IPV4 UDP packet */
#define PTP_CLASS_IPV6 0x20 /* event in an IPV6 UDP packet */
#define PTP_CLASS_L2 0x30 /* event in a L2 packet */
#define PTP_CLASS_VLAN 0x40 /* event in a VLAN tagged L2 packet */
#define PTP_CLASS_PMASK 0xf0 /* mask for the packet type field */
#define PTP_CLASS_V1_IPV4 (PTP_CLASS_V1 | PTP_CLASS_IPV4)
#define PTP_CLASS_V1_IPV6 (PTP_CLASS_V1 | PTP_CLASS_IPV6) /* probably DNE */
#define PTP_CLASS_V2_IPV4 (PTP_CLASS_V2 | PTP_CLASS_IPV4)
#define PTP_CLASS_V2_IPV6 (PTP_CLASS_V2 | PTP_CLASS_IPV6)
#define PTP_CLASS_V2_L2 (PTP_CLASS_V2 | PTP_CLASS_L2)
#define PTP_CLASS_V2_VLAN (PTP_CLASS_V2 | PTP_CLASS_VLAN)
#define PTP_EV_PORT 319
#define PTP_GEN_BIT 0x08 /* indicates general message, if set in message type */
#define OFF_PTP_SOURCE_UUID 22 /* PTPv1 only */
#define OFF_PTP_SEQUENCE_ID 30
#define OFF_PTP_CONTROL 32 /* PTPv1 only */
/* Below defines should actually be removed at some point in time. */
#define IP6_HLEN 40
#define UDP_HLEN 8
#define OFF_IHL 14
#define OFF_PTP6 (ETH_HLEN + IP6_HLEN + UDP_HLEN)
#define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
#if defined(CONFIG_NET_PTP_CLASSIFY)
/**
* ptp_classify_raw - classify a PTP packet
* @skb: buffer
*
* Runs a minimal BPF dissector to classify a network packet to
* determine the PTP class. In case the skb does not contain any
* PTP protocol data, PTP_CLASS_NONE will be returned, otherwise
* PTP_CLASS_V1_IPV{4,6}, PTP_CLASS_V2_IPV{4,6} or
* PTP_CLASS_V2_{L2,VLAN}, depending on the packet content.
*/
unsigned int ptp_classify_raw(const struct sk_buff *skb);
void __init ptp_classifier_init(void);
#else
static inline void ptp_classifier_init(void)
{
}
#endif
#endif /* _PTP_CLASSIFY_H_ */