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ptp: Add generic ptp v2 header parsing function 

Reason: A lot of the ptp drivers - which implement hardware time stamping - need
specific fields such as the sequence id from the ptp v2 header. Currently all
drivers implement that themselves.

Introduce a generic function to retrieve a pointer to the start of the ptp v2
header.

Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kurt Kanzenbach 2020-08-18 12:32:43 +02:00 committed by David S. Miller
parent f3ae59c0c0
commit bdfbb63c31
2 changed files with 74 additions and 0 deletions
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44
include/linux/ptp_classify.h
View File

@ -44,6 +44,30 @@
#define OFF_IHL 14
#define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
struct clock_identity {
u8 id[8];
} __packed;
struct port_identity {
struct clock_identity clock_identity;
__be16 port_number;
} __packed;
struct ptp_header {
u8 tsmt; /* transportSpecific | messageType */
u8 ver; /* reserved | versionPTP */
__be16 message_length;
u8 domain_number;
u8 reserved1;
u8 flag_field[2];
__be64 correction;
__be32 reserved2;
struct port_identity source_port_identity;
__be16 sequence_id;
u8 control;
u8 log_message_interval;
} __packed;
#if defined(CONFIG_NET_PTP_CLASSIFY)
/**
* ptp_classify_raw - classify a PTP packet
@ -57,6 +81,21 @@
*/
unsigned int ptp_classify_raw(const struct sk_buff *skb);
/**
* ptp_parse_header - Get pointer to the PTP v2 header
* @skb: packet buffer
* @type: type of the packet (see ptp_classify_raw())
*
* This function takes care of the VLAN, UDP, IPv4 and IPv6 headers. The length
* is checked.
*
* Note, internally skb_mac_header() is used. Make sure that the @skb is
* initialized accordingly.
*
* Return: Pointer to the ptp v2 header or NULL if not found
*/
struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type);
void __init ptp_classifier_init(void);
#else
static inline void ptp_classifier_init(void)
@ -66,5 +105,10 @@ static inline unsigned int ptp_classify_raw(struct sk_buff *skb)
{
return PTP_CLASS_NONE;
}
static inline struct ptp_header *ptp_parse_header(struct sk_buff *skb,
unsigned int type)
{
return NULL;
}
#endif
#endif /* _PTP_CLASSIFY_H_ */

30
net/core/ptp_classifier.c
View File

@ -107,6 +107,36 @@ 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 *ptr = skb_mac_header(skb);
if (type & PTP_CLASS_VLAN)
ptr += VLAN_HLEN;
switch (type & PTP_CLASS_PMASK) {
case PTP_CLASS_IPV4:
ptr += IPV4_HLEN(ptr) + UDP_HLEN;
break;
case PTP_CLASS_IPV6:
ptr += IP6_HLEN + UDP_HLEN;
break;
case PTP_CLASS_L2:
break;
default:
return NULL;
}
ptr += ETH_HLEN;
/* Ensure that the entire header is present in this packet. */
if (ptr + sizeof(struct ptp_header) > skb->data + skb->len)
return NULL;
return (struct ptp_header *)ptr;
}
EXPORT_SYMBOL_GPL(ptp_parse_header);
void __init ptp_classifier_init(void)
{
static struct sock_filter ptp_filter[] __initdata = {