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psample: Add additional metadata attributes
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Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a 64-bit value
* End-to-end latency of the packet in nanoseconds resolution
* Software timestamp in nanoseconds resolution (always available)
* Packet's protocol. Needed for packet dissection in user space (always
  available)

Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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idosch authored and davem330 committed Mar 14, 2021
1 parent a03e99d commit 07e1a58
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Showing 3 changed files with 52 additions and 1 deletion.
7 changes: 7 additions & 0 deletions include/net/psample.h
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,13 @@ struct psample_metadata {
u32 trunc_size;
int in_ifindex;
int out_ifindex;
u16 out_tc;
u64 out_tc_occ; /* bytes */
u64 latency; /* nanoseconds */
u8 out_tc_valid:1,
out_tc_occ_valid:1,
latency_valid:1,
unused:5;
};

struct psample_group *psample_group_get(struct net *net, u32 group_num);
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7 changes: 7 additions & 0 deletions include/uapi/linux/psample.h
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,13 @@ enum {
/* commands attributes */
PSAMPLE_ATTR_GROUP_REFCOUNT,

PSAMPLE_ATTR_PAD,
PSAMPLE_ATTR_OUT_TC, /* u16 */
PSAMPLE_ATTR_OUT_TC_OCC, /* u64, bytes */
PSAMPLE_ATTR_LATENCY, /* u64, nanoseconds */
PSAMPLE_ATTR_TIMESTAMP, /* u64, nanoseconds */
PSAMPLE_ATTR_PROTO, /* u16 */

__PSAMPLE_ATTR_MAX
};

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39 changes: 38 additions & 1 deletion net/psample/psample.c
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <linux/timekeeping.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
Expand Down Expand Up @@ -358,6 +359,7 @@ static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
u32 sample_rate, const struct psample_metadata *md)
{
ktime_t tstamp = ktime_get_real();
int out_ifindex = md->out_ifindex;
int in_ifindex = md->in_ifindex;
u32 trunc_size = md->trunc_size;
Expand All @@ -372,10 +374,15 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,

meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
(out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
(md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +
(md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
(md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
nla_total_size(sizeof(u32)) + /* sample_rate */
nla_total_size(sizeof(u32)) + /* orig_size */
nla_total_size(sizeof(u32)) + /* group_num */
nla_total_size(sizeof(u32)); /* seq */
nla_total_size(sizeof(u32)) + /* seq */
nla_total_size_64bit(sizeof(u64)) + /* timestamp */
nla_total_size(sizeof(u16)); /* protocol */

#ifdef CONFIG_INET
tun_info = skb_tunnel_info(skb);
Expand Down Expand Up @@ -425,6 +432,36 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
if (unlikely(ret < 0))
goto error;

if (md->out_tc_valid) {
ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc);
if (unlikely(ret < 0))
goto error;
}

if (md->out_tc_occ_valid) {
ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC,
md->out_tc_occ, PSAMPLE_ATTR_PAD);
if (unlikely(ret < 0))
goto error;
}

if (md->latency_valid) {
ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY,
md->latency, PSAMPLE_ATTR_PAD);
if (unlikely(ret < 0))
goto error;
}

ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP,
ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD);
if (unlikely(ret < 0))
goto error;

ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO,
be16_to_cpu(skb->protocol));
if (unlikely(ret < 0))
goto error;

if (data_len) {
int nla_len = nla_total_size(data_len);
struct nlattr *nla;
Expand Down

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