[PATCH -next] af_packet: display drop field in packet_seq_show

[PATCH -next] af_packet: display drop field in packet_seq_show

[Liu Mingrui]

Display the dropped count of the packet, which could provide more
information for debugging.

Signed-off-by: Liu Mingrui <liumingrui@huawei.com>
---
 net/packet/af_packet.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4a364cdd445e..22c59ee61888 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4771,14 +4771,14 @@ static int packet_seq_show(struct seq_file *seq, void *v)
 {
 	if (v == SEQ_START_TOKEN)
 		seq_printf(seq,
-			   "%*sRefCnt Type Proto  Iface R Rmem   User   Inode\n",
+			   "%*sRefCnt Type Proto  Iface R Rmem   User   Inode   Drops\n",
 			   IS_ENABLED(CONFIG_64BIT) ? -17 : -9, "sk");
 	else {
 		struct sock *s = sk_entry(v);
 		const struct packet_sock *po = pkt_sk(s);
 
 		seq_printf(seq,
-			   "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
+			   "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu %u\n",
 			   s,
 			   refcount_read(&s->sk_refcnt),
 			   s->sk_type,
@@ -4787,7 +4787,8 @@ static int packet_seq_show(struct seq_file *seq, void *v)
 			   packet_sock_flag(po, PACKET_SOCK_RUNNING),
 			   atomic_read(&s->sk_rmem_alloc),
 			   from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
-			   sock_i_ino(s));
+			   sock_i_ino(s),
+			   atomic_read(&po->tp_drops));
 	}
 
 	return 0;
-- 
2.25.1

Re: [PATCH -next] af_packet: display drop field in packet_seq_show

[Eric Dumazet]

On Mon, Aug 26, 2024 at 3:26 AM Liu Mingrui <liumingrui@huawei.com> wrote:
>
> Display the dropped count of the packet, which could provide more
> information for debugging.
>
> Signed-off-by: Liu Mingrui <liumingrui@huawei.com>

Old /proc interface is legacy, we do not accept changes in it.

Instead, change net/packet/diag.c , iproute2/ss and use "ss -0".

Also, your patch is not correct, because of getsockopt( ...
PACKET_STATISTICS ... )

Re: [PATCH -next] af_packet: display drop field in packet_seq_show

[Stephen Hemminger]

On Mon, 26 Aug 2024 09:26:25 +0000
Liu Mingrui <liumingrui@huawei.com> wrote:

> Display the dropped count of the packet, which could provide more
> information for debugging.
> 
> Signed-off-by: Liu Mingrui <liumingrui@huawei.com>
> ---

At this point /proc/net/packet is a poor choice for extension.
For example, ss command ignores it if PACKET_DIAG_MEMINFO is available.

Better to add new netlink field see net/packet/diag.c.

Maybe time for PACKET_DIAG_STATS with name/value like ethtool.