Cong Wang wrote:
> From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
>
> Currently there is no way to know which sockmap a socket has been added
> to from outside, especially for that a socket can be added to multiple
> sockmap's. We could dump this via socket diag, as shown below.
>
> Sample output:
>
> # ./iproute2/misc/ss -tnaie --sockmap
> ESTAB 0 344329 127.0.0.1:1234 127.0.0.1:40912 ino:21098 sk:5 cgroup:/user.slice/user-0.slice/session-c1.scope <-> sockmap: 1
>
> # bpftool map
> 1: sockmap flags 0x0
> key 4B value 4B max_entries 2 memlock 4096B
> pids echo-sockmap(549)
> 4: array name pid_iter.rodata flags 0x480
> key 4B value 4B max_entries 1 memlock 4096B
> btf_id 10 frozen
> pids bpftool(624)
>
> In the future, we could dump other sockmap related stats too, hence I
> make it a nested attribute.
>
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
> Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
> ---
> v2: rename enum's with more generic names
> sock_map_idiag_dump -> sock_map_diag_dump()
> make sock_map_diag_dump() return number of maps
>
> include/linux/bpf.h | 1 +
> include/uapi/linux/inet_diag.h | 1 +
> include/uapi/linux/sock_diag.h | 8 ++++++
> include/uapi/linux/unix_diag.h | 1 +
> net/core/sock_map.c | 51 ++++++++++++++++++++++++++++++++++
> net/ipv4/inet_diag.c | 5 ++++
> net/unix/diag.c | 6 ++++
> 7 files changed, 73 insertions(+)
>
[...]
> +int sock_map_diag_dump(struct sock *sk, struct sk_buff *skb, int attrtype)
> +{
> + struct sk_psock_link *link;
> + struct nlattr *nla, *attr;
> + int nr_links = 0, ret = 0;
> + struct sk_psock *psock;
> + u32 *ids;
> +
> + rcu_read_lock();
> + psock = sk_psock_get(sk);
> + if (unlikely(!psock)) {
wont this be the common case because we call this for any sk from
inet_diag_msg_attrs_fill(sk, ...)? Probably drop the unlikely?
> + rcu_read_unlock();
> + return 0;
> + }
