On 2/11/23 12:19 PM, 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.
Have you considered to implement a sockmap iterator? This will be similar to existing hash/array/sk_local_storage map iterators. The link below is the kernel implementation for sk_local_storage map iterator which iterates through all sockets. https://lore.kernel.org/bpf/20200723184116.590602-1-yhs@xxxxxx This way, in the future, if you want to print out more information from the socket, no kernel change is needed and you can just adjust your bpf program.
Cc: John Fastabend <john.fastabend@xxxxxxxxx> Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx> Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx> --- 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 | 49 ++++++++++++++++++++++++++++++++++ net/ipv4/inet_diag.c | 5 ++++ net/unix/diag.c | 6 +++++ 7 files changed, 71 insertions(+)
[...]
