diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2020-02-25 15:04:27 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-02-27 18:50:19 -0800 |
| commit | 085c20cacf2b72991ce1c9d99a5e2f1d9e73bb68 (patch) | |
| tree | c46fa77ecfc97e4120c02b7a8bd517e635afc7ee /include/linux/netlink.h | |
| parent | 1ed4d92458a969e71e7914550b6f0c730c14d84e (diff) | |
bpf: inet_diag: Dump bpf_sk_storages in inet_diag_dump()
This patch will dump out the bpf_sk_storages of a sk
if the request has the INET_DIAG_REQ_SK_BPF_STORAGES nlattr.
An array of SK_DIAG_BPF_STORAGE_REQ_MAP_FD can be specified in
INET_DIAG_REQ_SK_BPF_STORAGES to select which bpf_sk_storage to dump.
If no map_fd is specified, all bpf_sk_storages of a sk will be dumped.
bpf_sk_storages can be added to the system at runtime. It is difficult
to find a proper static value for cb->min_dump_alloc.
This patch learns the nlattr size required to dump the bpf_sk_storages
of a sk. If it happens to be the very first nlmsg of a dump and it
cannot fit the needed bpf_sk_storages, it will try to expand the
skb by "pskb_expand_head()".
Instead of expanding it in inet_sk_diag_fill(), it is expanded at a
sleepable context in __inet_diag_dump() so __GFP_DIRECT_RECLAIM can
be used. In __inet_diag_dump(), it will retry as long as the
skb is empty and the cb->min_dump_alloc becomes larger than before.
cb->min_dump_alloc is bounded by KMALLOC_MAX_SIZE. The min_dump_alloc
is also changed from 'u16' to 'u32' to accommodate a sk that may have
a few large bpf_sk_storages.
The updated cb->min_dump_alloc will also be used to allocate the skb in
the next dump. This logic already exists in netlink_dump().
Here is the sample output of a locally modified 'ss' and it could be made
more readable by using BTF later:
[root@arch-fb-vm1 ~]# ss --bpf-map-id 14 --bpf-map-id 13 -t6an 'dst [::1]:8989'
State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
ESTAB 0 0 [::1]:51072 [::1]:8989
bpf_map_id:14 value:[ 3feb ]
bpf_map_id:13 value:[ 3f ]
ESTAB 0 0 [::1]:51070 [::1]:8989
bpf_map_id:14 value:[ 3feb ]
bpf_map_id:13 value:[ 3f ]
[root@arch-fb-vm1 ~]# ~/devshare/github/iproute2/misc/ss --bpf-maps -t6an 'dst [::1]:8989'
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
ESTAB 0 0 [::1]:51072 [::1]:8989
bpf_map_id:14 value:[ 3feb ]
bpf_map_id:13 value:[ 3f ]
bpf_map_id:12 value:[ 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000... total:65407 ]
ESTAB 0 0 [::1]:51070 [::1]:8989
bpf_map_id:14 value:[ 3feb ]
bpf_map_id:13 value:[ 3f ]
bpf_map_id:12 value:[ 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000... total:65407 ]
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200225230427.1976129-1-kafai@fb.com
Diffstat (limited to 'include/linux/netlink.h')
| -rw-r--r-- | include/linux/netlink.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 205fa7b1f07a..788969ccbbde 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -188,10 +188,10 @@ struct netlink_callback { struct module *module; struct netlink_ext_ack *extack; u16 family; - u16 min_dump_alloc; - bool strict_check; u16 answer_flags; + u32 min_dump_alloc; unsigned int prev_seq, seq; + bool strict_check; union { u8 ctx[48]; |