leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

sock: make cookie generation global instead of per netns

Browse Source 
Generating and retrieving socket cookies are a useful feature that is
exposed to BPF for various program types through bpf_get_socket_cookie()
helper.

The fact that the cookie counter is per netns is quite a limitation
for BPF in practice in particular for programs in host namespace that
use socket cookies as part of a map lookup key since they will be
causing socket cookie collisions e.g. when attached to BPF cgroup hooks
or cls_bpf on tc egress in host namespace handling container traffic
from veth or ipvlan devices with peer in different netns. Change the
counter to be global instead.

Socket cookie consumers must assume the value as opqaue in any case.
Not every socket must have a cookie generated and knowledge of the
counter value itself does not provide much value either way hence
conversion to global is fine.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Martynas Pumputis <m@lambda.lt>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2019-08-08 13:57:25 +02:00 committed by David S. Miller
parent 7bac762d8d
commit cd48bdda4f
3 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/net_namespace.h
View File

@ -61,7 +61,6 @@ struct net {
spinlock_t rules_mod_lock;
u32 hash_mix;
atomic64_t cookie_gen;
struct list_head list; /* list of network namespaces */
struct list_head exit_list; /* To linked to call pernet exit

4
include/uapi/linux/bpf.h
View File

@ -1466,8 +1466,8 @@ union bpf_attr {
* If no cookie has been set yet, generate a new cookie. Once
* generated, the socket cookie remains stable for the life of the
* socket. This helper can be useful for monitoring per socket
* networking traffic statistics as it provides a unique socket
* identifier per namespace.
* networking traffic statistics as it provides a global socket
* identifier that can be assumed unique.
* Return
* A 8-byte long non-decreasing number on success, or 0 if the
* socket field is missing inside *skb*.

3
net/core/sock_diag.c
View File

@ -19,6 +19,7 @@ static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
static DEFINE_MUTEX(sock_diag_table_mutex);
static struct workqueue_struct *broadcast_wq;
static atomic64_t cookie_gen;
u64 sock_gen_cookie(struct sock *sk)
{
@ -27,7 +28,7 @@ u64 sock_gen_cookie(struct sock *sk)
if (res)
return res;
res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
res = atomic64_inc_return(&cookie_gen);
atomic64_cmpxchg(&sk->sk_cookie, 0, res);
}
}