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sock_map: Lift socket state restriction for datagram sockets

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TCP and other connection oriented sockets have accept()
for each incoming connection on the server side, hence
they can just insert those fd's from accept() to sockmap,
which are of course established.

Now with datagram sockets begin to support sockmap and
redirection, the restriction is no longer applicable to
them, as they have no accept(). So we have to lift this
restriction for them. This is fine, because inside
bpf_sk_redirect_map() we still have another socket status
check, sock_map_redirect_allowed(), as a guard.

This also means they do not have to be removed from
sockmap when disconnecting.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-3-xiyou.wangcong@gmail.com
This commit is contained in:
Cong Wang 2021-07-04 12:02:43 -07:00 committed by Alexei Starovoitov
parent 17edea21b3
commit 0c48eefae7
3 changed files with 6 additions and 24 deletions
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21
net/core/sock_map.c
View file

@ -211,8 +211,6 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
return psock;
}
static bool sock_map_redirect_allowed(const struct sock *sk);
static int sock_map_link(struct bpf_map *map, struct sock *sk)
{
struct sk_psock_progs *progs = sock_map_progs(map);
@ -223,13 +221,6 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
struct sk_psock *psock;
int ret;
/* Only sockets we can redirect into/from in BPF need to hold
* refs to parser/verdict progs and have their sk_data_ready
* and sk_write_space callbacks overridden.
*/
if (!sock_map_redirect_allowed(sk))
goto no_progs;
stream_verdict = READ_ONCE(progs->stream_verdict);
if (stream_verdict) {
stream_verdict = bpf_prog_inc_not_zero(stream_verdict);
@ -264,7 +255,6 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
}
}
no_progs:
psock = sock_map_psock_get_checked(sk);
if (IS_ERR(psock)) {
ret = PTR_ERR(psock);
@ -527,12 +517,6 @@ static bool sk_is_tcp(const struct sock *sk)
sk->sk_protocol == IPPROTO_TCP;
}
static bool sk_is_udp(const struct sock *sk)
{
return sk->sk_type == SOCK_DGRAM &&
sk->sk_protocol == IPPROTO_UDP;
}
static bool sock_map_redirect_allowed(const struct sock *sk)
{
if (sk_is_tcp(sk))
@ -550,10 +534,7 @@ static bool sock_map_sk_state_allowed(const struct sock *sk)
{
if (sk_is_tcp(sk))
return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
else if (sk_is_udp(sk))
return sk_hashed(sk);
return false;
return true;
}
static int sock_hash_update_common(struct bpf_map *map, void *key,

1
net/ipv4/udp_bpf.c
View file

@ -112,7 +112,6 @@ static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
{
*prot = *base;
prot->unhash = sock_map_unhash;
prot->close = sock_map_close;
prot->recvmsg = udp_bpf_recvmsg;
}

8
tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
View file

@ -351,9 +351,11 @@ static void test_insert_opened(int family, int sotype, int mapfd)
errno = 0;
value = s;
err = bpf_map_update_elem(mapfd, &key, &value, BPF_NOEXIST);
if (!err || errno != EOPNOTSUPP)
FAIL_ERRNO("map_update: expected EOPNOTSUPP");
if (sotype == SOCK_STREAM) {
if (!err || errno != EOPNOTSUPP)
FAIL_ERRNO("map_update: expected EOPNOTSUPP");
} else if (err)
FAIL_ERRNO("map_update: expected success");
xclose(s);
}