The _bpf_setsockopt() is able to set some of the SOL_SOCKET level options,
however, _bpf_getsockopt() has little support to actually retrieve them.
This small patch adds few misc options such as SO_MARK, SO_PRIORITY and
SO_BINDTOIFINDEX. For the latter getter and setter are added. The mark and
priority in particular allow to retrieve the options from BPF cgroup hooks
to then implement custom behavior / settings on the syscall hooks compared
to other sockets that stick to the defaults, for example.
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
---
net/core/filter.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 255aeee72402..9ab94e90d660 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4770,6 +4770,10 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
ifindex = dev->ifindex;
dev_put(dev);
}
+ fallthrough;
+ case SO_BINDTOIFINDEX:
+ if (optname == SO_BINDTOIFINDEX)
+ ifindex = val;
ret = sock_bindtoindex(sk, ifindex, false);
break;
case SO_KEEPALIVE:
@@ -4932,8 +4936,25 @@ static int _bpf_getsockopt(struct sock *sk, int level, int optname,
sock_owned_by_me(sk);
+ if (level == SOL_SOCKET) {
+ if (optlen != sizeof(int))
+ goto err_clear;
+
+ switch (optname) {
+ case SO_MARK:
+ *((int *)optval) = sk->sk_mark;
+ break;
+ case SO_PRIORITY:
+ *((int *)optval) = sk->sk_priority;
+ break;
+ case SO_BINDTOIFINDEX:
+ *((int *)optval) = sk->sk_bound_dev_if;
+ break;
+ default:
+ goto err_clear;
+ }
#ifdef CONFIG_INET
- if (level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) {
+ } else if (level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) {
struct inet_connection_sock *icsk;
struct tcp_sock *tp;
@@ -4986,12 +5007,12 @@ static int _bpf_getsockopt(struct sock *sk, int level, int optname,
default:
goto err_clear;
}
+#endif
#endif
} else {
goto err_clear;
}
return 0;
-#endif
err_clear:
memset(optval, 0, optlen);
return -EINVAL;
--
2.21.0
