[PATCH bpf-next v2 1/2] bpf: allow to retrieve sol_socket opts from sock_addr progs
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2021-01-12 00:30:39
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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@iogearbox.net> Acked-by: Yonghong Song <redacted> --- 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