Commit 37cfbe0b authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: Move the "cdg" tcp-cc check to the common sol_tcp_sockopt() 



The check on the tcp-cc, "cdg", is done in the bpf_sk_setsockopt which is
used by the bpf_tcp_ca, bpf_lsm, cg_sockopt, and tcp_iter hooks.
However, it is not done for cg sock_ddr, cg sockops, and some of
the bpf_lsm_cgroup hooks.

The tcp-cc "cdg" should have very limited usage.  This patch is to
move the "cdg" check to the common sol_tcp_sockopt() so that all
hooks have a consistent behavior.   The motivation to make
this check consistent now is because the latter patch will
refactor the bpf_setsockopt(TCP_CONGESTION) into another function,
so it is better to take this chance to refactor this piece
also.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-3-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 64696c40

net/core/filter.c

+7 −6
Original line number Diff line number Diff line
@@ -5127,6 +5127,13 @@ static int sol_tcp_sockopt(struct sock *sk, int optname, 
	case TCP_CONGESTION:

		if (*optlen < 2)

			return -EINVAL;

		/* "cdg" is the only cc that alloc a ptr

		 * in inet_csk_ca area.  The bpf-tcp-cc may

		 * overwrite this ptr after switching to cdg.

		 */

		if (!getopt && *optlen >= sizeof("cdg") - 1 &&

		    !strncmp("cdg", optval, *optlen))

			return -ENOTSUPP;

		break;

	case TCP_SAVED_SYN:

		if (*optlen < 1)
@@ -5285,12 +5292,6 @@ static int _bpf_getsockopt(struct sock *sk, int level, int optname, 
BPF_CALL_5(bpf_sk_setsockopt, struct sock *, sk, int, level,

	   int, optname, char *, optval, int, optlen)

{

	if (level == SOL_TCP && optname == TCP_CONGESTION) {

		if (optlen >= sizeof("cdg") - 1 &&

		    !strncmp("cdg", optval, optlen))

			return -ENOTSUPP;

	}



	return _bpf_setsockopt(sk, level, optname, optval, optlen);

}