diff options
Diffstat (limited to 'net/core/filter.c')
| -rw-r--r-- | net/core/filter.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 96f2f7a65e65..ac4c45c02da5 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5105,6 +5105,9 @@ static int bpf_sol_tcp_setsockopt(struct sock *sk, int optname, static int sol_tcp_sockopt_congestion(struct sock *sk, char *optval, int *optlen, bool getopt) { + struct tcp_sock *tp; + int ret; + if (*optlen < 2) return -EINVAL; @@ -5125,8 +5128,31 @@ static int sol_tcp_sockopt_congestion(struct sock *sk, char *optval, if (*optlen >= sizeof("cdg") - 1 && !strncmp("cdg", optval, *optlen)) return -ENOTSUPP; - return do_tcp_setsockopt(sk, SOL_TCP, TCP_CONGESTION, + /* It stops this looping + * + * .init => bpf_setsockopt(tcp_cc) => .init => + * bpf_setsockopt(tcp_cc)" => .init => .... + * + * The second bpf_setsockopt(tcp_cc) is not allowed + * in order to break the loop when both .init + * are the same bpf prog. + * + * This applies even the second bpf_setsockopt(tcp_cc) + * does not cause a loop. This limits only the first + * '.init' can call bpf_setsockopt(TCP_CONGESTION) to + * pick a fallback cc (eg. peer does not support ECN) + * and the second '.init' cannot fallback to + * another. + */ + tp = tcp_sk(sk); + if (tp->bpf_chg_cc_inprogress) + return -EBUSY; + + tp->bpf_chg_cc_inprogress = 1; + ret = do_tcp_setsockopt(sk, SOL_TCP, TCP_CONGESTION, KERNEL_SOCKPTR(optval), *optlen); + tp->bpf_chg_cc_inprogress = 0; + return ret; } static int sol_tcp_sockopt(struct sock *sk, int optname, |