On Tue, Feb 14, 2023 at 2:17 PM Kui-Feng Lee <kuifeng@xxxxxxxx> wrote:
>
> Create a pair of sockets that utilize the congestion control algorithm
> under a particular name. Then switch up this congestion control
> algorithm to another implementation and check whether newly created
> connections using the same cc name now run the new implementation.
>
> Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/bpf_tcp_ca.c | 48 ++++++++++++
> .../selftests/bpf/progs/tcp_ca_update.c | 75 +++++++++++++++++++
> 2 files changed, 123 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/tcp_ca_update.c
>
[...]
> diff --git a/tools/testing/selftests/bpf/progs/tcp_ca_update.c b/tools/testing/selftests/bpf/progs/tcp_ca_update.c
> new file mode 100644
> index 000000000000..cf51fe54ac01
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/tcp_ca_update.c
> @@ -0,0 +1,75 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include "vmlinux.h"
> +
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +
> +char _license[] SEC("license") = "GPL";
> +
> +int ca1_cnt = 0;
> +int ca2_cnt = 0;
> +
> +#define USEC_PER_SEC 1000000UL
> +
> +#define min(a, b) ((a) < (b) ? (a) : (b))
> +
> +static inline struct tcp_sock *tcp_sk(const struct sock *sk)
> +{
> + return (struct tcp_sock *)sk;
> +}
> +
> +SEC("struct_ops/ca_update_init")
> +void BPF_PROG(ca_update_init, struct sock *sk)
> +{
> +#ifdef ENABLE_ATOMICS_TESTS
it's been 2 years since atomics were added to Clang, I think it's fine
to just assume atomic operations are supported and not do the
ENABLE_ATOMICS_TEST (and I'd clean up ENABLE_ATOMICS_TESTS now as
well)
> + __sync_bool_compare_and_swap(&sk->sk_pacing_status, SK_PACING_NONE,
> + SK_PACING_NEEDED);
> +#else
> + sk->sk_pacing_status = SK_PACING_NEEDED;
> +#endif
> +}
> +
> +SEC("struct_ops/ca_update_1_cong_control")
> +void BPF_PROG(ca_update_1_cong_control, struct sock *sk,
> + const struct rate_sample *rs)
> +{
> + ca1_cnt++;
> +}
> +
> +SEC("struct_ops/ca_update_2_cong_control")
> +void BPF_PROG(ca_update_2_cong_control, struct sock *sk,
> + const struct rate_sample *rs)
> +{
> + ca2_cnt++;
> +}
> +
> +SEC("struct_ops/ca_update_ssthresh")
> +__u32 BPF_PROG(ca_update_ssthresh, struct sock *sk)
> +{
> + return tcp_sk(sk)->snd_ssthresh;
> +}
> +
> +SEC("struct_ops/ca_update_undo_cwnd")
> +__u32 BPF_PROG(ca_update_undo_cwnd, struct sock *sk)
> +{
> + return tcp_sk(sk)->snd_cwnd;
> +}
> +
> +SEC(".struct_ops")
> +struct tcp_congestion_ops ca_update_1 = {
> + .init = (void *)ca_update_init,
> + .cong_control = (void *)ca_update_1_cong_control,
> + .ssthresh = (void *)ca_update_ssthresh,
> + .undo_cwnd = (void *)ca_update_undo_cwnd,
> + .name = "tcp_ca_update",
> +};
> +
> +SEC(".struct_ops")
> +struct tcp_congestion_ops ca_update_2 = {
> + .init = (void *)ca_update_init,
> + .cong_control = (void *)ca_update_2_cong_control,
> + .ssthresh = (void *)ca_update_ssthresh,
> + .undo_cwnd = (void *)ca_update_undo_cwnd,
> + .name = "tcp_ca_update",
> +};
> --
> 2.30.2
>
