Commit 8b52cc2a authored by Martin KaFai Lau's avatar Martin KaFai Lau
Browse files

Merge branch 'Allow BPF TCP CCs to write app_limited' 



Yixin Shen says:

====================

This series allow BPF TCP CCs to write app_limited of struct
tcp_sock. A built-in CC or one from a kernel module is already
able to write to app_limited of struct tcp_sock. Until now,
a BPF CC doesn't have write access to this member of struct
tcp_sock.

v2:
 - Merge the test of writing app_limited into the test of
   writing sk_pacing. (Martin KaFai Lau)
====================

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parents d8d8b008 4239561b

net/ipv4/bpf_tcp_ca.c

+3 −0
Original line number Diff line number Diff line
@@ -113,6 +113,9 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, 
	case offsetof(struct tcp_sock, ecn_flags):

		end = offsetofend(struct tcp_sock, ecn_flags);

		break;

	case offsetof(struct tcp_sock, app_limited):

		end = offsetofend(struct tcp_sock, app_limited);

		break;

	default:

		bpf_log(log, "no write support to tcp_sock at off %d\n", off);

		return -EACCES;

tools/testing/selftests/bpf/progs/tcp_ca_write_sk_pacing.c

+12 −1
Original line number Diff line number Diff line
@@ -16,6 +16,16 @@ static inline struct tcp_sock *tcp_sk(const struct sock *sk) 
	return (struct tcp_sock *)sk;

}



static inline unsigned int tcp_left_out(const struct tcp_sock *tp)

{

	return tp->sacked_out + tp->lost_out;

}



static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)

{

	return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;

}



SEC("struct_ops/write_sk_pacing_init")

void BPF_PROG(write_sk_pacing_init, struct sock *sk)

{
@@ -31,11 +41,12 @@ SEC("struct_ops/write_sk_pacing_cong_control") 
void BPF_PROG(write_sk_pacing_cong_control, struct sock *sk,

	      const struct rate_sample *rs)

{

	const struct tcp_sock *tp = tcp_sk(sk);

	struct tcp_sock *tp = tcp_sk(sk);

	unsigned long rate =

		((tp->snd_cwnd * tp->mss_cache * USEC_PER_SEC) << 3) /

		(tp->srtt_us ?: 1U << 3);

	sk->sk_pacing_rate = min(rate, sk->sk_max_pacing_rate);

	tp->app_limited = (tp->delivered + tcp_packets_in_flight(tp)) ?: 1;

}



SEC("struct_ops/write_sk_pacing_ssthresh")