bpf: add mrtt and srtt as BPF_SOCK_OPS_RTT_CB args

Two important arguments in RTT estimation, mrtt and srtt, are passed to tcp_bpf_rtt(), so that bpf programs get more information about RTT computation in BPF_SOCK_OPS_RTT_CB. The difference between bpf_sock_ops->srtt_us and the srtt here is: the former is an old rtt before update, while srtt passed by tcp_bpf_rtt() is that after update.

Philo Lu committed 2 years ago

Commit 48e2cd31 parent a311c3f4 files · +8 −4Browse files

Unified · Split

4 files

include/net/tcp.h +2 −2
include/uapi/linux/bpf.h +2 −0
net/ipv4/tcp_input.c +2 −2
tools/include/uapi/linux/bpf.h +2 −0

include/net/tcp.h+2−2

@@ -2706,10 +2706,10 @@ static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk) · 2705 unmodified lines
2706	2706	return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);
2707	2707	}
2708	2708
2709		−static inline void tcp_bpf_rtt(struct sock *sk)
	2709	+static inline void tcp_bpf_rtt(struct sock *sk, long mrtt, u32 srtt)
2710	2710	{
2711	2711	if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG))
2712		− tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL);
	2712	+ tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_RTT_CB, mrtt, srtt);
2713	2713	}
2714	2714
2715	2715	#if IS_ENABLED(CONFIG_SMC)

include/uapi/linux/bpf.h+2−0

@@ -6947,6 +6947,8 @@ enum { · 6946 unmodified lines
6947	6947	* socket transition to LISTEN state.
6948	6948	*/
6949	6949	BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
	6950	+ * Arg1: measured RTT input (mrtt)
	6951	+ * Arg2: updated srtt
6950	6952	*/
6951	6953	BPF_SOCK_OPS_PARSE_HDR_OPT_CB, /* Parse the header option.
6952	6954	* It will be called to handle

net/ipv4/tcp_input.c+2−2

@@ -911,7 +911,7 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us) · 910 unmodified lines
911	911	tp->rtt_seq = tp->snd_nxt;
912	912	tp->mdev_max_us = tcp_rto_min_us(sk);
913	913
914		− tcp_bpf_rtt(sk);
	914	+ tcp_bpf_rtt(sk, mrtt_us, srtt);
915	915	}
916	916	} else {
917	917	/* no previous measure. */
@@ -921,7 +921,7 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us) · 3 unmodified lines
921	921	tp->mdev_max_us = tp->rttvar_us;
922	922	tp->rtt_seq = tp->snd_nxt;
923	923
924		− tcp_bpf_rtt(sk);
	924	+ tcp_bpf_rtt(sk, mrtt_us, srtt);
925	925	}
926	926	tp->srtt_us = max(1U, srtt);
927	927	}

tools/include/uapi/linux/bpf.h+2−0

@@ -6947,6 +6947,8 @@ enum { · 6946 unmodified lines
6947	6947	* socket transition to LISTEN state.
6948	6948	*/
6949	6949	BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
	6950	+ * Arg1: measured RTT input (mrtt)
	6951	+ * Arg2: updated srtt
6950	6952	*/
6951	6953	BPF_SOCK_OPS_PARSE_HDR_OPT_CB, /* Parse the header option.
6952	6954	* It will be called to handle