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.

Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240425161724.73707-2-lulie@linux.alibaba.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6ae35199d3b3c159ba029ff74b109c56a7c7d2fc..0f75d03287c25d964e3f3db53e8041b7bc75d018 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2706,10 +2706,10 @@ static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk)
        return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);
 }
 
-static inline void tcp_bpf_rtt(struct sock *sk)
+static inline void tcp_bpf_rtt(struct sock *sk, long mrtt, u32 srtt)
 {
        if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG))
-               tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL);
+               tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_RTT_CB, mrtt, srtt);
 }
 
 #if IS_ENABLED(CONFIG_SMC)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e4ae83550fb39c39149d269805628ee4d96dca44..d94a72593ead2788964a658336be4c313b097873 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6947,6 +6947,8 @@ enum {
                                         * socket transition to LISTEN state.
                                         */
        BPF_SOCK_OPS_RTT_CB,            /* Called on every RTT.
+                                        * Arg1: measured RTT input (mrtt)
+                                        * Arg2: updated srtt
                                         */
        BPF_SOCK_OPS_PARSE_HDR_OPT_CB,  /* Parse the header option.
                                         * It will be called to handle

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 5d874817a78db31a4a807ab80e9158300329423d..d1115d7c3936aa86ecdaa396395104bcca652a9a 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -911,7 +911,7 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us)
                        tp->rtt_seq = tp->snd_nxt;
                        tp->mdev_max_us = tcp_rto_min_us(sk);
 
-                       tcp_bpf_rtt(sk);
+                       tcp_bpf_rtt(sk, mrtt_us, srtt);
                }
        } else {
                /* no previous measure. */
@@ -921,7 +921,7 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us)
                tp->mdev_max_us = tp->rttvar_us;
                tp->rtt_seq = tp->snd_nxt;
 
-               tcp_bpf_rtt(sk);
+               tcp_bpf_rtt(sk, mrtt_us, srtt);
        }
        tp->srtt_us = max(1U, srtt);
 }

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e4ae83550fb39c39149d269805628ee4d96dca44..d94a72593ead2788964a658336be4c313b097873 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6947,6 +6947,8 @@ enum {
                                         * socket transition to LISTEN state.
                                         */
        BPF_SOCK_OPS_RTT_CB,            /* Called on every RTT.
+                                        * Arg1: measured RTT input (mrtt)
+                                        * Arg2: updated srtt
                                         */
        BPF_SOCK_OPS_PARSE_HDR_OPT_CB,  /* Parse the header option.
                                         * It will be called to handle