Add TCP_SKB_CB(skb)->sacked as the 4th arg of sockops passed to bpf
program. Then we can get the retransmission efficiency by counting skbs
w/ and w/o TCPCB_EVER_RETRANS mark. And for this purpose, sacked
updating is moved after the BPF_SOCK_OPS_RETRANS_CB hook.
Signed-off-by: Philo Lu <lulie@xxxxxxxxxxxxxxxxx>
---
include/net/tcp.h | 14 ++++++++++++++
include/uapi/linux/bpf.h | 2 ++
net/ipv4/tcp_output.c | 9 +++++----
tools/include/uapi/linux/bpf.h | 2 ++
4 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6ae35199d3b3..7defe67183c9 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2660,6 +2660,14 @@ static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
return tcp_call_bpf(sk, op, 3, args);
}
+static inline int tcp_call_bpf_4arg(struct sock *sk, int op, u32 arg1, u32 arg2,
+ u32 arg3, u32 arg4)
+{
+ u32 args[4] = {arg1, arg2, arg3, arg4};
+
+ return tcp_call_bpf(sk, op, 4, args);
+}
+
#else
static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
{
@@ -2677,6 +2685,12 @@ static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
return -EPERM;
}
+static inline int tcp_call_bpf_4arg(struct sock *sk, int op, u32 arg1, u32 arg2,
+ u32 arg3, u32 arg4)
+{
+ return -EPERM;
+}
+
#endif
static inline u32 tcp_timeout_init(struct sock *sk)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index cee0a7915c08..df6bb9a62e0b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6938,6 +6938,8 @@ enum {
* Arg2: # segments
* Arg3: return value of
* tcp_transmit_skb (0 => success)
+ * Arg4: TCP_SKB_CB(skb)->sacked before
+ * TCPCB_EVER_RETRANS marking
*/
BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
* Arg1: old_state
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e3167ad96567..370e6cee6794 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3387,15 +3387,16 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
}
+ if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG))
+ tcp_call_bpf_4arg(sk, BPF_SOCK_OPS_RETRANS_CB,
+ TCP_SKB_CB(skb)->seq, segs, err,
+ TCP_SKB_CB(skb)->sacked);
+
/* To avoid taking spuriously low RTT samples based on a timestamp
* for a transmit that never happened, always mark EVER_RETRANS
*/
TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS;
- if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG))
- tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RETRANS_CB,
- TCP_SKB_CB(skb)->seq, segs, err);
-
if (likely(!err)) {
trace_tcp_retransmit_skb(sk, skb);
} else if (err != -EBUSY) {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index cee0a7915c08..df6bb9a62e0b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6938,6 +6938,8 @@ enum {
* Arg2: # segments
* Arg3: return value of
* tcp_transmit_skb (0 => success)
+ * Arg4: TCP_SKB_CB(skb)->sacked before
+ * TCPCB_EVER_RETRANS marking
*/
BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
* Arg1: old_state
--
2.32.0.3.g01195cf9f
