On 12/7/24 9:37 AM, Jason Xing wrote:
From: Jason Xing <kernelxing@xxxxxxxxxxx>
Passing the hwtstamp to bpf prog which can print.
Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
---
include/net/sock.h | 6 ++++--
net/core/skbuff.c | 17 +++++++++++++----
net/core/sock.c | 4 +++-
3 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index f88a00108a2f..9bc883573208 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2921,9 +2921,11 @@ int sock_set_timestamping(struct sock *sk, int optname,
void sock_enable_timestamps(struct sock *sk);
#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_SYSCALL)
-void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op);
+void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op,
+ u32 nargs, u32 *args);
#else
-static inline void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op)
+static inline void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op,
+ u32 nargs, u32 *args)
{
}
#endif
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 48b0c71e9522..182a44815630 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5539,8 +5539,12 @@ void skb_complete_tx_timestamp(struct sk_buff *skb,
}
EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
-static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, int tstype)
+static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb,
+ struct skb_shared_hwtstamps *hwtstamps,
+ int tstype)
{
+ struct timespec64 tstamp;
+ u32 args[2] = {0, 0};
int op;
if (!sk)
@@ -5552,6 +5556,11 @@ static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, int tstype
break;
case SCM_TSTAMP_SND:
op = BPF_SOCK_OPS_TS_SW_OPT_CB;
+ if (hwtstamps) {
+ tstamp = ktime_to_timespec64(hwtstamps->hwtstamp);
Avoid this conversion which is likely not useful to the bpf prog. Directly pass
hwtstamps->hwtstamp (in ns?) to the bpf prog. Put lower 32bits in args[0] and
higher 32bits in args[1].
Also, how about adding a BPF_SOCK_OPS_TS_"HW"_OPT_CB for the "hwtstamps != NULL"
case instead of reusing the BPF_SOCK_OPS_TS_"SW"_OPT_CB?
A more subtle thing for the hwtstamps case is, afaik the bpf prog will not be
called. All drivers are still only testing SKBTX_HW_TSTAMP instead of testing
(SKBTX_HW_TSTAMP | SKBTX_BPF).
There are a lot of drivers to change though. A quick thought is to rename the
existing SKBTX_HW_TSTAMP (e.g. __SKBTX_HW_TSTAMP = 1 << 0) and define
SKBTX_HW_TSTAMP like:
#define SKBTX_HW_TSTAMP (__SKBTX_HW_TSTAMP | SKBTX_BPF)
Then change some of the existing skb_shinfo(skb)->tx_flags "setting" site to use
__SKBTX_HW_TSTAMP instead. e.g. in __sock_tx_timestamp(). Not very pretty but
may be still better than changing many drivers. May be there is a better way...
While talking about where to test the SKBTX_BPF bit, I wonder if the new
skb_tstamp_is_set() is needed. For the non SKBTX_HW_TSTAMP case, the number of
tx_flags testing sites should be limited, so should be easy to add the SKBTX_BPF
bit test. e.g. at the __dev_queue_xmit, test "if
(unlikely(skb_shinfo(skb)->tx_flags & (SKBTX_SCHED_TSTAMP | SKBTX_BPF)))". Patch
6 has also tested the bpf specific bit at tcp_ack_tstamp() before calling the
__skb_tstamp_tx().
At the beginning of __skb_tstamp_tx(), do something like this:
void __skb_tstamp_tx(struct sk_buff *orig_skb,
const struct sk_buff *ack_skb,
struct skb_shared_hwtstamps *hwtstamps,
struct sock *sk, int tstype)
{
if (cgroup_bpf_enabled(CGROUP_SOCK_OPS) &&
unlikely(skb_shinfo(skb)->tx_flags & SKBTX_BPF))
__skb_tstamp_tx_bpf(sk, orig_skb, hwtstamps, tstype);
if (unlikely(!(skb_shinfo(skb)->tx_flags & ~SKBTX_BPF)))
return;
Then the new skb_tstamp_tx_output() shuffle is probably not be needed also.
+ args[0] = tstamp.tv_sec;
+ args[1] = tstamp.tv_nsec;
+ }
break;
case SCM_TSTAMP_ACK:
op = BPF_SOCK_OPS_TS_ACK_OPT_CB;
@@ -5560,7 +5569,7 @@ static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, int tstype
return;
}
- bpf_skops_tx_timestamping(sk, skb, op);
+ bpf_skops_tx_timestamping(sk, skb, op, 2, args);
}
static void skb_tstamp_tx_output(struct sk_buff *orig_skb,
@@ -5651,7 +5660,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
if (unlikely(skb_tstamp_is_set(orig_skb, tstype, false)))
skb_tstamp_tx_output(orig_skb, ack_skb, hwtstamps, sk, tstype);
if (unlikely(skb_tstamp_is_set(orig_skb, tstype, true)))
- __skb_tstamp_tx_bpf(sk, orig_skb, tstype);
+ __skb_tstamp_tx_bpf(sk, orig_skb, hwtstamps, tstype);
}
EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
@@ -5662,7 +5671,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
skb_tstamp_tx_output(orig_skb, NULL, hwtstamps, orig_skb->sk, tstype);
if (unlikely(skb_tstamp_is_set(orig_skb, tstype, true)))
- __skb_tstamp_tx_bpf(orig_skb->sk, orig_skb, tstype);
+ __skb_tstamp_tx_bpf(orig_skb->sk, orig_skb, hwtstamps, tstype);
}
EXPORT_SYMBOL_GPL(skb_tstamp_tx);
diff --git a/net/core/sock.c b/net/core/sock.c
index 79cb5c74c76c..504939bafe0c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -942,7 +942,8 @@ int sock_set_timestamping(struct sock *sk, int optname,
}
#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_SYSCALL)
-void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op)
+void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op,
+ u32 nargs, u32 *args)
Directly pass hwtstamps->hwtstamp instead of args and nargs. Save a memcpy below.
{
struct bpf_sock_ops_kern sock_ops;
@@ -952,6 +953,7 @@ void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op)
sock_ops.op = op;
sock_ops.is_fullsock = 1;
sock_ops.sk = sk;
+ memcpy(sock_ops.args, args, nargs * sizeof(*args));
__cgroup_bpf_run_filter_sock_ops(sk, &sock_ops, CGROUP_SOCK_OPS);
}
#endif
