From 2deaf7f42b8c551e84da20483ca2d4a65c3623b3 Mon Sep 17 00:00:00 2001 From: Jason Xing Date: Thu, 20 Feb 2025 15:29:36 +0800 Subject: [PATCH] bpf: Add BPF_SOCK_OPS_TSTAMP_SND_HW_CB callback Support hw SCM_TSTAMP_SND case for bpf timestamping. Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_SND_HW_CB. This callback will occur at the same timestamping point as the user space's hardware SCM_TSTAMP_SND. The BPF program can use it to get the same SCM_TSTAMP_SND timestamp without modifying the user-space application. To avoid increasing the code complexity, replace SKBTX_HW_TSTAMP with SKBTX_HW_TSTAMP_NOBPF instead of changing numerous callers from driver side using SKBTX_HW_TSTAMP. The new definition of SKBTX_HW_TSTAMP means the combination tests of socket timestamping and bpf timestamping. After this patch, drivers can work under the bpf timestamping. Considering some drivers don't assign the skb with hardware timestamp, this patch does the assignment and then BPF program can acquire the hwstamp from skb directly. Signed-off-by: Jason Xing Signed-off-by: Martin KaFai Lau Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250220072940.99994-9-kerneljasonxing@gmail.com --- include/linux/skbuff.h | 4 +++- include/uapi/linux/bpf.h | 4 ++++ net/core/skbuff.c | 11 +++++++---- net/dsa/user.c | 2 +- net/socket.c | 2 +- tools/include/uapi/linux/bpf.h | 4 ++++ 6 files changed, 20 insertions(+), 7 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 76582500c5ea..0b4f1889500d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -470,7 +470,7 @@ struct skb_shared_hwtstamps { /* Definitions for tx_flags in struct skb_shared_info */ enum { /* generate hardware time stamp */ - SKBTX_HW_TSTAMP = 1 << 0, + SKBTX_HW_TSTAMP_NOBPF = 1 << 0, /* generate software time stamp when queueing packet to NIC */ SKBTX_SW_TSTAMP = 1 << 1, @@ -494,6 +494,8 @@ enum { SKBTX_BPF = 1 << 7, }; +#define SKBTX_HW_TSTAMP (SKBTX_HW_TSTAMP_NOBPF | SKBTX_BPF) + #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \ SKBTX_SCHED_TSTAMP | \ SKBTX_BPF) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index abe8d6c30dae..72045c242396 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -7040,6 +7040,10 @@ enum { * to the nic when SK_BPF_CB_TX_TIMESTAMPING * feature is on. */ + BPF_SOCK_OPS_TSTAMP_SND_HW_CB, /* Called in hardware phase when + * SK_BPF_CB_TX_TIMESTAMPING feature + * is on. + */ }; /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 308db7dae1ab..77b8866f94c5 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5547,7 +5547,7 @@ static bool skb_tstamp_tx_report_so_timestamping(struct sk_buff *skb, case SCM_TSTAMP_SCHED: return skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP; case SCM_TSTAMP_SND: - return skb_shinfo(skb)->tx_flags & (hwtstamps ? SKBTX_HW_TSTAMP : + return skb_shinfo(skb)->tx_flags & (hwtstamps ? SKBTX_HW_TSTAMP_NOBPF : SKBTX_SW_TSTAMP); case SCM_TSTAMP_ACK: return TCP_SKB_CB(skb)->txstamp_ack; @@ -5568,9 +5568,12 @@ static void skb_tstamp_tx_report_bpf_timestamping(struct sk_buff *skb, op = BPF_SOCK_OPS_TSTAMP_SCHED_CB; break; case SCM_TSTAMP_SND: - if (hwtstamps) - return; - op = BPF_SOCK_OPS_TSTAMP_SND_SW_CB; + if (hwtstamps) { + op = BPF_SOCK_OPS_TSTAMP_SND_HW_CB; + *skb_hwtstamps(skb) = *hwtstamps; + } else { + op = BPF_SOCK_OPS_TSTAMP_SND_SW_CB; + } break; default: return; diff --git a/net/dsa/user.c b/net/dsa/user.c index 2296a4ead020..804dc7dac4f2 100644 --- a/net/dsa/user.c +++ b/net/dsa/user.c @@ -897,7 +897,7 @@ static void dsa_skb_tx_timestamp(struct dsa_user_priv *p, { struct dsa_switch *ds = p->dp->ds; - if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) + if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP_NOBPF)) return; if (!ds->ops->port_txtstamp) diff --git a/net/socket.c b/net/socket.c index 28bae5a94234..0545e9ea7058 100644 --- a/net/socket.c +++ b/net/socket.c @@ -681,7 +681,7 @@ void __sock_tx_timestamp(__u32 tsflags, __u8 *tx_flags) u8 flags = *tx_flags; if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) { - flags |= SKBTX_HW_TSTAMP; + flags |= SKBTX_HW_TSTAMP_NOBPF; /* PTP hardware clocks can provide a free running cycle counter * as a time base for virtual clocks. Tell driver to use the diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index abe8d6c30dae..72045c242396 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -7040,6 +7040,10 @@ enum { * to the nic when SK_BPF_CB_TX_TIMESTAMPING * feature is on. */ + BPF_SOCK_OPS_TSTAMP_SND_HW_CB, /* Called in hardware phase when + * SK_BPF_CB_TX_TIMESTAMPING feature + * is on. + */ }; /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect