[RFC bpf-next 2/5] libbpf: SO_TXTIME support in AF_XDP
From: Kishen Maloor <hidden>
Date: 2021-08-03 17:10:31
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
This change adds userspace support for SO_TXTIME in AF_XDP
to include a specific TXTIME (aka "Launch Time")
with XDP frames issued from userspace XDP applications.
The userspace API has been expanded with two helper functons:
- int xsk_socket__enable_so_txtime(struct xsk_socket *xsk, bool enable)
Sets the SO_TXTIME option on the AF_XDP socket (using setsockopt()).
- void xsk_umem__set_md_txtime(void *umem_area, __u64 chunkAddr,
__s64 txtime)
Packages the application supplied TXTIME into struct xdp_user_tx_metadata:
struct xdp_user_tx_metadata {
__u64 timestamp;
__u32 md_valid;
__u32 btf_id;
};
and stores it in the XDP metadata area, which precedes the XDP frame.
Signed-off-by: Kishen Maloor <redacted>
---
tools/include/uapi/linux/if_xdp.h | 2 ++
tools/include/uapi/linux/xdp_md_std.h | 14 ++++++++++++++
tools/lib/bpf/xsk.h | 27 ++++++++++++++++++++++++++-
3 files changed, 42 insertions(+), 1 deletion(-)
create mode 100644 tools/include/uapi/linux/xdp_md_std.h
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index a78a8096f4ce..31f81f82ed86 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h@@ -106,6 +106,8 @@ struct xdp_desc { __u32 options; }; +#define XDP_DESC_OPTION_METADATA (1 << 0) + /* UMEM descriptor is __u64 */ #endif /* _LINUX_IF_XDP_H */
diff --git a/tools/include/uapi/linux/xdp_md_std.h b/tools/include/uapi/linux/xdp_md_std.h
new file mode 100644
index 000000000000..f00996a61639
--- /dev/null
+++ b/tools/include/uapi/linux/xdp_md_std.h@@ -0,0 +1,14 @@ +#ifndef _UAPI_LINUX_XDP_MD_STD_H +#define _UAPI_LINUX_XDP_MD_STD_H + +#include <linux/types.h> + +#define XDP_METADATA_USER_TX_TIMESTAMP 0x1 + +struct xdp_user_tx_metadata { + __u64 timestamp; + __u32 md_valid; + __u32 btf_id; +}; + +#endif /* _UAPI_LINUX_XDP_MD_STD_H */
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
index 01c12dca9c10..1b52ffe1c9a3 100644
--- a/tools/lib/bpf/xsk.h
+++ b/tools/lib/bpf/xsk.h@@ -16,7 +16,8 @@ #include <stdint.h> #include <stdbool.h> #include <linux/if_xdp.h> - +#include <linux/xdp_md_std.h> +#include <errno.h> #include "libbpf.h" #ifdef __cplusplus
@@ -248,6 +249,30 @@ static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr) LIBBPF_API int xsk_umem__fd(const struct xsk_umem *umem); LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk); +/* Helpers for SO_TXTIME */ + +static inline void xsk_umem__set_md_txtime(void *umem_area, __u64 addr, __s64 txtime) +{ + struct xdp_user_tx_metadata *md; + + md = (struct xdp_user_tx_metadata *)&((char *)umem_area)[addr]; + + md->timestamp = txtime; + md->md_valid |= XDP_METADATA_USER_TX_TIMESTAMP; +} + +static inline int xsk_socket__enable_so_txtime(struct xsk_socket *xsk, bool enable) +{ + unsigned int val = (enable) ? 1 : 0; + int err; + + err = setsockopt(xsk_socket__fd(xsk), SOL_XDP, SO_TXTIME, &val, sizeof(val)); + + if (err) + return -errno; + return 0; +} + #define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048 #define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048 #define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */
--
2.24.3 (Apple Git-128)