[[RFC xdp-hints] 13/16] libbpf: Helpers to access XDP frame metadata
From: Ederson de Souza <hidden>
Date: 2021-08-03 01:03:54
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
Two new pairs of helpers: `xsk_umem__adjust_prod_data` and `xsk_umem__adjust_prod_data_meta` for data that is being produced by the application - such as data that will be sent; and `xsk_umem__adjust_cons_data` and `xsk_umem__adjust_cons_data_meta`, for data being consumed - such as data obtained from the completion queue. Those function should usually be used on data obtained via `xsk_umem__get_data`. Didn't change this function to avoid API breaks. Signed-off-by: Ederson de Souza <redacted> --- tools/lib/bpf/libbpf.map | 4 ++++ tools/lib/bpf/xsk.c | 26 ++++++++++++++++++++++++++ tools/lib/bpf/xsk.h | 7 +++++++ 3 files changed, 37 insertions(+)
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 492db50a4cd7..663585f7f186 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map@@ -375,4 +375,8 @@ LIBBPF_0.5.0 { bpf_map_lookup_and_delete_elem_flags; bpf_object__gen_loader; libbpf_set_strict_mode; + xsk_umem__adjust_cons_data; + xsk_umem__adjust_cons_data_meta; + xsk_umem__adjust_prod_data; + xsk_umem__adjust_prod_data_meta; } LIBBPF_0.4.0;
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index e9b619aa0cdf..17e8045eac0e 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c@@ -119,6 +119,30 @@ int xsk_socket__fd(const struct xsk_socket *xsk) return xsk ? xsk->fd : -EINVAL; } +void *xsk_umem__adjust_prod_data(void *umem_data, const struct xsk_umem *umem) +{ + return umem_data + umem->config.frame_headroom + umem->config.xdp_headroom; +} + +void *xsk_umem__adjust_prod_data_meta(void *umem_data, const struct xsk_umem *umem) +{ + if (!umem->config.xdp_headroom) + return NULL; + return umem_data; +} + +void *xsk_umem__adjust_cons_data(void *umem_data, const struct xsk_umem *umem) +{ + return umem_data; +} + +void *xsk_umem__adjust_cons_data_meta(void *umem_data, const struct xsk_umem *umem) +{ + if (!umem->config.xdp_headroom) + return NULL; + return umem_data; +} + static bool xsk_page_aligned(void *buffer) { unsigned long addr = (unsigned long)buffer;
@@ -135,6 +159,7 @@ static void xsk_set_umem_config(struct xsk_umem_config *cfg, cfg->frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE; cfg->frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM; cfg->flags = XSK_UMEM__DEFAULT_FLAGS; + cfg->xdp_headroom = XSK_UMEM__DEFAULT_XDP_HEADROOM; return; }
@@ -143,6 +168,7 @@ static void xsk_set_umem_config(struct xsk_umem_config *cfg, cfg->frame_size = usr_cfg->frame_size; cfg->frame_headroom = usr_cfg->frame_headroom; cfg->flags = usr_cfg->flags; + cfg->xdp_headroom = usr_cfg->xdp_headroom; } static int xsk_set_xdp_socket_config(struct xsk_socket_config *cfg,
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
index 01c12dca9c10..7f4143150746 100644
--- a/tools/lib/bpf/xsk.h
+++ b/tools/lib/bpf/xsk.h@@ -248,12 +248,18 @@ 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); +LIBBPF_API void *xsk_umem__adjust_prod_data(void *umem_data, const struct xsk_umem *umem); +LIBBPF_API void *xsk_umem__adjust_prod_data_meta(void *umem_data, const struct xsk_umem *umem); +LIBBPF_API void *xsk_umem__adjust_cons_data(void *umem_data, const struct xsk_umem *umem); +LIBBPF_API void *xsk_umem__adjust_cons_data_meta(void *umem_data, const struct xsk_umem *umem); + #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 */ #define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT) #define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0 #define XSK_UMEM__DEFAULT_FLAGS 0 +#define XSK_UMEM__DEFAULT_XDP_HEADROOM 0 struct xsk_umem_config { __u32 fill_size;
@@ -261,6 +267,7 @@ struct xsk_umem_config { __u32 frame_size; __u32 frame_headroom; __u32 flags; + __u32 xdp_headroom; }; LIBBPF_API int xsk_setup_xdp_prog(int ifindex,
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2.32.0