296 lines
8.5 KiB
C
296 lines
8.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/* include/net/xdp.h
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*
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* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
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*/
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#ifndef __LINUX_NET_XDP_H__
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#define __LINUX_NET_XDP_H__
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#include <linux/skbuff.h> /* skb_shared_info */
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/**
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* DOC: XDP RX-queue information
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*
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* The XDP RX-queue info (xdp_rxq_info) is associated with the driver
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* level RX-ring queues. It is information that is specific to how
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* the driver have configured a given RX-ring queue.
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*
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* Each xdp_buff frame received in the driver carry a (pointer)
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* reference to this xdp_rxq_info structure. This provides the XDP
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* data-path read-access to RX-info for both kernel and bpf-side
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* (limited subset).
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*
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* For now, direct access is only safe while running in NAPI/softirq
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* context. Contents is read-mostly and must not be updated during
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* driver NAPI/softirq poll.
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*
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* The driver usage API is a register and unregister API.
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*
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* The struct is not directly tied to the XDP prog. A new XDP prog
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* can be attached as long as it doesn't change the underlying
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* RX-ring. If the RX-ring does change significantly, the NIC driver
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* naturally need to stop the RX-ring before purging and reallocating
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* memory. In that process the driver MUST call unregistor (which
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* also apply for driver shutdown and unload). The register API is
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* also mandatory during RX-ring setup.
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*/
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enum xdp_mem_type {
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MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
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MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
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MEM_TYPE_PAGE_POOL,
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MEM_TYPE_XSK_BUFF_POOL,
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MEM_TYPE_MAX,
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};
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/* XDP flags for ndo_xdp_xmit */
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#define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */
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#define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH
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struct xdp_mem_info {
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u32 type; /* enum xdp_mem_type, but known size type */
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u32 id;
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};
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struct page_pool;
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struct xdp_rxq_info {
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struct net_device *dev;
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u32 queue_index;
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u32 reg_state;
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struct xdp_mem_info mem;
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unsigned int napi_id;
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} ____cacheline_aligned; /* perf critical, avoid false-sharing */
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struct xdp_txq_info {
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struct net_device *dev;
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};
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struct xdp_buff {
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void *data;
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void *data_end;
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void *data_meta;
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void *data_hard_start;
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struct xdp_rxq_info *rxq;
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struct xdp_txq_info *txq;
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u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
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};
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static __always_inline void
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xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
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{
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xdp->frame_sz = frame_sz;
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xdp->rxq = rxq;
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}
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static __always_inline void
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xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
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int headroom, int data_len, const bool meta_valid)
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{
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unsigned char *data = hard_start + headroom;
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xdp->data_hard_start = hard_start;
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xdp->data = data;
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xdp->data_end = data + data_len;
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xdp->data_meta = meta_valid ? data : data + 1;
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}
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/* Reserve memory area at end-of data area.
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*
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* This macro reserves tailroom in the XDP buffer by limiting the
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* XDP/BPF data access to data_hard_end. Notice same area (and size)
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* is used for XDP_PASS, when constructing the SKB via build_skb().
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*/
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#define xdp_data_hard_end(xdp) \
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((xdp)->data_hard_start + (xdp)->frame_sz - \
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SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
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static inline struct skb_shared_info *
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xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
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{
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return (struct skb_shared_info *)xdp_data_hard_end(xdp);
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}
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struct xdp_frame {
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void *data;
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u16 len;
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u16 headroom;
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u32 metasize:8;
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u32 frame_sz:24;
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/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
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* while mem info is valid on remote CPU.
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*/
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struct xdp_mem_info mem;
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struct net_device *dev_rx; /* used by cpumap */
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};
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#define XDP_BULK_QUEUE_SIZE 16
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struct xdp_frame_bulk {
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int count;
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void *xa;
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void *q[XDP_BULK_QUEUE_SIZE];
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};
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static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
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{
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/* bq->count will be zero'ed when bq->xa gets updated */
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bq->xa = NULL;
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}
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static inline struct skb_shared_info *
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xdp_get_shared_info_from_frame(struct xdp_frame *frame)
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{
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void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
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return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
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SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
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}
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struct xdp_cpumap_stats {
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unsigned int redirect;
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unsigned int pass;
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unsigned int drop;
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};
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/* Clear kernel pointers in xdp_frame */
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static inline void xdp_scrub_frame(struct xdp_frame *frame)
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{
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frame->data = NULL;
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frame->dev_rx = NULL;
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}
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/* Avoids inlining WARN macro in fast-path */
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void xdp_warn(const char *msg, const char *func, const int line);
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#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
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struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
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struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
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struct sk_buff *skb,
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struct net_device *dev);
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struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
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struct net_device *dev);
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int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp);
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struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf);
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static inline
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void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
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{
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xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
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xdp->data = frame->data;
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xdp->data_end = frame->data + frame->len;
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xdp->data_meta = frame->data - frame->metasize;
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xdp->frame_sz = frame->frame_sz;
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}
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static inline
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int xdp_update_frame_from_buff(struct xdp_buff *xdp,
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struct xdp_frame *xdp_frame)
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{
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int metasize, headroom;
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/* Assure headroom is available for storing info */
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headroom = xdp->data - xdp->data_hard_start;
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metasize = xdp->data - xdp->data_meta;
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metasize = metasize > 0 ? metasize : 0;
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if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
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return -ENOSPC;
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/* Catch if driver didn't reserve tailroom for skb_shared_info */
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if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
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XDP_WARN("Driver BUG: missing reserved tailroom");
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return -ENOSPC;
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}
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xdp_frame->data = xdp->data;
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xdp_frame->len = xdp->data_end - xdp->data;
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xdp_frame->headroom = headroom - sizeof(*xdp_frame);
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xdp_frame->metasize = metasize;
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xdp_frame->frame_sz = xdp->frame_sz;
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return 0;
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}
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/* Convert xdp_buff to xdp_frame */
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static inline
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struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
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{
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struct xdp_frame *xdp_frame;
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if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
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return xdp_convert_zc_to_xdp_frame(xdp);
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/* Store info in top of packet */
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xdp_frame = xdp->data_hard_start;
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if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
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return NULL;
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/* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
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xdp_frame->mem = xdp->rxq->mem;
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return xdp_frame;
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}
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void xdp_return_frame(struct xdp_frame *xdpf);
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void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
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void xdp_return_buff(struct xdp_buff *xdp);
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void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
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void xdp_return_frame_bulk(struct xdp_frame *xdpf,
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struct xdp_frame_bulk *bq);
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/* When sending xdp_frame into the network stack, then there is no
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* return point callback, which is needed to release e.g. DMA-mapping
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* resources with page_pool. Thus, have explicit function to release
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* frame resources.
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*/
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void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
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static inline void xdp_release_frame(struct xdp_frame *xdpf)
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{
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struct xdp_mem_info *mem = &xdpf->mem;
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/* Curr only page_pool needs this */
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if (mem->type == MEM_TYPE_PAGE_POOL)
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__xdp_release_frame(xdpf->data, mem);
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}
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int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
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struct net_device *dev, u32 queue_index, unsigned int napi_id);
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void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
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void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
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bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
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int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
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enum xdp_mem_type type, void *allocator);
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void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
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/* Drivers not supporting XDP metadata can use this helper, which
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* rejects any room expansion for metadata as a result.
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*/
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static __always_inline void
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xdp_set_data_meta_invalid(struct xdp_buff *xdp)
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{
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xdp->data_meta = xdp->data + 1;
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}
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static __always_inline bool
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xdp_data_meta_unsupported(const struct xdp_buff *xdp)
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{
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return unlikely(xdp->data_meta > xdp->data);
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}
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static inline bool xdp_metalen_invalid(unsigned long metalen)
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{
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return (metalen & (sizeof(__u32) - 1)) || (metalen > 32);
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}
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struct xdp_attachment_info {
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struct bpf_prog *prog;
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u32 flags;
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};
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struct netdev_bpf;
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void xdp_attachment_setup(struct xdp_attachment_info *info,
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struct netdev_bpf *bpf);
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#define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE
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#endif /* __LINUX_NET_XDP_H__ */
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