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       1                 :            : /* SPDX-License-Identifier: GPL-2.0-only */
       2                 :            : /* include/net/xdp.h
       3                 :            :  *
       4                 :            :  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
       5                 :            :  */
       6                 :            : #ifndef __LINUX_NET_XDP_H__
       7                 :            : #define __LINUX_NET_XDP_H__
       8                 :            : 
       9                 :            : /**
      10                 :            :  * DOC: XDP RX-queue information
      11                 :            :  *
      12                 :            :  * The XDP RX-queue info (xdp_rxq_info) is associated with the driver
      13                 :            :  * level RX-ring queues.  It is information that is specific to how
      14                 :            :  * the driver have configured a given RX-ring queue.
      15                 :            :  *
      16                 :            :  * Each xdp_buff frame received in the driver carry a (pointer)
      17                 :            :  * reference to this xdp_rxq_info structure.  This provides the XDP
      18                 :            :  * data-path read-access to RX-info for both kernel and bpf-side
      19                 :            :  * (limited subset).
      20                 :            :  *
      21                 :            :  * For now, direct access is only safe while running in NAPI/softirq
      22                 :            :  * context.  Contents is read-mostly and must not be updated during
      23                 :            :  * driver NAPI/softirq poll.
      24                 :            :  *
      25                 :            :  * The driver usage API is a register and unregister API.
      26                 :            :  *
      27                 :            :  * The struct is not directly tied to the XDP prog.  A new XDP prog
      28                 :            :  * can be attached as long as it doesn't change the underlying
      29                 :            :  * RX-ring.  If the RX-ring does change significantly, the NIC driver
      30                 :            :  * naturally need to stop the RX-ring before purging and reallocating
      31                 :            :  * memory.  In that process the driver MUST call unregistor (which
      32                 :            :  * also apply for driver shutdown and unload).  The register API is
      33                 :            :  * also mandatory during RX-ring setup.
      34                 :            :  */
      35                 :            : 
      36                 :            : enum xdp_mem_type {
      37                 :            :         MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
      38                 :            :         MEM_TYPE_PAGE_ORDER0,     /* Orig XDP full page model */
      39                 :            :         MEM_TYPE_PAGE_POOL,
      40                 :            :         MEM_TYPE_ZERO_COPY,
      41                 :            :         MEM_TYPE_MAX,
      42                 :            : };
      43                 :            : 
      44                 :            : /* XDP flags for ndo_xdp_xmit */
      45                 :            : #define XDP_XMIT_FLUSH          (1U << 0) /* doorbell signal consumer */
      46                 :            : #define XDP_XMIT_FLAGS_MASK     XDP_XMIT_FLUSH
      47                 :            : 
      48                 :            : struct xdp_mem_info {
      49                 :            :         u32 type; /* enum xdp_mem_type, but known size type */
      50                 :            :         u32 id;
      51                 :            : };
      52                 :            : 
      53                 :            : struct page_pool;
      54                 :            : 
      55                 :            : struct zero_copy_allocator {
      56                 :            :         void (*free)(struct zero_copy_allocator *zca, unsigned long handle);
      57                 :            : };
      58                 :            : 
      59                 :            : struct xdp_rxq_info {
      60                 :            :         struct net_device *dev;
      61                 :            :         u32 queue_index;
      62                 :            :         u32 reg_state;
      63                 :            :         struct xdp_mem_info mem;
      64                 :            : } ____cacheline_aligned; /* perf critical, avoid false-sharing */
      65                 :            : 
      66                 :            : struct xdp_buff {
      67                 :            :         void *data;
      68                 :            :         void *data_end;
      69                 :            :         void *data_meta;
      70                 :            :         void *data_hard_start;
      71                 :            :         unsigned long handle;
      72                 :            :         struct xdp_rxq_info *rxq;
      73                 :            : };
      74                 :            : 
      75                 :            : struct xdp_frame {
      76                 :            :         void *data;
      77                 :            :         u16 len;
      78                 :            :         u16 headroom;
      79                 :            :         u16 metasize;
      80                 :            :         /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
      81                 :            :          * while mem info is valid on remote CPU.
      82                 :            :          */
      83                 :            :         struct xdp_mem_info mem;
      84                 :            :         struct net_device *dev_rx; /* used by cpumap */
      85                 :            : };
      86                 :            : 
      87                 :            : /* Clear kernel pointers in xdp_frame */
      88                 :            : static inline void xdp_scrub_frame(struct xdp_frame *frame)
      89                 :            : {
      90                 :          0 :         frame->data = NULL;
      91                 :          0 :         frame->dev_rx = NULL;
      92                 :            : }
      93                 :            : 
      94                 :            : struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
      95                 :            : 
      96                 :            : /* Convert xdp_buff to xdp_frame */
      97                 :            : static inline
      98                 :          0 : struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
      99                 :            : {
     100                 :            :         struct xdp_frame *xdp_frame;
     101                 :            :         int metasize;
     102                 :            :         int headroom;
     103                 :            : 
     104         [ #  # ]:          0 :         if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY)
     105                 :          0 :                 return xdp_convert_zc_to_xdp_frame(xdp);
     106                 :            : 
     107                 :            :         /* Assure headroom is available for storing info */
     108                 :          0 :         headroom = xdp->data - xdp->data_hard_start;
     109                 :          0 :         metasize = xdp->data - xdp->data_meta;
     110                 :          0 :         metasize = metasize > 0 ? metasize : 0;
     111         [ #  # ]:          0 :         if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
     112                 :            :                 return NULL;
     113                 :            : 
     114                 :            :         /* Store info in top of packet */
     115                 :            :         xdp_frame = xdp->data_hard_start;
     116                 :            : 
     117                 :          0 :         xdp_frame->data = xdp->data;
     118                 :          0 :         xdp_frame->len  = xdp->data_end - xdp->data;
     119                 :          0 :         xdp_frame->headroom = headroom - sizeof(*xdp_frame);
     120                 :          0 :         xdp_frame->metasize = metasize;
     121                 :            : 
     122                 :            :         /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
     123                 :          0 :         xdp_frame->mem = xdp->rxq->mem;
     124                 :            : 
     125                 :          0 :         return xdp_frame;
     126                 :            : }
     127                 :            : 
     128                 :            : void xdp_return_frame(struct xdp_frame *xdpf);
     129                 :            : void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
     130                 :            : void xdp_return_buff(struct xdp_buff *xdp);
     131                 :            : 
     132                 :            : /* When sending xdp_frame into the network stack, then there is no
     133                 :            :  * return point callback, which is needed to release e.g. DMA-mapping
     134                 :            :  * resources with page_pool.  Thus, have explicit function to release
     135                 :            :  * frame resources.
     136                 :            :  */
     137                 :            : void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
     138                 :            : static inline void xdp_release_frame(struct xdp_frame *xdpf)
     139                 :            : {
     140                 :          0 :         struct xdp_mem_info *mem = &xdpf->mem;
     141                 :            : 
     142                 :            :         /* Curr only page_pool needs this */
     143         [ #  # ]:          0 :         if (mem->type == MEM_TYPE_PAGE_POOL)
     144                 :          0 :                 __xdp_release_frame(xdpf->data, mem);
     145                 :            : }
     146                 :            : 
     147                 :            : int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
     148                 :            :                      struct net_device *dev, u32 queue_index);
     149                 :            : void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
     150                 :            : void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
     151                 :            : bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
     152                 :            : int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
     153                 :            :                                enum xdp_mem_type type, void *allocator);
     154                 :            : void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
     155                 :            : 
     156                 :            : /* Drivers not supporting XDP metadata can use this helper, which
     157                 :            :  * rejects any room expansion for metadata as a result.
     158                 :            :  */
     159                 :            : static __always_inline void
     160                 :            : xdp_set_data_meta_invalid(struct xdp_buff *xdp)
     161                 :            : {
     162                 :            :         xdp->data_meta = xdp->data + 1;
     163                 :            : }
     164                 :            : 
     165                 :            : static __always_inline bool
     166                 :            : xdp_data_meta_unsupported(const struct xdp_buff *xdp)
     167                 :            : {
     168                 :          0 :         return unlikely(xdp->data_meta > xdp->data);
     169                 :            : }
     170                 :            : 
     171                 :            : struct xdp_attachment_info {
     172                 :            :         struct bpf_prog *prog;
     173                 :            :         u32 flags;
     174                 :            : };
     175                 :            : 
     176                 :            : struct netdev_bpf;
     177                 :            : int xdp_attachment_query(struct xdp_attachment_info *info,
     178                 :            :                          struct netdev_bpf *bpf);
     179                 :            : bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
     180                 :            :                              struct netdev_bpf *bpf);
     181                 :            : void xdp_attachment_setup(struct xdp_attachment_info *info,
     182                 :            :                           struct netdev_bpf *bpf);
     183                 :            : 
     184                 :            : #endif /* __LINUX_NET_XDP_H__ */