/* SPDX-License-Identifier: GPL-2.0-only */ /* Copyright (C) 2024-2025 Intel Corporation */ #ifndef __LIBETH_RX_H #define __LIBETH_RX_H #include <linux/if_vlan.h> #include <net/page_pool/helpers.h> #include <net/xdp.h> /* Rx buffer management */ /* Space reserved in front of each frame */ #define LIBETH_SKB_HEADROOM (NET_SKB_PAD + NET_IP_ALIGN) #define LIBETH_XDP_HEADROOM (ALIGN(XDP_PACKET_HEADROOM, NET_SKB_PAD) + \ NET_IP_ALIGN) /* Maximum headroom for worst-case calculations */ #define LIBETH_MAX_HEADROOM LIBETH_XDP_HEADROOM /* Link layer / L2 overhead: Ethernet, 2 VLAN tags (C + S), FCS */ #define LIBETH_RX_LL_LEN (ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN) /* Maximum supported L2-L4 header length */ #define LIBETH_MAX_HEAD roundup_pow_of_two(max(MAX_HEADER, 256)) /* Always use order-0 pages */ #define LIBETH_RX_PAGE_ORDER 0 /* Pick a sane buffer stride and align to a cacheline boundary */ #define LIBETH_RX_BUF_STRIDE SKB_DATA_ALIGN(128) /* HW-writeable space in one buffer: truesize - headroom/tailroom, aligned */ #define LIBETH_RX_PAGE_LEN(hr) \ ALIGN_DOWN(SKB_MAX_ORDER(hr, LIBETH_RX_PAGE_ORDER), \ LIBETH_RX_BUF_STRIDE) /** * struct libeth_fqe - structure representing an Rx buffer (fill queue element) * @netmem: network memory reference holding the buffer * @offset: offset from the page start (to the headroom) * @truesize: total space occupied by the buffer (w/ headroom and tailroom) * * Depending on the MTU, API switches between one-page-per-frame and shared * page model (to conserve memory on bigger-page platforms). In case of the * former, @offset is always 0 and @truesize is always ```PAGE_SIZE```. */ struct libeth_fqe { netmem_ref netmem; u32 offset; u32 truesize; } __aligned_largest; /** * enum libeth_fqe_type - enum representing types of Rx buffers * @LIBETH_FQE_MTU: buffer size is determined by MTU * @LIBETH_FQE_SHORT: buffer size is smaller than MTU, for short frames * @LIBETH_FQE_HDR: buffer size is ```LIBETH_MAX_HEAD```-sized, for headers */ enum libeth_fqe_type { LIBETH_FQE_MTU = 0U, LIBETH_FQE_SHORT, LIBETH_FQE_HDR, }; /** * struct libeth_fq - structure representing a buffer (fill) queue * @fp: hotpath part of the structure * @pp: &page_pool for buffer management * @fqes: array of Rx buffers * @truesize: size to allocate per buffer, w/overhead * @count: number of descriptors/buffers the queue has * @type: type of the buffers this queue has * @hsplit: flag whether header split is enabled * @xdp: flag indicating whether XDP is enabled * @buf_len: HW-writeable length per each buffer * @nid: ID of the closest NUMA node with memory */ struct libeth_fq { struct_group_tagged(libeth_fq_fp, fp, struct page_pool *pp; struct libeth_fqe *fqes; u32 truesize; u32 count; ); /* Cold fields */ enum libeth_fqe_type type:2; bool hsplit:1; bool xdp:1; u32 buf_len; int nid; }; int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi); void libeth_rx_fq_destroy(struct libeth_fq *fq); /** * libeth_rx_alloc - allocate a new Rx buffer * @fq: fill queue to allocate for * @i: index of the buffer within the queue * * Return: DMA address to be passed to HW for Rx on successful allocation, * ```DMA_MAPPING_ERROR``` otherwise. */ static inline dma_addr_t libeth_rx_alloc(const struct libeth_fq_fp *fq, u32 i) { struct libeth_fqe *buf = &fq->fqes[i]; buf->truesize = fq->truesize; buf->netmem = page_pool_dev_alloc_netmem(fq->pp, &buf->offset, &buf->truesize); if (unlikely(!buf->netmem)) return DMA_MAPPING_ERROR; return page_pool_get_dma_addr_netmem(buf->netmem) + buf->offset + fq->pp->p.offset; } void libeth_rx_recycle_slow(netmem_ref netmem); /** * libeth_rx_sync_for_cpu - synchronize or recycle buffer post DMA * @fqe: buffer to process * @len: frame length from the descriptor * * Process the buffer after it's written by HW. The regular path is to * synchronize DMA for CPU, but in case of no data it will be immediately * recycled back to its PP. * * Return: true when there's data to process, false otherwise. */ static inline bool libeth_rx_sync_for_cpu(const struct libeth_fqe *fqe, u32 len) { netmem_ref netmem = fqe->netmem; /* Very rare, but possible case. The most common reason: * the last fragment contained FCS only, which was then * stripped by the HW. */ if (unlikely(!len)) { libeth_rx_recycle_slow(netmem); return false; } page_pool_dma_sync_netmem_for_cpu(netmem_get_pp(netmem), netmem, fqe->offset, len); return true; } /* Converting abstract packet type numbers into a software structure with * the packet parameters to do O(1) lookup on Rx. */ enum { LIBETH_RX_PT_OUTER_L2 = 0U, LIBETH_RX_PT_OUTER_IPV4, LIBETH_RX_PT_OUTER_IPV6, }; enum { LIBETH_RX_PT_NOT_FRAG = 0U, LIBETH_RX_PT_FRAG, }; enum { LIBETH_RX_PT_TUNNEL_IP_NONE = 0U, LIBETH_RX_PT_TUNNEL_IP_IP, LIBETH_RX_PT_TUNNEL_IP_GRENAT, LIBETH_RX_PT_TUNNEL_IP_GRENAT_MAC, LIBETH_RX_PT_TUNNEL_IP_GRENAT_MAC_VLAN, }; enum { LIBETH_RX_PT_TUNNEL_END_NONE = 0U, LIBETH_RX_PT_TUNNEL_END_IPV4, LIBETH_RX_PT_TUNNEL_END_IPV6, }; enum { LIBETH_RX_PT_INNER_NONE = 0U, LIBETH_RX_PT_INNER_UDP, LIBETH_RX_PT_INNER_TCP, LIBETH_RX_PT_INNER_SCTP, LIBETH_RX_PT_INNER_ICMP, LIBETH_RX_PT_INNER_TIMESYNC, }; #define LIBETH_RX_PT_PAYLOAD_NONE PKT_HASH_TYPE_NONE #define LIBETH_RX_PT_PAYLOAD_L2 PKT_HASH_TYPE_L2 #define LIBETH_RX_PT_PAYLOAD_L3 PKT_HASH_TYPE_L3 #define LIBETH_RX_PT_PAYLOAD_L4 PKT_HASH_TYPE_L4 struct libeth_rx_pt { u32 outer_ip:2; u32 outer_frag:1; u32 tunnel_type:3; u32 tunnel_end_prot:2; u32 tunnel_end_frag:1; u32 inner_prot:3; enum pkt_hash_types payload_layer:2; u32 pad:2; enum xdp_rss_hash_type hash_type:16; }; /** * struct libeth_rx_csum - checksum offload bits decoded from the Rx descriptor * @l3l4p: detectable L3 and L4 integrity check is processed by the hardware * @ipe: IP checksum error * @eipe: external (outermost) IP header (only for tunels) * @eudpe: external (outermost) UDP checksum error (only for tunels) * @ipv6exadd: IPv6 header with extension headers * @l4e: L4 integrity error * @pprs: set for packets that skip checksum calculation in the HW pre parser * @nat: the packet is a UDP tunneled packet * @raw_csum_valid: set if raw checksum is valid * @pad: padding to naturally align raw_csum field * @raw_csum: raw checksum */ struct libeth_rx_csum { u32 l3l4p:1; u32 ipe:1; u32 eipe:1; u32 eudpe:1; u32 ipv6exadd:1; u32 l4e:1; u32 pprs:1; u32 nat:1; u32 raw_csum_valid:1; u32 pad:7; u32 raw_csum:16; }; /** * struct libeth_rqe_info - receive queue element info * @len: packet length * @ptype: packet type based on types programmed into the device * @eop: whether it's the last fragment of the packet * @rxe: MAC errors: CRC, Alignment, Oversize, Undersizes, Length error * @vlan: C-VLAN or S-VLAN tag depending on the VLAN offload configuration */ struct libeth_rqe_info { u32 len; u32 ptype:14; u32 eop:1; u32 rxe:1; u32 vlan:16; }; void libeth_rx_pt_gen_hash_type(struct libeth_rx_pt *pt); /** * libeth_rx_pt_get_ip_ver - get IP version from a packet type structure * @pt: packet type params * * Wrapper to compile out the IPv6 code from the drivers when not supported * by the kernel. * * Return: @pt.outer_ip or stub for IPv6 when not compiled-in. */ static inline u32 libeth_rx_pt_get_ip_ver(struct libeth_rx_pt pt) { #if !IS_ENABLED(CONFIG_IPV6) switch (pt.outer_ip) { case LIBETH_RX_PT_OUTER_IPV4: return LIBETH_RX_PT_OUTER_IPV4; default: return LIBETH_RX_PT_OUTER_L2; } #else return pt.outer_ip; #endif } /* libeth_has_*() can be used to quickly check whether the HW metadata is * available to avoid further expensive processing such as descriptor reads. * They already check for the corresponding netdev feature to be enabled, * thus can be used as drop-in replacements. */ static inline bool libeth_rx_pt_has_checksum(const struct net_device *dev, struct libeth_rx_pt pt) { /* Non-zero _INNER* is only possible when _OUTER_IPV* is set, * it is enough to check only for the L4 type. */ return likely(pt.inner_prot > LIBETH_RX_PT_INNER_NONE && (dev->features & NETIF_F_RXCSUM)); } static inline bool libeth_rx_pt_has_hash(const struct net_device *dev, struct libeth_rx_pt pt) { return likely(pt.payload_layer > LIBETH_RX_PT_PAYLOAD_NONE && (dev->features & NETIF_F_RXHASH)); } /** * libeth_rx_pt_set_hash - fill in skb hash value basing on the PT * @skb: skb to fill the hash in * @hash: 32-bit hash value from the descriptor * @pt: packet type */ static inline void libeth_rx_pt_set_hash(struct sk_buff *skb, u32 hash, struct libeth_rx_pt pt) { skb_set_hash(skb, hash, pt.payload_layer); } #endif /* __LIBETH_RX_H */
