--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+
+======
+AF_XDP
+======
+
+Overview
+========
+
+AF_XDP is an address family that is optimized for high performance
+packet processing.
+
+This document assumes that the reader is familiar with BPF and XDP. If
+not, the Cilium project has an excellent reference guide at
+http://cilium.readthedocs.io/en/doc-1.0/bpf/.
+
+Using the XDP_REDIRECT action from an XDP program, the program can
+redirect ingress frames to other XDP enabled netdevs, using the
+bpf_redirect_map() function. AF_XDP sockets enable the possibility for
+XDP programs to redirect frames to a memory buffer in a user-space
+application.
+
+An AF_XDP socket (XSK) is created with the normal socket()
+syscall. Associated with each XSK are two rings: the RX ring and the
+TX ring. A socket can receive packets on the RX ring and it can send
+packets on the TX ring. These rings are registered and sized with the
+setsockopts XDP_RX_RING and XDP_TX_RING, respectively. It is mandatory
+to have at least one of these rings for each socket. An RX or TX
+descriptor ring points to a data buffer in a memory area called a
+UMEM. RX and TX can share the same UMEM so that a packet does not have
+to be copied between RX and TX. Moreover, if a packet needs to be kept
+for a while due to a possible retransmit, the descriptor that points
+to that packet can be changed to point to another and reused right
+away. This again avoids copying data.
+
+The UMEM consists of a number of equally size frames and each frame
+has a unique frame id. A descriptor in one of the rings references a
+frame by referencing its frame id. The user space allocates memory for
+this UMEM using whatever means it feels is most appropriate (malloc,
+mmap, huge pages, etc). This memory area is then registered with the
+kernel using the new setsockopt XDP_UMEM_REG. The UMEM also has two
+rings: the FILL ring and the COMPLETION ring. The fill ring is used by
+the application to send down frame ids for the kernel to fill in with
+RX packet data. References to these frames will then appear in the RX
+ring once each packet has been received. The completion ring, on the
+other hand, contains frame ids that the kernel has transmitted
+completely and can now be used again by user space, for either TX or
+RX. Thus, the frame ids appearing in the completion ring are ids that
+were previously transmitted using the TX ring. In summary, the RX and
+FILL rings are used for the RX path and the TX and COMPLETION rings
+are used for the TX path.
+
+The socket is then finally bound with a bind() call to a device and a
+specific queue id on that device, and it is not until bind is
+completed that traffic starts to flow.
+
+The UMEM can be shared between processes, if desired. If a process
+wants to do this, it simply skips the registration of the UMEM and its
+corresponding two rings, sets the XDP_SHARED_UMEM flag in the bind
+call and submits the XSK of the process it would like to share UMEM
+with as well as its own newly created XSK socket. The new process will
+then receive frame id references in its own RX ring that point to this
+shared UMEM. Note that since the ring structures are single-consumer /
+single-producer (for performance reasons), the new process has to
+create its own socket with associated RX and TX rings, since it cannot
+share this with the other process. This is also the reason that there
+is only one set of FILL and COMPLETION rings per UMEM. It is the
+responsibility of a single process to handle the UMEM.
+
+How is then packets distributed from an XDP program to the XSKs? There
+is a BPF map called XSKMAP (or BPF_MAP_TYPE_XSKMAP in full). The
+user-space application can place an XSK at an arbitrary place in this
+map. The XDP program can then redirect a packet to a specific index in
+this map and at this point XDP validates that the XSK in that map was
+indeed bound to that device and ring number. If not, the packet is
+dropped. If the map is empty at that index, the packet is also
+dropped. This also means that it is currently mandatory to have an XDP
+program loaded (and one XSK in the XSKMAP) to be able to get any
+traffic to user space through the XSK.
+
+AF_XDP can operate in two different modes: XDP_SKB and XDP_DRV. If the
+driver does not have support for XDP, or XDP_SKB is explicitly chosen
+when loading the XDP program, XDP_SKB mode is employed that uses SKBs
+together with the generic XDP support and copies out the data to user
+space. A fallback mode that works for any network device. On the other
+hand, if the driver has support for XDP, it will be used by the AF_XDP
+code to provide better performance, but there is still a copy of the
+data into user space.
+
+Concepts
+========
+
+In order to use an AF_XDP socket, a number of associated objects need
+to be setup.
+
+Jonathan Corbet has also written an excellent article on LWN,
+"Accelerating networking with AF_XDP". It can be found at
+https://lwn.net/Articles/750845/.
+
+UMEM
+----
+
+UMEM is a region of virtual contiguous memory, divided into
+equal-sized frames. An UMEM is associated to a netdev and a specific
+queue id of that netdev. It is created and configured (frame size,
+frame headroom, start address and size) by using the XDP_UMEM_REG
+setsockopt system call. A UMEM is bound to a netdev and queue id, via
+the bind() system call.
+
+An AF_XDP is socket linked to a single UMEM, but one UMEM can have
+multiple AF_XDP sockets. To share an UMEM created via one socket A,
+the next socket B can do this by setting the XDP_SHARED_UMEM flag in
+struct sockaddr_xdp member sxdp_flags, and passing the file descriptor
+of A to struct sockaddr_xdp member sxdp_shared_umem_fd.
+
+The UMEM has two single-producer/single-consumer rings, that are used
+to transfer ownership of UMEM frames between the kernel and the
+user-space application.
+
+Rings
+-----
+
+There are a four different kind of rings: Fill, Completion, RX and
+TX. All rings are single-producer/single-consumer, so the user-space
+application need explicit synchronization of multiple
+processes/threads are reading/writing to them.
+
+The UMEM uses two rings: Fill and Completion. Each socket associated
+with the UMEM must have an RX queue, TX queue or both. Say, that there
+is a setup with four sockets (all doing TX and RX). Then there will be
+one Fill ring, one Completion ring, four TX rings and four RX rings.
+
+The rings are head(producer)/tail(consumer) based rings. A producer
+writes the data ring at the index pointed out by struct xdp_ring
+producer member, and increasing the producer index. A consumer reads
+the data ring at the index pointed out by struct xdp_ring consumer
+member, and increasing the consumer index.
+
+The rings are configured and created via the _RING setsockopt system
+calls and mmapped to user-space using the appropriate offset to mmap()
+(XDP_PGOFF_RX_RING, XDP_PGOFF_TX_RING, XDP_UMEM_PGOFF_FILL_RING and
+XDP_UMEM_PGOFF_COMPLETION_RING).
+
+The size of the rings need to be of size power of two.
+
+UMEM Fill Ring
+~~~~~~~~~~~~~~
+
+The Fill ring is used to transfer ownership of UMEM frames from
+user-space to kernel-space. The UMEM indicies are passed in the
+ring. As an example, if the UMEM is 64k and each frame is 4k, then the
+UMEM has 16 frames and can pass indicies between 0 and 15.
+
+Frames passed to the kernel are used for the ingress path (RX rings).
+
+The user application produces UMEM indicies to this ring.
+
+UMEM Completetion Ring
+~~~~~~~~~~~~~~~~~~~~~~
+
+The Completion Ring is used transfer ownership of UMEM frames from
+kernel-space to user-space. Just like the Fill ring, UMEM indicies are
+used.
+
+Frames passed from the kernel to user-space are frames that has been
+sent (TX ring) and can be used by user-space again.
+
+The user application consumes UMEM indicies from this ring.
+
+
+RX Ring
+~~~~~~~
+
+The RX ring is the receiving side of a socket. Each entry in the ring
+is a struct xdp_desc descriptor. The descriptor contains UMEM index
+(idx), the length of the data (len), the offset into the frame
+(offset).
+
+If no frames have been passed to kernel via the Fill ring, no
+descriptors will (or can) appear on the RX ring.
+
+The user application consumes struct xdp_desc descriptors from this
+ring.
+
+TX Ring
+~~~~~~~
+
+The TX ring is used to send frames. The struct xdp_desc descriptor is
+filled (index, length and offset) and passed into the ring.
+
+To start the transfer a sendmsg() system call is required. This might
+be relaxed in the future.
+
+The user application produces struct xdp_desc descriptors to this
+ring.
+
+XSKMAP / BPF_MAP_TYPE_XSKMAP
+----------------------------
+
+On XDP side there is a BPF map type BPF_MAP_TYPE_XSKMAP (XSKMAP) that
+is used in conjunction with bpf_redirect_map() to pass the ingress
+frame to a socket.
+
+The user application inserts the socket into the map, via the bpf()
+system call.
+
+Note that if an XDP program tries to redirect to a socket that does
+not match the queue configuration and netdev, the frame will be
+dropped. E.g. an AF_XDP socket is bound to netdev eth0 and
+queue 17. Only the XDP program executing for eth0 and queue 17 will
+successfully pass data to the socket. Please refer to the sample
+application (samples/bpf/) in for an example.
+
+Usage
+=====
+
+In order to use AF_XDP sockets there are two parts needed. The
+user-space application and the XDP program. For a complete setup and
+usage example, please refer to the sample application. The user-space
+side is xdpsock_user.c and the XDP side xdpsock_kern.c.
+
+Naive ring dequeue and enqueue could look like this::
+
+ // typedef struct xdp_rxtx_ring RING;
+ // typedef struct xdp_umem_ring RING;
+
+ // typedef struct xdp_desc RING_TYPE;
+ // typedef __u32 RING_TYPE;
+
+ int dequeue_one(RING *ring, RING_TYPE *item)
+ {
+ __u32 entries = ring->ptrs.producer - ring->ptrs.consumer;
+
+ if (entries == 0)
+ return -1;
+
+ // read-barrier!
+
+ *item = ring->desc[ring->ptrs.consumer & (RING_SIZE - 1)];
+ ring->ptrs.consumer++;
+ return 0;
+ }
+
+ int enqueue_one(RING *ring, const RING_TYPE *item)
+ {
+ u32 free_entries = RING_SIZE - (ring->ptrs.producer - ring->ptrs.consumer);
+
+ if (free_entries == 0)
+ return -1;
+
+ ring->desc[ring->ptrs.producer & (RING_SIZE - 1)] = *item;
+
+ // write-barrier!
+
+ ring->ptrs.producer++;
+ return 0;
+ }
+
+
+For a more optimized version, please refer to the sample application.
+
+Sample application
+==================
+
+There is a xdpsock benchmarking/test application included that
+demonstrates how to use AF_XDP sockets with both private and shared
+UMEMs. Say that you would like your UDP traffic from port 4242 to end
+up in queue 16, that we will enable AF_XDP on. Here, we use ethtool
+for this::
+
+ ethtool -N p3p2 rx-flow-hash udp4 fn
+ ethtool -N p3p2 flow-type udp4 src-port 4242 dst-port 4242 \
+ action 16
+
+Running the rxdrop benchmark in XDP_DRV mode can then be done
+using::
+
+ samples/bpf/xdpsock -i p3p2 -q 16 -r -N
+
+For XDP_SKB mode, use the switch "-S" instead of "-N" and all options
+can be displayed with "-h", as usual.
+
+Credits
+=======
+
+- Björn Töpel (AF_XDP core)
+- Magnus Karlsson (AF_XDP core)
+- Alexander Duyck
+- Alexei Starovoitov
+- Daniel Borkmann
+- Jesper Dangaard Brouer
+- John Fastabend
+- Jonathan Corbet (LWN coverage)
+- Michael S. Tsirkin
+- Qi Z Zhang
+- Willem de Bruijn
+
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2017 - 2018 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <getopt.h>
+#include <libgen.h>
+#include <linux/bpf.h>
+#include <linux/if_link.h>
+#include <linux/if_xdp.h>
+#include <linux/if_ether.h>
+#include <net/if.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <net/ethernet.h>
+#include <sys/resource.h>
+#include <sys/socket.h>
+#include <sys/mman.h>
+#include <time.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <locale.h>
+#include <sys/types.h>
+#include <poll.h>
+
+#include "bpf_load.h"
+#include "bpf_util.h"
+#include "libbpf.h"
+
+#include "xdpsock.h"
+
+#ifndef SOL_XDP
+#define SOL_XDP 283
+#endif
+
+#ifndef AF_XDP
+#define AF_XDP 44
+#endif
+
+#ifndef PF_XDP
+#define PF_XDP AF_XDP
+#endif
+
+#define NUM_FRAMES 131072
+#define FRAME_HEADROOM 0
+#define FRAME_SIZE 2048
+#define NUM_DESCS 1024
+#define BATCH_SIZE 16
+
+#define FQ_NUM_DESCS 1024
+#define CQ_NUM_DESCS 1024
+
+#define DEBUG_HEXDUMP 0
+
+typedef __u32 u32;
+
+static unsigned long prev_time;
+
+enum benchmark_type {
+ BENCH_RXDROP = 0,
+ BENCH_TXONLY = 1,
+ BENCH_L2FWD = 2,
+};
+
+static enum benchmark_type opt_bench = BENCH_RXDROP;
+static u32 opt_xdp_flags;
+static const char *opt_if = "";
+static int opt_ifindex;
+static int opt_queue;
+static int opt_poll;
+static int opt_shared_packet_buffer;
+static int opt_interval = 1;
+
+struct xdp_umem_uqueue {
+ u32 cached_prod;
+ u32 cached_cons;
+ u32 mask;
+ u32 size;
+ struct xdp_umem_ring *ring;
+};
+
+struct xdp_umem {
+ char (*frames)[FRAME_SIZE];
+ struct xdp_umem_uqueue fq;
+ struct xdp_umem_uqueue cq;
+ int fd;
+};
+
+struct xdp_uqueue {
+ u32 cached_prod;
+ u32 cached_cons;
+ u32 mask;
+ u32 size;
+ struct xdp_rxtx_ring *ring;
+};
+
+struct xdpsock {
+ struct xdp_uqueue rx;
+ struct xdp_uqueue tx;
+ int sfd;
+ struct xdp_umem *umem;
+ u32 outstanding_tx;
+ unsigned long rx_npkts;
+ unsigned long tx_npkts;
+ unsigned long prev_rx_npkts;
+ unsigned long prev_tx_npkts;
+};
+
+#define MAX_SOCKS 4
+static int num_socks;
+struct xdpsock *xsks[MAX_SOCKS];
+
+static unsigned long get_nsecs(void)
+{
+ struct timespec ts;
+
+ clock_gettime(CLOCK_MONOTONIC, &ts);
+ return ts.tv_sec * 1000000000UL + ts.tv_nsec;
+}
+
+static void dump_stats(void);
+
+#define lassert(expr) \
+ do { \
+ if (!(expr)) { \
+ fprintf(stderr, "%s:%s:%i: Assertion failed: " \
+ #expr ": errno: %d/\"%s\"\n", \
+ __FILE__, __func__, __LINE__, \
+ errno, strerror(errno)); \
+ dump_stats(); \
+ exit(EXIT_FAILURE); \
+ } \
+ } while (0)
+
+#define barrier() __asm__ __volatile__("": : :"memory")
+#define u_smp_rmb() barrier()
+#define u_smp_wmb() barrier()
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+static const char pkt_data[] =
+ "\x3c\xfd\xfe\x9e\x7f\x71\xec\xb1\xd7\x98\x3a\xc0\x08\x00\x45\x00"
+ "\x00\x2e\x00\x00\x00\x00\x40\x11\x88\x97\x05\x08\x07\x08\xc8\x14"
+ "\x1e\x04\x10\x92\x10\x92\x00\x1a\x6d\xa3\x34\x33\x1f\x69\x40\x6b"
+ "\x54\x59\xb6\x14\x2d\x11\x44\xbf\xaf\xd9\xbe\xaa";
+
+static inline u32 umem_nb_free(struct xdp_umem_uqueue *q, u32 nb)
+{
+ u32 free_entries = q->size - (q->cached_prod - q->cached_cons);
+
+ if (free_entries >= nb)
+ return free_entries;
+
+ /* Refresh the local tail pointer */
+ q->cached_cons = q->ring->ptrs.consumer;
+
+ return q->size - (q->cached_prod - q->cached_cons);
+}
+
+static inline u32 xq_nb_free(struct xdp_uqueue *q, u32 ndescs)
+{
+ u32 free_entries = q->cached_cons - q->cached_prod;
+
+ if (free_entries >= ndescs)
+ return free_entries;
+
+ /* Refresh the local tail pointer */
+ q->cached_cons = q->ring->ptrs.consumer + q->size;
+ return q->cached_cons - q->cached_prod;
+}
+
+static inline u32 umem_nb_avail(struct xdp_umem_uqueue *q, u32 nb)
+{
+ u32 entries = q->cached_prod - q->cached_cons;
+
+ if (entries == 0) {
+ q->cached_prod = q->ring->ptrs.producer;
+ entries = q->cached_prod - q->cached_cons;
+ }
+
+ return (entries > nb) ? nb : entries;
+}
+
+static inline u32 xq_nb_avail(struct xdp_uqueue *q, u32 ndescs)
+{
+ u32 entries = q->cached_prod - q->cached_cons;
+
+ if (entries == 0) {
+ q->cached_prod = q->ring->ptrs.producer;
+ entries = q->cached_prod - q->cached_cons;
+ }
+
+ return (entries > ndescs) ? ndescs : entries;
+}
+
+static inline int umem_fill_to_kernel_ex(struct xdp_umem_uqueue *fq,
+ struct xdp_desc *d,
+ size_t nb)
+{
+ u32 i;
+
+ if (umem_nb_free(fq, nb) < nb)
+ return -ENOSPC;
+
+ for (i = 0; i < nb; i++) {
+ u32 idx = fq->cached_prod++ & fq->mask;
+
+ fq->ring->desc[idx] = d[i].idx;
+ }
+
+ u_smp_wmb();
+
+ fq->ring->ptrs.producer = fq->cached_prod;
+
+ return 0;
+}
+
+static inline int umem_fill_to_kernel(struct xdp_umem_uqueue *fq, u32 *d,
+ size_t nb)
+{
+ u32 i;
+
+ if (umem_nb_free(fq, nb) < nb)
+ return -ENOSPC;
+
+ for (i = 0; i < nb; i++) {
+ u32 idx = fq->cached_prod++ & fq->mask;
+
+ fq->ring->desc[idx] = d[i];
+ }
+
+ u_smp_wmb();
+
+ fq->ring->ptrs.producer = fq->cached_prod;
+
+ return 0;
+}
+
+static inline size_t umem_complete_from_kernel(struct xdp_umem_uqueue *cq,
+ u32 *d, size_t nb)
+{
+ u32 idx, i, entries = umem_nb_avail(cq, nb);
+
+ u_smp_rmb();
+
+ for (i = 0; i < entries; i++) {
+ idx = cq->cached_cons++ & cq->mask;
+ d[i] = cq->ring->desc[idx];
+ }
+
+ if (entries > 0) {
+ u_smp_wmb();
+
+ cq->ring->ptrs.consumer = cq->cached_cons;
+ }
+
+ return entries;
+}
+
+static inline void *xq_get_data(struct xdpsock *xsk, __u32 idx, __u32 off)
+{
+ lassert(idx < NUM_FRAMES);
+ return &xsk->umem->frames[idx][off];
+}
+
+static inline int xq_enq(struct xdp_uqueue *uq,
+ const struct xdp_desc *descs,
+ unsigned int ndescs)
+{
+ struct xdp_rxtx_ring *r = uq->ring;
+ unsigned int i;
+
+ if (xq_nb_free(uq, ndescs) < ndescs)
+ return -ENOSPC;
+
+ for (i = 0; i < ndescs; i++) {
+ u32 idx = uq->cached_prod++ & uq->mask;
+
+ r->desc[idx].idx = descs[i].idx;
+ r->desc[idx].len = descs[i].len;
+ r->desc[idx].offset = descs[i].offset;
+ }
+
+ u_smp_wmb();
+
+ r->ptrs.producer = uq->cached_prod;
+ return 0;
+}
+
+static inline int xq_enq_tx_only(struct xdp_uqueue *uq,
+ __u32 idx, unsigned int ndescs)
+{
+ struct xdp_rxtx_ring *q = uq->ring;
+ unsigned int i;
+
+ if (xq_nb_free(uq, ndescs) < ndescs)
+ return -ENOSPC;
+
+ for (i = 0; i < ndescs; i++) {
+ u32 idx = uq->cached_prod++ & uq->mask;
+
+ q->desc[idx].idx = idx + i;
+ q->desc[idx].len = sizeof(pkt_data) - 1;
+ q->desc[idx].offset = 0;
+ }
+
+ u_smp_wmb();
+
+ q->ptrs.producer = uq->cached_prod;
+ return 0;
+}
+
+static inline int xq_deq(struct xdp_uqueue *uq,
+ struct xdp_desc *descs,
+ int ndescs)
+{
+ struct xdp_rxtx_ring *r = uq->ring;
+ unsigned int idx;
+ int i, entries;
+
+ entries = xq_nb_avail(uq, ndescs);
+
+ u_smp_rmb();
+
+ for (i = 0; i < entries; i++) {
+ idx = uq->cached_cons++ & uq->mask;
+ descs[i] = r->desc[idx];
+ }
+
+ if (entries > 0) {
+ u_smp_wmb();
+
+ r->ptrs.consumer = uq->cached_cons;
+ }
+
+ return entries;
+}
+
+static void swap_mac_addresses(void *data)
+{
+ struct ether_header *eth = (struct ether_header *)data;
+ struct ether_addr *src_addr = (struct ether_addr *)ð->ether_shost;
+ struct ether_addr *dst_addr = (struct ether_addr *)ð->ether_dhost;
+ struct ether_addr tmp;
+
+ tmp = *src_addr;
+ *src_addr = *dst_addr;
+ *dst_addr = tmp;
+}
+
+#if DEBUG_HEXDUMP
+static void hex_dump(void *pkt, size_t length, const char *prefix)
+{
+ int i = 0;
+ const unsigned char *address = (unsigned char *)pkt;
+ const unsigned char *line = address;
+ size_t line_size = 32;
+ unsigned char c;
+
+ printf("length = %zu\n", length);
+ printf("%s | ", prefix);
+ while (length-- > 0) {
+ printf("%02X ", *address++);
+ if (!(++i % line_size) || (length == 0 && i % line_size)) {
+ if (length == 0) {
+ while (i++ % line_size)
+ printf("__ ");
+ }
+ printf(" | "); /* right close */
+ while (line < address) {
+ c = *line++;
+ printf("%c", (c < 33 || c == 255) ? 0x2E : c);
+ }
+ printf("\n");
+ if (length > 0)
+ printf("%s | ", prefix);
+ }
+ }
+ printf("\n");
+}
+#endif
+
+static size_t gen_eth_frame(char *frame)
+{
+ memcpy(frame, pkt_data, sizeof(pkt_data) - 1);
+ return sizeof(pkt_data) - 1;
+}
+
+static struct xdp_umem *xdp_umem_configure(int sfd)
+{
+ int fq_size = FQ_NUM_DESCS, cq_size = CQ_NUM_DESCS;
+ struct xdp_umem_reg mr;
+ struct xdp_umem *umem;
+ void *bufs;
+
+ umem = calloc(1, sizeof(*umem));
+ lassert(umem);
+
+ lassert(posix_memalign(&bufs, getpagesize(), /* PAGE_SIZE aligned */
+ NUM_FRAMES * FRAME_SIZE) == 0);
+
+ mr.addr = (__u64)bufs;
+ mr.len = NUM_FRAMES * FRAME_SIZE;
+ mr.frame_size = FRAME_SIZE;
+ mr.frame_headroom = FRAME_HEADROOM;
+
+ lassert(setsockopt(sfd, SOL_XDP, XDP_UMEM_REG, &mr, sizeof(mr)) == 0);
+ lassert(setsockopt(sfd, SOL_XDP, XDP_UMEM_FILL_RING, &fq_size,
+ sizeof(int)) == 0);
+ lassert(setsockopt(sfd, SOL_XDP, XDP_UMEM_COMPLETION_RING, &cq_size,
+ sizeof(int)) == 0);
+
+ umem->fq.ring = mmap(0, sizeof(struct xdp_umem_ring) +
+ FQ_NUM_DESCS * sizeof(u32),
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, sfd,
+ XDP_UMEM_PGOFF_FILL_RING);
+ lassert(umem->fq.ring != MAP_FAILED);
+
+ umem->fq.mask = FQ_NUM_DESCS - 1;
+ umem->fq.size = FQ_NUM_DESCS;
+
+ umem->cq.ring = mmap(0, sizeof(struct xdp_umem_ring) +
+ CQ_NUM_DESCS * sizeof(u32),
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, sfd,
+ XDP_UMEM_PGOFF_COMPLETION_RING);
+ lassert(umem->cq.ring != MAP_FAILED);
+
+ umem->cq.mask = CQ_NUM_DESCS - 1;
+ umem->cq.size = CQ_NUM_DESCS;
+
+ umem->frames = (char (*)[FRAME_SIZE])bufs;
+ umem->fd = sfd;
+
+ if (opt_bench == BENCH_TXONLY) {
+ int i;
+
+ for (i = 0; i < NUM_FRAMES; i++)
+ (void)gen_eth_frame(&umem->frames[i][0]);
+ }
+
+ return umem;
+}
+
+static struct xdpsock *xsk_configure(struct xdp_umem *umem)
+{
+ struct sockaddr_xdp sxdp = {};
+ int sfd, ndescs = NUM_DESCS;
+ struct xdpsock *xsk;
+ bool shared = true;
+ u32 i;
+
+ sfd = socket(PF_XDP, SOCK_RAW, 0);
+ lassert(sfd >= 0);
+
+ xsk = calloc(1, sizeof(*xsk));
+ lassert(xsk);
+
+ xsk->sfd = sfd;
+ xsk->outstanding_tx = 0;
+
+ if (!umem) {
+ shared = false;
+ xsk->umem = xdp_umem_configure(sfd);
+ } else {
+ xsk->umem = umem;
+ }
+
+ lassert(setsockopt(sfd, SOL_XDP, XDP_RX_RING,
+ &ndescs, sizeof(int)) == 0);
+ lassert(setsockopt(sfd, SOL_XDP, XDP_TX_RING,
+ &ndescs, sizeof(int)) == 0);
+
+ /* Rx */
+ xsk->rx.ring = mmap(NULL,
+ sizeof(struct xdp_ring) +
+ NUM_DESCS * sizeof(struct xdp_desc),
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, sfd,
+ XDP_PGOFF_RX_RING);
+ lassert(xsk->rx.ring != MAP_FAILED);
+
+ if (!shared) {
+ for (i = 0; i < NUM_DESCS / 2; i++)
+ lassert(umem_fill_to_kernel(&xsk->umem->fq, &i, 1)
+ == 0);
+ }
+
+ /* Tx */
+ xsk->tx.ring = mmap(NULL,
+ sizeof(struct xdp_ring) +
+ NUM_DESCS * sizeof(struct xdp_desc),
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, sfd,
+ XDP_PGOFF_TX_RING);
+ lassert(xsk->tx.ring != MAP_FAILED);
+
+ xsk->rx.mask = NUM_DESCS - 1;
+ xsk->rx.size = NUM_DESCS;
+
+ xsk->tx.mask = NUM_DESCS - 1;
+ xsk->tx.size = NUM_DESCS;
+
+ sxdp.sxdp_family = PF_XDP;
+ sxdp.sxdp_ifindex = opt_ifindex;
+ sxdp.sxdp_queue_id = opt_queue;
+ if (shared) {
+ sxdp.sxdp_flags = XDP_SHARED_UMEM;
+ sxdp.sxdp_shared_umem_fd = umem->fd;
+ }
+
+ lassert(bind(sfd, (struct sockaddr *)&sxdp, sizeof(sxdp)) == 0);
+
+ return xsk;
+}
+
+static void print_benchmark(bool running)
+{
+ const char *bench_str = "INVALID";
+
+ if (opt_bench == BENCH_RXDROP)
+ bench_str = "rxdrop";
+ else if (opt_bench == BENCH_TXONLY)
+ bench_str = "txonly";
+ else if (opt_bench == BENCH_L2FWD)
+ bench_str = "l2fwd";
+
+ printf("%s:%d %s ", opt_if, opt_queue, bench_str);
+ if (opt_xdp_flags & XDP_FLAGS_SKB_MODE)
+ printf("xdp-skb ");
+ else if (opt_xdp_flags & XDP_FLAGS_DRV_MODE)
+ printf("xdp-drv ");
+ else
+ printf(" ");
+
+ if (opt_poll)
+ printf("poll() ");
+
+ if (running) {
+ printf("running...");
+ fflush(stdout);
+ }
+}
+
+static void dump_stats(void)
+{
+ unsigned long now = get_nsecs();
+ long dt = now - prev_time;
+ int i;
+
+ prev_time = now;
+
+ for (i = 0; i < num_socks; i++) {
+ char *fmt = "%-15s %'-11.0f %'-11lu\n";
+ double rx_pps, tx_pps;
+
+ rx_pps = (xsks[i]->rx_npkts - xsks[i]->prev_rx_npkts) *
+ 1000000000. / dt;
+ tx_pps = (xsks[i]->tx_npkts - xsks[i]->prev_tx_npkts) *
+ 1000000000. / dt;
+
+ printf("\n sock%d@", i);
+ print_benchmark(false);
+ printf("\n");
+
+ printf("%-15s %-11s %-11s %-11.2f\n", "", "pps", "pkts",
+ dt / 1000000000.);
+ printf(fmt, "rx", rx_pps, xsks[i]->rx_npkts);
+ printf(fmt, "tx", tx_pps, xsks[i]->tx_npkts);
+
+ xsks[i]->prev_rx_npkts = xsks[i]->rx_npkts;
+ xsks[i]->prev_tx_npkts = xsks[i]->tx_npkts;
+ }
+}
+
+static void *poller(void *arg)
+{
+ (void)arg;
+ for (;;) {
+ sleep(opt_interval);
+ dump_stats();
+ }
+
+ return NULL;
+}
+
+static void int_exit(int sig)
+{
+ (void)sig;
+ dump_stats();
+ bpf_set_link_xdp_fd(opt_ifindex, -1, opt_xdp_flags);
+ exit(EXIT_SUCCESS);
+}
+
+static struct option long_options[] = {
+ {"rxdrop", no_argument, 0, 'r'},
+ {"txonly", no_argument, 0, 't'},
+ {"l2fwd", no_argument, 0, 'l'},
+ {"interface", required_argument, 0, 'i'},
+ {"queue", required_argument, 0, 'q'},
+ {"poll", no_argument, 0, 'p'},
+ {"shared-buffer", no_argument, 0, 's'},
+ {"xdp-skb", no_argument, 0, 'S'},
+ {"xdp-native", no_argument, 0, 'N'},
+ {"interval", required_argument, 0, 'n'},
+ {0, 0, 0, 0}
+};
+
+static void usage(const char *prog)
+{
+ const char *str =
+ " Usage: %s [OPTIONS]\n"
+ " Options:\n"
+ " -r, --rxdrop Discard all incoming packets (default)\n"
+ " -t, --txonly Only send packets\n"
+ " -l, --l2fwd MAC swap L2 forwarding\n"
+ " -i, --interface=n Run on interface n\n"
+ " -q, --queue=n Use queue n (default 0)\n"
+ " -p, --poll Use poll syscall\n"
+ " -s, --shared-buffer Use shared packet buffer\n"
+ " -S, --xdp-skb=n Use XDP skb-mod\n"
+ " -N, --xdp-native=n Enfore XDP native mode\n"
+ " -n, --interval=n Specify statistics update interval (default 1 sec).\n"
+ "\n";
+ fprintf(stderr, str, prog);
+ exit(EXIT_FAILURE);
+}
+
+static void parse_command_line(int argc, char **argv)
+{
+ int option_index, c;
+
+ opterr = 0;
+
+ for (;;) {
+ c = getopt_long(argc, argv, "rtli:q:psSNn:", long_options,
+ &option_index);
+ if (c == -1)
+ break;
+
+ switch (c) {
+ case 'r':
+ opt_bench = BENCH_RXDROP;
+ break;
+ case 't':
+ opt_bench = BENCH_TXONLY;
+ break;
+ case 'l':
+ opt_bench = BENCH_L2FWD;
+ break;
+ case 'i':
+ opt_if = optarg;
+ break;
+ case 'q':
+ opt_queue = atoi(optarg);
+ break;
+ case 's':
+ opt_shared_packet_buffer = 1;
+ break;
+ case 'p':
+ opt_poll = 1;
+ break;
+ case 'S':
+ opt_xdp_flags |= XDP_FLAGS_SKB_MODE;
+ break;
+ case 'N':
+ opt_xdp_flags |= XDP_FLAGS_DRV_MODE;
+ break;
+ case 'n':
+ opt_interval = atoi(optarg);
+ break;
+ default:
+ usage(basename(argv[0]));
+ }
+ }
+
+ opt_ifindex = if_nametoindex(opt_if);
+ if (!opt_ifindex) {
+ fprintf(stderr, "ERROR: interface \"%s\" does not exist\n",
+ opt_if);
+ usage(basename(argv[0]));
+ }
+}
+
+static void kick_tx(int fd)
+{
+ int ret;
+
+ ret = sendto(fd, NULL, 0, MSG_DONTWAIT, NULL, 0);
+ if (ret >= 0 || errno == ENOBUFS || errno == EAGAIN)
+ return;
+ lassert(0);
+}
+
+static inline void complete_tx_l2fwd(struct xdpsock *xsk)
+{
+ u32 descs[BATCH_SIZE];
+ unsigned int rcvd;
+ size_t ndescs;
+
+ if (!xsk->outstanding_tx)
+ return;
+
+ kick_tx(xsk->sfd);
+ ndescs = (xsk->outstanding_tx > BATCH_SIZE) ? BATCH_SIZE :
+ xsk->outstanding_tx;
+
+ /* re-add completed Tx buffers */
+ rcvd = umem_complete_from_kernel(&xsk->umem->cq, descs, ndescs);
+ if (rcvd > 0) {
+ umem_fill_to_kernel(&xsk->umem->fq, descs, rcvd);
+ xsk->outstanding_tx -= rcvd;
+ xsk->tx_npkts += rcvd;
+ }
+}
+
+static inline void complete_tx_only(struct xdpsock *xsk)
+{
+ u32 descs[BATCH_SIZE];
+ unsigned int rcvd;
+
+ if (!xsk->outstanding_tx)
+ return;
+
+ kick_tx(xsk->sfd);
+
+ rcvd = umem_complete_from_kernel(&xsk->umem->cq, descs, BATCH_SIZE);
+ if (rcvd > 0) {
+ xsk->outstanding_tx -= rcvd;
+ xsk->tx_npkts += rcvd;
+ }
+}
+
+static void rx_drop(struct xdpsock *xsk)
+{
+ struct xdp_desc descs[BATCH_SIZE];
+ unsigned int rcvd, i;
+
+ rcvd = xq_deq(&xsk->rx, descs, BATCH_SIZE);
+ if (!rcvd)
+ return;
+
+ for (i = 0; i < rcvd; i++) {
+ u32 idx = descs[i].idx;
+
+ lassert(idx < NUM_FRAMES);
+#if DEBUG_HEXDUMP
+ char *pkt;
+ char buf[32];
+
+ pkt = xq_get_data(xsk, idx, descs[i].offset);
+ sprintf(buf, "idx=%d", idx);
+ hex_dump(pkt, descs[i].len, buf);
+#endif
+ }
+
+ xsk->rx_npkts += rcvd;
+
+ umem_fill_to_kernel_ex(&xsk->umem->fq, descs, rcvd);
+}
+
+static void rx_drop_all(void)
+{
+ struct pollfd fds[MAX_SOCKS + 1];
+ int i, ret, timeout, nfds = 1;
+
+ memset(fds, 0, sizeof(fds));
+
+ for (i = 0; i < num_socks; i++) {
+ fds[i].fd = xsks[i]->sfd;
+ fds[i].events = POLLIN;
+ timeout = 1000; /* 1sn */
+ }
+
+ for (;;) {
+ if (opt_poll) {
+ ret = poll(fds, nfds, timeout);
+ if (ret <= 0)
+ continue;
+ }
+
+ for (i = 0; i < num_socks; i++)
+ rx_drop(xsks[i]);
+ }
+}
+
+static void tx_only(struct xdpsock *xsk)
+{
+ int timeout, ret, nfds = 1;
+ struct pollfd fds[nfds + 1];
+ unsigned int idx = 0;
+
+ memset(fds, 0, sizeof(fds));
+ fds[0].fd = xsk->sfd;
+ fds[0].events = POLLOUT;
+ timeout = 1000; /* 1sn */
+
+ for (;;) {
+ if (opt_poll) {
+ ret = poll(fds, nfds, timeout);
+ if (ret <= 0)
+ continue;
+
+ if (fds[0].fd != xsk->sfd ||
+ !(fds[0].revents & POLLOUT))
+ continue;
+ }
+
+ if (xq_nb_free(&xsk->tx, BATCH_SIZE) >= BATCH_SIZE) {
+ lassert(xq_enq_tx_only(&xsk->tx, idx, BATCH_SIZE) == 0);
+
+ xsk->outstanding_tx += BATCH_SIZE;
+ idx += BATCH_SIZE;
+ idx %= NUM_FRAMES;
+ }
+
+ complete_tx_only(xsk);
+ }
+}
+
+static void l2fwd(struct xdpsock *xsk)
+{
+ for (;;) {
+ struct xdp_desc descs[BATCH_SIZE];
+ unsigned int rcvd, i;
+ int ret;
+
+ for (;;) {
+ complete_tx_l2fwd(xsk);
+
+ rcvd = xq_deq(&xsk->rx, descs, BATCH_SIZE);
+ if (rcvd > 0)
+ break;
+ }
+
+ for (i = 0; i < rcvd; i++) {
+ char *pkt = xq_get_data(xsk, descs[i].idx,
+ descs[i].offset);
+
+ swap_mac_addresses(pkt);
+#if DEBUG_HEXDUMP
+ char buf[32];
+ u32 idx = descs[i].idx;
+
+ sprintf(buf, "idx=%d", idx);
+ hex_dump(pkt, descs[i].len, buf);
+#endif
+ }
+
+ xsk->rx_npkts += rcvd;
+
+ ret = xq_enq(&xsk->tx, descs, rcvd);
+ lassert(ret == 0);
+ xsk->outstanding_tx += rcvd;
+ }
+}
+
+int main(int argc, char **argv)
+{
+ struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ char xdp_filename[256];
+ int i, ret, key = 0;
+ pthread_t pt;
+
+ parse_command_line(argc, argv);
+
+ if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+ fprintf(stderr, "ERROR: setrlimit(RLIMIT_MEMLOCK) \"%s\"\n",
+ strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+
+ snprintf(xdp_filename, sizeof(xdp_filename), "%s_kern.o", argv[0]);
+
+ if (load_bpf_file(xdp_filename)) {
+ fprintf(stderr, "ERROR: load_bpf_file %s\n", bpf_log_buf);
+ exit(EXIT_FAILURE);
+ }
+
+ if (!prog_fd[0]) {
+ fprintf(stderr, "ERROR: load_bpf_file: \"%s\"\n",
+ strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+
+ if (bpf_set_link_xdp_fd(opt_ifindex, prog_fd[0], opt_xdp_flags) < 0) {
+ fprintf(stderr, "ERROR: link set xdp fd failed\n");
+ exit(EXIT_FAILURE);
+ }
+
+ ret = bpf_map_update_elem(map_fd[0], &key, &opt_queue, 0);
+ if (ret) {
+ fprintf(stderr, "ERROR: bpf_map_update_elem qidconf\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Create sockets... */
+ xsks[num_socks++] = xsk_configure(NULL);
+
+#if RR_LB
+ for (i = 0; i < MAX_SOCKS - 1; i++)
+ xsks[num_socks++] = xsk_configure(xsks[0]->umem);
+#endif
+
+ /* ...and insert them into the map. */
+ for (i = 0; i < num_socks; i++) {
+ key = i;
+ ret = bpf_map_update_elem(map_fd[1], &key, &xsks[i]->sfd, 0);
+ if (ret) {
+ fprintf(stderr, "ERROR: bpf_map_update_elem %d\n", i);
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+ signal(SIGABRT, int_exit);
+
+ setlocale(LC_ALL, "");
+
+ ret = pthread_create(&pt, NULL, poller, NULL);
+ lassert(ret == 0);
+
+ prev_time = get_nsecs();
+
+ if (opt_bench == BENCH_RXDROP)
+ rx_drop_all();
+ else if (opt_bench == BENCH_TXONLY)
+ tx_only(xsks[0]);
+ else
+ l2fwd(xsks[0]);
+
+ return 0;
+}
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