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Date: Fri, 8 Nov 2019 10:13:30 -0800
From: William Tu <u9012063@...il.com>
To: Magnus Karlsson <magnus.karlsson@...el.com>
Cc: bjorn.topel@...el.com, ast@...nel.org, daniel@...earbox.net,
netdev@...r.kernel.org, jonathan.lemon@...il.com,
bpf@...r.kernel.org
Subject: Re: [PATCH bpf-next 2/5] samples/bpf: add XDP_SHARED_UMEM support to
xdpsock
On Thu, Nov 07, 2019 at 06:47:37PM +0100, Magnus Karlsson wrote:
> Add support for the XDP_SHARED_UMEM mode to the xdpsock sample
> application. As libbpf does not have a built in XDP program for this
> mode, we use an explicitly loaded XDP program. This also serves as an
> example on how to write your own XDP program that can route to an
> AF_XDP socket.
>
> Signed-off-by: Magnus Karlsson <magnus.karlsson@...el.com>
> ---
> samples/bpf/Makefile | 1 +
> samples/bpf/xdpsock.h | 11 ++++
> samples/bpf/xdpsock_kern.c | 24 ++++++++
> samples/bpf/xdpsock_user.c | 141 +++++++++++++++++++++++++++++++--------------
> 4 files changed, 135 insertions(+), 42 deletions(-)
> create mode 100644 samples/bpf/xdpsock.h
> create mode 100644 samples/bpf/xdpsock_kern.c
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 4df11dd..8a9af3a 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -167,6 +167,7 @@ always += xdp_sample_pkts_kern.o
> always += ibumad_kern.o
> always += hbm_out_kern.o
> always += hbm_edt_kern.o
> +always += xdpsock_kern.o
>
> ifeq ($(ARCH), arm)
> # Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
> diff --git a/samples/bpf/xdpsock.h b/samples/bpf/xdpsock.h
> new file mode 100644
> index 0000000..b7eca15
> --- /dev/null
> +++ b/samples/bpf/xdpsock.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * Copyright(c) 2019 Intel Corporation.
> + */
> +
> +#ifndef XDPSOCK_H_
> +#define XDPSOCK_H_
> +
> +#define MAX_SOCKS 4
> +
> +#endif /* XDPSOCK_H */
> diff --git a/samples/bpf/xdpsock_kern.c b/samples/bpf/xdpsock_kern.c
> new file mode 100644
> index 0000000..a06177c
> --- /dev/null
> +++ b/samples/bpf/xdpsock_kern.c
> @@ -0,0 +1,24 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bpf.h>
> +#include "bpf_helpers.h"
> +#include "xdpsock.h"
> +
> +/* This XDP program is only needed for the XDP_SHARED_UMEM mode.
> + * If you do not use this mode, libbpf can supply an XDP program for you.
> + */
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_XSKMAP);
> + __uint(max_entries, MAX_SOCKS);
> + __uint(key_size, sizeof(int));
> + __uint(value_size, sizeof(int));
> +} xsks_map SEC(".maps");
> +
> +static unsigned int rr;
> +
> +SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
> +{
> + rr = (rr + 1) & (MAX_SOCKS - 1);
> +
> + return bpf_redirect_map(&xsks_map, rr, XDP_DROP);
> +}
> diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
> index 405c4e0..d3dba93 100644
> --- a/samples/bpf/xdpsock_user.c
> +++ b/samples/bpf/xdpsock_user.c
> @@ -29,6 +29,7 @@
>
> #include "libbpf.h"
> #include "xsk.h"
> +#include "xdpsock.h"
> #include <bpf/bpf.h>
>
> #ifndef SOL_XDP
> @@ -47,7 +48,6 @@
> #define BATCH_SIZE 64
>
> #define DEBUG_HEXDUMP 0
> -#define MAX_SOCKS 8
>
> typedef __u64 u64;
> typedef __u32 u32;
> @@ -75,7 +75,8 @@ static u32 opt_xdp_bind_flags;
> static int opt_xsk_frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
> static int opt_timeout = 1000;
> static bool opt_need_wakeup = true;
> -static __u32 prog_id;
> +static u32 opt_num_xsks = 1;
> +static u32 prog_id;
>
> struct xsk_umem_info {
> struct xsk_ring_prod fq;
> @@ -179,7 +180,7 @@ static void *poller(void *arg)
>
> static void remove_xdp_program(void)
> {
> - __u32 curr_prog_id = 0;
> + u32 curr_prog_id = 0;
>
> if (bpf_get_link_xdp_id(opt_ifindex, &curr_prog_id, opt_xdp_flags)) {
> printf("bpf_get_link_xdp_id failed\n");
> @@ -196,11 +197,11 @@ static void remove_xdp_program(void)
> static void int_exit(int sig)
> {
> struct xsk_umem *umem = xsks[0]->umem->umem;
> -
> - (void)sig;
> + int i;
>
> dump_stats();
> - xsk_socket__delete(xsks[0]->xsk);
> + for (i = 0; i < num_socks; i++)
> + xsk_socket__delete(xsks[i]->xsk);
> (void)xsk_umem__delete(umem);
> remove_xdp_program();
>
> @@ -290,8 +291,8 @@ static struct xsk_umem_info *xsk_configure_umem(void *buffer, u64 size)
> .frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM,
> .flags = opt_umem_flags
> };
> -
> - int ret;
> + int ret, i;
> + u32 idx;
>
> umem = calloc(1, sizeof(*umem));
> if (!umem)
> @@ -303,6 +304,15 @@ static struct xsk_umem_info *xsk_configure_umem(void *buffer, u64 size)
> if (ret)
> exit_with_error(-ret);
>
> + ret = xsk_ring_prod__reserve(&umem->fq,
> + XSK_RING_PROD__DEFAULT_NUM_DESCS, &idx);
> + if (ret != XSK_RING_PROD__DEFAULT_NUM_DESCS)
> + exit_with_error(-ret);
> + for (i = 0; i < XSK_RING_PROD__DEFAULT_NUM_DESCS; i++)
> + *xsk_ring_prod__fill_addr(&umem->fq, idx++) =
> + i * opt_xsk_frame_size;
> + xsk_ring_prod__submit(&umem->fq, XSK_RING_PROD__DEFAULT_NUM_DESCS);
> +
> umem->buffer = buffer;
> return umem;
> }
> @@ -312,8 +322,6 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem)
> struct xsk_socket_config cfg;
> struct xsk_socket_info *xsk;
> int ret;
> - u32 idx;
> - int i;
>
> xsk = calloc(1, sizeof(*xsk));
> if (!xsk)
> @@ -322,11 +330,15 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem)
> xsk->umem = umem;
> cfg.rx_size = XSK_RING_CONS__DEFAULT_NUM_DESCS;
> cfg.tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS;
> - cfg.libbpf_flags = 0;
> + if (opt_num_xsks > 1)
> + cfg.libbpf_flags = XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD;
I think we can still load our own XDP program, and don't set
XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD.
So the xsk_setup_xdp_prog() will find the the loaded XDP program
and sets the xsk map.
> + else
> + cfg.libbpf_flags = 0;
> cfg.xdp_flags = opt_xdp_flags;
> cfg.bind_flags = opt_xdp_bind_flags;
Do we need to
cfg.bind_flags |= XDP_SHARED_UMEM?
Thanks
William
> - ret = xsk_socket__create(&xsk->xsk, opt_if, opt_queue, umem->umem,
> - &xsk->rx, &xsk->tx, &cfg);
> +
> + ret = xsk_socket__create(&xsk->xsk, opt_if, opt_queue,
> + umem->umem, &xsk->rx, &xsk->tx, &cfg);
> if (ret)
> exit_with_error(-ret);
>
> @@ -334,17 +346,6 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem)
> if (ret)
> exit_with_error(-ret);
>
> - ret = xsk_ring_prod__reserve(&xsk->umem->fq,
> - XSK_RING_PROD__DEFAULT_NUM_DESCS,
> - &idx);
> - if (ret != XSK_RING_PROD__DEFAULT_NUM_DESCS)
> - exit_with_error(-ret);
> - for (i = 0; i < XSK_RING_PROD__DEFAULT_NUM_DESCS; i++)
> - *xsk_ring_prod__fill_addr(&xsk->umem->fq, idx++) =
> - i * opt_xsk_frame_size;
> - xsk_ring_prod__submit(&xsk->umem->fq,
> - XSK_RING_PROD__DEFAULT_NUM_DESCS);
> -
> return xsk;
> }
>
> @@ -363,6 +364,7 @@ static struct option long_options[] = {
> {"frame-size", required_argument, 0, 'f'},
> {"no-need-wakeup", no_argument, 0, 'm'},
> {"unaligned", no_argument, 0, 'u'},
> + {"shared-umem", no_argument, 0, 'M'},
> {0, 0, 0, 0}
> };
>
> @@ -386,6 +388,7 @@ static void usage(const char *prog)
> " -m, --no-need-wakeup Turn off use of driver need wakeup flag.\n"
> " -f, --frame-size=n Set the frame size (must be a power of two in aligned mode, default is %d).\n"
> " -u, --unaligned Enable unaligned chunk placement\n"
> + " -M, --shared-umem Enable XDP_SHARED_UMEM\n"
> "\n";
> fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE);
> exit(EXIT_FAILURE);
> @@ -398,7 +401,7 @@ static void parse_command_line(int argc, char **argv)
> opterr = 0;
>
> for (;;) {
> - c = getopt_long(argc, argv, "Frtli:q:psSNn:czf:mu",
> + c = getopt_long(argc, argv, "Frtli:q:psSNn:czf:muM",
> long_options, &option_index);
> if (c == -1)
> break;
> @@ -448,11 +451,14 @@ static void parse_command_line(int argc, char **argv)
> break;
> case 'f':
> opt_xsk_frame_size = atoi(optarg);
> + break;
> case 'm':
> opt_need_wakeup = false;
> opt_xdp_bind_flags &= ~XDP_USE_NEED_WAKEUP;
> break;
> -
> + case 'M':
> + opt_num_xsks = MAX_SOCKS;
> + break;
> default:
> usage(basename(argv[0]));
> }
> @@ -586,11 +592,9 @@ static void rx_drop(struct xsk_socket_info *xsk, struct pollfd *fds)
>
> static void rx_drop_all(void)
> {
> - struct pollfd fds[MAX_SOCKS + 1];
> + struct pollfd fds[MAX_SOCKS] = {};
> int i, ret;
>
> - memset(fds, 0, sizeof(fds));
> -
> for (i = 0; i < num_socks; i++) {
> fds[i].fd = xsk_socket__fd(xsks[i]->xsk);
> fds[i].events = POLLIN;
> @@ -633,11 +637,10 @@ static void tx_only(struct xsk_socket_info *xsk, u32 frame_nb)
>
> static void tx_only_all(void)
> {
> - struct pollfd fds[MAX_SOCKS];
> + struct pollfd fds[MAX_SOCKS] = {};
> u32 frame_nb[MAX_SOCKS] = {};
> int i, ret;
>
> - memset(fds, 0, sizeof(fds));
> for (i = 0; i < num_socks; i++) {
> fds[0].fd = xsk_socket__fd(xsks[i]->xsk);
> fds[0].events = POLLOUT;
> @@ -706,11 +709,9 @@ static void l2fwd(struct xsk_socket_info *xsk, struct pollfd *fds)
>
> static void l2fwd_all(void)
> {
> - struct pollfd fds[MAX_SOCKS];
> + struct pollfd fds[MAX_SOCKS] = {};
> int i, ret;
>
> - memset(fds, 0, sizeof(fds));
> -
> for (i = 0; i < num_socks; i++) {
> fds[i].fd = xsk_socket__fd(xsks[i]->xsk);
> fds[i].events = POLLOUT | POLLIN;
> @@ -728,13 +729,65 @@ static void l2fwd_all(void)
> }
> }
>
> +static void load_xdp_program(char **argv, struct bpf_object **obj)
> +{
> + struct bpf_prog_load_attr prog_load_attr = {
> + .prog_type = BPF_PROG_TYPE_XDP,
> + };
> + char xdp_filename[256];
> + int prog_fd;
> +
> + snprintf(xdp_filename, sizeof(xdp_filename), "%s_kern.o", argv[0]);
> + prog_load_attr.file = xdp_filename;
> +
> + if (bpf_prog_load_xattr(&prog_load_attr, obj, &prog_fd))
> + exit(EXIT_FAILURE);
> + if (prog_fd < 0) {
> + fprintf(stderr, "ERROR: no program found: %s\n",
> + strerror(prog_fd));
> + exit(EXIT_FAILURE);
> + }
> +
> + if (bpf_set_link_xdp_fd(opt_ifindex, prog_fd, opt_xdp_flags) < 0) {
> + fprintf(stderr, "ERROR: link set xdp fd failed\n");
> + exit(EXIT_FAILURE);
> + }
> +}
> +
> +static void enter_xsks_into_map(struct bpf_object *obj)
> +{
> + struct bpf_map *map;
> + int i, xsks_map;
> +
> + map = bpf_object__find_map_by_name(obj, "xsks_map");
> + xsks_map = bpf_map__fd(map);
> + if (xsks_map < 0) {
> + fprintf(stderr, "ERROR: no xsks map found: %s\n",
> + strerror(xsks_map));
> + exit(EXIT_FAILURE);
> + }
> +
> + for (i = 0; i < num_socks; i++) {
> + int fd = xsk_socket__fd(xsks[i]->xsk);
> + int key, ret;
> +
> + key = i;
> + ret = bpf_map_update_elem(xsks_map, &key, &fd, 0);
> + if (ret) {
> + fprintf(stderr, "ERROR: bpf_map_update_elem %d\n", i);
> + exit(EXIT_FAILURE);
> + }
> + }
> +}
> +
> int main(int argc, char **argv)
> {
> struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
> struct xsk_umem_info *umem;
> + struct bpf_object *obj;
> pthread_t pt;
> + int i, ret;
> void *bufs;
> - int ret;
>
> parse_command_line(argc, argv);
>
> @@ -744,6 +797,9 @@ int main(int argc, char **argv)
> exit(EXIT_FAILURE);
> }
>
> + if (opt_num_xsks > 1)
> + load_xdp_program(argv, &obj);
> +
> /* Reserve memory for the umem. Use hugepages if unaligned chunk mode */
> bufs = mmap(NULL, NUM_FRAMES * opt_xsk_frame_size,
> PROT_READ | PROT_WRITE,
> @@ -752,16 +808,17 @@ int main(int argc, char **argv)
> printf("ERROR: mmap failed\n");
> exit(EXIT_FAILURE);
> }
> - /* Create sockets... */
> +
> + /* Create sockets... */
> umem = xsk_configure_umem(bufs, NUM_FRAMES * opt_xsk_frame_size);
> - xsks[num_socks++] = xsk_configure_socket(umem);
> + for (i = 0; i < opt_num_xsks; i++)
> + xsks[num_socks++] = xsk_configure_socket(umem);
>
> - if (opt_bench == BENCH_TXONLY) {
> - int i;
> + for (i = 0; i < NUM_FRAMES; i++)
> + gen_eth_frame(umem, i * opt_xsk_frame_size);
>
> - for (i = 0; i < NUM_FRAMES; i++)
> - (void)gen_eth_frame(umem, i * opt_xsk_frame_size);
> - }
> + if (opt_num_xsks > 1 && opt_bench != BENCH_TXONLY)
> + enter_xsks_into_map(obj);
>
> signal(SIGINT, int_exit);
> signal(SIGTERM, int_exit);
> --
> 2.7.4
>
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