xdp: sample program for new bpf_redirect helper

This implements a sample program for testing bpf_redirect. It reports
the number of packets redirected per second and as input takes the
ifindex of the device to run the xdp program on and the ifindex of the
interface to redirect packets to.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Tested-by: Andy Gospodarek <andy@greyhouse.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Fastabend 2017-07-17 09:27:28 -07:00 committed by David S. Miller
parent 814abfabef
commit 832622e6bd
3 changed files with 187 additions and 0 deletions

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@ -37,6 +37,7 @@ hostprogs-y += xdp_tx_iptunnel
hostprogs-y += test_map_in_map hostprogs-y += test_map_in_map
hostprogs-y += per_socket_stats_example hostprogs-y += per_socket_stats_example
hostprogs-y += load_sock_ops hostprogs-y += load_sock_ops
hostprogs-y += xdp_redirect
# Libbpf dependencies # Libbpf dependencies
LIBBPF := ../../tools/lib/bpf/bpf.o LIBBPF := ../../tools/lib/bpf/bpf.o
@ -78,6 +79,7 @@ lwt_len_hist-objs := bpf_load.o $(LIBBPF) lwt_len_hist_user.o
xdp_tx_iptunnel-objs := bpf_load.o $(LIBBPF) xdp_tx_iptunnel_user.o xdp_tx_iptunnel-objs := bpf_load.o $(LIBBPF) xdp_tx_iptunnel_user.o
test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o
per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o
xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
# Tell kbuild to always build the programs # Tell kbuild to always build the programs
always := $(hostprogs-y) always := $(hostprogs-y)
@ -119,6 +121,7 @@ always += tcp_bufs_kern.o
always += tcp_cong_kern.o always += tcp_cong_kern.o
always += tcp_iw_kern.o always += tcp_iw_kern.o
always += tcp_clamp_kern.o always += tcp_clamp_kern.o
always += xdp_redirect_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(objtree)/usr/include
HOSTCFLAGS += -I$(srctree)/tools/lib/ HOSTCFLAGS += -I$(srctree)/tools/lib/
@ -155,6 +158,7 @@ HOSTLOADLIBES_tc_l2_redirect += -l elf
HOSTLOADLIBES_lwt_len_hist += -l elf HOSTLOADLIBES_lwt_len_hist += -l elf
HOSTLOADLIBES_xdp_tx_iptunnel += -lelf HOSTLOADLIBES_xdp_tx_iptunnel += -lelf
HOSTLOADLIBES_test_map_in_map += -lelf HOSTLOADLIBES_test_map_in_map += -lelf
HOSTLOADLIBES_xdp_redirect += -lelf
# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang # make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

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@ -0,0 +1,81 @@
/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that 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.
*/
#define KBUILD_MODNAME "foo"
#include <uapi/linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_vlan.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") tx_port = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 1,
};
struct bpf_map_def SEC("maps") rxcnt = {
.type = BPF_MAP_TYPE_PERCPU_ARRAY,
.key_size = sizeof(u32),
.value_size = sizeof(long),
.max_entries = 1,
};
static void swap_src_dst_mac(void *data)
{
unsigned short *p = data;
unsigned short dst[3];
dst[0] = p[0];
dst[1] = p[1];
dst[2] = p[2];
p[0] = p[3];
p[1] = p[4];
p[2] = p[5];
p[3] = dst[0];
p[4] = dst[1];
p[5] = dst[2];
}
SEC("xdp_redirect")
int xdp_redirect_prog(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
int rc = XDP_DROP;
int *ifindex, port = 0;
long *value;
u32 key = 0;
u64 nh_off;
nh_off = sizeof(*eth);
if (data + nh_off > data_end)
return rc;
ifindex = bpf_map_lookup_elem(&tx_port, &port);
if (!ifindex)
return rc;
value = bpf_map_lookup_elem(&rxcnt, &key);
if (value)
*value += 1;
swap_src_dst_mac(data);
return bpf_redirect(*ifindex, 0);
}
char _license[] SEC("license") = "GPL";

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@ -0,0 +1,102 @@
/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that 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 <linux/bpf.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "bpf_load.h"
#include "bpf_util.h"
#include "libbpf.h"
static int ifindex_in;
static int ifindex_out;
static void int_exit(int sig)
{
set_link_xdp_fd(ifindex_in, -1, 0);
exit(0);
}
/* simple per-protocol drop counter
*/
static void poll_stats(int interval, int ifindex)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
__u64 values[nr_cpus], prev[nr_cpus];
memset(prev, 0, sizeof(prev));
while (1) {
__u64 sum = 0;
__u32 key = 0;
int i;
sleep(interval);
assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
for (i = 0; i < nr_cpus; i++)
sum += (values[i] - prev[i]);
if (sum)
printf("ifindex %i: %10llu pkt/s\n",
ifindex, sum / interval);
memcpy(prev, values, sizeof(values));
}
}
int main(int ac, char **argv)
{
char filename[256];
int ret, key = 0;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (ac != 3) {
printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
return 1;
}
ifindex_in = strtoul(argv[1], NULL, 0);
ifindex_out = strtoul(argv[2], NULL, 0);
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
if (!prog_fd[0]) {
printf("load_bpf_file: %s\n", strerror(errno));
return 1;
}
signal(SIGINT, int_exit);
if (set_link_xdp_fd(ifindex_in, prog_fd[0], 0) < 0) {
printf("link set xdp fd failed\n");
return 1;
}
/* bpf redirect port */
ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0);
if (ret) {
perror("bpf_update_elem");
goto out;
}
poll_stats(2, ifindex_out);
out:
return 0;
}