xdp: sample program for new bpf_redirect helper (832622e6) · Commits · 戴 / test

samples/bpf/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@ hostprogs-y += xdp_tx_iptunnel
		hostprogs-y += test_map_in_map
		hostprogs-y += per_socket_stats_example
		hostprogs-y += load_sock_ops
		hostprogs-y += xdp_redirect

		# Libbpf dependencies
		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
		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
		xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o

		# Tell kbuild to always build the programs
		always := $(hostprogs-y)
		@@ -119,6 +121,7 @@ always += tcp_bufs_kern.o
		always += tcp_cong_kern.o
		always += tcp_iw_kern.o
		always += tcp_clamp_kern.o
		always += xdp_redirect_kern.o

		HOSTCFLAGS += -I$(objtree)/usr/include
		HOSTCFLAGS += -I$(srctree)/tools/lib/
		@@ -155,6 +158,7 @@ HOSTLOADLIBES_tc_l2_redirect += -l elf
		HOSTLOADLIBES_lwt_len_hist += -l elf
		HOSTLOADLIBES_xdp_tx_iptunnel += -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:
		# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

samples/bpf/xdp_redirect_kern.c

0 → 100644

+81 −0

Original line number	Diff line number	Diff line
		/* 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";

samples/bpf/xdp_redirect_user.c

0 → 100644

+102 −0

Original line number	Diff line number	Diff line
		/* 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;
		}

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