bpf: add sample for xdp forwarding and rewrite (764cbcce) · Commits · 戴 / test

samples/bpf/Makefile

+5 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@ hostprogs-y += map_perf_test
		hostprogs-y += test_overhead
		hostprogs-y += test_cgrp2_array_pin
		hostprogs-y += xdp1
		hostprogs-y += xdp2

		test_verifier-objs := test_verifier.o libbpf.o
		test_maps-objs := test_maps.o libbpf.o
		@@ -44,6 +45,8 @@ map_perf_test-objs := bpf_load.o libbpf.o map_perf_test_user.o
		test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o
		test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o
		xdp1-objs := bpf_load.o libbpf.o xdp1_user.o
		# reuse xdp1 source intentionally
		xdp2-objs := bpf_load.o libbpf.o xdp1_user.o

		# Tell kbuild to always build the programs
		always := $(hostprogs-y)
		@@ -67,6 +70,7 @@ always += test_overhead_kprobe_kern.o
		always += parse_varlen.o parse_simple.o parse_ldabs.o
		always += test_cgrp2_tc_kern.o
		always += xdp1_kern.o
		always += xdp2_kern.o

		HOSTCFLAGS += -I$(objtree)/usr/include

		@@ -88,6 +92,7 @@ HOSTLOADLIBES_spintest += -lelf
		HOSTLOADLIBES_map_perf_test += -lelf -lrt
		HOSTLOADLIBES_test_overhead += -lelf -lrt
		HOSTLOADLIBES_xdp1 += -lelf
		HOSTLOADLIBES_xdp2 += -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/xdp2_kern.c

0 → 100644

+114 −0

Original line number	Diff line number	Diff line
		/* Copyright (c) 2016 PLUMgrid
		*
		* 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.
		*/
		#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") dropcnt = {
		.type = BPF_MAP_TYPE_PERCPU_ARRAY,
		.key_size = sizeof(u32),
		.value_size = sizeof(long),
		.max_entries = 256,
		};

		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];
		}

		static int parse_ipv4(void data, u64 nh_off, void data_end)
		{
		struct iphdr *iph = data + nh_off;

		if (iph + 1 > data_end)
		return 0;
		return iph->protocol;
		}

		static int parse_ipv6(void data, u64 nh_off, void data_end)
		{
		struct ipv6hdr *ip6h = data + nh_off;

		if (ip6h + 1 > data_end)
		return 0;
		return ip6h->nexthdr;
		}

		SEC("xdp1")
		int xdp_prog1(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;
		long *value;
		u16 h_proto;
		u64 nh_off;
		u32 index;

		nh_off = sizeof(*eth);
		if (data + nh_off > data_end)
		return rc;

		h_proto = eth->h_proto;

		if (h_proto == htons(ETH_P_8021Q) \|\| h_proto == htons(ETH_P_8021AD)) {
		struct vlan_hdr *vhdr;

		vhdr = data + nh_off;
		nh_off += sizeof(struct vlan_hdr);
		if (data + nh_off > data_end)
		return rc;
		h_proto = vhdr->h_vlan_encapsulated_proto;
		}
		if (h_proto == htons(ETH_P_8021Q) \|\| h_proto == htons(ETH_P_8021AD)) {
		struct vlan_hdr *vhdr;

		vhdr = data + nh_off;
		nh_off += sizeof(struct vlan_hdr);
		if (data + nh_off > data_end)
		return rc;
		h_proto = vhdr->h_vlan_encapsulated_proto;
		}

		if (h_proto == htons(ETH_P_IP))
		index = parse_ipv4(data, nh_off, data_end);
		else if (h_proto == htons(ETH_P_IPV6))
		index = parse_ipv6(data, nh_off, data_end);
		else
		index = 0;

		value = bpf_map_lookup_elem(&dropcnt, &index);
		if (value)
		*value += 1;

		if (index == 17) {
		swap_src_dst_mac(data);
		rc = XDP_TX;
		}

		return rc;
		}

		char _license[] SEC("license") = "GPL";

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