Add sample for adding simple drop program to link (86af8b41) · Commits · 戴 / test

samples/bpf/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@ hostprogs-y += spintest
		hostprogs-y += map_perf_test
		hostprogs-y += test_overhead
		hostprogs-y += test_cgrp2_array_pin
		hostprogs-y += xdp1

		test_verifier-objs := test_verifier.o libbpf.o
		test_maps-objs := test_maps.o libbpf.o
		@@ -42,6 +43,7 @@ spintest-objs := bpf_load.o libbpf.o spintest_user.o
		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

		# Tell kbuild to always build the programs
		always := $(hostprogs-y)
		@@ -64,6 +66,7 @@ always += test_overhead_tp_kern.o
		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

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

		@@ -84,6 +87,7 @@ HOSTLOADLIBES_offwaketime += -lelf
		HOSTLOADLIBES_spintest += -lelf
		HOSTLOADLIBES_map_perf_test += -lelf -lrt
		HOSTLOADLIBES_test_overhead += -lelf -lrt
		HOSTLOADLIBES_xdp1 += -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/bpf_load.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -50,6 +50,7 @@ static int load_and_attach(const char event, struct bpf_insn prog, int size)
		bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
		bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
		bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
		bool is_xdp = strncmp(event, "xdp", 3) == 0;
		enum bpf_prog_type prog_type;
		char buf[256];
		int fd, efd, err, id;
		@@ -66,6 +67,8 @@ static int load_and_attach(const char event, struct bpf_insn prog, int size)
		prog_type = BPF_PROG_TYPE_KPROBE;
		} else if (is_tracepoint) {
		prog_type = BPF_PROG_TYPE_TRACEPOINT;
		} else if (is_xdp) {
		prog_type = BPF_PROG_TYPE_XDP;
		} else {
		printf("Unknown event '%s'\n", event);
		return -1;
		@@ -79,6 +82,9 @@ static int load_and_attach(const char event, struct bpf_insn prog, int size)

		prog_fd[prog_cnt++] = fd;

		if (is_xdp)
		return 0;

		if (is_socket) {
		event += 6;
		if (*event != '/')
		@@ -319,6 +325,7 @@ int load_bpf_file(char *path)
		if (memcmp(shname_prog, "kprobe/", 7) == 0 \|\|
		memcmp(shname_prog, "kretprobe/", 10) == 0 \|\|
		memcmp(shname_prog, "tracepoint/", 11) == 0 \|\|
		memcmp(shname_prog, "xdp", 3) == 0 \|\|
		memcmp(shname_prog, "socket", 6) == 0)
		load_and_attach(shname_prog, insns, data_prog->d_size);
		}
		@@ -336,6 +343,7 @@ int load_bpf_file(char *path)
		if (memcmp(shname, "kprobe/", 7) == 0 \|\|
		memcmp(shname, "kretprobe/", 10) == 0 \|\|
		memcmp(shname, "tracepoint/", 11) == 0 \|\|
		memcmp(shname, "xdp", 3) == 0 \|\|
		memcmp(shname, "socket", 6) == 0)
		load_and_attach(shname, data->d_buf, data->d_size);
		}

samples/bpf/xdp1_kern.c

0 → 100644

+93 −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 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;

		return rc;
		}

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

samples/bpf/xdp1_user.c

0 → 100644

+181 −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.
		*/
		#include <linux/bpf.h>
		#include <linux/netlink.h>
		#include <linux/rtnetlink.h>
		#include <assert.h>
		#include <errno.h>
		#include <signal.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <sys/socket.h>
		#include <unistd.h>
		#include "bpf_load.h"
		#include "libbpf.h"

		static int set_link_xdp_fd(int ifindex, int fd)
		{
		struct sockaddr_nl sa;
		int sock, seq = 0, len, ret = -1;
		char buf[4096];
		struct nlattr nla, nla_xdp;
		struct {
		struct nlmsghdr nh;
		struct ifinfomsg ifinfo;
		char attrbuf[64];
		} req;
		struct nlmsghdr *nh;
		struct nlmsgerr *err;

		memset(&sa, 0, sizeof(sa));
		sa.nl_family = AF_NETLINK;

		sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
		if (sock < 0) {
		printf("open netlink socket: %s\n", strerror(errno));
		return -1;
		}

		if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
		printf("bind to netlink: %s\n", strerror(errno));
		goto cleanup;
		}

		memset(&req, 0, sizeof(req));
		req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
		req.nh.nlmsg_flags = NLM_F_REQUEST \| NLM_F_ACK;
		req.nh.nlmsg_type = RTM_SETLINK;
		req.nh.nlmsg_pid = 0;
		req.nh.nlmsg_seq = ++seq;
		req.ifinfo.ifi_family = AF_UNSPEC;
		req.ifinfo.ifi_index = ifindex;
		nla = (struct nlattr )(((char )&req)
		+ NLMSG_ALIGN(req.nh.nlmsg_len));
		nla->nla_type = NLA_F_NESTED \| 43/IFLA_XDP/;

		nla_xdp = (struct nlattr )((char )nla + NLA_HDRLEN);
		nla_xdp->nla_type = 1/IFLA_XDP_FD/;
		nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
		memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
		nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len;

		req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);

		if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
		printf("send to netlink: %s\n", strerror(errno));
		goto cleanup;
		}

		len = recv(sock, buf, sizeof(buf), 0);
		if (len < 0) {
		printf("recv from netlink: %s\n", strerror(errno));
		goto cleanup;
		}

		for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
		nh = NLMSG_NEXT(nh, len)) {
		if (nh->nlmsg_pid != getpid()) {
		printf("Wrong pid %d, expected %d\n",
		nh->nlmsg_pid, getpid());
		goto cleanup;
		}
		if (nh->nlmsg_seq != seq) {
		printf("Wrong seq %d, expected %d\n",
		nh->nlmsg_seq, seq);
		goto cleanup;
		}
		switch (nh->nlmsg_type) {
		case NLMSG_ERROR:
		err = (struct nlmsgerr *)NLMSG_DATA(nh);
		if (!err->error)
		continue;
		printf("nlmsg error %s\n", strerror(-err->error));
		goto cleanup;
		case NLMSG_DONE:
		break;
		}
		}

		ret = 0;

		cleanup:
		close(sock);
		return ret;
		}

		static int ifindex;

		static void int_exit(int sig)
		{
		set_link_xdp_fd(ifindex, -1);
		exit(0);
		}

		/* simple per-protocol drop counter
		*/
		static void poll_stats(int interval)
		{
		unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
		const unsigned int nr_keys = 256;
		__u64 values[nr_cpus], prev[nr_keys][nr_cpus];
		__u32 key;
		int i;

		memset(prev, 0, sizeof(prev));

		while (1) {
		sleep(interval);

		for (key = 0; key < nr_keys; key++) {
		__u64 sum = 0;

		assert(bpf_lookup_elem(map_fd[0], &key, values) == 0);
		for (i = 0; i < nr_cpus; i++)
		sum += (values[i] - prev[key][i]);
		if (sum)
		printf("proto %u: %10llu pkt/s\n",
		key, sum / interval);
		memcpy(prev[key], values, sizeof(values));
		}
		}
		}

		int main(int ac, char **argv)
		{
		char filename[256];

		snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

		if (ac != 2) {
		printf("usage: %s IFINDEX\n", argv[0]);
		return 1;
		}

		ifindex = strtoul(argv[1], 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, prog_fd[0]) < 0) {
		printf("link set xdp fd failed\n");
		return 1;
		}

		poll_stats(2);

		return 0;
		}

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