A Sample of using socket cookie and uid for traffic monitoring (51570a5a) · Commits · 戴 / test

samples/bpf/Makefile

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Original line number	Diff line number	Diff line
		@@ -35,6 +35,7 @@ hostprogs-y += tc_l2_redirect
		hostprogs-y += lwt_len_hist
		hostprogs-y += xdp_tx_iptunnel
		hostprogs-y += test_map_in_map
		hostprogs-y += per_socket_stats_example

		# Libbpf dependencies
		LIBBPF := ../../tools/lib/bpf/bpf.o
		@@ -74,6 +75,7 @@ tc_l2_redirect-objs := bpf_load.o $(LIBBPF) tc_l2_redirect_user.o
		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

		# Tell kbuild to always build the programs
		always := $(hostprogs-y)
		@@ -108,6 +110,7 @@ always += sampleip_kern.o
		always += lwt_len_hist_kern.o
		always += xdp_tx_iptunnel_kern.o
		always += test_map_in_map_kern.o
		always += cookie_uid_helper_example.o

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

samples/bpf/cookie_uid_helper_example.c

0 → 100644

+217 −0

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		/* This test is a demo of using get_socket_uid and get_socket_cookie
		* helper function to do per socket based network traffic monitoring.
		* It requires iptables version higher then 1.6.1. to load pinned eBPF
		* program into the xt_bpf match.
		*
		* TEST:
		* ./run_cookie_uid_helper_example.sh
		* Then generate some traffic in variate ways. ping 0 -c 10 would work
		* but the cookie and uid in this case could both be 0. A sample output
		* with some traffic generated by web browser is shown below:
		*
		* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
		* cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 286
		* cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 1726
		* cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
		* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
		* cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
		* cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 712
		* cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 70
		*
		* Clean up: if using shell script, the script file will delete the iptables
		* rule and unmount the bpf program when exit. Else the iptables rule need
		* to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.
		*/

		#define _GNU_SOURCE

		#define offsetof(type, member) __builtin_offsetof(type, member)
		#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))

		#include <arpa/inet.h>
		#include <errno.h>
		#include <error.h>
		#include <limits.h>
		#include <linux/bpf.h>
		#include <linux/if_ether.h>
		#include <stdbool.h>
		#include <stdint.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <sys/socket.h>
		#include <sys/stat.h>
		#include <sys/types.h>
		#include <unistd.h>
		#include <bpf/bpf.h>
		#include "libbpf.h"

		struct stats {
		uint32_t uid;
		uint64_t packets;
		uint64_t bytes;
		};

		static int map_fd, prog_fd;

		static void maps_create(void)
		{
		map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(uint32_t),
		sizeof(struct stats), 100, 0);
		if (map_fd < 0)
		error(1, errno, "map create failed!\n");
		}

		static void prog_load(void)
		{
		static char log_buf[1 << 16];

		struct bpf_insn prog[] = {
		/*
		* Save sk_buff for future usage. value stored in R6 to R10 will
		* not be reset after a bpf helper function call.
		*/
		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
		/*
		* pc1: BPF_FUNC_get_socket_cookie takes one parameter,
		* R1: sk_buff
		*/
		BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
		BPF_FUNC_get_socket_cookie),
		/* pc2-4: save &socketCookie to r7 for future usage*/
		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
		BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
		/*
		* pc5-8: set up the registers for BPF_FUNC_map_lookup_elem,
		* it takes two parameters (R1: map_fd, R2: &socket_cookie)
		*/
		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
		BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
		BPF_FUNC_map_lookup_elem),
		/*
		* pc9. if r0 != 0x0, go to pc+14, since we have the cookie
		* stored already
		* Otherwise do pc10-22 to setup a new data entry.
		*/
		BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 14),
		BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
		BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
		BPF_FUNC_get_socket_uid),
		/*
		* Place a struct stats in the R10 stack and sequentially
		* place the member value into the memory. Packets value
		* is set by directly place a IMM value 1 into the stack.
		*/
		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0,
		-32 + offsetof(struct stats, uid)),
		BPF_ST_MEM(BPF_DW, BPF_REG_10,
		-32 + offsetof(struct stats, packets), 1),
		/*
		* __sk_buff is a special struct used for eBPF program to
		* directly access some sk_buff field.
		*/
		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
		offsetof(struct __sk_buff, len)),
		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1,
		-32 + offsetof(struct stats, bytes)),
		/*
		* add new map entry using BPF_FUNC_map_update_elem, it takes
		* 4 parameters (R1: map_fd, R2: &socket_cookie, R3: &stats,
		* R4: flags)
		*/
		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
		BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32),
		BPF_MOV64_IMM(BPF_REG_4, 0),
		BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
		BPF_FUNC_map_update_elem),
		BPF_JMP_IMM(BPF_JA, 0, 0, 5),
		/*
		* pc24-30 update the packet info to a exist data entry, it can
		* be done by directly write to pointers instead of using
		* BPF_FUNC_map_update_elem helper function
		*/
		BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
		BPF_MOV64_IMM(BPF_REG_1, 1),
		BPF_STX_XADD(BPF_DW, BPF_REG_9, BPF_REG_1,
		offsetof(struct stats, packets)),
		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
		offsetof(struct __sk_buff, len)),
		BPF_STX_XADD(BPF_DW, BPF_REG_9, BPF_REG_1,
		offsetof(struct stats, bytes)),
		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
		offsetof(struct __sk_buff, len)),
		BPF_EXIT_INSN(),
		};
		prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog,
		ARRAY_SIZE(prog), "GPL", 0,
		log_buf, sizeof(log_buf));
		if (prog_fd < 0)
		error(1, errno, "failed to load prog\n%s\n", log_buf);
		}

		static void prog_attach_iptables(char *file)
		{
		int ret;
		char rules[100];

		if (bpf_obj_pin(prog_fd, file))
		error(1, errno, "bpf_obj_pin");
		if (strlen(file) > 50) {
		printf("file path too long: %s\n", file);
		exit(1);
		}
		sprintf(rules, "iptables -A INPUT -m bpf --object-pinned %s -j ACCEPT",
		file);
		ret = system(rules);
		if (ret < 0) {
		printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
		exit(1);
		}
		}

		static void print_table(void)
		{
		struct stats curEntry;
		uint32_t curN = UINT32_MAX;
		uint32_t nextN, res;

		while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {
		curN = nextN;
		res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);
		if (res < 0) {
		error(1, errno, "fail to get entry value of Key: %u\n",
		curN);
		} else {
		printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"
		" Bytes Count: %lu\n", curN, curEntry.uid,
		curEntry.packets, curEntry.bytes);
		}
		}
		}

		int main(int argc, char *argv[])
		{
		if (argc > 2) {
		printf("Too many argument provided\n");
		return 1;
		} else if (argc < 2) {
		printf("Usage: %s bpfObjName\n", argv[0]);
		return 1;
		}

		maps_create();
		prog_load();
		prog_attach_iptables(argv[1]);

		while (true) {
		print_table();
		printf("\n");
		sleep(1);
		};

		return 0;
		}

samples/bpf/libbpf.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -135,6 +135,16 @@ struct bpf_insn;
		.off = OFF, \
		.imm = 0 })

		/* Atomic memory add, (uint )(dst_reg + off16) += src_reg */

		#define BPF_STX_XADD(SIZE, DST, SRC, OFF) \
		((struct bpf_insn) { \
		.code = BPF_STX \| BPF_SIZE(SIZE) \| BPF_XADD, \
		.dst_reg = DST, \
		.src_reg = SRC, \
		.off = OFF, \
		.imm = 0 })

		/* Memory store, (uint ) (dst_reg + off16) = imm32 */

		#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \

samples/bpf/run_cookie_uid_helper_example.sh

0 → 100644

+14 −0

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		#!/bin/bash
		local_dir="$(pwd)"
		root_dir=$local_dir/../..
		mnt_dir=$(mktemp -d --tmp)

		on_exit() {
		iptables -D INPUT -m bpf --object-pinned ${mnt_dir}/bpf_prog -j ACCEPT
		umount ${mnt_dir}
		rm -r ${mnt_dir}
		}

		trap on_exit EXIT
		mount -t bpf bpf ${mnt_dir}
		./per_socket_stats_example ${mnt_dir}/bpf_prog

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