A Sample of using socket cookie and uid for traffic monitoring

Add a sample program to demostrate the possible usage of
get_socket_cookie and get_socket_uid helper function. The program will
store bytes and packets counting of in/out traffic monitored by iptables
and store the stats in a bpf map in per socket base. The owner uid of
the socket will be stored as part of the data entry. A shell script for
running the program is also included.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Chenbo Feng <fengc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chenbo Feng 2017-03-22 17:27:36 -07:00 committed by David S. Miller
parent 6acc5c2910
commit 51570a5ab2
4 changed files with 244 additions and 0 deletions

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@ -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/

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@ -0,0 +1,217 @@
/* 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;
}

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@ -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) \

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@ -0,0 +1,14 @@
#!/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