324 lines
9.2 KiB
C
324 lines
9.2 KiB
C
/* This test is a demo of using get_socket_uid and get_socket_cookie
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* helper function to do per socket based network traffic monitoring.
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* It requires iptables version higher then 1.6.1. to load pinned eBPF
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* program into the xt_bpf match.
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*
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* TEST:
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* ./run_cookie_uid_helper_example.sh -option
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* option:
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* -t: do traffic monitoring test, the program will continuously
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* print out network traffic happens after program started A sample
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* output is shown below:
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*
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* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
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* cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 286
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* cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 1726
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* cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
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* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
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* cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
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* cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 712
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* cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 70
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*
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* -s: do getsockopt SO_COOKIE test, the program will set up a pair of
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* UDP sockets and send packets between them. And read out the traffic data
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* directly from the ebpf map based on the socket cookie.
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*
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* Clean up: if using shell script, the script file will delete the iptables
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* rule and unmount the bpf program when exit. Else the iptables rule need
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* to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.
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*/
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#define _GNU_SOURCE
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#define offsetof(type, member) __builtin_offsetof(type, member)
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
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#include <arpa/inet.h>
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#include <errno.h>
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#include <error.h>
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#include <limits.h>
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#include <linux/bpf.h>
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#include <linux/if_ether.h>
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#include <net/if.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <bpf/bpf.h>
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#include "libbpf.h"
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#define PORT 8888
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struct stats {
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uint32_t uid;
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uint64_t packets;
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uint64_t bytes;
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};
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static int map_fd, prog_fd;
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static bool test_finish;
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static void maps_create(void)
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{
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map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(uint32_t),
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sizeof(struct stats), 100, 0);
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if (map_fd < 0)
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error(1, errno, "map create failed!\n");
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}
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static void prog_load(void)
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{
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static char log_buf[1 << 16];
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struct bpf_insn prog[] = {
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/*
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* Save sk_buff for future usage. value stored in R6 to R10 will
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* not be reset after a bpf helper function call.
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*/
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BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
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/*
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* pc1: BPF_FUNC_get_socket_cookie takes one parameter,
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* R1: sk_buff
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*/
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_get_socket_cookie),
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/* pc2-4: save &socketCookie to r7 for future usage*/
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BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
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BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
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/*
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* pc5-8: set up the registers for BPF_FUNC_map_lookup_elem,
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* it takes two parameters (R1: map_fd, R2: &socket_cookie)
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*/
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BPF_LD_MAP_FD(BPF_REG_1, map_fd),
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BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_map_lookup_elem),
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/*
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* pc9. if r0 != 0x0, go to pc+14, since we have the cookie
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* stored already
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* Otherwise do pc10-22 to setup a new data entry.
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*/
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BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 14),
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BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_get_socket_uid),
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/*
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* Place a struct stats in the R10 stack and sequentially
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* place the member value into the memory. Packets value
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* is set by directly place a IMM value 1 into the stack.
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*/
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BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0,
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-32 + (__s16)offsetof(struct stats, uid)),
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BPF_ST_MEM(BPF_DW, BPF_REG_10,
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-32 + (__s16)offsetof(struct stats, packets), 1),
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/*
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* __sk_buff is a special struct used for eBPF program to
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* directly access some sk_buff field.
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*/
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BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
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offsetof(struct __sk_buff, len)),
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BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1,
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-32 + (__s16)offsetof(struct stats, bytes)),
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/*
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* add new map entry using BPF_FUNC_map_update_elem, it takes
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* 4 parameters (R1: map_fd, R2: &socket_cookie, R3: &stats,
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* R4: flags)
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*/
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BPF_LD_MAP_FD(BPF_REG_1, map_fd),
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BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
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BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32),
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BPF_MOV64_IMM(BPF_REG_4, 0),
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_map_update_elem),
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BPF_JMP_IMM(BPF_JA, 0, 0, 5),
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/*
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* pc24-30 update the packet info to a exist data entry, it can
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* be done by directly write to pointers instead of using
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* BPF_FUNC_map_update_elem helper function
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*/
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BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
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BPF_MOV64_IMM(BPF_REG_1, 1),
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BPF_STX_XADD(BPF_DW, BPF_REG_9, BPF_REG_1,
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offsetof(struct stats, packets)),
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BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
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offsetof(struct __sk_buff, len)),
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BPF_STX_XADD(BPF_DW, BPF_REG_9, BPF_REG_1,
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offsetof(struct stats, bytes)),
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
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offsetof(struct __sk_buff, len)),
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BPF_EXIT_INSN(),
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};
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prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog,
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ARRAY_SIZE(prog), "GPL", 0,
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log_buf, sizeof(log_buf));
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if (prog_fd < 0)
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error(1, errno, "failed to load prog\n%s\n", log_buf);
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}
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static void prog_attach_iptables(char *file)
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{
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int ret;
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char rules[100];
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if (bpf_obj_pin(prog_fd, file))
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error(1, errno, "bpf_obj_pin");
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if (strlen(file) > 50) {
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printf("file path too long: %s\n", file);
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exit(1);
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}
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sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
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file);
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ret = system(rules);
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if (ret < 0) {
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printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
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exit(1);
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}
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}
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static void print_table(void)
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{
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struct stats curEntry;
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uint32_t curN = UINT32_MAX;
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uint32_t nextN;
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int res;
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while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {
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curN = nextN;
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res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);
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if (res < 0) {
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error(1, errno, "fail to get entry value of Key: %u\n",
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curN);
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} else {
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printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"
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" Bytes Count: %lu\n", curN, curEntry.uid,
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curEntry.packets, curEntry.bytes);
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}
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}
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}
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static void udp_client(void)
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{
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struct sockaddr_in si_other = {0};
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struct sockaddr_in si_me = {0};
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struct stats dataEntry;
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int s_rcv, s_send, i, recv_len;
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char message = 'a';
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char buf;
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uint64_t cookie;
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int res;
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socklen_t cookie_len = sizeof(cookie);
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socklen_t slen = sizeof(si_other);
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s_rcv = socket(PF_INET, SOCK_DGRAM, 0);
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if (s_rcv < 0)
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error(1, errno, "rcv socket creat failed!\n");
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si_other.sin_family = AF_INET;
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si_other.sin_port = htons(PORT);
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if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0)
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error(1, errno, "inet_aton\n");
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if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1)
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error(1, errno, "bind\n");
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s_send = socket(PF_INET, SOCK_DGRAM, 0);
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if (s_send < 0)
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error(1, errno, "send socket creat failed!\n");
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res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len);
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if (res < 0)
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printf("get cookie failed: %s\n", strerror(errno));
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res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
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if (res != -1)
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error(1, errno, "socket stat found while flow not active\n");
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for (i = 0; i < 10; i++) {
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res = sendto(s_send, &message, sizeof(message), 0,
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(struct sockaddr *)&si_other, slen);
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if (res == -1)
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error(1, errno, "send\n");
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if (res != sizeof(message))
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error(1, 0, "%uB != %luB\n", res, sizeof(message));
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recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0,
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(struct sockaddr *)&si_me, &slen);
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if (recv_len < 0)
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error(1, errno, "revieve\n");
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res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr),
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sizeof(si_me.sin_addr));
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if (res != 0)
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error(1, EFAULT, "sender addr error: %d\n", res);
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printf("Message received: %c\n", buf);
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res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
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if (res < 0)
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error(1, errno, "lookup sk stat failed, cookie: %lu\n",
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cookie);
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printf("cookie: %lu, uid: 0x%x, Packet Count: %lu,"
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" Bytes Count: %lu\n\n", cookie, dataEntry.uid,
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dataEntry.packets, dataEntry.bytes);
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}
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close(s_send);
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close(s_rcv);
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}
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static int usage(void)
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{
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printf("Usage: ./run_cookie_uid_helper_example.sh"
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" bpfObjName -option\n"
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" -t traffic monitor test\n"
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" -s getsockopt cookie test\n");
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return 1;
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}
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static void finish(int ret)
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{
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test_finish = true;
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}
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int main(int argc, char *argv[])
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{
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int opt;
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bool cfg_test_traffic = false;
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bool cfg_test_cookie = false;
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if (argc != 3)
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return usage();
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while ((opt = getopt(argc, argv, "ts")) != -1) {
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switch (opt) {
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case 't':
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cfg_test_traffic = true;
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break;
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case 's':
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cfg_test_cookie = true;
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break;
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default:
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printf("unknown option %c\n", opt);
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usage();
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return -1;
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}
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}
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maps_create();
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prog_load();
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prog_attach_iptables(argv[2]);
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if (cfg_test_traffic) {
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if (signal(SIGINT, finish) == SIG_ERR)
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error(1, errno, "register SIGINT handler failed");
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if (signal(SIGTERM, finish) == SIG_ERR)
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error(1, errno, "register SIGTERM handler failed");
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while (!test_finish) {
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print_table();
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printf("\n");
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sleep(1);
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};
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} else if (cfg_test_cookie) {
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udp_client();
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}
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close(prog_fd);
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close(map_fd);
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return 0;
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}
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