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323 lines
9.2 KiB
323 lines
9.2 KiB
/* 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 "bpf_insn.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_ATOMIC_OP(BPF_DW, BPF_ADD, 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_ATOMIC_OP(BPF_DW, BPF_ADD, 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, "receive\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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