diff options
Diffstat (limited to 'samples/bpf/cookie_uid_helper_example.c')
-rw-r--r-- | samples/bpf/cookie_uid_helper_example.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/samples/bpf/cookie_uid_helper_example.c b/samples/bpf/cookie_uid_helper_example.c new file mode 100644 index 000000000000..b08ab4e88929 --- /dev/null +++ b/samples/bpf/cookie_uid_helper_example.c @@ -0,0 +1,321 @@ +/* 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 -option + * option: + * -t: do traffic monitoring test, the program will continuously + * print out network traffic happens after program started A sample + * output 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 + * + * -s: do getsockopt SO_COOKIE test, the program will set up a pair of + * UDP sockets and send packets between them. And read out the traffic data + * directly from the ebpf map based on the socket cookie. + * + * 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 <net/if.h> +#include <signal.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" + +#define PORT 8888 + +struct stats { + uint32_t uid; + uint64_t packets; + uint64_t bytes; +}; + +static int map_fd, prog_fd; + +static bool test_finish; + +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 + (__s16)offsetof(struct stats, uid)), + BPF_ST_MEM(BPF_DW, BPF_REG_10, + -32 + (__s16)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 + (__s16)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 OUTPUT -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; + int 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); + } + } +} + +static void udp_client(void) +{ + struct sockaddr_in si_other = {0}; + struct sockaddr_in si_me = {0}; + struct stats dataEntry; + int s_rcv, s_send, i, recv_len; + char message = 'a'; + char buf; + uint64_t cookie; + int res; + socklen_t cookie_len = sizeof(cookie); + socklen_t slen = sizeof(si_other); + + s_rcv = socket(PF_INET, SOCK_DGRAM, 0); + if (s_rcv < 0) + error(1, errno, "rcv socket creat failed!\n"); + si_other.sin_family = AF_INET; + si_other.sin_port = htons(PORT); + if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0) + error(1, errno, "inet_aton\n"); + if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1) + error(1, errno, "bind\n"); + s_send = socket(PF_INET, SOCK_DGRAM, 0); + if (s_send < 0) + error(1, errno, "send socket creat failed!\n"); + res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len); + if (res < 0) + printf("get cookie failed: %s\n", strerror(errno)); + res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry); + if (res != -1) + error(1, errno, "socket stat found while flow not active\n"); + for (i = 0; i < 10; i++) { + res = sendto(s_send, &message, sizeof(message), 0, + (struct sockaddr *)&si_other, slen); + if (res == -1) + error(1, errno, "send\n"); + if (res != sizeof(message)) + error(1, 0, "%uB != %luB\n", res, sizeof(message)); + recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0, + (struct sockaddr *)&si_me, &slen); + if (recv_len < 0) + error(1, errno, "revieve\n"); + res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr), + sizeof(si_me.sin_addr)); + if (res != 0) + error(1, EFAULT, "sender addr error: %d\n", res); + printf("Message received: %c\n", buf); + res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry); + if (res < 0) + error(1, errno, "lookup sk stat failed, cookie: %lu\n", + cookie); + printf("cookie: %lu, uid: 0x%x, Packet Count: %lu," + " Bytes Count: %lu\n\n", cookie, dataEntry.uid, + dataEntry.packets, dataEntry.bytes); + } + close(s_send); + close(s_rcv); +} + +static int usage(void) +{ + printf("Usage: ./run_cookie_uid_helper_example.sh" + " bpfObjName -option\n" + " -t traffic monitor test\n" + " -s getsockopt cookie test\n"); + return 1; +} + +static void finish(int ret) +{ + test_finish = true; +} + +int main(int argc, char *argv[]) +{ + int opt; + bool cfg_test_traffic = false; + bool cfg_test_cookie = false; + + if (argc != 3) + return usage(); + while ((opt = getopt(argc, argv, "ts")) != -1) { + switch (opt) { + case 't': + cfg_test_traffic = true; + break; + case 's': + cfg_test_cookie = true; + break; + + default: + printf("unknown option %c\n", opt); + usage(); + return -1; + } + } + maps_create(); + prog_load(); + prog_attach_iptables(argv[2]); + if (cfg_test_traffic) { + if (signal(SIGINT, finish) == SIG_ERR) + error(1, errno, "register handler failed"); + while (!test_finish) { + print_table(); + printf("\n"); + sleep(1); + }; + } else if (cfg_test_cookie) { + udp_client(); + } + close(prog_fd); + close(map_fd); + return 0; +} |