112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) 2019 Richard Palethorpe <rpalethorpe@suse.com>
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*
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* Trivial Extended Berkeley Packet Filter (eBPF) test.
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*
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* Sanity check loading and running bytecode.
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*
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* Test flow:
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* 1. Create array map
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* 2. Load eBPF program
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* 3. Attach program to socket
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* 4. Send packet on socket
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* 5. This should trigger eBPF program which writes to array map
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* 6. Verify array map was written to
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*/
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/*
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* If test is executed in a loop and limit for locked memory (ulimit -l) is
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* too low bpf() call can fail with EPERM due to deffered freeing.
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*/
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#include <limits.h>
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#include <string.h>
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#include <stdio.h>
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#include "config.h"
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#include "tst_test.h"
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#include "bpf_common.h"
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const char MSG[] = "Ahoj!";
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static char *msg;
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static char *log;
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static union bpf_attr *attr;
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int load_prog(int fd)
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{
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/*
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* The following is a byte code template. We copy it to a guarded buffer and
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* substitute the runtime value of our map file descriptor.
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*
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* r0 - r10 = registers 0 to 10
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* r0 = return code
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* r1 - r5 = scratch registers, used for function arguments
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* r6 - r9 = registers preserved across function calls
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* fp/r10 = stack frame pointer
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*/
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struct bpf_insn PROG[] = {
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/* Load the map FD into r1 (place holder) */
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BPF_LD_MAP_FD(BPF_REG_1, fd),
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/* Put (key = 0) on stack and key ptr into r2 */
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BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), /* r2 = fp */
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), /* r2 = r2 - 8 */
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BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), /* *r2 = 0 */
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/* r0 = bpf_map_lookup_elem(r1, r2) */
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BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
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/* if r0 == 0 goto exit */
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BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
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/* Set map[0] = 1 */
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BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), /* r1 = r0 */
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BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 1), /* *r1 = 1 */
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BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */
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BPF_EXIT_INSN(), /* return r0 */
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};
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bpf_init_prog_attr(attr, PROG, sizeof(PROG), log, BUFSIZ);
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return bpf_load_prog(attr, log);
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}
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void setup(void)
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{
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rlimit_bump_memlock();
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memcpy(msg, MSG, sizeof(MSG));
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}
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void run(void)
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{
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int map_fd, prog_fd;
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uint32_t key = 0;
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uint64_t val;
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map_fd = bpf_map_array_create(1);
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prog_fd = load_prog(map_fd);
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bpf_run_prog(prog_fd, msg, sizeof(MSG));
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SAFE_CLOSE(prog_fd);
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bpf_map_array_get(map_fd, &key, &val);
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if (val != 1) {
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tst_res(TFAIL,
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"val = %lu, but should be val = 1",
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val);
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} else {
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tst_res(TPASS, "val = 1");
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}
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SAFE_CLOSE(map_fd);
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}
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static struct tst_test test = {
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.setup = setup,
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.test_all = run,
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.min_kver = "3.19",
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.bufs = (struct tst_buffers []) {
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{&log, .size = BUFSIZ},
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{&attr, .size = sizeof(*attr)},
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{&msg, .size = sizeof(MSG)},
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{},
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}
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};
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