Commit 0367d0a2 authored by Nikita V. Shirokov's avatar Nikita V. Shirokov Committed by Daniel Borkmann

bpf: adding tests for bpf_xdp_adjust_tail

adding selftests for bpf_xdp_adjust_tail helper. in this synthetic test
we are testing that 1) if data_end < data helper will return EINVAL
2) for normal use case packet's length would be reduced.
Signed-off-by: default avatarNikita V. Shirokov <tehnerd@tehnerd.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 587b80cc
......@@ -755,6 +755,13 @@ union bpf_attr {
* @addr: pointer to struct sockaddr to bind socket to
* @addr_len: length of sockaddr structure
* Return: 0 on success or negative error code
*
* int bpf_xdp_adjust_tail(xdp_md, delta)
* Adjust the xdp_md.data_end by delta. Only shrinking of packet's
* size is supported.
* @xdp_md: pointer to xdp_md
* @delta: A negative integer to be added to xdp_md.data_end
* Return: 0 on success or negative on error
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
......@@ -821,7 +828,8 @@ union bpf_attr {
FN(msg_apply_bytes), \
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind),
FN(bind), \
FN(xdp_adjust_tail),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
......
......@@ -31,7 +31,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \
test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \
sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o
sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o
# Order correspond to 'make run_tests' order
TEST_PROGS := test_kmod.sh \
......
......@@ -96,6 +96,9 @@ static int (*bpf_msg_pull_data)(void *ctx, int start, int end, int flags) =
(void *) BPF_FUNC_msg_pull_data;
static int (*bpf_bind)(void *ctx, void *addr, int addr_len) =
(void *) BPF_FUNC_bind;
static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =
(void *) BPF_FUNC_xdp_adjust_tail;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
......
/* SPDX-License-Identifier: GPL-2.0
* Copyright (c) 2018 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include "bpf_helpers.h"
int _version SEC("version") = 1;
SEC("xdp_adjust_tail")
int _xdp_adjust_tail(struct xdp_md *xdp)
{
void *data_end = (void *)(long)xdp->data_end;
void *data = (void *)(long)xdp->data;
int offset = 0;
if (data_end - data == 54)
offset = 256;
else
offset = 20;
if (bpf_xdp_adjust_tail(xdp, 0 - offset))
return XDP_DROP;
return XDP_TX;
}
char _license[] SEC("license") = "GPL";
......@@ -166,6 +166,37 @@ static void test_xdp(void)
bpf_object__close(obj);
}
static void test_xdp_adjust_tail(void)
{
const char *file = "./test_adjust_tail.o";
struct bpf_object *obj;
char buf[128];
__u32 duration, retval, size;
int err, prog_fd;
err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
if (err) {
error_cnt++;
return;
}
err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
buf, &size, &retval, &duration);
CHECK(err || errno || retval != XDP_DROP,
"ipv4", "err %d errno %d retval %d size %d\n",
err, errno, retval, size);
err = bpf_prog_test_run(prog_fd, 1, &pkt_v6, sizeof(pkt_v6),
buf, &size, &retval, &duration);
CHECK(err || errno || retval != XDP_TX || size != 54,
"ipv6", "err %d errno %d retval %d size %d\n",
err, errno, retval, size);
bpf_object__close(obj);
}
#define MAGIC_VAL 0x1234
#define NUM_ITER 100000
#define VIP_NUM 5
......@@ -1177,6 +1208,7 @@ int main(void)
{
test_pkt_access();
test_xdp();
test_xdp_adjust_tail();
test_l4lb_all();
test_xdp_noinline();
test_tcp_estats();
......
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