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bpf: improve selftests and add tests for meta pointer
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Add various test_verifier selftests, and a simple xdp/tc functional
test that is being attached to veths. Also let new versions of clang
use the recently added -mcpu=probe support [1] for the BPF target,
so that it can probe the underlying kernel for BPF insn set extensions.
We could also just set this options always, where older versions just
ignore it and give a note to the user that the -mcpu value is not
supported, but given emitting the note cannot be turned off from clang
side lets not confuse users running selftests with it, thus fallback
to the default generic one when we see that clang doesn't support it.
Also allow CPU option to be overridden in the Makefile from command
line.

  [1] https://github.com/llvm-mirror/llvm/commit/d7276a40d87b89aed89978dec6457a5b8b3a0db5

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Daniel Borkmann authored and David S. Miller committed Sep 26, 2017
1 parent ac29991 commit 22c8852
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Showing 5 changed files with 370 additions and 4 deletions.
21 changes: 17 additions & 4 deletions tools/testing/selftests/bpf/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,10 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
test_align

TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
test_pkt_md_access.o test_xdp_redirect.o sockmap_parse_prog.o sockmap_verdict_prog.o
test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
sockmap_verdict_prog.o

TEST_PROGS := test_kmod.sh test_xdp_redirect.sh
TEST_PROGS := test_kmod.sh test_xdp_redirect.sh test_xdp_meta.sh

include ../lib.mk

Expand All @@ -34,8 +35,20 @@ $(BPFOBJ): force
$(MAKE) -C $(BPFDIR) OUTPUT=$(OUTPUT)/

CLANG ?= clang
LLC ?= llc

PROBE := $(shell llc -march=bpf -mcpu=probe -filetype=null /dev/null 2>&1)

# Let newer LLVM versions transparently probe the kernel for availability
# of full BPF instruction set.
ifeq ($(PROBE),)
CPU ?= probe
else
CPU ?= generic
endif

%.o: %.c
$(CLANG) -I. -I./include/uapi -I../../../include/uapi \
-Wno-compare-distinct-pointer-types \
-O2 -target bpf -c $< -o $@
-Wno-compare-distinct-pointer-types \
-O2 -target bpf -emit-llvm -c $< -o - | \
$(LLC) -march=bpf -mcpu=$(CPU) -filetype=obj -o $@
2 changes: 2 additions & 0 deletions tools/testing/selftests/bpf/bpf_helpers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,8 @@ static unsigned long long (*bpf_get_prandom_u32)(void) =
(void *) BPF_FUNC_get_prandom_u32;
static int (*bpf_xdp_adjust_head)(void *ctx, int offset) =
(void *) BPF_FUNC_xdp_adjust_head;
static int (*bpf_xdp_adjust_meta)(void *ctx, int offset) =
(void *) BPF_FUNC_xdp_adjust_meta;
static int (*bpf_setsockopt)(void *ctx, int level, int optname, void *optval,
int optlen) =
(void *) BPF_FUNC_setsockopt;
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247 changes: 247 additions & 0 deletions tools/testing/selftests/bpf/test_verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6645,6 +6645,253 @@ static struct bpf_test tests[] = {
.errstr = "BPF_END uses reserved fields",
.result = REJECT,
},
{
"meta access, test1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 8),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet, off=-8",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test3",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test4",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_4),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test5",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_4, 3),
BPF_MOV64_IMM(BPF_REG_2, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
BPF_FUNC_xdp_adjust_meta),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_3, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "R3 !read_ok",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test6",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_0, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test7",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test8",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0xFFFF),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test9",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 0xFFFF),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 1),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test10",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_IMM(BPF_REG_5, 42),
BPF_MOV64_IMM(BPF_REG_6, 24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_5, -8),
BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_6, -8),
BPF_LDX_MEM(BPF_DW, BPF_REG_5, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JGT, BPF_REG_5, 100, 6),
BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_5),
BPF_MOV64_REG(BPF_REG_5, BPF_REG_3),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_5, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_2, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid access to packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test11",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_IMM(BPF_REG_5, 42),
BPF_MOV64_IMM(BPF_REG_6, 24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_5, -8),
BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_6, -8),
BPF_LDX_MEM(BPF_DW, BPF_REG_5, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JGT, BPF_REG_5, 100, 6),
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_5),
BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_5, BPF_REG_5, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"meta access, test12",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_5, BPF_REG_3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 16),
BPF_JMP_REG(BPF_JGT, BPF_REG_5, BPF_REG_4, 5),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_3, 0),
BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 16),
BPF_JMP_REG(BPF_JGT, BPF_REG_5, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
};

static int probe_filter_length(const struct bpf_insn *fp)
Expand Down
53 changes: 53 additions & 0 deletions tools/testing/selftests/bpf/test_xdp_meta.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/pkt_cls.h>

#include "bpf_helpers.h"

#define __round_mask(x, y) ((__typeof__(x))((y) - 1))
#define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1)
#define ctx_ptr(ctx, mem) (void *)(unsigned long)ctx->mem

SEC("t")
int ing_cls(struct __sk_buff *ctx)
{
__u8 *data, *data_meta, *data_end;
__u32 diff = 0;

data_meta = ctx_ptr(ctx, data_meta);
data_end = ctx_ptr(ctx, data_end);
data = ctx_ptr(ctx, data);

if (data + ETH_ALEN > data_end ||
data_meta + round_up(ETH_ALEN, 4) > data)
return TC_ACT_SHOT;

diff |= ((__u32 *)data_meta)[0] ^ ((__u32 *)data)[0];
diff |= ((__u16 *)data_meta)[2] ^ ((__u16 *)data)[2];

return diff ? TC_ACT_SHOT : TC_ACT_OK;
}

SEC("x")
int ing_xdp(struct xdp_md *ctx)
{
__u8 *data, *data_meta, *data_end;
int ret;

ret = bpf_xdp_adjust_meta(ctx, -round_up(ETH_ALEN, 4));
if (ret < 0)
return XDP_DROP;

data_meta = ctx_ptr(ctx, data_meta);
data_end = ctx_ptr(ctx, data_end);
data = ctx_ptr(ctx, data);

if (data + ETH_ALEN > data_end ||
data_meta + round_up(ETH_ALEN, 4) > data)
return XDP_DROP;

__builtin_memcpy(data_meta, data, ETH_ALEN);
return XDP_PASS;
}

char _license[] SEC("license") = "GPL";
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