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authorEric Dumazet <edumazet@google.com>2019-01-23 09:22:27 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2019-01-24 10:49:05 +0100
commitd9ff286a0f59fa7843549e49bd240393dd7d8b87 (patch)
treee35b062f71cf6970b8fa2e05e6d9feb0687da8a3 /tools
parent866e6ac47409f0bd12398b777fef61fb51ce3680 (diff)
bpf: allow BPF programs access skb_shared_info->gso_segs field
This adds the ability to read gso_segs from a BPF program. v3: Use BPF_REG_AX instead of BPF_REG_TMP for the temporary register, as suggested by Martin. v2: refined Eddie Hao patch to address Alexei feedback. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Eddie Hao <eddieh@google.com> Cc: Martin KaFai Lau <kafai@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/include/uapi/linux/bpf.h1
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c36
2 files changed, 37 insertions, 0 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 91c43884f295..2940a9854f6d 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2540,6 +2540,7 @@ struct __sk_buff {
__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
__u64 tstamp;
__u32 wire_len;
+ __u32 gso_segs;
};
struct bpf_tunnel_key {
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 4f67afeec8d9..e4fef6ca8071 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -5664,6 +5664,42 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
},
{
+ "read gso_segs from CGROUP_SKB",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, gso_segs)),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "write gso_segs from CGROUP_SKB",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0,
+ offsetof(struct __sk_buff, gso_segs)),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .result_unpriv = REJECT,
+ .errstr = "invalid bpf_context access off=164 size=4",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "read gso_segs from CLS",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, gso_segs)),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
"multiple registers share map_lookup_elem result",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 10),