@@ -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 {
@@ -6700,6 +6700,27 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
target_size));
break;
+ case offsetof(struct __sk_buff, gso_segs):
+ /* si->dst_reg = skb_shinfo(SKB); */
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, head),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_buff, head));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
+ BPF_REG_AX, si->src_reg,
+ offsetof(struct sk_buff, end));
+ *insn++ = BPF_ALU64_REG(BPF_ADD, si->dst_reg, BPF_REG_AX);
+#else
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_buff, end));
+#endif
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_segs),
+ si->dst_reg, si->dst_reg,
+ bpf_target_off(struct skb_shared_info,
+ gso_segs, 2,
+ target_size));
+ break;
case offsetof(struct __sk_buff, wire_len):
BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, pkt_len) != 4);
@@ -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 {
@@ -5663,6 +5663,42 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
.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 = {
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> --- include/uapi/linux/bpf.h | 1 + net/core/filter.c | 21 ++++++++++++ tools/include/uapi/linux/bpf.h | 1 + tools/testing/selftests/bpf/test_verifier.c | 36 +++++++++++++++++++++ 4 files changed, 59 insertions(+)