Merge branch 'bpf: Add hwtstamp field for the sockops prog'

Martin KaFai Lau says:

====================

From: Martin KaFai Lau <martin.lau@kernel.org>

The bpf-tc prog has already been able to access the
skb_hwtstamps(skb)->hwtstamp.  This set extends the same hwtstamp
access to the sockops prog.

v2:
- Fixed the btf_dump selftest which depends on the
  last member of 'struct bpf_sock_ops'.
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

include/uapi/linux/bpf.h

@@ -6445,6 +6445,7 @@ struct bpf_sock_ops {
 				 * the outgoing header has not
 				 * been written yet.
 				 */
+	__u64 skb_hwtstamp;
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */

net/core/filter.c

@@ -8925,6 +8925,10 @@ static bool sock_ops_is_valid_access(int off, int size,
 			bpf_ctx_record_field_size(info, size_default);
 			return bpf_ctx_narrow_access_ok(off, size,
 							size_default);
+		case offsetof(struct bpf_sock_ops, skb_hwtstamp):
+			if (size != sizeof(__u64))
+				return false;
+			break;
 		default:
 			if (size != size_default)
 				return false;
@@ -9108,21 +9112,21 @@ static struct bpf_insn *bpf_convert_tstamp_type_read(const struct bpf_insn *si,
 	return insn;
 }
 
-static struct bpf_insn *bpf_convert_shinfo_access(const struct bpf_insn *si,
+static struct bpf_insn *bpf_convert_shinfo_access(__u8 dst_reg, __u8 skb_reg,
 						  struct bpf_insn *insn)
 {
 	/* si->dst_reg = skb_shinfo(SKB); */
 #ifdef NET_SKBUFF_DATA_USES_OFFSET
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
-			      BPF_REG_AX, si->src_reg,
+			      BPF_REG_AX, skb_reg,
 			      offsetof(struct sk_buff, end));
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, head),
-			      si->dst_reg, si->src_reg,
+			      dst_reg, skb_reg,
 			      offsetof(struct sk_buff, head));
-	*insn++ = BPF_ALU64_REG(BPF_ADD, si->dst_reg, BPF_REG_AX);
+	*insn++ = BPF_ALU64_REG(BPF_ADD, dst_reg, BPF_REG_AX);
 #else
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
-			      si->dst_reg, si->src_reg,
+			      dst_reg, skb_reg,
 			      offsetof(struct sk_buff, end));
 #endif
 
@@ -9515,7 +9519,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 		break;
 
 	case offsetof(struct __sk_buff, gso_segs):
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*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,
@@ -9523,7 +9527,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 						     target_size));
 		break;
 	case offsetof(struct __sk_buff, gso_size):
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_size),
 				      si->dst_reg, si->dst_reg,
 				      bpf_target_off(struct skb_shared_info,
@@ -9550,7 +9554,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 		BUILD_BUG_ON(sizeof_field(struct skb_shared_hwtstamps, hwtstamp) != 8);
 		BUILD_BUG_ON(offsetof(struct skb_shared_hwtstamps, hwtstamp) != 0);
 
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*insn++ = BPF_LDX_MEM(BPF_DW,
 				      si->dst_reg, si->dst_reg,
 				      bpf_target_off(struct skb_shared_info,
@@ -10400,6 +10404,25 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 						       tcp_flags),
 				      si->dst_reg, si->dst_reg, off);
 		break;
+	case offsetof(struct bpf_sock_ops, skb_hwtstamp): {
+		struct bpf_insn *jmp_on_null_skb;
+
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sock_ops_kern,
+						       skb),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_sock_ops_kern,
+					       skb));
+		/* Reserve one insn to test skb == NULL */
+		jmp_on_null_skb = insn++;
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->dst_reg, insn);
+		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct skb_shared_info,
+						     hwtstamps, 8,
+						     target_size));
+		*jmp_on_null_skb = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0,
+					       insn - jmp_on_null_skb - 1);
+		break;
+	}
 	}
 	return insn - insn_buf;
 }

tools/include/uapi/linux/bpf.h

@@ -6445,6 +6445,7 @@ struct bpf_sock_ops {
 				 * the outgoing header has not
 				 * been written yet.
 				 */
+	__u64 skb_hwtstamp;
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */

tools/testing/selftests/bpf/prog_tests/btf_dump.c

@@ -791,11 +791,11 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
 	TEST_BTF_DUMP_DATA_OVER(btf, d, "struct", str, struct bpf_sock_ops,
 				sizeof(struct bpf_sock_ops) - 1,
 				"(struct bpf_sock_ops){\n\t.op = (__u32)1,\n",
-				{ .op = 1, .skb_tcp_flags = 2});
+				{ .op = 1, .skb_hwtstamp = 2});
 	TEST_BTF_DUMP_DATA_OVER(btf, d, "struct", str, struct bpf_sock_ops,
 				sizeof(struct bpf_sock_ops) - 1,
 				"(struct bpf_sock_ops){\n\t.op = (__u32)1,\n",
-				{ .op = 1, .skb_tcp_flags = 0});
+				{ .op = 1, .skb_hwtstamp = 0});
 }
 
 static void test_btf_dump_var_data(struct btf *btf, struct btf_dump *d,

tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c

@@ -485,7 +485,7 @@ static void misc(void)
 			goto check_linum;
 
 		ret = read(sk_fds.passive_fd, recv_msg, sizeof(recv_msg));
-		if (ASSERT_EQ(ret, sizeof(send_msg), "read(msg)"))
+		if (!ASSERT_EQ(ret, sizeof(send_msg), "read(msg)"))
 			goto check_linum;
 	}
 
@@ -505,6 +505,8 @@ static void misc(void)
 
 	ASSERT_EQ(misc_skel->bss->nr_fin, 1, "unexpected nr_fin");
 
+	ASSERT_EQ(misc_skel->bss->nr_hwtstamp, 0, "nr_hwtstamp");
+
 check_linum:
 	ASSERT_FALSE(check_error_linum(&sk_fds), "check_error_linum");
 	sk_fds_close(&sk_fds);
@@ -539,7 +541,7 @@ void test_tcp_hdr_options(void)
 		goto skel_destroy;
 
 	cg_fd = test__join_cgroup(CG_NAME);
-	if (ASSERT_GE(cg_fd, 0, "join_cgroup"))
+	if (!ASSERT_GE(cg_fd, 0, "join_cgroup"))
 		goto skel_destroy;
 
 	for (i = 0; i < ARRAY_SIZE(tests); i++) {

tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c

@@ -27,6 +27,7 @@ unsigned int nr_pure_ack = 0;
 unsigned int nr_data = 0;
 unsigned int nr_syn = 0;
 unsigned int nr_fin = 0;
+unsigned int nr_hwtstamp = 0;
 
 /* Check the header received from the active side */
 static int __check_active_hdr_in(struct bpf_sock_ops *skops, bool check_syn)
@@ -146,6 +147,9 @@ static int check_active_hdr_in(struct bpf_sock_ops *skops)
 	if (th->ack && !th->fin && tcp_hdrlen(th) == skops->skb_len)
 		nr_pure_ack++;
 
+	if (skops->skb_hwtstamp)
+		nr_hwtstamp++;
+
 	return CG_OK;
 }