bpf: Refactor sock_ops_convert_ctx_access

The next patch will introduce a new "struct bpf_tcp_sock" which
exposes the same tcp_sock's fields already exposed in
"struct bpf_sock_ops".

This patch refactor the existing convert_ctx_access() codes for
"struct bpf_sock_ops" to get them ready to be reused for
"struct bpf_tcp_sock".  The "rtt_min" is not refactored
in this patch because its handling is different from other
fields.

The SOCK_OPS_GET_TCP_SOCK_FIELD is new. All other SOCK_OPS_XXX_FIELD
changes are code move only.
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

net/core/filter.c

@@ -5030,6 +5030,54 @@ static const struct bpf_func_proto bpf_lwt_seg6_adjust_srh_proto = {
 };
 #endif /* CONFIG_IPV6_SEG6_BPF */
 
+#define CONVERT_COMMON_TCP_SOCK_FIELDS(md_type, CONVERT)		\
+do {									\
+	switch (si->off) {						\
+	case offsetof(md_type, snd_cwnd):				\
+		CONVERT(snd_cwnd); break;				\
+	case offsetof(md_type, srtt_us):				\
+		CONVERT(srtt_us); break;				\
+	case offsetof(md_type, snd_ssthresh):				\
+		CONVERT(snd_ssthresh); break;				\
+	case offsetof(md_type, rcv_nxt):				\
+		CONVERT(rcv_nxt); break;				\
+	case offsetof(md_type, snd_nxt):				\
+		CONVERT(snd_nxt); break;				\
+	case offsetof(md_type, snd_una):				\
+		CONVERT(snd_una); break;				\
+	case offsetof(md_type, mss_cache):				\
+		CONVERT(mss_cache); break;				\
+	case offsetof(md_type, ecn_flags):				\
+		CONVERT(ecn_flags); break;				\
+	case offsetof(md_type, rate_delivered):				\
+		CONVERT(rate_delivered); break;				\
+	case offsetof(md_type, rate_interval_us):			\
+		CONVERT(rate_interval_us); break;			\
+	case offsetof(md_type, packets_out):				\
+		CONVERT(packets_out); break;				\
+	case offsetof(md_type, retrans_out):				\
+		CONVERT(retrans_out); break;				\
+	case offsetof(md_type, total_retrans):				\
+		CONVERT(total_retrans); break;				\
+	case offsetof(md_type, segs_in):				\
+		CONVERT(segs_in); break;				\
+	case offsetof(md_type, data_segs_in):				\
+		CONVERT(data_segs_in); break;				\
+	case offsetof(md_type, segs_out):				\
+		CONVERT(segs_out); break;				\
+	case offsetof(md_type, data_segs_out):				\
+		CONVERT(data_segs_out); break;				\
+	case offsetof(md_type, lost_out):				\
+		CONVERT(lost_out); break;				\
+	case offsetof(md_type, sacked_out):				\
+		CONVERT(sacked_out); break;				\
+	case offsetof(md_type, bytes_received):				\
+		CONVERT(bytes_received); break;				\
+	case offsetof(md_type, bytes_acked):				\
+		CONVERT(bytes_acked); break;				\
+	}								\
+} while (0)
+
 #ifdef CONFIG_INET
 static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple,
 			      int dif, int sdif, u8 family, u8 proto)
@@ -7196,6 +7244,85 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 	struct bpf_insn *insn = insn_buf;
 	int off;
 
+/* Helper macro for adding read access to tcp_sock or sock fields. */
+#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \
+	do {								      \
+		BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) >		      \
+			     FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD));   \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern,     \
+						is_fullsock),		      \
+				      si->dst_reg, si->src_reg,		      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+					       is_fullsock));		      \
+		*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 2);	      \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern, sk),\
+				      si->dst_reg, si->src_reg,		      \
+				      offsetof(struct bpf_sock_ops_kern, sk));\
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(OBJ,		      \
+						       OBJ_FIELD),	      \
+				      si->dst_reg, si->dst_reg,		      \
+				      offsetof(OBJ, OBJ_FIELD));	      \
+	} while (0)
+
+#define SOCK_OPS_GET_TCP_SOCK_FIELD(FIELD) \
+		SOCK_OPS_GET_FIELD(FIELD, FIELD, struct tcp_sock)
+
+/* Helper macro for adding write access to tcp_sock or sock fields.
+ * The macro is called with two registers, dst_reg which contains a pointer
+ * to ctx (context) and src_reg which contains the value that should be
+ * stored. However, we need an additional register since we cannot overwrite
+ * dst_reg because it may be used later in the program.
+ * Instead we "borrow" one of the other register. We first save its value
+ * into a new (temp) field in bpf_sock_ops_kern, use it, and then restore
+ * it at the end of the macro.
+ */
+#define SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \
+	do {								      \
+		int reg = BPF_REG_9;					      \
+		BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) >		      \
+			     FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD));   \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, reg,		      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+					       temp));			      \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern,     \
+						is_fullsock),		      \
+				      reg, si->dst_reg,			      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+					       is_fullsock));		      \
+		*insn++ = BPF_JMP_IMM(BPF_JEQ, reg, 0, 2);		      \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern, sk),\
+				      reg, si->dst_reg,			      \
+				      offsetof(struct bpf_sock_ops_kern, sk));\
+		*insn++ = BPF_STX_MEM(BPF_FIELD_SIZEOF(OBJ, OBJ_FIELD),	      \
+				      reg, si->src_reg,			      \
+				      offsetof(OBJ, OBJ_FIELD));	      \
+		*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->dst_reg,		      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+					       temp));			      \
+	} while (0)
+
+#define SOCK_OPS_GET_OR_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ, TYPE)	      \
+	do {								      \
+		if (TYPE == BPF_WRITE)					      \
+			SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ);	      \
+		else							      \
+			SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ);	      \
+	} while (0)
+
+	CONVERT_COMMON_TCP_SOCK_FIELDS(struct bpf_sock_ops,
+				       SOCK_OPS_GET_TCP_SOCK_FIELD);
+
+	if (insn > insn_buf)
+		return insn - insn_buf;
+
 	switch (si->off) {
 	case offsetof(struct bpf_sock_ops, op) ...
 	     offsetof(struct bpf_sock_ops, replylong[3]):
@@ -7353,175 +7480,15 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 				      FIELD_SIZEOF(struct minmax_sample, t));
 		break;
 
-/* Helper macro for adding read access to tcp_sock or sock fields. */
-#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \
-	do {								      \
-		BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) >		      \
-			     FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD));   \
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
-						struct bpf_sock_ops_kern,     \
-						is_fullsock),		      \
-				      si->dst_reg, si->src_reg,		      \
-				      offsetof(struct bpf_sock_ops_kern,      \
-					       is_fullsock));		      \
-		*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 2);	      \
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
-						struct bpf_sock_ops_kern, sk),\
-				      si->dst_reg, si->src_reg,		      \
-				      offsetof(struct bpf_sock_ops_kern, sk));\
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(OBJ,		      \
-						       OBJ_FIELD),	      \
-				      si->dst_reg, si->dst_reg,		      \
-				      offsetof(OBJ, OBJ_FIELD));	      \
-	} while (0)
-
-/* Helper macro for adding write access to tcp_sock or sock fields.
- * The macro is called with two registers, dst_reg which contains a pointer
- * to ctx (context) and src_reg which contains the value that should be
- * stored. However, we need an additional register since we cannot overwrite
- * dst_reg because it may be used later in the program.
- * Instead we "borrow" one of the other register. We first save its value
- * into a new (temp) field in bpf_sock_ops_kern, use it, and then restore
- * it at the end of the macro.
- */
-#define SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \
-	do {								      \
-		int reg = BPF_REG_9;					      \
-		BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) >		      \
-			     FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD));   \
-		if (si->dst_reg == reg || si->src_reg == reg)		      \
-			reg--;						      \
-		if (si->dst_reg == reg || si->src_reg == reg)		      \
-			reg--;						      \
-		*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, reg,		      \
-				      offsetof(struct bpf_sock_ops_kern,      \
-					       temp));			      \
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
-						struct bpf_sock_ops_kern,     \
-						is_fullsock),		      \
-				      reg, si->dst_reg,			      \
-				      offsetof(struct bpf_sock_ops_kern,      \
-					       is_fullsock));		      \
-		*insn++ = BPF_JMP_IMM(BPF_JEQ, reg, 0, 2);		      \
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
-						struct bpf_sock_ops_kern, sk),\
-				      reg, si->dst_reg,			      \
-				      offsetof(struct bpf_sock_ops_kern, sk));\
-		*insn++ = BPF_STX_MEM(BPF_FIELD_SIZEOF(OBJ, OBJ_FIELD),	      \
-				      reg, si->src_reg,			      \
-				      offsetof(OBJ, OBJ_FIELD));	      \
-		*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->dst_reg,		      \
-				      offsetof(struct bpf_sock_ops_kern,      \
-					       temp));			      \
-	} while (0)
-
-#define SOCK_OPS_GET_OR_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ, TYPE)	      \
-	do {								      \
-		if (TYPE == BPF_WRITE)					      \
-			SOCK_OPS_SET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ);	      \
-		else							      \
-			SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ);	      \
-	} while (0)
-
-	case offsetof(struct bpf_sock_ops, snd_cwnd):
-		SOCK_OPS_GET_FIELD(snd_cwnd, snd_cwnd, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, srtt_us):
-		SOCK_OPS_GET_FIELD(srtt_us, srtt_us, struct tcp_sock);
-		break;
-
 	case offsetof(struct bpf_sock_ops, bpf_sock_ops_cb_flags):
 		SOCK_OPS_GET_FIELD(bpf_sock_ops_cb_flags, bpf_sock_ops_cb_flags,
 				   struct tcp_sock);
 		break;
 
-	case offsetof(struct bpf_sock_ops, snd_ssthresh):
-		SOCK_OPS_GET_FIELD(snd_ssthresh, snd_ssthresh, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, rcv_nxt):
-		SOCK_OPS_GET_FIELD(rcv_nxt, rcv_nxt, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, snd_nxt):
-		SOCK_OPS_GET_FIELD(snd_nxt, snd_nxt, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, snd_una):
-		SOCK_OPS_GET_FIELD(snd_una, snd_una, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, mss_cache):
-		SOCK_OPS_GET_FIELD(mss_cache, mss_cache, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, ecn_flags):
-		SOCK_OPS_GET_FIELD(ecn_flags, ecn_flags, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, rate_delivered):
-		SOCK_OPS_GET_FIELD(rate_delivered, rate_delivered,
-				   struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, rate_interval_us):
-		SOCK_OPS_GET_FIELD(rate_interval_us, rate_interval_us,
-				   struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, packets_out):
-		SOCK_OPS_GET_FIELD(packets_out, packets_out, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, retrans_out):
-		SOCK_OPS_GET_FIELD(retrans_out, retrans_out, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, total_retrans):
-		SOCK_OPS_GET_FIELD(total_retrans, total_retrans,
-				   struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, segs_in):
-		SOCK_OPS_GET_FIELD(segs_in, segs_in, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, data_segs_in):
-		SOCK_OPS_GET_FIELD(data_segs_in, data_segs_in, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, segs_out):
-		SOCK_OPS_GET_FIELD(segs_out, segs_out, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, data_segs_out):
-		SOCK_OPS_GET_FIELD(data_segs_out, data_segs_out,
-				   struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, lost_out):
-		SOCK_OPS_GET_FIELD(lost_out, lost_out, struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, sacked_out):
-		SOCK_OPS_GET_FIELD(sacked_out, sacked_out, struct tcp_sock);
-		break;
-
 	case offsetof(struct bpf_sock_ops, sk_txhash):
 		SOCK_OPS_GET_OR_SET_FIELD(sk_txhash, sk_txhash,
 					  struct sock, type);
 		break;
-
-	case offsetof(struct bpf_sock_ops, bytes_received):
-		SOCK_OPS_GET_FIELD(bytes_received, bytes_received,
-				   struct tcp_sock);
-		break;
-
-	case offsetof(struct bpf_sock_ops, bytes_acked):
-		SOCK_OPS_GET_FIELD(bytes_acked, bytes_acked, struct tcp_sock);
-		break;
-
 	}
 	return insn - insn_buf;
 }