selftests/bpf: Rewrite recvmsg{4,6} asm progs to c in test_sock_addr

I'll extend them in the next patch. It's easier to work with C
than with asm.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210127232853.3753823-4-sdf@google.com

tools/testing/selftests/bpf/progs/recvmsg4_prog.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/stddef.h>
+#include <linux/bpf.h>
+#include <linux/in.h>
+#include <sys/socket.h>
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define SERV4_IP		0xc0a801feU /* 192.168.1.254 */
+#define SERV4_PORT		4040
+
+SEC("cgroup/recvmsg4")
+int recvmsg4_prog(struct bpf_sock_addr *ctx)
+{
+	struct bpf_sock *sk;
+	__u32 user_ip4;
+	__u16 user_port;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	if (sk->family != AF_INET)
+		return 1;
+
+	if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
+		return 1;
+
+	ctx->user_ip4 = bpf_htonl(SERV4_IP);
+	ctx->user_port = bpf_htons(SERV4_PORT);
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/recvmsg6_prog.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/stddef.h>
+#include <linux/bpf.h>
+#include <linux/in6.h>
+#include <sys/socket.h>
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define SERV6_IP_0		0xfaceb00c /* face:b00c:1234:5678::abcd */
+#define SERV6_IP_1		0x12345678
+#define SERV6_IP_2		0x00000000
+#define SERV6_IP_3		0x0000abcd
+#define SERV6_PORT		6060
+
+SEC("cgroup/recvmsg6")
+int recvmsg6_prog(struct bpf_sock_addr *ctx)
+{
+	struct bpf_sock *sk;
+	__u32 user_ip4;
+	__u16 user_port;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	if (sk->family != AF_INET6)
+		return 1;
+
+	if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
+		return 1;
+
+	ctx->user_ip6[0] = bpf_htonl(SERV6_IP_0);
+	ctx->user_ip6[1] = bpf_htonl(SERV6_IP_1);
+	ctx->user_ip6[2] = bpf_htonl(SERV6_IP_2);
+	ctx->user_ip6[3] = bpf_htonl(SERV6_IP_3);
+	ctx->user_port = bpf_htons(SERV6_PORT);
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_sock_addr.c

@@ -31,6 +31,8 @@
 #define CONNECT6_PROG_PATH	"./connect6_prog.o"
 #define SENDMSG4_PROG_PATH	"./sendmsg4_prog.o"
 #define SENDMSG6_PROG_PATH	"./sendmsg6_prog.o"
+#define RECVMSG4_PROG_PATH	"./recvmsg4_prog.o"
+#define RECVMSG6_PROG_PATH	"./recvmsg6_prog.o"
 #define BIND4_PROG_PATH		"./bind4_prog.o"
 #define BIND6_PROG_PATH		"./bind6_prog.o"
 
@@ -94,10 +96,10 @@ static int sendmsg_deny_prog_load(const struct sock_addr_test *test);
 static int recvmsg_allow_prog_load(const struct sock_addr_test *test);
 static int recvmsg_deny_prog_load(const struct sock_addr_test *test);
 static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test);
-static int recvmsg4_rw_asm_prog_load(const struct sock_addr_test *test);
+static int recvmsg4_rw_c_prog_load(const struct sock_addr_test *test);
 static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test);
 static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test);
-static int recvmsg6_rw_asm_prog_load(const struct sock_addr_test *test);
+static int recvmsg6_rw_c_prog_load(const struct sock_addr_test *test);
 static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test);
 static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test);
 static int sendmsg6_rw_wildcard_prog_load(const struct sock_addr_test *test);
@@ -573,8 +575,8 @@ static struct sock_addr_test tests[] = {
 		LOAD_REJECT,
 	},
 	{
-		"recvmsg4: rewrite IP & port (asm)",
-		recvmsg4_rw_asm_prog_load,
+		"recvmsg4: rewrite IP & port (C)",
+		recvmsg4_rw_c_prog_load,
 		BPF_CGROUP_UDP4_RECVMSG,
 		BPF_CGROUP_UDP4_RECVMSG,
 		AF_INET,
@@ -587,8 +589,8 @@ static struct sock_addr_test tests[] = {
 		SUCCESS,
 	},
 	{
-		"recvmsg6: rewrite IP & port (asm)",
-		recvmsg6_rw_asm_prog_load,
+		"recvmsg6: rewrite IP & port (C)",
+		recvmsg6_rw_c_prog_load,
 		BPF_CGROUP_UDP6_RECVMSG,
 		BPF_CGROUP_UDP6_RECVMSG,
 		AF_INET6,
@@ -786,45 +788,9 @@ static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test)
 	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
 }
 
-static int recvmsg4_rw_asm_prog_load(const struct sock_addr_test *test)
+static int recvmsg4_rw_c_prog_load(const struct sock_addr_test *test)
 {
-	struct sockaddr_in src4_rw_addr;
-
-	if (mk_sockaddr(AF_INET, SERV4_IP, SERV4_PORT,
-			(struct sockaddr *)&src4_rw_addr,
-			sizeof(src4_rw_addr)) == -1)
-		return -1;
-
-	struct bpf_insn insns[] = {
-		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
-
-		/* if (sk.family == AF_INET && */
-		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
-			    offsetof(struct bpf_sock_addr, family)),
-		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 6),
-
-		/*     sk.type == SOCK_DGRAM)  { */
-		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
-			    offsetof(struct bpf_sock_addr, type)),
-		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_DGRAM, 4),
-
-		/*      user_ip4 = src4_rw_addr.sin_addr */
-		BPF_MOV32_IMM(BPF_REG_7, src4_rw_addr.sin_addr.s_addr),
-		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
-			    offsetof(struct bpf_sock_addr, user_ip4)),
-
-		/*      user_port = src4_rw_addr.sin_port */
-		BPF_MOV32_IMM(BPF_REG_7, src4_rw_addr.sin_port),
-		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
-			    offsetof(struct bpf_sock_addr, user_port)),
-		/* } */
-
-		/* return 1 */
-		BPF_MOV64_IMM(BPF_REG_0, 1),
-		BPF_EXIT_INSN(),
-	};
-
-	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
+	return load_path(test, RECVMSG4_PROG_PATH);
 }
 
 static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test)
@@ -890,37 +856,9 @@ static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test)
 	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_REWRITE_IP);
 }
 
-static int recvmsg6_rw_asm_prog_load(const struct sock_addr_test *test)
+static int recvmsg6_rw_c_prog_load(const struct sock_addr_test *test)
 {
-	struct sockaddr_in6 src6_rw_addr;
-
-	if (mk_sockaddr(AF_INET6, SERV6_IP, SERV6_PORT,
-			(struct sockaddr *)&src6_rw_addr,
-			sizeof(src6_rw_addr)) == -1)
-		return -1;
-
-	struct bpf_insn insns[] = {
-		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
-
-		/* if (sk.family == AF_INET6) { */
-		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
-			    offsetof(struct bpf_sock_addr, family)),
-		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET6, 10),
-
-		STORE_IPV6(user_ip6, src6_rw_addr.sin6_addr.s6_addr32),
-
-		/*      user_port = dst6_rw_addr.sin6_port */
-		BPF_MOV32_IMM(BPF_REG_7, src6_rw_addr.sin6_port),
-		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
-			    offsetof(struct bpf_sock_addr, user_port)),
-		/* } */
-
-		/* return 1 */
-		BPF_MOV64_IMM(BPF_REG_0, 1),
-		BPF_EXIT_INSN(),
-	};
-
-	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
+	return load_path(test, RECVMSG6_PROG_PATH);
 }
 
 static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test)