selftests: add selftest for UDP SO_PEEK_OFF support

Add the SO_PEEK_OFF selftest for UDP. In this patch, I mainly do
three things:
1. rename tcp_so_peek_off.c
2. adjust for UDP protocol
3. add selftests into it
Suggested-by: Jon Maloy <jmaloy@redhat.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/.gitignore

@@ -34,6 +34,7 @@ scm_pidfd
 scm_rights
 sk_bind_sendto_listen
 sk_connect_zero_addr
+sk_so_peek_off
 socket
 so_incoming_cpu
 so_netns_cookie

tools/testing/selftests/net/Makefile

@@ -80,7 +80,7 @@ TEST_PROGS += io_uring_zerocopy_tx.sh
 TEST_GEN_FILES += bind_bhash
 TEST_GEN_PROGS += sk_bind_sendto_listen
 TEST_GEN_PROGS += sk_connect_zero_addr
-TEST_GEN_PROGS += tcp_so_peek_off
+TEST_GEN_PROGS += sk_so_peek_off
 TEST_PROGS += test_ingress_egress_chaining.sh
 TEST_GEN_PROGS += so_incoming_cpu
 TEST_PROGS += sctp_vrf.sh

tools/testing/selftests/net/tcp_so_peek_off.c → tools/testing/selftests/net/sk_so_peek_off.c

@@ -10,37 +10,41 @@
 #include <arpa/inet.h>
 #include "../kselftest.h"
 
-static char *afstr(int af)
+static char *afstr(int af, int proto)
 {
+	if (proto == IPPROTO_TCP)
 		return af == AF_INET ? "TCP/IPv4" : "TCP/IPv6";
+	else
+		return af == AF_INET ? "UDP/IPv4" : "UDP/IPv6";
 }
 
-int tcp_peek_offset_probe(sa_family_t af)
+int sk_peek_offset_probe(sa_family_t af, int proto)
 {
+	int type = (proto == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM);
 	int optv = 0;
 	int ret = 0;
 	int s;
 
-	s = socket(af, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	s = socket(af, type, proto);
 	if (s < 0) {
 		ksft_perror("Temporary TCP socket creation failed");
 	} else {
 		if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int)))
 			ret = 1;
 		else
-			printf("%s does not support SO_PEEK_OFF\n", afstr(af));
+			printf("%s does not support SO_PEEK_OFF\n", afstr(af, proto));
 		close(s);
 	}
 	return ret;
 }
 
-static void tcp_peek_offset_set(int s, int offset)
+static void sk_peek_offset_set(int s, int offset)
 {
 	if (setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, sizeof(offset)))
 		ksft_perror("Failed to set SO_PEEK_OFF value\n");
 }
 
-static int tcp_peek_offset_get(int s)
+static int sk_peek_offset_get(int s)
 {
 	int offset;
 	socklen_t len = sizeof(offset);
@@ -50,8 +54,9 @@ static int tcp_peek_offset_get(int s)
 	return offset;
 }
 
-static int tcp_peek_offset_test(sa_family_t af)
+static int sk_peek_offset_test(sa_family_t af, int proto)
 {
+	int type = (proto == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM);
 	union {
 		struct sockaddr sa;
 		struct sockaddr_in a4;
@@ -62,13 +67,13 @@ static int tcp_peek_offset_test(sa_family_t af)
 	int recv_sock = 0;
 	int offset = 0;
 	ssize_t len;
-	char buf;
+	char buf[2];
 
 	memset(&a, 0, sizeof(a));
 	a.sa.sa_family = af;
 
-	s[0] = socket(af, SOCK_STREAM, IPPROTO_TCP);
-	s[1] = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
+	s[0] = recv_sock = socket(af, type, proto);
+	s[1] = socket(af, type, proto);
 
 	if (s[0] < 0 || s[1] < 0) {
 		ksft_perror("Temporary socket creation failed\n");
@@ -82,76 +87,78 @@ static int tcp_peek_offset_test(sa_family_t af)
 		ksft_perror("Temporary socket getsockname() failed\n");
 		goto out;
 	}
-	if (listen(s[0], 0) < 0) {
+	if (proto == IPPROTO_TCP && listen(s[0], 0) < 0) {
 		ksft_perror("Temporary socket listen() failed\n");
 		goto out;
 	}
-	if (connect(s[1], &a.sa, sizeof(a)) >= 0 || errno != EINPROGRESS) {
+	if (connect(s[1], &a.sa, sizeof(a)) < 0) {
 		ksft_perror("Temporary socket connect() failed\n");
 		goto out;
 	}
+	if (proto == IPPROTO_TCP) {
 		recv_sock = accept(s[0], NULL, NULL);
 		if (recv_sock <= 0) {
 			ksft_perror("Temporary socket accept() failed\n");
 			goto out;
 		}
+	}
 
 	/* Some basic tests of getting/setting offset */
-	offset = tcp_peek_offset_get(recv_sock);
+	offset = sk_peek_offset_get(recv_sock);
 	if (offset != -1) {
 		ksft_perror("Initial value of socket offset not -1\n");
 		goto out;
 	}
-	tcp_peek_offset_set(recv_sock, 0);
-	offset = tcp_peek_offset_get(recv_sock);
+	sk_peek_offset_set(recv_sock, 0);
+	offset = sk_peek_offset_get(recv_sock);
 	if (offset != 0) {
 		ksft_perror("Failed to set socket offset to 0\n");
 		goto out;
 	}
 
 	/* Transfer a message */
-	if (send(s[1], (char *)("ab"), 2, 0) <= 0 || errno != EINPROGRESS) {
+	if (send(s[1], (char *)("ab"), 2, 0) != 2) {
 		ksft_perror("Temporary probe socket send() failed\n");
 		goto out;
 	}
 	/* Read first byte */
-	len = recv(recv_sock, &buf, 1, MSG_PEEK);
-	if (len != 1 || buf != 'a') {
+	len = recv(recv_sock, buf, 1, MSG_PEEK);
+	if (len != 1 || buf[0] != 'a') {
 		ksft_perror("Failed to read first byte of message\n");
 		goto out;
 	}
-	offset = tcp_peek_offset_get(recv_sock);
+	offset = sk_peek_offset_get(recv_sock);
 	if (offset != 1) {
 		ksft_perror("Offset not forwarded correctly at first byte\n");
 		goto out;
 	}
 	/* Try to read beyond last byte */
-	len = recv(recv_sock, &buf, 2, MSG_PEEK);
-	if (len != 1 || buf != 'b') {
+	len = recv(recv_sock, buf, 2, MSG_PEEK);
+	if (len != 1 || buf[0] != 'b') {
 		ksft_perror("Failed to read last byte of message\n");
 		goto out;
 	}
-	offset = tcp_peek_offset_get(recv_sock);
+	offset = sk_peek_offset_get(recv_sock);
 	if (offset != 2) {
 		ksft_perror("Offset not forwarded correctly at last byte\n");
 		goto out;
 	}
 	/* Flush message */
-	len = recv(recv_sock, NULL, 2, MSG_TRUNC);
+	len = recv(recv_sock, buf, 2, MSG_TRUNC);
 	if (len != 2) {
 		ksft_perror("Failed to flush message\n");
 		goto out;
 	}
-	offset = tcp_peek_offset_get(recv_sock);
+	offset = sk_peek_offset_get(recv_sock);
 	if (offset != 0) {
 		ksft_perror("Offset not reverted correctly after flush\n");
 		goto out;
 	}
 
-	printf("%s with MSG_PEEK_OFF works correctly\n", afstr(af));
+	printf("%s with MSG_PEEK_OFF works correctly\n", afstr(af, proto));
 	res = 1;
 out:
-	if (recv_sock >= 0)
+	if (proto == IPPROTO_TCP && recv_sock >= 0)
 		close(recv_sock);
 	if (s[1] >= 0)
 		close(s[1]);
@@ -160,24 +167,36 @@ static int tcp_peek_offset_test(sa_family_t af)
 	return res;
 }
 
-int main(void)
+static int do_test(int proto)
 {
 	int res4, res6;
 
-	res4 = tcp_peek_offset_probe(AF_INET);
-	res6 = tcp_peek_offset_probe(AF_INET6);
+	res4 = sk_peek_offset_probe(AF_INET, proto);
+	res6 = sk_peek_offset_probe(AF_INET6, proto);
 
 	if (!res4 && !res6)
 		return KSFT_SKIP;
 
 	if (res4)
-		res4 = tcp_peek_offset_test(AF_INET);
+		res4 = sk_peek_offset_test(AF_INET, proto);
 
 	if (res6)
-		res6 = tcp_peek_offset_test(AF_INET6);
+		res6 = sk_peek_offset_test(AF_INET6, proto);
 
 	if (!res4 || !res6)
 		return KSFT_FAIL;
 
 	return KSFT_PASS;
 }
+
+int main(void)
+{
+	int restcp, resudp;
+
+	restcp = do_test(IPPROTO_TCP);
+	resudp = do_test(IPPROTO_UDP);
+	if (restcp == KSFT_FAIL || resudp == KSFT_FAIL)
+		return KSFT_FAIL;
+
+	return KSFT_PASS;
+}