1 files changed, 274 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/reuseport_addr_any.c b/tools/testing/selftests/net/reuseport_addr_any.c
new file mode 100644
index 000000000000..c6233935fed1
--- /dev/null
+++ b/tools/testing/selftests/net/reuseport_addr_any.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Test that sockets listening on a specific address are preferred
+ * over sockets listening on addr_any.
+ */
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <linux/dccp.h>
+#include <linux/in.h>
+#include <linux/unistd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+static const char *IP4_ADDR = "127.0.0.1";
+static const char *IP6_ADDR = "::1";
+static const char *IP4_MAPPED6 = "::ffff:127.0.0.1";
+
+static const int PORT = 8888;
+
+static void build_rcv_fd(int family, int proto, int *rcv_fds, int count,
+			 const char *addr_str)
+{
+	struct sockaddr_in  addr4 = {0};
+	struct sockaddr_in6 addr6 = {0};
+	struct sockaddr *addr;
+	int opt, i, sz;
+
+	memset(&addr, 0, sizeof(addr));
+
+	switch (family) {
+	case AF_INET:
+		addr4.sin_family = family;
+		if (!addr_str)
+			addr4.sin_addr.s_addr = htonl(INADDR_ANY);
+		else if (!inet_pton(family, addr_str, &addr4.sin_addr.s_addr))
+			error(1, errno, "inet_pton failed: %s", addr_str);
+		addr4.sin_port = htons(PORT);
+		sz = sizeof(addr4);
+		addr = (struct sockaddr *)&addr4;
+		break;
+	case AF_INET6:
+		addr6.sin6_family = AF_INET6;
+		if (!addr_str)
+			addr6.sin6_addr = in6addr_any;
+		else if (!inet_pton(family, addr_str, &addr6.sin6_addr))
+			error(1, errno, "inet_pton failed: %s", addr_str);
+		addr6.sin6_port = htons(PORT);
+		sz = sizeof(addr6);
+		addr = (struct sockaddr *)&addr6;
+		break;
+	default:
+		error(1, 0, "Unsupported family %d", family);
+		/* clang does not recognize error() above as terminating
+		 * the program, so it complains that saddr, sz are
+		 * not initialized when this code path is taken. Silence it.
+		 */
+		return;
+	}
+
+	for (i = 0; i < count; ++i) {
+		rcv_fds[i] = socket(family, proto, 0);
+		if (rcv_fds[i] < 0)
+			error(1, errno, "failed to create receive socket");
+
+		opt = 1;
+		if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
+			       sizeof(opt)))
+			error(1, errno, "failed to set SO_REUSEPORT");
+
+		if (bind(rcv_fds[i], addr, sz))
+			error(1, errno, "failed to bind receive socket");
+
+		if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
+			error(1, errno, "tcp: failed to listen on receive port");
+		else if (proto == SOCK_DCCP) {
+			if (setsockopt(rcv_fds[i], SOL_DCCP,
+					DCCP_SOCKOPT_SERVICE,
+					&(int) {htonl(42)}, sizeof(int)))
+				error(1, errno, "failed to setsockopt");
+
+			if (listen(rcv_fds[i], 10))
+				error(1, errno, "dccp: failed to listen on receive port");
+		}
+	}
+}
+
+static int connect_and_send(int family, int proto)
+{
+	struct sockaddr_in  saddr4 = {0};
+	struct sockaddr_in  daddr4 = {0};
+	struct sockaddr_in6 saddr6 = {0};
+	struct sockaddr_in6 daddr6 = {0};
+	struct sockaddr *saddr, *daddr;
+	int fd, sz;
+
+	switch (family) {
+	case AF_INET:
+		saddr4.sin_family = AF_INET;
+		saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
+		saddr4.sin_port = 0;
+
+		daddr4.sin_family = AF_INET;
+		if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
+			error(1, errno, "inet_pton failed: %s", IP4_ADDR);
+		daddr4.sin_port = htons(PORT);
+
+		sz = sizeof(saddr4);
+		saddr = (struct sockaddr *)&saddr4;
+		daddr = (struct sockaddr *)&daddr4;
+	break;
+	case AF_INET6:
+		saddr6.sin6_family = AF_INET6;
+		saddr6.sin6_addr = in6addr_any;
+
+		daddr6.sin6_family = AF_INET6;
+		if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
+			error(1, errno, "inet_pton failed: %s", IP6_ADDR);
+		daddr6.sin6_port = htons(PORT);
+
+		sz = sizeof(saddr6);
+		saddr = (struct sockaddr *)&saddr6;
+		daddr = (struct sockaddr *)&daddr6;
+	break;
+	default:
+		error(1, 0, "Unsupported family %d", family);
+		/* clang does not recognize error() above as terminating
+		 * the program, so it complains that saddr, daddr, sz are
+		 * not initialized when this code path is taken. Silence it.
+		 */
+		return -1;
+	}
+
+	fd = socket(family, proto, 0);
+	if (fd < 0)
+		error(1, errno, "failed to create send socket");
+
+	if (proto == SOCK_DCCP &&
+		setsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_SERVICE,
+				&(int){htonl(42)}, sizeof(int)))
+		error(1, errno, "failed to setsockopt");
+
+	if (bind(fd, saddr, sz))
+		error(1, errno, "failed to bind send socket");
+
+	if (connect(fd, daddr, sz))
+		error(1, errno, "failed to connect send socket");
+
+	if (send(fd, "a", 1, 0) < 0)
+		error(1, errno, "failed to send message");
+
+	return fd;
+}
+
+static int receive_once(int epfd, int proto)
+{
+	struct epoll_event ev;
+	int i, fd;
+	char buf[8];
+
+	i = epoll_wait(epfd, &ev, 1, 3);
+	if (i < 0)
+		error(1, errno, "epoll_wait failed");
+
+	if (proto == SOCK_STREAM || proto == SOCK_DCCP) {
+		fd = accept(ev.data.fd, NULL, NULL);
+		if (fd < 0)
+			error(1, errno, "failed to accept");
+		i = recv(fd, buf, sizeof(buf), 0);
+		close(fd);
+	} else {
+		i = recv(ev.data.fd, buf, sizeof(buf), 0);
+	}
+
+	if (i < 0)
+		error(1, errno, "failed to recv");
+
+	return ev.data.fd;
+}
+
+static void test(int *rcv_fds, int count, int family, int proto, int fd)
+{
+	struct epoll_event ev;
+	int epfd, i, send_fd, recv_fd;
+
+	epfd = epoll_create(1);
+	if (epfd < 0)
+		error(1, errno, "failed to create epoll");
+
+	ev.events = EPOLLIN;
+	for (i = 0; i < count; ++i) {
+		ev.data.fd = rcv_fds[i];
+		if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
+			error(1, errno, "failed to register sock epoll");
+	}
+
+	send_fd = connect_and_send(family, proto);
+
+	recv_fd = receive_once(epfd, proto);
+	if (recv_fd != fd)
+		error(1, 0, "received on an unexpected socket");
+
+	close(send_fd);
+	close(epfd);
+}
+
+
+static void run_one_test(int fam_send, int fam_rcv, int proto,
+			 const char *addr_str)
+{
+	/* Below we test that a socket listening on a specific address
+	 * is always selected in preference over a socket listening
+	 * on addr_any. Bugs where this is not the case often result
+	 * in sockets created first or last to get picked. So below
+	 * we make sure that there are always addr_any sockets created
+	 * before and after a specific socket is created.
+	 */
+	int rcv_fds[10], i;
+
+	build_rcv_fd(AF_INET, proto, rcv_fds, 2, NULL);
+	build_rcv_fd(AF_INET6, proto, rcv_fds + 2, 2, NULL);
+	build_rcv_fd(fam_rcv, proto, rcv_fds + 4, 1, addr_str);
+	build_rcv_fd(AF_INET, proto, rcv_fds + 5, 2, NULL);
+	build_rcv_fd(AF_INET6, proto, rcv_fds + 7, 2, NULL);
+	test(rcv_fds, 9, fam_send, proto, rcv_fds[4]);
+	for (i = 0; i < 9; ++i)
+		close(rcv_fds[i]);
+	fprintf(stderr, "pass\n");
+}
+
+static void test_proto(int proto, const char *proto_str)
+{
+	if (proto == SOCK_DCCP) {
+		int test_fd;
+
+		test_fd = socket(AF_INET, proto, 0);
+		if (test_fd < 0) {
+			if (errno == ESOCKTNOSUPPORT) {
+				fprintf(stderr, "DCCP not supported: skipping DCCP tests\n");
+				return;
+			} else
+				error(1, errno, "failed to create a DCCP socket");
+		}
+		close(test_fd);
+	}
+
+	fprintf(stderr, "%s IPv4 ... ", proto_str);
+	run_one_test(AF_INET, AF_INET, proto, IP4_ADDR);
+
+	fprintf(stderr, "%s IPv6 ... ", proto_str);
+	run_one_test(AF_INET6, AF_INET6, proto, IP6_ADDR);
+
+	fprintf(stderr, "%s IPv4 mapped to IPv6 ... ", proto_str);
+	run_one_test(AF_INET, AF_INET6, proto, IP4_MAPPED6);
+}
+
+int main(void)
+{
+	test_proto(SOCK_DGRAM, "UDP");
+	test_proto(SOCK_STREAM, "TCP");
+	test_proto(SOCK_DCCP, "DCCP");
+
+	fprintf(stderr, "SUCCESS\n");
+	return 0;
+}