bpf: selftests: A few improvements to network_helpers.c

This patch makes a few changes to the network_helpers.c

1) Enforce SO_RCVTIMEO and SO_SNDTIMEO
   This patch enforces timeout to the network fds through setsockopt
   SO_RCVTIMEO and SO_SNDTIMEO.

   It will remove the need for SOCK_NONBLOCK that requires a more demanding
   timeout logic with epoll/select, e.g. epoll_create, epoll_ctrl, and
   then epoll_wait for timeout.

   That removes the need for connect_wait() from the
   cgroup_skb_sk_lookup.c. The needed change is made in
   cgroup_skb_sk_lookup.c.

2) start_server():
   Add optional addr_str and port to start_server().
   That removes the need of the start_server_with_port().  The caller
   can pass addr_str==NULL and/or port==0.

   I have a future tcp-hdr-opt test that will pass a non-NULL addr_str
   and it is in general useful for other future tests.

   "int timeout_ms" is also added to control the timeout
   on the "accept(listen_fd)".

3) connect_to_fd(): Fully use the server_fd.
   The server sock address has already been obtained from
   getsockname(server_fd).  The sockaddr includes the family,
   so the "int family" arg is redundant.

   Since the server address is obtained from server_fd,  there
   is little reason not to get the server's socket type from the
   server_fd also.  getsockopt(server_fd) can be used to do that,
   so "int type" arg is also removed.

   "int timeout_ms" is added.

4) connect_fd_to_fd():
   "int timeout_ms" is added.
   Some code is also refactored to connect_fd_to_addr() which is
   shared with connect_to_fd().

5) Preserve errno:
   Some callers need to check errno, e.g. cgroup_skb_sk_lookup.c.
   Make changes to do it more consistently in save_errno_close()
   and log_err().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200702004852.2103003-1-kafai@fb.com

tools/testing/selftests/bpf/network_helpers.c

@@ -7,8 +7,6 @@
 
 #include <arpa/inet.h>
 
-#include <sys/epoll.h>
-
 #include <linux/err.h>
 #include <linux/in.h>
 #include <linux/in6.h>
@@ -17,8 +15,13 @@
 #include "network_helpers.h"
 
 #define clean_errno() (errno == 0 ? "None" : strerror(errno))
-#define log_err(MSG, ...) fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
-	__FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
+#define log_err(MSG, ...) ({						\
+			int __save = errno;				\
+			fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
+				__FILE__, __LINE__, clean_errno(),	\
+				##__VA_ARGS__);				\
+			errno = __save;					\
+})
 
 struct ipv4_packet pkt_v4 = {
 	.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
@@ -37,7 +40,34 @@ struct ipv6_packet pkt_v6 = {
 	.tcp.doff = 5,
 };
 
-int start_server_with_port(int family, int type, __u16 port)
+static int settimeo(int fd, int timeout_ms)
+{
+	struct timeval timeout = { .tv_sec = 3 };
+
+	if (timeout_ms > 0) {
+		timeout.tv_sec = timeout_ms / 1000;
+		timeout.tv_usec = (timeout_ms % 1000) * 1000;
+	}
+
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout,
+		       sizeof(timeout))) {
+		log_err("Failed to set SO_RCVTIMEO");
+		return -1;
+	}
+
+	if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeout,
+		       sizeof(timeout))) {
+		log_err("Failed to set SO_SNDTIMEO");
+		return -1;
+	}
+
+	return 0;
+}
+
+#define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })
+
+int start_server(int family, int type, const char *addr_str, __u16 port,
+		 int timeout_ms)
 {
 	struct sockaddr_storage addr = {};
 	socklen_t len;
@@ -48,120 +78,119 @@ int start_server_with_port(int family, int type, __u16 port)
 
 		sin->sin_family = AF_INET;
 		sin->sin_port = htons(port);
+		if (addr_str &&
+		    inet_pton(AF_INET, addr_str, &sin->sin_addr) != 1) {
+			log_err("inet_pton(AF_INET, %s)", addr_str);
+			return -1;
+		}
 		len = sizeof(*sin);
 	} else {
 		struct sockaddr_in6 *sin6 = (void *)&addr;
 
 		sin6->sin6_family = AF_INET6;
 		sin6->sin6_port = htons(port);
+		if (addr_str &&
+		    inet_pton(AF_INET6, addr_str, &sin6->sin6_addr) != 1) {
+			log_err("inet_pton(AF_INET6, %s)", addr_str);
+			return -1;
+		}
 		len = sizeof(*sin6);
 	}
 
-	fd = socket(family, type | SOCK_NONBLOCK, 0);
+	fd = socket(family, type, 0);
 	if (fd < 0) {
 		log_err("Failed to create server socket");
 		return -1;
 	}
 
+	if (settimeo(fd, timeout_ms))
+		goto error_close;
+
 	if (bind(fd, (const struct sockaddr *)&addr, len) < 0) {
 		log_err("Failed to bind socket");
-		close(fd);
-		return -1;
+		goto error_close;
 	}
 
 	if (type == SOCK_STREAM) {
 		if (listen(fd, 1) < 0) {
 			log_err("Failed to listed on socket");
-			close(fd);
-			return -1;
+			goto error_close;
 		}
 	}
 
 	return fd;
-}
 
-int start_server(int family, int type)
-{
-	return start_server_with_port(family, type, 0);
+error_close:
+	save_errno_close(fd);
+	return -1;
 }
 
-static const struct timeval timeo_sec = { .tv_sec = 3 };
-static const size_t timeo_optlen = sizeof(timeo_sec);
-
-int connect_to_fd(int family, int type, int server_fd)
+static int connect_fd_to_addr(int fd,
+			      const struct sockaddr_storage *addr,
+			      socklen_t addrlen)
 {
-	int fd, save_errno;
-
-	fd = socket(family, type, 0);
-	if (fd < 0) {
-		log_err("Failed to create client socket");
+	if (connect(fd, (const struct sockaddr *)addr, addrlen)) {
+		log_err("Failed to connect to server");
 		return -1;
 	}
 
-	if (connect_fd_to_fd(fd, server_fd) < 0 && errno != EINPROGRESS) {
-		save_errno = errno;
-		close(fd);
-		errno = save_errno;
-		return -1;
-	}
-
-	return fd;
+	return 0;
 }
 
-int connect_fd_to_fd(int client_fd, int server_fd)
+int connect_to_fd(int server_fd, int timeout_ms)
 {
 	struct sockaddr_storage addr;
-	socklen_t len = sizeof(addr);
-	int save_errno;
+	struct sockaddr_in *addr_in;
+	socklen_t addrlen, optlen;
+	int fd, type;
 
-	if (setsockopt(client_fd, SOL_SOCKET, SO_RCVTIMEO, &timeo_sec,
-		       timeo_optlen)) {
-		log_err("Failed to set SO_RCVTIMEO");
+	optlen = sizeof(type);
+	if (getsockopt(server_fd, SOL_SOCKET, SO_TYPE, &type, &optlen)) {
+		log_err("getsockopt(SOL_TYPE)");
 		return -1;
 	}
 
-	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
+	addrlen = sizeof(addr);
+	if (getsockname(server_fd, (struct sockaddr *)&addr, &addrlen)) {
 		log_err("Failed to get server addr");
 		return -1;
 	}
 
-	if (connect(client_fd, (const struct sockaddr *)&addr, len) < 0) {
-		if (errno != EINPROGRESS) {
-			save_errno = errno;
-			log_err("Failed to connect to server");
-			errno = save_errno;
-		}
+	addr_in = (struct sockaddr_in *)&addr;
+	fd = socket(addr_in->sin_family, type, 0);
+	if (fd < 0) {
+		log_err("Failed to create client socket");
 		return -1;
 	}
 
-	return 0;
+	if (settimeo(fd, timeout_ms))
+		goto error_close;
+
+	if (connect_fd_to_addr(fd, &addr, addrlen))
+		goto error_close;
+
+	return fd;
+
+error_close:
+	save_errno_close(fd);
+	return -1;
 }
 
-int connect_wait(int fd)
+int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms)
 {
-	struct epoll_event ev = {}, events[2];
-	int timeout_ms = 1000;
-	int efd, nfd;
+	struct sockaddr_storage addr;
+	socklen_t len = sizeof(addr);
 
-	efd = epoll_create1(EPOLL_CLOEXEC);
-	if (efd < 0) {
-		log_err("Failed to open epoll fd");
+	if (settimeo(client_fd, timeout_ms))
 		return -1;
-	}
-
-	ev.events = EPOLLRDHUP | EPOLLOUT;
-	ev.data.fd = fd;
 
-	if (epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ev) < 0) {
-		log_err("Failed to register fd=%d on epoll fd=%d", fd, efd);
-		close(efd);
+	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
+		log_err("Failed to get server addr");
 		return -1;
 	}
 
-	nfd = epoll_wait(efd, events, ARRAY_SIZE(events), timeout_ms);
-	if (nfd < 0)
-		log_err("Failed to wait for I/O event on epoll fd=%d", efd);
+	if (connect_fd_to_addr(client_fd, &addr, len))
+		return -1;
 
-	close(efd);
-	return nfd;
+	return 0;
 }

tools/testing/selftests/bpf/network_helpers.h

@@ -33,10 +33,9 @@ struct ipv6_packet {
 } __packed;
 extern struct ipv6_packet pkt_v6;
 
-int start_server(int family, int type);
-int start_server_with_port(int family, int type, __u16 port);
-int connect_to_fd(int family, int type, int server_fd);
-int connect_fd_to_fd(int client_fd, int server_fd);
-int connect_wait(int client_fd);
+int start_server(int family, int type, const char *addr, __u16 port,
+		 int timeout_ms);
+int connect_to_fd(int server_fd, int timeout_ms);
+int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms);
 
 #endif

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

@@ -13,7 +13,7 @@ static void run_lookup_test(__u16 *g_serv_port, int out_sk)
 	socklen_t addr_len = sizeof(addr);
 	__u32 duration = 0;
 
-	serv_sk = start_server(AF_INET6, SOCK_STREAM);
+	serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
 	if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))
 		return;
 
@@ -24,17 +24,13 @@ static void run_lookup_test(__u16 *g_serv_port, int out_sk)
 	*g_serv_port = addr.sin6_port;
 
 	/* Client outside of test cgroup should fail to connect by timeout. */
-	err = connect_fd_to_fd(out_sk, serv_sk);
+	err = connect_fd_to_fd(out_sk, serv_sk, 1000);
 	if (CHECK(!err || errno != EINPROGRESS, "connect_fd_to_fd",
 		  "unexpected result err %d errno %d\n", err, errno))
 		goto cleanup;
 
-	err = connect_wait(out_sk);
-	if (CHECK(err, "connect_wait", "unexpected result %d\n", err))
-		goto cleanup;
-
 	/* Client inside test cgroup should connect just fine. */
-	in_sk = connect_to_fd(AF_INET6, SOCK_STREAM, serv_sk);
+	in_sk = connect_to_fd(serv_sk, 0);
 	if (CHECK(in_sk < 0, "connect_to_fd", "errno %d\n", errno))
 		goto cleanup;
 
@@ -85,7 +81,7 @@ void test_cgroup_skb_sk_lookup(void)
 	 * differs from that of testing cgroup. Moving selftests process to
 	 * testing cgroup won't change cgroup id of an already created socket.
 	 */
-	out_sk = socket(AF_INET6, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	out_sk = socket(AF_INET6, SOCK_STREAM, 0);
 	if (CHECK_FAIL(out_sk < 0))
 		return;
 

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

@@ -114,7 +114,7 @@ static int run_test(int cgroup_fd, int server_fd, int family, int type)
 		goto close_bpf_object;
 	}
 
-	fd = connect_to_fd(family, type, server_fd);
+	fd = connect_to_fd(server_fd, 0);
 	if (fd < 0) {
 		err = -1;
 		goto close_bpf_object;
@@ -137,25 +137,25 @@ void test_connect_force_port(void)
 	if (CHECK_FAIL(cgroup_fd < 0))
 		return;
 
-	server_fd = start_server_with_port(AF_INET, SOCK_STREAM, 60123);
+	server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 60123, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET, SOCK_STREAM));
 	close(server_fd);
 
-	server_fd = start_server_with_port(AF_INET6, SOCK_STREAM, 60124);
+	server_fd = start_server(AF_INET6, SOCK_STREAM, NULL, 60124, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET6, SOCK_STREAM));
 	close(server_fd);
 
-	server_fd = start_server_with_port(AF_INET, SOCK_DGRAM, 60123);
+	server_fd = start_server(AF_INET, SOCK_DGRAM, NULL, 60123, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET, SOCK_DGRAM));
 	close(server_fd);
 
-	server_fd = start_server_with_port(AF_INET6, SOCK_DGRAM, 60124);
+	server_fd = start_server(AF_INET6, SOCK_DGRAM, NULL, 60124, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET6, SOCK_DGRAM));

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

@@ -23,7 +23,7 @@ void test_load_bytes_relative(void)
 	if (CHECK_FAIL(cgroup_fd < 0))
 		return;
 
-	server_fd = start_server(AF_INET, SOCK_STREAM);
+	server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
 
@@ -49,7 +49,7 @@ void test_load_bytes_relative(void)
 	if (CHECK_FAIL(err))
 		goto close_bpf_object;
 
-	client_fd = connect_to_fd(AF_INET, SOCK_STREAM, server_fd);
+	client_fd = connect_to_fd(server_fd, 0);
 	if (CHECK_FAIL(client_fd < 0))
 		goto close_bpf_object;
 	close(client_fd);

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

@@ -118,7 +118,7 @@ static int run_test(int cgroup_fd, int server_fd)
 		goto close_bpf_object;
 	}
 
-	client_fd = connect_to_fd(AF_INET, SOCK_STREAM, server_fd);
+	client_fd = connect_to_fd(server_fd, 0);
 	if (client_fd < 0) {
 		err = -1;
 		goto close_bpf_object;
@@ -161,7 +161,7 @@ void test_tcp_rtt(void)
 	if (CHECK_FAIL(cgroup_fd < 0))
 		return;
 
-	server_fd = start_server(AF_INET, SOCK_STREAM);
+	server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;