selftests/bpf: Add connect_fd_to_fd, connect_wait net helpers

Add two new network helpers.

connect_fd_to_fd connects an already created client socket fd to address
of server fd. Sometimes it's useful to separate client socket creation
and connecting this socket to a server, e.g. if client socket has to be
created in a cgroup different from that of server cgroup.

Additionally connect_to_fd is now implemented using connect_fd_to_fd,
both helpers don't treat EINPROGRESS as an error and let caller decide
how to proceed with it.

connect_wait is a helper to work with non-blocking client sockets so
that if connect_to_fd or connect_fd_to_fd returned -1 with errno ==
EINPROGRESS, caller can wait for connect to finish or for connection
timeout. The helper returns -1 on error, 0 on timeout (1sec,
hard-coded), and positive number on success.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/1403fab72300f379ca97ead4820ae43eac4414ef.1589486450.git.rdna@fb.com

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 0ff64b7..999a775 100644 (file)
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -4,10 +4,14 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+
+#include <sys/epoll.h>
+
 #include <linux/err.h>
 #include <linux/in.h>
 #include <linux/in6.h>
 
+#include "bpf_util.h"
 #include "network_helpers.h"
 
 #define clean_errno() (errno == 0 ? "None" : strerror(errno))
@@ -77,9 +81,7 @@ static const size_t timeo_optlen = sizeof(timeo_sec);
 
 int connect_to_fd(int family, int type, int server_fd)
 {
-       struct sockaddr_storage addr;
-       socklen_t len = sizeof(addr);
-       int fd;
+       int fd, save_errno;
 
        fd = socket(family, type, 0);
        if (fd < 0) {
@@ -87,24 +89,70 @@ int connect_to_fd(int family, int type, int server_fd)
                return -1;
        }
 
-       if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeo_sec, timeo_optlen)) {
+       if (connect_fd_to_fd(fd, server_fd) < 0 && errno != EINPROGRESS) {
+               save_errno = errno;
+               close(fd);
+               errno = save_errno;
+               return -1;
+       }
+
+       return fd;
+}
+
+int connect_fd_to_fd(int client_fd, int server_fd)
+{
+       struct sockaddr_storage addr;
+       socklen_t len = sizeof(addr);
+       int save_errno;
+
+       if (setsockopt(client_fd, SOL_SOCKET, SO_RCVTIMEO, &timeo_sec,
+                      timeo_optlen)) {
                log_err("Failed to set SO_RCVTIMEO");
-               goto out;
+               return -1;
        }
 
        if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
                log_err("Failed to get server addr");
-               goto out;
+               return -1;
        }
 
-       if (connect(fd, (const struct sockaddr *)&addr, len) < 0) {
-               log_err("Fail to connect to server with family %d", family);
-               goto out;
+       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;
+               }
+               return -1;
        }
 
-       return fd;
+       return 0;
+}
+
+int connect_wait(int fd)
+{
+       struct epoll_event ev = {}, events[2];
+       int timeout_ms = 1000;
+       int efd, nfd;
+
+       efd = epoll_create1(EPOLL_CLOEXEC);
+       if (efd < 0) {
+               log_err("Failed to open epoll fd");
+               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);
+               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);
 
-out:
-       close(fd);
-       return -1;
+       close(efd);
+       return nfd;
 }

diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index a0be7db..86914e6 100644 (file)
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -35,5 +35,7 @@ extern struct ipv6_packet pkt_v6;
 
 int start_server(int family, int type);
 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);
 
 #endif