From 8c52800156e22d1a3d06e9f873b68b16ae4035c6 Mon Sep 17 00:00:00 2001
From: Jeff Martin <martinjeffrey@google.com>
Date: Mon, 13 Nov 2023 04:49:21 -0800
Subject: [PATCH] Add a syscall test exercising dualstack address family
 mismatches

Verify that the connect call returns the proper errno when asked to
connect to a remote IP in a different address family than the local IP.

PiperOrigin-RevId: 581919473
---
 test/syscalls/linux/socket_inet_loopback.cc | 37 +++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/test/syscalls/linux/socket_inet_loopback.cc b/test/syscalls/linux/socket_inet_loopback.cc
index 8dde3eeea..bb646ed04 100644
--- a/test/syscalls/linux/socket_inet_loopback.cc
+++ b/test/syscalls/linux/socket_inet_loopback.cc
@@ -20,6 +20,7 @@
 #include <sys/socket.h>
 
 #include <atomic>
+#include <cerrno>
 #include <iostream>
 #include <memory>
 #include <string>
@@ -218,6 +219,42 @@ INSTANTIATE_TEST_SUITE_P(
       return s;
     });
 
+using DualStackAfMismatchTest = ::testing::TestWithParam<ProtocolTestParam>;
+
+TEST_P(DualStackAfMismatchTest, V6ListenerV4Connect) {
+  ProtocolTestParam const& param = GetParam();
+  const FileDescriptor socket_fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, param.type, 0));
+
+  const TestAddress& v6_addr = V6Loopback();
+  const TestAddress& v4_addr = V4MappedLoopback();
+  ASSERT_THAT(
+      bind(socket_fd.get(), AsSockAddr(&v6_addr.addr), v6_addr.addr_len),
+      SyscallSucceeds());
+  ASSERT_THAT(
+      connect(socket_fd.get(), AsSockAddr(&v4_addr.addr), v4_addr.addr_len),
+      SyscallFailsWithErrno(ENETUNREACH));
+}
+
+TEST_P(DualStackAfMismatchTest, V4ListenerV6Connect) {
+  // Gvisor does not return the correct Errno.
+  SKIP_IF(IsRunningOnGvisor());
+  const FileDescriptor socket_fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP));
+
+  const TestAddress& v6_addr = V6Loopback();
+  const TestAddress& v4_addr = V4MappedLoopback();
+  ASSERT_THAT(
+      bind(socket_fd.get(), AsSockAddr(&v4_addr.addr), v4_addr.addr_len),
+      SyscallSucceeds());
+  ASSERT_THAT(
+      connect(socket_fd.get(), AsSockAddr(&v6_addr.addr), v6_addr.addr_len),
+      SyscallFailsWithErrno(EAFNOSUPPORT));
+}
+
+INSTANTIATE_TEST_SUITE_P(All, DualStackAfMismatchTest, ProtocolTestValues(),
+                         DescribeProtocolTestParam);
+
 void tcpSimpleConnectTest(TestAddress const& listener,
                           TestAddress const& connector, bool unbound) {
   // Create the listening socket.