Fix error code returned due to Port exhaustion.

For TCP sockets gVisor incorrectly returns EAGAIN when no ephemeral ports are
available to bind during a connect. Linux returns EADDRNOTAVAIL. This change
fixes gVisor to return the correct code and adds a test for the same.

This change also fixes a minor bug for ping sockets where connect() would fail
with EINVAL unless the socket was bound first.

Also added tests for testing UDP Port exhaustion and Ping socket port
exhaustion.

PiperOrigin-RevId: 314988525

1 files changed, 91 insertions, 0 deletions

diff --git a/test/syscalls/linux/ping_socket.cc b/test/syscalls/linux/ping_socket.cc
new file mode 100644
index 000000000..a9bfdb37b
--- /dev/null
+++ b/test/syscalls/linux/ping_socket.cc
@@ -0,0 +1,91 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/syscalls/linux/socket_test_util.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/save_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+namespace {
+
+class PingSocket : public ::testing::Test {
+ protected:
+  // Creates a socket to be used in tests.
+  void SetUp() override;
+
+  // Closes the socket created by SetUp().
+  void TearDown() override;
+
+  // The loopback address.
+  struct sockaddr_in addr_;
+};
+
+void PingSocket::SetUp() {
+  // On some hosts ping sockets are restricted to specific groups using the
+  // sysctl "ping_group_range".
+  int s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+  if (s < 0 && errno == EPERM) {
+    GTEST_SKIP();
+  }
+  close(s);
+
+  addr_ = {};
+  // Just a random port as the destination port number is irrelevant for ping
+  // sockets.
+  addr_.sin_port = 12345;
+  addr_.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  addr_.sin_family = AF_INET;
+}
+
+void PingSocket::TearDown() {}
+
+// Test ICMP port exhaustion returns EAGAIN.
+//
+// We disable both random/cooperative S/R for this test as it makes way too many
+// syscalls.
+TEST_F(PingSocket, ICMPPortExhaustion_NoRandomSave) {
+  DisableSave ds;
+  std::vector<FileDescriptor> sockets;
+  constexpr int kSockets = 65536;
+  addr_.sin_port = 0;
+  for (int i = 0; i < kSockets; i++) {
+    auto s =
+        ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP));
+    int ret = connect(s.get(), reinterpret_cast<struct sockaddr*>(&addr_),
+                      sizeof(addr_));
+    if (ret == 0) {
+      sockets.push_back(std::move(s));
+      continue;
+    }
+    ASSERT_THAT(ret, SyscallFailsWithErrno(EAGAIN));
+    break;
+  }
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor