Centralize skip logic

- Inline `IfAddrHelper` into its sole user
- Implement pretty-printing `sockaddr_ll`
- Make test class members private, add const accessors
- Log all interface addresses on SetUp for b/137899561

Simplify some things while I'm here.

PiperOrigin-RevId: 401112402

7 files changed, 98 insertions, 151 deletions

diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 5b882875f..c46ec7a53 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -2670,6 +2670,7 @@ cc_library(
         ":ip_socket_test_util",
         "//test/util:socket_util",
         "//test/util:test_util",
+        "@com_google_absl//absl/cleanup",
     ],
     alwayslink = 1,
 )
diff --git a/test/syscalls/linux/ip_socket_test_util.cc b/test/syscalls/linux/ip_socket_test_util.cc
index a1216d23f..d18e616d0 100644
--- a/test/syscalls/linux/ip_socket_test_util.cc
+++ b/test/syscalls/linux/ip_socket_test_util.cc
@@ -16,6 +16,7 @@
 
 #include <net/if.h>
 #include <netinet/in.h>
+#include <netpacket/packet.h>
 #include <sys/socket.h>
 
 #include <cstring>
@@ -196,75 +197,53 @@ SocketKind IPv6TCPUnboundSocket(int type) {
       UnboundSocketCreator(AF_INET6, type | SOCK_STREAM, IPPROTO_TCP)};
 }
 
-PosixError IfAddrHelper::Load() {
-  Release();
-#ifndef ANDROID
-  RETURN_ERROR_IF_SYSCALL_FAIL(getifaddrs(&ifaddr_));
-#else
-  // Android does not support getifaddrs in r22.
-  return PosixError(ENOSYS, "getifaddrs");
-#endif
-  return NoError();
-}
-
-void IfAddrHelper::Release() {
-  if (ifaddr_) {
-#ifndef ANDROID
-    // Android does not support freeifaddrs in r22.
-    freeifaddrs(ifaddr_);
-#endif
-    ifaddr_ = nullptr;
-  }
-}
-
-std::vector<std::string> IfAddrHelper::InterfaceList(int family) const {
-  std::vector<std::string> names;
-  for (auto ifa = ifaddr_; ifa != NULL; ifa = ifa->ifa_next) {
-    if (ifa->ifa_addr == NULL || ifa->ifa_addr->sa_family != family) {
-      continue;
-    }
-    names.emplace(names.end(), ifa->ifa_name);
-  }
-  return names;
-}
-
-const sockaddr* IfAddrHelper::GetAddr(int family, std::string name) const {
-  for (auto ifa = ifaddr_; ifa != NULL; ifa = ifa->ifa_next) {
-    if (ifa->ifa_addr == NULL || ifa->ifa_addr->sa_family != family) {
-      continue;
-    }
-    if (name == ifa->ifa_name) {
-      return ifa->ifa_addr;
-    }
-  }
-  return nullptr;
-}
-
-PosixErrorOr<int> IfAddrHelper::GetIndex(std::string name) const {
-  return InterfaceIndex(name);
-}
-
 std::string GetAddr4Str(const in_addr* a) {
   char str[INET_ADDRSTRLEN];
-  inet_ntop(AF_INET, a, str, sizeof(str));
-  return std::string(str);
+  return inet_ntop(AF_INET, a, str, sizeof(str));
 }
 
 std::string GetAddr6Str(const in6_addr* a) {
   char str[INET6_ADDRSTRLEN];
-  inet_ntop(AF_INET6, a, str, sizeof(str));
-  return std::string(str);
+  return inet_ntop(AF_INET6, a, str, sizeof(str));
 }
 
 std::string GetAddrStr(const sockaddr* a) {
-  if (a->sa_family == AF_INET) {
-    auto src = &(reinterpret_cast<const sockaddr_in*>(a)->sin_addr);
-    return GetAddr4Str(src);
-  } else if (a->sa_family == AF_INET6) {
-    auto src = &(reinterpret_cast<const sockaddr_in6*>(a)->sin6_addr);
-    return GetAddr6Str(src);
+  switch (a->sa_family) {
+    case AF_INET: {
+      return GetAddr4Str(&(reinterpret_cast<const sockaddr_in*>(a)->sin_addr));
+    }
+    case AF_INET6: {
+      return GetAddr6Str(
+          &(reinterpret_cast<const sockaddr_in6*>(a)->sin6_addr));
+    }
+    case AF_PACKET: {
+      const sockaddr_ll& ll = *reinterpret_cast<const sockaddr_ll*>(a);
+      std::ostringstream ss;
+      ss << std::hex;
+      ss << std::showbase;
+      ss << '{';
+      ss << " protocol=" << ntohs(ll.sll_protocol);
+      ss << " ifindex=" << ll.sll_ifindex;
+      ss << " hatype=" << ll.sll_hatype;
+      ss << " pkttype=" << static_cast<unsigned short>(ll.sll_pkttype);
+      if (ll.sll_halen != 0) {
+        ss << " addr=";
+        for (unsigned char i = 0; i < ll.sll_halen; ++i) {
+          if (i != 0) {
+            ss << ':';
+          }
+          ss << static_cast<unsigned short>(ll.sll_addr[i]);
+        }
+      }
+      ss << " }";
+      return ss.str();
+    }
+    default: {
+      std::ostringstream ss;
+      ss << "invalid(sa_family=" << a->sa_family << ")";
+      return ss.str();
+    }
   }
-  return std::string("<invalid>");
 }
 
 }  // namespace testing
diff --git a/test/syscalls/linux/ip_socket_test_util.h b/test/syscalls/linux/ip_socket_test_util.h
index 556838356..957006e25 100644
--- a/test/syscalls/linux/ip_socket_test_util.h
+++ b/test/syscalls/linux/ip_socket_test_util.h
@@ -115,25 +115,6 @@ SocketKind IPv4TCPUnboundSocket(int type);
 // created with AF_INET6, SOCK_STREAM, IPPROTO_TCP and the given type.
 SocketKind IPv6TCPUnboundSocket(int type);
 
-// IfAddrHelper is a helper class that determines the local interfaces present
-// and provides functions to obtain their names, index numbers, and IP address.
-class IfAddrHelper {
- public:
-  IfAddrHelper() : ifaddr_(nullptr) {}
-  ~IfAddrHelper() { Release(); }
-
-  PosixError Load();
-  void Release();
-
-  std::vector<std::string> InterfaceList(int family) const;
-
-  const sockaddr* GetAddr(int family, std::string name) const;
-  PosixErrorOr<int> GetIndex(std::string name) const;
-
- private:
-  struct ifaddrs* ifaddr_;
-};
-
 // GetAddr4Str returns the given IPv4 network address structure as a string.
 std::string GetAddr4Str(const in_addr* a);
 
diff --git a/test/syscalls/linux/socket_ip_udp_unbound_external_networking.cc b/test/syscalls/linux/socket_ip_udp_unbound_external_networking.cc
index af2459a2f..14da2717b 100644
--- a/test/syscalls/linux/socket_ip_udp_unbound_external_networking.cc
+++ b/test/syscalls/linux/socket_ip_udp_unbound_external_networking.cc
@@ -14,6 +14,7 @@
 
 #include "test/syscalls/linux/socket_ip_udp_unbound_external_networking.h"
 
+#include "absl/cleanup/cleanup.h"
 #include "test/util/socket_util.h"
 #include "test/util/test_util.h"
 
@@ -21,38 +22,50 @@ namespace gvisor {
 namespace testing {
 
 void IPUDPUnboundExternalNetworkingSocketTest::SetUp() {
-  // FIXME(b/137899561): Linux instance for syscall tests sometimes misses its
-  // IPv4 address on eth0.
-  found_net_interfaces_ = false;
-
-  // Get interface list.
-  ASSERT_NO_ERRNO(if_helper_.Load());
-  std::vector<std::string> if_names = if_helper_.InterfaceList(AF_INET);
-  if (if_names.size() != 2) {
-    return;
-  }
+#ifdef ANDROID
+  GTEST_SKIP() << "Android does not support getifaddrs in r22";
+#endif
 
-  // Figure out which interface is where.
-  std::string lo = if_names[0];
-  std::string eth = if_names[1];
-  if (lo != "lo") std::swap(lo, eth);
-  if (lo != "lo") return;
+  ifaddrs* ifaddr;
+  ASSERT_THAT(getifaddrs(&ifaddr), SyscallSucceeds());
+  auto cleanup = absl::MakeCleanup([ifaddr] { freeifaddrs(ifaddr); });
 
-  lo_if_idx_ = ASSERT_NO_ERRNO_AND_VALUE(if_helper_.GetIndex(lo));
-  auto lo_if_addr = if_helper_.GetAddr(AF_INET, lo);
-  if (lo_if_addr == nullptr) {
-    return;
-  }
-  lo_if_addr_ = *reinterpret_cast<const sockaddr_in*>(lo_if_addr);
+  for (const ifaddrs* ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
+    ASSERT_NE(ifa->ifa_name, nullptr);
+    ASSERT_NE(ifa->ifa_addr, nullptr);
+
+    if (ifa->ifa_addr->sa_family != AF_INET) {
+      continue;
+    }
+
+    std::optional<std::pair<int, sockaddr_in>>& if_pair = *[this, ifa]() {
+      if (strcmp(ifa->ifa_name, "lo") == 0) {
+        return &lo_if_;
+      }
+      return &eth_if_;
+    }();
 
-  eth_if_idx_ = ASSERT_NO_ERRNO_AND_VALUE(if_helper_.GetIndex(eth));
-  auto eth_if_addr = if_helper_.GetAddr(AF_INET, eth);
-  if (eth_if_addr == nullptr) {
-    return;
+    const int if_index =
+        ASSERT_NO_ERRNO_AND_VALUE(InterfaceIndex(ifa->ifa_name));
+
+    std::cout << " name=" << ifa->ifa_name
+              << " addr=" << GetAddrStr(ifa->ifa_addr) << " index=" << if_index
+              << " has_value=" << if_pair.has_value() << std::endl;
+
+    if (if_pair.has_value()) {
+      continue;
+    }
+
+    if_pair = std::make_pair(
+        if_index, *reinterpret_cast<const sockaddr_in*>(ifa->ifa_addr));
   }
-  eth_if_addr_ = *reinterpret_cast<const sockaddr_in*>(eth_if_addr);
 
-  found_net_interfaces_ = true;
+  if (!(eth_if_.has_value() && lo_if_.has_value())) {
+    // FIXME(b/137899561): Linux instance for syscall tests sometimes misses its
+    // IPv4 address on eth0.
+    GTEST_SKIP() << " eth_if_.has_value()=" << eth_if_.has_value()
+                 << " lo_if_.has_value()=" << lo_if_.has_value();
+  }
 }
 
 }  // namespace testing
diff --git a/test/syscalls/linux/socket_ip_udp_unbound_external_networking.h b/test/syscalls/linux/socket_ip_udp_unbound_external_networking.h
index 2e8aab129..0387cf8eb 100644
--- a/test/syscalls/linux/socket_ip_udp_unbound_external_networking.h
+++ b/test/syscalls/linux/socket_ip_udp_unbound_external_networking.h
@@ -27,17 +27,16 @@ class IPUDPUnboundExternalNetworkingSocketTest : public SimpleSocketTest {
  protected:
   void SetUp() override;
 
-  IfAddrHelper if_helper_;
+  int lo_if_idx() const { return std::get<0>(lo_if_.value()); }
+  int eth_if_idx() const { return std::get<0>(eth_if_.value()); }
 
-  // found_net_interfaces_ is set to false if SetUp() could not obtain
-  // all interface infos that we need.
-  bool found_net_interfaces_;
+  const sockaddr_in& lo_if_addr() const { return std::get<1>(lo_if_.value()); }
+  const sockaddr_in& eth_if_addr() const {
+    return std::get<1>(eth_if_.value());
+  }
 
-  // Interface infos.
-  int lo_if_idx_;
-  int eth_if_idx_;
-  sockaddr_in lo_if_addr_;
-  sockaddr_in eth_if_addr_;
+ private:
+  std::optional<std::pair<int, sockaddr_in>> lo_if_, eth_if_;
 };
 
 }  // namespace testing
diff --git a/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc b/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
index d440932da..c198c6563 100644
--- a/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
+++ b/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
@@ -28,7 +28,6 @@ TestAddress V4EmptyAddress() {
 // the destination port number.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        UDPBroadcastReceivedOnExpectedPort) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto rcvr1 = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto rcvr2 = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
@@ -101,8 +100,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // not a unicast address.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        UDPBroadcastReceivedOnExpectedAddresses) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto rcvr1 = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto rcvr2 = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
@@ -149,7 +146,7 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
   // Bind the non-receiving socket to the unicast ethernet address.
   auto norecv_addr = rcv1_addr;
   reinterpret_cast<sockaddr_in*>(&norecv_addr.addr)->sin_addr =
-      eth_if_addr_.sin_addr;
+      eth_if_addr().sin_addr;
   ASSERT_THAT(
       bind(norcv->get(), AsSockAddr(&norecv_addr.addr), norecv_addr.addr_len),
       SyscallSucceedsWithValue(0));
@@ -184,7 +181,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 //                     (UDPBroadcastSendRecvOnSocketBoundToAny).
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        UDPBroadcastSendRecvOnSocketBoundToBroadcast) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   // Enable SO_BROADCAST.
@@ -224,7 +220,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 //                     (UDPBroadcastSendRecvOnSocketBoundToBroadcast).
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        UDPBroadcastSendRecvOnSocketBoundToAny) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   // Enable SO_BROADCAST.
@@ -261,7 +256,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // Verifies that a UDP broadcast fails to send on a socket with SO_BROADCAST
 // disabled.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendBroadcast) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   // Broadcast a test message without having enabled SO_BROADCAST on the sending
@@ -306,8 +300,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendUnicastOnUnbound) {
 // set interface or group membership.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastSelfNoGroup) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto socket = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   auto bind_addr = V4Any();
@@ -341,7 +333,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // Check that multicast packets will be delivered to the sending socket without
 // setting an interface.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticastSelf) {
-  SKIP_IF(!found_net_interfaces_);
   auto socket = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   auto bind_addr = V4Any();
@@ -384,7 +375,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticastSelf) {
 // set interface and IP_MULTICAST_LOOP disabled.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastSelfLoopOff) {
-  SKIP_IF(!found_net_interfaces_);
   auto socket = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
   auto bind_addr = V4Any();
@@ -430,8 +420,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // Check that multicast packets won't be delivered to another socket with no
 // set interface or group membership.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticastNoGroup) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
@@ -468,7 +456,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticastNoGroup) {
 // Check that multicast packets will be delivered to another socket without
 // setting an interface.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticast) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
@@ -514,7 +501,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticast) {
 // set interface and IP_MULTICAST_LOOP disabled on the sending socket.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastSenderNoLoop) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
@@ -564,8 +550,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // setting an interface and IP_MULTICAST_LOOP disabled on the receiving socket.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastReceiverNoLoop) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
@@ -616,7 +600,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // and both will receive data on it when bound to the ANY address.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastToTwoBoundToAny) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   std::unique_ptr<FileDescriptor> receivers[2] = {
       ASSERT_NO_ERRNO_AND_VALUE(NewSocket()),
@@ -681,7 +664,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // and both will receive data on it when bound to the multicast address.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastToTwoBoundToMulticastAddress) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   std::unique_ptr<FileDescriptor> receivers[2] = {
       ASSERT_NO_ERRNO_AND_VALUE(NewSocket()),
@@ -749,7 +731,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // multicast address, both will receive data.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        TestSendMulticastToTwoBoundToAnyAndMulticastAddress) {
-  SKIP_IF(!found_net_interfaces_);
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   std::unique_ptr<FileDescriptor> receivers[2] = {
       ASSERT_NO_ERRNO_AND_VALUE(NewSocket()),
@@ -821,8 +802,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // is not a multicast address.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        IpMulticastLoopbackFromAddr) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
 
@@ -885,8 +864,6 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
 // interface, a multicast packet sent out uses the latter as its source address.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        IpMulticastLoopbackIfNicAndAddr) {
-  SKIP_IF(!found_net_interfaces_);
-
   // Create receiver, bind to ANY and join the multicast group.
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver_addr = V4Any();
@@ -902,7 +879,7 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
       reinterpret_cast<sockaddr_in*>(&receiver_addr.addr)->sin_port;
   ip_mreqn group = {};
   group.imr_multiaddr.s_addr = inet_addr(kMulticastAddress);
-  group.imr_ifindex = lo_if_idx_;
+  group.imr_ifindex = lo_if_idx();
   ASSERT_THAT(setsockopt(receiver->get(), IPPROTO_IP, IP_ADD_MEMBERSHIP, &group,
                          sizeof(group)),
               SyscallSucceeds());
@@ -911,8 +888,8 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
   // different interfaces.
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   ip_mreqn iface = {};
-  iface.imr_ifindex = lo_if_idx_;
-  iface.imr_address = eth_if_addr_.sin_addr;
+  iface.imr_ifindex = lo_if_idx();
+  iface.imr_address = eth_if_addr().sin_addr;
   ASSERT_THAT(setsockopt(sender->get(), IPPROTO_IP, IP_MULTICAST_IF, &iface,
                          sizeof(iface)),
               SyscallSucceeds());
@@ -941,15 +918,14 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
   SKIP_IF(IsRunningOnGvisor());
 
   // Verify the received source address.
-  EXPECT_EQ(eth_if_addr_.sin_addr.s_addr, src_addr_in->sin_addr.s_addr);
+  EXPECT_EQ(GetAddr4Str(&eth_if_addr().sin_addr),
+            GetAddr4Str(&src_addr_in->sin_addr));
 }
 
 // Check that when we are bound to one interface we can set IP_MULTICAST_IF to
 // another interface.
 TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
        IpMulticastLoopbackBindToOneIfSetMcastIfToAnother) {
-  SKIP_IF(!found_net_interfaces_);
-
   // FIXME (b/137790511): When bound to one interface it is not possible to set
   // IP_MULTICAST_IF to a different interface.
   SKIP_IF(IsRunningOnGvisor());
@@ -957,7 +933,7 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
   // Create sender and bind to eth interface.
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   ASSERT_THAT(
-      bind(sender->get(), AsSockAddr(&eth_if_addr_), sizeof(eth_if_addr_)),
+      bind(sender->get(), AsSockAddr(&eth_if_addr()), sizeof(eth_if_addr())),
       SyscallSucceeds());
 
   // Run through all possible combinations of index and address for
@@ -966,10 +942,10 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
     int imr_ifindex;
     struct in_addr imr_address;
   } test_data[] = {
-      {lo_if_idx_, {}},
-      {0, lo_if_addr_.sin_addr},
-      {lo_if_idx_, lo_if_addr_.sin_addr},
-      {lo_if_idx_, eth_if_addr_.sin_addr},
+      {lo_if_idx(), {}},
+      {0, lo_if_addr().sin_addr},
+      {lo_if_idx(), lo_if_addr().sin_addr},
+      {lo_if_idx(), eth_if_addr().sin_addr},
   };
   for (auto t : test_data) {
     ip_mreqn iface = {};
diff --git a/test/syscalls/linux/socket_ipv6_udp_unbound_external_networking.cc b/test/syscalls/linux/socket_ipv6_udp_unbound_external_networking.cc
index d72b6b53f..c6e563cd3 100644
--- a/test/syscalls/linux/socket_ipv6_udp_unbound_external_networking.cc
+++ b/test/syscalls/linux/socket_ipv6_udp_unbound_external_networking.cc
@@ -18,8 +18,6 @@ namespace gvisor {
 namespace testing {
 
 TEST_P(IPv6UDPUnboundExternalNetworkingSocketTest, TestJoinLeaveMulticast) {
-  SKIP_IF(!found_net_interfaces_);
-
   auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
   auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());