tests/ifaddrs_test.cpp - platform/bionic - Git at Google

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * 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 <gtest/gtest.h>

 #include <ifaddrs.h>

 #include <dirent.h>
 #include <linux/if_packet.h>
 #include <net/ethernet.h>
 #include <net/if.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <sys/ioctl.h>

 #include <algorithm>
 #include <map>
 #include <vector>

 TEST(ifaddrs, freeifaddrs_null) {
   freeifaddrs(nullptr);
 }

 // We can't statically say much about what network interfaces are available, but we can be pretty
 // sure there's a loopback interface, and that it has IPv4, IPv6, and AF_PACKET entries.
 TEST(ifaddrs, getifaddrs_lo) {
   ifaddrs* addrs = nullptr;

   ASSERT_EQ(0, getifaddrs(&addrs));
   ASSERT_TRUE(addrs != nullptr);

   ifaddrs* lo_inet4 = nullptr;
   ifaddrs* lo_inet6 = nullptr;
   ifaddrs* lo_packet = nullptr;
   for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
     if (addr->ifa_name && strcmp(addr->ifa_name, "lo") == 0) {
       if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET) lo_inet4 = addr;
       else if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET6) lo_inet6 = addr;
       else if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_PACKET) lo_packet = addr;
     }
   }

   // Does the IPv4 entry look right?
   ASSERT_TRUE(lo_inet4 != nullptr);
   const sockaddr_in* sa_inet4 = reinterpret_cast<const sockaddr_in*>(lo_inet4->ifa_addr);
   ASSERT_TRUE(ntohl(sa_inet4->sin_addr.s_addr) == INADDR_LOOPBACK);

   // Does the IPv6 entry look right?
   ASSERT_TRUE(lo_inet6 != nullptr);
   const sockaddr_in6* sa_inet6 = reinterpret_cast<const sockaddr_in6*>(lo_inet6->ifa_addr);
   ASSERT_TRUE(IN6_IS_ADDR_LOOPBACK(&sa_inet6->sin6_addr));

   // Does the AF_PACKET entry look right?
   ASSERT_TRUE(lo_packet != nullptr);
   const sockaddr_ll* sa_ll = reinterpret_cast<const sockaddr_ll*>(lo_packet->ifa_addr);
   ASSERT_EQ(6, sa_ll->sll_halen);

   freeifaddrs(addrs);
 }

 // Check that getifaddrs sees the same list of interfaces as /sys/class/net.
 TEST(ifaddrs, getifaddrs_interfaces) {
   std::vector<std::string> ifaddrs_socks;
   {
     ifaddrs* addrs;
     ASSERT_EQ(0, getifaddrs(&addrs));

     for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
       int family = addr->ifa_addr ? addr->ifa_addr->sa_family :
           addr->ifa_broadaddr ? addr->ifa_broadaddr->sa_family :
           AF_UNSPEC;

       if (family == AF_PACKET || family == AF_UNSPEC) {
         ifaddrs_socks.push_back(std::string(addr->ifa_name));
       }
     }

     freeifaddrs(addrs);
   }

   std::vector<std::string> sys_class_net;
   {
     std::unique_ptr<DIR, decltype(&closedir)> d(opendir("/sys/class/net"), closedir);
     ASSERT_TRUE(d != nullptr);
     dirent* dir;
     while ((dir = readdir(d.get())) != nullptr) {
       if (dir->d_type == DT_LNK) {
         sys_class_net.push_back(std::string(dir->d_name));
       }
     }
   }

   ASSERT_TRUE(std::is_permutation(ifaddrs_socks.begin(), ifaddrs_socks.end(),
                                   sys_class_net.begin()));
 }

 static void CheckAddressIsInSet(const std::string& if_name, bool unicast,
                                 const std::set<in_addr_t>& addrs) {
   ifreq ifr;
   memset(&ifr, 0, sizeof(ifr));
   ifr.ifr_addr.sa_family = AF_INET;
   if_name.copy(ifr.ifr_name, IFNAMSIZ - 1);

   int fd = socket(AF_INET, SOCK_DGRAM, 0);
   ASSERT_TRUE(fd != -1);

   int request = SIOCGIFADDR;
   if (!unicast) {
     // For non-unicast, the specific ioctl to use depends on whether the IFF_BROADCAST flag is set.
     ASSERT_EQ(0, ioctl(fd, SIOCGIFFLAGS, &ifr)) << if_name << ' ' << strerror(errno);
     request = ((ifr.ifr_flags & IFF_BROADCAST) != 0) ? SIOCGIFBRDADDR : SIOCGIFDSTADDR;
   }

   ASSERT_EQ(0, ioctl(fd, request, &ifr)) << if_name << ' ' << strerror(errno);
   close(fd);

   sockaddr_in* sock = reinterpret_cast<sockaddr_in*>(&ifr.ifr_addr);
   in_addr_t addr = sock->sin_addr.s_addr;

   EXPECT_TRUE(addrs.find(addr) != addrs.end()) << if_name << ' ' << std::hex << ntohl(addr);
 }

 TEST(ifaddrs, getifaddrs_INET) {
   std::map<std::string, std::set<in_addr_t>> inet_addrs;
   std::map<std::string, std::set<in_addr_t>> broad_addrs;

   // Collect the IPv4 addresses for each interface.
   ifaddrs* addrs;
   ASSERT_EQ(0, getifaddrs(&addrs));
   for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
     if (addr->ifa_name && addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET) {
       auto sock = reinterpret_cast<sockaddr_in*>(addr->ifa_addr);
       inet_addrs[addr->ifa_name].insert(sock->sin_addr.s_addr);
     }
     if (addr->ifa_name && addr->ifa_broadaddr && addr->ifa_broadaddr->sa_family == AF_INET) {
       auto sock = reinterpret_cast<sockaddr_in*>(addr->ifa_broadaddr);
       broad_addrs[addr->ifa_name].insert(sock->sin_addr.s_addr);
     }
   }
   freeifaddrs(addrs);

   // Check that the addresses returned by the SIOCGIFADDR and SIOCGIFBRDADDR/SIOCGIFDSTADDR ioctls
   // are in our collections.
   for (const auto& it : inet_addrs) CheckAddressIsInSet(it.first, true, it.second);
   for (const auto& it : broad_addrs) CheckAddressIsInSet(it.first, false, it.second);
 }

 static void print_sockaddr_ll(const char* what, const sockaddr* p) {
   const sockaddr_ll* s = reinterpret_cast<const sockaddr_ll*>(p);
   printf("\t\t%s\t", what);
   for (int i = 0; i < s->sll_halen; ++i) {
     if (i > 0) printf(":");
     printf("%02X", s->sll_addr[i]);
   }
   printf(" (%d bytes)\n", s->sll_halen);
 }

 static void print_sockaddr_inet(const char* what, const sockaddr* addr) {
   char host[NI_MAXHOST];
   int family = addr->sa_family;
   int error = getnameinfo(addr,
                           (family == AF_INET) ? sizeof(sockaddr_in) : sizeof(sockaddr_in6),
                           host, NI_MAXHOST, nullptr, 0, NI_NUMERICHOST);
   if (error != 0) {
     printf("%d getnameinfo() failed: %s\n", family, gai_strerror(error));
     strcpy(host, "???");
   }
   printf("\t\t%s: <%s>\n", what, host);
 }

 static const char* FamilyToName(int family) {
   if (family == AF_INET) return "AF_INET";
   if (family == AF_INET6) return "AF_INET6";
   if (family == AF_PACKET) return "AF_PACKET";
   if (family == AF_UNSPEC) return "AF_UNSPEC";
   return "?";
 }

 static std::string FlagsToString(short flags) {
   std::string result;
   if ((flags & IFF_UP) != 0) result += " UP";
   if ((flags & IFF_BROADCAST) != 0) result += " BROADCAST";
   if ((flags & IFF_DEBUG) != 0) result += " DEBUG";
   if ((flags & IFF_LOOPBACK) != 0) result += " LOOPBACK";
   if ((flags & IFF_POINTOPOINT) != 0) result += " POINTOPOINT";
   if ((flags & IFF_NOTRAILERS) != 0) result += " NOTRAILERS";
   if ((flags & IFF_RUNNING) != 0) result += " RUNNING";
   if ((flags & IFF_NOARP) != 0) result += " NOARP";
   if ((flags & IFF_PROMISC) != 0) result += " PROMISC";
   if ((flags & IFF_ALLMULTI) != 0) result += " ALLMULTI";
   if ((flags & IFF_MASTER) != 0) result += " MASTER";
   if ((flags & IFF_SLAVE) != 0) result += " SLAVE";
   if ((flags & IFF_MULTICAST) != 0) result += " MULTICAST";
   if ((flags & IFF_PORTSEL) != 0) result += " PORTSEL";
   if ((flags & IFF_AUTOMEDIA) != 0) result += " AUTOMEDIA";
   if ((flags & IFF_DYNAMIC) != 0) result += " DYNAMIC";
 #if defined(IFF_LOWER_UP)
   if ((flags & IFF_LOWER_UP) != 0) result += " LOWER_UP";
 #endif
 #if defined(IFF_DORMANT)
   if ((flags & IFF_DORMANT) != 0) result += " DORMANT";
 #endif
 #if defined(IFF_ECHO)
   if ((flags & IFF_ECHO) != 0) result += " ECHO";
 #endif
   return result;
 }

 // Not really a test, but a useful debugging tool.
 TEST(ifaddrs, dump) {
   ifaddrs* addrs;
   ASSERT_EQ(0, getifaddrs(&addrs));

   for (ifaddrs* ifa = addrs; ifa != nullptr; ifa = ifa->ifa_next) {
     int family = ifa->ifa_addr ? ifa->ifa_addr->sa_family :
                                  ifa->ifa_broadaddr ? ifa->ifa_broadaddr->sa_family : AF_UNSPEC;

     printf("\t%s\n"
            "\t\t%s (%d) flags=%#x%s\n",
            ifa->ifa_name, FamilyToName(family), family,
            ifa->ifa_flags, FlagsToString(ifa->ifa_flags).c_str());

     if (family == AF_PACKET) {
       if (ifa->ifa_addr) print_sockaddr_ll("hwaddr", ifa->ifa_addr);
       if (ifa->ifa_broadaddr) print_sockaddr_ll("hwbroad", ifa->ifa_addr);
     } else if (family == AF_INET || family == AF_INET6) {
       if (ifa->ifa_addr) print_sockaddr_inet("address", ifa->ifa_addr);
       if (ifa->ifa_broadaddr && (ifa->ifa_flags & (IFF_BROADCAST | IFF_POINTOPOINT)) != 0) {
         print_sockaddr_inet((ifa->ifa_flags & IFF_BROADCAST) ? "broadcast" : "destination",
                             ifa->ifa_broadaddr);
       }
     }

     fflush(stdout);
   }

   freeifaddrs(addrs);
 }

 TEST(ifaddrs, inet6_scope_ids) {
   ifaddrs* addrs;
   ASSERT_EQ(0, getifaddrs(&addrs));

   for (ifaddrs* ifa = addrs; ifa != nullptr; ifa = ifa->ifa_next) {
     if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6) {
       sockaddr_in6* sa6 = reinterpret_cast<sockaddr_in6*>(ifa->ifa_addr);
       // Any link-local IPv6 address should have a scope id. (http://b/27219454.)
       // 0 isn't a valid interface index, so that would mean the scope id wasn't set.
       if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr) || IN6_IS_ADDR_MC_LINKLOCAL(&sa6->sin6_addr)) {
         ASSERT_NE(sa6->sin6_scope_id, 0U);
       }
     }
   }

   freeifaddrs(addrs);
 }
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* 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 <gtest/gtest.h>

	#include <ifaddrs.h>

	#include <dirent.h>
	#include <linux/if_packet.h>
	#include <net/ethernet.h>
	#include <net/if.h>
	#include <netdb.h>
	#include <netinet/in.h>
	#include <sys/ioctl.h>

	#include <algorithm>
	#include <map>
	#include <vector>

	TEST(ifaddrs, freeifaddrs_null) {
	freeifaddrs(nullptr);
	}

	// We can't statically say much about what network interfaces are available, but we can be pretty
	// sure there's a loopback interface, and that it has IPv4, IPv6, and AF_PACKET entries.
	TEST(ifaddrs, getifaddrs_lo) {
	ifaddrs* addrs = nullptr;

	ASSERT_EQ(0, getifaddrs(&addrs));
	ASSERT_TRUE(addrs != nullptr);

	ifaddrs* lo_inet4 = nullptr;
	ifaddrs* lo_inet6 = nullptr;
	ifaddrs* lo_packet = nullptr;
	for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
	if (addr->ifa_name && strcmp(addr->ifa_name, "lo") == 0) {
	if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET) lo_inet4 = addr;
	else if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET6) lo_inet6 = addr;
	else if (addr->ifa_addr && addr->ifa_addr->sa_family == AF_PACKET) lo_packet = addr;
	}
	}

	// Does the IPv4 entry look right?
	ASSERT_TRUE(lo_inet4 != nullptr);
	const sockaddr_in* sa_inet4 = reinterpret_cast<const sockaddr_in*>(lo_inet4->ifa_addr);
	ASSERT_TRUE(ntohl(sa_inet4->sin_addr.s_addr) == INADDR_LOOPBACK);

	// Does the IPv6 entry look right?
	ASSERT_TRUE(lo_inet6 != nullptr);
	const sockaddr_in6* sa_inet6 = reinterpret_cast<const sockaddr_in6*>(lo_inet6->ifa_addr);
	ASSERT_TRUE(IN6_IS_ADDR_LOOPBACK(&sa_inet6->sin6_addr));

	// Does the AF_PACKET entry look right?
	ASSERT_TRUE(lo_packet != nullptr);
	const sockaddr_ll* sa_ll = reinterpret_cast<const sockaddr_ll*>(lo_packet->ifa_addr);
	ASSERT_EQ(6, sa_ll->sll_halen);

	freeifaddrs(addrs);
	}

	// Check that getifaddrs sees the same list of interfaces as /sys/class/net.
	TEST(ifaddrs, getifaddrs_interfaces) {
	std::vector<std::string> ifaddrs_socks;
	{
	ifaddrs* addrs;
	ASSERT_EQ(0, getifaddrs(&addrs));

	for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
	int family = addr->ifa_addr ? addr->ifa_addr->sa_family :
	addr->ifa_broadaddr ? addr->ifa_broadaddr->sa_family :
	AF_UNSPEC;

	if (family == AF_PACKET \|\| family == AF_UNSPEC) {
	ifaddrs_socks.push_back(std::string(addr->ifa_name));
	}
	}

	freeifaddrs(addrs);
	}

	std::vector<std::string> sys_class_net;
	{
	std::unique_ptr<DIR, decltype(&closedir)> d(opendir("/sys/class/net"), closedir);
	ASSERT_TRUE(d != nullptr);
	dirent* dir;
	while ((dir = readdir(d.get())) != nullptr) {
	if (dir->d_type == DT_LNK) {
	sys_class_net.push_back(std::string(dir->d_name));
	}
	}
	}

	ASSERT_TRUE(std::is_permutation(ifaddrs_socks.begin(), ifaddrs_socks.end(),
	sys_class_net.begin()));
	}

	static void CheckAddressIsInSet(const std::string& if_name, bool unicast,
	const std::set<in_addr_t>& addrs) {
	ifreq ifr;
	memset(&ifr, 0, sizeof(ifr));
	ifr.ifr_addr.sa_family = AF_INET;
	if_name.copy(ifr.ifr_name, IFNAMSIZ - 1);

	int fd = socket(AF_INET, SOCK_DGRAM, 0);
	ASSERT_TRUE(fd != -1);

	int request = SIOCGIFADDR;
	if (!unicast) {
	// For non-unicast, the specific ioctl to use depends on whether the IFF_BROADCAST flag is set.
	ASSERT_EQ(0, ioctl(fd, SIOCGIFFLAGS, &ifr)) << if_name << ' ' << strerror(errno);
	request = ((ifr.ifr_flags & IFF_BROADCAST) != 0) ? SIOCGIFBRDADDR : SIOCGIFDSTADDR;
	}

	ASSERT_EQ(0, ioctl(fd, request, &ifr)) << if_name << ' ' << strerror(errno);
	close(fd);

	sockaddr_in* sock = reinterpret_cast<sockaddr_in*>(&ifr.ifr_addr);
	in_addr_t addr = sock->sin_addr.s_addr;

	EXPECT_TRUE(addrs.find(addr) != addrs.end()) << if_name << ' ' << std::hex << ntohl(addr);
	}

	TEST(ifaddrs, getifaddrs_INET) {
	std::map<std::string, std::set<in_addr_t>> inet_addrs;
	std::map<std::string, std::set<in_addr_t>> broad_addrs;

	// Collect the IPv4 addresses for each interface.
	ifaddrs* addrs;
	ASSERT_EQ(0, getifaddrs(&addrs));
	for (ifaddrs* addr = addrs; addr != nullptr; addr = addr->ifa_next) {
	if (addr->ifa_name && addr->ifa_addr && addr->ifa_addr->sa_family == AF_INET) {
	auto sock = reinterpret_cast<sockaddr_in*>(addr->ifa_addr);
	inet_addrs[addr->ifa_name].insert(sock->sin_addr.s_addr);
	}
	if (addr->ifa_name && addr->ifa_broadaddr && addr->ifa_broadaddr->sa_family == AF_INET) {
	auto sock = reinterpret_cast<sockaddr_in*>(addr->ifa_broadaddr);
	broad_addrs[addr->ifa_name].insert(sock->sin_addr.s_addr);
	}
	}
	freeifaddrs(addrs);

	// Check that the addresses returned by the SIOCGIFADDR and SIOCGIFBRDADDR/SIOCGIFDSTADDR ioctls
	// are in our collections.
	for (const auto& it : inet_addrs) CheckAddressIsInSet(it.first, true, it.second);
	for (const auto& it : broad_addrs) CheckAddressIsInSet(it.first, false, it.second);
	}

	static void print_sockaddr_ll(const char* what, const sockaddr* p) {
	const sockaddr_ll* s = reinterpret_cast<const sockaddr_ll*>(p);
	printf("\t\t%s\t", what);
	for (int i = 0; i < s->sll_halen; ++i) {
	if (i > 0) printf(":");
	printf("%02X", s->sll_addr[i]);
	}
	printf(" (%d bytes)\n", s->sll_halen);
	}

	static void print_sockaddr_inet(const char* what, const sockaddr* addr) {
	char host[NI_MAXHOST];
	int family = addr->sa_family;
	int error = getnameinfo(addr,
	(family == AF_INET) ? sizeof(sockaddr_in) : sizeof(sockaddr_in6),
	host, NI_MAXHOST, nullptr, 0, NI_NUMERICHOST);
	if (error != 0) {
	printf("%d getnameinfo() failed: %s\n", family, gai_strerror(error));
	strcpy(host, "???");
	}
	printf("\t\t%s: <%s>\n", what, host);
	}

	static const char* FamilyToName(int family) {
	if (family == AF_INET) return "AF_INET";
	if (family == AF_INET6) return "AF_INET6";
	if (family == AF_PACKET) return "AF_PACKET";
	if (family == AF_UNSPEC) return "AF_UNSPEC";
	return "?";
	}

	static std::string FlagsToString(short flags) {
	std::string result;
	if ((flags & IFF_UP) != 0) result += " UP";
	if ((flags & IFF_BROADCAST) != 0) result += " BROADCAST";
	if ((flags & IFF_DEBUG) != 0) result += " DEBUG";
	if ((flags & IFF_LOOPBACK) != 0) result += " LOOPBACK";
	if ((flags & IFF_POINTOPOINT) != 0) result += " POINTOPOINT";
	if ((flags & IFF_NOTRAILERS) != 0) result += " NOTRAILERS";
	if ((flags & IFF_RUNNING) != 0) result += " RUNNING";
	if ((flags & IFF_NOARP) != 0) result += " NOARP";
	if ((flags & IFF_PROMISC) != 0) result += " PROMISC";
	if ((flags & IFF_ALLMULTI) != 0) result += " ALLMULTI";
	if ((flags & IFF_MASTER) != 0) result += " MASTER";
	if ((flags & IFF_SLAVE) != 0) result += " SLAVE";
	if ((flags & IFF_MULTICAST) != 0) result += " MULTICAST";
	if ((flags & IFF_PORTSEL) != 0) result += " PORTSEL";
	if ((flags & IFF_AUTOMEDIA) != 0) result += " AUTOMEDIA";
	if ((flags & IFF_DYNAMIC) != 0) result += " DYNAMIC";
	#if defined(IFF_LOWER_UP)
	if ((flags & IFF_LOWER_UP) != 0) result += " LOWER_UP";
	#endif
	#if defined(IFF_DORMANT)
	if ((flags & IFF_DORMANT) != 0) result += " DORMANT";
	#endif
	#if defined(IFF_ECHO)
	if ((flags & IFF_ECHO) != 0) result += " ECHO";
	#endif
	return result;
	}

	// Not really a test, but a useful debugging tool.
	TEST(ifaddrs, dump) {
	ifaddrs* addrs;
	ASSERT_EQ(0, getifaddrs(&addrs));

	for (ifaddrs* ifa = addrs; ifa != nullptr; ifa = ifa->ifa_next) {
	int family = ifa->ifa_addr ? ifa->ifa_addr->sa_family :
	ifa->ifa_broadaddr ? ifa->ifa_broadaddr->sa_family : AF_UNSPEC;

	printf("\t%s\n"
	"\t\t%s (%d) flags=%#x%s\n",
	ifa->ifa_name, FamilyToName(family), family,
	ifa->ifa_flags, FlagsToString(ifa->ifa_flags).c_str());

	if (family == AF_PACKET) {
	if (ifa->ifa_addr) print_sockaddr_ll("hwaddr", ifa->ifa_addr);
	if (ifa->ifa_broadaddr) print_sockaddr_ll("hwbroad", ifa->ifa_addr);
	} else if (family == AF_INET \|\| family == AF_INET6) {
	if (ifa->ifa_addr) print_sockaddr_inet("address", ifa->ifa_addr);
	if (ifa->ifa_broadaddr && (ifa->ifa_flags & (IFF_BROADCAST \| IFF_POINTOPOINT)) != 0) {
	print_sockaddr_inet((ifa->ifa_flags & IFF_BROADCAST) ? "broadcast" : "destination",
	ifa->ifa_broadaddr);
	}
	}

	fflush(stdout);
	}

	freeifaddrs(addrs);
	}

	TEST(ifaddrs, inet6_scope_ids) {
	ifaddrs* addrs;
	ASSERT_EQ(0, getifaddrs(&addrs));

	for (ifaddrs* ifa = addrs; ifa != nullptr; ifa = ifa->ifa_next) {
	if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6) {
	sockaddr_in6* sa6 = reinterpret_cast<sockaddr_in6*>(ifa->ifa_addr);
	// Any link-local IPv6 address should have a scope id. (http://b/27219454.)
	// 0 isn't a valid interface index, so that would mean the scope id wasn't set.
	if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr) \|\| IN6_IS_ADDR_MC_LINKLOCAL(&sa6->sin6_addr)) {
	ASSERT_NE(sa6->sin6_scope_id, 0U);
	}
	}
	}

	freeifaddrs(addrs);
	}