src/starboard/shared/linux/socket_get_interface_address.cc - cobalt - Git at Google

 // Copyright 2017 The Cobalt Authors. All Rights Reserved.
 //
 // 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 "starboard/socket.h"

 // linux/if.h assumes the symbols for structs defined in ifaddrs.h are
 // already present. These includes must be above <linux/if.h> below.
 #include <arpa/inet.h>
 #include <ifaddrs.h>

 #if SB_HAS_QUIRK(SOCKET_BSD_HEADERS)
 #include <errno.h>
 #include <net/if.h>
 #include <net/if_dl.h>
 #else
 #include <linux/if.h>
 #include <linux/if_addr.h>
 #include <netdb.h>
 #endif

 #include <netinet/in.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>

 #include "starboard/byte_swap.h"
 #include "starboard/log.h"
 #include "starboard/memory.h"
 #include "starboard/shared/posix/socket_internal.h"

 namespace sbposix = starboard::shared::posix;

 namespace {

 // TODO: Move this constant to socket.h.
 const int kIPv6AddressSize = 16;

 bool IsAnyAddress(const SbSocketAddress& address) {
   switch (address.type) {
     case kSbSocketAddressTypeIpv4:
       return (address.address[0] == 0 && address.address[1] == 0 &&
               address.address[2] == 0 && address.address[3] == 0);
 #if SB_HAS(IPV6)
     case kSbSocketAddressTypeIpv6: {
       bool found_nonzero = false;
       for (std::size_t i = 0; i != kIPv6AddressSize; ++i) {
         found_nonzero |= (address.address[i] != 0);
       }
       return !found_nonzero;
     }
 #endif
     default:
       SB_NOTREACHED() << "Invalid address type " << address.type;
       break;
   }

   return false;
 }

 template <typename T, int source_size>
 void CopyIntoObjectFromArray(T* out_destination,
                              const unsigned char(&source)[source_size]) {
   SB_COMPILE_ASSERT(sizeof(T) <= source_size, destination_is_too_small);
   SbMemoryCopy(out_destination, source, sizeof(T));
 }

 bool GetPotentialMatch(const sockaddr* input_addr,
                        const in_addr** out_interface_addr) {
   if (!input_addr || input_addr->sa_family != AF_INET) {
     *out_interface_addr = NULL;
     return false;
   }

   const sockaddr_in* v4input_addr =
       reinterpret_cast<const sockaddr_in*>(input_addr);
   *out_interface_addr = &(v4input_addr->sin_addr);
   return true;
 }

 bool GetPotentialMatch(const sockaddr* input_addr,
                        const in6_addr** out_interface_addr) {
   if (!input_addr || input_addr->sa_family != AF_INET6) {
     *out_interface_addr = NULL;
     return false;
   }

   const sockaddr_in6* v6input_addr =
       reinterpret_cast<const sockaddr_in6*>(input_addr);
   *out_interface_addr = &(v6input_addr->sin6_addr);
   return true;
 }

 template <typename in_addr_type>
 bool GetNetmaskForInterfaceAddress(const SbSocketAddress& interface_address,
                                    SbSocketAddress* out_netmask) {
   SB_DCHECK((interface_address.type == kSbSocketAddressTypeIpv4) ||
             (interface_address.type == kSbSocketAddressTypeIpv6));
   struct ifaddrs* interface_addrs = NULL;

   int retval = getifaddrs(&interface_addrs);
   if (retval != 0) {
     return false;
   }

   in_addr_type to_match;
   CopyIntoObjectFromArray(&to_match, interface_address.address);

   bool found_netmask = false;
   for (struct ifaddrs* interface = interface_addrs; interface != NULL;
        interface = interface->ifa_next) {
     if (!(IFF_UP & interface->ifa_flags) ||
         (IFF_LOOPBACK & interface->ifa_flags)) {
       continue;
     }

     const in_addr_type* potential_match;
     if (!GetPotentialMatch(interface->ifa_addr, &potential_match))
       continue;

     if (SbMemoryCompare(&to_match, potential_match, sizeof(in_addr_type)) !=
         0) {
       continue;
     }

     sbposix::SockAddr sock_addr;
     sock_addr.FromSockaddr(interface->ifa_netmask);
     if (sock_addr.ToSbSocketAddress(out_netmask)) {
       found_netmask = true;
       break;
     }
   }

   freeifaddrs(interface_addrs);

   return found_netmask;
 }

 bool GetNetMaskForInterfaceAddress(const SbSocketAddress& interface_address,
                                    SbSocketAddress* out_netmask) {
   SB_DCHECK(out_netmask);

   switch (interface_address.type) {
     case kSbSocketAddressTypeIpv4:
       return GetNetmaskForInterfaceAddress<in_addr>(interface_address,
                                                     out_netmask);
 #if SB_HAS(IPV6)
     case kSbSocketAddressTypeIpv6:
       return GetNetmaskForInterfaceAddress<in6_addr>(interface_address,
                                                      out_netmask);
 #endif
     default:
       SB_NOTREACHED() << "Invalid address type " << interface_address.type;
       break;
   }

   return false;
 }

 bool FindIPv4InterfaceIP(SbSocketAddress* out_interface_ip,
                          SbSocketAddress* out_netmask) {
   if (out_interface_ip == NULL) {
     SB_NOTREACHED() << "out_interface_ip must be specified";
     return false;
   }
   struct ifaddrs* interface_addrs = NULL;

   int retval = getifaddrs(&interface_addrs);
   if (retval != 0) {
     return false;
   }

   bool success = false;
   for (struct ifaddrs* interface = interface_addrs; interface != NULL;
        interface = interface->ifa_next) {
     if (!(IFF_UP & interface->ifa_flags) ||
         (IFF_LOOPBACK & interface->ifa_flags)) {
       continue;
     }

     const struct sockaddr* addr = interface->ifa_addr;
     const struct sockaddr* netmask = interface->ifa_netmask;
     if (!addr || !netmask || (addr->sa_family != AF_INET)) {
       // IPv4 addresses only.
       continue;
     }

     sbposix::SockAddr sock_addr;
     sock_addr.FromSockaddr(addr);
     if (sock_addr.ToSbSocketAddress(out_interface_ip)) {
       if (out_netmask) {
         sbposix::SockAddr netmask_addr;
         netmask_addr.FromSockaddr(netmask);
         if (!netmask_addr.ToSbSocketAddress(out_netmask)) {
           continue;
         }
       }

       success = true;
       break;
     }
   }

   freeifaddrs(interface_addrs);

   return success;
 }

 #if SB_HAS(IPV6)
 bool IsUniqueLocalAddress(const unsigned char ip[16]) {
   // Unique Local Addresses are in fd08::/8.
   return ip[0] == 0xfd && ip[1] == 0x08;
 }

 bool FindIPv6InterfaceIP(SbSocketAddress* out_interface_ip,
                          SbSocketAddress* out_netmask) {
   if (!out_interface_ip) {
     SB_NOTREACHED() << "out_interface_ip must be specified";
     return false;
   }
   struct ifaddrs* interface_addrs = NULL;

   int retval = getifaddrs(&interface_addrs);
   if (retval != 0) {
     return false;
   }

   int max_scope_interface_value = -1;

   bool ip_found = false;
   SbSocketAddress temp_interface_ip;
   SbSocketAddress temp_netmask;

   for (struct ifaddrs* interface = interface_addrs; interface != NULL;
        interface = interface->ifa_next) {
     if (!(IFF_UP & interface->ifa_flags) ||
         (IFF_LOOPBACK & interface->ifa_flags)) {
       continue;
     }

     const struct sockaddr* addr = interface->ifa_addr;
     const struct sockaddr* netmask = interface->ifa_netmask;
     if (!addr || !netmask || addr->sa_family != AF_INET6) {
       // IPv6 addresses only.
       continue;
     }

     const in6_addr* potential_match;
     if (!GetPotentialMatch(interface->ifa_addr, &potential_match))
       continue;

     // Check the IP for loopback again, just in case flags were incorrect.
     if (IN6_IS_ADDR_LOOPBACK(potential_match) ||
         IN6_IS_ADDR_LINKLOCAL(potential_match)) {
       continue;
     }

     const sockaddr_in6* v6addr =
         reinterpret_cast<const sockaddr_in6*>(interface->ifa_addr);
     if (!v6addr) {
       continue;
     }

     int current_interface_scope = v6addr->sin6_scope_id;

     if (IsUniqueLocalAddress(v6addr->sin6_addr.s6_addr)) {
       // ULAs have global scope, but not globally routable.  So prefer
       // non ULA addresses with global scope by adjusting their "scope"
       current_interface_scope -= 1;
     }

     if (current_interface_scope <= max_scope_interface_value) {
       continue;
     }
     max_scope_interface_value = current_interface_scope;

     sbposix::SockAddr sock_addr;
     sock_addr.FromSockaddr(addr);
     if (sock_addr.ToSbSocketAddress(&temp_interface_ip)) {
       if (netmask) {
         sbposix::SockAddr netmask_addr;
         netmask_addr.FromSockaddr(netmask);
         if (!netmask_addr.ToSbSocketAddress(&temp_netmask)) {
           continue;
         }
       }

       ip_found = true;
     }
   }

   freeifaddrs(interface_addrs);

   if (!ip_found) {
     return false;
   }

   SbMemoryCopy(out_interface_ip, &temp_interface_ip, sizeof(SbSocketAddress));
   if (out_netmask != NULL) {
     SbMemoryCopy(out_netmask, &temp_netmask, sizeof(SbSocketAddress));
   }

   return true;
 }
 #endif

 bool FindInterfaceIP(const SbSocketAddressType type,
                      SbSocketAddress* out_interface_ip,
                      SbSocketAddress* out_netmask) {
   switch (type) {
     case kSbSocketAddressTypeIpv4:
       return FindIPv4InterfaceIP(out_interface_ip, out_netmask);
 #if SB_HAS(IPV6)
     case kSbSocketAddressTypeIpv6:
       return FindIPv6InterfaceIP(out_interface_ip, out_netmask);
 #endif
     default:
       SB_NOTREACHED() << "Invalid socket address type " << type;
   }

   return false;
 }

 bool FindSourceAddressForDestination(const SbSocketAddress& destination,
                                      SbSocketAddress* out_source_address) {
   SbSocket socket = SbSocketCreate(destination.type, kSbSocketProtocolUdp);
   if (!SbSocketIsValid(socket)) {
     return false;
   }

   SbSocketError connect_retval = SbSocketConnect(socket, &destination);
   if (connect_retval != kSbSocketOk) {
     bool socket_destroyed = SbSocketDestroy(socket);
     SB_DCHECK(socket_destroyed);
     return false;
   }

   bool success = SbSocketGetLocalAddress(socket, out_source_address);
   bool socket_destroyed = SbSocketDestroy(socket);
   SB_DCHECK(socket_destroyed);
   return success;
 }

 }  // namespace

 bool SbSocketGetInterfaceAddress(const SbSocketAddress* const destination,
                                  SbSocketAddress* out_source_address,
                                  SbSocketAddress* out_netmask) {
   if (!out_source_address) {
     return false;
   }

   if (destination == NULL) {
 #if SB_HAS(IPV6)
     // Return either a v4 or a v6 address.  Per spec.
     return (FindIPv4InterfaceIP(out_source_address, out_netmask) ||
             FindIPv6InterfaceIP(out_source_address, out_netmask));
 #else
     return FindIPv4InterfaceIP(out_source_address, out_netmask);
 #endif

   } else if (IsAnyAddress(*destination)) {
     return FindInterfaceIP(destination->type, out_source_address, out_netmask);
   } else {
     SbSocketAddress destination_copy = *destination;
     // On some platforms, passing a socket address with port 0 to connect()
     // results in EADDRNOTAVAIL.
     if (!destination_copy.port) {
       destination_copy.port = 80;
     }
     return (
         FindSourceAddressForDestination(destination_copy, out_source_address) &&
         GetNetMaskForInterfaceAddress(*out_source_address, out_netmask));
   }

   return false;
 }
	// Copyright 2017 The Cobalt Authors. All Rights Reserved.
	//
	// 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 "starboard/socket.h"

	// linux/if.h assumes the symbols for structs defined in ifaddrs.h are
	// already present. These includes must be above <linux/if.h> below.
	#include <arpa/inet.h>
	#include <ifaddrs.h>

	#if SB_HAS_QUIRK(SOCKET_BSD_HEADERS)
	#include <errno.h>
	#include <net/if.h>
	#include <net/if_dl.h>
	#else
	#include <linux/if.h>
	#include <linux/if_addr.h>
	#include <netdb.h>
	#endif

	#include <netinet/in.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <sys/types.h>

	#include "starboard/byte_swap.h"
	#include "starboard/log.h"
	#include "starboard/memory.h"
	#include "starboard/shared/posix/socket_internal.h"

	namespace sbposix = starboard::shared::posix;

	namespace {

	// TODO: Move this constant to socket.h.
	const int kIPv6AddressSize = 16;

	bool IsAnyAddress(const SbSocketAddress& address) {
	switch (address.type) {
	case kSbSocketAddressTypeIpv4:
	return (address.address[0] == 0 && address.address[1] == 0 &&
	address.address[2] == 0 && address.address[3] == 0);
	#if SB_HAS(IPV6)
	case kSbSocketAddressTypeIpv6: {
	bool found_nonzero = false;
	for (std::size_t i = 0; i != kIPv6AddressSize; ++i) {
	found_nonzero \|= (address.address[i] != 0);
	}
	return !found_nonzero;
	}
	#endif
	default:
	SB_NOTREACHED() << "Invalid address type " << address.type;
	break;
	}

	return false;
	}

	template <typename T, int source_size>
	void CopyIntoObjectFromArray(T* out_destination,
	const unsigned char(&source)[source_size]) {
	SB_COMPILE_ASSERT(sizeof(T) <= source_size, destination_is_too_small);
	SbMemoryCopy(out_destination, source, sizeof(T));
	}

	bool GetPotentialMatch(const sockaddr* input_addr,
	const in_addr** out_interface_addr) {
	if (!input_addr \|\| input_addr->sa_family != AF_INET) {
	*out_interface_addr = NULL;
	return false;
	}

	const sockaddr_in* v4input_addr =
	reinterpret_cast<const sockaddr_in*>(input_addr);
	*out_interface_addr = &(v4input_addr->sin_addr);
	return true;
	}

	bool GetPotentialMatch(const sockaddr* input_addr,
	const in6_addr** out_interface_addr) {
	if (!input_addr \|\| input_addr->sa_family != AF_INET6) {
	*out_interface_addr = NULL;
	return false;
	}

	const sockaddr_in6* v6input_addr =
	reinterpret_cast<const sockaddr_in6*>(input_addr);
	*out_interface_addr = &(v6input_addr->sin6_addr);
	return true;
	}

	template <typename in_addr_type>
	bool GetNetmaskForInterfaceAddress(const SbSocketAddress& interface_address,
	SbSocketAddress* out_netmask) {
	SB_DCHECK((interface_address.type == kSbSocketAddressTypeIpv4) \|\|
	(interface_address.type == kSbSocketAddressTypeIpv6));
	struct ifaddrs* interface_addrs = NULL;

	int retval = getifaddrs(&interface_addrs);
	if (retval != 0) {
	return false;
	}

	in_addr_type to_match;
	CopyIntoObjectFromArray(&to_match, interface_address.address);

	bool found_netmask = false;
	for (struct ifaddrs* interface = interface_addrs; interface != NULL;
	interface = interface->ifa_next) {
	if (!(IFF_UP & interface->ifa_flags) \|\|
	(IFF_LOOPBACK & interface->ifa_flags)) {
	continue;
	}

	const in_addr_type* potential_match;
	if (!GetPotentialMatch(interface->ifa_addr, &potential_match))
	continue;

	if (SbMemoryCompare(&to_match, potential_match, sizeof(in_addr_type)) !=
	0) {
	continue;
	}

	sbposix::SockAddr sock_addr;
	sock_addr.FromSockaddr(interface->ifa_netmask);
	if (sock_addr.ToSbSocketAddress(out_netmask)) {
	found_netmask = true;
	break;
	}
	}

	freeifaddrs(interface_addrs);

	return found_netmask;
	}

	bool GetNetMaskForInterfaceAddress(const SbSocketAddress& interface_address,
	SbSocketAddress* out_netmask) {
	SB_DCHECK(out_netmask);

	switch (interface_address.type) {
	case kSbSocketAddressTypeIpv4:
	return GetNetmaskForInterfaceAddress<in_addr>(interface_address,
	out_netmask);
	#if SB_HAS(IPV6)
	case kSbSocketAddressTypeIpv6:
	return GetNetmaskForInterfaceAddress<in6_addr>(interface_address,
	out_netmask);
	#endif
	default:
	SB_NOTREACHED() << "Invalid address type " << interface_address.type;
	break;
	}

	return false;
	}

	bool FindIPv4InterfaceIP(SbSocketAddress* out_interface_ip,
	SbSocketAddress* out_netmask) {
	if (out_interface_ip == NULL) {
	SB_NOTREACHED() << "out_interface_ip must be specified";
	return false;
	}
	struct ifaddrs* interface_addrs = NULL;

	int retval = getifaddrs(&interface_addrs);
	if (retval != 0) {
	return false;
	}

	bool success = false;
	for (struct ifaddrs* interface = interface_addrs; interface != NULL;
	interface = interface->ifa_next) {
	if (!(IFF_UP & interface->ifa_flags) \|\|
	(IFF_LOOPBACK & interface->ifa_flags)) {
	continue;
	}

	const struct sockaddr* addr = interface->ifa_addr;
	const struct sockaddr* netmask = interface->ifa_netmask;
	if (!addr \|\| !netmask \|\| (addr->sa_family != AF_INET)) {
	// IPv4 addresses only.
	continue;
	}

	sbposix::SockAddr sock_addr;
	sock_addr.FromSockaddr(addr);
	if (sock_addr.ToSbSocketAddress(out_interface_ip)) {
	if (out_netmask) {
	sbposix::SockAddr netmask_addr;
	netmask_addr.FromSockaddr(netmask);
	if (!netmask_addr.ToSbSocketAddress(out_netmask)) {
	continue;
	}
	}

	success = true;
	break;
	}
	}

	freeifaddrs(interface_addrs);

	return success;
	}

	#if SB_HAS(IPV6)
	bool IsUniqueLocalAddress(const unsigned char ip[16]) {
	// Unique Local Addresses are in fd08::/8.
	return ip[0] == 0xfd && ip[1] == 0x08;
	}

	bool FindIPv6InterfaceIP(SbSocketAddress* out_interface_ip,
	SbSocketAddress* out_netmask) {
	if (!out_interface_ip) {
	SB_NOTREACHED() << "out_interface_ip must be specified";
	return false;
	}
	struct ifaddrs* interface_addrs = NULL;

	int retval = getifaddrs(&interface_addrs);
	if (retval != 0) {
	return false;
	}

	int max_scope_interface_value = -1;

	bool ip_found = false;
	SbSocketAddress temp_interface_ip;
	SbSocketAddress temp_netmask;

	for (struct ifaddrs* interface = interface_addrs; interface != NULL;
	interface = interface->ifa_next) {
	if (!(IFF_UP & interface->ifa_flags) \|\|
	(IFF_LOOPBACK & interface->ifa_flags)) {
	continue;
	}

	const struct sockaddr* addr = interface->ifa_addr;
	const struct sockaddr* netmask = interface->ifa_netmask;
	if (!addr \|\| !netmask \|\| addr->sa_family != AF_INET6) {
	// IPv6 addresses only.
	continue;
	}

	const in6_addr* potential_match;
	if (!GetPotentialMatch(interface->ifa_addr, &potential_match))
	continue;

	// Check the IP for loopback again, just in case flags were incorrect.
	if (IN6_IS_ADDR_LOOPBACK(potential_match) \|\|
	IN6_IS_ADDR_LINKLOCAL(potential_match)) {
	continue;
	}

	const sockaddr_in6* v6addr =
	reinterpret_cast<const sockaddr_in6*>(interface->ifa_addr);
	if (!v6addr) {
	continue;
	}

	int current_interface_scope = v6addr->sin6_scope_id;

	if (IsUniqueLocalAddress(v6addr->sin6_addr.s6_addr)) {
	// ULAs have global scope, but not globally routable. So prefer
	// non ULA addresses with global scope by adjusting their "scope"
	current_interface_scope -= 1;
	}

	if (current_interface_scope <= max_scope_interface_value) {
	continue;
	}
	max_scope_interface_value = current_interface_scope;

	sbposix::SockAddr sock_addr;
	sock_addr.FromSockaddr(addr);
	if (sock_addr.ToSbSocketAddress(&temp_interface_ip)) {
	if (netmask) {
	sbposix::SockAddr netmask_addr;
	netmask_addr.FromSockaddr(netmask);
	if (!netmask_addr.ToSbSocketAddress(&temp_netmask)) {
	continue;
	}
	}

	ip_found = true;
	}
	}

	freeifaddrs(interface_addrs);

	if (!ip_found) {
	return false;
	}

	SbMemoryCopy(out_interface_ip, &temp_interface_ip, sizeof(SbSocketAddress));
	if (out_netmask != NULL) {
	SbMemoryCopy(out_netmask, &temp_netmask, sizeof(SbSocketAddress));
	}

	return true;
	}
	#endif

	bool FindInterfaceIP(const SbSocketAddressType type,
	SbSocketAddress* out_interface_ip,
	SbSocketAddress* out_netmask) {
	switch (type) {
	case kSbSocketAddressTypeIpv4:
	return FindIPv4InterfaceIP(out_interface_ip, out_netmask);
	#if SB_HAS(IPV6)
	case kSbSocketAddressTypeIpv6:
	return FindIPv6InterfaceIP(out_interface_ip, out_netmask);
	#endif
	default:
	SB_NOTREACHED() << "Invalid socket address type " << type;
	}

	return false;
	}

	bool FindSourceAddressForDestination(const SbSocketAddress& destination,
	SbSocketAddress* out_source_address) {
	SbSocket socket = SbSocketCreate(destination.type, kSbSocketProtocolUdp);
	if (!SbSocketIsValid(socket)) {
	return false;
	}

	SbSocketError connect_retval = SbSocketConnect(socket, &destination);
	if (connect_retval != kSbSocketOk) {
	bool socket_destroyed = SbSocketDestroy(socket);
	SB_DCHECK(socket_destroyed);
	return false;
	}

	bool success = SbSocketGetLocalAddress(socket, out_source_address);
	bool socket_destroyed = SbSocketDestroy(socket);
	SB_DCHECK(socket_destroyed);
	return success;
	}

	} // namespace

	bool SbSocketGetInterfaceAddress(const SbSocketAddress* const destination,
	SbSocketAddress* out_source_address,
	SbSocketAddress* out_netmask) {
	if (!out_source_address) {
	return false;
	}

	if (destination == NULL) {
	#if SB_HAS(IPV6)
	// Return either a v4 or a v6 address. Per spec.
	return (FindIPv4InterfaceIP(out_source_address, out_netmask) \|\|
	FindIPv6InterfaceIP(out_source_address, out_netmask));
	#else
	return FindIPv4InterfaceIP(out_source_address, out_netmask);
	#endif

	} else if (IsAnyAddress(*destination)) {
	return FindInterfaceIP(destination->type, out_source_address, out_netmask);
	} else {
	SbSocketAddress destination_copy = *destination;
	// On some platforms, passing a socket address with port 0 to connect()
	// results in EADDRNOTAVAIL.
	if (!destination_copy.port) {
	destination_copy.port = 80;
	}
	return (
	FindSourceAddressForDestination(destination_copy, out_source_address) &&
	GetNetMaskForInterfaceAddress(*out_source_address, out_netmask));
	}

	return false;
	}