src/net/base/address_tracker_linux.cc - cobalt - Git at Google

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "net/base/address_tracker_linux.h"

 #include <errno.h>
 #include <linux/if.h>

 #include "base/logging.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/threading/thread_restrictions.h"
 #include "net/base/network_change_notifier_linux.h"

 namespace net {
 namespace internal {

 namespace {

 // Retrieves address from NETLINK address message.
 bool GetAddress(const struct nlmsghdr* header, IPAddressNumber* out) {
   const struct ifaddrmsg* msg =
       reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
   size_t address_length = 0;
   switch (msg->ifa_family) {
     case AF_INET:
       address_length = kIPv4AddressSize;
       break;
     case AF_INET6:
       address_length = kIPv6AddressSize;
       break;
     default:
       // Unknown family.
       return false;
   }
   // Use IFA_ADDRESS unless IFA_LOCAL is present. This behavior here is based on
   // getaddrinfo in glibc (check_pf.c). Judging from kernel implementation of
   // NETLINK, IPv4 addresses have only the IFA_ADDRESS attribute, while IPv6
   // have the IFA_LOCAL attribute.
   unsigned char* address = NULL;
   unsigned char* local = NULL;
   size_t length = IFA_PAYLOAD(header);
   for (const struct rtattr* attr =
            reinterpret_cast<const struct rtattr*>(IFA_RTA(msg));
        RTA_OK(attr, length);
        attr = RTA_NEXT(attr, length)) {
     switch (attr->rta_type) {
       case IFA_ADDRESS:
         DCHECK_GE(RTA_PAYLOAD(attr), address_length);
         address = reinterpret_cast<unsigned char*>(RTA_DATA(attr));
         break;
       case IFA_LOCAL:
         DCHECK_GE(RTA_PAYLOAD(attr), address_length);
         local = reinterpret_cast<unsigned char*>(RTA_DATA(attr));
         break;
       default:
         break;
     }
   }
   if (local)
     address = local;
   if (!address)
     return false;
   out->assign(address, address + address_length);
   return true;
 }

 }  // namespace

 AddressTrackerLinux::AddressTrackerLinux(const base::Closure& address_callback,
                                          const base::Closure& link_callback)
     : address_callback_(address_callback),
       link_callback_(link_callback),
       netlink_fd_(-1),
       is_offline_(true),
       is_offline_initialized_(false),
       is_offline_initialized_cv_(&is_offline_lock_) {
   DCHECK(!address_callback.is_null());
   DCHECK(!link_callback.is_null());
 }

 AddressTrackerLinux::~AddressTrackerLinux() {
   CloseSocket();
 }

 void AddressTrackerLinux::Init() {
   netlink_fd_ = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
   if (netlink_fd_ < 0) {
     PLOG(ERROR) << "Could not create NETLINK socket";
     AbortAndForceOnline();
     return;
   }

   // Request notifications.
   struct sockaddr_nl addr = {};
   addr.nl_family = AF_NETLINK;
   addr.nl_pid = getpid();
   // TODO(szym): Track RTMGRP_LINK as well for ifi_type, http://crbug.com/113993
   addr.nl_groups = RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR | RTMGRP_NOTIFY |
       RTMGRP_LINK;
   int rv = bind(netlink_fd_,
                 reinterpret_cast<struct sockaddr*>(&addr),
                 sizeof(addr));
   if (rv < 0) {
     PLOG(ERROR) << "Could not bind NETLINK socket";
     AbortAndForceOnline();
     return;
   }

   // Request dump of addresses.
   struct sockaddr_nl peer = {};
   peer.nl_family = AF_NETLINK;

   struct {
     struct nlmsghdr header;
     struct rtgenmsg msg;
   } request = {};

   request.header.nlmsg_len = NLMSG_LENGTH(sizeof(request.msg));
   request.header.nlmsg_type = RTM_GETADDR;
   request.header.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
   request.header.nlmsg_pid = getpid();
   request.msg.rtgen_family = AF_UNSPEC;

   rv = HANDLE_EINTR(sendto(netlink_fd_, &request, request.header.nlmsg_len,
                            0, reinterpret_cast<struct sockaddr*>(&peer),
                            sizeof(peer)));
   if (rv < 0) {
     PLOG(ERROR) << "Could not send NETLINK request";
     AbortAndForceOnline();
     return;
   }

   // Consume pending message to populate the AddressMap, but don't notify.
   // Sending another request without first reading responses results in EBUSY.
   bool address_changed;
   bool link_changed;
   ReadMessages(&address_changed, &link_changed);

   // Request dump of link state
   request.header.nlmsg_type = RTM_GETLINK;

   rv = HANDLE_EINTR(sendto(netlink_fd_, &request, request.header.nlmsg_len, 0,
                            reinterpret_cast<struct sockaddr*>(&peer),
                            sizeof(peer)));
   if (rv < 0) {
     PLOG(ERROR) << "Could not send NETLINK request";
     AbortAndForceOnline();
     return;
   }

   // Consume pending message to populate links_online_, but don't notify.
   ReadMessages(&address_changed, &link_changed);
   {
     base::AutoLock lock(is_offline_lock_);
     is_offline_initialized_ = true;
     is_offline_initialized_cv_.Signal();
   }

   rv = MessageLoopForIO::current()->WatchFileDescriptor(
       netlink_fd_, true, MessageLoopForIO::WATCH_READ, &watcher_, this);
   if (rv < 0) {
     PLOG(ERROR) << "Could not watch NETLINK socket";
     AbortAndForceOnline();
     return;
   }
 }

 void AddressTrackerLinux::AbortAndForceOnline() {
   CloseSocket();
   base::AutoLock lock(is_offline_lock_);
   is_offline_ = false;
   is_offline_initialized_ = true;
   is_offline_initialized_cv_.Signal();
 }

 AddressTrackerLinux::AddressMap AddressTrackerLinux::GetAddressMap() const {
   base::AutoLock lock(address_map_lock_);
   return address_map_;
 }

 NetworkChangeNotifier::ConnectionType
 AddressTrackerLinux::GetCurrentConnectionType() {
   // http://crbug.com/125097
   base::ThreadRestrictions::ScopedAllowWait allow_wait;
   base::AutoLock lock(is_offline_lock_);
   // Make sure the initial offline state is set before returning.
   while (!is_offline_initialized_) {
     is_offline_initialized_cv_.Wait();
   }
   // TODO(droger): Return something more detailed than CONNECTION_UNKNOWN.
   // http://crbug.com/160537
   return is_offline_ ? NetworkChangeNotifier::CONNECTION_NONE :
                        NetworkChangeNotifier::CONNECTION_UNKNOWN;
 }

 void AddressTrackerLinux::ReadMessages(bool* address_changed,
                                        bool* link_changed) {
   *address_changed = false;
   *link_changed = false;
   char buffer[4096];
   bool first_loop = true;
   for (;;) {
     int rv = HANDLE_EINTR(recv(netlink_fd_,
                                buffer,
                                sizeof(buffer),
                                // Block the first time through loop.
                                first_loop ? 0 : MSG_DONTWAIT));
     first_loop = false;
     if (rv == 0) {
       LOG(ERROR) << "Unexpected shutdown of NETLINK socket.";
       return;
     }
     if (rv < 0) {
       if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
         break;
       PLOG(ERROR) << "Failed to recv from netlink socket";
       return;
     }
     HandleMessage(buffer, rv, address_changed, link_changed);
   };
   if (*link_changed) {
     base::AutoLock lock(is_offline_lock_);
     is_offline_ = online_links_.empty();
   }
 }

 void AddressTrackerLinux::HandleMessage(const char* buffer,
                                         size_t length,
                                         bool* address_changed,
                                         bool* link_changed) {
   DCHECK(buffer);
   for (const struct nlmsghdr* header =
           reinterpret_cast<const struct nlmsghdr*>(buffer);
        NLMSG_OK(header, length);
        header = NLMSG_NEXT(header, length)) {
     switch (header->nlmsg_type) {
       case NLMSG_DONE:
         return;
       case NLMSG_ERROR: {
         const struct nlmsgerr* msg =
             reinterpret_cast<struct nlmsgerr*>(NLMSG_DATA(header));
         LOG(ERROR) << "Unexpected netlink error " << msg->error << ".";
       } return;
       case RTM_NEWADDR: {
         IPAddressNumber address;
         if (GetAddress(header, &address)) {
           base::AutoLock lock(address_map_lock_);
           const struct ifaddrmsg* msg =
               reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
           // Only indicate change if the address is new or ifaddrmsg info has
           // changed.
           AddressMap::iterator it = address_map_.find(address);
           if (it == address_map_.end()) {
             address_map_.insert(it, std::make_pair(address, *msg));
             *address_changed = true;
           } else if (memcmp(&it->second, msg, sizeof(*msg))) {
             it->second = *msg;
             *address_changed = true;
           }
         }
       } break;
       case RTM_DELADDR: {
         IPAddressNumber address;
         if (GetAddress(header, &address)) {
           base::AutoLock lock(address_map_lock_);
           if (address_map_.erase(address))
             *address_changed = true;
         }
       } break;
       case RTM_NEWLINK: {
         const struct ifinfomsg* msg =
             reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
         if (!(msg->ifi_flags & IFF_LOOPBACK) && (msg->ifi_flags & IFF_UP) &&
             (msg->ifi_flags & IFF_LOWER_UP) && (msg->ifi_flags & IFF_RUNNING)) {
           if (online_links_.insert(msg->ifi_index).second)
             *link_changed = true;
         } else {
           if (online_links_.erase(msg->ifi_index))
             *link_changed = true;
         }
       } break;
       case RTM_DELLINK: {
         const struct ifinfomsg* msg =
             reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
         if (online_links_.erase(msg->ifi_index))
           *link_changed = true;
       } break;
       default:
         break;
     }
   }
 }

 void AddressTrackerLinux::OnFileCanReadWithoutBlocking(int fd) {
   DCHECK_EQ(netlink_fd_, fd);
   bool address_changed;
   bool link_changed;
   ReadMessages(&address_changed, &link_changed);
   if (address_changed)
     address_callback_.Run();
   if (link_changed)
     link_callback_.Run();
 }

 void AddressTrackerLinux::OnFileCanWriteWithoutBlocking(int /* fd */) {}

 void AddressTrackerLinux::CloseSocket() {
   if (netlink_fd_ >= 0 && HANDLE_EINTR(close(netlink_fd_)) < 0)
     PLOG(ERROR) << "Could not close NETLINK socket.";
   netlink_fd_ = -1;
 }

 }  // namespace internal
 }  // namespace net
	// Copyright (c) 2012 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "net/base/address_tracker_linux.h"

	#include <errno.h>
	#include <linux/if.h>

	#include "base/logging.h"
	#include "base/posix/eintr_wrapper.h"
	#include "base/threading/thread_restrictions.h"
	#include "net/base/network_change_notifier_linux.h"

	namespace net {
	namespace internal {

	namespace {

	// Retrieves address from NETLINK address message.
	bool GetAddress(const struct nlmsghdr* header, IPAddressNumber* out) {
	const struct ifaddrmsg* msg =
	reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
	size_t address_length = 0;
	switch (msg->ifa_family) {
	case AF_INET:
	address_length = kIPv4AddressSize;
	break;
	case AF_INET6:
	address_length = kIPv6AddressSize;
	break;
	default:
	// Unknown family.
	return false;
	}
	// Use IFA_ADDRESS unless IFA_LOCAL is present. This behavior here is based on
	// getaddrinfo in glibc (check_pf.c). Judging from kernel implementation of
	// NETLINK, IPv4 addresses have only the IFA_ADDRESS attribute, while IPv6
	// have the IFA_LOCAL attribute.
	unsigned char* address = NULL;
	unsigned char* local = NULL;
	size_t length = IFA_PAYLOAD(header);
	for (const struct rtattr* attr =
	reinterpret_cast<const struct rtattr*>(IFA_RTA(msg));
	RTA_OK(attr, length);
	attr = RTA_NEXT(attr, length)) {
	switch (attr->rta_type) {
	case IFA_ADDRESS:
	DCHECK_GE(RTA_PAYLOAD(attr), address_length);
	address = reinterpret_cast<unsigned char*>(RTA_DATA(attr));
	break;
	case IFA_LOCAL:
	DCHECK_GE(RTA_PAYLOAD(attr), address_length);
	local = reinterpret_cast<unsigned char*>(RTA_DATA(attr));
	break;
	default:
	break;
	}
	}
	if (local)
	address = local;
	if (!address)
	return false;
	out->assign(address, address + address_length);
	return true;
	}

	} // namespace

	AddressTrackerLinux::AddressTrackerLinux(const base::Closure& address_callback,
	const base::Closure& link_callback)
	: address_callback_(address_callback),
	link_callback_(link_callback),
	netlink_fd_(-1),
	is_offline_(true),
	is_offline_initialized_(false),
	is_offline_initialized_cv_(&is_offline_lock_) {
	DCHECK(!address_callback.is_null());
	DCHECK(!link_callback.is_null());
	}

	AddressTrackerLinux::~AddressTrackerLinux() {
	CloseSocket();
	}

	void AddressTrackerLinux::Init() {
	netlink_fd_ = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
	if (netlink_fd_ < 0) {
	PLOG(ERROR) << "Could not create NETLINK socket";
	AbortAndForceOnline();
	return;
	}

	// Request notifications.
	struct sockaddr_nl addr = {};
	addr.nl_family = AF_NETLINK;
	addr.nl_pid = getpid();
	// TODO(szym): Track RTMGRP_LINK as well for ifi_type, http://crbug.com/113993
	addr.nl_groups = RTMGRP_IPV4_IFADDR \| RTMGRP_IPV6_IFADDR \| RTMGRP_NOTIFY \|
	RTMGRP_LINK;
	int rv = bind(netlink_fd_,
	reinterpret_cast<struct sockaddr*>(&addr),
	sizeof(addr));
	if (rv < 0) {
	PLOG(ERROR) << "Could not bind NETLINK socket";
	AbortAndForceOnline();
	return;
	}

	// Request dump of addresses.
	struct sockaddr_nl peer = {};
	peer.nl_family = AF_NETLINK;

	struct {
	struct nlmsghdr header;
	struct rtgenmsg msg;
	} request = {};

	request.header.nlmsg_len = NLMSG_LENGTH(sizeof(request.msg));
	request.header.nlmsg_type = RTM_GETADDR;
	request.header.nlmsg_flags = NLM_F_REQUEST \| NLM_F_DUMP;
	request.header.nlmsg_pid = getpid();
	request.msg.rtgen_family = AF_UNSPEC;

	rv = HANDLE_EINTR(sendto(netlink_fd_, &request, request.header.nlmsg_len,
	0, reinterpret_cast<struct sockaddr*>(&peer),
	sizeof(peer)));
	if (rv < 0) {
	PLOG(ERROR) << "Could not send NETLINK request";
	AbortAndForceOnline();
	return;
	}

	// Consume pending message to populate the AddressMap, but don't notify.
	// Sending another request without first reading responses results in EBUSY.
	bool address_changed;
	bool link_changed;
	ReadMessages(&address_changed, &link_changed);

	// Request dump of link state
	request.header.nlmsg_type = RTM_GETLINK;

	rv = HANDLE_EINTR(sendto(netlink_fd_, &request, request.header.nlmsg_len, 0,
	reinterpret_cast<struct sockaddr*>(&peer),
	sizeof(peer)));
	if (rv < 0) {
	PLOG(ERROR) << "Could not send NETLINK request";
	AbortAndForceOnline();
	return;
	}

	// Consume pending message to populate links_online_, but don't notify.
	ReadMessages(&address_changed, &link_changed);
	{
	base::AutoLock lock(is_offline_lock_);
	is_offline_initialized_ = true;
	is_offline_initialized_cv_.Signal();
	}

	rv = MessageLoopForIO::current()->WatchFileDescriptor(
	netlink_fd_, true, MessageLoopForIO::WATCH_READ, &watcher_, this);
	if (rv < 0) {
	PLOG(ERROR) << "Could not watch NETLINK socket";
	AbortAndForceOnline();
	return;
	}
	}

	void AddressTrackerLinux::AbortAndForceOnline() {
	CloseSocket();
	base::AutoLock lock(is_offline_lock_);
	is_offline_ = false;
	is_offline_initialized_ = true;
	is_offline_initialized_cv_.Signal();
	}

	AddressTrackerLinux::AddressMap AddressTrackerLinux::GetAddressMap() const {
	base::AutoLock lock(address_map_lock_);
	return address_map_;
	}

	NetworkChangeNotifier::ConnectionType
	AddressTrackerLinux::GetCurrentConnectionType() {
	// http://crbug.com/125097
	base::ThreadRestrictions::ScopedAllowWait allow_wait;
	base::AutoLock lock(is_offline_lock_);
	// Make sure the initial offline state is set before returning.
	while (!is_offline_initialized_) {
	is_offline_initialized_cv_.Wait();
	}
	// TODO(droger): Return something more detailed than CONNECTION_UNKNOWN.
	// http://crbug.com/160537
	return is_offline_ ? NetworkChangeNotifier::CONNECTION_NONE :
	NetworkChangeNotifier::CONNECTION_UNKNOWN;
	}

	void AddressTrackerLinux::ReadMessages(bool* address_changed,
	bool* link_changed) {
	*address_changed = false;
	*link_changed = false;
	char buffer[4096];
	bool first_loop = true;
	for (;;) {
	int rv = HANDLE_EINTR(recv(netlink_fd_,
	buffer,
	sizeof(buffer),
	// Block the first time through loop.
	first_loop ? 0 : MSG_DONTWAIT));
	first_loop = false;
	if (rv == 0) {
	LOG(ERROR) << "Unexpected shutdown of NETLINK socket.";
	return;
	}
	if (rv < 0) {
	if ((errno == EAGAIN) \|\| (errno == EWOULDBLOCK))
	break;
	PLOG(ERROR) << "Failed to recv from netlink socket";
	return;
	}
	HandleMessage(buffer, rv, address_changed, link_changed);
	};
	if (*link_changed) {
	base::AutoLock lock(is_offline_lock_);
	is_offline_ = online_links_.empty();
	}
	}

	void AddressTrackerLinux::HandleMessage(const char* buffer,
	size_t length,
	bool* address_changed,
	bool* link_changed) {
	DCHECK(buffer);
	for (const struct nlmsghdr* header =
	reinterpret_cast<const struct nlmsghdr*>(buffer);
	NLMSG_OK(header, length);
	header = NLMSG_NEXT(header, length)) {
	switch (header->nlmsg_type) {
	case NLMSG_DONE:
	return;
	case NLMSG_ERROR: {
	const struct nlmsgerr* msg =
	reinterpret_cast<struct nlmsgerr*>(NLMSG_DATA(header));
	LOG(ERROR) << "Unexpected netlink error " << msg->error << ".";
	} return;
	case RTM_NEWADDR: {
	IPAddressNumber address;
	if (GetAddress(header, &address)) {
	base::AutoLock lock(address_map_lock_);
	const struct ifaddrmsg* msg =
	reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
	// Only indicate change if the address is new or ifaddrmsg info has
	// changed.
	AddressMap::iterator it = address_map_.find(address);
	if (it == address_map_.end()) {
	address_map_.insert(it, std::make_pair(address, *msg));
	*address_changed = true;
	} else if (memcmp(&it->second, msg, sizeof(*msg))) {
	it->second = *msg;
	*address_changed = true;
	}
	}
	} break;
	case RTM_DELADDR: {
	IPAddressNumber address;
	if (GetAddress(header, &address)) {
	base::AutoLock lock(address_map_lock_);
	if (address_map_.erase(address))
	*address_changed = true;
	}
	} break;
	case RTM_NEWLINK: {
	const struct ifinfomsg* msg =
	reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
	if (!(msg->ifi_flags & IFF_LOOPBACK) && (msg->ifi_flags & IFF_UP) &&
	(msg->ifi_flags & IFF_LOWER_UP) && (msg->ifi_flags & IFF_RUNNING)) {
	if (online_links_.insert(msg->ifi_index).second)
	*link_changed = true;
	} else {
	if (online_links_.erase(msg->ifi_index))
	*link_changed = true;
	}
	} break;
	case RTM_DELLINK: {
	const struct ifinfomsg* msg =
	reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
	if (online_links_.erase(msg->ifi_index))
	*link_changed = true;
	} break;
	default:
	break;
	}
	}
	}

	void AddressTrackerLinux::OnFileCanReadWithoutBlocking(int fd) {
	DCHECK_EQ(netlink_fd_, fd);
	bool address_changed;
	bool link_changed;
	ReadMessages(&address_changed, &link_changed);
	if (address_changed)
	address_callback_.Run();
	if (link_changed)
	link_callback_.Run();
	}

	void AddressTrackerLinux::OnFileCanWriteWithoutBlocking(int /* fd */) {}

	void AddressTrackerLinux::CloseSocket() {
	if (netlink_fd_ >= 0 && HANDLE_EINTR(close(netlink_fd_)) < 0)
	PLOG(ERROR) << "Could not close NETLINK socket.";
	netlink_fd_ = -1;
	}

	} // namespace internal
	} // namespace net