blob: c38614973e1bc8b8e4db2e47a35c711d07464e6f [file] [log] [blame]
// 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 <stdint.h>
#include <sys/ioctl.h>
#include "base/bind_helpers.h"
#include "base/files/scoped_file.h"
#include "base/logging.h"
#include "base/message_loop/message_loop_current.h"
#include "base/optional.h"
#include "base/posix/eintr_wrapper.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/threading/thread_restrictions.h"
#include "net/base/network_interfaces_linux.h"
namespace net {
namespace internal {
namespace {
// Some kernel functions such as wireless_send_event and rtnetlink_ifinfo_prep
// may send spurious messages over rtnetlink. RTM_NEWLINK messages where
// ifi_change == 0 and rta_type == IFLA_WIRELESS should be ignored.
bool IgnoreWirelessChange(const struct nlmsghdr* header,
const struct ifinfomsg* msg) {
size_t length = IFLA_PAYLOAD(header);
for (const struct rtattr* attr = IFLA_RTA(msg); RTA_OK(attr, length);
attr = RTA_NEXT(attr, length)) {
if (attr->rta_type == IFLA_WIRELESS && msg->ifi_change == 0)
return true;
}
return false;
}
// Retrieves address from NETLINK address message.
// Sets |really_deprecated| for IPv6 addresses with preferred lifetimes of 0.
bool GetAddress(const struct nlmsghdr* header,
IPAddress* out,
bool* really_deprecated) {
if (really_deprecated)
*really_deprecated = false;
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 = IPAddress::kIPv4AddressSize;
break;
case AF_INET6:
address_length = IPAddress::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.
uint8_t* address = NULL;
uint8_t* 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<uint8_t*>(RTA_DATA(attr));
break;
case IFA_LOCAL:
DCHECK_GE(RTA_PAYLOAD(attr), address_length);
local = reinterpret_cast<uint8_t*>(RTA_DATA(attr));
break;
case IFA_CACHEINFO: {
const struct ifa_cacheinfo *cache_info =
reinterpret_cast<const struct ifa_cacheinfo*>(RTA_DATA(attr));
if (really_deprecated)
*really_deprecated = (cache_info->ifa_prefered == 0);
} break;
default:
break;
}
}
if (local)
address = local;
if (!address)
return false;
*out = IPAddress(address, address_length);
return true;
}
} // namespace
// static
char* AddressTrackerLinux::GetInterfaceName(int interface_index, char* buf) {
memset(buf, 0, IFNAMSIZ);
base::ScopedFD ioctl_socket = GetSocketForIoctl();
if (!ioctl_socket.is_valid())
return buf;
struct ifreq ifr = {};
ifr.ifr_ifindex = interface_index;
if (ioctl(ioctl_socket.get(), SIOCGIFNAME, &ifr) == 0)
strncpy(buf, ifr.ifr_name, IFNAMSIZ - 1);
return buf;
}
AddressTrackerLinux::AddressTrackerLinux()
: get_interface_name_(GetInterfaceName),
address_callback_(base::DoNothing()),
link_callback_(base::DoNothing()),
tunnel_callback_(base::DoNothing()),
netlink_fd_(-1),
watcher_(FROM_HERE),
ignored_interfaces_(),
connection_type_initialized_(false),
connection_type_initialized_cv_(&connection_type_lock_),
current_connection_type_(NetworkChangeNotifier::CONNECTION_NONE),
tracking_(false),
threads_waiting_for_connection_type_initialization_(0) {}
AddressTrackerLinux::AddressTrackerLinux(
const base::Closure& address_callback,
const base::Closure& link_callback,
const base::Closure& tunnel_callback,
const std::unordered_set<std::string>& ignored_interfaces)
: get_interface_name_(GetInterfaceName),
address_callback_(address_callback),
link_callback_(link_callback),
tunnel_callback_(tunnel_callback),
netlink_fd_(-1),
watcher_(FROM_HERE),
ignored_interfaces_(ignored_interfaces),
connection_type_initialized_(false),
connection_type_initialized_cv_(&connection_type_lock_),
current_connection_type_(NetworkChangeNotifier::CONNECTION_NONE),
tracking_(true),
threads_waiting_for_connection_type_initialization_(0) {
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;
}
int rv;
if (tracking_) {
// 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;
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;
bool tunnel_changed;
ReadMessages(&address_changed, &link_changed, &tunnel_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, &tunnel_changed);
{
AddressTrackerAutoLock lock(*this, connection_type_lock_);
connection_type_initialized_ = true;
connection_type_initialized_cv_.Broadcast();
}
if (tracking_) {
rv = base::MessageLoopCurrentForIO::Get()->WatchFileDescriptor(
netlink_fd_, true, base::MessagePumpForIO::WATCH_READ, &watcher_, this);
if (rv < 0) {
PLOG(ERROR) << "Could not watch NETLINK socket";
AbortAndForceOnline();
return;
}
}
}
void AddressTrackerLinux::AbortAndForceOnline() {
CloseSocket();
AddressTrackerAutoLock lock(*this, connection_type_lock_);
current_connection_type_ = NetworkChangeNotifier::CONNECTION_UNKNOWN;
connection_type_initialized_ = true;
connection_type_initialized_cv_.Broadcast();
}
AddressTrackerLinux::AddressMap AddressTrackerLinux::GetAddressMap() const {
AddressTrackerAutoLock lock(*this, address_map_lock_);
return address_map_;
}
std::unordered_set<int> AddressTrackerLinux::GetOnlineLinks() const {
AddressTrackerAutoLock lock(*this, online_links_lock_);
return online_links_;
}
bool AddressTrackerLinux::IsInterfaceIgnored(int interface_index) const {
if (ignored_interfaces_.empty())
return false;
char buf[IFNAMSIZ] = {0};
const char* interface_name = get_interface_name_(interface_index, buf);
return ignored_interfaces_.find(interface_name) != ignored_interfaces_.end();
}
NetworkChangeNotifier::ConnectionType
AddressTrackerLinux::GetCurrentConnectionType() {
// http://crbug.com/125097
base::ScopedAllowBaseSyncPrimitivesOutsideBlockingScope allow_wait;
AddressTrackerAutoLock lock(*this, connection_type_lock_);
// Make sure the initial connection type is set before returning.
threads_waiting_for_connection_type_initialization_++;
while (!connection_type_initialized_) {
connection_type_initialized_cv_.Wait();
}
threads_waiting_for_connection_type_initialization_--;
return current_connection_type_;
}
void AddressTrackerLinux::ReadMessages(bool* address_changed,
bool* link_changed,
bool* tunnel_changed) {
*address_changed = false;
*link_changed = false;
*tunnel_changed = false;
char buffer[4096];
bool first_loop = true;
{
base::Optional<base::ScopedBlockingCall> blocking_call;
if (tracking_) {
// If the loop below takes a long time to run, a new thread should added
// to the current thread pool to ensure forward progress of all tasks.
base::AssertBlockingAllowedDeprecated();
blocking_call.emplace(base::BlockingType::MAY_BLOCK);
}
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, tunnel_changed);
}
}
if (*link_changed || *address_changed)
UpdateCurrentConnectionType();
}
void AddressTrackerLinux::HandleMessage(char* buffer,
size_t length,
bool* address_changed,
bool* link_changed,
bool* tunnel_changed) {
DCHECK(buffer);
for (struct nlmsghdr* header = reinterpret_cast<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: {
IPAddress address;
bool really_deprecated;
struct ifaddrmsg* msg =
reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
if (IsInterfaceIgnored(msg->ifa_index))
break;
if (GetAddress(header, &address, &really_deprecated)) {
AddressTrackerAutoLock lock(*this, address_map_lock_);
// Routers may frequently (every few seconds) output the IPv6 ULA
// prefix which can cause the linux kernel to frequently output two
// back-to-back messages, one without the deprecated flag and one with
// the deprecated flag but both with preferred lifetimes of 0. Avoid
// interpretting this as an actual change by canonicalizing the two
// messages by setting the deprecated flag based on the preferred
// lifetime also. http://crbug.com/268042
if (really_deprecated)
msg->ifa_flags |= IFA_F_DEPRECATED;
// Only indicate change if the address is new or ifaddrmsg info has
// changed.
auto 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: {
IPAddress address;
const struct ifaddrmsg* msg =
reinterpret_cast<struct ifaddrmsg*>(NLMSG_DATA(header));
if (IsInterfaceIgnored(msg->ifa_index))
break;
if (GetAddress(header, &address, NULL)) {
AddressTrackerAutoLock lock(*this, 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 (IsInterfaceIgnored(msg->ifi_index))
break;
if (IgnoreWirelessChange(header, msg)) {
VLOG(2) << "Ignoring RTM_NEWLINK message";
break;
}
if (!(msg->ifi_flags & IFF_LOOPBACK) && (msg->ifi_flags & IFF_UP) &&
(msg->ifi_flags & IFF_LOWER_UP) && (msg->ifi_flags & IFF_RUNNING)) {
AddressTrackerAutoLock lock(*this, online_links_lock_);
if (online_links_.insert(msg->ifi_index).second) {
*link_changed = true;
if (IsTunnelInterface(msg->ifi_index))
*tunnel_changed = true;
}
} else {
AddressTrackerAutoLock lock(*this, online_links_lock_);
if (online_links_.erase(msg->ifi_index)) {
*link_changed = true;
if (IsTunnelInterface(msg->ifi_index))
*tunnel_changed = true;
}
}
} break;
case RTM_DELLINK: {
const struct ifinfomsg* msg =
reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
if (IsInterfaceIgnored(msg->ifi_index))
break;
AddressTrackerAutoLock lock(*this, online_links_lock_);
if (online_links_.erase(msg->ifi_index)) {
*link_changed = true;
if (IsTunnelInterface(msg->ifi_index))
*tunnel_changed = true;
}
} break;
default:
break;
}
}
}
void AddressTrackerLinux::OnFileCanReadWithoutBlocking(int fd) {
DCHECK_EQ(netlink_fd_, fd);
bool address_changed;
bool link_changed;
bool tunnel_changed;
ReadMessages(&address_changed, &link_changed, &tunnel_changed);
if (address_changed)
address_callback_.Run();
if (link_changed)
link_callback_.Run();
if (tunnel_changed)
tunnel_callback_.Run();
}
void AddressTrackerLinux::OnFileCanWriteWithoutBlocking(int /* fd */) {}
void AddressTrackerLinux::CloseSocket() {
if (netlink_fd_ >= 0 && IGNORE_EINTR(close(netlink_fd_)) < 0)
PLOG(ERROR) << "Could not close NETLINK socket.";
netlink_fd_ = -1;
}
bool AddressTrackerLinux::IsTunnelInterface(int interface_index) const {
char buf[IFNAMSIZ] = {0};
return IsTunnelInterfaceName(get_interface_name_(interface_index, buf));
}
// static
bool AddressTrackerLinux::IsTunnelInterfaceName(const char* name) {
// Linux kernel drivers/net/tun.c uses "tun" name prefix.
return strncmp(name, "tun", 3) == 0;
}
void AddressTrackerLinux::UpdateCurrentConnectionType() {
AddressTrackerLinux::AddressMap address_map = GetAddressMap();
std::unordered_set<int> online_links = GetOnlineLinks();
// Strip out tunnel interfaces from online_links
for (auto it = online_links.cbegin(); it != online_links.cend();) {
if (IsTunnelInterface(*it)) {
it = online_links.erase(it);
} else {
++it;
}
}
NetworkInterfaceList networks;
NetworkChangeNotifier::ConnectionType type =
NetworkChangeNotifier::CONNECTION_NONE;
if (GetNetworkListImpl(&networks, 0, online_links, address_map,
get_interface_name_)) {
type = NetworkChangeNotifier::ConnectionTypeFromInterfaceList(networks);
} else {
type = online_links.empty() ? NetworkChangeNotifier::CONNECTION_NONE
: NetworkChangeNotifier::CONNECTION_UNKNOWN;
}
AddressTrackerAutoLock lock(*this, connection_type_lock_);
current_connection_type_ = type;
}
int AddressTrackerLinux::GetThreadsWaitingForConnectionTypeInitForTesting()
{
AddressTrackerAutoLock lock(*this, connection_type_lock_);
return threads_waiting_for_connection_type_initialization_;
}
AddressTrackerLinux::AddressTrackerAutoLock::AddressTrackerAutoLock(
const AddressTrackerLinux& tracker,
base::Lock& lock)
: tracker_(tracker), lock_(lock) {
if (tracker_.tracking_) {
lock_.Acquire();
} else {
DCHECK(tracker_.thread_checker_.CalledOnValidThread());
}
}
AddressTrackerLinux::AddressTrackerAutoLock::~AddressTrackerAutoLock() {
if (tracker_.tracking_) {
lock_.AssertAcquired();
lock_.Release();
}
}
} // namespace internal
} // namespace net