blob: 3cee3b5e49262e66497fdc738d0204805f16533c [file] [log] [blame]
// Copyright (c) 2012 The Chromium OS 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 "shill/routing_table.h"
#include <arpa/inet.h>
#include <fcntl.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <netinet/ether.h>
#include <net/if.h> // NOLINT - must be included after netinet/ether.h
#include <net/if_arp.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>
#include <unistd.h>
#include <memory>
#include <string>
#include <base/bind.h>
#include <base/files/file_path.h>
#include <base/files/file_util.h>
#include <base/stl_util.h>
#include <base/strings/stringprintf.h>
#include "shill/ipconfig.h"
#include "shill/logging.h"
#include "shill/net/byte_string.h"
#include "shill/net/rtnl_handler.h"
#include "shill/net/rtnl_listener.h"
#include "shill/net/rtnl_message.h"
#include "shill/routing_table_entry.h"
using base::Bind;
using base::FilePath;
using base::Unretained;
using std::deque;
using std::string;
using std::vector;
namespace shill {
namespace Logging {
static auto kModuleLogScope = ScopeLogger::kRoute;
static string ObjectID(RoutingTable* r) { return "(routing_table)"; }
}
namespace {
base::LazyInstance<RoutingTable> g_routing_table = LAZY_INSTANCE_INITIALIZER;
} // namespace
// static
const char RoutingTable::kRouteFlushPath4[] = "/proc/sys/net/ipv4/route/flush";
// static
const char RoutingTable::kRouteFlushPath6[] = "/proc/sys/net/ipv6/route/flush";
RoutingTable::RoutingTable()
: route_callback_(Bind(&RoutingTable::RouteMsgHandler, Unretained(this))),
rtnl_handler_(RTNLHandler::GetInstance()) {
SLOG(this, 2) << __func__;
}
RoutingTable::~RoutingTable() {}
RoutingTable* RoutingTable::GetInstance() {
return g_routing_table.Pointer();
}
void RoutingTable::Start() {
SLOG(this, 2) << __func__;
route_listener_.reset(
new RTNLListener(RTNLHandler::kRequestRoute, route_callback_));
rtnl_handler_->RequestDump(RTNLHandler::kRequestRoute);
}
void RoutingTable::Stop() {
SLOG(this, 2) << __func__;
route_listener_.reset();
}
bool RoutingTable::AddRoute(int interface_index,
const RoutingTableEntry& entry) {
SLOG(this, 2) << __func__ << ": "
<< "destination " << entry.dst.ToString()
<< " index " << interface_index
<< " gateway " << entry.gateway.ToString()
<< " metric " << entry.metric;
CHECK(!entry.from_rtnl);
if (!ApplyRoute(interface_index,
entry,
RTNLMessage::kModeAdd,
NLM_F_CREATE | NLM_F_EXCL)) {
return false;
}
tables_[interface_index].push_back(entry);
return true;
}
bool RoutingTable::GetDefaultRoute(int interface_index,
IPAddress::Family family,
RoutingTableEntry* entry) {
RoutingTableEntry* found_entry;
bool ret = GetDefaultRouteInternal(interface_index, family, &found_entry);
if (ret) {
*entry = *found_entry;
}
return ret;
}
bool RoutingTable::GetDefaultRouteInternal(int interface_index,
IPAddress::Family family,
RoutingTableEntry** entry) {
SLOG(this, 2) << __func__ << " index " << interface_index
<< " family " << IPAddress::GetAddressFamilyName(family);
Tables::iterator table = tables_.find(interface_index);
if (table == tables_.end()) {
SLOG(this, 2) << __func__ << " no table";
return false;
}
for (auto& nent : table->second) {
if (nent.dst.IsDefault() && nent.dst.family() == family) {
*entry = &nent;
SLOG(this, 2) << __func__ << ": found"
<< " gateway " << nent.gateway.ToString()
<< " metric " << nent.metric;
return true;
}
}
SLOG(this, 2) << __func__ << " no route";
return false;
}
bool RoutingTable::SetDefaultRoute(int interface_index,
const IPAddress& gateway_address,
uint32_t metric,
uint8_t table_id) {
SLOG(this, 2) << __func__ << " index " << interface_index
<< " metric " << metric;
RoutingTableEntry* old_entry;
if (GetDefaultRouteInternal(interface_index,
gateway_address.family(),
&old_entry)) {
if (old_entry->gateway.Equals(gateway_address)) {
if (old_entry->metric != metric) {
ReplaceMetric(interface_index, old_entry, metric);
}
return true;
} else {
// TODO(quiche): Update internal state as well?
ApplyRoute(interface_index,
*old_entry,
RTNLMessage::kModeDelete,
0);
}
}
IPAddress default_address(gateway_address.family());
default_address.SetAddressToDefault();
return AddRoute(interface_index,
RoutingTableEntry(default_address,
default_address,
gateway_address,
metric,
RT_SCOPE_UNIVERSE,
false,
table_id,
RoutingTableEntry::kDefaultTag));
}
bool RoutingTable::ConfigureRoutes(int interface_index,
const IPConfigRefPtr& ipconfig,
uint32_t metric,
uint8_t table_id) {
bool ret = true;
IPAddress::Family address_family = ipconfig->properties().address_family;
const vector<IPConfig::Route>& routes = ipconfig->properties().routes;
for (const auto& route : routes) {
SLOG(this, 3) << "Installing route:"
<< " Destination: " << route.host
<< " Netmask: " << route.netmask
<< " Gateway: " << route.gateway;
IPAddress destination_address(address_family);
IPAddress source_address(address_family); // Left as default.
IPAddress gateway_address(address_family);
if (!destination_address.SetAddressFromString(route.host)) {
LOG(ERROR) << "Failed to parse host "
<< route.host;
ret = false;
continue;
}
if (!gateway_address.SetAddressFromString(route.gateway)) {
LOG(ERROR) << "Failed to parse gateway "
<< route.gateway;
ret = false;
continue;
}
destination_address.set_prefix(
IPAddress::GetPrefixLengthFromMask(address_family, route.netmask));
if (!AddRoute(interface_index,
RoutingTableEntry(destination_address,
source_address,
gateway_address,
metric,
RT_SCOPE_UNIVERSE,
false,
table_id,
RoutingTableEntry::kDefaultTag))) {
ret = false;
}
}
return ret;
}
void RoutingTable::FlushRoutes(int interface_index) {
SLOG(this, 2) << __func__;
auto table = tables_.find(interface_index);
if (table == tables_.end()) {
return;
}
for (const auto& nent : table->second) {
ApplyRoute(interface_index, nent, RTNLMessage::kModeDelete, 0);
}
table->second.clear();
}
void RoutingTable::FlushRoutesWithTag(int tag) {
SLOG(this, 2) << __func__;
for (auto& table : tables_) {
for (auto nent = table.second.begin(); nent != table.second.end();) {
if (nent->tag == tag) {
ApplyRoute(table.first, *nent, RTNLMessage::kModeDelete, 0);
nent = table.second.erase(nent);
} else {
++nent;
}
}
}
}
void RoutingTable::ResetTable(int interface_index) {
tables_.erase(interface_index);
}
void RoutingTable::SetDefaultMetric(int interface_index, uint32_t metric) {
SLOG(this, 2) << __func__ << " index " << interface_index
<< " metric " << metric;
RoutingTableEntry* entry;
if (GetDefaultRouteInternal(
interface_index, IPAddress::kFamilyIPv4, &entry) &&
entry->metric != metric) {
ReplaceMetric(interface_index, entry, metric);
}
if (GetDefaultRouteInternal(
interface_index, IPAddress::kFamilyIPv6, &entry) &&
entry->metric != metric) {
ReplaceMetric(interface_index, entry, metric);
}
}
// static
bool RoutingTable::ParseRoutingTableMessage(const RTNLMessage& message,
int* interface_index,
RoutingTableEntry* entry) {
if (message.type() != RTNLMessage::kTypeRoute ||
message.family() == IPAddress::kFamilyUnknown ||
!message.HasAttribute(RTA_OIF)) {
return false;
}
const RTNLMessage::RouteStatus& route_status = message.route_status();
if (route_status.type != RTN_UNICAST) {
return false;
}
uint32_t interface_index_u32 = 0;
if (!message.GetAttribute(RTA_OIF).ConvertToCPUUInt32(&interface_index_u32)) {
return false;
}
*interface_index = interface_index_u32;
uint32_t metric = 0;
if (message.HasAttribute(RTA_PRIORITY)) {
message.GetAttribute(RTA_PRIORITY).ConvertToCPUUInt32(&metric);
}
IPAddress default_addr(message.family());
default_addr.SetAddressToDefault();
ByteString dst_bytes(default_addr.address());
if (message.HasAttribute(RTA_DST)) {
dst_bytes = message.GetAttribute(RTA_DST);
}
ByteString src_bytes(default_addr.address());
if (message.HasAttribute(RTA_SRC)) {
src_bytes = message.GetAttribute(RTA_SRC);
}
ByteString gateway_bytes(default_addr.address());
if (message.HasAttribute(RTA_GATEWAY)) {
gateway_bytes = message.GetAttribute(RTA_GATEWAY);
}
entry->dst = IPAddress(message.family(), dst_bytes, route_status.dst_prefix);
entry->src = IPAddress(message.family(), src_bytes, route_status.src_prefix);
entry->gateway = IPAddress(message.family(), gateway_bytes);
entry->metric = metric;
entry->scope = route_status.scope;
entry->from_rtnl = true;
entry->table = route_status.table;
return true;
}
void RoutingTable::RouteMsgHandler(const RTNLMessage& message) {
int interface_index;
RoutingTableEntry entry;
if (!ParseRoutingTableMessage(message, &interface_index, &entry)) {
return;
}
if (!route_queries_.empty() &&
message.route_status().protocol == RTPROT_UNSPEC) {
SLOG(this, 3) << __func__ << ": Message seq: " << message.seq()
<< " mode " << message.mode()
<< ", next query seq: " << route_queries_.front().sequence;
// Purge queries that have expired (sequence number of this message is
// greater than that of the head of the route query sequence). Do the
// math in a way that's roll-over independent.
while (route_queries_.front().sequence - message.seq() > kuint32max / 2) {
LOG(ERROR) << __func__ << ": Purging un-replied route request sequence "
<< route_queries_.front().sequence
<< " (< " << message.seq() << ")";
route_queries_.pop_front();
if (route_queries_.empty())
return;
}
const Query& query = route_queries_.front();
if (query.sequence == message.seq()) {
RoutingTableEntry add_entry(entry);
add_entry.from_rtnl = false;
add_entry.tag = query.tag;
add_entry.table = query.table_id;
bool added = true;
if (add_entry.gateway.IsDefault()) {
SLOG(this, 2) << __func__ << ": Ignoring route result with no gateway "
<< "since we don't need to plumb these.";
} else {
SLOG(this, 2) << __func__ << ": Adding host route to "
<< add_entry.dst.ToString();
added = AddRoute(interface_index, add_entry);
}
if (added && !query.callback.is_null()) {
SLOG(this, 2) << "Running query callback.";
query.callback.Run(interface_index, add_entry);
}
route_queries_.pop_front();
}
return;
} else if (message.route_status().protocol != RTPROT_BOOT) {
// Responses to route queries come back with a protocol of
// RTPROT_UNSPEC. Otherwise, normal route updates that we are
// interested in come with a protocol of RTPROT_BOOT.
return;
}
TableEntryVector& table = tables_[interface_index];
for (auto nent = table.begin(); nent != table.end(); ++nent) {
if (nent->dst.Equals(entry.dst) &&
nent->src.Equals(entry.src) &&
nent->gateway.Equals(entry.gateway) &&
nent->scope == entry.scope) {
if (message.mode() == RTNLMessage::kModeDelete &&
nent->metric == entry.metric) {
table.erase(nent);
} else if (message.mode() == RTNLMessage::kModeAdd) {
nent->from_rtnl = true;
nent->metric = entry.metric;
}
return;
}
}
if (message.mode() == RTNLMessage::kModeAdd) {
SLOG(this, 2) << __func__ << " adding"
<< " destination " << entry.dst.ToString()
<< " index " << interface_index
<< " gateway " << entry.gateway.ToString()
<< " metric " << entry.metric;
table.push_back(entry);
}
}
bool RoutingTable::ApplyRoute(uint32_t interface_index,
const RoutingTableEntry& entry,
RTNLMessage::Mode mode,
unsigned int flags) {
SLOG(this, 2) << base::StringPrintf(
"%s: dst %s/%d src %s/%d index %d mode %d flags 0x%x",
__func__, entry.dst.ToString().c_str(), entry.dst.prefix(),
entry.src.ToString().c_str(), entry.src.prefix(),
interface_index, mode, flags);
RTNLMessage message(
RTNLMessage::kTypeRoute,
mode,
NLM_F_REQUEST | flags,
0,
0,
0,
entry.dst.family());
message.set_route_status(RTNLMessage::RouteStatus(
entry.dst.prefix(),
entry.src.prefix(),
entry.table,
RTPROT_BOOT,
entry.scope,
RTN_UNICAST,
0));
message.SetAttribute(RTA_DST, entry.dst.address());
if (!entry.src.IsDefault()) {
message.SetAttribute(RTA_SRC, entry.src.address());
}
if (!entry.gateway.IsDefault()) {
message.SetAttribute(RTA_GATEWAY, entry.gateway.address());
}
message.SetAttribute(RTA_PRIORITY,
ByteString::CreateFromCPUUInt32(entry.metric));
message.SetAttribute(RTA_OIF,
ByteString::CreateFromCPUUInt32(interface_index));
return rtnl_handler_->SendMessage(&message);
}
// Somewhat surprisingly, the kernel allows you to create multiple routes
// to the same destination through the same interface with different metrics.
// Therefore, to change the metric on a route, we can't just use the
// NLM_F_REPLACE flag by itself. We have to explicitly remove the old route.
// We do so after creating the route at a new metric so there is no traffic
// disruption to existing network streams.
void RoutingTable::ReplaceMetric(uint32_t interface_index,
RoutingTableEntry* entry,
uint32_t metric) {
SLOG(this, 2) << __func__ << " index " << interface_index
<< " metric " << metric;
RoutingTableEntry new_entry = *entry;
new_entry.metric = metric;
// First create the route at the new metric.
ApplyRoute(interface_index, new_entry, RTNLMessage::kModeAdd,
NLM_F_CREATE | NLM_F_REPLACE);
// Then delete the route at the old metric.
ApplyRoute(interface_index, *entry, RTNLMessage::kModeDelete, 0);
// Now, update our routing table (via |*entry|) from |new_entry|.
*entry = new_entry;
}
bool RoutingTable::FlushCache() {
static const char* kPaths[2] = { kRouteFlushPath4, kRouteFlushPath6 };
bool ret = true;
SLOG(this, 2) << __func__;
for (size_t i = 0; i < arraysize(kPaths); ++i) {
if (base::WriteFile(FilePath(kPaths[i]), "-1", 2) != 2) {
LOG(ERROR) << base::StringPrintf("Cannot write to route flush file %s",
kPaths[i]);
ret = false;
}
}
return ret;
}
bool RoutingTable::RequestRouteToHost(const IPAddress& address,
int interface_index,
int tag,
const Query::Callback& callback,
uint8_t table_id) {
// Make sure we don't get a cached response that is no longer valid.
FlushCache();
RTNLMessage message(
RTNLMessage::kTypeRoute,
RTNLMessage::kModeQuery,
NLM_F_REQUEST,
0,
0,
interface_index,
address.family());
RTNLMessage::RouteStatus status;
status.dst_prefix = address.prefix();
message.set_route_status(status);
message.SetAttribute(RTA_DST, address.address());
if (interface_index != -1) {
message.SetAttribute(RTA_OIF,
ByteString::CreateFromCPUUInt32(interface_index));
}
if (!rtnl_handler_->SendMessage(&message)) {
return false;
}
// Save the sequence number of the request so we can create a route for
// this host when we get a reply.
route_queries_.push_back(Query(message.seq(), tag, callback, table_id));
return true;
}
bool RoutingTable::CreateBlackholeRoute(int interface_index,
IPAddress::Family family,
uint32_t metric,
uint8_t table_id) {
SLOG(this, 2) << base::StringPrintf(
"%s: index %d family %s metric %d",
__func__, interface_index,
IPAddress::GetAddressFamilyName(family).c_str(), metric);
RTNLMessage message(
RTNLMessage::kTypeRoute,
RTNLMessage::kModeAdd,
NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL,
0,
0,
0,
family);
message.set_route_status(RTNLMessage::RouteStatus(
0,
0,
table_id,
RTPROT_BOOT,
RT_SCOPE_UNIVERSE,
RTN_BLACKHOLE,
0));
message.SetAttribute(RTA_PRIORITY,
ByteString::CreateFromCPUUInt32(metric));
message.SetAttribute(RTA_OIF,
ByteString::CreateFromCPUUInt32(interface_index));
return rtnl_handler_->SendMessage(&message);
}
bool RoutingTable::CreateLinkRoute(int interface_index,
const IPAddress& local_address,
const IPAddress& remote_address,
uint8_t table_id) {
if (!local_address.CanReachAddress(remote_address)) {
LOG(ERROR) << __func__ << " failed: "
<< remote_address.ToString() << " is not reachable from "
<< local_address.ToString();
return false;
}
IPAddress default_address(local_address.family());
default_address.SetAddressToDefault();
IPAddress destination_address(remote_address);
destination_address.set_prefix(
IPAddress::GetMaxPrefixLength(remote_address.family()));
SLOG(this, 2) << "Creating link route to " << destination_address.ToString()
<< " from " << local_address.ToString()
<< " on interface index " << interface_index;
return AddRoute(interface_index,
RoutingTableEntry(destination_address,
local_address,
default_address,
0,
RT_SCOPE_LINK,
false,
table_id,
RoutingTableEntry::kDefaultTag));
}
} // namespace shill