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/** ---------------------------------------------------------------------------
Copyright (c) 2011, Code Aurora Forum. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
* Neither the name of Code Aurora Forum, Inc. nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-----------------------------------------------------------------------------**/
#include "host_resolver_helper.h"
#include <config.h>
#include <unistd.h>
#include "net/base/address_list.h"
#include "net/base/host_port_pair.h"
#include "net/base/completion_callback.h"
#include "net/base/host_port_pair.h"
#include "net/base/host_resolver.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
#include <cutils/properties.h>
#include "dyn_lib_loader.h"
#define NUM_HOSTS_TO_RESOLVE 30
HostResolverHelper::HostResolverHelper(net::HostResolver* hostresolver) :
num_of_hosts_to_resolve(NUM_HOSTS_TO_RESOLVE), hostresolver_(
hostresolver), hostname_provider_(NULL)
{
char value[PROPERTY_VALUE_MAX] = { '\0' };
property_get("net.dnshostprio.num_hosts", value, NULL);
if (NULL != value && value[0] != '\0') {
int host_num = atol(value);
if (host_num <= 0) {
host_num = NUM_HOSTS_TO_RESOLVE;
}
num_of_hosts_to_resolve = host_num;
}
}
HostResolverHelper::~HostResolverHelper() {
}
void HostResolverHelper::Init(HostsProvider* provider) {
hostname_provider_ = provider;
LOG(INFO) << "DNSPreResolver::Init got hostprovider:" << provider;
if (hostresolver_)
hostresolver_->SetResolverExt(this);
}
void HostResolverHelper::DoResolve(HostResolverHelper* obj) {
//TODO: Check there is another task like this in the queue and
// skip execution of the current one
obj->StartHostsResolution();
}
void HostResolverHelper::CancelAllRequests() {
//loop through all requests and cancel those that still pending
for (unsigned int i = 0; i < hostinfo_list_.size(); i++) {
if (hostinfo_list_[i]->pending) {
hostinfo_list_[i]->pending = false;
hostresolver_->CancelRequest(hostinfo_list_[i]->reqhandle);
}
}
}
void HostResolverHelper::PrepareRequestsData(const std::vector<std::string>& hostnames) {
const int actual_hosts_num = hostnames.size();
hostinfo_list_.clear();
hostinfo_list_.reserve(actual_hosts_num);
for (int i = 0; i < actual_hosts_num; i++) {
hostinfo_list_.push_back(new HostInfo(hostnames[i].c_str()));
}
}
bool HostResolverHelper::StartHostsResolution() {
if (NULL == hostresolver_) {
return false;
}
if (NULL == hostname_provider_) {
return false;
}
//get hosts from the provider
std::vector < std::string > hostnames;
hostname_provider_->GetHosts(num_of_hosts_to_resolve, hostnames);
if (0 == hostnames.size()) {
return true;
}
//free old requests if any still active
CancelAllRequests();
PrepareRequestsData(hostnames);
const int actual_hosts_num = hostnames.size();
//now issue resolve for each host
for (int i = 0; i < actual_hosts_num; i++) {
//TODO: set request priority
hostinfo_list_[i]->pending = true;
int rv = hostresolver_->Resolve(hostinfo_list_[i]->reqinfo, &hostinfo_list_[i]->addrlist,
&hostinfo_list_[i]->completion_callback_, &hostinfo_list_[i]->reqhandle, net::BoundNetLog());
//in case we got it resolved synchronously (or error) - set as not pending
if (rv != net::ERR_IO_PENDING) {
hostinfo_list_[i]->pending = false;
}
}
return true;
}
void HostResolverHelper::HostInfo::OnLookupFinished(int result) {
pending = false;
}
HostResolverHelper::HostInfo::HostInfo(const std::string& hostname) :
reqinfo(net::HostPortPair(hostname, 80)), reqhandle(NULL), pending(false), completion_callback_(this,
&HostInfo::OnLookupFinished) {
}
net::HostResolver::HostnameResolverExt* CreateResolverIPObserver(net::HostResolver* hostResolver) {
char value[PROPERTY_VALUE_MAX] = { '\0' };
const char* DNS_PRIORITY_EXTERNAL_LIB = "libdnshostprio.so";
if (NULL == hostResolver) {
return NULL;
}
property_get("net.dnshostprio.enable", value, NULL);
if (NULL != value && value[0] == '0') {
return NULL;
}
HostResolverHelper* dnsPreresolver = new HostResolverHelper(hostResolver);
if (NULL == dnsPreresolver) {
return NULL;
}
HostsProvider* provider = GET_DYNAMIC_OBJECT_INTERFACE_PTR(DNS_PRIORITY_EXTERNAL_LIB,HostsProvider);
dnsPreresolver->Init(provider);
return dnsPreresolver;
}
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