gecko/netwerk/base/src/nsIOService.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set ts=4 sw=4 cindent et: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/DebugOnly.h"

#include "nsIOService.h"
#include "nsIProtocolHandler.h"
#include "nsIFileProtocolHandler.h"
#include "nscore.h"
#include "nsIURI.h"
#include "prprf.h"
#include "nsIErrorService.h"
#include "netCore.h"
#include "nsIObserverService.h"
#include "nsIPrefService.h"
#include "nsXPCOM.h"
#include "nsIProxiedProtocolHandler.h"
#include "nsIProxyInfo.h"
#include "nsEscape.h"
#include "nsNetCID.h"
#include "nsCRT.h"
#include "nsSimpleNestedURI.h"
#include "nsNetUtil.h"
#include "nsTArray.h"
#include "nsIConsoleService.h"
#include "nsIUploadChannel2.h"
#include "nsXULAppAPI.h"
#include "nsIProtocolProxyCallback.h"
#include "nsICancelable.h"
#include "nsINetworkLinkService.h"
#include "nsPISocketTransportService.h"
#include "nsAsyncRedirectVerifyHelper.h"
#include "nsURLHelper.h"
#include "nsPIDNSService.h"
#include "nsIProtocolProxyService2.h"
#include "MainThreadUtils.h"
#include "nsIWidget.h"

#if defined(XP_WIN)
#include "nsNativeConnectionHelper.h"
#endif

using namespace mozilla;

#define PORT_PREF_PREFIX           "network.security.ports."
#define PORT_PREF(x)               PORT_PREF_PREFIX x
#define AUTODIAL_PREF              "network.autodial-helper.enabled"
#define MANAGE_OFFLINE_STATUS_PREF "network.manage-offline-status"

// Nb: these have been misnomers since bug 715770 removed the buffer cache.
// "network.segment.count" and "network.segment.size" would be better names,
// but the old names are still used to preserve backward compatibility.
#define NECKO_BUFFER_CACHE_COUNT_PREF "network.buffer.cache.count"
#define NECKO_BUFFER_CACHE_SIZE_PREF  "network.buffer.cache.size"
#define NETWORK_NOTIFY_CHANGED_PREF   "network.notify.changed"

#define MAX_RECURSION_COUNT 50

nsIOService* gIOService = nullptr;
static bool gHasWarnedUploadChannel2;

// A general port blacklist.  Connections to these ports will not be allowed
// unless the protocol overrides.
//
// TODO: I am sure that there are more ports to be added.  
//       This cut is based on the classic mozilla codebase

int16_t gBadPortList[] = { 
  1,    // tcpmux          
  7,    // echo     
  9,    // discard          
  11,   // systat   
  13,   // daytime          
  15,   // netstat  
  17,   // qotd             
  19,   // chargen  
  20,   // ftp-data         
  21,   // ftp-cntl 
  22,   // ssh              
  23,   // telnet   
  25,   // smtp     
  37,   // time     
  42,   // name     
  43,   // nicname  
  53,   // domain  
  77,   // priv-rjs 
  79,   // finger   
  87,   // ttylink  
  95,   // supdup   
  101,  // hostriame
  102,  // iso-tsap 
  103,  // gppitnp  
  104,  // acr-nema 
  109,  // pop2     
  110,  // pop3     
  111,  // sunrpc   
  113,  // auth     
  115,  // sftp     
  117,  // uucp-path
  119,  // nntp     
  123,  // NTP
  135,  // loc-srv / epmap         
  139,  // netbios
  143,  // imap2  
  179,  // BGP
  389,  // ldap        
  465,  // smtp+ssl
  512,  // print / exec          
  513,  // login         
  514,  // shell         
  515,  // printer         
  526,  // tempo         
  530,  // courier        
  531,  // Chat         
  532,  // netnews        
  540,  // uucp       
  556,  // remotefs    
  563,  // nntp+ssl
  587,  //
  601,  //       
  636,  // ldap+ssl
  993,  // imap+ssl
  995,  // pop3+ssl
  2049, // nfs
  4045, // lockd
  6000, // x11        
  0,    // This MUST be zero so that we can populating the array
};

static const char kProfileChangeNetTeardownTopic[] = "profile-change-net-teardown";
static const char kProfileChangeNetRestoreTopic[] = "profile-change-net-restore";
static const char kProfileDoChange[] = "profile-do-change";

// Necko buffer defaults
uint32_t   nsIOService::gDefaultSegmentSize = 4096;
uint32_t   nsIOService::gDefaultSegmentCount = 24;

////////////////////////////////////////////////////////////////////////////////

nsIOService::nsIOService()
    : mOffline(true)
    , mOfflineForProfileChange(false)
    , mManageOfflineStatus(false)
    , mSettingOffline(false)
    , mSetOfflineValue(false)
    , mShutdown(false)
    , mNetworkLinkServiceInitialized(false)
    , mChannelEventSinks(NS_CHANNEL_EVENT_SINK_CATEGORY)
    , mAutoDialEnabled(false)
    , mNetworkNotifyChanged(true)
{
}

nsresult
nsIOService::Init()
{
    nsresult rv;

    // We need to get references to the DNS service so that we can shut it
    // down later. If we wait until the nsIOService is being shut down,
    // GetService will fail at that point.

    mDNSService = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
    if (NS_FAILED(rv)) {
        NS_WARNING("failed to get DNS service");
        return rv;
    }

    // XXX hack until xpidl supports error info directly (bug 13423)
    nsCOMPtr<nsIErrorService> errorService = do_GetService(NS_ERRORSERVICE_CONTRACTID);
    if (errorService) {
        errorService->RegisterErrorStringBundle(NS_ERROR_MODULE_NETWORK, NECKO_MSGS_URL);
    }
    else
        NS_WARNING("failed to get error service");
    
    // setup our bad port list stuff
    for(int i=0; gBadPortList[i]; i++)
        mRestrictedPortList.AppendElement(gBadPortList[i]);

    // Further modifications to the port list come from prefs
    nsCOMPtr<nsIPrefBranch> prefBranch;
    GetPrefBranch(getter_AddRefs(prefBranch));
    if (prefBranch) {
        prefBranch->AddObserver(PORT_PREF_PREFIX, this, true);
        prefBranch->AddObserver(AUTODIAL_PREF, this, true);
        prefBranch->AddObserver(MANAGE_OFFLINE_STATUS_PREF, this, true);
        prefBranch->AddObserver(NECKO_BUFFER_CACHE_COUNT_PREF, this, true);
        prefBranch->AddObserver(NECKO_BUFFER_CACHE_SIZE_PREF, this, true);
        prefBranch->AddObserver(NETWORK_NOTIFY_CHANGED_PREF, this, true);
        PrefsChanged(prefBranch);
    }
    
    // Register for profile change notifications
    nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();
    if (observerService) {
        observerService->AddObserver(this, kProfileChangeNetTeardownTopic, true);
        observerService->AddObserver(this, kProfileChangeNetRestoreTopic, true);
        observerService->AddObserver(this, kProfileDoChange, true);
        observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, true);
        observerService->AddObserver(this, NS_NETWORK_LINK_TOPIC, true);
        observerService->AddObserver(this, NS_WIDGET_WAKE_OBSERVER_TOPIC, true);
    }
    else
        NS_WARNING("failed to get observer service");

    gIOService = this;

    InitializeNetworkLinkService();

    return NS_OK;
}


nsIOService::~nsIOService()
{
    gIOService = nullptr;
}

nsresult
nsIOService::InitializeSocketTransportService()
{
    nsresult rv = NS_OK;

    if (!mSocketTransportService) {
        mSocketTransportService = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID, &rv);
        if (NS_FAILED(rv)) {
            NS_WARNING("failed to get socket transport service");
        }
    }

    if (mSocketTransportService) {
        rv = mSocketTransportService->Init();
        NS_ASSERTION(NS_SUCCEEDED(rv), "socket transport service init failed");
        mSocketTransportService->SetAutodialEnabled(mAutoDialEnabled);
        mSocketTransportService->SetOffline(false);
    }

    return rv;
}

nsresult
nsIOService::InitializeNetworkLinkService()
{
    nsresult rv = NS_OK;

    if (mNetworkLinkServiceInitialized)
        return rv;

    if (!NS_IsMainThread()) {
        NS_WARNING("Network link service should be created on main thread"); 
        return NS_ERROR_FAILURE; 
    }

    // go into managed mode if we can, and chrome process
    if (XRE_GetProcessType() == GeckoProcessType_Default)
    {
        mNetworkLinkService = do_GetService(NS_NETWORK_LINK_SERVICE_CONTRACTID, &rv);
    }

    if (mNetworkLinkService) {
        mNetworkLinkServiceInitialized = true;
    }
    else {
        // We can't really determine if the machine has a usable network connection,
        // so let's cross our fingers!
        mManageOfflineStatus = false;
    }

    if (mManageOfflineStatus)
        OnNetworkLinkEvent(NS_NETWORK_LINK_DATA_UNKNOWN);
    else
        SetOffline(false);
    
    return rv;
}

nsIOService*
nsIOService::GetInstance() {
    if (!gIOService) {
        gIOService = new nsIOService();
        if (!gIOService)
            return nullptr;
        NS_ADDREF(gIOService);

        nsresult rv = gIOService->Init();
        if (NS_FAILED(rv)) {
            NS_RELEASE(gIOService);
            return nullptr;
        }
        return gIOService;
    }
    NS_ADDREF(gIOService);
    return gIOService;
}

NS_IMPL_ISUPPORTS(nsIOService,
                  nsIIOService,
                  nsIIOService2,
                  nsINetUtil,
                  nsISpeculativeConnect,
                  nsIObserver,
                  nsISupportsWeakReference)

////////////////////////////////////////////////////////////////////////////////

nsresult
nsIOService::AsyncOnChannelRedirect(nsIChannel* oldChan, nsIChannel* newChan,
                                    uint32_t flags,
                                    nsAsyncRedirectVerifyHelper *helper)
{
    nsCOMPtr<nsIChannelEventSink> sink =
        do_GetService(NS_GLOBAL_CHANNELEVENTSINK_CONTRACTID);
    if (sink) {
        nsresult rv = helper->DelegateOnChannelRedirect(sink, oldChan,
                                                        newChan, flags);
        if (NS_FAILED(rv))
            return rv;
    }

    // Finally, our category
    nsCOMArray<nsIChannelEventSink> entries;
    mChannelEventSinks.GetEntries(entries);
    int32_t len = entries.Count();
    for (int32_t i = 0; i < len; ++i) {
        nsresult rv = helper->DelegateOnChannelRedirect(entries[i], oldChan,
                                                        newChan, flags);
        if (NS_FAILED(rv))
            return rv;
    }
    return NS_OK;
}

nsresult
nsIOService::CacheProtocolHandler(const char *scheme, nsIProtocolHandler *handler)
{
    for (unsigned int i=0; i<NS_N(gScheme); i++)
    {
        if (!nsCRT::strcasecmp(scheme, gScheme[i]))
        {
            nsresult rv;
            NS_ASSERTION(!mWeakHandler[i], "Protocol handler already cached");
            // Make sure the handler supports weak references.
            nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(handler, &rv);
            if (!factoryPtr)
            {
                // Don't cache handlers that don't support weak reference as
                // there is real danger of a circular reference.
#ifdef DEBUG_dp
                printf("DEBUG: %s protcol handler doesn't support weak ref. Not cached.\n", scheme);
#endif /* DEBUG_dp */
                return NS_ERROR_FAILURE;
            }
            mWeakHandler[i] = do_GetWeakReference(handler);
            return NS_OK;
        }
    }
    return NS_ERROR_FAILURE;
}

nsresult
nsIOService::GetCachedProtocolHandler(const char *scheme, nsIProtocolHandler **result, uint32_t start, uint32_t end)
{
    uint32_t len = end - start - 1;
    for (unsigned int i=0; i<NS_N(gScheme); i++)
    {
        if (!mWeakHandler[i])
            continue;

        // handle unterminated strings
        // start is inclusive, end is exclusive, len = end - start - 1
        if (end ? (!nsCRT::strncasecmp(scheme + start, gScheme[i], len)
                   && gScheme[i][len] == '\0')
                : (!nsCRT::strcasecmp(scheme, gScheme[i])))
        {
            return CallQueryReferent(mWeakHandler[i].get(), result);
        }
    }
    return NS_ERROR_FAILURE;
}
 
NS_IMETHODIMP
nsIOService::GetProtocolHandler(const char* scheme, nsIProtocolHandler* *result)
{
    nsresult rv;

    NS_ENSURE_ARG_POINTER(scheme);
    // XXX we may want to speed this up by introducing our own protocol 
    // scheme -> protocol handler mapping, avoiding the string manipulation
    // and service manager stuff

    rv = GetCachedProtocolHandler(scheme, result);
    if (NS_SUCCEEDED(rv))
        return rv;

    bool externalProtocol = false;
    nsCOMPtr<nsIPrefBranch> prefBranch;
    GetPrefBranch(getter_AddRefs(prefBranch));
    if (prefBranch) {
        nsAutoCString externalProtocolPref("network.protocol-handler.external.");
        externalProtocolPref += scheme;
        rv = prefBranch->GetBoolPref(externalProtocolPref.get(), &externalProtocol);
        if (NS_FAILED(rv)) {
            externalProtocol = false;
        }
    }

    if (!externalProtocol) {
        nsAutoCString contractID(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX);
        contractID += scheme;
        ToLowerCase(contractID);

        rv = CallGetService(contractID.get(), result);
        if (NS_SUCCEEDED(rv)) {
            CacheProtocolHandler(scheme, *result);
            return rv;
        }

#ifdef MOZ_X11
        // check to see whether GVFS can handle this URI scheme.  if it can
        // create a nsIURI for the "scheme:", then we assume it has support for
        // the requested protocol.  otherwise, we failover to using the default
        // protocol handler.

        rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"moz-gio",
                            result);
        if (NS_SUCCEEDED(rv)) {
            nsAutoCString spec(scheme);
            spec.Append(':');

            nsIURI *uri;
            rv = (*result)->NewURI(spec, nullptr, nullptr, &uri);
            if (NS_SUCCEEDED(rv)) {
                NS_RELEASE(uri);
                return rv;
            }

            NS_RELEASE(*result);
        }

        // check to see whether GnomeVFS can handle this URI scheme.  if it can
        // create a nsIURI for the "scheme:", then we assume it has support for
        // the requested protocol.  otherwise, we failover to using the default
        // protocol handler.

        // XXX should this be generalized into something that searches a
        // category?  (see bug 234714)

        rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"moz-gnomevfs",
                            result);
        if (NS_SUCCEEDED(rv)) {
            nsAutoCString spec(scheme);
            spec.Append(':');

            nsIURI *uri;
            rv = (*result)->NewURI(spec, nullptr, nullptr, &uri);
            if (NS_SUCCEEDED(rv)) {
                NS_RELEASE(uri);
                return rv;
            }

            NS_RELEASE(*result);
        }
#endif
    }

    // Okay we don't have a protocol handler to handle this url type, so use
    // the default protocol handler.  This will cause urls to get dispatched
    // out to the OS ('cause we can't do anything with them) when we try to
    // read from a channel created by the default protocol handler.

    rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"default",
                        result);
    if (NS_FAILED(rv))
        return NS_ERROR_UNKNOWN_PROTOCOL;

    return rv;
}

NS_IMETHODIMP
nsIOService::ExtractScheme(const nsACString &inURI, nsACString &scheme)
{
    return net_ExtractURLScheme(inURI, nullptr, nullptr, &scheme);
}

NS_IMETHODIMP 
nsIOService::GetProtocolFlags(const char* scheme, uint32_t *flags)
{
    nsCOMPtr<nsIProtocolHandler> handler;
    nsresult rv = GetProtocolHandler(scheme, getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    rv = handler->GetProtocolFlags(flags);
    return rv;
}

class AutoIncrement
{
    public:
        explicit AutoIncrement(uint32_t *var) : mVar(var)
        {
            ++*var;
        }
        ~AutoIncrement()
        {
            --*mVar;
        }
    private:
        uint32_t *mVar;
};

nsresult
nsIOService::NewURI(const nsACString &aSpec, const char *aCharset, nsIURI *aBaseURI, nsIURI **result)
{
    NS_ASSERTION(NS_IsMainThread(), "wrong thread");

    static uint32_t recursionCount = 0;
    if (recursionCount >= MAX_RECURSION_COUNT)
        return NS_ERROR_MALFORMED_URI;
    AutoIncrement inc(&recursionCount);

    nsAutoCString scheme;
    nsresult rv = ExtractScheme(aSpec, scheme);
    if (NS_FAILED(rv)) {
        // then aSpec is relative
        if (!aBaseURI)
            return NS_ERROR_MALFORMED_URI;

        rv = aBaseURI->GetScheme(scheme);
        if (NS_FAILED(rv)) return rv;
    }

    // now get the handler for this scheme
    nsCOMPtr<nsIProtocolHandler> handler;
    rv = GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    return handler->NewURI(aSpec, aCharset, aBaseURI, result);
}


NS_IMETHODIMP 
nsIOService::NewFileURI(nsIFile *file, nsIURI **result)
{
    nsresult rv;
    NS_ENSURE_ARG_POINTER(file);

    nsCOMPtr<nsIProtocolHandler> handler;

    rv = GetProtocolHandler("file", getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    nsCOMPtr<nsIFileProtocolHandler> fileHandler( do_QueryInterface(handler, &rv) );
    if (NS_FAILED(rv)) return rv;
    
    return fileHandler->NewFileURI(file, result);
}

NS_IMETHODIMP
nsIOService::NewChannelFromURI(nsIURI *aURI, nsIChannel **result)
{
    return NewChannelFromURIWithProxyFlags(aURI, nullptr, 0, result);
}

NS_IMETHODIMP
nsIOService::NewChannelFromURIWithProxyFlags(nsIURI *aURI,
                                             nsIURI *aProxyURI,
                                             uint32_t aProxyFlags,
                                             nsIChannel **result)
{
    nsresult rv;
    NS_ENSURE_ARG_POINTER(aURI);

    nsAutoCString scheme;
    rv = aURI->GetScheme(scheme);
    if (NS_FAILED(rv))
        return rv;

    nsCOMPtr<nsIProtocolHandler> handler;
    rv = GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
    if (NS_FAILED(rv))
        return rv;

    uint32_t protoFlags;
    rv = handler->GetProtocolFlags(&protoFlags);
    if (NS_FAILED(rv))
        return rv;

    nsCOMPtr<nsIProxiedProtocolHandler> pph = do_QueryInterface(handler);
    if (pph)
        rv = pph->NewProxiedChannel(aURI, nullptr, aProxyFlags, aProxyURI, result);
    else
        rv = handler->NewChannel(aURI, result);
    if (NS_FAILED(rv))
        return rv;

    // Some extensions override the http protocol handler and provide their own
    // implementation. The channels returned from that implementation doesn't
    // seem to always implement the nsIUploadChannel2 interface, presumably
    // because it's a new interface.
    // Eventually we should remove this and simply require that http channels
    // implement the new interface.
    // See bug 529041
    if (!gHasWarnedUploadChannel2 && scheme.EqualsLiteral("http")) {
        nsCOMPtr<nsIUploadChannel2> uploadChannel2 = do_QueryInterface(*result);
        if (!uploadChannel2) {
            nsCOMPtr<nsIConsoleService> consoleService =
                do_GetService(NS_CONSOLESERVICE_CONTRACTID);
            if (consoleService) {
                consoleService->LogStringMessage(NS_LITERAL_STRING(
                    "Http channel implementation doesn't support nsIUploadChannel2. An extension has supplied a non-functional http protocol handler. This will break behavior and in future releases not work at all."
                                                                   ).get());
            }
            gHasWarnedUploadChannel2 = true;
        }
    }

    return NS_OK;
}

NS_IMETHODIMP
nsIOService::NewChannel(const nsACString &aSpec, const char *aCharset, nsIURI *aBaseURI, nsIChannel **result)
{
    nsresult rv;
    nsCOMPtr<nsIURI> uri;
    rv = NewURI(aSpec, aCharset, aBaseURI, getter_AddRefs(uri));
    if (NS_FAILED(rv)) return rv;

    return NewChannelFromURI(uri, result);
}

bool
nsIOService::IsLinkUp()
{
    InitializeNetworkLinkService();

    if (!mNetworkLinkService) {
        // We cannot decide, assume the link is up
        return true;
    }

    bool isLinkUp;
    nsresult rv;
    rv = mNetworkLinkService->GetIsLinkUp(&isLinkUp);
    if (NS_FAILED(rv)) {
        return true;
    }

    return isLinkUp;
}

NS_IMETHODIMP
nsIOService::GetOffline(bool *offline)
{
    *offline = mOffline;
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::SetOffline(bool offline)
{
    // When someone wants to go online (!offline) after we got XPCOM shutdown
    // throw ERROR_NOT_AVAILABLE to prevent return to online state.
    if ((mShutdown || mOfflineForProfileChange) && !offline)
        return NS_ERROR_NOT_AVAILABLE;

    // SetOffline() may re-enter while it's shutting down services.
    // If that happens, save the most recent value and it will be
    // processed when the first SetOffline() call is done bringing
    // down the service.
    mSetOfflineValue = offline;
    if (mSettingOffline) {
        return NS_OK;
    }

    mSettingOffline = true;

    nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();

    NS_ASSERTION(observerService, "The observer service should not be null");

    if (XRE_GetProcessType() == GeckoProcessType_Default) {
        if (observerService) {
            (void)observerService->NotifyObservers(nullptr,
                NS_IPC_IOSERVICE_SET_OFFLINE_TOPIC, offline ? 
                MOZ_UTF16("true") :
                MOZ_UTF16("false"));
        }
    }

    nsIIOService *subject = static_cast<nsIIOService *>(this);
    while (mSetOfflineValue != mOffline) {
        offline = mSetOfflineValue;

        if (offline && !mOffline) {
            NS_NAMED_LITERAL_STRING(offlineString, NS_IOSERVICE_OFFLINE);
            mOffline = true; // indicate we're trying to shutdown

            // don't care if notifications fail
            if (observerService)
                observerService->NotifyObservers(subject,
                                                 NS_IOSERVICE_GOING_OFFLINE_TOPIC,
                                                 offlineString.get());

            if (mDNSService)
                mDNSService->SetOffline(true);

            if (mSocketTransportService)
                mSocketTransportService->SetOffline(true);

            if (observerService)
                observerService->NotifyObservers(subject,
                                                 NS_IOSERVICE_OFFLINE_STATUS_TOPIC,
                                                 offlineString.get());
        }
        else if (!offline && mOffline) {
            // go online
            if (mDNSService) {
                mDNSService->SetOffline(false);
                DebugOnly<nsresult> rv = mDNSService->Init();
                NS_ASSERTION(NS_SUCCEEDED(rv), "DNS service init failed");
            }
            InitializeSocketTransportService();
            mOffline = false;    // indicate success only AFTER we've
                                    // brought up the services

            // trigger a PAC reload when we come back online
            if (mProxyService)
                mProxyService->ReloadPAC();

            // don't care if notification fails
            if (observerService)
                observerService->NotifyObservers(subject,
                                                 NS_IOSERVICE_OFFLINE_STATUS_TOPIC,
                                                 NS_LITERAL_STRING(NS_IOSERVICE_ONLINE).get());
        }
    }

    // Don't notify here, as the above notifications (if used) suffice.
    if ((mShutdown || mOfflineForProfileChange) && mOffline) {
        // be sure to try and shutdown both (even if the first fails)...
        // shutdown dns service first, because it has callbacks for socket transport
        if (mDNSService) {
            DebugOnly<nsresult> rv = mDNSService->Shutdown();
            NS_ASSERTION(NS_SUCCEEDED(rv), "DNS service shutdown failed");
        }
        if (mSocketTransportService) {
            DebugOnly<nsresult> rv = mSocketTransportService->Shutdown();
            NS_ASSERTION(NS_SUCCEEDED(rv), "socket transport service shutdown failed");
        }
    }

    mSettingOffline = false;

    return NS_OK;
}


NS_IMETHODIMP
nsIOService::AllowPort(int32_t inPort, const char *scheme, bool *_retval)
{
    int16_t port = inPort;
    if (port == -1) {
        *_retval = true;
        return NS_OK;
    }

    if (port == 0) {
        *_retval = false;
        return NS_OK;
    }
        
    // first check to see if the port is in our blacklist:
    int32_t badPortListCnt = mRestrictedPortList.Length();
    for (int i=0; i<badPortListCnt; i++)
    {
        if (port == mRestrictedPortList[i])
        {
            *_retval = false;

            // check to see if the protocol wants to override
            if (!scheme)
                return NS_OK;
            
            nsCOMPtr<nsIProtocolHandler> handler;
            nsresult rv = GetProtocolHandler(scheme, getter_AddRefs(handler));
            if (NS_FAILED(rv)) return rv;

            // let the protocol handler decide
            return handler->AllowPort(port, scheme, _retval);
        }
    }

    *_retval = true;
    return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////

void
nsIOService::PrefsChanged(nsIPrefBranch *prefs, const char *pref)
{
    if (!prefs) return;

    // Look for extra ports to block
    if (!pref || strcmp(pref, PORT_PREF("banned")) == 0)
        ParsePortList(prefs, PORT_PREF("banned"), false);

    // ...as well as previous blocks to remove.
    if (!pref || strcmp(pref, PORT_PREF("banned.override")) == 0)
        ParsePortList(prefs, PORT_PREF("banned.override"), true);

    if (!pref || strcmp(pref, AUTODIAL_PREF) == 0) {
        bool enableAutodial = false;
        nsresult rv = prefs->GetBoolPref(AUTODIAL_PREF, &enableAutodial);
        // If pref not found, default to disabled.
        mAutoDialEnabled = enableAutodial;
        if (NS_SUCCEEDED(rv)) {
            if (mSocketTransportService)
                mSocketTransportService->SetAutodialEnabled(enableAutodial);
        }
    }

    if (!pref || strcmp(pref, MANAGE_OFFLINE_STATUS_PREF) == 0) {
        bool manage;
        if (mNetworkLinkServiceInitialized &&
            NS_SUCCEEDED(prefs->GetBoolPref(MANAGE_OFFLINE_STATUS_PREF,
                                            &manage)))
            SetManageOfflineStatus(manage);
    }

    if (!pref || strcmp(pref, NECKO_BUFFER_CACHE_COUNT_PREF) == 0) {
        int32_t count;
        if (NS_SUCCEEDED(prefs->GetIntPref(NECKO_BUFFER_CACHE_COUNT_PREF,
                                           &count)))
            /* check for bogus values and default if we find such a value */
            if (count > 0)
                gDefaultSegmentCount = count;
    }
    
    if (!pref || strcmp(pref, NECKO_BUFFER_CACHE_SIZE_PREF) == 0) {
        int32_t size;
        if (NS_SUCCEEDED(prefs->GetIntPref(NECKO_BUFFER_CACHE_SIZE_PREF,
                                           &size)))
            /* check for bogus values and default if we find such a value
             * the upper limit here is arbitrary. having a 1mb segment size
             * is pretty crazy.  if you remove this, consider adding some
             * integer rollover test.
             */
            if (size > 0 && size < 1024*1024)
                gDefaultSegmentSize = size;
        NS_WARN_IF_FALSE( (!(size & (size - 1))) , "network segment size is not a power of 2!");
    }

    if (!pref || strcmp(pref, NETWORK_NOTIFY_CHANGED_PREF) == 0) {
        bool allow;
        nsresult rv = prefs->GetBoolPref(NETWORK_NOTIFY_CHANGED_PREF, &allow);
        if (NS_SUCCEEDED(rv)) {
            mNetworkNotifyChanged = allow;
        }
    }
}

void
nsIOService::ParsePortList(nsIPrefBranch *prefBranch, const char *pref, bool remove)
{
    nsXPIDLCString portList;

    // Get a pref string and chop it up into a list of ports.
    prefBranch->GetCharPref(pref, getter_Copies(portList));
    if (portList) {
        nsTArray<nsCString> portListArray;
        ParseString(portList, ',', portListArray);
        uint32_t index;
        for (index=0; index < portListArray.Length(); index++) {
            portListArray[index].StripWhitespace();
            int32_t portBegin, portEnd;

            if (PR_sscanf(portListArray[index].get(), "%d-%d", &portBegin, &portEnd) == 2) {
               if ((portBegin < 65536) && (portEnd < 65536)) {
                   int32_t curPort;
                   if (remove) {
                        for (curPort=portBegin; curPort <= portEnd; curPort++)
                            mRestrictedPortList.RemoveElement(curPort);
                   } else {
                        for (curPort=portBegin; curPort <= portEnd; curPort++)
                            mRestrictedPortList.AppendElement(curPort);
                   }
               }
            } else {
               nsresult aErrorCode;
               int32_t port = portListArray[index].ToInteger(&aErrorCode);
               if (NS_SUCCEEDED(aErrorCode) && port < 65536) {
                   if (remove)
                       mRestrictedPortList.RemoveElement(port);
                   else
                       mRestrictedPortList.AppendElement(port);
               }
            }

        }
    }
}

void
nsIOService::GetPrefBranch(nsIPrefBranch **result)
{
    *result = nullptr;
    CallGetService(NS_PREFSERVICE_CONTRACTID, result);
}

// nsIObserver interface
NS_IMETHODIMP
nsIOService::Observe(nsISupports *subject,
                     const char *topic,
                     const char16_t *data)
{
    if (!strcmp(topic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {
        nsCOMPtr<nsIPrefBranch> prefBranch = do_QueryInterface(subject);
        if (prefBranch)
            PrefsChanged(prefBranch, NS_ConvertUTF16toUTF8(data).get());
    } else if (!strcmp(topic, kProfileChangeNetTeardownTopic)) {
        if (!mOffline) {
            mOfflineForProfileChange = true;
            SetOffline(true);
        }
    } else if (!strcmp(topic, kProfileChangeNetRestoreTopic)) {
        if (mOfflineForProfileChange) {
            mOfflineForProfileChange = false;
            if (!mManageOfflineStatus ||
                NS_FAILED(OnNetworkLinkEvent(NS_NETWORK_LINK_DATA_UNKNOWN))) {
                SetOffline(false);
            }
        } 
    } else if (!strcmp(topic, kProfileDoChange)) { 
        if (data && NS_LITERAL_STRING("startup").Equals(data)) {
            // Lazy initialization of network link service (see bug 620472)
            InitializeNetworkLinkService();
            // Set up the initilization flag regardless the actuall result.
            // If we fail here, we will fail always on.
            mNetworkLinkServiceInitialized = true;
            // And now reflect the preference setting
            nsCOMPtr<nsIPrefBranch> prefBranch;
            GetPrefBranch(getter_AddRefs(prefBranch));
            PrefsChanged(prefBranch, MANAGE_OFFLINE_STATUS_PREF);
        }
    } else if (!strcmp(topic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
        // Remember we passed XPCOM shutdown notification to prevent any
        // changes of the offline status from now. We must not allow going
        // online after this point.
        mShutdown = true;

        SetOffline(true);

        // Break circular reference.
        mProxyService = nullptr;
    } else if (!strcmp(topic, NS_NETWORK_LINK_TOPIC)) {
        if (!mOfflineForProfileChange && mManageOfflineStatus) {
            OnNetworkLinkEvent(NS_ConvertUTF16toUTF8(data).get());
        }
    } else if (!strcmp(topic, NS_WIDGET_WAKE_OBSERVER_TOPIC)) {
        // coming back alive from sleep
        nsCOMPtr<nsIObserverService> observerService =
            mozilla::services::GetObserverService();

        NS_ASSERTION(observerService, "The observer service should not be null");

        if (observerService && mNetworkNotifyChanged) {
            (void)observerService->
                NotifyObservers(nullptr,
                                NS_NETWORK_LINK_TOPIC,
                                MOZ_UTF16(NS_NETWORK_LINK_DATA_CHANGED));
        }
    }

    return NS_OK;
}

// nsINetUtil interface
NS_IMETHODIMP
nsIOService::ParseContentType(const nsACString &aTypeHeader,
                              nsACString &aCharset,
                              bool *aHadCharset,
                              nsACString &aContentType)
{
    net_ParseContentType(aTypeHeader, aContentType, aCharset, aHadCharset);
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::ProtocolHasFlags(nsIURI   *uri,
                              uint32_t  flags,
                              bool     *result)
{
    NS_ENSURE_ARG(uri);

    *result = false;
    nsAutoCString scheme;
    nsresult rv = uri->GetScheme(scheme);
    NS_ENSURE_SUCCESS(rv, rv);
  
    uint32_t protocolFlags;
    rv = GetProtocolFlags(scheme.get(), &protocolFlags);

    if (NS_SUCCEEDED(rv)) {
        *result = (protocolFlags & flags) == flags;
    }
  
    return rv;
}

NS_IMETHODIMP
nsIOService::URIChainHasFlags(nsIURI   *uri,
                              uint32_t  flags,
                              bool     *result)
{
    nsresult rv = ProtocolHasFlags(uri, flags, result);
    NS_ENSURE_SUCCESS(rv, rv);

    if (*result) {
        return rv;
    }

    // Dig deeper into the chain.  Note that this is not a do/while loop to
    // avoid the extra addref/release on |uri| in the common (non-nested) case.
    nsCOMPtr<nsINestedURI> nestedURI = do_QueryInterface(uri);
    while (nestedURI) {
        nsCOMPtr<nsIURI> innerURI;
        rv = nestedURI->GetInnerURI(getter_AddRefs(innerURI));
        NS_ENSURE_SUCCESS(rv, rv);

        rv = ProtocolHasFlags(innerURI, flags, result);

        if (*result) {
            return rv;
        }

        nestedURI = do_QueryInterface(innerURI);
    }

    return rv;
}

NS_IMETHODIMP
nsIOService::ToImmutableURI(nsIURI* uri, nsIURI** result)
{
    if (!uri) {
        *result = nullptr;
        return NS_OK;
    }

    nsresult rv = NS_EnsureSafeToReturn(uri, result);
    NS_ENSURE_SUCCESS(rv, rv);

    NS_TryToSetImmutable(*result);
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::NewSimpleNestedURI(nsIURI* aURI, nsIURI** aResult)
{
    NS_ENSURE_ARG(aURI);

    nsCOMPtr<nsIURI> safeURI;
    nsresult rv = NS_EnsureSafeToReturn(aURI, getter_AddRefs(safeURI));
    NS_ENSURE_SUCCESS(rv, rv);

    NS_IF_ADDREF(*aResult = new nsSimpleNestedURI(safeURI));
    return *aResult ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}

NS_IMETHODIMP
nsIOService::SetManageOfflineStatus(bool aManage)
{
    nsresult rv = NS_OK;

    // SetManageOfflineStatus must throw when we fail to go from non-managed
    // to managed.  Usually because there is no link monitoring service
    // available.  Failure to do this switch is detected by a failure of
    // OnNetworkLinkEvent().  When there is no network link available during
    // call to InitializeNetworkLinkService(), application is put to offline
    // mode.  And when we change mMangeOfflineStatus to false on the next line
    // we get stuck on being offline even though the link becomes later
    // available.
    bool wasManaged = mManageOfflineStatus;
    mManageOfflineStatus = aManage;

    InitializeNetworkLinkService();

    if (mManageOfflineStatus && !wasManaged) {
        rv = OnNetworkLinkEvent(NS_NETWORK_LINK_DATA_UNKNOWN);
        if (NS_FAILED(rv))
            mManageOfflineStatus = false;
    }
    return rv;
}

NS_IMETHODIMP
nsIOService::GetManageOfflineStatus(bool* aManage) {
    *aManage = mManageOfflineStatus;
    return NS_OK;
}

// input argument 'data' is already UTF8'ed
nsresult
nsIOService::OnNetworkLinkEvent(const char *data)
{
    if (!mNetworkLinkService)
        return NS_ERROR_FAILURE;

    if (mShutdown)
        return NS_ERROR_NOT_AVAILABLE;

    if (mManageOfflineStatus)
        return NS_OK;

    if (!strcmp(data, NS_NETWORK_LINK_DATA_DOWN)) {
        // check to make sure this won't collide with Autodial
        if (mSocketTransportService) {
            bool autodialEnabled = false;
            mSocketTransportService->GetAutodialEnabled(&autodialEnabled);
            // If autodialing-on-link-down is enabled, check if the OS auto
            // dial option is set to always autodial. If so, then we are
            // always up for the purposes of offline management.
            if (autodialEnabled) {
#if defined(XP_WIN)
                // On Windows, we should first check with the OS to see if
                // autodial is enabled.  If it is enabled then we are allowed
                // to manage the offline state.
                if (nsNativeConnectionHelper::IsAutodialEnabled()) {
                    return SetOffline(false);
                }
#else
                return SetOffline(false);
#endif
            }
        }
    }

    bool isUp;
    if (!strcmp(data, NS_NETWORK_LINK_DATA_DOWN)) {
        isUp = false;
    } else if (!strcmp(data, NS_NETWORK_LINK_DATA_UP)) {
        isUp = true;
    } else if (!strcmp(data, NS_NETWORK_LINK_DATA_CHANGED)) {
        // CHANGED events are handled by others
        return NS_OK;
    } else if (!strcmp(data, NS_NETWORK_LINK_DATA_UNKNOWN)) {
        nsresult rv = mNetworkLinkService->GetIsLinkUp(&isUp);
        NS_ENSURE_SUCCESS(rv, rv);
    } else {
        NS_WARNING("Unhandled network event!");
        return NS_OK;
    }
    return SetOffline(!isUp);
}

NS_IMETHODIMP
nsIOService::EscapeString(const nsACString& aString,
                          uint32_t aEscapeType,
                          nsACString& aResult)
{
  NS_ENSURE_ARG_MAX(aEscapeType, 4);

  nsAutoCString stringCopy(aString);
  nsCString result;

  if (!NS_Escape(stringCopy, result, (nsEscapeMask) aEscapeType))
    return NS_ERROR_OUT_OF_MEMORY;

  aResult.Assign(result);

  return NS_OK;
}

NS_IMETHODIMP 
nsIOService::EscapeURL(const nsACString &aStr, 
                       uint32_t aFlags, nsACString &aResult)
{
  aResult.Truncate();
  NS_EscapeURL(aStr.BeginReading(), aStr.Length(), 
               aFlags | esc_AlwaysCopy, aResult);
  return NS_OK;
}

NS_IMETHODIMP 
nsIOService::UnescapeString(const nsACString &aStr, 
                            uint32_t aFlags, nsACString &aResult)
{
  aResult.Truncate();
  NS_UnescapeURL(aStr.BeginReading(), aStr.Length(), 
                 aFlags | esc_AlwaysCopy, aResult);
  return NS_OK;
}

NS_IMETHODIMP
nsIOService::ExtractCharsetFromContentType(const nsACString &aTypeHeader,
                                           nsACString &aCharset,
                                           int32_t *aCharsetStart,
                                           int32_t *aCharsetEnd,
                                           bool *aHadCharset)
{
    nsAutoCString ignored;
    net_ParseContentType(aTypeHeader, ignored, aCharset, aHadCharset,
                         aCharsetStart, aCharsetEnd);
    if (*aHadCharset && *aCharsetStart == *aCharsetEnd) {
        *aHadCharset = false;
    }
    return NS_OK;
}

// nsISpeculativeConnect
class IOServiceProxyCallback MOZ_FINAL : public nsIProtocolProxyCallback
{
    ~IOServiceProxyCallback() {}

public:
    NS_DECL_ISUPPORTS
    NS_DECL_NSIPROTOCOLPROXYCALLBACK

    IOServiceProxyCallback(nsIInterfaceRequestor *aCallbacks,
                           nsIOService *aIOService)
        : mCallbacks(aCallbacks)
        , mIOService(aIOService)
    { }

private:
    nsRefPtr<nsIInterfaceRequestor> mCallbacks;
    nsRefPtr<nsIOService>           mIOService;
};

NS_IMPL_ISUPPORTS(IOServiceProxyCallback, nsIProtocolProxyCallback)

NS_IMETHODIMP
IOServiceProxyCallback::OnProxyAvailable(nsICancelable *request, nsIURI *aURI,
                                         nsIProxyInfo *pi, nsresult status)
{
    // Checking proxy status for speculative connect
    nsAutoCString type;
    if (NS_SUCCEEDED(status) && pi &&
        NS_SUCCEEDED(pi->GetType(type)) &&
        !type.EqualsLiteral("direct")) {
        // proxies dont do speculative connect
        return NS_OK;
    }

    nsAutoCString scheme;
    nsresult rv = aURI->GetScheme(scheme);
    if (NS_FAILED(rv))
        return NS_OK;

    nsCOMPtr<nsIProtocolHandler> handler;
    rv = mIOService->GetProtocolHandler(scheme.get(),
                                        getter_AddRefs(handler));
    if (NS_FAILED(rv))
        return NS_OK;

    nsCOMPtr<nsISpeculativeConnect> speculativeHandler =
        do_QueryInterface(handler);
    if (!speculativeHandler)
        return NS_OK;

    speculativeHandler->SpeculativeConnect(aURI,
                                           mCallbacks);
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::SpeculativeConnect(nsIURI *aURI,
                                nsIInterfaceRequestor *aCallbacks)
{
    // Check for proxy information. If there is a proxy configured then a
    // speculative connect should not be performed because the potential
    // reward is slim with tcp peers closely located to the browser.
    nsresult rv;
    nsCOMPtr<nsIProtocolProxyService> pps =
            do_GetService(NS_PROTOCOLPROXYSERVICE_CONTRACTID, &rv);
    if (NS_FAILED(rv))
        return rv;

    nsCOMPtr<nsICancelable> cancelable;
    nsRefPtr<IOServiceProxyCallback> callback =
        new IOServiceProxyCallback(aCallbacks, this);
    return pps->AsyncResolve(aURI, 0, callback, getter_AddRefs(cancelable));
}