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QNetworkInterface/Windows: solve 11 year old puzzle about Win32 API

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When I introduced QNetworkInterface in Qt 4.2, I didn't understand the
relationship between the prefix list and the unicast address list in the
IP_ADAPTERS_ADDRESSES structure. Turns out, there isn't a (direct) one
and the actual solution didn't come along until Windows Vista, adding
the prefix length to each address.

Change-Id: I6a556cca551116d77c7edf43f9c651dacb75348f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
This commit is contained in:
Thiago Macieira 2017-08-08 15:44:28 -07:00
parent 59e0b6d40c
commit 758982bd74
1 changed files with 8 additions and 59 deletions
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67
src/network/kernel/qnetworkinterface_win.cpp
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@ -103,45 +103,6 @@ QString QNetworkInterfaceManager::interfaceNameFromIndex(uint index)
return QString::number(index);
}
static QHash<QHostAddress, QHostAddress> ipv4Netmasks()
{
//Retrieve all the IPV4 addresses & netmasks
IP_ADAPTER_INFO staticBuf[2]; // 2 is arbitrary
PIP_ADAPTER_INFO pAdapter = staticBuf;
ULONG bufSize = sizeof staticBuf;
QHash<QHostAddress, QHostAddress> ipv4netmasks;
DWORD retval = GetAdaptersInfo(pAdapter, &bufSize);
if (retval == ERROR_BUFFER_OVERFLOW) {
// need more memory
pAdapter = (IP_ADAPTER_INFO *)malloc(bufSize);
if (!pAdapter)
return ipv4netmasks;
// try again
if (GetAdaptersInfo(pAdapter, &bufSize) != ERROR_SUCCESS) {
free(pAdapter);
return ipv4netmasks;
}
} else if (retval != ERROR_SUCCESS) {
// error
return ipv4netmasks;
}
// iterate over the list and add the entries to our listing
for (PIP_ADAPTER_INFO ptr = pAdapter; ptr; ptr = ptr->Next) {
for (PIP_ADDR_STRING addr = &ptr->IpAddressList; addr; addr = addr->Next) {
QHostAddress address(QLatin1String(addr->IpAddress.String));
QHostAddress mask(QLatin1String(addr->IpMask.String));
ipv4netmasks[address] = mask;
}
}
if (pAdapter != staticBuf)
free(pAdapter);
return ipv4netmasks;
}
static QList<QNetworkInterfacePrivate *> interfaceListing()
{
QList<QNetworkInterfacePrivate *> interfaces;
@ -149,7 +110,6 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
PIP_ADAPTER_ADDRESSES pAdapter = staticBuf;
ULONG bufSize = sizeof staticBuf;
const QHash<QHostAddress, QHostAddress> &ipv4netmasks = ipv4Netmasks();
ULONG flags = GAA_FLAG_INCLUDE_PREFIX |
GAA_FLAG_SKIP_DNS_SERVER |
GAA_FLAG_SKIP_MULTICAST;
@ -176,7 +136,6 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
// field we access from IP_ADAPTER_ADDRESSES_LH)
Q_ASSERT(ptr->Length >= offsetof(IP_ADAPTER_ADDRESSES, Luid));
Q_ASSERT(ptr->Length >= offsetof(IP_ADAPTER_ADDRESSES, Ipv6IfIndex));
Q_ASSERT(ptr->Length >= offsetof(IP_ADAPTER_ADDRESSES, FirstPrefix));
QNetworkInterfacePrivate *iface = new QNetworkInterfacePrivate;
interfaces << iface;
@ -211,27 +170,17 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
// loopback if it has no address
iface->flags |= QNetworkInterface::IsLoopBack;
// The GetAdaptersAddresses call has an interesting semantic:
// It can return a number N of addresses and a number M of prefixes.
// But if you have IPv6 addresses, generally N > M.
// I cannot find a way to relate the Address to the Prefix, aside from stopping
// the iteration at the last Prefix entry and assume that it applies to all addresses
// from that point on.
PIP_ADAPTER_PREFIX pprefix = 0;
pprefix = ptr->FirstPrefix;
// parse the IP (unicast) addresses
for (PIP_ADAPTER_UNICAST_ADDRESS addr = ptr->FirstUnicastAddress; addr; addr = addr->Next) {
Q_ASSERT(addr->Length >= offsetof(IP_ADAPTER_UNICAST_ADDRESS, OnLinkPrefixLength));
// skip addresses in invalid state
if (addr->DadState == IpDadStateInvalid)
continue;
QNetworkAddressEntry entry;
entry.setIp(addressFromSockaddr(addr->Address.lpSockaddr));
if (pprefix) {
if (entry.ip().protocol() == QAbstractSocket::IPv4Protocol) {
entry.setNetmask(ipv4netmasks[entry.ip()]);
// broadcast address is set on postProcess()
} else { //IPV6
entry.setPrefixLength(pprefix->PrefixLength);
}
pprefix = pprefix->Next ? pprefix->Next : pprefix;
}
entry.setPrefixLength(addr->OnLinkPrefixLength);
iface->addressEntries << entry;
}
}