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Implement IP match function

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This commit is contained in:
Albert Vaca Cintora 2023-07-31 11:04:16 +02:00
parent b3ac0df630
commit bbfbd53123
1 changed files with 51 additions and 4 deletions
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55
core/backends/lan/mdns_wrapper.cpp
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@ -243,13 +243,60 @@ static mdns_string_t createMdnsString(const QByteArray &str)
return mdns_string_t{str.constData(), (size_t)str.length()};
}
static QHostAddress findBestAddressMatch(QVector<QHostAddress> hostAddresses, const struct sockaddr *fromAddress)
int countCommonLeadingBits(quint32 int1, quint32 int2) {
int count = 0;
while (int1 != 0 && int2 != 0) {
if ((int1 & 0x80000000) == (int2 & 0x80000000)) {
count++;
int1 <<= 1;
int2 <<= 1;
} else {
break;
}
}
return count;
}
static QHostAddress findBestAddressMatchV4(QVector<QHostAddress> hostAddresses, const struct sockaddr *fromAddress)
{
Q_ASSERT(!hostAddresses.empty());
if (hostAddresses.size() == 1 || fromAddress == nullptr) {
return hostAddresses[0];
}
// FIXME
QHostAddress otherIp = QHostAddress(fromAddress);
if (otherIp.protocol() != QAbstractSocket::IPv4Protocol) {
return hostAddresses[0];
}
// qDebug() << "I have more than one IP address:" << hostAddresses << "- Finding best match for source IP:" << otherIp;
QHostAddress matchingIp = hostAddresses[0];
int matchingBits = -1;
quint32 rawOtherIp = otherIp.toIPv4Address();
for (const QHostAddress& ip : hostAddresses) {
Q_ASSERT(ip.protocol() == QAbstractSocket::IPv4Protocol);
quint32 rawMyIp = ip.toIPv4Address();
// Since we don't have the network mask, we just compare the prefixes of the IPs to find the longest match
int matchingBitsCount = countCommonLeadingBits(rawMyIp, rawOtherIp);
if (matchingBitsCount > matchingBits) {
matchingIp = ip;
matchingBits = matchingBitsCount;
}
}
// qDebug() << "Found match:" << matchingIp;
return matchingIp;
}
static QHostAddress findBestAddressMatchV6(QVector<QHostAddress> hostAddresses, const struct sockaddr *fromAddress)
{
Q_ASSERT(!hostAddresses.empty());
// We could do the same logic for v6 that we do for V4, but we don't care that much about IPv6
return hostAddresses[0];
Q_UNUSED(fromAddress);
}
static mdns_record_t createMdnsRecord(const Announcer::AnnouncedInfo &self,
@ -275,11 +322,11 @@ static mdns_record_t createMdnsRecord(const Announcer::AnnouncedInfo &self,
break;
case MDNS_RECORDTYPE_A: // maps "<hostname>.local." to IPv4
answer.name = createMdnsString(self.hostname);
answer.data.a.addr = qHostAddresstoSockaddr(findBestAddressMatch(self.addressesV4, fromAddress));
answer.data.a.addr = qHostAddressToSockaddr(findBestAddressMatchV4(self.addressesV4, fromAddress));
break;
case MDNS_RECORDTYPE_AAAA: // maps "<hostname>.local." to IPv6
answer.name = createMdnsString(self.hostname);
answer.data.aaaa.addr = qHostAddresstoSockaddr6(findBestAddressMatch(self.addressesV6, fromAddress));
answer.data.aaaa.addr = qHostAddressToSockaddr6(findBestAddressMatchV6(self.addressesV6, fromAddress));
break;
case MDNS_RECORDTYPE_TXT:
answer.name = createMdnsString(self.serviceInstance);