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Commit c3f77721 authored by Ken Chen's avatar Ken Chen
Browse files

Move doDns64Synthesis and doDns64ReverseLookup around 

It needs to do a DNS64 synthesis or DNS64 reverse lookup only if the
requester can do a DNS query or a reversed lookup. Move DNS64 handlings
right after DNS (and reversed) lookups.

Bug: 288340533
Test: atest
Change-Id: I488bfb5e6dabe254769a1c199459c5960653038f
parent 37ade6cc

DnsProxyListener.cpp

+29 −49
Original line number Diff line number Diff line
@@ -818,23 +818,16 @@ void DnsProxyListener::GetAddrInfoHandler::doDns64Synthesis(int32_t* rv, addrinf 


    if (ipv6WantedButNoData) {

        // If caller wants IPv6 answers but no data, try to query IPv4 answers for synthesis

        const uid_t uid = mClient->getUid();

        if (startQueryLimiter(uid)) {

        const char* host = mHost.starts_with('^') ? nullptr : mHost.c_str();

        const char* service = mService.starts_with('^') ? nullptr : mService.c_str();

        mHints->ai_family = AF_INET;

        // Don't need to do freeaddrinfo(res) before starting new DNS lookup because previous

        // DNS lookup is failed with error EAI_NODATA.

        *rv = resolv_getaddrinfo(host, service, mHints.get(), &mNetContext, res, event);

            endQueryLimiter(uid);

        if (*rv) {

            *rv = EAI_NODATA;  // return original error code

            return;

        }

        } else {

            LOG(ERROR) << __func__ << ": from UID " << uid << ", max concurrent queries reached";

            return;

        }

    }



    if (!synthesizeNat64PrefixWithARecord(prefix, res, unspecWantedButNoIPv6, &mNetContext)) {
@@ -865,6 +858,7 @@ void DnsProxyListener::GetAddrInfoHandler::run() { 
        const char* service = mService.starts_with('^') ? nullptr : mService.c_str();

        if (evaluate_domain_name(mNetContext, host)) {

            rv = resolv_getaddrinfo(host, service, mHints.get(), &mNetContext, &result, &event);

            doDns64Synthesis(&rv, &result, &event);

        } else {

            rv = EAI_SYSTEM;

        }
@@ -877,7 +871,6 @@ void DnsProxyListener::GetAddrInfoHandler::run() { 
                   << ", max concurrent queries reached";

    }



    doDns64Synthesis(&rv, &result, &event);

    const int32_t latencyUs = saturate_cast<int32_t>(s.timeTakenUs());

    event.set_latency_micros(latencyUs);

    event.set_event_type(EVENT_GETADDRINFO);
@@ -1244,19 +1237,12 @@ void DnsProxyListener::GetHostByNameHandler::doDns64Synthesis(int32_t* rv, hoste 
    }



    // If caller wants IPv6 answers but no data, try to query IPv4 answers for synthesis

    const uid_t uid = mClient->getUid();

    if (startQueryLimiter(uid)) {

    const char* name = mName.starts_with('^') ? nullptr : mName.c_str();

    *rv = resolv_gethostbyname(name, AF_INET, hbuf, buf, buflen, &mNetContext, hpp, event);

        endQueryLimiter(uid);

    if (*rv) {

        *rv = EAI_NODATA;  // return original error code

        return;

    }

    } else {

        LOG(ERROR) << __func__ << ": from UID " << uid << ", max concurrent queries reached";

        return;

    }



    if (!synthesizeNat64PrefixWithARecord(prefix, *hpp)) {

        // If caller wants IPv6 answers but no data and failed to synthesize IPv4 answers,
@@ -1281,6 +1267,7 @@ void DnsProxyListener::GetHostByNameHandler::run() { 
        if (evaluate_domain_name(mNetContext, name)) {

            rv = resolv_gethostbyname(name, mAf, &hbuf, tmpbuf, sizeof tmpbuf, &mNetContext, &hp,

                                      &event);

            doDns64Synthesis(&rv, &hbuf, tmpbuf, sizeof tmpbuf, &hp, &event);

        } else {

            rv = EAI_SYSTEM;

        }
@@ -1291,7 +1278,6 @@ void DnsProxyListener::GetHostByNameHandler::run() { 
                   << ", max concurrent queries reached";

    }



    doDns64Synthesis(&rv, &hbuf, tmpbuf, sizeof tmpbuf, &hp, &event);

    const int32_t latencyUs = saturate_cast<int32_t>(s.timeTakenUs());

    event.set_latency_micros(latencyUs);

    event.set_event_type(EVENT_GETHOSTBYNAME);
@@ -1406,13 +1392,10 @@ void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(hostent* hbuf, 
        return;

    }



    const uid_t uid = mClient->getUid();

    if (startQueryLimiter(uid)) {

    // Remove NAT64 prefix and do reverse DNS query

    struct in_addr v4addr = {.s_addr = v6addr.s6_addr32[3]};

    resolv_gethostbyaddr(&v4addr, sizeof(v4addr), AF_INET, hbuf, buf, buflen, &mNetContext, hpp,

                         event);

        endQueryLimiter(uid);

    if (*hpp && (*hpp)->h_addr_list[0]) {

        // Replace IPv4 address with original queried IPv6 address in place. The space has

        // reserved by dns_gethtbyaddr() and netbsd_gethostent_r() in
@@ -1425,9 +1408,6 @@ void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(hostent* hbuf, 
    } else {

        LOG(ERROR) << __func__ << ": hpp or (*hpp)->h_addr_list[0] is null";

    }

    } else {

        LOG(ERROR) << __func__ << ": from UID " << uid << ", max concurrent queries reached";

    }

}



void DnsProxyListener::GetHostByAddrHandler::run() {
@@ -1453,6 +1433,7 @@ void DnsProxyListener::GetHostByAddrHandler::run() { 
        } else {

            rv = resolv_gethostbyaddr(&mAddress, mAddressLen, mAddressFamily, &hbuf, tmpbuf,

                                      sizeof tmpbuf, &mNetContext, &hp, &event);

            doDns64ReverseLookup(&hbuf, tmpbuf, sizeof tmpbuf, &hp, &event);

        }

        endQueryLimiter(uid);

    } else {
@@ -1461,7 +1442,6 @@ void DnsProxyListener::GetHostByAddrHandler::run() { 
                   << ", max concurrent queries reached";

    }



    doDns64ReverseLookup(&hbuf, tmpbuf, sizeof tmpbuf, &hp, &event);

    const int32_t latencyUs = saturate_cast<int32_t>(s.timeTakenUs());

    event.set_latency_micros(latencyUs);

    event.set_event_type(EVENT_GETHOSTBYADDR);