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Commit b1aa65a7 authored by chenbruce's avatar chenbruce
Browse files

Add setupUdpSocket() and use it in send_dg() 

When implementing mDNS .local resolution, it would have the exact
same code to setup a udp socket as send_dg(). Factor it into a
common helper function.

Bug: 140857615
Test: cd packages/modules/DnsResolver && atest
Change-Id: Id2a5945b85ea306ddbcc6ee84aa876ac0b7709fc
parent 76620646

res_send.cpp

+42 −31
Original line number Diff line number Diff line
@@ -146,6 +146,7 @@ using android::netdutils::Stopwatch; 
static int send_vc(res_state statp, res_params* params, const uint8_t* buf, int buflen,

                   uint8_t* ans, int anssiz, int* terrno, size_t ns, time_t* at, int* rcode,

                   int* delay);

static int setupUdpSocket(ResState* statp, const sockaddr* sockap, size_t addrIndex, int* terrno);

static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int buflen,

                   uint8_t* ans, int anssiz, int* terrno, size_t* ns, int* v_circuit,

                   int* gotsomewhere, time_t* at, int* rcode, int* delay);
@@ -997,58 +998,68 @@ bool ignoreInvalidAnswer(res_state statp, const sockaddr_storage& from, const ui 
    return false;

}



static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int buflen,

                   uint8_t* ans, int anssiz, int* terrno, size_t* ns, int* v_circuit,

                   int* gotsomewhere, time_t* at, int* rcode, int* delay) {

    // It should never happen, but just in case.

    if (*ns >= statp->nsaddrs.size()) {

        LOG(ERROR) << __func__ << ": Out-of-bound indexing: " << ns;

        *terrno = EINVAL;

        return -1;

    }



    *at = time(nullptr);

    *delay = 0;

    const sockaddr_storage ss = statp->nsaddrs[*ns];

    const sockaddr* nsap = reinterpret_cast<const sockaddr*>(&ss);

    const int nsaplen = sockaddrSize(nsap);

// return 1 when setup udp socket success.

// return 0 when timeout , bind error, network error(ex: Protocol not supported ...).

// return -1 when create socket fail, set socket option fail.

static int setupUdpSocket(ResState* statp, const sockaddr* sockap, size_t addrIndex, int* terrno) {

    statp->udpsocks[addrIndex].reset(socket(sockap->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0));



    if (statp->udpsocks[*ns] == -1) {

        statp->udpsocks[*ns].reset(socket(nsap->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0));

        if (statp->udpsocks[*ns] < 0) {

    if (statp->udpsocks[addrIndex] < 0) {

        *terrno = errno;

            PLOG(DEBUG) << __func__ << ": socket(dg): ";

        PLOG(ERROR) << __func__ << ": socket: ";

        switch (errno) {

            case EPROTONOSUPPORT:

            case EPFNOSUPPORT:

            case EAFNOSUPPORT:

                    return (0);

                return 0;

            default:

                    return (-1);

                return -1;

        }

    }



    const uid_t uid = statp->enforce_dns_uid ? AID_DNS : statp->uid;

        resolv_tag_socket(statp->udpsocks[*ns], uid, statp->pid);

    resolv_tag_socket(statp->udpsocks[addrIndex], uid, statp->pid);

    if (statp->_mark != MARK_UNSET) {

            if (setsockopt(statp->udpsocks[*ns], SOL_SOCKET, SO_MARK, &(statp->_mark),

        if (setsockopt(statp->udpsocks[addrIndex], SOL_SOCKET, SO_MARK, &(statp->_mark),

                       sizeof(statp->_mark)) < 0) {

            *terrno = errno;

            statp->closeSockets();

            return -1;

        }

    }



    if (random_bind(statp->udpsocks[addrIndex], sockap->sa_family) < 0) {

        *terrno = errno;

        dump_error("bind", sockap);

        statp->closeSockets();

        return 0;

    }

    return 1;

}



static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int buflen,

                   uint8_t* ans, int anssiz, int* terrno, size_t* ns, int* v_circuit,

                   int* gotsomewhere, time_t* at, int* rcode, int* delay) {

    // It should never happen, but just in case.

    if (*ns >= statp->nsaddrs.size()) {

        LOG(ERROR) << __func__ << ": Out-of-bound indexing: " << ns;

        *terrno = EINVAL;

        return -1;

    }



    *at = time(nullptr);

    *delay = 0;

    const sockaddr_storage ss = statp->nsaddrs[*ns];

    const sockaddr* nsap = reinterpret_cast<const sockaddr*>(&ss);



    if (statp->udpsocks[*ns] == -1) {

        int result = setupUdpSocket(statp, nsap, *ns, terrno);

        if (result <= 0) return result;



        // Use a "connected" datagram socket to receive an ECONNREFUSED error

        // on the next socket operation when the server responds with an

        // ICMP port-unreachable error. This way we can detect the absence of

        // a nameserver without timing out.

        if (random_bind(statp->udpsocks[*ns], nsap->sa_family) < 0) {

            *terrno = errno;

            dump_error("bind(dg)", nsap);

            statp->closeSockets();

            return (0);

        }

        if (connect(statp->udpsocks[*ns], nsap, (socklen_t)nsaplen) < 0) {

        if (connect(statp->udpsocks[*ns], nsap, sockaddrSize(nsap)) < 0) {

            *terrno = errno;

            dump_error("connect(dg)", nsap);

            statp->closeSockets();