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Commit a3b0d378 authored by Automerger Merge Worker's avatar Automerger Merge Worker
Browse files

Support setting response probability by protocol am: 14e0a78a am: 20f8cfb7 am: 87c67cbf 

Change-Id: I5a871ea1bc00ce62dba03b48ad655abb16729274
parents d9920242 87c67cbf

tests/dns_responder/dns_responder.cpp

+32 −2
Original line number Diff line number Diff line
@@ -509,8 +509,38 @@ void DNSResponder::removeMappingBinaryPacket(const std::vector<uint8_t>& query) 
    }

}



// Set response probability on all supported protocols.

void DNSResponder::setResponseProbability(double response_probability) {

    response_probability_ = response_probability;

    setResponseProbability(response_probability, IPPROTO_TCP);

    setResponseProbability(response_probability, IPPROTO_UDP);

}



// Set response probability on specific protocol. It's caller's duty to ensure that the |protocol|

// can be supported by DNSResponder.

void DNSResponder::setResponseProbability(double response_probability, int protocol) {

    switch (protocol) {

        case IPPROTO_TCP:

            response_probability_tcp_ = response_probability;

            break;

        case IPPROTO_UDP:

            response_probability_udp_ = response_probability;

            break;

        default:

            LOG(FATAL) << "Unsupported protocol " << protocol;  // abort() by log level FATAL

    }

}



double DNSResponder::getResponseProbability(int protocol) const {

    switch (protocol) {

        case IPPROTO_TCP:

            return response_probability_tcp_;

        case IPPROTO_UDP:

            return response_probability_udp_;

        default:

            LOG(FATAL) << "Unsupported protocol " << protocol;  // abort() by log level FATAL

            // unreachable

            return -1;

    }

}



void DNSResponder::setEdns(Edns edns) {
@@ -709,7 +739,7 @@ bool DNSResponder::handleDNSRequest(const char* buffer, ssize_t len, int protoco 
    }

    // Ignore requests with the preset probability.

    auto constexpr bound = std::numeric_limits<unsigned>::max();

    if (arc4random_uniform(bound) > bound * response_probability_) {

    if (arc4random_uniform(bound) > bound * getResponseProbability(protocol)) {

        if (error_rcode_ < 0) {

            LOG(ERROR) << "Returning no response";

            return false;

tests/dns_responder/dns_responder.h

+10 −3
Original line number Diff line number Diff line
@@ -173,6 +173,7 @@ class DNSResponder { 
    void removeMappingBinaryPacket(const std::vector<uint8_t>& query);



    void setResponseProbability(double response_probability);

    void setResponseProbability(double response_probability, int protocol);

    void setEdns(Edns edns);

    bool running() const;

    bool startServer();
@@ -276,6 +277,8 @@ class DNSResponder { 
    // TODO: Move createListeningSocket to resolv_test_utils.h

    android::base::unique_fd createListeningSocket(int socket_type);



    double getResponseProbability(int protocol) const;



    // Address and service to listen on TCP and UDP.

    const std::string listen_address_;

    const std::string listen_service_;
@@ -283,9 +286,13 @@ class DNSResponder { 
    const ns_rcode error_rcode_;

    // Mapping type the DNS server used to build the response.

    const MappingType mapping_type_;

    // Probability that a valid response is being sent instead of being sent

    // instead of returning error_rcode_.

    std::atomic<double> response_probability_ = 1.0;

    // Probability that a valid response on TCP is being sent instead of

    // returning error_rcode_ or no response.

    std::atomic<double> response_probability_tcp_ = 1.0;

    // Probability that a valid response on UDP is being sent instead of

    // returning error_rcode_ or no response.

    std::atomic<double> response_probability_udp_ = 1.0;



    // Maximum number of fds for epoll.

    const int EPOLL_MAX_EVENTS = 2;