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Commit cf0cfcb3 authored by Nucca Chen's avatar Nucca Chen Committed by Gerrit Code Review
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Merge "DNS64: return both synthesized IPv6 address and queried IPv4 address"

parents 610d5126 5d4650ff

DnsProxyListener.cpp

+108 −19
Original line number Diff line number Diff line
@@ -469,7 +469,7 @@ void logDnsQueryResult(const addrinfo* res) { 
                              NI_NUMERICHOST);

        if (!ret) {

            LOG(DEBUG) << __func__ << ": [" << i << "] " << ai->ai_flags << " " << ai->ai_family

                       << " " << ai->ai_socktype << " " << ai->ai_protocol;

                       << " " << ai->ai_socktype << " " << ai->ai_protocol << " " << ip_addr;

        } else {

            LOG(DEBUG) << __func__ << ": [" << i << "] numeric hostname translation fail " << ret;

        }
@@ -523,30 +523,95 @@ bool synthesizeNat64PrefixWithARecord(const netdutils::IPPrefix& prefix, struct 
    return true;

}



bool synthesizeNat64PrefixWithARecord(const netdutils::IPPrefix& prefix, addrinfo* result) {

    if (result == nullptr) return false;

    if (!onlyNonSpecialUseIPv4Addresses(result)) return false;

bool synthesizeNat64PrefixWithARecord(const netdutils::IPPrefix& prefix, addrinfo** res,

                                      bool unspecWantedButNoIPv6) {

    if (*res == nullptr) return false;

    if (!onlyNonSpecialUseIPv4Addresses(*res)) return false;

    if (!isValidNat64Prefix(prefix)) return false;



    struct sockaddr_storage ss = netdutils::IPSockAddr(prefix.ip());

    struct sockaddr_in6* v6prefix = (struct sockaddr_in6*)&ss;

    for (addrinfo* ai = result; ai; ai = ai->ai_next) {

        struct sockaddr_in sinOriginal = *(struct sockaddr_in*)ai->ai_addr;

        struct sockaddr_in6* sin6 = (struct sockaddr_in6*)ai->ai_addr;

        memset(sin6, 0, sizeof(sockaddr_in6));

    const sockaddr_storage ss = netdutils::IPSockAddr(prefix.ip());

    const sockaddr_in6* v6prefix = (sockaddr_in6*)&ss;

    addrinfo* const head4 = *res;

    addrinfo* head6 = nullptr;

    addrinfo* cur6 = nullptr;



    // Build a synthesized AAAA addrinfo list from the queried A addrinfo list. Here is the diagram

    // for the relationship of pointers.

    //

    // head4: point to the first queried A addrinfo

    // |

    // v

    // +-------------+   +-------------+

    // | addrinfo4#1 |-->| addrinfo4#2 |--> .. queried A addrinfo(s) for DNS64 synthesis

    // +-------------+   +-------------+

    //                   ^

    //                   |

    //                   cur4: current worked-on queried A addrinfo

    //

    // head6: point to the first synthesized AAAA addrinfo

    // |

    // v

    // +-------------+   +-------------+

    // | addrinfo6#1 |-->| addrinfo6#2 |--> .. synthesized DNS64 AAAA addrinfo(s)

    // +-------------+   +-------------+

    //                   ^

    //                   |

    //                   cur6: current worked-on synthesized addrinfo

    //

    for (const addrinfo* cur4 = head4; cur4; cur4 = cur4->ai_next) {

        // Allocate a space for a synthesized AAAA addrinfo. Note that the addrinfo and sockaddr

        // occupy one contiguous block of memory and are allocated and freed as a single block.

        // See get_ai and freeaddrinfo in packages/modules/DnsResolver/getaddrinfo.cpp.

        addrinfo* sa = (addrinfo*)calloc(1, sizeof(addrinfo) + sizeof(sockaddr_in6));

        if (sa == nullptr) {

            LOG(ERROR) << "allocate memory failed for synthesized result";

            freeaddrinfo(head6);

            return false;

        }



        // Initialize the synthesized AAAA addrinfo by the queried A addrinfo. The ai_addr will be

        // set lately.

        sa->ai_flags = cur4->ai_flags;

        sa->ai_family = AF_INET6;

        sa->ai_socktype = cur4->ai_socktype;

        sa->ai_protocol = cur4->ai_protocol;

        sa->ai_addrlen = sizeof(sockaddr_in6);

        sa->ai_addr = (sockaddr*)(sa + 1);

        sa->ai_canonname = nullptr;

        sa->ai_next = nullptr;



        if (cur4->ai_canonname != nullptr) {

            sa->ai_canonname = strdup(cur4->ai_canonname);

            if (sa->ai_canonname == nullptr) {

                LOG(ERROR) << "allocate memory failed for canonname";

                freeaddrinfo(sa);

                freeaddrinfo(head6);

                return false;

            }

        }



        // Synthesize /96 NAT64 prefix in place. The space has reserved by get_ai() in

        // system/netd/resolv/getaddrinfo.cpp.

        // Synthesize /96 NAT64 prefix with the queried IPv4 address.

        const sockaddr_in* sin4 = (sockaddr_in*)cur4->ai_addr;

        sockaddr_in6* sin6 = (sockaddr_in6*)sa->ai_addr;

        sin6->sin6_addr = v6prefix->sin6_addr;

        sin6->sin6_addr.s6_addr32[3] = sinOriginal.sin_addr.s_addr;

        sin6->sin6_addr.s6_addr32[3] = sin4->sin_addr.s_addr;

        sin6->sin6_family = AF_INET6;

        sin6->sin6_port = sinOriginal.sin_port;

        ai->ai_addrlen = sizeof(struct sockaddr_in6);

        ai->ai_family = AF_INET6;

        sin6->sin6_port = sin4->sin_port;



        // If the synthesized list is empty, this becomes the first element.

        if (head6 == nullptr) {

            head6 = sa;

        }



        // Add this element to the end of the synthesized list.

        if (cur6 != nullptr) {

            cur6->ai_next = sa;

        }

        cur6 = sa;



        if (WOULD_LOG(VERBOSE)) {

            char buf[INET6_ADDRSTRLEN];  // big enough for either IPv4 or IPv6

            inet_ntop(AF_INET, &sinOriginal.sin_addr.s_addr, buf, sizeof(buf));

            inet_ntop(AF_INET, &sin4->sin_addr.s_addr, buf, sizeof(buf));

            LOG(VERBOSE) << __func__ << ": DNS A record: " << buf;

            inet_ntop(AF_INET6, &v6prefix->sin6_addr, buf, sizeof(buf));

            LOG(VERBOSE) << __func__ << ": NAT64 prefix: " << buf;
@@ -554,7 +619,31 @@ bool synthesizeNat64PrefixWithARecord(const netdutils::IPPrefix& prefix, addrinf 
            LOG(VERBOSE) << __func__ << ": DNS64 Synthesized AAAA record: " << buf;

        }

    }

    logDnsQueryResult(result);



    // Simply concatenate the synthesized AAAA addrinfo list and the queried A addrinfo list when

    // AF_UNSPEC is specified. Prefer that synthesized IPv6 addresses have higher precedence than

    // IPv4 addresses because having a NAT64 prefix implies that there is an IPv6-only network.

    // Note that head6 and cur6 should be non-null because there was at least one IPv4 address

    // synthesized.

    // TODO: Sort the concatenated addresses by RFC 6724 section 2.1. Note that the

    // socket type and protocol may be considered as well. Currently, resolv_getaddrinfo() calls

    // explore_fqdn() times by the different items of explore_options. It means that

    // _rfc6724_sort() only sorts the results in each explore_options and concatenates each results

    // into one. For example, getaddrinfo() is called with null hints for a domain name which has

    // both IPv4 and IPv6 addresses. The address order of the result addrinfo may be:

    //     2001:db8::102:304 (socktype=2, protocol=17) -> 1.2.3.4 (socktype=2, protocol=17) ->

    //     2001:db8::102:304 (socktype=1, protocol=6) -> 1.2.3.4 (socktype=1, protocol=6)

    // In above example, the first two results come from one explore option and the last two come

    // from another one. They are sorted first, and then concatenate together to be the result.

    // See also resolv_getaddrinfo in packages/modules/DnsResolver/getaddrinfo.cpp.

    if (unspecWantedButNoIPv6) {

        cur6->ai_next = head4;

    } else {

        freeaddrinfo(head4);

    }

    *res = head6;



    logDnsQueryResult(*res);

    return true;

}
@@ -713,7 +802,7 @@ void DnsProxyListener::GetAddrInfoHandler::doDns64Synthesis(int32_t* rv, addrinf 
        }

    }



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

    if (!synthesizeNat64PrefixWithARecord(prefix, res, unspecWantedButNoIPv6)) {

        if (ipv6WantedButNoData) {

            // If caller wants IPv6 answers but no data and failed to synthesize IPv6 answers,

            // don't return the IPv4 answers.

tests/resolv_integration_test.cpp

+14 −12
Original line number Diff line number Diff line
@@ -3090,7 +3090,7 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64Synthesize) { 
    // Expect that there are two queries, one AAAA (which returns no records) and one A

    // (which returns 1.2.3.4).

    EXPECT_EQ(2U, GetNumQueries(dns, host_name));

    EXPECT_EQ(ToString(result), "64:ff9b::102:304");

    EXPECT_THAT(ToStrings(result), testing::ElementsAre("64:ff9b::102:304", "1.2.3.4"));



    // Stopping NAT64 prefix discovery disables synthesis.

    EXPECT_TRUE(mDnsClient.resolvService()->stopPrefix64Discovery(TEST_NETID).isOk());
@@ -3166,7 +3166,8 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64SynthesizeMultiAnswers) { 


    // Synthesize AAAA if there's no AAAA answer and AF_UNSPEC is specified.

    EXPECT_THAT(ToStrings(result),

                testing::ElementsAre("64:ff9b::102:304", "64:ff9b::808:808", "64:ff9b::5175:15ca"));

                testing::ElementsAre("64:ff9b::102:304", "64:ff9b::808:808", "64:ff9b::5175:15ca",

                                     "1.2.3.4", "8.8.8.8", "81.117.21.202"));

}



TEST_F(ResolverTest, GetAddrInfo_Dns64Canonname) {
@@ -3199,8 +3200,8 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64Canonname) { 
            return fmt::format("family={}, flags={}", family, flags);

        }

    } testConfigs[]{

        {AF_UNSPEC,            0, {"64:ff9b::102:304"}, nullptr},

        {AF_UNSPEC, AI_CANONNAME, {"64:ff9b::102:304"}, "v4only.example.com"},

        {AF_UNSPEC,            0, {"64:ff9b::102:304", "1.2.3.4"}, nullptr},

        {AF_UNSPEC, AI_CANONNAME, {"64:ff9b::102:304", "1.2.3.4"}, "v4only.example.com"},

        {AF_INET6,             0, {"64:ff9b::102:304"}           , nullptr},

        {AF_INET6,  AI_CANONNAME, {"64:ff9b::102:304"}           , "v4only.example.com"},

    };
@@ -3213,12 +3214,12 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64Canonname) { 
                .ai_family = config.family, .ai_flags = config.flags, .ai_socktype = SOCK_DGRAM};

        ScopedAddrinfo result = safe_getaddrinfo("v4only", nullptr, &hints);

        ASSERT_TRUE(result != nullptr);

        EXPECT_EQ(ToString(result), "64:ff9b::102:304");

        const auto* ai = result.get();

        ASSERT_TRUE(ai != nullptr);

        EXPECT_THAT(ToStrings(result), testing::ElementsAreArray(config.expectedAddresses));

        for (const auto* ai = result.get(); ai != nullptr; ai = ai->ai_next) {

            EXPECT_STREQ(ai->ai_canonname, config.expectedCanonname);

        }

    }

}



TEST_F(ResolverTest, GetAddrInfo_Dns64QuerySpecified) {

    constexpr char listen_addr[] = "::1";
@@ -3308,7 +3309,7 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64QueryUnspecifiedNoV6) { 
    EXPECT_EQ(2U, GetNumQueries(dns, host_name));



    // Synthesize AAAA if there's no AAAA answer and AF_UNSPEC is specified.

    EXPECT_EQ(ToString(result), "64:ff9b::102:304");

    EXPECT_THAT(ToStrings(result), testing::ElementsAre("64:ff9b::102:304", "1.2.3.4"));

}



TEST_F(ResolverTest, GetAddrInfo_Dns64QuerySpecialUseIPv4Addresses) {
@@ -3407,7 +3408,8 @@ TEST_F(ResolverTest, GetAddrInfo_Dns64QueryWithNullArgumentHints) { 
    ScopedAddrinfo result = safe_getaddrinfo("v4only", nullptr, nullptr);

    EXPECT_TRUE(result != nullptr);

    EXPECT_LE(2U, GetNumQueries(dns, host_name));

    EXPECT_EQ(ToString(result), "64:ff9b::102:304");

    EXPECT_THAT(ToStrings(result),

                testing::ElementsAre("64:ff9b::102:304", "64:ff9b::102:304", "1.2.3.4", "1.2.3.4"));

    dns.clearQueries();



    // Do not synthesize AAAA if there's at least one AAAA answer.