DO NOT MERGE: Let netd to use the new set_nameservers_for_net call.

Also add more test for netd's resolver.

(cherry picked from commit 12f6baf16328cdeea8f079616c2c44ac28f82496)

Change-Id: I446f11b3462522ec3a18c2a3ec9401ad6cf77e8b
diff --git a/tests/netd_test.cpp b/tests/netd_test.cpp
index c679dd2..3983abc 100644
--- a/tests/netd_test.cpp
+++ b/tests/netd_test.cpp
@@ -21,9 +21,14 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include <cutils/sockets.h>
+#include <android-base/stringprintf.h>
 #include <private/android_filesystem_config.h>
+
+#include <thread>
+
 #include "NetdClient.h"
 
 #include <gtest/gtest.h>
@@ -32,23 +37,19 @@
 #include <testUtil.h>
 
 #include "dns_responder.h"
+#include "resolv_params.h"
+
+using android::base::StringPrintf;
+using android::base::StringAppendF;
 
 // TODO: make this dynamic and stop depending on implementation details.
 #define TEST_OEM_NETWORK "oem29"
 #define TEST_NETID 30
 
-enum class ResponseCode : int {
-    // Keep in sync with
-    // frameworks/base/services/java/com/android/server/NetworkManagementService.java
-    CommandOkay               = 200,
-    DnsProxyQueryResult       = 222,
-
-    DnsProxyOperationFailed   = 401,
-
-    CommandSyntaxError        = 500,
-    CommandParameterError     = 501
-};
-
+// The only response code used in this test, see
+// frameworks/base/services/java/com/android/server/NetworkManagementService.java
+// for others.
+static constexpr int ResponseCodeOK = 200;
 
 // Returns ResponseCode.
 int netdCommand(const char* sockname, const char* command) {
@@ -80,16 +81,15 @@
 }
 
 
-bool expectNetdResult(ResponseCode code, const char* sockname, const char* format, ...) {
+bool expectNetdResult(int expected, const char* sockname, const char* format, ...) {
     char command[256];
     va_list args;
     va_start(args, format);
     vsnprintf(command, sizeof(command), format, args);
     va_end(args);
     int result = netdCommand(sockname, command);
-    int rc = static_cast<int>(code);
-    EXPECT_EQ(rc, result) << command;
-    return (200 <= rc && rc < 300);
+    EXPECT_EQ(expected, result) << command;
+    return (200 <= expected && expected < 300);
 }
 
 
@@ -110,7 +110,7 @@
 
     void SetupOemNetwork() {
         netdCommand("netd", "network destroy " TEST_OEM_NETWORK);
-        if (expectNetdResult(ResponseCode::CommandOkay, "netd",
+        if (expectNetdResult(ResponseCodeOK, "netd",
                              "network create %s", TEST_OEM_NETWORK)) {
             oemNetId = TEST_NETID;
         }
@@ -120,67 +120,123 @@
 
     void TearDownOemNetwork() {
         if (oemNetId != -1) {
-            expectNetdResult(ResponseCode::CommandOkay, "netd",
+            expectNetdResult(ResponseCodeOK, "netd",
                              "network destroy %s", TEST_OEM_NETWORK);
         }
     }
 
-    bool SetResolverForNetwork(const char* address) const {
-        return
-            expectNetdResult(ResponseCode::CommandOkay, "netd",
-                             "resolver setnetdns %d \"example.com\" %s", oemNetId,
-                             address) &&
-            FlushCache();
+    bool SetResolversForNetwork(const std::vector<std::string>& searchDomains,
+            const std::vector<std::string>& servers, const std::string& params) {
+        // No use case for empty domains / servers (yet).
+        if (searchDomains.empty() || servers.empty()) return false;
+
+        std::string cmd = StringPrintf("resolver setnetdns %d \"%s", oemNetId,
+                searchDomains[0].c_str());
+        for (size_t i = 1 ; i < searchDomains.size() ; ++i) {
+            cmd += " ";
+            cmd += searchDomains[i];
+        }
+        cmd += "\" ";
+
+        cmd += servers[0];
+        for (size_t i = 1 ; i < servers.size() ; ++i) {
+            cmd += " ";
+            cmd += servers[i];
+        }
+
+        if (!params.empty()) {
+            cmd += " --params \"";
+            cmd += params;
+            cmd += "\"";
+        }
+
+        int rv = netdCommand("netd", cmd.c_str());
+        std::cout << "command: '" << cmd << "', rv = " << rv << "\n";
+        if (rv != ResponseCodeOK) {
+            return false;
+        }
+        return true;
     }
 
     bool FlushCache() const {
-        return expectNetdResult(ResponseCode::CommandOkay, "netd",
-                                "resolver flushnet %d", oemNetId);
+        return expectNetdResult(ResponseCodeOK, "netd", "resolver flushnet %d", oemNetId);
     }
 
-    std::string ToString(const hostent* result) const {
-        if (result == nullptr) return std::string();
-        return std::string(result->h_name);
+    std::string ToString(const hostent* he) const {
+        if (he == nullptr) return "<null>";
+        char buffer[INET6_ADDRSTRLEN];
+        if (!inet_ntop(he->h_addrtype, he->h_addr_list[0], buffer, sizeof(buffer))) {
+            return "<invalid>";
+        }
+        return buffer;
     }
 
-    std::string ToString(const addrinfo* result) const {
-        if (!result)
+    std::string ToString(const addrinfo* ai) const {
+        if (!ai)
             return "<null>";
-        sockaddr_in* addr = reinterpret_cast<sockaddr_in*>(result->ai_addr);
-        return std::string(inet_ntoa(addr->sin_addr));
+        for (const auto* aip = ai ; aip != nullptr ; aip = aip->ai_next) {
+            char host[NI_MAXHOST];
+            int rv = getnameinfo(aip->ai_addr, aip->ai_addrlen, host, sizeof(host), nullptr, 0,
+                    NI_NUMERICHOST);
+            if (rv != 0)
+                return gai_strerror(rv);
+            return host;
+        }
+        return "<invalid>";
+    }
+
+    size_t GetNumQueries(const test::DNSResponder& dns, const char* name) const {
+        auto queries = dns.queries();
+        size_t found = 0;
+        for (const auto& p : queries) {
+            std::cout << "query " << p.first << "\n";
+            if (p.first == name) {
+                ++found;
+            }
+        }
+        return found;
+    }
+
+    size_t GetNumQueriesForType(const test::DNSResponder& dns, ns_type type,
+            const char* name) const {
+        auto queries = dns.queries();
+        size_t found = 0;
+        for (const auto& p : queries) {
+            std::cout << "query " << p.first << "\n";
+            if (p.second == type && p.first == name) {
+                ++found;
+            }
+        }
+        return found;
     }
 
     int pid;
     int uid;
     int oemNetId = -1;
+    const std::vector<std::string> mDefaultSearchDomains = { "example.com" };
+    // <sample validity in s> <success threshold in percent> <min samples> <max samples>
+    const std::string mDefaultParams = "300 25 8 8";
 };
 
-
 TEST_F(ResolverTest, GetHostByName) {
     const char* listen_addr = "127.0.0.3";
     const char* listen_srv = "53";
-    test::DNSResponder resp(listen_addr, listen_srv, 250,
-                            ns_rcode::ns_r_servfail);
-    resp.addMapping("hello.example.com.", ns_type::ns_t_a, "1.2.3.3");
-    ASSERT_TRUE(resp.startServer());
-    ASSERT_TRUE(SetResolverForNetwork(listen_addr));
+    const char* host_name = "hello.example.com.";
+    test::DNSResponder dns(listen_addr, listen_srv, 250, ns_rcode::ns_r_servfail, 1.0);
+    dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.3");
+    ASSERT_TRUE(dns.startServer());
+    std::vector<std::string> servers = { listen_addr };
+    ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, servers, mDefaultParams));
 
-    resp.clearQueries();
+    dns.clearQueries();
     const hostent* result = gethostbyname("hello");
-    auto queries = resp.queries();
-    size_t found = 0;
-    for (const auto& p : queries) {
-        if (p.second == ns_type::ns_t_a && p.first == "hello.example.com.") {
-            ++found;
-        }
-    }
-    EXPECT_EQ(1U, found);
+    EXPECT_EQ(1U, GetNumQueriesForType(dns, ns_type::ns_t_a, host_name));
     ASSERT_FALSE(result == nullptr);
     ASSERT_EQ(4, result->h_length);
     ASSERT_FALSE(result->h_addr_list[0] == nullptr);
-    EXPECT_EQ("hello.example.com", ToString(result));
+    EXPECT_EQ("1.2.3.3", ToString(result));
     EXPECT_TRUE(result->h_addr_list[1] == nullptr);
-    resp.stopServer();
+    dns.stopServer();
 }
 
 TEST_F(ResolverTest, GetAddrInfo) {
@@ -188,63 +244,50 @@
 
     const char* listen_addr = "127.0.0.4";
     const char* listen_srv = "53";
-    test::DNSResponder resp(listen_addr, listen_srv, 250,
-                            ns_rcode::ns_r_servfail);
-    resp.addMapping("howdie.example.com.", ns_type::ns_t_a, "1.2.3.4");
-    resp.addMapping("howdie.example.com.", ns_type::ns_t_aaaa, "::1.2.3.4");
-    ASSERT_TRUE(resp.startServer());
-    ASSERT_TRUE(SetResolverForNetwork(listen_addr));
+    const char* host_name = "howdie.example.com.";
+    test::DNSResponder dns(listen_addr, listen_srv, 250,
+                           ns_rcode::ns_r_servfail, 1.0);
+    dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.4");
+    dns.addMapping(host_name, ns_type::ns_t_aaaa, "::1.2.3.4");
+    ASSERT_TRUE(dns.startServer());
+    std::vector<std::string> servers = { listen_addr };
+    ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, servers, mDefaultParams));
 
-    resp.clearQueries();
+    dns.clearQueries();
     EXPECT_EQ(0, getaddrinfo("howdie", nullptr, nullptr, &result));
-    auto queries = resp.queries();
-    size_t found = 0;
-    for (const auto& p : queries) {
-        if (p.first == "howdie.example.com.") {
-            ++found;
-        }
-    }
+    size_t found = GetNumQueries(dns, host_name);
     EXPECT_LE(1U, found);
     // Could be A or AAAA
     std::string result_str = ToString(result);
-    EXPECT_TRUE(result_str == "1.2.3.4" || result_str == "::1.2.3.4");
+    EXPECT_TRUE(result_str == "1.2.3.4" || result_str == "::1.2.3.4")
+        << ", result_str='" << result_str << "'";
     if (result) freeaddrinfo(result);
     result = nullptr;
 
     // Verify that it's cached.
     size_t old_found = found;
     EXPECT_EQ(0, getaddrinfo("howdie", nullptr, nullptr, &result));
-    queries = resp.queries();
-    found = 0;
-    for (const auto& p : queries) {
-        if (p.first == "howdie.example.com.") {
-            ++found;
-        }
-    }
+    found = GetNumQueries(dns, host_name);
+    EXPECT_LE(1U, found);
     EXPECT_EQ(old_found, found);
     result_str = ToString(result);
-    EXPECT_TRUE(result_str == "1.2.3.4" || result_str == "::1.2.3.4");
+    EXPECT_TRUE(result_str == "1.2.3.4" || result_str == "::1.2.3.4")
+        << result_str;
     if (result) freeaddrinfo(result);
     result = nullptr;
 
     // Verify that cache can be flushed.
-    resp.clearQueries();
+    dns.clearQueries();
     ASSERT_TRUE(FlushCache());
-    resp.addMapping("howdie.example.com.", ns_type::ns_t_a, "1.2.3.44");
-    resp.addMapping("howdie.example.com.", ns_type::ns_t_aaaa, "::1.2.3.44");
+    dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.44");
+    dns.addMapping(host_name, ns_type::ns_t_aaaa, "::1.2.3.44");
 
     EXPECT_EQ(0, getaddrinfo("howdie", nullptr, nullptr, &result));
-    queries = resp.queries();
-    found = 0;
-    for (const auto& p : queries) {
-        if (p.first == "howdie.example.com.") {
-            ++found;
-        }
-    }
-    EXPECT_LE(1U, found);
+    EXPECT_LE(1U, GetNumQueries(dns, host_name));
     // Could be A or AAAA
     result_str = ToString(result);
-    EXPECT_TRUE(result_str == "1.2.3.44" || result_str == "::1.2.3.44");
+    EXPECT_TRUE(result_str == "1.2.3.44" || result_str == "::1.2.3.44")
+        << ", result_str='" << result_str << "'";
     if (result) freeaddrinfo(result);
 }
 
@@ -253,24 +296,133 @@
 
     const char* listen_addr = "127.0.0.5";
     const char* listen_srv = "53";
-    test::DNSResponder resp(listen_addr, listen_srv, 250,
-                            ns_rcode::ns_r_servfail);
-    resp.addMapping("hola.example.com.", ns_type::ns_t_a, "1.2.3.5");
-    ASSERT_TRUE(resp.startServer());
-    ASSERT_TRUE(SetResolverForNetwork(listen_addr));
+    const char* host_name = "hola.example.com.";
+    test::DNSResponder dns(listen_addr, listen_srv, 250,
+                           ns_rcode::ns_r_servfail, 1.0);
+    dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.5");
+    ASSERT_TRUE(dns.startServer());
+    std::vector<std::string> servers = { listen_addr };
+    ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, servers, mDefaultParams));
 
     addrinfo hints;
     memset(&hints, 0, sizeof(hints));
     hints.ai_family = AF_INET;
     EXPECT_EQ(0, getaddrinfo("hola", nullptr, &hints, &result));
-    auto queries = resp.queries();
-    size_t found = 0;
-    for (const auto& p : queries) {
-        if (p.first == "hola.example.com.") {
-            ++found;
-        }
-    }
-    EXPECT_LE(1U, found);
+    EXPECT_EQ(1U, GetNumQueries(dns, host_name));
     EXPECT_EQ("1.2.3.5", ToString(result));
     if (result) freeaddrinfo(result);
 }
+
+TEST_F(ResolverTest, MultidomainResolution) {
+    std::vector<std::string> searchDomains = { "example1.com", "example2.com", "example3.com" };
+    const char* listen_addr = "127.0.0.6";
+    const char* listen_srv = "53";
+    const char* host_name = "nihao.example2.com.";
+    test::DNSResponder dns(listen_addr, listen_srv, 250,
+                           ns_rcode::ns_r_servfail, 1.0);
+    dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.3");
+    ASSERT_TRUE(dns.startServer());
+    std::vector<std::string> servers = { listen_addr };
+    ASSERT_TRUE(SetResolversForNetwork(searchDomains, servers, mDefaultParams));
+
+    dns.clearQueries();
+    const hostent* result = gethostbyname("nihao");
+    EXPECT_EQ(1U, GetNumQueriesForType(dns, ns_type::ns_t_a, host_name));
+    ASSERT_FALSE(result == nullptr);
+    ASSERT_EQ(4, result->h_length);
+    ASSERT_FALSE(result->h_addr_list[0] == nullptr);
+    EXPECT_EQ("1.2.3.3", ToString(result));
+    EXPECT_TRUE(result->h_addr_list[1] == nullptr);
+    dns.stopServer();
+}
+
+TEST_F(ResolverTest, GetAddrInfoV6_failing) {
+    addrinfo* result = nullptr;
+
+    const char* listen_addr0 = "127.0.0.7";
+    const char* listen_addr1 = "127.0.0.8";
+    const char* listen_srv = "53";
+    const char* host_name = "ohayou.example.com.";
+    test::DNSResponder dns0(listen_addr0, listen_srv, 250,
+                            ns_rcode::ns_r_servfail, 0.0);
+    test::DNSResponder dns1(listen_addr1, listen_srv, 250,
+                            ns_rcode::ns_r_servfail, 1.0);
+    dns0.addMapping(host_name, ns_type::ns_t_aaaa, "2001:db8::5");
+    dns1.addMapping(host_name, ns_type::ns_t_aaaa, "2001:db8::6");
+    ASSERT_TRUE(dns0.startServer());
+    ASSERT_TRUE(dns1.startServer());
+    std::vector<std::string> servers = { listen_addr0, listen_addr1 };
+    // <sample validity in s> <success threshold in percent> <min samples> <max samples>
+    unsigned sample_validity = 300;
+    int success_threshold = 25;
+    int sample_count = 8;
+    std::string params = StringPrintf("%u %d %d %d", sample_validity, success_threshold,
+            sample_count, sample_count);
+    ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, servers, params));
+
+    // Repeatedly perform resolutions for non-existing domains until MAXNSSAMPLES resolutions have
+    // reached the dns0, which is set to fail. No more requests should then arrive at that server
+    // for the next sample_lifetime seconds.
+    // TODO: This approach is implementation-dependent, change once metrics reporting is available.
+    addrinfo hints;
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_INET6;
+    for (int i = 0 ; i < sample_count ; ++i) {
+        std::string domain = StringPrintf("nonexistent%d", i);
+        getaddrinfo(domain.c_str(), nullptr, &hints, &result);
+    }
+    // Due to 100% errors for all possible samples, the server should be ignored from now on and
+    // only the second one used for all following queries, until NSSAMPLE_VALIDITY is reached.
+    dns0.clearQueries();
+    dns1.clearQueries();
+    EXPECT_EQ(0, getaddrinfo("ohayou", nullptr, &hints, &result));
+    EXPECT_EQ(0U, GetNumQueries(dns0, host_name));
+    EXPECT_EQ(1U, GetNumQueries(dns1, host_name));
+    if (result) freeaddrinfo(result);
+}
+
+TEST_F(ResolverTest, GetAddrInfoV6_concurrent) {
+    const char* listen_addr0 = "127.0.0.9";
+    const char* listen_addr1 = "127.0.0.10";
+    const char* listen_addr2 = "127.0.0.11";
+    const char* listen_srv = "53";
+    const char* host_name = "konbanha.example.com.";
+    test::DNSResponder dns0(listen_addr0, listen_srv, 250,
+                            ns_rcode::ns_r_servfail, 1.0);
+    test::DNSResponder dns1(listen_addr1, listen_srv, 250,
+                            ns_rcode::ns_r_servfail, 1.0);
+    test::DNSResponder dns2(listen_addr2, listen_srv, 250,
+                            ns_rcode::ns_r_servfail, 1.0);
+    dns0.addMapping(host_name, ns_type::ns_t_aaaa, "2001:db8::5");
+    dns1.addMapping(host_name, ns_type::ns_t_aaaa, "2001:db8::6");
+    dns2.addMapping(host_name, ns_type::ns_t_aaaa, "2001:db8::7");
+    ASSERT_TRUE(dns0.startServer());
+    ASSERT_TRUE(dns1.startServer());
+    ASSERT_TRUE(dns2.startServer());
+    const std::vector<std::string> servers = { listen_addr0, listen_addr1, listen_addr2 };
+    std::vector<std::thread> threads(10);
+    for (std::thread& thread : threads) {
+       thread = std::thread([this, &servers, &dns0, &dns1, &dns2]() {
+            unsigned delay = arc4random_uniform(1*1000*1000); // <= 1s
+            usleep(delay);
+            std::vector<std::string> serverSubset;
+            for (const auto& server : servers) {
+                if (arc4random_uniform(2)) {
+                    serverSubset.push_back(server);
+                }
+            }
+            if (serverSubset.empty()) serverSubset = servers;
+            ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, serverSubset,
+                    mDefaultParams));
+            addrinfo hints;
+            memset(&hints, 0, sizeof(hints));
+            hints.ai_family = AF_INET6;
+            addrinfo* result = nullptr;
+            int rv = getaddrinfo("konbanha", nullptr, &hints, &result);
+            EXPECT_EQ(0, rv) << "error [" << rv << "] " << gai_strerror(rv);
+        });
+    }
+    for (std::thread& thread : threads) {
+        thread.join();
+    }
+}