diff --git a/MSDKDns.xcodeproj/project.pbxproj b/MSDKDns.xcodeproj/project.pbxproj index 0c9df20..6457b33 100644 --- a/MSDKDns.xcodeproj/project.pbxproj +++ b/MSDKDns.xcodeproj/project.pbxproj @@ -38,12 +38,12 @@ 54EA82232760890B005F68A9 /* AttaReport.m in Sources */ = {isa = PBXBuildFile; fileRef = 54EA82212760890B005F68A9 /* AttaReport.m */; }; 54EA822427608A55005F68A9 /* AttaReport.h in Headers */ = {isa = PBXBuildFile; fileRef = 54EA82202760890B005F68A9 /* AttaReport.h */; }; 54EA822527608A58005F68A9 /* AttaReport.m in Sources */ = {isa = PBXBuildFile; fileRef = 54EA82212760890B005F68A9 /* AttaReport.m */; }; - 5FE4BAB4289A4E4700C7A944 /* HttpdnsSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5FE4BAB1289A4E4700C7A944 /* HttpdnsSpeedTester.h */; }; - 5FE4BAB5289A4E4700C7A944 /* HttpdnsSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5FE4BAB1289A4E4700C7A944 /* HttpdnsSpeedTester.h */; }; - 5FE4BAB6289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5FE4BAB2289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h */; }; - 5FE4BAB7289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5FE4BAB2289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h */; }; - 5FE4BAB8289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m in Sources */ = {isa = PBXBuildFile; fileRef = 5FE4BAB3289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m */; }; - 5FE4BAB9289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m in Sources */ = {isa = PBXBuildFile; fileRef = 5FE4BAB3289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m */; }; + 5F5DAF4E28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5F5DAF4B28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h */; }; + 5F5DAF4F28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5F5DAF4B28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h */; }; + 5F5DAF5028A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m in Sources */ = {isa = PBXBuildFile; fileRef = 5F5DAF4C28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m */; }; + 5F5DAF5128A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m in Sources */ = {isa = PBXBuildFile; fileRef = 5F5DAF4C28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m */; }; + 5F5DAF5228A525E300BF5B79 /* MSDKDnsSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5F5DAF4D28A525E300BF5B79 /* MSDKDnsSpeedTester.h */; }; + 5F5DAF5328A525E300BF5B79 /* MSDKDnsSpeedTester.h in Headers */ = {isa = PBXBuildFile; fileRef = 5F5DAF4D28A525E300BF5B79 /* MSDKDnsSpeedTester.h */; }; C8EBE7D3256664C500BEFEEC /* aes.h in Headers */ = {isa = PBXBuildFile; fileRef = C8EBE7D1256664C400BEFEEC /* aes.h */; }; C8EBE7D4256664C500BEFEEC /* aes.mm in Sources */ = {isa = PBXBuildFile; fileRef = C8EBE7D2256664C500BEFEEC /* aes.mm */; }; C8EBE7F4256668A300BEFEEC /* libc++.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = C8EBE7DA2566675800BEFEEC /* libc++.tbd */; }; @@ -110,9 +110,9 @@ 54EA81F1275478D1005F68A9 /* httpdnsIps.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = httpdnsIps.h; sourceTree = ""; }; 54EA82202760890B005F68A9 /* AttaReport.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AttaReport.h; sourceTree = ""; }; 54EA82212760890B005F68A9 /* AttaReport.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = AttaReport.m; sourceTree = ""; }; - 5FE4BAB1289A4E4700C7A944 /* HttpdnsSpeedTester.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = HttpdnsSpeedTester.h; sourceTree = ""; }; - 5FE4BAB2289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = HttpdnsTCPSpeedTester.h; sourceTree = ""; }; - 5FE4BAB3289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = HttpdnsTCPSpeedTester.m; sourceTree = ""; }; + 5F5DAF4B28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSDKDnsTCPSpeedTester.h; sourceTree = ""; }; + 5F5DAF4C28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSDKDnsTCPSpeedTester.m; sourceTree = ""; }; + 5F5DAF4D28A525E300BF5B79 /* MSDKDnsSpeedTester.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSDKDnsSpeedTester.h; sourceTree = ""; }; C8EBE7D1256664C400BEFEEC /* aes.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = aes.h; sourceTree = ""; }; C8EBE7D2256664C500BEFEEC /* aes.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = aes.mm; sourceTree = ""; }; C8EBE7DA2566675800BEFEEC /* libc++.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = "libc++.tbd"; path = "Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/lib/libc++.tbd"; sourceTree = DEVELOPER_DIR; }; @@ -174,9 +174,9 @@ 4497F8BC1B46306200D51391 /* MSDKDnsPrivate.h */, 504F54381ECAF89F001BD7A9 /* MSDKDnsHttpMessageTools.h */, 504F54391ECAF89F001BD7A9 /* MSDKDnsHttpMessageTools.m */, - 5FE4BAB1289A4E4700C7A944 /* HttpdnsSpeedTester.h */, - 5FE4BAB2289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h */, - 5FE4BAB3289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m */, + 5F5DAF4D28A525E300BF5B79 /* MSDKDnsSpeedTester.h */, + 5F5DAF4B28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h */, + 5F5DAF4C28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m */, C8EBE7D1256664C400BEFEEC /* aes.h */, C8EBE7D2256664C500BEFEEC /* aes.mm */, 54EA821F2760890B005F68A9 /* Reporter */, @@ -272,18 +272,18 @@ C8EBE7D3256664C500BEFEEC /* aes.h in Headers */, 445B36631CBD095C00BD4345 /* MSDKDnsManager.h in Headers */, 4497F8B81B4628F000D51391 /* MSDKDnsLog.h in Headers */, - 5FE4BAB4289A4E4700C7A944 /* HttpdnsSpeedTester.h in Headers */, 4455D15E1B3A5B90005BF126 /* MSDKDns.h in Headers */, 448EE4E61B329899004A2131 /* LocalDnsResolver.h in Headers */, DD5935581DDC56B200BF9348 /* HttpsDnsResolver.h in Headers */, + 5F5DAF4E28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h in Headers */, 448EE4E81B329899004A2131 /* MSDKDnsResolver.h in Headers */, 54EA82222760890B005F68A9 /* AttaReport.h in Headers */, + 5F5DAF5228A525E300BF5B79 /* MSDKDnsSpeedTester.h in Headers */, 44BFE2371CA58C3A00D7FE87 /* MSDKDnsInfoTool.h in Headers */, 502422EC2140073F0094403C /* MSDKDnsParamsManager.h in Headers */, 4497F8BD1B46306200D51391 /* MSDKDnsPrivate.h in Headers */, 444044F91B3133A30010F5D5 /* MSDKDnsService.h in Headers */, 501001F0215E1F1D003288A5 /* msdkdns_local_ip_stack.h in Headers */, - 5FE4BAB6289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h in Headers */, ); runOnlyForDeploymentPostprocessing = 0; }; @@ -297,18 +297,18 @@ 2FBE52E825E77AFE0012A0DF /* aes.h in Headers */, DD43F4A9231CC36D0000A89F /* MSDKDnsManager.h in Headers */, DD43F4AA231CC36D0000A89F /* MSDKDnsLog.h in Headers */, - 5FE4BAB5289A4E4700C7A944 /* HttpdnsSpeedTester.h in Headers */, DD43F4AB231CC36D0000A89F /* MSDKDns.h in Headers */, DD43F4AC231CC36D0000A89F /* LocalDnsResolver.h in Headers */, DD43F4AD231CC36D0000A89F /* HttpsDnsResolver.h in Headers */, + 5F5DAF4F28A525E300BF5B79 /* MSDKDnsTCPSpeedTester.h in Headers */, DD43F4AE231CC36D0000A89F /* MSDKDnsResolver.h in Headers */, 54EA822427608A55005F68A9 /* AttaReport.h in Headers */, + 5F5DAF5328A525E300BF5B79 /* MSDKDnsSpeedTester.h in Headers */, DD43F4AF231CC36D0000A89F /* MSDKDnsInfoTool.h in Headers */, DD43F4B0231CC36D0000A89F /* MSDKDnsParamsManager.h in Headers */, DD43F4B1231CC36D0000A89F /* MSDKDnsPrivate.h in Headers */, DD43F4B2231CC36D0000A89F /* MSDKDnsService.h in Headers */, DD43F4B3231CC36D0000A89F /* msdkdns_local_ip_stack.h in Headers */, - 5FE4BAB7289A4E4700C7A944 /* HttpdnsTCPSpeedTester.h in Headers */, ); runOnlyForDeploymentPostprocessing = 0; }; @@ -499,8 +499,8 @@ DD5935561DDC56B200BF9348 /* HttpsDnsResolver.m in Sources */, 445B36651CBD095C00BD4345 /* MSDKDnsManager.m in Sources */, 444044FA1B3133A30010F5D5 /* MSDKDnsService.m in Sources */, + 5F5DAF5028A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m in Sources */, 501001EE215E1F1D003288A5 /* msdkdns_local_ip_stack.cpp in Sources */, - 5FE4BAB8289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m in Sources */, 44BFE24A1CA59D9800D7FE87 /* MSDKDnsReachability.m in Sources */, C8EBE7D4256664C500BEFEEC /* aes.mm in Sources */, 445B366B1CBD1D4700BD4345 /* MSDKDnsNetworkManager.m in Sources */, @@ -522,8 +522,8 @@ DD43F498231CC36D0000A89F /* HttpsDnsResolver.m in Sources */, DD43F499231CC36D0000A89F /* MSDKDnsManager.m in Sources */, DD43F49A231CC36D0000A89F /* MSDKDnsService.m in Sources */, + 5F5DAF5128A525E300BF5B79 /* MSDKDnsTCPSpeedTester.m in Sources */, 2FBE52E925E77B000012A0DF /* aes.mm in Sources */, - 5FE4BAB9289A4E4700C7A944 /* HttpdnsTCPSpeedTester.m in Sources */, DD43F49B231CC36D0000A89F /* msdkdns_local_ip_stack.cpp in Sources */, DD43F49C231CC36D0000A89F /* MSDKDnsReachability.m in Sources */, DD43F49D231CC36D0000A89F /* MSDKDnsNetworkManager.m in Sources */, diff --git a/MSDKDns/HttpdnsTCPSpeedTester.h b/MSDKDns/HttpdnsTCPSpeedTester.h deleted file mode 100644 index eba0dea..0000000 --- a/MSDKDns/HttpdnsTCPSpeedTester.h +++ /dev/null @@ -1,13 +0,0 @@ -/** - * Copyright (c) Tencent. All rights reserved. - */ - -#import -#import "HttpdnsSpeedTester.h" - -#define HTTPDNS_SOCKET_CONNECT_TIMEOUT 10 //单位秒 -#define HTTPDNS_SOCKET_CONNECT_TIMEOUT_RTT 600000//10分钟 单位毫秒 - -@interface HttpdnsTCPSpeedTester : NSObject - -@end diff --git a/MSDKDns/MSDKDnsService.m b/MSDKDns/MSDKDnsService.m index 4b3b040..ad069e8 100644 --- a/MSDKDns/MSDKDnsService.m +++ b/MSDKDns/MSDKDnsService.m @@ -10,7 +10,7 @@ #import "MSDKDnsManager.h" #import "MSDKDnsNetworkManager.h" #import "MSDKDnsParamsManager.h" -#import "HttpdnsTCPSpeedTester.h" +#import "MSDKDnsTCPSpeedTester.h" #import "AttaReport.h" @interface MSDKDnsService () @@ -310,7 +310,7 @@ - (void)aysncUpdateIPRankingWithResult:(NSArray *)IPStrings forHost:(NSString *) } - (void)syncUpdateIPRankingWithResult:(NSArray *)IPStrings forHost:(NSString *)host { - NSArray *sortedIps = [[HttpdnsTCPSpeedTester new] ipRankingWithIPs:IPStrings host:host]; + NSArray *sortedIps = [[MSDKDnsTCPSpeedTester new] ipRankingWithIPs:IPStrings host:host]; [self updateHostManagerDictWithIPs:sortedIps host:host]; } @@ -318,7 +318,7 @@ - (void)updateHostManagerDictWithIPs:(NSArray *)IPs host:(NSString *)host { if(!IPs){ return; } - @synchronized(self) { + dispatch_async([MSDKDnsInfoTool msdkdns_queue], ^{ NSDictionary * tempDict = [[[MSDKDnsManager shareInstance] domainDict] objectForKey:host]; NSMutableDictionary *cacheDict; @@ -351,7 +351,7 @@ - (void)updateHostManagerDictWithIPs:(NSArray *)IPs host:(NSString *)host { [[MSDKDnsManager shareInstance] cacheDomainInfo:cacheDict Domain:host]; } } - } + }); } - (void)resolver:(MSDKDnsResolver *)resolver getDomainError:(NSString *)error retry:(BOOL)retry { diff --git a/MSDKDns/HttpdnsSpeedTester.h b/MSDKDns/MSDKDnsSpeedTester.h similarity index 84% rename from MSDKDns/HttpdnsSpeedTester.h rename to MSDKDns/MSDKDnsSpeedTester.h index fa24c89..e8430a9 100644 --- a/MSDKDns/HttpdnsSpeedTester.h +++ b/MSDKDns/MSDKDnsSpeedTester.h @@ -2,7 +2,7 @@ * Copyright (c) Tencent. All rights reserved. */ -@protocol HttpdnsSpeedTester +@protocol MSDKDnsSpeedTester - (float)testSpeedOf:(NSString *)ip port:(int16_t)port; - (NSArray *)ipRankingWithIPs:(NSArray *)IPs host:(NSString *)host; diff --git a/MSDKDns/MSDKDnsTCPSpeedTester.h b/MSDKDns/MSDKDnsTCPSpeedTester.h new file mode 100644 index 0000000..a6eb40c --- /dev/null +++ b/MSDKDns/MSDKDnsTCPSpeedTester.h @@ -0,0 +1,13 @@ +/** + * Copyright (c) Tencent. All rights reserved. + */ + +#import +#import "MSDKDnsSpeedTester.h" + +#define MSDKDns_SOCKET_CONNECT_TIMEOUT 10 //单位秒 +#define MSDKDns_SOCKET_CONNECT_TIMEOUT_RTT 600000//10分钟 单位毫秒 + +@interface MSDKDnsTCPSpeedTester : NSObject + +@end diff --git a/MSDKDns/HttpdnsTCPSpeedTester.m b/MSDKDns/MSDKDnsTCPSpeedTester.m similarity index 66% rename from MSDKDns/HttpdnsTCPSpeedTester.m rename to MSDKDns/MSDKDnsTCPSpeedTester.m index bdab1e1..cf2bdc3 100644 --- a/MSDKDns/HttpdnsTCPSpeedTester.m +++ b/MSDKDns/MSDKDnsTCPSpeedTester.m @@ -2,7 +2,7 @@ * Copyright (c) Tencent. All rights reserved. */ -#import "HttpdnsTCPSpeedTester.h" +#import "MSDKDnsTCPSpeedTester.h" #import "MSDKDnsParamsManager.h" #import "MSDKDnsLog.h" #import @@ -15,22 +15,11 @@ static NSString *const testSpeedKey = @"testSpeed"; static NSString *const ipKey = @"ip"; -@implementation HttpdnsTCPSpeedTester +@implementation MSDKDnsTCPSpeedTester -/*! - * 如果用户对域名提供多个端口，取任意一个端口。 - 假设：同一个域名，不同端口到达速度一致。 - 让优选逻辑，尽量少de - 15s 100s - - - IP池在2个到5个范围内，才进行测速逻辑。 - - 只在ttl未过期内测试。 - - ~~只取内存缓存，与持久化缓存逻辑不产生交集。持久化优先级更高。~~ 无法区分持久化，持久化缓存也可能参与排序。 - - 测速逻辑公开，作为最佳实践。 - - 只在 IPv4 逻辑下测试，IPv6 环境不测。 - - 开启IPv6解析结果时，不测试。 - - 测速逻辑不能增加用户计费请求次数。 - - 预加载也参与IP优选，网络请求成功就异步排序。 +/** + * + - IP池在2个到9个范围内，才进行测速逻辑。 - */ - (NSArray *)ipRankingWithIPs:(NSArray *)IPs host:(NSString *)host { @@ -61,7 +50,7 @@ @implementation HttpdnsTCPSpeedTester float testSpeed = [self testSpeedOf:ip port:port]; MSDKDNSLOG(@"%@:%hd speed is %f",ip,port,testSpeed); if (testSpeed == 0) { - testSpeed = HTTPDNS_SOCKET_CONNECT_TIMEOUT_RTT; + testSpeed = MSDKDns_SOCKET_CONNECT_TIMEOUT_RTT; } NSMutableDictionary *IPSpeed = [NSMutableDictionary dictionaryWithCapacity:2]; [IPSpeed setObject:@(testSpeed) forKey:testSpeedKey]; @@ -88,14 +77,7 @@ @implementation HttpdnsTCPSpeedTester } /** - * 本测速函数，使用linux socket connect 和select函数实现的。 基于以下原理 - * 1. 即使套接口是非阻塞的。如果连接的服务器在同一台主机上，那么在调用connect 建立连接时，连接通常会立即建立成功，我们必须处理这种情况。 - * 2. 源自Berkeley的实现(和Posix.1g)有两条与select 和非阻塞IO相关的规则： - * A. 当连接建立成功时，套接口描述符变成可写； - * B. 当连接出错时，套接口描述符变成既可读又可写。 - * @param ip 用于测速对Ip，应该是IPv4格式。 - * - * @return 测速结果，单位时毫秒，HTTPDNS_SOCKET_CONNECT_TIMEOUT_RTT 代表超时。 + * @return 测速结果，单位时毫秒，MSDKDns_SOCKET_CONNECT_TIMEOUT_RTT 代表超时。 */ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { NSString *oldIp = ip; @@ -105,10 +87,8 @@ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { int s = 0; struct sockaddr_in saddr; saddr.sin_family = AF_INET; - // MARK: - 设置端口，这里需要根据需要自定义，默认是80端口。 saddr.sin_port = htons(port); saddr.sin_addr.s_addr = inet_addr([ip UTF8String]); - //saddr.sin_addr.s_addr = inet_addr("1.1.1.123"); if( (s=socket(AF_INET, SOCK_STREAM, 0)) < 0) { MSDKDNSLOG(@"ERROR:%s:%d, create socket failed.",__FUNCTION__,__LINE__); return 0; @@ -118,9 +98,6 @@ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { //为了设置connect超时 把socket设置称为非阻塞 int flags = fcntl(s, F_GETFL,0); fcntl(s,F_SETFL, flags | O_NONBLOCK); - //对于阻塞式套接字，调用connect函数将激发TCP的三次握手过程，而且仅在连接建立成功或者出错时才返回； - //对于非阻塞式套接字，如果调用connect函数会之间返回-1（表示出错），且错误为EINPROGRESS，表示连接建立，建立启动但是尚未完成； - //如果返回0，则表示连接已经建立，这通常是在服务器和客户在同一台主机上时发生。 int i = connect(s,(struct sockaddr*)&saddr, sizeof(saddr)); if(i == 0) { //建立连接成功，返回rtt时间。 因为connect是非阻塞，所以这个时间就是一个函数执行的时间，毫秒级，没必要再测速了。 @@ -130,7 +107,7 @@ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { struct timeval tv; int valopt; socklen_t lon; - tv.tv_sec = HTTPDNS_SOCKET_CONNECT_TIMEOUT; + tv.tv_sec = MSDKDns_SOCKET_CONNECT_TIMEOUT; tv.tv_usec = 0; fd_set myset; @@ -148,7 +125,7 @@ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { if (j == 0) { MSDKDNSLOG(@"INFO:%s:%d, test rtt of (%@) timeout.",__FUNCTION__,__LINE__, oldIp); - rtt = HTTPDNS_SOCKET_CONNECT_TIMEOUT_RTT; + rtt = MSDKDns_SOCKET_CONNECT_TIMEOUT_RTT; close(s); return rtt; } @@ -159,20 +136,13 @@ - (float)testSpeedOf:(NSString *)ip port:(int16_t)port { close(s); return rtt; } - /** 对于select和非阻塞connect，注意两点： [1] 当连接成功建立时，描述符变成可写； [2] 当连接建立遇到错误时，描述符变为即可读，也可写，遇到这种情况，可调用getsockopt函数。 **/ lon = sizeof(int); //valopt 表示错误信息。 - // MARK: - 测试核心逻辑，连接后，获取错误信息，如果没有错误信息就是访问成功 - /*! - * //getsockopt函数可获取影响套接字的选项，比如SOCKET的出错信息 - * (get socket option) - */ getsockopt(s, SOL_SOCKET, SO_ERROR, (void*)(&valopt), &lon); - //如果有错误信息： if (valopt) { MSDKDNSLOG(@"ERROR:%s:%d, select function error.",__FUNCTION__,__LINE__); rtt = 0;