如何从CFStream ( iOS )中获取远程地址？

Question

我在我的CFStreams应用程序中使用iOS连接主机名，如下所示：

CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)host, port, &readStream, &writeStream);

outputStream = (__bridge NSOutputStream *)writeStream;
inputStream = (__bridge NSInputStream *)readStream;

但是我想知道如何从流中获取host的远程IP地址？

Answer 1

您可以获得文件描述符( Apple称之为“本机句柄”)，并使用典型的POSIX网络命令获取地址：

从流中获取文件描述符：

CFDataRef handleData = (CFDataRef)CFReadStreamCopyProperty((__bridge CFReadStreamRef) inputStream, kCFStreamPropertySocketNativeHandle);
long length = CFDataGetLength(handleData);
uint8_t * buffer = malloc(length);
CFDataGetBytes(handleData, CFRangeMake(0, length), buffer);
int sock_fd = (int)*buffer;

获取该文件描述符的远程地址：

struct sockaddr_storage addr;
socklen_t addr_len = sizeof(addr);
getpeername(socket, (struct sockaddr *)&addr, &addr_len);
NSString * remoteAddr;
if (addr.ss_family == AF_INET) {
    char addressString[INET_ADDRSTRLEN];
    inet_ntop(AF_INET, &((struct sockaddr_in *)&addr)->sin_addr, addressString, INET_ADDRSTRLEN);
    remoteAddr = [[NSString alloc] initWithUTF8String:addressString];
} else if (addr.ss_family == AF_INET6) {
    char addressString[INET6_ADDRSTRLEN];
    inet_ntop(AF_INET6, &((struct sockaddr_in6 *)&addr)->sin6_addr, addressString, INET6_ADDRSTRLEN);
    remoteAddr = [[NSString alloc] initWithUTF8String:addressString];
}
free(buffer);

// Now you have remoteAddr which will be a
// string representation of a IPv4 or IPv6 address!
NSLog(@"Remote Address: %@", remoteAddr);