我正在尝试通过目标 c 的 telnet 连接到 Cisco C40 编解码器。在我的计算机上使用终端时，我得到：
密码：
但是，在进行套接字连接时，需要进行 telnet 协商。我就是这样，但由于某种原因，我无法进入上面的“密码：”提示。
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag
{
NSLog(@"RECEIVE BUFFER %@",data);
//store read bytes to rawData
self.rawData = [[NSMutableData alloc] initWithData:data];
//cast bytes
const uint8_t *bytes = [self.rawData bytes];
//go through rawdata format and save it to networkbuffer
for (int i =0; i < [self.rawData length]; i++)
{
if (![[NSString stringWithFormat:@"%02X", bytes[i]]isEqual:@"0D"])
{
[self.networkBuffer addObject:[NSString stringWithFormat:@"%02X", bytes[i]]];
}
}
//negotiate any telnet protocal stuff (just accept options )
//example:
//FF:FD:18 returns FF:FB:18
while([[self.networkBuffer objectAtIndex:0]isEqualToString:@"FF"] && [[self.networkBuffer objectAtIndex:1]isEqualToString:@"FD"] ) {
// NSLog(@"HERE");
NSData * tempData =[data subdataWithRange:NSMakeRange(0, 3)];
NSMutableData * tempMutData = [NSMutableData dataWithData:tempData];
const unsigned char replacement[] = {
0xFC
};
[tempMutData replaceBytesInRange:NSMakeRange(1, 1) withBytes:replacement];
[self sendCommand:tempMutData];
data = [data subdataWithRange:NSMakeRange(3, [data length]-3)];
self.networkBuffer = [NSMutableArray arrayWithArray:[self.networkBuffer subarrayWithRange:NSMakeRange(3, [self.networkBuffer count]-3)]];
// NSLog(@"network buffer after removal: %@", data);
if ([self.networkBuffer count]<3) {
[self.networkBuffer insertObject:@" " atIndex:0];
}
}
//decode from bytes to text
for ( NSString * component in self.networkBuffer)
{
int value = 0;
sscanf([component cStringUsingEncoding:NSASCIIStringEncoding], "%x", &value);
[self.dataString appendFormat:@"%c", (char)value];
NSLog(@"data byte: %c",(char)value);
}
[self telnetResponse:self.dataString];
[self.networkBuffer removeAllObjects];
[self.socket readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];//CRLFData
}
这是我接收和发送的 telnet 协商选项的细分：
服务器发给我：
FF,FD,18 (0x18 = 24dec) (Do 终端类型)
FF,FD,20 (0x20 = 32dec) (做终端速度)
FF,FD,23 (0x23 = 35dec) (Do X 显示位置)
FF,FD,27 (0x27 = 39dec)（执行新环境选项）
我对无效响应的尝试（没有提示进一步输入）：
FF,FC,18 (0x18 = 24dec) (Wont 终端类型)
FF,FC,20 (0x20 = 32dec) (Wont 终端速度)
FF,FC,23 (0x23 = 35dec) (Wont X 显示位置)
FF,FC,27 (0x27 = 39dec) （没有新环境选项）
如果您查看代码，您会看到我正在检查 FF，如果是这样，则以类似的字节响应（用 FC 替换 FD），希望不会接受这些选项，但这似乎不起作用。
对我有帮助的链接：
https://stackoverflow.com/a/2913991/530933
http://www.iprodeveloper.com/forums/aft/52910
更新
我用命令外壳和思科编解码器做了一个wireshark。之后我复制了那些协商设置/数据包。现在唯一的问题是我只得到回声。所以我什么也得不到，发送一个命令，然后返回一个提示和我的文本。（例如，一无所获-发送用户名“admin”-返回“login：admin”）因此我的意思是只获得回声。我应该得到一个提示“登录：”然后发送“管理员”然后它应该提示我输入密码。
这是我在连接时发送的协商选项：
//will terminal type
//will negotiate about window size
const unsigned char nineteen[] = {
0xFF, 0xFB, 0x18, 0xFF, 0xFB, 0x1F
};
self.dataToBeSent = [[NSData alloc]initWithBytes:nineteen length:sizeof(nineteen)];
[self sendCommand:self.dataToBeSent];
//wont terminal speed
//wont X display location
//will new environment option
const unsigned char twenty[] = {
0xFF, 0xFC, 0x20, 0xFF, 0xFC, 0x23, 0xFF, 0xFB, 0x27
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twenty length:sizeof(twenty)];
[self sendCommand:self.dataToBeSent];
//Suboption being: negotiate about window size
//end
const unsigned char twentyOne[] = {
//0xFF,0xFC, 0x18
0xFF, 0xFA, 0x1F, 0x00, 0x50, 0x00, 0x19, 0xFF, 0xF0
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentyOne length:sizeof(twentyOne)];
[self sendCommand:self.dataToBeSent];
//new enviroment option
//end
const unsigned char twentyThree[] = {
0xFF,0xFA, 0x27, 0x00, 0xFF, 0xF0
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentyThree length:sizeof(twentyThree)];
[self sendCommand:self.dataToBeSent];
//Terminal Type (ANSI)
//end
const unsigned char twentySeven[] = {
0xFF,0xFA, 0x18, 0x00, 0x41, 0x4E, 0x53, 0x49, 0xFF, 0xF0
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentySeven length:sizeof(twentySeven)];
[self sendCommand:self.dataToBeSent];
//do suppress go ahead
const unsigned char twentyEight[] = {
0xFF, 0xFD, 0x03
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentyEight length:sizeof(twentyEight)];
[self sendCommand:self.dataToBeSent];
//will echo
//dont status
//wont remote flow control
const unsigned char twentyFour[] = {
0xFF, 0xFB, 0x01, 0xFF, 0xFE, 0x05, 0xFF,0xFC, 0x21
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentyFour length:sizeof(twentyFour)];
[self sendCommand:self.dataToBeSent];
//wont echo
const unsigned char twentyFive[] = {
0xFF, 0xFC, 0x01
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentyFive length:sizeof(twentyFive)];
[self sendCommand:self.dataToBeSent];
//Do echo
const unsigned char twentySix[] = {
0xFF,0xFD, 0x01
};
self.dataToBeSent = [[NSData alloc]initWithBytes:twentySix length:sizeof(twentySix)];
[self sendCommand:self.dataToBeSent];