2012年7月10日星期二

如何使用W7100A實現Telnet伺服器(三)


在上两篇博文(如何使用W7100A實現Telnet伺服器(一)如何使用W7100A實現Telnet伺服器(二))里我们简单地介绍一下Telnet,第三章将会演示Telnet函数的具体功能,第四章将涉及到代码的分析。这篇文档中所有的示例代码都是基于Keil uVision3。
下面我们介绍第三部分(主要内容是第四章的余下的代码分析部分):


4.3 tel_input()函数
tel_input()函数用来处理Telnet终端机内的输入命令。具体每一个命令以及处理方法请参考表3.1。
void tel_input(SOCKET s)
{
uint8 xdata c;
while(1){
if((getSn_RX_RSR(s)) == 0)  break;     /*如果没有接收到的数据,断开*/
if(recv(s, &c, 1) == 0) break;     /*如果接收到的数据为0,断开*/
if(user_state == LOGOUT)  break;     /*如果用户的声明是LOGOUT, 断开*/
if(c != IAC){         /*如果接收到的数据不是控制字符*/
data_buf[buf_index++] = c;    /*保存接收到的数据到data_buf*/
putchar(c);
if(user_state == LOGOUT)  break;
if(user_state != PASSWORD){
       sprintf(buf, "%c", c);
       send(s, buf, strlen(buf));
}
if(c == '\n'){     /*如果接收到一个\n’ ASCII 代码*/
       if(buf_index > 1){
         if(data_buf[buf_index-2] == '\r')  data_buf[buf_index-2] = '\0';
         else  data_buf[buf_index-1] = '\0';
         proc_command(s);      /* 处理接收到的数据*/
         if(user_state == LOGIN) {
           sprintf(buf, "W7100>");
           send(s, buf, strlen(buf));
         }
       }
       else{
         sprintf(buf, "W7100>");
         send(s, buf, strlen(buf));
       }
       buf_index = 0;
}
continue;
}
if(recv(s, &c, 1) == 0)  break;
switch(c){            /*如果接收到一个IAC字符*/
case WILL:
if(recv(s, &c, 1) == 0)  break;
willopt(s, c);      /*调用willopt()处理WILL命令*/
break;
case WONT:
if(recv(s, &c, 1) == 0)  break;
wontopt(s, c);      /*调用wontopt()来处理WONT命令*/
break;
case DO:
if(recv(s, &c, 1) == 0)  break;
doopt(s, c);      /*调用doopt()处理DO命令*/
break;
case DONT:
if(recv(s, &c, 1) == 0)  break;
dontopt(c);      /*调用dontopt()处理DON’T命令*/
break;
case IAC:
break;
}
break;
}
return;
}
程序4.3parseMSG()函数

4.4 proc_command()函数
proc_command()函数处理在tel_input()函数中输入的命令。它定义了HELP、GET LED、LED0 ON/OFF和LED2 ON/OFF命令。对于未定义的命令它显示“BAD COMMAND”。
void proc_command(SOCKET s)
{
uint8 i;
char **cmdp, *cp;
char *help = {"HELP: Show all available commands\r\n\GET LED: Show all LED status\                  \r\nLED0 ON/OFF: Turn ON/OFF the LED0\r\nLED1 ON/OFF: Turn ON/OFF the LED1\
         \r\nLED2 ON/OFF: Turn ON/OFF the LED2\r\nEXIT: Exit from W7100 Telnet server\r\n"};
       /*Translate the first word to lower case*/
for(cp = data_buf; *cp !='\0'; cp++){
*cp = tolower(*cp);     /* 将大写字母翻译成小写字母*/
}
if(user_state == USERNAME){
strcpy(user_name, data_buf);
sprintf(buf, "Please insert your PW: ");
send(s, buf, strlen(buf));
user_state = PASSWORD;
return;
}
else if(user_state == PASSWORD){
strcpy(user_password, data_buf);
sprintf(buf, "\r\nSuccessfully connected!!\r\nImplemented Command: \
HELP, GET LED, LED0 ON/OFF, LED1 ON/OFF, LED2 ON/OFF, EXIT\r\n");
send(s, buf, strlen(buf));
user_state = LOGIN;
return;
}     /*查找表中的输入命令; 如果不表内,返回语法错误*/
for(cmdp = commands; *cmdp != NULL; cmdp++){
if(strncmp(*cmdp, data_buf, strlen(*cmdp)) == 0)     break;
}
if(*cmdp == NULL){
printf("NULL command\r\n");
sprintf(buf, "BAD command\r\n");
send(s, buf, strlen(buf));
return;
}
switch(cmdp - commands){
case HELP_CMD:         /* 处理HELP命令*/
printf("HELP_CMD\r\n");
sprintf(buf, help);
send(s, buf, strlen(buf));
break;
case GET_LED_CMD:        /*处理GET LED 命令*/
printf("GET_LED_CMD\r\n");
for(i = 0 ; i < 3 ; i++){
       sprintf(buf, "LED%bd is %s\r\n", i, ((P0 >> (i+3)) & 0x01) ? "OFF" : "ON");
       send(s, buf, strlen(buf));
}
break;
case LED0_ON_CMD:        /*处理LED0 ON命令*/
printf("LED0_ON_CMD\r\n");
sprintf(buf, "Turn ON the LED0\r\n");
send(s, buf, strlen(buf));
P0_3 = 0;       /* 将GPIO 0_3设置为0, 与低有效LED连接*/
break;
case LED1_ON_CMD:/*处理LED1 ON命令*/
printf("LED1_ON_CMD\r\n");
sprintf(buf, "Turn ON the LED1\r\n");
send(s, buf, strlen(buf));
P0_4 = 0;       /*将GPIO 0_4设置为0, 与低有效LED连接*/
break;
case LED2_ON_CMD:        /*处理LED2 ON命令*/
printf("LED2_ON_CMD\r\n");
sprintf(buf, "Turn ON the LED2\r\n");
send(s, buf, strlen(buf));
P0_5 = 0;        /* 将GPIO 0_5设置为0,与低有效LED连接*/
break;
case LED0_OFF_CMD:        /* 处理LED0 OFF命令*/
printf("LED0_OFF_CMD\r\n");
sprintf(buf, "Turn OFF the LED0\r\n");
send(s, buf, strlen(buf));
P0_3 = 1;        /*将GPIO 0_3设置为1,与低有效LED连接*/
break;
case LED1_OFF_CMD:        /* 处理LED1 OFF命令*/
printf("LED1_OFF_CMD\r\n");
sprintf(buf, "Turn OFF the LED1\r\n");
send(s, buf, strlen(buf));
P0_4 = 1;        /* 将GPIO 0_4设置为1,与低有效LED连接*/
break;
case LED2_OFF_CMD:        /* 处理LED2 OFF命令*/
printf("LED2_OFF_CMD\r\n");
sprintf(buf, "Turn OFF the LED2\r\n");
send(s, buf, strlen(buf));
P0_5 = 1;        /* 将GPIO 0_5设置为,与低有效LED连接*/
break;
case EXIT_CMD:        /*处理EXIT 命令*/
printf("EXIT command\r\n");
sprintf(buf, "EXIT command\r\n Good Bye~~\r\n Logout from W7100 TELNET");
send(s, buf, strlen(buf));
close(s);
user_state = LOGOUT;
break;
default:
break;
}
}
程序4.4proc_command()函数

4.5 willopt(), wontopt(), doopt()和dontopt()函数
willopt(), wontopt(), doopt()和dontopt()函数是用于协商Telnet选项的命令。它们需要socket s和选项作为输入参数。更多关于每个命令和选项的详细信息,请参阅表2.1和2.2。
void willopt(SOCKET s, int opt)
{
int ack;
printf("Recv: will");
if(opt <= NOPTIONS)  printf("%s\r\n", tel_options[opt]);
else  printf("%u\r\n", opt);
switch(opt){
case TN_TRANSMIT_BINARY:
case TN_ECHO:
case TN_SUPPRESS_GA:
ack = DO;     /*如果接收到‘WILL’并且它包含TN_SUPPRESS_GA选项,发送‘DO’ */
break;
default:
ack = DONT;  /* 拒绝其它未定义的命令*/
}
sendIAC(s, ack, opt);
}

void wontopt(SOCKET s, int opt)
{
printf("recv: wont");
if (opt <= NOPTIONS)  printf("%s\r\n", tel_options[opt]);
else  printf("%u\r\n", opt);
switch(opt){
case TN_TRANSMIT_BINARY:
case TN_ECHO:
case TN_SUPPRESS_GA:    /*如果接收到WONT带有TN_SUPPRESS_GA选项的命令*/
if (remote[opt] == 0){
remote[opt] = 1;     /*设置TN_SUPPRESS_GA选项*/
sendIAC(s, DONT, opt);  /* 发送带有TN_SUPPRESS_GA 选项的DONT命令*/
}
break;
}
}

void doopt(SOCKET s, int opt)
{
printf("recv: do ");
if (opt <= NOPTIONS)  printf("%s\r\n", tel_options[opt]);
else  printf("%u\r\n", opt);
switch(opt){
case TN_SUPPRESS_GA:      /*如果接收到带有TN_SUPPRESS_GA 选项的DO命令*/
sendIAC(s, WILL, opt);     /* 发送带有TN_SUPPRESS_GA选项的WILL命令*/
break;
case TN_ECHO:    /* 如果接收带有TN_ECHO选项的DO命令*/
sprintf(buf, "WELCOME TO THE W7100 TELNET SERVER!!\r\nPlease insert your ID: ");
send(s, buf, strlen(buf));
break;
default:
sendIAC(s, WONT, opt);
}
}

void dontopt(int opt)
{
printf("recv: dont ");
if (opt <= NOPTIONS) printf("%s\r\n", tel_options[opt]);
else printf("%u\r\n", opt);
switch(opt){
case TN_TRANSMIT_BINARY:
case TN_ECHO:
case TN_SUPPRESS_GA:    /*如果接收带有TN_SUPPRESS_GA 选项的DON’T命令*/
if (remote[opt] == 0) remote[opt] = 1;  /*设置TN_SUPPRESS_GA选型*/
break;
}
}
程序4.5willopt(), wontopt(), doopt() and dontopt()函数


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