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Old Mar 4th, 2008, 10:04 AM   #11
Soulstorm
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Re: Simple BSD Sockets Problem
I managed to accept everything an IRC server has to say to me. This is my code:
c Syntax (Toggle Plain Text) 
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <unistd.h>
  4. #include <errno.h>
  5. #include <string.h>
  6. #include <netdb.h>
  7. #include <sys/types.h>
  8. #include <netinet/in.h>
  9. #include <sys/socket.h>
  10.  
  11. #define PORT 6667 // the port client will be connecting to 
  12.  
  13. #define MAXDATASIZE 2000 // max number of bytes we can get at once 
  14.  
  15. int main(int argc, char *argv[])
  16. {
  17.     int sockfd, numbytes;
  18.     char buf[MAXDATASIZE];
  19.     struct hostent *he;
  20.     struct sockaddr_in their_addr; // connector's address information
  21.  
  22.     he = gethostbyname("efnet.teleglobe.net");
  23.     sockfd = socket(PF_INET, SOCK_STREAM, 0);
  24.     if (sockfd < 0) {
  25. 		printf("error creating the socket\n");
  26.     }
  27.     their_addr.sin_family       = AF_INET;
  28.     their_addr.sin_port         = htons(PORT);
  29.     their_addr.sin_addr         = *((struct in_addr *)he->h_addr);
  30.     memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);
  31.  
  32.  
  33.     if (connect(sockfd, (struct sockaddr *)&their_addr,
  34. 				sizeof their_addr) == -1) {
  35. 		perror("connect\n");
  36. 		exit(1);
  37.     } 
  38. 	else {
  39. 		printf("You got the connection to the server!\n");
  40.  
  41. 		fprintf(stderr,"After send, entering recv loop\n");
  42. 		numbytes = 0;
  43. 		do {
  44. 			numbytes = 0;
  45. 			memset(buf, 0, sizeof(buf));
  46. 			//fprintf(stderr,"In recv loop\n");
  47. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  48. 			buf[numbytes] = '\0';
  49. 			printf("Received: %s",buf);
  50. 		} while (numbytes != 0);
  51.  
  52. 		char command[] = "ping\r\n";
  53.  
  54. 		send(sockfd, command, sizeof(command), 0);
  55.  
  56. 		do {
  57. 			numbytes = 0;
  58. 			memset(buf, 0, sizeof(buf));
  59. 			//fprintf(stderr,"In recv loop\n");
  60. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  61. 			buf[numbytes] = '\0';
  62. 			printf("Received: %s",buf);
  63. 		} while (numbytes !=0);
  64.  
  65.  
  66.  
  67. 		fflush(stdout);
  68. 		close(sockfd);
  69. 	}
  70. 	return 0;
  71. }

And this is What I get:
(Toggle Plain Text) 
You got the connection to the server!
After send, entering recv loop
Received: NOTICE AUTH :*** Processing connection to efnet.teleglobe.net
Received: NOTICE AUTH :*** Looking up your hostname...
NOTICE AUTH :*** Checking Ident
NOTICE AUTH :*** Found your hostname
Received: NOTICE AUTH :*** No Ident response
Received: ERROR :Closing Link: 127.0.0.1 (Connection timed out)
Received: Received:

The error about "no ident response" comes up after waiting a few seconds. I am behind a router, but I have port forwarded the port 113 (which is used for ident) but with no effect whatsoever.
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Old Mar 4th, 2008, 12:27 PM   #12
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Re: Simple BSD Sockets Problem
Usually that happens when you haven't sent the correct message, you haven't properly terminated the message, or you haven't sent a message when it was expecting one. My gut feeling is with the latter. During the time it's waiting, it could be waiting for you to send a valid reply or acknowledgement. I have no experience with interfacing to an IRC server, so I can't suggest anything specific.

Edit: I'm fairly confident with my assumption. NOTICE AUTH :*** No Ident response. It seems as though it was waiting for a response. Presumably, imformation about your identity. But you don't appear to send it anything. Consequently, it waits a few seconds, and then assumes you timed out and closes the connection. That is my assumption.
Last edited by Sane; Mar 4th, 2008 at 12:38 PM.
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Old Mar 6th, 2008, 5:34 AM   #13
Soulstorm
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Re: Simple BSD Sockets Problem
Quote:
Originally Posted by Sane View Post
Usually that happens when you haven't sent the correct message, you haven't properly terminated the message, or you haven't sent a message when it was expecting one. My gut feeling is with the latter. During the time it's waiting, it could be waiting for you to send a valid reply or acknowledgement. I have no experience with interfacing to an IRC server, so I can't suggest anything specific.

Edit: I'm fairly confident with my assumption. NOTICE AUTH ** No Ident response. It seems as though it was waiting for a response. Presumably, imformation about your identity. But you don't appear to send it anything. Consequently, it waits a few seconds, and then assumes you timed out and closes the connection. That is my assumption.
You were right. It waited for me to give 2 commands, the NICK and USER commands. I tried connecting to efnet.teleglobe.net using telnet (on OS X terminal, which is the equivalent of the dos command prompt) and then I entered the NICK and USER commands.

(Toggle Plain Text) 
telnet efnet.teleglobe.net 6667
NICK NICK MyWayCoolBotNick\r\n
USER ObjcBot 8 * :The Objective-C Bot\r\n

I manages to connect and receive information about the server.

However, I did that using the terminal. I don't know how can I send that using C. The only thing I manage to do is to open a telnet communication with the server with the connect() command. How can I send the other 2 commands? With the send() command? That's what I am trying in the code below.

c Syntax (Toggle Plain Text) 
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <unistd.h>
  4. #include <errno.h>
  5. #include <string.h>
  6. #include <netdb.h>
  7. #include <sys/types.h>
  8. #include <netinet/in.h>
  9. #include <sys/socket.h>
  10.  
  11. #define PORT 6667 // the port client will be connecting to 
  12.  
  13. #define MAXDATASIZE 2000 // max number of bytes we can get at once 
  14.  
  15. int main(int argc, char *argv[])
  16. {
  17. 	int sockfd, numbytes;
  18.     char buf[MAXDATASIZE];
  19.     struct hostent *he;
  20.     struct sockaddr_in their_addr; // connector's address information
  21.  
  22.     he = gethostbyname("efnet.teleglobe.net");
  23.     sockfd = socket(PF_INET, SOCK_STREAM, 0);
  24.     if (sockfd < 0) {
  25. 		printf("error creating the socket\n");
  26.     }
  27.     their_addr.sin_family       = AF_INET;
  28.     their_addr.sin_port         = htons(PORT);
  29.     their_addr.sin_addr         = *((struct in_addr *)he->h_addr);
  30.     memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);
  31.  
  32.  
  33.     if (connect(sockfd, (struct sockaddr *)&their_addr,
  34. 				sizeof their_addr) == -1) {
  35. 		perror("connect\n");
  36. 		exit(1);
  37.     } 
  38. 	else {
  39. 		printf("You got the connection to the server!\n");
  40.  
  41. 		fprintf(stderr,"After send, entering recv loop\n");
  42. 		numbytes = 0;
  43. 		do {
  44. 			numbytes = 0;
  45. 			memset(buf, 0, sizeof(buf));
  46. 			//fprintf(stderr,"In recv loop\n");
  47. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  48. 			buf[numbytes] = '\0';
  49. 			printf("Received: %s",buf);
  50. 		} while (numbytes != 0);
  51.  
  52. 		//char command[] = "PING\r\n";
  53. 		char nickCommand[] = "NICK MyWayCoolBotNick\r\n";
  54. 		char userCommand[] = "USER ObjcBot 8 * :The Objective-C Bot\r\n";
  55. 		//system("telnet efnet.teleglobe.net 6667");
  56.  
  57. 		//send(sockfd, command, sizeof(command), 0);
  58. 		send(sockfd, nickCommand, sizeof(nickCommand), 0);
  59. 		send(sockfd, userCommand, sizeof(userCommand), 0);
  60.  
  61. 		printf("exited first loop!!!\n");
  62. 		do {
  63.  
  64. 			numbytes = 0;
  65. 			memset(buf, 0, sizeof(buf));
  66. 			//fprintf(stderr,"In recv loop\n");
  67. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  68. 			buf[numbytes] = '\0';
  69. 			printf("Received: %s",buf);
  70. 		} while (numbytes !=0);
  71.  
  72.  
  73.  
  74. 		fflush(stdout);
  75. 		close(sockfd);
  76. 	}
  77. 	return 0;
  78. }

But the problem is that it is as if those last 2 commands were never sent. Any ideas?
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Old Mar 7th, 2008, 12:45 AM   #14
Game_Ender
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Re: Simple BSD Sockets Problem
All telnet does is give you a direct TCP connection to the given server on the given port. You can then type out which characters you want to send and hit enter. It then reads back whatever it gets sent and writes it to screen.

What you really should do is write a both a client and a sever TCP program and run them together. Then you will get a firmer grasp of how to use send and recv properly. Also you aren't checking the returns of send, you should always check the return value.
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Old Mar 7th, 2008, 2:54 AM   #15
Soulstorm
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Re: Simple BSD Sockets Problem
OK. I will write this dumb server.

However, I got it to work. Seems that if I give the NICK and USER command together with one send(), they will work. Otherwise, they won't. However, the strange thing is that in both cases, the return value of the send() command is 0!

I really can't understand this. I will try and write the dumb server to see what will happen.

c Syntax (Toggle Plain Text) 
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <unistd.h>
  4. #include <errno.h>
  5. #include <string.h>
  6. #include <netdb.h>
  7. #include <sys/types.h>
  8. #include <netinet/in.h>
  9. #include <sys/socket.h>
  10.  
  11. #define PORT 6667 // the port client will be connecting to 
  12.  
  13. #define MAXDATASIZE 2000 // max number of bytes we can get at once 
  14. char nickCommand[] = "NICK MyWayCoolBotNick\r\n";
  15. char userCommand[] = "USER ObjcBot 8 * :The Objective-C Bot\r\n";
  16.  
  17. char allCommands[] = "NICK MyWayCoolBotNick\r\nUSER ObjcBot 8 * :The Objective-C Bot\r\n";
  18.  
  19. int main(int argc, char *argv[])
  20. {
  21. 	int sockfd, numbytes;
  22.     char buf[MAXDATASIZE];
  23.     struct hostent *he;
  24.     struct sockaddr_in their_addr; // connector's address information
  25.  
  26.     he = gethostbyname("efnet.teleglobe.net");
  27.     sockfd = socket(PF_INET, SOCK_STREAM, 0);
  28.     if (sockfd < 0) {
  29. 		printf("error creating the socket\n");
  30.     }
  31.     their_addr.sin_family       = AF_INET;
  32.     their_addr.sin_port         = htons(PORT);
  33.     their_addr.sin_addr         = *((struct in_addr *)he->h_addr);
  34.     memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);
  35.  
  36.  
  37.     if (connect(sockfd, (struct sockaddr *)&their_addr,
  38. 				sizeof their_addr) == -1) {
  39. 		perror("connect\n");
  40. 		exit(1);
  41.     }
  42. 	else {
  43. 		//send(sockfd, nickCommand, sizeof(nickCommand), 0);
  44.  
  45. 		int bytesSent = 0;
  46. 		if ( bytesSent = send(sockfd, userCommand, sizeof(userCommand), 0) <= 0 )
  47. 			printf("could not send NICK message to the server\n");
  48. 		else
  49. 			printf("bytes sent: %i\n", bytesSent);
  50.  
  51. 		if ( send(sockfd, nickCommand, sizeof(nickCommand), 0) <= 0 )
  52. 			printf("could not send USER message to the server\n");
  53. 		else
  54. 			printf("bytes sent: %i\n", bytesSent);
  55.  
  56.  
  57. 		/*if (bytesSent = send(sockfd, allCommands, sizeof(allCommands), 0) <=0 ) {
  58. 			perror("send");
  59. 		}
  60. 		else
  61. 			printf("bytes sent: %i\n", bytesSent);
  62. 		printf("You got the connection to the server!\n");
  63. 		*/
  64. 		fprintf(stderr,"After send, entering recv loop\n");
  65. 		numbytes = 0;
  66.  
  67.  
  68. 		do {
  69. 			numbytes = 0;
  70. 			memset(buf, 0, sizeof(buf));
  71. 			//fprintf(stderr,"In recv loop\n");
  72. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  73. 			buf[numbytes] = '\0';
  74. 			printf("Received: %s",buf);
  75. 		} while (numbytes != 0);
  76.  
  77. 		//char command[] = "PING\r\n";
  78.  
  79. 		//system("telnet efnet.teleglobe.net 6667");
  80.  
  81. 		//send(sockfd, command, sizeof(command), 0);
  82.  
  83. 		printf("exited first loop!!!\n");
  84. 		do {
  85.  
  86. 			numbytes = 0;
  87. 			memset(buf, 0, sizeof(buf));
  88. 			//fprintf(stderr,"In recv loop\n");
  89. 			numbytes=recv(sockfd, buf, sizeof(buf)-1, 0); //-1 b/c you will null terminate
  90. 			buf[numbytes] = '\0';
  91. 			printf("Received: %s",buf);
  92. 		} while (numbytes !=0);
  93.  
  94.  
  95.  
  96. 		fflush(stdout);
  97. 		close(sockfd);
  98. 	}
  99. 	return 0;
  100. }
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Old Mar 7th, 2008, 3:16 PM   #16
The Dark
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Re: Simple BSD Sockets Problem
Your separate commands send the USER command then the NICK command, but your all in one sends NICK then USER. I don't know if that would cause the problem, but it would be worth checking out.

Also I would be tempted to use sizeof(userCommand) - 1 as the length to send, otherwise you are sending an extra zero byte which might be confusing the other end.
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Old Mar 7th, 2008, 5:02 PM   #17
Soulstorm
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Re: Simple BSD Sockets Problem
You got me. The last character of the commands was the problem. I deleted the last character, and everything else worked fine. Thanks a lot.
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