libserver / libclient (softsec)

client.c

#include <netinet/ip.h>
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>

const char leng[] = "1025";

/* Sends a *null-terminated* string to the specified port.
 * Returns 0 on success, -1 on failure.
 */
int sndmsg(char msg[1024], int port)
{
  struct sockaddr_in addr;
  char dest[1032];
  strncpy(dest, msg, 1024);
  dest[1024] = '\0';
  int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
  if ( fd >= 0 )
  {
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    if ( inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) > 0 )
    {
      if ( connect(fd, (const struct sockaddr *)&addr, sizeof(struct sockaddr_in)) >= 0 )
      {
        send(fd, leng, sizeof(leng), 0);
        send(fd, dest, strlen(dest), 0);
        close(fd);
        return 0;
      }
      else
      {
        puts("\nConnection Failed ");
        return -1;
      }
    }
    else
    {
      puts("\nInvalid address/ Address not supported ");
      return -1;
    }
  }
  else
  {
    puts("\n Socket creation error ");
    return -1;
  }
}

server.c

#include <stdint.h>
#include <sys/socket.h>
#include <stdbool.h>
#include <netinet/ip.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

int server_fd;
struct sockaddr_in address;

/* Starts the server on the specified port
 * Exits on failure.
 * Returns 0 on success.
 */
int startserver(uint16_t port)
{
  server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
  if ( server_fd < 0 )
  {
    perror("socket failed");
    exit(1);
  }
  int reuseport = true;
  if ( setsockopt(server_fd, SOL_SOCKET, SO_REUSEPORT, &reuseport, sizeof(reuseport)) )
  {
    perror("setsockopt");
    exit(1);
  }
  address.sin_family = AF_INET;
  address.sin_addr.s_addr = 0;
  address.sin_port = htons(port);
  if ( bind(server_fd, (const struct sockaddr *)&address, sizeof(struct sockaddr_in)) < 0 )
  {
    perror("bind failed");
    exit(1);
  }
  int result = listen(server_fd, 3);
  if ( result < 0 )
  {
    perror("listen");
    exit(1);
  }
  return result;
}

ssize_t valread;
int new_socket;
socklen_t addrlen = sizeof(struct sockaddr_in);

/* Blocks until a message is received and write it to the buffer.
 * The message must be a null-terminated string at most 1024 characters long (null character excluded).
 * Exits on failure.
 * Returns 0 on success.
 */
int getmsg(char msg_read[1024])
{
  char buf[1024];
  memset(buf, 0, sizeof(buf));
  new_socket = accept(server_fd, (struct sockaddr*)&address, &addrlen);
  if ( new_socket < 0 )
  {
    perror("accept");
    exit(1);
  }
  valread = read(new_socket, buf, 5);
  int len = atoi(buf);
  valread = read(new_socket, buf, len);
  close(new_socket);
  strcpy(msg_read, buf);
  return 0;
}

/* Stops the server.
 * Returns 0.
 */
int stopserver()
{
  close(server_fd);
  return 0;
}