Linux系统编程之UDP网络编程模型

UDP网络编程示例

---

服务器代码示例

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>

#define IP  "127.0.0.1"
#define PORT 7788

int main(void)
{
  int sd;
  int ret;
  struct sockaddr_in address, remote;
  socklen_t len = 0;
  char buffer[1024];

  if((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
  {
    fprintf(stderr, "socket init failed. \r\n");
    return -1;
  }

  address.sin_family = AF_INET;
  address.sin_addr.s_addr = htonl(INADDR_ANY);
  address.sin_port = htons(7788);

  if(bind(sd, (struct sockaddr *)&address, sizeof(struct sockaddr_in)) < 0)
  {
    close(sd);
    fprintf(stderr, "bind failed. \r\n");
    return -2;
  }

  len = sizeof(struct sockaddr_in);
  remote.sin_family = AF_INET;
  remote.sin_addr.s_addr = inet_addr(IP);
  remote.sin_port = htons(PORT);

  while(1)
  {
    if((ret = recvfrom(sd, buffer, sizeof(buffer), 0, (struct sockaddr *)&remote, &len)) <= 0)
      break;

    if(strncmp(buffer, "quit", 4) == 0)
      break;

    if(sendto(sd, buffer, ret, 0, (struct sockaddr *)&remote, sizeof(struct sockaddr_in)) < 0)
      break;
  }

  close(sd);
  return 0;
}

客户端代码示例

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>

#define IP  "127.0.0.1"
#define PORT 7788

int main(void)
{
  int sd;
  int ret;
  struct sockaddr_in remote;
  socklen_t len = 0;
  char buffer[1024];

  if((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
  {
    fprintf(stderr, "socket init failed. \r\n");
    return -1;
  }

  len = sizeof(struct sockaddr_in);
  remote.sin_family = AF_INET;
  remote.sin_addr.s_addr = inet_addr(IP);
  remote.sin_port = htons(PORT);

  while(1)
  {
    memset(buffer, 0x00, sizeof(buffer));

    printf("Please enter :");
    scanf("%s", buffer);

    if((ret = sendto(sd, buffer, ret, 0, (struct sockaddr *)&remote, sizeof(struct sockaddr_in))) < 0)
      break;

    if(strncmp(buffer, "quit", 4) == 0)
      break;

    if((ret = recvfrom(sd, buffer, sizeof(buffer), 0, (struct sockaddr *)&remote, &len)) < 0)
      break;

    printf("Recv from %s:%d: %s \r\n", IP, PORT, buffer);
  }

  close(sd);
  return 0;
}

---

ends