UDP编程基础

 
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/uio.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define MAX_BUF_LEN (1500)
#define ACK_STR "udp ack ok"
void usage(void) {
    printf("*********************************\n");
    printf("./server 本端ip 本端端口\n");
    printf("*********************************\n");
}
int main(int argc, char *argv[]) {
    int sockfd;
    int ret;
    ssize_t len = 0;
    struct sockaddr_in local;
    struct sockaddr_in peer;
    socklen_t addrlen = sizeof(peer);
    char recv_buf[MAX_BUF_LEN] = {0};
if (argc != 3) {
    usage();
    return -1;
}
char *ip = argv[1];
unsigned short port = atoi(argv[2]);
printf("ip:port->%s:%u\n", argv[1], port);
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd == -1) {
    perror("socker error");
    return -1;
}
memset(&local, 0, sizeof(local));
local.sin_family = AF_INET;
local.sin_addr.s_addr = inet_addr(ip);
local.sin_port = htons(port);
ret = bind(sockfd, (struct sockaddr *)&local, sizeof(local));
if (ret == -1) {
    close(sockfd);
    perror("bind error");
    return -1;
}
while(1) {
    memset(recv_buf, 0, MAX_BUF_LEN);
    ret = recvfrom(sockfd, recv_buf, MAX_BUF_LEN, 0,
(struct sockaddr *)&peer, &addrlen);
    printf("recvfrom peer len:%d, peer ip:port->%s:%d\n",
addrlen,
inet_ntoa(peer.sin_addr),
ntohs(peer.sin_port));
    printf("recvfrom len:%d, %s\n", ret, recv_buf);
    ret = sendto(sockfd, ACK_STR, strlen(ACK_STR), 0,
(struct sockaddr *)&peer, sizeof(peer));
    printf("sendto len:%d, %s\n", ret, ACK_STR);
}
close(sockfd);
return 0;
}

 
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <bits/socket.h>
#include <sys/uio.h>
#define MAX_BUF_LEN (1500)
#define REQUEST_STR "udp pack"
void usage(void) {
    printf("*********************************\n");
    printf("./client 对端ip 对端端口\n");
    printf("*********************************\n");
}
int main(int argc, char *argv[]) {
    int sockfd;
    int ret;
    struct sockaddr_in local;
    struct sockaddr_in peer;
    socklen_t addrlen = sizeof(peer);
    char recv_buf[MAX_BUF_LEN] = {0};
if (argc != 3) {
    usage();
    return -1;
}
char *ip = argv[1];
unsigned short port = atoi(argv[2]);
printf("ip:port->%s:%u\n", argv[1], port);
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd == -1) {
    perror("socker error");
    return -1;
}
memset(&peer, 0, sizeof(peer));
peer.sin_family = AF_INET;
peer.sin_addr.s_addr = inet_addr(ip);
peer.sin_port = htons(port);
while(1) {
    ret = sendto(sockfd, REQUEST_STR, strlen(REQUEST_STR), 0,
(struct sockaddr *)&peer, sizeof(peer));
    printf("sendto len:%d, %s\n", ret, REQUEST_STR);
    memset(recv_buf, 0, MAX_BUF_LEN);
    ret = recvfrom(sockfd, recv_buf, MAX_BUF_LEN, 0,
(struct sockaddr *)&peer, &addrlen);
    printf("recvfrom peer len:%d, peer ip:port->%s:%d\n",
addrlen,
inet_ntoa(peer.sin_addr),
ntohs(peer.sin_port));
    printf("recvfrom len:%d, %s\n", ret, recv_buf);
    sleep(1);
}
close(sockfd);
return 0;
}