protocol: 特殊协议, 一般给0
准备通信地址:
struct sockaddr{
//主要用于函数的形参类型, 很少定义结构体变量使用, 叫做通用的通信地址类型//$man bind
sa_family_t
sa_family;
char
sa_data[
14];
}
struct sockaddr_un{
//准备本地通信的通信地址 //$man un.h
sa_family_t
sun_family;
//协议族,就是socket()的domain的AF_LOCAL
char
sun_path[];
//文件的路径
}
struct sockaddr_in{
//准备网络通信的通信地址 //$man in.h
sa_family_t sin_family;
//协议族, 就是socket()的domain的AF_INET
in_port_t
sin_port;
//端口号
struct in_addr sin_addr;
//IP地址
}
struct in_addr{
in_addr_t s_addr;
//整数类型的IP地址
}
bind():
//把通信地址和socket文件描述符绑定，用在服务器端，成功返回0,失败返回-1设errno
int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
sockfd: socket文件的fd(returned by socket())
addr: 需要强制类型转换成socketaddr_un或soketaddr_in, 参见上
addrlen: 通信地址的大小, 使用sizeof();
connect():
//初始化一个socket的连接，用在客户端，成功返回0,失败返回-1设errno
int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
sockfd: socket文件的fd(returned by socket())
addr: 需要强制类型转换成socketaddr_un或soketaddr_in, 参见上
addrlen: 通信地址的大小, 使用sizeof();
例子
//xxx.socket/1vs1 , server
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<sys/un.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
//1. create socket
int sockfd=socket(AF_LOCAL,SOCK_DGRAM,
0);
if(
-1==sockfd)
perror(
"socket"),
exit(
-1);
printf(
"create socket successfully\n");
//2. prepare communication addr
struct sockaddr_un addr;
addr.sun_family=AF_LOCAL;
strcpy(addr.sun_path,
"a.sock");
//会自动创建a.sock文件
//3. bind socket and addr
int res=bind(sockfd,(
struct sockaddr*)&addr,
sizeof(addr));
//客户端是connect()
if(
-1==res)
perror(
"bind"),
exit(
-1);
printf(
"bind successfully\n");
//4. communicate
char buf[
100]={
0};
res=read(sockfd,&buf,
sizeof(buf));
//客户端是write()
if(
-1==res)
perror(
"read"),
exit(
-1);
printf(
"data sent by client:%s,size is %d\n",buf,
sizeof(buf));
//5. close socket
res=close(sockfd);
if(
-1==res)
perror(
"close"),
exit(
-1);
printf(
"close successfully\n");
return 0;
}
//IP/1vs1,server
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
//1. create socket
int sockfd=socket(AF_INET,SOCK_DGRAM,
0);
if(
-1==sockfd)
perror(
"socket"),
exit(
-1);
printf(
"create socket successfully\n");
//2. prepare communication addr
struct sockaddr_in addr;
addr.sin_family=AF_INET;
addr.sin_port=htons(
8888);
//转化端口号为网络字节序
//1~1024被系统占用,这里随便给个8888 addr.sin_addr.s_addr=inet_addr("176.43.1.34");
//转化字符串IP为整数IP
//客户端也写这个服务器的地址
//3. bind socket and addr
int res=bind(sockfd,(
struct sockaddr*)&addr,
sizeof(addr));
//客户端是connect()
if(
-1==res)
perror(
"bind"),
exit(
-1);
printf(
"bind successfully\n");
//4. communicate
char buf[
100]={
0};
res=read(sockfd,&buf,
sizeof(buf));
//客户端是write()
if(
-1==res)
perror(
"read"),
exit(
-1);
printf(
"data sent by client:%s,size is %d\n",buf,
sizeof(buf));
//5. close socket
res=close(sockfd);
if(
-1==res)
perror(
"close"),
exit(
-1);
printf(
"close successfully\n");
return 0;
}
