Socket网络编程略窥一二.. 网络原理课的课程设计

完全是看这篇文章学的, 貌似有中文版但是我点不进去
就不说两句了, 底层的东西, 全是细节, 非要概括的话可以引用原文第五章的小标题来描述这个过程

5.1. getaddrinfo()—Prepare to launch!
5.2. socket()—Get the File Descriptor!
5.3. bind()—What port am I on?
5.4. connect()—Hey, you!
5.5. listen()—Will somebody please call me?
5.6. accept()—”Thank you for calling port 3490.”
5.7. send() and recv()—Talk to me, baby!
5.8. sendto() and recvfrom()—Talk to me, DGRAM-style
5.9. close() and shutdown()—Get outta my face!

我的代码, 这是linux的, windows有点小不一样, 我不知道 :):
头文件..

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <stdlib.h>

#define MYPORT "2222"
#define BACKLOG 10

用Stream的:

(两个楞大的大括号…)

#include "commonheader.h"

int main() {
  char function;
  do {
    printf("choose to be server(s) or client(c)?\n");
    scanf("%c",&function);
  } while(function!='c' && function!='s');

  if(function=='s') {
    struct addrinfo hints,*localSv;
    memset(&hints,0x00,sizeof(hints));
    hints.ai_family=AF_UNSPEC;
    hints.ai_socktype=SOCK_STREAM;
    hints.ai_flags=AI_PASSIVE;
    
    int rv;
    rv=getaddrinfo(NULL,MYPORT,&hints,&localSv);
    if(rv!=0) {
      fprintf(stderr,"getaddinfo: %s\n",gai_strerror(rv));
      return 1;
    }

    int sockLs;
    struct addrinfo *p;
    for( p=localSv;p;p=p->ai_next) {
      if( (sockLs=socket(p->ai_family,p->ai_socktype,p->ai_protocol))==-1) {
	perror("server: socket");
	continue;
      }
    
      if(bind(sockLs,p->ai_addr, p->ai_addrlen)==-1) {
	shutdown(sockLs,2);
	perror("server: bind");
	continue;
      }

      break;
    }//why linked table?

    if(p==NULL) {
      perror("server: failed to bind");
      return 2;
    }

    freeaddrinfo(localSv); //all done with this structure.. so bind() did nothing to struct addrinfo! only to socket(create a socket, and the int is only its number).
    
    if (listen(sockLs,BACKLOG)==-1) {
      perror("listen");
      exit(1);
    }
	      
    struct sockaddr_storage clientSockaddr;
    int sockCon;
    printf("Listening..\n");
    socklen_t clientSockaddrSize=sizeof(clientSockaddr);
    sockCon=accept(sockLs,(struct sockaddr*)&clientSockaddr,&clientSockaddrSize);
    printf("Connected.\n");
    shutdown(sockLs,2);
    
    while(1) {
      char buff[1024];
      recv(sockCon,buff,sizeof(buff),0);
      if(strcmp(buff,"exit")==0) {
	printf("Client exited.\n");
	break;
      }
      printf("%s\n",buff);
    }

    shutdown(sockCon,2);
  }

  if(function=='c') {
    printf("Sever IP:\n");
    char svIp[16];
    scanf("%s",svIp);
        
    struct addrinfo hints,*remoteSv;
    memset(&hints,0x00,sizeof(hints));
    hints.ai_family=AF_UNSPEC;
    hints.ai_socktype=SOCK_STREAM;
    int rv=getaddrinfo(svIp,MYPORT,&hints,&remoteSv);
    if(rv!=0) {
      fprintf(stderr,"getaddinfo: %s\n",gai_strerror(rv));
      return 1;
    }
    
    int sockCl;
    struct addrinfo *p;
    for(p=remoteSv;p;p=p->ai_next) {
      if( (sockCl=socket(p->ai_family,p->ai_socktype,p->ai_protocol))==-1) {
	perror("server: socket");
	continue;
      }
      
      if(connect(sockCl,p->ai_addr,p->ai_addrlen)==-1) {
	shutdown(sockCl,2);
	printf("server: connect");
	continue;
      }

      break;
    }

    if(p==NULL) {
      perror("server:failed to setup");
      return 2;
    }

    freeaddrinfo(remoteSv);
    
    printf("connected.\n");

    while(1) {
      char buff[1024];
      scanf("%s",buff);
      send(sockCl,buff,sizeof(buff),0);
      if(strcmp(buff,"exit")==0) {
	printf("Exited.\n");
	break;
      }
    }
    shutdown(sockCl,2);
  }

  return 0;
}

用Datagram的:

#include "commonheader.h"

int main() {
  char function;
  do {
    printf("choose to be server(s) or client(c)?\n");
    scanf("%c",&function);
  } while(function!='c' && function!='s');

  if(function=='s') {
    struct addrinfo hints,*localSv;
    memset(&hints,0x00,sizeof(hints));
    hints.ai_family=AF_UNSPEC;
    hints.ai_socktype=SOCK_DGRAM;
    hints.ai_flags=AI_PASSIVE;
    
    int rv;
    rv=getaddrinfo(NULL,MYPORT,&hints,&localSv);
    if(rv!=0) {
      fprintf(stderr,"getaddinfo: %s\n",gai_strerror(rv));
      return 1;
    }

    int sockLs;
    struct addrinfo *p;
    for( p=localSv;p;p=p->ai_next) {
      if( (sockLs=socket(p->ai_family,p->ai_socktype,p->ai_protocol))==-1) {
	perror("server: socket");
	continue;
      }

      if(bind(sockLs,p->ai_addr,p->ai_addrlen)==-1) {
	shutdown(sockLs,2);
	perror("server: bind");
      }
      
      break;
    }//why linked table?

    if(p==NULL) {
      perror("server: failed to setup");
      return 2;
    }

    freeaddrinfo(localSv); //all done with this structure.. so bind() did nothing to struct addrinfo! only to socket(create a socket, and the int is only its number).

    /*
    if (listen(sockLs,BACKLOG)==-1) {
      perror("listen");
      exit(1);
      }
	      
    struct sockaddr_storage clientSockaddr;
    int sockCon;
    printf("Listening..\n");
    socklen_t clientSockaddrSize=sizeof(clientSockaddr);
    sockCon=accept(sockLs,(struct sockaddr*)&clientSockaddr,&clientSockaddrSize);
    printf("Connected.\n");
    shutdown(sockLs,2);
    */
    
    while(1) {
      char buff[1024];
      struct sockaddr from;
      socklen_t fromlen;
      recvfrom(sockLs,buff,sizeof(buff),0,
	       &from,&fromlen);
      if(strcmp(buff,"exit")==0) {
	printf("Client exited.\n");
	break;
      }
      printf("%s\n",buff);
    }

    //    shutdown(sockCon,2);
  }

  if(function=='c') {
    printf("Sever IP:\n");
    char svIp[100];
    scanf("%s",svIp);
        
    struct addrinfo hints,*remoteSv;
    memset(&hints,0x00,sizeof(hints));
    hints.ai_family=AF_UNSPEC;
    hints.ai_socktype=SOCK_DGRAM;
    int rv=getaddrinfo(svIp,MYPORT,&hints,&remoteSv);
    if(rv!=0) {
      fprintf(stderr,"getaddinfo: %s\n",gai_strerror(rv));
      return 1;
    }
    
    int sockCl;
    struct addrinfo *p;
    for(p=remoteSv;p;p=p->ai_next) {
      if( (sockCl=socket(p->ai_family,p->ai_socktype,p->ai_protocol))==-1) {
	perror("server: socket");
	continue;
      }
      
      /*
      if(connect(sockCl,p->ai_addr,p->ai_addrlen)==-1) {
	shutdown(sockCl,2);
	printf("server: connect");
	continue;
      }
      */

      break;
    }

    if(p==NULL) {
      perror("server:failed to setup");
      return 2;
    }

    //    freeaddrinfo(remoteSv);
    
    //    printf("connected.\n");

    while(1) {
      char buff[1024];
      scanf("%s",buff);
      sendto(sockCl,buff,sizeof(buff),0,
	     p->ai_addr,p->ai_addrlen);
      if(strcmp(buff,"exit")==0) {
	printf("Exited.\n");
	break;
      }
    }
    shutdown(sockCl,2);
  }

  return 0;
}