linux網路socket編程用戶端端（tcp/udp）

//positve.c //對tcp和udp均適用#include #include #include #include #include #include void error(int status, int err,char *fmt, ...) { va_list ap; va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); if(err)  fprintf(stderr,":%s(%d)/n",strerror(err),err); if(status)  exit(status);}static void  set_address(const char * hname, const char *sname,    struct sockaddr_in *sap, char *protocol) { struct servent *sp; struct hostent *hp; short port; bzero(sap, sizeof(*sap)); sap->sin_family = AF_INET; if(hname != NULL) {  if(!inet_aton(hname, sap->sin_addr)) {   hp = gethostbyname(hname);   if(hp == NULL)    error(1, 0, "unkown host %s", hname);   sap->sin_addr = *(struct in_addr *)hp->h_addr;  } } else  sap->sin_addr.s_addr = htonl(INADDR_ANY); if (sp = getservbyname(sname, protocol))  sap->sin_port = sp->s_port; else if ((sap->sin_port = htons((short)atoi(sname))) == 0)           error(1,0,"unkown serivce  %s", sname);  }int client(char *hname, char *sname,  struct sockaddr_in * server , char *protocol) { int s,type; const int on = 1; if(strcmp(protocol,"tcp")==0)  type = SOCK_STREAM; else   type = SOCK_DGRAM;  if((s=socket(AF_INET, type, 0)) <= 0)  error(1, 0, "create socket failed!"); set_address(hname, sname, server, protocol); if(setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)))  error(1,errno,"setsocket option failed!"); if((type==SOCK_STREAM)    &&connect(s,(struct sockaddr *)server,sizeof(*server)))  error(1, errno, "connect error!"); return s;} //tcpclient.c#include #include #include #include #include #include #include #include void process_client(int s) {     char buff[128];     int rc,maxfd;     fd_set rset;     FD_ZERO(&rset);     while(1) {      FD_SET(s,&rset); FD_SET(0,&rset); maxfd=s+1; if(select(maxfd,&rset,NULL,NULL,NULL)==-1)  error(1,0,"select error!"); if(FD_ISSET(s,&rset)) {       rc = recv(s,buff,sizeof(buff),0);       if(rc <= 0)          break;  buff[rc]='/0';  write(1,buff,rc); } if(FD_ISSET(0,&rset)) {       if(fgets(buff,sizeof(buff),stdin)==NULL)   shutdown(s,SHUT_WR);       send(s,buff,strlen(buff),0); }     }     /*     while(fgets(buff,sizeof(buff),stdin)!=NULL) {      send(s,buff,strlen(buff),0);      rc = recv(s,buff,sizeof(buff),0);      if(rc <= 0)         break; buff[rc]='/0'; write(1,buff,rc); bzero(buff,sizeof(buff));     }     */}int main(int argc, char **argv) {    struct sockaddr_in server,temp;    char *hname, *sname;    int s, c, len;    if(argc < 2)     error(1,0,"parameters less than 2");    else if(argc == 2) {     hname = NULL; sname = argv[1];    }    else if(argc == 3) {     hname = argv[1]; sname = argv[2];    }    s = client(hname, sname, &server, "tcp");    len=sizeof(temp);    getsockname(s,(struct sockaddr *)&temp,&len);    printf("local %s:%d/n",inet_ntoa(temp.sin_addr),ntohs(temp.sin_port));        getpeername(s,(struct sockaddr *)&temp,&len);    printf("remote %s:%d/n",inet_ntoa(temp.sin_addr),ntohs(temp.sin_port));    process_client(s);    close(s);    exit(0);}//udpclient.c#include #include #include #include #include #include void process_client(int s, struct sockaddr_in *server) {     char buff[128];     int rc;      struct sockaddr_in reply;     int len;     while(fgets(buff,sizeof(buff),stdin)!=NULL){      sendto(s, buff, strlen(buff),0, (struct sockaddr *)server, sizeof(*server));      rc=recvfrom(s,buff,sizeof(buff), 0, (struct sockaddr *)&reply,&len); buff[rc]='/0';      write(1,buff,rc);     }}int main(int argc, char **argv) {    struct sockaddr_in server;    char *hname, *sname;    int s, c, len;    if(argc < 2)     error(1,0,"parameters less than 2");    else if(argc == 2) {     hname = NULL; sname = argv[1];    }    else if(argc == 3) {     hname = argv[1]; sname = argv[2];    }    s = client(hname, sname, &server , "udp");    process_client(s, &server);    close(s);    exit(0);}