linux下echo与time服务的程序实现

一、针对ECHO服务的TCP客户软件的实现

1.网络拓扑结构：

2.源码：

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <unistd.h>
  4 #include <string.h>
  5 #include <stdarg.h>
  6 #include <sys/types.h>
  7 #include <sys/socket.h>
  8 #include <netinet/in.h>
  9 #include <arpa/inet.h>
 10 #include <netdb.h>
 11 #include <errno.h>
 12 
 13 #define LINELEN 128
 14 extern int errno;
 15 
 16 int TCPecho(const char *host, const char *service);
 17 int errexit(const char *format,...);
 18 int connectsock(const char *host, const char *service, const char *transport );
 19 int connectTCP(const char *host, const char *service);
 20 
 21 int main(int argc, char *argv[]){
 22     char *host= "localhost";
 23     char *service= "echo";
 24     switch(argc){
 25 case 1:
 26     host = "localhost";
 27     break;
 28 case 3:
 29     service = argv[2];
 30 case 2:
 31     host=argv[1];
 32     break;
 33 default:
 34     fprintf(stderr,"usage:TCPecho[host[port]]
");
 35     exit(1);
 36     }
 37     TCPecho(host,service);
 38     exit(0);
 39 }
 40 int TCPecho(const char *host,const char *service){
 41     char buf[LINELEN+1];
 42     int s,n;
 43     int outchars, inchars;
 44     s=connectTCP(host, service);
 45     while(fgets(buf,sizeof(buf),stdin)){
 46         buf[LINELEN]='';
 47         outchars=strlen(buf);
 48         (void)write(s,buf,outchars);
 49         for(inchars=0;inchars<outchars;inchars+=n){
 50             n=read(s,&buf[inchars],outchars-inchars);
 51             if(n<0)
 52                     errexit("socker read failed: %s
",strerror(errno));
 53         }
 54         fputs(buf,stdout);
 55     }
 56 }
 57 int errexit(const char *format,...){
 58     va_list arg;
 59     va_start(arg, format);
 60     vfprintf(stderr,format,arg);
 61     va_end(arg);
 62     exit(1);
 63 }
 64 int connectsock(const char *host, const char *service, const char *transport )
 65 /*
 66  * Arguments:
 67  *      host      - name of host to which connection is desired
 68  *      service   - service associated with the desired port
 69  *      transport - name of transport protocol to use ("tcp" or "udp")
 70  */
 71 {
 72     struct hostent  *phe;   /* pointer to host information entry    */
 73     struct servent  *pse;   /* pointer to service information entry */
 74     struct protoent *ppe;   /* pointer to protocol information entry*/
 75     struct sockaddr_in sin; /* an Internet endpoint address     */
 76     int s, type;    /* socket descriptor and socket type    */
 77 
 78 
 79     memset(&sin, 0, sizeof(sin));
 80     sin.sin_family = AF_INET;
 81 
 82     /* Map service name to port number */
 83     if ( pse = getservbyname(service, transport) )
 84         sin.sin_port = pse->s_port;
 85     else if ((sin.sin_port=htons((unsigned short)atoi(service))) == 0)
 86         errexit("can't get "%s" service entry
", service);
 87 
 88     /* Map host name to IP address, allowing for dotted decimal */
 89     if ( phe = gethostbyname(host) )
 90         memcpy(&sin.sin_addr, phe->h_addr, phe->h_length);
 91     else if ( (sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE )
 92         errexit("can't get "%s" host entry
", host);
 93 
 94     /* Map transport protocol name to protocol number */
 95     if ( (ppe = getprotobyname(transport)) == 0)
 96         errexit("can't get "%s" protocol entry
", transport);
 97 
 98     /* Use protocol to choose a socket type */
 99     if (strcmp(transport, "udp") == 0)
100         type = SOCK_DGRAM;
101     else
102         type = SOCK_STREAM;
103 
104     /* Allocate a socket */
105     s = socket(PF_INET, type, ppe->p_proto);
106     if (s < 0)
107         errexit("can't create socket: %s
", strerror(errno));
108 
109     /* Connect the socket */
110     if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
111         errexit("can't connect to %s.%s: %s
", host, service,
112             strerror(errno));
113     return s;
114 }
115 int connectTCP(const char *host, const char *service){
116     return connectsock(host,service,"tcp");
117 }

二、针对echo服务的并发的面向连接的服务器软件的实现

1.网络拓扑结构：

2.源码：

  1 #define _USE_BSD
  2 #include <stdio.h>
  3 #include <stdlib.h>
  4 #include <unistd.h>
  5 #include <string.h>
  6 #include <stdarg.h>
  7 #include <sys/types.h>
  8 #include <sys/socket.h>
  9 #include <netinet/in.h>
 10 #include <arpa/inet.h>
 11 #include <netdb.h>
 12 #include <signal.h>
 13 #include <errno.h>
 14 
 15 #define QLEN 32
 16 #define BUFSIZE 4096
 17 extern int errno;
 18 unsigned short portbase = 0;
 19 
 20 void reaper(int);
 21 int TCPechod(int fd);
 22 int errexit(const char *format,...);
 23 int passivesock(const char *service, const char *transport, int qlen);
 24 int passiveTCP(const char *service,int qlen);
 25 
 26 int main(int argc, char *argv[]){
 27     char *service= "echo";
 28     struct sockaddr_in fsin;
 29     unsigned int alen;
 30     int msock,ssock;
 31     switch(argc){
 32 case 1:
 33     break;
 34 case 2:
 35     service=argv[1];
 36     break;
 37 default:
 38     errexit("usage: TCPechod [port]
");
 39     }
 40 
 41     msock=passiveTCP(service,QLEN);
 42     (void)signal(SIGCHLD,(__sighandler_t)QLEN);
 43 
 44     while(1){
 45         alen=sizeof(fsin);
 46         ssock=accept(msock,(struct sockaddr *)&fsin,&alen);
 47         if(ssock<0){
 48             if(errno==EINTR)    continue;
 49             errexit("accept: %s
",strerror(errno));
 50         }
 51         switch(fork()){
 52     case 0:
 53         (void)close(msock);
 54         exit(TCPechod(ssock));
 55     default:
 56         (void)close(ssock);
 57         break;
 58     case -1:
 59         errexit("fork: %s
",strerror(errno));
 60         }
 61     }
 62 }
 63 
 64 void reaper(int sig){
 65     int status;
 66     while(wait3(&status,WNOHANG,(struct rusage *)0)>=0) ;
 67 }
 68 int TCPechod(int fd){
 69     char buf[BUFSIZ];
 70     int cc;
 71 
 72     while(cc=read(fd,buf,sizeof(buf))){
 73         if(cc<0)
 74             errexit("echo read: %s
",strerror(errno));
 75         if(write(fd,buf,cc)<0)
 76             errexit("echo write: %s
",strerror(errno));
 77     }
 78     return 0;
 79 }
 80 int errexit(const char *format,...){
 81     va_list arg;
 82     va_start(arg, format);
 83     vfprintf(stderr,format,arg);
 84     va_end(arg);
 85     exit(1);
 86 }
 87 int passivesock(const char *service, const char *transport, int qlen)
 88 /*
 89  * Arguments:
 90  *      service   - service associated with the desired port
 91  *      transport - transport protocol to use ("tcp" or "udp")
 92  *      qlen      - maximum server request queue length
 93  */
 94 {
 95 
 96     struct servent*pse;/* pointer to service information entry*/
 97     struct protoent *ppe;/* pointer to protocol information entry*/
 98     struct sockaddr_in sin;/* an Internet endpoint address*/
 99     int s, type;/* socket descriptor and socket type*/
100 
101     memset(&sin, 0, sizeof(sin));
102     sin.sin_family = AF_INET;
103     sin.sin_addr.s_addr = INADDR_ANY;
104 
105         /* Map service name to port number */
106     if ( pse = getservbyname(service, transport) )
107     sin.sin_port = htons(ntohs((unsigned short)pse->s_port)+ portbase);
108     else
109               if ((sin.sin_port=htons((unsigned short)atoi(service)+portbase)) == 0)
110     errexit("can't create passive service %d 
",sin.sin_port);
111 
112         /* Map protocol name to protocol number */
113     if ( (ppe = getprotobyname(transport)) == 0)
114     errexit("can't get "%s" protocol entry
", transport);
115 
116         /* Use protocol to choose a socket type */
117     if (strcmp(transport, "udp") == 0)
118     type = SOCK_DGRAM;
119     else
120     type = SOCK_STREAM;
121 
122         /* Allocate a socket */
123     s = socket(PF_INET, type, ppe->p_proto);
124     if (s < 0)
125     errexit("can't create socket: %s
", strerror(errno));
126 
127         /* Bind the socket */
128     if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
129     errexit("can't bind to %s port: %s
", service,
130     strerror(errno));
131     if (type == SOCK_STREAM && listen(s, qlen) < 0)
132     errexit("can't listen on %s port: %s
", service,
133     strerror(errno));
134     return s;
135 }
136 int passiveTCP(const char *service,int qlen){
137     return passivesock(service,"tcp",qlen);
138 }

三、针对TIME服务的UDP客户软件的实现

1.网络拓扑结构：

2.源码：

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <unistd.h>
  4 #include <string.h>
  5 #include <stdarg.h>
  6 #include <sys/types.h>
  7 #include <sys/socket.h>
  8 #include <netinet/in.h>
  9 #include <arpa/inet.h>
 10 #include <netdb.h>
 11 #include <time.h>
 12 #include <errno.h>
 13 
 14 #define BUFSIZE 64
 15 #define UNIXEPOCH 2208988800UL
 16 #define MSG "what time is it?
"
 17 extern int errno;
 18 
 19 int errexit(const char *format,...);
 20 int connectsock(const char *host, const char *service, const char *transport );
 21 int connectUDP(const char *host, const char *service);
 22 
 23 int main(int argc, char *argv[]){
 24     char *host= "localhost";
 25     char *service= "time";
 26     time_t now;
 27     int s,n;
 28 
 29     switch(argc){
 30 case 1:
 31     host = "localhost";
 32     break;
 33 case 3:
 34     service = argv[2];
 35 case 2:
 36     host=argv[1];
 37     break;
 38 default:
 39     fprintf(stderr,"usage: UDPtime[host[port]]
");
 40     exit(1);
 41     }
 42 
 43     s=connectUDP(host,service);
 44     (void)write(s,MSG,strlen(MSG));
 45 
 46     n=read(s,(char *)&now,sizeof(now));
 47     if(n<0)     errexit("read failed: %s
",strerror(errno));
 48     now=ntohl((unsigned long)now);
 49     now-=UNIXEPOCH;
 50     printf("%s",ctime(&now));
 51     exit(0);
 52 }
 53 int errexit(const char *format,...){
 54     va_list arg;
 55     va_start(arg, format);
 56     vfprintf(stderr,format,arg);
 57     va_end(arg);
 58     exit(1);
 59 }
 60 int connectsock(const char *host, const char *service, const char *transport )
 61 /*
 62  * Arguments:
 63  *      host      - name of host to which connection is desired
 64  *      service   - service associated with the desired port
 65  *      transport - name of transport protocol to use ("tcp" or "udp")
 66  */
 67 {
 68     struct hostent  *phe;   /* pointer to host information entry    */
 69     struct servent  *pse;   /* pointer to service information entry */
 70     struct protoent *ppe;   /* pointer to protocol information entry*/
 71     struct sockaddr_in sin; /* an Internet endpoint address     */
 72     int s, type;    /* socket descriptor and socket type    */
 73 
 74 
 75     memset(&sin, 0, sizeof(sin));
 76     sin.sin_family = AF_INET;
 77 
 78     /* Map service name to port number */
 79     if ( pse = getservbyname(service, transport) )
 80         sin.sin_port = pse->s_port;
 81     else if ((sin.sin_port=htons((unsigned short)atoi(service))) == 0)
 82         errexit("can't get "%s" service entry
", service);
 83 
 84     /* Map host name to IP address, allowing for dotted decimal */
 85     if ( phe = gethostbyname(host) )
 86         memcpy(&sin.sin_addr, phe->h_addr, phe->h_length);
 87     else if ( (sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE )
 88         errexit("can't get "%s" host entry
", host);
 89 
 90     /* Map transport protocol name to protocol number */
 91     if ( (ppe = getprotobyname(transport)) == 0)
 92         errexit("can't get "%s" protocol entry
", transport);
 93 
 94     /* Use protocol to choose a socket type */
 95     if (strcmp(transport, "udp") == 0)
 96         type = SOCK_DGRAM;
 97     else
 98         type = SOCK_STREAM;
 99 
100     /* Allocate a socket */
101     s = socket(PF_INET, type, ppe->p_proto);
102     if (s < 0)
103         errexit("can't create socket: %s
", strerror(errno));
104 
105     /* Connect the socket */
106     if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
107         errexit("can't connect to %s.%s: %s
", host, service,
108             strerror(errno));
109     return s;
110 }
111 int connectUDP(const char *host, const char *service){
112     return connectsock(host,service,"udp");
113 }

四、针对TIME服务的UDP服务器端软件的实现

1.网络拓扑结构：

2.源码：

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <unistd.h>
  4 #include <string.h>
  5 #include <stdarg.h>
  6 #include <sys/types.h>
  7 #include <sys/socket.h>
  8 #include <netinet/in.h>
  9 #include <arpa/inet.h>
 10 #include <netdb.h>
 11 #include <errno.h>
 12 
 13 #define UNIXEPOCH 2208988800UL
 14 
 15 extern int errno;
 16 unsigned short portbase = 0;
 17 
 18 int errexit(const char *format,...);
 19 int passivesock(const char *service, const char *transport, int qlen);
 20 int passiveUDP(const char *service);
 21 
 22 int main(int argc, char *argv[]){
 23     char *service= "time";
 24     struct sockaddr_in fsin;
 25     char buf[1];
 26     int sock;
 27     time_t now;
 28     unsigned int alen;
 29 
 30     switch(argc){
 31 case 1:
 32     break;
 33 case 2:
 34     service=argv[1];
 35     break;
 36 default:
 37     errexit("usage: UDPtimed [port]
");
 38     }
 39 
 40     sock=passiveUDP(service);
 41 
 42     while(1){
 43         alen=sizeof(fsin);
 44         if(recvfrom(sock,buf,sizeof(buf),0,(struct sockaddr *)&fsin,&alen)<0)
 45             errexit("recvfrom: %s
",strerror(errno));
 46         (void)time(&now);
 47         now=htonl((unsigned long)(now+UNIXEPOCH));
 48         (void)sendto(sock,(char*)&now,sizeof(now),0,(struct sockaddr *)&fsin,sizeof(fsin));
 49     }
 50 }
 51 
 52 int errexit(const char *format,...){
 53     va_list arg;
 54     va_start(arg, format);
 55     vfprintf(stderr,format,arg);
 56     va_end(arg);
 57     exit(1);
 58 }
 59 int passivesock(const char *service, const char *transport, int qlen)
 60 /*
 61  * Arguments:
 62  *      service   - service associated with the desired port
 63  *      transport - transport protocol to use ("tcp" or "udp")
 64  *      qlen      - maximum server request queue length
 65  */
 66 {
 67 
 68     struct servent*pse;/* pointer to service information entry*/
 69     struct protoent *ppe;/* pointer to protocol information entry*/
 70     struct sockaddr_in sin;/* an Internet endpoint address*/
 71     int s, type;/* socket descriptor and socket type*/
 72 
 73     memset(&sin, 0, sizeof(sin));
 74     sin.sin_family = AF_INET;
 75     sin.sin_addr.s_addr = INADDR_ANY;
 76 
 77         /* Map service name to port number */
 78     if ( pse = getservbyname(service, transport) )
 79     sin.sin_port = htons(ntohs((unsigned short)pse->s_port)+ portbase);
 80     else
 81               if ((sin.sin_port=htons((unsigned short)atoi(service)+portbase)) == 0)
 82     errexit("can't create passive service %d 
",sin.sin_port);
 83 
 84         /* Map protocol name to protocol number */
 85     if ( (ppe = getprotobyname(transport)) == 0)
 86     errexit("can't get "%s" protocol entry
", transport);
 87 
 88         /* Use protocol to choose a socket type */
 89     if (strcmp(transport, "udp") == 0)
 90     type = SOCK_DGRAM;
 91     else
 92     type = SOCK_STREAM;
 93 
 94         /* Allocate a socket */
 95     s = socket(PF_INET, type, ppe->p_proto);
 96     if (s < 0)
 97     errexit("can't create socket: %s
", strerror(errno));
 98 
 99         /* Bind the socket */
100     if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
101     errexit("can't bind to %s port: %s
", service,
102     strerror(errno));
103     if (type == SOCK_STREAM && listen(s, qlen) < 0)
104     errexit("can't listen on %s port: %s
", service,
105     strerror(errno));
106     return s;
107 }
108 int passiveUDP(const char *service){
109     return passivesock(service,"udp",0);
110 }

这里是用的我实验时的代码，前两个是关于echo服务的客户端与服务器端，有下面运行截图：

后两个是关于time服务的，有下面运行截图：

实验时由于多次运行验证，总会出现端口占用的情况，于是这里每次运行时都输入程序的入口参数（就是main函数里的形参），自选端口，方便至极。还有就是代码里多个函数可以写入多个cpp里，这里偷懒了。