今天早上6点起床之后练习的一些c的网络编程的基础例子
client1
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int sockfd;
int len;
struct sockaddr_un address;
int result;
char ch = 'A';
/* Create a socket for the client. */
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
/* Name the socket, as agreed with the server. */
address.sun_family = AF_UNIX;
strcpy(address.sun_path, "server_socket");
len = sizeof(address);
/* Now connect our socket to the server's socket. */
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1) {
perror("oops: client1");
exit(1);
}
/* We can now read/write via sockfd. */
write(sockfd, &ch, 1);
read(sockfd, &ch, 1);
printf("char from server = %c\n", ch);
close(sockfd);
exit(0);
}
server1.c
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_un server_address;
struct sockaddr_un client_address;
/* Remove any old socket and create an unnamed socket for the server. */
unlink("server_socket");
server_sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
/* Name the socket. */
server_address.sun_family = AF_UNIX;
strcpy(server_address.sun_path, "server_socket");
server_len = sizeof(server_address);
bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
/* Create a connection queue and wait for clients. */
listen(server_sockfd, 5);
while(1) {
char ch;
printf("server waiting\n");
/* Accept a connection. */
client_len = sizeof(client_address);
client_sockfd = accept(server_sockfd,
(struct sockaddr *)&client_address, &client_len);
/* We can now read/write to client on client_sockfd. */
read(client_sockfd, &ch, 1);
ch++;
write(client_sockfd, &ch, 1);
close(client_sockfd);
}
}
第二个服务器客户端的例子：
client
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int sockfd;
int len;
struct sockaddr_in address;
int result;
char ch = 'A';
/* Create a socket for the client. */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
/* Name the socket, as agreed with the server. */
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr("127.0.0.1");
address.sin_port = htons(9734);
len = sizeof(address);
/* Now connect our socket to the server's socket. */
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1) {
perror("oops: client3");
exit(1);
}
/* We can now read/write via sockfd. */
write(sockfd, &ch, 1);
read(sockfd, &ch, 1);
printf("char from server = %c\n", ch);
close(sockfd);
exit(0);
}
server
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
/* Remove any old socket and create an unnamed socket for the server. */
server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
/* Name the socket. */
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr = htonl(INADDR_ANY);
server_address.sin_port = htons(9734);
server_len = sizeof(server_address);
bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
/* Create a connection queue and wait for clients. */
listen(server_sockfd, 5);
while(1) {
char ch;
printf("server waiting\n");
/* Accept a connection. */
client_len = sizeof(client_address);
client_sockfd = accept(server_sockfd,
(struct sockaddr *)&client_address, &client_len);
/* We can now read/write to client on client_sockfd. */
read(client_sockfd, &ch, 1);
ch++;
write(client_sockfd, &ch, 1);
close(client_sockfd);
}
}
/* As usual, make the appropriate includes and declare the variables. */
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
char *host, **names, **addrs;
struct hostent *hostinfo;
/* Set the host in question to the argument supplied with the getname call,
or default to the user's machine. */
if(argc == 1) {
char myname[256];
gethostname(myname, 255);
host = myname;
}
else
host = argv[1];
/* Make the call to gethostbyname and report an error if no information is found. */
hostinfo = gethostbyname(host);
if(!hostinfo) {
fprintf(stderr, "cannot get info for host: %s\n", host);
exit(1);
}
/* Display the hostname and any aliases it may have. */
printf("results for host %s:\n", host);
printf("Name: %s\n", hostinfo -> h_name);
printf("Aliases:");
names = hostinfo -> h_aliases;
while(*names) {
printf(" %s", *names);
names++;
}
printf("\n");
/* Warn and exit if the host in question isn't an IP host. */
if(hostinfo -> h_addrtype != AF_INET) {
fprintf(stderr, "not an IP host!\n");
exit(1);
}
/* Otherwise, display the IP address(es). */
addrs = hostinfo -> h_addr_list;
while(*addrs) {
printf(" %s", inet_ntoa(*(struct in_addr *)*addrs));
addrs++;
}
printf("\n");
exit(0);
}
/* Start with the usual includes and declarations. */
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
char *host;
int sockfd;
int len, result;
struct sockaddr_in address;
struct hostent *hostinfo;
struct servent *servinfo;
char buffer[128];
if(argc == 1)
host = "localhost";
else
host = argv[1];
/* Find the host address and report an error if none is found. */
hostinfo = gethostbyname(host);
if(!hostinfo) {
fprintf(stderr, "no host: %s\n", host);
exit(1);
}
/* Check that the daytime service exists on the host. */
servinfo = getservbyname("daytime", "tcp");
if(!servinfo) {
fprintf(stderr,"no daytime service\n");
exit(1);
}
printf("daytime port is %d\n", ntohs(servinfo -> s_port));
/* Create a socket. */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
/* Construct the address for use with connect... */
address.sin_family = AF_INET;
address.sin_port = servinfo -> s_port;
address.sin_addr = *(struct in_addr *)*hostinfo -> h_addr_list;
len = sizeof(address);
/* ...then connect and get the information. */
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1) {
perror("oops: getdate");
exit(1);
}
result = read(sockfd, buffer, sizeof(buffer));
buffer[result] = '\0';
printf("read %d bytes: %s", result, buffer);
close(sockfd);
exit(0);
}
getdate-udp
/* Start with the usual includes and declarations. */
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
char *host;
int sockfd;
int len, result;
struct sockaddr_in address;
struct hostent *hostinfo;
struct servent *servinfo;
char buffer[128];
if(argc == 1)
host = "localhost";
else
host = argv[1];
/* Find the host address and report an error if none is found. */
hostinfo = gethostbyname(host);
if(!hostinfo) {
fprintf(stderr, "no host: %s\n", host);
exit(1);
}
/* Check that the daytime service exists on the host. */
servinfo = getservbyname("daytime", "udp");
if(!servinfo) {
fprintf(stderr,"no daytime service\n");
exit(1);
}
printf("daytime port is %d\n", ntohs(servinfo -> s_port));
/* Create a UDP socket. */
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
/* Construct the address for use with sendto/recvfrom... */
address.sin_family = AF_INET;
address.sin_port = servinfo -> s_port;
address.sin_addr = *(struct in_addr *)*hostinfo -> h_addr_list;
len = sizeof(address);
result = sendto(sockfd, buffer, 1, 0, (struct sockaddr *)&address, len);
result = recvfrom(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr *)&address, &len);
buffer[result] = '\0';
printf("read %d bytes: %s", result, buffer);
close(sockfd);
exit(0);
}
