New file |
| | |
| | | /********************* |
| | | * simple TCP-server * |
| | | *********************/ |
| | | #include <fcntl.h> |
| | | #include <unistd.h> |
| | | #include <sys/socket.h> |
| | | #include <sys/types.h> |
| | | #include <stdlib.h> |
| | | #include <stdio.h> |
| | | #include <netdb.h> |
| | | #include <string.h> |
| | | |
| | | int main(int argc, char **argv) { |
| | | unsigned short port; /* port to bind to */ |
| | | char buffer[80]; /* i/o buffer */ |
| | | struct sockaddr_in client; /* ip address of client */ |
| | | struct sockaddr_in server; /* ip address of server */ |
| | | struct hostent *hostnm; /* dest-hostname to connect to */ |
| | | int s; /* socket */ |
| | | int ns; /* socket connected to client */ |
| | | int namelen; /* length of client name */ |
| | | int optval=1; |
| | | int s_optlen=0; |
| | | ssize_t recvbytes; /* received bytes */ |
| | | |
| | | /* check for needed parameters */ |
| | | if(argc!=3) { |
| | | fprintf(stderr, "%s portnumber\n", argv[0]); |
| | | exit(1); |
| | | } |
| | | hostnm=gethostbyname(argv[1]); |
| | | |
| | | /* port to int */ |
| | | port=(unsigned short) atoi(argv[2]); |
| | | |
| | | /* generating socket */ |
| | | if((s=socket(AF_INET, SOCK_STREAM,0))<0){ |
| | | perror("Error:"); |
| | | exit(2); |
| | | } |
| | | |
| | | /* set socket options so that we can reuse the port */ |
| | | setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &optval, s_optlen); |
| | | |
| | | /* bind to socket */ |
| | | server.sin_family = AF_INET; |
| | | server.sin_port = htons(port); |
| | | server.sin_addr.s_addr = *((unsigned long *)hostnm->h_addr); |
| | | |
| | | if(bind(s, (struct sockaddr *)&server, sizeof(server))<0){ |
| | | perror("Error:"); |
| | | exit(3); |
| | | } |
| | | |
| | | /* waiting for connections */ |
| | | if(listen(s,1)!=0){ |
| | | perror("Error:"); |
| | | exit(4); |
| | | } |
| | | |
| | | /* get connection */ |
| | | namelen=sizeof(client); |
| | | |
| | | /* we loop forever here to avoid stopping the server */ |
| | | while(1) { |
| | | if((ns=accept(s, (struct sockaddr *)&client, &namelen))==-1){ |
| | | perror("Error:"); |
| | | exit(5); |
| | | } |
| | | |
| | | /* write welcome banner to user */ |
| | | snprintf(buffer, 54, "Welcome to the echo server, type a single x to quit.\n"); |
| | | send(ns, buffer, 54, 0); |
| | | /* loop until we get an x as first char */ |
| | | do { |
| | | /* get messages */ |
| | | recvbytes=recv(ns, buffer, sizeof(buffer), 0); |
| | | if(recvbytes == -1){ |
| | | perror("Error:"); |
| | | exit(6); |
| | | } |
| | | |
| | | /* send answer */ |
| | | if(send(ns, buffer, recvbytes, 0) <0){ |
| | | perror("Error:"); |
| | | exit(7); |
| | | } |
| | | } while (buffer[0] != 'x'); |
| | | |
| | | /* client session closed on request, say bye bye */ |
| | | snprintf(buffer, 30, "Good bye, see you next time.\n"); |
| | | send(ns, buffer, 30, 0); |
| | | |
| | | /* close connection */ |
| | | close(ns); |
| | | } |
| | | |
| | | /* close listener */ |
| | | close(s); |
| | | printf("server exiting\n"); |
| | | return(0); |
| | | } |