| commit | author | age | ||
| caef9a | 1 | /********************* |
| OB | 2 | * simple TCP-server * |
| 3 | *********************/ | |
| 4 | #include <fcntl.h> | |
| 5 | #include <unistd.h> | |
| 6 | #include <sys/socket.h> | |
| 7 | #include <sys/types.h> | |
| 8 | #include <stdlib.h> | |
| 9 | #include <stdio.h> | |
| 10 | #include <netdb.h> | |
| 11 | #include <string.h> | |
| 12 | ||
| 13 | int main(int argc, char **argv) { | |
| 14 | unsigned short port; /* port to bind to */ | |
| 15 | char buffer[80]; /* i/o buffer */ | |
| 16 | struct sockaddr_in client; /* ip address of client */ | |
| 17 | struct sockaddr_in server; /* ip address of server */ | |
| 18 | struct hostent *hostnm; /* dest-hostname to connect to */ | |
| 19 | int s; /* socket */ | |
| 20 | int ns; /* socket connected to client */ | |
| 21 | int namelen; /* length of client name */ | |
| 22 | int optval=1; | |
| 23 | int s_optlen=0; | |
| 24 | ssize_t recvbytes; /* received bytes */ | |
| 25 | ||
| 26 | /* check for needed parameters */ | |
| 27 | if(argc!=3) { | |
| 28 | fprintf(stderr, "%s portnumber\n", argv[0]); | |
| 29 | exit(1); | |
| 30 | } | |
| 31 | hostnm=gethostbyname(argv[1]); | |
| 32 | ||
| 33 | /* port to int */ | |
| 34 | port=(unsigned short) atoi(argv[2]); | |
| 35 | ||
| 36 | /* generating socket */ | |
| 37 | if((s=socket(AF_INET, SOCK_STREAM,0))<0){ | |
| 38 | perror("Error:"); | |
| 39 | exit(2); | |
| 40 | } | |
| 41 | ||
| 42 | /* set socket options so that we can reuse the port */ | |
| 43 | setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &optval, s_optlen); | |
| 44 | ||
| 45 | /* bind to socket */ | |
| 46 | server.sin_family = AF_INET; | |
| 47 | server.sin_port = htons(port); | |
| 48 | server.sin_addr.s_addr = *((unsigned long *)hostnm->h_addr); | |
| 49 | ||
| 50 | if(bind(s, (struct sockaddr *)&server, sizeof(server))<0){ | |
| 51 | perror("Error:"); | |
| 52 | exit(3); | |
| 53 | } | |
| 54 | ||
| 55 | /* waiting for connections */ | |
| 56 | if(listen(s,1)!=0){ | |
| 57 | perror("Error:"); | |
| 58 | exit(4); | |
| 59 | } | |
| 60 | ||
| 61 | /* get connection */ | |
| 62 | namelen=sizeof(client); | |
| 63 | ||
| 64 | /* we loop forever here to avoid stopping the server */ | |
| 65 | while(1) { | |
| 66 | if((ns=accept(s, (struct sockaddr *)&client, &namelen))==-1){ | |
| 67 | perror("Error:"); | |
| 68 | exit(5); | |
| 69 | } | |
| 70 | ||
| 71 | /* write welcome banner to user */ | |
| 72 | snprintf(buffer, 54, "Welcome to the echo server, type a single x to quit.\n"); | |
| 73 | send(ns, buffer, 54, 0); | |
| 74 | /* loop until we get an x as first char */ | |
| 75 | do { | |
| 76 | /* get messages */ | |
| 77 | recvbytes=recv(ns, buffer, sizeof(buffer), 0); | |
| 78 | if(recvbytes == -1){ | |
| 79 | perror("Error:"); | |
| 80 | exit(6); | |
| 81 | } | |
| 82 | ||
| 83 | /* send answer */ | |
| 84 | if(send(ns, buffer, recvbytes, 0) <0){ | |
| 85 | perror("Error:"); | |
| 86 | exit(7); | |
| 87 | } | |
| 88 | } while (buffer[0] != 'x'); | |
| 89 | ||
| 90 | /* client session closed on request, say bye bye */ | |
| 91 | snprintf(buffer, 30, "Good bye, see you next time.\n"); | |
| 92 | send(ns, buffer, 30, 0); | |
| 93 | ||
| 94 | /* close connection */ | |
| 95 | close(ns); | |
| 96 | } | |
| 97 | ||
| 98 | /* close listener */ | |
| 99 | close(s); | |
| 100 | printf("server exiting\n"); | |
| 101 | return(0); | |
| 102 | } | |
