/* Realms of Aurealis Rerouter */ /* James Rhone */ #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/wait.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <netdb.h> #include <sys/time.h> #include <fcntl.h> #include <ctype.h> #include <string.h> #include <signal.h> #include <sys/un.h> #include <netdb.h> #include <errno.h> #include <netinet/in.h> void watch(int port); int init_socket(int port); void nonblock(int s); int reaper(); int goodnight(); extern int errno; #define MAX_STRING_LENGTH 8192 /* global mother descriptor */ int mother; int main(int argc, char **argv) { int port; char buf[128]; if (argc != 2) { printf("usage: %s <port#>\n",*argv); exit(0); } if ((port = atoi(argv[1])) <= 1024) { fputs("Illegal port #\n", stderr); exit(0); } watch(port); return 1; } int reaper() { int status; int pid; while ((pid = wait3(&status, WNOHANG, (struct rusage *)0)) > 0) printf("Child %d exited.\n\r", pid); } int goodnight() { printf("Signal received. Closing mother connection.\n"); printf("Killing children.\n"); close(mother); exit(3); } int passivesock(char *service, char *protocol, int qlen) { struct servent *pse; struct protoent *ppe; struct sockaddr_in sin; int s, type; u_short portbase = 0; bzero((char *)&sin, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = INADDR_ANY; if (pse = getservbyname(service, protocol)) sin.sin_port = htons(ntohs((u_short)pse->s_port) + portbase); else if ((sin.sin_port = htons((u_short)atoi(service))) == 0) { printf("can't get %s service entry\n",service); exit(0); } if ((ppe = getprotobyname(protocol)) == 0) { printf("can't get %s proto entry\n",protocol); exit(0); } if (!strcmp(protocol, "udp")) type = SOCK_DGRAM; else type = SOCK_STREAM; s = socket(PF_INET, type, ppe->p_proto); if (s < 0) { printf("cant create socket\n"); exit (0); } if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) { printf("cant bind\n"); exit (0); } if (type == SOCK_STREAM && listen(s, qlen) < 0) { printf("cant listen on stream socket\n"); exit (0); } return s; } int passiveTCP(char *service, int qlen) { return passivesock(service, "tcp", qlen); } void interface_to_roa(int sok) { struct sockaddr_in srvadr_in; struct hostent *sp; int addrlen; int mud; char buf[MAX_STRING_LENGTH]; int cnt; int opt; addrlen = sizeof(struct sockaddr_in); memset((char *)&srvadr_in, 0, addrlen); srvadr_in.sin_family = AF_INET; sp = gethostbyname("sc27.dreamscape.com"); if (!sp) { printf("could not get hostname.\n"); exit(1); } srvadr_in.sin_addr.s_addr = ((struct in_addr *)(sp->h_addr))->s_addr; srvadr_in.sin_port = htons(4000); mud = socket(PF_INET, SOCK_STREAM, 0); if (mud < 0) { perror("Init-mud-socket"); exit(0); } #if defined(SO_SNDBUF) opt = MAX_STRING_LENGTH + 128; if (setsockopt(mud, SOL_SOCKET, SO_SNDBUF, (char *) &opt, sizeof(opt)) < 0) { perror("setsockopt SNDBUF"); exit(1); } #endif opt = 1; if (setsockopt(mud, SOL_SOCKET, SO_REUSEADDR, (char *) & opt, sizeof (opt)) < 0) { perror ("setsockopt REUSEADDR"); exit (0); } #if defined(SO_LINGER) { struct linger ld; ld.l_onoff = 0; ld.l_linger = 0; if (setsockopt(mud, SOL_SOCKET, SO_LINGER, (char *) &ld, sizeof(ld)) < 0) { perror("setsockopt LINGER"); exit(1); } } #endif if (connect(mud, (struct sockaddr *)&srvadr_in, addrlen) < 0) { printf("couldnt connect to roa.sunyit.edu.\n"); perror("connect: "); exit(1); } nonblock(mud); nonblock(sok); printf("Child %d connected to RoA.\n", getpid()); for ( ; ; ) { errno = 0; if ((cnt = recv(mud, buf, MAX_STRING_LENGTH, 0)) < 0) if (errno != EAGAIN) { perror("first recv: "); break; } if (cnt > 0) { buf[cnt] = '\0'; if ((cnt = send(sok, buf, strlen(buf), 0)) < 0) { *buf = '\0'; break; } } errno = 0; if ((cnt = recv(sok, buf, MAX_STRING_LENGTH, 0)) < 0) if (errno != EAGAIN) { perror("second recv: "); break; } if (cnt > 0) { buf[cnt] = '\0'; if ((cnt = send(mud, buf, strlen(buf), 0)) < 0) { *buf = '\0'; break; } } } close(sok); close(mud); printf("Child %d connection closed.\n", getpid()); exit(3); } void watch(int port) { int con; signal (SIGCHLD, (void *) reaper); signal (SIGINT, (void *) goodnight); signal (SIGTERM, (void *) goodnight); signal (SIGHUP, (void *) goodnight); signal (SIGABRT, (void *) goodnight); mother = init_socket(port); printf("mother socket opened on port %d\n",port); for (; ; ) { con = accept(mother, (struct sockaddr *) 0, 0); if (con < 0) continue; if (!fork()) { printf("Connection detected, Child %d forked.\n",getpid()); interface_to_roa(con); close(con); exit(0); } else close(con); } } int init_socket(int port) { int s; char *opt; char hostname[1024]; struct sockaddr_in sa; struct hostent *hp; bzero(&sa, sizeof(struct sockaddr_in )); gethostname(hostname, 1023); hp = gethostbyname(hostname); if (!hp) { perror("gethostbyname"); exit(0); } sa.sin_family = hp->h_addrtype; sa.sin_port = htons(port); s = socket(AF_INET, SOCK_STREAM, 0); if (s < 0) { perror("Init-socket"); exit(0); } if (setsockopt (s, SOL_SOCKET, SO_REUSEADDR, (char *) & opt, sizeof (opt)) < 0) { perror ("setsockopt REUSEADDR"); exit (0); } #ifdef USE_LINGER struct linger ld; ld.l_onoff = 1; ld.l_linger = 1000; if (setsockopt(s, SOL_SOCKET, SO_LINGER, &ld, sizeof(ld)) < 0) { perror("setsockopt LINGER"); exit(0); } #endif if (bind(s, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); close(s); exit(0); } listen(s, 5); return(s); } void nonblock(int s) { int flags; flags = fcntl(s, F_GETFL); flags |= O_NONBLOCK; if (fcntl(s, F_SETFL, flags) < 0) { perror("Fatal error executing nonblock (comm.c)"); exit(1); } }