/* ** Routines to open a TCP connection ** ** New version that supports the old (pre 4.2 BSD) socket calls, ** and systems with the old (pre 4.2 BSD) hostname lookup stuff. ** Compile-time options are: ** ** OLDSOCKET - different args for socket() and connect() ** ** Erik E. Fair ** */ /* Uncomment the following line if you are using old socket calls */ /* #define OLDSOCKET */ #include "stdinclude.h" #include #include #include #include #include #include #include #include #include #include #include "get_tcp_conn.h" #include "get_tcp_conn.proto.h" extern int errno; extern int close(); /* ** Take the name of an internet host in ASCII (this may either be its ** official host name or internet number (with or without enclosing ** backets [])), and return a list of internet addresses. ** ** returns NULL for failure to find the host name in the local database, ** or for a bad internet address spec. */ unsigned long ** name_to_address(char *host) { static u_long *host_addresses[2]; static u_long haddr; if (host == (char *) NULL) { return ((u_long **) NULL); } host_addresses[0] = &haddr; host_addresses[1] = (u_long *) NULL; /* * Is this an ASCII internet address? (either of [10.0.0.78] or * 10.0.0.78). We get away with the second test because hostnames * and domain labels are not allowed to begin in numbers. * (cf. RFC952, RFC882). */ if (*host == '[' || isdigit(*host)) { char namebuf[128]; register char *cp = namebuf; /* * strip brackets [] or anything else we don't want. */ while (*host != '\0' && cp < &namebuf[sizeof(namebuf)]) { if (isdigit(*host) || *host == '.') *cp++ = *host++; /* copy */ else host++; /* skip */ } *cp = '\0'; haddr = inet_addr(namebuf); return (&host_addresses[0]); } else { struct hostent *hstp = gethostbyname(host); if (hstp == NULL) { return ((u_long **) NULL);/* no such host */ } if (hstp->h_length != sizeof(u_long)) abort(); /* this is fundamental */ return ((u_long **) hstp->h_addr_list); } } u_short gservice(char *serv, char *proto) { if (serv == (char *) NULL || proto == (char *) NULL) return ((u_short) 0); if (isdigit(*serv)) { return (htons((u_short) (atoi(serv)))); } else { struct servent *srvp = getservbyname(serv, proto); if (srvp == (struct servent *) NULL) return ((u_short) 0); return ((u_short) srvp->s_port); } } /* ** given a host name (either name or internet address) and port number ** give us a TCP connection to the ** requested service at the requested host (or give us FAIL). */ int get_tcp_conn(host, port) char *host; int port; { register int sock; u_long **addrlist; struct sockaddr_in sadr; #ifdef OLDSOCKET struct sockproto sp; sp.sp_family = (u_short) AF_INET; sp.sp_protocol = (u_short) IPPROTO_TCP; #endif if ((addrlist = name_to_address(host)) == (u_long **) NULL) { return (NOHOST); } sadr.sin_family = (u_short) AF_INET; /* Only internet for now */ sadr.sin_port = htons(port); for (; *addrlist != (u_long *) NULL; addrlist++) { bcopy((caddr_t) * addrlist, (caddr_t) & sadr.sin_addr, sizeof(sadr.sin_addr)); #ifdef OLDSOCKET if ((sock = socket(SOCK_STREAM, &sp, (struct sockaddr *) NULL, 0)) < 0) return (FAIL); if (connect(sock, (struct sockaddr *) & sadr) < 0) { #else if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) return (FAIL); if (connect(sock, (struct sockaddr *) & sadr, sizeof(sadr)) < 0) { #endif int e_save = errno; fprintf(stderr, "%s [%s] port %d: %d\n", host, inet_ntoa(sadr.sin_addr), port, errno); (void) close(sock); /* dump descriptor */ errno = e_save; } else return (sock); } return (FAIL); }