/* tree.c Routines for manipulating parse trees... */ /* * Copyright (c) 1995, 1996, 1997 The Internet Software Consortium. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of The Internet Software Consortium nor the names * of its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. */ #ifndef lint static char copyright[] = "$Id: tree.c,v 1.1.1.2 1997/06/03 02:49:34 mellon Exp $ Copyright (c) 1995, 1996, 1997 The Internet Software Consortium. All rights reserved.\n"; #endif /* not lint */ #include "dhcpd.h" static TIME tree_evaluate_recurse PROTO ((int *, unsigned char **, int *, struct tree *)); static TIME do_host_lookup PROTO ((int *, unsigned char **, int *, struct dns_host_entry *)); static void do_data_copy PROTO ((int *, unsigned char **, int *, unsigned char *, int)); pair cons (car, cdr) caddr_t car; pair cdr; { pair foo = (pair)dmalloc (sizeof *foo, "cons"); if (!foo) error ("no memory for cons."); foo -> car = car; foo -> cdr = cdr; return foo; } struct tree_cache *tree_cache (tree) struct tree *tree; { struct tree_cache *tc; tc = new_tree_cache ("tree_cache"); if (!tc) return 0; tc -> value = (unsigned char *)0; tc -> len = tc -> buf_size = 0; tc -> timeout = 0; tc -> tree = tree; return tc; } struct tree *tree_host_lookup (name) char *name; { struct tree *nt; nt = new_tree ("tree_host_lookup"); if (!nt) error ("No memory for host lookup tree node."); nt -> op = TREE_HOST_LOOKUP; nt -> data.host_lookup.host = enter_dns_host (name); return nt; } struct dns_host_entry *enter_dns_host (name) char *name; { struct dns_host_entry *dh; if (!(dh = (struct dns_host_entry *)dmalloc (sizeof (struct dns_host_entry), "enter_dns_host")) || !(dh -> hostname = dmalloc (strlen (name) + 1, "enter_dns_host"))) error ("Can't allocate space for new host."); strcpy (dh -> hostname, name); dh -> data = (unsigned char *)0; dh -> data_len = 0; dh -> buf_len = 0; dh -> timeout = 0; return dh; } struct tree *tree_const (data, len) unsigned char *data; int len; { struct tree *nt; if (!(nt = new_tree ("tree_const")) || !(nt -> data.const_val.data = (unsigned char *)dmalloc (len, "tree_const"))) error ("No memory for constant data tree node."); nt -> op = TREE_CONST; memcpy (nt -> data.const_val.data, data, len); nt -> data.const_val.len = len; return nt; } struct tree *tree_concat (left, right) struct tree *left, *right; { struct tree *nt; /* If we're concatenating a null tree to a non-null tree, just return the non-null tree; if both trees are null, return a null tree. */ if (!left) return right; if (!right) return left; /* If both trees are constant, combine them. */ if (left -> op == TREE_CONST && right -> op == TREE_CONST) { unsigned char *buf = dmalloc (left -> data.const_val.len + right -> data.const_val.len, "tree_concat"); if (!buf) error ("No memory to concatenate constants."); memcpy (buf, left -> data.const_val.data, left -> data.const_val.len); memcpy (buf + left -> data.const_val.len, right -> data.const_val.data, right -> data.const_val.len); dfree (left -> data.const_val.data, "tree_concat"); dfree (right -> data.const_val.data, "tree_concat"); left -> data.const_val.data = buf; left -> data.const_val.len += right -> data.const_val.len; free_tree (right, "tree_concat"); return left; } /* Otherwise, allocate a new node to concatenate the two. */ if (!(nt = new_tree ("tree_concat"))) error ("No memory for data tree concatenation node."); nt -> op = TREE_CONCAT; nt -> data.concat.left = left; nt -> data.concat.right = right; return nt; } struct tree *tree_limit (tree, limit) struct tree *tree; int limit; { struct tree *rv; /* If the tree we're limiting is constant, limit it now. */ if (tree -> op == TREE_CONST) { if (tree -> data.const_val.len > limit) tree -> data.const_val.len = limit; return tree; } /* Otherwise, put in a node which enforces the limit on evaluation. */ rv = new_tree ("tree_limit"); if (!rv) return (struct tree *)0; rv -> op = TREE_LIMIT; rv -> data.limit.tree = tree; rv -> data.limit.limit = limit; return rv; } int tree_evaluate (tree_cache) struct tree_cache *tree_cache; { unsigned char *bp = tree_cache -> value; int bc = tree_cache -> buf_size; int bufix = 0; /* If there's no tree associated with this cache, it evaluates to a constant and that was detected at startup. */ if (!tree_cache -> tree) return 1; /* Try to evaluate the tree without allocating more memory... */ tree_cache -> timeout = tree_evaluate_recurse (&bufix, &bp, &bc, tree_cache -> tree); /* No additional allocation needed? */ if (bufix <= bc) { tree_cache -> len = bufix; return 1; } /* If we can't allocate more memory, return with what we have (maybe nothing). */ if (!(bp = (unsigned char *)dmalloc (bufix, "tree_evaluate"))) return 0; /* Record the change in conditions... */ bc = bufix; bufix = 0; /* Note that the size of the result shouldn't change on the second call to tree_evaluate_recurse, since we haven't changed the ``current'' time. */ tree_evaluate_recurse (&bufix, &bp, &bc, tree_cache -> tree); /* Free the old buffer if needed, then store the new buffer location and size and return. */ if (tree_cache -> value) dfree (tree_cache -> value, "tree_evaluate"); tree_cache -> value = bp; tree_cache -> len = bufix; tree_cache -> buf_size = bc; return 1; } static TIME tree_evaluate_recurse (bufix, bufp, bufcount, tree) int *bufix; unsigned char **bufp; int *bufcount; struct tree *tree; { int limit; TIME t1, t2; switch (tree -> op) { case TREE_CONCAT: t1 = tree_evaluate_recurse (bufix, bufp, bufcount, tree -> data.concat.left); t2 = tree_evaluate_recurse (bufix, bufp, bufcount, tree -> data.concat.right); if (t1 > t2) return t2; return t1; case TREE_HOST_LOOKUP: return do_host_lookup (bufix, bufp, bufcount, tree -> data.host_lookup.host); case TREE_CONST: do_data_copy (bufix, bufp, bufcount, tree -> data.const_val.data, tree -> data.const_val.len); t1 = MAX_TIME; return t1; case TREE_LIMIT: limit = *bufix + tree -> data.limit.limit; t1 = tree_evaluate_recurse (bufix, bufp, bufcount, tree -> data.limit.tree); *bufix = limit; return t1; default: warn ("Bad node id in tree: %d."); t1 = MAX_TIME; return t1; } } static TIME do_host_lookup (bufix, bufp, bufcount, dns) int *bufix; unsigned char **bufp; int *bufcount; struct dns_host_entry *dns; { struct hostent *h; int i; int new_len; #ifdef DEBUG_EVAL debug ("time: now = %d dns = %d %d diff = %d", cur_time, dns -> timeout, cur_time - dns -> timeout); #endif /* If the record hasn't timed out, just copy the data and return. */ if (cur_time <= dns -> timeout) { #ifdef DEBUG_EVAL debug ("easy copy: %x %d %x", dns -> data, dns -> data_len, dns -> data ? *(int *)(dns -> data) : 0); #endif do_data_copy (bufix, bufp, bufcount, dns -> data, dns -> data_len); return dns -> timeout; } #ifdef DEBUG_EVAL debug ("Looking up %s", dns -> hostname); #endif /* Otherwise, look it up... */ h = gethostbyname (dns -> hostname); if (!h) { #ifndef NO_H_ERRNO switch (h_errno) { case HOST_NOT_FOUND: #endif warn ("%s: host unknown.", dns -> hostname); #ifndef NO_H_ERRNO break; case TRY_AGAIN: warn ("%s: temporary name server failure", dns -> hostname); break; case NO_RECOVERY: warn ("%s: name server failed", dns -> hostname); break; case NO_DATA: warn ("%s: no A record associated with address", dns -> hostname); } #endif /* !NO_H_ERRNO */ /* Okay to try again after a minute. */ return cur_time + 60; } #ifdef DEBUG_EVAL debug ("Lookup succeeded; first address is %x", h -> h_addr_list [0]); #endif /* Count the number of addresses we got... */ for (i = 0; h -> h_addr_list [i]; i++) ; /* Do we need to allocate more memory? */ new_len = i * h -> h_length; if (dns -> buf_len < i) { unsigned char *buf = (unsigned char *)dmalloc (new_len, "do_host_lookup"); /* If we didn't get more memory, use what we have. */ if (!buf) { new_len = dns -> buf_len; if (!dns -> buf_len) { dns -> timeout = cur_time + 60; return dns -> timeout; } } else { if (dns -> data) dfree (dns -> data, "do_host_lookup"); dns -> data = buf; dns -> buf_len = new_len; } } /* Addresses are conveniently stored one to the buffer, so we have to copy them out one at a time... :'( */ for (i = 0; i < new_len / h -> h_length; i++) { memcpy (dns -> data + h -> h_length * i, h -> h_addr_list [i], h -> h_length); } #ifdef DEBUG_EVAL debug ("dns -> data: %x h -> h_addr_list [0]: %x", *(int *)(dns -> data), h -> h_addr_list [0]); #endif dns -> data_len = new_len; /* Set the timeout for an hour from now. XXX This should really use the time on the DNS reply. */ dns -> timeout = cur_time + 3600; #ifdef DEBUG_EVAL debug ("hard copy: %x %d %x", dns -> data, dns -> data_len, *(int *)(dns -> data)); #endif do_data_copy (bufix, bufp, bufcount, dns -> data, dns -> data_len); return dns -> timeout; } static void do_data_copy (bufix, bufp, bufcount, data, len) int *bufix; unsigned char **bufp; int *bufcount; unsigned char *data; int len; { int space = *bufcount - *bufix; /* If there's more space than we need, use only what we need. */ if (space > len) space = len; /* Copy as much data as will fit, then increment the buffer index by the amount we actually had to copy, which could be more. */ if (space > 0) memcpy (*bufp + *bufix, data, space); *bufix += len; }