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cope with the possibility that the prefix of a name

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split within a bitstring label might have been compacted to have fewer
labels than what was expected
This commit is contained in:
David Lawrence 2000-11-14 23:51:24 +00:00
parent e28b5084ec
commit e94e2fe29d
1 changed files with 81 additions and 36 deletions
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117
lib/dns/rbt.c
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@ -15,7 +15,7 @@
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: rbt.c,v 1.93 2000/10/25 07:21:29 tale Exp $ */
/* $Id: rbt.c,v 1.94 2000/11/14 23:51:24 tale Exp $ */
/* Principal Authors: DCL */
@ -389,7 +389,7 @@ dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
IS_ROOT(new_current) = ISC_TRUE;
rbt->root = new_current;
*nodep = new_current;
hash_node(rbt, new_current);
result = hash_node(rbt, new_current);
}
return (result);
}
@ -574,37 +574,67 @@ dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
* When bitstring labels are involved, things
* are just a tad more complicated (aren't
* they always?) because the splitting
* has shifted the bits that this name needs,
* as well as adjusted the bit count.
* So there are convolutions to deal with it.
* There are compromises here between
* abstraction and efficiency.
* has shifted the bits that this name needs
* from the end of the label they were in
* to either the beginning of the label or
* even to the previous (lesser significance)
* label if the split was done in a maximally
* sized bitstring label. The bit count has
* been adjusted too, so there are convolutions
* to deal with all the bit movement. Yay,
* I *love* bit labels. Grumble grumble.
*/
if (common_bits > 0) {
dns_label_t label;
dns_name_getlabel(prefix,
unsigned char *p;
unsigned int skip_width;
unsigned int start_label =
dns_name_countlabels(&current_name)
- common_labels,
&label);
- common_labels;
INSIST(dns_label_type(&label) ==
dns_labeltype_bitstring);
/*
* If it is not the first label which
* was split, also copy the label
* before it -- which will essentially
* be a NO-OP unless the preceding
* label is a bitstring and the split
* label was 256 bits. Testing for
* that case is probably roughly
* as expensive as just unconditionally
* copying the preceding label.
*/
if (start_label > 0)
start_label--;
memcpy(NAME(current) +
(label.base - prefix->ndata),
label.base,
label.length);
skip_width =
prefix->offsets[start_label];
dns_name_getlabel(add_name,
dns_name_countlabels(add_name)
- common_labels,
&label);
INSIST(dns_label_type(&label) ==
dns_labeltype_bitstring);
memcpy(NAME(current) + skip_width,
prefix->ndata + skip_width,
prefix->length - skip_width);
add_bits = dns_label_countbits(&label);
/*
* Now add_bits is set to the total
* number of bits in the split label of
* the name being added, and used later
* to determine if the job was
* completed by pushing the
* not-in-common bits down one level.
*/
start_label =
dns_name_countlabels(add_name)
- common_labels;
p = add_name->ndata +
add_name->offsets[start_label];
INSIST(*p == DNS_LABELTYPE_BITSTRING);
add_bits = *(p + 1);
/*
* A bitstring that was split would not
* result in a part of maximal length.
*/
INSIST(add_bits != 0);
} else
add_bits = 0;
@ -635,7 +665,9 @@ dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
ATTRS(current) &= ~DNS_NAMEATTR_ABSOLUTE;
rbt->nodecount++;
hash_node(rbt, new_current);
result = hash_node(rbt, new_current);
if (result != ISC_R_SUCCESS)
break;
if (common_labels ==
dns_name_countlabels(add_name) &&
@ -657,7 +689,8 @@ dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
* nothing more to do to it.
*/
/* The not-in-common parts of the new
/*
* The not-in-common parts of the new
* name will be inserted into the new
* level following this loop (unless
* result != ISC_R_SUCCESS, which
@ -685,8 +718,19 @@ dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
if (result == ISC_R_SUCCESS) {
dns_rbt_addonlevel(new_current, current, order, root);
rbt->nodecount++;
hash_node(rbt, new_current);
*nodep = new_current;
result = hash_node(rbt, new_current);
/*
* XXXDCL Ugh. If hash_node failed, it was because
* there is not enough memory. The node is now unfindable,
* and ideally should be removed. This is kind of tricky,
* and all hell is probably going to break loose throughout
* the rest of the library because of the lack of memory,
* so for fixing up the tree as though no addition had been
* made is skipped. (Actually, this hash_node failing is
* not the only situation in this file where an unexpected
* error can leave things in an incorrect state.)
*/
}
return (result);
@ -1502,14 +1546,15 @@ join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node) {
PARENT(DOWN(down)) = newnode;
rbt->nodecount--;
hash_node(rbt, newnode);
result = hash_node(rbt, newnode);
if (result == ISC_R_SUCCESS) {
unhash_node(rbt, node);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
unhash_node(rbt, node);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
if (newnode != down) {
unhash_node(rbt, down);
isc_mem_put(rbt->mctx, down, NODE_SIZE(down));
if (newnode != down) {
unhash_node(rbt, down);
isc_mem_put(rbt->mctx, down, NODE_SIZE(down));
}
}
}