/*
* util/data/dname.h - domain name routines
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the NLNET LABS 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 COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDER 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.
*/
/**
* \file
*
* This file contains functions to deal with domain names (dnames).
*
* Some of the functions deal with domain names as a wireformat buffer,
* with a length.
*/
#ifndef UTIL_DATA_DNAME_H
#define UTIL_DATA_DNAME_H
#include "util/storage/lruhash.h"
struct sldns_buffer;
/** max number of compression ptrs to follow */
#define MAX_COMPRESS_PTRS 256
/**
* Determine length of dname in buffer, no compression ptrs allowed,
* @param query: the ldns buffer, current position at start of dname.
* at end, position is at end of the dname.
* @return: 0 on parse failure, or length including ending 0 of dname.
*/
size_t query_dname_len(struct sldns_buffer* query);
/**
* Determine if dname in memory is correct. no compression ptrs allowed.
* @param dname: where dname starts in memory.
* @param len: dname is not allowed to exceed this length (i.e. of allocation).
* @return length of dname if dname is ok, 0 on a parse error.
*/
size_t dname_valid(uint8_t* dname, size_t len);
/** lowercase query dname */
void query_dname_tolower(uint8_t* dname);
/**
* lowercase pkt dname (follows compression pointers)
* @param pkt: the packet, used to follow compression pointers. Position
* is unchanged.
* @param dname: start of dname in packet.
*/
void pkt_dname_tolower(struct sldns_buffer* pkt, uint8_t* dname);
/**
* Compare query dnames (uncompressed storage). The Dnames passed do not
* have to be lowercased, comparison routine does this.
*
* This routine is special, in that the comparison that it does corresponds
* with the canonical comparison needed when comparing dnames inside rdata
* for RR types that need canonicalization. That means that the first byte
* that is smaller (possibly after lowercasing) makes an RR smaller, or the
* shortest name makes an RR smaller.
*
* This routine does not compute the canonical order needed for NSEC
* processing.
*
* Dnames have to be valid format.
* @param d1: dname to compare
* @param d2: dname to compare
* @return: -1, 0, or +1 depending on comparison results.
* Sort order is first difference found. not the canonical ordering.
*/
int query_dname_compare(uint8_t* d1, uint8_t* d2);
/**
* Determine correct, compressed, dname present in packet.
* Checks for parse errors.
* @param pkt: packet to read from (from current start position).
* @return: 0 on parse error.
* At exit the position is right after the (compressed) dname.
* Compression pointers are followed and checked for loops.
* The uncompressed wireformat length is returned.
*/
size_t pkt_dname_len(struct sldns_buffer* pkt);
/**
* Compare dnames in packet (compressed). Dnames must be valid.
* routine performs lowercasing, so the packet casing is preserved.
* @param pkt: packet, used to resolve compression pointers.
* @param d1: dname to compare
* @param d2: dname to compare
* @return: -1, 0, or +1 depending on comparison results.
* Sort order is first difference found. not the canonical ordering.
*/
int dname_pkt_compare(struct sldns_buffer* pkt, uint8_t* d1, uint8_t* d2);
/**
* Hash dname, label by label, lowercasing, into hashvalue.
* Dname in query format (not compressed).
* @param dname: dname to hash.
* @param h: initial hash value.
* @return: result hash value.
*/
hashvalue_t dname_query_hash(uint8_t* dname, hashvalue_t h);
/**
* Hash dname, label by label, lowercasing, into hashvalue.
* Dname in pkt format (compressed).
* @param pkt: packet, for resolving compression pointers.
* @param dname: dname to hash, pointer to the pkt buffer.
* Must be valid format. No loops, etc.
* @param h: initial hash value.
* @return: result hash value.
* Result is the same as dname_query_hash, even if compression is used.
*/
hashvalue_t dname_pkt_hash(struct sldns_buffer* pkt, uint8_t* dname, hashvalue_t h);
/**
* Copy over a valid dname and decompress it.
* @param pkt: packet to resolve compression pointers.
* @param to: buffer of size from pkt_len function to hold result.
* @param dname: pointer into packet where dname starts.
*/
void dname_pkt_copy(struct sldns_buffer* pkt, uint8_t* to, uint8_t* dname);
/**
* Copy over a valid dname to a packet.
* @param pkt: packet to copy to.
* @param dname: dname to copy.
* @return: 0 if not enough space in buffer.
*/
int dname_buffer_write(struct sldns_buffer* pkt, uint8_t* dname);
/**
* Count the number of labels in an uncompressed dname in memory.
* @param dname: pointer to uncompressed dname.
* @return: count of labels, including root label, "com." has 2 labels.
*/
int dname_count_labels(uint8_t* dname);
/**
* Count labels and dname length both, for uncompressed dname in memory.
* @param dname: pointer to uncompressed dname.
* @param size: length of dname, including root label.
* @return: count of labels, including root label, "com." has 2 labels.
*/
int dname_count_size_labels(uint8_t* dname, size_t* size);
/**
* Compare dnames, sorted not canonical, but by label.
* Such that zone contents follows zone apex.
* @param d1: first dname. pointer to uncompressed wireformat.
* @param labs1: number of labels in first dname.
* @param d2: second dname. pointer to uncompressed wireformat.
* @param labs2: number of labels in second dname.
* @param mlabs: number of labels that matched exactly (the shared topdomain).
* @return: 0 for equal, -1 smaller, or +1 d1 larger than d2.
*/
int dname_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, int* mlabs);
/**
* See if domain name d1 is a strict subdomain of d2.
* That is a subdomain, but not equal.
* @param d1: domain name, uncompressed wireformat
* @param labs1: number of labels in d1, including root label.
* @param d2: domain name, uncompressed wireformat
* @param labs2: number of labels in d2, including root label.
* @return true if d1 is a subdomain of d2, but not equal to d2.
*/
int dname_strict_subdomain(uint8_t* d1, int labs1, uint8_t* d2, int labs2);
/**
* Like dname_strict_subdomain but counts labels
* @param d1: domain name, uncompressed wireformat
* @param d2: domain name, uncompressed wireformat
* @return true if d1 is a subdomain of d2, but not equal to d2.
*/
int dname_strict_subdomain_c(uint8_t* d1, uint8_t* d2);
/**
* Counts labels. Tests is d1 is a subdomain of d2.
* @param d1: domain name, uncompressed wireformat
* @param d2: domain name, uncompressed wireformat
* @return true if d1 is a subdomain of d2.
*/
int dname_subdomain_c(uint8_t* d1, uint8_t* d2);
/**
* Debug helper. Print wireformat dname to output.
* @param out: like stdout or a file.
* @param pkt: if not NULL, the packet for resolving compression ptrs.
* @param dname: pointer to (start of) dname.
*/
void dname_print(FILE* out, struct sldns_buffer* pkt, uint8_t* dname);
/**
* Debug helper. Print dname to given string buffer (string buffer must
* be at least 255 chars + 1 for the 0, in printable form.
* This may lose information (? for nonprintable characters, or & if
* the name is too long, # for a bad label length).
* @param dname: uncompressed wireformat.
* @param str: buffer of 255+1 length.
*/
void dname_str(uint8_t* dname, char* str);
/**
* Returns true if the uncompressed wireformat dname is the root "."
* @param dname: the dname to check
* @return true if ".", false if not.
*/
int dname_is_root(uint8_t* dname);
/**
* Snip off first label from a dname, returning the parent zone.
* @param dname: from what to strip off. uncompressed wireformat.
* @param len: length, adjusted to become less.
* @return stripped off, or "." if input was ".".
*/
void dname_remove_label(uint8_t** dname, size_t* len);
/**
* Snip off first N labels from a dname, returning the parent zone.
* @param dname: from what to strip off. uncompressed wireformat.
* @param len: length, adjusted to become less.
* @param n: number of labels to strip off (from the left).
* if 0, nothing happens.
* @return stripped off, or "." if input was ".".
*/
void dname_remove_labels(uint8_t** dname, size_t* len, int n);
/**
* Count labels for the RRSIG signature label field.
* Like a normal labelcount, but "*" wildcard and "." root are not counted.
* @param dname: valid uncompressed wireformat.
* @return number of labels like in RRSIG; '*' and '.' are not counted.
*/
int dname_signame_label_count(uint8_t* dname);
/**
* Return true if the label is a wildcard, *.example.com.
* @param dname: valid uncompressed wireformat.
* @return true if wildcard, or false.
*/
int dname_is_wild(uint8_t* dname);
/**
* Compare dnames, Canonical in rfc4034 sense, but by label.
* Such that zone contents follows zone apex.
*
* @param d1: first dname. pointer to uncompressed wireformat.
* @param labs1: number of labels in first dname.
* @param d2: second dname. pointer to uncompressed wireformat.
* @param labs2: number of labels in second dname.
* @param mlabs: number of labels that matched exactly (the shared topdomain).
* @return: 0 for equal, -1 smaller, or +1 d1 larger than d2.
*/
int dname_canon_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2,
int* mlabs);
/**
* Canonical dname compare. Takes care of counting labels.
* Per rfc 4034 canonical order.
*
* @param d1: first dname. pointer to uncompressed wireformat.
* @param d2: second dname. pointer to uncompressed wireformat.
* @return: 0 for equal, -1 smaller, or +1 d1 larger than d2.
*/
int dname_canonical_compare(uint8_t* d1, uint8_t* d2);
/**
* Get the shared topdomain between two names. Root "." or longer.
* @param d1: first dname. pointer to uncompressed wireformat.
* @param d2: second dname. pointer to uncompressed wireformat.
* @return pointer to shared topdomain. Ptr to a part of d1.
*/
uint8_t* dname_get_shared_topdomain(uint8_t* d1, uint8_t* d2);
#endif /* UTIL_DATA_DNAME_H */
