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construct/authd/reslib.c
Elizabeth Myers 394b8dde17 authd: allow querying the list of DNS servers. 
This was an asston of pain, and it still feels "dirty" as it introduces
an async call where there normally wouldn't be one. Better
implementation more than welcome.
2016-03-08 02:53:25 -06:00

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/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. 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.
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/*
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/* Original copyright ISC as above.
* Code modified specifically for ircd use from the following orginal files
* in bind ...
*
* res_comp.c
* ns_name.c
* ns_netint.c
* res_init.c
*
* - Dianora
*/
#include "stdinc.h"
#include "ircd_defs.h"
#include "common.h"
#include "ircd.h"
#include "res.h"
#include "reslib.h"
#include "match.h"
#include "logger.h"
#define NS_TYPE_ELT 0x40 /* EDNS0 extended label type */
#define DNS_LABELTYPE_BITSTRING 0x41
#define DNS_MAXLINE 128
struct rb_sockaddr_storage irc_nsaddr_list[IRCD_MAXNS];
int irc_nscount = 0;
char irc_domain[IRCD_RES_HOSTLEN + 1];
static const char digitvalue[256] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
};
static int parse_resvconf(void);
static void add_nameserver(const char *);
static const char digits[] = "0123456789";
static int labellen(const unsigned char *lp);
static int special(int ch);
static int printable(int ch);
static int irc_decode_bitstring(const char **cpp, char *dn, const char *eom);
static int irc_ns_name_compress(const char *src, unsigned char *dst, size_t dstsiz,
const unsigned char **dnptrs, const unsigned char **lastdnptr);
static int irc_dn_find(const unsigned char *, const unsigned char *, const unsigned char * const *,
const unsigned char * const *);
static int irc_encode_bitsring(const char **, const char *, unsigned char **, unsigned char **,
const char *);
static int irc_ns_name_uncompress(const unsigned char *, const unsigned char *,
const unsigned char *, char *, size_t);
static int irc_ns_name_unpack(const unsigned char *, const unsigned char *,
const unsigned char *, unsigned char *,
size_t);
static int irc_ns_name_ntop(const char *, char *, size_t);
static int irc_ns_name_skip(const unsigned char **, const unsigned char *);
static int mklower(int ch);
int
irc_res_init(void)
{
irc_nscount = 0;
parse_resvconf();
if (irc_nscount == 0)
add_nameserver("127.0.0.1");
return 0;
}
/* parse_resvconf()
*
* inputs - NONE
* output - -1 if failure 0 if success
* side effects - fills in irc_nsaddr_list
*/
static int
parse_resvconf(void)
{
char *p;
char *opt;
char *arg;
char input[DNS_MAXLINE];
FILE *file;
/* XXX "/etc/resolv.conf" should be from a define in setup.h perhaps
* for cygwin support etc. this hardcodes it to unix for now -db
*/
if ((file = fopen("/etc/resolv.conf", "r")) == NULL)
return -1;
while (fgets(input, sizeof(input), file) != NULL)
{
/* blow away any newline */
if ((p = strpbrk(input, "\r\n")) != NULL)
*p = '\0';
p = input;
/* skip until something thats not a space is seen */
while (isspace(*p))
p++;
/* if at this point, have a '\0' then continue */
if (*p == '\0')
continue;
/* Ignore comment lines immediately */
if (*p == '#' || *p == ';')
continue;
/* skip until a space is found */
opt = p;
while (!isspace(*p) && *p != '\0')
p++;
if (*p == '\0')
continue; /* no arguments?.. ignore this line */
/* blow away the space character */
*p++ = '\0';
/* skip these spaces that are before the argument */
while (isspace(*p))
p++;
/* Now arg should be right where p is pointing */
arg = p;
if ((p = strpbrk(arg, " \t")) != NULL)
*p = '\0'; /* take the first word */
if (strcasecmp(opt, "domain") == 0)
rb_strlcpy(irc_domain, arg, sizeof(irc_domain));
else if (strcasecmp(opt, "nameserver") == 0)
add_nameserver(arg);
}
fclose(file);
return 0;
}
/* add_nameserver()
*
* input - either an IPV4 address in dotted quad
* or an IPV6 address in : format
* output - NONE
* side effects - entry in irc_nsaddr_list is filled in as needed
*/
static void
add_nameserver(const char *arg)
{
struct addrinfo hints, *res;
/* Done max number of nameservers? */
if (irc_nscount >= IRCD_MAXNS)
return;
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
if (getaddrinfo(arg, "domain", &hints, &res))
return;
if (res == NULL)
return;
memcpy(&irc_nsaddr_list[irc_nscount], res->ai_addr, res->ai_addrlen);
SET_SS_LEN(&irc_nsaddr_list[irc_nscount], res->ai_addrlen);
irc_nscount++;
freeaddrinfo(res);
}
/*
* Expand compressed domain name 'comp_dn' to full domain name.
* 'msg' is a pointer to the begining of the message,
* 'eomorig' points to the first location after the message,
* 'exp_dn' is a pointer to a buffer of size 'length' for the result.
* Return size of compressed name or -1 if there was an error.
*/
int
irc_dn_expand(const unsigned char *msg, const unsigned char *eom,
const unsigned char *src, char *dst, int dstsiz)
{
int n = irc_ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
if (n > 0 && dst[0] == '.')
dst[0] = '\0';
return(n);
}
/*
* irc_ns_name_uncompress(msg, eom, src, dst, dstsiz)
* Expand compressed domain name to presentation format.
* return:
* Number of bytes read out of `src', or -1 (with errno set).
* note:
* Root domain returns as "." not "".
*/
static int
irc_ns_name_uncompress(const unsigned char *msg, const unsigned char *eom,
const unsigned char *src, char *dst, size_t dstsiz)
{
unsigned char tmp[NS_MAXCDNAME];
int n;
if ((n = irc_ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
return(-1);
if (irc_ns_name_ntop((char*)tmp, dst, dstsiz) == -1)
return(-1);
return(n);
}
/*
* irc_ns_name_unpack(msg, eom, src, dst, dstsiz)
* Unpack a domain name from a message, source may be compressed.
* return:
* -1 if it fails, or consumed octets if it succeeds.
*/
static int
irc_ns_name_unpack(const unsigned char *msg, const unsigned char *eom,
const unsigned char *src, unsigned char *dst,
size_t dstsiz)
{
const unsigned char *srcp, *dstlim;
unsigned char *dstp;
int n, len, checked, l;
len = -1;
checked = 0;
dstp = dst;
srcp = src;
dstlim = dst + dstsiz;
if (srcp < msg || srcp >= eom) {
errno = EMSGSIZE;
return (-1);
}
/* Fetch next label in domain name. */
while ((n = *srcp++) != 0) {
/* Check for indirection. */
switch (n & NS_CMPRSFLGS) {
case 0:
case NS_TYPE_ELT:
/* Limit checks. */
if ((l = labellen(srcp - 1)) < 0) {
errno = EMSGSIZE;
return(-1);
}
if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
errno = EMSGSIZE;
return (-1);
}
checked += l + 1;
*dstp++ = n;
memcpy(dstp, srcp, l);
dstp += l;
srcp += l;
break;
case NS_CMPRSFLGS:
if (srcp >= eom) {
errno = EMSGSIZE;
return (-1);
}
if (len < 0)
len = srcp - src + 1;
srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
if (srcp < msg || srcp >= eom) { /* Out of range. */
errno = EMSGSIZE;
return (-1);
}
checked += 2;
/*
* Check for loops in the compressed name;
* if we've looked at the whole message,
* there must be a loop.
*/
if (checked >= eom - msg) {
errno = EMSGSIZE;
return (-1);
}
break;
default:
errno = EMSGSIZE;
return (-1); /* flag error */
}
}
*dstp = '\0';
if (len < 0)
len = srcp - src;
return (len);
}
/*
* irc_ns_name_ntop(src, dst, dstsiz)
* Convert an encoded domain name to printable ascii as per RFC1035.
* return:
* Number of bytes written to buffer, or -1 (with errno set)
* notes:
* The root is returned as "."
* All other domains are returned in non absolute form
*/
static int
irc_ns_name_ntop(const char *src, char *dst, size_t dstsiz)
{
const char *cp;
char *dn, *eom;
unsigned char c;
unsigned int n;
int l;
cp = src;
dn = dst;
eom = dst + dstsiz;
while ((n = *cp++) != 0) {
if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
/* Some kind of compression pointer. */
errno = EMSGSIZE;
return (-1);
}
if (dn != dst) {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '.';
}
if ((l = labellen((const unsigned char*)(cp - 1))) < 0) {
errno = EMSGSIZE; /* XXX */
return(-1);
}
if (dn + l >= eom) {
errno = EMSGSIZE;
return (-1);
}
if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
int m;
if (n != DNS_LABELTYPE_BITSTRING) {
/* XXX: labellen should reject this case */
errno = EINVAL;
return(-1);
}
if ((m = irc_decode_bitstring(&cp, dn, eom)) < 0)
{
errno = EMSGSIZE;
return(-1);
}
dn += m;
continue;
}
for ((void)NULL; l > 0; l--) {
c = *cp++;
if (special(c)) {
if (dn + 1 >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\\';
*dn++ = (char)c;
} else if (!printable(c)) {
if (dn + 3 >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\\';
*dn++ = digits[c / 100];
*dn++ = digits[(c % 100) / 10];
*dn++ = digits[c % 10];
} else {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = (char)c;
}
}
}
if (dn == dst) {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '.';
}
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\0';
return (dn - dst);
}
/*
* Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
* Return the size of the compressed name or -1.
* 'length' is the size of the array pointed to by 'comp_dn'.
*/
static int
irc_dn_comp(const char *src, unsigned char *dst, int dstsiz,
const unsigned char **dnptrs, const unsigned char **lastdnptr)
{
return(irc_ns_name_compress(src, dst, (size_t)dstsiz,
(const unsigned char **)dnptrs,
(const unsigned char **)lastdnptr));
}
/*
* Skip over a compressed domain name. Return the size or -1.
*/
int
irc_dn_skipname(const unsigned char *ptr, const unsigned char *eom) {
const unsigned char *saveptr = ptr;
if (irc_ns_name_skip(&ptr, eom) == -1)
return(-1);
return(ptr - saveptr);
}
/*
* ns_name_skip(ptrptr, eom)
* Advance *ptrptr to skip over the compressed name it points at.
* return:
* 0 on success, -1 (with errno set) on failure.
*/
static int
irc_ns_name_skip(const unsigned char **ptrptr, const unsigned char *eom)
{
const unsigned char *cp;
unsigned int n;
int l;
cp = *ptrptr;
while (cp < eom && (n = *cp++) != 0)
{
/* Check for indirection. */
switch (n & NS_CMPRSFLGS)
{
case 0: /* normal case, n == len */
cp += n;
continue;
case NS_TYPE_ELT: /* EDNS0 extended label */
if ((l = labellen(cp - 1)) < 0)
{
errno = EMSGSIZE; /* XXX */
return(-1);
}
cp += l;
continue;
case NS_CMPRSFLGS: /* indirection */
cp++;
break;
default: /* illegal type */
errno = EMSGSIZE;
return(-1);
}
break;
}
if (cp > eom)
{
errno = EMSGSIZE;
return (-1);
}
*ptrptr = cp;
return(0);
}
unsigned int
irc_ns_get16(const unsigned char *src)
{
unsigned int dst;
IRC_NS_GET16(dst, src);
return(dst);
}
unsigned long
irc_ns_get32(const unsigned char *src)
{
unsigned long dst;
IRC_NS_GET32(dst, src);
return(dst);
}
void
irc_ns_put16(unsigned int src, unsigned char *dst)
{
IRC_NS_PUT16(src, dst);
}
void
irc_ns_put32(unsigned long src, unsigned char *dst)
{
IRC_NS_PUT32(src, dst);
}
/* From ns_name.c */
/*
* special(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this characted special ("in need of quoting") ?
* return:
* boolean.
*/
static int
special(int ch)
{
switch (ch)
{
case 0x22: /* '"' */
case 0x2E: /* '.' */
case 0x3B: /* ';' */
case 0x5C: /* '\\' */
case 0x28: /* '(' */
case 0x29: /* ')' */
/* Special modifiers in zone files. */
case 0x40: /* '@' */
case 0x24: /* '$' */
return(1);
default:
return(0);
}
}
static int
labellen(const unsigned char *lp)
{
int bitlen;
unsigned char l = *lp;
if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS)
{
/* should be avoided by the caller */
return(-1);
}
if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT)
{
if (l == DNS_LABELTYPE_BITSTRING)
{
if ((bitlen = *(lp + 1)) == 0)
bitlen = 256;
return((bitlen + 7 ) / 8 + 1);
}
return(-1); /* unknwon ELT */
}
return(l);
}
/*
* printable(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this character visible and not a space when printed ?
* return:
* boolean.
*/
static int
printable(int ch)
{
return(ch > 0x20 && ch < 0x7f);
}
static int
irc_decode_bitstring(const char **cpp, char *dn, const char *eom)
{
const char *cp = *cpp;
char *beg = dn, tc;
int b, blen, plen;
if ((blen = (*cp & 0xff)) == 0)
blen = 256;
plen = (blen + 3) / 4;
plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
if (dn + plen >= eom)
return(-1);
cp++;
dn += sprintf(dn, "\\[x");
for (b = blen; b > 7; b -= 8, cp++)
dn += sprintf(dn, "%02x", *cp & 0xff);
if (b > 4) {
tc = *cp++;
dn += sprintf(dn, "%02x", tc & (0xff << (8 - b)));
} else if (b > 0) {
tc = *cp++;
dn += sprintf(dn, "%1x",
((tc >> 4) & 0x0f) & (0x0f << (4 - b)));
}
dn += sprintf(dn, "/%d]", blen);
*cpp = cp;
return(dn - beg);
}
/*
* irc_ns_name_pton(src, dst, dstsiz)
* Convert a ascii string into an encoded domain name as per RFC1035.
* return:
* -1 if it fails
* 1 if string was fully qualified
* 0 is string was not fully qualified
* notes:
* Enforces label and domain length limits.
*/
static int
irc_ns_name_pton(const char *src, unsigned char *dst, size_t dstsiz)
{
unsigned char *label, *bp, *eom;
char *cp;
int c, n, escaped, e = 0;
escaped = 0;
bp = dst;
eom = dst + dstsiz;
label = bp++;
while ((c = *src++) != 0) {
if (escaped) {
if (c == '[') { /* start a bit string label */
if ((cp = strchr(src, ']')) == NULL) {
errno = EINVAL; /* ??? */
return(-1);
}
if ((e = irc_encode_bitsring(&src,
cp + 2,
&label,
&bp,
(const char *)eom))
!= 0) {
errno = e;
return(-1);
}
escaped = 0;
label = bp++;
if ((c = *src++) == 0)
goto done;
else if (c != '.') {
errno = EINVAL;
return(-1);
}
continue;
}
else if ((cp = strchr(digits, c)) != NULL) {
n = (cp - digits) * 100;
if ((c = *src++) == 0 ||
(cp = strchr(digits, c)) == NULL) {
errno = EMSGSIZE;
return (-1);
}
n += (cp - digits) * 10;
if ((c = *src++) == 0 ||
(cp = strchr(digits, c)) == NULL) {
errno = EMSGSIZE;
return (-1);
}
n += (cp - digits);
if (n > 255) {
errno = EMSGSIZE;
return (-1);
}
c = n;
}
escaped = 0;
} else if (c == '\\') {
escaped = 1;
continue;
} else if (c == '.') {
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
errno = EMSGSIZE;
return (-1);
}
if (label >= eom) {
errno = EMSGSIZE;
return (-1);
}
*label = c;
/* Fully qualified ? */
if (*src == '\0') {
if (c != 0) {
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = '\0';
}
if ((bp - dst) > NS_MAXCDNAME) {
errno = EMSGSIZE;
return (-1);
}
return (1);
}
if (c == 0 || *src == '.') {
errno = EMSGSIZE;
return (-1);
}
label = bp++;
continue;
}
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = (unsigned char)c;
}
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
errno = EMSGSIZE;
return (-1);
}
done:
if (label >= eom) {
errno = EMSGSIZE;
return (-1);
}
*label = c;
if (c != 0) {
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = 0;
}
if ((bp - dst) > NS_MAXCDNAME)
{ /* src too big */
errno = EMSGSIZE;
return (-1);
}
return (0);
}
/*
* irc_ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr)
* Pack domain name 'domain' into 'comp_dn'.
* return:
* Size of the compressed name, or -1.
* notes:
* 'dnptrs' is an array of pointers to previous compressed names.
* dnptrs[0] is a pointer to the beginning of the message. The array
* ends with NULL.
* 'lastdnptr' is a pointer to the end of the array pointed to
* by 'dnptrs'.
* Side effects:
* The list of pointers in dnptrs is updated for labels inserted into
* the message as we compress the name. If 'dnptr' is NULL, we don't
* try to compress names. If 'lastdnptr' is NULL, we don't update the
* list.
*/
static int
irc_ns_name_pack(const unsigned char *src, unsigned char *dst, int dstsiz,
const unsigned char **dnptrs, const unsigned char **lastdnptr)
{
unsigned char *dstp;
const unsigned char **cpp, **lpp, *eob, *msg;
const unsigned char *srcp;
int n, l, first = 1;
srcp = src;
dstp = dst;
eob = dstp + dstsiz;
lpp = cpp = NULL;
if (dnptrs != NULL) {
if ((msg = *dnptrs++) != NULL) {
for (cpp = dnptrs; *cpp != NULL; cpp++)
(void)NULL;
lpp = cpp; /* end of list to search */
}
} else
msg = NULL;
/* make sure the domain we are about to add is legal */
l = 0;
do {
int l0;
n = *srcp;
if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
errno = EMSGSIZE;
return (-1);
}
if ((l0 = labellen(srcp)) < 0) {
errno = EINVAL;
return(-1);
}
l += l0 + 1;
if (l > NS_MAXCDNAME) {
errno = EMSGSIZE;
return (-1);
}
srcp += l0 + 1;
} while (n != 0);
/* from here on we need to reset compression pointer array on error */
srcp = src;
do {
/* Look to see if we can use pointers. */
n = *srcp;
if (n != 0 && msg != NULL) {
l = irc_dn_find(srcp, msg, (const unsigned char * const *)dnptrs,
(const unsigned char * const *)lpp);
if (l >= 0) {
if (dstp + 1 >= eob) {
goto cleanup;
}
*dstp++ = (l >> 8) | NS_CMPRSFLGS;
*dstp++ = l % 256;
return (dstp - dst);
}
/* Not found, save it. */
if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
(dstp - msg) < 0x4000 && first) {
*cpp++ = dstp;
*cpp = NULL;
first = 0;
}
}
/* copy label to buffer */
if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
/* Should not happen. */
goto cleanup;
}
n = labellen(srcp);
if (dstp + 1 + n >= eob) {
goto cleanup;
}
memcpy(dstp, srcp, n + 1);
srcp += n + 1;
dstp += n + 1;
} while (n != 0);
if (dstp > eob) {
cleanup:
if (msg != NULL)
*lpp = NULL;
errno = EMSGSIZE;
return (-1);
}
return(dstp - dst);
}
static int
irc_ns_name_compress(const char *src, unsigned char *dst, size_t dstsiz,
const unsigned char **dnptrs, const unsigned char **lastdnptr)
{
unsigned char tmp[NS_MAXCDNAME];
if (irc_ns_name_pton(src, tmp, sizeof tmp) == -1)
return(-1);
return(irc_ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
}
static int
irc_encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
unsigned char **dst, const char *eom)
{
int afterslash = 0;
const char *cp = *bp;
char *tp, c;
const char *beg_blen;
char *end_blen = NULL;
int value = 0, count = 0, tbcount = 0, blen = 0;
beg_blen = end_blen = NULL;
/* a bitstring must contain at least 2 characters */
if (end - cp < 2)
return(EINVAL);
/* XXX: currently, only hex strings are supported */
if (*cp++ != 'x')
return(EINVAL);
if (!isxdigit((*cp) & 0xff)) /* reject '\[x/BLEN]' */
return(EINVAL);
for (tp = (char*)(dst + 1); cp < end && tp < eom; cp++) {
switch((c = *cp)) {
case ']': /* end of the bitstring */
if (afterslash) {
if (beg_blen == NULL)
return(EINVAL);
blen = (int)strtol(beg_blen, &end_blen, 10);
if (*end_blen != ']')
return(EINVAL);
}
if (count)
*tp++ = ((value << 4) & 0xff);
cp++; /* skip ']' */
goto done;
case '/':
afterslash = 1;
break;
default:
if (afterslash) {
if (!isdigit(c&0xff))
return(EINVAL);
if (beg_blen == NULL) {
if (c == '0') {
/* blen never begings with 0 */
return(EINVAL);
}
beg_blen = cp;
}
} else {
if (!isxdigit(c&0xff))
return(EINVAL);
value <<= 4;
value += digitvalue[(int)c];
count += 4;
tbcount += 4;
if (tbcount > 256)
return(EINVAL);
if (count == 8) {
*tp++ = value;
count = 0;
}
}
break;
}
}
done:
if (cp >= end || tp >= eom)
return(EMSGSIZE);
/*
* bit length validation:
* If a <length> is present, the number of digits in the <bit-data>
* MUST be just sufficient to contain the number of bits specified
* by the <length>. If there are insignificant bits in a final
* hexadecimal or octal digit, they MUST be zero.
* RFC 2673, Section 3.2.
*/
if (blen > 0) {
int traillen;
if (((blen + 3) & ~3) != tbcount)
return(EINVAL);
traillen = tbcount - blen; /* between 0 and 3 */
if (((value << (8 - traillen)) & 0xff) != 0)
return(EINVAL);
}
else
blen = tbcount;
if (blen == 256)
blen = 0;
/* encode the type and the significant bit fields */
**labelp = DNS_LABELTYPE_BITSTRING;
**dst = blen;
*bp = cp;
*dst = (unsigned char*)tp;
return(0);
}
/*
* dn_find(domain, msg, dnptrs, lastdnptr)
* Search for the counted-label name in an array of compressed names.
* return:
* offset from msg if found, or -1.
* notes:
* dnptrs is the pointer to the first name on the list,
* not the pointer to the start of the message.
*/
static int
irc_dn_find(const unsigned char *domain, const unsigned char *msg,
const unsigned char * const *dnptrs,
const unsigned char * const *lastdnptr)
{
const unsigned char *dn, *cp, *sp;
const unsigned char * const *cpp;
unsigned int n;
for (cpp = dnptrs; cpp < lastdnptr; cpp++)
{
sp = *cpp;
/*
* terminate search on:
* root label
* compression pointer
* unusable offset
*/
while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
(sp - msg) < 0x4000) {
dn = domain;
cp = sp;
while ((n = *cp++) != 0) {
/*
* check for indirection
*/
switch (n & NS_CMPRSFLGS) {
case 0: /* normal case, n == len */
n = labellen(cp - 1); /* XXX */
if (n != *dn++)
goto next;
for ((void)NULL; n > 0; n--)
if (mklower(*dn++) !=
mklower(*cp++))
goto next;
/* Is next root for both ? */
if (*dn == '\0' && *cp == '\0')
return (sp - msg);
if (*dn)
continue;
goto next;
case NS_CMPRSFLGS: /* indirection */
cp = msg + (((n & 0x3f) << 8) | *cp);
break;
default: /* illegal type */
errno = EMSGSIZE;
return (-1);
}
}
next: ;
sp += *sp + 1;
}
}
errno = ENOENT;
return (-1);
}
/*
* Thinking in noninternationalized USASCII (per the DNS spec),
* convert this character to lower case if it's upper case.
*/
static int
mklower(int ch)
{
if (ch >= 0x41 && ch <= 0x5A)
return(ch + 0x20);
return(ch);
}
/* From resolv/mkquery.c */
/*
* Form all types of queries.
* Returns the size of the result or -1.
*/
int
irc_res_mkquery(
const char *dname, /* domain name */
int class, int type, /* class and type of query */
unsigned char *buf, /* buffer to put query */
int buflen) /* size of buffer */
{
HEADER *hp;
unsigned char *cp;
int n;
const unsigned char *dnptrs[20], **dpp, **lastdnptr;
/*
* Initialize header fields.
*/
if ((buf == NULL) || (buflen < HFIXEDSZ))
return (-1);
memset(buf, 0, HFIXEDSZ);
hp = (HEADER *)(void *)buf;
hp->id = 0;
hp->opcode = QUERY;
hp->rd = 1; /* recurse */
hp->rcode = NO_ERRORS;
cp = buf + HFIXEDSZ;
buflen -= HFIXEDSZ;
dpp = dnptrs;
*dpp++ = buf;
*dpp++ = NULL;
lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
if ((buflen -= QFIXEDSZ) < 0)
return (-1);
if ((n = irc_dn_comp(dname, cp, buflen, dnptrs, lastdnptr)) < 0)
return (-1);
cp += n;
buflen -= n;
IRC_NS_PUT16(type, cp);
IRC_NS_PUT16(class, cp);
hp->qdcount = htons(1);
return (cp - buf);
}
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