diff options
Diffstat (limited to 'resolv/ns_parse.c')
| -rw-r--r-- | resolv/ns_parse.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/resolv/ns_parse.c b/resolv/ns_parse.c new file mode 100644 index 0000000000..7bbdc41cdf --- /dev/null +++ b/resolv/ns_parse.c @@ -0,0 +1,194 @@ +/* + * 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. + */ + +#ifndef lint +static const char rcsid[] = "$Id$"; +#endif + +/* Import. */ + +#include <sys/types.h> + +#include <netinet/in.h> +#include <arpa/nameser.h> + +#include <errno.h> +#include <resolv.h> +#include <string.h> + +/* Forward. */ + +static void setsection(ns_msg *msg, ns_sect sect); + +/* Macros. */ + +#define RETERR(err) do { __set_errno (err); return (-1); } while (0) + +/* Public. */ + +/* These need to be in the same order as the nres.h:ns_flag enum. */ +struct _ns_flagdata _ns_flagdata[16] = { + { 0x8000, 15 }, /* qr. */ + { 0x7800, 11 }, /* opcode. */ + { 0x0400, 10 }, /* aa. */ + { 0x0200, 9 }, /* tc. */ + { 0x0100, 8 }, /* rd. */ + { 0x0080, 7 }, /* ra. */ + { 0x0040, 6 }, /* z. */ + { 0x0020, 5 }, /* ad. */ + { 0x0010, 4 }, /* cd. */ + { 0x000f, 0 }, /* rcode. */ + { 0x0000, 0 }, /* expansion (1/6). */ + { 0x0000, 0 }, /* expansion (2/6). */ + { 0x0000, 0 }, /* expansion (3/6). */ + { 0x0000, 0 }, /* expansion (4/6). */ + { 0x0000, 0 }, /* expansion (5/6). */ + { 0x0000, 0 }, /* expansion (6/6). */ +}; + +int +ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { + const u_char *optr = ptr; + + for ((void)NULL; count > 0; count--) { + int b, rdlength; + + b = dn_skipname(ptr, eom); + if (b < 0) + RETERR(EMSGSIZE); + ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; + if (section != ns_s_qd) { + if (ptr + NS_INT32SZ + NS_INT16SZ > eom) + RETERR(EMSGSIZE); + ptr += NS_INT32SZ/*TTL*/; + NS_GET16(rdlength, ptr); + ptr += rdlength/*RData*/; + } + } + if (ptr > eom) + RETERR(EMSGSIZE); + return (ptr - optr); +} + +int +ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { + const u_char *eom = msg + msglen; + int i; + + memset(handle, 0x5e, sizeof *handle); + handle->_msg = msg; + handle->_eom = eom; + if (msg + NS_INT16SZ > eom) + RETERR(EMSGSIZE); + NS_GET16(handle->_id, msg); + if (msg + NS_INT16SZ > eom) + RETERR(EMSGSIZE); + NS_GET16(handle->_flags, msg); + for (i = 0; i < ns_s_max; i++) { + if (msg + NS_INT16SZ > eom) + RETERR(EMSGSIZE); + NS_GET16(handle->_counts[i], msg); + } + for (i = 0; i < ns_s_max; i++) + if (handle->_counts[i] == 0) + handle->_sections[i] = NULL; + else { + int b = ns_skiprr(msg, eom, (ns_sect)i, + handle->_counts[i]); + + if (b < 0) + return (-1); + handle->_sections[i] = msg; + msg += b; + } + if (msg != eom) + RETERR(EMSGSIZE); + setsection(handle, ns_s_max); + return (0); +} + +int +ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { + int b; + + /* Make section right. */ + if (section < 0 || section >= ns_s_max) + RETERR(ENODEV); + if (section != handle->_sect) + setsection(handle, section); + + /* Make rrnum right. */ + if (rrnum == -1) + rrnum = handle->_rrnum; + if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) + RETERR(ENODEV); + if (rrnum < handle->_rrnum) + setsection(handle, section); + if (rrnum > handle->_rrnum) { + b = ns_skiprr(handle->_ptr, handle->_eom, section, + rrnum - handle->_rrnum); + + if (b < 0) + return (-1); + handle->_ptr += b; + handle->_rrnum = rrnum; + } + + /* Do the parse. */ + b = dn_expand(handle->_msg, handle->_eom, + handle->_ptr, rr->name, NS_MAXDNAME); + if (b < 0) + return (-1); + handle->_ptr += b; + if (handle->_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) + RETERR(EMSGSIZE); + NS_GET16(rr->type, handle->_ptr); + NS_GET16(rr->rr_class, handle->_ptr); + if (section == ns_s_qd) { + rr->ttl = 0; + rr->rdlength = 0; + rr->rdata = NULL; + } else { + if (handle->_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) + RETERR(EMSGSIZE); + NS_GET32(rr->ttl, handle->_ptr); + NS_GET16(rr->rdlength, handle->_ptr); + if (handle->_ptr + rr->rdlength > handle->_eom) + RETERR(EMSGSIZE); + rr->rdata = handle->_ptr; + handle->_ptr += rr->rdlength; + } + if (++handle->_rrnum > handle->_counts[(int)section]) + setsection(handle, (ns_sect)((int)section + 1)); + + /* All done. */ + return (0); +} + +/* Private. */ + +static void +setsection(ns_msg *msg, ns_sect sect) { + msg->_sect = sect; + if (sect == ns_s_max) { + msg->_rrnum = -1; + msg->_ptr = NULL; + } else { + msg->_rrnum = 0; + msg->_ptr = msg->_sections[(int)sect]; + } +} |