network_cmds-480.tar.gz

[apple/network_cmds.git] / unbound / util / data / msgparse.c

/* 
 * util/data/msgparse.c - parse wireformat DNS messages.
 * 
 * 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
 * Routines for message parsing a packet buffer to a descriptive structure.
 */
#include "config.h"
#include "util/data/msgparse.h"
#include "util/data/dname.h"
#include "util/data/packed_rrset.h"
#include "util/storage/lookup3.h"
#include "util/regional.h"
#include "ldns/rrdef.h"
#include "ldns/sbuffer.h"
#include "ldns/parseutil.h"
#include "ldns/wire2str.h"

/** smart comparison of (compressed, valid) dnames from packet */
static int
smart_compare(sldns_buffer* pkt, uint8_t* dnow, 
        uint8_t* dprfirst, uint8_t* dprlast)
{
        if(LABEL_IS_PTR(*dnow)) {
                /* ptr points to a previous dname */
                uint8_t* p = sldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1]));
                if( p == dprfirst || p == dprlast )
                        return 0;
                /* prev dname is also a ptr, both ptrs are the same. */
                if(LABEL_IS_PTR(*dprlast) &&
                        dprlast[0] == dnow[0] && dprlast[1] == dnow[1])
                        return 0;
        }
        return dname_pkt_compare(pkt, dnow, dprlast);
}

/**
 * Allocate new rrset in region, fill with data.
 */
static struct rrset_parse* 
new_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen, 
        uint16_t type, uint16_t dclass, hashvalue_t hash, 
        uint32_t rrset_flags, sldns_pkt_section section, 
        struct regional* region)
{
        struct rrset_parse* p = regional_alloc(region, sizeof(*p));
        if(!p) return NULL;
        p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)];
        msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p;
        p->rrset_all_next = 0;
        if(msg->rrset_last)
                msg->rrset_last->rrset_all_next = p;
        else    msg->rrset_first = p;
        msg->rrset_last = p;
        p->hash = hash;
        p->section = section;
        p->dname = dname;
        p->dname_len = dnamelen;
        p->type = type;
        p->rrset_class = dclass;
        p->flags = rrset_flags;
        p->rr_count = 0;
        p->size = 0;
        p->rr_first = 0;
        p->rr_last = 0;
        p->rrsig_count = 0;
        p->rrsig_first = 0;
        p->rrsig_last = 0;
        return p;
}

/** See if next rrset is nsec at zone apex */
static int
nsec_at_apex(sldns_buffer* pkt)
{
        /* we are at ttl position in packet. */
        size_t pos = sldns_buffer_position(pkt);
        uint16_t rdatalen;
        if(sldns_buffer_remaining(pkt) < 7) /* ttl+len+root */
                return 0; /* eek! */
        sldns_buffer_skip(pkt, 4); /* ttl */;
        rdatalen = sldns_buffer_read_u16(pkt);
        if(sldns_buffer_remaining(pkt) < rdatalen) {
                sldns_buffer_set_position(pkt, pos);
                return 0; /* parse error happens later */
        }
        /* must validate the nsec next domain name format */
        if(pkt_dname_len(pkt) == 0) {
                sldns_buffer_set_position(pkt, pos);
                return 0; /* parse error */
        }

        /* see if SOA bit is set. */
        if(sldns_buffer_position(pkt) < pos+4+rdatalen) {
                /* nsec type bitmap contains items */
                uint8_t win, blen, bits;
                /* need: windownum, bitmap len, firstbyte */
                if(sldns_buffer_position(pkt)+3 > pos+4+rdatalen) {
                        sldns_buffer_set_position(pkt, pos);
                        return 0; /* malformed nsec */
                }
                win = sldns_buffer_read_u8(pkt);
                blen = sldns_buffer_read_u8(pkt);
                bits = sldns_buffer_read_u8(pkt);
                /* 0window always first window. bitlen >=1 or parse
                   error really. bit 0x2 is SOA. */
                if(win == 0 && blen >= 1 && (bits & 0x02)) {
                        sldns_buffer_set_position(pkt, pos);
                        return 1;
                }
        }

        sldns_buffer_set_position(pkt, pos);
        return 0;
}

/** Calculate rrset flags */
static uint32_t
pkt_rrset_flags(sldns_buffer* pkt, uint16_t type, sldns_pkt_section sec)
{
        uint32_t f = 0;
        if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) {
                f |= PACKED_RRSET_NSEC_AT_APEX;
        } else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) {
                f |= PACKED_RRSET_SOA_NEG;
        }
        return f;
}

hashvalue_t
pkt_hash_rrset(sldns_buffer* pkt, uint8_t* dname, uint16_t type, 
        uint16_t dclass, uint32_t rrset_flags)
{
        /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
        /* this routine handles compressed names */
        hashvalue_t h = 0xab;
        h = dname_pkt_hash(pkt, dname, h);
        h = hashlittle(&type, sizeof(type), h);         /* host order */
        h = hashlittle(&dclass, sizeof(dclass), h);     /* netw order */
        h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
        return h;
}

/** create partial dname hash for rrset hash */
static hashvalue_t
pkt_hash_rrset_first(sldns_buffer* pkt, uint8_t* dname)
{
        /* works together with pkt_hash_rrset_rest */
        /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
        /* this routine handles compressed names */
        hashvalue_t h = 0xab;
        h = dname_pkt_hash(pkt, dname, h);
        return h;
}

/** create a rrset hash from a partial dname hash */
static hashvalue_t
pkt_hash_rrset_rest(hashvalue_t dname_h, uint16_t type, uint16_t dclass, 
        uint32_t rrset_flags)
{
        /* works together with pkt_hash_rrset_first */
        /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
        hashvalue_t h;
        h = hashlittle(&type, sizeof(type), dname_h);   /* host order */
        h = hashlittle(&dclass, sizeof(dclass), h);     /* netw order */
        h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
        return h;
}

/** compare rrset_parse with data */
static int
rrset_parse_equals(struct rrset_parse* p, sldns_buffer* pkt, hashvalue_t h, 
        uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, 
        uint16_t type, uint16_t dclass)
{
        if(p->hash == h && p->dname_len == dnamelen && p->type == type &&
                p->rrset_class == dclass && p->flags == rrset_flags &&
                dname_pkt_compare(pkt, dname, p->dname) == 0)
                return 1;
        return 0;
}


struct rrset_parse*
msgparse_hashtable_lookup(struct msg_parse* msg, sldns_buffer* pkt, 
        hashvalue_t h, uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, 
        uint16_t type, uint16_t dclass)
{
        struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)];
        while(p) {
                if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen,
                        type, dclass))
                        return p;
                p = p->rrset_bucket_next;
        }
        return NULL;
}

/** return type networkformat that rrsig in packet covers */
static int
pkt_rrsig_covered(sldns_buffer* pkt, uint8_t* here, uint16_t* type)
{
        size_t pos = sldns_buffer_position(pkt);
        sldns_buffer_set_position(pkt, (size_t)(here-sldns_buffer_begin(pkt)));
        /* ttl + len + size of small rrsig(rootlabel, no signature) */
        if(sldns_buffer_remaining(pkt) < 4+2+19)
                return 0;
        sldns_buffer_skip(pkt, 4); /* ttl */
        if(sldns_buffer_read_u16(pkt) < 19) /* too short */ {
                sldns_buffer_set_position(pkt, pos);
                return 0;
        }
        *type = sldns_buffer_read_u16(pkt);
        sldns_buffer_set_position(pkt, pos);
        return 1;
}

/** true if covered type equals prevtype */
static int
pkt_rrsig_covered_equals(sldns_buffer* pkt, uint8_t* here, uint16_t type)
{
        uint16_t t;
        if(pkt_rrsig_covered(pkt, here, &t) && t == type)
                return 1;
        return 0;
}

void
msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset)
{
        struct rrset_parse** p;
        p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ];
        while(*p) {
                if(*p == rrset) {
                        *p = rrset->rrset_bucket_next;
                        return;
                }
                p = &( (*p)->rrset_bucket_next );
        }
}

/** change section of rrset from previous to current section */
static void
change_section(struct msg_parse* msg, struct rrset_parse* rrset,
        sldns_pkt_section section)
{
        struct rrset_parse *p, *prev;
        /* remove from list */
        if(section == rrset->section)
                return;
        p = msg->rrset_first;
        prev = 0;
        while(p) {
                if(p == rrset) {
                        if(prev) prev->rrset_all_next = p->rrset_all_next;
                        else    msg->rrset_first = p->rrset_all_next;
                        if(msg->rrset_last == rrset)
                                msg->rrset_last = prev;
                        break;
                }
                prev = p;
                p = p->rrset_all_next;
        }
        /* remove from count */
        switch(rrset->section) {
                case LDNS_SECTION_ANSWER: msg->an_rrsets--; break;
                case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break;
                case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break;
                default: log_assert(0);
        }
        /* insert at end of list */
        rrset->rrset_all_next = 0;
        if(msg->rrset_last)
                msg->rrset_last->rrset_all_next = rrset;
        else    msg->rrset_first = rrset;
        msg->rrset_last = rrset;
        /* up count of new section */
        switch(section) {
                case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
                case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
                default: log_assert(0);
        }
        rrset->section = section;
}

/** see if rrset of type RRSIG contains sig over given type */
static int
rrset_has_sigover(sldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type,
        int* hasother)
{
        int res = 0;
        struct rr_parse* rr = rrset->rr_first;
        log_assert( rrset->type == LDNS_RR_TYPE_RRSIG );
        while(rr) {
                if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type))
                        res = 1;
                else    *hasother = 1;
                rr = rr->next;
        }
        return res;
}

/** move rrsigs from sigset to dataset */
static int
moveover_rrsigs(sldns_buffer* pkt, struct regional* region, 
        struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate)
{
        struct rr_parse* sig = sigset->rr_first;
        struct rr_parse* prev = NULL;
        struct rr_parse* insert;
        struct rr_parse* nextsig;
        while(sig) {
                nextsig = sig->next;
                if(pkt_rrsig_covered_equals(pkt, sig->ttl_data, 
                        dataset->type)) {
                        if(duplicate) {
                                /* new */
                                insert = (struct rr_parse*)regional_alloc(
                                        region, sizeof(struct rr_parse));
                                if(!insert) return 0;
                                insert->outside_packet = 0;
                                insert->ttl_data = sig->ttl_data;
                                insert->size = sig->size;
                                /* prev not used */
                        } else {
                                /* remove from sigset */
                                if(prev) prev->next = sig->next;
                                else    sigset->rr_first = sig->next;
                                if(sigset->rr_last == sig)
                                        sigset->rr_last = prev;
                                sigset->rr_count--;
                                sigset->size -= sig->size;
                                insert = sig;
                                /* prev not changed */
                        }
                        /* add to dataset */
                        dataset->rrsig_count++;
                        insert->next = 0;
                        if(dataset->rrsig_last) 
                                dataset->rrsig_last->next = insert;
                        else    dataset->rrsig_first = insert;
                        dataset->rrsig_last = insert;
                        dataset->size += insert->size;
                } else  {
                        prev = sig;
                }
                sig = nextsig;
        }
        return 1;
}

/** change an rrsig rrset for use as data rrset */
static struct rrset_parse*
change_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg, 
        sldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags,
        int hasother, sldns_pkt_section section, struct regional* region)
{
        struct rrset_parse* dataset = sigset;
        hashvalue_t hash = pkt_hash_rrset(pkt, sigset->dname, datatype, 
                sigset->rrset_class, rrset_flags);
        log_assert( sigset->type == LDNS_RR_TYPE_RRSIG );
        log_assert( datatype != LDNS_RR_TYPE_RRSIG );
        if(hasother) {
                /* need to make new rrset to hold data type */
                dataset = new_rrset(msg, sigset->dname, sigset->dname_len, 
                        datatype, sigset->rrset_class, hash, rrset_flags, 
                        section, region);
                if(!dataset) 
                        return NULL;
                switch(section) {
                        case LDNS_SECTION_ANSWER: msg->an_rrsets++; break;
                        case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
                        case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
                        default: log_assert(0);
                }
                if(!moveover_rrsigs(pkt, region, sigset, dataset, 
                        msg->qtype == LDNS_RR_TYPE_RRSIG ||
                        (msg->qtype == LDNS_RR_TYPE_ANY &&
                        section != LDNS_SECTION_ANSWER) ))
                        return NULL;
                return dataset;
        }
        /* changeover the type of the rrset to data set */
        msgparse_bucket_remove(msg, dataset);
        /* insert into new hash bucket */
        dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)];
        msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset;
        dataset->hash = hash;
        /* use section of data item for result */
        change_section(msg, dataset, section);
        dataset->type = datatype;
        dataset->flags = rrset_flags;
        dataset->rrsig_count += dataset->rr_count;
        dataset->rr_count = 0;
        /* move sigs to end of siglist */
        if(dataset->rrsig_last)
                dataset->rrsig_last->next = dataset->rr_first;
        else    dataset->rrsig_first = dataset->rr_first;
        dataset->rrsig_last = dataset->rr_last;
        dataset->rr_first = 0;
        dataset->rr_last = 0;
        return dataset;
}

/** Find rrset. If equal to previous it is fast. hash if not so.
 * @param msg: the message with hash table.
 * @param pkt: the packet in wireformat (needed for compression ptrs).
 * @param dname: pointer to start of dname (compressed) in packet.
 * @param dnamelen: uncompressed wirefmt length of dname.
 * @param type: type of current rr.
 * @param dclass: class of current rr.
 * @param hash: hash value is returned if the rrset could not be found.
 * @param rrset_flags: is returned if the rrset could not be found.
 * @param prev_dname_first: dname of last seen RR. First seen dname.
 * @param prev_dname_last: dname of last seen RR. Last seen dname.
 * @param prev_dnamelen: dname len of last seen RR.
 * @param prev_type: type of last seen RR.
 * @param prev_dclass: class of last seen RR.
 * @param rrset_prev: last seen RRset.
 * @param section: the current section in the packet.
 * @param region: used to allocate temporary parsing data.
 * @return 0 on out of memory.
 */
static int
find_rrset(struct msg_parse* msg, sldns_buffer* pkt, uint8_t* dname, 
        size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_t* hash, 
        uint32_t* rrset_flags,
        uint8_t** prev_dname_first, uint8_t** prev_dname_last,
        size_t* prev_dnamelen, uint16_t* prev_type,
        uint16_t* prev_dclass, struct rrset_parse** rrset_prev,
        sldns_pkt_section section, struct regional* region)
{
        hashvalue_t dname_h = pkt_hash_rrset_first(pkt, dname);
        uint16_t covtype;
        if(*rrset_prev) {
                /* check if equal to previous item */
                if(type == *prev_type && dclass == *prev_dclass &&
                        dnamelen == *prev_dnamelen &&
                        smart_compare(pkt, dname, *prev_dname_first, 
                                *prev_dname_last) == 0 &&
                        type != LDNS_RR_TYPE_RRSIG) {
                        /* same as previous */
                        *prev_dname_last = dname;
                        return 1;
                }
                /* check if rrsig over previous item */
                if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass &&
                        pkt_rrsig_covered_equals(pkt, sldns_buffer_current(pkt),
                                *prev_type) &&
                        smart_compare(pkt, dname, *prev_dname_first,
                                *prev_dname_last) == 0) {
                        /* covers previous */
                        *prev_dname_last = dname;
                        return 1;
                }
        }
        /* find by hashing and lookup in hashtable */
        *rrset_flags = pkt_rrset_flags(pkt, type, section);
        
        /* if rrsig - try to lookup matching data set first */
        if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt, 
                sldns_buffer_current(pkt), &covtype)) {
                *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 
                        *rrset_flags);
                *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 
                        *rrset_flags, dname, dnamelen, covtype, dclass);
                if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) {
                        /* if NSEC try with NSEC apex bit twiddled */
                        *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
                        *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 
                                *rrset_flags);
                        *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 
                                *hash, *rrset_flags, dname, dnamelen, covtype, 
                                dclass);
                        if(!*rrset_prev) /* untwiddle if not found */
                                *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
                }
                if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) {
                        /* if SOA try with SOA neg flag twiddled */
                        *rrset_flags ^= PACKED_RRSET_SOA_NEG;
                        *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 
                                *rrset_flags);
                        *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 
                                *hash, *rrset_flags, dname, dnamelen, covtype, 
                                dclass);
                        if(!*rrset_prev) /* untwiddle if not found */
                                *rrset_flags ^= PACKED_RRSET_SOA_NEG;
                }
                if(*rrset_prev) {
                        *prev_dname_first = (*rrset_prev)->dname;
                        *prev_dname_last = dname;
                        *prev_dnamelen = dnamelen;
                        *prev_type = covtype;
                        *prev_dclass = dclass;
                        return 1;
                }
        }
        if(type != LDNS_RR_TYPE_RRSIG) {
                int hasother = 0;
                /* find matching rrsig */
                *hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG, 
                        dclass, 0);
                *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 
                        0, dname, dnamelen, LDNS_RR_TYPE_RRSIG, 
                        dclass);
                if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type,
                        &hasother)) {
                        /* yes! */
                        *prev_dname_first = (*rrset_prev)->dname;
                        *prev_dname_last = dname;
                        *prev_dnamelen = dnamelen;
                        *prev_type = type;
                        *prev_dclass = dclass;
                        *rrset_prev = change_rrsig_rrset(*rrset_prev, msg, 
                                pkt, type, *rrset_flags, hasother, section, 
                                region);
                        if(!*rrset_prev) return 0;
                        return 1;
                }
        }

        *hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags);
        *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags, 
                dname, dnamelen, type, dclass);
        if(*rrset_prev)
                *prev_dname_first = (*rrset_prev)->dname;
        else    *prev_dname_first = dname;
        *prev_dname_last = dname;
        *prev_dnamelen = dnamelen;
        *prev_type = type;
        *prev_dclass = dclass;
        return 1;
}

/**
 * Parse query section. 
 * @param pkt: packet, position at call must be at start of query section.
 *      at end position is after query section.
 * @param msg: store results here.
 * @return: 0 if OK, or rcode on error.
 */
static int
parse_query_section(sldns_buffer* pkt, struct msg_parse* msg)
{
        if(msg->qdcount == 0)
                return 0;
        if(msg->qdcount > 1)
                return LDNS_RCODE_FORMERR;
        log_assert(msg->qdcount == 1);
        if(sldns_buffer_remaining(pkt) <= 0)
                return LDNS_RCODE_FORMERR;
        msg->qname = sldns_buffer_current(pkt);
        if((msg->qname_len = pkt_dname_len(pkt)) == 0)
                return LDNS_RCODE_FORMERR;
        if(sldns_buffer_remaining(pkt) < sizeof(uint16_t)*2)
                return LDNS_RCODE_FORMERR;
        msg->qtype = sldns_buffer_read_u16(pkt);
        msg->qclass = sldns_buffer_read_u16(pkt);
        return 0;
}

size_t
get_rdf_size(sldns_rdf_type rdf)
{
        switch(rdf) {
                case LDNS_RDF_TYPE_CLASS:
                case LDNS_RDF_TYPE_ALG:
                case LDNS_RDF_TYPE_INT8:
                        return 1;
                        break;
                case LDNS_RDF_TYPE_INT16:
                case LDNS_RDF_TYPE_TYPE:
                case LDNS_RDF_TYPE_CERT_ALG:
                        return 2;
                        break;
                case LDNS_RDF_TYPE_INT32:
                case LDNS_RDF_TYPE_TIME:
                case LDNS_RDF_TYPE_A:
                case LDNS_RDF_TYPE_PERIOD:
                        return 4;
                        break;
                case LDNS_RDF_TYPE_TSIGTIME:
                        return 6;
                        break;
                case LDNS_RDF_TYPE_AAAA:
                        return 16;
                        break;
                default:
                        log_assert(0); /* add type above */
                        /* only types that appear before a domain  *
                         * name are needed. rest is simply copied. */
        }
        return 0;
}

/** calculate the size of one rr */
static int
calc_size(sldns_buffer* pkt, uint16_t type, struct rr_parse* rr)
{
        const sldns_rr_descriptor* desc;
        uint16_t pkt_len; /* length of rr inside the packet */
        rr->size = sizeof(uint16_t); /* the rdatalen */
        sldns_buffer_skip(pkt, 4); /* skip ttl */
        pkt_len = sldns_buffer_read_u16(pkt);
        if(sldns_buffer_remaining(pkt) < pkt_len)
                return 0;
        desc = sldns_rr_descript(type);
        if(pkt_len > 0 && desc && desc->_dname_count > 0) {
                int count = (int)desc->_dname_count;
                int rdf = 0;
                size_t len;
                size_t oldpos;
                /* skip first part. */
                while(pkt_len > 0 && count) {
                        switch(desc->_wireformat[rdf]) {
                        case LDNS_RDF_TYPE_DNAME:
                                /* decompress every domain name */
                                oldpos = sldns_buffer_position(pkt);
                                if((len = pkt_dname_len(pkt)) == 0)
                                        return 0; /* malformed dname */
                                if(sldns_buffer_position(pkt)-oldpos > pkt_len)
                                        return 0; /* dname exceeds rdata */
                                pkt_len -= sldns_buffer_position(pkt)-oldpos;
                                rr->size += len;
                                count--;
                                len = 0;
                                break;
                        case LDNS_RDF_TYPE_STR:
                                if(pkt_len < 1) {
                                        /* NOTREACHED, due to 'while(>0)' */
                                        return 0; /* len byte exceeds rdata */
                                }
                                len = sldns_buffer_current(pkt)[0] + 1;
                                break;
                        default:
                                len = get_rdf_size(desc->_wireformat[rdf]);
                        }
                        if(len) {
                                if(pkt_len < len)
                                        return 0; /* exceeds rdata */
                                pkt_len -= len;
                                sldns_buffer_skip(pkt, (ssize_t)len);
                                rr->size += len;
                        }
                        rdf++;
                }
        }
        /* remaining rdata */
        rr->size += pkt_len;
        sldns_buffer_skip(pkt, (ssize_t)pkt_len);
        return 1;
}

/** skip rr ttl and rdata */
static int
skip_ttl_rdata(sldns_buffer* pkt) 
{
        uint16_t rdatalen;
        if(sldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
                return 0;
        sldns_buffer_skip(pkt, 4); /* ttl */
        rdatalen = sldns_buffer_read_u16(pkt);
        if(sldns_buffer_remaining(pkt) < rdatalen)
                return 0;
        sldns_buffer_skip(pkt, (ssize_t)rdatalen);
        return 1;
}

/** see if RRSIG is a duplicate of another */
static int
sig_is_double(sldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata)
{
        uint16_t rlen, siglen;
        size_t pos = sldns_buffer_position(pkt);
        struct rr_parse* sig;
        if(sldns_buffer_remaining(pkt) < 6) 
                return 0;
        sldns_buffer_skip(pkt, 4); /* ttl */
        rlen = sldns_buffer_read_u16(pkt);
        if(sldns_buffer_remaining(pkt) < rlen) {
                sldns_buffer_set_position(pkt, pos);
                return 0;
        }
        sldns_buffer_set_position(pkt, pos);

        sig = rrset->rrsig_first;
        while(sig) {
                /* check if rdatalen is same */
                memmove(&siglen, sig->ttl_data+4, sizeof(siglen));
                siglen = ntohs(siglen);
                /* checks if data in packet is exactly the same, this means
                 * also dname in rdata is the same, but rrsig is not allowed
                 * to have compressed dnames anyway. If it is compressed anyway
                 * it will lead to duplicate rrs for qtype=RRSIG. (or ANY).
                 *
                 * Cannot use sig->size because size of the other one is not 
                 * calculated yet.
                 */
                if(siglen == rlen) {
                        if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6, 
                                siglen) == 0) {
                                /* same! */
                                return 1;
                        }
                }
                sig = sig->next;
        }
        return 0;
}

/** Add rr (from packet here) to rrset, skips rr */
static int
add_rr_to_rrset(struct rrset_parse* rrset, sldns_buffer* pkt, 
        struct msg_parse* msg, struct regional* region, 
        sldns_pkt_section section, uint16_t type)
{
        struct rr_parse* rr;
        /* check section of rrset. */
        if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG &&
                rrset->type != LDNS_RR_TYPE_RRSIG) {
                /* silently drop it - we drop the last part, since
                 * trust in rr data depends on the section it is in. 
                 * the less trustworthy part is discarded. 
                 * also the last part is more likely to be incomplete.
                 * RFC 2181: must put RRset only once in response. */
                /*
                verbose(VERB_QUERY, "Packet contains rrset data in "
                        "multiple sections, dropped last part.");
                log_buf(VERB_QUERY, "packet was", pkt);
                */
                /* forwards */
                if(!skip_ttl_rdata(pkt))
                        return LDNS_RCODE_FORMERR;
                return 0;
        } 

        if( (msg->qtype == LDNS_RR_TYPE_RRSIG ||
             msg->qtype == LDNS_RR_TYPE_ANY) 
            && sig_is_double(pkt, rrset, sldns_buffer_current(pkt))) {
                if(!skip_ttl_rdata(pkt))
                        return LDNS_RCODE_FORMERR;
                return 0;
        }
        
        /* create rr */
        if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr))))
                return LDNS_RCODE_SERVFAIL;
        rr->outside_packet = 0;
        rr->ttl_data = sldns_buffer_current(pkt);
        rr->next = 0;
        if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) {
                if(rrset->rrsig_last) 
                        rrset->rrsig_last->next = rr;
                else    rrset->rrsig_first = rr;
                rrset->rrsig_last = rr;
                rrset->rrsig_count++;
        } else {
                if(rrset->rr_last)
                        rrset->rr_last->next = rr;
                else    rrset->rr_first = rr;
                rrset->rr_last = rr;
                rrset->rr_count++;
        }

        /* calc decompressed size */
        if(!calc_size(pkt, type, rr))
                return LDNS_RCODE_FORMERR;
        rrset->size += rr->size;

        return 0;
}

/**
 * Parse packet RR section, for answer, authority and additional sections. 
 * @param pkt: packet, position at call must be at start of section.
 *      at end position is after section.
 * @param msg: store results here.
 * @param region: how to alloc results.
 * @param section: section enum.
 * @param num_rrs: how many rrs are in the section.
 * @param num_rrsets: returns number of rrsets in the section.
 * @return: 0 if OK, or rcode on error.
 */
static int
parse_section(sldns_buffer* pkt, struct msg_parse* msg, 
        struct regional* region, sldns_pkt_section section, 
        uint16_t num_rrs, size_t* num_rrsets)
{
        uint16_t i;
        uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL;
        size_t dnamelen, prev_dnamelen = 0;
        uint16_t type, prev_type = 0;
        uint16_t dclass, prev_dclass = 0;
        uint32_t rrset_flags = 0;
        hashvalue_t hash = 0;
        struct rrset_parse* rrset = NULL;
        int r;

        if(num_rrs == 0)
                return 0;
        if(sldns_buffer_remaining(pkt) <= 0)
                return LDNS_RCODE_FORMERR;
        for(i=0; i<num_rrs; i++) {
                /* parse this RR. */
                dname = sldns_buffer_current(pkt);
                if((dnamelen = pkt_dname_len(pkt)) == 0)
                        return LDNS_RCODE_FORMERR;
                if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */
                        return LDNS_RCODE_FORMERR;
                type = sldns_buffer_read_u16(pkt);
                sldns_buffer_read(pkt, &dclass, sizeof(dclass));

                if(0) { /* debug show what is being parsed. */
                        if(type == LDNS_RR_TYPE_RRSIG) {
                                uint16_t t;
                                if(pkt_rrsig_covered(pkt, 
                                        sldns_buffer_current(pkt), &t))
                                        fprintf(stderr, "parse of %s(%d) [%s(%d)]",
                                        sldns_rr_descript(type)?
                                        sldns_rr_descript(type)->_name: "??",
                                        (int)type,
                                        sldns_rr_descript(t)?
                                        sldns_rr_descript(t)->_name: "??",
                                        (int)t);
                        } else
                          fprintf(stderr, "parse of %s(%d)",
                                sldns_rr_descript(type)?
                                sldns_rr_descript(type)->_name: "??",
                                (int)type);
                        fprintf(stderr, " %s(%d) ",
                                sldns_lookup_by_id(sldns_rr_classes, 
                                (int)ntohs(dclass))?sldns_lookup_by_id(
                                sldns_rr_classes, (int)ntohs(dclass))->name: 
                                "??", (int)ntohs(dclass));
                        dname_print(stderr, pkt, dname);
                        fprintf(stderr, "\n");
                }

                /* see if it is part of an existing RR set */
                if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash, 
                        &rrset_flags, &prev_dname_f, &prev_dname_l, 
                        &prev_dnamelen, &prev_type, &prev_dclass, &rrset, 
                        section, region))
                        return LDNS_RCODE_SERVFAIL;
                if(!rrset) {
                        /* it is a new RR set. hash&flags already calculated.*/
                        (*num_rrsets)++;
                        rrset = new_rrset(msg, dname, dnamelen, type, dclass,
                                hash, rrset_flags, section, region);
                        if(!rrset) 
                                return LDNS_RCODE_SERVFAIL;
                }
                else if(0)      { 
                        fprintf(stderr, "is part of existing: ");
                        dname_print(stderr, pkt, rrset->dname);
                        fprintf(stderr, " type %s(%d)\n",
                                sldns_rr_descript(rrset->type)?
                                sldns_rr_descript(rrset->type)->_name: "??",
                                (int)rrset->type);
                }
                /* add to rrset. */
                if((r=add_rr_to_rrset(rrset, pkt, msg, region, section, 
                        type)) != 0)
                        return r;
        }
        return 0;
}

int
parse_packet(sldns_buffer* pkt, struct msg_parse* msg, struct regional* region)
{
        int ret;
        if(sldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE)
                return LDNS_RCODE_FORMERR;
        /* read the header */
        sldns_buffer_read(pkt, &msg->id, sizeof(uint16_t));
        msg->flags = sldns_buffer_read_u16(pkt);
        msg->qdcount = sldns_buffer_read_u16(pkt);
        msg->ancount = sldns_buffer_read_u16(pkt);
        msg->nscount = sldns_buffer_read_u16(pkt);
        msg->arcount = sldns_buffer_read_u16(pkt);
        if(msg->qdcount > 1)
                return LDNS_RCODE_FORMERR;
        if((ret = parse_query_section(pkt, msg)) != 0)
                return ret;
        if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER,
                msg->ancount, &msg->an_rrsets)) != 0)
                return ret;
        if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY,
                msg->nscount, &msg->ns_rrsets)) != 0)
                return ret;
        if(sldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) {
                /* BIND accepts leniently that an EDNS record is missing.
                 * so, we do too. */
        } else if((ret = parse_section(pkt, msg, region,
                LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0)
                return ret;
        /* if(sldns_buffer_remaining(pkt) > 0) { */
                /* there is spurious data at end of packet. ignore */
        /* } */
        msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets;
        return 0;
}

int 
parse_extract_edns(struct msg_parse* msg, struct edns_data* edns)
{
        struct rrset_parse* rrset = msg->rrset_first;
        struct rrset_parse* prev = 0;
        struct rrset_parse* found = 0;
        struct rrset_parse* found_prev = 0;
        /* since the class encodes the UDP size, we cannot use hash table to
         * find the EDNS OPT record. Scan the packet. */
        while(rrset) {
                if(rrset->type == LDNS_RR_TYPE_OPT) {
                        /* only one OPT RR allowed. */
                        if(found) return LDNS_RCODE_FORMERR;
                        /* found it! */
                        found_prev = prev;
                        found = rrset;
                }
                prev = rrset;
                rrset = rrset->rrset_all_next;
        }
        if(!found) {
                memset(edns, 0, sizeof(*edns));
                edns->udp_size = 512;
                return 0;
        }
        /* check the found RRset */
        /* most lenient check possible. ignore dname, use last opt */
        if(found->section != LDNS_SECTION_ADDITIONAL)
                return LDNS_RCODE_FORMERR; 
        if(found->rr_count == 0)
                return LDNS_RCODE_FORMERR;
        if(0) { /* strict checking of dname and RRcount */
                if(found->dname_len != 1 || !found->dname 
                        || found->dname[0] != 0) return LDNS_RCODE_FORMERR; 
                if(found->rr_count != 1) return LDNS_RCODE_FORMERR; 
        }
        log_assert(found->rr_first && found->rr_last);

        /* remove from packet */
        if(found_prev)  found_prev->rrset_all_next = found->rrset_all_next;
        else    msg->rrset_first = found->rrset_all_next;
        if(found == msg->rrset_last)
                msg->rrset_last = found_prev;
        msg->arcount --;
        msg->ar_rrsets --;
        msg->rrset_count --;
        
        /* take the data ! */
        edns->edns_present = 1;
        edns->ext_rcode = found->rr_last->ttl_data[0];
        edns->edns_version = found->rr_last->ttl_data[1];
        edns->bits = sldns_read_uint16(&found->rr_last->ttl_data[2]);
        edns->udp_size = ntohs(found->rrset_class);
        /* ignore rdata and rrsigs */
        return 0;
}

int 
parse_edns_from_pkt(sldns_buffer* pkt, struct edns_data* edns)
{
        log_assert(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) == 1);
        log_assert(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) == 0);
        log_assert(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) == 0);
        /* check edns section is present */
        if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
                return LDNS_RCODE_FORMERR;
        }
        if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) == 0) {
                memset(edns, 0, sizeof(*edns));
                edns->udp_size = 512;
                return 0;
        }
        /* domain name must be the root of length 1. */
        if(pkt_dname_len(pkt) != 1)
                return LDNS_RCODE_FORMERR;
        if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */
                return LDNS_RCODE_FORMERR;
        if(sldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT)
                return LDNS_RCODE_FORMERR;
        edns->edns_present = 1;
        edns->udp_size = sldns_buffer_read_u16(pkt); /* class is udp size */
        edns->ext_rcode = sldns_buffer_read_u8(pkt); /* ttl used for bits */
        edns->edns_version = sldns_buffer_read_u8(pkt);
        edns->bits = sldns_buffer_read_u16(pkt);
        /* ignore rdata and rrsigs */
        return 0;
}