diff options
Diffstat (limited to 'contrib/unbound/util/data/msgencode.c')
| -rw-r--r-- | contrib/unbound/util/data/msgencode.c | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/contrib/unbound/util/data/msgencode.c b/contrib/unbound/util/data/msgencode.c new file mode 100644 index 0000000..26b5dea --- /dev/null +++ b/contrib/unbound/util/data/msgencode.c @@ -0,0 +1,841 @@ +/* + * util/data/msgencode.c - Encode DNS messages, queries and replies. + * + * 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 a routines to encode DNS messages. + */ + +#include "config.h" +#include "util/data/msgencode.h" +#include "util/data/msgreply.h" +#include "util/data/msgparse.h" +#include "util/data/dname.h" +#include "util/log.h" +#include "util/regional.h" +#include "util/net_help.h" +#include "ldns/sbuffer.h" + +/** return code that means the function ran out of memory. negative so it does + * not conflict with DNS rcodes. */ +#define RETVAL_OUTMEM -2 +/** return code that means the data did not fit (completely) in the packet */ +#define RETVAL_TRUNC -4 +/** return code that means all is peachy keen. Equal to DNS rcode NOERROR */ +#define RETVAL_OK 0 + +/** + * Data structure to help domain name compression in outgoing messages. + * A tree of dnames and their offsets in the packet is kept. + * It is kept sorted, not canonical, but by label at least, so that after + * a lookup of a name you know its closest match, and the parent from that + * closest match. These are possible compression targets. + * + * It is a binary tree, not a rbtree or balanced tree, as the effort + * of keeping it balanced probably outweighs usefulness (given typical + * DNS packet size). + */ +struct compress_tree_node { + /** left node in tree, all smaller to this */ + struct compress_tree_node* left; + /** right node in tree, all larger than this */ + struct compress_tree_node* right; + + /** the parent node - not for tree, but zone parent. One less label */ + struct compress_tree_node* parent; + /** the domain name for this node. Pointer to uncompressed memory. */ + uint8_t* dname; + /** number of labels in domain name, kept to help compare func. */ + int labs; + /** offset in packet that points to this dname */ + size_t offset; +}; + +/** + * Find domain name in tree, returns exact and closest match. + * @param tree: root of tree. + * @param dname: pointer to uncompressed dname. + * @param labs: number of labels in domain name. + * @param match: closest or exact match. + * guaranteed to be smaller or equal to the sought dname. + * can be null if the tree is empty. + * @param matchlabels: number of labels that match with closest match. + * can be zero is there is no match. + * @param insertpt: insert location for dname, if not found. + * @return: 0 if no exact match. + */ +static int +compress_tree_search(struct compress_tree_node** tree, uint8_t* dname, + int labs, struct compress_tree_node** match, int* matchlabels, + struct compress_tree_node*** insertpt) +{ + int c, n, closen=0; + struct compress_tree_node* p = *tree; + struct compress_tree_node* close = 0; + struct compress_tree_node** prev = tree; + while(p) { + if((c = dname_lab_cmp(dname, labs, p->dname, p->labs, &n)) + == 0) { + *matchlabels = n; + *match = p; + return 1; + } + if(c<0) { + prev = &p->left; + p = p->left; + } else { + closen = n; + close = p; /* p->dname is smaller than dname */ + prev = &p->right; + p = p->right; + } + } + *insertpt = prev; + *matchlabels = closen; + *match = close; + return 0; +} + +/** + * Lookup a domain name in compression tree. + * @param tree: root of tree (not the node with '.'). + * @param dname: pointer to uncompressed dname. + * @param labs: number of labels in domain name. + * @param insertpt: insert location for dname, if not found. + * @return: 0 if not found or compress treenode with best compression. + */ +static struct compress_tree_node* +compress_tree_lookup(struct compress_tree_node** tree, uint8_t* dname, + int labs, struct compress_tree_node*** insertpt) +{ + struct compress_tree_node* p; + int m; + if(labs <= 1) + return 0; /* do not compress root node */ + if(compress_tree_search(tree, dname, labs, &p, &m, insertpt)) { + /* exact match */ + return p; + } + /* return some ancestor of p that compresses well. */ + if(m>1) { + /* www.example.com. (labs=4) matched foo.example.com.(labs=4) + * then matchcount = 3. need to go up. */ + while(p && p->labs > m) + p = p->parent; + return p; + } + return 0; +} + +/** + * Create node for domain name compression tree. + * @param dname: pointer to uncompressed dname (stored in tree). + * @param labs: number of labels in dname. + * @param offset: offset into packet for dname. + * @param region: how to allocate memory for new node. + * @return new node or 0 on malloc failure. + */ +static struct compress_tree_node* +compress_tree_newnode(uint8_t* dname, int labs, size_t offset, + struct regional* region) +{ + struct compress_tree_node* n = (struct compress_tree_node*) + regional_alloc(region, sizeof(struct compress_tree_node)); + if(!n) return 0; + n->left = 0; + n->right = 0; + n->parent = 0; + n->dname = dname; + n->labs = labs; + n->offset = offset; + return n; +} + +/** + * Store domain name and ancestors into compression tree. + * @param dname: pointer to uncompressed dname (stored in tree). + * @param labs: number of labels in dname. + * @param offset: offset into packet for dname. + * @param region: how to allocate memory for new node. + * @param closest: match from previous lookup, used to compress dname. + * may be NULL if no previous match. + * if the tree has an ancestor of dname already, this must be it. + * @param insertpt: where to insert the dname in tree. + * @return: 0 on memory error. + */ +static int +compress_tree_store(uint8_t* dname, int labs, size_t offset, + struct regional* region, struct compress_tree_node* closest, + struct compress_tree_node** insertpt) +{ + uint8_t lablen; + struct compress_tree_node* newnode; + struct compress_tree_node* prevnode = NULL; + int uplabs = labs-1; /* does not store root in tree */ + if(closest) uplabs = labs - closest->labs; + log_assert(uplabs >= 0); + /* algorithms builds up a vine of dname-labels to hang into tree */ + while(uplabs--) { + if(offset > PTR_MAX_OFFSET) { + /* insertion failed, drop vine */ + return 1; /* compression pointer no longer useful */ + } + if(!(newnode = compress_tree_newnode(dname, labs, offset, + region))) { + /* insertion failed, drop vine */ + return 0; + } + + if(prevnode) { + /* chain nodes together, last one has one label more, + * so is larger than newnode, thus goes right. */ + newnode->right = prevnode; + prevnode->parent = newnode; + } + + /* next label */ + lablen = *dname++; + dname += lablen; + offset += lablen+1; + prevnode = newnode; + labs--; + } + /* if we have a vine, hang the vine into the tree */ + if(prevnode) { + *insertpt = prevnode; + prevnode->parent = closest; + } + return 1; +} + +/** compress a domain name */ +static int +write_compressed_dname(sldns_buffer* pkt, uint8_t* dname, int labs, + struct compress_tree_node* p) +{ + /* compress it */ + int labcopy = labs - p->labs; + uint8_t lablen; + uint16_t ptr; + + if(labs == 1) { + /* write root label */ + if(sldns_buffer_remaining(pkt) < 1) + return 0; + sldns_buffer_write_u8(pkt, 0); + return 1; + } + + /* copy the first couple of labels */ + while(labcopy--) { + lablen = *dname++; + if(sldns_buffer_remaining(pkt) < (size_t)lablen+1) + return 0; + sldns_buffer_write_u8(pkt, lablen); + sldns_buffer_write(pkt, dname, lablen); + dname += lablen; + } + /* insert compression ptr */ + if(sldns_buffer_remaining(pkt) < 2) + return 0; + ptr = PTR_CREATE(p->offset); + sldns_buffer_write_u16(pkt, ptr); + return 1; +} + +/** compress owner name of RR, return RETVAL_OUTMEM RETVAL_TRUNC */ +static int +compress_owner(struct ub_packed_rrset_key* key, sldns_buffer* pkt, + struct regional* region, struct compress_tree_node** tree, + size_t owner_pos, uint16_t* owner_ptr, int owner_labs) +{ + struct compress_tree_node* p; + struct compress_tree_node** insertpt; + if(!*owner_ptr) { + /* compress first time dname */ + if((p = compress_tree_lookup(tree, key->rk.dname, + owner_labs, &insertpt))) { + if(p->labs == owner_labs) + /* avoid ptr chains, since some software is + * not capable of decoding ptr after a ptr. */ + *owner_ptr = htons(PTR_CREATE(p->offset)); + if(!write_compressed_dname(pkt, key->rk.dname, + owner_labs, p)) + return RETVAL_TRUNC; + /* check if typeclass+4 ttl + rdatalen is available */ + if(sldns_buffer_remaining(pkt) < 4+4+2) + return RETVAL_TRUNC; + } else { + /* no compress */ + if(sldns_buffer_remaining(pkt) < key->rk.dname_len+4+4+2) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, key->rk.dname, + key->rk.dname_len); + if(owner_pos <= PTR_MAX_OFFSET) + *owner_ptr = htons(PTR_CREATE(owner_pos)); + } + if(!compress_tree_store(key->rk.dname, owner_labs, + owner_pos, region, p, insertpt)) + return RETVAL_OUTMEM; + } else { + /* always compress 2nd-further RRs in RRset */ + if(owner_labs == 1) { + if(sldns_buffer_remaining(pkt) < 1+4+4+2) + return RETVAL_TRUNC; + sldns_buffer_write_u8(pkt, 0); + } else { + if(sldns_buffer_remaining(pkt) < 2+4+4+2) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, owner_ptr, 2); + } + } + return RETVAL_OK; +} + +/** compress any domain name to the packet, return RETVAL_* */ +static int +compress_any_dname(uint8_t* dname, sldns_buffer* pkt, int labs, + struct regional* region, struct compress_tree_node** tree) +{ + struct compress_tree_node* p; + struct compress_tree_node** insertpt = NULL; + size_t pos = sldns_buffer_position(pkt); + if((p = compress_tree_lookup(tree, dname, labs, &insertpt))) { + if(!write_compressed_dname(pkt, dname, labs, p)) + return RETVAL_TRUNC; + } else { + if(!dname_buffer_write(pkt, dname)) + return RETVAL_TRUNC; + } + if(!compress_tree_store(dname, labs, pos, region, p, insertpt)) + return RETVAL_OUTMEM; + return RETVAL_OK; +} + +/** return true if type needs domain name compression in rdata */ +static const sldns_rr_descriptor* +type_rdata_compressable(struct ub_packed_rrset_key* key) +{ + uint16_t t = ntohs(key->rk.type); + if(sldns_rr_descript(t) && + sldns_rr_descript(t)->_compress == LDNS_RR_COMPRESS) + return sldns_rr_descript(t); + return 0; +} + +/** compress domain names in rdata, return RETVAL_* */ +static int +compress_rdata(sldns_buffer* pkt, uint8_t* rdata, size_t todolen, + struct regional* region, struct compress_tree_node** tree, + const sldns_rr_descriptor* desc) +{ + int labs, r, rdf = 0; + size_t dname_len, len, pos = sldns_buffer_position(pkt); + uint8_t count = desc->_dname_count; + + sldns_buffer_skip(pkt, 2); /* rdata len fill in later */ + /* space for rdatalen checked for already */ + rdata += 2; + todolen -= 2; + while(todolen > 0 && count) { + switch(desc->_wireformat[rdf]) { + case LDNS_RDF_TYPE_DNAME: + labs = dname_count_size_labels(rdata, &dname_len); + if((r=compress_any_dname(rdata, pkt, labs, region, + tree)) != RETVAL_OK) + return r; + rdata += dname_len; + todolen -= dname_len; + count--; + len = 0; + break; + case LDNS_RDF_TYPE_STR: + len = *rdata + 1; + break; + default: + len = get_rdf_size(desc->_wireformat[rdf]); + } + if(len) { + /* copy over */ + if(sldns_buffer_remaining(pkt) < len) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, rdata, len); + todolen -= len; + rdata += len; + } + rdf++; + } + /* copy remainder */ + if(todolen > 0) { + if(sldns_buffer_remaining(pkt) < todolen) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, rdata, todolen); + } + + /* set rdata len */ + sldns_buffer_write_u16_at(pkt, pos, sldns_buffer_position(pkt)-pos-2); + return RETVAL_OK; +} + +/** Returns true if RR type should be included */ +static int +rrset_belongs_in_reply(sldns_pkt_section s, uint16_t rrtype, uint16_t qtype, + int dnssec) +{ + if(dnssec) + return 1; + /* skip non DNSSEC types, except if directly queried for */ + if(s == LDNS_SECTION_ANSWER) { + if(qtype == LDNS_RR_TYPE_ANY || qtype == rrtype) + return 1; + } + /* check DNSSEC-ness */ + switch(rrtype) { + case LDNS_RR_TYPE_SIG: + case LDNS_RR_TYPE_KEY: + case LDNS_RR_TYPE_NXT: + case LDNS_RR_TYPE_DS: + case LDNS_RR_TYPE_RRSIG: + case LDNS_RR_TYPE_NSEC: + case LDNS_RR_TYPE_DNSKEY: + case LDNS_RR_TYPE_NSEC3: + case LDNS_RR_TYPE_NSEC3PARAMS: + return 0; + } + return 1; +} + +/** store rrset in buffer in wireformat, return RETVAL_* */ +static int +packed_rrset_encode(struct ub_packed_rrset_key* key, sldns_buffer* pkt, + uint16_t* num_rrs, time_t timenow, struct regional* region, + int do_data, int do_sig, struct compress_tree_node** tree, + sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset) +{ + size_t i, j, owner_pos; + int r, owner_labs; + uint16_t owner_ptr = 0; + struct packed_rrset_data* data = (struct packed_rrset_data*) + key->entry.data; + + /* does this RR type belong in the answer? */ + if(!rrset_belongs_in_reply(s, ntohs(key->rk.type), qtype, dnssec)) + return RETVAL_OK; + + owner_labs = dname_count_labels(key->rk.dname); + owner_pos = sldns_buffer_position(pkt); + + if(do_data) { + const sldns_rr_descriptor* c = type_rdata_compressable(key); + for(i=0; i<data->count; i++) { + /* rrset roundrobin */ + j = (i + rr_offset) % data->count; + if((r=compress_owner(key, pkt, region, tree, + owner_pos, &owner_ptr, owner_labs)) + != RETVAL_OK) + return r; + sldns_buffer_write(pkt, &key->rk.type, 2); + sldns_buffer_write(pkt, &key->rk.rrset_class, 2); + if(data->rr_ttl[j] < timenow) + sldns_buffer_write_u32(pkt, 0); + else sldns_buffer_write_u32(pkt, + data->rr_ttl[j]-timenow); + if(c) { + if((r=compress_rdata(pkt, data->rr_data[j], + data->rr_len[j], region, tree, c)) + != RETVAL_OK) + return r; + } else { + if(sldns_buffer_remaining(pkt) < data->rr_len[j]) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, data->rr_data[j], + data->rr_len[j]); + } + } + } + /* insert rrsigs */ + if(do_sig && dnssec) { + size_t total = data->count+data->rrsig_count; + for(i=data->count; i<total; i++) { + if(owner_ptr && owner_labs != 1) { + if(sldns_buffer_remaining(pkt) < + 2+4+4+data->rr_len[i]) + return RETVAL_TRUNC; + sldns_buffer_write(pkt, &owner_ptr, 2); + } else { + if((r=compress_any_dname(key->rk.dname, + pkt, owner_labs, region, tree)) + != RETVAL_OK) + return r; + if(sldns_buffer_remaining(pkt) < + 4+4+data->rr_len[i]) + return RETVAL_TRUNC; + } + sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_RRSIG); + sldns_buffer_write(pkt, &key->rk.rrset_class, 2); + if(data->rr_ttl[i] < timenow) + sldns_buffer_write_u32(pkt, 0); + else sldns_buffer_write_u32(pkt, + data->rr_ttl[i]-timenow); + /* rrsig rdata cannot be compressed, perform 100+ byte + * memcopy. */ + sldns_buffer_write(pkt, data->rr_data[i], + data->rr_len[i]); + } + } + /* change rrnum only after we are sure it fits */ + if(do_data) + *num_rrs += data->count; + if(do_sig && dnssec) + *num_rrs += data->rrsig_count; + + return RETVAL_OK; +} + +/** store msg section in wireformat buffer, return RETVAL_* */ +static int +insert_section(struct reply_info* rep, size_t num_rrsets, uint16_t* num_rrs, + sldns_buffer* pkt, size_t rrsets_before, time_t timenow, + struct regional* region, struct compress_tree_node** tree, + sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset) +{ + int r; + size_t i, setstart; + *num_rrs = 0; + if(s != LDNS_SECTION_ADDITIONAL) { + if(s == LDNS_SECTION_ANSWER && qtype == LDNS_RR_TYPE_ANY) + dnssec = 1; /* include all types in ANY answer */ + for(i=0; i<num_rrsets; i++) { + setstart = sldns_buffer_position(pkt); + if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i], + pkt, num_rrs, timenow, region, 1, 1, tree, + s, qtype, dnssec, rr_offset)) + != RETVAL_OK) { + /* Bad, but if due to size must set TC bit */ + /* trim off the rrset neatly. */ + sldns_buffer_set_position(pkt, setstart); + return r; + } + } + } else { + for(i=0; i<num_rrsets; i++) { + setstart = sldns_buffer_position(pkt); + if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i], + pkt, num_rrs, timenow, region, 1, 0, tree, + s, qtype, dnssec, rr_offset)) + != RETVAL_OK) { + sldns_buffer_set_position(pkt, setstart); + return r; + } + } + if(dnssec) + for(i=0; i<num_rrsets; i++) { + setstart = sldns_buffer_position(pkt); + if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i], + pkt, num_rrs, timenow, region, 0, 1, tree, + s, qtype, dnssec, rr_offset)) + != RETVAL_OK) { + sldns_buffer_set_position(pkt, setstart); + return r; + } + } + } + return RETVAL_OK; +} + +/** store query section in wireformat buffer, return RETVAL */ +static int +insert_query(struct query_info* qinfo, struct compress_tree_node** tree, + sldns_buffer* buffer, struct regional* region) +{ + if(sldns_buffer_remaining(buffer) < + qinfo->qname_len+sizeof(uint16_t)*2) + return RETVAL_TRUNC; /* buffer too small */ + /* the query is the first name inserted into the tree */ + if(!compress_tree_store(qinfo->qname, + dname_count_labels(qinfo->qname), + sldns_buffer_position(buffer), region, NULL, tree)) + return RETVAL_OUTMEM; + if(sldns_buffer_current(buffer) == qinfo->qname) + sldns_buffer_skip(buffer, (ssize_t)qinfo->qname_len); + else sldns_buffer_write(buffer, qinfo->qname, qinfo->qname_len); + sldns_buffer_write_u16(buffer, qinfo->qtype); + sldns_buffer_write_u16(buffer, qinfo->qclass); + return RETVAL_OK; +} + +static int +positive_answer(struct reply_info* rep, uint16_t qtype) { + size_t i; + if (FLAGS_GET_RCODE(rep->flags) != LDNS_RCODE_NOERROR) + return 0; + + for(i=0;i<rep->an_numrrsets; i++) { + if(ntohs(rep->rrsets[i]->rk.type) == qtype) { + /* in case it is a wildcard with DNSSEC, there will + * be NSEC/NSEC3 records in the authority section + * that we cannot remove */ + for(i=rep->an_numrrsets; i<rep->an_numrrsets+ + rep->ns_numrrsets; i++) { + if(ntohs(rep->rrsets[i]->rk.type) == + LDNS_RR_TYPE_NSEC || + ntohs(rep->rrsets[i]->rk.type) == + LDNS_RR_TYPE_NSEC3) + return 0; + } + return 1; + } + } + return 0; +} + +int +reply_info_encode(struct query_info* qinfo, struct reply_info* rep, + uint16_t id, uint16_t flags, sldns_buffer* buffer, time_t timenow, + struct regional* region, uint16_t udpsize, int dnssec) +{ + uint16_t ancount=0, nscount=0, arcount=0; + struct compress_tree_node* tree = 0; + int r; + size_t rr_offset; + + sldns_buffer_clear(buffer); + if(udpsize < sldns_buffer_limit(buffer)) + sldns_buffer_set_limit(buffer, udpsize); + if(sldns_buffer_remaining(buffer) < LDNS_HEADER_SIZE) + return 0; + + sldns_buffer_write(buffer, &id, sizeof(uint16_t)); + sldns_buffer_write_u16(buffer, flags); + sldns_buffer_write_u16(buffer, rep->qdcount); + /* set an, ns, ar counts to zero in case of small packets */ + sldns_buffer_write(buffer, "\000\000\000\000\000\000", 6); + + /* insert query section */ + if(rep->qdcount) { + if((r=insert_query(qinfo, &tree, buffer, region)) != + RETVAL_OK) { + if(r == RETVAL_TRUNC) { + /* create truncated message */ + sldns_buffer_write_u16_at(buffer, 4, 0); + LDNS_TC_SET(sldns_buffer_begin(buffer)); + sldns_buffer_flip(buffer); + return 1; + } + return 0; + } + } + /* roundrobin offset. using query id for random number. With ntohs + * for different roundrobins for sequential id client senders. */ + rr_offset = RRSET_ROUNDROBIN?ntohs(id):0; + + /* insert answer section */ + if((r=insert_section(rep, rep->an_numrrsets, &ancount, buffer, + 0, timenow, region, &tree, LDNS_SECTION_ANSWER, qinfo->qtype, + dnssec, rr_offset)) != RETVAL_OK) { + if(r == RETVAL_TRUNC) { + /* create truncated message */ + sldns_buffer_write_u16_at(buffer, 6, ancount); + LDNS_TC_SET(sldns_buffer_begin(buffer)); + sldns_buffer_flip(buffer); + return 1; + } + return 0; + } + sldns_buffer_write_u16_at(buffer, 6, ancount); + + /* if response is positive answer, auth/add sections are not required */ + if( ! (MINIMAL_RESPONSES && positive_answer(rep, qinfo->qtype)) ) { + /* insert auth section */ + if((r=insert_section(rep, rep->ns_numrrsets, &nscount, buffer, + rep->an_numrrsets, timenow, region, &tree, + LDNS_SECTION_AUTHORITY, qinfo->qtype, + dnssec, rr_offset)) != RETVAL_OK) { + if(r == RETVAL_TRUNC) { + /* create truncated message */ + sldns_buffer_write_u16_at(buffer, 8, nscount); + LDNS_TC_SET(sldns_buffer_begin(buffer)); + sldns_buffer_flip(buffer); + return 1; + } + return 0; + } + sldns_buffer_write_u16_at(buffer, 8, nscount); + + /* insert add section */ + if((r=insert_section(rep, rep->ar_numrrsets, &arcount, buffer, + rep->an_numrrsets + rep->ns_numrrsets, timenow, region, + &tree, LDNS_SECTION_ADDITIONAL, qinfo->qtype, + dnssec, rr_offset)) != RETVAL_OK) { + if(r == RETVAL_TRUNC) { + /* no need to set TC bit, this is the additional */ + sldns_buffer_write_u16_at(buffer, 10, arcount); + sldns_buffer_flip(buffer); + return 1; + } + return 0; + } + sldns_buffer_write_u16_at(buffer, 10, arcount); + } + sldns_buffer_flip(buffer); + return 1; +} + +uint16_t +calc_edns_field_size(struct edns_data* edns) +{ + if(!edns || !edns->edns_present) + return 0; + /* domain root '.' + type + class + ttl + rdatalen(=0) */ + return 1 + 2 + 2 + 4 + 2; +} + +void +attach_edns_record(sldns_buffer* pkt, struct edns_data* edns) +{ + size_t len; + if(!edns || !edns->edns_present) + return; + /* inc additional count */ + sldns_buffer_write_u16_at(pkt, 10, + sldns_buffer_read_u16_at(pkt, 10) + 1); + len = sldns_buffer_limit(pkt); + sldns_buffer_clear(pkt); + sldns_buffer_set_position(pkt, len); + /* write EDNS record */ + sldns_buffer_write_u8(pkt, 0); /* '.' label */ + sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_OPT); /* type */ + sldns_buffer_write_u16(pkt, edns->udp_size); /* class */ + sldns_buffer_write_u8(pkt, edns->ext_rcode); /* ttl */ + sldns_buffer_write_u8(pkt, edns->edns_version); + sldns_buffer_write_u16(pkt, edns->bits); + sldns_buffer_write_u16(pkt, 0); /* rdatalen */ + sldns_buffer_flip(pkt); +} + +int +reply_info_answer_encode(struct query_info* qinf, struct reply_info* rep, + uint16_t id, uint16_t qflags, sldns_buffer* pkt, time_t timenow, + int cached, struct regional* region, uint16_t udpsize, + struct edns_data* edns, int dnssec, int secure) +{ + uint16_t flags; + int attach_edns = 1; + + if(!cached || rep->authoritative) { + /* original flags, copy RD and CD bits from query. */ + flags = rep->flags | (qflags & (BIT_RD|BIT_CD)); + } else { + /* remove AA bit, copy RD and CD bits from query. */ + flags = (rep->flags & ~BIT_AA) | (qflags & (BIT_RD|BIT_CD)); + } + if(secure && (dnssec || (qflags&BIT_AD))) + flags |= BIT_AD; + log_assert(flags & BIT_QR); /* QR bit must be on in our replies */ + if(udpsize < LDNS_HEADER_SIZE) + return 0; + if(udpsize < LDNS_HEADER_SIZE + calc_edns_field_size(edns)) { + /* packet too small to contain edns, omit it. */ + attach_edns = 0; + } else { + /* reserve space for edns record */ + udpsize -= calc_edns_field_size(edns); + } + + if(!reply_info_encode(qinf, rep, id, flags, pkt, timenow, region, + udpsize, dnssec)) { + log_err("reply encode: out of memory"); + return 0; + } + if(attach_edns) + attach_edns_record(pkt, edns); + return 1; +} + +void +qinfo_query_encode(sldns_buffer* pkt, struct query_info* qinfo) +{ + uint16_t flags = 0; /* QUERY, NOERROR */ + sldns_buffer_clear(pkt); + log_assert(sldns_buffer_remaining(pkt) >= 12+255+4/*max query*/); + sldns_buffer_skip(pkt, 2); /* id done later */ + sldns_buffer_write_u16(pkt, flags); + sldns_buffer_write_u16(pkt, 1); /* query count */ + sldns_buffer_write(pkt, "\000\000\000\000\000\000", 6); /* counts */ + sldns_buffer_write(pkt, qinfo->qname, qinfo->qname_len); + sldns_buffer_write_u16(pkt, qinfo->qtype); + sldns_buffer_write_u16(pkt, qinfo->qclass); + sldns_buffer_flip(pkt); +} + +void +error_encode(sldns_buffer* buf, int r, struct query_info* qinfo, + uint16_t qid, uint16_t qflags, struct edns_data* edns) +{ + uint16_t flags; + + sldns_buffer_clear(buf); + sldns_buffer_write(buf, &qid, sizeof(uint16_t)); + flags = (uint16_t)(BIT_QR | BIT_RA | r); /* QR and retcode*/ + flags |= (qflags & (BIT_RD|BIT_CD)); /* copy RD and CD bit */ + sldns_buffer_write_u16(buf, flags); + if(qinfo) flags = 1; + else flags = 0; + sldns_buffer_write_u16(buf, flags); + flags = 0; + sldns_buffer_write(buf, &flags, sizeof(uint16_t)); + sldns_buffer_write(buf, &flags, sizeof(uint16_t)); + sldns_buffer_write(buf, &flags, sizeof(uint16_t)); + if(qinfo) { + if(sldns_buffer_current(buf) == qinfo->qname) + sldns_buffer_skip(buf, (ssize_t)qinfo->qname_len); + else sldns_buffer_write(buf, qinfo->qname, qinfo->qname_len); + sldns_buffer_write_u16(buf, qinfo->qtype); + sldns_buffer_write_u16(buf, qinfo->qclass); + } + sldns_buffer_flip(buf); + if(edns) { + struct edns_data es = *edns; + es.edns_version = EDNS_ADVERTISED_VERSION; + es.udp_size = EDNS_ADVERTISED_SIZE; + es.ext_rcode = 0; + es.bits &= EDNS_DO; + if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) > + edns->udp_size) + return; + attach_edns_record(buf, &es); + } +} |
