unbound/util/data/msgreply.c

/*
 * util/data/msgreply.c - store message and reply data. 
 *
 * 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 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.
 */

/**
 * \file
 *
 * This file contains a data structure to store a message and its reply.
 */

#include "config.h"
#include "util/data/msgreply.h"
#include "util/storage/lookup3.h"
#include "util/log.h"
#include "util/alloc.h"
#include "util/netevent.h"
#include "util/net_help.h"
#include "util/data/dname.h"
#include "util/region-allocator.h"
#include "util/data/msgparse.h"

/** allocate qinfo, return 0 on error. */
static int
parse_create_qinfo(ldns_buffer* pkt, struct msg_parse* msg, 
	struct query_info* qinf, struct region* region)
{
	if(msg->qname) {
		if(region)
			qinf->qname = (uint8_t*)region_alloc(region, 
				msg->qname_len);
		else	qinf->qname = (uint8_t*)malloc(msg->qname_len);
		if(!qinf->qname) return 0;
		dname_pkt_copy(pkt, qinf->qname, msg->qname);
	} else	qinf->qname = 0;
	qinf->qname_len = msg->qname_len;
	qinf->qtype = msg->qtype;
	qinf->qclass = msg->qclass;
	return 1;
}

/** constructor for replyinfo */
static struct reply_info*
construct_reply_info_base(struct region* region, uint16_t flags, size_t qd,
	uint32_t ttl, size_t an, size_t ns, size_t ar, size_t total)
{
	struct reply_info* rep;
	/* rrset_count-1 because the first ref is part of the struct. */
	size_t s = sizeof(struct reply_info) - sizeof(struct rrset_ref) +
		sizeof(struct ub_packed_rrset_key*) * total;
	if(region)
		rep = (struct reply_info*)region_alloc(region, s);
	else	rep = (struct reply_info*)malloc(s + 
			sizeof(struct rrset_ref) * (total));
	if(!rep) 
		return NULL;
	rep->flags = flags;
	rep->qdcount = qd;
	rep->ttl = ttl;
	rep->an_numrrsets = an;
	rep->ns_numrrsets = ns;
	rep->ar_numrrsets = ar;
	rep->rrset_count = total;
	/* array starts after the refs */
	if(region)
		rep->rrsets = (struct ub_packed_rrset_key**)&(rep->ref[0]);
	else	rep->rrsets = (struct ub_packed_rrset_key**)&(rep->ref[total]);
	/* zero the arrays to assist cleanup in case of malloc failure */
	memset( rep->rrsets, 0, sizeof(struct ub_packed_rrset_key*) * total);
	if(!region)
		memset( &rep->ref[0], 0, sizeof(struct rrset_ref) * total);
	return rep;
}

/** allocate replyinfo, return 0 on error. */
static int
parse_create_repinfo(struct msg_parse* msg, struct reply_info** rep,
	struct region* region)
{
	*rep = construct_reply_info_base(region, msg->flags, msg->qdcount, 0,
		msg->an_rrsets, msg->ns_rrsets, msg->ar_rrsets, 
		msg->rrset_count);
	if(!*rep)
		return 0;
	return 1;
}

/** allocate (special) rrset keys, return 0 on error. */
static int
repinfo_alloc_rrset_keys(struct reply_info* rep, struct alloc_cache* alloc, 
	struct region* region)
{
	size_t i;
	for(i=0; i<rep->rrset_count; i++) {
		if(region) {
			rep->rrsets[i] = (struct ub_packed_rrset_key*)
				region_alloc(region, 
				sizeof(struct ub_packed_rrset_key));
			if(rep->rrsets[i]) {
				memset(rep->rrsets[i], 0, 
					sizeof(struct ub_packed_rrset_key));
				rep->rrsets[i]->entry.key = rep->rrsets[i];
			}
		}
		else	rep->rrsets[i] = alloc_special_obtain(alloc);
		if(!rep->rrsets[i])
			return 0;
		rep->rrsets[i]->entry.data = NULL;
	}
	return 1;
}

/** do the rdata copy */
static int
rdata_copy(ldns_buffer* pkt, struct packed_rrset_data* data, uint8_t* to, 
	struct rr_parse* rr, uint32_t* rr_ttl, uint16_t type)
{
	uint16_t pkt_len;
	const ldns_rr_descriptor* desc;
	ldns_buffer_set_position(pkt, (size_t)
		(rr->ttl_data - ldns_buffer_begin(pkt)));
	log_assert(ldns_buffer_remaining(pkt) >= 6 /* ttl + rdatalen */);
	*rr_ttl = ldns_buffer_read_u32(pkt);
	/* RFC 2181 Section 8. if msb of ttl is set treat as if zero. */
	if(*rr_ttl & 0x80000000U)
		*rr_ttl = 0;
	if(*rr_ttl < data->ttl)
		data->ttl = *rr_ttl;
	/* insert decompressed size into rdata len stored in memory */
	/* -2 because rdatalen bytes are not included. */
	pkt_len = htons(rr->size - 2);
	memmove(to, &pkt_len, sizeof(uint16_t));
	to += 2;
	/* read packet rdata len */
	pkt_len = ldns_buffer_read_u16(pkt);
	if(ldns_buffer_remaining(pkt) < pkt_len)
		return 0;
	log_assert((size_t)pkt_len+2 <= rr->size);
	desc = ldns_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;
		/* decompress dnames. */
		while(pkt_len > 0 && count) {
			switch(desc->_wireformat[rdf]) {
			case LDNS_RDF_TYPE_DNAME:
				oldpos = ldns_buffer_position(pkt);
				dname_pkt_copy(pkt, to, 
					ldns_buffer_current(pkt));
				to += pkt_dname_len(pkt);
				pkt_len -= ldns_buffer_position(pkt)-oldpos;
				count--;
				len = 0;
				break;
			case LDNS_RDF_TYPE_STR:
				len = ldns_buffer_current(pkt)[0] + 1;
				break;
			default:
				len = get_rdf_size(desc->_wireformat[rdf]);
				break;
			}
			if(len) {
				memmove(to, ldns_buffer_current(pkt), len);
				to += len;
				ldns_buffer_skip(pkt, (ssize_t)len);
				log_assert(len <= pkt_len);
				pkt_len -= len;
			}
			rdf++;
		}
	}
	/* copy remaining rdata */
	if(pkt_len >  0)
		memmove(to, ldns_buffer_current(pkt), pkt_len);
	
	return 1;
}

/** copy over the data into packed rrset */
static int
parse_rr_copy(ldns_buffer* pkt, struct rrset_parse* pset, 
	struct packed_rrset_data* data)
{
	size_t i;
	struct rr_parse* rr = pset->rr_first;
	uint8_t* nextrdata;
	size_t total = pset->rr_count + pset->rrsig_count;
	data->ttl = MAX_TTL;
	data->count = pset->rr_count;
	data->rrsig_count = pset->rrsig_count;
	data->trust = rrset_trust_none;
	/* layout: struct - rr_len - rr_data - rr_ttl - rdata - rrsig */
	data->rr_len = (size_t*)((uint8_t*)data + 
		sizeof(struct packed_rrset_data));
	data->rr_data = (uint8_t**)&(data->rr_len[total]);
	data->rr_ttl = (uint32_t*)&(data->rr_data[total]);
	nextrdata = (uint8_t*)&(data->rr_ttl[total]);
	for(i=0; i<data->count; i++) {
		data->rr_len[i] = rr->size;
		data->rr_data[i] = nextrdata;
		nextrdata += rr->size;
		if(!rdata_copy(pkt, data, data->rr_data[i], rr, 
			&data->rr_ttl[i], pset->type))
			return 0;
		rr = rr->next;
	}
	/* if rrsig, its rdata is at nextrdata */
	rr = pset->rrsig_first;
	for(i=data->count; i<total; i++) {
		data->rr_len[i] = rr->size;
		data->rr_data[i] = nextrdata;
		nextrdata += rr->size;
		if(!rdata_copy(pkt, data, data->rr_data[i], rr, 
			&data->rr_ttl[i], LDNS_RR_TYPE_RRSIG))
			return 0;
		rr = rr->next;
	}
	return 1;
}

/** create rrset return 0 on failure */
static int
parse_create_rrset(ldns_buffer* pkt, struct rrset_parse* pset,
	struct packed_rrset_data** data, struct region* region)
{
	/* allocate */
	size_t s = sizeof(struct packed_rrset_data) + 
		(pset->rr_count + pset->rrsig_count) * 
		(sizeof(size_t)+sizeof(uint8_t*)+sizeof(uint32_t)) + 
		pset->size;
	if(region)
		*data = region_alloc(region, s);
	else	*data = malloc(s);
	if(!*data)
		return 0;
	/* copy & decompress */
	if(!parse_rr_copy(pkt, pset, *data))
		return 0;
	return 1;
}

/** get trust value for rrset */
static enum rrset_trust
get_rrset_trust(struct reply_info* rep, size_t i)
{
	uint16_t AA = rep->flags & BIT_AA;
	/* TODO: need scrubber that knows what zone the server serves, so that
	 * it can check if AA bit is warranted.
	 * it can check if rrset_trust_nonauth_ans_AA should be used */
	if(i < rep->an_numrrsets) {
		/* answer section */
		if(AA)	return rrset_trust_ans_AA;
		else	return rrset_trust_ans_noAA;
		
	} else if(i < rep->an_numrrsets+rep->ns_numrrsets) {
		/* authority section */
		if(AA)	return rrset_trust_auth_AA;
		else	return rrset_trust_auth_noAA;
	} else {
		/* addit section */
		if(AA)	return rrset_trust_add_AA;
		else	return rrset_trust_add_noAA;
	}
	return rrset_trust_none;
}

/** 
 * Copy and decompress rrs
 * @param pkt: the packet for compression pointer resolution.
 * @param msg: the parsed message
 * @param rep: reply info to put rrs into.
 * @param region: if not NULL, used for allocation.
 * @return 0 on failure.
 */
static int
parse_copy_decompress(ldns_buffer* pkt, struct msg_parse* msg,
	struct reply_info* rep, struct region* region)
{
	size_t i;
	struct rrset_parse *pset = msg->rrset_first;
	struct packed_rrset_data* data;
	log_assert(rep);
	rep->ttl = MAX_TTL;
	if(rep->rrset_count == 0)
		rep->ttl = NORR_TTL;

	for(i=0; i<rep->rrset_count; i++) {
		rep->rrsets[i]->rk.flags = pset->flags;
		rep->rrsets[i]->rk.dname_len = pset->dname_len;
		if(region)
			rep->rrsets[i]->rk.dname = (uint8_t*)region_alloc(
				region, pset->dname_len);
		else	rep->rrsets[i]->rk.dname = 
				(uint8_t*)malloc(pset->dname_len);
		if(!rep->rrsets[i]->rk.dname)
			return 0;
		/** copy & decompress dname */
		dname_pkt_copy(pkt, rep->rrsets[i]->rk.dname, pset->dname);
		/** copy over type and class */
		rep->rrsets[i]->rk.type = htons(pset->type);
		rep->rrsets[i]->rk.rrset_class = pset->rrset_class;
		/** read data part. */
		if(!parse_create_rrset(pkt, pset, &data, region))
			return 0;
		rep->rrsets[i]->entry.data = (void*)data;
		rep->rrsets[i]->entry.key = (void*)rep->rrsets[i];
		rep->rrsets[i]->entry.hash = pset->hash;
		data->trust = get_rrset_trust(rep, i);
		if(data->ttl < rep->ttl)
			rep->ttl = data->ttl;

		pset = pset->rrset_all_next;
	}
	return 1;
}

int 
parse_create_msg(ldns_buffer* pkt, struct msg_parse* msg,
	struct alloc_cache* alloc, struct query_info* qinf, 
	struct reply_info** rep, struct region* region)
{
	log_assert(pkt && msg);
	if(!parse_create_qinfo(pkt, msg, qinf, region))
		return 0;
	if(!parse_create_repinfo(msg, rep, region))
		return 0;
	if(!repinfo_alloc_rrset_keys(*rep, alloc, region))
		return 0;
	if(!parse_copy_decompress(pkt, msg, *rep, region))
		return 0;
	return 1;
}

int reply_info_parse(ldns_buffer* pkt, struct alloc_cache* alloc,
        struct query_info* qinf, struct reply_info** rep, struct region* region,
	struct edns_data* edns)
{
	/* use scratch pad region-allocator during parsing. */
	struct msg_parse* msg;
	int ret;
	
	qinf->qname = NULL;
	*rep = NULL;
	if(!(msg = region_alloc(region, sizeof(*msg)))) {
		return LDNS_RCODE_SERVFAIL;
	}
	memset(msg, 0, sizeof(*msg));
	
	ldns_buffer_set_position(pkt, 0);
	if((ret = parse_packet(pkt, msg, region)) != 0) {
		return ret;
	}
	if((ret = parse_extract_edns(msg, edns)) != 0)
		return ret;

	/* parse OK, allocate return structures */
	/* this also performs dname decompression */
	if(!parse_create_msg(pkt, msg, alloc, qinf, rep, NULL)) {
		query_info_clear(qinf);
		reply_info_parsedelete(*rep, alloc);
		*rep = NULL;
		return LDNS_RCODE_SERVFAIL;
	}
	return 0;
}

/** helper compare function to sort in lock order */
static int
reply_info_sortref_cmp(const void* a, const void* b)
{
	if(a < b) return -1;
	if(a > b) return 1;
	return 0;
}

void 
reply_info_sortref(struct reply_info* rep)
{
	qsort(&rep->ref[0], rep->rrset_count, sizeof(struct rrset_ref),
		reply_info_sortref_cmp);
}

void 
reply_info_set_ttls(struct reply_info* rep, uint32_t timenow)
{
	size_t i, j;
	rep->ttl += timenow;
	for(i=0; i<rep->rrset_count; i++) {
		struct packed_rrset_data* data = (struct packed_rrset_data*)
			rep->ref[i].key->entry.data;
		if(i>0 && rep->ref[i].key == rep->ref[i-1].key)
			continue;
		data->ttl += timenow;
		for(j=0; j<data->count + data->rrsig_count; j++) {
			data->rr_ttl[j] += timenow;
		}
	}
}

void 
reply_info_parsedelete(struct reply_info* rep, struct alloc_cache* alloc)
{
	size_t i;
	if(!rep) 
		return;
	/* no need to lock, since not shared in hashtables. */
	for(i=0; i<rep->rrset_count; i++) {
		ub_packed_rrset_parsedelete(rep->rrsets[i], alloc);
	}
	free(rep);
}

int 
query_info_parse(struct query_info* m, ldns_buffer* query)
{
	uint8_t* q = ldns_buffer_begin(query);
	/* minimum size: header + \0 + qtype + qclass */
	if(ldns_buffer_limit(query) < LDNS_HEADER_SIZE + 5)
		return 0;
	log_assert(!LDNS_QR_WIRE(q));
	log_assert(LDNS_OPCODE_WIRE(q) == LDNS_PACKET_QUERY);
	log_assert(LDNS_QDCOUNT(q) == 1);
	log_assert(ldns_buffer_position(query) == 0);
	ldns_buffer_skip(query, LDNS_HEADER_SIZE);
	m->qname = ldns_buffer_current(query);
	if((m->qname_len = query_dname_len(query)) == 0)
		return 0; /* parse error */
	if(ldns_buffer_remaining(query) < 4)
		return 0; /* need qtype, qclass */
	m->qtype = ldns_buffer_read_u16(query);
	m->qclass = ldns_buffer_read_u16(query);
	return 1;
}

int 
query_info_allocqname(struct query_info* m)
{
	uint8_t* q = m->qname;
	if(!(m->qname = (uint8_t*)malloc(m->qname_len))) {
		log_err("query_info_allocqname: out of memory");
		return 0; /* out of memory */
	}
	memcpy(m->qname, q, m->qname_len);
	return 1;
}

/** tiny subroutine for msgreply_compare */
#define COMPARE_IT(x, y) \
	if( (x) < (y) ) return -1; \
	else if( (x) > (y) ) return +1; \
	log_assert( (x) == (y) );

int 
query_info_compare(void* m1, void* m2)
{
	struct query_info* msg1 = (struct query_info*)m1;
	struct query_info* msg2 = (struct query_info*)m2;
	int mc;
	/* from most different to least different for speed */
	COMPARE_IT(msg1->qtype, msg2->qtype);
	if((mc = query_dname_compare(msg1->qname, msg2->qname)) != 0)
		return mc;
	log_assert(msg1->qname_len == msg2->qname_len);
	COMPARE_IT(msg1->qclass, msg2->qclass);
	return 0;
#undef COMPARE_IT
}

void 
query_info_clear(struct query_info* m)
{
	free(m->qname);
	m->qname = NULL;
}

size_t 
msgreply_sizefunc(void* k, void* d)
{
	struct query_info* q = (struct query_info*)k;
	struct reply_info* r = (struct reply_info*)d;
	size_t s = sizeof(struct msgreply_entry) + sizeof(struct reply_info)
		+ q->qname_len;
	s += (r->rrset_count-1) * sizeof(struct rrset_ref);
	s += r->rrset_count * sizeof(struct ub_packed_rrset_key*);
	return s;
}

void 
query_entry_delete(void *k, void* ATTR_UNUSED(arg), int is_locked)
{
	struct msgreply_entry* q = (struct msgreply_entry*)k;
	if(is_locked) {
		lock_rw_unlock(&q->entry.lock);
	}
	lock_rw_destroy(&q->entry.lock);
	query_info_clear(&q->key);
	free(q);
}

void 
reply_info_delete(void* d, void* ATTR_UNUSED(arg))
{
	struct reply_info* r = (struct reply_info*)d;
	free(r);
}

hashvalue_t 
query_info_hash(struct query_info *q)
{
	hashvalue_t h = 0xab;
	h = hashlittle(&q->qtype, sizeof(q->qtype), h);
	h = hashlittle(&q->qclass, sizeof(q->qclass), h);
	h = dname_query_hash(q->qname, h);
	return h;
}

struct msgreply_entry* 
query_info_entrysetup(struct query_info* q, struct reply_info* r, 
	hashvalue_t h)
{
	struct msgreply_entry* e = (struct msgreply_entry*)malloc( 
		sizeof(struct msgreply_entry));
	if(!e) return NULL;
	memcpy(&e->key, q, sizeof(*q));
	e->entry.hash = h;
	e->entry.key = e;
	e->entry.data = r;
	lock_rw_init(&e->entry.lock);
	lock_protect(&e->entry.lock, &e->key, sizeof(e->key));
	lock_protect(&e->entry.lock, &e->entry.hash, sizeof(e->entry.hash) +
		sizeof(e->entry.key) + sizeof(e->entry.data));
	lock_protect(&e->entry.lock, e->key.qname, e->key.qname_len);
	q->qname = NULL;
	return e;
}

/** copy rrsets from replyinfo to dest replyinfo */
static int
repinfo_copy_rrsets(struct reply_info* dest, struct reply_info* from, 
	struct region* region)
{
	size_t i, s;
	struct packed_rrset_data* fd, *dd;
	struct ub_packed_rrset_key* fk, *dk;
	for(i=0; i<dest->rrset_count; i++) {
		fk = from->rrsets[i];
		dk = dest->rrsets[i];
		fd = (struct packed_rrset_data*)fk->entry.data;
		dk->id = fk->id;
		dk->entry.hash = fk->entry.hash;
		dk->rk = fk->rk;
		if(region)
			dk->rk.dname = (uint8_t*)region_alloc_init(region,
				fk->rk.dname, fk->rk.dname_len);
		else	
			dk->rk.dname = (uint8_t*)memdup(fk->rk.dname, 
				fk->rk.dname_len);
		if(!dk->rk.dname)
			return 0;
		s = packed_rrset_sizeof(fd);
		if(region)
			dd = (struct packed_rrset_data*)region_alloc_init(
				region, fd, s);
		else	dd = (struct packed_rrset_data*)memdup(fd, s);
		if(!dd) 
			return 0;
		packed_rrset_ptr_fixup(dd);
		dk->entry.data = (void*)dd;
	}
	return 1;
}

struct reply_info* 
reply_info_copy(struct reply_info* rep, struct alloc_cache* alloc, 
	struct region* region)
{
	struct reply_info* cp;
	cp = construct_reply_info_base(region, rep->flags, rep->qdcount, 
		rep->ttl, rep->an_numrrsets, rep->ns_numrrsets, 
		rep->ar_numrrsets, rep->rrset_count);
	if(!cp)
		return NULL;
	/* allocate ub_key structures special or not */
	if(!repinfo_alloc_rrset_keys(cp, alloc, region)) {
		if(!region)
			reply_info_parsedelete(cp, alloc);
		return NULL;
	}
	if(!repinfo_copy_rrsets(cp, rep, region)) {
		if(!region)
			reply_info_parsedelete(cp, alloc);
		return NULL;
	}
	return cp;
}

struct ub_packed_rrset_key* 
reply_find_answer_rrset(struct query_info* qinfo, struct reply_info* rep)
{
	uint8_t* sname = qinfo->qname;
	size_t snamelen = qinfo->qname_len;
	size_t i;
	for(i=0; i<rep->an_numrrsets; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		/* first match type, for query of qtype cname */
		if(ntohs(s->rk.type) == qinfo->qtype && 
			ntohs(s->rk.rrset_class) == qinfo->qclass && 
			snamelen == s->rk.dname_len &&
			query_dname_compare(sname, s->rk.dname) == 0) {
			return s;
		}
		/* follow CNAME chain (if any) */
		if(ntohs(s->rk.type) == LDNS_RR_TYPE_CNAME && 
			ntohs(s->rk.rrset_class) == qinfo->qclass && 
			snamelen == s->rk.dname_len &&
			query_dname_compare(sname, s->rk.dname) == 0) {
			get_cname_target(s, &sname, &snamelen);
		}
	}
	return NULL;
}