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"

/** copy and allocate an uncompressed dname. */
static uint8_t*
copy_uncompr(uint8_t* dname, size_t len) 
{
	uint8_t* p = (uint8_t*)malloc(len);
	if(!p) 
		return 0;
	memmove(p, dname, len);
	return p;
}

/** allocate qinfo, return 0 on error. */
static int
parse_create_qinfo(struct msg_parse* msg, struct query_info* qinf)
{
	if(msg->qname) {
		if(!(qinf->qname = copy_uncompr(msg->qname, msg->qname_len)))
			return 0;
	} else	qinf->qname = 0;
	qinf->qnamesize = msg->qname_len;
	qinf->qtype = msg->qtype;
	qinf->qclass = msg->qclass;
	return 1;
}

/** allocate replyinfo, return 0 on error. */
static int
parse_create_repinfo(struct msg_parse* msg, struct reply_info** rep)
{
	/* rrset_count-1 because the first ref is part of the struct. */
	*rep = (struct reply_info*)malloc(sizeof(struct reply_info) + 
		sizeof(struct rrset_ref) * (msg->rrset_count-1)  +
		sizeof(struct ub_packed_rrset_key*) * msg->rrset_count);
	if(!*rep) return 0;
	(*rep)->reply = 0; /* unused */
	(*rep)->replysize = 0; /* unused */
	(*rep)->flags = msg->flags;
	(*rep)->qdcount = msg->qdcount;
	(*rep)->ttl = 0;
	(*rep)->an_numrrsets = msg->an_rrsets;
	(*rep)->ns_numrrsets = msg->ns_rrsets;
	(*rep)->ar_numrrsets = msg->ar_rrsets;
	(*rep)->rrset_count = msg->rrset_count;
	/* array starts after the refs */
	(*rep)->rrsets = (struct ub_packed_rrset_key**)
		&((*rep)->ref[msg->rrset_count]);
	/* zero the arrays to assist cleanup in case of malloc failure */
	memset( (*rep)->rrsets, 0, 
		sizeof(struct ub_packed_rrset_key*) * msg->rrset_count);
	memset( &(*rep)->ref[0], 0, 
		sizeof(struct rrset_ref) * msg->rrset_count);
	return 1;
}

/** allocate (special) rrset keys, return 0 on error. */
static int
parse_alloc_rrset_keys(struct msg_parse* msg, struct reply_info* rep,
	struct alloc_cache* alloc)
{
	size_t i;
	for(i=0; i<msg->rrset_count; i++) {
		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 rrset_parse* pset,
	struct packed_rrset_data* data, uint8_t* to, struct rr_parse* rr)
{
	uint16_t pkt_len;
	uint32_t ttl;
	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 */);
	ttl = ldns_buffer_read_u32(pkt);
	if(ttl < data->ttl)
		data->ttl = 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(ntohs(pset->type));
	if(pkt_len > 0 && 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;
	data->ttl = MAX_TTL;
	data->count = pset->rr_count;
	/* layout: struct - rr_len - rr_data - rdata - rrsig */
	data->rr_len = (size_t*)((uint8_t*)data + 
		sizeof(struct packed_rrset_data));
	data->rr_data = (uint8_t**)&(data->rr_len[data->count]);
	nextrdata = (uint8_t*)&(data->rr_data[data->count]);
	data->rrsig_count = 0;
	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, pset, data, data->rr_data[i], rr))
			return 0;
		rr = rr->next;
	}
	/* if rrsig, its rdata is at nextrdata */
	return 1;
}

/** create rrset return 0 or rcode */
static int
parse_create_rrset(ldns_buffer* pkt, struct rrset_parse* pset,
	struct packed_rrset_data** data)
{
	/* allocate */
	*data = malloc(sizeof(struct packed_rrset_data) + pset->rr_count* 
		(sizeof(size_t)+sizeof(uint8_t*)+sizeof(uint32_t)) + 
		pset->size);
	if(!*data)
		return LDNS_RCODE_SERVFAIL;
	/* copy & decompress */
	if(!parse_rr_copy(pkt, pset, *data))
		return LDNS_RCODE_SERVFAIL;
	return 0;
}

/** 
 * 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.
 * @return 0 or rcode.
 */
static int
parse_copy_decompress(ldns_buffer* pkt, struct msg_parse* msg,
	struct reply_info* rep)
{
	int ret;
	size_t i;
	struct rrset_parse *pset = msg->rrset_first;
	struct packed_rrset_data* data;
	log_assert(rep);

	for(i=0; i<rep->rrset_count; i++) {
		rep->rrsets[i]->rk.flags = pset->flags;
		rep->rrsets[i]->rk.dname_len = pset->dname_len;
		rep->rrsets[i]->rk.dname = (uint8_t*)malloc(
			pset->dname_len + 4 /* size of type and class */ );
		if(!rep->rrsets[i]->rk.dname)
			return LDNS_RCODE_SERVFAIL;
		/** copy & decompress dname */
		dname_pkt_copy(pkt, rep->rrsets[i]->rk.dname, pset->dname);
		/** copy over type and class */
		memmove(&rep->rrsets[i]->rk.dname[pset->dname_len], 
			&pset->type, sizeof(uint16_t));
		memmove(&rep->rrsets[i]->rk.dname[pset->dname_len+2], 
			&pset->rrset_class, sizeof(uint16_t));
		/** read data part. */
		if((ret=parse_create_rrset(pkt, pset, &data)) != 0)
			return ret;
		rep->rrsets[i]->entry.data = (void*)data;
		rep->rrsets[i]->entry.hash = pset->hash;

		pset = pset->rrset_all_next;
	}
	return 0;
}

/** allocate and decompress message and rrsets, returns 0 or rcode. */
static int 
parse_create_msg(ldns_buffer* pkt, struct msg_parse* msg,
	struct alloc_cache* alloc, struct query_info* qinf, 
	struct reply_info** rep)
{
	int ret;
	log_assert(pkt && msg);
	if(!parse_create_qinfo(msg, qinf))
		return LDNS_RCODE_SERVFAIL;
	if(!parse_create_repinfo(msg, rep))
		return LDNS_RCODE_SERVFAIL;
	if(!parse_alloc_rrset_keys(msg, *rep, alloc))
		return LDNS_RCODE_SERVFAIL;
	if((ret=parse_copy_decompress(pkt, msg, *rep)) != 0)
		return ret;
	return 0;
}

int reply_info_parse(ldns_buffer* pkt, struct alloc_cache* alloc,
        struct query_info* qinf, struct reply_info** rep)
{
	/* use scratch pad region-allocator during parsing. */
	region_type* region = region_create(malloc, free);
	struct msg_parse* msg;
	int ret;
	
	qinf->qname = NULL;
	*rep = NULL;
	if(!(msg = region_alloc(region, sizeof(*msg)))) {
		region_free_all(region);
		region_destroy(region);
		return LDNS_RCODE_SERVFAIL;
	}
	memset(msg, 0, sizeof(*msg));
	
	log_assert(ldns_buffer_position(pkt) == 0);
	if((ret = parse_packet(pkt, msg, region)) != 0) {
		region_free_all(region);
		region_destroy(region);
		return ret;
	}

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

	/* exit and cleanup */
	region_free_all(region);
	region_destroy(region);
	return 0;
}

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);
	m->has_cd = (int)LDNS_CD_WIRE(q);
	ldns_buffer_skip(query, LDNS_HEADER_SIZE);
	m->qname = ldns_buffer_current(query);
	if((m->qnamesize = 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->qnamesize))) {
		log_err("query_info_allocqname: out of memory");
		return 0; /* out of memory */
	}
	memcpy(m->qname, q, m->qnamesize);
	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->qnamesize == msg2->qnamesize);
	COMPARE_IT(msg1->has_cd, msg2->has_cd);
	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;
}

void 
reply_info_clear(struct reply_info* m)
{
	free(m->reply);
	m->reply = 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;
	return sizeof(struct msgreply_entry) + sizeof(struct reply_info)
		+ r->replysize + q->qnamesize;
}

void 
query_entry_delete(void *k, void* ATTR_UNUSED(arg))
{
	struct msgreply_entry* q = (struct msgreply_entry*)k;
	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;
	reply_info_clear(r);
	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 = hashlittle(&q->has_cd, sizeof(q->has_cd), h);
	h = dname_query_hash(q->qname, h);
	return h;
}

void 
reply_info_answer(struct reply_info* rep, uint16_t qflags, 
	ldns_buffer* buffer)
{
	uint16_t flags;
	ldns_buffer_clear(buffer);
	ldns_buffer_skip(buffer, 2); /* ID */
	flags = rep->flags | (qflags & BIT_RD); /* copy RD bit */
	log_assert(flags & BIT_QR); /* QR bit must be on in our replies */
	ldns_buffer_write_u16(buffer, flags);
	ldns_buffer_write(buffer, rep->reply, rep->replysize);
	ldns_buffer_flip(buffer);
}

/** store rrset in iov vector */
static int
packed_rrset_iov(struct ub_packed_rrset_key* key, struct iovec* iov, 
	size_t max, uint16_t* num_rrs, uint32_t timenow, region_type* region,
	size_t* used)
{
	size_t i;
	uint32_t* ttl = (uint32_t*)region_alloc(region, sizeof(uint32_t));
	struct packed_rrset_data* data = (struct packed_rrset_data*)
		key->entry.data;
	*num_rrs += data->count;
	if(!ttl) return 0;
	*ttl = htonl(data->ttl - timenow);
	for(i=0; i<data->count; i++) {
		if(max - *used < 3) return 0;
		/* no compression of dnames yet */
		iov[*used].iov_base = (void*)key->rk.dname;
		iov[*used].iov_len = key->rk.dname_len + 4;
		iov[*used+1].iov_base = (void*)ttl;
		iov[*used+1].iov_len = sizeof(uint32_t);
		iov[*used+2].iov_base = (void*)data->rr_data[i];
		iov[*used+2].iov_len = data->rr_len[i];
		*used += 3;
	}

	return 1;
}

/** store msg section in iov vector */
static int
insert_section(struct reply_info* rep, size_t num_rrsets, uint16_t* num_rrs,
	struct iovec* iov, size_t max, size_t rrsets_before,
	uint32_t timenow, region_type* region, size_t* used)
{
	size_t i;
	*num_rrs = 0;
	for(i=0; i<num_rrsets; i++) {
		if(!packed_rrset_iov(rep->rrsets[rrsets_before+i], iov,
			max, num_rrs, timenow, region, used))
			return 0;
	}
	*num_rrs = htons(*num_rrs);
	return 1;
}

size_t reply_info_iov_regen(struct query_info* qinfo, struct reply_info* rep, 
	uint16_t id, uint16_t flags, struct iovec* iov, size_t max, 
	uint32_t timenow, region_type* region)
{
	size_t used;
	uint16_t* hdr = (uint16_t*)region_alloc(region, sizeof(uint16_t)*6);
	if(!hdr) return 0;
	if(max<1) return 0;
	hdr[0] = id;
	hdr[1] = htons(flags);
	iov[0].iov_base = (void*)&hdr[0];
	iov[0].iov_len = sizeof(uint16_t)*6;
	hdr[2] = htons(rep->qdcount);
	used=1;

	/* insert query section */
	if(rep->qdcount) {
		uint16_t* qt = (uint16_t*)region_alloc(region,sizeof(uint16_t));
		uint16_t* qc = (uint16_t*)region_alloc(region,sizeof(uint16_t));
		if(!qt || !qc) return 0;
		if(max-used < 3) return 0;
		iov[used].iov_base = (void*)qinfo->qname;
		iov[used].iov_len = qinfo->qnamesize;
		*qt = htons(qinfo->qtype);
		*qc = htons(qinfo->qclass);
		iov[used+1].iov_base = (void*)qt;
		iov[used+1].iov_len = sizeof(uint16_t);
		iov[used+2].iov_base = (void*)qc;
		iov[used+2].iov_len = sizeof(uint16_t);
		used += 3;
	}

	/* insert answer section */
	if(!insert_section(rep, rep->an_numrrsets, &hdr[3], iov, max, 
		0, timenow, region, &used))
		return 0;

	/* insert auth section */
	if(!insert_section(rep, rep->ns_numrrsets, &hdr[4], iov, max, 
		rep->an_numrrsets, timenow, region, &used))
		return 0;

	/* insert add section */
	if(!insert_section(rep, rep->ar_numrrsets, &hdr[5], iov, max, 
		rep->an_numrrsets + rep->ns_numrrsets, timenow, region, &used))
		return 0;

	return used;
}

void 
reply_info_answer_iov(struct reply_info* rep, uint16_t qid,
        uint16_t qflags, struct comm_reply* comrep, int cached)
{
	/* [0]=reserved for tcplen, [1]=id, [2]=flags, [3]=message */
	struct iovec iov[4];

	iov[1].iov_base = (void*)&qid;
	iov[1].iov_len = sizeof(uint16_t);
	if(!cached) {
		/* original flags, copy RD bit from query. */
		qflags = rep->flags | (qflags & BIT_RD); 
	} else {
		/* remove AA bit, copy RD and CD bits from query. */
		qflags = (rep->flags & ~BIT_AA) | (qflags & (BIT_RD|BIT_CD)); 
	}
	log_assert(qflags & BIT_QR); /* QR bit must be on in our replies */
	qflags = htons(qflags);
	iov[2].iov_base = (void*)&qflags;
	iov[2].iov_len = sizeof(uint16_t);
	iov[3].iov_base = (void*)rep->reply;
	iov[3].iov_len = rep->replysize;
	comm_point_send_reply_iov(comrep, iov, 4);
}

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.qnamesize);
	q->qname = NULL;
	return e;
}