/*
 * query.c
 * - overall query management (allocation, completion)
 * - per-query memory management
 * - query submission and cancellation (user-visible and internal)
 */
/*
 *  This file is
 *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
 *
 *  It is part of adns, which is
 *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
 *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software Foundation,
 *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
 *
 * $Id: query.c,v 1.2 2003/06/14 13:55:50 tr-ircd Exp $
 */

#include "struct.h"
#include "fileio.h"
#include "internal.h"
#include "ircsprintf.h"
#include "memory.h"
#include "s_user.h"

static adns_query query_alloc(adns_state ads, const typeinfo * typei,
			      adns_queryflags flags, struct timeval now)
{
    /* Allocate a virgin query and return it. */
    adns_query qu;

    qu = (adns_query) MyMalloc(sizeof(*qu));
    qu->answer = (adns_answer *) MyMalloc(sizeof(*qu->answer));

    qu->ads = ads;
    qu->state = query_tosend;
    qu->back = qu->next = qu->parent = 0;
    ADNS_LIST_INIT(qu->children);
    LINK_INIT(qu->siblings);
    ADNS_LIST_INIT(qu->allocations);
    qu->interim_allocd = 0;
    qu->preserved_allocd = 0;
    qu->final_allocspace = 0;

    qu->typei = typei;
    qu->query_dgram = 0;
    qu->query_dglen = 0;
    adns__vbuf_init(&qu->vb);

    qu->cname_dgram = 0;
    qu->cname_dglen = qu->cname_begin = 0;

    adns__vbuf_init(&qu->search_vb);
    qu->search_origlen = qu->search_pos = qu->search_doneabs = 0;

    qu->id = -2;		/* will be overwritten with real id before we leave adns */
    qu->flags = flags;
    qu->retries = 0;
    qu->udpnextserver = 0;
    qu->udpsent = 0;
    timerclear(&qu->timeout);
    qu->expires = now.tv_sec + MAXTTLBELIEVE;

    memset(&qu->ctx, 0, sizeof(qu->ctx));

    qu->answer->status = adns_s_ok;
    qu->answer->cname = qu->answer->owner = 0;
    qu->answer->type = typei->type;
    qu->answer->expires = -1;
    qu->answer->nrrs = 0;
    qu->answer->rrs.untyped = 0;
    qu->answer->rrsz = typei->rrsz;

    return qu;
}

static void query_submit(adns_state ads, adns_query qu,
			 const typeinfo * typei, vbuf * qumsg_vb, int id,
			 adns_queryflags flags, struct timeval now)
{
    /* Fills in the query message in for a previously-allocated query,
     * and submits it.  Cannot fail.  Takes over the memory for qumsg_vb.
     */

    qu->vb = *qumsg_vb;
    adns__vbuf_init(qumsg_vb);

    qu->query_dgram = (byte *) MyMalloc(qu->vb.used);

    qu->id = id;
    qu->query_dglen = qu->vb.used;
    memcpy(qu->query_dgram, qu->vb.buf, qu->vb.used);

    adns__query_send(qu, now);
}

adns_status adns__internal_submit(adns_state ads, adns_query * query_r,
				  const typeinfo * typei, vbuf * qumsg_vb,
				  int id, adns_queryflags flags,
				  struct timeval now, const qcontext * ctx)
{
    adns_query qu;

    qu = query_alloc(ads, typei, flags, now);
    if (!qu) {
	adns__vbuf_free(qumsg_vb);
	return adns_s_nomemory;
    }
    *query_r = qu;

    memcpy(&qu->ctx, ctx, sizeof(qu->ctx));
    query_submit(ads, qu, typei, qumsg_vb, id, flags, now);

    return adns_s_ok;
}

static void query_simple(adns_state ads, adns_query qu,
			 const byte * owner, int ol,
			 const typeinfo * typei, adns_queryflags flags, struct timeval now)
{
    vbuf vb_new;
    int id;
    adns_status status;

    status = adns__mkquery(ads, &qu->vb, &id, (const char *) owner, ol, typei, flags);
    if (status) {
	if (status == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
	    adns__search_next(ads, qu, now);
	    return;
	} else {
	    adns__query_fail(qu, status);
	    return;
	}
    }

    vb_new = qu->vb;
    adns__vbuf_init(&qu->vb);
    query_submit(ads, qu, typei, &vb_new, id, flags, now);
}

void adns__search_next(adns_state ads, adns_query qu, struct timeval now)
{
    const char *nextentry;
    adns_status status;

    if (qu->search_doneabs < 0) {
	nextentry = 0;
	qu->search_doneabs = 1;
    } else {
	if (qu->search_pos >= ads->nsearchlist) {
	    if (qu->search_doneabs) {
		status = adns_s_nxdomain;
		goto x_fail;
	    } else {
		nextentry = 0;
		qu->search_doneabs = 1;
	    }
	} else {
	    nextentry = ads->searchlist[qu->search_pos++];
	}
    }

    qu->search_vb.used = qu->search_origlen;
    if (nextentry) {
	if (!adns__vbuf_append(&qu->search_vb, (const byte *) ".", 1) ||
	    !adns__vbuf_appendstr(&qu->search_vb, nextentry)) {
	    status = adns_s_nomemory;
	    goto x_fail;
	}
    }

    MyFree(qu->query_dgram);
    qu->query_dgram = 0;
    qu->query_dglen = 0;

    query_simple(ads, qu, qu->search_vb.buf, qu->search_vb.used, qu->typei, qu->flags, now);
    return;

  x_fail:
    adns__query_fail(qu, status);
}

static int save_owner(adns_query qu, const char *owner, int ol)
{
    /* Returns 1 if OK, otherwise there was no memory. */
    adns_answer *ans;

    ans = qu->answer;
    assert(!ans->owner);

    ans->owner = adns__alloc_preserved(qu, ol + 1);
    if (!ans->owner)
	return 0;

    memcpy(ans->owner, owner, ol);
    ans->owner[ol] = 0;
    return 1;
}

int adns_submit(adns_state ads,
		const char *owner,
		adns_rrtype type, adns_queryflags flags, void *context, adns_query * query_r)
{
    int r, ol, ndots;
    adns_status status;
    const typeinfo *typei;
    struct timeval now;
    adns_query qu;
    const char *p;

    adns__consistency(ads, 0, cc_entex);

    typei = adns__findtype(type);
    if (!typei)
	return ENOSYS;

    r = gettimeofday(&now, 0);
    if (r)
	goto x_errno;
    qu = query_alloc(ads, typei, flags, now);
    if (!qu)
	goto x_errno;

    qu->ctx.ext = context;
    qu->ctx.callback = 0;
    memset(&qu->ctx.info, 0, sizeof(qu->ctx.info));

    *query_r = qu;

    ol = strlen(owner);
    if (!ol) {
	status = adns_s_querydomaininvalid;
	goto x_adnsfail;
    }
    if (ol > DNS_MAXDOMAIN + 1) {
	status = adns_s_querydomaintoolong;
	goto x_adnsfail;
    }

    if (ol >= 1 && owner[ol - 1] == '.' && (ol < 2 || owner[ol - 2] != '\\')) {
	flags &= ~adns_qf_search;
	qu->flags = flags;
	ol--;
    }

    if (flags & adns_qf_search) {
	r = adns__vbuf_append(&qu->search_vb, (const byte *) owner, ol);
	if (!r) {
	    status = adns_s_nomemory;
	    goto x_adnsfail;
	}

	for (ndots = 0, p = owner; (p = strchr(p, '.')); p++, ndots++);
	qu->search_doneabs = (ndots >= ads->searchndots) ? -1 : 0;
	qu->search_origlen = ol;
	adns__search_next(ads, qu, now);
    } else {
	if (flags & adns_qf_owner) {
	    if (!save_owner(qu, owner, ol)) {
		status = adns_s_nomemory;
		goto x_adnsfail;
	    }
	}
	query_simple(ads, qu, (const byte *) owner, ol, typei, flags, now);
    }
    adns__autosys(ads, now);
    adns__consistency(ads, qu, cc_entex);
    return 0;

  x_adnsfail:
    adns__query_fail(qu, status);
    adns__consistency(ads, qu, cc_entex);
    return 0;

  x_errno:
    r = errno;
    assert(r);
    adns__consistency(ads, 0, cc_entex);
    return r;
}

#ifdef IPV6
int adns_submit_reverse_ip6(adns_state ads,
			    const struct sockaddr *addr,
			    const char *zone,
			    adns_rrtype type,
			    adns_queryflags flags, void *context, adns_query * query_r)
{
    char shortbuf[100];
    char *buf, *buf_free;
    const unsigned char *cp;
    char *qp;
    int n, c, lreq, r;

    if (addr->sa_family != AF_INET6)
	return ENOSYS;
    cp = (const unsigned char *) &(((const struct sockaddr_in6 *) addr)->sin6_addr.s6_addr);
    lreq = 71 + strlen(zone) + 1;
    if (lreq > sizeof(shortbuf)) {
	buf = (char *) MyMalloc(strlen(zone) + 4 * 4 + 1);
	if (!buf)
	    return errno;
	buf_free = buf;
    } else {
	buf = shortbuf;
	buf_free = 0;
    }
    qp = buf;
    for (n = 15; n >= 0; n--) {
	c = ircsprintf(qp, "%n.%n.", cp[n] & 0xf, (cp[n] >> 4) & 0xf);
	qp += c;
    }
    strcpy(qp, zone);

    r = adns_submit(ads, buf, type, flags, context, query_r);
    if (buf_free)
	MyFree(buf_free);
    return r;
}
#endif
int adns_submit_reverse_any(adns_state ads,
			    const struct sockaddr *addr,
			    const char *zone,
			    adns_rrtype type,
			    adns_queryflags flags, void *context, adns_query * query_r)
{
    const unsigned char *iaddr;
    char *buf, *buf_free;
    char shortbuf[100];
    int r, lreq;

    flags &= ~adns_qf_search;

    if (addr->sa_family != AF_INET)
	return ENOSYS;
    iaddr = (const unsigned char *) &(((const struct sockaddr_in *) addr)->sin_addr);

    lreq = strlen(zone) + 4 * 4 + 1;
    if (lreq > sizeof(shortbuf)) {
	buf = (char *) MyMalloc(strlen(zone) + 4 * 4 + 1);
#if 0
	if (!buf)
	    return errno;
#endif
	buf_free = buf;
    } else {
	buf = shortbuf;
	buf_free = 0;
    }
    ircsprintf(buf, "%d.%d.%d.%d.%s", iaddr[3], iaddr[2], iaddr[1], iaddr[0], zone);

    r = adns_submit(ads, buf, type, flags, context, query_r);
    MyFree(buf_free);
    return r;
}

int adns_submit_reverse(adns_state ads,
			const struct sockaddr *addr,
			adns_rrtype type,
			adns_queryflags flags, void *context, adns_query * query_r)
{
    if (type != adns_r_ptr && type != adns_r_ptr_raw && type != adns_r_ptr_ip6)
	return EINVAL;
#ifdef IPV6
    if (addr->sa_family == AF_INET6)
	return adns_submit_reverse_ip6(ads, addr, "ip6.int", type, flags, context, query_r);
    else
#endif
	return adns_submit_reverse_any(ads, addr, "in-addr.arpa", type, flags, context, query_r);
}

#if 0
int adns_synchronous(adns_state ads,
		     const char *owner,
		     adns_rrtype type, adns_queryflags flags, adns_answer ** answer_r)
{
    adns_query qu;
    int r;

    r = adns_submit(ads, owner, type, flags, 0, &qu);
    if (r)
	return r;

    r = adns_wait(ads, &qu, answer_r, 0);
    if (r)
	adns_cancel(qu);

    return r;
}
#endif
static void *alloc_common(adns_query qu, size_t sz)
{
allocnode *an;

    if (!sz)
	return qu;		/* Any old pointer will do */
    assert(!qu->final_allocspace);
    an = (allocnode *) MyMalloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
#if 0
    if (!an)
	return 0;
#endif
    LIST_LINK_TAIL(qu->allocations, an);
    return (byte *) an + MEM_ROUND(sizeof(*an));
}

void *adns__alloc_interim(adns_query qu, size_t sz)
{
void *rv;

    sz = MEM_ROUND(sz);
    rv = alloc_common(qu, sz);
    if (!rv)
	return 0;
    qu->interim_allocd += sz;
    return rv;
}

void *adns__alloc_preserved(adns_query qu, size_t sz)
{
void *rv;

    sz = MEM_ROUND(sz);
    rv = adns__alloc_interim(qu, sz);
    if (!rv)
	return 0;
    qu->preserved_allocd += sz;
    return rv;
}

void *adns__alloc_mine(adns_query qu, size_t sz)
{
    return alloc_common(qu, MEM_ROUND(sz));
}

void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz)
{
    allocnode *an;

    if (!block)
	return;
    an = (void *) ((byte *) block - MEM_ROUND(sizeof(*an)));

    assert(!to->final_allocspace);
    assert(!from->final_allocspace);

    LIST_UNLINK(from->allocations, an);
    LIST_LINK_TAIL(to->allocations, an);

    sz = MEM_ROUND(sz);
    from->interim_allocd -= sz;
    to->interim_allocd += sz;

    if (to->expires > from->expires)
	to->expires = from->expires;
}

void *adns__alloc_final(adns_query qu, size_t sz)
{
    /* When we're in the _final stage, we _subtract_ from interim_alloc'd
     * each allocation, and use final_allocspace to point to the next free
     * bit.
     */
void *rp;

    sz = MEM_ROUND(sz);
    rp = qu->final_allocspace;
    assert(rp);
    qu->interim_allocd -= sz;
    assert(qu->interim_allocd >= 0);
    qu->final_allocspace = (byte *) rp + sz;
    return rp;
}

static void cancel_children(adns_query qu)
{
adns_query cqu, ncqu;

    for (cqu = qu->children.head; cqu; cqu = ncqu) {
	ncqu = cqu->siblings.next;
	adns_cancel(cqu);
    }
}

void adns__reset_preserved(adns_query qu)
{
    assert(!qu->final_allocspace);
    cancel_children(qu);
    qu->answer->nrrs = 0;
    qu->answer->rrs.untyped = 0;
    qu->interim_allocd = qu->preserved_allocd;
}

static void free_query_allocs(adns_query qu)
{
allocnode *an, *ann;

    cancel_children(qu);
    for (an = qu->allocations.head; an; an = ann) {
	ann = an->next;
	MyFree(an);
    }
    ADNS_LIST_INIT(qu->allocations);
    adns__vbuf_free(&qu->vb);
    adns__vbuf_free(&qu->search_vb);
    MyFree(qu->query_dgram);
    qu->query_dgram = 0;
}

void adns_cancel(adns_query qu)
{
adns_state ads;

    assert(qu != NULL);
    ads = qu->ads;
    adns__consistency(ads, qu, cc_entex);
    if (qu->parent)
	LIST_UNLINK_PART(qu->parent->children, qu, siblings.);
    switch (qu->state) {
	case query_tosend:
	    LIST_UNLINK(ads->udpw, qu);
	    break;
	case query_tcpw:
	    LIST_UNLINK(ads->tcpw, qu);
	    break;
	case query_childw:
	    LIST_UNLINK(ads->childw, qu);
	    break;
	case query_done:
	    LIST_UNLINK(ads->output, qu);
	    break;
	default:
	    break;
#if 0
	    abort();
#endif
    }
    free_query_allocs(qu);
    MyFree(qu->answer);
    MyFree(qu);
    adns__consistency(ads, 0, cc_entex);
}

void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now)
{
    time_t max;

    assert(ttl <= MAXTTLBELIEVE);
    max = now.tv_sec + ttl;
    if (qu->expires < max)
	return;
    qu->expires = max;
}

static void makefinal_query(adns_query qu)
{
adns_answer *ans;
int rrn;

    ans = qu->answer;

    assert(qu->answer);

    if (qu->interim_allocd) {
	ans =
	    (adns_answer *) MyRealloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
	if (!ans)
	    goto x_nomem;
	qu->answer = ans;
    }

    qu->final_allocspace = (byte *) ans + MEM_ROUND(sizeof(*ans));
    adns__makefinal_str(qu, &ans->cname);
    adns__makefinal_str(qu, &ans->owner);

    if (ans->nrrs) {
	adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs * ans->rrsz);

	for (rrn = 0; rrn < ans->nrrs; rrn++)
	    qu->typei->makefinal(qu, ans->rrs.bytes + rrn * ans->rrsz);
    }

    free_query_allocs(qu);
    return;

  x_nomem:
    qu->preserved_allocd = 0;
    qu->answer->cname = 0;
    qu->answer->owner = 0;
    adns__reset_preserved(qu);	/* (but we just threw away the preserved stuff) */

    qu->answer->status = adns_s_nomemory;
    free_query_allocs(qu);
}

void adns__query_done(adns_query qu)
{
adns_answer *ans;
adns_query parent;

    cancel_children(qu);

    qu->id = -1;
    ans = qu->answer;

    if (qu->flags & adns_qf_owner && qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
	if (!save_owner(qu, (const char *) qu->search_vb.buf, qu->search_vb.used)) {
	    adns__query_fail(qu, adns_s_nomemory);
	    return;
	}
    }

    if (ans->nrrs && qu->typei->diff_needswap) {
	if (!adns__vbuf_ensure(&qu->vb, qu->typei->rrsz)) {
	    adns__query_fail(qu, adns_s_nomemory);
	    return;
	}
	adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
		    qu->vb.buf,
		    (int (*)(void *, const void *, const void *)) qu->typei->
		    diff_needswap, qu->ads);
    }

    ans->expires = qu->expires;
    parent = qu->parent;
    if (parent) {
	LIST_UNLINK_PART(parent->children, qu, siblings.);
	LIST_UNLINK(qu->ads->childw, parent);
	qu->ctx.callback(parent, qu);
	free_query_allocs(qu);
	MyFree(qu->answer);
	MyFree(qu);
    } else {
	makefinal_query(qu);
	LIST_LINK_TAIL(qu->ads->output, qu);
	qu->state = query_done;
    }
}

void adns__query_fail(adns_query qu, adns_status status)
{
    adns__reset_preserved(qu);
    qu->answer->status = status;
    adns__query_done(qu);
}

void adns__makefinal_str(adns_query qu, char **strp)
{
    int l;
    char *before, *after;

    before = *strp;
    if (!before)
	return;
    l = strlen(before) + 1;
    after = adns__alloc_final(qu, l);
    memcpy(after, before, l);
    *strp = after;
}

void adns__makefinal_block(adns_query qu, void **blpp, size_t sz)
{
    void *before, *after;

    before = *blpp;
    if (!before)
	return;
    after = adns__alloc_final(qu, sz);
    memcpy(after, before, sz);
    *blpp = after;
}