/*      $OpenBSD: res_mkquery.c,v 1.3 2022/01/20 14:18:10 naddy Exp $   */
/*
 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>

#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <inttypes.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "common.h"

/* in asr.c but we don't want them exposed right now */
static void dump_packet(const void *, size_t);

static char *print_query(struct query *, char *, size_t);
static char *print_rr(struct rr *, char *, size_t);
static char *print_host(const struct sockaddr *, char *, size_t);
static char* print_dname(const char *, char *, size_t);


static void
usage(void)
{
        extern const char * __progname;

        fprintf(stderr, "usage: %s [-deq] [-t type] [host...]\n",
            __progname);
        exit(1);
}

int
main(int argc, char *argv[])
{
        int                      ch, i, r;
        uint16_t                 type = T_A;
        char                     buf[1024], *host;

        while((ch = getopt(argc, argv, "R:et:")) !=  -1) {
                switch(ch) {
                case 'R':
                        parseresopt(optarg);
                        break;
                case 'e':
                        long_err += 1;
                        break;
                case 't':
                        if ((type = strtotype(optarg)) == 0)
                                usage();
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        }
        argc -= optind;
        argv += optind;

        for (i = 0; i < argc; i++) {

                if (i)
                        printf("\n");

                printf("===> \"%s\"\n", argv[i]);
                host = gethostarg(argv[i]);

                errno = 0;
                h_errno = 0;
                gai_errno = 0;
                rrset_errno = 0;

                r = res_mkquery(QUERY, host, C_IN, type, NULL, 0, NULL, buf, sizeof(buf));
                if (r != -1) {
                        dump_packet(buf, r);
                        printf(";; MSG SIZE %i\n", r);
                }
                print_errors();
        }

        return (0);
}

#define OPCODE_SHIFT    11
#define Z_SHIFT         4

static char*
print_header(struct header *h, char *buf, size_t max)
{
        snprintf(buf, max,
        "id:0x.... %s op:%i %s %s %s %s z:%i r:%s qd:%i an:%i ns:%i ar:%i",
            (h->flags & QR_MASK) ? "QR":"  ",
            (int)(OPCODE(h->flags) >> OPCODE_SHIFT),
            (h->flags & AA_MASK) ? "AA":"  ",
            (h->flags & TC_MASK) ? "TC":"  ",
            (h->flags & RD_MASK) ? "RD":"  ",
            (h->flags & RA_MASK) ? "RA":"  ",  
            ((h->flags & Z_MASK) >> Z_SHIFT),
            rcodetostr(RCODE(h->flags)),
            h->qdcount, h->ancount, h->nscount, h->arcount);

        return buf;
}

static void
dump_packet(const void *data, size_t len)
{
        char            buf[1024];
        struct packed   p;
        struct header   h;
        struct query    q;
        struct rr       rr;
        int             i, an, ns, ar, n;

        packed_init(&p, (char *)data, len);

        if (unpack_header(&p, &h) == -1) {
                printf(";; BAD PACKET: %s\n", p.err);
                return;
        }

        printf(";; HEADER %s\n", print_header(&h, buf, sizeof buf));

        if (h.qdcount)
                printf(";; QUERY SECTION:\n");
        for (i = 0; i < h.qdcount; i++) {
                if (unpack_query(&p, &q) == -1)
                        goto error;
                printf("%s\n", print_query(&q, buf, sizeof buf));
        }

        an = 0;
        ns = an + h.ancount;
        ar = ns + h.nscount;
        n = ar + h.arcount;

        for (i = 0; i < n; i++) {
                if (i == an)
                        printf("\n;; ANSWER SECTION:\n");
                if (i == ns)
                        printf("\n;; AUTHORITY SECTION:\n");
                if (i == ar)
                        printf("\n;; ADDITIONAL SECTION:\n");

                if (unpack_rr(&p, &rr) == -1)
                        goto error;
                printf("%s\n", print_rr(&rr, buf, sizeof buf));
        }

        if (p.offset != len)
                printf(";; REMAINING GARBAGE %zu\n", len - p.offset);

    error:
        if (p.err)
                printf(";; ERROR AT OFFSET %zu/%zu: %s\n", p.offset, p.len,
                    p.err);
}

static const char *
inet6_ntoa(struct in6_addr a)
{
        static char buf[256];
        struct sockaddr_in6     si;

        si.sin6_len = sizeof(si);
        si.sin6_family = PF_INET6;
        si.sin6_addr = a;

        return print_host((struct sockaddr*)&si, buf, sizeof buf);
}

static char*
print_rr(struct rr *rr, char *buf, size_t max)
{
        char    *res;
        char     tmp[256];
        char     tmp2[256];
        int      r;

        res = buf;

        r = snprintf(buf, max, "%s %u %s %s ",
            print_dname(rr->rr_dname, tmp, sizeof tmp),
            rr->rr_ttl,
            classtostr(rr->rr_class),
            typetostr(rr->rr_type));
        if (r == -1) {
                buf[0] = '\0';
                return buf;
        }

        if ((size_t)r >= max)
                return buf;

        max -= r;
        buf += r;

        switch(rr->rr_type) {
        case T_CNAME:
                print_dname(rr->rr.cname.cname, buf, max);
                break;
        case T_MX:
                snprintf(buf, max, "%"PRIu32" %s",
                    rr->rr.mx.preference,
                    print_dname(rr->rr.mx.exchange, tmp, sizeof tmp));
                break;
        case T_NS:
                print_dname(rr->rr.ns.nsname, buf, max);
                break;
        case T_PTR:
                print_dname(rr->rr.ptr.ptrname, buf, max);
                break;
        case T_SOA:
                snprintf(buf, max,
                    "%s %s %" PRIu32 " %" PRIu32 " %" PRIu32 " %" PRIu32 " %" PRIu32,
                    print_dname(rr->rr.soa.rname, tmp, sizeof tmp),
                    print_dname(rr->rr.soa.mname, tmp2, sizeof tmp2),
                    rr->rr.soa.serial,
                    rr->rr.soa.refresh,
                    rr->rr.soa.retry,
                    rr->rr.soa.expire,
                    rr->rr.soa.minimum);
                break;
        case T_A:
                if (rr->rr_class != C_IN)
                        goto other;
                snprintf(buf, max, "%s", inet_ntoa(rr->rr.in_a.addr));
                break;
        case T_AAAA:
                if (rr->rr_class != C_IN)
                        goto other;
                snprintf(buf, max, "%s", inet6_ntoa(rr->rr.in_aaaa.addr6));
                break;
        default:
        other:
                snprintf(buf, max, "(rdlen=%"PRIu16 ")", rr->rr.other.rdlen);
                break;
        }

        return (res);
}

static char*
print_query(struct query *q, char *buf, size_t max)
{
        char b[256];

        snprintf(buf, max, "%s  %s %s",
            print_dname(q->q_dname, b, sizeof b),
            classtostr(q->q_class), typetostr(q->q_type));

        return (buf);
}


static char *
print_host(const struct sockaddr *sa, char *buf, size_t len)
{
        switch (sa->sa_family) {
        case AF_INET:
                inet_ntop(AF_INET, &((struct sockaddr_in*)sa)->sin_addr, buf, len);
                break;
        case AF_INET6:
                inet_ntop(AF_INET6, &((struct sockaddr_in6*)sa)->sin6_addr, buf, len);
                break;
        default:
                buf[0] = '\0';
        }
        return (buf);
}

static char*
print_dname(const char *_dname, char *buf, size_t max)
{
        const unsigned char *dname = _dname;
        char    *res;
        size_t   left, count;

        if (_dname[0] == 0) {
                strlcpy(buf, ".", max);
                return buf;
        }

        res = buf;
        left = max - 1;
        while (dname[0] && left) {
                count = (dname[0] < (left - 1)) ? dname[0] : (left - 1);
                memmove(buf, dname + 1, count);
                dname += dname[0] + 1;
                left -= count;
                buf += count;
                if (left) {
                        left -= 1;
                        *buf++ = '.';
                }
        }
        buf[0] = 0;

        return (res);
}