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/* Copyright (C) 2020 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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 3 of the License, 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, see <https://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libknot/descriptor.h>
#include <libknot/dname.h>
#include "load_queries.h"
#define ERR_PREFIX "failed loading queries "
uint16_t global_edns_size = 1232;
enum qflags {
QFLAG_EDNS = 1,
QFLAG_DO = 2,
};
struct pkt_payload *global_payloads = NULL;
void free_global_payloads()
{
struct pkt_payload *g_payloads_p = global_payloads, *tmp;
while (g_payloads_p != NULL) {
tmp = g_payloads_p;
g_payloads_p = tmp->next;
free(tmp);
}
}
bool load_queries(const char *filename)
{
FILE *f = fopen(filename, "r");
if (f == NULL) {
printf(ERR_PREFIX "file '%s' (%s)\n", filename, strerror(errno));
return false;
}
struct pkt_payload *g_payloads_top = NULL;
struct {
char line[KNOT_DNAME_TXT_MAXLEN + 256];
char dname_txt[KNOT_DNAME_TXT_MAXLEN + 1];
uint8_t dname[KNOT_DNAME_MAXLEN];
char type_txt[128];
char flags_txt[128];
} *bufs;
bufs = malloc(sizeof(*bufs)); // avoiding too much stuff on stack
if (bufs == NULL) {
printf(ERR_PREFIX "(out of memory)\n");
goto fail;
}
while (fgets(bufs->line, sizeof(bufs->line), f) != NULL) {
bufs->flags_txt[0] = '\0';
int ret = sscanf(bufs->line, "%s%s%s", bufs->dname_txt, bufs->type_txt, bufs->flags_txt);
if (ret < 2) {
printf(ERR_PREFIX "(faulty line): '%.*s'\n",
(int)strcspn(bufs->line, "\n"), bufs->line);
goto fail;
}
void *pret = knot_dname_from_str(bufs->dname, bufs->dname_txt, sizeof(bufs->dname));
if (pret == NULL) {
printf(ERR_PREFIX "(faulty dname): '%s'\n", bufs->dname_txt);
goto fail;
}
uint16_t type;
ret = knot_rrtype_from_string(bufs->type_txt, &type);
if (ret < 0) {
printf(ERR_PREFIX "(faulty type): '%s'\n", bufs->type_txt);
}
enum qflags flags = 0;
switch (bufs->flags_txt[0]) {
case '\0':
break;
case 'e':
case 'E':
flags |= QFLAG_EDNS;
break;
case 'd':
case 'D':
flags |= QFLAG_EDNS | QFLAG_DO;
break;
default:
printf(ERR_PREFIX "(faulty flag): '%s'\n", bufs->flags_txt);
goto fail;
}
size_t dname_len = knot_dname_size(bufs->dname);
size_t pkt_len = 16 + dname_len;
if (flags & QFLAG_EDNS) {
pkt_len += 11;
}
struct pkt_payload *pkt = calloc(1, sizeof(void *) + sizeof(size_t) + pkt_len);
if (pkt == NULL) {
printf(ERR_PREFIX "(out of memory)\n");
goto fail;
}
pkt->len = pkt_len;
pkt->payload[2] = 0x01; // QR bit
pkt->payload[5] = 0x01; // 1 question
pkt->payload[11] = (flags & QFLAG_EDNS) ? 0x01 : 0x00;
memcpy(pkt->payload + 12, bufs->dname, dname_len);
pkt->payload[dname_len + 12] = type >> 8;
pkt->payload[dname_len + 13] = type & 0xff;
pkt->payload[dname_len + 15] = 0x01; // class IN
if (flags & QFLAG_EDNS) {
pkt->payload[dname_len + 18] = 41; // OPT RRtype
pkt->payload[dname_len + 19] = global_edns_size >> 8;
pkt->payload[dname_len + 20] = global_edns_size & 0xff;
pkt->payload[dname_len + 23] = (flags & QFLAG_DO) ? 0x80 : 0x00;
}
// add pkt to list global_payloads
if (g_payloads_top == NULL) {
global_payloads = pkt;
g_payloads_top = pkt;
} else {
g_payloads_top->next = pkt;
g_payloads_top = pkt;
}
}
if (global_payloads == NULL) {
printf(ERR_PREFIX "(no queries in file)\n");
goto fail;
}
free(bufs);
fclose(f);
return true;
fail:
free_global_payloads();
free(bufs);
fclose(f);
return false;
}
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