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/* ISC license. */
#include <stdint.h>
#include <skalibs/uint16.h>
#include <skalibs/strerr2.h>
#include <skalibs/gensetdyn.h>
#include <s6-dns/s6dns-constants.h>
#include <s6-dns/s6dns-domain.h>
#include <s6-dns/s6dns-message.h>
#include <s6-dns/s6dns-engine.h>
#include "dnsfunneld.h"
static gensetdyn rinfo = GENSETDYN_INIT(uint8_t, 16, 3, 8) ;
#define RINFO(i) GENSETDYN_P(uint8_t, &rinfo, i)
int query_process_init ()
{
return 1 ;
}
void query_process_reload ()
{
}
void query_process_question (uint32_t ops, s6dns_domain_t const *d, uint16_t qtype, uint16_t id, uint32_t ip, uint16_t port)
{
if (ops & 2 && (qtype == S6DNS_T_A || qtype == S6DNS_T_AAAA))
{
uint32_t i ;
if (!gensetdyn_new(&rinfo, &i)) strerr_diefu1sys(111, "process query") ;
*RINFO(i) = (qtype == S6DNS_T_AAAA) << 7 ;
query_new(d, S6DNS_T_A, id, ip, port, i+1) ;
query_new(d, S6DNS_T_AAAA, id, ip, port, i+1) ;
}
else query_new(d, qtype, id, ip, port, 0) ;
}
static inline unsigned int truncate_packet (char *s, unsigned int olen)
{
s6dns_message_header_t hdr ;
s6dns_message_counts_t counts ;
unsigned int section ;
unsigned int pos ;
if (!s6dns_message_parse_init(&hdr, &counts, s, olen, &pos)) return 0 ;
if (hdr.rcode) return 0 ;
section = s6dns_message_parse_skipqd(&counts, s, olen, &pos) ;
while (section)
{
s6dns_message_rr_t rr ;
s6dns_message_counts_t newcounts = counts ;
unsigned int tmp = pos ;
if (!s6dns_message_parse_getrr(&rr, s, olen, &tmp)) return 0 ;
section = s6dns_message_parse_next(&newcounts, &rr, s, olen, &tmp) ;
if (tmp > 512)
{
hdr.counts.qd -= counts.qd ;
hdr.counts.an -= counts.an ;
hdr.counts.ns -= counts.ns ;
hdr.counts.nr -= counts.nr ;
s6dns_message_header_pack(s, &hdr) ;
return pos ;
}
pos = tmp ;
counts = newcounts ;
}
return olen ;
}
static inline uint16_t extract_qtype (dfquery_t const *q)
{
s6dns_domain_t name ;
uint16_t qtype ;
uint16_t len ;
s6dns_message_header_t hdr ;
s6dns_message_counts_t counts ;
unsigned int pos ;
uint16_unpack_big(q->dt.sa.s, &len) ;
if (!s6dns_message_parse_init(&hdr, &counts, q->dt.sa.s + 2, len, &pos)) return 0 ;
if (!s6dns_message_parse_question(&counts, &name, &qtype, q->dt.sa.s + 2, len, &pos)) return 0 ;
return qtype ;
}
static int isnxdomain (dfquery_t const *q)
{
s6dns_message_header_t hdr ;
s6dns_message_counts_t counts ;
unsigned int pos ;
if (!s6dns_message_parse_init(&hdr, &counts, s6dns_engine_packet(&q->dt), s6dns_engine_packetlen(&q->dt), &pos)) return 0 ;
return hdr.rcode == 3 ;
}
static int input_event (dfquery_t const *q, unsigned int ev)
{
static uint8_t const table[5][6] =
{
{ 0x11, 0x03, 0x81, 0x02, 0x02, 0x04 },
{ 0x06, 0x06, 0x06, 0x05, 0x05, 0x05 },
{ 0x15, 0x25, 0x85, 0x06, 0x06, 0x06 },
{ 0x06, 0x06, 0x06, 0x25, 0x25, 0x45 },
{ 0x15, 0x45, 0x85, 0x06, 0x06, 0x06 }
} ;
uint8_t b = *RINFO(q->procid - 1) ;
uint8_t isaux = 3 * (b >> 7 != (extract_qtype(q) == S6DNS_T_AAAA)) ;
uint8_t state = (b >> isaux) & 7 ;
uint8_t c = table[state][ev + isaux] ;
state = c & 7 ;
*RINFO(q->procid - 1) = (b & ~(7 << isaux)) | (state << isaux) ;
if (c & 0x10) dfanswer_fail(q) ;
if (c & 0x20) dfanswer_nxdomain(q) ;
if (c & 0x40) dfanswer_nodata(q) ;
if (c & 0x80) dfanswer_pass(q, s6dns_engine_packet(&q->dt), s6dns_engine_packetlen(&q->dt)) ;
if (state >= 6) strerr_dief1x(101, "problem in main/aux transition table; please submit a bug-report.") ;
if (state == 5) gensetdyn_delete(&rinfo, q->procid - 1) ;
return !!(c & 0xf0) ;
}
void query_process_response_failure (uint32_t ops, dfquery_t const *q)
{
if (ops & 2 && q->procid && input_event(q, 0)) return ;
else dfanswer_fail(q) ;
}
void query_process_response_success (uint32_t ops, dfquery_t const *q)
{
if (ops & 2 && q->procid && input_event(q, 1 + !isnxdomain(q))) return ;
if (ops & 1 && s6dns_engine_packetlen(&q->dt) > 512)
{
unsigned int len = truncate_packet(s6dns_engine_packet(&q->dt), s6dns_engine_packetlen(&q->dt)) ;
if (!len) dfanswer_fail(q) ;
else dfanswer_pass(q, s6dns_engine_packet(&q->dt), len) ;
}
else dfanswer_pass(q, s6dns_engine_packet(&q->dt), s6dns_engine_packetlen(&q->dt)) ;
}
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