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trying to implement dns cookie handling

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hyung-hwan 2020-06-30 16:11:39 +00:00
parent 8f8c32c525
commit 3c77ca433b
1 changed files with 24 additions and 1 deletions
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25
mio/lib/dns.c
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@ -256,6 +256,9 @@ static int parse_answer_rr (mio_t* mio, mio_dns_rr_part_t rr_part, mio_oow_t pos
{ {
case MIO_DNS_RRT_OPT: case MIO_DNS_RRT_OPT:
{ {
mio_uint16_t eopt_tot_len, eopt_len;
mio_dns_eopt_t* eopt;
/* RFC 6891 /* RFC 6891
The extended RCODE and flags, which OPT stores in the RR Time to Live The extended RCODE and flags, which OPT stores in the RR Time to Live
(TTL) field, are structured as follows: (TTL) field, are structured as follows:
@ -280,7 +283,27 @@ static int parse_answer_rr (mio_t* mio, mio_dns_rr_part_t rr_part, mio_oow_t pos
pi->edns.version = (rrtr->ttl >> 16) & 0xFF; pi->edns.version = (rrtr->ttl >> 16) & 0xFF;
pi->edns.dnssecok = ((rrtr->ttl & 0x8000) >> 15); pi->edns.dnssecok = ((rrtr->ttl & 0x8000) >> 15);
/*if ((rrtr->ttl & 0x7FFF) != 0) goto oops;*/ /* Z not 0 - ignore this for now */ /*if ((rrtr->ttl & 0x7FFF) != 0) goto oops;*/ /* Z not 0 - ignore this for now */
goto verbatim;
eopt = (mio_dns_eopt_t*)(rrtr + 1);
eopt_tot_len = dlen;
while (eopt_tot_len > 0)
{
if (eopt_tot_len < MIO_SIZEOF(mio_dns_eopt_t)) goto oops;
eopt_len = mio_ntoh16(eopt->dlen);
if (eopt_tot_len - MIO_SIZEOF(mio_dns_eopt_t) < eopt_len) goto oops; /* wrong eopt length */
if (eopt->code == MIO_CONST_HTON16(MIO_DNS_EOPT_COOKIE))
{
if (eopt_len < 8) goto oops; /* the client cookie must be 8 bytes */
/* TODO: dns cookies */
}
eopt_tot_len -= MIO_SIZEOF(mio_dns_eopt_t) + eopt_len;
eopt = (mio_dns_eopt_t*)((mio_uint8_t*)eopt + MIO_SIZEOF(mio_dns_eopt_t) + eopt_len);
}
goto verbatim; /* keep the entire option data including cookies */
} }
case MIO_DNS_RRT_A: case MIO_DNS_RRT_A: