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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:
{
mio_uint16_t eopt_tot_len, eopt_len;
mio_dns_eopt_t* eopt;
/* RFC 6891
The extended RCODE and flags, which OPT stores in the RR Time to Live
(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.dnssecok = ((rrtr->ttl & 0x8000) >> 15);
/*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: