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work in progress - implementing the dns cookie support in mio_svc_dnc_resolve()

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hyung-hwan
2020-07-01 15:54:23 +00:00
parent 970deb9966
commit fe478e954d
4 changed files with 48 additions and 5 deletions
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44
mio/lib/dns-cli.c
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@ -862,7 +862,7 @@ static void on_dnc_resolve (mio_svc_dnc_t* dnc, mio_dns_msg_t* reqmsg, mio_errnu
if (!(reqmsgxtn->flags & MIO_SVC_DNC_RESOLVE_FLAG_BRIEF))
{
/* the full reply packet is requested. no transformation is required */
if (reqmsgxtn->on_resolve) reqmsgxtn->on_resolve(dnc, reqmsg, status, data, dlen);
if (reqmsgxtn->on_resolve) reqmsgxtn->on_resolve (dnc, reqmsg, status, data, dlen);
return;
}
@ -965,7 +965,7 @@ mio_dns_msg_t* mio_svc_dnc_resolve (mio_svc_dnc_t* dnc, const mio_bch_t* qname,
MIO_DNS_RCODE_NOERROR /* rcode */
};
static mio_dns_bedns_t qedns =
mio_dns_bedns_t qedns =
{
4096, /* uplen */
@ -976,6 +976,8 @@ mio_dns_msg_t* mio_svc_dnc_resolve (mio_svc_dnc_t* dnc, const mio_bch_t* qname,
MIO_NULL
};
mio_dns_beopt_t beopt_cookie;
mio_dns_bqr_t qr;
mio_dns_msg_t* reqmsg;
dnc_dns_msg_resolve_xtn_t* resolxtn;
@ -984,11 +986,49 @@ mio_dns_msg_t* mio_svc_dnc_resolve (mio_svc_dnc_t* dnc, const mio_bch_t* qname,
qr.qtype = qtype;
qr.qclass = MIO_DNS_RRC_IN;
if (resolve_flags & MIO_SVC_DNC_RESOLVE_FLAG_COOKIE)
{
static mio_uint8_t dummy[48];
beopt_cookie.code = MIO_DNS_EOPT_COOKIE;
beopt_cookie.dlen = MIO_COUNTOF(dummy);
beopt_cookie.dptr = dummy;
qedns.beonum = 1;
qedns.beoptr = &beopt_cookie;
}
reqmsg = make_dns_msg(dnc, &qhdr, &qr, 1, MIO_NULL, 0, &qedns, on_dnc_resolve, MIO_SIZEOF(*resolxtn) + xtnsize);
if (reqmsg)
{
int send_flags;
if (resolve_flags & MIO_SVC_DNC_RESOLVE_FLAG_COOKIE)
{
/* ASSUMPTIONS:
* the eopt entries are at the back of the packet.
* only 1 eopt entry(MIO_DNS_EOPT_COOKIE) has been added.
*
* manipulate the data length of the EDNS0 RR and COOKIE option
* as if the server cookie data has not been added.
*/
mio_dns_rrtr_t* edns_rrtr;
mio_dns_eopt_t* eopt;
/* TODO: generate the client cookie and copy it */
/* if the server cookie is available, copy it to the packet. but the server cookike may still be shorter than 40. so some manipulation is still needed
* if not, manipualte the length like below */
edns_rrtr = (mio_dns_rrtr_t*)((mio_uint8_t*)mio_dns_msg_to_pkt(reqmsg) + reqmsg->ednsrrtroff);
reqmsg->pktlen -= 40; /* maximum server cookie space */
MIO_ASSERT (dnc->mio, edns_rrtr->rrtype == MIO_CONST_HTON16(MIO_DNS_RRT_OPT));
MIO_ASSERT (dnc->mio, edns_rrtr->dlen == MIO_CONST_HTON16(52));
edns_rrtr->dlen = MIO_CONST_HTON16(12);
eopt = (mio_dns_eopt_t*)(edns_rrtr + 1);
MIO_ASSERT (dnc->mio, eopt->dlen == MIO_CONST_HTON16(48));
eopt->dlen = MIO_CONST_HTON16(8);
}
resolxtn = dnc_dns_msg_resolve_getxtn(reqmsg);
resolxtn->on_resolve = on_resolve;
resolxtn->qtype = qtype;

3
mio/lib/dns.c
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@ -746,7 +746,7 @@ mio_dns_msg_t* mio_dns_make_msg (mio_t* mio, mio_dns_bhdr_t* bhdr, mio_dns_bqr_t
/* TODO: msg buffer reuse */
msg = mio_callocmem(mio, msgbufsz);
if (!msg) return MIO_NULL;
if (MIO_UNLIKELY(!msg)) return MIO_NULL;
msg->msglen = msgbufsz; /* record the instance size */
msg->pktalilen = MIO_ALIGN_POW2(pktlen, MIO_SIZEOF_VOID_P);
@ -812,6 +812,7 @@ mio_dns_msg_t* mio_dns_make_msg (mio_t* mio, mio_dns_bhdr_t* bhdr, mio_dns_bqr_t
beopt = edns->beoptr;
eopt = (mio_dns_eopt_t*)dn;
msg->ednsrrtroff = (mio_uint8_t*)rrtr - (mio_uint8_t*)pkt;
for (i = 0; i < edns->beonum; i++)
{

4
mio/lib/mio-dns.h
View File

@ -162,6 +162,7 @@ typedef struct mio_dns_msg_t mio_dns_msg_t;
struct mio_dns_msg_t
{
mio_oow_t msglen;
mio_oow_t ednsrrtroff; /* offset to trailing data after the name in the dns0 RR*/
mio_oow_t pktlen;
mio_oow_t pktalilen;
};
@ -405,8 +406,9 @@ enum mio_svc_dnc_resolve_flag_t
/* the following flag bits are resolver specific. it must not overlap with send flag bits */
MIO_SVC_DNC_RESOLVE_FLAG_BRIEF = (1 << 8),
MIO_SVC_DNC_RESOLVE_FLAG_COOKIE = (1 << 9),
MIO_SVC_DNC_RESOLVE_FLAG_ALL = (MIO_SVC_DNC_RESOLVE_FLAG_PREFER_TCP | MIO_SVC_DNC_RESOLVE_FLAG_TCP_IF_TC | MIO_SVC_DNC_RESOLVE_FLAG_BRIEF)
MIO_SVC_DNC_RESOLVE_FLAG_ALL = (MIO_SVC_DNC_RESOLVE_FLAG_PREFER_TCP | MIO_SVC_DNC_RESOLVE_FLAG_TCP_IF_TC | MIO_SVC_DNC_RESOLVE_FLAG_BRIEF | MIO_SVC_DNC_RESOLVE_FLAG_COOKIE)
};
typedef enum mio_svc_dnc_resolve_flag_t mio_svc_dnc_resolve_flag_t;