From 192e64b65c0e84a9ca86e210884433cb15ab3779 Mon Sep 17 00:00:00 2001
From: hyung-hwan <hyunghwan.chung@gmail.com>
Date: Wed, 12 Feb 2020 15:23:36 +0000
Subject: [PATCH] more code to handle rrdata

---
 mio/lib/dns.c     | 82 +++++++++++++++++++++++++++++++++++------------
 mio/lib/mio-dns.h | 23 ++++++++-----
 2 files changed, 77 insertions(+), 28 deletions(-)

diff --git a/mio/lib/dns.c b/mio/lib/dns.c
index 127bdeb..5782912 100644
--- a/mio/lib/dns.c
+++ b/mio/lib/dns.c
@@ -720,16 +720,75 @@ oops:
 static mio_uint8_t* parse_answer (mio_t* mio, mio_uint8_t* ptr, mio_uint8_t* pktstart, mio_uint8_t* pktend)
 {
 	mio_dns_rrtr_t* rrtr;
+	mio_uint16_t qtype, dlen;
+	mio_oow_t remsize;
 
 //printf ("pktstart = %p pktend = %p, ptr = %p\n", pktstart, pktend, ptr);
 	ptr = parse_domain_name(mio, ptr, pktstart, pktend);
 	if (!ptr) return MIO_NULL;
 
 	rrtr = (mio_dns_rrtr_t*)ptr;
-	ptr += MIO_SIZEOF(*rrtr) + mio_ntoh16(rrtr->dlen);
-	if (MIO_UNLIKELY(ptr >= pktend)) goto oops;
-//printf ("rrtr->dlen => %d\n", mio_ntoh16(rrtr->dlen));
+	if (MIO_UNLIKELY(pktend - ptr < MIO_SIZEOF(*rrtr))) goto oops;
+	ptr += MIO_SIZEOF(*rrtr);
+	dlen = mio_ntoh16(rrtr->dlen);
 
+	if (MIO_UNLIKELY(pktend - ptr < dlen)) goto oops;
+//printf ("rrtr->dlen => %d\n", dlen);
+
+	qtype = mio_ntoh16(rrtr->qtype);
+	remsize = pktend - ptr;
+
+	switch (qtype)
+	{
+		case MIO_DNS_QTYPE_OPT:
+		{
+			/* RFC 6891
+			The extended RCODE and flags, which OPT stores in the RR Time to Live
+			(TTL) field, are structured as follows:
+
+						  +0 (MSB)                            +1 (LSB)
+			   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+			0: |         EXTENDED-RCODE        |            VERSION            |
+			   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+			2: | DO|                           Z                               |
+			   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+			   * 
+			EXTENDED-RCODE
+			 Forms the upper 8 bits of extended 12-bit RCODE (together with the
+			 4 bits defined in [RFC1035].  Note that EXTENDED-RCODE value 0
+			 indicates that an unextended RCODE is in use (values 0 through
+			 15).
+			*/
+
+printf ("OPT RR included....>>>>>>>>>>>>>>>>>>>>>>>>%d\n", (rrtr->ttl >> 24));
+			/*rcode |= (rrtr->ttl >> 24);*/
+			if (((rrtr->ttl >> 16) & 0xFF) != 0) goto oops; /* version not 0 */
+			/* dnsok -> ((rrtr->ttl & 0x8000) >> 15) */
+			/*if ((rrtr->ttl & 0x7FFF) != 0) goto oops;*/ /* Z not 0 - ignore this for now */
+			break;
+		}
+
+		case MIO_DNS_QTYPE_A:
+			if (MIO_UNLIKELY(remsize < 4)) goto oops;
+			break;
+
+		case MIO_DNS_QTYPE_AAAA:
+			if (MIO_UNLIKELY(remsize < 16)) goto oops;
+			break;
+			
+		case MIO_DNS_QTYPE_CNAME:
+		{
+			mio_uint8_t* xptr;
+printf ("\t");
+			xptr = parse_domain_name(mio, ptr, pktstart, pktend);
+			if (!xptr) return MIO_NULL;
+
+			MIO_ASSERT (mio, xptr == ptr + dlen);
+			break;
+		}
+	}
+
+	ptr += dlen;
 	return ptr;
 
 oops:
@@ -792,22 +851,5 @@ printf ("additional %d\n", rrc);
 		if (!ptr) return -1;
 	}
 
-printf ("packet ok...\n");
-#if 0
-	for (i = 0; i < bdns->arcount; i++)
-	{
-	#if 0
-		if (*ptr == 0)
-		{
-			rrtr = (mio_ptrs_rrtr_t*)(ptr + 1);
-			if (rrtr->qtype == MIO_CONST_HTON16(MIO_DNS_QTYPE_OPT)
-			{
-				/* edns */
-			}
-		}
-	#endif
-	}
-#endif
-
 	return 0;
 }
diff --git a/mio/lib/mio-dns.h b/mio/lib/mio-dns.h
index aaf21d0..7d3f03f 100644
--- a/mio/lib/mio-dns.h
+++ b/mio/lib/mio-dns.h
@@ -265,29 +265,29 @@ typedef struct mio_dns_brr_t mio_dns_brr_t;
 
 #if 0
 /* A RDATA */
-struct mio_dns_brd_a_t 
+struct mio_dns_brrd_a_t 
 {
 };
-typedef struct mio_dns_brd_a_t mio_dns_brd_a_t;
+typedef struct mio_dns_brrd_a_t mio_dns_brrd_a_t;
 
 /* 3.3.1 CNAME RDATA format */
-struct mio_dns_brd_cname_t
+struct mio_dns_brrd_cname_t
 {
 };
-typedef struct mio_dns_brd_cname_t mio_dns_brc_cname_t;
+typedef struct mio_dns_brrd_cname_t mio_dns_brc_cname_t;
 
 
 /* 3.3.9 MX RDATA format */
-struct mio_dns_brd_mx_t
+struct mio_dns_brrd_mx_t
 {
 	mio_uint16_t preference;
 	mio_bch_t*   exchange;
 };
-typedef struct mio_dns_brd_mx_t mio_dns_brd_mx_t;
+typedef struct mio_dns_brrd_mx_t mio_dns_brrd_mx_t;
 
 
 
-struct mio_dns_brd_soa_t
+struct mio_dns_brrd_soa_t
 {
 	mio_bch_t*   mname;
 	mio_bch_t*   rname; 
@@ -297,7 +297,7 @@ struct mio_dns_brd_soa_t
 	mio_uint32_t expire;
 	mio_uint32_t minimum;
 };
-typedef struct mio_dns_brd_soa_t mio_dns_brd_soa_t;
+typedef struct mio_dns_brrd_soa_t mio_dns_brrd_soa_t;
 #endif
 
 struct mio_dns_beopt_t
@@ -376,6 +376,13 @@ MIO_EXPORT int mio_svc_dnc_resolve (
 	mio_svc_dnc_on_reply_t on_reply
 );
 
+
+MIO_EXPORT int mio_dns_parse_packet (
+	mio_svc_dnc_t*  dnc,
+	mio_dns_pkt_t*  pkt,
+	mio_oow_t       len,
+	mio_dns_bdns_t* bdns
+);
 #if defined(__cplusplus)
 }
 #endif