EVB-PIC24 WIZnet, EVB-PIC24 Datasheet - Page 95

• Manufacturer Part Number: EVB-PIC24
• Description: Development Boards & Kits - PIC / DSPIC W3150A+EVAL BOARD BASED ON PIC24
• Manufacturer: WIZnet

Specifications of EVB-PIC24

• Rohs: yes
• Product: Development Kits
• Interface Type: RS-232
• Data Bus Width: 16 bit
• Dimensions: 50 mm x 40 mm

dns_parse_question() analyses and processes Question Section. There are no information that actually used
in the Question Section of DNS Request Message but it must be processed to get the starting position of
Answer Section. Since QNAME Field of Question Section gets variable length, parse_name() processes
Extract & convert the QNAME field In Question Section
cp += len
cp += 20
RETURN
u_ int len ;
RETURN
cp
char name[ MAX_ QNAME _ LEN];
Declare & Initialize Local Variables
Extract &
cp
RETURN
NULL
len = parse _ name ( name )
dns_ parse _ question ()
len = parse _name( qname)
N
cp += len
cp += 4
RETURN cp
strcpy (get_ domain _ name , qname )
Copy qname to get _ domain _ name
N
Y
len == 0
convert the RDDATA field In Answer Section
len = parse _ name ( qname )
query _ data == BYNAME
Y
N
query _ data == BYIP
get _ domain _ ip = tip
type==TYPE_ PTR
len == 0
© Copyright 2006 WIZnet Co., Inc. All rights reserved.
<Fig 3.43: dns_parse_question() & dns_answer()>
cp += len
len == 0
Y
&&
Y
N
N
Y
RETURN
NULL
cp += len
cp += len
*((( u_ c har *)&tip) + 1 ) = *cp++;
*(((u_ char*)&tip ) + 2 ) = *cp++;
*(((u_ char*)&tip ) + 3 ) = *cp++;
*((u_ char*)&tip) = *cp++
Extract the IP Address in cp
RETURN
len = parse _ name( qname )
cp
and then assign it to tip
N
Len = parse _ name ( qname )
N
len == 0
len = *cp++
cp += len
len = *cp++
cp += len
len == 0
Y
Extract &
RETURN
NULL
char qname[ MAX_ QNAME _ LEN];
u_ long tip ;
Y
int len, type;
Declare & Initialize Local Variables
Skip CLASS , TTL , RDLENGTH
Y
Y
Y
Y
Y
Y
Y
Y
len = parse _ name( qname )
convert the NAME field In Answer Section
cp += 2
cp += 2
RETURN
type = *((u_int*)cp)
NULL
type == TYPE_A
TYPE_ CNAME
TYPE_ HINFO
dns_ answer ( )
TYPE_ PTR
TYPE_ MG
TYPE_MB
TYPE_ MR
TYPE_ NS
len == 0
cp += 8
N
N
N
Y
Y
Y
TYPE_ SOA
TYPE_ TXT
TYPE_ MX
N
RETURN
cp
N
N
N
RETURN
NULL
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