EVB-B1+ WIZnet, EVB-B1+ Datasheet - Page 91

• Manufacturer Part Number: EVB-B1+
• Description: Development Boards & Kits - ARM W3150A+EVAL BOARD BASED ON AVR
• Manufacturer: WIZnet

Specifications of EVB-B1+

• Rohs: yes
• Product: Evaluation Boards
• Interface Type: RS-232, SPI
• Operating Supply Voltage: 3.3 V, 5 V
• Data Bus Width: 8 bit
• Dimensions: 50 mm x 40 mm
• Processor Series: ATmega128

<Fig 3.38: gethostbyaddr() & gethostbyname()>
dns_query() initializes the buffer that is needed for DNS inter-working and creates QNAME of Question
Section based on Query Type ‘BYNAME’, and ‘BYIP.’ If the Query Type is ‘BYNAME,’ that is, when querying
the Domain Name with IP Address, Domain Name can be used as QNAME without transformation.
When Query Type is ‘BYIP,’ that is, when querying the Domain Name with IP Address, change IP Address to
IP Address String and QNAME is used after adding “in-addr.arpa” to the changed IP Address String. After
the creation of QNAME, UDP Socket is created for DNS inter-working and DNS Request Message is created
by calling dns_make_query(). If DNS Request Message is created successfully DNS Request Message is
sent to DNS Name Server through UDP Socket. After sending DNS Request Message it receives DNS
Response Message or waits until the waiting time is expired.
If DNS response message is received from DNS name server during the waiting time, it analyzes received
DNS response message using dns_parse_response().dns_query() returns IP Address or Domain Name
depending on Query Type.
<Fig 3.39> is dns_query()’s process map
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