Tools for Web Applications

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Tools for Web Applications
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Overview of TCP/IP

• Link Layer
• Network Layer
• Transport Layer
• Application Layer

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Protocol Stack Diagram

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Application Layer

• FTP, HTTP, telnet, etc.
• Provides ways for users to interact with the
  network

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Transport Layer

• Transmission Control Protocol(TCP) communicates
  using sockets (IP address and port), provides
  reliable connection
• User Data Protocol(UDP) allows applications to
  send raw IP datagrams

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Network Layer

• Uses Internet Protocol (IP)
• Uses IP addresses
• IP header contains source address, destination
  address, version, length, checksum, etc.

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Link Layer

• Physical interface
• Device driver
• Communicates with the actual network hardware

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Hypertext Transfer Protocol(HTTP)

• Allows clients to request files/other resources
  from a server
• ASCII Protocol easy to talk to

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HTTP Request Methods

• GET - Request to read a web page or whatever
  information is identified by the request-URI
• POST - Append to a named resource (e.g. a Web
  page), or provide a block of data to a
  data-handling process at the server
• HEAD - Request to read a web page's header
• PUT - Request to store a web page
• DELETE - Remove a web page
• LINK - Connects two existing resources
• UNLINK - Breaks an existing connection between
  two resources

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Example

• Type
• telnet www.stanford.edu 80
• GET /class/ee281/index.html HTTP/1.0

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Output

• HTTP/1.1 200 OK
• Date Sat, 23 Nov 2002 063544 GMT
• Server Apache/1.3.26 WebAuth 2.5 (Unix)
  mod_ssl/2.8.10 OpenSSL/0.9.6e WebAuth/2.5
  mod_fastcgi/2.2.12
• Connection close
• Content-Type text/html
• lt!doctype html public "-//w3c//dtd html 4.0
  transitional//en"gt
• lthtmlgt
• ltheadgt
• ltmeta http-equiv"content-type"
  content"text/htmlcharsetiso-8859-1"gt
• ltmeta name"generator" content"Microsoft
  FrontPage 4.0"gt
• lttitlegtEE281 Embedded System Design
  Laboratorylt/titlegt
• ltmeta name"keywords" content"here"gt
• lt/headgt

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Status Codes

• 200 OK
• 201 Created
• 202 Accepted
• 204 No Content
• 301 Moved Permanently
• 302 Moved Temporarily
• 304 Not Modified
• 400 Bad Request
• 401 Unauthorized
• 403 Forbidden
• 404 Not Found
• 500 Internal Server Error
• 501 Not Implemented
• 502 Bad Gateway
• 503 Service Unavailable

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EDTP Ethernet Development Board
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Function Prototypes

• void show_regs(void)
• void show_packet(void)
• void tcp(void)
• void assemble_ack(void)
• void write_asix(unsigned char regaddr, unsigned
  char regdata)
• void read_asix(unsigned char regaddr)
• void get_packet(void)
• void setipaddrs(void)
• void cksum(void)
• void echo_packet(void)
• void send_tcp_packet(void)
• void arp(void)
• void icmp(void)
• void udp(void)

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uIP Free TCP/IP Stack for AVR
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Websites

• uIP
• http//www.dunkels.com/adam/uip
• EDTP Ethernet Board
• http//www.edtp.com
• HTTP
• http//www.graphcomp.com/info/specs/http10.html
• TCP/IP
• http//www4.ulpgc.es/tutoriales/tcpip/pru/3376fm.h
  tm
• http//www.acm.org/crossroads/xrds1-1/tcpjmy.html