Tools for Web Applications

Overview of TCP/IP Link Layer Network Layer Transport Layer Application Layer

Protocol Stack Diagram

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

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

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

Link Layer Physical interface Device driver Communicates with the actual network hardware

Hypertext Transfer Protocol(HTTP) Allows clients to request files/other resources from a server ASCII Protocol – easy to talk to

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

Example Type: telnet 80 GET /class/ee281/index.html HTTP/1.0

Output HTTP/ OK Date: Sat, 23 Nov :35:44 GMT Server: Apache/ WebAuth 2.5 (Unix) mod_ssl/ OpenSSL/0.9.6e WebAuth/2.5 mod_fastcgi/ Connection: close Content-Type: text/html EE281: Embedded System Design Laboratory ……………………

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

EDTP Ethernet Development Board

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);

uIP – Free TCP/IP Stack for AVR

Websites uIP: EDTP Ethernet Board: HTTP: TCP/IP: