1 / 11

Lab-4 ICMP Ping Programming

Lab-4 ICMP Ping Programming. Speaker : Yi-Fong Lin Date:2007.11.28. IP & ICMP. IP – Internet Protocol ICMP - Internet Control Message Protocol IP & ICMP insert into Ethernet packet. Ethernet 封包. IP 封包. DA MAC. SA MAC. TYPE 0x0800. IP header. ICMP header. ICMP data. ICMP 封包

sorcha
Download Presentation

Lab-4 ICMP Ping Programming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lab-4 ICMP Ping Programming Speaker : Yi-Fong Lin Date:2007.11.28

  2. IP & ICMP • IP – Internet Protocol • ICMP - Internet Control Message Protocol • IP & ICMP insert into Ethernet packet Ethernet 封包 IP 封包 DA MAC SA MAC TYPE 0x0800 IP header ICMP header ICMP data ICMP 封包 (IP data)

  3. IP header 0 8 16 24 31 SERVICE TYPE TOTAL LENGTH VERS HLEN IDENTIFICATION FRAGMENT OFFSET FLAGS 5個4Bytes TIME TO LIVE PROTOCOL HEADER CHECKSUM SOURCE IP DESTINATION IP IP OPTION(IF ANY) PADDING 不使用

  4. IP header • VERS：IP協定的版本號碼,IPv4:0x4 • HLEN：IP表頭長度,4 bytes為單位, no option : 0x05 • SERVICE TYPE： • PRECEDENCE : 優先權 • D : No Delay • H : High Throughput • R : High Reliability • TOTAL LENGTH：IP header跟data的總長度,byte為單位。 • IDENTIFICATION：IP封包的編號。 7 6 5 4 3 0 保留 D T R PRECEDENCE

  5. IP header • FLAGS、FRAGMENTOFFSET • TIME TO LIVE(TTL)：定義一封包在網路系統中存活的時間。 • PROTOCOL：UDP：0x11 TCP：0x06 ICMP：0x01 • HEADER CHECKSUM • SOURCE IP、DESTINATION IP

  6. ICMP types TYPE ICMP Message Type 0 Echo Reply 3 Destination Unreachable 4 Source quench 5 Redirect 8 Echo Request (Ping) 11 Time Exceeded for a Datagram 12 Parameter Problem on a Datagram 13 Timestamp Request 14 Timestamp Reply 15 Information Request 16 Information Reply 17 Address Mask Request 18 Address Mask Reply

  7. CheckSum 0 4 8 16 31 0x00 0x04 0x05 0x00 0x0100 0x0050 0x00 0x80 0x01 checksum Destination IP 0x8C.0x7D.0x21.0x01 0x8C.0x7D.0x21.0x02 Source IP IP OPTION(IF ANY) PADDING

  8. CheckSum 計算法 • 每16bit做相加 • Ex: • 0x4 5 0 0 • 0x0 0 0 0 • 0x0 1 0 0 • 0x0 0 5 0 • 0x8 0 0 1 • 0x0 0 0 0 • 0x8 C7 D • 0x2 1 0 1 • 0x8 C7 D • 0x2 1 0 2 CheckSum DE AF + 2 2 1 4 E + 2 1 5 0 =>取1的補數 =>1101 1110 1010 1111(DEAF)

  9. Ping 140.125.33.10 ARP Who is 140.125.33.12 Ping 140.125.33.12 MAC=03:04:05:06:07:08 ICMP Request 140.125.32.18 I am 140.125.33.12 My MAC is 03:04:05:06:07:08 ICMP Reply 140.125.33.12

  10. ICMP • Format 0 8 16 24 31 TYPE(8or0) CHECKSUM CODE(0) IDENTIFIER SEQUENCE NUMBER OPTION DATA… • checksum：ICMP header跟data的checksum • Identifier、sequence是request sender用來檢查reply封包是回應哪一個request封包。 • option data長度是可變動的，reply回的option 必需跟 request一樣。 • command: ping {目地 IP}

  11. Lab Work • 透過 Uart interface 可用下指令的方式ping 至其他連接到網路的裝置，並且顯示分析 ICMP echo request/reply封包。 • 可回覆 ICMP echo request 封包，即接受網路上其他裝置的 ping 要求。

More Related