ipv4的icmp包长度74bytes，也就是592bits，其中包头20bytes，数据长度是32bytes
IP报文不就是以太网报文吗？
下边是用wireshark抓的包
No.TimeSourceDestinationProtocolLengthInfo
415511.454821172.21.236.81172.30.51.133ICMP74Echo(ping)requestid=0x0400,seq=30525/15735,ttl=123
Frame415:74bytesonwire(592bits),74bytescaptured(592bits)
ArrivalTime:Feb24,201116:43:53.510964000中国标准时间
EpochTime:1298537033.510964000seconds
[Timedeltafrompreviouscapturedframe:1.000035000seconds]
[Timedeltafrompreviousdisplayedframe:1.000035000seconds]
[Timesincereferenceorfirstframe:511.454821000seconds]
FrameNumber:415
FrameLength:74bytes(592bits)
CaptureLength:74bytes(592bits)
[Frameismarked:False]
[Frameisignored:False]
[Protocolsinframe:eth:ip:icmp:data]
[ColoringRuleName:ICMP]
[ColoringRuleString:icmp||icmpv6]
EthernetII,Src:Hangzhou_a1:9c:65(00:23:89:a1:9c:65),Dst:QuantaCo_39:b7:74(60:eb:69:39:b7:74)
Destination:QuantaCo_39:b7:74(60:eb:69:39:b7:74)
Address:QuantaCo_39:b7:74(60:eb:69:39:b7:74)
.......0................=IGbit:Individualaddress(unicast)
......0.................=LGbit:Globallyuniqueaddress(factorydefault)
Source:Hangzhou_a1:9c:65(00:23:89:a1:9c:65)
Address:Hangzhou_a1:9c:65(00:23:89:a1:9c:65)
.......0................=IGbit:Individualaddress(unicast)
......0.................=LGbit:Globallyuniqueaddress(factorydefault)
Type:IP(0x0800)
InternetProtocol,Src:172.21.236.81(172.21.236.81),Dst:172.30.51.133(172.30.51.133)
Version:4
Headerlength:20bytes
DifferentiatedServicesField:0x00(DSCP0x00:Default;ECN:0x00:Not-ECT(NotECN-CapableTransport))
000000..=DifferentiatedServicesCodepoint:Default(0x00)
......00=ExplicitCongestionNotification:Not-ECT(NotECN-CapableTransport)(0x00)
TotalLength:60
Identification:0xac13(44051)
Flags:0x00
0.......=Reservedbit:Notset
.0......=Don'tfragment:Notset
..0.....=Morefragments:Notset
Fragmentoffset:0
Timetolive:123
Protocol:ICMP(1)
Headerchecksum:0x1ba3[correct]
[Good:True]
[Bad:False]
Source:172.21.236.81(172.21.236.81)
Destination:172.30.51.133(172.30.51.133)
InternetControlMessageProtocol
Type:8(Echo(ping)request)
Code:0
Checksum:0xd21e[correct]
Identifier(BE):1024(0x0400)
Identifier(LE):4(0x0004)
Sequencenumber(BE):30525(0x773d)
Sequencenumber(LE):15735(0x3d77)
Data(32bytes)
Data:6162636465666768696a6b6c6d6e6f707172737475767761...
[Length:32]
000060eb6939b774002389a19c6508004500`.i9.t.#...e..E.
0010003cac1300007b011ba3ac15ec51ac1e.<....{......Q..
002033850800d21e0400773d6162636465663.......w=abcdef
00306768696a6b6c6d6e6f70717273747576ghijklmnopqrstuv
004077616263646566676869wabcdefghi
