pkt
1.0.0
Erlangネットワークプロトコルライブラリ。
もともとEPCAPの一部：http：//github.com/msantos/epcap
pkt:decapsulate(Data) -> Packet
pkt:decapsulate(Proto, Data) -> Packet
Types Data = binary()
Proto = atom() | integer()
Packet = [ Header | Payload ]
Header = #ether{} | #arp{} | #null{} | #linux_cooked{} |
#ipv4{} | #ipv6{} | #tcp{} | #udp{} | #sctp{} | #icmp{} |
#icmp6{} | #igmp{} | #gre{} | #llc{} | #vrrp{} | #'802.1q'{} |
#lldp{} | #mpls{} | #rarp{} | #'802.1x'{}
Payload = binary()
Convert network protocols from binary data to a list of Erlang
records followed by the payload.
decapsulate/1,2 works on valid packets. If the packet is malformed
or unsupported, decapsulate/1 will crash.
decapsulate/1 parses the data as an ethernet frame.
decapsulate/2 allows specifying the protocol for decoding the
packet. If the protocol is specified as an integer, the integer
is treated as a datalink type.
pkt:decode(Data) -> {ok, Packet} | {error, SoFar, {FailedProto, binary()}}
pkt:decode(Proto, Data) -> {ok, Packet} | {error, SoFar, {FailedProto, binary()}}
Types Data = binary()
Proto = FailedProto = atom()
Packet = {Headers, Payload}
Headers = [Header]
Header = #ether{} | #arp{} | #null{} | #linux_cooked{} |
#ipv4{} | #ipv6{} | #tcp{} | #udp{} | #sctp{} | #icmp{} |
#icmp6{} | #igmp{} | #gre{} | #llc{} | #vrrp{} | #'802.1q'{} |
#lldp{} | #mpls{} | #rarp{} | #'802.1x'{}
SoFar = Headers | []
Payload = binary()
Similar to decapsulate/1 but, on error, returns any part of the
packet that has been successfully converted to Erlang term format.
次の関数は、レコードとバイナリの間を変換するプロトコルヘッダーを作成します。レコードタイプの定義については、include/pkt.hrlを参照してください。
ether(Packet) -> {#ether{}, Payload} | binary()
llc(Packet) -> {#llc{}, Payload} | binary()
vrrp(Packet) -> {#vrrp{}, Payload} | binary()
'802.1q'(Packet) -> {#'802.1q'{}, Payload} | binary()
null(Packet) -> {#null{}, Payload} | binary()
linux_cooked(Packet) -> {#linux_cooked{}, Payload} | binary()
gre(Packet) -> {#gre{}, Payload} | binary()
arp(Packet) -> {#arp{}, Payload} | binary()
ipv4(Packet) -> {#ipv4{}, Payload} | binary()
ipv6(Packet) -> {#ipv6{}, Payload} | binary()
tcp(Packet) -> {#tcp{}, Payload} | binary()
sctp(Packet) -> {#sctp{}, Payload} | binary()
udp(Packet) -> {#udp{}, Payload} | binary()
icmp(Packet) -> {#icmp{}, Payload} | binary()
icmp6(Packet) -> {#icmp6{}, Payload} | binary()
igmp(Packet) -> {#igmp{}, Payload} | binary()
mpls(Packet) -> {#mpls{}, Next, Payload}
lldp(Packet) -> {#lldp{}, Payload}
rarp(Packet) -> {#rarp{}, Payload}
'802.1x'(Packet) -> {#'802.1x'{}, Payload}
Types Packet = Header | binary()
Header = #ether{} | #null{} | #linux_cooked{} | #arp{} |
#ipv4{} | #ipv6{} | #tcp{} | #sctp{} | #udp{} |
#icmp{} | #icmp6{} | #igmp{} | #gre{} | #llc{} |
#vrrp{} | #'802.1q'{} | #lldp{} | #mpls{} | #rarp{} | #'802.1x'{}
Next = ipv4 | ipv6
makesum(Packet) -> integer()
Types Packet = IPv4_header | [IPv4_header, Header, Payload]
IPv4_header = #ipv4{}
Header = #tcp{} | #udp{}
Payload = binary()
Calculate the one's complement checksum of the packet.
When computing the checksum, the header sum field must be set
to 0:
Sum = pkt:makesum([IPv4, TCP#tcp{sum = 0}, Payload]).
For verifcation, the checksum can be compared to the value in
the header or:
0 = pkt:makesum([IPv4, TCP, Payload]).
Frame = << 224 , 105 , 149 , 59 , 163 , 24 , 0 , 22 , 182 , 181 , 62 , 198 , 8 , 0 , 69 , 0 , 0 , 54 , 2 , 108 , 64 ,
0 , 53 , 6 , 172 , 243 , 173 , 192 , 82 , 195 , 192 , 168 , 213 , 54 , 0 , 80 , 143 , 166 , 75 , 154 ,
212 , 181 , 116 , 33 , 53 , 92 , 128 , 24 , 0 , 126 , 60 , 199 , 0 , 0 , 1 , 1 , 8 , 10 , 92 , 104 , 96 ,
16 , 22 , 69 , 237 , 136 , 137 , 0 >>,
try pkt : decapsulate ( Frame ) of
[ # ether {}, # ipv4 { saddr = Saddr , daddr = Daddr },
# tcp { sport = Sport , dport = Dport }, _Payload ] ->
{{ Saddr , Sport }, { Daddr , Dport }}
catch
error : _ ->
ok % ignore invalid packets
end{ ok , [ # ether {}, IPv4 , # tcp { sum = Sum } = TCP , Payload ]} = pkt : decode ( ether , Frame ),
% Re-calculate the checksum and match against the checksum in the header
Sum = pkt : makesum ([ IPv4 , TCP # tcp { sum = 0 }, Payload ]),
% Or just verify the checksum
0 = pkt : makesum ([ IPv4 , TCP , Payload ]).イーサネットペイロードの最小サイズは46バイトです。 20バイトIPv4ヘッダーと20バイトTCPヘッダーとペイロードで構成されるTCP/IPパケットを含むイーサネットフレームは、6バイトでパッドでパッドされます。パケットの実際の長さを計算するには、IPv4ヘッダーの長さとヘッダーの長さの値とTCPヘッダーのオフセット値を使用します。
[ # ether {}, # ipv4 { len = Len , hl = HL }, # tcp { off = Off }, Payload ] = pkt : decapsulate ( Frame ),
Size = Len - ( HL * 4 ) - ( Off * 4 ),
<< Payload : Size / bytes >>.サポートRFC 2675（IPv6ジャンボグラム）
IPv6 AHおよびESP
ICMPv6
IGMP
wierlからのdlt_ieee802_11サポートでマージします
Gen_icmpのICMPv6コードでマージします
DLTS
