Translated from Yoram Kulbak and Danny Bickson "The Emule Protocol Specification" Translation: LZCX QQ: 402722857 Email: LZCX_CN@yahoo.com.cn For learning, please specify
6.2
Client server
TCP
news
This chapter describes messages transmitted with TCP between servers and clients.
6.2.1
log in
After the TCP connection is established, the first message sent to the server is a login message. The length of this message varies because it is based on the user's configuration, such as a user nickname. Why is the client's TCP port appears in the head of TCP, or is sent (2 times), which is not very clear.
name
Byte size
Defaults
Comment
Protocol (protocol)
1
0xe3
Size
(size)
4
Message size is in bytes, not including heads and sizes
Type
1
0x01
The value of the OP_LoginRequest operation code
User hash
(User Hash)
16
About the details of the user hash can be found in 1.4 knots
Client ID
(User ID)
4
0
The user ID sent in the first connection is usually zero. About the details of the user ID can be found in version 1.3
TCP Port
2
4662
The TCP port used by the client, configurable
Tag count
4
4
Number of tags followed in the message
Name tag
Variable
NA
The user's nickname (configurable in the software). This tag is a string tag, the tag name is an integer value 0x1
Version tag
8
0x3c
The EDONKEY version supported by the client. This label is an integer tag, the tag name is an integer value of 0x11
Port tag
8
4662
The TCP port used by the client. This tag is an integer label, the tag name is an integer value of 0x0F
Flags tag
8
0x01
This label is an integer label, the tag name is an integer value of 0x20
6.2.2
Server message
The server message is a variable length message. In different occasions, the first client login request is sent immediately by the server to the client. One server message can contain several messages, separated by a wrap operator ('/ R', '/ n' or both). With "Server Version", "Warning", "Error", and "[Emdynip:", there is a specific meaning of the client. Other messages are simply displayed to the user.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x38
OP_SERVERMESSAGE operation code value
Size
2
NA
The number of messages remaining bytes, does not include the currently described domain
Message
Variable
NA
A server message, separating
Special news
1,
Version - usually in successful connection I sent
2,
Error-
3,
WARNING - I usually send it when the server rejects the connection or the client is low ID
4,
Emdynip -
6.2.3 ID
change
The server sends an ID change message as a response to the login request message and the connection to the client has received the client. Message size is 14 or 10 bytes, depending on the selection of optional TCP connection bitmaps (TCP Connection Bitmap).
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x40
OP_IDCHANGE operation code value
Client ID
4
NA
Description of the client ID can be found in version 1.3
TCP Connection Bitmap
4
0x000000001
There is only 1 (LSB) meaningful and set it to identify the server support compression.
6.2.4
File provided
This message is used by the client to describe the available local files, allowing other clients to download. If the client is available, the file provides message immediately after the connection is established. This message is also sent when the client shared file list changes. Another usage of this message is to periodically send to the server and maintain the active state. If the server supports compression, the file provides (message) will be compressed. This message is not compressed when used as holding a status (no file compression and message size).
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x15
Op_offerfiles operate value
File count
4
NA
The number of documents described in it. No matter what is not more than 200. The server can also set a relatively low limit for this number.
Files
Variable
NA
Optional file list, a single entry format as follows
Single file entry format
The following table describes a single file entry. There can be a series of entries in a file providing message.
name
Byte size
Defaults
Comment
Hash Code
16
NA
The hash result (TBD specification) is performed on the file content. This hash uses the only identifier file, ignores the difference between the different clients.
Client ID
4
NA
Client ID, if the client has high ID, otherwise zero
Client port
2
0x15
The client TCP port number, if the client is low ID, zero
Tag count
4
NA
Number of labels below this domain
FILE Name Tag
Variable
NA
(The reference) file name. This tag is a string tag, the tag name is an integer value 0x1
FILE SIZE TAG
8
NA
(The required) file size, byte unit. This label is an integer tag, the label name is an integer value 0x2
File Type Tag
Variable
NA
(Optional) file type. One of the following: "Audio", "Video", "Image", "PRO" or "DOC". This tag is a string label, the tag name is an integer value 0x3
File Format Tag
Variable
NA
(Optional) File extension, lowercase. For example, "ZIP", "EXE". This tag is a string tag, the tag name is an integer value of 0x4
Media Length Tag
Variable
NA
(Optional) If the file is MP3, the song play time is played. The label is a string tag, the tag name is a string of "Length"
Media Bitrate Tag
TBD
NA
(Optional) If the file is MP3, the encoding bit rate is encoded. This tag is a whole tag, the tag name is "bitrate" string
Media Codec Tag
Variable
NA
(Optional, never send) If the file is a movie, the codec is encoded. This tag is a string tag, the label name is a string of "CODEC"
6.2.5
Get a list of servers
This message is sent from the client to the server immediately after successfully shaking hands. When the client is configured by requesting its current server to expand its EMULE server list, send the message. The message size is 6 bytes. name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x14
OP_SERVERSTATUS value of the opcode
6.2.6
Server status
Send it from the server to the client. This message contains information about the current number of users and files on the server. The information in the message is not only stored on the client, but also shows it to the user. This message is 14 bytes.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x34
User count
4
NA
The number of users currently logged in to the server
File count
4
NA
The number of files know the server
6.2.7
server list
Send it from the server to the client. This message contains information about expanding the list of client servers with additional EMULE servers. Message size varies (the number of servers sent).
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x32
The value of the OP_SERVERLIST operation code
ENTRY COUNT
1
NA
The number of servers described in this message
Server Entries
(Entry count) * 6
NA
Server descriptor entry, each entry size is 6 bytes, including 4 bytes IP addresses and 2 bytes TCP ports
6.2.8
Server identification
Send it from the server to the client. Contains Server Hash (TBD), server IP address, and TCP port (it is useful when connecting through a proxy), and servers describes information. Message size varies.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x41
OP_SERRERIDENT value
Hash
16
NA
The server's GUID (like to be used to debug)
Server IP
4
NA
Server IP address
Server port
4
NA
Server listening TCP port
Tag count
4
NA
Number of labels at the end of the message
Server Name Tag
Variable
NA
name of server. This tag is a string tag, the label name is an integer value of 0x1
Server Description Tag
Variable
NA
Server description strings. This tag is a string tag, the tag name is an integer value of 0xB
6.2.9
Search request
Send it from the client to the server. This message is used to search files through the user's search string. The message size is variable. Search strings can include Boolean conditions "and", "or", "not". The user can specify the type and size of the required files, or set a valid threshold (eg, display at least five other client valid results).
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x16
OP_SearchRequest operation code value
PARSED SEARCH STRING
Variable
NA
Analyze search string format, below
FILE TYPE CONSTRAINT
Variable
NA
Optional. String condition. The string value is "Audio", "Video", "Pro", or "Image". Type domain is 3 bytes: 0x1 0x0 0x3
MIN SIZE CONSTRAINT
Variable
NA
Optional. Integer conditions. The file size unit is M. Type domain is 4 bytes: 0x1 0x1 0x0 0x2
Max Size Constraint
Variable
NA
Optional. Integer conditions. The file size unit is M. Type domain is 4 bytes: 0x2 0x1 0x0 0x2
Availability Constraint
Variable
NA
Optional. Integer conditions. Set a lower limit on the number of clients that provide the search file. Type domain is 4 bytes: 0x1 0x1 0x0 0x15
Filename Extension Constrain
Variable
NA
Optional. String condition. Type domain is 3 bytes: 0x1 0x0 0x3
Resolution search string format
The parsed search string encodes a binary tree with a Boolean operator 'and', 'or' NOT 'and the string operand. The tree is encoded in advance. The operator encodes 2 bytes integer, 0x0 corresponds to 'and',
0x100 corresponds to 'or', 0x200 corresponds to 'NOT'. The string is encoded in TLV format, where the type of domain is 0x1, the length of the length is 2 byte integers. Note that when the search string is a word, it is encoded as a single string operand (no operator). The subsequent EMULE version encodes a string search expression of only the "AND" operator, instead of "AND" with spaces, so that the server's search string resolution, divide a statement into a series of "AND" operator separation Words.
Optional conditional format
The condition is a sequence of entries. Each entry begins with the "AND" descriptor (2 bytes 0x00), followed by the encoded condition. Thus, the entire search line format is the <"Search String" AND condition 1 AND condition 2, etc., as shown in the example below. The coding conditions are divided into 3 domains:
1.
Type-single byte, description is a string condition (0x2) or integer conditions (0x3)
2.
Value - either the type length encoded string, or 4-byte integer value
3.
Type - 3 or 4 bytes, description conditions (see the main table above)
6.2.10
search results
The message sent from the server to the client as a response to the search request. This message is usually compressed. Message size varies.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x16
OP_SearchResult the value of the opcode
Result Count
4
NA
Number of search results in the message
Result List
Variable
NA
Search results list
Search results list form form
The following table describes a format of a search results list item. Each search result contains a hash, this hash uniquely identifies the file, along with the details of other emule clients with this file. There are also several tags describe file properties. The label list is as follows. Note that most of the labels are optional, and their order is not guaranteed. The label coding rules are described in detail in this chapter.
name
Byte size
Defaults
Comment
File Hash
16
NA
Hash value, the only identity certificate used to file
Client ID
4
NA
Idle of the emule client with the file
Client port
2
NA
TCP port with client client
Tag count
4
NA
The number of descriptors below
Tag List
Variable
NA
Descriptor tag list
6.2.11
Get the source
This message is sent from the client to the server, for the file request source (other client). The message size is 22 bytes.
name
Byte size
Defaults
Comment
Protocol1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x19
Op_getsourcers
File Hash
16
NA
Hash requesting file
6.2.12
Source found
This message is sent from the server to the client with a source of requesting file (other client). Message size varies.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x42
Op_foundsourcers operated value
File Hash
16
NA
Hash requesting file
Sources country
1
NA
Number of sides of the message
List of sources
Variable
NA
Source list
Source list item format
The following table describes the format of the source list item. Each source contains details of the EMULE client with the file.
name
Byte size
Defaults
Comment
Client ID
4
NA
Emule client with this file
Client port
2
NA
The TCP port of the EMULE client with this file
6.2.13
Callback request
This message is sent from the client to the server, requiring other client callbacks -, for example, the client connected to the request. With high ID, you want to connect to a low ID client (see Section 2.4) to send the message. The message size is 10 bytes.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x1c
OP_CALLBACKREQUEST operation code value
Client ID
4
NA
Request callback customer ID
6.2.14
Request callback
This message is sent from the server to the client, indicating that the client requiring the received client to connect it. When the received client is low ID (see Section 2.4), the message is sent. The message size is 12 bytes. The received client attempts to connect this IP and port specified by the callback request package.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x35
Op_callbackRequested operator value
Client IP
4
NA
Request call your client IP
Client TCP Port
2
NA
TCP port listens on the client
6.2.15
Callback failure
This message is sent from the server to the client, indicating that the client's callback request failed. The message size is 6 bytes. The received client puts this message log and discards it.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x36
OP_CALLBACK_FAILED value
6.2.16
Message is rejected
This message is sent from the server to the client, indicating the last command that the server rejects the client. The message is 6 bytes. The received client puts this message log and discards it.
name
Byte size
Defaults
Comment
Protocol
1
0xe3
Size
4
Message size is in bytes, not including heads and sizes
Type
1
0x05
OP_REJECT value of the opcode
