Subversion Repositories planix.SVN

protocol version id

both client and server send '\n' terminated ascii of the form

venti-<versions>-<software>


<software> = is a software id which is ignored but may be useful for debugging

If the server and client have the same version number then this
version is used.  Otherwise backup to the greatest common
major version number, e.g. 1.00 2.00 etc.  If no version in
common then abort.  The idea is both client and server should
support a continusous range of major versions.  The minor version
numbers are used for development purposes.

After protocol negotiation switch to binary format

all numbers sent big endian

strings are sent with 2 byte length without nulls and in utf-8 max size of 1K

RPC protocol

header 
        op[1]   byte op
        tid[2]  transation id

client manages the tid space.  Until session is established tid must equal 0.
i.e. only one outstanding op.

CipherStrength
        None,
        Auth,
        Weak,
        Strong
CipherAlgorithms
        None
        SSL3
        TLS1
CompressionAlgorithms
        None
        Deflate
        Thwack?

BlockTypes
        Root
        Pointer
        Data

==============================================

TPing
RPing

RError
        error: string

THello
        version:string;         know to be supported by both
        uid: string
        uhash[20]               use for cipher boot strapping
        cipherstrength[1]
        ncipher[1];
        cipher[ncipher];
        ncompressor[1];
        compressor[ncompressor];
RHello
        sid: string
        shash[20];              use for cipher bott strapping
        cipher[1];
        compressor[1];

use srp style authentication
        g=2
        N is safe prime 1024 bits - find a good prime!

        x = H("venti" H(sid) H(uid) H(password))
        v = g^x
        a = random
        b = random
        B = (v + g^b)
        A = g^a
        u = first four bytes of H(B)
        S = (B - g^x) ^ (a + u*x) = (A * v^u) ^ b
        K = H(S)
        M1 = H(H(versions) H(THello) H(RHello) A B K)
        M2 = H(A M1 K)

TAuth0
        A[128]
RAuth0
        B[128]
TAuth1
        M1[20]
RAuth1
        M2[20]

push cipher
push compression

TWrite
        length[2] max 56*1024
        type[1]
        data[length]
RWrite
        hash[20]

TRead
        hash[20]
        type[1]
        length[2]
RRead
        length[2]
        data[length]

============================================================

simplified access when trusting the server
reduces network bandwidth since pointer blocks are not
sent to the client - can also enable permission checking

RReadRoot
        root[20]
TReadRoot
        name: string
        type: string
        blocksize[2]
        nblock[8]
        time[4]
        uid: string;
        gid: string

RReadData
        root[20]
        block[8]
        length[2]
TReadData
        length[2]
        collision[1]
        data[length]

==============================================

maybe some clients should be required to navigate to block via root nodes.
This would enable permission checking via access to the root node.

RTagOpen
        tag[2]
        root[20]
TTagOpen

QTagRead
        tag[2]
        type[1]
        length[2]
RTagRead
        length[2]
        data[length]
        
QTagWalkRead
        tag[2]
        ntag[2]         can reuse a tag to do an implict clunk
        index[2]
        type[1]
        length[2]
RTagWalkRead
        length[2]
        data[length]

RTagClunk
        tag[2]
TTagClunk

============================

Types of blocks

Data

Root
        name[128]
        type[128]
        score[20]       - DirBlock

Pointer
        score[20]*      the number of hashes can be less than fanout when the
                        tree is not full
DirBlock
        DirEntry[32]*

DirEntry        
        pointersize[2]  - pointer block size
        datasize[2]     - data blocks size
        flag[1]         directory
        size[7]         in bytes - determines pointer depth - intermidate truncated block count as full
        score[20]       root of pointer blocks or data block 

============================

mode flags
        (1<<0)  ModeOtherExec
        (1<<1)  ModeOtherWrite
        (1<<2)  ModeOtherRead
        (1<<3)  ModeGroupExec
        (1<<4)  ModeGroupWrite
        (1<<5)  ModeGroupRead
        (1<<6)  ModeOwnerExec
        (1<<7)  ModeOwnerWrite
        (1<<8)  ModeOwnerRead
        (1<<9)  ModeSticky
        (1<<10) ModeSetUid
        (1<<11) ModeSetGid
        (1<<12) ModeAppend
        (1<<13) ModeExclusive
        (1<<14) ModeLink
        (1<<15) ModeDir - duplicates dir entry
        (1<<16) ModeHidden
        (1<<17) ModeSystem
        (1<<18) ModeArchive
        (1<<19) ModeTemporary
        (1<<18) ModeCompressed
        (1<<19) ModeEncrypted

extraType
        2       Plan9
        version[4]
        muid: string

        3 NT Time
        createTime[8];
        modifyTime[8];
        accessTime[8]
        

MetaEntry
        name: string    /* must be first */
        direntry[4]

        id[8]

        uid: string
        gui: string
        mtime[4]
        ctime[4]
        atime[4]
        
        mode[4] 
        
        extratype;
        extrasize[2]
        extra:[nextra]

MetaEntry Block
        magic[4]
        size[2]
        free[2] - used to determine if work compacting
        maxindex[2] - size of index table in bytes
        nindex[2]
        index[2*nindex]

per OS directory entries?

inode...