# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

SSL's Buffers: enumerated and explained.

---------------------------------------------------------------------------
incoming:

gs = ss->gather
hs = ss->ssl3->hs

gs->inbuf   SSL3 only: incoming (encrypted) ssl records are placed here,
        and then decrypted (or copied) to gs->buf.

gs->buf     SSL2: incoming SSL records are put here, and then decrypted
        in place.
        SSL3: ssl3_HandleHandshake puts decrypted ssl records here.

hs.msg_body (SSL3 only) When an incoming handshake message spans more
        than one ssl record, the first part(s) of it are accumulated
        here until it all arrives.

hs.msgState (SSL3 only) an alternative set of pointers/lengths for gs->buf.
        Used only when a handleHandshake function returns SECWouldBlock.
        ssl3_HandleHandshake remembers how far it previously got by
        using these pointers instead of gs->buf when it is called
        after a previous SECWouldBlock return.

---------------------------------------------------------------------------
outgoing:

sec = ss->sec
ci  = ss->sec->ci   /* connect info */

ci->sendBuf Outgoing handshake messages are appended to this buffer.
        This buffer will then be sent as a single SSL record.

sec->writeBuf   outgoing ssl records are constructed here and encrypted in
        place before being written or copied to pendingBuf.

ss->pendingBuf  contains outgoing ciphertext that was saved after a write
        attempt to the socket failed, e.g. EWouldBlock.
        Generally empty with blocking sockets (should be no incomplete
        writes).

ss->saveBuf Used only by socks code.  Intended to be used to buffer
        outgoing data until a socks handshake completes.  However,
        this buffer is always empty.  There is no code to put
        anything into it.

---------------------------------------------------------------------------

SECWouldBlock means that the function cannot make progress because it is
waiting for some event OTHER THAN socket I/O completion (e.g. waiting for
user dialog to finish).  It is not the same as EWOULDBLOCK.

---------------------------------------------------------------------------

Rank (order) of locks

recvLock ->\ firstHandshake -> recvbuf -> ssl3Handshake -> xmitbuf -> "spec"
sendLock ->/

crypto and hash Data that must be protected while turning plaintext into
ciphertext:

SSL2:   (in ssl2_Send*)
    sec->hash*
    sec->hashcx     (ptr and data)
    sec->enc
    sec->writecx*   (ptr and content)
    sec->sendSecret*(ptr and content)
    sec->sendSequence       locked by xmitBufLock
    sec->blockSize
    sec->writeBuf*  (ptr & content) locked by xmitBufLock
    "in"                locked by xmitBufLock

SSl3:   (in ssl3_SendPlainText)
    ss->ssl3            (the pointer)
    ss->ssl3->current_write*    (the pointer and the data in the spec
                     and any data referenced by the spec.

    ss->sec->isServer
    ss->sec->writebuf* (ptr & content) locked by xmitBufLock
    "buf"                  locked by xmitBufLock

crypto and hash data that must be protected while turning ciphertext into
plaintext:

SSL2:   (in ssl2_GatherData)
    gs->*               (locked by recvBufLock )
    sec->dec
    sec->readcx
    sec->hash*      (ptr and data)
    sec->hashcx         (ptr and data)

SSL3:   (in ssl3_HandleRecord )
    ssl3->current_read* (the pointer and all data refernced)
    ss->sec->isServer


Data that must be protected while being used by a "writer":

ss->pendingBuf.*
ss->saveBuf.*       (which is dead)

in ssl3_sendPlainText

ss->ssl3->current_write-> (spec)
ss->sec->writeBuf.*
ss->sec->isServer

in SendBlock

ss->sec->hash->length
ss->sec->blockSize
ss->sec->writeBuf.*
ss->sec->sendSecret
ss->sec->sendSequence
ss->sec->writecx    *
ss->pendingBuf

--------------------------------------------------------------------------

Data variables (not const) protected by the "sslGlobalDataLock".
Note, this really should be a reader/writer lock.

allowedByPolicy     sslcon.c
maybeAllowedByPolicy    sslcon.c
chosenPreference    sslcon.c
policyWasSet        sslcon.c

cipherSuites[]      ssl3con.c
