view tests/test-ssh-proto.t @ 35976:48a3a9283f09

sshpeer: initial definition and implementation of new SSH protocol

The existing SSH protocol has several design flaws. Future commits
will elaborate on these flaws as new features are introduced
to combat these flaws. For now, hopefully you can take me for my
word that a ground up rewrite of the SSH protocol is needed.

This commit lays the foundation for a new SSH protocol by defining
a mechanism to upgrade the SSH transport channel away from the
default (version 1) protocol to something modern (which we'll call
"version 2" for now).

This upgrade process is detailed in the internals documentation
for the wire protocol. The gist of it is the client sends a
request line preceding the "hello" command/line which basically
says "I'm requesting an upgrade: here's what I support." If the
server recognizes that line, it processes the upgrade request and
the transport channel is switched to use the new version of the
protocol. If not, it sends an empty response, which is how all
Mercurial SSH servers from the beginning of time reacted to unknown
commands. The upgrade request is effectively ignored and the client
continues to use the existing version of the protocol as if nothing
happened.

The new version of the SSH protocol is completely identical to
version 1 aside from the upgrade dance and the bytes that follow.
The immediate bytes that follow the protocol switch are defined to
be a length framed "capabilities: " line containing the remote's
advertised capabilities. In reality, this looks very similar to
what the "hello" response would look like. But it will evolve
quickly.

The methodology by which the protocol will evolve is important.

I'm not going to introduce the new protocol all at once. That would
likely lead to endless bike shedding and forward progress would
stall. Instead, I intend to tricle out new features and diversions
from the existing protocol in small, incremental changes.

To support the gradual evolution of the protocol, the on-the-wire
advertised protocol name contains an "exp" to denote "experimental"
and a 4 digit field to capture the sub-version of the protocol.
Whenever we make a BC change to the wire protocol, we can increment
this version and lock out all older clients because it will appear
as a completely different protocol version. This means we can incur
as many breaking changes as we want. We don't have to commit to
supporting any one feature or idea for a long period of time. We
can even evolve the handshake mechanism, because that is defined
as being an implementation detail of the negotiated protocol version!
Hopefully this lowers the barrier to accepting changes to the
protocol and for experimenting with "radical" ideas during its
development.

In core, sshpeer received most of the attention. We haven't even
implemented the server bits for the new protocol in core yet.
Instead, we add very primitive support to our test server, mainly
just to exercise the added code paths in sshpeer.

Differential Revision: https://phab.mercurial-scm.org/D2061

# no-check-commit because of required foo_bar naming

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > ssh = $PYTHON "$TESTDIR/dummyssh"
  > [devel]
  > debug.peer-request = true
  > [extensions]
  > sshprotoext = $TESTDIR/sshprotoext.py
  > EOF

  $ hg init server
  $ cd server
  $ echo 0 > foo
  $ hg -q add foo
  $ hg commit -m initial
  $ cd ..

Test a normal behaving server, for sanity

  $ hg --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: 384
  remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  remote: 1
  url: ssh://user@dummy/server
  local: no
  pushable: yes

Server should answer the "hello" command in isolation

  $ hg -R server serve --stdio << EOF
  > hello
  > EOF
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN

>=0.9.1 clients send a "hello" + "between" for the null range as part of handshake.
Server should reply with capabilities and should send "1\n\n" as a successful
reply with empty response to the "between".

  $ hg -R server serve --stdio << EOF
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

SSH banner is not printed by default, ignored by clients

  $ SSHSERVERMODE=banner hg debugpeer ssh://user@dummy/server
  url: ssh://user@dummy/server
  local: no
  pushable: yes

--debug will print the banner

  $ SSHSERVERMODE=banner hg --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: banner: line 0
  remote: banner: line 1
  remote: banner: line 2
  remote: banner: line 3
  remote: banner: line 4
  remote: banner: line 5
  remote: banner: line 6
  remote: banner: line 7
  remote: banner: line 8
  remote: banner: line 9
  remote: 384
  remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  remote: 1
  url: ssh://user@dummy/server
  local: no
  pushable: yes

And test the banner with the raw protocol

  $ SSHSERVERMODE=banner hg -R server serve --stdio << EOF
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  banner: line 0
  banner: line 1
  banner: line 2
  banner: line 3
  banner: line 4
  banner: line 5
  banner: line 6
  banner: line 7
  banner: line 8
  banner: line 9
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

Connecting to a <0.9.1 server that doesn't support the hello command.
The client should refuse, as we dropped support for connecting to such
servers.

  $ SSHSERVERMODE=no-hello hg --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: 0
  remote: 1
  abort: no suitable response from remote hg!
  [255]

Sending an unknown command to the server results in an empty response to that command

  $ hg -R server serve --stdio << EOF
  > pre-hello
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg --config sshpeer.mode=extra-handshake-commands --config sshpeer.handshake-mode=pre-no-args --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  sending no-args command
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: 0
  remote: 384
  remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  remote: 1
  url: ssh://user@dummy/server
  local: no
  pushable: yes

Send multiple unknown commands before hello

  $ hg -R server serve --stdio << EOF
  > unknown1
  > unknown2
  > unknown3
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg --config sshpeer.mode=extra-handshake-commands --config sshpeer.handshake-mode=pre-multiple-no-args --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  sending unknown1 command
  sending unknown2 command
  sending unknown3 command
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: 0
  remote: 0
  remote: 0
  remote: 384
  remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  remote: 1
  url: ssh://user@dummy/server
  local: no
  pushable: yes

Send an unknown command before hello that has arguments

  $ hg -R server serve --stdio << EOF
  > with-args
  > foo 13
  > value for foo
  > bar 13
  > value for bar
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  0
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

Send an unknown command having an argument that looks numeric

  $ hg -R server serve --stdio << EOF
  > unknown
  > foo 1
  > 0
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg -R server serve --stdio << EOF
  > unknown
  > foo 1
  > 1
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

When sending a dict argument value, it is serialized to
"<arg> <item count>" followed by "<key> <len>\n<value>" for each item
in the dict.

Dictionary value for unknown command

  $ hg -R server serve --stdio << EOF
  > unknown
  > dict 3
  > key1 3
  > foo
  > key2 3
  > bar
  > key3 3
  > baz
  > hello
  > EOF
  0
  0
  0
  0
  0
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN

Incomplete dictionary send

  $ hg -R server serve --stdio << EOF
  > unknown
  > dict 3
  > key1 3
  > foo
  > EOF
  0
  0
  0
  0

Incomplete value send

  $ hg -R server serve --stdio << EOF
  > unknown
  > dict 3
  > key1 3
  > fo
  > EOF
  0
  0
  0
  0

Send a command line with spaces

  $ hg -R server serve --stdio << EOF
  > unknown withspace
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg -R server serve --stdio << EOF
  > unknown with multiple spaces
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg -R server serve --stdio << EOF
  > unknown with spaces
  > key 10
  > some value
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  0
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

Send an unknown command after the "between"

  $ hg -R server serve --stdio << EOF
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000unknown
  > EOF
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  
  0

And one with arguments

  $ hg -R server serve --stdio << EOF
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000unknown
  > foo 5
  > value
  > bar 3
  > baz
  > EOF
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  
  0
  0
  0
  0
  0

Send an upgrade request to a server that doesn't support that command

  $ hg -R server serve --stdio << EOF
  > upgrade 2e82ab3f-9ce3-4b4e-8f8c-6fd1c0e9e23a proto=irrelevant1%2Cirrelevant2
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  0
  384
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  1
  

  $ hg --config experimental.sshpeer.advertise-v2=true --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  sending upgrade request: * proto=exp-ssh-v2-0001 (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  remote: 0
  remote: 384
  remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN
  remote: 1
  url: ssh://user@dummy/server
  local: no
  pushable: yes

Send an upgrade request to a server that supports upgrade

  $ SSHSERVERMODE=upgradev2 hg -R server serve --stdio << EOF
  > upgrade this-is-some-token proto=exp-ssh-v2-0001
  > hello
  > between
  > pairs 81
  > 0000000000000000000000000000000000000000-0000000000000000000000000000000000000000
  > EOF
  upgraded this-is-some-token exp-ssh-v2-0001
  383
  capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch streamreqs=generaldelta,revlogv1 $USUAL_BUNDLE2_CAPS_SERVER$ unbundle=HG10GZ,HG10BZ,HG10UN

  $ SSHSERVERMODE=upgradev2 hg --config experimental.sshpeer.advertise-v2=true --debug debugpeer ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  sending upgrade request: * proto=exp-ssh-v2-0001 (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  protocol upgraded to exp-ssh-v2-0001
  url: ssh://user@dummy/server
  local: no
  pushable: yes

Verify the peer has capabilities

  $ SSHSERVERMODE=upgradev2 hg --config experimental.sshpeer.advertise-v2=true --debug debugcapabilities ssh://user@dummy/server
  running * "*/tests/dummyssh" 'user@dummy' 'hg -R server serve --stdio' (glob)
  sending upgrade request: * proto=exp-ssh-v2-0001 (glob)
  devel-peer-request: hello
  sending hello command
  devel-peer-request: between
  devel-peer-request:   pairs: 81 bytes
  sending between command
  protocol upgraded to exp-ssh-v2-0001
  Main capabilities:
    batch
    branchmap
    $USUAL_BUNDLE2_CAPS_SERVER$
    changegroupsubset
    getbundle
    known
    lookup
    pushkey
    streamreqs=generaldelta,revlogv1
    unbundle=HG10GZ,HG10BZ,HG10UN
    unbundlehash
  Bundle2 capabilities:
    HG20
    bookmarks
    changegroup
      01
      02
    digests
      md5
      sha1
      sha512
    error
      abort
      unsupportedcontent
      pushraced
      pushkey
    hgtagsfnodes
    listkeys
    phases
      heads
    pushkey
    remote-changegroup
      http
      https