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
# If you want to change PREFIX, do not just edit it below. The changed
# value wont get passed on to recursive make calls. You should instead
# override the variable on the command like:
#
# % make PREFIX=/opt/ install
export PREFIX=/usr/local
PYTHON=python
$(eval HGROOT := $(shell pwd))
HGPYTHONS ?= $(HGROOT)/build/pythons
PURE=
PYFILES:=$(shell find mercurial hgext doc -name '*.py')
DOCFILES=mercurial/help/*.txt
export LANGUAGE=C
export LC_ALL=C
TESTFLAGS ?= $(shell echo $$HGTESTFLAGS)
OSXVERSIONFLAGS ?= $(shell echo $$OSXVERSIONFLAGS)
# Set this to e.g. "mingw32" to use a non-default compiler.
COMPILER=
COMPILERFLAG_tmp_ =
COMPILERFLAG_tmp_${COMPILER} ?= -c $(COMPILER)
COMPILERFLAG=${COMPILERFLAG_tmp_${COMPILER}}
help:
@echo 'Commonly used make targets:'
@echo ' all - build program and documentation'
@echo ' install - install program and man pages to $$PREFIX ($(PREFIX))'
@echo ' install-home - install with setup.py install --home=$$HOME ($(HOME))'
@echo ' local - build for inplace usage'
@echo ' tests - run all tests in the automatic test suite'
@echo ' test-foo - run only specified tests (e.g. test-merge1.t)'
@echo ' dist - run all tests and create a source tarball in dist/'
@echo ' clean - remove files created by other targets'
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@echo
@echo 'Example for a system-wide installation under /usr/local:'
@echo ' make all && su -c "make install" && hg version'
@echo
@echo 'Example for a local installation (usable in this directory):'
@echo ' make local && ./hg version'
all: build doc
local:
$(PYTHON) setup.py $(PURE) \
build_py -c -d . \
build_ext $(COMPILERFLAG) -i \
build_hgexe $(COMPILERFLAG) -i \
build_mo
env HGRCPATH= $(PYTHON) hg version
build:
$(PYTHON) setup.py $(PURE) build $(COMPILERFLAG)
wheel:
FORCE_SETUPTOOLS=1 $(PYTHON) setup.py $(PURE) bdist_wheel $(COMPILERFLAG)
doc:
$(MAKE) -C doc
cleanbutpackages:
-$(PYTHON) setup.py clean --all # ignore errors from this command
find contrib doc hgext hgext3rd i18n mercurial tests hgdemandimport \
\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
rm -f mercurial/__modulepolicy__.py
if test -d .hg; then rm -f mercurial/__version__.py; fi
rm -rf build mercurial/locale
$(MAKE) -C doc clean
$(MAKE) -C contrib/chg distclean
clean: cleanbutpackages
rm -rf packages
install: install-bin install-doc
install-bin: build
$(PYTHON) setup.py $(PURE) install --root="$(DESTDIR)/" --prefix="$(PREFIX)" --force
install-doc: doc
cd doc && $(MAKE) $(MFLAGS) install
install-home: install-home-bin install-home-doc
install-home-bin: build
$(PYTHON) setup.py $(PURE) install --home="$(HOME)" --prefix="" --force
install-home-doc: doc
cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install
MANIFEST-doc:
$(MAKE) -C doc MANIFEST
MANIFEST.in: MANIFEST-doc
hg manifest | sed -e 's/^/include /' > MANIFEST.in
echo include mercurial/__version__.py >> MANIFEST.in
sed -e 's/^/include /' < doc/MANIFEST >> MANIFEST.in
dist: tests dist-notests
dist-notests: doc MANIFEST.in
TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist
check: tests
tests:
cd tests && $(PYTHON) run-tests.py $(TESTFLAGS)
test-%:
cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@
testpy-%:
@echo Looking for Python $* in $(HGPYTHONS)
[ -e $(HGPYTHONS)/$*/bin/python ] || ( \
cd $$(mktemp --directory --tmpdir) && \
$(MAKE) -f $(HGROOT)/contrib/Makefile.python PYTHONVER=$* PREFIX=$(HGPYTHONS)/$* python )
cd tests && $(HGPYTHONS)/$*/bin/python run-tests.py $(TESTFLAGS)
check-code:
hg manifest | xargs python contrib/check-code.py
format-c:
clang-format --style file -i \
`hg files 'set:(**.c or **.cc or **.h) and not "listfile:contrib/clang-format-blacklist"'`
update-pot: i18n/hg.pot
i18n/hg.pot: $(PYFILES) $(DOCFILES) i18n/posplit i18n/hggettext
$(PYTHON) i18n/hggettext mercurial/commands.py \
hgext/*.py hgext/*/__init__.py \
mercurial/fileset.py mercurial/revset.py \
mercurial/templatefilters.py mercurial/templatekw.py \
mercurial/templater.py \
mercurial/filemerge.py \
mercurial/hgweb/webcommands.py \
mercurial/util.py \
$(DOCFILES) > i18n/hg.pot.tmp
# All strings marked for translation in Mercurial contain
# ASCII characters only. But some files contain string
# literals like this '\037\213'. xgettext thinks it has to
# parse them even though they are not marked for translation.
# Extracting with an explicit encoding of ISO-8859-1 will make
# xgettext "parse" and ignore them.
echo $(PYFILES) | xargs \
xgettext --package-name "Mercurial" \
--msgid-bugs-address "<mercurial-devel@mercurial-scm.org>" \
--copyright-holder "Matt Mackall <mpm@selenic.com> and others" \
--from-code ISO-8859-1 --join --sort-by-file --add-comments=i18n: \
-d hg -p i18n -o hg.pot.tmp
$(PYTHON) i18n/posplit i18n/hg.pot.tmp
# The target file is not created before the last step. So it never is in
# an intermediate state.
mv -f i18n/hg.pot.tmp i18n/hg.pot
%.po: i18n/hg.pot
# work on a temporary copy for never having a half completed target
cp $@ $@.tmp
msgmerge --no-location --update $@.tmp $^
mv -f $@.tmp $@
# Packaging targets
osx:
rm -rf build/mercurial
/usr/bin/python2.7 setup.py install --optimize=1 \
--root=build/mercurial/ --prefix=/usr/local/ \
--install-lib=/Library/Python/2.7/site-packages/
make -C doc all install DESTDIR="$(PWD)/build/mercurial/"
# Place a bogon .DS_Store file in the target dir so we can be
# sure it doesn't get included in the final package.
touch build/mercurial/.DS_Store
# install zsh completions - this location appears to be
# searched by default as of macOS Sierra.
install -d build/mercurial/usr/local/share/zsh/site-functions/
install -m 0644 contrib/zsh_completion build/mercurial/usr/local/share/zsh/site-functions/_hg
# install bash completions - there doesn't appear to be a
# place that's searched by default for bash, so we'll follow
# the lead of Apple's git install and just put it in a
# location of our own.
install -d build/mercurial/usr/local/hg/contrib/
install -m 0644 contrib/bash_completion build/mercurial/usr/local/hg/contrib/hg-completion.bash
make -C contrib/chg \
HGPATH=/usr/local/bin/hg \
PYTHON=/usr/bin/python2.7 \
HGEXTDIR=/Library/Python/2.7/site-packages/hgext \
DESTDIR=../../build/mercurial \
PREFIX=/usr/local \
clean install
mkdir -p $${OUTPUTDIR:-dist}
HGVER=$$(python contrib/genosxversion.py $(OSXVERSIONFLAGS) build/mercurial/Library/Python/2.7/site-packages/mercurial/__version__.py) && \
OSXVER=$$(sw_vers -productVersion | cut -d. -f1,2) && \
pkgbuild --filter \\.DS_Store --root build/mercurial/ \
--identifier org.mercurial-scm.mercurial \
--version "$${HGVER}" \
build/mercurial.pkg && \
productbuild --distribution contrib/macosx/distribution.xml \
--package-path build/ \
--version "$${HGVER}" \
--resources contrib/macosx/ \
"$${OUTPUTDIR:-dist/}"/Mercurial-"$${HGVER}"-macosx"$${OSXVER}".pkg
deb:
contrib/builddeb
ppa:
contrib/builddeb --source-only
contrib/docker/debian-%: contrib/docker/debian.template
sed "s/__CODENAME__/$*/" $< > $@
docker-debian-jessie: contrib/docker/debian-jessie
mkdir -p packages/debian-jessie
contrib/dockerdeb debian jessie
docker-debian-stretch: contrib/docker/debian-stretch
mkdir -p packages/debian-stretch
contrib/dockerdeb debian stretch
contrib/docker/ubuntu-%: contrib/docker/ubuntu.template
sed "s/__CODENAME__/$*/" $< > $@
docker-ubuntu-trusty: contrib/docker/ubuntu-trusty
contrib/dockerdeb ubuntu trusty
docker-ubuntu-trusty-ppa: contrib/docker/ubuntu-trusty
contrib/dockerdeb ubuntu trusty --source-only
docker-ubuntu-xenial: contrib/docker/ubuntu-xenial
contrib/dockerdeb ubuntu xenial
docker-ubuntu-xenial-ppa: contrib/docker/ubuntu-xenial
contrib/dockerdeb ubuntu xenial --source-only
docker-ubuntu-artful: contrib/docker/ubuntu-artful
contrib/dockerdeb ubuntu artful
docker-ubuntu-artful-ppa: contrib/docker/ubuntu-artful
contrib/dockerdeb ubuntu artful --source-only
fedora20:
mkdir -p packages/fedora20
contrib/buildrpm
cp rpmbuild/RPMS/*/* packages/fedora20
cp rpmbuild/SRPMS/* packages/fedora20
rm -rf rpmbuild
docker-fedora20:
mkdir -p packages/fedora20
contrib/dockerrpm fedora20
fedora21:
mkdir -p packages/fedora21
contrib/buildrpm
cp rpmbuild/RPMS/*/* packages/fedora21
cp rpmbuild/SRPMS/* packages/fedora21
rm -rf rpmbuild
docker-fedora21:
mkdir -p packages/fedora21
contrib/dockerrpm fedora21
centos5:
mkdir -p packages/centos5
contrib/buildrpm --withpython
cp rpmbuild/RPMS/*/* packages/centos5
cp rpmbuild/SRPMS/* packages/centos5
docker-centos5:
mkdir -p packages/centos5
contrib/dockerrpm centos5 --withpython
centos6:
mkdir -p packages/centos6
contrib/buildrpm --withpython
cp rpmbuild/RPMS/*/* packages/centos6
cp rpmbuild/SRPMS/* packages/centos6
docker-centos6:
mkdir -p packages/centos6
contrib/dockerrpm centos6 --withpython
centos7:
mkdir -p packages/centos7
contrib/buildrpm
cp rpmbuild/RPMS/*/* packages/centos7
cp rpmbuild/SRPMS/* packages/centos7
docker-centos7:
mkdir -p packages/centos7
contrib/dockerrpm centos7
linux-wheels: linux-wheels-x86_64 linux-wheels-i686
linux-wheels-x86_64:
docker run -e "HGTEST_JOBS=$(shell nproc)" --rm -ti -v `pwd`:/src quay.io/pypa/manylinux1_x86_64 /src/contrib/build-linux-wheels.sh
linux-wheels-i686:
docker run -e "HGTEST_JOBS=$(shell nproc)" --rm -ti -v `pwd`:/src quay.io/pypa/manylinux1_i686 linux32 /src/contrib/build-linux-wheels.sh
.PHONY: help all local build doc cleanbutpackages clean install install-bin \
install-doc install-home install-home-bin install-home-doc \
dist dist-notests check tests check-code format-c update-pot \
osx deb ppa docker-debian-jessie docker-debian-stretch \
docker-ubuntu-trusty docker-ubuntu-trusty-ppa \
docker-ubuntu-xenial docker-ubuntu-xenial-ppa \
docker-ubuntu-artful docker-ubuntu-artful-ppa \
fedora20 docker-fedora20 fedora21 docker-fedora21 \
centos5 docker-centos5 centos6 docker-centos6 centos7 docker-centos7 \
linux-wheels