server.py: handle (throw away) ECONNREFUSED from the DNS server.

This might happen occasionally on a flakey network.  Reported by Ed Maste.

.gitignore

@@ -1,3 +1,6 @@
 *.pyc
 *~
 *.8
+/.do_built
+/.do_built.dir
+/.redo

Makefile

@@ -1,19 +1,10 @@
-PANDOC:=$(shell \
-	if pandoc </dev/null 2>/dev/null; then \
-		echo pandoc; \
-	else \
-		echo "Warning: pandoc not installed; can't generate manpages." >&2; \
-		echo '@echo Skipping: pandoc'; \
-	fi)
+all:
 
-default: all
+Makefile:
+	@
 
-all: sshuttle.8
+%: FORCE
+	+./do $@
 
-sshuttle.8: sshuttle.md
+.PHONY: FORCE
 
-%.8: %.md
-	$(PANDOC) -s -r markdown -w man -o $@ $<
-
-clean:
-	rm -f *~ */*~ .*~ */.*~ *.8 *.tmp */*.tmp *.pyc */*.pyc

README.md

@@ -1,3 +1,14 @@
+
+WARNING:
+On MacOS 10.6 (at least up to 10.6.6), your network will
+stop responding about 10 minutes after the first time you
+start sshuttle, because of a MacOS kernel bug relating to
+arp and the net.inet.ip.scopedroute sysctl.  To fix it,
+just switch your wireless off and on. Sshuttle makes the
+kernel setting it changes permanent, so this won't happen
+again, even after a reboot.
+
+
 sshuttle: where transparent proxy meets VPN meets ssh
 =====================================================
 

all.do

@@ -0,0 +1,11 @@
+exec >&2
+UI=
+[ "$(uname)" = "Darwin" ] && UI=ui-macos/all
+redo-ifchange sshuttle.8 $UI
+
+echo
+echo "What now?"
+[ -z "$UI" ] || echo "- Try the MacOS GUI: open ui-macos/Sshuttle*.app"
+echo "- Run sshuttle: ./sshuttle --dns -r HOSTNAME 0/0"
+echo "- Read the README: less README.md"
+echo "- Read the man page: less sshuttle.md"

clean.do

@@ -0,0 +1,2 @@
+redo ui-macos/clean
+rm -f *~ */*~ .*~ */.*~ *.8 *.tmp */*.tmp *.pyc */*.pyc

client.py

@@ -102,7 +102,7 @@ class FirewallClient:
         self.subnets_include = subnets_include
         self.subnets_exclude = subnets_exclude
         self.dnsport = dnsport
-        argvbase = ([sys.argv[0]] +
+        argvbase = ([sys.argv[1], sys.argv[0], sys.argv[1]] +
                     ['-v'] * (helpers.verbose or 0) +
                     ['--firewall', str(port), str(dnsport)])
         if ssyslog._p:

default.8.do

@@ -0,0 +1,7 @@
+exec >&2
+if pandoc </dev/null 2>/dev/null; then
+	pandoc -s -r markdown -w man -o $3 $1.md
+else
+	echo "Warning: pandoc not installed; can't generate manpages."
+	redo-always
+fi

do

@@ -0,0 +1,150 @@
+#!/bin/sh
+#
+# A minimal alternative to djb redo that doesn't support incremental builds.
+# For the full version, visit http://github.com/apenwarr/redo
+#
+# The author disclaims copyright to this source file and hereby places it in
+# the public domain. (2010 12 14)
+#
+
+# By default, no output coloring.
+GREEN=""
+BOLD=""
+PLAIN=""
+
+if [ -n "$TERM" -a "$TERM" != "dumb" ] && tty <&2 >/dev/null 2>&1; then
+	GREEN="$(printf '\033[32m')"
+	BOLD="$(printf '\033[1m')"
+	PLAIN="$(printf '\033[m')"
+fi
+
+_dirsplit()
+{
+	base=${1##*/}
+	dir=${1%$base}
+}
+
+_dirsplit "$0"
+export REDO=$(cd "${dir:-.}" && echo "$PWD/$base")
+
+DO_TOP=
+if [ -z "$DO_BUILT" ]; then
+	DO_TOP=1
+	[ -n "$*" ] || set all  # only toplevel redo has a default target
+	export DO_BUILT=$PWD/.do_built
+	: >>"$DO_BUILT"
+	echo "Removing previously built files..." >&2
+	sort -u "$DO_BUILT" | tee "$DO_BUILT.new" |
+	while read f; do printf "%s\0%s.did\0" "$f" "$f"; done |
+	xargs -0 rm -f 2>/dev/null
+	mv "$DO_BUILT.new" "$DO_BUILT"
+	DO_PATH=$DO_BUILT.dir
+	export PATH=$DO_PATH:$PATH
+	rm -rf "$DO_PATH"
+	mkdir "$DO_PATH"
+	for d in redo redo-ifchange; do
+		ln -s "$REDO" "$DO_PATH/$d";
+	done
+	[ -e /bin/true ] && TRUE=/bin/true || TRUE=/usr/bin/true
+	for d in redo-ifcreate redo-stamp redo-always; do 
+		ln -s $TRUE "$DO_PATH/$d";
+	done
+fi
+
+
+_find_dofile_pwd()
+{
+	DOFILE=default.$1.do
+	while :; do
+		DOFILE=default.${DOFILE#default.*.}
+		[ -e "$DOFILE" -o "$DOFILE" = default.do ] && break
+	done
+	EXT=${DOFILE#default}
+	EXT=${EXT%.do}
+	BASE=${1%$EXT}
+}
+
+
+_find_dofile()
+{
+	PREFIX=
+	while :; do
+		_find_dofile_pwd "$1"
+		[ -e "$DOFILE" ] && break
+		[ "$PWD" = "/" ] && break
+		TARGET=${PWD##*/}/$TARGET
+		PREFIX=${PWD##*/}/$PREFIX
+		cd ..
+	done
+	BASE=$PREFIX$BASE
+}
+
+
+_run_dofile()
+{
+	export DO_DEPTH="$DO_DEPTH  "
+	export REDO_TARGET=$PWD/$TARGET
+	set -e
+	read line1 <"$PWD/$DOFILE"
+	cmd=${line1#"#!/"}
+	if [ "$cmd" != "$line1" ]; then
+		/$cmd "$PWD/$DOFILE" "$@" >"$TARGET.tmp2"
+	else
+		. "$PWD/$DOFILE" >"$TARGET.tmp2"
+	fi
+}
+
+
+_do()
+{
+	DIR=$1
+	TARGET=$2
+	if [ ! -e "$TARGET" ] || [ -e "$TARGET/." -a ! -e "$TARGET.did" ]; then
+		printf '%sdo  %s%s%s%s\n' \
+			"$GREEN" "$DO_DEPTH" "$BOLD" "$DIR$TARGET" "$PLAIN" >&2
+		echo "$PWD/$TARGET" >>"$DO_BUILT"
+		DOFILE=$TARGET.do
+		BASE=$TARGET
+		EXT=
+		[ -e "$TARGET.do" ] || _find_dofile "$TARGET"
+		if [ ! -e "$DOFILE" ]; then
+			echo "do: $TARGET: no .do file" >&2
+			return 1
+		fi
+		[ ! -e "$DO_BUILD" ] || : >>"$TARGET.did"
+		( _run_dofile "$BASE" "$EXT" "$TARGET.tmp" )
+		RV=$?
+		if [ $RV != 0 ]; then
+			printf "do: %s%s\n" "$DO_DEPTH" \
+				"$DIR$TARGET: got exit code $RV" >&2
+			rm -f "$TARGET.tmp" "$TARGET.tmp2"
+			return $RV
+		fi
+		mv "$TARGET.tmp" "$TARGET" 2>/dev/null ||
+		! test -s "$TARGET.tmp2" ||
+		mv "$TARGET.tmp2" "$TARGET" 2>/dev/null
+		rm -f "$TARGET.tmp2"
+	else
+		echo "do  $DO_DEPTH$TARGET exists." >&2
+	fi
+}
+
+
+redo()
+{
+	for i in "$@"; do
+		_dirsplit "$i"
+		( cd "$dir" && _do "$dir" "$base" ) || return 1
+	done
+}
+
+
+set -e
+redo "$@"
+
+if [ -n "$DO_TOP" ]; then
+	echo "Removing stamp files..." >&2
+	[ ! -e "$DO_BUILT" ] ||
+	while read f; do printf "%s.did\0" "$f"; done <"$DO_BUILT" |
+	xargs -0 rm -f 2>/dev/null
+fi

firewall.py

@@ -7,6 +7,13 @@ from helpers import *
 IPPROTO_DIVERT = 254
 
 
+def nonfatal(func, *args):
+    try:
+        func(*args)
+    except Fatal, e:
+        log('error: %s\n' % e)
+
+
 def ipt_chain_exists(name):
     argv = ['iptables', '-t', 'nat', '-nL']
     p = ssubprocess.Popen(argv, stdout = ssubprocess.PIPE)
@@ -57,9 +64,9 @@ def do_iptables(port, dnsport, subnets):
 
     # basic cleanup/setup of chains
     if ipt_chain_exists(chain):
-        ipt('-D', 'OUTPUT', '-j', chain)
-        ipt('-D', 'PREROUTING', '-j', chain)
-        ipt('-F', chain)
+        nonfatal(ipt, '-D', 'OUTPUT', '-j', chain)
+        nonfatal(ipt, '-D', 'PREROUTING', '-j', chain)
+        nonfatal(ipt, '-F', chain)
         ipt('-X', chain)
 
     if subnets or dnsport:
@@ -143,7 +150,7 @@ def sysctl_set(name, val, permanent=False):
         _fill_oldctls(PREFIX)
     if not (name in _oldctls):
         debug1('>> No such sysctl: %r\n' % name)
-        return
+        return False
     oldval = _oldctls[name]
     if val != oldval:
         rv = _sysctl_set(name, val)
@@ -156,6 +163,7 @@ def sysctl_set(name, val, permanent=False):
             f.close()
         else:
             _changedctls.append(name)
+        return True
 
 
 def _udp_unpack(p):
@@ -214,7 +222,18 @@ def do_ipfw(port, dnsport, subnets):
 
     if subnets or dnsport:
         sysctl_set('net.inet.ip.fw.enable', 1)
-        sysctl_set('net.inet.ip.scopedroute', 0, permanent=True)
+        changed = sysctl_set('net.inet.ip.scopedroute', 0, permanent=True)
+        if changed:
+            log("\n"
+                "        WARNING: ONE-TIME NETWORK DISRUPTION:\n"
+                "        =====================================\n"
+                "sshuttle has changed a MacOS kernel setting to work around\n"
+                "a bug in MacOS 10.6.  This will cause your network to drop\n"
+                "within 5-10 minutes unless you restart your network\n"
+                "interface (change wireless networks or unplug/plug the\n"
+                "ethernet port) NOW, then restart sshuttle.  The fix is\n"
+                "permanent; you only have to do this once.\n\n")
+            sys.exit(1)
 
         ipfw('add', sport, 'check-state', 'ip',
              'from', 'any', 'to', 'any')

hostwatch.py

@@ -13,7 +13,11 @@ _nmb_ok = True
 _smb_ok = True
 hostnames = {}
 queue = {}
-null = open('/dev/null', 'rb+')
+try:
+    null = open('/dev/null', 'wb')
+except IOError, e:
+    log('warning: %s\n' % e)
+    null = os.popen("sh -c 'while read x; do :; done'", 'wb', 4096)
 
 
 def _is_ip(s):

main.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 import sys, os, re
 import helpers, options, client, server, firewall, hostwatch
 import compat.ssubprocess as ssubprocess
@@ -55,7 +54,7 @@ l,listen=  transproxy to this ip address and port number [127.0.0.1:0]
 H,auto-hosts scan for remote hostnames and update local /etc/hosts
 N,auto-nets  automatically determine subnets to route
 dns        capture local DNS requests and forward to the remote DNS server
-python=    path to python interpreter on the remote server [python]
+python=    path to python interpreter on the remote server
 r,remote=  ssh hostname (and optional username) of remote sshuttle server
 x,exclude= exclude this subnet (can be used more than once)
 v,verbose  increase debug message verbosity
@@ -71,7 +70,7 @@ firewall   (internal use only)
 hostwatch  (internal use only)
 """
 o = options.Options(optspec)
-(opt, flags, extra) = o.parse(sys.argv[1:])
+(opt, flags, extra) = o.parse(sys.argv[2:])
 
 if opt.daemon:
     opt.syslog = 1

server.py

@@ -119,7 +119,14 @@ class DnsProxy(Handler):
         self.sock.send(request)
 
     def callback(self):
-        data = self.sock.recv(4096)
+        try:
+            data = self.sock.recv(4096)
+        except socket.error, e:
+            if e.args[0] == errno.ECONNREFUSED:
+                debug2('DNS response: ignoring ECONNREFUSED.\n')
+                return  # might have been spurious; wait for a real answer
+            else:
+                raise
         debug2('DNS response: %d bytes\n' % len(data))
         self.mux.send(self.chan, ssnet.CMD_DNS_RESPONSE, data)
         self.ok = False

ssh.py

@@ -73,16 +73,23 @@ def connect(ssh_cmd, rhostport, python, stderr, options):
 
         
     if not rhost:
-        argv = [python, '-c', pyscript]
+        # ignore the --python argument when running locally; we already know
+        # which python version works.
+        argv = [sys.argv[1], '-c', pyscript]
     else:
         if ssh_cmd:
             sshl = ssh_cmd.split(' ')
         else:
             sshl = ['ssh']
+        if python:
+            pycmd = "'%s' -c '%s'" % (python, pyscript)
+        else:
+            pycmd = ("P=python2; $P -V 2>/dev/null || P=python; "
+                     "\"$P\" -c '%s'") % pyscript
         argv = (sshl + 
                 portl + 
                 ipv6flag + 
-                [rhost, '--', "'%s' -c '%s'" % (python, pyscript)])
+                [rhost, '--', pycmd])
     (s1,s2) = socket.socketpair()
     def setup():
         # runs in the child process

sshuttle

@@ -1 +0,0 @@
-main.py

sshuttle

@@ -0,0 +1,7 @@
+#!/bin/sh
+DIR=$(dirname "$0")
+if python2 -V 2>/dev/null; then
+	exec python2 "$DIR/main.py" python2 "$@"
+else
+	exec python "$DIR/main.py" python "$@"
+fi

sshuttle.md

@@ -253,6 +253,17 @@ between the two separate streams, so a tcp-based tunnel is
 fine.
 
 
+# BUGS
+
+On MacOS 10.6 (at least up to 10.6.6), your network will
+stop responding about 10 minutes after the first time you
+start sshuttle, because of a MacOS kernel bug relating to
+arp and the net.inet.ip.scopedroute sysctl.  To fix it,
+just switch your wireless off and on. Sshuttle makes the
+kernel setting it changes permanent, so this won't happen
+again, even after a reboot.
+
+
 # SEE ALSO
 
 `ssh`(1), `python`(1)

stresstest.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import sys, os, socket, select, struct, time
 
 listener = socket.socket()

ui-macos/clean.do

@@ -1,4 +1,4 @@
 exec >&2
-find -name '*~' | xargs rm -f
+find . -name '*~' | xargs rm -f
 rm -rf *.app *.zip *.tar.gz
 rm -f bits/runpython *.nib sources.list