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Default route override and route management in general now works in Linux.

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This commit is contained in:
Adam Ierymenko 2016-06-21 12:32:58 -07:00
parent 51ced0cf41
commit 82473c85e0
2 changed files with 79 additions and 40 deletions
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55
osdep/ManagedRoute.cpp
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@ -55,6 +55,7 @@
#define ZT_BSD_ROUTE_CMD "/sbin/route"
#define ZT_LINUX_IP_COMMAND "/sbin/ip"
#define ZT_LINUX_IP_COMMAND_2 "/usr/sbin/ip"
namespace ZeroTier {
@ -258,6 +259,26 @@ static void _routeCmd(const char *op,const InetAddress &target,const InetAddress
#ifdef __LINUX__ // ----------------------------------------------------------
#define ZT_ROUTING_SUPPORT_FOUND 1
static void _routeCmd(const char *op,const InetAddress &target,const InetAddress &via,const char *localInterface)
{
long p = (long)fork();
if (p > 0) {
int exitcode = -1;
::waitpid(p,&exitcode,0);
} else if (p == 0) {
::close(STDOUT_FILENO);
::close(STDERR_FILENO);
if (via) {
::execl(ZT_LINUX_IP_COMMAND,ZT_LINUX_IP_COMMAND,(target.ss_family == AF_INET6) ? "-6" : "-4","route",op,target.toString().c_str(),"via",via.toIpString().c_str(),(const char *)0);
::execl(ZT_LINUX_IP_COMMAND_2,ZT_LINUX_IP_COMMAND_2,(target.ss_family == AF_INET6) ? "-6" : "-4","route",op,target.toString().c_str(),"via",via.toIpString().c_str(),(const char *)0);
} else if ((localInterface)&&(localInterface[0])) {
::execl(ZT_LINUX_IP_COMMAND,ZT_LINUX_IP_COMMAND,(target.ss_family == AF_INET6) ? "-6" : "-4","route",op,target.toString().c_str(),"dev",localInterface,(const char *)0);
::execl(ZT_LINUX_IP_COMMAND_2,ZT_LINUX_IP_COMMAND_2,(target.ss_family == AF_INET6) ? "-6" : "-4","route",op,target.toString().c_str(),"dev",localInterface,(const char *)0);
}
::_exit(-1);
}
}
#endif // __LINUX__ ----------------------------------------------------------
#ifdef __WINDOWS__ // --------------------------------------------------------
@ -271,6 +292,17 @@ static void _routeCmd(const char *op,const InetAddress &target,const InetAddress
} // anonymous namespace
/* Linux NOTE: for default route override, some Linux distributions will
* require a change to the rp_filter parameter.
*
* sudo sysctl net.ipv4.conf.all.rp_filter=2
*
* Add to /etc/sysctl.conf or /etc/sysctl.d/... to make permanent.
*
* This is true of CentOS/RHEL 6+ and possibly others. This is because
* Linux default route override implies asymmetric routes, which then
* trigger Linux's "martian packet" filter. */
bool ManagedRoute::sync()
{
if ((_target.isDefaultRoute())||((_target.ss_family == AF_INET)&&(_target.netmaskBits() < 32))) {
@ -357,6 +389,12 @@ bool ManagedRoute::sync()
#ifdef __LINUX__ // ----------------------------------------------------------
if (!_applied) {
_routeCmd("replace",leftt,_via,(_via) ? _device : (const char *)0);
_routeCmd("replace",rightt,_via,(_via) ? _device : (const char *)0);
_applied = true;
}
#endif // __LINUX__ ----------------------------------------------------------
#ifdef __WINDOWS__ // --------------------------------------------------------
@ -364,8 +402,6 @@ bool ManagedRoute::sync()
#endif // __WINDOWS__ --------------------------------------------------------
} else {
/* For non-default routes, IPv4 /32, and IPv6 non-default routes, we just
* add the route itself. */
#ifdef __BSD__ // ------------------------------------------------------------
@ -398,14 +434,7 @@ bool ManagedRoute::sync()
void ManagedRoute::remove()
{
if (_applied) {
if (_target.isDefaultRoute()) {
/* In ZeroTier we use a forked-route trick to override the default
* with a more specific one while leaving the original system route
* intact. We also create a shadow more specific route to the
* original gateway that is device-bound so that ZeroTier's device
* bound ports go via the physical Internet link. This has to be
* done *slightly* differently on different platforms. */
if ((_target.isDefaultRoute())||((_target.ss_family == AF_INET)&&(_target.netmaskBits() < 32))) {
InetAddress leftt,rightt;
_forkTarget(_target,leftt,rightt);
@ -415,7 +444,6 @@ void ManagedRoute::remove()
_routeCmd("delete",leftt,_systemVia,_systemDevice,(const char *)0);
_routeCmd("delete",rightt,_systemVia,_systemDevice,(const char *)0);
}
if (_via) {
_routeCmd("delete",leftt,_via,(const char *)0,(const char *)0);
_routeCmd("delete",rightt,_via,(const char *)0,(const char *)0);
@ -428,6 +456,9 @@ void ManagedRoute::remove()
#ifdef __LINUX__ // ----------------------------------------------------------
_routeCmd("del",leftt,_via,(_via) ? _device : (const char *)0);
_routeCmd("del",rightt,_via,(_via) ? _device : (const char *)0);
#endif // __LINUX__ ----------------------------------------------------------
#ifdef __WINDOWS__ // --------------------------------------------------------
@ -448,6 +479,8 @@ void ManagedRoute::remove()
#ifdef __LINUX__ // ----------------------------------------------------------
_routeCmd("del",_target,_via,(_via) ? _device : (const char *)0);
#endif // __LINUX__ ----------------------------------------------------------
#ifdef __WINDOWS__ // --------------------------------------------------------