[372] in linux-net channel archive
RTF_BLOCK patch
daemon@ATHENA.MIT.EDU (ukd1@rz.uni-karlsruhe.de)
Wed May 24 20:47:35 1995
From: ukd1@rz.uni-karlsruhe.de
To: linux-kernel@vger.rutgers.edu, linux-net@vger.rutgers.edu
Followup-To: comp.os.linux.development.system
Date: 24 May 1995 21:52:11 GMT
I have written some small Kernelpatches to enable the metric field in the
Kernel-Routing Table, an additional Flag for automatically generated routes
by routing daemons a flag for setting up 'blocking' routes (dead routes) and
some more support for usermode routing daemons. See the README for
clearification.
The Patches, the Readme and the additional Programs can be found on
http://www.inka.de/sites/lina/linux/route/ or
ftp://ftp.inka.de/sites/lina/linux/route/
If you are a Developer give me some Feedback (especially about the
implementation).
Included after the Readme is _only_ route1.patch, see the above location for
the suplemental stuff.
BEGIN README ----------------------------------------------------------------
route patch
-----------
INSTALL
-------
route1.patch - apply this to 1.2.8 Kernel with
cd /usr/src
patch -p0 < route1.patch
cd linux ; make zLilo # recompile Kernel
to add two new Flags for SIOCADDRT ioctl call (add route). And to add an
additional IOCTL SIOCSLEEPRT. The Metric field in the Kernel routing
table will get accesable, too.
route2.patch - apply this to nettools-1.2.0.tar.gz with
cd /usr/src/net
patch -p0 < route2.patch
make install # recompile binary
to add support for the new routing Flags.
DESCRIPTION (the main purpose of this patch is metric and RTF_BLOCK)
-----------
RTF_AUTO - is a Flag, which will be set from a user-mode program to indicate
that the new route is set from a routing daemon and not 'manually' on
bootup or dialin. The Kernel saves the flag but does not query it. This
is only for the usermode to mark dynamic routes (like RTF_DYNAMIC for
ICMP redirects). Non RTF_AUTO routes should not be changed from an
routing daemon. (It is possible to set the auto flag with the modified
route command (route2.patch), but this is only for batch or debugging
usage.
metric - The Metric Value provided by SIOCADDRT will now be stored in the
kernel routing table. This value isnt used by the Kernel, its for
usermode only.
SIOCSLEEPRT - IOCTL to allow a usermode program to sleep until there is a
modification at the routing table. (by SIOC*RT or ICMP redirets)
RTF_BLOCK - This allows to install a (net)'route' which will make the
lookup for a route fail. This is used to notify the sender that the
destination is unreachable. This is at the curent implementation not
possible, if there is a default Gateway (which is very common on Systems
with access to the Internet).
RTF_BLOCK is not primary for Firewalling (use IP_FIREWALL, ipfwadm
instead) but to allow Linux to generate probably error Messages instead
of Timeouts for unreachable (site-local) hosts.
Example
-----------------------------------------
Kernel routing table
Destination Gateway Genmask Flags MSS Window Use Iface
localhost. * 255.255.255.255 UH 1936 0 7 lo
host1.doma.in * 255.255.255.255 UH 1436 0 10 eth0
host2.doma.in * 255.255.255.255 UH 1436 0 12 eth0
host3.doma.in host2.doma.in 255.255.255.255 UHGA 1436 0 1 eth0
doma-in-net * 255.255.255.0 UB 1436 0 1 eth0
default host1.doma.in * UG 1436 0 100 eth0
-----------------------------------------
This Table is an example. localhost, host1 and host2 are set manually.
host3 is set by some user-mode routing daemon and doma-in-net is a
blocking route installed with:
route add -net doma-in-net dev eth0 block
In this example this particular hosts only routes packets to host1 host2
and host3 of the domai-in-net. The World is still reachable. If the
blocking route is missing all acces to unknown hosts of the local net
will be routed to the default gateway.
An other Example:
-----------------------------------------
Kernel routing table
Destination Gateway Genmask Flags MSS Window Use Iface
localhost. * 255.255.255.255 UH 1936 0 7 lo
host1.doma.in * 255.255.255.255 UHB 1436 0 10 eth0
doma-in-net * 255.255.255.0 U 1436 0 1 eth0
-----------------------------------------
In this case a packet to host1 will be rejected with a 'now route to
host' but all other hosts from the Class-C Network attached to the eth0
can be accessed if present. If they are not present it ony will generate
a timeout.
bernd.eckenfels@inka.de
END README ----------------------------------------------------------------
BEGIN route1.patch -----------------------------------------------------------
Patch to add RTF_AUTO, RTF_BLOCK, metric and SIOCSLEEPRT Support to Kernel.
This should cleanly patch at least against 1.2.8.
diff -u --recursive --new-file linux/include/linux/route.h.org linux/include/linux/route.h
--- route.c.org Sun May 7 19:47:06 1995
+++ route.c Sun May 21 07:15:04 1995
@@ -24,6 +24,7 @@
* Alan Cox : MSS actually. Also added the window
* clamper.
* Sam Lantinga : Fixed route matching in rt_del()
+ * Bernd Eckenfels : Metric and RTF_BLOCK support
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -65,6 +66,15 @@
static struct rtable *rt_loopback = NULL;
/*
+ * Waitqueue and Version for table changes
+ */
+
+static struct wait_queue * rt_change_wait = NULL;
+static unsigned rt_version=0;
+
+#define rt_change_wakeup() rt_version++; wake_up_interruptible(&rt_change_wait);
+
+/*
* Remove a routing table entry.
*/
@@ -72,8 +82,10 @@
{
struct rtable *r, **rp;
unsigned long flags;
+ short changed;
rp = &rt_base;
+ changed = 0;
/*
* This must be done with interrupts off because we could take
@@ -92,6 +104,7 @@
continue;
}
*rp = r->rt_next;
+ changed = 1;
/*
* If we delete the loopback route update its pointer.
@@ -102,6 +115,8 @@
kfree_s(r, sizeof(struct rtable));
}
restore_flags(flags);
+ if (changed)
+ rt_change_wakeup();
}
@@ -115,8 +130,10 @@
struct rtable *r;
struct rtable **rp;
unsigned long flags;
+ short changed;
rp = &rt_base;
+ changed = 0;
save_flags(flags);
cli();
while ((r = *rp) != NULL) {
@@ -125,11 +142,14 @@
continue;
}
*rp = r->rt_next;
+ changed = 1;
if (rt_loopback == r)
rt_loopback = NULL;
kfree_s(r, sizeof(struct rtable));
}
restore_flags(flags);
+ if (changed)
+ rt_change_wakeup();
}
/*
@@ -201,7 +221,8 @@
*/
void ip_rt_add(short flags, unsigned long dst, unsigned long mask,
- unsigned long gw, struct device *dev, unsigned short mtu, unsigned long window)
+ unsigned long gw, struct device *dev, unsigned short mtu,
+ unsigned long window, short metric)
{
struct rtable *r, *rt;
struct rtable **rp;
@@ -273,6 +294,7 @@
rt->rt_dev = dev;
rt->rt_gateway = gw;
rt->rt_mask = mask;
+ rt->rt_metric = metric;
rt->rt_mss = dev->mtu - HEADER_SIZE;
rt->rt_window = 0; /* Default is no clamping */
@@ -338,6 +360,7 @@
*/
restore_flags(cpuflags);
+ rt_change_wakeup();
return;
}
@@ -460,7 +483,8 @@
* Add the route
*/
- ip_rt_add(flags, daddr, mask, gw, dev, r->rt_mss, r->rt_window);
+ ip_rt_add(flags, daddr, mask, gw, dev,
+ r->rt_mss, r->rt_window, r->rt_metric);
return 0;
}
@@ -511,7 +535,7 @@
for (r = rt_base; r != NULL; r = r->rt_next)
{
- size = sprintf(buffer+len, "%s\t%08lX\t%08lX\t%02X\t%d\t%lu\t%d\t%08lX\t%d\t%lu\n",
+ size = sprintf(buffer+len, "%s\t%08lX\t%08lX\t%04X\t%d\t%lu\t%d\t%08lX\t%d\t%lu\n",
r->rt_dev->name, r->rt_dst, r->rt_gateway,
r->rt_flags, r->rt_refcnt, r->rt_use, r->rt_metric,
r->rt_mask, (int)r->rt_mss, r->rt_window);
@@ -564,6 +588,8 @@
break;
}
+ if (rt->rt_flags & RTF_BLOCK)
+ goto no_route;
if(src_addr!=NULL)
*src_addr= rt->rt_dev->pa_addr;
@@ -645,6 +671,7 @@
{
int err;
struct rtentry rt;
+ unsigned tmp_rt_version;
switch(cmd)
{
@@ -666,7 +693,16 @@
return err;
memcpy_fromfs(&rt, arg, sizeof(struct rtentry));
return (cmd == SIOCDELRT) ? rt_kill(&rt) : rt_new(&rt);
- }
+ case SIOCSLEEPRT: /* Sleep for routing table modification */
+ tmp_rt_version = rt_version;
+ while(tmp_rt_version == rt_version) {
+
+ interruptible_sleep_on(&rt_change_wait);
+
+ if (current->signal & ~current->blocked)
+ return(-EINTR);
+ }
+ }
return -EINVAL;
}
END route1.patch -----------------------------------------------------------
-- __
(OO) -- Bernd_Eckenfels@Wittumstrasse13.76646Bruchsal.de --
( .. ) +4972573817 ecki@lina.{inka.de,ka.sub.org} ukd1@rz.uni.karlsruhe.de
o--o *QUAK* Jetzt auch mit Plueschtier in der .Sig!
(O____O) <A href=http://rzstud1.rz.uni-karlsruhe.de/~ukd1/>Eckes@IRC</A>
