diff -urp v2.6.22/linux/Documentation/filesystems/proc.txt linux/Documentation/filesystems/proc.txt
--- v2.6.22/linux/Documentation/filesystems/proc.txt 2007-07-10 09:18:37.000000000 +0300
+++ linux/Documentation/filesystems/proc.txt 2007-07-12 09:28:35.000000000 +0300
@@ -1700,6 +1700,15 @@ log_martians
Log packets with source addresses with no known route to kernel log.
+loop
+----
+
+By default (loop=0) the traffic between local IP addresses
+is routed via interface "lo". Setting this flag for two
+interfaces allows traffic between their IP addresses to
+be looped externally. This is useful for setups where the
+interfaces are attached to same broadcast medium.
+
mc_forwarding
-------------
diff -urp v2.6.22/linux/Documentation/networking/ip-sysctl.txt linux/Documentation/networking/ip-sysctl.txt
--- v2.6.22/linux/Documentation/networking/ip-sysctl.txt 2007-07-10 09:18:37.000000000 +0300
+++ linux/Documentation/networking/ip-sysctl.txt 2007-07-12 09:28:35.000000000 +0300
@@ -587,6 +587,13 @@ accept_redirects - BOOLEAN
forwarding - BOOLEAN
Enable IP forwarding on this interface.
+loop - BOOLEAN
+ By default (loop=0) the traffic between local IP addresses
+ is routed via interface "lo". Setting this flag for two
+ interfaces allows traffic between their IP addresses to
+ be looped externally. This is useful for setups where the
+ interfaces are attached to same broadcast medium.
+
mc_forwarding - BOOLEAN
Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
and a multicast routing daemon is required.
diff -urp v2.6.22/linux/include/linux/inetdevice.h linux/include/linux/inetdevice.h
--- v2.6.22/linux/include/linux/inetdevice.h 2007-07-10 09:18:42.000000000 +0300
+++ linux/include/linux/inetdevice.h 2007-07-12 09:31:18.000000000 +0300
@@ -105,6 +105,7 @@ static inline void ipv4_devconf_setall(s
IN_DEV_ORCONF((in_dev), ACCEPT_REDIRECTS)))
#define IN_DEV_ARPFILTER(in_dev) IN_DEV_ORCONF((in_dev), ARPFILTER)
+#define IN_DEV_LOOP(in_dev) IN_DEV_CONF_GET(in_dev, LOOP)
#define IN_DEV_ARP_ANNOUNCE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_ANNOUNCE)
#define IN_DEV_ARP_IGNORE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_IGNORE)
diff -urp v2.6.22/linux/include/linux/sysctl.h linux/include/linux/sysctl.h
--- v2.6.22/linux/include/linux/sysctl.h 2007-07-10 09:18:42.000000000 +0300
+++ linux/include/linux/sysctl.h 2007-07-12 09:28:35.000000000 +0300
@@ -496,6 +496,7 @@ enum
NET_IPV4_CONF_ARP_IGNORE=19,
NET_IPV4_CONF_PROMOTE_SECONDARIES=20,
NET_IPV4_CONF_ARP_ACCEPT=21,
+ NET_IPV4_CONF_LOOP=22,
__NET_IPV4_CONF_MAX
};
diff -urp v2.6.22/linux/net/ipv4/devinet.c linux/net/ipv4/devinet.c
--- v2.6.22/linux/net/ipv4/devinet.c 2007-07-10 09:18:43.000000000 +0300
+++ linux/net/ipv4/devinet.c 2007-07-12 09:32:46.000000000 +0300
@@ -1448,6 +1448,7 @@ static struct devinet_sysctl_table {
DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
+ DEVINET_SYSCTL_RW_ENTRY(LOOP, "loop"),
DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
diff -urp v2.6.22/linux/net/ipv4/fib_frontend.c linux/net/ipv4/fib_frontend.c
--- v2.6.22/linux/net/ipv4/fib_frontend.c 2007-07-10 09:18:43.000000000 +0300
+++ linux/net/ipv4/fib_frontend.c 2007-07-12 09:28:35.000000000 +0300
@@ -189,15 +189,16 @@ int fib_validate_source(__be32 src, __be
.tos = tos } },
.iif = oif };
struct fib_result res;
- int no_addr, rpf;
+ int no_addr, rpf, loop;
int ret;
- no_addr = rpf = 0;
+ no_addr = rpf = loop = 0;
rcu_read_lock();
in_dev = __in_dev_get_rcu(dev);
if (in_dev) {
no_addr = in_dev->ifa_list == NULL;
rpf = IN_DEV_RPFILTER(in_dev);
+ loop = IN_DEV_LOOP(in_dev);
}
rcu_read_unlock();
@@ -206,6 +207,11 @@ int fib_validate_source(__be32 src, __be
if (fib_lookup(&fl, &res))
goto last_resort;
+ if (loop && res.type == RTN_LOCAL) {
+ *spec_dst = FIB_RES_PREFSRC(res);
+ fib_res_put(&res);
+ return 0;
+ }
if (res.type != RTN_UNICAST)
goto e_inval_res;
*spec_dst = FIB_RES_PREFSRC(res);
diff -urp v2.6.22/linux/net/ipv4/route.c linux/net/ipv4/route.c
--- v2.6.22/linux/net/ipv4/route.c 2007-07-10 09:18:43.000000000 +0300
+++ linux/net/ipv4/route.c 2007-07-12 09:28:35.000000000 +0300
@@ -2444,6 +2444,11 @@ static int ip_route_output_slow(struct r
dev_put(dev_out);
goto out; /* Wrong error code */
}
+ err = -ENETDOWN;
+ if (!(dev_out->flags&IFF_UP)) {
+ dev_put(dev_out);
+ goto out;
+ }
if (LOCAL_MCAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
if (!fl.fl4_src)
@@ -2510,10 +2515,41 @@ static int ip_route_output_slow(struct r
free_res = 1;
if (res.type == RTN_LOCAL) {
- if (!fl.fl4_src)
- fl.fl4_src = fl.fl4_dst;
+ struct in_device *in_dev;
+ __be32 src;
+
if (dev_out)
dev_put(dev_out);
+ dev_out = FIB_RES_DEV(res);
+ in_dev = in_dev_get(dev_out);
+ src = fl.fl4_src? : FIB_RES_PREFSRC(res);
+ if (in_dev && IN_DEV_LOOP(in_dev) && src) {
+ struct net_device *dev_src;
+
+ in_dev_put(in_dev);
+ in_dev = NULL;
+ dev_src = ip_dev_find(src);
+ if (dev_src && dev_src != dev_out &&
+ (in_dev = in_dev_get(dev_src)) &&
+ IN_DEV_LOOP(in_dev)) {
+ in_dev_put(in_dev);
+ dev_out = dev_src;
+ fl.fl4_src = src;
+ fl.oif = dev_out->ifindex;
+ res.type = RTN_UNICAST;
+ if (res.fi) {
+ fib_info_put(res.fi);
+ res.fi = NULL;
+ }
+ goto make_route;
+ }
+ if (dev_src)
+ dev_put(dev_src);
+ }
+ if (in_dev)
+ in_dev_put(in_dev);
+ if (!fl.fl4_src)
+ fl.fl4_src = fl.fl4_dst;
dev_out = &loopback_dev;
dev_hold(dev_out);
fl.oif = dev_out->ifindex;