diff -ur v2.5.73/linux/Documentation/filesystems/proc.txt linux/Documentation/filesystems/proc.txt --- v2.5.73/linux/Documentation/filesystems/proc.txt Sun Jun 15 10:23:55 2003 +++ linux/Documentation/filesystems/proc.txt Tue Jul 1 23:29:02 2003 @@ -1502,6 +1502,15 @@ 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 -ur v2.5.73/linux/Documentation/networking/ip-sysctl.txt linux/Documentation/networking/ip-sysctl.txt --- v2.5.73/linux/Documentation/networking/ip-sysctl.txt Sun Jun 15 10:23:56 2003 +++ linux/Documentation/networking/ip-sysctl.txt Tue Jul 1 23:27:02 2003 @@ -390,6 +390,13 @@ 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 -ur v2.5.73/linux/include/linux/inetdevice.h linux/include/linux/inetdevice.h --- v2.5.73/linux/include/linux/inetdevice.h Sun Apr 20 11:02:16 2003 +++ linux/include/linux/inetdevice.h Mon Jun 30 23:46:20 2003 @@ -21,6 +21,7 @@ int medium_id; int no_xfrm; int no_policy; + int loop; void *sysctl; }; @@ -70,6 +71,7 @@ (ipv4_devconf.accept_redirects || (in_dev)->cnf.accept_redirects))) #define IN_DEV_ARPFILTER(in_dev) (ipv4_devconf.arp_filter || (in_dev)->cnf.arp_filter) +#define IN_DEV_LOOP(in_dev) ((in_dev)->cnf.loop) struct in_ifaddr { diff -ur v2.5.73/linux/include/linux/sysctl.h linux/include/linux/sysctl.h --- v2.5.73/linux/include/linux/sysctl.h Sun Jun 15 10:25:03 2003 +++ linux/include/linux/sysctl.h Mon Jun 30 23:47:14 2003 @@ -359,6 +359,7 @@ NET_IPV4_CONF_MEDIUM_ID=14, NET_IPV4_CONF_NOXFRM=15, NET_IPV4_CONF_NOPOLICY=16, + NET_IPV4_CONF_LOOP=17, }; /* /proc/sys/net/ipv6 */ diff -ur v2.5.73/linux/net/ipv4/devinet.c linux/net/ipv4/devinet.c --- v2.5.73/linux/net/ipv4/devinet.c Sun Jun 15 10:25:07 2003 +++ linux/net/ipv4/devinet.c Mon Jun 30 23:49:26 2003 @@ -1122,7 +1122,7 @@ static struct devinet_sysctl_table { struct ctl_table_header *sysctl_header; - ctl_table devinet_vars[17]; + ctl_table devinet_vars[18]; ctl_table devinet_dev[2]; ctl_table devinet_conf_dir[2]; ctl_table devinet_proto_dir[2]; @@ -1258,6 +1258,14 @@ .mode = 0644, .proc_handler = &ipv4_doint_and_flush, .strategy = &ipv4_doint_and_flush_strategy, + }, + { + .ctl_name = NET_IPV4_CONF_LOOP, + .procname = "loop", + .data = &ipv4_devconf.loop, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, }, }, .devinet_dev = { diff -ur v2.5.73/linux/net/ipv4/fib_frontend.c linux/net/ipv4/fib_frontend.c --- v2.5.73/linux/net/ipv4/fib_frontend.c Wed May 28 00:02:50 2003 +++ linux/net/ipv4/fib_frontend.c Mon Jun 30 23:52:38 2003 @@ -167,15 +167,16 @@ .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; read_lock(&inetdev_lock); in_dev = __in_dev_get(dev); if (in_dev) { no_addr = in_dev->ifa_list == NULL; rpf = IN_DEV_RPFILTER(in_dev); + loop = IN_DEV_LOOP(in_dev); } read_unlock(&inetdev_lock); @@ -184,6 +185,11 @@ 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 -ur v2.5.73/linux/net/ipv4/route.c linux/net/ipv4/route.c --- v2.5.73/linux/net/ipv4/route.c Tue Jun 17 21:39:39 2003 +++ linux/net/ipv4/route.c Tue Jul 1 00:29:05 2003 @@ -1967,6 +1967,11 @@ 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 == 0xFFFFFFFF) { if (!fl.fl4_src) @@ -2036,10 +2041,41 @@ goto e_inval; if (res.type == RTN_LOCAL) { - if (!fl.fl4_src) - fl.fl4_src = fl.fl4_dst; + struct in_device *in_dev; + u32 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;