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net: RFC3069, private VLAN proxy arp support

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This is to be used together with switch technologies, like RFC3069,
that where the individual ports are not allowed to communicate with
each other, but they are allowed to talk to the upstream router.  As
described in RFC 3069, it is possible to allow these hosts to
communicate through the upstream router by proxy_arp'ing.

This patch basically allow proxy arp replies back to the same
interface (from which the ARP request/solicitation was received).

Tunable per device via proc "proxy_arp_pvlan":
  /proc/sys/net/ipv4/conf/*/proxy_arp_pvlan

This switch technology is known by different vendor names:
 - In RFC 3069 it is called VLAN Aggregation.
 - Cisco and Allied Telesyn call it Private VLAN.
 - Hewlett-Packard call it Source-Port filtering or port-isolation.
 - Ericsson call it MAC-Forced Forwarding (RFC Draft).

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jesper Dangaard Brouer 2010-01-05 05:50:47 +00:00 committed by David S. Miller
parent ca8d9ea30b
commit 65324144b5
6 changed files with 76 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
Documentation/networking/ip-sysctl.txt
View File

@ -692,6 +692,25 @@ proxy_arp - BOOLEAN
conf/{all,interface}/proxy_arp is set to TRUE,
it will be disabled otherwise
proxy_arp_pvlan - BOOLEAN
Private VLAN proxy arp.
Basically allow proxy arp replies back to the same interface
(from which the ARP request/solicitation was received).
This is done to support (ethernet) switch features, like RFC
3069, where the individual ports are NOT allowed to
communicate with each other, but they are allowed to talk to
the upstream router. As described in RFC 3069, it is possible
to allow these hosts to communicate through the upstream
router by proxy_arp'ing. Don't need to be used together with
proxy_arp.
This technology is known by different names:
In RFC 3069 it is called VLAN Aggregation.
Cisco and Allied Telesyn call it Private VLAN.
Hewlett-Packard call it Source-Port filtering or port-isolation.
Ericsson call it MAC-Forced Forwarding (RFC Draft).
shared_media - BOOLEAN
Send(router) or accept(host) RFC1620 shared media redirects.
Overrides ip_secure_redirects.

1
include/linux/inetdevice.h
View File

@ -88,6 +88,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
#define IN_DEV_LOG_MARTIANS(in_dev) IN_DEV_ORCONF((in_dev), LOG_MARTIANS)
#define IN_DEV_PROXY_ARP(in_dev) IN_DEV_ORCONF((in_dev), PROXY_ARP)
#define IN_DEV_PROXY_ARP_PVLAN(in_dev) IN_DEV_CONF_GET(in_dev, PROXY_ARP_PVLAN)
#define IN_DEV_SHARED_MEDIA(in_dev) IN_DEV_ORCONF((in_dev), SHARED_MEDIA)
#define IN_DEV_TX_REDIRECTS(in_dev) IN_DEV_ORCONF((in_dev), SEND_REDIRECTS)
#define IN_DEV_SEC_REDIRECTS(in_dev) IN_DEV_ORCONF((in_dev), \

1
include/linux/sysctl.h
View File

@ -482,6 +482,7 @@ enum
NET_IPV4_CONF_ARP_ACCEPT=21,
NET_IPV4_CONF_ARP_NOTIFY=22,
NET_IPV4_CONF_ACCEPT_LOCAL=23,
NET_IPV4_CONF_PROXY_ARP_PVLAN=24,
__NET_IPV4_CONF_MAX
};

52
net/ipv4/arp.c
View File

@ -70,6 +70,7 @@
* bonding can change the skb before
* sending (e.g. insert 8021q tag).
* Harald Welte : convert to make use of jenkins hash
* Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
*/
#include <linux/module.h>
@ -524,12 +525,15 @@ int arp_bind_neighbour(struct dst_entry *dst)
/*
* Check if we can use proxy ARP for this path
*/
static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
static inline int arp_fwd_proxy(struct in_device *in_dev,
struct net_device *dev, struct rtable *rt)
{
struct in_device *out_dev;
int imi, omi = -1;
if (rt->u.dst.dev == dev)
return 0;
if (!IN_DEV_PROXY_ARP(in_dev))
return 0;
@ -547,6 +551,43 @@ static inline int arp_fwd_proxy(struct in_device *in_dev, struct rtable *rt)
return (omi != imi && omi != -1);
}
/*
* Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
*
* RFC3069 supports proxy arp replies back to the same interface. This
* is done to support (ethernet) switch features, like RFC 3069, where
* the individual ports are not allowed to communicate with each
* other, BUT they are allowed to talk to the upstream router. As
* described in RFC 3069, it is possible to allow these hosts to
* communicate through the upstream router, by proxy_arp'ing.
*
* RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
*
* This technology is known by different names:
* In RFC 3069 it is called VLAN Aggregation.
* Cisco and Allied Telesyn call it Private VLAN.
* Hewlett-Packard call it Source-Port filtering or port-isolation.
* Ericsson call it MAC-Forced Forwarding (RFC Draft).
*
*/
static inline int arp_fwd_pvlan(struct in_device *in_dev,
struct net_device *dev, struct rtable *rt,
__be32 sip, __be32 tip)
{
/* Private VLAN is only concerned about the same ethernet segment */
if (rt->u.dst.dev != dev)
return 0;
/* Don't reply on self probes (often done by windowz boxes)*/
if (sip == tip)
return 0;
if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
return 1;
else
return 0;
}
/*
* Interface to link layer: send routine and receive handler.
*/
@ -833,8 +874,11 @@ static int arp_process(struct sk_buff *skb)
}
goto out;
} else if (IN_DEV_FORWARD(in_dev)) {
if (addr_type == RTN_UNICAST && rt->u.dst.dev != dev &&
(arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, net, &tip, dev, 0))) {
if (addr_type == RTN_UNICAST &&
(arp_fwd_proxy(in_dev, dev, rt) ||
arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))
{
n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
if (n)
neigh_release(n);

1
net/ipv4/devinet.c
View File

@ -1407,6 +1407,7 @@ static struct devinet_sysctl_table {
DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"),
DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),

7
net/ipv4/route.c
View File

@ -1988,8 +1988,13 @@ static int __mkroute_input(struct sk_buff *skb,
if (skb->protocol != htons(ETH_P_IP)) {
/* Not IP (i.e. ARP). Do not create route, if it is
* invalid for proxy arp. DNAT routes are always valid.
*
* Proxy arp feature have been extended to allow, ARP
* replies back to the same interface, to support
* Private VLAN switch technologies. See arp.c.
*/
if (out_dev == in_dev) {
if (out_dev == in_dev &&
IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
err = -EINVAL;
goto cleanup;
}