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From: Stephen Hemminger <stephen@networkplumber.org>
Date: Mon, 29 Apr 2013 18:50:15 -0700
Subject: [PATCH] VyOS: Add linkstate IP device attribute
Backport of earlier Vyatta patch.
(cherry picked from commit 7c5a851086686be14ae937c80d6cee34814dbefc)
Refreshed against Linux 6.18.x:
* include/uapi/linux/ipv6.h gained DEVCONF_FORCE_FORWARDING; insert
DEVCONF_LINK_FILTER after it so the new sentinel keeps a stable value.
* include/linux/ipv6.h grew ra_honor_pio_life / ra_honor_pio_pflag
members before sysctl_header.
* net/ipv6/addrconf.c::ipv6_store_devconf() now uses READ_ONCE() and
publishes DEVCONF_FORCE_FORWARDING; use READ_ONCE() for link_filter
and append after force_forwarding.
* net/ipv6/route.c context shifted; rt6_link_filter() unchanged.
---
Documentation/networking/ip-sysctl.rst | 11 +++++++++++
include/linux/inetdevice.h | 1 +
include/linux/ipv6.h | 1 +
include/uapi/linux/ip.h | 1 +
include/uapi/linux/ipv6.h | 1 +
net/ipv4/devinet.c | 1 +
net/ipv6/addrconf.c | 8 ++++++++
net/ipv6/route.c | 10 ++++++++++
8 files changed, 34 insertions(+)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2042,6 +2042,17 @@ src_valid_mark - BOOLEAN
Default value is 0.
+link_filter - INTEGER
+ 0 - Allow packets to be received for the address on this interface
+ even if interface is disabled or no carrier.
+ 1 - Ignore packets received if interface associated with the incoming
+ address is down.
+ 2 - Ignore packets received if interface associated with the incoming
+ address is down or has no carrier.
+
+ Default value is 0. Note that some distributions enable it
+ in startup scripts.
+
arp_filter - BOOLEAN
- 1 - Allows you to have multiple network interfaces on the same
subnet, and have the ARPs for each interface be answered
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -139,6 +139,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
#define IN_DEV_ARP_NOTIFY(in_dev) IN_DEV_MAXCONF((in_dev), ARP_NOTIFY)
#define IN_DEV_ARP_EVICT_NOCARRIER(in_dev) IN_DEV_ANDCONF((in_dev), \
ARP_EVICT_NOCARRIER)
+#define IN_DEV_LINKFILTER(in_dev) IN_DEV_MAXCONF((in_dev), LINKFILTER)
struct in_ifaddr {
struct hlist_node addr_lst;
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -91,6 +91,7 @@ struct ipv6_devconf {
__u8 ndisc_evict_nocarrier;
__u8 ra_honor_pio_life;
__u8 ra_honor_pio_pflag;
+ __s32 link_filter;
struct ctl_table_header *sysctl_header;
};
diff --git a/include/uapi/linux/ip.h b/include/uapi/linux/ip.h
--- a/include/uapi/linux/ip.h
+++ b/include/uapi/linux/ip.h
@@ -189,6 +189,7 @@ enum
IPV4_DEVCONF_DROP_GRATUITOUS_ARP,
IPV4_DEVCONF_BC_FORWARDING,
IPV4_DEVCONF_ARP_EVICT_NOCARRIER,
+ IPV4_DEVCONF_LINKFILTER,
__IPV4_DEVCONF_MAX
};
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -200,6 +200,7 @@ enum {
DEVCONF_ACCEPT_UNTRACKED_NA,
DEVCONF_ACCEPT_RA_MIN_LFT,
DEVCONF_FORCE_FORWARDING,
+ DEVCONF_LINK_FILTER,
DEVCONF_MAX
};
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -2652,6 +2652,7 @@ static struct devinet_sysctl_table {
"route_localnet"),
DEVINET_SYSCTL_FLUSHING_ENTRY(DROP_UNICAST_IN_L2_MULTICAST,
"drop_unicast_in_l2_multicast"),
+ DEVINET_SYSCTL_RW_ENTRY(LINKFILTER, "link_filter"),
},
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5716,6 +5716,7 @@ static void ipv6_store_devconf(const struct ipv6_devconf *cnf,
READ_ONCE(cnf->accept_untracked_na);
array[DEVCONF_ACCEPT_RA_MIN_LFT] = READ_ONCE(cnf->accept_ra_min_lft);
array[DEVCONF_FORCE_FORWARDING] = READ_ONCE(cnf->force_forwarding);
+ array[DEVCONF_LINK_FILTER] = READ_ONCE(cnf->link_filter);
}
static inline size_t inet6_ifla6_size(void)
@@ -7251,6 +7252,13 @@ static const struct ctl_table addrconf_sysctl[] = {
.extra1 = (void *)SYSCTL_ZERO,
.extra2 = (void *)SYSCTL_ONE,
},
+ {
+ .procname = "link_filter",
+ .data = &ipv6_devconf.link_filter,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{
.procname = "ioam6_id",
.data = &ipv6_devconf.ioam6_id,
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -714,6 +714,14 @@ static inline void rt6_probe(struct fib6_nh *fib6_nh)
}
#endif
+static inline int rt6_link_filter(const struct fib6_nh *nh)
+{
+ const struct net_device *dev = nh->fib_nh_dev;
+ int linkf = __in6_dev_get(dev)->cnf.link_filter;
+ return (linkf && !netif_running(dev))
+ || (linkf > 1 && !netif_carrier_ok(dev));
+}
+
/*
* Default Router Selection (RFC 2461 6.3.6)
*/
@@ -755,6 +763,8 @@ static int rt6_score_route(const struct fib6_nh *nh, u32 fib6_flags, int oif,
if (!m && (strict & RT6_LOOKUP_F_IFACE))
return RT6_NUD_FAIL_HARD;
+ if (rt6_link_filter(nh))
+ return -1;
#ifdef CONFIG_IPV6_ROUTER_PREF
m |= IPV6_DECODE_PREF(IPV6_EXTRACT_PREF(fib6_flags)) << 2;
#endif
--
2.39.5
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