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-rw-r--r--Documentation/networking/ip-sysctl.rst20
-rw-r--r--include/net/netns/ipv4.h2
-rw-r--r--net/ipv4/af_inet.c2
-rw-r--r--net/ipv4/fib_trie.c27
-rw-r--r--net/ipv4/sysctl_net_ipv4.c9
5 files changed, 60 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 2685ec161060..b0e800e68366 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -178,6 +178,26 @@ min_adv_mss - INTEGER
The advertised MSS depends on the first hop route MTU, but will
never be lower than this setting.
+fib_notify_on_flag_change - INTEGER
+ Whether to emit RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/
+ RTM_F_TRAP flags are changed.
+
+ After installing a route to the kernel, user space receives an
+ acknowledgment, which means the route was installed in the kernel,
+ but not necessarily in hardware.
+ It is also possible for a route already installed in hardware to change
+ its action and therefore its flags. For example, a host route that is
+ trapping packets can be "promoted" to perform decapsulation following
+ the installation of an IPinIP/VXLAN tunnel.
+ The notifications will indicate to user-space the state of the route.
+
+ Default: 0 (Do not emit notifications.)
+
+ Possible values:
+
+ - 0 - Do not emit notifications.
+ - 1 - Emit notifications.
+
IP Fragmentation:
ipfrag_high_thresh - LONG INTEGER
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 8e4fcac4df72..70a2a085dd1a 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -188,6 +188,8 @@ struct netns_ipv4 {
int sysctl_udp_wmem_min;
int sysctl_udp_rmem_min;
+ int sysctl_fib_notify_on_flag_change;
+
#ifdef CONFIG_NET_L3_MASTER_DEV
int sysctl_udp_l3mdev_accept;
#endif
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index b94fa8eb831b..ab42f6404fc6 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1871,6 +1871,8 @@ static __net_init int inet_init_net(struct net *net)
net->ipv4.sysctl_igmp_llm_reports = 1;
net->ipv4.sysctl_igmp_qrv = 2;
+ net->ipv4.sysctl_fib_notify_on_flag_change = 0;
+
return 0;
}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 28117c05dc35..60559b708158 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1038,6 +1038,8 @@ fib_find_matching_alias(struct net *net, const struct fib_rt_info *fri)
void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
{
struct fib_alias *fa_match;
+ struct sk_buff *skb;
+ int err;
rcu_read_lock();
@@ -1045,9 +1047,34 @@ void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
if (!fa_match)
goto out;
+ if (fa_match->offload == fri->offload && fa_match->trap == fri->trap)
+ goto out;
+
fa_match->offload = fri->offload;
fa_match->trap = fri->trap;
+ if (!net->ipv4.sysctl_fib_notify_on_flag_change)
+ goto out;
+
+ skb = nlmsg_new(fib_nlmsg_size(fa_match->fa_info), GFP_ATOMIC);
+ if (!skb) {
+ err = -ENOBUFS;
+ goto errout;
+ }
+
+ err = fib_dump_info(skb, 0, 0, RTM_NEWROUTE, fri, 0);
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(skb);
+ goto errout;
+ }
+
+ rtnl_notify(skb, net, 0, RTNLGRP_IPV4_ROUTE, NULL, GFP_ATOMIC);
+ goto out;
+
+errout:
+ rtnl_set_sk_err(net, RTNLGRP_IPV4_ROUTE, err);
out:
rcu_read_unlock();
}
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3e5f4f2e705e..e5798b3b59d2 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -1354,6 +1354,15 @@ static struct ctl_table ipv4_net_table[] = {
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE
},
+ {
+ .procname = "fib_notify_on_flag_change",
+ .data = &init_net.ipv4.sysctl_fib_notify_on_flag_change,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
{ }
};