IPv4: Add "offload failed" indication to routes

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.

The asynchronous nature of route installation in hardware can lead to a
routing daemon advertising a route before it was actually installed in
hardware. This can result in packet loss or mis-routed packets until the
route is installed in hardware.

To avoid such cases, previous patch set added the ability to emit
RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/RTM_F_TRAP flags
are changed, this behavior is controlled by sysctl.

With the above mentioned behavior, it is possible to know from user-space
if the route was offloaded, but if the offload fails there is no indication
to user-space. Following a failure, a routing daemon will wait indefinitely
for a notification that will never come.

This patch adds an "offload_failed" indication to IPv4 routes, so that
users will have better visibility into the offload process.

'struct fib_alias', and 'struct fib_rt_info' are extended with new field
that indicates if route offload failed. Note that the new field is added
using unused bit and therefore there is no need to increase structs size.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index cf111e73f81e77adc58fbf6c1099663eaea25543..ac9a174372cccfad765b6d564d7b2a76b13d88fe 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -4963,6 +4963,7 @@ mlxsw_sp_fib4_entry_hw_flags_set(struct mlxsw_sp *mlxsw_sp,
        fri.type = fib4_entry->type;
        fri.offload = should_offload;
        fri.trap = !should_offload;
+       fri.offload_failed = false;
        fib_alias_hw_flags_set(mlxsw_sp_net(mlxsw_sp), &fri);
 }
 
@@ -4985,6 +4986,7 @@ mlxsw_sp_fib4_entry_hw_flags_clear(struct mlxsw_sp *mlxsw_sp,
        fri.type = fib4_entry->type;
        fri.offload = false;
        fri.trap = false;
+       fri.offload_failed = false;
        fib_alias_hw_flags_set(mlxsw_sp_net(mlxsw_sp), &fri);
 }
 

diff --git a/drivers/net/netdevsim/fib.c b/drivers/net/netdevsim/fib.c
index 1779146926a5778f52ad955da748c9e8ffcbd569..ca19da169853871f5c42b4e30530b7ddc60e4cfd 100644 (file)
--- a/drivers/net/netdevsim/fib.c
+++ b/drivers/net/netdevsim/fib.c
@@ -319,6 +319,7 @@ static void nsim_fib4_rt_hw_flags_set(struct net *net,
        fri.type = fib4_rt->type;
        fri.offload = false;
        fri.trap = trap;
+       fri.offload_failed = false;
        fib_alias_hw_flags_set(net, &fri);
 }
 

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 2ec062aaa9782b71cfd75279c8347d90cff14e81..a914f33f3ed55ef14a47f279788fae1eb8cad4ce 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -213,7 +213,8 @@ struct fib_rt_info {
        u8                      type;
        u8                      offload:1,
                                trap:1,
-                               unused:6;
+                               offload_failed:1,
+                               unused:5;
 };
 
 struct fib_entry_notifier_info {

diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h
index aff454ef0fa38e38a20da42d7cf8d08389a0fc0e..b58db1ca4bfb3be954b810f31e1147de36b28deb 100644 (file)
--- a/net/ipv4/fib_lookup.h
+++ b/net/ipv4/fib_lookup.h
@@ -18,7 +18,8 @@ struct fib_alias {
        s16                     fa_default;
        u8                      offload:1,
                                trap:1,
-                               unused:6;
+                               offload_failed:1,
+                               unused:5;
        struct rcu_head         rcu;
 };
 

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 4c38facf91c0f4ce307fccd6668973a6caf4e916..a632b66bc13abbd0ef4de1559182a21fd8701fde 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -521,6 +521,7 @@ void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
        fri.type = fa->fa_type;
        fri.offload = fa->offload;
        fri.trap = fa->trap;
+       fri.offload_failed = fa->offload_failed;
        err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
@@ -1811,6 +1812,8 @@ offload:
                rtm->rtm_flags |= RTM_F_OFFLOAD;
        if (fri->trap)
                rtm->rtm_flags |= RTM_F_TRAP;
+       if (fri->offload_failed)
+               rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
 
        nlmsg_end(skb, nlh);
        return 0;

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 60559b7081589c0c14802daa56b7216e0bc1912d..80147caa9bfd3d229cb2f9f551e5328145560657 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1047,11 +1047,13 @@ 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)
+       if (fa_match->offload == fri->offload && fa_match->trap == fri->trap &&
+           fa_match->offload_failed == fri->offload_failed)
                goto out;
 
        fa_match->offload = fri->offload;
        fa_match->trap = fri->trap;
+       fa_match->offload_failed = fri->offload_failed;
 
        if (!net->ipv4.sysctl_fib_notify_on_flag_change)
                goto out;
@@ -1290,6 +1292,7 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
                        new_fa->fa_default = -1;
                        new_fa->offload = 0;
                        new_fa->trap = 0;
+                       new_fa->offload_failed = 0;
 
                        hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
 
@@ -1350,6 +1353,7 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
        new_fa->fa_default = -1;
        new_fa->offload = 0;
        new_fa->trap = 0;
+       new_fa->offload_failed = 0;
 
        /* Insert new entry to the list. */
        err = fib_insert_alias(t, tp, l, new_fa, fa, key);
@@ -2289,6 +2293,7 @@ static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
                                fri.type = fa->fa_type;
                                fri.offload = fa->offload;
                                fri.trap = fa->trap;
+                               fri.offload_failed = fa->offload_failed;
                                err = fib_dump_info(skb,
                                                    NETLINK_CB(cb->skb).portid,
                                                    cb->nlh->nlmsg_seq,

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index be31e2446470c9ed016def4f6053efbc8f9a04bf..02d81d79deeb1a3d8f103f87918d211019940085 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3304,6 +3304,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
                fri.type = rt->rt_type;
                fri.offload = 0;
                fri.trap = 0;
+               fri.offload_failed = 0;
                if (res.fa_head) {
                        struct fib_alias *fa;