netfilter: flowtable: refresh flow if hardware offload fails

If nf_flow_offload_add() fails to add the flow to hardware, then the
NF_FLOW_HW_REFRESH flag bit is set and the flow remains in the flowtable
software path.

If flowtable hardware offload is enabled, this patch enqueues a new
request to offload this flow to hardware.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
index 9ee1eae..e0f709d 100644 (file)
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -95,6 +95,7 @@ enum nf_flow_flags {
        NF_FLOW_HW,
        NF_FLOW_HW_DYING,
        NF_FLOW_HW_DEAD,
+       NF_FLOW_HW_REFRESH,
 };
 
 enum flow_offload_type {

diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index e919baf..7e91989 100644 (file)
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -243,8 +243,10 @@ int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
                return err;
        }
 
-       if (nf_flowtable_hw_offload(flow_table))
+       if (nf_flowtable_hw_offload(flow_table)) {
+               __set_bit(NF_FLOW_HW, &flow->flags);
                nf_flow_offload_add(flow_table, flow);
+       }
 
        return 0;
 }

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index f4ccb5f..9e563fd 100644 (file)
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -232,6 +232,13 @@ static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
        return NF_STOLEN;
 }
 
+static bool nf_flow_offload_refresh(struct nf_flowtable *flow_table,
+                                   struct flow_offload *flow)
+{
+       return nf_flowtable_hw_offload(flow_table) &&
+              test_and_clear_bit(NF_FLOW_HW_REFRESH, &flow->flags);
+}
+
 unsigned int
 nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
                        const struct nf_hook_state *state)
@@ -272,6 +279,9 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
        if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff))
                return NF_ACCEPT;
 
+       if (unlikely(nf_flow_offload_refresh(flow_table, flow)))
+               nf_flow_offload_add(flow_table, flow);
+
        if (nf_flow_offload_dst_check(&rt->dst)) {
                flow_offload_teardown(flow);
                return NF_ACCEPT;
@@ -498,6 +508,9 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
                                sizeof(*ip6h)))
                return NF_ACCEPT;
 
+       if (unlikely(nf_flow_offload_refresh(flow_table, flow)))
+               nf_flow_offload_add(flow_table, flow);
+
        if (nf_flow_offload_dst_check(&rt->dst)) {
                flow_offload_teardown(flow);
                return NF_ACCEPT;

diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
index b4c79fb..77b129f 100644 (file)
--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -654,20 +654,20 @@ static int flow_offload_rule_add(struct flow_offload_work *offload,
        return 0;
 }
 
-static int flow_offload_work_add(struct flow_offload_work *offload)
+static void flow_offload_work_add(struct flow_offload_work *offload)
 {
        struct nf_flow_rule *flow_rule[FLOW_OFFLOAD_DIR_MAX];
        int err;
 
        err = nf_flow_offload_alloc(offload, flow_rule);
        if (err < 0)
-               return -ENOMEM;
+               return;
 
        err = flow_offload_rule_add(offload, flow_rule);
+       if (err < 0)
+               set_bit(NF_FLOW_HW_REFRESH, &offload->flow->flags);
 
        nf_flow_offload_destroy(flow_rule);
-
-       return err;
 }
 
 static void flow_offload_work_del(struct flow_offload_work *offload)
@@ -712,7 +712,6 @@ static void flow_offload_work_handler(struct work_struct *work)
 {
        struct flow_offload_work *offload, *next;
        LIST_HEAD(offload_pending_list);
-       int ret;
 
        spin_lock_bh(&flow_offload_pending_list_lock);
        list_replace_init(&flow_offload_pending_list, &offload_pending_list);
@@ -721,9 +720,7 @@ static void flow_offload_work_handler(struct work_struct *work)
        list_for_each_entry_safe(offload, next, &offload_pending_list, list) {
                switch (offload->cmd) {
                case FLOW_CLS_REPLACE:
-                       ret = flow_offload_work_add(offload);
-                       if (ret < 0)
-                               __clear_bit(NF_FLOW_HW, &offload->flow->flags);
+                       flow_offload_work_add(offload);
                        break;
                case FLOW_CLS_DESTROY:
                        flow_offload_work_del(offload);
@@ -776,7 +773,6 @@ void nf_flow_offload_add(struct nf_flowtable *flowtable,
        if (!offload)
                return;
 
-       __set_bit(NF_FLOW_HW, &flow->flags);
        flow_offload_queue_work(offload);
 }