Add FLOW_OFFLOAD_XMIT_DIRECT to turn on the direct dev_queue_xmit() path
to transmit ethernet frames. Cache the source and destination hardware
address for flow to use dev_queue_xmit() to transfer packets.

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
v2: no changes.

 include/net/netfilter/nf_flow_table.h |  5 +++++
 net/netfilter/nf_flow_table_core.c    |  2 ++
 net/netfilter/nf_flow_table_ip.c      | 24 ++++++++++++++++++++++++
 net/netfilter/nft_flow_offload.c      | 16 +++++++++++-----
 4 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/include/net/netfilter/nf_flow_table.h 
b/include/net/netfilter/nf_flow_table.h
index fe225e881cc7..1b57d1d1270d 100644
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -92,6 +92,7 @@ enum flow_offload_tuple_dir {
 enum flow_offload_xmit_type {
        FLOW_OFFLOAD_XMIT_NEIGH         = 0,
        FLOW_OFFLOAD_XMIT_XFRM,
+       FLOW_OFFLOAD_XMIT_DIRECT,
 };
 
 struct flow_offload_tuple {
@@ -119,6 +120,8 @@ struct flow_offload_tuple {
        u16                             mtu;
        u32                             oifidx;
 
+       u8                              h_source[ETH_ALEN];
+       u8                              h_dest[ETH_ALEN];
        struct dst_entry                *dst_cache;
 };
 
@@ -167,6 +170,8 @@ struct nf_flow_route {
                } in;
                struct {
                        u32             ifindex;
+                       u8              h_source[ETH_ALEN];
+                       u8              h_dest[ETH_ALEN];
                } out;
                struct dst_entry        *dst;
        } tuple[FLOW_OFFLOAD_DIR_MAX];
diff --git a/net/netfilter/nf_flow_table_core.c 
b/net/netfilter/nf_flow_table_core.c
index 99f01f08c550..725366339b85 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -94,6 +94,8 @@ static int flow_offload_fill_route(struct flow_offload *flow,
        }
 
        flow_tuple->iifidx = route->tuple[dir].in.ifindex;
+       memcpy(flow_tuple->h_dest, route->tuple[dir].out.h_dest, ETH_ALEN);
+       memcpy(flow_tuple->h_source, route->tuple[dir].out.h_source, ETH_ALEN);
        flow_tuple->oifidx = route->tuple[dir].out.ifindex;
 
        if (dst_xfrm(dst))
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 92f444db8d9f..1fa5c67cd914 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -247,6 +247,24 @@ static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
        return NF_STOLEN;
 }
 
+static unsigned int nf_flow_queue_xmit(struct sk_buff *skb,
+                                      struct net_device *outdev,
+                                      const struct flow_offload_tuple *tuple)
+{
+       struct ethhdr *eth;
+
+       skb->dev = outdev;
+       skb_push(skb, skb->mac_len);
+       skb_reset_mac_header(skb);
+
+       eth = eth_hdr(skb);
+       memcpy(eth->h_source, tuple->h_source, ETH_ALEN);
+       memcpy(eth->h_dest, tuple->h_dest, ETH_ALEN);
+       dev_queue_xmit(skb);
+
+       return NF_STOLEN;
+}
+
 unsigned int
 nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
                        const struct nf_hook_state *state)
@@ -325,6 +343,9 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
                IPCB(skb)->flags = IPSKB_FORWARDED;
                ret = nf_flow_xmit_xfrm(skb, state, &rt->dst);
                break;
+       case FLOW_OFFLOAD_XMIT_DIRECT:
+               ret = nf_flow_queue_xmit(skb, outdev, &tuplehash->tuple);
+               break;
        default:
                WARN_ON_ONCE(1);
                ret = NF_DROP;
@@ -581,6 +602,9 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
                IP6CB(skb)->flags = IP6SKB_FORWARDED;
                ret = nf_flow_xmit_xfrm(skb, state, &rt->dst);
                break;
+       case FLOW_OFFLOAD_XMIT_DIRECT:
+               ret = nf_flow_queue_xmit(skb, outdev, &tuplehash->tuple);
+               break;
        default:
                WARN_ON_ONCE(1);
                ret = NF_DROP;
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 6a6633e2ceeb..d440e436cb16 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -21,12 +21,11 @@ struct nft_flow_offload {
 
 static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
                                     const struct nf_conn *ct,
-                                    enum ip_conntrack_dir dir,
+                                    enum ip_conntrack_dir dir, u8 *dst,
                                     struct net_device_path_stack *stack)
 {
        const struct dst_entry *dst_cache = route->tuple[dir].dst;
        const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
-       unsigned char ha[ETH_ALEN];
        struct net_device *dev;
        struct neighbour *n;
        struct rtable *rt;
@@ -41,18 +40,20 @@ static int nft_dev_fill_forward_path(const struct 
nf_flow_route *route,
 
        read_lock_bh(&n->lock);
        nud_state = n->nud_state;
-       ether_addr_copy(ha, n->ha);
+       ether_addr_copy(dst, n->ha);
        read_unlock_bh(&n->lock);
        neigh_release(n);
 
        if (!(nud_state & NUD_VALID))
                return -1;
 
-       return dev_fill_forward_path(dev, ha, stack);
+       return dev_fill_forward_path(dev, dst, stack);
 }
 
 struct nft_forward_info {
        u32 iifindex;
+       u8 h_source[ETH_ALEN];
+       u8 h_dest[ETH_ALEN];
 };
 
 static int nft_dev_forward_path(struct nf_flow_route *route,
@@ -62,11 +63,12 @@ static int nft_dev_forward_path(struct nf_flow_route *route,
        struct net_device_path_stack stack = {};
        struct nft_forward_info info = {};
        struct net_device_path *path;
+       unsigned char dst[ETH_ALEN];
        int i, ret;
 
        memset(&stack, 0, sizeof(stack));
 
-       ret = nft_dev_fill_forward_path(route, ct, dir, &stack);
+       ret = nft_dev_fill_forward_path(route, ct, dir, dst, &stack);
        if (ret < 0)
                return -1;
 
@@ -74,6 +76,8 @@ static int nft_dev_forward_path(struct nf_flow_route *route,
                path = &stack.path[i];
                switch (path->type) {
                case DEV_PATH_ETHERNET:
+                       memcpy(info.h_dest, path->dev->dev_addr, ETH_ALEN);
+                       memcpy(info.h_source, dst, ETH_ALEN);
                        info.iifindex = path->dev->ifindex;
                        break;
                case DEV_PATH_VLAN:
@@ -84,6 +88,8 @@ static int nft_dev_forward_path(struct nf_flow_route *route,
        }
 
        route->tuple[!dir].in.ifindex = info.iifindex;
+       memcpy(route->tuple[dir].out.h_dest, info.h_source, ETH_ALEN);
+       memcpy(route->tuple[dir].out.h_source, info.h_dest, ETH_ALEN);
        route->tuple[dir].out.ifindex = info.iifindex;
 
        return 0;
-- 
2.20.1

Reply via email to