net, xdp: Introduce __xdp_build_skb_from_frame utility routine

Introduce __xdp_build_skb_from_frame utility routine to build
the skb from xdp_frame. Rely on __xdp_build_skb_from_frame in
cpumap code.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/4f9f4c6b3dd3933770c617eb6689dbc0c6e25863.1610475660.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 0cf3976..689206d 100644 (file)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -164,6 +164,9 @@ void xdp_warn(const char *msg, const char *func, const int line);
 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
 
 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
+struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
+                                          struct sk_buff *skb,
+                                          struct net_device *dev);
 
 static inline
 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)

diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 7473136..5d1469d 100644 (file)
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -141,49 +141,6 @@ static void cpu_map_kthread_stop(struct work_struct *work)
        kthread_stop(rcpu->kthread);
 }
 
-static struct sk_buff *cpu_map_build_skb(struct xdp_frame *xdpf,
-                                        struct sk_buff *skb)
-{
-       unsigned int hard_start_headroom;
-       unsigned int frame_size;
-       void *pkt_data_start;
-
-       /* Part of headroom was reserved to xdpf */
-       hard_start_headroom = sizeof(struct xdp_frame) +  xdpf->headroom;
-
-       /* Memory size backing xdp_frame data already have reserved
-        * room for build_skb to place skb_shared_info in tailroom.
-        */
-       frame_size = xdpf->frame_sz;
-
-       pkt_data_start = xdpf->data - hard_start_headroom;
-       skb = build_skb_around(skb, pkt_data_start, frame_size);
-       if (unlikely(!skb))
-               return NULL;
-
-       skb_reserve(skb, hard_start_headroom);
-       __skb_put(skb, xdpf->len);
-       if (xdpf->metasize)
-               skb_metadata_set(skb, xdpf->metasize);
-
-       /* Essential SKB info: protocol and skb->dev */
-       skb->protocol = eth_type_trans(skb, xdpf->dev_rx);
-
-       /* Optional SKB info, currently missing:
-        * - HW checksum info           (skb->ip_summed)
-        * - HW RX hash                 (skb_set_hash)
-        * - RX ring dev queue index    (skb_record_rx_queue)
-        */
-
-       /* Until page_pool get SKB return path, release DMA here */
-       xdp_release_frame(xdpf);
-
-       /* Allow SKB to reuse area used by xdp_frame */
-       xdp_scrub_frame(xdpf);
-
-       return skb;
-}
-
 static void __cpu_map_ring_cleanup(struct ptr_ring *ring)
 {
        /* The tear-down procedure should have made sure that queue is
@@ -350,7 +307,8 @@ static int cpu_map_kthread_run(void *data)
                        struct sk_buff *skb = skbs[i];
                        int ret;
 
-                       skb = cpu_map_build_skb(xdpf, skb);
+                       skb = __xdp_build_skb_from_frame(xdpf, skb,
+                                                        xdpf->dev_rx);
                        if (!skb) {
                                xdp_return_frame(xdpf);
                                continue;

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 3a8c9ab..aeb09ed 100644 (file)
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -513,3 +513,47 @@ void xdp_warn(const char *msg, const char *func, const int line)
        WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg);
 };
 EXPORT_SYMBOL_GPL(xdp_warn);
+
+struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
+                                          struct sk_buff *skb,
+                                          struct net_device *dev)
+{
+       unsigned int headroom, frame_size;
+       void *hard_start;
+
+       /* Part of headroom was reserved to xdpf */
+       headroom = sizeof(*xdpf) + xdpf->headroom;
+
+       /* Memory size backing xdp_frame data already have reserved
+        * room for build_skb to place skb_shared_info in tailroom.
+        */
+       frame_size = xdpf->frame_sz;
+
+       hard_start = xdpf->data - headroom;
+       skb = build_skb_around(skb, hard_start, frame_size);
+       if (unlikely(!skb))
+               return NULL;
+
+       skb_reserve(skb, headroom);
+       __skb_put(skb, xdpf->len);
+       if (xdpf->metasize)
+               skb_metadata_set(skb, xdpf->metasize);
+
+       /* Essential SKB info: protocol and skb->dev */
+       skb->protocol = eth_type_trans(skb, dev);
+
+       /* Optional SKB info, currently missing:
+        * - HW checksum info           (skb->ip_summed)
+        * - HW RX hash                 (skb_set_hash)
+        * - RX ring dev queue index    (skb_record_rx_queue)
+        */
+
+       /* Until page_pool get SKB return path, release DMA here */
+       xdp_release_frame(xdpf);
+
+       /* Allow SKB to reuse area used by xdp_frame */
+       xdp_scrub_frame(xdpf);
+
+       return skb;
+}
+EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);