For zerocopy mode, tx_desc->addr can point to the arbitrary offset
and carry some TX metadata in the headroom. For copy mode, there
is no way currently to populate skb metadata.
Introduce new XDP_TX_METADATA_LEN that indicates how many bytes
to treat as metadata. Metadata bytes come prior to tx_desc address
(same as in RX case).
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
include/net/xdp_sock.h | 1 +
include/net/xsk_buff_pool.h | 1 +
include/uapi/linux/if_xdp.h | 1 +
net/xdp/xsk.c | 31 ++++++++++++++++++++++++++++++-
net/xdp/xsk_buff_pool.c | 1 +
net/xdp/xsk_queue.h | 7 ++++---
6 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index e96a1151ec75..30018b3b862d 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -51,6 +51,7 @@ struct xdp_sock {
struct list_head flush_node;
struct xsk_buff_pool *pool;
u16 queue_id;
+ u8 tx_metadata_len;
bool zc;
enum {
XSK_READY = 0,
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index a8d7b8a3688a..751fea51a6af 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -75,6 +75,7 @@ struct xsk_buff_pool {
u32 chunk_size;
u32 chunk_shift;
u32 frame_len;
+ u8 tx_metadata_len; /* inherited from xsk_sock */
u8 cached_need_wakeup;
bool uses_need_wakeup;
bool dma_need_sync;
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index a78a8096f4ce..2374eafff7db 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -63,6 +63,7 @@ struct xdp_mmap_offsets {
#define XDP_UMEM_COMPLETION_RING 6
#define XDP_STATISTICS 7
#define XDP_OPTIONS 8
+#define XDP_TX_METADATA_LEN 9
struct xdp_umem_reg {
__u64 addr; /* Start of packet data area */
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index cc1e7f15fa73..c9b2daba7b6d 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -485,6 +485,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
int err;
hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom));
+ hr = max(hr, L1_CACHE_ALIGN((u32)xs->tx_metadata_len));
tr = dev->needed_tailroom;
len = desc->len;
@@ -493,14 +494,21 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
return ERR_PTR(err);
skb_reserve(skb, hr);
- skb_put(skb, len);
+ skb_put(skb, len + xs->tx_metadata_len);
buffer = xsk_buff_raw_get_data(xs->pool, desc->addr);
+ buffer -= xs->tx_metadata_len;
+
err = skb_store_bits(skb, 0, buffer, len);
if (unlikely(err)) {
kfree_skb(skb);
return ERR_PTR(err);
}
+
+ if (xs->tx_metadata_len) {
+ skb_metadata_set(skb, xs->tx_metadata_len);
+ __skb_pull(skb, xs->tx_metadata_len);
+ }
}
skb->dev = dev;
@@ -1137,6 +1145,27 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
mutex_unlock(&xs->mutex);
return err;
}
+ case XDP_TX_METADATA_LEN:
+ {
+ int val;
+
+ if (optlen < sizeof(val))
+ return -EINVAL;
+ if (copy_from_sockptr(&val, optval, sizeof(val)))
+ return -EFAULT;
+
+ if (val >= 256)
+ return -EINVAL;
+
+ mutex_lock(&xs->mutex);
+ if (xs->state != XSK_READY) {
+ mutex_unlock(&xs->mutex);
+ return -EBUSY;
+ }
+ xs->tx_metadata_len = val;
+ mutex_unlock(&xs->mutex);
+ return err;
+ }
default:
break;
}
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 26f6d304451e..66ff9c345a67 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
XDP_PACKET_HEADROOM;
pool->umem = umem;
pool->addrs = umem->addrs;
+ pool->tx_metadata_len = xs->tx_metadata_len;
INIT_LIST_HEAD(&pool->free_list);
INIT_LIST_HEAD(&pool->xsk_tx_list);
spin_lock_init(&pool->xsk_tx_list_lock);
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 6d40a77fccbe..c8d287c18d64 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -133,12 +133,13 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr)
static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
struct xdp_desc *desc)
{
- u64 offset = desc->addr & (pool->chunk_size - 1);
+ u64 addr = desc->addr - pool->tx_metadata_len;
+ u64 offset = addr & (pool->chunk_size - 1);
if (offset + desc->len > pool->chunk_size)
return false;
- if (desc->addr >= pool->addrs_cnt)
+ if (addr >= pool->addrs_cnt)
return false;
if (desc->options)
@@ -149,7 +150,7 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
struct xdp_desc *desc)
{
- u64 addr = xp_unaligned_add_offset_to_addr(desc->addr);
+ u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len;
if (desc->len > pool->chunk_size)
return false;
--
2.41.0.162.gfafddb0af9-goog
