For zerocopy mode, tx_desc->addr can point to an arbitrary offset
and carry some TX metadata in the headroom. For copy mode, there
is no way currently to populate skb metadata.
Introduce new tx_metadata_len umem config option that indicates how many
bytes to treat as metadata. Metadata bytes come prior to tx_desc address
(same as in RX case).
The size of the metadata has mostly the same constraints as XDP:
- less than 256 bytes
- 8-byte aligned (compared to 4-byte alignment on xdp, due to 8-byte
timestamp in the completion)
- non-zero
This data is not interpreted in any way right now.
Reviewed-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>
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/xdp_umem.c | 4 ++++
net/xdp/xsk.c | 12 +++++++++++-
net/xdp/xsk_buff_pool.c | 1 +
net/xdp/xsk_queue.h | 17 ++++++++++-------
tools/include/uapi/linux/if_xdp.h | 1 +
8 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index f83128007fb0..bcf765124f72 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -30,6 +30,7 @@ struct xdp_umem {
struct user_struct *user;
refcount_t users;
u8 flags;
+ u8 tx_metadata_len;
bool zc;
struct page **pgs;
int id;
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index b0bdff26fc88..1985ffaf9b0c 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -77,6 +77,7 @@ struct xsk_buff_pool {
u32 chunk_size;
u32 chunk_shift;
u32 frame_len;
+ u8 tx_metadata_len; /* inherited from umem */
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 8d48863472b9..2ecf79282c26 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -76,6 +76,7 @@ struct xdp_umem_reg {
__u32 chunk_size;
__u32 headroom;
__u32 flags;
+ __u32 tx_metadata_len;
};
struct xdp_statistics {
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 06cead2b8e34..946a687fb8e8 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
return -EINVAL;
+ if (mr->tx_metadata_len >= 256 || mr->tx_metadata_len % 8)
+ return -EINVAL;
+
umem->size = size;
umem->headroom = headroom;
umem->chunk_size = chunk_size;
@@ -207,6 +210,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
umem->pgs = NULL;
umem->user = NULL;
umem->flags = mr->flags;
+ umem->tx_metadata_len = mr->tx_metadata_len;
INIT_LIST_HEAD(&umem->xsk_dma_list);
refcount_set(&umem->users, 1);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ae9f8cb611f6..c904356e2800 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -1283,6 +1283,14 @@ struct xdp_umem_reg_v1 {
__u32 headroom;
};
+struct xdp_umem_reg_v2 {
+ __u64 addr; /* Start of packet data area */
+ __u64 len; /* Length of packet data area */
+ __u32 chunk_size;
+ __u32 headroom;
+ __u32 flags;
+};
+
static int xsk_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
@@ -1326,8 +1334,10 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
if (optlen < sizeof(struct xdp_umem_reg_v1))
return -EINVAL;
- else if (optlen < sizeof(mr))
+ else if (optlen < sizeof(struct xdp_umem_reg_v2))
mr_size = sizeof(struct xdp_umem_reg_v1);
+ else if (optlen < sizeof(mr))
+ mr_size = sizeof(struct xdp_umem_reg_v2);
if (copy_from_sockptr(&mr, optval, mr_size))
return -EFAULT;
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 49cb9f9a09be..386eddcdf837 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 = umem->tx_metadata_len;
INIT_LIST_HEAD(&pool->free_list);
INIT_LIST_HEAD(&pool->xskb_list);
INIT_LIST_HEAD(&pool->xsk_tx_list);
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 13354a1e4280..c74a1372bcb9 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -143,15 +143,17 @@ static inline bool xp_unused_options_set(u32 options)
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 len = desc->len + pool->tx_metadata_len;
+ u64 offset = addr & (pool->chunk_size - 1);
if (!desc->len)
return false;
- if (offset + desc->len > pool->chunk_size)
+ if (offset + len > pool->chunk_size)
return false;
- if (desc->addr >= pool->addrs_cnt)
+ if (addr >= pool->addrs_cnt)
return false;
if (xp_unused_options_set(desc->options))
@@ -162,16 +164,17 @@ 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;
+ u64 len = desc->len + pool->tx_metadata_len;
if (!desc->len)
return false;
- if (desc->len > pool->chunk_size)
+ if (len > pool->chunk_size)
return false;
- if (addr >= pool->addrs_cnt || addr + desc->len > pool->addrs_cnt ||
- xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
+ if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
+ xp_desc_crosses_non_contig_pg(pool, addr, len))
return false;
if (xp_unused_options_set(desc->options))
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index 73a47da885dc..34411a2e5b6c 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -76,6 +76,7 @@ struct xdp_umem_reg {
__u32 chunk_size;
__u32 headroom;
__u32 flags;
+ __u32 tx_metadata_len;
};
struct xdp_statistics {
--
2.43.0.rc1.413.gea7ed67945-goog
