| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250430201120.1794658-1-jon@nutanix.com>
Date: Wed, 30 Apr 2025 13:11:18 -0700
From: Jon Kohler <jon@...anix.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>,
Jason Wang <jasowang@...hat.com>, Andrew Lunn <andrew+netdev@...n.ch>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Jesper Dangaard Brouer <hawk@...nel.org>,
John Fastabend <john.fastabend@...il.com>,
Simon Horman <horms@...nel.org>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, bpf@...r.kernel.org
Cc: Jon Kohler <jon@...anix.com>
Subject: [PATCH net-next v2] xdp: Add helpers for head length, headroom, and metadata length
Introduce new XDP helpers:
- xdp_headlen: Similar to skb_headlen
- xdp_headroom: Similar to skb_headroom
- xdp_metadata_len: Similar to skb_metadata_len
Integrate these helpers into tap, tun, and XDP implementation to start.
No functional changes introduced.
Signed-off-by: Jon Kohler <jon@...anix.com>
---
v1->v2: Integrate feedback from Willem
https://patchwork.kernel.org/project/netdevbpf/patch/20250430182921.1704021-1-jon@nutanix.com/
drivers/net/tap.c | 6 +++---
drivers/net/tun.c | 12 +++++------
include/net/xdp.h | 54 +++++++++++++++++++++++++++++++++++++++++++----
net/core/xdp.c | 12 +++++------
4 files changed, 65 insertions(+), 19 deletions(-)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index d4ece538f1b2..a62fbca4b08f 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1048,7 +1048,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
struct sk_buff *skb;
int err, depth;
- if (unlikely(xdp->data_end - xdp->data < ETH_HLEN)) {
+ if (unlikely(xdp_headlen(xdp) < ETH_HLEN)) {
err = -EINVAL;
goto err;
}
@@ -1062,8 +1062,8 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
goto err;
}
- skb_reserve(skb, xdp->data - xdp->data_hard_start);
- skb_put(skb, xdp->data_end - xdp->data);
+ skb_reserve(skb, xdp_headroom(xdp));
+ skb_put(skb, xdp_headlen(xdp));
skb_set_network_header(skb, ETH_HLEN);
skb_reset_mac_header(skb);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 7babd1e9a378..4c47eed71986 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1567,7 +1567,7 @@ static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
dev_core_stats_rx_dropped_inc(tun->dev);
return err;
}
- dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
+ dev_sw_netstats_rx_add(tun->dev, xdp_headlen(xdp));
break;
case XDP_TX:
err = tun_xdp_tx(tun->dev, xdp);
@@ -1575,7 +1575,7 @@ static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
dev_core_stats_rx_dropped_inc(tun->dev);
return err;
}
- dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
+ dev_sw_netstats_rx_add(tun->dev, xdp_headlen(xdp));
break;
case XDP_PASS:
break;
@@ -2355,7 +2355,7 @@ static int tun_xdp_one(struct tun_struct *tun,
struct xdp_buff *xdp, int *flush,
struct tun_page *tpage)
{
- unsigned int datasize = xdp->data_end - xdp->data;
+ unsigned int datasize = xdp_headlen(xdp);
struct tun_xdp_hdr *hdr = xdp->data_hard_start;
struct virtio_net_hdr *gso = &hdr->gso;
struct bpf_prog *xdp_prog;
@@ -2415,14 +2415,14 @@ static int tun_xdp_one(struct tun_struct *tun,
goto out;
}
- skb_reserve(skb, xdp->data - xdp->data_hard_start);
- skb_put(skb, xdp->data_end - xdp->data);
+ skb_reserve(skb, xdp_headroom(xdp));
+ skb_put(skb, xdp_headlen(xdp));
/* The externally provided xdp_buff may have no metadata support, which
* is marked by xdp->data_meta being xdp->data + 1. This will lead to a
* metasize of -1 and is the reason why the condition checks for > 0.
*/
- metasize = xdp->data - xdp->data_meta;
+ metasize = xdp_metadata_len(xdp);
if (metasize > 0)
skb_metadata_set(skb, metasize);
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 48efacbaa35d..044345b18305 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -151,10 +151,56 @@ xdp_get_shared_info_from_buff(const struct xdp_buff *xdp)
return (struct skb_shared_info *)xdp_data_hard_end(xdp);
}
+/**
+ * xdp_headlen - Calculate the length of the data in an XDP buffer
+ * @xdp: Pointer to the XDP buffer structure
+ *
+ * Compute the length of the data contained in the XDP buffer. Does not
+ * include frags, use xdp_get_buff_len() for that instead.
+ *
+ * Analogous to skb_headlen().
+ *
+ * Return: The length of the data in the XDP buffer in bytes.
+ */
+static inline unsigned int xdp_headlen(const struct xdp_buff *xdp)
+{
+ return xdp->data_end - xdp->data;
+}
+
+/**
+ * xdp_headroom - Calculate the headroom available in an XDP buffer
+ * @xdp: Pointer to the XDP buffer structure
+ *
+ * Compute the headroom in an XDP buffer.
+ *
+ * Analogous to the skb_headroom().
+ *
+ * Return: The size of the headroom in bytes.
+ */
+static inline unsigned int xdp_headroom(const struct xdp_buff *xdp)
+{
+ return xdp->data - xdp->data_hard_start;
+}
+
+/**
+ * xdp_metadata_len - Calculate the length of metadata in an XDP buffer
+ * @xdp: Pointer to the XDP buffer structure
+ *
+ * Compute the length of the metadata region in an XDP buffer.
+ *
+ * Analogous to skb_metadata_len().
+ *
+ * Return: The length of the metadata in bytes.
+ */
+static inline unsigned int xdp_metadata_len(const struct xdp_buff *xdp)
+{
+ return xdp->data - xdp->data_meta;
+}
+
static __always_inline unsigned int
xdp_get_buff_len(const struct xdp_buff *xdp)
{
- unsigned int len = xdp->data_end - xdp->data;
+ unsigned int len = xdp_headlen(xdp);
const struct skb_shared_info *sinfo;
if (likely(!xdp_buff_has_frags(xdp)))
@@ -364,8 +410,8 @@ int xdp_update_frame_from_buff(const struct xdp_buff *xdp,
int metasize, headroom;
/* Assure headroom is available for storing info */
- headroom = xdp->data - xdp->data_hard_start;
- metasize = xdp->data - xdp->data_meta;
+ headroom = xdp_headroom(xdp);
+ metasize = xdp_metadata_len(xdp);
metasize = metasize > 0 ? metasize : 0;
if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
return -ENOSPC;
@@ -377,7 +423,7 @@ int xdp_update_frame_from_buff(const struct xdp_buff *xdp,
}
xdp_frame->data = xdp->data;
- xdp_frame->len = xdp->data_end - xdp->data;
+ xdp_frame->len = xdp_headlen(xdp);
xdp_frame->headroom = headroom - sizeof(*xdp_frame);
xdp_frame->metasize = metasize;
xdp_frame->frame_sz = xdp->frame_sz;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index f86eedad586a..0d56320a7ff9 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -581,8 +581,8 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
/* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
metasize = xdp_data_meta_unsupported(xdp) ? 0 :
- xdp->data - xdp->data_meta;
- totsize = xdp->data_end - xdp->data + metasize;
+ xdp_metadata_len(xdp);
+ totsize = xdp_headlen(xdp) + metasize;
if (sizeof(*xdpf) + totsize > PAGE_SIZE)
return NULL;
@@ -646,10 +646,10 @@ struct sk_buff *xdp_build_skb_from_buff(const struct xdp_buff *xdp)
if (unlikely(!skb))
return NULL;
- skb_reserve(skb, xdp->data - xdp->data_hard_start);
- __skb_put(skb, xdp->data_end - xdp->data);
+ skb_reserve(skb, xdp_headroom(xdp));
+ __skb_put(skb, xdp_headlen(xdp));
- metalen = xdp->data - xdp->data_meta;
+ metalen = xdp_metadata_len(xdp);
if (metalen > 0)
skb_metadata_set(skb, metalen);
@@ -763,7 +763,7 @@ struct sk_buff *xdp_build_skb_from_zc(struct xdp_buff *xdp)
memcpy(__skb_put(skb, len), xdp->data_meta, LARGEST_ALIGN(len));
- metalen = xdp->data - xdp->data_meta;
+ metalen = xdp_metadata_len(xdp);
if (metalen > 0) {
skb_metadata_set(skb, metalen);
__skb_pull(skb, metalen);
--
2.43.0
Powered by blists - more mailing lists