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Date: Wed, 20 Apr 2016 10:57:33 +0200
From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, roopa@...ulusnetworks.com,
eric.dumazet@...il.com, tgraf@...g.ch, jhs@...atatu.com,
Nicolas Dichtel <nicolas.dichtel@...nd.com>
Subject: [PATCH net-next 2/4] libnl: add more helpers to align attribute on 64-bit
Add use it to align IFLA_STATS64.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
---
include/net/netlink.h | 8 ++++
lib/nlattr.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
net/core/rtnetlink.c | 9 +----
3 files changed, 117 insertions(+), 7 deletions(-)
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 694caac31d2c..c01863b49787 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -244,13 +244,21 @@ int nla_memcpy(void *dest, const struct nlattr *src, int count);
int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
int nla_strcmp(const struct nlattr *nla, const char *str);
struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
+struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
+ int attrlen, int padattr);
void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
+struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
+ int attrlen, int padattr);
void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
const void *data);
+void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr);
void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
+int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr);
int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
int nla_append(struct sk_buff *skb, int attrlen, const void *data);
diff --git a/lib/nlattr.c b/lib/nlattr.c
index f5907d23272d..cc311b8b6ff0 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -355,6 +355,31 @@ struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
EXPORT_SYMBOL(__nla_reserve);
/**
+ * __nla_reserve_64bit - reserve room for attribute on the skb and align it
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it. It also ensure that this
+ * attribute will be 64-bit aign.
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
+ int attrlen, int padattr)
+{
+#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS
+ if (!IS_ALIGNED((unsigned long)skb->data, 8))
+ nla_align_64bit(skb, padattr);
+#endif
+
+ return __nla_reserve(skb, attrtype, attrlen);
+}
+EXPORT_SYMBOL(__nla_reserve_64bit);
+
+/**
* __nla_reserve_nohdr - reserve room for attribute without header
* @skb: socket buffer to reserve room on
* @attrlen: length of attribute payload
@@ -397,6 +422,38 @@ struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
EXPORT_SYMBOL(nla_reserve);
/**
+ * nla_reserve_64bit - reserve room for attribute on the skb and align it
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it. It also ensure that this
+ * attribute will be 64-bit aign.
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ int padattr)
+{
+ size_t len;
+
+#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS
+ if (!IS_ALIGNED((unsigned long)skb->data, 8))
+ len = nla_total_size_64bit(attrlen);
+ else
+#endif
+ len = nla_total_size(attrlen);
+
+ if (unlikely(skb_tailroom(skb) < len))
+ return NULL;
+
+ return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
+}
+EXPORT_SYMBOL(nla_reserve_64bit);
+
+/**
* nla_reserve_nohdr - reserve room for attribute without header
* @skb: socket buffer to reserve room on
* @attrlen: length of attribute payload
@@ -436,6 +493,26 @@ void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
EXPORT_SYMBOL(__nla_put);
/**
+ * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr)
+{
+ struct nlattr *nla;
+
+ nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
+ memcpy(nla_data(nla), data, attrlen);
+}
+EXPORT_SYMBOL(__nla_put_64bit);
+
+/**
* __nla_put_nohdr - Add a netlink attribute without header
* @skb: socket buffer to add attribute to
* @attrlen: length of attribute payload
@@ -474,6 +551,36 @@ int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
EXPORT_SYMBOL(nla_put);
/**
+ * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr)
+{
+ size_t len;
+
+#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS
+ if (!IS_ALIGNED((unsigned long)skb->data, 8))
+ len = nla_total_size_64bit(attrlen);
+ else
+#endif
+ len = nla_total_size(attrlen);
+
+ if (unlikely(skb_tailroom(skb) < len))
+ return -EMSGSIZE;
+
+ __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
+ return 0;
+}
+EXPORT_SYMBOL(nla_put_64bit);
+
+/**
* nla_put_nohdr - Add a netlink attribute without header
* @skb: socket buffer to add attribute to
* @attrlen: length of attribute payload
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d3694a13c85a..24cd21273383 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1051,14 +1051,9 @@ static noinline_for_stack int rtnl_fill_stats(struct sk_buff *skb,
{
struct rtnl_link_stats64 *sp;
struct nlattr *attr;
- int err;
-
- err = nla_align_64bit(skb, IFLA_PAD);
- if (err)
- return err;
- attr = nla_reserve(skb, IFLA_STATS64,
- sizeof(struct rtnl_link_stats64));
+ attr = nla_reserve_64bit(skb, IFLA_STATS64,
+ sizeof(struct rtnl_link_stats64), IFLA_PAD);
if (!attr)
return -EMSGSIZE;
--
2.4.2
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