libnl: add more helpers to align attributes on 64-bit

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 99 insertions, 0 deletions

diff --git a/lib/nlattr.c b/lib/nlattr.c
index f5907d23272d..2b82f1e2ebc2 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -355,6 +355,29 @@ 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)
+{
+	if (nla_need_padding_for_64bit(skb))
+		nla_align_64bit(skb, padattr);
+
+	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 +420,35 @@ 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;
+
+	if (nla_need_padding_for_64bit(skb))
+		len = nla_total_size_64bit(attrlen);
+	else
+		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 +488,26 @@ 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 +546,33 @@ 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;
+
+	if (nla_need_padding_for_64bit(skb))
+		len = nla_total_size_64bit(attrlen);
+	else
+		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