skbuff: introduce skb_gso_validate_mtu
skb_gso_network_seglen is not enough for checking fragment sizes if
skb is using GSO_BY_FRAGS as we have to check frag per frag.
This patch introduces skb_gso_validate_mtu, based on the former, which
will wrap the use case inside it as all calls to skb_gso_network_seglen
were to validate if it fits on a given TMU, and improve the check.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 97c32c7..5ca562b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4392,6 +4392,37 @@
}
EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
+/**
+ * skb_gso_validate_mtu - Return in case such skb fits a given MTU
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_validate_mtu validates if a given skb will fit a wanted MTU
+ * once split.
+ */
+bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu)
+{
+ const struct skb_shared_info *shinfo = skb_shinfo(skb);
+ const struct sk_buff *iter;
+ unsigned int hlen;
+
+ hlen = skb_gso_network_seglen(skb);
+
+ if (shinfo->gso_size != GSO_BY_FRAGS)
+ return hlen <= mtu;
+
+ /* Undo this so we can re-use header sizes */
+ hlen -= GSO_BY_FRAGS;
+
+ skb_walk_frags(skb, iter) {
+ if (hlen + skb_headlen(iter) > mtu)
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(skb_gso_validate_mtu);
+
static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
{
if (skb_cow(skb, skb_headroom(skb)) < 0) {