net: rename skb_gso_validate_mtu -> skb_gso_validate_network_len

If you take a GSO skb, and split it into packets, will the network
length (L3 headers + L4 headers + payload) of those packets be small
enough to fit within a given MTU?

skb_gso_validate_mtu gives you the answer to that question. However,
we recently added to add a way to validate the MAC length of a split GSO
skb (L2+L3+L4+payload), and the names get confusing, so rename
skb_gso_validate_mtu to skb_gso_validate_network_len
Signed-off-by: NDaniel Axtens <dja@axtens.net>
Reviewed-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -3286,7 +3286,7 @@ void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
-bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu);
+bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);

net/core/skbuff.c

@@ -4955,19 +4955,20 @@ static inline bool skb_gso_size_check(const struct sk_buff *skb,
 }
 
 /**
- * skb_gso_validate_mtu - Return in case such skb fits a given MTU
+ * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU?
  *
  * @skb: GSO skb
  * @mtu: MTU to validate against
  *
- * skb_gso_validate_mtu validates if a given skb will fit a wanted MTU
- * once split.
+ * skb_gso_validate_network_len validates if a given skb will fit a
+ * wanted MTU once split. It considers L3 headers, L4 headers, and the
+ * payload.
  */
-bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu)
+bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu)
 {
 	return skb_gso_size_check(skb, skb_gso_network_seglen(skb), mtu);
 }
-EXPORT_SYMBOL_GPL(skb_gso_validate_mtu);
+EXPORT_SYMBOL_GPL(skb_gso_validate_network_len);
 
 /**
  * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?

net/ipv4/ip_forward.c

@@ -55,7 +55,7 @@ static bool ip_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
 	if (skb->ignore_df)
 		return false;
 
-	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 		return false;
 
 	return true;

net/ipv4/ip_output.c

@@ -248,7 +248,7 @@ static int ip_finish_output_gso(struct net *net, struct sock *sk,
 
 	/* common case: seglen is <= mtu
 	 */
-	if (skb_gso_validate_mtu(skb, mtu))
+	if (skb_gso_validate_network_len(skb, mtu))
 		return ip_finish_output2(net, sk, skb);
 
 	/* Slowpath -  GSO segment length exceeds the egress MTU.

net/ipv4/netfilter/nf_flow_table_ipv4.c

@@ -186,7 +186,7 @@ static bool __nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
 	if ((ip_hdr(skb)->frag_off & htons(IP_DF)) == 0)
 		return false;
 
-	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 		return false;
 
 	return true;

net/ipv6/ip6_output.c

@@ -412,7 +412,7 @@ static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 	if (skb->ignore_df)
 		return false;
 
-	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 		return false;
 
 	return true;

net/ipv6/netfilter/nf_flow_table_ipv6.c

@@ -178,7 +178,7 @@ static bool __nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
 	if (skb->len <= mtu)
 		return false;
 
-	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 		return false;
 
 	return true;

net/mpls/af_mpls.c

@@ -122,7 +122,7 @@ bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 	if (skb->len <= mtu)
 		return false;
 
-	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 		return false;
 
 	return true;

net/xfrm/xfrm_device.c

@@ -217,7 +217,7 @@ bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 		if (skb->len <= mtu)
 			goto ok;
 
-		if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
+		if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 			goto ok;
 	}