net: adopt skb_network_header_len() more broadly

(skb_transport_header(skb) - skb_network_header(skb))
can be replaced by skb_network_header_len(skb)

Add a DEBUG_NET_WARN_ON_ONCE() in skb_network_header_len()
to catch cases were the transport_header was not set.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -3621,8 +3621,7 @@ static u8 bnx2x_set_pbd_csum(struct bnx2x *bp, struct sk_buff *skb,
 			    ((skb->protocol == cpu_to_be16(ETH_P_8021Q)) <<
 			     ETH_TX_PARSE_BD_E1X_LLC_SNAP_EN_SHIFT));
 
-	pbd->ip_hlen_w = (skb_transport_header(skb) -
-			skb_network_header(skb)) >> 1;
+	pbd->ip_hlen_w = skb_network_header_len(skb) >> 1;
 
 	hlen += pbd->ip_hlen_w;
 

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -13213,7 +13213,7 @@ static netdev_features_t i40e_features_check(struct sk_buff *skb,
 		goto out_err;
 
 	/* IPLEN and EIPLEN can support at most 127 dwords */
-	len = skb_transport_header(skb) - skb_network_header(skb);
+	len = skb_network_header_len(skb);
 	if (len & ~(127 * 4))
 		goto out_err;
 

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -4428,7 +4428,7 @@ static netdev_features_t iavf_features_check(struct sk_buff *skb,
 		goto out_err;
 
 	/* IPLEN and EIPLEN can support at most 127 dwords */
-	len = skb_transport_header(skb) - skb_network_header(skb);
+	len = skb_network_header_len(skb);
 	if (len & ~(127 * 4))
 		goto out_err;
 

drivers/net/wireless/intel/iwlwifi/mvm/tx.c

@@ -1015,8 +1015,7 @@ static int iwl_mvm_tx_tso(struct iwl_mvm *mvm, struct sk_buff *skb,
 	netdev_features_t netdev_flags = NETIF_F_CSUM_MASK | NETIF_F_SG;
 	u8 tid;
 
-	snap_ip_tcp = 8 + skb_transport_header(skb) - skb_network_header(skb) +
-		tcp_hdrlen(skb);
+	snap_ip_tcp = 8 + skb_network_header_len(skb) + tcp_hdrlen(skb);
 
 	if (!mvmsta->max_amsdu_len ||
 	    !ieee80211_is_data_qos(hdr->frame_control) ||

drivers/net/wireless/intel/iwlwifi/pcie/tx.c

@@ -1331,7 +1331,7 @@ static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
 			     trans->txqs.tfd.size,
 			     &dev_cmd->hdr, IWL_FIRST_TB_SIZE + tb1_len, 0);
 
-	ip_hdrlen = skb_transport_header(skb) - skb_network_header(skb);
+	ip_hdrlen = skb_network_header_len(skb);
 	snap_ip_tcp_hdrlen = 8 + ip_hdrlen + tcp_hdrlen(skb);
 	total_len = skb->len - snap_ip_tcp_hdrlen - hdr_len - iv_len;
 	amsdu_pad = 0;

drivers/net/wireless/intel/iwlwifi/queue/tx.c

@@ -353,7 +353,7 @@ static int iwl_txq_gen2_build_amsdu(struct iwl_trans *trans,
 	trace_iwlwifi_dev_tx(trans->dev, skb, tfd, sizeof(*tfd),
 			     &dev_cmd->hdr, start_len, 0);
 
-	ip_hdrlen = skb_transport_header(skb) - skb_network_header(skb);
+	ip_hdrlen = skb_network_header_len(skb);
 	snap_ip_tcp_hdrlen = 8 + ip_hdrlen + tcp_hdrlen(skb);
 	total_len = skb->len - snap_ip_tcp_hdrlen - hdr_len;
 	amsdu_pad = 0;

include/linux/skbuff.h

@@ -3036,6 +3036,7 @@ static inline int skb_transport_offset(const struct sk_buff *skb)
 
 static inline u32 skb_network_header_len(const struct sk_buff *skb)
 {
+	DEBUG_NET_WARN_ON_ONCE(!skb_transport_header_was_set(skb));
 	return skb->transport_header - skb->network_header;
 }