Merge branch 'eth_get_headlen'

Alexander Duyck says:

====================
net: Drop get_headlen functions in favor of generic function

This series replaces the igb_get_headlen and ixgbe_get_headlen functions
with a generic function named eth_get_headlen.

I have done some performance testing on ixgbe with 258 byte frames since
the calls are only used on frames larger than 256 bytes and have seen no
significant difference in CPU utilization.

v2: renamed __skb_get_poff to skb_get_poff
    renamed ___skb_get_poff to __skb_get_poff
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 60 insertions, 15 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 37f8eb06fdee..fa5b7d0f77ac 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -113,7 +113,7 @@ static unsigned int pkt_type_offset(void)
 
 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
 {
-	return __skb_get_poff((struct sk_buff *)(unsigned long) ctx);
+	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
 }
 
 static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 12f48ca7a0b0..8560dea58803 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -13,6 +13,7 @@
 #include <linux/if_pppox.h>
 #include <linux/ppp_defs.h>
 #include <net/flow_keys.h>
+#include <scsi/fc/fc_fcoe.h>
 
 /* copy saddr & daddr, possibly using 64bit load/store
  * Equivalent to :	flow->src = iph->saddr;
@@ -117,6 +118,13 @@ ipv6:
 		flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
 		nhoff += sizeof(struct ipv6hdr);
 
+		/* skip the flow label processing if skb is NULL.  The
+		 * assumption here is that if there is no skb we are not
+		 * looking for flow info as much as we are length.
+		 */
+		if (!skb)
+			break;
+
 		flow_label = ip6_flowlabel(iph);
 		if (flow_label) {
 			/* Awesome, IPv6 packet has a flow label so we can
@@ -165,6 +173,9 @@ ipv6:
 			return false;
 		}
 	}
+	case htons(ETH_P_FCOE):
+		flow->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
+		/* fall through */
 	default:
 		return false;
 	}
@@ -316,26 +327,18 @@ u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(__skb_tx_hash);
 
-/* __skb_get_poff() returns the offset to the payload as far as it could
- * be dissected. The main user is currently BPF, so that we can dynamically
- * truncate packets without needing to push actual payload to the user
- * space and can analyze headers only, instead.
- */
-u32 __skb_get_poff(const struct sk_buff *skb)
+u32 __skb_get_poff(const struct sk_buff *skb, void *data,
+		   const struct flow_keys *keys, int hlen)
 {
-	struct flow_keys keys;
-	u32 poff = 0;
+	u32 poff = keys->thoff;
 
-	if (!skb_flow_dissect(skb, &keys))
-		return 0;
-
-	poff += keys.thoff;
-	switch (keys.ip_proto) {
+	switch (keys->ip_proto) {
 	case IPPROTO_TCP: {
 		const struct tcphdr *tcph;
 		struct tcphdr _tcph;
 
-		tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph);
+		tcph = __skb_header_pointer(skb, poff, sizeof(_tcph),
+					    data, hlen, &_tcph);
 		if (!tcph)
 			return poff;
 
@@ -369,6 +372,21 @@ u32 __skb_get_poff(const struct sk_buff *skb)
 	return poff;
 }
 
+/* skb_get_poff() returns the offset to the payload as far as it could
+ * be dissected. The main user is currently BPF, so that we can dynamically
+ * truncate packets without needing to push actual payload to the user
+ * space and can analyze headers only, instead.
+ */
+u32 skb_get_poff(const struct sk_buff *skb)
+{
+	struct flow_keys keys;
+
+	if (!skb_flow_dissect(skb, &keys))
+		return 0;
+
+	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
+}
+
 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
 {
 #ifdef CONFIG_XPS
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 5cebca134585..33a140e15834 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -146,6 +146,33 @@ int eth_rebuild_header(struct sk_buff *skb)
 EXPORT_SYMBOL(eth_rebuild_header);
 
 /**
+ * eth_get_headlen - determine the the length of header for an ethernet frame
+ * @data: pointer to start of frame
+ * @len: total length of frame
+ *
+ * Make a best effort attempt to pull the length for all of the headers for
+ * a given frame in a linear buffer.
+ */
+u32 eth_get_headlen(void *data, unsigned int len)
+{
+	const struct ethhdr *eth = (const struct ethhdr *)data;
+	struct flow_keys keys;
+
+	/* this should never happen, but better safe than sorry */
+	if (len < sizeof(*eth))
+		return len;
+
+	/* parse any remaining L2/L3 headers, check for L4 */
+	if (!__skb_flow_dissect(NULL, &keys, data,
+				eth->h_proto, sizeof(*eth), len))
+		return max_t(u32, keys.thoff, sizeof(*eth));
+
+	/* parse for any L4 headers */
+	return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
+}
+EXPORT_SYMBOL(eth_get_headlen);
+
+/**
  * eth_type_trans - determine the packet's protocol ID.
  * @skb: received socket data
  * @dev: receiving network device