From ed8f5b478a3e7017816fd87cbc11a4b91b3da1e6 Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <dborkman@redhat.com>
Date: Tue, 19 Mar 2013 06:39:30 +0000
Subject: [PATCH] --- yaml --- r: 368323 b: refs/heads/master c:
 f77668dc25b27270fe589031b22c432c3462b1d8 h: refs/heads/master i:   368321:
 327c105c4af58c710c6b42d146e991864c826b4a   368319:
 99fe734ea327423df37e04e7ce34bd630354345e v: v3

---
 [refs]                          |  2 +-
 trunk/include/linux/skbuff.h    |  2 ++
 trunk/net/core/flow_dissector.c | 57 +++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index fc64a5248fc4..6a83369acea6 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 61816596d1c9026d0ecb20c44f90452c41596ffe
+refs/heads/master: f77668dc25b27270fe589031b22c432c3462b1d8
diff --git a/trunk/include/linux/skbuff.h b/trunk/include/linux/skbuff.h
index b66ecc6ef102..497412165b1c 100644
--- a/trunk/include/linux/skbuff.h
+++ b/trunk/include/linux/skbuff.h
@@ -2840,6 +2840,8 @@ static inline void skb_checksum_none_assert(const struct sk_buff *skb)
 
 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
 
+u32 __skb_get_poff(const struct sk_buff *skb);
+
 /**
  * skb_head_is_locked - Determine if the skb->head is locked down
  * @skb: skb to check
diff --git a/trunk/net/core/flow_dissector.c b/trunk/net/core/flow_dissector.c
index f4be293bab9e..00ee068efc1c 100644
--- a/trunk/net/core/flow_dissector.c
+++ b/trunk/net/core/flow_dissector.c
@@ -5,6 +5,10 @@
 #include <linux/if_vlan.h>
 #include <net/ip.h>
 #include <net/ipv6.h>
+#include <linux/igmp.h>
+#include <linux/icmp.h>
+#include <linux/sctp.h>
+#include <linux/dccp.h>
 #include <linux/if_tunnel.h>
 #include <linux/if_pppox.h>
 #include <linux/ppp_defs.h>
@@ -228,6 +232,59 @@ u16 __skb_tx_hash(const struct net_device *dev, const 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)
+{
+	struct flow_keys keys;
+	u32 poff = 0;
+
+	if (!skb_flow_dissect(skb, &keys))
+		return 0;
+
+	poff += keys.thoff;
+	switch (keys.ip_proto) {
+	case IPPROTO_TCP: {
+		const struct tcphdr *tcph;
+		struct tcphdr _tcph;
+
+		tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph);
+		if (!tcph)
+			return poff;
+
+		poff += max_t(u32, sizeof(struct tcphdr), tcph->doff * 4);
+		break;
+	}
+	case IPPROTO_UDP:
+	case IPPROTO_UDPLITE:
+		poff += sizeof(struct udphdr);
+		break;
+	/* For the rest, we do not really care about header
+	 * extensions at this point for now.
+	 */
+	case IPPROTO_ICMP:
+		poff += sizeof(struct icmphdr);
+		break;
+	case IPPROTO_ICMPV6:
+		poff += sizeof(struct icmp6hdr);
+		break;
+	case IPPROTO_IGMP:
+		poff += sizeof(struct igmphdr);
+		break;
+	case IPPROTO_DCCP:
+		poff += sizeof(struct dccp_hdr);
+		break;
+	case IPPROTO_SCTP:
+		poff += sizeof(struct sctphdr);
+		break;
+	}
+
+	return poff;
+}
+
 static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
 {
 	if (unlikely(queue_index >= dev->real_num_tx_queues)) {