[3.5.y.z extended stable] Patch "net: add and use skb_gso_transport_seglen()" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    net: add and use skb_gso_transport_seglen()

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 063264af7948401c9b600667a6720f9cf593df1a Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw at strlen.de>
Date: Sun, 26 Jan 2014 10:58:16 +0100
Subject: net: add and use skb_gso_transport_seglen()

commit de960aa9ab4decc3304959f69533eef64d05d8e8 upstream.

This moves part of Eric Dumazets skb_gso_seglen helper from tbf sched to
skbuff core so it may be reused by upcoming ip forwarding path patch.

Signed-off-by: Florian Westphal <fw at strlen.de>
Acked-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.5: used davem's backport to 3.4:
  - no skb_gso_seglen helper in 3.4, leave tbf alone ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/linux/skbuff.h |  2 ++
 net/core/skbuff.c      | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 160f3ea..0d40dda 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2171,6 +2171,8 @@ extern int	       skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
 extern struct sk_buff *skb_segment(struct sk_buff *skb,
 				   netdev_features_t features);

+unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
+
 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
 				       int len, void *buffer)
 {
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1e37e1a..50f7c96 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -47,6 +47,8 @@
 #include <linux/in.h>
 #include <linux/inet.h>
 #include <linux/slab.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
 #include <linux/netdevice.h>
 #ifdef CONFIG_NET_CLS_ACT
 #include <net/pkt_sched.h>
@@ -3358,3 +3360,26 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 	return true;
 }
 EXPORT_SYMBOL(skb_try_coalesce);
+
+/**
+ * skb_gso_transport_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_transport_seglen is used to determine the real size of the
+ * individual segments, including Layer4 headers (TCP/UDP).
+ *
+ * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
+ */
+unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
+{
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	unsigned int hdr_len;
+
+	if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
+		hdr_len = tcp_hdrlen(skb);
+	else
+		hdr_len = sizeof(struct udphdr);
+	return hdr_len + shinfo->gso_size;
+}
+EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
--
1.9.0