4 files changed, 108 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 08074a810164..3ca0dda5a42e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2741,6 +2741,99 @@ static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
 	       0 : __skb_checksum_complete(skb);
 }
 
+/* Check if we need to perform checksum complete validation.
+ *
+ * Returns true if checksum complete is needed, false otherwise
+ * (either checksum is unnecessary or zero checksum is allowed).
+ */
+static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
+						  bool zero_okay,
+						  __sum16 check)
+{
+	if (skb_csum_unnecessary(skb)) {
+		return false;
+	} else if (zero_okay && !check) {
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		return false;
+	}
+
+	return true;
+}
+
+/* For small packets <= CHECKSUM_BREAK peform checksum complete directly
+ * in checksum_init.
+ */
+#define CHECKSUM_BREAK 76
+
+/* Validate (init) checksum based on checksum complete.
+ *
+ * Return values:
+ *   0: checksum is validated or try to in skb_checksum_complete. In the latter
+ *	case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
+ *	checksum is stored in skb->csum for use in __skb_checksum_complete
+ *   non-zero: value of invalid checksum
+ *
+ */
+static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
+						       bool complete,
+						       __wsum psum)
+{
+	if (skb->ip_summed == CHECKSUM_COMPLETE) {
+		if (!csum_fold(csum_add(psum, skb->csum))) {
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+			return 0;
+		}
+	}
+
+	skb->csum = psum;
+
+	if (complete || skb->len <= CHECKSUM_BREAK)
+		return __skb_checksum_complete(skb);
+
+	return 0;
+}
+
+static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
+{
+	return 0;
+}
+
+/* Perform checksum validate (init). Note that this is a macro since we only
+ * want to calculate the pseudo header which is an input function if necessary.
+ * First we try to validate without any computation (checksum unnecessary) and
+ * then calculate based on checksum complete calling the function to compute
+ * pseudo header.
+ *
+ * Return values:
+ *   0: checksum is validated or try to in skb_checksum_complete
+ *   non-zero: value of invalid checksum
+ */
+#define __skb_checksum_validate(skb, proto, complete,			\
+				zero_okay, check, compute_pseudo)	\
+({									\
+	__sum16 __ret = 0;						\
+	if (__skb_checksum_validate_needed(skb, zero_okay, check))	\
+		__ret = __skb_checksum_validate_complete(skb,		\
+				complete, compute_pseudo(skb, proto));	\
+	__ret;								\
+})
+
+#define skb_checksum_init(skb, proto, compute_pseudo)			\
+	__skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
+
+#define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo)	\
+	__skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
+
+#define skb_checksum_validate(skb, proto, compute_pseudo)		\
+	__skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
+
+#define skb_checksum_validate_zero_check(skb, proto, check,		\
+					 compute_pseudo)		\
+	__skb_checksum_validate_(skb, proto, true, true, check, compute_pseudo)
+
+#define skb_checksum_simple_validate(skb)				\
+	__skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
+
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 void nf_conntrack_destroy(struct nf_conntrack *nfct);
 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
diff --git a/include/net/checksum.h b/include/net/checksum.h
index a28f4e0f6251..87cb1903640d 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -57,12 +57,14 @@ static __inline__ __wsum csum_and_copy_to_user
 }
 #endif
 
+#ifndef HAVE_ARCH_CSUM_ADD
 static inline __wsum csum_add(__wsum csum, __wsum addend)
 {
 	u32 res = (__force u32)csum;
 	res += (__force u32)addend;
 	return (__force __wsum)(res + (res < (__force u32)addend));
 }
+#endif
 
 static inline __wsum csum_sub(__wsum csum, __wsum addend)
 {
diff --git a/include/net/ip.h b/include/net/ip.h
index 3ec2b0fb9d83..1988cefdbb70 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -342,6 +342,12 @@ static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *d
 		__ip_select_ident(iph, dst, more);
 }
 
+static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
+{
+	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
+				  skb->len, proto, 0);
+}
+
 /*
  *	Map a multicast IP onto multicast MAC for type ethernet.
  */
diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index 9e3c540c1b11..8ac5c21f8456 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -41,6 +41,13 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 			__wsum csum);
 #endif
 
+static inline __wsum ip6_compute_pseudo(struct sk_buff *skb, int proto)
+{
+	return ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+					    &ipv6_hdr(skb)->daddr,
+					    skb->len, proto, 0));
+}
+
 static __inline__ __sum16 tcp_v6_check(int len,
 				   const struct in6_addr *saddr,
 				   const struct in6_addr *daddr,