Merge branch 'sctp_csum'

Daniel Borkmann says:

====================
SCTP fix/updates

Please see patch 5 for the main description/motivation, the rest just
brings in the needed functionality for that. Although this is actually
a fix, I've based it against net-next as some additional work for
fixing it was needed.
====================

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 350 insertions, 258 deletions

diff --git a/include/linux/crc32.h b/include/linux/crc32.h
index 68267b64bb98..7d275c4fc011 100644
--- a/include/linux/crc32.h
+++ b/include/linux/crc32.h
@@ -11,8 +11,48 @@
 extern u32  crc32_le(u32 crc, unsigned char const *p, size_t len);
 extern u32  crc32_be(u32 crc, unsigned char const *p, size_t len);
 
+/**
+ * crc32_le_combine - Combine two crc32 check values into one. For two
+ * 		      sequences of bytes, seq1 and seq2 with lengths len1
+ * 		      and len2, crc32_le() check values were calculated
+ * 		      for each, crc1 and crc2.
+ *
+ * @crc1: crc32 of the first block
+ * @crc2: crc32 of the second block
+ * @len2: length of the second block
+ *
+ * Return: The crc32_le() check value of seq1 and seq2 concatenated,
+ * 	   requiring only crc1, crc2, and len2. Note: If seq_full denotes
+ * 	   the concatenated memory area of seq1 with seq2, and crc_full
+ * 	   the crc32_le() value of seq_full, then crc_full ==
+ * 	   crc32_le_combine(crc1, crc2, len2) when crc_full was seeded
+ * 	   with the same initializer as crc1, and crc2 seed was 0. See
+ * 	   also crc32_combine_test().
+ */
+extern u32  crc32_le_combine(u32 crc1, u32 crc2, size_t len2);
+
 extern u32  __crc32c_le(u32 crc, unsigned char const *p, size_t len);
 
+/**
+ * __crc32c_le_combine - Combine two crc32c check values into one. For two
+ * 			 sequences of bytes, seq1 and seq2 with lengths len1
+ * 			 and len2, __crc32c_le() check values were calculated
+ * 			 for each, crc1 and crc2.
+ *
+ * @crc1: crc32c of the first block
+ * @crc2: crc32c of the second block
+ * @len2: length of the second block
+ *
+ * Return: The __crc32c_le() check value of seq1 and seq2 concatenated,
+ * 	   requiring only crc1, crc2, and len2. Note: If seq_full denotes
+ * 	   the concatenated memory area of seq1 with seq2, and crc_full
+ * 	   the __crc32c_le() value of seq_full, then crc_full ==
+ * 	   __crc32c_le_combine(crc1, crc2, len2) when crc_full was
+ * 	   seeded with the same initializer as crc1, and crc2 seed
+ * 	   was 0. See also crc32c_combine_test().
+ */
+extern u32  __crc32c_le_combine(u32 crc1, u32 crc2, size_t len2);
+
 #define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)(data), length)
 
 /*
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2c154976394b..44727b5d4981 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2360,8 +2360,6 @@ int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset,
 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
 void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
-__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
-		    __wsum csum);
 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
@@ -2373,9 +2371,18 @@ void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
-
 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
 
+struct skb_checksum_ops {
+	__wsum (*update)(const void *mem, int len, __wsum wsum);
+	__wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
+};
+
+__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
+		      __wsum csum, const struct skb_checksum_ops *ops);
+__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
+		    __wsum csum);
+
 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
 				       int len, void *buffer)
 {
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 8f59ca50477c..15f33fde826e 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -79,6 +79,12 @@ csum_block_add(__wsum csum, __wsum csum2, int offset)
 }
 
 static inline __wsum
+csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
+{
+	return csum_block_add(csum, csum2, offset);
+}
+
+static inline __wsum
 csum_block_sub(__wsum csum, __wsum csum2, int offset)
 {
 	u32 sum = (__force u32)csum2;
diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index 259924d63ba6..6bd44fe94c26 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -42,56 +42,38 @@
 #include <linux/types.h>
 #include <net/sctp/sctp.h>
 #include <linux/crc32c.h>
+#include <linux/crc32.h>
 
-static inline __u32 sctp_crc32c(__u32 crc, u8 *buffer, u16 length)
+static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
 {
-	return crc32c(crc, buffer, length);
-}
-
-static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
-{
-	__u32 crc = ~(__u32)0;
-	__u8  zero[sizeof(__u32)] = {0};
-
-	/* Optimize this routine to be SCTP specific, knowing how
-	 * to skip the checksum field of the SCTP header.
+	/* This uses the crypto implementation of crc32c, which is either
+	 * implemented w/ hardware support or resolves to __crc32c_le().
 	 */
-
-	/* Calculate CRC up to the checksum. */
-	crc = sctp_crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32));
-
-	/* Skip checksum field of the header. */
-	crc = sctp_crc32c(crc, zero, sizeof(__u32));
-
-	/* Calculate the rest of the CRC. */
-	crc = sctp_crc32c(crc, &buffer[sizeof(struct sctphdr)],
-			    length - sizeof(struct sctphdr));
-	return crc;
-}
-
-static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
-{
-	return sctp_crc32c(crc32, buffer, length);
+	return crc32c(sum, buff, len);
 }
 
-static inline __le32 sctp_end_cksum(__u32 crc32)
+static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
+				       int offset, int len)
 {
-	return cpu_to_le32(~crc32);
+	return __crc32c_le_combine(csum, csum2, len);
 }
 
-/* Calculate the CRC32C checksum of an SCTP packet.  */
 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
 					unsigned int offset)
 {
-	const struct sk_buff *iter;
+	struct sctphdr *sh = sctp_hdr(skb);
+        __le32 ret, old = sh->checksum;
+	const struct skb_checksum_ops ops = {
+		.update  = sctp_csum_update,
+		.combine = sctp_csum_combine,
+	};
 
-	__u32 crc32 = sctp_start_cksum(skb->data + offset,
-				       skb_headlen(skb) - offset);
-	skb_walk_frags(skb, iter)
-		crc32 = sctp_update_cksum((__u8 *) iter->data,
-					  skb_headlen(iter), crc32);
+	sh->checksum = 0;
+	ret = cpu_to_le32(~__skb_checksum(skb, offset, skb->len - offset,
+					  ~(__u32)0, &ops));
+	sh->checksum = old;
 
-	return sctp_end_cksum(crc32);
+	return ret;
 }
 
 #endif /* __sctp_checksum_h__ */
diff --git a/lib/crc32.c b/lib/crc32.c
index 410093dbe51c..69dd124f0cfc 100644
--- a/lib/crc32.c
+++ b/lib/crc32.c
@@ -49,6 +49,30 @@ MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>");
 MODULE_DESCRIPTION("Various CRC32 calculations");
 MODULE_LICENSE("GPL");
 
+#define GF2_DIM		32
+
+static u32 gf2_matrix_times(u32 *mat, u32 vec)
+{
+	u32 sum = 0;
+
+	while (vec) {
+		if (vec & 1)
+			sum ^= *mat;
+		vec >>= 1;
+		mat++;
+	}
+
+	return sum;
+}
+
+static void gf2_matrix_square(u32 *square, u32 *mat)
+{
+	int i;
+
+	for (i = 0; i < GF2_DIM; i++)
+		square[i] = gf2_matrix_times(mat, mat[i]);
+}
+
 #if CRC_LE_BITS > 8 || CRC_BE_BITS > 8
 
 /* implements slicing-by-4 or slicing-by-8 algorithm */
@@ -130,6 +154,52 @@ crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256])
 }
 #endif
 
+/* For conditions of distribution and use, see copyright notice in zlib.h */
+static u32 crc32_generic_combine(u32 crc1, u32 crc2, size_t len2,
+				 u32 polynomial)
+{
+	u32 even[GF2_DIM]; /* Even-power-of-two zeros operator */
+	u32 odd[GF2_DIM];  /* Odd-power-of-two zeros operator  */
+	u32 row;
+	int i;
+
+	if (len2 <= 0)
+		return crc1;
+
+	/* Put operator for one zero bit in odd */
+	odd[0] = polynomial;
+	row = 1;
+	for (i = 1; i < GF2_DIM; i++) {
+		odd[i] = row;
+		row <<= 1;
+	}
+
+	gf2_matrix_square(even, odd); /* Put operator for two zero bits in even */
+	gf2_matrix_square(odd, even); /* Put operator for four zero bits in odd */
+
+	/* Apply len2 zeros to crc1 (first square will put the operator for one
+	 * zero byte, eight zero bits, in even).
+	 */
+	do {
+		/* Apply zeros operator for this bit of len2 */
+		gf2_matrix_square(even, odd);
+		if (len2 & 1)
+			crc1 = gf2_matrix_times(even, crc1);
+		len2 >>= 1;
+		/* If no more bits set, then done */
+		if (len2 == 0)
+			break;
+		/* Another iteration of the loop with odd and even swapped */
+		gf2_matrix_square(odd, even);
+		if (len2 & 1)
+			crc1 = gf2_matrix_times(odd, crc1);
+		len2 >>= 1;
+	} while (len2 != 0);
+
+	crc1 ^= crc2;
+	return crc1;
+}
+
 /**
  * crc32_le_generic() - Calculate bitwise little-endian Ethernet AUTODIN II
  *			CRC32/CRC32C
@@ -200,8 +270,19 @@ u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len)
 			(const u32 (*)[256])crc32ctable_le, CRC32C_POLY_LE);
 }
 #endif
+u32 __pure crc32_le_combine(u32 crc1, u32 crc2, size_t len2)
+{
+	return crc32_generic_combine(crc1, crc2, len2, CRCPOLY_LE);
+}
+
+u32 __pure __crc32c_le_combine(u32 crc1, u32 crc2, size_t len2)
+{
+	return crc32_generic_combine(crc1, crc2, len2, CRC32C_POLY_LE);
+}
 EXPORT_SYMBOL(crc32_le);
+EXPORT_SYMBOL(crc32_le_combine);
 EXPORT_SYMBOL(__crc32c_le);
+EXPORT_SYMBOL(__crc32c_le_combine);
 
 /**
  * crc32_be_generic() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
@@ -795,206 +876,106 @@ static struct crc_test {
 	u32 crc32c_le;	/* expected crc32c_le result */
 } test[] =
 {
-	{0x674bf11d, 0x00000038, 0x00000542, 0x0af6d466, 0xd8b6e4c1,
-	 0xf6e93d6c},
-	{0x35c672c6, 0x0000003a, 0x000001aa, 0xc6d3dfba, 0x28aaf3ad,
-	 0x0fe92aca},
-	{0x496da28e, 0x00000039, 0x000005af, 0xd933660f, 0x5d57e81f,
-	 0x52e1ebb8},
-	{0x09a9b90e, 0x00000027, 0x000001f8, 0xb45fe007, 0xf45fca9a,
-	 0x0798af9a},
-	{0xdc97e5a9, 0x00000025, 0x000003b6, 0xf81a3562, 0xe0126ba2,
-	 0x18eb3152},
-	{0x47c58900, 0x0000000a, 0x000000b9, 0x8e58eccf, 0xf3afc793,
-	 0xd00d08c7},
-	{0x292561e8, 0x0000000c, 0x00000403, 0xa2ba8aaf, 0x0b797aed,
-	 0x8ba966bc},
-	{0x415037f6, 0x00000003, 0x00000676, 0xa17d52e8, 0x7f0fdf35,
-	 0x11d694a2},
-	{0x3466e707, 0x00000026, 0x00000042, 0x258319be, 0x75c484a2,
-	 0x6ab3208d},
-	{0xafd1281b, 0x00000023, 0x000002ee, 0x4428eaf8, 0x06c7ad10,
-	 0xba4603c5},
-	{0xd3857b18, 0x00000028, 0x000004a2, 0x5c430821, 0xb062b7cb,
-	 0xe6071c6f},
-	{0x1d825a8f, 0x0000002b, 0x0000050b, 0xd2c45f0c, 0xd68634e0,
-	 0x179ec30a},
-	{0x5033e3bc, 0x0000000b, 0x00000078, 0xa3ea4113, 0xac6d31fb,
-	 0x0903beb8},
-	{0x94f1fb5e, 0x0000000f, 0x000003a2, 0xfbfc50b1, 0x3cfe50ed,
-	 0x6a7cb4fa},
-	{0xc9a0fe14, 0x00000009, 0x00000473, 0x5fb61894, 0x87070591,
-	 0xdb535801},
-	{0x88a034b1, 0x0000001c, 0x000005ad, 0xc1b16053, 0x46f95c67,
-	 0x92bed597},
-	{0xf0f72239, 0x00000020, 0x0000026d, 0xa6fa58f3, 0xf8c2c1dd,
-	 0x192a3f1b},
-	{0xcc20a5e3, 0x0000003b, 0x0000067a, 0x7740185a, 0x308b979a,
-	 0xccbaec1a},
-	{0xce589c95, 0x0000002b, 0x00000641, 0xd055e987, 0x40aae25b,
-	 0x7eabae4d},
-	{0x78edc885, 0x00000035, 0x000005be, 0xa39cb14b, 0x035b0d1f,
-	 0x28c72982},
-	{0x9d40a377, 0x0000003b, 0x00000038, 0x1f47ccd2, 0x197fbc9d,
-	 0xc3cd4d18},
-	{0x703d0e01, 0x0000003c, 0x000006f1, 0x88735e7c, 0xfed57c5a,
-	 0xbca8f0e7},
-	{0x776bf505, 0x0000000f, 0x000005b2, 0x5cc4fc01, 0xf32efb97,
-	 0x713f60b3},
-	{0x4a3e7854, 0x00000027, 0x000004b8, 0x8d923c82, 0x0cbfb4a2,
-	 0xebd08fd5},
-	{0x209172dd, 0x0000003b, 0x00000356, 0xb89e9c2b, 0xd7868138,
-	 0x64406c59},
-	{0x3ba4cc5b, 0x0000002f, 0x00000203, 0xe51601a9, 0x5b2a1032,
-	 0x7421890e},
-	{0xfc62f297, 0x00000000, 0x00000079, 0x71a8e1a2, 0x5d88685f,
-	 0xe9347603},
-	{0x64280b8b, 0x00000016, 0x000007ab, 0x0fa7a30c, 0xda3a455f,
-	 0x1bef9060},
-	{0x97dd724b, 0x00000033, 0x000007ad, 0x5788b2f4, 0xd7326d32,
-	 0x34720072},
-	{0x61394b52, 0x00000035, 0x00000571, 0xc66525f1, 0xcabe7fef,
-	 0x48310f59},
-	{0x29b4faff, 0x00000024, 0x0000006e, 0xca13751e, 0x993648e0,
-	 0x783a4213},
-	{0x29bfb1dc, 0x0000000b, 0x00000244, 0x436c43f7, 0x429f7a59,
-	 0x9e8efd41},
-	{0x86ae934b, 0x00000035, 0x00000104, 0x0760ec93, 0x9cf7d0f4,
-	 0xfc3d34a5},
-	{0xc4c1024e, 0x0000002e, 0x000006b1, 0x6516a3ec, 0x19321f9c,
-	 0x17a52ae2},
-	{0x3287a80a, 0x00000026, 0x00000496, 0x0b257eb1, 0x754ebd51,
-	 0x886d935a},
-	{0xa4db423e, 0x00000023, 0x0000045d, 0x9b3a66dc, 0x873e9f11,
-	 0xeaaeaeb2},
-	{0x7a1078df, 0x00000015, 0x0000014a, 0x8c2484c5, 0x6a628659,
-	 0x8e900a4b},
-	{0x6048bd5b, 0x00000006, 0x0000006a, 0x897e3559, 0xac9961af,
-	 0xd74662b1},
-	{0xd8f9ea20, 0x0000003d, 0x00000277, 0x60eb905b, 0xed2aaf99,
-	 0xd26752ba},
-	{0xea5ec3b4, 0x0000002a, 0x000004fe, 0x869965dc, 0x6c1f833b,
-	 0x8b1fcd62},
-	{0x2dfb005d, 0x00000016, 0x00000345, 0x6a3b117e, 0xf05e8521,
-	 0xf54342fe},
-	{0x5a214ade, 0x00000020, 0x000005b6, 0x467f70be, 0xcb22ccd3,
-	 0x5b95b988},
-	{0xf0ab9cca, 0x00000032, 0x00000515, 0xed223df3, 0x7f3ef01d,
-	 0x2e1176be},
-	{0x91b444f9, 0x0000002e, 0x000007f8, 0x84e9a983, 0x5676756f,
-	 0x66120546},
-	{0x1b5d2ddb, 0x0000002e, 0x0000012c, 0xba638c4c, 0x3f42047b,
-	 0xf256a5cc},
-	{0xd824d1bb, 0x0000003a, 0x000007b5, 0x6288653b, 0x3a3ebea0,
-	 0x4af1dd69},
-	{0x0470180c, 0x00000034, 0x000001f0, 0x9d5b80d6, 0x3de08195,
-	 0x56f0a04a},
-	{0xffaa3a3f, 0x00000036, 0x00000299, 0xf3a82ab8, 0x53e0c13d,
-	 0x74f6b6b2},
-	{0x6406cfeb, 0x00000023, 0x00000600, 0xa920b8e8, 0xe4e2acf4,
-	 0x085951fd},
-	{0xb24aaa38, 0x0000003e, 0x000004a1, 0x657cc328, 0x5077b2c3,
-	 0xc65387eb},
-	{0x58b2ab7c, 0x00000039, 0x000002b4, 0x3a17ee7e, 0x9dcb3643,
-	 0x1ca9257b},
-	{0x3db85970, 0x00000006, 0x000002b6, 0x95268b59, 0xb9812c10,
-	 0xfd196d76},
-	{0x857830c5, 0x00000003, 0x00000590, 0x4ef439d5, 0xf042161d,
-	 0x5ef88339},
-	{0xe1fcd978, 0x0000003e, 0x000007d8, 0xae8d8699, 0xce0a1ef5,
-	 0x2c3714d9},
-	{0xb982a768, 0x00000016, 0x000006e0, 0x62fad3df, 0x5f8a067b,
-	 0x58576548},
-	{0x1d581ce8, 0x0000001e, 0x0000058b, 0xf0f5da53, 0x26e39eee,
-	 0xfd7c57de},
-	{0x2456719b, 0x00000025, 0x00000503, 0x4296ac64, 0xd50e4c14,
-	 0xd5fedd59},
-	{0xfae6d8f2, 0x00000000, 0x0000055d, 0x057fdf2e, 0x2a31391a,
-	 0x1cc3b17b},
-	{0xcba828e3, 0x00000039, 0x000002ce, 0xe3f22351, 0x8f00877b,
-	 0x270eed73},
-	{0x13d25952, 0x0000000a, 0x0000072d, 0x76d4b4cc, 0x5eb67ec3,
-	 0x91ecbb11},
-	{0x0342be3f, 0x00000015, 0x00000599, 0xec75d9f1, 0x9d4d2826,
-	 0x05ed8d0c},
-	{0xeaa344e0, 0x00000014, 0x000004d8, 0x72a4c981, 0x2064ea06,
-	 0x0b09ad5b},
-	{0xbbb52021, 0x0000003b, 0x00000272, 0x04af99fc, 0xaf042d35,
-	 0xf8d511fb},
-	{0xb66384dc, 0x0000001d, 0x000007fc, 0xd7629116, 0x782bd801,
-	 0x5ad832cc},
-	{0x616c01b6, 0x00000022, 0x000002c8, 0x5b1dab30, 0x783ce7d2,
-	 0x1214d196},
-	{0xce2bdaad, 0x00000016, 0x0000062a, 0x932535c8, 0x3f02926d,
-	 0x5747218a},
-	{0x00fe84d7, 0x00000005, 0x00000205, 0x850e50aa, 0x753d649c,
-	 0xde8f14de},
-	{0xbebdcb4c, 0x00000006, 0x0000055d, 0xbeaa37a2, 0x2d8c9eba,
-	 0x3563b7b9},
-	{0xd8b1a02a, 0x00000010, 0x00000387, 0x5017d2fc, 0x503541a5,
-	 0x071475d0},
-	{0x3b96cad2, 0x00000036, 0x00000347, 0x1d2372ae, 0x926cd90b,
-	 0x54c79d60},
-	{0xc94c1ed7, 0x00000005, 0x0000038b, 0x9e9fdb22, 0x144a9178,
-	 0x4c53eee6},
-	{0x1aad454e, 0x00000025, 0x000002b2, 0xc3f6315c, 0x5c7a35b3,
-	 0x10137a3c},
-	{0xa4fec9a6, 0x00000000, 0x000006d6, 0x90be5080, 0xa4107605,
-	 0xaa9d6c73},
-	{0x1bbe71e2, 0x0000001f, 0x000002fd, 0x4e504c3b, 0x284ccaf1,
-	 0xb63d23e7},
-	{0x4201c7e4, 0x00000002, 0x000002b7, 0x7822e3f9, 0x0cc912a9,
-	 0x7f53e9cf},
-	{0x23fddc96, 0x00000003, 0x00000627, 0x8a385125, 0x07767e78,
-	 0x13c1cd83},
-	{0xd82ba25c, 0x00000016, 0x0000063e, 0x98e4148a, 0x283330c9,
-	 0x49ff5867},
-	{0x786f2032, 0x0000002d, 0x0000060f, 0xf201600a, 0xf561bfcd,
-	 0x8467f211},
-	{0xfebe4e1f, 0x0000002a, 0x000004f2, 0x95e51961, 0xfd80dcab,
-	 0x3f9683b2},
-	{0x1a6e0a39, 0x00000008, 0x00000672, 0x8af6c2a5, 0x78dd84cb,
-	 0x76a3f874},
-	{0x56000ab8, 0x0000000e, 0x000000e5, 0x36bacb8f, 0x22ee1f77,
-	 0x863b702f},
-	{0x4717fe0c, 0x00000000, 0x000006ec, 0x8439f342, 0x5c8e03da,
-	 0xdc6c58ff},
-	{0xd5d5d68e, 0x0000003c, 0x000003a3, 0x46fff083, 0x177d1b39,
-	 0x0622cc95},
-	{0xc25dd6c6, 0x00000024, 0x000006c0, 0x5ceb8eb4, 0x892b0d16,
-	 0xe85605cd},
-	{0xe9b11300, 0x00000023, 0x00000683, 0x07a5d59a, 0x6c6a3208,
-	 0x31da5f06},
-	{0x95cd285e, 0x00000001, 0x00000047, 0x7b3a4368, 0x0202c07e,
-	 0xa1f2e784},
-	{0xd9245a25, 0x0000001e, 0x000003a6, 0xd33c1841, 0x1936c0d5,
-	 0xb07cc616},
-	{0x103279db, 0x00000006, 0x0000039b, 0xca09b8a0, 0x77d62892,
-	 0xbf943b6c},
-	{0x1cba3172, 0x00000027, 0x000001c8, 0xcb377194, 0xebe682db,
-	 0x2c01af1c},
-	{0x8f613739, 0x0000000c, 0x000001df, 0xb4b0bc87, 0x7710bd43,
-	 0x0fe5f56d},
-	{0x1c6aa90d, 0x0000001b, 0x0000053c, 0x70559245, 0xda7894ac,
-	 0xf8943b2d},
-	{0xaabe5b93, 0x0000003d, 0x00000715, 0xcdbf42fa, 0x0c3b99e7,
-	 0xe4d89272},
-	{0xf15dd038, 0x00000006, 0x000006db, 0x6e104aea, 0x8d5967f2,
-	 0x7c2f6bbb},
-	{0x584dd49c, 0x00000020, 0x000007bc, 0x36b6cfd6, 0xad4e23b2,
-	 0xabbf388b},
-	{0x5d8c9506, 0x00000020, 0x00000470, 0x4c62378e, 0x31d92640,
-	 0x1dca1f4e},
-	{0xb80d17b0, 0x00000032, 0x00000346, 0x22a5bb88, 0x9a7ec89f,
-	 0x5c170e23},
-	{0xdaf0592e, 0x00000023, 0x000007b0, 0x3cab3f99, 0x9b1fdd99,
-	 0xc0e9d672},
-	{0x4793cc85, 0x0000000d, 0x00000706, 0xe82e04f6, 0xed3db6b7,
-	 0xc18bdc86},
-	{0x82ebf64e, 0x00000009, 0x000007c3, 0x69d590a9, 0x9efa8499,
-	 0xa874fcdd},
-	{0xb18a0319, 0x00000026, 0x000007db, 0x1cf98dcc, 0x8fa9ad6a,
-	 0x9dc0bb48},
+	{0x674bf11d, 0x00000038, 0x00000542, 0x0af6d466, 0xd8b6e4c1, 0xf6e93d6c},
+	{0x35c672c6, 0x0000003a, 0x000001aa, 0xc6d3dfba, 0x28aaf3ad, 0x0fe92aca},
+	{0x496da28e, 0x00000039, 0x000005af, 0xd933660f, 0x5d57e81f, 0x52e1ebb8},
+	{0x09a9b90e, 0x00000027, 0x000001f8, 0xb45fe007, 0xf45fca9a, 0x0798af9a},
+	{0xdc97e5a9, 0x00000025, 0x000003b6, 0xf81a3562, 0xe0126ba2, 0x18eb3152},
+	{0x47c58900, 0x0000000a, 0x000000b9, 0x8e58eccf, 0xf3afc793, 0xd00d08c7},
+	{0x292561e8, 0x0000000c, 0x00000403, 0xa2ba8aaf, 0x0b797aed, 0x8ba966bc},
+	{0x415037f6, 0x00000003, 0x00000676, 0xa17d52e8, 0x7f0fdf35, 0x11d694a2},
+	{0x3466e707, 0x00000026, 0x00000042, 0x258319be, 0x75c484a2, 0x6ab3208d},
+	{0xafd1281b, 0x00000023, 0x000002ee, 0x4428eaf8, 0x06c7ad10, 0xba4603c5},
+	{0xd3857b18, 0x00000028, 0x000004a2, 0x5c430821, 0xb062b7cb, 0xe6071c6f},
+	{0x1d825a8f, 0x0000002b, 0x0000050b, 0xd2c45f0c, 0xd68634e0, 0x179ec30a},
+	{0x5033e3bc, 0x0000000b, 0x00000078, 0xa3ea4113, 0xac6d31fb, 0x0903beb8},
+	{0x94f1fb5e, 0x0000000f, 0x000003a2, 0xfbfc50b1, 0x3cfe50ed, 0x6a7cb4fa},
+	{0xc9a0fe14, 0x00000009, 0x00000473, 0x5fb61894, 0x87070591, 0xdb535801},
+	{0x88a034b1, 0x0000001c, 0x000005ad, 0xc1b16053, 0x46f95c67, 0x92bed597},
+	{0xf0f72239, 0x00000020, 0x0000026d, 0xa6fa58f3, 0xf8c2c1dd, 0x192a3f1b},
+	{0xcc20a5e3, 0x0000003b, 0x0000067a, 0x7740185a, 0x308b979a, 0xccbaec1a},
+	{0xce589c95, 0x0000002b, 0x00000641, 0xd055e987, 0x40aae25b, 0x7eabae4d},
+	{0x78edc885, 0x00000035, 0x000005be, 0xa39cb14b, 0x035b0d1f, 0x28c72982},
+	{0x9d40a377, 0x0000003b, 0x00000038, 0x1f47ccd2, 0x197fbc9d, 0xc3cd4d18},
+	{0x703d0e01, 0x0000003c, 0x000006f1, 0x88735e7c, 0xfed57c5a, 0xbca8f0e7},
+	{0x776bf505, 0x0000000f, 0x000005b2, 0x5cc4fc01, 0xf32efb97, 0x713f60b3},
+	{0x4a3e7854, 0x00000027, 0x000004b8, 0x8d923c82, 0x0cbfb4a2, 0xebd08fd5},
+	{0x209172dd, 0x0000003b, 0x00000356, 0xb89e9c2b, 0xd7868138, 0x64406c59},
+	{0x3ba4cc5b, 0x0000002f, 0x00000203, 0xe51601a9, 0x5b2a1032, 0x7421890e},
+	{0xfc62f297, 0x00000000, 0x00000079, 0x71a8e1a2, 0x5d88685f, 0xe9347603},
+	{0x64280b8b, 0x00000016, 0x000007ab, 0x0fa7a30c, 0xda3a455f, 0x1bef9060},
+	{0x97dd724b, 0x00000033, 0x000007ad, 0x5788b2f4, 0xd7326d32, 0x34720072},
+	{0x61394b52, 0x00000035, 0x00000571, 0xc66525f1, 0xcabe7fef, 0x48310f59},
+	{0x29b4faff, 0x00000024, 0x0000006e, 0xca13751e, 0x993648e0, 0x783a4213},
+	{0x29bfb1dc, 0x0000000b, 0x00000244, 0x436c43f7, 0x429f7a59, 0x9e8efd41},
+	{0x86ae934b, 0x00000035, 0x00000104, 0x0760ec93, 0x9cf7d0f4, 0xfc3d34a5},
+	{0xc4c1024e, 0x0000002e, 0x000006b1, 0x6516a3ec, 0x19321f9c, 0x17a52ae2},
+	{0x3287a80a, 0x00000026, 0x00000496, 0x0b257eb1, 0x754ebd51, 0x886d935a},
+	{0xa4db423e, 0x00000023, 0x0000045d, 0x9b3a66dc, 0x873e9f11, 0xeaaeaeb2},
+	{0x7a1078df, 0x00000015, 0x0000014a, 0x8c2484c5, 0x6a628659, 0x8e900a4b},
+	{0x6048bd5b, 0x00000006, 0x0000006a, 0x897e3559, 0xac9961af, 0xd74662b1},
+	{0xd8f9ea20, 0x0000003d, 0x00000277, 0x60eb905b, 0xed2aaf99, 0xd26752ba},
+	{0xea5ec3b4, 0x0000002a, 0x000004fe, 0x869965dc, 0x6c1f833b, 0x8b1fcd62},
+	{0x2dfb005d, 0x00000016, 0x00000345, 0x6a3b117e, 0xf05e8521, 0xf54342fe},
+	{0x5a214ade, 0x00000020, 0x000005b6, 0x467f70be, 0xcb22ccd3, 0x5b95b988},
+	{0xf0ab9cca, 0x00000032, 0x00000515, 0xed223df3, 0x7f3ef01d, 0x2e1176be},
+	{0x91b444f9, 0x0000002e, 0x000007f8, 0x84e9a983, 0x5676756f, 0x66120546},
+	{0x1b5d2ddb, 0x0000002e, 0x0000012c, 0xba638c4c, 0x3f42047b, 0xf256a5cc},
+	{0xd824d1bb, 0x0000003a, 0x000007b5, 0x6288653b, 0x3a3ebea0, 0x4af1dd69},
+	{0x0470180c, 0x00000034, 0x000001f0, 0x9d5b80d6, 0x3de08195, 0x56f0a04a},
+	{0xffaa3a3f, 0x00000036, 0x00000299, 0xf3a82ab8, 0x53e0c13d, 0x74f6b6b2},
+	{0x6406cfeb, 0x00000023, 0x00000600, 0xa920b8e8, 0xe4e2acf4, 0x085951fd},
+	{0xb24aaa38, 0x0000003e, 0x000004a1, 0x657cc328, 0x5077b2c3, 0xc65387eb},
+	{0x58b2ab7c, 0x00000039, 0x000002b4, 0x3a17ee7e, 0x9dcb3643, 0x1ca9257b},
+	{0x3db85970, 0x00000006, 0x000002b6, 0x95268b59, 0xb9812c10, 0xfd196d76},
+	{0x857830c5, 0x00000003, 0x00000590, 0x4ef439d5, 0xf042161d, 0x5ef88339},
+	{0xe1fcd978, 0x0000003e, 0x000007d8, 0xae8d8699, 0xce0a1ef5, 0x2c3714d9},
+	{0xb982a768, 0x00000016, 0x000006e0, 0x62fad3df, 0x5f8a067b, 0x58576548},
+	{0x1d581ce8, 0x0000001e, 0x0000058b, 0xf0f5da53, 0x26e39eee, 0xfd7c57de},
+	{0x2456719b, 0x00000025, 0x00000503, 0x4296ac64, 0xd50e4c14, 0xd5fedd59},
+	{0xfae6d8f2, 0x00000000, 0x0000055d, 0x057fdf2e, 0x2a31391a, 0x1cc3b17b},
+	{0xcba828e3, 0x00000039, 0x000002ce, 0xe3f22351, 0x8f00877b, 0x270eed73},
+	{0x13d25952, 0x0000000a, 0x0000072d, 0x76d4b4cc, 0x5eb67ec3, 0x91ecbb11},
+	{0x0342be3f, 0x00000015, 0x00000599, 0xec75d9f1, 0x9d4d2826, 0x05ed8d0c},
+	{0xeaa344e0, 0x00000014, 0x000004d8, 0x72a4c981, 0x2064ea06, 0x0b09ad5b},
+	{0xbbb52021, 0x0000003b, 0x00000272, 0x04af99fc, 0xaf042d35, 0xf8d511fb},
+	{0xb66384dc, 0x0000001d, 0x000007fc, 0xd7629116, 0x782bd801, 0x5ad832cc},
+	{0x616c01b6, 0x00000022, 0x000002c8, 0x5b1dab30, 0x783ce7d2, 0x1214d196},
+	{0xce2bdaad, 0x00000016, 0x0000062a, 0x932535c8, 0x3f02926d, 0x5747218a},
+	{0x00fe84d7, 0x00000005, 0x00000205, 0x850e50aa, 0x753d649c, 0xde8f14de},
+	{0xbebdcb4c, 0x00000006, 0x0000055d, 0xbeaa37a2, 0x2d8c9eba, 0x3563b7b9},
+	{0xd8b1a02a, 0x00000010, 0x00000387, 0x5017d2fc, 0x503541a5, 0x071475d0},
+	{0x3b96cad2, 0x00000036, 0x00000347, 0x1d2372ae, 0x926cd90b, 0x54c79d60},
+	{0xc94c1ed7, 0x00000005, 0x0000038b, 0x9e9fdb22, 0x144a9178, 0x4c53eee6},
+	{0x1aad454e, 0x00000025, 0x000002b2, 0xc3f6315c, 0x5c7a35b3, 0x10137a3c},
+	{0xa4fec9a6, 0x00000000, 0x000006d6, 0x90be5080, 0xa4107605, 0xaa9d6c73},
+	{0x1bbe71e2, 0x0000001f, 0x000002fd, 0x4e504c3b, 0x284ccaf1, 0xb63d23e7},
+	{0x4201c7e4, 0x00000002, 0x000002b7, 0x7822e3f9, 0x0cc912a9, 0x7f53e9cf},
+	{0x23fddc96, 0x00000003, 0x00000627, 0x8a385125, 0x07767e78, 0x13c1cd83},
+	{0xd82ba25c, 0x00000016, 0x0000063e, 0x98e4148a, 0x283330c9, 0x49ff5867},
+	{0x786f2032, 0x0000002d, 0x0000060f, 0xf201600a, 0xf561bfcd, 0x8467f211},
+	{0xfebe4e1f, 0x0000002a, 0x000004f2, 0x95e51961, 0xfd80dcab, 0x3f9683b2},
+	{0x1a6e0a39, 0x00000008, 0x00000672, 0x8af6c2a5, 0x78dd84cb, 0x76a3f874},
+	{0x56000ab8, 0x0000000e, 0x000000e5, 0x36bacb8f, 0x22ee1f77, 0x863b702f},
+	{0x4717fe0c, 0x00000000, 0x000006ec, 0x8439f342, 0x5c8e03da, 0xdc6c58ff},
+	{0xd5d5d68e, 0x0000003c, 0x000003a3, 0x46fff083, 0x177d1b39, 0x0622cc95},
+	{0xc25dd6c6, 0x00000024, 0x000006c0, 0x5ceb8eb4, 0x892b0d16, 0xe85605cd},
+	{0xe9b11300, 0x00000023, 0x00000683, 0x07a5d59a, 0x6c6a3208, 0x31da5f06},
+	{0x95cd285e, 0x00000001, 0x00000047, 0x7b3a4368, 0x0202c07e, 0xa1f2e784},
+	{0xd9245a25, 0x0000001e, 0x000003a6, 0xd33c1841, 0x1936c0d5, 0xb07cc616},
+	{0x103279db, 0x00000006, 0x0000039b, 0xca09b8a0, 0x77d62892, 0xbf943b6c},
+	{0x1cba3172, 0x00000027, 0x000001c8, 0xcb377194, 0xebe682db, 0x2c01af1c},
+	{0x8f613739, 0x0000000c, 0x000001df, 0xb4b0bc87, 0x7710bd43, 0x0fe5f56d},
+	{0x1c6aa90d, 0x0000001b, 0x0000053c, 0x70559245, 0xda7894ac, 0xf8943b2d},
+	{0xaabe5b93, 0x0000003d, 0x00000715, 0xcdbf42fa, 0x0c3b99e7, 0xe4d89272},
+	{0xf15dd038, 0x00000006, 0x000006db, 0x6e104aea, 0x8d5967f2, 0x7c2f6bbb},
+	{0x584dd49c, 0x00000020, 0x000007bc, 0x36b6cfd6, 0xad4e23b2, 0xabbf388b},
+	{0x5d8c9506, 0x00000020, 0x00000470, 0x4c62378e, 0x31d92640, 0x1dca1f4e},
+	{0xb80d17b0, 0x00000032, 0x00000346, 0x22a5bb88, 0x9a7ec89f, 0x5c170e23},
+	{0xdaf0592e, 0x00000023, 0x000007b0, 0x3cab3f99, 0x9b1fdd99, 0xc0e9d672},
+	{0x4793cc85, 0x0000000d, 0x00000706, 0xe82e04f6, 0xed3db6b7, 0xc18bdc86},
+	{0x82ebf64e, 0x00000009, 0x000007c3, 0x69d590a9, 0x9efa8499, 0xa874fcdd},
+	{0xb18a0319, 0x00000026, 0x000007db, 0x1cf98dcc, 0x8fa9ad6a, 0x9dc0bb48},
 };
 
 #include <linux/time.h>
@@ -1050,6 +1031,40 @@ static int __init crc32c_test(void)
 	return 0;
 }
 
+static int __init crc32c_combine_test(void)
+{
+	int i, j;
+	int errors = 0, runs = 0;
+
+	for (i = 0; i < 100; i++) {
+		u32 crc_full;
+
+		crc_full = __crc32c_le(test[i].crc, test_buf + test[i].start,
+				       test[i].length);
+		for (j = 0; j <= test[i].length; ++j) {
+			u32 crc1, crc2;
+			u32 len1 = j, len2 = test[i].length - j;
+
+			crc1 = __crc32c_le(test[i].crc, test_buf +
+					   test[i].start, len1);
+			crc2 = __crc32c_le(0, test_buf + test[i].start +
+					   len1, len2);
+
+			if (!(crc_full == __crc32c_le_combine(crc1, crc2, len2) &&
+			      crc_full == test[i].crc32c_le))
+				errors++;
+			runs++;
+		}
+	}
+
+	if (errors)
+		pr_warn("crc32c_combine: %d/%d self tests failed\n", errors, runs);
+	else
+		pr_info("crc32c_combine: %d self tests passed\n", runs);
+
+	return 0;
+}
+
 static int __init crc32_test(void)
 {
 	int i;
@@ -1109,10 +1124,48 @@ static int __init crc32_test(void)
 	return 0;
 }
 
+static int __init crc32_combine_test(void)
+{
+	int i, j;
+	int errors = 0, runs = 0;
+
+	for (i = 0; i < 100; i++) {
+		u32 crc_full;
+
+		crc_full = crc32_le(test[i].crc, test_buf + test[i].start,
+				    test[i].length);
+		for (j = 0; j <= test[i].length; ++j) {
+			u32 crc1, crc2;
+			u32 len1 = j, len2 = test[i].length - j;
+
+			crc1 = crc32_le(test[i].crc, test_buf +
+					test[i].start, len1);
+			crc2 = crc32_le(0, test_buf + test[i].start +
+					len1, len2);
+
+			if (!(crc_full == crc32_le_combine(crc1, crc2, len2) &&
+			      crc_full == test[i].crc_le))
+				errors++;
+			runs++;
+		}
+	}
+
+	if (errors)
+		pr_warn("crc32_combine: %d/%d self tests failed\n", errors, runs);
+	else
+		pr_info("crc32_combine: %d self tests passed\n", runs);
+
+	return 0;
+}
+
 static int __init crc32test_init(void)
 {
 	crc32_test();
 	crc32c_test();
+
+	crc32_combine_test();
+	crc32c_combine_test();
+
 	return 0;
 }
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 0ab32faa520f..31aab5376cb4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1928,9 +1928,8 @@ fault:
 EXPORT_SYMBOL(skb_store_bits);
 
 /* Checksum skb data. */
-
-__wsum skb_checksum(const struct sk_buff *skb, int offset,
-			  int len, __wsum csum)
+__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
+		      __wsum csum, const struct skb_checksum_ops *ops)
 {
 	int start = skb_headlen(skb);
 	int i, copy = start - offset;
@@ -1941,7 +1940,7 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 	if (copy > 0) {
 		if (copy > len)
 			copy = len;
-		csum = csum_partial(skb->data + offset, copy, csum);
+		csum = ops->update(skb->data + offset, copy, csum);
 		if ((len -= copy) == 0)
 			return csum;
 		offset += copy;
@@ -1962,10 +1961,10 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 			if (copy > len)
 				copy = len;
 			vaddr = kmap_atomic(skb_frag_page(frag));
-			csum2 = csum_partial(vaddr + frag->page_offset +
-					     offset - start, copy, 0);
+			csum2 = ops->update(vaddr + frag->page_offset +
+					    offset - start, copy, 0);
 			kunmap_atomic(vaddr);
-			csum = csum_block_add(csum, csum2, pos);
+			csum = ops->combine(csum, csum2, pos, copy);
 			if (!(len -= copy))
 				return csum;
 			offset += copy;
@@ -1984,9 +1983,9 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 			__wsum csum2;
 			if (copy > len)
 				copy = len;
-			csum2 = skb_checksum(frag_iter, offset - start,
-					     copy, 0);
-			csum = csum_block_add(csum, csum2, pos);
+			csum2 = __skb_checksum(frag_iter, offset - start,
+					       copy, 0, ops);
+			csum = ops->combine(csum, csum2, pos, copy);
 			if ((len -= copy) == 0)
 				return csum;
 			offset += copy;
@@ -1998,6 +1997,18 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 
 	return csum;
 }
+EXPORT_SYMBOL(__skb_checksum);
+
+__wsum skb_checksum(const struct sk_buff *skb, int offset,
+		    int len, __wsum csum)
+{
+	const struct skb_checksum_ops ops = {
+		.update  = csum_partial,
+		.combine = csum_block_add_ext,
+	};
+
+	return __skb_checksum(skb, offset, len, csum, &ops);
+}
 EXPORT_SYMBOL(skb_checksum);
 
 /* Both of above in one bottle. */
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 319137340d15..e650978daf27 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -390,7 +390,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	__u8 has_data = 0;
 	struct dst_entry *dst = tp->dst;
 	unsigned char *auth = NULL;	/* pointer to auth in skb data */
-	__u32 cksum_buf_len = sizeof(struct sctphdr);
 
 	pr_debug("%s: packet:%p\n", __func__, packet);
 
@@ -493,7 +492,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 		if (chunk == packet->auth)
 			auth = skb_tail_pointer(nskb);
 
-		cksum_buf_len += chunk->skb->len;
 		memcpy(skb_put(nskb, chunk->skb->len),
 			       chunk->skb->data, chunk->skb->len);
 
@@ -538,12 +536,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
 	if (!sctp_checksum_disable) {
 		if (!(dst->dev->features & NETIF_F_SCTP_CSUM) ||
 		    (dst_xfrm(dst) != NULL) || packet->ipfragok) {
-			__u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
-
-			/* 3) Put the resultant value into the checksum field in the
-			 *    common header, and leave the rest of the bits unchanged.
-			 */
-			sh->checksum = sctp_end_cksum(crc32);
+			sh->checksum = sctp_compute_cksum(nskb, 0);
 		} else {
 			/* no need to seed pseudo checksum for SCTP */
 			nskb->ip_summed = CHECKSUM_PARTIAL;