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>

2 files changed, 22 insertions, 18 deletions

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;