Merge branch 'ila-csum-neutral'

Tom Herbert says:

====================
ila: Support for checksum neutral translations

This patch set updates ILA to support draft-herbert-nvo3-ila-02. The
primary addition is support checksum neutral ILA translation.
This allows address to be performed and still keep any transport
layer checksums that include the addresses in their pseudo header to
still be correct without the translator needing to parse L4.

Other items are:
   - Structures for ILA addresses, identifiers, locators
   - Disallow translation on non-ILA addresses (check by
     type in identifier).
   - Change xlat (nf_input) to translates solely based
     on matching locators not identifiers (since identifiers
     are not obfuscated by checksum neutral).
   - Side effect if above is that multiple ILA domains are
     supported. Each local locator can map to a different
     SIR address (ILA domain), and each domain defines its
     own identifier space.

Tested: Ran TCP_RR with 200 cnxs. ILA performance is slightly better
than previously since we are not longer parsing L4 for checksum
handling. I amd seeing about 1% performance overhead. Also ran
TCP_STREAM and tested non-ILA address (type=0) are not translated.

v2: Fix compilation errors
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 76 insertions, 5 deletions

diff --git a/net/ipv6/ila/ila_common.c b/net/ipv6/ila/ila_common.c
index 30613050e4ca..0e94042d1289 100644
--- a/net/ipv6/ila/ila_common.c
+++ b/net/ipv6/ila/ila_common.c
@@ -15,20 +15,52 @@
 
 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
 {
-	if (*(__be64 *)&ip6h->daddr == p->locator_match)
+	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
+
+	if (p->locator_match.v64)
 		return p->csum_diff;
 	else
-		return compute_csum_diff8((__be32 *)&ip6h->daddr,
+		return compute_csum_diff8((__be32 *)&iaddr->loc,
+					  (__be32 *)&p->locator);
+}
+
+static void ila_csum_do_neutral(struct ila_addr *iaddr,
+				struct ila_params *p)
+{
+	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
+	__wsum diff, fval;
+
+	/* Check if checksum adjust value has been cached */
+	if (p->locator_match.v64) {
+		diff = p->csum_diff;
+	} else {
+		diff = compute_csum_diff8((__be32 *)iaddr,
 					  (__be32 *)&p->locator);
+	}
+
+	fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
+			~CSUM_NEUTRAL_FLAG : CSUM_NEUTRAL_FLAG);
+
+	diff = csum_add(diff, fval);
+
+	*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
+
+	/* Flip the csum-neutral bit. Either we are doing a SIR->ILA
+	 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
+	 * and the C-bit is not set, or we are doing an ILA-SIR
+	 * tranlsation and the C-bit is set.
+	 */
+	iaddr->ident.csum_neutral ^= 1;
 }
 
-void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
+static void ila_csum_adjust_transport(struct sk_buff *skb,
+				      struct ila_params *p)
 {
 	__wsum diff;
 	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 	size_t nhoff = sizeof(struct ipv6hdr);
 
-	/* First update checksum */
 	switch (ip6h->nexthdr) {
 	case NEXTHDR_TCP:
 		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
@@ -68,7 +100,46 @@ void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
 	}
 
 	/* Now change destination address */
-	*(__be64 *)&ip6h->daddr = p->locator;
+	iaddr->loc = p->locator;
+}
+
+void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
+{
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
+
+	/* First deal with the transport checksum */
+	if (ila_csum_neutral_set(iaddr->ident)) {
+		/* C-bit is set in the locator indicating that this
+		 * is a locator being translated to a SIR address.
+		 * Perform (receiver) checksum-neutral translation.
+		 */
+		ila_csum_do_neutral(iaddr, p);
+	} else {
+		switch (p->csum_mode) {
+		case ILA_CSUM_ADJUST_TRANSPORT:
+			ila_csum_adjust_transport(skb, p);
+			break;
+		case ILA_CSUM_NEUTRAL_MAP:
+			ila_csum_do_neutral(iaddr, p);
+			break;
+		case ILA_CSUM_NO_ACTION:
+			break;
+		}
+	}
+
+	/* Now change destination address */
+	iaddr->loc = p->locator;
+}
+
+void ila_init_saved_csum(struct ila_params *p)
+{
+	if (!p->locator_match.v64)
+		return;
+
+	p->csum_diff = compute_csum_diff8(
+				(__be32 *)&p->locator_match,
+				(__be32 *)&p->locator);
 }
 
 static int __init ila_init(void)