ila: Perform only one translation in forwarding path

When setting up ILA in a router we noticed that the the encapsulation
is invoked twice: once in the route input path and again upon route
output. To resolve this we add a flag set_csum_neutral for the
ila_update_ipv6_locator. If this flag is set and the checksum
neutral bit is also set we assume that checksum-neutral translation
has already been performed and take no further action. The
flag is set only in ila_output path. The flag is not set for ila_input and
ila_xlat.

Tested:

Used 3 netns to set to emulate a router and two hosts. The router
translates SIR addresses between the two destinations in other two netns.
Verified ping and netperf are functional.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ila/ila.h b/net/ipv6/ila/ila.h
index d08fd2d..e0170f6 100644 (file)
--- a/net/ipv6/ila/ila.h
+++ b/net/ipv6/ila/ila.h
@@ -109,7 +109,8 @@ static inline bool ila_csum_neutral_set(struct ila_identifier ident)
        return !!(ident.csum_neutral);
 }
 
-void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p);
+void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
+                            bool set_csum_neutral);
 
 void ila_init_saved_csum(struct ila_params *p);
 

diff --git a/net/ipv6/ila/ila_common.c b/net/ipv6/ila/ila_common.c
index 0e94042..b3d00be 100644 (file)
--- a/net/ipv6/ila/ila_common.c
+++ b/net/ipv6/ila/ila_common.c
@@ -103,7 +103,8 @@ static void ila_csum_adjust_transport(struct sk_buff *skb,
        iaddr->loc = p->locator;
 }
 
-void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
+void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
+                            bool set_csum_neutral)
 {
        struct ipv6hdr *ip6h = ipv6_hdr(skb);
        struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
@@ -114,7 +115,8 @@ void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
                 * is a locator being translated to a SIR address.
                 * Perform (receiver) checksum-neutral translation.
                 */
-               ila_csum_do_neutral(iaddr, p);
+               if (!set_csum_neutral)
+                       ila_csum_do_neutral(iaddr, p);
        } else {
                switch (p->csum_mode) {
                case ILA_CSUM_ADJUST_TRANSPORT:

diff --git a/net/ipv6/ila/ila_lwt.c b/net/ipv6/ila/ila_lwt.c
index 1dfb641..c8314c6 100644 (file)
--- a/net/ipv6/ila/ila_lwt.c
+++ b/net/ipv6/ila/ila_lwt.c
@@ -26,7 +26,7 @@ static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
        if (skb->protocol != htons(ETH_P_IPV6))
                goto drop;
 
-       ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
+       ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), true);
 
        return dst->lwtstate->orig_output(net, sk, skb);
 
@@ -42,7 +42,7 @@ static int ila_input(struct sk_buff *skb)
        if (skb->protocol != htons(ETH_P_IPV6))
                goto drop;
 
-       ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
+       ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), false);
 
        return dst->lwtstate->orig_input(skb);
 

diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index a90e572..e6eca5f 100644 (file)
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -210,14 +210,14 @@ static void ila_free_cb(void *ptr, void *arg)
        }
 }
 
-static int ila_xlat_addr(struct sk_buff *skb);
+static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral);
 
 static unsigned int
 ila_nf_input(void *priv,
             struct sk_buff *skb,
             const struct nf_hook_state *state)
 {
-       ila_xlat_addr(skb);
+       ila_xlat_addr(skb, false);
        return NF_ACCEPT;
 }
 
@@ -597,7 +597,7 @@ static struct pernet_operations ila_net_ops = {
        .size = sizeof(struct ila_net),
 };
 
-static int ila_xlat_addr(struct sk_buff *skb)
+static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral)
 {
        struct ila_map *ila;
        struct ipv6hdr *ip6h = ipv6_hdr(skb);
@@ -616,7 +616,7 @@ static int ila_xlat_addr(struct sk_buff *skb)
 
        ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
        if (ila)
-               ila_update_ipv6_locator(skb, &ila->xp.ip);
+               ila_update_ipv6_locator(skb, &ila->xp.ip, set_csum_neutral);
 
        rcu_read_unlock();