Commit 707a2ca4 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

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: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e00431bc

net/ipv6/ila/ila.h

+2 −1
Original line number Diff line number Diff line
@@ -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);

net/ipv6/ila/ila_common.c

+4 −2
Original line number Diff line number Diff line
@@ -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);
@@ -114,6 +115,7 @@ 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.

		 */

		if (!set_csum_neutral)

			ila_csum_do_neutral(iaddr, p);

	} else {

		switch (p->csum_mode) {

net/ipv6/ila/ila_lwt.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

net/ipv6/ila/ila_xlat.c

+4 −4
Original line number Diff line number Diff line
@@ -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();

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