On 10/13/16, 5:57 PM, Tom Herbert wrote:
> Add a dst_cache to ila_lwt structure. This holds a cached route for the
> translated address. In ila_output we now perform a route lookup after
> translation and if possible (destination in original route is full 128
> bits) we set the dst_cache. Subsequent calls to ila_output can then use
> the cache to avoid the route lookup.
>
> This eliminates the need to set the gateway on ILA routes as previously
> was being done. Now we can do something like:
>
> ./ip route add 3333::2000:0:0:2/128 encap ila 2222:0:0:2 \
> csum-mode neutral-map dev eth0 ## No via needed!
>
> Signed-off-by: Tom Herbert <t...@herbertland.com>
> ---
Acked-by: Roopa Prabhu <ro...@cumulusnetworks.com>
This is a nice way to cache and redirect to a new dst.
This removes the last and only user of lwt orig_output. we can drop it
subsequently. But since orig_input is still in use, probably better to keep it
around for symmetry and for other uses in the future.
thanks.
> net/ipv6/ila/ila_lwt.c | 76
> +++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 72 insertions(+), 4 deletions(-)
>
> diff --git a/net/ipv6/ila/ila_lwt.c b/net/ipv6/ila/ila_lwt.c
> index e50c27a..df14b00 100644
> --- a/net/ipv6/ila/ila_lwt.c
> +++ b/net/ipv6/ila/ila_lwt.c
> @@ -6,29 +6,80 @@
> #include <linux/socket.h>
> #include <linux/types.h>
> #include <net/checksum.h>
> +#include <net/dst_cache.h>
> #include <net/ip.h>
> #include <net/ip6_fib.h>
> +#include <net/ip6_route.h>
> #include <net/lwtunnel.h>
> #include <net/protocol.h>
> #include <uapi/linux/ila.h>
> #include "ila.h"
>
> +struct ila_lwt {
> + struct ila_params p;
> + struct dst_cache dst_cache;
> + u32 connected : 1;
> +};
> +
> +static inline struct ila_lwt *ila_lwt_lwtunnel(
> + struct lwtunnel_state *lwstate)
> +{
> + return (struct ila_lwt *)lwstate->data;
> +}
> +
> static inline struct ila_params *ila_params_lwtunnel(
> struct lwtunnel_state *lwstate)
> {
> - return (struct ila_params *)lwstate->data;
> + return &((struct ila_lwt *)lwstate->data)->p;
> }
>
> static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
> {
> - struct dst_entry *dst = skb_dst(skb);
> + struct dst_entry *orig_dst = skb_dst(skb);
> + struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
> + struct dst_entry *dst;
> + int err = -EINVAL;
>
> if (skb->protocol != htons(ETH_P_IPV6))
> goto drop;
>
> - ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), true);
> + ila_update_ipv6_locator(skb, ila_params_lwtunnel(orig_dst->lwtstate),
> + true);
>
> - return dst->lwtstate->orig_output(net, sk, skb);
> + dst = dst_cache_get(&ilwt->dst_cache);
> + if (unlikely(!dst)) {
> + struct ipv6hdr *ip6h = ipv6_hdr(skb);
> + struct flowi6 fl6;
> +
> + /* Lookup a route for the new destination. Take into
> + * account that the base route may already have a gateway.
> + */
> +
> + memset(&fl6, 0, sizeof(fl6));
> + fl6.flowi6_oif = orig_dst->dev->ifindex;
> + fl6.flowi6_iif = LOOPBACK_IFINDEX;
> + fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
> + &ip6h->daddr);
> +
> + dst = ip6_route_output(net, NULL, &fl6);
> + if (dst->error) {
> + err = -EHOSTUNREACH;
> + dst_release(dst);
> + goto drop;
> + }
> +
> + dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
> + if (IS_ERR(dst)) {
> + err = PTR_ERR(dst);
> + goto drop;
> + }
> +
> + if (ilwt->connected)
> + dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
> + }
> +
> + skb_dst_set(skb, dst);
> + return dst_output(dev_net(skb_dst(skb)->dev), sk, skb);
>
> drop:
> kfree_skb(skb);
> @@ -60,6 +111,7 @@ static int ila_build_state(struct net_device *dev, struct
> nlattr *nla,
> unsigned int family, const void *cfg,
> struct lwtunnel_state **ts)
> {
> + struct ila_lwt *ilwt;
> struct ila_params *p;
> struct nlattr *tb[ILA_ATTR_MAX + 1];
> size_t encap_len = sizeof(*p);
> @@ -99,6 +151,13 @@ static int ila_build_state(struct net_device *dev, struct
> nlattr *nla,
> if (!newts)
> return -ENOMEM;
>
> + ilwt = ila_lwt_lwtunnel(newts);
> + ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
> + if (ret) {
> + kfree(newts);
> + return ret;
> + }
> +
> newts->len = encap_len;
> p = ila_params_lwtunnel(newts);
>
> @@ -120,11 +179,19 @@ static int ila_build_state(struct net_device *dev,
> struct nlattr *nla,
> newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
> LWTUNNEL_STATE_INPUT_REDIRECT;
>
> + if (cfg6->fc_dst_len == sizeof(struct in6_addr))
> + ilwt->connected = 1;
> +
> *ts = newts;
>
> return 0;
> }
>
> +static void ila_destroy_state(struct lwtunnel_state *lwt)
> +{
> + dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
> +}
> +
> static int ila_fill_encap_info(struct sk_buff *skb,
> struct lwtunnel_state *lwtstate)
> {
> @@ -159,6 +226,7 @@ static int ila_encap_cmp(struct lwtunnel_state *a, struct
> lwtunnel_state *b)
>
> static const struct lwtunnel_encap_ops ila_encap_ops = {
> .build_state = ila_build_state,
> + .destroy_state = ila_destroy_state,
> .output = ila_output,
> .input = ila_input,
> .fill_encap = ila_fill_encap_info,
