From d33e455337ea2c71d09d7f4367d6ad6dd32b6965 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 14 Dec 2010 13:01:14 -0800 Subject: net: Abstract default MTU metric calculation behind an accessor. Like RTAX_ADVMSS, make the default calculation go through a dst_ops method rather than caching the computation in the routing cache entries. Now dst metrics are pretty much left as-is when new entries are created, thus optimizing metric sharing becomes a real possibility. Signed-off-by: David S. Miller --- include/net/dst.h | 15 ++++++++------- include/net/dst_ops.h | 1 + net/decnet/dn_route.c | 10 ++++++++-- net/ipv4/route.c | 29 ++++++++++++++++++++--------- net/ipv6/route.c | 37 ++++++++++++++++--------------------- net/xfrm/xfrm_policy.c | 7 +++++++ 6 files changed, 60 insertions(+), 39 deletions(-) diff --git a/include/net/dst.h b/include/net/dst.h index 03a1c3d..93b0310 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -113,7 +113,8 @@ static inline u32 dst_metric(const struct dst_entry *dst, const int metric) { WARN_ON_ONCE(metric == RTAX_HOPLIMIT || - metric == RTAX_ADVMSS); + metric == RTAX_ADVMSS || + metric == RTAX_MTU); return dst_metric_raw(dst, metric); } @@ -156,11 +157,11 @@ dst_feature(const struct dst_entry *dst, u32 feature) static inline u32 dst_mtu(const struct dst_entry *dst) { - u32 mtu = dst_metric(dst, RTAX_MTU); - /* - * Alexey put it here, so ask him about it :) - */ - barrier(); + u32 mtu = dst_metric_raw(dst, RTAX_MTU); + + if (!mtu) + mtu = dst->ops->default_mtu(dst); + return mtu; } @@ -186,7 +187,7 @@ dst_allfrag(const struct dst_entry *dst) } static inline int -dst_metric_locked(struct dst_entry *dst, int metric) +dst_metric_locked(const struct dst_entry *dst, int metric) { return dst_metric(dst, RTAX_LOCK) & (1<dev, dst_mtu(dst)); } +static unsigned int dn_dst_default_mtu(const struct dst_entry *dst) +{ + return dst->dev->mtu; +} + static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res) { struct dn_fib_info *fi = res->fi; @@ -825,8 +832,7 @@ static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res) rt->dst.neighbour = n; } - if (dst_metric(&rt->dst, RTAX_MTU) == 0 || - dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu) + if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu) dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu); metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS); if (metric) { diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 8099733..ae52096 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -140,6 +140,7 @@ static unsigned long expires_ljiffies; static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); static unsigned int ipv4_default_advmss(const struct dst_entry *dst); +static unsigned int ipv4_default_mtu(const struct dst_entry *dst); static void ipv4_dst_destroy(struct dst_entry *dst); static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); static void ipv4_link_failure(struct sk_buff *skb); @@ -157,6 +158,7 @@ static struct dst_ops ipv4_dst_ops = { .gc = rt_garbage_collect, .check = ipv4_dst_check, .default_advmss = ipv4_default_advmss, + .default_mtu = ipv4_default_mtu, .destroy = ipv4_dst_destroy, .ifdown = ipv4_dst_ifdown, .negative_advice = ipv4_negative_advice, @@ -1812,6 +1814,23 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst) return advmss; } +static unsigned int ipv4_default_mtu(const struct dst_entry *dst) +{ + unsigned int mtu = dst->dev->mtu; + + if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { + const struct rtable *rt = (const struct rtable *) dst; + + if (rt->rt_gateway != rt->rt_dst && mtu > 576) + mtu = 576; + } + + if (mtu > IP_MAX_MTU) + mtu = IP_MAX_MTU; + + return mtu; +} + static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag) { struct dst_entry *dst = &rt->dst; @@ -1822,18 +1841,10 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag) FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) rt->rt_gateway = FIB_RES_GW(*res); dst_import_metrics(dst, fi->fib_metrics); - if (fi->fib_mtu == 0) { - dst_metric_set(dst, RTAX_MTU, dst->dev->mtu); - if (dst_metric_locked(dst, RTAX_MTU) && - rt->rt_gateway != rt->rt_dst && - dst->dev->mtu > 576) - dst_metric_set(dst, RTAX_MTU, 576); - } #ifdef CONFIG_NET_CLS_ROUTE dst->tclassid = FIB_RES_NH(*res).nh_tclassid; #endif - } else - dst_metric_set(dst, RTAX_MTU, dst->dev->mtu); + } if (dst_mtu(dst) > IP_MAX_MTU) dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU); diff --git a/net/ipv6/route.c b/net/ipv6/route.c index d9cb832..e7efb26 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -77,6 +77,7 @@ static struct rt6_info * ip6_rt_copy(struct rt6_info *ort); static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie); static unsigned int ip6_default_advmss(const struct dst_entry *dst); +static unsigned int ip6_default_mtu(const struct dst_entry *dst); static struct dst_entry *ip6_negative_advice(struct dst_entry *); static void ip6_dst_destroy(struct dst_entry *); static void ip6_dst_ifdown(struct dst_entry *, @@ -105,6 +106,7 @@ static struct dst_ops ip6_dst_ops_template = { .gc_thresh = 1024, .check = ip6_dst_check, .default_advmss = ip6_default_advmss, + .default_mtu = ip6_default_mtu, .destroy = ip6_dst_destroy, .ifdown = ip6_dst_ifdown, .negative_advice = ip6_negative_advice, @@ -937,8 +939,6 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu) } } -static int ipv6_get_mtu(struct net_device *dev); - static unsigned int ip6_default_advmss(const struct dst_entry *dst) { struct net_device *dev = dst->dev; @@ -961,6 +961,20 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst) return mtu; } +static unsigned int ip6_default_mtu(const struct dst_entry *dst) +{ + unsigned int mtu = IPV6_MIN_MTU; + struct inet6_dev *idev; + + rcu_read_lock(); + idev = __in6_dev_get(dst->dev); + if (idev) + mtu = idev->cnf.mtu6; + rcu_read_unlock(); + + return mtu; +} + static struct dst_entry *icmp6_dst_gc_list; static DEFINE_SPINLOCK(icmp6_dst_lock); @@ -995,7 +1009,6 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev, rt->rt6i_nexthop = neigh; atomic_set(&rt->dst.__refcnt, 1); dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 255); - dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev)); rt->dst.output = ip6_output; #if 0 /* there's no chance to use these for ndisc */ @@ -1094,19 +1107,6 @@ out: Remove it only when all the things will work! */ -static int ipv6_get_mtu(struct net_device *dev) -{ - int mtu = IPV6_MIN_MTU; - struct inet6_dev *idev; - - rcu_read_lock(); - idev = __in6_dev_get(dev); - if (idev) - mtu = idev->cnf.mtu6; - rcu_read_unlock(); - return mtu; -} - int ip6_dst_hoplimit(struct dst_entry *dst) { int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); @@ -1315,8 +1315,6 @@ install_route: } } - if (!dst_mtu(&rt->dst)) - dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(dev)); rt->dst.dev = dev; rt->rt6i_idev = idev; rt->rt6i_table = table; @@ -1541,8 +1539,6 @@ void rt6_redirect(struct in6_addr *dest, struct in6_addr *src, ipv6_addr_copy(&nrt->rt6i_gateway, (struct in6_addr*)neigh->primary_key); nrt->rt6i_nexthop = neigh_clone(neigh); - /* Reset pmtu, it may be better */ - dst_metric_set(&nrt->dst, RTAX_MTU, ipv6_get_mtu(neigh->dev)); if (ip6_ins_rt(nrt)) goto out; @@ -1971,7 +1967,6 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev, rt->dst.output = ip6_output; rt->rt6i_dev = net->loopback_dev; rt->rt6i_idev = idev; - dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev)); dst_metric_set(&rt->dst, RTAX_HOPLIMIT, -1); rt->dst.obsolete = -1; diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 36936c8..8b3ef40 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2366,6 +2366,11 @@ static unsigned int xfrm_default_advmss(const struct dst_entry *dst) return dst_metric_advmss(dst->path); } +static unsigned int xfrm_default_mtu(const struct dst_entry *dst) +{ + return dst_mtu(dst->path); +} + int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) { struct net *net; @@ -2385,6 +2390,8 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) dst_ops->check = xfrm_dst_check; if (likely(dst_ops->default_advmss == NULL)) dst_ops->default_advmss = xfrm_default_advmss; + if (likely(dst_ops->default_mtu == NULL)) + dst_ops->default_mtu = xfrm_default_mtu; if (likely(dst_ops->negative_advice == NULL)) dst_ops->negative_advice = xfrm_negative_advice; if (likely(dst_ops->link_failure == NULL)) -- cgit v1.1