ipv6: Stop rt6_info from using inet_peer's metrics
inet_peer is indexed by the dst address alone. However, the fib6 tree could have multiple routing entries (rt6_info) for the same dst. For example, 1. A /128 dst via multiple gateways. 2. A RTF_CACHE route cloned from a /128 route. In the above cases, all of them will share the same metrics and step on each other. This patch will steer away from inet_peer's metrics and use dst_cow_metrics_generic() for everything. Change Highlights: 1. Remove rt6_cow_metrics() which currently acquires metrics from inet_peer for DST_HOST route (i.e. /128 route). 2. Add rt6i_pmtu to take care of the pmtu update to avoid creating a full size metrics just to override the RTAX_MTU. 3. After (2), the RTF_CACHE route can also share the metrics with its dst.from route, by: dst_init_metrics(&cache_rt->dst, dst_metrics_ptr(cache_rt->dst.from), true); 4. Stop creating RTF_CACHE route by cloning another RTF_CACHE route. Instead, directly clone from rt->dst. [ Currently, cloning from another RTF_CACHE is only possible during rt6_do_redirect(). Also, the old clone is removed from the tree immediately after the new clone is added. ] In case of cloning from an older redirect RTF_CACHE, it should work as before. In case of cloning from an older pmtu RTF_CACHE, this patch will forget the pmtu and re-learn it (if there is any) from the redirected route. The _rt6i_peer and DST_METRICS_FORCE_OVERWRITE will be removed in the next cleanup patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
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653437d02f
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4b32b5ad31
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@ -124,6 +124,7 @@ struct rt6_info {
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unsigned long _rt6i_peer;
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u32 rt6i_metric;
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u32 rt6i_pmtu;
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/* more non-fragment space at head required */
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unsigned short rt6i_nfheader_len;
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u8 rt6i_protocol;
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@ -189,15 +190,6 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
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rt0->rt6i_flags |= RTF_EXPIRES;
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}
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static inline void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
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{
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struct dst_entry *new = (struct dst_entry *) from;
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rt->rt6i_flags &= ~RTF_EXPIRES;
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dst_hold(new);
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rt->dst.from = new;
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}
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static inline void ip6_rt_put(struct rt6_info *rt)
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{
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/* dst_release() accepts a NULL parameter.
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@ -92,6 +92,7 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb, u32 mtu);
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static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb);
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static void rt6_dst_from_metrics_check(struct rt6_info *rt);
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static int rt6_score_route(struct rt6_info *rt, int oif, int strict);
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#ifdef CONFIG_IPV6_ROUTE_INFO
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@ -136,33 +137,12 @@ static struct inet_peer *rt6_get_peer_create(struct rt6_info *rt)
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static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old)
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{
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struct rt6_info *rt = (struct rt6_info *) dst;
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struct inet_peer *peer;
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u32 *p = NULL;
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struct rt6_info *rt = (struct rt6_info *)dst;
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if (!(rt->dst.flags & DST_HOST))
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if (rt->rt6i_flags & RTF_CACHE)
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return NULL;
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else
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return dst_cow_metrics_generic(dst, old);
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peer = rt6_get_peer_create(rt);
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if (peer) {
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u32 *old_p = __DST_METRICS_PTR(old);
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unsigned long prev, new;
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p = peer->metrics;
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if (inet_metrics_new(peer) ||
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(old & DST_METRICS_FORCE_OVERWRITE))
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memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
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new = (unsigned long) p;
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prev = cmpxchg(&dst->_metrics, old, new);
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if (prev != old) {
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p = __DST_METRICS_PTR(prev);
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if (prev & DST_METRICS_READ_ONLY)
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p = NULL;
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}
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}
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return p;
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}
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static inline const void *choose_neigh_daddr(struct rt6_info *rt,
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@ -323,7 +303,6 @@ static void ip6_dst_destroy(struct dst_entry *dst)
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struct inet6_dev *idev = rt->rt6i_idev;
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struct dst_entry *from = dst->from;
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if (!(rt->dst.flags & DST_HOST))
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dst_destroy_metrics_generic(dst);
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if (idev) {
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@ -333,11 +312,6 @@ static void ip6_dst_destroy(struct dst_entry *dst)
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dst->from = NULL;
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dst_release(from);
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if (rt6_has_peer(rt)) {
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struct inet_peer *peer = rt6_peer_ptr(rt);
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inet_putpeer(peer);
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}
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}
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static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
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@ -1003,6 +977,7 @@ redo_rt6_select:
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goto redo_fib6_lookup_lock;
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out2:
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rt6_dst_from_metrics_check(rt);
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rt->dst.lastuse = jiffies;
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rt->dst.__use++;
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@ -1111,6 +1086,13 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
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* Destination cache support functions
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*/
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static void rt6_dst_from_metrics_check(struct rt6_info *rt)
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{
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if (rt->dst.from &&
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dst_metrics_ptr(&rt->dst) != dst_metrics_ptr(rt->dst.from))
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dst_init_metrics(&rt->dst, dst_metrics_ptr(rt->dst.from), true);
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}
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static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
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{
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struct rt6_info *rt;
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@ -1127,6 +1109,8 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
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if (rt6_check_expired(rt))
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return NULL;
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rt6_dst_from_metrics_check(rt);
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return dst;
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}
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@ -1179,7 +1163,7 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
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if (mtu < IPV6_MIN_MTU)
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mtu = IPV6_MIN_MTU;
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dst_metric_set(dst, RTAX_MTU, mtu);
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rt6->rt6i_pmtu = mtu;
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rt6_update_expires(rt6, net->ipv6.sysctl.ip6_rt_mtu_expires);
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}
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}
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@ -1359,9 +1343,14 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst)
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static unsigned int ip6_mtu(const struct dst_entry *dst)
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{
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const struct rt6_info *rt = (const struct rt6_info *)dst;
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unsigned int mtu = rt->rt6i_pmtu;
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struct inet6_dev *idev;
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unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
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if (mtu)
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goto out;
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mtu = dst_metric_raw(dst, RTAX_MTU);
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if (mtu)
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goto out;
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@ -1947,11 +1936,26 @@ out:
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* Misc support functions
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*/
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static void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
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{
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BUG_ON(from->dst.from);
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rt->rt6i_flags &= ~RTF_EXPIRES;
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dst_hold(&from->dst);
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rt->dst.from = &from->dst;
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dst_init_metrics(&rt->dst, dst_metrics_ptr(&from->dst), true);
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}
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static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
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const struct in6_addr *dest)
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{
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struct net *net = dev_net(ort->dst.dev);
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struct rt6_info *rt = ip6_dst_alloc(net, ort->dst.dev, 0,
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struct rt6_info *rt;
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if (ort->rt6i_flags & RTF_CACHE)
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ort = (struct rt6_info *)ort->dst.from;
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rt = ip6_dst_alloc(net, ort->dst.dev, 0,
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ort->rt6i_table);
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if (rt) {
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@ -1961,7 +1965,6 @@ static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
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rt->rt6i_dst.addr = *dest;
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rt->rt6i_dst.plen = 128;
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dst_copy_metrics(&rt->dst, &ort->dst);
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rt->dst.error = ort->dst.error;
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rt->rt6i_idev = ort->rt6i_idev;
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if (rt->rt6i_idev)
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@ -2393,12 +2396,21 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg)
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PMTU discouvery.
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*/
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if (rt->dst.dev == arg->dev &&
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!dst_metric_locked(&rt->dst, RTAX_MTU) &&
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(dst_mtu(&rt->dst) >= arg->mtu ||
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!dst_metric_locked(&rt->dst, RTAX_MTU)) {
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if (rt->rt6i_flags & RTF_CACHE) {
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/* For RTF_CACHE with rt6i_pmtu == 0
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* (i.e. a redirected route),
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* the metrics of its rt->dst.from has already
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* been updated.
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*/
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if (rt->rt6i_pmtu && rt->rt6i_pmtu > arg->mtu)
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rt->rt6i_pmtu = arg->mtu;
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} else if (dst_mtu(&rt->dst) >= arg->mtu ||
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(dst_mtu(&rt->dst) < arg->mtu &&
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dst_mtu(&rt->dst) == idev->cnf.mtu6))) {
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dst_mtu(&rt->dst) == idev->cnf.mtu6)) {
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dst_metric_set(&rt->dst, RTAX_MTU, arg->mtu);
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}
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}
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return 0;
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}
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@ -2627,6 +2639,7 @@ static int rt6_fill_node(struct net *net,
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int iif, int type, u32 portid, u32 seq,
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int prefix, int nowait, unsigned int flags)
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{
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u32 metrics[RTAX_MAX];
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struct rtmsg *rtm;
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struct nlmsghdr *nlh;
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long expires;
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goto nla_put_failure;
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}
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if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
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memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
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if (rt->rt6i_pmtu)
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metrics[RTAX_MTU - 1] = rt->rt6i_pmtu;
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if (rtnetlink_put_metrics(skb, metrics) < 0)
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goto nla_put_failure;
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if (rt->rt6i_flags & RTF_GATEWAY) {
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