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Message-Id: <20140326154245.10C6CE6E05@unicorn.suse.cz>
Date: Wed, 26 Mar 2014 16:42:45 +0100 (CET)
From: Michal Kubecek <mkubecek@...e.cz>
To: "David S. Miller" <davem@...emloft.net>
Cc: Hannes Frederic Sowa <hannes@...essinduktion.org>,
netdev@...r.kernel.org, Alexey Kuznetsov <kuznet@....inr.ac.ru>,
James Morris <jmorris@...ei.org>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Patrick McHardy <kaber@...sh.net>
Subject: [PATCH net-next v3] ipv6: do not overwrite inetpeer metrics
prematurely
If an IPv6 host route with metrics exists, an attempt to add a
new route for the same target with different metrics fails but
rewrites the metrics anyway:
12sp0:~ # ip route add fec0::1 dev eth0 rto_min 1000
12sp0:~ # ip -6 route show
fe80::/64 dev eth0 proto kernel metric 256
fec0::1 dev eth0 metric 1024 rto_min lock 1s
12sp0:~ # ip route add fec0::1 dev eth0 rto_min 1500
RTNETLINK answers: File exists
12sp0:~ # ip -6 route show
fe80::/64 dev eth0 proto kernel metric 256
fec0::1 dev eth0 metric 1024 rto_min lock 1.5s
This is caused by all IPv6 host routes using the metrics in
their inetpeer (or the shared default). This also holds for the
new route created in ip6_route_add() which shares the metrics
with the already existing route and thus ip6_route_add()
rewrites the metrics even if the new route ends up not being
used at all.
Another problem is that old metrics in inetpeer can reappear
unexpectedly for a new route, e.g.
12sp0:~ # ip route add fec0::1 dev eth0 rto_min 1000
12sp0:~ # ip route del fec0::1
12sp0:~ # ip route add fec0::1 dev eth0
12sp0:~ # ip route change fec0::1 dev eth0 hoplimit 10
12sp0:~ # ip -6 route show
fe80::/64 dev eth0 proto kernel metric 256
fec0::1 dev eth0 metric 1024 hoplimit 10 rto_min lock 1s
Resolve the first problem by moving the setting of metrics down
into fib6_add_rt2node() to the point we are sure we are
inserting the new route into the tree. Second problem is
addressed by introducing new flag DST_KEEP_METRICS which is set
for a new host route in ip6_route_add() and makes
ipv6_cow_metrics() always overwrite the metrics in inetpeer
(even if they are not "new"); it is reset after that.
v3: rewritten based on David Miller's idea to move setting the
metrics (and allocation in non-host case) down to the point we
already know the route is to be inserted. Also rebased to
net-next as it is quite late in the cycle.
Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
---
include/net/dst.h | 1 +
include/net/ip6_fib.h | 3 ++-
net/ipv6/ip6_fib.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
net/ipv6/route.c | 41 +++++++++--------------------------------
4 files changed, 56 insertions(+), 36 deletions(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index e01a826..8cf6772 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -57,6 +57,7 @@ struct dst_entry {
#define DST_FAKE_RTABLE 0x0040
#define DST_XFRM_TUNNEL 0x0080
#define DST_XFRM_QUEUE 0x0100
+#define DST_KEEP_METRICS 0x0400
unsigned short pending_confirm;
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index aca0c27..9bcb220 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -284,7 +284,8 @@ struct fib6_node *fib6_locate(struct fib6_node *root,
void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
void *arg);
-int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info);
+int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
+ struct nlattr *mx, int mx_len);
int fib6_del(struct rt6_info *rt, struct nl_info *info);
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 075602f..4ee487b 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -638,12 +638,41 @@ static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
RTF_GATEWAY;
}
+static int fib6_commit_metrics(struct dst_entry *dst,
+ struct nlattr *mx, int mx_len)
+{
+ struct nlattr *nla;
+ int remaining;
+ u32 *mp;
+
+ if (dst->flags & DST_HOST) {
+ mp = dst_metrics_write_ptr(dst);
+ } else {
+ mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
+ if (!mp)
+ return -ENOMEM;
+ dst_init_metrics(dst, mp, 0);
+ }
+
+ nla_for_each_attr(nla, mx, mx_len, remaining) {
+ int type = nla_type(nla);
+
+ if (type) {
+ if (type > RTAX_MAX)
+ return -EINVAL;
+
+ mp[type - 1] = nla_get_u32(nla);
+ }
+ }
+ return 0;
+}
+
/*
* Insert routing information in a node.
*/
static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
- struct nl_info *info)
+ struct nl_info *info, struct nlattr *mx, int mx_len)
{
struct rt6_info *iter = NULL;
struct rt6_info **ins;
@@ -653,6 +682,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
(info->nlh->nlmsg_flags & NLM_F_CREATE));
int found = 0;
bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
+ int err;
ins = &fn->leaf;
@@ -751,6 +781,11 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
pr_warn("NLM_F_CREATE should be set when creating new route\n");
add:
+ if (mx) {
+ err = fib6_commit_metrics(&rt->dst, mx, mx_len);
+ if (err)
+ return err;
+ }
rt->dst.rt6_next = iter;
*ins = rt;
rt->rt6i_node = fn;
@@ -770,6 +805,11 @@ add:
pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
return -ENOENT;
}
+ if (mx) {
+ err = fib6_commit_metrics(&rt->dst, mx, mx_len);
+ if (err)
+ return err;
+ }
*ins = rt;
rt->rt6i_node = fn;
rt->dst.rt6_next = iter->dst.rt6_next;
@@ -806,7 +846,8 @@ void fib6_force_start_gc(struct net *net)
* with source addr info in sub-trees
*/
-int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
+int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
+ struct nlattr *mx, int mx_len)
{
struct fib6_node *fn, *pn = NULL;
int err = -ENOMEM;
@@ -900,7 +941,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
}
#endif
- err = fib6_add_rt2node(fn, rt, info);
+ err = fib6_add_rt2node(fn, rt, info, mx, mx_len);
if (!err) {
fib6_start_gc(info->nl_net, rt);
if (!(rt->rt6i_flags & RTF_CACHE))
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index fba54a4..b6dda6a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -149,8 +149,10 @@ static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old)
unsigned long prev, new;
p = peer->metrics;
- if (inet_metrics_new(peer))
+ if (inet_metrics_new(peer) || (dst->flags | DST_KEEP_METRICS)) {
memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
+ dst->flags &= ~DST_KEEP_METRICS;
+ }
new = (unsigned long) p;
prev = cmpxchg(&dst->_metrics, old, new);
@@ -857,14 +859,15 @@ EXPORT_SYMBOL(rt6_lookup);
be destroyed.
*/
-static int __ip6_ins_rt(struct rt6_info *rt, struct nl_info *info)
+static int __ip6_ins_rt(struct rt6_info *rt, struct nl_info *info,
+ struct nlattr *mx, int mx_len)
{
int err;
struct fib6_table *table;
table = rt->rt6i_table;
write_lock_bh(&table->tb6_lock);
- err = fib6_add(&table->tb6_root, rt, info);
+ err = fib6_add(&table->tb6_root, rt, info, mx, mx_len);
write_unlock_bh(&table->tb6_lock);
return err;
@@ -875,7 +878,7 @@ int ip6_ins_rt(struct rt6_info *rt)
struct nl_info info = {
.nl_net = dev_net(rt->dst.dev),
};
- return __ip6_ins_rt(rt, &info);
+ return __ip6_ins_rt(rt, &info, NULL, 0);
}
static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
@@ -1544,16 +1547,8 @@ int ip6_route_add(struct fib6_config *cfg)
ipv6_addr_prefix(&rt->rt6i_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);
rt->rt6i_dst.plen = cfg->fc_dst_len;
if (rt->rt6i_dst.plen == 128)
- rt->dst.flags |= DST_HOST;
+ rt->dst.flags |= DST_HOST | DST_KEEP_METRICS;
- if (!(rt->dst.flags & DST_HOST) && cfg->fc_mx) {
- u32 *metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
- if (!metrics) {
- err = -ENOMEM;
- goto out;
- }
- dst_init_metrics(&rt->dst, metrics, 0);
- }
#ifdef CONFIG_IPV6_SUBTREES
ipv6_addr_prefix(&rt->rt6i_src.addr, &cfg->fc_src, cfg->fc_src_len);
rt->rt6i_src.plen = cfg->fc_src_len;
@@ -1672,31 +1667,13 @@ int ip6_route_add(struct fib6_config *cfg)
rt->rt6i_flags = cfg->fc_flags;
install_route:
- if (cfg->fc_mx) {
- struct nlattr *nla;
- int remaining;
-
- nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
- int type = nla_type(nla);
-
- if (type) {
- if (type > RTAX_MAX) {
- err = -EINVAL;
- goto out;
- }
-
- dst_metric_set(&rt->dst, type, nla_get_u32(nla));
- }
- }
- }
-
rt->dst.dev = dev;
rt->rt6i_idev = idev;
rt->rt6i_table = table;
cfg->fc_nlinfo.nl_net = dev_net(dev);
- return __ip6_ins_rt(rt, &cfg->fc_nlinfo);
+ return __ip6_ins_rt(rt, &cfg->fc_nlinfo, cfg->fc_mx, cfg->fc_mx_len);
out:
if (dev)
--
1.8.1.4
--
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