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-rw-r--r--include/net/dst.h8
-rw-r--r--include/net/ip_fib.h10
-rw-r--r--net/core/dst.c23
-rw-r--r--net/ipv4/fib_semantics.c17
-rw-r--r--net/ipv4/route.c10
5 files changed, 45 insertions, 23 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
index 049af33da3b6..cfc043784166 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -107,10 +107,16 @@ struct dst_entry {
};
};
+struct dst_metrics {
+ u32 metrics[RTAX_MAX];
+ atomic_t refcnt;
+};
+extern const struct dst_metrics dst_default_metrics;
+
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
-extern const u32 dst_default_metrics[];
#define DST_METRICS_READ_ONLY 0x1UL
+#define DST_METRICS_REFCOUNTED 0x2UL
#define DST_METRICS_FLAGS 0x3UL
#define __DST_METRICS_PTR(Y) \
((u32 *)((Y) & ~DST_METRICS_FLAGS))
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 6692c5758b33..f7f6aa789c61 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -114,11 +114,11 @@ struct fib_info {
__be32 fib_prefsrc;
u32 fib_tb_id;
u32 fib_priority;
- u32 *fib_metrics;
-#define fib_mtu fib_metrics[RTAX_MTU-1]
-#define fib_window fib_metrics[RTAX_WINDOW-1]
-#define fib_rtt fib_metrics[RTAX_RTT-1]
-#define fib_advmss fib_metrics[RTAX_ADVMSS-1]
+ struct dst_metrics *fib_metrics;
+#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
+#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
+#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
+#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
int fib_nhs;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_weight;
diff --git a/net/core/dst.c b/net/core/dst.c
index 960e503b5a52..6192f11beec9 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -151,13 +151,13 @@ int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(dst_discard_out);
-const u32 dst_default_metrics[RTAX_MAX + 1] = {
+const struct dst_metrics dst_default_metrics = {
/* This initializer is needed to force linker to place this variable
* into const section. Otherwise it might end into bss section.
* We really want to avoid false sharing on this variable, and catch
* any writes on it.
*/
- [RTAX_MAX] = 0xdeadbeef,
+ .refcnt = ATOMIC_INIT(1),
};
void dst_init(struct dst_entry *dst, struct dst_ops *ops,
@@ -169,7 +169,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops,
if (dev)
dev_hold(dev);
dst->ops = ops;
- dst_init_metrics(dst, dst_default_metrics, true);
+ dst_init_metrics(dst, dst_default_metrics.metrics, true);
dst->expires = 0UL;
dst->path = dst;
dst->from = NULL;
@@ -314,25 +314,30 @@ EXPORT_SYMBOL(dst_release);
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
{
- u32 *p = kmalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
+ struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
if (p) {
- u32 *old_p = __DST_METRICS_PTR(old);
+ struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
unsigned long prev, new;
- memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
+ atomic_set(&p->refcnt, 1);
+ memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
new = (unsigned long) p;
prev = cmpxchg(&dst->_metrics, old, new);
if (prev != old) {
kfree(p);
- p = __DST_METRICS_PTR(prev);
+ p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
if (prev & DST_METRICS_READ_ONLY)
p = NULL;
+ } else if (prev & DST_METRICS_REFCOUNTED) {
+ if (atomic_dec_and_test(&old_p->refcnt))
+ kfree(old_p);
}
}
- return p;
+ BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
+ return (u32 *)p;
}
EXPORT_SYMBOL(dst_cow_metrics_generic);
@@ -341,7 +346,7 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
{
unsigned long prev, new;
- new = ((unsigned long) dst_default_metrics) | DST_METRICS_READ_ONLY;
+ new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
prev = cmpxchg(&dst->_metrics, old, new);
if (prev == old)
kfree(__DST_METRICS_PTR(old));
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index da449ddb8cc1..ad9ad4aab5da 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -203,6 +203,7 @@ static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
static void free_fib_info_rcu(struct rcu_head *head)
{
struct fib_info *fi = container_of(head, struct fib_info, rcu);
+ struct dst_metrics *m;
change_nexthops(fi) {
if (nexthop_nh->nh_dev)
@@ -213,8 +214,9 @@ static void free_fib_info_rcu(struct rcu_head *head)
rt_fibinfo_free(&nexthop_nh->nh_rth_input);
} endfor_nexthops(fi);
- if (fi->fib_metrics != (u32 *) dst_default_metrics)
- kfree(fi->fib_metrics);
+ m = fi->fib_metrics;
+ if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
+ kfree(m);
kfree(fi);
}
@@ -971,11 +973,11 @@ fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
val = 255;
if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
return -EINVAL;
- fi->fib_metrics[type - 1] = val;
+ fi->fib_metrics->metrics[type - 1] = val;
}
if (ecn_ca)
- fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
+ fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
return 0;
}
@@ -1033,11 +1035,12 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
goto failure;
fib_info_cnt++;
if (cfg->fc_mx) {
- fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
+ fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
if (!fi->fib_metrics)
goto failure;
+ atomic_set(&fi->fib_metrics->refcnt, 1);
} else
- fi->fib_metrics = (u32 *) dst_default_metrics;
+ fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
fi->fib_net = net;
fi->fib_protocol = cfg->fc_protocol;
@@ -1238,7 +1241,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
if (fi->fib_priority &&
nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
goto nla_put_failure;
- if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
+ if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
goto nla_put_failure;
if (fi->fib_prefsrc &&
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 655d9eebe43e..6883b3d4ba8f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1385,8 +1385,12 @@ static void rt_add_uncached_list(struct rtable *rt)
static void ipv4_dst_destroy(struct dst_entry *dst)
{
+ struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
struct rtable *rt = (struct rtable *) dst;
+ if (p != &dst_default_metrics && atomic_dec_and_test(&p->refcnt))
+ kfree(p);
+
if (!list_empty(&rt->rt_uncached)) {
struct uncached_list *ul = rt->rt_uncached_list;
@@ -1438,7 +1442,11 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
rt->rt_gateway = nh->nh_gw;
rt->rt_uses_gateway = 1;
}
- dst_init_metrics(&rt->dst, fi->fib_metrics, true);
+ dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
+ if (fi->fib_metrics != &dst_default_metrics) {
+ rt->dst._metrics |= DST_METRICS_REFCOUNTED;
+ atomic_inc(&fi->fib_metrics->refcnt);
+ }
#ifdef CONFIG_IP_ROUTE_CLASSID
rt->dst.tclassid = nh->nh_tclassid;
#endif
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.