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-rw-r--r--include/net/ip_fib.h14
-rw-r--r--include/net/route.h11
-rw-r--r--net/ipv4/fib_semantics.c140
-rw-r--r--net/ipv4/icmp.c19
-rw-r--r--net/ipv4/route.c65
5 files changed, 173 insertions, 76 deletions
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 727d6e9a9685..7a51fd8d99e4 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -79,7 +79,7 @@ struct fib_nh {
unsigned char nh_scope;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int nh_weight;
- int nh_power;
+ atomic_t nh_upper_bound;
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
__u32 nh_tclassid;
@@ -118,7 +118,7 @@ struct fib_info {
#define fib_advmss fib_metrics[RTAX_ADVMSS-1]
int fib_nhs;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- int fib_power;
+ int fib_weight;
#endif
struct rcu_head rcu;
struct fib_nh fib_nh[0];
@@ -320,7 +320,15 @@ int ip_fib_check_default(__be32 gw, struct net_device *dev);
int fib_sync_down_dev(struct net_device *dev, unsigned long event);
int fib_sync_down_addr(struct net *net, __be32 local);
int fib_sync_up(struct net_device *dev, unsigned int nh_flags);
-void fib_select_multipath(struct fib_result *res);
+
+extern u32 fib_multipath_secret __read_mostly;
+
+static inline int fib_multipath_hash(__be32 saddr, __be32 daddr)
+{
+ return jhash_2words(saddr, daddr, fib_multipath_secret) >> 1;
+}
+
+void fib_select_multipath(struct fib_result *res, int hash);
/* Exported by fib_trie.c */
void fib_trie_init(void);
diff --git a/include/net/route.h b/include/net/route.h
index e211dc167db1..d32cb76f5302 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -28,6 +28,7 @@
#include <net/inetpeer.h>
#include <net/flow.h>
#include <net/inet_sock.h>
+#include <net/ip_fib.h>
#include <net/l3mdev.h>
#include <linux/in_route.h>
#include <linux/rtnetlink.h>
@@ -113,7 +114,15 @@ struct in_device;
int ip_rt_init(void);
void rt_cache_flush(struct net *net);
void rt_flush_dev(struct net_device *dev);
-struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
+struct rtable *__ip_route_output_key_hash(struct net *, struct flowi4 *flp,
+ int mp_hash);
+
+static inline struct rtable *__ip_route_output_key(struct net *net,
+ struct flowi4 *flp)
+{
+ return __ip_route_output_key_hash(net, flp, -1);
+}
+
struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
const struct sock *sk);
struct dst_entry *ipv4_blackhole_route(struct net *net,
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 064bd3caaa4f..0c49d2f3bbc0 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -57,8 +57,7 @@ static unsigned int fib_info_cnt;
static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
#ifdef CONFIG_IP_ROUTE_MULTIPATH
-
-static DEFINE_SPINLOCK(fib_multipath_lock);
+u32 fib_multipath_secret __read_mostly;
#define for_nexthops(fi) { \
int nhsel; const struct fib_nh *nh; \
@@ -532,7 +531,67 @@ errout:
return ret;
}
-#endif
+static void fib_rebalance(struct fib_info *fi)
+{
+ int total;
+ int w;
+ struct in_device *in_dev;
+
+ if (fi->fib_nhs < 2)
+ return;
+
+ total = 0;
+ for_nexthops(fi) {
+ if (nh->nh_flags & RTNH_F_DEAD)
+ continue;
+
+ in_dev = __in_dev_get_rcu(nh->nh_dev);
+
+ if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ nh->nh_flags & RTNH_F_LINKDOWN)
+ continue;
+
+ total += nh->nh_weight;
+ } endfor_nexthops(fi);
+
+ w = 0;
+ change_nexthops(fi) {
+ int upper_bound;
+
+ in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev);
+
+ if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
+ upper_bound = -1;
+ } else if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
+ upper_bound = -1;
+ } else {
+ w += nexthop_nh->nh_weight;
+ upper_bound = DIV_ROUND_CLOSEST(2147483648LL * w,
+ total) - 1;
+ }
+
+ atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
+ } endfor_nexthops(fi);
+
+ net_get_random_once(&fib_multipath_secret,
+ sizeof(fib_multipath_secret));
+}
+
+static inline void fib_add_weight(struct fib_info *fi,
+ const struct fib_nh *nh)
+{
+ fi->fib_weight += nh->nh_weight;
+}
+
+#else /* CONFIG_IP_ROUTE_MULTIPATH */
+
+#define fib_rebalance(fi) do { } while (0)
+#define fib_add_weight(fi, nh) do { } while (0)
+
+#endif /* CONFIG_IP_ROUTE_MULTIPATH */
static int fib_encap_match(struct net *net, u16 encap_type,
struct nlattr *encap,
@@ -1094,8 +1153,11 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
change_nexthops(fi) {
fib_info_update_nh_saddr(net, nexthop_nh);
+ fib_add_weight(fi, nexthop_nh);
} endfor_nexthops(fi)
+ fib_rebalance(fi);
+
link_it:
ofi = fib_find_info(fi);
if (ofi) {
@@ -1317,12 +1379,6 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event)
nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
break;
}
-#ifdef CONFIG_IP_ROUTE_MULTIPATH
- spin_lock_bh(&fib_multipath_lock);
- fi->fib_power -= nexthop_nh->nh_power;
- nexthop_nh->nh_power = 0;
- spin_unlock_bh(&fib_multipath_lock);
-#endif
dead++;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
@@ -1345,6 +1401,8 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event)
}
ret++;
}
+
+ fib_rebalance(fi);
}
return ret;
@@ -1467,20 +1525,15 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
!__in_dev_get_rtnl(dev))
continue;
alive++;
-#ifdef CONFIG_IP_ROUTE_MULTIPATH
- spin_lock_bh(&fib_multipath_lock);
- nexthop_nh->nh_power = 0;
- nexthop_nh->nh_flags &= ~nh_flags;
- spin_unlock_bh(&fib_multipath_lock);
-#else
nexthop_nh->nh_flags &= ~nh_flags;
-#endif
} endfor_nexthops(fi)
if (alive > 0) {
fi->fib_flags &= ~nh_flags;
ret++;
}
+
+ fib_rebalance(fi);
}
return ret;
@@ -1488,62 +1541,19 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
#ifdef CONFIG_IP_ROUTE_MULTIPATH
-/*
- * The algorithm is suboptimal, but it provides really
- * fair weighted route distribution.
- */
-void fib_select_multipath(struct fib_result *res)
+void fib_select_multipath(struct fib_result *res, int hash)
{
struct fib_info *fi = res->fi;
- struct in_device *in_dev;
- int w;
-
- spin_lock_bh(&fib_multipath_lock);
- if (fi->fib_power <= 0) {
- int power = 0;
- change_nexthops(fi) {
- in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev);
- if (nexthop_nh->nh_flags & RTNH_F_DEAD)
- continue;
- if (in_dev &&
- IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
- nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
- continue;
- power += nexthop_nh->nh_weight;
- nexthop_nh->nh_power = nexthop_nh->nh_weight;
- } endfor_nexthops(fi);
- fi->fib_power = power;
- if (power <= 0) {
- spin_unlock_bh(&fib_multipath_lock);
- /* Race condition: route has just become dead. */
- res->nh_sel = 0;
- return;
- }
- }
-
- /* w should be random number [0..fi->fib_power-1],
- * it is pretty bad approximation.
- */
-
- w = jiffies % fi->fib_power;
+ for_nexthops(fi) {
+ if (hash > atomic_read(&nh->nh_upper_bound))
+ continue;
- change_nexthops(fi) {
- if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
- nexthop_nh->nh_power) {
- w -= nexthop_nh->nh_power;
- if (w <= 0) {
- nexthop_nh->nh_power--;
- fi->fib_power--;
- res->nh_sel = nhsel;
- spin_unlock_bh(&fib_multipath_lock);
- return;
- }
- }
+ res->nh_sel = nhsel;
+ return;
} endfor_nexthops(fi);
/* Race condition: route has just become dead. */
res->nh_sel = 0;
- spin_unlock_bh(&fib_multipath_lock);
}
#endif
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 6b96dee2800b..36e26977c908 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -440,6 +440,22 @@ out_unlock:
icmp_xmit_unlock(sk);
}
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+
+/* Source and destination is swapped. See ip_multipath_icmp_hash */
+static int icmp_multipath_hash_skb(const struct sk_buff *skb)
+{
+ const struct iphdr *iph = ip_hdr(skb);
+
+ return fib_multipath_hash(iph->daddr, iph->saddr);
+}
+
+#else
+
+#define icmp_multipath_hash_skb(skb) (-1)
+
+#endif
+
static struct rtable *icmp_route_lookup(struct net *net,
struct flowi4 *fl4,
struct sk_buff *skb_in,
@@ -464,7 +480,8 @@ static struct rtable *icmp_route_lookup(struct net *net,
fl4->flowi4_oif = l3mdev_master_ifindex(skb_in->dev);
security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));
- rt = __ip_route_output_key(net, fl4);
+ rt = __ip_route_output_key_hash(net, fl4,
+ icmp_multipath_hash_skb(skb_in));
if (IS_ERR(rt))
return rt;
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 76ca4e75f785..54297d3a0559 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1651,6 +1651,48 @@ out:
return err;
}
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+
+/* To make ICMP packets follow the right flow, the multipath hash is
+ * calculated from the inner IP addresses in reverse order.
+ */
+static int ip_multipath_icmp_hash(struct sk_buff *skb)
+{
+ const struct iphdr *outer_iph = ip_hdr(skb);
+ struct icmphdr _icmph;
+ const struct icmphdr *icmph;
+ struct iphdr _inner_iph;
+ const struct iphdr *inner_iph;
+
+ if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
+ goto standard_hash;
+
+ icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
+ &_icmph);
+ if (!icmph)
+ goto standard_hash;
+
+ if (icmph->type != ICMP_DEST_UNREACH &&
+ icmph->type != ICMP_REDIRECT &&
+ icmph->type != ICMP_TIME_EXCEEDED &&
+ icmph->type != ICMP_PARAMETERPROB) {
+ goto standard_hash;
+ }
+
+ inner_iph = skb_header_pointer(skb,
+ outer_iph->ihl * 4 + sizeof(_icmph),
+ sizeof(_inner_iph), &_inner_iph);
+ if (!inner_iph)
+ goto standard_hash;
+
+ return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
+
+standard_hash:
+ return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
+}
+
+#endif /* CONFIG_IP_ROUTE_MULTIPATH */
+
static int ip_mkroute_input(struct sk_buff *skb,
struct fib_result *res,
const struct flowi4 *fl4,
@@ -1658,8 +1700,15 @@ static int ip_mkroute_input(struct sk_buff *skb,
__be32 daddr, __be32 saddr, u32 tos)
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (res->fi && res->fi->fib_nhs > 1)
- fib_select_multipath(res);
+ if (res->fi && res->fi->fib_nhs > 1) {
+ int h;
+
+ if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
+ h = ip_multipath_icmp_hash(skb);
+ else
+ h = fib_multipath_hash(saddr, daddr);
+ fib_select_multipath(res, h);
+ }
#endif
/* create a routing cache entry */
@@ -2026,7 +2075,8 @@ add:
* Major route resolver routine.
*/
-struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
+struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
+ int mp_hash)
{
struct net_device *dev_out = NULL;
__u8 tos = RT_FL_TOS(fl4);
@@ -2189,8 +2239,11 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
- fib_select_multipath(&res);
+ if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
+ if (mp_hash < 0)
+ mp_hash = fib_multipath_hash(fl4->saddr, fl4->daddr);
+ fib_select_multipath(&res, mp_hash);
+ }
else
#endif
if (!res.prefixlen &&
@@ -2212,7 +2265,7 @@ out:
rcu_read_unlock();
return rth;
}
-EXPORT_SYMBOL_GPL(__ip_route_output_key);
+EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
{
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