diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | include/net/netns/ipv4.h | 3 | ||||
| -rw-r--r-- | net/ipv4/fib_semantics.c | 34 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 11 |
4 files changed, 53 insertions, 5 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index b183e2b606c8..6c7f365b1515 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -63,6 +63,16 @@ fwmark_reflect - BOOLEAN fwmark of the packet they are replying to. Default: 0 +fib_multipath_use_neigh - BOOLEAN + Use status of existing neighbor entry when determining nexthop for + multipath routes. If disabled, neighbor information is not used and + packets could be directed to a failed nexthop. Only valid for kernels + built with CONFIG_IP_ROUTE_MULTIPATH enabled. + Default: 0 (disabled) + Possible values: + 0 - disabled + 1 - enabled + route/max_size - INTEGER Maximum number of routes allowed in the kernel. Increase this when using large numbers of interfaces and/or routes. diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index a69cde3ce460..d061ffeb1e71 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -133,6 +133,9 @@ struct netns_ipv4 { struct fib_rules_ops *mr_rules_ops; #endif #endif +#ifdef CONFIG_IP_ROUTE_MULTIPATH + int sysctl_fib_multipath_use_neigh; +#endif atomic_t rt_genid; }; #endif diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index d97268e8ff10..ab64d9f2eef9 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -1559,21 +1559,45 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags) } #ifdef CONFIG_IP_ROUTE_MULTIPATH +static bool fib_good_nh(const struct fib_nh *nh) +{ + int state = NUD_REACHABLE; + + if (nh->nh_scope == RT_SCOPE_LINK) { + struct neighbour *n; + + rcu_read_lock_bh(); + + n = __ipv4_neigh_lookup_noref(nh->nh_dev, nh->nh_gw); + if (n) + state = n->nud_state; + + rcu_read_unlock_bh(); + } + + return !!(state & NUD_VALID); +} void fib_select_multipath(struct fib_result *res, int hash) { struct fib_info *fi = res->fi; + struct net *net = fi->fib_net; + bool first = false; for_nexthops(fi) { if (hash > atomic_read(&nh->nh_upper_bound)) continue; - res->nh_sel = nhsel; - return; + if (!net->ipv4.sysctl_fib_multipath_use_neigh || + fib_good_nh(nh)) { + res->nh_sel = nhsel; + return; + } + if (!first) { + res->nh_sel = nhsel; + first = true; + } } endfor_nexthops(fi); - - /* Race condition: route has just become dead. */ - res->nh_sel = 0; } #endif diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 1e1fe6086dd9..bb0419582b8d 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -960,6 +960,17 @@ static struct ctl_table ipv4_net_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, +#ifdef CONFIG_IP_ROUTE_MULTIPATH + { + .procname = "fib_multipath_use_neigh", + .data = &init_net.ipv4.sysctl_fib_multipath_use_neigh, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, +#endif { } }; |