path: root/net/ipv4/devinet.c
diff options
authorShijie Luo <luoshijie1@huawei.com>2019-06-18 15:14:03 +0000
committerDavid S. Miller <davem@davemloft.net>2019-06-24 09:01:42 -0700
commitd8c444d540beaa39aff834c5b83df7e86a1ae765 (patch)
treed5f024393ace14a232f1d139215614f7a941569a /net/ipv4/devinet.c
parenttipc: remove the unnecessary msg->req check from tipc_nl_compat_bearer_set (diff)
ipv4: fix inet_select_addr() when enable route_localnet
Suppose we have two interfaces eth0 and eth1 in two hosts, follow the same steps in the two hosts: # sysctl -w net.ipv4.conf.eth1.route_localnet=1 # sysctl -w net.ipv4.conf.eth1.arp_announce=2 # ip route del dev lo table local and then set ip to eth1 in host1 like: # ifconfig eth1 set ip to eth2 in host2 and ping host1: # ifconfig eth1 # ping -I eth1 Well, host2 cannot connect to host1. When set a ip address with head 127, the scope of the address defaults to RT_SCOPE_HOST. In this situation, host2 will use arp_solicit() to send a arp request for the mac address of host1 with ip address When arp_announce=2, inet_select_addr() cannot select a correct saddr with condition ifa->ifa_scope > scope, because ifa_scope is RT_SCOPE_HOST and scope is RT_SCOPE_LINK. Then, inet_select_addr() will go to no_in_dev to lookup all interfaces to find a primary ip and finally get the primary ip of eth0. Here I add a localnet_scope defaults to RT_SCOPE_HOST, and when route_localnet is enabled, this value changes to RT_SCOPE_LINK to make inet_select_addr() find a correct primary ip as saddr of arp request. Fixes: d0daebc3d622 ("ipv4: Add interface option to enable routing of") Signed-off-by: Shijie Luo <luoshijie1@huawei.com> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/devinet.c')
1 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 914ccc7f192a..6fd4628d10b9 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1287,6 +1287,7 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
const struct in_ifaddr *ifa;
__be32 addr = 0;
+ unsigned char localnet_scope = RT_SCOPE_HOST;
struct in_device *in_dev;
struct net *net = dev_net(dev);
int master_idx;
@@ -1296,10 +1297,13 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
if (!in_dev)
goto no_in_dev;
+ if (unlikely(IN_DEV_ROUTE_LOCALNET(in_dev)))
+ localnet_scope = RT_SCOPE_LINK;
in_dev_for_each_ifa_rcu(ifa, in_dev) {
if (ifa->ifa_flags & IFA_F_SECONDARY)
- if (ifa->ifa_scope > scope)
+ if (min(ifa->ifa_scope, localnet_scope) > scope)
if (!dst || inet_ifa_match(dst, ifa)) {
addr = ifa->ifa_local;