From 8c298120f96d72fb1f2f4efd4fc3d911c92f6d3f Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 22 Mar 2011 21:56:23 -0700 Subject: [PATCH] ipv4: Fallback to FIB local table in __ip_dev_find(). In commit f6d2567473d5874739a7ff7a93a01f24ee03f535 ("ipv4: Implement __ip_dev_find using new interface address hash.") we reimplemented __ip_dev_find() so that it doesn't have to do a full FIB table lookup. Instead, it consults a hash table of addresses configured to interfaces. This works identically to the old code in all except one case, and that is for loopback subnets. The old code would match the loopback device for any IP address that falls within a subnet configured to the loopback device. Handle this corner case by doing the FIB lookup. We could implement this via inet_addr_onlink() but: 1) Someone could configure many addresses to loopback and inet_addr_onlink() is a simple list traversal. 2) We know the old code works. Reported-by: Julian Anastasov Acked-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index d5a4553bebc3f..5345b0bee6df8 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -64,6 +64,8 @@ #include #include +#include "fib_lookup.h" + static struct ipv4_devconf ipv4_devconf = { .data = { [IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1, @@ -151,6 +153,20 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref) break; } } + if (!result) { + struct flowi4 fl4 = { .daddr = addr }; + struct fib_result res = { 0 }; + struct fib_table *local; + + /* Fallback to FIB local table so that communication + * over loopback subnets work. + */ + local = fib_get_table(net, RT_TABLE_LOCAL); + if (local && + !fib_table_lookup(local, &fl4, &res, FIB_LOOKUP_NOREF) && + res.type == RTN_LOCAL) + result = FIB_RES_DEV(res); + } if (result && devref) dev_hold(result); rcu_read_unlock(); -- 2.39.5