net: Loopback ifindex is constant now

As pointed out, there are places, that access net->loopback_dev->ifindex
and after ifindex generation is made per-net this value becomes constant
equals 1. So go ahead and introduce the LOOPBACK_IFINDEX constant and use
it where appropriate.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index e2a06fd996d51409ed711fb360105d7f423f27a8..4a075babe1937b9d9b4cc98b18360b181acfdb56 100644 (file)
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -197,6 +197,7 @@ static __net_init int loopback_net_init(struct net *net)
        if (err)
                goto out_free_netdev;
 
+       BUG_ON(dev->ifindex != LOOPBACK_IFINDEX);
        net->loopback_dev = dev;
        return 0;
 

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 6dc3db3466bfb68b64e0e2643ca4088b0007e3b7..97e441945c13a90a67aabc90225cd412d85eacb1 100644 (file)
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -105,6 +105,13 @@ struct net {
        struct sock             *diag_nlsk;
 };
 
+/*
+ * ifindex generation is per-net namespace, and loopback is
+ * always the 1st device in ns (see net_dev_init), thus any
+ * loopback device should get ifindex 1
+ */
+
+#define LOOPBACK_IFINDEX       1
 
 #include <linux/seq_file_net.h>
 

diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 85a3604c87c8d2cac6cac4d7049d9ba75877bf66..c855e8d0738f75a08a1d44a35a02ff870132510f 100644 (file)
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -961,7 +961,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *o
                .saddr = oldflp->saddr,
                .flowidn_scope = RT_SCOPE_UNIVERSE,
                .flowidn_mark = oldflp->flowidn_mark,
-               .flowidn_iif = init_net.loopback_dev->ifindex,
+               .flowidn_iif = LOOPBACK_IFINDEX,
                .flowidn_oif = oldflp->flowidn_oif,
        };
        struct dn_route *rt = NULL;
@@ -979,7 +979,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *o
                       "dn_route_output_slow: dst=%04x src=%04x mark=%d"
                       " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
                       le16_to_cpu(oldflp->saddr),
-                      oldflp->flowidn_mark, init_net.loopback_dev->ifindex,
+                      oldflp->flowidn_mark, LOOPBACK_IFINDEX,
                       oldflp->flowidn_oif);
 
        /* If we have an output interface, verify its a DECnet device */
@@ -1042,7 +1042,7 @@ source_ok:
                        if (!fld.daddr)
                                goto out;
                }
-               fld.flowidn_oif = init_net.loopback_dev->ifindex;
+               fld.flowidn_oif = LOOPBACK_IFINDEX;
                res.type = RTN_LOCAL;
                goto make_route;
        }

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index c43ae3fba7921e590859cea407ba9b9e030b16be..7f073a38c87d88a89f2c11d3cd56b67a66d194b2 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -218,7 +218,7 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb)
        scope = RT_SCOPE_UNIVERSE;
        if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
                fl4.flowi4_oif = 0;
-               fl4.flowi4_iif = net->loopback_dev->ifindex;
+               fl4.flowi4_iif = LOOPBACK_IFINDEX;
                fl4.daddr = ip_hdr(skb)->saddr;
                fl4.saddr = 0;
                fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 8eec8f4a05360d24897719495100ea100f0c69b2..3a57570c8ee5ecf8570cb9fb714664d2a262d211 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1798,7 +1798,7 @@ static struct mr_table *ipmr_rt_fib_lookup(struct net *net, struct sk_buff *skb)
                .flowi4_oif = (rt_is_output_route(rt) ?
                               skb->dev->ifindex : 0),
                .flowi4_iif = (rt_is_output_route(rt) ?
-                              net->loopback_dev->ifindex :
+                              LOOPBACK_IFINDEX :
                               skb->dev->ifindex),
                .flowi4_mark = skb->mark,
        };

diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c
index 31371be8174be1d8da1a50f11dd6c48409b29b74..c30130062cd6515f31d7497eaa6a403d2b1d629d 100644 (file)
--- a/net/ipv4/netfilter/ipt_rpfilter.c
+++ b/net/ipv4/netfilter/ipt_rpfilter.c
@@ -85,7 +85,7 @@ static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par)
                        return ipv4_is_local_multicast(iph->daddr) ^ invert;
                flow.flowi4_iif = 0;
        } else {
-               flow.flowi4_iif = dev_net(par->in)->loopback_dev->ifindex;
+               flow.flowi4_iif = LOOPBACK_IFINDEX;
        }
 
        flow.daddr = iph->saddr;

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 21ad369014c0308e85952127203ad15f84a2a2c9..c58137391a3dd2a8b317deb16aa0420b37c93c80 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1619,7 +1619,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 
        if (res.type == RTN_LOCAL) {
                err = fib_validate_source(skb, saddr, daddr, tos,
-                                         net->loopback_dev->ifindex,
+                                         LOOPBACK_IFINDEX,
                                          dev, in_dev, &itag);
                if (err < 0)
                        goto martian_source_keep_err;
@@ -1895,7 +1895,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
 
        orig_oif = fl4->flowi4_oif;
 
-       fl4->flowi4_iif = net->loopback_dev->ifindex;
+       fl4->flowi4_iif = LOOPBACK_IFINDEX;
        fl4->flowi4_tos = tos & IPTOS_RT_MASK;
        fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
                         RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
@@ -1984,7 +1984,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
                if (!fl4->daddr)
                        fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
                dev_out = net->loopback_dev;
-               fl4->flowi4_oif = net->loopback_dev->ifindex;
+               fl4->flowi4_oif = LOOPBACK_IFINDEX;
                res.type = RTN_LOCAL;
                flags |= RTCF_LOCAL;
                goto make_route;

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 8e80fd279100d7d18d111eff1be73f10fdd6eeaf..0ddf2d132e7f0840bcf327d4d0149fe2136fe943 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -965,7 +965,7 @@ struct dst_entry * ip6_route_output(struct net *net, const struct sock *sk,
 {
        int flags = 0;
 
-       fl6->flowi6_iif = net->loopback_dev->ifindex;
+       fl6->flowi6_iif = LOOPBACK_IFINDEX;
 
        if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr))
                flags |= RT6_LOOKUP_F_IFACE;