net/ipv6: Defer initialization of dst to data path

Defer setting dst input, output and error until fib entry is copied.

The reject path from ip6_route_info_create is moved to a new function
ip6_rt_init_dst_reject with a helper doing the conversion from fib6_type
to dst error.

The remainder of the new ip6_rt_init_dst is an amalgamtion of dst code
from addrconf_dst_alloc and the non-reject path of ip6_route_info_create.
The dst output function is always ip6_output and the input function is
either ip6_input (local routes), ip6_mc_input (multicast routes) or
ip6_forward (anything else).

A couple of places using dst.error are updated to look at rt6i_flags.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 222af19d3403a022679faa99e89a3e49a5ed87dc..3b301aafd2ede053bf0083379c2d40e2f23d64a7 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -920,6 +920,75 @@ static struct net_device *ip6_rt_get_dev_rcu(struct rt6_info *rt)
        return dev;
 }
 
+static const int fib6_prop[RTN_MAX + 1] = {
+       [RTN_UNSPEC]    = 0,
+       [RTN_UNICAST]   = 0,
+       [RTN_LOCAL]     = 0,
+       [RTN_BROADCAST] = 0,
+       [RTN_ANYCAST]   = 0,
+       [RTN_MULTICAST] = 0,
+       [RTN_BLACKHOLE] = -EINVAL,
+       [RTN_UNREACHABLE] = -EHOSTUNREACH,
+       [RTN_PROHIBIT]  = -EACCES,
+       [RTN_THROW]     = -EAGAIN,
+       [RTN_NAT]       = -EINVAL,
+       [RTN_XRESOLVE]  = -EINVAL,
+};
+
+static int ip6_rt_type_to_error(u8 fib6_type)
+{
+       return fib6_prop[fib6_type];
+}
+
+static void ip6_rt_init_dst_reject(struct rt6_info *rt, struct rt6_info *ort)
+{
+       rt->dst.error = ip6_rt_type_to_error(ort->fib6_type);
+
+       switch (ort->fib6_type) {
+       case RTN_BLACKHOLE:
+               rt->dst.output = dst_discard_out;
+               rt->dst.input = dst_discard;
+               break;
+       case RTN_PROHIBIT:
+               rt->dst.output = ip6_pkt_prohibit_out;
+               rt->dst.input = ip6_pkt_prohibit;
+               break;
+       case RTN_THROW:
+       case RTN_UNREACHABLE:
+       default:
+               rt->dst.output = ip6_pkt_discard_out;
+               rt->dst.input = ip6_pkt_discard;
+               break;
+       }
+}
+
+static void ip6_rt_init_dst(struct rt6_info *rt, struct rt6_info *ort)
+{
+       if (ort->rt6i_flags & RTF_REJECT) {
+               ip6_rt_init_dst_reject(rt, ort);
+               return;
+       }
+
+       rt->dst.error = 0;
+       rt->dst.output = ip6_output;
+
+       if (ort->fib6_type == RTN_LOCAL) {
+               rt->dst.flags |= DST_HOST;
+               rt->dst.input = ip6_input;
+       } else if (ipv6_addr_type(&ort->rt6i_dst.addr) & IPV6_ADDR_MULTICAST) {
+               rt->dst.input = ip6_mc_input;
+       } else {
+               rt->dst.input = ip6_forward;
+       }
+
+       if (ort->fib6_nh.nh_lwtstate) {
+               rt->dst.lwtstate = lwtstate_get(ort->fib6_nh.nh_lwtstate);
+               lwtunnel_set_redirect(&rt->dst);
+       }
+
+       rt->dst.lastuse = jiffies;
+}
+
 static void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
 {
        BUG_ON(from->from);
@@ -932,14 +1001,12 @@ static void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
 
 static void ip6_rt_copy_init(struct rt6_info *rt, struct rt6_info *ort)
 {
-       rt->dst.input = ort->dst.input;
-       rt->dst.output = ort->dst.output;
+       ip6_rt_init_dst(rt, ort);
+
        rt->rt6i_dst = ort->rt6i_dst;
-       rt->dst.error = ort->dst.error;
        rt->rt6i_idev = ort->rt6i_idev;
        if (rt->rt6i_idev)
                in6_dev_hold(rt->rt6i_idev);
-       rt->dst.lastuse = jiffies;
        rt->rt6i_gateway = ort->fib6_nh.nh_gw;
        rt->rt6i_flags = ort->rt6i_flags;
        rt6_set_from(rt, ort);
@@ -2329,7 +2396,7 @@ restart:
                        continue;
                if (rt6_check_expired(rt))
                        continue;
-               if (rt->dst.error)
+               if (rt->rt6i_flags & RTF_REJECT)
                        break;
                if (!(rt->rt6i_flags & RTF_GATEWAY))
                        continue;
@@ -2357,7 +2424,7 @@ restart:
 
        if (!rt)
                rt = net->ipv6.ip6_null_entry;
-       else if (rt->dst.error) {
+       else if (rt->rt6i_flags & RTF_REJECT) {
                rt = net->ipv6.ip6_null_entry;
                goto out;
        }
@@ -2900,15 +2967,6 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
 
        addr_type = ipv6_addr_type(&cfg->fc_dst);
 
-       if (addr_type & IPV6_ADDR_MULTICAST)
-               rt->dst.input = ip6_mc_input;
-       else if (cfg->fc_flags & RTF_LOCAL)
-               rt->dst.input = ip6_input;
-       else
-               rt->dst.input = ip6_forward;
-
-       rt->dst.output = ip6_output;
-
        if (cfg->fc_encap) {
                struct lwtunnel_state *lwtstate;
 
@@ -2918,7 +2976,6 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                if (err)
                        goto out;
                rt->fib6_nh.nh_lwtstate = lwtstate_get(lwtstate);
-               lwtunnel_set_redirect(&rt->dst);
        }
 
        ipv6_addr_prefix(&rt->rt6i_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);
@@ -2958,27 +3015,6 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                        }
                }
                rt->rt6i_flags = RTF_REJECT|RTF_NONEXTHOP;
-               switch (cfg->fc_type) {
-               case RTN_BLACKHOLE:
-                       rt->dst.error = -EINVAL;
-                       rt->dst.output = dst_discard_out;
-                       rt->dst.input = dst_discard;
-                       break;
-               case RTN_PROHIBIT:
-                       rt->dst.error = -EACCES;
-                       rt->dst.output = ip6_pkt_prohibit_out;
-                       rt->dst.input = ip6_pkt_prohibit;
-                       break;
-               case RTN_THROW:
-               case RTN_UNREACHABLE:
-               default:
-                       rt->dst.error = (cfg->fc_type == RTN_THROW) ? -EAGAIN
-                                       : (cfg->fc_type == RTN_UNREACHABLE)
-                                       ? -EHOSTUNREACH : -ENETUNREACH;
-                       rt->dst.output = ip6_pkt_discard_out;
-                       rt->dst.input = ip6_pkt_discard;
-                       break;
-               }
                goto install_route;
        }
 
@@ -3623,12 +3659,9 @@ struct rt6_info *addrconf_dst_alloc(struct net *net,
                return ERR_PTR(-ENOMEM);
 
        in6_dev_hold(idev);
-
-       rt->dst.flags |= DST_HOST;
-       rt->dst.input = ip6_input;
-       rt->dst.output = ip6_output;
        rt->rt6i_idev = idev;
 
+       rt->dst.flags |= DST_HOST;
        rt->rt6i_protocol = RTPROT_KERNEL;
        rt->rt6i_flags = RTF_UP | RTF_NONEXTHOP;
        if (anycast) {