[PATCH net-next 03/21] net: use loopback dev when generating blackhole route
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STALE3414d
SUPERSEDED: 1 (0M)
From: Wei Wang <hidden>
Date: 2017-06-16 17:48:22
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
Revision v1 of 2 in this series; 1 review trailer.
Revisions (2)
- v1 current
- v2 [diff vs current]
From: Wei Wang <redacted> Existing ipv4/6_blackhole_route() code generates a blackhole route with dst->dev pointing to the passed in dst->dev. It is not necessary to hold reference to the passed in dst->dev because the packets going through this route are dropped anyway. A loopback interface is good enough so that we don't need to worry about releasing this dst->dev when this dev is going down. Signed-off-by: Wei Wang <redacted> Acked-by: Martin KaFai Lau <redacted> --- net/ipv4/route.c | 2 +- net/ipv6/route.c | 9 +++++---- 2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9b38cf18144e..0a843ef2b709 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c@@ -2504,7 +2504,7 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or new->input = dst_discard; new->output = dst_discard_out; - new->dev = ort->dst.dev; + new->dev = net->loopback_dev; if (new->dev) dev_hold(new->dev);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 18fe6e2b88d5..bc1bc91bb969 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c@@ -1245,9 +1245,12 @@ EXPORT_SYMBOL_GPL(ip6_route_output_flags); struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_orig) { struct rt6_info *rt, *ort = (struct rt6_info *) dst_orig; + struct net_device *loopback_dev = net->loopback_dev; struct dst_entry *new = NULL; - rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, DST_OBSOLETE_NONE, 0); + + rt = dst_alloc(&ip6_dst_blackhole_ops, loopback_dev, 1, + DST_OBSOLETE_NONE, 0); if (rt) { rt6_info_init(rt);
@@ -1257,10 +1260,8 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori new->output = dst_discard_out; dst_copy_metrics(new, &ort->dst); - rt->rt6i_idev = ort->rt6i_idev; - if (rt->rt6i_idev) - in6_dev_hold(rt->rt6i_idev); + rt->rt6i_idev = in6_dev_get(loopback_dev); rt->rt6i_gateway = ort->rt6i_gateway; rt->rt6i_flags = ort->rt6i_flags & ~RTF_PCPU; rt->rt6i_metric = 0;
--
2.13.1.518.g3df882009-goog