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| author |   Paolo Abeni <pabeni@redhat.com> | 2017-09-28 15:51:37 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-10-01 03:55:47 +0100 |
| commit | bc044e8db7962e727a75b591b9851ff2ac5cf846 (patch) | |
| tree | e5cfa29af9e217039d26148e80b6b4546f39494f /net/ipv4/udp.c | |
| parent | IPv4: early demux can return an error code (diff) | |
| download | linux-dev-bc044e8db7962e727a75b591b9851ff2ac5cf846.tar.xz linux-dev-bc044e8db7962e727a75b591b9851ff2ac5cf846.zip | |
udp: perform source validation for mcast early demux
The UDP early demux can leverate the rx dst cache even for
multicast unconnected sockets.
In such scenario the ipv4 source address is validated only on
the first packet in the given flow. After that, when we fetch
the dst entry from the socket rx cache, we stop enforcing
the rp_filter and we even start accepting any kind of martian
addresses.
Disabling the dst cache for unconnected multicast socket will
cause large performace regression, nearly reducing by half the
max ingress tput.
Instead we factor out a route helper to completely validate an
skb source address for multicast packets and we call it from
the UDP early demux for mcast packets landing on unconnected
sockets, after successful fetching the related cached dst entry.
This still gives a measurable, but limited performance
regression:
rp_filter = 0 rp_filter = 1
edmux disabled: 1182 Kpps 1127 Kpps
edmux before: 2238 Kpps 2238 Kpps
edmux after: 2037 Kpps 2019 Kpps
The above figures are on top of current net tree.
Applying the net-next commit 6e617de84e87 ("net: avoid a full
fib lookup when rp_filter is disabled.") the delta with
rp_filter == 0 will decrease even more.
Fixes: 421b3885bf6d ("udp: ipv4: Add udp early demux")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 9b30f821fe96..5676237d2b0f 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2224,6 +2224,7 @@ static struct sock *__udp4_lib_demux_lookup(struct net *net, int udp_v4_early_demux(struct sk_buff *skb) { struct net *net = dev_net(skb->dev); + struct in_device *in_dev = NULL; const struct iphdr *iph; const struct udphdr *uh; struct sock *sk = NULL; @@ -2241,7 +2242,7 @@ int udp_v4_early_demux(struct sk_buff *skb) if (skb->pkt_type == PACKET_BROADCAST || skb->pkt_type == PACKET_MULTICAST) { - struct in_device *in_dev = __in_dev_get_rcu(skb->dev); + in_dev = __in_dev_get_rcu(skb->dev); if (!in_dev) return 0; @@ -2272,11 +2273,21 @@ int udp_v4_early_demux(struct sk_buff *skb) if (dst) dst = dst_check(dst, 0); if (dst) { + u32 itag = 0; + /* set noref for now. * any place which wants to hold dst has to call * dst_hold_safe() */ skb_dst_set_noref(skb, dst); + + /* for unconnected multicast sockets we need to validate + * the source on each packet + */ + if (!inet_sk(sk)->inet_daddr && in_dev) + return ip_mc_validate_source(skb, iph->daddr, + iph->saddr, iph->tos, + skb->dev, in_dev, &itag); } return 0; } |