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IPv4: early demux can return an error code

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Currently no error is emitted, but this infrastructure will
used by the next patch to allow source address validation
for mcast sockets.
Since early demux can do a route lookup and an ipv4 route
lookup can return an error code this is consistent with the
current ipv4 route infrastructure.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2017-09-28 15:51:36 +02:00 committed by David S. Miller
parent d41bb33ba3
commit 7487449c86
6 changed files with 30 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/protocol.h
View File

@ -39,8 +39,8 @@
/* This is used to register protocols. */
struct net_protocol {
void (*early_demux)(struct sk_buff *skb);
void (*early_demux_handler)(struct sk_buff *skb);
int (*early_demux)(struct sk_buff *skb);
int (*early_demux_handler)(struct sk_buff *skb);
int (*handler)(struct sk_buff *skb);
void (*err_handler)(struct sk_buff *skb, u32 info);
unsigned int no_policy:1,

2
include/net/tcp.h
View File

@ -345,7 +345,7 @@ void tcp_v4_err(struct sk_buff *skb, u32);
void tcp_shutdown(struct sock *sk, int how);
void tcp_v4_early_demux(struct sk_buff *skb);
int tcp_v4_early_demux(struct sk_buff *skb);
int tcp_v4_rcv(struct sk_buff *skb);
int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);

2
include/net/udp.h
View File

@ -259,7 +259,7 @@ static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
}
void udp_v4_early_demux(struct sk_buff *skb);
int udp_v4_early_demux(struct sk_buff *skb);
bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
int udp_get_port(struct sock *sk, unsigned short snum,
int (*saddr_cmp)(const struct sock *,

25
net/ipv4/ip_input.c
View File

@ -311,9 +311,10 @@ drop:
static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
const struct iphdr *iph = ip_hdr(skb);
struct rtable *rt;
int (*edemux)(struct sk_buff *skb);
struct net_device *dev = skb->dev;
void (*edemux)(struct sk_buff *skb);
struct rtable *rt;
int err;
/* if ingress device is enslaved to an L3 master device pass the
* skb to its handler for processing
@ -331,7 +332,9 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
ipprot = rcu_dereference(inet_protos[protocol]);
if (ipprot && (edemux = READ_ONCE(ipprot->early_demux))) {
edemux(skb);
err = edemux(skb);
if (unlikely(err))
goto drop_error;
/* must reload iph, skb->head might have changed */
iph = ip_hdr(skb);
}
@ -342,13 +345,10 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
* how the packet travels inside Linux networking.
*/
if (!skb_valid_dst(skb)) {
int err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
iph->tos, dev);
if (unlikely(err)) {
if (err == -EXDEV)
__NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
goto drop;
}
err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
iph->tos, dev);
if (unlikely(err))
goto drop_error;
}
#ifdef CONFIG_IP_ROUTE_CLASSID
@ -399,6 +399,11 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
drop:
kfree_skb(skb);
return NET_RX_DROP;
drop_error:
if (err == -EXDEV)
__NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
goto drop;
}
/*

9
net/ipv4/tcp_ipv4.c
View File

@ -1503,23 +1503,23 @@ csum_err:
}
EXPORT_SYMBOL(tcp_v4_do_rcv);
void tcp_v4_early_demux(struct sk_buff *skb)
int tcp_v4_early_demux(struct sk_buff *skb)
{
const struct iphdr *iph;
const struct tcphdr *th;
struct sock *sk;
if (skb->pkt_type != PACKET_HOST)
return;
return 0;
if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
return;
return 0;
iph = ip_hdr(skb);
th = tcp_hdr(skb);
if (th->doff < sizeof(struct tcphdr) / 4)
return;
return 0;
sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
iph->saddr, th->source,
@ -1538,6 +1538,7 @@ void tcp_v4_early_demux(struct sk_buff *skb)
skb_dst_set_noref(skb, dst);
}
}
return 0;
}
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)

11
net/ipv4/udp.c
View File

@ -2221,7 +2221,7 @@ static struct sock *__udp4_lib_demux_lookup(struct net *net,
return NULL;
}
void udp_v4_early_demux(struct sk_buff *skb)
int udp_v4_early_demux(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
const struct iphdr *iph;
@ -2234,7 +2234,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
/* validate the packet */
if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
return;
return 0;
iph = ip_hdr(skb);
uh = udp_hdr(skb);
@ -2244,14 +2244,14 @@ void udp_v4_early_demux(struct sk_buff *skb)
struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
if (!in_dev)
return;
return 0;
/* we are supposed to accept bcast packets */
if (skb->pkt_type == PACKET_MULTICAST) {
ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
iph->protocol);
if (!ours)
return;
return 0;
}
sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
@ -2263,7 +2263,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
}
if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return;
return 0;
skb->sk = sk;
skb->destructor = sock_efree;
@ -2278,6 +2278,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
*/
skb_dst_set_noref(skb, dst);
}
return 0;
}
int udp_rcv(struct sk_buff *skb)