IPv4: early demux can return an error code

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>

diff --git a/include/net/protocol.h b/include/net/protocol.h
index 65ba335b0e7e66bb7f1b4bd279d31e616e0dd31e..4fc75f7ae23beb47674b04df27ac6ef4594679fe 100644 (file)
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -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,

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3bc910a9bfc6f39ed0c8a4b451cf80e579de66ad..89974c5286d8ae4db63def6822ae5b0dc93cddf9 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -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);

diff --git a/include/net/udp.h b/include/net/udp.h
index 12dfbfe2e2d7853427e244f9d6e2e39ca19bd41e..6c759c8594e25c7f9f79dc6bf76325c39e705f94 100644 (file)
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -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 *,

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index fa2dc8f692c631f1ff7fe814c3ee27f0de2a41d8..57fc13c6ab2b7843a4fdb11680c82fc342f465c7 100644 (file)
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -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;
 }
 
 /*

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d9416b5162bc1bdd1acd34fcb4da21cb6b62d0ae..85164d4d3e537537c87d74c00172592c860d4dfb 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ef29df8648e4d388547269fe6f972e8ab473419e..9b30f821fe96bc77640aff97717231e416fb4dc6 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -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)