IPv4: early demux can return an error code
authorPaolo Abeni <pabeni@redhat.com>
Thu, 28 Sep 2017 13:51:36 +0000 (15:51 +0200)
committerDavid S. Miller <davem@davemloft.net>
Sun, 1 Oct 2017 02:55:47 +0000 (03:55 +0100)
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>
include/net/protocol.h
include/net/tcp.h
include/net/udp.h
net/ipv4/ip_input.c
net/ipv4/tcp_ipv4.c
net/ipv4/udp.c

index 65ba335b0e7e66bb7f1b4bd279d31e616e0dd31e..4fc75f7ae23beb47674b04df27ac6ef4594679fe 100644 (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,
index 3bc910a9bfc6f39ed0c8a4b451cf80e579de66ad..89974c5286d8ae4db63def6822ae5b0dc93cddf9 100644 (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);
index 12dfbfe2e2d7853427e244f9d6e2e39ca19bd41e..6c759c8594e25c7f9f79dc6bf76325c39e705f94 100644 (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 *,
index fa2dc8f692c631f1ff7fe814c3ee27f0de2a41d8..57fc13c6ab2b7843a4fdb11680c82fc342f465c7 100644 (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;
 }
 
 /*
index d9416b5162bc1bdd1acd34fcb4da21cb6b62d0ae..85164d4d3e537537c87d74c00172592c860d4dfb 100644 (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)
index ef29df8648e4d388547269fe6f972e8ab473419e..9b30f821fe96bc77640aff97717231e416fb4dc6 100644 (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)