macvlan: handle fragmented multicast frames

Fragmented multicast frames are delivered to a single macvlan port,
because ip defrag logic considers other samples are redundant.

Implement a defrag step before trying to send the multicast frame.

Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 49 insertions, 38 deletions

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 24cf942e131..a3ce3d4561e 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -169,6 +169,9 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 
         port = macvlan_port_get_rcu(skb->dev);
         if (is_multicast_ether_addr(eth->h_dest)) {
+                skb = ip_check_defrag(skb, IP_DEFRAG_MACVLAN);
+                if (!skb)
+                        return RX_HANDLER_CONSUMED;
                 src = macvlan_hash_lookup(port, eth->h_source);
                 if (!src)
                         /* frame comes from an external address */
diff --git a/include/net/ip.h b/include/net/ip.h
index aa76c7a4d9c..c7e066a1c61 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -406,9 +406,18 @@ enum ip_defrag_users {
         IP_DEFRAG_VS_OUT,
         IP_DEFRAG_VS_FWD,
         IP_DEFRAG_AF_PACKET,
+        IP_DEFRAG_MACVLAN,
 };
 
 int ip_defrag(struct sk_buff *skb, u32 user);
+#ifdef CONFIG_INET
+struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
+#else
+static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
+{
+        return skb;
+}
+#endif
 int ip_frag_mem(struct net *net);
 int ip_frag_nqueues(struct net *net);
 
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 0e0ab98abc6..763589ad673 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -682,6 +682,42 @@ int ip_defrag(struct sk_buff *skb, u32 user)
 }
 EXPORT_SYMBOL(ip_defrag);
 
+struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
+{
+        const struct iphdr *iph;
+        u32 len;
+
+        if (skb->protocol != htons(ETH_P_IP))
+                return skb;
+
+        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+                return skb;
+
+        iph = ip_hdr(skb);
+        if (iph->ihl < 5 || iph->version != 4)
+                return skb;
+        if (!pskb_may_pull(skb, iph->ihl*4))
+                return skb;
+        iph = ip_hdr(skb);
+        len = ntohs(iph->tot_len);
+        if (skb->len < len || len < (iph->ihl * 4))
+                return skb;
+
+        if (ip_is_fragment(ip_hdr(skb))) {
+                skb = skb_share_check(skb, GFP_ATOMIC);
+                if (skb) {
+                        if (pskb_trim_rcsum(skb, len))
+                                return skb;
+                        memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+                        if (ip_defrag(skb, user))
+                                return NULL;
+                        skb->rxhash = 0;
+                }
+        }
+        return skb;
+}
+EXPORT_SYMBOL(ip_check_defrag);
+
 #ifdef CONFIG_SYSCTL
 static int zero;
 
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 7b5f0325301..03bb45adf2f 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1213,43 +1213,6 @@ static struct sock *fanout_demux_cpu(struct packet_fanout *f, struct sk_buff *sk
         return f->arr[cpu % num];
 }
 
-static struct sk_buff *fanout_check_defrag(struct sk_buff *skb)
-{
-#ifdef CONFIG_INET
-        const struct iphdr *iph;
-        u32 len;
-
-        if (skb->protocol != htons(ETH_P_IP))
-                return skb;
-
-        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
-                return skb;
-
-        iph = ip_hdr(skb);
-        if (iph->ihl < 5 || iph->version != 4)
-                return skb;
-        if (!pskb_may_pull(skb, iph->ihl*4))
-                return skb;
-        iph = ip_hdr(skb);
-        len = ntohs(iph->tot_len);
-        if (skb->len < len || len < (iph->ihl * 4))
-                return skb;
-
-        if (ip_is_fragment(ip_hdr(skb))) {
-                skb = skb_share_check(skb, GFP_ATOMIC);
-                if (skb) {
-                        if (pskb_trim_rcsum(skb, len))
-                                return skb;
-                        memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
-                        if (ip_defrag(skb, IP_DEFRAG_AF_PACKET))
-                                return NULL;
-                        skb->rxhash = 0;
-                }
-        }
-#endif
-        return skb;
-}
-
 static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
                              struct packet_type *pt, struct net_device *orig_dev)
 {
@@ -1268,7 +1231,7 @@ static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
         case PACKET_FANOUT_HASH:
         default:
                 if (f->defrag) {
-                        skb = fanout_check_defrag(skb);
+                        skb = ip_check_defrag(skb, IP_DEFRAG_AF_PACKET);
                         if (!skb)
                                 return 0;
                 }