net: ipv6: add skb drop reasons to ip6_rcv_core()

Replace kfree_skb() used in ip6_rcv_core() with kfree_skb_reason().
No new drop reasons are added.

Seems now we use 'SKB_DROP_REASON_IP_INHDR' for too many case during
ipv6 header parse or check, just like what 'IPSTATS_MIB_INHDRERRORS'
do. Will it be too general and hard to know what happened?

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index b4880c7c84eb4b6291cf98a9b24330dac9a6ac7d..1b925ecb26e95f8ca08142f55375a02004addf75 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -145,13 +145,14 @@ static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
 static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
                                    struct net *net)
 {
+       enum skb_drop_reason reason;
        const struct ipv6hdr *hdr;
        u32 pkt_len;
        struct inet6_dev *idev;
 
        if (skb->pkt_type == PACKET_OTHERHOST) {
                dev_core_stats_rx_otherhost_dropped_inc(skb->dev);
-               kfree_skb(skb);
+               kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST);
                return NULL;
        }
 
@@ -161,9 +162,12 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
 
        __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
 
+       SKB_DR_SET(reason, NOT_SPECIFIED);
        if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
            !idev || unlikely(idev->cnf.disable_ipv6)) {
                __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
+               if (unlikely(idev->cnf.disable_ipv6))
+                       SKB_DR_SET(reason, IPV6DISABLED);
                goto drop;
        }
 
@@ -187,8 +191,10 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
 
        hdr = ipv6_hdr(skb);
 
-       if (hdr->version != 6)
+       if (hdr->version != 6) {
+               SKB_DR_SET(reason, UNHANDLED_PROTO);
                goto err;
+       }
 
        __IP6_ADD_STATS(net, idev,
                        IPSTATS_MIB_NOECTPKTS +
@@ -226,8 +232,10 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
        if (!ipv6_addr_is_multicast(&hdr->daddr) &&
            (skb->pkt_type == PACKET_BROADCAST ||
             skb->pkt_type == PACKET_MULTICAST) &&
-           idev->cnf.drop_unicast_in_l2_multicast)
+           idev->cnf.drop_unicast_in_l2_multicast) {
+               SKB_DR_SET(reason, UNICAST_IN_L2_MULTICAST);
                goto err;
+       }
 
        /* RFC4291 2.7
         * Nodes must not originate a packet to a multicast address whose scope
@@ -256,12 +264,11 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
                if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
                        __IP6_INC_STATS(net,
                                        idev, IPSTATS_MIB_INTRUNCATEDPKTS);
+                       SKB_DR_SET(reason, PKT_TOO_SMALL);
                        goto drop;
                }
-               if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
-                       __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
-                       goto drop;
-               }
+               if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
+                       goto err;
                hdr = ipv6_hdr(skb);
        }
 
@@ -282,9 +289,10 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
        return skb;
 err:
        __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+       SKB_DR_OR(reason, IP_INHDR);
 drop:
        rcu_read_unlock();
-       kfree_skb(skb);
+       kfree_skb_reason(skb, reason);
        return NULL;
 }