Messages in this thread | | | Date | Wed, 13 Apr 2022 13:40:59 -0700 | Subject | Re: [PATCH net-next 8/9] net: ipv6: add skb drop reasons to ip6_rcv_core() | From | Eric Dumazet <> |
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On 4/13/22 01:15, menglong8.dong@gmail.com wrote: > From: Menglong Dong <imagedong@tencent.com> > > 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> > --- > net/ipv6/ip6_input.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c > index b4880c7c84eb..1b925ecb26e9 100644 > --- 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))
idev can be NULL here (according to surrounding code), and we crash :/
> + 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; > } >
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