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Date: Wed, 30 Jul 2014 15:45:30 +0200
From: Hannes Frederic Sowa <hannes@...essinduktion.org>
To: Duan Jiong <duanj.fnst@...fujitsu.com>
Cc: David Miller <davem@...emloft.net>, eric.dumazet@...il.com,
netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH] net: fix the counter
ICMP_MIB_INERRORS/ICMP6_MIB_INERRORS
On Di, 2014-07-29 at 16:19 +0800, Duan Jiong wrote:
> When dealing with ICMPv[46] Error Message, function icmp_socket_deliver()
> and icmpv6_notify() do some valid checks on packet's length, but then some
> protocols check packet's length redaudantly. So remove those duplicated
> statements, and increase counter ICMP_MIB_INERRORS/ICMP6_MIB_INERRORS in
> function icmp_socket_deliver() and icmpv6_notify() respectively.
>
> In addition, add missed counter in udp6/udplite6 when socket is NULL.
I am ok with adding the error counters, but...
> ---
> net/ipv4/icmp.c | 4 +++-
> net/ipv4/tcp_ipv4.c | 5 -----
> net/ipv6/icmp.c | 11 ++++++++---
> net/ipv6/udp.c | 8 ++++++--
> net/sctp/input.c | 5 -----
> 5 files changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
> index 42b7bcf..092400e 100644
> --- a/net/ipv4/icmp.c
> +++ b/net/ipv4/icmp.c
> @@ -663,8 +663,10 @@ static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
> /* Checkin full IP header plus 8 bytes of protocol to
> * avoid additional coding at protocol handlers.
> */
> - if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
> + if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
> + ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
> return;
> + }
>
> raw_icmp_error(skb, protocol, info);
>
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index 77cccda..715cf6b 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -342,11 +342,6 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
> int err;
> struct net *net = dev_net(icmp_skb->dev);
>
> - if (icmp_skb->len < (iph->ihl << 2) + 8) {
> - ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
> - return;
> - }
> -
> sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
> iph->saddr, th->source, inet_iif(icmp_skb));
> if (!sk) {
> diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
> index f6c84a6..8ca3cc0 100644
> --- a/net/ipv6/icmp.c
> +++ b/net/ipv6/icmp.c
> @@ -626,9 +626,10 @@ void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
> int inner_offset;
> __be16 frag_off;
> u8 nexthdr;
> + struct net *net = dev_net(skb->dev);
>
> if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
> - return;
> + goto out;
>
> nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
> if (ipv6_ext_hdr(nexthdr)) {
> @@ -636,14 +637,14 @@ void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
> inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
> &nexthdr, &frag_off);
> if (inner_offset<0)
> - return;
> + goto out;
> } else {
> inner_offset = sizeof(struct ipv6hdr);
> }
>
> /* Checkin header including 8 bytes of inner protocol header. */
> if (!pskb_may_pull(skb, inner_offset+8))
> - return;
> + goto out;
>
> /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
> Without this we will not able f.e. to make source routed
> @@ -659,6 +660,10 @@ void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
> rcu_read_unlock();
>
> raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
> + return;
> +
> +out:
> + ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
... please don't use __in6_dev_get in BH without rcu, but inet6_iif. You
risk a lockdep error otherwise. You don't have rtnl locked and no RCU
read lock.
> }
>
> /*
> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
> index 7092ff7..f13d297 100644
> --- a/net/ipv6/udp.c
> +++ b/net/ipv6/udp.c
> @@ -534,11 +534,15 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
> struct udphdr *uh = (struct udphdr*)(skb->data+offset);
> struct sock *sk;
> int err;
> + struct net *net = dev_net(skb->dev);
>
> - sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
> + sk = __udp6_lib_lookup(net, daddr, uh->dest,
> saddr, uh->source, inet6_iif(skb), udptable);
> - if (sk == NULL)
> + if (sk == NULL) {
> + ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
> + ICMP6_MIB_INERRORS);
It is not really necessary here, as you like.
Bye,
Hannes
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