Re: [PATCH] net: fix the counter ICMP_MIB_INERRORS/ICMP6_MIB_INERRORS
From: Hannes Frederic Sowa <hidden>
Date: 2014-07-30 13:45:37
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...
quoted hunk ↗ jump to hunk
--- 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.
quoted hunk ↗ jump to hunk
} /*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