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net: ipv6: remove redundant statistics in ipv6_hop_jumbo() 

There are two call chains for ipv6_hop_jumbo(). The first one is:

ipv6_destopt_rcv() -> ip6_parse_tlv() -> ipv6_hop_jumbo()

On this call chain, the drop statistics will be done in
ipv6_destopt_rcv() with 'IPSTATS_MIB_INHDRERRORS' if ipv6_hop_jumbo()
returns false.

The second call chain is:

ip6_rcv_core() -> ipv6_parse_hopopts() -> ip6_parse_tlv()

And the drop statistics will also be done in ip6_rcv_core() with
'IPSTATS_MIB_INHDRERRORS' if ipv6_hop_jumbo() returns false.

Therefore, the statistics in ipv6_hop_jumbo() is redundant, which
means the drop is counted twice. The statistics in ipv6_hop_jumbo()
is almost the same as the outside, except the
'IPSTATS_MIB_INTRUNCATEDPKTS', which seems that we have to ignore it.

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>
This commit is contained in:
Menglong Dong 2022-04-13 16:15:57 +08:00 committed by David S. Miller
parent 1ad6d548e2
commit bba9808349
1 changed files with 1 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
net/ipv6/exthdrs.c
View File

@ -994,33 +994,26 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
{
const unsigned char *nh = skb_network_header(skb);
struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
struct net *net = ipv6_skb_net(skb);
u32 pkt_len;
if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
nh[optoff+1]);
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
goto drop;
}
pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
if (pkt_len <= IPV6_MAXPLEN) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
return false;
}
if (ipv6_hdr(skb)->payload_len) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
return false;
}
if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
if (pkt_len > skb->len - sizeof(struct ipv6hdr))
goto drop;
}
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
goto drop;