> On 2.4.21 all works fine
> In tcpdump on 2.4.21:
> 14:41:41.752557 somehost.auth > somehost1.32825: R 0:0(0) ack 217583467 win 0 (DF)
> In tcpdump on 2.4.22:
> nothing.......
Hi Diadon,
the problem seems to be that a dst for local input doesn't carry pmtu information, the pmtu
is set by rt_set_nexthop which is skipped for local input. The packet is dropped by send_reset
because of this check:
/* "Never happens" */
if (nskb->len > nskb->dst->pmtu)
goto free_nskb;;)
I've attached two possible fixes for this. The first one restores behaviour from before the
routing changes for LOCAL_OUT, the other one removes the check since obviously
"Never happens" is not true anymore (and it is not an error). Another possibility would
be something like "if (nskb->dst->pmtu && nskb->len > nskb->dst->pmtu) ..."
Someone from the coreteam should comment which solution is prefered.
Regards, Patrick
===== net/ipv4/netfilter/ipt_REJECT.c 1.13 vs edited =====
--- 1.13/net/ipv4/netfilter/ipt_REJECT.c Fri Jul 25 23:15:41 2003
+++ edited/net/ipv4/netfilter/ipt_REJECT.c Thu Sep 18 23:00:58 2003
@@ -34,16 +34,17 @@
attach(new_skb, nfct);
}
-static inline struct rtable *route_reverse(struct sk_buff *skb, int local)
+static inline struct rtable *route_reverse(struct sk_buff *skb, int hook)
{
struct iphdr *iph = skb->nh.iph;
struct dst_entry *odst;
struct rt_key key = {};
struct rtable *rt;
- if (local) {
+ if (hook != NF_IP_FORWARD) {
key.dst = iph->saddr;
- key.src = iph->daddr;
+ if (hook == NF_IP_LOCAL_IN)
+ key.src = iph->daddr;
key.tos = RT_TOS(iph->tos);
if (ip_route_output_key(&rt, &key) != 0)
@@ -75,7 +76,7 @@
}
/* Send RST reply */
-static void send_reset(struct sk_buff *oldskb, int local)
+static void send_reset(struct sk_buff *oldskb, int hook)
{
struct sk_buff *nskb;
struct tcphdr *otcph, *tcph;
@@ -104,7 +105,7 @@
csum_partial((char *)otcph, otcplen, 0)) != 0)
return;
- if ((rt = route_reverse(oldskb, local)) == NULL)
+ if ((rt = route_reverse(oldskb, hook)) == NULL)
return;
hh_len = (rt->u.dst.dev->hard_header_len + 15)&~15;
@@ -372,7 +373,7 @@
send_unreach(*pskb, ICMP_PKT_FILTERED);
break;
case IPT_TCP_RESET:
- send_reset(*pskb, hooknum == NF_IP_LOCAL_IN);
+ send_reset(*pskb, hooknum);
case IPT_ICMP_ECHOREPLY:
/* Doesn't happen. */
break;
===== net/ipv4/netfilter/ipt_REJECT.c 1.13 vs edited ===== --- 1.13/net/ipv4/netfilter/ipt_REJECT.c Fri Jul 25 23:15:41 2003 +++ edited/net/ipv4/netfilter/ipt_REJECT.c Thu Sep 18 23:28:49 2003 @@ -186,10 +186,6 @@ nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph, nskb->nh.iph->ihl); - /* "Never happens" */ - if (nskb->len > nskb->dst->pmtu) - goto free_nskb; - connection_attach(nskb, oldskb->nfct); NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
