/* Small and modified version of icmp_rcv */
static int
icmp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
unsigned int hooknum)
{
struct icmphdr _ih, *icmph;
/* Not enough header? */
icmph = skb_header_pointer(skb, skb->nh.iph->ihl*4, sizeof(_ih), &_ih);
if (icmph == NULL) {
if (LOG_INVALID(IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"ip_ct_icmp: short packet ");
return -NF_ACCEPT;
}
/* See ip_conntrack_proto_tcp.c */
if (hooknum != NF_IP_PRE_ROUTING)
goto checksum_skipped;
switch (skb->ip_summed) {
case CHECKSUM_HW:
if (!(u16)csum_fold(skb->csum))
break;
/* fall through */
case CHECKSUM_NONE:
skb->csum = 0;
if (__skb_checksum_complete(skb)) {
if (LOG_INVALID(IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"ip_ct_icmp: bad ICMP checksum ");
return -NF_ACCEPT;
}
}
checksum_skipped:
/*
* 18 is the highest 'known' ICMP type. Anything else is a mystery
*
* RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
* discarded.
*/
if (icmph->type > NR_ICMP_TYPES) {
if (LOG_INVALID(IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"ip_ct_icmp: invalid ICMP type ");
return -NF_ACCEPT;
}
/* Need to track icmp error message? */
if (icmph->type != ICMP_DEST_UNREACH
&& icmph->type != ICMP_SOURCE_QUENCH
&& icmph->type != ICMP_TIME_EXCEEDED
&& icmph->type != ICMP_PARAMETERPROB
&& icmph->type != ICMP_REDIRECT)
return NF_ACCEPT;
return icmp_error_message(skb, ctinfo, hooknum);
}
/* Small and modified version of icmp_rcv */
static int
icmp_error(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb, unsigned int dataoff,
enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
{
const struct icmphdr *icmph;
struct icmphdr _ih;
/* Not enough header? */
icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih);
if (icmph == NULL) {
if (LOG_INVALID(net, IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"nf_ct_icmp: short packet ");
return -NF_ACCEPT;
}
/* See ip_conntrack_proto_tcp.c */
if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
nf_ip_checksum(skb, hooknum, dataoff, 0)) {
if (LOG_INVALID(net, IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"nf_ct_icmp: bad HW ICMP checksum ");
return -NF_ACCEPT;
}
/*
* 18 is the highest 'known' ICMP type. Anything else is a mystery
*
* RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
* discarded.
*/
if (icmph->type > NR_ICMP_TYPES) {
if (LOG_INVALID(net, IPPROTO_ICMP))
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
"nf_ct_icmp: invalid ICMP type ");
return -NF_ACCEPT;
}
/* Need to track icmp error message? */
if (icmph->type != ICMP_DEST_UNREACH &&
icmph->type != ICMP_SOURCE_QUENCH &&
icmph->type != ICMP_TIME_EXCEEDED &&
icmph->type != ICMP_PARAMETERPROB &&
icmph->type != ICMP_REDIRECT)
return NF_ACCEPT;
return icmp_error_message(net, tmpl, skb, ctinfo, hooknum);
}