static inline int
set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo, int inward)
{
- struct tcphdr _tcph, *th;
+ struct tcphdr _tcph, *tcph;
u_int16_t diffs[2];
/* Not enought header? */
- th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4,
- sizeof(_tcph), &_tcph);
- if (th == NULL)
+ tcph = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4,
+ sizeof(_tcph), &_tcph);
+ if (!tcph)
return 0;
- diffs[0] = ((u_int16_t *)th)[6];
- if (einfo->operation & IPT_ECN_OP_SET_ECE)
- th->ece = einfo->proto.tcp.ece;
+ if (!(einfo->operation & IPT_ECN_OP_SET_ECE
+ || tcph->ece == einfo->proto.tcp.ece)
+ && (!(einfo->operation & IPT_ECN_OP_SET_CWR
+ || tcph->cwr == einfo->proto.tcp.cwr)))
+ return 1;
+
+ if (!skb_ip_make_writable(pskb, (*pskb)->nh.iph->ihl*4+sizeof(*tcph)))
+ return 0;
+ tcph = (void *)(*pskb)->nh.iph + (*pskb)->nh.iph->ihl*4;
+ diffs[0] = ((u_int16_t *)tcph)[6];
+ if (einfo->operation & IPT_ECN_OP_SET_ECE)
+ tcph->ece = einfo->proto.tcp.ece;
if (einfo->operation & IPT_ECN_OP_SET_CWR)
- th->cwr = einfo->proto.tcp.cwr;
- diffs[1] = ((u_int16_t *)&th)[6];
-
- /* Only mangle if it's changed. */
- if (diffs[0] != diffs[1]) {
- diffs[0] = diffs[0] ^ 0xFFFF;
- if (!skb_ip_make_writable(pskb,
- (*pskb)->nh.iph->ihl*4+sizeof(_tcph)))
+ tcph->cwr = einfo->proto.tcp.cwr;
+ diffs[1] = ((u_int16_t *)tcph)[6];
+ diffs[0] = diffs[0] ^ 0xFFFF;
+
+ if ((*pskb)->ip_summed != CHECKSUM_HW)
+ tcph->check = csum_fold(csum_partial((char *)diffs,
+ sizeof(diffs),
+ tcph->check^0xFFFF));
+ else
+ if (skb_checksum_help(*pskb, inward))
return 0;
-
- if (th != &_tcph)
- memcpy(&_tcph, th, sizeof(_tcph));
-
- if ((*pskb)->ip_summed != CHECKSUM_HW)
- _tcph.check = csum_fold(csum_partial((char *)diffs,
- sizeof(diffs),
- _tcph.check^0xFFFF));
- memcpy((*pskb)->data + (*pskb)->nh.iph->ihl*4,
- &_tcph, sizeof(_tcph));
- if ((*pskb)->ip_summed == CHECKSUM_HW)
- if (skb_checksum_help(pskb, inward))
- return 0;
- (*pskb)->nfcache |= NFC_ALTERED;
- }
+ (*pskb)->nfcache |= NFC_ALTERED;
return 1;
}
}
if ((einfo->operation & (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR))
- && e->ip.proto != IPPROTO_TCP) {
+ && (e->ip.proto != IPPROTO_TCP || (e->ip.invflags & IPT_INV_PROTO))) {
printk(KERN_WARNING "ECN: cannot use TCP operations on a "
"non-tcp rule\n");
return 0;