/net/ipv4/netfilter/nf_nat_proto_icmp.c
https://bitbucket.org/abioy/linux · C · 84 lines · 66 code · 10 blank · 8 comment · 5 complexity · b083f61129443b70539f85b2c7a5091e MD5 · raw file
- /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #include <linux/types.h>
- #include <linux/init.h>
- #include <linux/ip.h>
- #include <linux/icmp.h>
- #include <linux/netfilter.h>
- #include <net/netfilter/nf_nat.h>
- #include <net/netfilter/nf_nat_core.h>
- #include <net/netfilter/nf_nat_rule.h>
- #include <net/netfilter/nf_nat_protocol.h>
- static bool
- icmp_in_range(const struct nf_conntrack_tuple *tuple,
- enum nf_nat_manip_type maniptype,
- const union nf_conntrack_man_proto *min,
- const union nf_conntrack_man_proto *max)
- {
- return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
- ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
- }
- static bool
- icmp_unique_tuple(struct nf_conntrack_tuple *tuple,
- const struct nf_nat_range *range,
- enum nf_nat_manip_type maniptype,
- const struct nf_conn *ct)
- {
- static u_int16_t id;
- unsigned int range_size;
- unsigned int i;
- range_size = ntohs(range->max.icmp.id) - ntohs(range->min.icmp.id) + 1;
- /* If no range specified... */
- if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED))
- range_size = 0xFFFF;
- for (i = 0; i < range_size; i++, id++) {
- tuple->src.u.icmp.id = htons(ntohs(range->min.icmp.id) +
- (id % range_size));
- if (!nf_nat_used_tuple(tuple, ct))
- return true;
- }
- return false;
- }
- static bool
- icmp_manip_pkt(struct sk_buff *skb,
- unsigned int iphdroff,
- const struct nf_conntrack_tuple *tuple,
- enum nf_nat_manip_type maniptype)
- {
- const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
- struct icmphdr *hdr;
- unsigned int hdroff = iphdroff + iph->ihl*4;
- if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
- return false;
- hdr = (struct icmphdr *)(skb->data + hdroff);
- inet_proto_csum_replace2(&hdr->checksum, skb,
- hdr->un.echo.id, tuple->src.u.icmp.id, 0);
- hdr->un.echo.id = tuple->src.u.icmp.id;
- return true;
- }
- const struct nf_nat_protocol nf_nat_protocol_icmp = {
- .protonum = IPPROTO_ICMP,
- .me = THIS_MODULE,
- .manip_pkt = icmp_manip_pkt,
- .in_range = icmp_in_range,
- .unique_tuple = icmp_unique_tuple,
- #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
- .range_to_nlattr = nf_nat_proto_range_to_nlattr,
- .nlattr_to_range = nf_nat_proto_nlattr_to_range,
- #endif
- };