diff options
Diffstat (limited to 'kernel/net/ipv4/netfilter/nf_nat_proto_icmp.c')
-rw-r--r-- | kernel/net/ipv4/netfilter/nf_nat_proto_icmp.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/kernel/net/ipv4/netfilter/nf_nat_proto_icmp.c b/kernel/net/ipv4/netfilter/nf_nat_proto_icmp.c new file mode 100644 index 000000000..4557b4ab8 --- /dev/null +++ b/kernel/net/ipv4/netfilter/nf_nat_proto_icmp.c @@ -0,0 +1,83 @@ +/* (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/export.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_l4proto.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 void +icmp_unique_tuple(const struct nf_nat_l3proto *l3proto, + 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_proto.icmp.id) - + ntohs(range->min_proto.icmp.id) + 1; + /* If no range specified... */ + if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) + range_size = 0xFFFF; + + for (i = 0; ; ++id) { + tuple->src.u.icmp.id = htons(ntohs(range->min_proto.icmp.id) + + (id % range_size)); + if (++i == range_size || !nf_nat_used_tuple(tuple, ct)) + return; + } + return; +} + +static bool +icmp_manip_pkt(struct sk_buff *skb, + const struct nf_nat_l3proto *l3proto, + unsigned int iphdroff, unsigned int hdroff, + const struct nf_conntrack_tuple *tuple, + enum nf_nat_manip_type maniptype) +{ + struct icmphdr *hdr; + + 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_l4proto nf_nat_l4proto_icmp = { + .l4proto = IPPROTO_ICMP, + .manip_pkt = icmp_manip_pkt, + .in_range = icmp_in_range, + .unique_tuple = icmp_unique_tuple, +#if IS_ENABLED(CONFIG_NF_CT_NETLINK) + .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, +#endif +}; |