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5b1158e9 JK |
1 | /* (C) 1999-2001 Paul `Rusty' Russell |
2 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <linux/types.h> | |
bc3b2d7f | 10 | #include <linux/export.h> |
5b1158e9 | 11 | #include <linux/init.h> |
5b1158e9 JK |
12 | #include <linux/udp.h> |
13 | ||
14 | #include <linux/netfilter.h> | |
15 | #include <net/netfilter/nf_nat.h> | |
16 | #include <net/netfilter/nf_nat_core.h> | |
c7232c99 PM |
17 | #include <net/netfilter/nf_nat_l3proto.h> |
18 | #include <net/netfilter/nf_nat_l4proto.h> | |
5b1158e9 | 19 | |
c7232c99 | 20 | static u16 udp_port_rover; |
5b1158e9 | 21 | |
f43dc98b | 22 | static void |
c7232c99 PM |
23 | udp_unique_tuple(const struct nf_nat_l3proto *l3proto, |
24 | struct nf_conntrack_tuple *tuple, | |
25 | const struct nf_nat_range *range, | |
5b1158e9 JK |
26 | enum nf_nat_manip_type maniptype, |
27 | const struct nf_conn *ct) | |
28 | { | |
c7232c99 PM |
29 | nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct, |
30 | &udp_port_rover); | |
5b1158e9 JK |
31 | } |
32 | ||
f2ea825f | 33 | static bool |
3db05fea | 34 | udp_manip_pkt(struct sk_buff *skb, |
c7232c99 PM |
35 | const struct nf_nat_l3proto *l3proto, |
36 | unsigned int iphdroff, unsigned int hdroff, | |
5b1158e9 JK |
37 | const struct nf_conntrack_tuple *tuple, |
38 | enum nf_nat_manip_type maniptype) | |
39 | { | |
5b1158e9 | 40 | struct udphdr *hdr; |
5b1158e9 JK |
41 | __be16 *portptr, newport; |
42 | ||
3db05fea | 43 | if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) |
f2ea825f | 44 | return false; |
3db05fea | 45 | hdr = (struct udphdr *)(skb->data + hdroff); |
5b1158e9 | 46 | |
cbc9f2f4 | 47 | if (maniptype == NF_NAT_MANIP_SRC) { |
c7232c99 | 48 | /* Get rid of src port */ |
5b1158e9 JK |
49 | newport = tuple->src.u.udp.port; |
50 | portptr = &hdr->source; | |
51 | } else { | |
c7232c99 | 52 | /* Get rid of dst port */ |
5b1158e9 JK |
53 | newport = tuple->dst.u.udp.port; |
54 | portptr = &hdr->dest; | |
55 | } | |
3db05fea | 56 | if (hdr->check || skb->ip_summed == CHECKSUM_PARTIAL) { |
c7232c99 PM |
57 | l3proto->csum_update(skb, iphdroff, &hdr->check, |
58 | tuple, maniptype); | |
be0ea7d5 | 59 | inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, |
4b048d6d | 60 | false); |
5b1158e9 JK |
61 | if (!hdr->check) |
62 | hdr->check = CSUM_MANGLED_0; | |
63 | } | |
64 | *portptr = newport; | |
f2ea825f | 65 | return true; |
5b1158e9 JK |
66 | } |
67 | ||
c7232c99 PM |
68 | const struct nf_nat_l4proto nf_nat_l4proto_udp = { |
69 | .l4proto = IPPROTO_UDP, | |
5b1158e9 | 70 | .manip_pkt = udp_manip_pkt, |
c7232c99 | 71 | .in_range = nf_nat_l4proto_in_range, |
5b1158e9 | 72 | .unique_tuple = udp_unique_tuple, |
24de3d37 | 73 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
c7232c99 | 74 | .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, |
5b1158e9 JK |
75 | #endif |
76 | }; |