1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
9 #include <linux/types.h>
10 #include <linux/init.h>
11 #include <linux/netfilter.h>
13 #include <linux/udp.h>
16 #include <linux/netfilter_ipv4/ip_nat.h>
17 #include <linux/netfilter_ipv4/ip_nat_core.h>
18 #include <linux/netfilter_ipv4/ip_nat_rule.h>
19 #include <linux/netfilter_ipv4/ip_nat_protocol.h>
22 udp_in_range(const struct ip_conntrack_tuple *tuple,
23 enum ip_nat_manip_type maniptype,
24 const union ip_conntrack_manip_proto *min,
25 const union ip_conntrack_manip_proto *max)
29 if (maniptype == IP_NAT_MANIP_SRC)
30 port = tuple->src.u.udp.port;
32 port = tuple->dst.u.udp.port;
34 return ntohs(port) >= ntohs(min->udp.port)
35 && ntohs(port) <= ntohs(max->udp.port);
39 udp_unique_tuple(struct ip_conntrack_tuple *tuple,
40 const struct ip_nat_range *range,
41 enum ip_nat_manip_type maniptype,
42 const struct ip_conntrack *conntrack)
44 static u_int16_t port;
46 unsigned int range_size, min, i;
48 if (maniptype == IP_NAT_MANIP_SRC)
49 portptr = &tuple->src.u.udp.port;
51 portptr = &tuple->dst.u.udp.port;
53 /* If no range specified... */
54 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) {
55 /* If it's dst rewrite, can't change port */
56 if (maniptype == IP_NAT_MANIP_DST)
59 if (ntohs(*portptr) < 1024) {
60 /* Loose convention: >> 512 is credential passing */
61 if (ntohs(*portptr)<512) {
63 range_size = 511 - min + 1;
66 range_size = 1023 - min + 1;
70 range_size = 65535 - 1024 + 1;
73 min = ntohs(range->min.udp.port);
74 range_size = ntohs(range->max.udp.port) - min + 1;
77 for (i = 0; i < range_size; i++, port++) {
78 *portptr = htons(min + port % range_size);
79 if (!ip_nat_used_tuple(tuple, conntrack))
86 udp_manip_pkt(struct sk_buff **pskb,
87 unsigned int iphdroff,
88 const struct ip_conntrack_tuple *tuple,
89 enum ip_nat_manip_type maniptype)
91 struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff);
93 unsigned int hdroff = iphdroff + iph->ihl*4;
95 u16 *portptr, newport;
97 if (!skb_make_writable(pskb, hdroff + sizeof(*hdr)))
100 iph = (struct iphdr *)((*pskb)->data + iphdroff);
101 hdr = (struct udphdr *)((*pskb)->data + hdroff);
103 if (maniptype == IP_NAT_MANIP_SRC) {
104 /* Get rid of src ip and src pt */
106 newip = tuple->src.ip;
107 newport = tuple->src.u.udp.port;
108 portptr = &hdr->source;
110 /* Get rid of dst ip and dst pt */
112 newip = tuple->dst.ip;
113 newport = tuple->dst.u.udp.port;
114 portptr = &hdr->dest;
116 if (hdr->check) /* 0 is a special case meaning no checksum */
117 hdr->check = ip_nat_cheat_check(~oldip, newip,
118 ip_nat_cheat_check(*portptr ^ 0xFFFF,
126 udp_print(char *buffer,
127 const struct ip_conntrack_tuple *match,
128 const struct ip_conntrack_tuple *mask)
130 unsigned int len = 0;
132 if (mask->src.u.udp.port)
133 len += sprintf(buffer + len, "srcpt=%u ",
134 ntohs(match->src.u.udp.port));
137 if (mask->dst.u.udp.port)
138 len += sprintf(buffer + len, "dstpt=%u ",
139 ntohs(match->dst.u.udp.port));
145 udp_print_range(char *buffer, const struct ip_nat_range *range)
147 if (range->min.udp.port != 0 || range->max.udp.port != 0xFFFF) {
148 if (range->min.udp.port == range->max.udp.port)
149 return sprintf(buffer, "port %u ",
150 ntohs(range->min.udp.port));
152 return sprintf(buffer, "ports %u-%u ",
153 ntohs(range->min.udp.port),
154 ntohs(range->max.udp.port));
159 struct ip_nat_protocol ip_nat_protocol_udp = {
161 .protonum = IPPROTO_UDP,
163 .manip_pkt = udp_manip_pkt,
164 .in_range = udp_in_range,
165 .unique_tuple = udp_unique_tuple,
167 .print_range = udp_print_range,
168 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
169 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
170 .range_to_nfattr = ip_nat_port_range_to_nfattr,
171 .nfattr_to_range = ip_nat_port_nfattr_to_range,