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, *portptr;
45 unsigned int range_size, min, i;
47 if (maniptype == IP_NAT_MANIP_SRC)
48 portptr = &tuple->src.u.udp.port;
50 portptr = &tuple->dst.u.udp.port;
52 /* If no range specified... */
53 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) {
54 /* If it's dst rewrite, can't change port */
55 if (maniptype == IP_NAT_MANIP_DST)
58 if (ntohs(*portptr) < 1024) {
59 /* Loose convention: >> 512 is credential passing */
60 if (ntohs(*portptr)<512) {
62 range_size = 511 - min + 1;
65 range_size = 1023 - min + 1;
69 range_size = 65535 - 1024 + 1;
72 min = ntohs(range->min.udp.port);
73 range_size = ntohs(range->max.udp.port) - min + 1;
76 for (i = 0; i < range_size; i++, port++) {
77 *portptr = htons(min + port % range_size);
78 if (!ip_nat_used_tuple(tuple, conntrack))
85 udp_manip_pkt(struct sk_buff **pskb,
87 const struct ip_conntrack_manip *manip,
88 enum ip_nat_manip_type maniptype)
94 if (!skb_ip_make_writable(pskb, hdroff + sizeof(hdr)))
97 hdr = (void *)(*pskb)->data + hdroff;
98 if (maniptype == IP_NAT_MANIP_SRC) {
99 /* Get rid of src ip and src pt */
100 oldip = (*pskb)->nh.iph->saddr;
101 portptr = &hdr->source;
103 /* Get rid of dst ip and dst pt */
104 oldip = (*pskb)->nh.iph->daddr;
105 portptr = &hdr->dest;
107 if (hdr->check) /* 0 is a special case meaning no checksum */
108 hdr->check = ip_nat_cheat_check(~oldip, manip->ip,
109 ip_nat_cheat_check(*portptr ^ 0xFFFF,
112 *portptr = manip->u.udp.port;
117 udp_print(char *buffer,
118 const struct ip_conntrack_tuple *match,
119 const struct ip_conntrack_tuple *mask)
121 unsigned int len = 0;
123 if (mask->src.u.udp.port)
124 len += sprintf(buffer + len, "srcpt=%u ",
125 ntohs(match->src.u.udp.port));
128 if (mask->dst.u.udp.port)
129 len += sprintf(buffer + len, "dstpt=%u ",
130 ntohs(match->dst.u.udp.port));
136 udp_print_range(char *buffer, const struct ip_nat_range *range)
138 if (range->min.udp.port != 0 || range->max.udp.port != 0xFFFF) {
139 if (range->min.udp.port == range->max.udp.port)
140 return sprintf(buffer, "port %u ",
141 ntohs(range->min.udp.port));
143 return sprintf(buffer, "ports %u-%u ",
144 ntohs(range->min.udp.port),
145 ntohs(range->max.udp.port));
150 struct ip_nat_protocol ip_nat_protocol_udp
151 = { "UDP", IPPROTO_UDP,