1 /* Shared library add-on to iptables to add masquerade support. */
8 #include <linux/netfilter_ipv4/ip_tables.h>
9 #include <linux/netfilter_ipv4/ip_nat_rule.h>
11 /* Function which prints out usage message. */
16 "MASQUERADE v%s options:\n"
17 " --to-ports <port>[-<port>]\n"
18 " Port (range) to map to.\n\n",
22 static struct option opts[] = {
23 { "to-ports", 1, 0, '1' },
27 /* Initialize the target. */
29 init(struct ipt_entry_target *t, unsigned int *nfcache)
31 struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data;
33 /* Actually, it's 0, but it's ignored at the moment. */
36 /* Can't cache this */
37 *nfcache |= NFC_UNKNOWN;
42 parse_ports(const char *arg, struct ip_nat_multi_range *mr)
47 mr->range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
50 if (port <= 0 || port > 65535)
51 exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);
53 dash = strchr(arg, '-');
55 mr->range[0].min.tcp.port
56 = mr->range[0].max.tcp.port
61 maxport = atoi(dash + 1);
62 if (maxport == 0 || maxport > 65535)
63 exit_error(PARAMETER_PROBLEM,
64 "Port `%s' not valid\n", dash+1);
66 /* People are stupid. Present reader excepted. */
67 exit_error(PARAMETER_PROBLEM,
68 "Port range `%s' funky\n", arg);
69 mr->range[0].min.tcp.port = htons(port);
70 mr->range[0].max.tcp.port = htons(maxport);
74 /* Function which parses command options; returns true if it
77 parse(int c, char **argv, int invert, unsigned int *flags,
78 const struct ipt_entry *entry,
79 struct ipt_entry_target **target)
82 struct ip_nat_multi_range *mr
83 = (struct ip_nat_multi_range *)(*target)->data;
85 if (entry->ip.proto == IPPROTO_TCP
86 || entry->ip.proto == IPPROTO_UDP)
94 exit_error(PARAMETER_PROBLEM,
95 "Need TCP or UDP with port specification");
97 if (check_inverse(optarg, &invert, NULL, 0))
98 exit_error(PARAMETER_PROBLEM,
99 "Unexpected `!' after --to-ports");
101 parse_ports(optarg, mr);
109 /* Final check; don't care. */
110 static void final_check(unsigned int flags)
114 /* Prints out the targinfo. */
116 print(const struct ipt_ip *ip,
117 const struct ipt_entry_target *target,
120 struct ip_nat_multi_range *mr
121 = (struct ip_nat_multi_range *)target->data;
122 struct ip_nat_range *r = &mr->range[0];
124 if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
125 printf("masq ports: ");
126 printf("%hu", ntohs(r->min.tcp.port));
127 if (r->max.tcp.port != r->min.tcp.port)
128 printf("-%hu", ntohs(r->max.tcp.port));
133 /* Saves the union ipt_targinfo in parsable form to stdout. */
135 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
137 struct ip_nat_multi_range *mr
138 = (struct ip_nat_multi_range *)target->data;
139 struct ip_nat_range *r = &mr->range[0];
141 if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
142 printf("--to-ports %hu", ntohs(r->min.tcp.port));
143 if (r->max.tcp.port != r->min.tcp.port)
144 printf("-%hu", ntohs(r->max.tcp.port));
150 struct iptables_target masq
154 IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
155 IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
167 register_target(&masq);