1 /* Shared library add-on to iptables to add redirect 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 "REDIRECT 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. */
40 parse_ports(const char *arg, struct ip_nat_multi_range *mr)
45 mr->range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
48 if (port == 0 || port > 65535)
49 exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);
51 dash = strchr(arg, '-');
53 mr->range[0].min.tcp.port
54 = mr->range[0].max.tcp.port
59 maxport = atoi(dash + 1);
60 if (maxport == 0 || maxport > 65535)
61 exit_error(PARAMETER_PROBLEM,
62 "Port `%s' not valid\n", dash+1);
64 /* People are stupid. */
65 exit_error(PARAMETER_PROBLEM,
66 "Port range `%s' funky\n", arg);
67 mr->range[0].min.tcp.port = htons(port);
68 mr->range[0].max.tcp.port = htons(maxport);
72 /* Function which parses command options; returns true if it
75 parse(int c, char **argv, int invert, unsigned int *flags,
76 const struct ipt_entry *entry,
77 struct ipt_entry_target **target)
79 struct ip_nat_multi_range *mr
80 = (struct ip_nat_multi_range *)(*target)->data;
83 if (entry->ip.proto == IPPROTO_TCP
84 || entry->ip.proto == IPPROTO_UDP)
92 exit_error(PARAMETER_PROBLEM,
93 "Need TCP or UDP with port specification");
95 if (check_inverse(optarg, &invert, NULL, 0))
96 exit_error(PARAMETER_PROBLEM,
97 "Unexpected `!' after --to-ports");
99 parse_ports(optarg, mr);
107 /* Final check; don't care. */
108 static void final_check(unsigned int flags)
112 /* Prints out the targinfo. */
114 print(const struct ipt_ip *ip,
115 const struct ipt_entry_target *target,
118 struct ip_nat_multi_range *mr
119 = (struct ip_nat_multi_range *)target->data;
120 struct ip_nat_range *r = &mr->range[0];
122 if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
123 printf("redir ports ");
124 printf("%hu", ntohs(r->min.tcp.port));
125 if (r->max.tcp.port != r->min.tcp.port)
126 printf("-%hu", ntohs(r->max.tcp.port));
131 /* Saves the union ipt_targinfo in parsable form to stdout. */
133 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
135 struct ip_nat_multi_range *mr
136 = (struct ip_nat_multi_range *)target->data;
137 struct ip_nat_range *r = &mr->range[0];
139 if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
140 printf("--to-ports ");
141 printf("%hu", ntohs(r->min.tcp.port));
142 if (r->max.tcp.port != r->min.tcp.port)
143 printf("-%hu", ntohs(r->max.tcp.port));
148 static struct iptables_target redir = {
151 .version = IPTABLES_VERSION,
152 .size = IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
153 .userspacesize = IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
157 .final_check = &final_check,
165 register_target(&redir);