Merge commit 'origin/trunk@12184' into fedora

[iptables.git] / trunk / extensions / libipt_MASQUERADE.c

diff --git a/trunk/extensions/libipt_MASQUERADE.c b/trunk/extensions/libipt_MASQUERADE.c
new file mode 100644 (file)
index 0000000..ea4f5cd
--- /dev/null
+++ b/trunk/extensions/libipt_MASQUERADE.c
@@ -0,0 +1,168 @@
+/* Shared library add-on to iptables to add masquerade support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter/nf_nat.h>
+
+/* Function which prints out usage message. */
+static void MASQUERADE_help(void)
+{
+       printf(
+"MASQUERADE target options:\n"
+" --to-ports <port>[-<port>]\n"
+"                              Port (range) to map to.\n"
+" --random\n"
+"                              Randomize source port.\n");
+}
+
+static const struct option MASQUERADE_opts[] = {
+       { "to-ports", 1, NULL, '1' },
+       { "random", 0, NULL, '2' },
+       { .name = NULL }
+};
+
+/* Initialize the target. */
+static void MASQUERADE_init(struct xt_entry_target *t)
+{
+       struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data;
+
+       /* Actually, it's 0, but it's ignored at the moment. */
+       mr->rangesize = 1;
+
+}
+
+/* Parses ports */
+static void
+parse_ports(const char *arg, struct ip_nat_multi_range *mr)
+{
+       const char *dash;
+       int port;
+
+       mr->range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+
+       port = atoi(arg);
+       if (port <= 0 || port > 65535)
+               exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);
+
+       dash = strchr(arg, '-');
+       if (!dash) {
+               mr->range[0].min.tcp.port
+                       = mr->range[0].max.tcp.port
+                       = htons(port);
+       } else {
+               int maxport;
+
+               maxport = atoi(dash + 1);
+               if (maxport == 0 || maxport > 65535)
+                       exit_error(PARAMETER_PROBLEM,
+                                  "Port `%s' not valid\n", dash+1);
+               if (maxport < port)
+                       /* People are stupid.  Present reader excepted. */
+                       exit_error(PARAMETER_PROBLEM,
+                                  "Port range `%s' funky\n", arg);
+               mr->range[0].min.tcp.port = htons(port);
+               mr->range[0].max.tcp.port = htons(maxport);
+       }
+}
+
+/* Function which parses command options; returns true if it
+   ate an option */
+static int MASQUERADE_parse(int c, char **argv, int invert, unsigned int *flags,
+                            const void *e, struct xt_entry_target **target)
+{
+       const struct ipt_entry *entry = e;
+       int portok;
+       struct ip_nat_multi_range *mr
+               = (struct ip_nat_multi_range *)(*target)->data;
+
+       if (entry->ip.proto == IPPROTO_TCP
+           || entry->ip.proto == IPPROTO_UDP
+           || entry->ip.proto == IPPROTO_ICMP)
+               portok = 1;
+       else
+               portok = 0;
+
+       switch (c) {
+       case '1':
+               if (!portok)
+                       exit_error(PARAMETER_PROBLEM,
+                                  "Need TCP or UDP with port specification");
+
+               if (check_inverse(optarg, &invert, NULL, 0))
+                       exit_error(PARAMETER_PROBLEM,
+                                  "Unexpected `!' after --to-ports");
+
+               parse_ports(optarg, mr);
+               return 1;
+
+       case '2':
+               mr->range[0].flags |=  IP_NAT_RANGE_PROTO_RANDOM;
+               return 1;
+
+       default:
+               return 0;
+       }
+}
+
+/* Prints out the targinfo. */
+static void
+MASQUERADE_print(const void *ip, const struct xt_entry_target *target,
+                 int numeric)
+{
+       struct ip_nat_multi_range *mr
+               = (struct ip_nat_multi_range *)target->data;
+       struct ip_nat_range *r = &mr->range[0];
+
+       if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
+               printf("masq ports: ");
+               printf("%hu", ntohs(r->min.tcp.port));
+               if (r->max.tcp.port != r->min.tcp.port)
+                       printf("-%hu", ntohs(r->max.tcp.port));
+               printf(" ");
+       }
+
+       if (r->flags & IP_NAT_RANGE_PROTO_RANDOM)
+               printf("random ");
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+static void
+MASQUERADE_save(const void *ip, const struct xt_entry_target *target)
+{
+       struct ip_nat_multi_range *mr
+               = (struct ip_nat_multi_range *)target->data;
+       struct ip_nat_range *r = &mr->range[0];
+
+       if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
+               printf("--to-ports %hu", ntohs(r->min.tcp.port));
+               if (r->max.tcp.port != r->min.tcp.port)
+                       printf("-%hu", ntohs(r->max.tcp.port));
+               printf(" ");
+       }
+
+       if (r->flags & IP_NAT_RANGE_PROTO_RANDOM)
+               printf("--random ");
+}
+
+static struct xtables_target masquerade_tg_reg = {
+       .name           = "MASQUERADE",
+       .version        = XTABLES_VERSION,
+       .family         = PF_INET,
+       .size           = XT_ALIGN(sizeof(struct ip_nat_multi_range)),
+       .userspacesize  = XT_ALIGN(sizeof(struct ip_nat_multi_range)),
+       .help           = MASQUERADE_help,
+       .init           = MASQUERADE_init,
+       .parse          = MASQUERADE_parse,
+       .print          = MASQUERADE_print,
+       .save           = MASQUERADE_save,
+       .extra_opts     = MASQUERADE_opts,
+};
+
+void _init(void)
+{
+       xtables_register_target(&masquerade_tg_reg);
+}