Patch-o-matic! now included.
diff --git a/extensions/libipt_esp.c b/extensions/libipt_esp.c
new file mode 100644
index 0000000..d60c2a6
--- /dev/null
+++ b/extensions/libipt_esp.c
@@ -0,0 +1,191 @@
+/* Shared library add-on to iptables to add ESP support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <errno.h>
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ipt_esp.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+ printf(
+"ESP v%s options:\n"
+" --espspi [!] spi[:spi]\n"
+" match spi (range)\n",
+NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+ { "espspi", 1, 0, '1' },
+ {0}
+};
+
+static u_int32_t
+parse_esp_spi(const char *spistr)
+{
+ unsigned long int spi;
+ char* ep;
+
+ spi = strtoul(spistr,&ep,0) ;
+
+ if ( spistr == ep ) {
+ exit_error(PARAMETER_PROBLEM,
+ "ESP no valid digits in spi `%s'", spistr);
+ }
+ if ( spi == ULONG_MAX && errno == ERANGE ) {
+ exit_error(PARAMETER_PROBLEM,
+ "spi `%s' specified too big: would overflow", spistr);
+ }
+ if ( *spistr != '\0' && *ep != '\0' ) {
+ exit_error(PARAMETER_PROBLEM,
+ "ESP error parsing spi `%s'", spistr);
+ }
+ return (u_int32_t) spi;
+}
+
+static void
+parse_esp_spis(const char *spistring, u_int32_t *spis)
+{
+ char *buffer;
+ char *cp;
+
+ buffer = strdup(spistring);
+ if ((cp = strchr(buffer, ':')) == NULL)
+ spis[0] = spis[1] = parse_esp_spi(buffer);
+ else {
+ *cp = '\0';
+ cp++;
+
+ spis[0] = buffer[0] ? parse_esp_spi(buffer) : 0;
+ spis[1] = cp[0] ? parse_esp_spi(cp) : 0xFFFFFFFF;
+ }
+ free(buffer);
+}
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+ struct ipt_esp *espinfo = (struct ipt_esp *)m->data;
+
+ espinfo->spis[1] = 0xFFFFFFFF;
+}
+
+#define ESP_SPI 0x01
+
+/* Function which parses command options; returns true if it
+ ate an option */
+static int
+parse(int c, char **argv, int invert, unsigned int *flags,
+ const struct ipt_entry *entry,
+ unsigned int *nfcache,
+ struct ipt_entry_match **match)
+{
+ struct ipt_esp *espinfo = (struct ipt_esp *)(*match)->data;
+
+ switch (c) {
+ case '1':
+ if (*flags & ESP_SPI)
+ exit_error(PARAMETER_PROBLEM,
+ "Only one `--spi' allowed");
+ if (check_inverse(optarg, &invert))
+ optind++;
+ parse_esp_spis(argv[optind-1], espinfo->spis);
+ if (invert)
+ espinfo->invflags |= IPT_ESP_INV_SPI;
+ *flags |= ESP_SPI;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Final check; we don't care. */
+static void
+final_check(unsigned int flags)
+{
+}
+
+static void
+print_spis(const char *name, u_int32_t min, u_int32_t max,
+ int invert)
+{
+ const char *inv = invert ? "!" : "";
+
+ if (min != 0 || max != 0xFFFFFFFF || invert) {
+ printf("%s", name);
+ if (min == max) {
+ printf(":%s", inv);
+ printf("%u", min);
+ } else {
+ printf("s:%s", inv);
+ printf("%u",min);
+ printf(":");
+ printf("%u",max);
+ }
+ printf(" ");
+ }
+}
+
+/* Prints out the union ipt_matchinfo. */
+static void
+print(const struct ipt_ip *ip,
+ const struct ipt_entry_match *match, int numeric)
+{
+ const struct ipt_esp *esp = (struct ipt_esp *)match->data;
+
+ printf("esp ");
+ print_spis("spi", esp->spis[0], esp->spis[1],
+ esp->invflags & IPT_ESP_INV_SPI);
+ if (esp->invflags & ~IPT_ESP_INV_MASK)
+ printf("Unknown invflags: 0x%X ",
+ esp->invflags & ~IPT_ESP_INV_MASK);
+}
+
+/* Saves the union ipt_matchinfo in parsable form to stdout. */
+static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+ const struct ipt_esp *espinfo = (struct ipt_esp *)match->data;
+
+ if (espinfo->spis[0] != 0
+ && espinfo->spis[1] != 0xFFFFFFFF) {
+ if (espinfo->invflags & IPT_ESP_INV_SPI)
+ printf("! ");
+ if (espinfo->spis[0]
+ != espinfo->spis[1])
+ printf("--spi %u-%u ",
+ espinfo->spis[0],
+ espinfo->spis[1]);
+ else
+ printf("--spi %u ",
+ espinfo->spis[0]);
+ }
+
+}
+
+struct iptables_match esp
+= { NULL,
+ "esp",
+ NETFILTER_VERSION,
+ IPT_ALIGN(sizeof(struct ipt_esp)),
+ IPT_ALIGN(sizeof(struct ipt_esp)),
+ &help,
+ &init,
+ &parse,
+ &final_check,
+ &print,
+ &save,
+ opts
+};
+
+void
+_init(void)
+{
+ register_match(&esp);
+}