patch-2.4.18 linux/net/ipv4/netfilter/ipt_esp.c

• Lines: 106
• Date: Mon Feb 4 16:43:43 2002
• Orig file: linux.orig/net/ipv4/netfilter/ipt_esp.c
• Orig date: Thu Jan 1 00:00:00 1970

diff -Naur -X /home/marcelo/lib/dontdiff linux.orig/net/ipv4/netfilter/ipt_esp.c linux/net/ipv4/netfilter/ipt_esp.c
@@ -0,0 +1,105 @@
+/* Kernel module to match ESP parameters. */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter_ipv4/ipt_esp.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+EXPORT_NO_SYMBOLS;
+MODULE_LICENSE("GPL");
+
+#ifdef DEBUG_CONNTRACK
+#define duprintf(format, args...) printk(format , ## args)
+#else
+#define duprintf(format, args...)
+#endif
+
+struct esphdr {
+	__u32   spi;
+};
+
+/* Returns 1 if the spi is matched by the range, 0 otherwise */
+static inline int
+spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
+{
+	int r=0;
+        duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
+        	min,spi,max);
+	r=(spi >= min && spi <= max) ^ invert;
+	duprintf(" result %s\n",r? "PASS" : "FAILED");
+	return r;
+}
+
+static int
+match(const struct sk_buff *skb,
+      const struct net_device *in,
+      const struct net_device *out,
+      const void *matchinfo,
+      int offset,
+      const void *hdr,
+      u_int16_t datalen,
+      int *hotdrop)
+{
+	const struct esphdr *esp = hdr;
+	const struct ipt_esp *espinfo = matchinfo;
+
+	if (offset == 0 && datalen < sizeof(struct esphdr)) {
+		/* We've been asked to examine this packet, and we
+		   can't.  Hence, no choice but to drop. */
+		duprintf("Dropping evil ESP tinygram.\n");
+		*hotdrop = 1;
+		return 0;
+	}
+
+	/* Must not be a fragment. */
+	return !offset
+		&& spi_match(espinfo->spis[0], espinfo->spis[1],
+			      ntohl(esp->spi),
+			      !!(espinfo->invflags & IPT_ESP_INV_SPI));
+}
+
+/* Called when user tries to insert an entry of this type. */
+static int
+checkentry(const char *tablename,
+	   const struct ipt_ip *ip,
+	   void *matchinfo,
+	   unsigned int matchinfosize,
+	   unsigned int hook_mask)
+{
+	const struct ipt_esp *espinfo = matchinfo;
+
+	/* Must specify proto == ESP, and no unknown invflags */
+	if (ip->proto != IPPROTO_ESP || (ip->invflags & IPT_INV_PROTO)) {
+		duprintf("ipt_esp: Protocol %u != %u\n", ip->proto,
+			 IPPROTO_ESP);
+		return 0;
+	}
+	if (matchinfosize != IPT_ALIGN(sizeof(struct ipt_esp))) {
+		duprintf("ipt_esp: matchsize %u != %u\n",
+			 matchinfosize, IPT_ALIGN(sizeof(struct ipt_esp)));
+		return 0;
+	}
+	if (espinfo->invflags & ~IPT_ESP_INV_MASK) {
+		duprintf("ipt_esp: unknown flags %X\n",
+			 espinfo->invflags);
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct ipt_match esp_match
+= { { NULL, NULL }, "esp", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+	return ipt_register_match(&esp_match);
+}
+
+static void __exit cleanup(void)
+{
+	ipt_unregister_match(&esp_match);
+}
+
+module_init(init);
+module_exit(cleanup);