patch-2.4.21 linux-2.4.21/net/ipv6/netfilter/ip6t_esp.c

• Lines: 176
• Date: 2003-06-13 07:51:39.000000000 -0700
• Orig file: linux-2.4.20/net/ipv6/netfilter/ip6t_esp.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/net/ipv6/netfilter/ip6t_esp.c linux-2.4.21/net/ipv6/netfilter/ip6t_esp.c
@@ -0,0 +1,175 @@
+/* Kernel module to match ESP parameters. */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ipv6.h>
+#include <linux/types.h>
+#include <net/checksum.h>
+#include <net/ipv6.h>
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_esp.h>
+
+EXPORT_NO_SYMBOLS;
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IPv6 ESP match");
+MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(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;
+        DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
+        	min,spi,max);
+	r=(spi >= min && spi <= max) ^ invert;
+	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
+	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 *protohdr,
+      u_int16_t datalen,
+      int *hotdrop)
+{
+	struct esphdr *esp = NULL;
+	const struct ip6t_esp *espinfo = matchinfo;
+	unsigned int temp;
+	int len;
+	u8 nexthdr;
+	unsigned int ptr;
+
+	/* Make sure this isn't an evil packet */
+	/*DEBUGP("ipv6_esp entered \n");*/
+
+	/* type of the 1st exthdr */
+	nexthdr = skb->nh.ipv6h->nexthdr;
+	/* pointer to the 1st exthdr */
+	ptr = sizeof(struct ipv6hdr);
+	/* available length */
+	len = skb->len - ptr;
+	temp = 0;
+
+        while (ip6t_ext_hdr(nexthdr)) {
+        	struct ipv6_opt_hdr *hdr;
+        	int hdrlen;
+
+		DEBUGP("ipv6_esp header iteration \n");
+
+		/* Is there enough space for the next ext header? */
+                if (len < (int)sizeof(struct ipv6_opt_hdr))
+                        return 0;
+		/* No more exthdr -> evaluate */
+                if (nexthdr == NEXTHDR_NONE) {
+			break;
+		}
+		/* ESP -> evaluate */
+                if (nexthdr == NEXTHDR_ESP) {
+			temp |= MASK_ESP;
+			break;
+		}
+
+		hdr=(struct ipv6_opt_hdr *)skb->data+ptr;
+
+		/* Calculate the header length */
+                if (nexthdr == NEXTHDR_FRAGMENT) {
+                        hdrlen = 8;
+                } else if (nexthdr == NEXTHDR_AUTH)
+                        hdrlen = (hdr->hdrlen+2)<<2;
+                else
+                        hdrlen = ipv6_optlen(hdr);
+
+		/* set the flag */
+		switch (nexthdr){
+			case NEXTHDR_HOP:
+			case NEXTHDR_ROUTING:
+			case NEXTHDR_FRAGMENT:
+			case NEXTHDR_AUTH:
+			case NEXTHDR_DEST:
+				break;
+			default:
+				DEBUGP("ipv6_esp match: unknown nextheader %u\n",nexthdr);
+				return 0;
+				break;
+		}
+
+                nexthdr = hdr->nexthdr;
+                len -= hdrlen;
+                ptr += hdrlen;
+		if ( ptr > skb->len ) {
+			DEBUGP("ipv6_esp: new pointer too large! \n");
+			break;
+		}
+        }
+
+	/* ESP header not found */
+	if ( temp != MASK_ESP ) return 0;
+
+       if (len < (int)sizeof(struct esphdr)){
+	       *hotdrop = 1;
+       		return 0;
+       }
+
+	esp=skb->data+ptr;
+
+	DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(esp->spi), ntohl(esp->spi));
+
+	return (esp != NULL)
+		&& spi_match(espinfo->spis[0], espinfo->spis[1],
+			      ntohl(esp->spi),
+			      !!(espinfo->invflags & IP6T_ESP_INV_SPI));
+}
+
+/* Called when user tries to insert an entry of this type. */
+static int
+checkentry(const char *tablename,
+	   const struct ip6t_ip6 *ip,
+	   void *matchinfo,
+	   unsigned int matchinfosize,
+	   unsigned int hook_mask)
+{
+	const struct ip6t_esp *espinfo = matchinfo;
+
+	if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_esp))) {
+		DEBUGP("ip6t_esp: matchsize %u != %u\n",
+			 matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_esp)));
+		return 0;
+	}
+	if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {
+		DEBUGP("ip6t_esp: unknown flags %X\n",
+			 espinfo->invflags);
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct ip6t_match esp_match
+= { { NULL, NULL }, "esp", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+	return ip6t_register_match(&esp_match);
+}
+
+static void __exit cleanup(void)
+{
+	ip6t_unregister_match(&esp_match);
+}
+
+module_init(init);
+module_exit(cleanup);