1 files changed, 109 insertions, 120 deletions

diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 8655d038364..aac6197b7a7 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -6,9 +6,10 @@
  *		Split up af-specific portion
  *	Derek Atkins <derek@ihtfp.com>
  *		Add Encapsulation support
- * 	
+ *
  */
 
+#include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/string.h>
 #include <linux/netfilter.h>
@@ -16,33 +17,18 @@
 #include <net/ip.h>
 #include <net/xfrm.h>
 
-int xfrm4_rcv(struct sk_buff *skb)
+int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
 {
-	return xfrm4_rcv_encap(skb, 0);
+	return xfrm4_extract_header(skb);
 }
 
-EXPORT_SYMBOL(xfrm4_rcv);
-
-static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
-{
-	switch (nexthdr) {
-	case IPPROTO_IPIP:
-		*spi = skb->nh.iph->saddr;
-		*seq = 0;
-		return 0;
-	}
-
-	return xfrm_parse_spi(skb, nexthdr, spi, seq);
-}
-
-#ifdef CONFIG_NETFILTER
 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
 {
-	struct iphdr *iph = skb->nh.iph;
+	if (skb_dst(skb) == NULL) {
+		const struct iphdr *iph = ip_hdr(skb);
 
-	if (skb->dst == NULL) {
-		if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
-		                   skb->dev))
+		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
+					 iph->tos, skb->dev))
 			goto drop;
 	}
 	return dst_input(skb);
@@ -50,119 +36,122 @@ drop:
 	kfree_skb(skb);
 	return NET_RX_DROP;
 }
-#endif
 
-int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
+int xfrm4_transport_finish(struct sk_buff *skb, int async)
 {
-	int err;
-	__be32 spi, seq;
-	struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
-	struct xfrm_state *x;
-	int xfrm_nr = 0;
-	int decaps = 0;
-
-	if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
-		goto drop;
-
-	do {
-		struct iphdr *iph = skb->nh.iph;
-
-		if (xfrm_nr == XFRM_MAX_DEPTH)
-			goto drop;
-
-		x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
-		if (x == NULL)
-			goto drop;
-
-		spin_lock(&x->lock);
-		if (unlikely(x->km.state != XFRM_STATE_VALID))
-			goto drop_unlock;
-
-		if ((x->encap ? x->encap->encap_type : 0) != encap_type)
-			goto drop_unlock;
-
-		if (x->props.replay_window && xfrm_replay_check(x, seq))
-			goto drop_unlock;
-
-		if (xfrm_state_check_expire(x))
-			goto drop_unlock;
-
-		if (x->type->input(x, skb))
-			goto drop_unlock;
-
-		/* only the first xfrm gets the encap type */
-		encap_type = 0;
+	struct iphdr *iph = ip_hdr(skb);
 
-		if (x->props.replay_window)
-			xfrm_replay_advance(x, seq);
+	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
 
-		x->curlft.bytes += skb->len;
-		x->curlft.packets++;
-
-		spin_unlock(&x->lock);
-
-		xfrm_vec[xfrm_nr++] = x;
+#ifndef CONFIG_NETFILTER
+	if (!async)
+		return -iph->protocol;
+#endif
 
-		if (x->mode->input(x, skb))
-			goto drop;
+	__skb_push(skb, skb->data - skb_network_header(skb));
+	iph->tot_len = htons(skb->len);
+	ip_send_check(iph);
 
-		if (x->props.mode == XFRM_MODE_TUNNEL) {
-			decaps = 1;
-			break;
-		}
+	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
+		xfrm4_rcv_encap_finish);
+	return 0;
+}
 
-		if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0)
+/* If it's a keepalive packet, then just eat it.
+ * If it's an encapsulated packet, then pass it to the
+ * IPsec xfrm input.
+ * Returns 0 if skb passed to xfrm or was dropped.
+ * Returns >0 if skb should be passed to UDP.
+ * Returns <0 if skb should be resubmitted (-ret is protocol)
+ */
+int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct udp_sock *up = udp_sk(sk);
+	struct udphdr *uh;
+	struct iphdr *iph;
+	int iphlen, len;
+
+	__u8 *udpdata;
+	__be32 *udpdata32;
+	__u16 encap_type = up->encap_type;
+
+	/* if this is not encapsulated socket, then just return now */
+	if (!encap_type)
+		return 1;
+
+	/* If this is a paged skb, make sure we pull up
+	 * whatever data we need to look at. */
+	len = skb->len - sizeof(struct udphdr);
+	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
+		return 1;
+
+	/* Now we can get the pointers */
+	uh = udp_hdr(skb);
+	udpdata = (__u8 *)uh + sizeof(struct udphdr);
+	udpdata32 = (__be32 *)udpdata;
+
+	switch (encap_type) {
+	default:
+	case UDP_ENCAP_ESPINUDP:
+		/* Check if this is a keepalive packet.  If so, eat it. */
+		if (len == 1 && udpdata[0] == 0xff) {
 			goto drop;
-	} while (!err);
-
-	/* Allocate new secpath or COW existing one. */
-
-	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
-		struct sec_path *sp;
-		sp = secpath_dup(skb->sp);
-		if (!sp)
+		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
+			/* ESP Packet without Non-ESP header */
+			len = sizeof(struct udphdr);
+		} else
+			/* Must be an IKE packet.. pass it through */
+			return 1;
+		break;
+	case UDP_ENCAP_ESPINUDP_NON_IKE:
+		/* Check if this is a keepalive packet.  If so, eat it. */
+		if (len == 1 && udpdata[0] == 0xff) {
 			goto drop;
-		if (skb->sp)
-			secpath_put(skb->sp);
-		skb->sp = sp;
+		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
+			   udpdata32[0] == 0 && udpdata32[1] == 0) {
+
+			/* ESP Packet with Non-IKE marker */
+			len = sizeof(struct udphdr) + 2 * sizeof(u32);
+		} else
+			/* Must be an IKE packet.. pass it through */
+			return 1;
+		break;
 	}
-	if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
+
+	/* At this point we are sure that this is an ESPinUDP packet,
+	 * so we need to remove 'len' bytes from the packet (the UDP
+	 * header and optional ESP marker bytes) and then modify the
+	 * protocol to ESP, and then call into the transform receiver.
+	 */
+	if (skb_unclone(skb, GFP_ATOMIC))
 		goto drop;
 
-	memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
-	       xfrm_nr * sizeof(xfrm_vec[0]));
-	skb->sp->len += xfrm_nr;
-
-	nf_reset(skb);
-
-	if (decaps) {
-		if (!(skb->dev->flags&IFF_LOOPBACK)) {
-			dst_release(skb->dst);
-			skb->dst = NULL;
-		}
-		netif_rx(skb);
-		return 0;
-	} else {
-#ifdef CONFIG_NETFILTER
-		__skb_push(skb, skb->data - skb->nh.raw);
-		skb->nh.iph->tot_len = htons(skb->len);
-		ip_send_check(skb->nh.iph);
-
-		NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
-		        xfrm4_rcv_encap_finish);
-		return 0;
-#else
-		return -skb->nh.iph->protocol;
-#endif
+	/* Now we can update and verify the packet length... */
+	iph = ip_hdr(skb);
+	iphlen = iph->ihl << 2;
+	iph->tot_len = htons(ntohs(iph->tot_len) - len);
+	if (skb->len < iphlen + len) {
+		/* packet is too small!?! */
+		goto drop;
 	}
 
-drop_unlock:
-	spin_unlock(&x->lock);
-	xfrm_state_put(x);
-drop:
-	while (--xfrm_nr >= 0)
-		xfrm_state_put(xfrm_vec[xfrm_nr]);
+	/* pull the data buffer up to the ESP header and set the
+	 * transport header to point to ESP.  Keep UDP on the stack
+	 * for later.
+	 */
+	__skb_pull(skb, len);
+	skb_reset_transport_header(skb);
 
+	/* process ESP */
+	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
+
+drop:
 	kfree_skb(skb);
 	return 0;
 }
+
+int xfrm4_rcv(struct sk_buff *skb)
+{
+	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
+}
+EXPORT_SYMBOL(xfrm4_rcv);