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Commit 067b207b authored by James Chapman's avatar James Chapman Committed by David S. Miller
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[UDP]: Cleanup UDP encapsulation code 



This cleanup fell out after adding L2TP support where a new encap_rcv
funcptr was added to struct udp_sock. Have XFRM use the new encap_rcv
funcptr, which allows us to move the XFRM encap code from udp.c into
xfrm4_input.c.

Make xfrm4_rcv_encap() static since it is no longer called externally.

Signed-off-by: default avatarJames Chapman <jchapman@katalix.com>
Acked-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 93cce3d3

include/net/xfrm.h

+3 −2
Original line number Diff line number Diff line
@@ -1003,7 +1003,7 @@ extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, 
				 u8 **prevhdr);



#ifdef CONFIG_XFRM

extern int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type);

extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);

extern int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen);

extern int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl, unsigned short family);

#else
@@ -1012,12 +1012,13 @@ static inline int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optv 
 	return -ENOPROTOOPT;

} 



static inline int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)

static inline int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)

{

 	/* should not happen */

 	kfree_skb(skb);

	return 0;

}



static inline int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl, unsigned short family)

{

	return -EINVAL;

net/ipv4/udp.c

+24 −132
Original line number Diff line number Diff line
@@ -920,108 +920,6 @@ int udp_disconnect(struct sock *sk, int flags) 
	return 0;

}



/* return:

 * 	1  if the UDP system should process it

 *	0  if we should drop this packet

 * 	-1 if it should get processed by xfrm4_rcv_encap

 *	-2 if it should get processed by l2tp

 */

static int 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 we're overly short, let UDP handle it */

	len = skb->len - sizeof(struct udphdr);

	if (len <= 0)

		return 1;



	/* 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. */

	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) {

			return 0;

		} 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) {

			return 0;

		} 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;

	case UDP_ENCAP_L2TPINUDP:

		/* Let caller know to send this to l2tp */

		return -2;

	}



#ifndef CONFIG_XFRM

	return 1;

#else

	/* 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_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))

		return 0;



	/* 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!?! */

		return 0;

	}



	/* 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);



	/* modify the protocol (it's ESP!) */

	iph->protocol = IPPROTO_ESP;



	/* and let the caller know to send this into the ESP processor... */

	return -1;

#endif

}



/* returns:

 *  -1: error

 *   0: success
@@ -1044,44 +942,36 @@ int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb) 


	if (up->encap_type) {

		/*

		 * This is an encapsulation socket, so let's see if this is

		 * an encapsulated packet.

		 * If it's a keepalive packet, then just eat it.

		 * If it's an encapsulateed packet, then pass it to the

		 * IPsec xfrm input and return the response

		 * appropriately.  Otherwise, just fall through and

		 * pass this up the UDP socket.

		 * This is an encapsulation socket so pass the skb to

		 * the socket's udp_encap_rcv() hook. Otherwise, just

		 * fall through and pass this up the UDP socket.

		 * up->encap_rcv() returns the following value:

		 * =0 if skb was successfully passed to the encap

		 *    handler or was discarded by it.

		 * >0 if skb should be passed on to UDP.

		 * <0 if skb should be resubmitted as proto -N

		 */

		int ret;

		unsigned int len;



		/* if we're overly short, let UDP handle it */

		len = skb->len - sizeof(struct udphdr);

		if (len <= 0)

			goto udp;



		ret = udp_encap_rcv(sk, skb);

		if (ret == 0) {

			/* Eat the packet .. */

			kfree_skb(skb);

			return 0;

		}

		if (ret == -1) {

			/* process the ESP packet */

			ret = xfrm4_rcv_encap(skb, up->encap_type);

			UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);

			return -ret;

		}

		if (ret == -2) {

			/* process the L2TP packet */

		if (up->encap_rcv != NULL) {

			int ret;



			ret = (*up->encap_rcv)(sk, skb);

			if (ret <= 0) {

				UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);

					return ret;

				}



				/* FALLTHROUGH -- pass up as UDP packet */

				return -ret;

			}

		}



		/* FALLTHROUGH -- it's a UDP Packet */

	}



udp:

	/*

	 * 	UDP-Lite specific tests, ignored on UDP sockets

	 */
@@ -1367,6 +1257,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, 
		case 0:

		case UDP_ENCAP_ESPINUDP:

		case UDP_ENCAP_ESPINUDP_NON_IKE:

			up->encap_rcv = xfrm4_udp_encap_rcv;

			/* FALLTHROUGH */

		case UDP_ENCAP_L2TPINUDP:

			up->encap_type = val;

			break;

net/ipv4/xfrm4_input.c

+106 −8
Original line number Diff line number Diff line
@@ -16,13 +16,6 @@ 
#include <net/ip.h>

#include <net/xfrm.h>



int xfrm4_rcv(struct sk_buff *skb)

{

	return xfrm4_rcv_encap(skb, 0);

}



EXPORT_SYMBOL(xfrm4_rcv);



static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)

{

	switch (nexthdr) {
@@ -53,7 +46,7 @@ static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) 
}

#endif



int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)

static int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)

{

	__be32 spi, seq;

	struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
@@ -167,3 +160,108 @@ int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) 
	kfree_skb(skb);

	return 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;

	int ret;



	__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;

		} 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;

		} 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;

	}



	/* 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_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))

		goto drop;



	/* 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;

	}



	/* 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);



	/* modify the protocol (it's ESP!) */

	iph->protocol = IPPROTO_ESP;



	/* process ESP */

	ret = xfrm4_rcv_encap(skb, encap_type);

	return ret;



drop:

	kfree_skb(skb);

	return 0;

}



int xfrm4_rcv(struct sk_buff *skb)

{

	return xfrm4_rcv_encap(skb, 0);

}



EXPORT_SYMBOL(xfrm4_rcv);