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Commit 9f57c67c authored by Pravin B Shelar's avatar Pravin B Shelar Committed by David S. Miller
Browse files

gre: Remove support for sharing GRE protocol hook. 



Support for sharing GREPROTO_CISCO port was added so that
OVS gre port and kernel GRE devices can co-exist. After
flow-based tunneling patches OVS GRE protocol processing
is completely moved to ip_gre module. so there is no need
for GRE protocol hook. Following patch consolidates
GRE protocol related functions into ip_gre module.

Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
Acked-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b2acd1dc

include/net/gre.h

+6 −74
Original line number Diff line number Diff line
@@ -4,6 +4,12 @@ 
#include <linux/skbuff.h>

#include <net/ip_tunnels.h>



struct gre_base_hdr {

	__be16 flags;

	__be16 protocol;

};

#define GRE_HEADER_SECTION 4



#define GREPROTO_CISCO		0

#define GREPROTO_PPTP		1

#define GREPROTO_MAX		2
@@ -14,83 +20,9 @@ struct gre_protocol { 
	void (*err_handler)(struct sk_buff *skb, u32 info);

};



struct gre_base_hdr {

	__be16 flags;

	__be16 protocol;

};

#define GRE_HEADER_SECTION 4



int gre_add_protocol(const struct gre_protocol *proto, u8 version);

int gre_del_protocol(const struct gre_protocol *proto, u8 version);



struct gre_cisco_protocol {

	int (*handler)(struct sk_buff *skb, const struct tnl_ptk_info *tpi);

	int (*err_handler)(struct sk_buff *skb, u32 info,

			   const struct tnl_ptk_info *tpi);

	u8 priority;

};



int gre_cisco_register(struct gre_cisco_protocol *proto);

int gre_cisco_unregister(struct gre_cisco_protocol *proto);



struct net_device *gretap_fb_dev_create(struct net *net, const char *name,

				       u8 name_assign_type);



static inline int ip_gre_calc_hlen(__be16 o_flags)

{

	int addend = 4;



	if (o_flags&TUNNEL_CSUM)

		addend += 4;

	if (o_flags&TUNNEL_KEY)

		addend += 4;

	if (o_flags&TUNNEL_SEQ)

		addend += 4;

	return addend;

}



static inline __be16 gre_flags_to_tnl_flags(__be16 flags)

{

	__be16 tflags = 0;



	if (flags & GRE_CSUM)

		tflags |= TUNNEL_CSUM;

	if (flags & GRE_ROUTING)

		tflags |= TUNNEL_ROUTING;

	if (flags & GRE_KEY)

		tflags |= TUNNEL_KEY;

	if (flags & GRE_SEQ)

		tflags |= TUNNEL_SEQ;

	if (flags & GRE_STRICT)

		tflags |= TUNNEL_STRICT;

	if (flags & GRE_REC)

		tflags |= TUNNEL_REC;

	if (flags & GRE_VERSION)

		tflags |= TUNNEL_VERSION;



	return tflags;

}



static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)

{

	__be16 flags = 0;



	if (tflags & TUNNEL_CSUM)

		flags |= GRE_CSUM;

	if (tflags & TUNNEL_ROUTING)

		flags |= GRE_ROUTING;

	if (tflags & TUNNEL_KEY)

		flags |= GRE_KEY;

	if (tflags & TUNNEL_SEQ)

		flags |= GRE_SEQ;

	if (tflags & TUNNEL_STRICT)

		flags |= GRE_STRICT;

	if (tflags & TUNNEL_REC)

		flags |= GRE_REC;

	if (tflags & TUNNEL_VERSION)

		flags |= GRE_VERSION;



	return flags;

}



#endif

net/ipv4/gre_demux.c

+1 −200
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#include <net/xfrm.h>



static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;

static struct gre_cisco_protocol __rcu *gre_cisco_proto_list[GRE_IP_PROTO_MAX];



int gre_add_protocol(const struct gre_protocol *proto, u8 version)

{
@@ -61,163 +60,6 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version) 
}

EXPORT_SYMBOL_GPL(gre_del_protocol);



static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,

			    bool *csum_err)

{

	const struct gre_base_hdr *greh;

	__be32 *options;

	int hdr_len;



	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))

		return -EINVAL;



	greh = (struct gre_base_hdr *)skb_transport_header(skb);

	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))

		return -EINVAL;



	tpi->flags = gre_flags_to_tnl_flags(greh->flags);

	hdr_len = ip_gre_calc_hlen(tpi->flags);



	if (!pskb_may_pull(skb, hdr_len))

		return -EINVAL;



	greh = (struct gre_base_hdr *)skb_transport_header(skb);

	tpi->proto = greh->protocol;



	options = (__be32 *)(greh + 1);

	if (greh->flags & GRE_CSUM) {

		if (skb_checksum_simple_validate(skb)) {

			*csum_err = true;

			return -EINVAL;

		}



		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,

					 null_compute_pseudo);



		options++;

	}



	if (greh->flags & GRE_KEY) {

		tpi->key = *options;

		options++;

	} else

		tpi->key = 0;



	if (unlikely(greh->flags & GRE_SEQ)) {

		tpi->seq = *options;

		options++;

	} else

		tpi->seq = 0;



	/* WCCP version 1 and 2 protocol decoding.

	 * - Change protocol to IP

	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header

	 */

	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {

		tpi->proto = htons(ETH_P_IP);

		if ((*(u8 *)options & 0xF0) != 0x40) {

			hdr_len += 4;

			if (!pskb_may_pull(skb, hdr_len))

				return -EINVAL;

		}

	}



	return iptunnel_pull_header(skb, hdr_len, tpi->proto);

}



static int gre_cisco_rcv(struct sk_buff *skb)

{

	struct tnl_ptk_info tpi;

	int i;

	bool csum_err = false;



#ifdef CONFIG_NET_IPGRE_BROADCAST

	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {

		/* Looped back packet, drop it! */

		if (rt_is_output_route(skb_rtable(skb)))

			goto drop;

	}

#endif



	if (parse_gre_header(skb, &tpi, &csum_err) < 0)

		goto drop;



	rcu_read_lock();

	for (i = 0; i < GRE_IP_PROTO_MAX; i++) {

		struct gre_cisco_protocol *proto;

		int ret;



		proto = rcu_dereference(gre_cisco_proto_list[i]);

		if (!proto)

			continue;

		ret = proto->handler(skb, &tpi);

		if (ret == PACKET_RCVD) {

			rcu_read_unlock();

			return 0;

		}

	}

	rcu_read_unlock();



	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

drop:

	kfree_skb(skb);

	return 0;

}



static void gre_cisco_err(struct sk_buff *skb, u32 info)

{

	/* All the routers (except for Linux) return only

	 * 8 bytes of packet payload. It means, that precise relaying of

	 * ICMP in the real Internet is absolutely infeasible.

	 *

	 * Moreover, Cisco "wise men" put GRE key to the third word

	 * in GRE header. It makes impossible maintaining even soft

	 * state for keyed

	 * GRE tunnels with enabled checksum. Tell them "thank you".

	 *

	 * Well, I wonder, rfc1812 was written by Cisco employee,

	 * what the hell these idiots break standards established

	 * by themselves???

	 */



	const int type = icmp_hdr(skb)->type;

	const int code = icmp_hdr(skb)->code;

	struct tnl_ptk_info tpi;

	bool csum_err = false;

	int i;



	if (parse_gre_header(skb, &tpi, &csum_err)) {

		if (!csum_err)		/* ignore csum errors. */

			return;

	}



	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {

		ipv4_update_pmtu(skb, dev_net(skb->dev), info,

				skb->dev->ifindex, 0, IPPROTO_GRE, 0);

		return;

	}

	if (type == ICMP_REDIRECT) {

		ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,

				IPPROTO_GRE, 0);

		return;

	}



	rcu_read_lock();

	for (i = 0; i < GRE_IP_PROTO_MAX; i++) {

		struct gre_cisco_protocol *proto;



		proto = rcu_dereference(gre_cisco_proto_list[i]);

		if (!proto)

			continue;



		if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD)

			goto out;



	}

out:

	rcu_read_unlock();

}



static int gre_rcv(struct sk_buff *skb)

{

	const struct gre_protocol *proto;
@@ -268,60 +110,19 @@ static const struct net_protocol net_gre_protocol = { 
	.netns_ok    = 1,

};



static const struct gre_protocol ipgre_protocol = {

	.handler     = gre_cisco_rcv,

	.err_handler = gre_cisco_err,

};



int gre_cisco_register(struct gre_cisco_protocol *newp)

{

	struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)

					    &gre_cisco_proto_list[newp->priority];



	return (cmpxchg(proto, NULL, newp) == NULL) ? 0 : -EBUSY;

}

EXPORT_SYMBOL_GPL(gre_cisco_register);



int gre_cisco_unregister(struct gre_cisco_protocol *del_proto)

{

	struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)

					    &gre_cisco_proto_list[del_proto->priority];

	int ret;



	ret = (cmpxchg(proto, del_proto, NULL) == del_proto) ? 0 : -EINVAL;



	if (ret)

		return ret;



	synchronize_net();

	return 0;

}

EXPORT_SYMBOL_GPL(gre_cisco_unregister);



static int __init gre_init(void)

{

	pr_info("GRE over IPv4 demultiplexor driver\n");



	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {

		pr_err("can't add protocol\n");

		goto err;

	}



	if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) {

		pr_info("%s: can't add ipgre handler\n", __func__);

		goto err_gre;

		return -EAGAIN;

	}



	return 0;

err_gre:

	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);

err:

	return -EAGAIN;

}



static void __exit gre_exit(void)

{

	gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);

	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);

}

net/ipv4/ip_gre.c

+199 −16
Original line number Diff line number Diff line
@@ -123,7 +123,126 @@ static int ipgre_tunnel_init(struct net_device *dev); 
static int ipgre_net_id __read_mostly;

static int gre_tap_net_id __read_mostly;



static int ipgre_err(struct sk_buff *skb, u32 info,

static int ip_gre_calc_hlen(__be16 o_flags)

{

	int addend = 4;



	if (o_flags & TUNNEL_CSUM)

		addend += 4;

	if (o_flags & TUNNEL_KEY)

		addend += 4;

	if (o_flags & TUNNEL_SEQ)

		addend += 4;

	return addend;

}



static __be16 gre_flags_to_tnl_flags(__be16 flags)

{

	__be16 tflags = 0;



	if (flags & GRE_CSUM)

		tflags |= TUNNEL_CSUM;

	if (flags & GRE_ROUTING)

		tflags |= TUNNEL_ROUTING;

	if (flags & GRE_KEY)

		tflags |= TUNNEL_KEY;

	if (flags & GRE_SEQ)

		tflags |= TUNNEL_SEQ;

	if (flags & GRE_STRICT)

		tflags |= TUNNEL_STRICT;

	if (flags & GRE_REC)

		tflags |= TUNNEL_REC;

	if (flags & GRE_VERSION)

		tflags |= TUNNEL_VERSION;



	return tflags;

}



static __be16 tnl_flags_to_gre_flags(__be16 tflags)

{

	__be16 flags = 0;



	if (tflags & TUNNEL_CSUM)

		flags |= GRE_CSUM;

	if (tflags & TUNNEL_ROUTING)

		flags |= GRE_ROUTING;

	if (tflags & TUNNEL_KEY)

		flags |= GRE_KEY;

	if (tflags & TUNNEL_SEQ)

		flags |= GRE_SEQ;

	if (tflags & TUNNEL_STRICT)

		flags |= GRE_STRICT;

	if (tflags & TUNNEL_REC)

		flags |= GRE_REC;

	if (tflags & TUNNEL_VERSION)

		flags |= GRE_VERSION;



	return flags;

}



static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,

			    bool *csum_err)

{

	const struct gre_base_hdr *greh;

	__be32 *options;

	int hdr_len;



	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))

		return -EINVAL;



	greh = (struct gre_base_hdr *)skb_transport_header(skb);

	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))

		return -EINVAL;



	tpi->flags = gre_flags_to_tnl_flags(greh->flags);

	hdr_len = ip_gre_calc_hlen(tpi->flags);



	if (!pskb_may_pull(skb, hdr_len))

		return -EINVAL;



	greh = (struct gre_base_hdr *)skb_transport_header(skb);

	tpi->proto = greh->protocol;



	options = (__be32 *)(greh + 1);

	if (greh->flags & GRE_CSUM) {

		if (skb_checksum_simple_validate(skb)) {

			*csum_err = true;

			return -EINVAL;

		}



		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,

					 null_compute_pseudo);

		options++;

	}



	if (greh->flags & GRE_KEY) {

		tpi->key = *options;

		options++;

	} else {

		tpi->key = 0;

	}

	if (unlikely(greh->flags & GRE_SEQ)) {

		tpi->seq = *options;

		options++;

	} else {

		tpi->seq = 0;

	}

	/* WCCP version 1 and 2 protocol decoding.

	 * - Change protocol to IP

	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header

	 */

	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {

		tpi->proto = htons(ETH_P_IP);

		if ((*(u8 *)options & 0xF0) != 0x40) {

			hdr_len += 4;

			if (!pskb_may_pull(skb, hdr_len))

				return -EINVAL;

		}

	}

	return iptunnel_pull_header(skb, hdr_len, tpi->proto);

}



static void ipgre_err(struct sk_buff *skb, u32 info,

		      const struct tnl_ptk_info *tpi)

{
@@ -150,14 +269,14 @@ static int ipgre_err(struct sk_buff *skb, u32 info, 
	switch (type) {

	default:

	case ICMP_PARAMETERPROB:

		return PACKET_RCVD;

		return;



	case ICMP_DEST_UNREACH:

		switch (code) {

		case ICMP_SR_FAILED:

		case ICMP_PORT_UNREACH:

			/* Impossible event. */

			return PACKET_RCVD;

			return;

		default:

			/* All others are translated to HOST_UNREACH.

			   rfc2003 contains "deep thoughts" about NET_UNREACH,
@@ -166,9 +285,10 @@ static int ipgre_err(struct sk_buff *skb, u32 info, 
			break;

		}

		break;



	case ICMP_TIME_EXCEEDED:

		if (code != ICMP_EXC_TTL)

			return PACKET_RCVD;

			return;

		break;



	case ICMP_REDIRECT:
@@ -185,21 +305,60 @@ static int ipgre_err(struct sk_buff *skb, u32 info, 
			     iph->daddr, iph->saddr, tpi->key);



	if (!t)

		return PACKET_REJECT;

		return;



	if (t->parms.iph.daddr == 0 ||

	    ipv4_is_multicast(t->parms.iph.daddr))

		return PACKET_RCVD;

		return;



	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)

		return PACKET_RCVD;

		return;



	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))

		t->err_count++;

	else

		t->err_count = 1;

	t->err_time = jiffies;

	return PACKET_RCVD;

}



static void gre_err(struct sk_buff *skb, u32 info)

{

	/* All the routers (except for Linux) return only

	 * 8 bytes of packet payload. It means, that precise relaying of

	 * ICMP in the real Internet is absolutely infeasible.

	 *

	 * Moreover, Cisco "wise men" put GRE key to the third word

	 * in GRE header. It makes impossible maintaining even soft

	 * state for keyed

	 * GRE tunnels with enabled checksum. Tell them "thank you".

	 *

	 * Well, I wonder, rfc1812 was written by Cisco employee,

	 * what the hell these idiots break standards established

	 * by themselves???

	 */



	const int type = icmp_hdr(skb)->type;

	const int code = icmp_hdr(skb)->code;

	struct tnl_ptk_info tpi;

	bool csum_err = false;



	if (parse_gre_header(skb, &tpi, &csum_err)) {

		if (!csum_err)		/* ignore csum errors. */

			return;

	}



	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {

		ipv4_update_pmtu(skb, dev_net(skb->dev), info,

				 skb->dev->ifindex, 0, IPPROTO_GRE, 0);

		return;

	}

	if (type == ICMP_REDIRECT) {

		ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,

			      IPPROTO_GRE, 0);

		return;

	}



	ipgre_err(skb, info, &tpi);

}



static __be64 key_to_tunnel_id(__be32 key)
@@ -268,6 +427,31 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) 
	return PACKET_REJECT;

}



static int gre_rcv(struct sk_buff *skb)

{

	struct tnl_ptk_info tpi;

	bool csum_err = false;



#ifdef CONFIG_NET_IPGRE_BROADCAST

	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {

		/* Looped back packet, drop it! */

		if (rt_is_output_route(skb_rtable(skb)))

			goto drop;

	}

#endif



	if (parse_gre_header(skb, &tpi, &csum_err) < 0)

		goto drop;



	if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)

		return 0;



	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

drop:

	kfree_skb(skb);

	return 0;

}



static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,

			 __be16 proto, __be32 key, __be32 seq)

{
@@ -684,10 +868,9 @@ static int ipgre_tunnel_init(struct net_device *dev) 
	return ip_tunnel_init(dev);

}



static struct gre_cisco_protocol ipgre_protocol = {

	.handler        = ipgre_rcv,

	.err_handler    = ipgre_err,

	.priority       = 0,

static const struct gre_protocol ipgre_protocol = {

	.handler     = gre_rcv,

	.err_handler = gre_err,

};



static int __net_init ipgre_init_net(struct net *net)
@@ -1080,7 +1263,7 @@ static int __init ipgre_init(void) 
	if (err < 0)

		goto pnet_tap_faied;



	err = gre_cisco_register(&ipgre_protocol);

	err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);

	if (err < 0) {

		pr_info("%s: can't add protocol\n", __func__);

		goto add_proto_failed;
@@ -1099,7 +1282,7 @@ static int __init ipgre_init(void) 
tap_ops_failed:

	rtnl_link_unregister(&ipgre_link_ops);

rtnl_link_failed:

	gre_cisco_unregister(&ipgre_protocol);

	gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);

add_proto_failed:

	unregister_pernet_device(&ipgre_tap_net_ops);

pnet_tap_faied:
@@ -1111,7 +1294,7 @@ static void __exit ipgre_fini(void) 
{

	rtnl_link_unregister(&ipgre_tap_ops);

	rtnl_link_unregister(&ipgre_link_ops);

	gre_cisco_unregister(&ipgre_protocol);

	gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);

	unregister_pernet_device(&ipgre_tap_net_ops);

	unregister_pernet_device(&ipgre_net_ops);

}