Commit 7ac64f45 authored by Christian Hopps's avatar Christian Hopps Committed by Steffen Klassert
Browse files

xfrm: add mode_cbs module functionality 



Add a set of callbacks xfrm_mode_cbs to xfrm_state. These callbacks
enable the addition of new xfrm modes, such as IP-TFS to be defined
in modules.

Signed-off-by: default avatarChristian Hopps <chopps@labn.net>
Tested-by: default avatarAntony Antony <antony.antony@secunet.com>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent f69eb4f6

include/net/xfrm.h

+43 −0
Original line number Diff line number Diff line
@@ -213,6 +213,7 @@ struct xfrm_state { 
		u16		family;

		xfrm_address_t	saddr;

		int		header_len;

		int		enc_hdr_len;

		int		trailer_len;

		u32		extra_flags;

		struct xfrm_mark	smark;
@@ -303,6 +304,9 @@ struct xfrm_state { 
	 * interpreted by xfrm_type methods. */

	void			*data;

	u8			dir;



	const struct xfrm_mode_cbs	*mode_cbs;

	void				*mode_data;

};



static inline struct net *xs_net(struct xfrm_state *x)
@@ -460,6 +464,45 @@ struct xfrm_type_offload { 
int xfrm_register_type_offload(const struct xfrm_type_offload *type, unsigned short family);

void xfrm_unregister_type_offload(const struct xfrm_type_offload *type, unsigned short family);



/**

 * struct xfrm_mode_cbs - XFRM mode callbacks

 * @owner: module owner or NULL

 * @init_state: Add/init mode specific state in `xfrm_state *x`

 * @clone_state: Copy mode specific values from `orig` to new state `x`

 * @destroy_state: Cleanup mode specific state from `xfrm_state *x`

 * @user_init: Process mode specific netlink attributes from user

 * @copy_to_user: Add netlink attributes to `attrs` based on state in `x`

 * @sa_len: Return space required to store mode specific netlink attributes

 * @get_inner_mtu: Return avail payload space after removing encap overhead

 * @input: Process received packet from SA using mode

 * @output: Output given packet using mode

 * @prepare_output: Add mode specific encapsulation to packet in skb. On return

 *	`transport_header` should point at ESP header, `network_header` should

 *	point at outer IP header and `mac_header` should opint at the

 *	protocol/nexthdr field of the outer IP.

 *

 * One should examine and understand the specific uses of these callbacks in

 * xfrm for further detail on how and when these functions are called. RTSL.

 */

struct xfrm_mode_cbs {

	struct module	*owner;

	int	(*init_state)(struct xfrm_state *x);

	int	(*clone_state)(struct xfrm_state *x, struct xfrm_state *orig);

	void	(*destroy_state)(struct xfrm_state *x);

	int	(*user_init)(struct net *net, struct xfrm_state *x,

			     struct nlattr **attrs,

			     struct netlink_ext_ack *extack);

	int	(*copy_to_user)(struct xfrm_state *x, struct sk_buff *skb);

	unsigned int (*sa_len)(const struct xfrm_state *x);

	u32	(*get_inner_mtu)(struct xfrm_state *x, int outer_mtu);

	int	(*input)(struct xfrm_state *x, struct sk_buff *skb);

	int	(*output)(struct net *net, struct sock *sk, struct sk_buff *skb);

	int	(*prepare_output)(struct xfrm_state *x, struct sk_buff *skb);

};



int xfrm_register_mode_cbs(u8 mode, const struct xfrm_mode_cbs *mode_cbs);

void xfrm_unregister_mode_cbs(u8 mode);



static inline int xfrm_af2proto(unsigned int family)

{

	switch(family) {

net/xfrm/xfrm_device.c

+2 −1
Original line number Diff line number Diff line
@@ -42,7 +42,8 @@ static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb, 
		skb->transport_header = skb->network_header + hsize;



	skb_reset_mac_len(skb);

	pskb_pull(skb, skb->mac_len + x->props.header_len);

	pskb_pull(skb,

		  skb->mac_len + x->props.header_len - x->props.enc_hdr_len);

}



static void __xfrm_mode_beet_prep(struct xfrm_state *x, struct sk_buff *skb,

net/xfrm/xfrm_input.c

+16 −2
Original line number Diff line number Diff line
@@ -446,6 +446,9 @@ static int xfrm_inner_mode_input(struct xfrm_state *x, 
		WARN_ON_ONCE(1);

		break;

	default:

		if (x->mode_cbs && x->mode_cbs->input)

			return x->mode_cbs->input(x, skb);



		WARN_ON_ONCE(1);

		break;

	}
@@ -453,6 +456,10 @@ static int xfrm_inner_mode_input(struct xfrm_state *x, 
	return -EOPNOTSUPP;

}



/* NOTE: encap_type - In addition to the normal (non-negative) values for

 * encap_type, a negative value of -1 or -2 can be used to resume/restart this

 * function after a previous invocation early terminated for async operation.

 */

int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)

{

	const struct xfrm_state_afinfo *afinfo;
@@ -489,6 +496,10 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) 


		family = x->props.family;



		/* An encap_type of -2 indicates reconstructed inner packet */

		if (encap_type == -2)

			goto resume_decapped;



		/* An encap_type of -1 indicates async resumption. */

		if (encap_type == -1) {

			async = 1;
@@ -679,11 +690,14 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) 


		XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;



		if (xfrm_inner_mode_input(x, skb)) {

		err = xfrm_inner_mode_input(x, skb);

		if (err == -EINPROGRESS)

			return 0;

		else if (err) {

			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);

			goto drop;

		}



resume_decapped:

		if (x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL) {

			decaps = 1;

			break;

net/xfrm/xfrm_output.c

+2 −0
Original line number Diff line number Diff line
@@ -472,6 +472,8 @@ static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb) 
		WARN_ON_ONCE(1);

		break;

	default:

		if (x->mode_cbs && x->mode_cbs->prepare_output)

			return x->mode_cbs->prepare_output(x, skb);

		WARN_ON_ONCE(1);

		break;

	}

net/xfrm/xfrm_policy.c

+11 −7
Original line number Diff line number Diff line
@@ -2748,6 +2748,9 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, 


		dst1->input = dst_discard;



		if (xfrm[i]->mode_cbs && xfrm[i]->mode_cbs->output) {

			dst1->output = xfrm[i]->mode_cbs->output;

		} else {

			rcu_read_lock();

			afinfo = xfrm_state_afinfo_get_rcu(inner_mode->family);

			if (likely(afinfo))
@@ -2755,6 +2758,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, 
			else

				dst1->output = dst_discard_out;

			rcu_read_unlock();

		}



		xdst_prev = xdst;