/* xfrm_user.c: User interface to configure xfrm engine.
 *
 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/init.h>
#include <net/sock.h>
#include <net/xfrm.h>

static struct sock *xfrm_nl;

static int verify_one_alg(struct rtattr **xfrma, enum xfrm_attr_type_t type)
{
	struct rtattr *rt = xfrma[type - 1];
	struct xfrm_algo *algp;

	if (!rt)
		return 0;

	if ((rt->rta_len - sizeof(*rt)) < sizeof(*algp))
		return -EINVAL;

	algp = RTA_DATA(rt);
	switch (type) {
	case XFRMA_ALG_AUTH:
	case XFRMA_ALG_CRYPT:
		if (!algp->alg_key_len)
			return -EINVAL;
		break;

	case XFRMA_ALG_COMP:
		/* Zero length keys are legal.  */
		break;

	default:
		return -EINVAL;
	};

	algp->alg_name[CRYPTO_MAX_ALG_NAME - 1] = '\0';
	return 0;
}

static int verify_newsa_info(struct xfrm_usersa_info *p,
			     struct rtattr **xfrma)
{
	int err;

	err = -EINVAL;
	switch (p->family) {
	case AF_INET:
		break;

	case AF_INET6: /* XXX */
		err = -EAFNOSUPPORT;

		/* fallthru */
	default:
		goto out;
	};

	err = -EINVAL;
	switch (p->id.proto) {
	case IPPROTO_AH:
		if (!xfrma[XFRMA_ALG_AUTH-1]	||
		    xfrma[XFRMA_ALG_CRYPT-1]	||
		    xfrma[XFRMA_ALG_COMP-1])
			goto out;
		break;

	case IPPROTO_ESP:
		if ((!xfrma[XFRMA_ALG_AUTH-1] &&
		     !xfrma[XFRMA_ALG_CRYPT-1])	||
		    xfrma[XFRMA_ALG_COMP-1])
			goto out;
		break;

	case IPPROTO_COMP:
		if (!xfrma[XFRMA_ALG_COMP-1]	||
		    xfrma[XFRMA_ALG_AUTH-1]	||
		    xfrma[XFRMA_ALG_CRYPT-1])
			goto out;
		break;

	default:
		goto out;
	};

	if ((err = verify_one_alg(xfrma, XFRMA_ALG_AUTH)))
		goto out;
	if ((err = verify_one_alg(xfrma, XFRMA_ALG_CRYPT)))
		goto out;
	if ((err = verify_one_alg(xfrma, XFRMA_ALG_COMP)))
		goto out;

	err = -EINVAL;
	switch (p->mode) {
	case 0:
	case 1:
		break;

	default:
		goto out;
	};

	err = 0;

out:
	return err;
}

static int attach_one_algo(struct xfrm_algo **algpp, struct rtattr *u_arg)
{
	struct rtattr *rta = u_arg;
	struct xfrm_algo *p, *ualg;

	if (!rta)
		return 0;

	ualg = RTA_DATA(rta);
	p = kmalloc(sizeof(*ualg) + ualg->alg_key_len, GFP_KERNEL);
	if (!p)
		return -ENOMEM;

	memcpy(p, ualg, sizeof(*ualg) + ualg->alg_key_len);
	*algpp = p;
	return 0;
}

static void copy_from_user_state(struct xfrm_state *x, struct xfrm_usersa_info *p)
{
	memcpy(&x->id, &p->id, sizeof(x->id));
	memcpy(&x->sel, &p->sel, sizeof(x->sel));
	memcpy(&x->lft, &p->lft, sizeof(x->lft));
	x->props.mode = p->mode;
	x->props.replay_window = p->replay_window;
	x->props.reqid = p->reqid;
	x->props.family = p->family;
	x->props.saddr = x->sel.saddr;
}

static struct xfrm_state *xfrm_state_construct(struct xfrm_usersa_info *p,
					       struct rtattr **xfrma,
					       int *errp)
{
	struct xfrm_state *x = xfrm_state_alloc();
	int err = -ENOMEM;

	if (!x)
		goto error_no_put;

	copy_from_user_state(x, p);

	if ((err = attach_one_algo(&x->aalg, xfrma[XFRMA_ALG_AUTH-1])))
		goto error;
	if ((err = attach_one_algo(&x->ealg, xfrma[XFRMA_ALG_CRYPT-1])))
		goto error;
	if ((err = attach_one_algo(&x->calg, xfrma[XFRMA_ALG_COMP-1])))
		goto error;

	err = -ENOENT;
	x->type = xfrm_get_type(x->id.proto);
	if (x->type == NULL)
		goto error;

	err = x->type->init_state(x, NULL);
	if (err)
		goto error;

	x->curlft.add_time = (unsigned long) xtime.tv_sec;
	x->km.state = XFRM_STATE_VALID;
	x->km.seq = p->seq;

	return x;

error:
	xfrm_state_put(x);
error_no_put:
	*errp = err;
	return NULL;
}

static int xfrm_add_sa(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_usersa_info *p = NLMSG_DATA(nlh);
	struct xfrm_state *x, *x1;
	int err;

	err = verify_newsa_info(p, (struct rtattr **) xfrma);
	if (err)
		return err;

	x = xfrm_state_construct(p, (struct rtattr **) xfrma, &err);
	if (!x)
		return err;

	x1 = xfrm_state_lookup(x->props.saddr.xfrm4_addr,
			       x->id.spi, x->id.proto);
	if (x1) {
		xfrm_state_put(x);
		xfrm_state_put(x1);
		return -EEXIST;
	}

	xfrm_state_insert(x);

	return 0;
}

static int xfrm_del_sa(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_state *x;
	struct xfrm_usersa_id *p = NLMSG_DATA(nlh);

	x = xfrm_state_lookup(p->saddr.xfrm4_addr, p->spi, p->proto);
	if (x == NULL)
		return -ESRCH;

	xfrm_state_delete(x);
	xfrm_state_put(x);

	return 0;
}

static void copy_to_user_state(struct xfrm_state *x, struct xfrm_usersa_info *p)
{
	memcpy(&p->id, &x->id, sizeof(p->id));
	memcpy(&p->sel, &x->sel, sizeof(p->sel));
	memcpy(&p->lft, &x->lft, sizeof(p->lft));
	memcpy(&p->curlft, &x->curlft, sizeof(p->curlft));
	memcpy(&p->stats, &x->stats, sizeof(p->stats));
	p->mode = x->props.mode;
	p->replay_window = x->props.replay_window;
	p->reqid = x->props.reqid;
	p->family = x->props.family;
	p->seq = x->km.seq;
}

struct xfrm_dump_info {
	struct sk_buff *in_skb;
	struct sk_buff *out_skb;
	u32 nlmsg_seq;
	int start_idx;
	int this_idx;
};

static int dump_one_state(struct xfrm_state *x, int count, void *ptr)
{
	struct xfrm_dump_info *sp = ptr;
	struct sk_buff *in_skb = sp->in_skb;
	struct sk_buff *skb = sp->out_skb;
	struct xfrm_usersa_info *p;
	struct nlmsghdr *nlh;
	unsigned char *b = skb->tail;

	if (sp->this_idx < sp->start_idx)
		goto out;

	nlh = NLMSG_PUT(skb, NETLINK_CB(in_skb).pid,
			sp->nlmsg_seq,
			XFRM_MSG_NEWSA, sizeof(*p));
	nlh->nlmsg_flags = 0;

	p = NLMSG_DATA(nlh);
	copy_to_user_state(x, p);

	if (x->aalg)
		RTA_PUT(skb, XFRMA_ALG_AUTH, sizeof(*(x->aalg)), x->aalg);
	if (x->ealg)
		RTA_PUT(skb, XFRMA_ALG_CRYPT, sizeof(*(x->ealg)), x->ealg);
	if (x->calg)
		RTA_PUT(skb, XFRMA_ALG_COMP, sizeof(*(x->calg)), x->calg);

	nlh->nlmsg_len = skb->tail - b;
out:
	sp->this_idx++;
	return 0;

nlmsg_failure:
rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct xfrm_dump_info info;

	info.in_skb = cb->skb;
	info.out_skb = skb;
	info.nlmsg_seq = cb->nlh->nlmsg_seq;
	info.this_idx = 0;
	info.start_idx = cb->args[0];
	(void) xfrm_state_walk(IPSEC_PROTO_ANY, dump_one_state, &info);
	cb->args[0] = info.this_idx;

	return skb->len;
}

static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb,
					  struct xfrm_state *x, u32 seq)
{
	struct xfrm_dump_info info;
	struct sk_buff *skb;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
	if (!skb)
		return ERR_PTR(-ENOMEM);

	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
	info.in_skb = in_skb;
	info.out_skb = skb;
	info.nlmsg_seq = seq;
	info.this_idx = info.start_idx = 0;

	if (dump_one_state(x, 0, &info)) {
		kfree_skb(skb);
		return NULL;
	}

	return skb;
}

static int xfrm_get_sa(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_usersa_id *p = NLMSG_DATA(nlh);
	struct xfrm_state *x;
	struct sk_buff *resp_skb;
	int err;

	x = xfrm_state_lookup(p->saddr.xfrm4_addr, p->spi, p->proto);
	err = -ESRCH;
	if (x == NULL)
		goto out_noput;

	resp_skb = xfrm_state_netlink(skb, x, nlh->nlmsg_seq);
	if (IS_ERR(resp_skb)) {
		err = PTR_ERR(resp_skb);
	} else {
		err = netlink_unicast(xfrm_nl, resp_skb,
				      NETLINK_CB(skb).pid, MSG_DONTWAIT);
	}
	xfrm_state_put(x);
out_noput:
	return err;
}

static int verify_userspi_info(struct xfrm_userspi_info *p)
{
	switch (p->info.id.proto) {
	case IPPROTO_AH:
	case IPPROTO_ESP:
		break;

	case IPPROTO_COMP:
		/* IPCOMP spi is 16-bits. */
		if (p->min >= 0x10000 ||
		    p->max >= 0x10000)
			return -EINVAL;

	default:
		return -EINVAL;
	};

	if (p->min > p->max)
		return -EINVAL;

	return 0;
}

static int xfrm_alloc_userspi(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_state *x;
	struct xfrm_userspi_info *p;
	struct sk_buff *resp_skb;
	int err;

	p = NLMSG_DATA(nlh);
	err = verify_userspi_info(p);
	if (err)
		goto out_noput;
	x = xfrm_find_acq(p->info.mode, p->info.reqid, p->info.id.proto,
			  p->info.sel.daddr.xfrm4_addr,
			  p->info.sel.saddr.xfrm4_addr, 1);
	err = -ENOENT;
	if (x == NULL)
		goto out_noput;

	resp_skb = ERR_PTR(-ENOENT);

	spin_lock_bh(&x->lock);
	if (x->km.state != XFRM_STATE_DEAD) {
		xfrm_alloc_spi(x, p->min, p->max);
		if (x->id.spi)
			resp_skb = xfrm_state_netlink(skb, x, nlh->nlmsg_seq);
	}
	spin_unlock_bh(&x->lock);

	if (IS_ERR(resp_skb)) {
		err = PTR_ERR(resp_skb);
		goto out;
	}

	err = netlink_unicast(xfrm_nl, resp_skb,
			      NETLINK_CB(skb).pid, MSG_DONTWAIT);

out:
	xfrm_state_put(x);
out_noput:
	return err;
}

static int verify_policy_dir(__u8 dir)
{
	switch (dir) {
	case XFRM_POLICY_IN:
	case XFRM_POLICY_OUT:
	case XFRM_POLICY_FWD:
		break;

	default:
		return -EINVAL;
	};

	return 0;
}

static int verify_newpolicy_info(struct xfrm_userpolicy_info *p)
{
	switch (p->share) {
	case XFRM_SHARE_ANY:
	case XFRM_SHARE_SESSION:
	case XFRM_SHARE_USER:
	case XFRM_SHARE_UNIQUE:
		break;

	default:
		return -EINVAL;
	};

	switch (p->action) {
	case XFRM_POLICY_ALLOW:
	case XFRM_POLICY_BLOCK:
		break;

	default:
		return -EINVAL;
	};

	return verify_policy_dir(p->dir);
}

static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut,
			   int nr)
{
	int i;

	xp->xfrm_nr = nr;
	for (i = 0; i < nr; i++, ut++) {
		struct xfrm_tmpl *t = &xp->xfrm_vec[i];

		memcpy(&t->id, &ut->id, sizeof(struct xfrm_id));
		memcpy(&t->saddr, &ut->saddr,
		       sizeof(xfrm_address_t));
		t->reqid = ut->reqid;
		t->mode = ut->mode;
		t->share = ut->share;
		t->optional = ut->optional;
		t->aalgos = ut->aalgos;
		t->ealgos = ut->ealgos;
		t->calgos = ut->calgos;
	}
}

static int copy_user_tmpl(struct xfrm_policy *pol, struct rtattr **xfrma)
{
	struct rtattr *rt = xfrma[XFRMA_TMPL-1];
	struct xfrm_user_tmpl *utmpl;
	int nr;

	if (!rt) {
		pol->xfrm_nr = 0;
	} else {
		nr = (rt->rta_len - sizeof(*rt)) / sizeof(*utmpl);

		if (nr > XFRM_MAX_DEPTH)
			return -EINVAL;

		copy_templates(pol, RTA_DATA(rt), nr);
	}
	return 0;
}

static void copy_from_user_policy(struct xfrm_policy *xp, struct xfrm_userpolicy_info *p)
{
	xp->priority = p->priority;
	xp->index = p->index;
	memcpy(&xp->selector, &p->sel, sizeof(xp->selector));
	memcpy(&xp->lft, &p->lft, sizeof(xp->lft));
	xp->action = p->action;
	xp->flags = p->flags;
	xp->family = p->family;
	/* XXX xp->share = p->share; */
}

static void copy_to_user_policy(struct xfrm_policy *xp, struct xfrm_userpolicy_info *p, int dir)
{
	memcpy(&p->sel, &xp->selector, sizeof(p->sel));
	memcpy(&p->lft, &xp->lft, sizeof(p->lft));
	memcpy(&p->curlft, &xp->curlft, sizeof(p->curlft));
	p->priority = xp->priority;
	p->index = xp->index;
	p->family = xp->family;
	p->dir = dir;
	p->action = xp->action;
	p->flags = xp->flags;
	p->share = XFRM_SHARE_ANY; /* XXX xp->share */
}

static struct xfrm_policy *xfrm_policy_construct(struct xfrm_userpolicy_info *p, struct rtattr **xfrma, int *errp)
{
	struct xfrm_policy *xp = xfrm_policy_alloc(GFP_KERNEL);
	int err;

	if (!xp) {
		*errp = -ENOMEM;
		return NULL;
	}

	copy_from_user_policy(xp, p);
	err = copy_user_tmpl(xp, xfrma);
	if (err) {
		*errp = err;
		kfree(xp);
		xp = NULL;
	}

	return xp;
}

static int xfrm_add_policy(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_userpolicy_info *p = NLMSG_DATA(nlh);
	struct xfrm_policy *xp;
	int err;

	err = verify_newpolicy_info(p);
	if (err)
		return err;

	xp = xfrm_policy_construct(p, (struct rtattr **) xfrma, &err);
	if (!xp)
		return err;

	err = xfrm_policy_insert(p->dir, xp, 1);
	if (err) {
		kfree(xp);
		return err;
	}

	xfrm_pol_put(xp);

	return 0;
}

static int xfrm_del_policy(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_policy *xp;
	struct xfrm_userpolicy_id *p;
	int err;

	p = NLMSG_DATA(nlh);

	err = verify_policy_dir(p->dir);
	if (err)
		return err;

	xp = xfrm_policy_delete(p->dir, &p->sel);
	if (xp == NULL)
		return -ENOENT;
	xfrm_policy_kill(xp);
	xfrm_pol_put(xp);
	return 0;
}

static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr)
{
	struct xfrm_dump_info *sp = ptr;
	struct xfrm_userpolicy_info *p;
	struct sk_buff *in_skb = sp->in_skb;
	struct sk_buff *skb = sp->out_skb;
	struct nlmsghdr *nlh;
	unsigned char *b = skb->tail;

	if (sp->this_idx < sp->start_idx)
		goto out;

	nlh = NLMSG_PUT(skb, NETLINK_CB(in_skb).pid,
			sp->nlmsg_seq,
			XFRM_MSG_NEWPOLICY, sizeof(*p));
	p = NLMSG_DATA(nlh);
	nlh->nlmsg_flags = 0;

	copy_to_user_policy(xp, p, dir);

	if (xp->xfrm_nr) {
		struct xfrm_user_tmpl vec[XFRM_MAX_DEPTH];
		int i;

		for (i = 0; i < xp->xfrm_nr; i++) {
			struct xfrm_user_tmpl *up = &vec[i];
			struct xfrm_tmpl *kp = &xp->xfrm_vec[i];

			memcpy(&up->id, &kp->id, sizeof(up->id));
			memcpy(&up->saddr, &kp->saddr, sizeof(up->saddr));
			up->reqid = kp->reqid;
			up->mode = kp->mode;
			up->share = kp->share;
			up->optional = kp->optional;
			up->aalgos = kp->aalgos;
			up->ealgos = kp->ealgos;
			up->calgos = kp->calgos;
		}
		RTA_PUT(skb, XFRMA_TMPL,
			(sizeof(struct xfrm_user_tmpl) * xp->xfrm_nr),
			vec);
	}

	nlh->nlmsg_len = skb->tail - b;
out:
	sp->this_idx++;
	return 0;

nlmsg_failure:
rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int xfrm_dump_policy(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct xfrm_dump_info info;

	info.in_skb = cb->skb;
	info.out_skb = skb;
	info.nlmsg_seq = cb->nlh->nlmsg_seq;
	info.start_idx = cb->args[0];
	(void) xfrm_policy_walk(dump_one_policy, &info);
	cb->args[0] = info.this_idx;

	return skb->len;
}

static struct sk_buff *xfrm_policy_netlink(struct sk_buff *in_skb,
					  struct xfrm_policy *xp,
					  int dir, u32 seq)
{
	struct xfrm_dump_info info;
	struct sk_buff *skb;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return ERR_PTR(-ENOMEM);

	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
	info.in_skb = in_skb;
	info.out_skb = skb;
	info.nlmsg_seq = seq;
	info.this_idx = info.start_idx = 0;

	if (dump_one_policy(xp, dir, 0, &info) < 0) {
		kfree_skb(skb);
		return NULL;
	}

	return skb;
}

static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh, void **xfrma)
{
	struct xfrm_policy *xp;
	struct xfrm_userpolicy_id *p;
	struct sk_buff *resp_skb;
	int err;

	p = NLMSG_DATA(nlh);
	xp = xfrm_policy_byid(p->dir, p->index, 0);
	if (xp == NULL)
		return -ENOENT;

	resp_skb = xfrm_policy_netlink(skb, xp, p->dir, nlh->nlmsg_seq);
	if (IS_ERR(resp_skb)) {
		err = PTR_ERR(resp_skb);
	} else {
		err = netlink_unicast(xfrm_nl, resp_skb,
				      NETLINK_CB(skb).pid, MSG_DONTWAIT);
	}

	xfrm_pol_put(xp);

	return err;
}

static const int xfrm_msg_min[(XFRM_MSG_MAX + 1 - XFRM_MSG_BASE)] = {
	NLMSG_LENGTH(sizeof(struct xfrm_usersa_info)),	/* NEW SA */
	NLMSG_LENGTH(sizeof(struct xfrm_usersa_id)),	/* DEL SA */
	NLMSG_LENGTH(sizeof(struct xfrm_usersa_id)),	/* GET SA */
	NLMSG_LENGTH(sizeof(struct xfrm_userpolicy_info)),/* NEW POLICY */
	NLMSG_LENGTH(sizeof(struct xfrm_userpolicy_id)),  /* DEL POLICY */
	NLMSG_LENGTH(sizeof(struct xfrm_userpolicy_id)),  /* GET POLICY */
	NLMSG_LENGTH(sizeof(struct xfrm_userspi_info)),	/* ALLOC SPI */
	NLMSG_LENGTH(sizeof(struct xfrm_user_acquire)),	/* ACQUIRE */
	NLMSG_LENGTH(sizeof(struct xfrm_user_expire)),	/* EXPIRE */
};

static struct xfrm_link {
	int (*doit)(struct sk_buff *, struct nlmsghdr *, void **);
	int (*dump)(struct sk_buff *, struct netlink_callback *);
} xfrm_dispatch[] = {
	{	.doit	=	xfrm_add_sa, 		},
	{	.doit	=	xfrm_del_sa, 		},
	{
		.doit	=	xfrm_get_sa,
		.dump	=	xfrm_dump_sa,
	},
	{	.doit	=	xfrm_add_policy 	},
	{	.doit	=	xfrm_del_policy 	},
	{
		.doit	=	xfrm_get_policy,
		.dump	=	xfrm_dump_policy,
	},
	{	.doit	=	xfrm_alloc_userspi	},
};

static int xfrm_done(struct netlink_callback *cb)
{
	return 0;
}

static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
{
	struct rtattr *xfrma[XFRMA_MAX];
	struct xfrm_link *link;
	int type, min_len, kind;

	if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
		return 0;

	type = nlh->nlmsg_type;

	/* A control message: ignore them */
	if (type < XFRM_MSG_BASE)
		return 0;

	/* Unknown message: reply with EINVAL */
	if (type > XFRM_MSG_MAX)
		goto err_einval;

	type -= XFRM_MSG_BASE;
	kind = (type & 3);
	link = &xfrm_dispatch[type];

	/* All operations require privileges, even GET */
	if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
		*errp = -EPERM;
		return -1;
	}

	if (kind == 2 && (nlh->nlmsg_flags & NLM_F_DUMP)) {
		u32 rlen;

		if (link->dump == NULL)
			goto err_einval;

		if ((*errp = netlink_dump_start(xfrm_nl, skb, nlh,
						link->dump,
						xfrm_done)) != 0) {
			return -1;
		}
		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
		if (rlen > skb->len)
			rlen = skb->len;
		skb_pull(skb, rlen);
		return -1;
	}

	memset(xfrma, 0, sizeof(xfrma));

	if (nlh->nlmsg_len < (min_len = xfrm_msg_min[type]))
		goto err_einval;

	if (nlh->nlmsg_len > min_len) {
		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
		struct rtattr *attr = (void *) nlh + NLMSG_ALIGN(min_len);

		while (RTA_OK(attr, attrlen)) {
			unsigned short flavor = attr->rta_type;
			if (flavor) {
				if (flavor > XFRMA_MAX)
					goto err_einval;
				xfrma[flavor - 1] = attr;
			}
			attr = RTA_NEXT(attr, attrlen);
		}
	}

	if (link->doit == NULL)
		goto err_einval;
	*errp = link->doit(skb, nlh, (void **) &xfrma);

	return *errp;

err_einval:
	*errp = -EINVAL;
	return -1;
}

static int xfrm_user_rcv_skb(struct sk_buff *skb)
{
	int err;
	struct nlmsghdr *nlh;

	while (skb->len >= NLMSG_SPACE(0)) {
		u32 rlen;

		nlh = (struct nlmsghdr *) skb->data;
		if (nlh->nlmsg_len < sizeof(*nlh) ||
		    skb->len < nlh->nlmsg_len)
			return 0;
		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
		if (rlen > skb->len)
			rlen = skb->len;
		if (xfrm_user_rcv_msg(skb, nlh, &err)) {
			if (err == 0)
				return -1;
			netlink_ack(skb, nlh, err);
		} else if (nlh->nlmsg_flags & NLM_F_ACK)
			netlink_ack(skb, nlh, 0);
		skb_pull(skb, rlen);
	}

	return 0;
}

static void xfrm_netlink_rcv(struct sock *sk, int len)
{
	do {
		struct sk_buff *skb;

		down(&xfrm_cfg_sem);

		while ((skb = skb_dequeue(&sk->receive_queue)) != NULL) {
			if (xfrm_user_rcv_skb(skb)) {
				if (skb->len)
					skb_queue_head(&sk->receive_queue, skb);
				else
					kfree_skb(skb);
				break;
			}
			kfree_skb(skb);
		}

		up(&xfrm_cfg_sem);

	} while (xfrm_nl && xfrm_nl->receive_queue.qlen);
}

static int build_expire(struct sk_buff *skb, struct xfrm_state *x, int hard)
{
	struct xfrm_user_expire *ue;
	struct nlmsghdr *nlh;
	unsigned char *b = skb->tail;

	nlh = NLMSG_PUT(skb, 0, 0, XFRM_MSG_EXPIRE,
			sizeof(*ue));
	ue = NLMSG_DATA(nlh);
	nlh->nlmsg_flags = 0;

	copy_to_user_state(x, &ue->state);
	ue->hard = (hard != 0) ? 1 : 0;

	nlh->nlmsg_len = skb->tail - b;
	return skb->len;

nlmsg_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int xfrm_send_notify(struct xfrm_state *x, int hard)
{
	struct sk_buff *skb;

	skb = alloc_skb(sizeof(struct xfrm_user_expire) + 16, GFP_ATOMIC);
	if (skb == NULL)
		return -ENOMEM;

	if (build_expire(skb, x, hard) < 0)
		BUG();

	NETLINK_CB(skb).dst_groups = XFRMGRP_EXPIRE;

	return netlink_broadcast(xfrm_nl, skb, 0, XFRMGRP_EXPIRE, GFP_ATOMIC);
}

/* XXX Make this xfrm_state.c:xfrm_get_acqseq() */
static u32 get_acqseq(void)
{
	u32 res;
	static u32 acqseq;
	static spinlock_t acqseq_lock = SPIN_LOCK_UNLOCKED;

	spin_lock_bh(&acqseq_lock);
	res = (++acqseq ? : ++acqseq);
	spin_unlock_bh(&acqseq_lock);
	return res;
}

static int build_acquire(struct sk_buff *skb, struct xfrm_state *x,
			 struct xfrm_tmpl *xt, struct xfrm_policy *xp,
			 int dir)
{
	struct xfrm_user_acquire *ua;
	struct nlmsghdr *nlh;
	unsigned char *b = skb->tail;
	__u32 seq = get_acqseq();

	nlh = NLMSG_PUT(skb, 0, 0, XFRM_MSG_ACQUIRE,
			sizeof(*ua));
	ua = NLMSG_DATA(nlh);
	nlh->nlmsg_flags = 0;

	memcpy(&ua->id, &x->id, sizeof(ua->id));
	memcpy(&ua->saddr, &x->props.saddr, sizeof(ua->saddr));
	copy_to_user_policy(xp, &ua->policy, dir);
	ua->aalgos = xt->aalgos;
	ua->ealgos = xt->ealgos;
	ua->calgos = xt->calgos;
	ua->seq = x->km.seq = seq;

	nlh->nlmsg_len = skb->tail - b;
	return skb->len;

nlmsg_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int xfrm_send_acquire(struct xfrm_state *x, struct xfrm_tmpl *xt,
			     struct xfrm_policy *xp, int dir)
{
	struct sk_buff *skb;

	skb = alloc_skb(sizeof(struct xfrm_user_acquire) + 16, GFP_ATOMIC);
	if (skb == NULL)
		return -ENOMEM;

	if (build_acquire(skb, x, xt, xp, dir) < 0)
		BUG();

	NETLINK_CB(skb).dst_groups = XFRMGRP_ACQUIRE;

	return netlink_broadcast(xfrm_nl, skb, 0, XFRMGRP_ACQUIRE, GFP_ATOMIC);
}

/* User gives us xfrm_user_policy_info followed by an array of 0
 * or more templates.
 */
struct xfrm_policy *xfrm_compile_policy(int opt, u8 *data, int len, int *dir)
{
	struct xfrm_userpolicy_info *p = (struct xfrm_userpolicy_info *)data;
	struct xfrm_user_tmpl *ut = (struct xfrm_user_tmpl *) (p + 1);
	struct xfrm_policy *xp;
	int nr;

	if (opt != IP_XFRM_POLICY) {
		*dir = -EOPNOTSUPP;
		return NULL;
	}
	*dir = -EINVAL;

	if (len < sizeof(*p) ||
	    verify_newpolicy_info(p))
		return NULL;

	nr = ((len - sizeof(*p)) / sizeof(*ut));
	if (nr > XFRM_MAX_DEPTH)
		return NULL;

	xp = xfrm_policy_alloc(GFP_KERNEL);
	if (xp == NULL) {
		*dir = -ENOBUFS;
		return NULL;
	}

	copy_from_user_policy(xp, p);
	copy_templates(xp, ut, nr);

	*dir = p->dir;

	return xp;
}

static struct xfrm_mgr netlink_mgr = {
	.id		= "netlink",
	.notify		= xfrm_send_notify,
	.acquire	= xfrm_send_acquire,
	.compile_policy	= xfrm_compile_policy,
};

static int __init xfrm_user_init(void)
{
	printk(KERN_INFO "Initializing IPsec netlink socket\n");

	xfrm_nl = netlink_kernel_create(NETLINK_XFRM, xfrm_netlink_rcv);
	if (xfrm_nl == NULL)
		panic("xfrm_user_init: cannot initialize xfrm_nl\n");


	xfrm_register_km(&netlink_mgr);

	return 0;
}

static void __exit xfrm_user_exit(void)
{
	xfrm_unregister_km(&netlink_mgr);
	sock_release(xfrm_nl->socket);
}

module_init(xfrm_user_init);
module_exit(xfrm_user_exit);
