[IPSEC]: Add XFRMA_SA/XFRMA_POLICY for delete notification

This patch changes the format of the XFRM_MSG_DELSA and
XFRM_MSG_DELPOLICY notification so that the main message
sent is of the same format as that received by the kernel
if the original message was via netlink.  This also means
that we won't lose the byid information carried in km_event.

Since this user interface is introduced by Jamal's patch
we can still afford to change it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/xfrm.h

@@ -174,6 +174,8 @@ enum xfrm_attr_type_t {
 	XFRMA_ALG_COMP,		/* struct xfrm_algo */
 	XFRMA_ENCAP,		/* struct xfrm_algo + struct xfrm_encap_tmpl */
 	XFRMA_TMPL,		/* 1 or more struct xfrm_user_tmpl */
+	XFRMA_SA,
+	XFRMA_POLICY,
 	__XFRMA_MAX
 
 #define XFRMA_MAX (__XFRMA_MAX - 1)

net/xfrm/xfrm_user.c

@@ -1168,7 +1168,7 @@ nlmsg_failure:
 
 static int inline xfrm_sa_len(struct xfrm_state *x)
 {
-	int l = NLMSG_LENGTH(sizeof(struct xfrm_usersa_info));
+	int l = 0;
 	if (x->aalg)
 		l += RTA_SPACE(sizeof(*x->aalg) + (x->aalg->alg_key_len+7)/8);
 	if (x->ealg)
@@ -1184,20 +1184,39 @@ static int inline xfrm_sa_len(struct xfrm_state *x)
 static int xfrm_notify_sa(struct xfrm_state *x, struct km_event *c)
 {
 	struct xfrm_usersa_info *p;
+	struct xfrm_usersa_id *id;
 	struct nlmsghdr *nlh;
 	struct sk_buff *skb;
 	unsigned char *b;
 	int len = xfrm_sa_len(x);
+	int headlen;
+
+	headlen = sizeof(*p);
+	if (c->event == XFRM_MSG_DELSA) {
+		len += RTA_SPACE(headlen);
+		headlen = sizeof(*id);
+	}
+	len += NLMSG_SPACE(headlen);
 
 	skb = alloc_skb(len, GFP_ATOMIC);
 	if (skb == NULL)
 		return -ENOMEM;
 	b = skb->tail;
 
-	nlh = NLMSG_PUT(skb, c->pid, c->seq, c->event, sizeof(*p));
+	nlh = NLMSG_PUT(skb, c->pid, c->seq, c->event, headlen);
 	nlh->nlmsg_flags = 0;
 
 	p = NLMSG_DATA(nlh);
+	if (c->event == XFRM_MSG_DELSA) {
+		id = NLMSG_DATA(nlh);
+		memcpy(&id->daddr, &x->id.daddr, sizeof(id->daddr));
+		id->spi = x->id.spi;
+		id->family = x->props.family;
+		id->proto = x->id.proto;
+
+		p = RTA_DATA(__RTA_PUT(skb, XFRMA_SA, sizeof(*p)));
+	}
+
 	copy_to_user_state(x, p);
 
 	if (x->aalg)
@@ -1398,20 +1417,39 @@ static int xfrm_exp_policy_notify(struct xfrm_policy *xp, int dir, struct km_eve
 static int xfrm_notify_policy(struct xfrm_policy *xp, int dir, struct km_event *c)
 {
 	struct xfrm_userpolicy_info *p;
+	struct xfrm_userpolicy_id *id;
 	struct nlmsghdr *nlh;
 	struct sk_buff *skb;
 	unsigned char *b;
 	int len = RTA_SPACE(sizeof(struct xfrm_user_tmpl) * xp->xfrm_nr);
-	len += NLMSG_SPACE(sizeof(struct xfrm_userpolicy_info));
+	int headlen;
+
+	headlen = sizeof(*p);
+	if (c->event == XFRM_MSG_DELPOLICY) {
+		len += RTA_SPACE(headlen);
+		headlen = sizeof(*id);
+	}
+	len += NLMSG_SPACE(headlen);
 
 	skb = alloc_skb(len, GFP_ATOMIC);
 	if (skb == NULL)
 		return -ENOMEM;
 	b = skb->tail;
 
-	nlh = NLMSG_PUT(skb, c->pid, c->seq, c->event, sizeof(*p));
+	nlh = NLMSG_PUT(skb, c->pid, c->seq, c->event, headlen);
 
 	p = NLMSG_DATA(nlh);
+	if (c->event == XFRM_MSG_DELPOLICY) {
+		id = NLMSG_DATA(nlh);
+		memset(id, 0, sizeof(*id));
+		id->dir = dir;
+		if (c->data.byid)
+			id->index = xp->index;
+		else
+			memcpy(&id->sel, &xp->selector, sizeof(id->sel));
+
+		p = RTA_DATA(__RTA_PUT(skb, XFRMA_POLICY, sizeof(*p)));
+	}
 
 	nlh->nlmsg_flags = 0;
 
@@ -1424,6 +1462,7 @@ static int xfrm_notify_policy(struct xfrm_policy *xp, int dir, struct km_event *
 	return netlink_broadcast(xfrm_nl, skb, 0, XFRMGRP_POLICY, GFP_ATOMIC);
 
 nlmsg_failure:
+rtattr_failure:
 	kfree_skb(skb);
 	return -1;
 }