xfrm: Extend the output_mark to support input direction and masking.

We already support setting an output mark at the xfrm_state,
unfortunately this does not support the input direction and
masking the marks that will be applied to the skb. This change
adds support applying a masked value in both directions.

The existing XFRMA_OUTPUT_MARK number is reused for this purpose
and as it is now bi-directional, it is renamed to XFRMA_SET_MARK.

An additional XFRMA_SET_MARK_MASK attribute is added for setting the
mask. If the attribute mask not provided, it is set to 0xffffffff,
keeping the XFRMA_OUTPUT_MARK existing 'full mask' semantics.

Co-developed-by: Tobias Brunner <tobias@strongswan.org>
Co-developed-by: Eyal Birger <eyal.birger@gmail.com>
Co-developed-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>

include/net/xfrm.h

@@ -166,7 +166,7 @@ struct xfrm_state {
 		int		header_len;
 		int		trailer_len;
 		u32		extra_flags;
-		u32		output_mark;
+		struct xfrm_mark	smark;
 	} props;
 
 	struct xfrm_lifetime_cfg lft;
@@ -2012,6 +2012,13 @@ static inline int xfrm_mark_put(struct sk_buff *skb, const struct xfrm_mark *m)
 	return ret;
 }
 
+static inline __u32 xfrm_smark_get(__u32 mark, struct xfrm_state *x)
+{
+	struct xfrm_mark *m = &x->props.smark;
+
+	return (m->v & m->m) | (mark & ~m->m);
+}
+
 static inline int xfrm_tunnel_check(struct sk_buff *skb, struct xfrm_state *x,
 				    unsigned int family)
 {

include/uapi/linux/xfrm.h

@@ -305,9 +305,11 @@ enum xfrm_attr_type_t {
 	XFRMA_ADDRESS_FILTER,	/* struct xfrm_address_filter */
 	XFRMA_PAD,
 	XFRMA_OFFLOAD_DEV,	/* struct xfrm_state_offload */
-	XFRMA_OUTPUT_MARK,	/* __u32 */
+	XFRMA_SET_MARK,		/* __u32 */
+	XFRMA_SET_MARK_MASK,	/* __u32 */
 	__XFRMA_MAX
 
+#define XFRMA_OUTPUT_MARK XFRMA_SET_MARK	/* Compatibility */
 #define XFRMA_MAX (__XFRMA_MAX - 1)
 };
 

net/xfrm/xfrm_device.c

@@ -162,7 +162,8 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 		}
 
 		dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
-					x->props.family, x->props.output_mark);
+					x->props.family,
+					xfrm_smark_get(0, x));
 		if (IS_ERR(dst))
 			return 0;
 

net/xfrm/xfrm_input.c

@@ -339,6 +339,8 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 			goto drop;
 		}
 
+		skb->mark = xfrm_smark_get(skb->mark, x);
+
 		skb->sp->xvec[skb->sp->len++] = x;
 
 lock:

net/xfrm/xfrm_output.c

@@ -66,8 +66,7 @@ static int xfrm_output_one(struct sk_buff *skb, int err)
 			goto error_nolock;
 		}
 
-		if (x->props.output_mark)
-			skb->mark = x->props.output_mark;
+		skb->mark = xfrm_smark_get(skb->mark, x);
 
 		err = x->outer_mode->output(x, skb);
 		if (err) {

net/xfrm/xfrm_policy.c

@@ -1607,10 +1607,11 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
 		dst_copy_metrics(dst1, dst);
 
 		if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
+			__u32 mark = xfrm_smark_get(fl->flowi_mark, xfrm[i]);
+
 			family = xfrm[i]->props.family;
 			dst = xfrm_dst_lookup(xfrm[i], tos, fl->flowi_oif,
-					      &saddr, &daddr, family,
-					      xfrm[i]->props.output_mark);
+					      &saddr, &daddr, family, mark);
 			err = PTR_ERR(dst);
 			if (IS_ERR(dst))
 				goto put_states;

net/xfrm/xfrm_user.c

@@ -527,6 +527,19 @@ static void xfrm_update_ae_params(struct xfrm_state *x, struct nlattr **attrs,
 		x->replay_maxdiff = nla_get_u32(rt);
 }
 
+static void xfrm_smark_init(struct nlattr **attrs, struct xfrm_mark *m)
+{
+	if (attrs[XFRMA_SET_MARK]) {
+		m->v = nla_get_u32(attrs[XFRMA_SET_MARK]);
+		if (attrs[XFRMA_SET_MARK_MASK])
+			m->m = nla_get_u32(attrs[XFRMA_SET_MARK_MASK]);
+		else
+			m->m = 0xffffffff;
+	} else {
+		m->v = m->m = 0;
+	}
+}
+
 static struct xfrm_state *xfrm_state_construct(struct net *net,
 					       struct xfrm_usersa_info *p,
 					       struct nlattr **attrs,
@@ -579,8 +592,7 @@ static struct xfrm_state *xfrm_state_construct(struct net *net,
 
 	xfrm_mark_get(attrs, &x->mark);
 
-	if (attrs[XFRMA_OUTPUT_MARK])
-		x->props.output_mark = nla_get_u32(attrs[XFRMA_OUTPUT_MARK]);
+	xfrm_smark_init(attrs, &x->props.smark);
 
 	err = __xfrm_init_state(x, false, attrs[XFRMA_OFFLOAD_DEV]);
 	if (err)
@@ -824,6 +836,18 @@ static int copy_to_user_auth(struct xfrm_algo_auth *auth, struct sk_buff *skb)
 	return 0;
 }
 
+static int xfrm_smark_put(struct sk_buff *skb, struct xfrm_mark *m)
+{
+	int ret = 0;
+
+	if (m->v | m->m) {
+		ret = nla_put_u32(skb, XFRMA_SET_MARK, m->v);
+		if (!ret)
+			ret = nla_put_u32(skb, XFRMA_SET_MARK_MASK, m->m);
+	}
+	return ret;
+}
+
 /* Don't change this without updating xfrm_sa_len! */
 static int copy_to_user_state_extra(struct xfrm_state *x,
 				    struct xfrm_usersa_info *p,
@@ -887,6 +911,11 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
 	ret = xfrm_mark_put(skb, &x->mark);
 	if (ret)
 		goto out;
+
+	ret = xfrm_smark_put(skb, &x->props.smark);
+	if (ret)
+		goto out;
+
 	if (x->replay_esn)
 		ret = nla_put(skb, XFRMA_REPLAY_ESN_VAL,
 			      xfrm_replay_state_esn_len(x->replay_esn),
@@ -900,11 +929,7 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
 		ret = copy_user_offload(&x->xso, skb);
 	if (ret)
 		goto out;
-	if (x->props.output_mark) {
-		ret = nla_put_u32(skb, XFRMA_OUTPUT_MARK, x->props.output_mark);
-		if (ret)
-			goto out;
-	}
+
 	if (x->security)
 		ret = copy_sec_ctx(x->security, skb);
 out:
@@ -2493,7 +2518,8 @@ static const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
 	[XFRMA_PROTO]		= { .type = NLA_U8 },
 	[XFRMA_ADDRESS_FILTER]	= { .len = sizeof(struct xfrm_address_filter) },
 	[XFRMA_OFFLOAD_DEV]	= { .len = sizeof(struct xfrm_user_offload) },
-	[XFRMA_OUTPUT_MARK]	= { .type = NLA_U32 },
+	[XFRMA_SET_MARK]	= { .type = NLA_U32 },
+	[XFRMA_SET_MARK_MASK]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy xfrma_spd_policy[XFRMA_SPD_MAX+1] = {
@@ -2719,8 +2745,10 @@ static inline unsigned int xfrm_sa_len(struct xfrm_state *x)
 		l += nla_total_size(sizeof(x->props.extra_flags));
 	if (x->xso.dev)
 		 l += nla_total_size(sizeof(x->xso));
-	if (x->props.output_mark)
-		l += nla_total_size(sizeof(x->props.output_mark));
+	if (x->props.smark.v | x->props.smark.m) {
+		l += nla_total_size(sizeof(x->props.smark.v));
+		l += nla_total_size(sizeof(x->props.smark.m));
+	}
 
 	/* Must count x->lastused as it may become non-zero behind our back. */
 	l += nla_total_size_64bit(sizeof(u64));