xfrm: make xfrm modes builtin

after previous changes, xfrm_mode contains no function pointers anymore
and all modules defining such struct contain no code except an init/exit
functions to register the xfrm_mode struct with the xfrm core.

Just place the xfrm modes core and remove the modules,
the run-time xfrm_mode register/unregister functionality is removed.

Before:

    text    data     bss      dec filename
    7523     200    2364    10087 net/xfrm/xfrm_input.o
   40003     628     440    41071 net/xfrm/xfrm_state.o
15730338 6937080 4046908 26714326 vmlinux

    7389     200    2364    9953  net/xfrm/xfrm_input.o
   40574     656     440   41670  net/xfrm/xfrm_state.o
15730084 6937068 4046908 26714060 vmlinux

The xfrm*_mode_{transport,tunnel,beet} modules are gone.

v2: replace CONFIG_INET6_XFRM_MODE_* IS_ENABLED guards with CONFIG_IPV6
    ones rather than removing them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

5 files changed, 73 insertions, 117 deletions

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 74b53c13279b..b5a31c8e2088 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -351,7 +351,7 @@ xfrm_inner_mode_encap_remove(struct xfrm_state *x,
 
 static int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 {
-	struct xfrm_mode *inner_mode = x->inner_mode;
+	const struct xfrm_mode *inner_mode = x->inner_mode;
 	const struct xfrm_state_afinfo *afinfo;
 	int err = -EAFNOSUPPORT;
 
@@ -394,7 +394,6 @@ static int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
  */
 static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 {
-#if IS_ENABLED(CONFIG_INET_XFRM_MODE_TRANSPORT)
 	int ihl = skb->data - skb_transport_header(skb);
 
 	if (skb->transport_header != skb->network_header) {
@@ -405,14 +404,11 @@ static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 	ip_hdr(skb)->tot_len = htons(skb->len + ihl);
 	skb_reset_transport_header(skb);
 	return 0;
-#else
-	return -EOPNOTSUPP;
-#endif
 }
 
 static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 {
-#if IS_ENABLED(CONFIG_INET6_XFRM_MODE_TRANSPORT)
+#if IS_ENABLED(CONFIG_IPV6)
 	int ihl = skb->data - skb_transport_header(skb);
 
 	if (skb->transport_header != skb->network_header) {
@@ -425,7 +421,8 @@ static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 	skb_reset_transport_header(skb);
 	return 0;
 #else
-	return -EOPNOTSUPP;
+	WARN_ON_ONCE(1);
+	return -EAFNOSUPPORT;
 #endif
 }
 
@@ -458,12 +455,12 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 {
 	const struct xfrm_state_afinfo *afinfo;
 	struct net *net = dev_net(skb->dev);
+	const struct xfrm_mode *inner_mode;
 	int err;
 	__be32 seq;
 	__be32 seq_hi;
 	struct xfrm_state *x = NULL;
 	xfrm_address_t *daddr;
-	struct xfrm_mode *inner_mode;
 	u32 mark = skb->mark;
 	unsigned int family = AF_UNSPEC;
 	int decaps = 0;
diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index 93efb0965e7d..4fc49dbf3edf 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -244,8 +244,8 @@ static void xfrmi_scrub_packet(struct sk_buff *skb, bool xnet)
 
 static int xfrmi_rcv_cb(struct sk_buff *skb, int err)
 {
+	const struct xfrm_mode *inner_mode;
 	struct pcpu_sw_netstats *tstats;
-	struct xfrm_mode *inner_mode;
 	struct net_device *dev;
 	struct xfrm_state *x;
 	struct xfrm_if *xi;
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 17c4f58d28ea..3cb2a328a8ab 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -61,7 +61,6 @@ static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
  */
 static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 {
-#if IS_ENABLED(CONFIG_INET_XFRM_MODE_TRANSPORT)
 	struct iphdr *iph = ip_hdr(skb);
 	int ihl = iph->ihl * 4;
 
@@ -74,10 +73,6 @@ static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 	__skb_pull(skb, ihl);
 	memmove(skb_network_header(skb), iph, ihl);
 	return 0;
-#else
-	WARN_ON_ONCE(1);
-	return -EOPNOTSUPP;
-#endif
 }
 
 /* Add encapsulation header.
@@ -87,7 +82,7 @@ static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
  */
 static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 {
-#if IS_ENABLED(CONFIG_INET6_XFRM_MODE_TRANSPORT)
+#if IS_ENABLED(CONFIG_IPV6)
 	struct ipv6hdr *iph;
 	u8 *prevhdr;
 	int hdr_len;
@@ -107,7 +102,7 @@ static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 	return 0;
 #else
 	WARN_ON_ONCE(1);
-	return -EOPNOTSUPP;
+	return -EAFNOSUPPORT;
 #endif
 }
 
@@ -118,7 +113,7 @@ static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
  */
 static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
 {
-#if IS_ENABLED(CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION)
+#if IS_ENABLED(CONFIG_IPV6)
 	struct ipv6hdr *iph;
 	u8 *prevhdr;
 	int hdr_len;
@@ -140,7 +135,7 @@ static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
 	return 0;
 #else
 	WARN_ON_ONCE(1);
-	return -EOPNOTSUPP;
+	return -EAFNOSUPPORT;
 #endif
 }
 
@@ -624,7 +619,7 @@ EXPORT_SYMBOL_GPL(xfrm_output);
 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 {
 	const struct xfrm_state_afinfo *afinfo;
-	struct xfrm_mode *inner_mode;
+	const struct xfrm_mode *inner_mode;
 	int err = -EAFNOSUPPORT;
 
 	if (x->sel.family == AF_UNSPEC)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 67122beb116c..1a5fd2296556 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2546,10 +2546,10 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
 					    struct dst_entry *dst)
 {
 	const struct xfrm_state_afinfo *afinfo;
+	const struct xfrm_mode *inner_mode;
 	struct net *net = xp_net(policy);
 	unsigned long now = jiffies;
 	struct net_device *dev;
-	struct xfrm_mode *inner_mode;
 	struct xfrm_dst *xdst_prev = NULL;
 	struct xfrm_dst *xdst0 = NULL;
 	int i = 0;
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 358b09f0d018..ace26f6dc790 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -330,92 +330,67 @@ static void xfrm_put_type_offload(const struct xfrm_type_offload *type)
 	module_put(type->owner);
 }
 
-static DEFINE_SPINLOCK(xfrm_mode_lock);
-int xfrm_register_mode(struct xfrm_mode *mode)
-{
-	struct xfrm_state_afinfo *afinfo;
-	struct xfrm_mode **modemap;
-	int err;
-
-	if (unlikely(mode->encap >= XFRM_MODE_MAX))
-		return -EINVAL;
-
-	afinfo = xfrm_state_get_afinfo(mode->family);
-	if (unlikely(afinfo == NULL))
-		return -EAFNOSUPPORT;
-
-	err = -EEXIST;
-	modemap = afinfo->mode_map;
-	spin_lock_bh(&xfrm_mode_lock);
-	if (modemap[mode->encap])
-		goto out;
-
-	err = -ENOENT;
-	if (!try_module_get(afinfo->owner))
-		goto out;
-
-	modemap[mode->encap] = mode;
-	err = 0;
-
-out:
-	spin_unlock_bh(&xfrm_mode_lock);
-	rcu_read_unlock();
-	return err;
-}
-EXPORT_SYMBOL(xfrm_register_mode);
-
-void xfrm_unregister_mode(struct xfrm_mode *mode)
-{
-	struct xfrm_state_afinfo *afinfo;
-	struct xfrm_mode **modemap;
-
-	afinfo = xfrm_state_get_afinfo(mode->family);
-	if (WARN_ON_ONCE(!afinfo))
-		return;
-
-	modemap = afinfo->mode_map;
-	spin_lock_bh(&xfrm_mode_lock);
-	if (likely(modemap[mode->encap] == mode)) {
-		modemap[mode->encap] = NULL;
-		module_put(afinfo->owner);
-	}
-
-	spin_unlock_bh(&xfrm_mode_lock);
-	rcu_read_unlock();
-}
-EXPORT_SYMBOL(xfrm_unregister_mode);
-
-static struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
-{
-	struct xfrm_state_afinfo *afinfo;
-	struct xfrm_mode *mode;
-	int modload_attempted = 0;
+static const struct xfrm_mode xfrm4_mode_map[XFRM_MODE_MAX] = {
+	[XFRM_MODE_BEET] = {
+		.encap = XFRM_MODE_BEET,
+		.flags = XFRM_MODE_FLAG_TUNNEL,
+		.family = AF_INET,
+	},
+	[XFRM_MODE_TRANSPORT] = {
+		.encap = XFRM_MODE_TRANSPORT,
+		.family = AF_INET,
+	},
+	[XFRM_MODE_TUNNEL] = {
+		.encap = XFRM_MODE_TUNNEL,
+		.flags = XFRM_MODE_FLAG_TUNNEL,
+		.family = AF_INET,
+	},
+};
+
+static const struct xfrm_mode xfrm6_mode_map[XFRM_MODE_MAX] = {
+	[XFRM_MODE_BEET] = {
+		.encap = XFRM_MODE_BEET,
+		.flags = XFRM_MODE_FLAG_TUNNEL,
+		.family = AF_INET6,
+	},
+	[XFRM_MODE_ROUTEOPTIMIZATION] = {
+		.encap = XFRM_MODE_ROUTEOPTIMIZATION,
+		.family = AF_INET6,
+	},
+	[XFRM_MODE_TRANSPORT] = {
+		.encap = XFRM_MODE_TRANSPORT,
+		.family = AF_INET6,
+	},
+	[XFRM_MODE_TUNNEL] = {
+		.encap = XFRM_MODE_TUNNEL,
+		.flags = XFRM_MODE_FLAG_TUNNEL,
+		.family = AF_INET6,
+	},
+};
+
+static const struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
+{
+	const struct xfrm_mode *mode;
 
 	if (unlikely(encap >= XFRM_MODE_MAX))
 		return NULL;
 
-retry:
-	afinfo = xfrm_state_get_afinfo(family);
-	if (unlikely(afinfo == NULL))
-		return NULL;
-
-	mode = READ_ONCE(afinfo->mode_map[encap]);
-	if (unlikely(mode && !try_module_get(mode->owner)))
-		mode = NULL;
-
-	rcu_read_unlock();
-	if (!mode && !modload_attempted) {
-		request_module("xfrm-mode-%d-%d", family, encap);
-		modload_attempted = 1;
-		goto retry;
+	switch (family) {
+	case AF_INET:
+		mode = &xfrm4_mode_map[encap];
+		if (mode->family == family)
+			return mode;
+		break;
+	case AF_INET6:
+		mode = &xfrm6_mode_map[encap];
+		if (mode->family == family)
+			return mode;
+		break;
+	default:
+		break;
 	}
 
-	return mode;
-}
-
-static void xfrm_put_mode(struct xfrm_mode *mode)
-{
-	module_put(mode->owner);
+	return NULL;
 }
 
 void xfrm_state_free(struct xfrm_state *x)
@@ -436,12 +411,6 @@ static void ___xfrm_state_destroy(struct xfrm_state *x)
 	kfree(x->coaddr);
 	kfree(x->replay_esn);
 	kfree(x->preplay_esn);
-	if (x->inner_mode)
-		xfrm_put_mode(x->inner_mode);
-	if (x->inner_mode_iaf)
-		xfrm_put_mode(x->inner_mode_iaf);
-	if (x->outer_mode)
-		xfrm_put_mode(x->outer_mode);
 	if (x->type_offload)
 		xfrm_put_type_offload(x->type_offload);
 	if (x->type) {
@@ -2235,8 +2204,8 @@ int xfrm_state_mtu(struct xfrm_state *x, int mtu)
 
 int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload)
 {
-	struct xfrm_state_afinfo *afinfo;
-	struct xfrm_mode *inner_mode;
+	const struct xfrm_mode *inner_mode;
+	const struct xfrm_state_afinfo *afinfo;
 	int family = x->props.family;
 	int err;
 
@@ -2262,24 +2231,21 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload)
 			goto error;
 
 		if (!(inner_mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
-		    family != x->sel.family) {
-			xfrm_put_mode(inner_mode);
+		    family != x->sel.family)
 			goto error;
-		}
 
 		x->inner_mode = inner_mode;
 	} else {
-		struct xfrm_mode *inner_mode_iaf;
+		const struct xfrm_mode *inner_mode_iaf;
 		int iafamily = AF_INET;
 
 		inner_mode = xfrm_get_mode(x->props.mode, x->props.family);
 		if (inner_mode == NULL)
 			goto error;
 
-		if (!(inner_mode->flags & XFRM_MODE_FLAG_TUNNEL)) {
-			xfrm_put_mode(inner_mode);
+		if (!(inner_mode->flags & XFRM_MODE_FLAG_TUNNEL))
 			goto error;
-		}
+
 		x->inner_mode = inner_mode;
 
 		if (x->props.family == AF_INET)
@@ -2289,8 +2255,6 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload)
 		if (inner_mode_iaf) {
 			if (inner_mode_iaf->flags & XFRM_MODE_FLAG_TUNNEL)
 				x->inner_mode_iaf = inner_mode_iaf;
-			else
-				xfrm_put_mode(inner_mode_iaf);
 		}
 	}