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Message-ID: <20131205120100.GX31491@secunet.com>
Date: Thu, 5 Dec 2013 13:01:00 +0100
From: Steffen Klassert <steffen.klassert@...unet.com>
To: netdev@...r.kernel.org
Cc: Christophe Gouault <christophe.gouault@...nd.com>,
Saurabh Mohan <saurabh.mohan@...tta.com>
Subject: [PATCH RFC 1/9] xfrm4: Add IPsec protocol multiplexer
This patch add an IPsec protocol multiplexer. With this
it is possible to add alternative protocol handlers as
needed for IPsec virtual tunnel interfaces.
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
include/net/xfrm.h | 14 ++++
net/ipv4/Makefile | 2 +-
net/ipv4/xfrm4_protocol.c | 205 +++++++++++++++++++++++++++++++++++++++++++++
net/xfrm/xfrm_input.c | 9 +-
4 files changed, 227 insertions(+), 3 deletions(-)
create mode 100644 net/ipv4/xfrm4_protocol.c
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 6b82fdf..7f71462 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1348,6 +1348,17 @@ struct xfrm_algo_desc {
struct sadb_alg desc;
};
+
+/* XFRM protocol handlers. */
+struct xfrm4_protocol {
+ int (*handler)(struct sk_buff *skb);
+ int (*cb_handler)(struct sk_buff *skb, int err);
+ int (*err_handler)(struct sk_buff *skb, u32 info);
+
+ struct xfrm4_protocol __rcu *next;
+ int priority;
+};
+
/* XFRM tunnel handlers. */
struct xfrm_tunnel {
int (*handler)(struct sk_buff *skb);
@@ -1503,6 +1514,9 @@ int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb);
int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb);
int xfrm4_output(struct sk_buff *skb);
int xfrm4_output_finish(struct sk_buff *skb);
+void xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err);
+int xfrm4_protocol_register(struct xfrm4_protocol *handler, unsigned char protocol);
+int xfrm4_protocol_deregister(struct xfrm4_protocol *handler, unsigned char protocol);
int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family);
int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family);
void xfrm4_local_error(struct sk_buff *skb, u32 mtu);
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 4b81e91..4a73d5c 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -55,4 +55,4 @@ obj-$(CONFIG_MEMCG_KMEM) += tcp_memcontrol.o
obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
- xfrm4_output.o
+ xfrm4_output.o xfrm4_protocol.o
diff --git a/net/ipv4/xfrm4_protocol.c b/net/ipv4/xfrm4_protocol.c
new file mode 100644
index 0000000..8a9e0d7
--- /dev/null
+++ b/net/ipv4/xfrm4_protocol.c
@@ -0,0 +1,205 @@
+/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
+ *
+ * Copyright (C) 2013 secunet Security Networks AG
+ *
+ * Author:
+ * Steffen Klassert <steffen.klassert@...unet.com>
+ *
+ * Based on:
+ * net/ipv4/tunnel4.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/skbuff.h>
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/xfrm.h>
+
+static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
+static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
+static DEFINE_MUTEX(xfrm4_protocol_mutex);
+
+static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
+{
+ switch (protocol) {
+ case IPPROTO_ESP:
+ return &esp4_handlers;
+ case IPPROTO_AH:
+ return &ah4_handlers;
+ }
+
+ return NULL;
+}
+
+#define for_each_protocol_rcu(head, handler) \
+ for (handler = rcu_dereference(head); \
+ handler != NULL; \
+ handler = rcu_dereference(handler->next)) \
+
+void xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
+{
+ struct xfrm4_protocol *handler;
+
+ for_each_protocol_rcu(*proto_handlers(protocol), handler)
+ if (!handler->cb_handler(skb, err))
+ return;
+}
+EXPORT_SYMBOL(xfrm4_rcv_cb);
+
+static int xfrm4_esp_rcv(struct sk_buff *skb)
+{
+ struct xfrm4_protocol *handler;
+
+ for_each_protocol_rcu(esp4_handlers, handler)
+ if (!handler->handler(skb))
+ return 0;
+
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+
+ kfree_skb(skb);
+ return 0;
+}
+
+static void xfrm4_esp_err(struct sk_buff *skb, u32 info)
+{
+ struct xfrm4_protocol *handler;
+
+ for_each_protocol_rcu(esp4_handlers, handler)
+ if (!handler->err_handler(skb, info))
+ break;
+}
+
+static int xfrm4_ah_rcv(struct sk_buff *skb)
+{
+ struct xfrm4_protocol *handler;
+
+ for_each_protocol_rcu(esp4_handlers, handler)
+ if (!handler->handler(skb))
+ return 0;
+
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+
+ kfree_skb(skb);
+ return 0;
+}
+
+static void xfrm4_ah_err(struct sk_buff *skb, u32 info)
+{
+ struct xfrm4_protocol *handler;
+
+ for_each_protocol_rcu(ah4_handlers, handler)
+ if (!handler->err_handler(skb, info))
+ break;
+}
+
+static const struct net_protocol esp4_protocol = {
+ .handler = xfrm4_esp_rcv,
+ .err_handler = xfrm4_esp_err,
+ .no_policy = 1,
+ .netns_ok = 1,
+};
+
+static const struct net_protocol ah4_protocol = {
+ .handler = xfrm4_ah_rcv,
+ .err_handler = xfrm4_ah_err,
+ .no_policy = 1,
+ .netns_ok = 1,
+};
+
+static inline const struct net_protocol *netproto(unsigned char protocol)
+{
+ switch (protocol) {
+ case IPPROTO_ESP:
+ return &esp4_protocol;
+ case IPPROTO_AH:
+ return &ah4_protocol;
+ }
+
+ return NULL;
+}
+
+int xfrm4_protocol_register(struct xfrm4_protocol *handler,
+ unsigned char protocol)
+{
+ struct xfrm4_protocol __rcu **pprev;
+ struct xfrm4_protocol *t;
+ bool add_netproto = false;
+
+ int ret = -EEXIST;
+ int priority = handler->priority;
+
+ if (!rcu_dereference(*proto_handlers(protocol)))
+ add_netproto = true;
+
+ mutex_lock(&xfrm4_protocol_mutex);
+
+ for (pprev = proto_handlers(protocol);
+ (t = rcu_dereference_protected(*pprev,
+ lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
+ pprev = &t->next) {
+ if (t->priority < priority)
+ break;
+ if (t->priority == priority)
+ goto err;
+ }
+
+ handler->next = *pprev;
+ rcu_assign_pointer(*pprev, handler);
+
+ ret = 0;
+
+err:
+ mutex_unlock(&xfrm4_protocol_mutex);
+
+ if (add_netproto) {
+ if (inet_add_protocol(netproto(protocol), protocol)) {
+ pr_err("%s: can't add protocol\n", __func__);
+ ret = -EAGAIN;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(xfrm4_protocol_register);
+
+int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
+ unsigned char protocol)
+{
+ struct xfrm4_protocol __rcu **pprev;
+ struct xfrm4_protocol *t;
+ int ret = -ENOENT;
+
+ mutex_lock(&xfrm4_protocol_mutex);
+
+ for (pprev = proto_handlers(protocol);
+ (t = rcu_dereference_protected(*pprev,
+ lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
+ pprev = &t->next) {
+ if (t == handler) {
+ *pprev = handler->next;
+ ret = 0;
+ break;
+ }
+ }
+
+ mutex_unlock(&xfrm4_protocol_mutex);
+
+ if (!rcu_dereference(*proto_handlers(protocol))) {
+ if (inet_del_protocol(netproto(protocol), protocol) < 0) {
+ pr_err("%s: can't remove protocol\n", __func__);
+ ret = -EAGAIN;
+ }
+ }
+
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL(xfrm4_protocol_deregister);
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 8884399..dc3066e 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -108,7 +108,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
int err;
__be32 seq;
__be32 seq_hi;
- struct xfrm_state *x;
+ struct xfrm_state *x = NULL;
xfrm_address_t *daddr;
struct xfrm_mode *inner_mode;
unsigned int family;
@@ -199,8 +199,10 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
nexthdr = x->type->input(x, skb);
- if (nexthdr == -EINPROGRESS)
+ if (nexthdr == -EINPROGRESS) {
+ xfrm4_rcv_cb(skb, x->type->proto, nexthdr);
return 0;
+ }
resume:
spin_lock(&x->lock);
@@ -263,6 +265,8 @@ resume:
}
} while (!err);
+ xfrm4_rcv_cb(skb, x->type->proto, 0);
+
nf_reset(skb);
if (decaps) {
@@ -276,6 +280,7 @@ resume:
drop_unlock:
spin_unlock(&x->lock);
drop:
+ xfrm4_rcv_cb(skb, x ? x->type->proto : nexthdr, -1);
kfree_skb(skb);
return 0;
}
--
1.7.9.5
--
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