Commit 3328715e authored by Steffen Klassert's avatar Steffen Klassert

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: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 51adfcc3
......@@ -1347,6 +1347,18 @@ struct xfrm_algo_desc {
struct sadb_alg desc;
};
/* XFRM protocol handlers. */
struct xfrm4_protocol {
int (*handler)(struct sk_buff *skb);
int (*input_handler)(struct sk_buff *skb, int nexthdr, __be32 spi,
int encap_type);
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);
......@@ -1498,13 +1510,18 @@ int xfrm4_rcv(struct sk_buff *skb);
static inline int xfrm4_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
{
return xfrm4_rcv_encap(skb, nexthdr, spi, 0);
XFRM_SPI_SKB_CB(skb)->family = AF_INET;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
return xfrm_input(skb, nexthdr, spi, 0);
}
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);
int 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);
......@@ -1752,4 +1769,16 @@ static inline int xfrm_mark_put(struct sk_buff *skb, const struct xfrm_mark *m)
return ret;
}
static inline int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family,
u8 protocol, int err)
{
switch(family) {
#ifdef CONFIG_INET
case AF_INET:
return xfrm4_rcv_cb(skb, protocol, err);
#endif
}
return 0;
}
#endif /* _NET_XFRM_H */
......@@ -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
......@@ -37,15 +37,6 @@ drop:
return NET_RX_DROP;
}
int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
int encap_type)
{
XFRM_SPI_SKB_CB(skb)->family = AF_INET;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
return xfrm_input(skb, nexthdr, spi, encap_type);
}
EXPORT_SYMBOL(xfrm4_rcv_encap);
int xfrm4_transport_finish(struct sk_buff *skb, int async)
{
struct iphdr *iph = ip_hdr(skb);
......
/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
*
* Copyright (C) 2013 secunet Security Networks AG
*
* Author:
* Steffen Klassert <steffen.klassert@secunet.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 struct xfrm4_protocol __rcu *ipcomp4_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;
case IPPROTO_COMP:
return &ipcomp4_handlers;
}
return NULL;
}
#define for_each_protocol_rcu(head, handler) \
for (handler = rcu_dereference(head); \
handler != NULL; \
handler = rcu_dereference(handler->next)) \
int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
{
int ret;
struct xfrm4_protocol *handler;
for_each_protocol_rcu(*proto_handlers(protocol), handler)
if ((ret = handler->cb_handler(skb, err)) <= 0)
return ret;
return 0;
}
EXPORT_SYMBOL(xfrm4_rcv_cb);
int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
int encap_type)
{
int ret;
struct xfrm4_protocol *handler;
XFRM_SPI_SKB_CB(skb)->family = AF_INET;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
for_each_protocol_rcu(*proto_handlers(nexthdr), handler)
if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
return ret;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL(xfrm4_rcv_encap);
static int xfrm4_esp_rcv(struct sk_buff *skb)
{
int ret;
struct xfrm4_protocol *handler;
for_each_protocol_rcu(esp4_handlers, handler)
if ((ret = handler->handler(skb)) != -EINVAL)
return ret;
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)
{
int ret;
struct xfrm4_protocol *handler;
for_each_protocol_rcu(ah4_handlers, handler)
if ((ret = handler->handler(skb)) != -EINVAL)
return ret;;
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 int xfrm4_ipcomp_rcv(struct sk_buff *skb)
{
int ret;
struct xfrm4_protocol *handler;
for_each_protocol_rcu(ipcomp4_handlers, handler)
if ((ret = handler->handler(skb)) != -EINVAL)
return ret;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
kfree_skb(skb);
return 0;
}
static void xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
{
struct xfrm4_protocol *handler;
for_each_protocol_rcu(ipcomp4_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 const struct net_protocol ipcomp4_protocol = {
.handler = xfrm4_ipcomp_rcv,
.err_handler = xfrm4_ipcomp_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;
case IPPROTO_COMP:
return &ipcomp4_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;
mutex_lock(&xfrm4_protocol_mutex);
if (!rcu_dereference_protected(*proto_handlers(protocol),
lockdep_is_held(&xfrm4_protocol_mutex)))
add_netproto = true;
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;
}
}
if (!rcu_dereference_protected(*proto_handlers(protocol),
lockdep_is_held(&xfrm4_protocol_mutex))) {
if (inet_del_protocol(netproto(protocol), protocol) < 0) {
pr_err("%s: can't remove protocol\n", __func__);
ret = -EAGAIN;
}
}
mutex_unlock(&xfrm4_protocol_mutex);
synchronize_net();
return ret;
}
EXPORT_SYMBOL(xfrm4_protocol_deregister);
......@@ -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;
......@@ -120,9 +120,14 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
async = 1;
x = xfrm_input_state(skb);
seq = XFRM_SKB_CB(skb)->seq.input.low;
family = x->outer_mode->afinfo->family;
goto resume;
}
daddr = (xfrm_address_t *)(skb_network_header(skb) +
XFRM_SPI_SKB_CB(skb)->daddroff);
family = XFRM_SPI_SKB_CB(skb)->family;
/* Allocate new secpath or COW existing one. */
if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
struct sec_path *sp;
......@@ -137,10 +142,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
skb->sp = sp;
}
daddr = (xfrm_address_t *)(skb_network_header(skb) +
XFRM_SPI_SKB_CB(skb)->daddroff);
family = XFRM_SPI_SKB_CB(skb)->family;
seq = 0;
if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
......@@ -201,7 +202,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
if (nexthdr == -EINPROGRESS)
return 0;
resume:
spin_lock(&x->lock);
if (nexthdr <= 0) {
......@@ -263,6 +263,10 @@ resume:
}
} while (!err);
err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
if (err)
goto drop;
nf_reset(skb);
if (decaps) {
......@@ -276,6 +280,7 @@ resume:
drop_unlock:
spin_unlock(&x->lock);
drop:
xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
kfree_skb(skb);
return 0;
}
......
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