[IPSEC] xfrm: Abstract out encapsulation modes
Herbert Xu [Sun, 28 May 2006 06:05:54 +0000 (23:05 -0700)]
This patch adds the structure xfrm_mode.  It is meant to represent
the operations carried out by transport/tunnel modes.

By doing this we allow additional encapsulation modes to be added
without clogging up the xfrm_input/xfrm_output paths.

Candidate modes include 4-to-6 tunnel mode, 6-to-4 tunnel mode, and
BEET modes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

17 files changed:
include/linux/xfrm.h
include/net/xfrm.h
net/ipv4/Kconfig
net/ipv4/Makefile
net/ipv4/xfrm4_input.c
net/ipv4/xfrm4_mode_transport.c [new file with mode: 0644]
net/ipv4/xfrm4_mode_tunnel.c [new file with mode: 0644]
net/ipv4/xfrm4_output.c
net/ipv6/Kconfig
net/ipv6/Makefile
net/ipv6/ip6_output.c
net/ipv6/xfrm6_input.c
net/ipv6/xfrm6_mode_transport.c [new file with mode: 0644]
net/ipv6/xfrm6_mode_tunnel.c [new file with mode: 0644]
net/ipv6/xfrm6_output.c
net/xfrm/xfrm_policy.c
net/xfrm/xfrm_state.c

index 6b42cc4..46a15c7 100644 (file)
@@ -118,6 +118,10 @@ enum
        XFRM_SHARE_UNIQUE       /* Use once */
 };
 
+#define XFRM_MODE_TRANSPORT 0
+#define XFRM_MODE_TUNNEL 1
+#define XFRM_MODE_MAX 2
+
 /* Netlink configuration messages.  */
 enum {
        XFRM_MSG_BASE = 0x10,
index ed7c974..ed5bb34 100644 (file)
@@ -20,6 +20,8 @@
 #include <net/ip6_fib.h>
 
 #define XFRM_ALIGN8(len)       (((len) + 7) & ~7)
+#define MODULE_ALIAS_XFRM_MODE(family, encap) \
+       MODULE_ALIAS("xfrm-mode-" __stringify(family) "-" __stringify(encap))
 
 extern struct sock *xfrm_nl;
 extern u32 sysctl_xfrm_aevent_etime;
@@ -164,6 +166,7 @@ struct xfrm_state
        /* Reference to data common to all the instances of this
         * transformer. */
        struct xfrm_type        *type;
+       struct xfrm_mode        *mode;
 
        /* Security context */
        struct xfrm_sec_ctx     *security;
@@ -205,6 +208,7 @@ struct xfrm_dst;
 struct xfrm_policy_afinfo {
        unsigned short          family;
        struct xfrm_type        *type_map[256];
+       struct xfrm_mode        *mode_map[XFRM_MODE_MAX];
        struct dst_ops          *dst_ops;
        void                    (*garbage_collect)(void);
        int                     (*dst_lookup)(struct xfrm_dst **dst, struct flowi *fl);
@@ -267,6 +271,19 @@ extern int xfrm_unregister_type(struct xfrm_type *type, unsigned short family);
 extern struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family);
 extern void xfrm_put_type(struct xfrm_type *type);
 
+struct xfrm_mode {
+       int (*input)(struct xfrm_state *x, struct sk_buff *skb);
+       int (*output)(struct sk_buff *skb);
+
+       struct module *owner;
+       unsigned int encap;
+};
+
+extern int xfrm_register_mode(struct xfrm_mode *mode, int family);
+extern int xfrm_unregister_mode(struct xfrm_mode *mode, int family);
+extern struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family);
+extern void xfrm_put_mode(struct xfrm_mode *mode);
+
 struct xfrm_tmpl
 {
 /* id in template is interpreted as:
index e40f753..35eb70b 100644 (file)
@@ -414,6 +414,24 @@ config INET_TUNNEL
        tristate
        default n
 
+config INET_XFRM_MODE_TRANSPORT
+       tristate "IP: IPsec transport mode"
+       default y
+       select XFRM
+       ---help---
+         Support for IPsec transport mode.
+
+         If unsure, say Y.
+
+config INET_XFRM_MODE_TUNNEL
+       tristate "IP: IPsec tunnel mode"
+       default y
+       select XFRM
+       ---help---
+         Support for IPsec tunnel mode.
+
+         If unsure, say Y.
+
 config INET_DIAG
        tristate "INET: socket monitoring interface"
        default y
index 9ef50a0..4cc9448 100644 (file)
@@ -24,6 +24,8 @@ obj-$(CONFIG_INET_ESP) += esp4.o
 obj-$(CONFIG_INET_IPCOMP) += ipcomp.o
 obj-$(CONFIG_INET_XFRM_TUNNEL) += xfrm4_tunnel.o
 obj-$(CONFIG_INET_TUNNEL) += tunnel4.o
+obj-$(CONFIG_INET_XFRM_MODE_TRANSPORT) += xfrm4_mode_transport.o
+obj-$(CONFIG_INET_XFRM_MODE_TUNNEL) += xfrm4_mode_tunnel.o
 obj-$(CONFIG_IP_PNP) += ipconfig.o
 obj-$(CONFIG_IP_ROUTE_MULTIPATH_RR) += multipath_rr.o
 obj-$(CONFIG_IP_ROUTE_MULTIPATH_RANDOM) += multipath_random.o
index 3e174c8..817ed84 100644 (file)
@@ -13,7 +13,6 @@
 #include <linux/string.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
-#include <net/inet_ecn.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
 
@@ -24,15 +23,6 @@ int xfrm4_rcv(struct sk_buff *skb)
 
 EXPORT_SYMBOL(xfrm4_rcv);
 
-static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
-{
-       struct iphdr *outer_iph = skb->nh.iph;
-       struct iphdr *inner_iph = skb->h.ipiph;
-
-       if (INET_ECN_is_ce(outer_iph->tos))
-               IP_ECN_set_ce(inner_iph);
-}
-
 static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
 {
        switch (nexthdr) {
@@ -113,24 +103,10 @@ int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
 
                xfrm_vec[xfrm_nr++] = x;
 
-               iph = skb->nh.iph;
+               if (x->mode->input(x, skb))
+                       goto drop;
 
                if (x->props.mode) {
-                       if (iph->protocol != IPPROTO_IPIP)
-                               goto drop;
-                       if (!pskb_may_pull(skb, sizeof(struct iphdr)))
-                               goto drop;
-                       if (skb_cloned(skb) &&
-                           pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
-                               goto drop;
-                       if (x->props.flags & XFRM_STATE_DECAP_DSCP)
-                               ipv4_copy_dscp(iph, skb->h.ipiph);
-                       if (!(x->props.flags & XFRM_STATE_NOECN))
-                               ipip_ecn_decapsulate(skb);
-                       skb->mac.raw = memmove(skb->data - skb->mac_len,
-                                              skb->mac.raw, skb->mac_len);
-                       skb->nh.raw = skb->data;
-                       memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
                        decaps = 1;
                        break;
                }
diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
new file mode 100644 (file)
index 0000000..e46d9a4
--- /dev/null
@@ -0,0 +1,69 @@
+/*
+ * xfrm4_mode_transport.c - Transport mode encapsulation for IPv4.
+ *
+ * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stringify.h>
+#include <net/dst.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+
+/* Add encapsulation header.
+ *
+ * The IP header will be moved forward to make space for the encapsulation
+ * header.
+ *
+ * On exit, skb->h will be set to the start of the payload to be processed
+ * by x->type->output and skb->nh will be set to the top IP header.
+ */
+static int xfrm4_transport_output(struct sk_buff *skb)
+{
+       struct xfrm_state *x;
+       struct iphdr *iph;
+       int ihl;
+
+       iph = skb->nh.iph;
+       skb->h.ipiph = iph;
+
+       ihl = iph->ihl * 4;
+       skb->h.raw += ihl;
+
+       x = skb->dst->xfrm;
+       skb->nh.raw = memmove(skb_push(skb, x->props.header_len), iph, ihl);
+       return 0;
+}
+
+static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+       return 0;
+}
+
+static struct xfrm_mode xfrm4_transport_mode = {
+       .input = xfrm4_transport_input,
+       .output = xfrm4_transport_output,
+       .owner = THIS_MODULE,
+       .encap = XFRM_MODE_TRANSPORT,
+};
+
+static int __init xfrm4_transport_init(void)
+{
+       return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
+}
+
+static void __exit xfrm4_transport_exit(void)
+{
+       int err;
+
+       err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
+       BUG_ON(err);
+}
+
+module_init(xfrm4_transport_init);
+module_exit(xfrm4_transport_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
new file mode 100644 (file)
index 0000000..f8d880b
--- /dev/null
@@ -0,0 +1,125 @@
+/*
+ * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
+ *
+ * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stringify.h>
+#include <net/dst.h>
+#include <net/inet_ecn.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+
+static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
+{
+       struct iphdr *outer_iph = skb->nh.iph;
+       struct iphdr *inner_iph = skb->h.ipiph;
+
+       if (INET_ECN_is_ce(outer_iph->tos))
+               IP_ECN_set_ce(inner_iph);
+}
+
+/* Add encapsulation header.
+ *
+ * The top IP header will be constructed per RFC 2401.  The following fields
+ * in it shall be filled in by x->type->output:
+ *      tot_len
+ *      check
+ *
+ * On exit, skb->h will be set to the start of the payload to be processed
+ * by x->type->output and skb->nh will be set to the top IP header.
+ */
+static int xfrm4_tunnel_output(struct sk_buff *skb)
+{
+       struct dst_entry *dst = skb->dst;
+       struct xfrm_state *x = dst->xfrm;
+       struct iphdr *iph, *top_iph;
+       int flags;
+
+       iph = skb->nh.iph;
+       skb->h.ipiph = iph;
+
+       skb->nh.raw = skb_push(skb, x->props.header_len);
+       top_iph = skb->nh.iph;
+
+       top_iph->ihl = 5;
+       top_iph->version = 4;
+
+       /* DS disclosed */
+       top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
+
+       flags = x->props.flags;
+       if (flags & XFRM_STATE_NOECN)
+               IP_ECN_clear(top_iph);
+
+       top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
+               0 : (iph->frag_off & htons(IP_DF));
+       if (!top_iph->frag_off)
+               __ip_select_ident(top_iph, dst->child, 0);
+
+       top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
+
+       top_iph->saddr = x->props.saddr.a4;
+       top_iph->daddr = x->id.daddr.a4;
+       top_iph->protocol = IPPROTO_IPIP;
+
+       memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
+       return 0;
+}
+
+static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+       struct iphdr *iph = skb->nh.iph;
+       int err = -EINVAL;
+
+       if (iph->protocol != IPPROTO_IPIP)
+               goto out;
+       if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+               goto out;
+
+       if (skb_cloned(skb) &&
+           (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+               goto out;
+
+       if (x->props.flags & XFRM_STATE_DECAP_DSCP)
+               ipv4_copy_dscp(iph, skb->h.ipiph);
+       if (!(x->props.flags & XFRM_STATE_NOECN))
+               ipip_ecn_decapsulate(skb);
+       skb->mac.raw = memmove(skb->data - skb->mac_len,
+                              skb->mac.raw, skb->mac_len);
+       skb->nh.raw = skb->data;
+       memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
+       err = 0;
+
+out:
+       return err;
+}
+
+static struct xfrm_mode xfrm4_tunnel_mode = {
+       .input = xfrm4_tunnel_input,
+       .output = xfrm4_tunnel_output,
+       .owner = THIS_MODULE,
+       .encap = XFRM_MODE_TUNNEL,
+};
+
+static int __init xfrm4_tunnel_init(void)
+{
+       return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
+}
+
+static void __exit xfrm4_tunnel_exit(void)
+{
+       int err;
+
+       err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
+       BUG_ON(err);
+}
+
+module_init(xfrm4_tunnel_init);
+module_exit(xfrm4_tunnel_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);
index 4ef8efa..ac9d91d 100644 (file)
 #include <linux/skbuff.h>
 #include <linux/spinlock.h>
 #include <linux/netfilter_ipv4.h>
-#include <net/inet_ecn.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
 #include <net/icmp.h>
 
-/* Add encapsulation header.
- *
- * In transport mode, the IP header will be moved forward to make space
- * for the encapsulation header.
- *
- * In tunnel mode, the top IP header will be constructed per RFC 2401.
- * The following fields in it shall be filled in by x->type->output:
- *     tot_len
- *     check
- *
- * On exit, skb->h will be set to the start of the payload to be processed
- * by x->type->output and skb->nh will be set to the top IP header.
- */
-static void xfrm4_encap(struct sk_buff *skb)
-{
-       struct dst_entry *dst = skb->dst;
-       struct xfrm_state *x = dst->xfrm;
-       struct iphdr *iph, *top_iph;
-       int flags;
-
-       iph = skb->nh.iph;
-       skb->h.ipiph = iph;
-
-       skb->nh.raw = skb_push(skb, x->props.header_len);
-       top_iph = skb->nh.iph;
-
-       if (!x->props.mode) {
-               skb->h.raw += iph->ihl*4;
-               memmove(top_iph, iph, iph->ihl*4);
-               return;
-       }
-
-       top_iph->ihl = 5;
-       top_iph->version = 4;
-
-       /* DS disclosed */
-       top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
-
-       flags = x->props.flags;
-       if (flags & XFRM_STATE_NOECN)
-               IP_ECN_clear(top_iph);
-
-       top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
-               0 : (iph->frag_off & htons(IP_DF));
-       if (!top_iph->frag_off)
-               __ip_select_ident(top_iph, dst->child, 0);
-
-       top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
-
-       top_iph->saddr = x->props.saddr.a4;
-       top_iph->daddr = x->id.daddr.a4;
-       top_iph->protocol = IPPROTO_IPIP;
-
-       memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
-}
-
 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
 {
        int mtu, ret = 0;
@@ -121,7 +64,9 @@ static int xfrm4_output_one(struct sk_buff *skb)
                if (err)
                        goto error;
 
-               xfrm4_encap(skb);
+               err = x->mode->output(skb);
+               if (err)
+                       goto error;
 
                err = x->type->output(x, skb);
                if (err)
index f8a107a..e923d4d 100644 (file)
@@ -106,6 +106,26 @@ config INET6_TUNNEL
        tristate
        default n
 
+config INET6_XFRM_MODE_TRANSPORT
+       tristate "IPv6: IPsec transport mode"
+       depends on IPV6
+       default IPV6
+       select XFRM
+       ---help---
+         Support for IPsec transport mode.
+
+         If unsure, say Y.
+
+config INET6_XFRM_MODE_TUNNEL
+       tristate "IPv6: IPsec tunnel mode"
+       depends on IPV6
+       default IPV6
+       select XFRM
+       ---help---
+         Support for IPsec tunnel mode.
+
+         If unsure, say Y.
+
 config IPV6_TUNNEL
        tristate "IPv6: IPv6-in-IPv6 tunnel"
        select INET6_TUNNEL
index a760b09..386e0a6 100644 (file)
@@ -20,6 +20,8 @@ obj-$(CONFIG_INET6_ESP) += esp6.o
 obj-$(CONFIG_INET6_IPCOMP) += ipcomp6.o
 obj-$(CONFIG_INET6_XFRM_TUNNEL) += xfrm6_tunnel.o
 obj-$(CONFIG_INET6_TUNNEL) += tunnel6.o
+obj-$(CONFIG_INET6_XFRM_MODE_TRANSPORT) += xfrm6_mode_transport.o
+obj-$(CONFIG_INET6_XFRM_MODE_TUNNEL) += xfrm6_mode_tunnel.o
 obj-$(CONFIG_NETFILTER)        += netfilter/
 
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
index e460489..416f6e4 100644 (file)
@@ -39,6 +39,7 @@
 #include <linux/in6.h>
 #include <linux/tcp.h>
 #include <linux/route.h>
+#include <linux/module.h>
 
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv6.h>
@@ -488,6 +489,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 
        return offset;
 }
+EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
 
 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 {
index 00cfdee..0405d74 100644 (file)
 #include <linux/string.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv6.h>
-#include <net/dsfield.h>
-#include <net/inet_ecn.h>
-#include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/xfrm.h>
 
-static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
-{
-       struct ipv6hdr *outer_iph = skb->nh.ipv6h;
-       struct ipv6hdr *inner_iph = skb->h.ipv6h;
-
-       if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
-               IP6_ECN_set_ce(inner_iph);
-}
-
 int xfrm6_rcv_spi(struct sk_buff *skb, u32 spi)
 {
        int err;
@@ -81,21 +69,10 @@ int xfrm6_rcv_spi(struct sk_buff *skb, u32 spi)
 
                xfrm_vec[xfrm_nr++] = x;
 
+               if (x->mode->input(x, skb))
+                       goto drop;
+
                if (x->props.mode) { /* XXX */
-                       if (nexthdr != IPPROTO_IPV6)
-                               goto drop;
-                       if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
-                               goto drop;
-                       if (skb_cloned(skb) &&
-                           pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
-                               goto drop;
-                       if (x->props.flags & XFRM_STATE_DECAP_DSCP)
-                               ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
-                       if (!(x->props.flags & XFRM_STATE_NOECN))
-                               ipip6_ecn_decapsulate(skb);
-                       skb->mac.raw = memmove(skb->data - skb->mac_len,
-                                              skb->mac.raw, skb->mac_len);
-                       skb->nh.raw = skb->data;
                        decaps = 1;
                        break;
                }
diff --git a/net/ipv6/xfrm6_mode_transport.c b/net/ipv6/xfrm6_mode_transport.c
new file mode 100644 (file)
index 0000000..5efbbae
--- /dev/null
@@ -0,0 +1,73 @@
+/*
+ * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
+ *
+ * Copyright (C) 2002 USAGI/WIDE Project
+ * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stringify.h>
+#include <net/dst.h>
+#include <net/ipv6.h>
+#include <net/xfrm.h>
+
+/* Add encapsulation header.
+ *
+ * The IP header and mutable extension headers will be moved forward to make
+ * space for the encapsulation header.
+ *
+ * On exit, skb->h will be set to the start of the encapsulation header to be
+ * filled in by x->type->output and skb->nh will be set to the nextheader field
+ * of the extension header directly preceding the encapsulation header, or in
+ * its absence, that of the top IP header.  The value of skb->data will always
+ * point to the top IP header.
+ */
+static int xfrm6_transport_output(struct sk_buff *skb)
+{
+       struct xfrm_state *x = skb->dst->xfrm;
+       struct ipv6hdr *iph;
+       u8 *prevhdr;
+       int hdr_len;
+
+       skb_push(skb, x->props.header_len);
+       iph = skb->nh.ipv6h;
+
+       hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
+       skb->nh.raw = prevhdr - x->props.header_len;
+       skb->h.raw = skb->data + hdr_len;
+       memmove(skb->data, iph, hdr_len);
+       return 0;
+}
+
+static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+       return 0;
+}
+
+static struct xfrm_mode xfrm6_transport_mode = {
+       .input = xfrm6_transport_input,
+       .output = xfrm6_transport_output,
+       .owner = THIS_MODULE,
+       .encap = XFRM_MODE_TRANSPORT,
+};
+
+static int __init xfrm6_transport_init(void)
+{
+       return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
+}
+
+static void __exit xfrm6_transport_exit(void)
+{
+       int err;
+
+       err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
+       BUG_ON(err);
+}
+
+module_init(xfrm6_transport_init);
+module_exit(xfrm6_transport_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
new file mode 100644 (file)
index 0000000..8af79be
--- /dev/null
@@ -0,0 +1,121 @@
+/*
+ * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
+ *
+ * Copyright (C) 2002 USAGI/WIDE Project
+ * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stringify.h>
+#include <net/dsfield.h>
+#include <net/dst.h>
+#include <net/inet_ecn.h>
+#include <net/ipv6.h>
+#include <net/xfrm.h>
+
+static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
+{
+       struct ipv6hdr *outer_iph = skb->nh.ipv6h;
+       struct ipv6hdr *inner_iph = skb->h.ipv6h;
+
+       if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
+               IP6_ECN_set_ce(inner_iph);
+}
+
+/* Add encapsulation header.
+ *
+ * The top IP header will be constructed per RFC 2401.  The following fields
+ * in it shall be filled in by x->type->output:
+ *     payload_len
+ *
+ * On exit, skb->h will be set to the start of the encapsulation header to be
+ * filled in by x->type->output and skb->nh will be set to the nextheader field
+ * of the extension header directly preceding the encapsulation header, or in
+ * its absence, that of the top IP header.  The value of skb->data will always
+ * point to the top IP header.
+ */
+static int xfrm6_tunnel_output(struct sk_buff *skb)
+{
+       struct dst_entry *dst = skb->dst;
+       struct xfrm_state *x = dst->xfrm;
+       struct ipv6hdr *iph, *top_iph;
+       int dsfield;
+
+       skb_push(skb, x->props.header_len);
+       iph = skb->nh.ipv6h;
+
+       skb->nh.raw = skb->data;
+       top_iph = skb->nh.ipv6h;
+       skb->nh.raw = &top_iph->nexthdr;
+       skb->h.ipv6h = top_iph + 1;
+
+       top_iph->version = 6;
+       top_iph->priority = iph->priority;
+       top_iph->flow_lbl[0] = iph->flow_lbl[0];
+       top_iph->flow_lbl[1] = iph->flow_lbl[1];
+       top_iph->flow_lbl[2] = iph->flow_lbl[2];
+       dsfield = ipv6_get_dsfield(top_iph);
+       dsfield = INET_ECN_encapsulate(dsfield, dsfield);
+       if (x->props.flags & XFRM_STATE_NOECN)
+               dsfield &= ~INET_ECN_MASK;
+       ipv6_change_dsfield(top_iph, 0, dsfield);
+       top_iph->nexthdr = IPPROTO_IPV6; 
+       top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
+       ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
+       ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
+       return 0;
+}
+
+static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+       int err = -EINVAL;
+
+       if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6)
+               goto out;
+       if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+               goto out;
+
+       if (skb_cloned(skb) &&
+           (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+               goto out;
+
+       if (x->props.flags & XFRM_STATE_DECAP_DSCP)
+               ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
+       if (!(x->props.flags & XFRM_STATE_NOECN))
+               ipip6_ecn_decapsulate(skb);
+       skb->mac.raw = memmove(skb->data - skb->mac_len,
+                              skb->mac.raw, skb->mac_len);
+       skb->nh.raw = skb->data;
+       err = 0;
+
+out:
+       return err;
+}
+
+static struct xfrm_mode xfrm6_tunnel_mode = {
+       .input = xfrm6_tunnel_input,
+       .output = xfrm6_tunnel_output,
+       .owner = THIS_MODULE,
+       .encap = XFRM_MODE_TUNNEL,
+};
+
+static int __init xfrm6_tunnel_init(void)
+{
+       return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
+}
+
+static void __exit xfrm6_tunnel_exit(void)
+{
+       int err;
+
+       err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
+       BUG_ON(err);
+}
+
+module_init(xfrm6_tunnel_init);
+module_exit(xfrm6_tunnel_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
index 8024217..16e8425 100644 (file)
 #include <linux/spinlock.h>
 #include <linux/icmpv6.h>
 #include <linux/netfilter_ipv6.h>
-#include <net/dsfield.h>
-#include <net/inet_ecn.h>
 #include <net/ipv6.h>
 #include <net/xfrm.h>
 
-/* Add encapsulation header.
- *
- * In transport mode, the IP header and mutable extension headers will be moved
- * forward to make space for the encapsulation header.
- *
- * In tunnel mode, the top IP header will be constructed per RFC 2401.
- * The following fields in it shall be filled in by x->type->output:
- *     payload_len
- *
- * On exit, skb->h will be set to the start of the encapsulation header to be
- * filled in by x->type->output and skb->nh will be set to the nextheader field
- * of the extension header directly preceding the encapsulation header, or in
- * its absence, that of the top IP header.  The value of skb->data will always
- * point to the top IP header.
- */
-static void xfrm6_encap(struct sk_buff *skb)
-{
-       struct dst_entry *dst = skb->dst;
-       struct xfrm_state *x = dst->xfrm;
-       struct ipv6hdr *iph, *top_iph;
-       int dsfield;
-
-       skb_push(skb, x->props.header_len);
-       iph = skb->nh.ipv6h;
-
-       if (!x->props.mode) {
-               u8 *prevhdr;
-               int hdr_len;
-
-               hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
-               skb->nh.raw = prevhdr - x->props.header_len;
-               skb->h.raw = skb->data + hdr_len;
-               memmove(skb->data, iph, hdr_len);
-               return;
-       }
-
-       skb->nh.raw = skb->data;
-       top_iph = skb->nh.ipv6h;
-       skb->nh.raw = &top_iph->nexthdr;
-       skb->h.ipv6h = top_iph + 1;
-
-       top_iph->version = 6;
-       top_iph->priority = iph->priority;
-       top_iph->flow_lbl[0] = iph->flow_lbl[0];
-       top_iph->flow_lbl[1] = iph->flow_lbl[1];
-       top_iph->flow_lbl[2] = iph->flow_lbl[2];
-       dsfield = ipv6_get_dsfield(top_iph);
-       dsfield = INET_ECN_encapsulate(dsfield, dsfield);
-       if (x->props.flags & XFRM_STATE_NOECN)
-               dsfield &= ~INET_ECN_MASK;
-       ipv6_change_dsfield(top_iph, 0, dsfield);
-       top_iph->nexthdr = IPPROTO_IPV6; 
-       top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
-       ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
-       ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
-}
-
 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
 {
        int mtu, ret = 0;
@@ -118,7 +59,9 @@ static int xfrm6_output_one(struct sk_buff *skb)
                if (err)
                        goto error;
 
-               xfrm6_encap(skb);
+               err = x->mode->output(skb);
+               if (err)
+                       goto error;
 
                err = x->type->output(x, skb);
                if (err)
index 44b64a5..b893692 100644 (file)
@@ -138,6 +138,89 @@ void xfrm_put_type(struct xfrm_type *type)
        module_put(type->owner);
 }
 
+int xfrm_register_mode(struct xfrm_mode *mode, int family)
+{
+       struct xfrm_policy_afinfo *afinfo;
+       struct xfrm_mode **modemap;
+       int err;
+
+       if (unlikely(mode->encap >= XFRM_MODE_MAX))
+               return -EINVAL;
+
+       afinfo = xfrm_policy_lock_afinfo(family);
+       if (unlikely(afinfo == NULL))
+               return -EAFNOSUPPORT;
+
+       err = -EEXIST;
+       modemap = afinfo->mode_map;
+       if (likely(modemap[mode->encap] == NULL)) {
+               modemap[mode->encap] = mode;
+               err = 0;
+       }
+
+       xfrm_policy_unlock_afinfo(afinfo);
+       return err;
+}
+EXPORT_SYMBOL(xfrm_register_mode);
+
+int xfrm_unregister_mode(struct xfrm_mode *mode, int family)
+{
+       struct xfrm_policy_afinfo *afinfo;
+       struct xfrm_mode **modemap;
+       int err;
+
+       if (unlikely(mode->encap >= XFRM_MODE_MAX))
+               return -EINVAL;
+
+       afinfo = xfrm_policy_lock_afinfo(family);
+       if (unlikely(afinfo == NULL))
+               return -EAFNOSUPPORT;
+
+       err = -ENOENT;
+       modemap = afinfo->mode_map;
+       if (likely(modemap[mode->encap] == mode)) {
+               modemap[mode->encap] = NULL;
+               err = 0;
+       }
+
+       xfrm_policy_unlock_afinfo(afinfo);
+       return err;
+}
+EXPORT_SYMBOL(xfrm_unregister_mode);
+
+struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
+{
+       struct xfrm_policy_afinfo *afinfo;
+       struct xfrm_mode *mode;
+       int modload_attempted = 0;
+
+       if (unlikely(encap >= XFRM_MODE_MAX))
+               return NULL;
+
+retry:
+       afinfo = xfrm_policy_get_afinfo(family);
+       if (unlikely(afinfo == NULL))
+               return NULL;
+
+       mode = afinfo->mode_map[encap];
+       if (unlikely(mode && !try_module_get(mode->owner)))
+               mode = NULL;
+       if (!mode && !modload_attempted) {
+               xfrm_policy_put_afinfo(afinfo);
+               request_module("xfrm-mode-%d-%d", family, encap);
+               modload_attempted = 1;
+               goto retry;
+       }
+
+       xfrm_policy_put_afinfo(afinfo);
+       return mode;
+}
+
+void xfrm_put_mode(struct xfrm_mode *mode)
+{
+       module_put(mode->owner);
+}
+
 static inline unsigned long make_jiffies(long secs)
 {
        if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
index ee62c23..17b29ec 100644 (file)
@@ -77,6 +77,8 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x)
        kfree(x->ealg);
        kfree(x->calg);
        kfree(x->encap);
+       if (x->mode)
+               xfrm_put_mode(x->mode);
        if (x->type) {
                x->type->destructor(x);
                xfrm_put_type(x->type);
@@ -1193,6 +1195,10 @@ int xfrm_init_state(struct xfrm_state *x)
        if (err)
                goto error;
 
+       x->mode = xfrm_get_mode(x->props.mode, family);
+       if (x->mode == NULL)
+               goto error;
+
        x->km.state = XFRM_STATE_VALID;
 
 error: