[XFRM]: BEET mode

This patch introduces the BEET mode (Bound End-to-End Tunnel) with as
specified by the ietf draft at the following link:

http://www.ietf.org/internet-drafts/draft-nikander-esp-beet-mode-06.txt

The patch provides only single family support (i.e. inner family =
outer family).

Signed-off-by: Diego Beltrami <diego.beltrami@gmail.com>
Signed-off-by: Miika Komu     <miika@iki.fi>
Signed-off-by: Herbert Xu     <herbert@gondor.apana.org.au>
Signed-off-by: Abhinav Pathak <abhinav.pathak@hiit.fi>
Signed-off-by: Jeff Ahrenholz <ahrenholz@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

14 files changed, 309 insertions, 11 deletions

diff --git a/include/linux/in.h b/include/linux/in.h
index d79fc75fa7c2..2619859f6e1b 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -40,6 +40,7 @@ enum {
 
   IPPROTO_ESP = 50,            /* Encapsulation Security Payload protocol */
   IPPROTO_AH = 51,             /* Authentication Header protocol       */
+  IPPROTO_BEETPH = 94,         /* IP option pseudo header for BEET */
   IPPROTO_PIM    = 103,         /* Protocol Independent Multicast       */
 
   IPPROTO_COMP   = 108,                /* Compression Header protocol */
diff --git a/include/linux/ip.h b/include/linux/ip.h
index 6b25d36fc54c..ecee9bb27d0e 100644
--- a/include/linux/ip.h
+++ b/include/linux/ip.h
@@ -80,6 +80,8 @@
 #define IPOPT_TS_TSANDADDR      1               /* timestamps and addresses */
 #define IPOPT_TS_PRESPEC        3               /* specified modules only */
 
+#define IPV4_BEET_PHMAXLEN 8
+
 struct iphdr {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
         __u8    ihl:4,
@@ -123,4 +125,11 @@ struct ip_comp_hdr {
         __be16 cpi;
 };
 
+struct ip_beet_phdr {
+        __u8 nexthdr;
+        __u8 hdrlen;
+        __u8 padlen;
+        __u8 reserved;
+};
+
 #endif  /* _LINUX_IP_H */
diff --git a/include/linux/ipsec.h b/include/linux/ipsec.h
index d3c527616b5e..d17a6302a0e9 100644
--- a/include/linux/ipsec.h
+++ b/include/linux/ipsec.h
@@ -12,7 +12,8 @@
 enum {
         IPSEC_MODE_ANY          = 0,    /* We do not support this for SA */
         IPSEC_MODE_TRANSPORT    = 1,
-        IPSEC_MODE_TUNNEL       = 2
+        IPSEC_MODE_TUNNEL       = 2,
+        IPSEC_MODE_BEET         = 3
 };
 
 enum {
diff --git a/include/linux/xfrm.h b/include/linux/xfrm.h
index 430afd058269..8ae7f744917b 100644
--- a/include/linux/xfrm.h
+++ b/include/linux/xfrm.h
@@ -129,7 +129,8 @@ enum
 #define XFRM_MODE_TUNNEL 1
 #define XFRM_MODE_ROUTEOPTIMIZATION 2
 #define XFRM_MODE_IN_TRIGGER 3
-#define XFRM_MODE_MAX 4
+#define XFRM_MODE_BEET 4
+#define XFRM_MODE_MAX 5
 
 /* Netlink configuration messages.  */
 enum {
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index d172a9804448..5572071af735 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -434,6 +434,15 @@ config INET_XFRM_MODE_TUNNEL
 
           If unsure, say Y.
 
+config INET_XFRM_MODE_BEET
+        tristate "IP: IPsec BEET mode"
+        default y
+        select XFRM
+        ---help---
+          Support for IPsec BEET mode.
+
+          If unsure, say Y.
+
 config INET_DIAG
         tristate "INET: socket monitoring interface"
         default y
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index f66049e28aeb..15645c51520c 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_INET_AH) += ah4.o
 obj-$(CONFIG_INET_ESP) += esp4.o
 obj-$(CONFIG_INET_IPCOMP) += ipcomp.o
 obj-$(CONFIG_INET_XFRM_TUNNEL) += xfrm4_tunnel.o
+obj-$(CONFIG_INET_XFRM_MODE_BEET) += xfrm4_mode_beet.o
 obj-$(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
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 13b29360d102..b5c205b57669 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -253,7 +253,8 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
                  *    as per draft-ietf-ipsec-udp-encaps-06,
                  *    section 3.1.2
                  */
-                if (x->props.mode == XFRM_MODE_TRANSPORT)
+                if (x->props.mode == XFRM_MODE_TRANSPORT ||
+                    x->props.mode == XFRM_MODE_BEET)
                         skb->ip_summed = CHECKSUM_UNNECESSARY;
         }
 
@@ -271,17 +272,28 @@ static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
 {
         struct esp_data *esp = x->data;
         u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
-
-        if (x->props.mode == XFRM_MODE_TUNNEL) {
-                mtu = ALIGN(mtu + 2, blksize);
-        } else {
-                /* The worst case. */
+        int enclen = 0;
+
+        switch (x->props.mode) {
+        case XFRM_MODE_TUNNEL:
+                mtu = ALIGN(mtu +2, blksize);
+                break;
+        default:
+        case XFRM_MODE_TRANSPORT:
+                /* The worst case */
                 mtu = ALIGN(mtu + 2, 4) + blksize - 4;
+                break;
+        case XFRM_MODE_BEET:
+                /* The worst case. */
+                enclen = IPV4_BEET_PHMAXLEN;
+                mtu = ALIGN(mtu + enclen + 2, blksize);
+                break;
         }
+
         if (esp->conf.padlen)
                 mtu = ALIGN(mtu, esp->conf.padlen);
 
-        return mtu + x->props.header_len + esp->auth.icv_trunc_len;
+        return mtu + x->props.header_len + esp->auth.icv_trunc_len - enclen;
 }
 
 static void esp4_err(struct sk_buff *skb, u32 info)
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index 2017d36024d4..3839b706142e 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -206,6 +206,7 @@ static void ipcomp4_err(struct sk_buff *skb, u32 info)
 static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
 {
         struct xfrm_state *t;
+        u8 mode = XFRM_MODE_TUNNEL;
         
         t = xfrm_state_alloc();
         if (t == NULL)
@@ -216,7 +217,9 @@ static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
         t->id.daddr.a4 = x->id.daddr.a4;
         memcpy(&t->sel, &x->sel, sizeof(t->sel));
         t->props.family = AF_INET;
-        t->props.mode = XFRM_MODE_TUNNEL;
+        if (x->props.mode == XFRM_MODE_BEET)
+                mode = x->props.mode;
+        t->props.mode = mode;
         t->props.saddr.a4 = x->props.saddr.a4;
         t->props.flags = x->props.flags;
 
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
new file mode 100644
index 000000000000..89cf59ea7bbe
--- /dev/null
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -0,0 +1,139 @@
+/*
+ * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
+ *
+ * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
+ *                    Miika Komu     <miika@iki.fi>
+ *                    Herbert Xu     <herbert@gondor.apana.org.au>
+ *                    Abhinav Pathak <abhinav.pathak@hiit.fi>
+ *                    Jeff Ahrenholz <ahrenholz@gmail.com>
+ */
+
+#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 top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
+ * 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_beet_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+        struct iphdr *iph, *top_iph = NULL;
+        int hdrlen, optlen;
+
+        iph = skb->nh.iph;
+        skb->h.ipiph = iph;
+
+        hdrlen = 0;
+        optlen = iph->ihl * 4 - sizeof(*iph);
+        if (unlikely(optlen))
+                hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
+
+        skb->nh.raw = skb_push(skb, x->props.header_len + hdrlen);
+        top_iph = skb->nh.iph;
+        hdrlen = iph->ihl * 4 - optlen;
+        skb->h.raw += hdrlen;
+
+        memmove(top_iph, iph, hdrlen);
+        if (unlikely(optlen)) {
+                struct ip_beet_phdr *ph;
+
+                BUG_ON(optlen < 0);
+
+                ph = (struct ip_beet_phdr *)skb->h.raw;
+                ph->padlen = 4 - (optlen & 4);
+                ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8;
+                ph->nexthdr = top_iph->protocol;
+
+                top_iph->protocol = IPPROTO_BEETPH;
+                top_iph->ihl = sizeof(struct iphdr) / 4;
+        }
+
+        top_iph->saddr = x->props.saddr.a4;
+        top_iph->daddr = x->id.daddr.a4;
+
+        return 0;
+}
+
+static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+        struct iphdr *iph = skb->nh.iph;
+        int phlen = 0;
+        int optlen = 0;
+        __u8 ph_nexthdr = 0, protocol = 0;
+        int err = -EINVAL;
+
+        protocol = iph->protocol;
+
+        if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
+                struct ip_beet_phdr *ph = (struct ip_beet_phdr*)(iph + 1);
+
+                if (!pskb_may_pull(skb, sizeof(*ph)))
+                        goto out;
+
+                phlen = ph->hdrlen * 8;
+                optlen = phlen - ph->padlen - sizeof(*ph);
+                if (optlen < 0 || optlen & 3 || optlen > 250)
+                        goto out;
+
+                if (!pskb_may_pull(skb, phlen))
+                        goto out;
+
+                ph_nexthdr = ph->nexthdr;
+        }
+
+        skb_push(skb, sizeof(*iph) - phlen + optlen);
+        memmove(skb->data, skb->nh.raw, sizeof(*iph));
+        skb->nh.raw = skb->data;
+
+        iph = skb->nh.iph;
+        iph->ihl = (sizeof(*iph) + optlen) / 4;
+        iph->tot_len = htons(skb->len);
+        iph->daddr = x->sel.daddr.a4;
+        iph->saddr = x->sel.saddr.a4;
+        if (ph_nexthdr)
+                iph->protocol = ph_nexthdr;
+        else
+                iph->protocol = protocol;
+        iph->check = 0;
+        iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
+        err = 0;
+out:
+        return err;
+}
+
+static struct xfrm_mode xfrm4_beet_mode = {
+        .input = xfrm4_beet_input,
+        .output = xfrm4_beet_output,
+        .owner = THIS_MODULE,
+        .encap = XFRM_MODE_BEET,
+};
+
+static int __init xfrm4_beet_init(void)
+{
+        return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
+}
+
+static void __exit xfrm4_beet_exit(void)
+{
+        int err;
+
+        err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
+        BUG_ON(err);
+}
+
+module_init(xfrm4_beet_init);
+module_exit(xfrm4_beet_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);
diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index a2d211da2aba..a460e8132b4d 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -136,6 +136,16 @@ config INET6_XFRM_MODE_TUNNEL
 
           If unsure, say Y.
 
+config INET6_XFRM_MODE_BEET
+        tristate "IPv6: IPsec BEET mode"
+        depends on IPV6
+        default IPV6
+        select XFRM
+        ---help---
+          Support for IPsec BEET mode.
+
+          If unsure, say Y.
+
 config INET6_XFRM_MODE_ROUTEOPTIMIZATION
         tristate "IPv6: MIPv6 route optimization mode (EXPERIMENTAL)"
         depends on IPV6 && EXPERIMENTAL
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 0213c6612b58..87274e47fe32 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -26,6 +26,7 @@ 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_INET6_XFRM_MODE_ROUTEOPTIMIZATION) += xfrm6_mode_ro.o
+obj-$(CONFIG_INET6_XFRM_MODE_BEET) += xfrm6_mode_beet.o
 obj-$(CONFIG_NETFILTER) += netfilter/
 
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index a2860e35efd7..71f59f18ede8 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -199,6 +199,7 @@ static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
 {
         struct xfrm_state *t = NULL;
+        u8 mode = XFRM_MODE_TUNNEL;
 
         t = xfrm_state_alloc();
         if (!t)
@@ -212,7 +213,9 @@ static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
         memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
         memcpy(&t->sel, &x->sel, sizeof(t->sel));
         t->props.family = AF_INET6;
-        t->props.mode = XFRM_MODE_TUNNEL;
+        if (x->props.mode == XFRM_MODE_BEET)
+                mode = x->props.mode;
+        t->props.mode = mode;
         memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
 
         if (xfrm_init_state(t))
diff --git a/net/ipv6/xfrm6_mode_beet.c b/net/ipv6/xfrm6_mode_beet.c
new file mode 100644
index 000000000000..edcfffa9e87b
--- /dev/null
+++ b/net/ipv6/xfrm6_mode_beet.c
@@ -0,0 +1,107 @@
+/*
+ * xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
+ *
+ * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
+ *                    Miika Komu     <miika@iki.fi>
+ *                    Herbert Xu     <herbert@gondor.apana.org.au>
+ *                    Abhinav Pathak <abhinav.pathak@hiit.fi>
+ *                    Jeff Ahrenholz <ahrenholz@gmail.com>
+ */
+
+#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>
+
+/* Add encapsulation header.
+ *
+ * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
+ * 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_beet_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+        struct ipv6hdr *iph, *top_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);
+
+        skb->nh.raw = skb->data;
+        top_iph = skb->nh.ipv6h;
+        skb->nh.raw = &top_iph->nexthdr;
+        skb->h.ipv6h = top_iph + 1;
+
+        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_beet_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+        struct ipv6hdr *ip6h;
+        int size = sizeof(struct ipv6hdr);
+        int err = -EINVAL;
+
+        if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+                goto out;
+
+        skb_push(skb, size);
+        memmove(skb->data, skb->nh.raw, size);
+        skb->nh.raw = skb->data;
+
+        skb->mac.raw = memmove(skb->data - skb->mac_len,
+                               skb->mac.raw, skb->mac_len);
+
+        ip6h = skb->nh.ipv6h;
+        ip6h->payload_len = htons(skb->len - size);
+        ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
+        ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
+        err = 0;
+out:
+        return err;
+}
+
+static struct xfrm_mode xfrm6_beet_mode = {
+        .input = xfrm6_beet_input,
+        .output = xfrm6_beet_output,
+        .owner = THIS_MODULE,
+        .encap = XFRM_MODE_BEET,
+};
+
+static int __init xfrm6_beet_init(void)
+{
+        return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
+}
+
+static void __exit xfrm6_beet_exit(void)
+{
+        int err;
+
+        err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
+        BUG_ON(err);
+}
+
+module_init(xfrm6_beet_init);
+module_exit(xfrm6_beet_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index c59a78d2923a..d54b3a70d5df 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -211,6 +211,7 @@ static int verify_newsa_info(struct xfrm_usersa_info *p,
         case XFRM_MODE_TRANSPORT:
         case XFRM_MODE_TUNNEL:
         case XFRM_MODE_ROUTEOPTIMIZATION:
+        case XFRM_MODE_BEET:
                 break;
 
         default: