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-rw-r--r--net/ipv6/ipcomp6.c524
1 files changed, 524 insertions, 0 deletions
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
new file mode 100644
index 000000000000..6cde5310cd76
--- /dev/null
+++ b/net/ipv6/ipcomp6.c
@@ -0,0 +1,524 @@
+/*
+ * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
+ *
+ * Copyright (C)2003 USAGI/WIDE Project
+ *
+ * Author Mitsuru KANDA <mk@linux-ipv6.org>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+/*
+ * [Memo]
+ *
+ * Outbound:
+ * The compression of IP datagram MUST be done before AH/ESP processing,
+ * fragmentation, and the addition of Hop-by-Hop/Routing header.
+ *
+ * Inbound:
+ * The decompression of IP datagram MUST be done after the reassembly,
+ * AH/ESP processing.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/ipcomp.h>
+#include <asm/scatterlist.h>
+#include <asm/semaphore.h>
+#include <linux/crypto.h>
+#include <linux/pfkeyv2.h>
+#include <linux/random.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/rtnetlink.h>
+#include <net/icmp.h>
+#include <net/ipv6.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+
+struct ipcomp6_tfms {
+ struct list_head list;
+ struct crypto_tfm **tfms;
+ int users;
+};
+
+static DECLARE_MUTEX(ipcomp6_resource_sem);
+static void **ipcomp6_scratches;
+static int ipcomp6_scratch_users;
+static LIST_HEAD(ipcomp6_tfms_list);
+
+static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
+{
+ int err = 0;
+ u8 nexthdr = 0;
+ int hdr_len = skb->h.raw - skb->nh.raw;
+ unsigned char *tmp_hdr = NULL;
+ struct ipv6hdr *iph;
+ int plen, dlen;
+ struct ipcomp_data *ipcd = x->data;
+ u8 *start, *scratch;
+ struct crypto_tfm *tfm;
+ int cpu;
+
+ if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
+ skb_linearize(skb, GFP_ATOMIC) != 0) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Remove ipcomp header and decompress original payload */
+ iph = skb->nh.ipv6h;
+ tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
+ if (!tmp_hdr)
+ goto out;
+ memcpy(tmp_hdr, iph, hdr_len);
+ nexthdr = *(u8 *)skb->data;
+ skb_pull(skb, sizeof(struct ipv6_comp_hdr));
+ skb->nh.raw += sizeof(struct ipv6_comp_hdr);
+ memcpy(skb->nh.raw, tmp_hdr, hdr_len);
+ iph = skb->nh.ipv6h;
+ iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
+ skb->h.raw = skb->data;
+
+ /* decompression */
+ plen = skb->len;
+ dlen = IPCOMP_SCRATCH_SIZE;
+ start = skb->data;
+
+ cpu = get_cpu();
+ scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
+ tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+
+ err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
+ if (err) {
+ err = -EINVAL;
+ goto out_put_cpu;
+ }
+
+ if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
+ err = -EINVAL;
+ goto out_put_cpu;
+ }
+
+ err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
+ if (err) {
+ goto out_put_cpu;
+ }
+
+ skb_put(skb, dlen - plen);
+ memcpy(skb->data, scratch, dlen);
+
+ iph = skb->nh.ipv6h;
+ iph->payload_len = htons(skb->len);
+
+out_put_cpu:
+ put_cpu();
+out:
+ if (tmp_hdr)
+ kfree(tmp_hdr);
+ if (err)
+ goto error_out;
+ return nexthdr;
+error_out:
+ return err;
+}
+
+static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+ struct ipv6hdr *top_iph;
+ int hdr_len;
+ struct ipv6_comp_hdr *ipch;
+ struct ipcomp_data *ipcd = x->data;
+ int plen, dlen;
+ u8 *start, *scratch;
+ struct crypto_tfm *tfm;
+ int cpu;
+
+ hdr_len = skb->h.raw - skb->data;
+
+ /* check whether datagram len is larger than threshold */
+ if ((skb->len - hdr_len) < ipcd->threshold) {
+ goto out_ok;
+ }
+
+ if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
+ skb_linearize(skb, GFP_ATOMIC) != 0) {
+ goto out_ok;
+ }
+
+ /* compression */
+ plen = skb->len - hdr_len;
+ dlen = IPCOMP_SCRATCH_SIZE;
+ start = skb->h.raw;
+
+ cpu = get_cpu();
+ scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
+ tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+
+ err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
+ if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
+ put_cpu();
+ goto out_ok;
+ }
+ memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
+ put_cpu();
+ pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
+
+ /* insert ipcomp header and replace datagram */
+ top_iph = (struct ipv6hdr *)skb->data;
+
+ top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
+
+ ipch = (struct ipv6_comp_hdr *)start;
+ ipch->nexthdr = *skb->nh.raw;
+ ipch->flags = 0;
+ ipch->cpi = htons((u16 )ntohl(x->id.spi));
+ *skb->nh.raw = IPPROTO_COMP;
+
+out_ok:
+ return 0;
+}
+
+static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+ int type, int code, int offset, __u32 info)
+{
+ u32 spi;
+ struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
+ struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
+ struct xfrm_state *x;
+
+ if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
+ return;
+
+ spi = ntohl(ntohs(ipcomph->cpi));
+ x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
+ if (!x)
+ return;
+
+ printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/"
+ "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+ spi, NIP6(iph->daddr));
+ xfrm_state_put(x);
+}
+
+static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
+{
+ struct xfrm_state *t = NULL;
+
+ t = xfrm_state_alloc();
+ if (!t)
+ goto out;
+
+ t->id.proto = IPPROTO_IPV6;
+ t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
+ 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 = 1;
+ memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
+
+ t->type = xfrm_get_type(IPPROTO_IPV6, t->props.family);
+ if (t->type == NULL)
+ goto error;
+
+ if (t->type->init_state(t, NULL))
+ goto error;
+
+ t->km.state = XFRM_STATE_VALID;
+ atomic_set(&t->tunnel_users, 1);
+
+out:
+ return t;
+
+error:
+ xfrm_state_put(t);
+ goto out;
+}
+
+static int ipcomp6_tunnel_attach(struct xfrm_state *x)
+{
+ int err = 0;
+ struct xfrm_state *t = NULL;
+ u32 spi;
+
+ spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
+ if (spi)
+ t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
+ spi, IPPROTO_IPV6, AF_INET6);
+ if (!t) {
+ t = ipcomp6_tunnel_create(x);
+ if (!t) {
+ err = -EINVAL;
+ goto out;
+ }
+ xfrm_state_insert(t);
+ xfrm_state_hold(t);
+ }
+ x->tunnel = t;
+ atomic_inc(&t->tunnel_users);
+
+out:
+ return err;
+}
+
+static void ipcomp6_free_scratches(void)
+{
+ int i;
+ void **scratches;
+
+ if (--ipcomp6_scratch_users)
+ return;
+
+ scratches = ipcomp6_scratches;
+ if (!scratches)
+ return;
+
+ for_each_cpu(i) {
+ void *scratch = *per_cpu_ptr(scratches, i);
+ if (scratch)
+ vfree(scratch);
+ }
+
+ free_percpu(scratches);
+}
+
+static void **ipcomp6_alloc_scratches(void)
+{
+ int i;
+ void **scratches;
+
+ if (ipcomp6_scratch_users++)
+ return ipcomp6_scratches;
+
+ scratches = alloc_percpu(void *);
+ if (!scratches)
+ return NULL;
+
+ ipcomp6_scratches = scratches;
+
+ for_each_cpu(i) {
+ void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
+ if (!scratch)
+ return NULL;
+ *per_cpu_ptr(scratches, i) = scratch;
+ }
+
+ return scratches;
+}
+
+static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
+{
+ struct ipcomp6_tfms *pos;
+ int cpu;
+
+ list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
+ if (pos->tfms == tfms)
+ break;
+ }
+
+ BUG_TRAP(pos);
+
+ if (--pos->users)
+ return;
+
+ list_del(&pos->list);
+ kfree(pos);
+
+ if (!tfms)
+ return;
+
+ for_each_cpu(cpu) {
+ struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
+ if (tfm)
+ crypto_free_tfm(tfm);
+ }
+ free_percpu(tfms);
+}
+
+static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
+{
+ struct ipcomp6_tfms *pos;
+ struct crypto_tfm **tfms;
+ int cpu;
+
+ /* This can be any valid CPU ID so we don't need locking. */
+ cpu = smp_processor_id();
+
+ list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
+ struct crypto_tfm *tfm;
+
+ tfms = pos->tfms;
+ tfm = *per_cpu_ptr(tfms, cpu);
+
+ if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
+ pos->users++;
+ return tfms;
+ }
+ }
+
+ pos = kmalloc(sizeof(*pos), GFP_KERNEL);
+ if (!pos)
+ return NULL;
+
+ pos->users = 1;
+ INIT_LIST_HEAD(&pos->list);
+ list_add(&pos->list, &ipcomp6_tfms_list);
+
+ pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
+ if (!tfms)
+ goto error;
+
+ for_each_cpu(cpu) {
+ struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
+ if (!tfm)
+ goto error;
+ *per_cpu_ptr(tfms, cpu) = tfm;
+ }
+
+ return tfms;
+
+error:
+ ipcomp6_free_tfms(tfms);
+ return NULL;
+}
+
+static void ipcomp6_free_data(struct ipcomp_data *ipcd)
+{
+ if (ipcd->tfms)
+ ipcomp6_free_tfms(ipcd->tfms);
+ ipcomp6_free_scratches();
+}
+
+static void ipcomp6_destroy(struct xfrm_state *x)
+{
+ struct ipcomp_data *ipcd = x->data;
+ if (!ipcd)
+ return;
+ xfrm_state_delete_tunnel(x);
+ down(&ipcomp6_resource_sem);
+ ipcomp6_free_data(ipcd);
+ up(&ipcomp6_resource_sem);
+ kfree(ipcd);
+
+ xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
+}
+
+static int ipcomp6_init_state(struct xfrm_state *x, void *args)
+{
+ int err;
+ struct ipcomp_data *ipcd;
+ struct xfrm_algo_desc *calg_desc;
+
+ err = -EINVAL;
+ if (!x->calg)
+ goto out;
+
+ if (x->encap)
+ goto out;
+
+ err = -ENOMEM;
+ ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
+ if (!ipcd)
+ goto out;
+
+ memset(ipcd, 0, sizeof(*ipcd));
+ x->props.header_len = 0;
+ if (x->props.mode)
+ x->props.header_len += sizeof(struct ipv6hdr);
+
+ down(&ipcomp6_resource_sem);
+ if (!ipcomp6_alloc_scratches())
+ goto error;
+
+ ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
+ if (!ipcd->tfms)
+ goto error;
+ up(&ipcomp6_resource_sem);
+
+ if (x->props.mode) {
+ err = ipcomp6_tunnel_attach(x);
+ if (err)
+ goto error_tunnel;
+ }
+
+ calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
+ BUG_ON(!calg_desc);
+ ipcd->threshold = calg_desc->uinfo.comp.threshold;
+ x->data = ipcd;
+ err = 0;
+out:
+ return err;
+error_tunnel:
+ down(&ipcomp6_resource_sem);
+error:
+ ipcomp6_free_data(ipcd);
+ up(&ipcomp6_resource_sem);
+ kfree(ipcd);
+
+ goto out;
+}
+
+static struct xfrm_type ipcomp6_type =
+{
+ .description = "IPCOMP6",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_COMP,
+ .init_state = ipcomp6_init_state,
+ .destructor = ipcomp6_destroy,
+ .input = ipcomp6_input,
+ .output = ipcomp6_output,
+};
+
+static struct inet6_protocol ipcomp6_protocol =
+{
+ .handler = xfrm6_rcv,
+ .err_handler = ipcomp6_err,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+static int __init ipcomp6_init(void)
+{
+ if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
+ printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
+ return -EAGAIN;
+ }
+ if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
+ printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
+ xfrm_unregister_type(&ipcomp6_type, AF_INET6);
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+static void __exit ipcomp6_fini(void)
+{
+ if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
+ printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
+ if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
+ printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
+}
+
+module_init(ipcomp6_init);
+module_exit(ipcomp6_fini);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
+MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
+
+
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