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-rw-r--r--net/ipv4/ipcomp.c524
1 files changed, 524 insertions, 0 deletions
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
new file mode 100644
index 0000000..1a23c52
--- /dev/null
+++ b/net/ipv4/ipcomp.c
@@ -0,0 +1,524 @@
+/*
+ * IP Payload Compression Protocol (IPComp) - RFC3173.
+ *
+ * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
+ *
+ * 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.
+ *
+ * Todo:
+ * - Tunable compression parameters.
+ * - Compression stats.
+ * - Adaptive compression.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <asm/scatterlist.h>
+#include <asm/semaphore.h>
+#include <linux/crypto.h>
+#include <linux/pfkeyv2.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/rtnetlink.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/icmp.h>
+#include <net/ipcomp.h>
+
+struct ipcomp_tfms {
+ struct list_head list;
+ struct crypto_tfm **tfms;
+ int users;
+};
+
+static DECLARE_MUTEX(ipcomp_resource_sem);
+static void **ipcomp_scratches;
+static int ipcomp_scratch_users;
+static LIST_HEAD(ipcomp_tfms_list);
+
+static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err, plen, dlen;
+ struct iphdr *iph;
+ struct ipcomp_data *ipcd = x->data;
+ u8 *start, *scratch;
+ struct crypto_tfm *tfm;
+ int cpu;
+
+ plen = skb->len;
+ dlen = IPCOMP_SCRATCH_SIZE;
+ start = skb->data;
+
+ cpu = get_cpu();
+ scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
+ tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+
+ err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
+ if (err)
+ goto out;
+
+ if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
+ if (err)
+ goto out;
+
+ skb_put(skb, dlen - plen);
+ memcpy(skb->data, scratch, dlen);
+ iph = skb->nh.iph;
+ iph->tot_len = htons(dlen + iph->ihl * 4);
+out:
+ put_cpu();
+ return err;
+}
+
+static int ipcomp_input(struct xfrm_state *x,
+ struct xfrm_decap_state *decap, struct sk_buff *skb)
+{
+ u8 nexthdr;
+ int err = 0;
+ struct iphdr *iph;
+ union {
+ struct iphdr iph;
+ char buf[60];
+ } tmp_iph;
+
+
+ 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.iph;
+ memcpy(&tmp_iph, iph, iph->ihl * 4);
+ nexthdr = *(u8 *)skb->data;
+ skb_pull(skb, sizeof(struct ip_comp_hdr));
+ skb->nh.raw += sizeof(struct ip_comp_hdr);
+ memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
+ iph = skb->nh.iph;
+ iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
+ iph->protocol = nexthdr;
+ skb->h.raw = skb->data;
+ err = ipcomp_decompress(x, skb);
+
+out:
+ return err;
+}
+
+static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err, plen, dlen, ihlen;
+ struct iphdr *iph = skb->nh.iph;
+ struct ipcomp_data *ipcd = x->data;
+ u8 *start, *scratch;
+ struct crypto_tfm *tfm;
+ int cpu;
+
+ ihlen = iph->ihl * 4;
+ plen = skb->len - ihlen;
+ dlen = IPCOMP_SCRATCH_SIZE;
+ start = skb->data + ihlen;
+
+ cpu = get_cpu();
+ scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
+ tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+
+ err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
+ if (err)
+ goto out;
+
+ if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
+ err = -EMSGSIZE;
+ goto out;
+ }
+
+ memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
+ put_cpu();
+
+ pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
+ return 0;
+
+out:
+ put_cpu();
+ return err;
+}
+
+static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+ struct iphdr *iph;
+ struct ip_comp_hdr *ipch;
+ struct ipcomp_data *ipcd = x->data;
+ int hdr_len = 0;
+
+ iph = skb->nh.iph;
+ iph->tot_len = htons(skb->len);
+ hdr_len = iph->ihl * 4;
+ if ((skb->len - hdr_len) < ipcd->threshold) {
+ /* Don't bother compressing */
+ goto out_ok;
+ }
+
+ if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
+ skb_linearize(skb, GFP_ATOMIC) != 0) {
+ goto out_ok;
+ }
+
+ err = ipcomp_compress(x, skb);
+ iph = skb->nh.iph;
+
+ if (err) {
+ goto out_ok;
+ }
+
+ /* Install ipcomp header, convert into ipcomp datagram. */
+ iph->tot_len = htons(skb->len);
+ ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
+ ipch->nexthdr = iph->protocol;
+ ipch->flags = 0;
+ ipch->cpi = htons((u16 )ntohl(x->id.spi));
+ iph->protocol = IPPROTO_COMP;
+ ip_send_check(iph);
+ return 0;
+
+out_ok:
+ if (x->props.mode)
+ ip_send_check(iph);
+ return 0;
+}
+
+static void ipcomp4_err(struct sk_buff *skb, u32 info)
+{
+ u32 spi;
+ struct iphdr *iph = (struct iphdr *)skb->data;
+ struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
+ struct xfrm_state *x;
+
+ if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
+ skb->h.icmph->code != ICMP_FRAG_NEEDED)
+ return;
+
+ spi = ntohl(ntohs(ipch->cpi));
+ x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
+ spi, IPPROTO_COMP, AF_INET);
+ if (!x)
+ return;
+ NETDEBUG(printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
+ spi, NIPQUAD(iph->daddr)));
+ xfrm_state_put(x);
+}
+
+/* We always hold one tunnel user reference to indicate a tunnel */
+static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
+{
+ struct xfrm_state *t;
+
+ t = xfrm_state_alloc();
+ if (t == NULL)
+ goto out;
+
+ t->id.proto = IPPROTO_IPIP;
+ t->id.spi = x->props.saddr.a4;
+ t->id.daddr.a4 = x->id.daddr.a4;
+ memcpy(&t->sel, &x->sel, sizeof(t->sel));
+ t->props.family = AF_INET;
+ t->props.mode = 1;
+ t->props.saddr.a4 = x->props.saddr.a4;
+ t->props.flags = x->props.flags;
+
+ t->type = xfrm_get_type(IPPROTO_IPIP, 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:
+ t->km.state = XFRM_STATE_DEAD;
+ xfrm_state_put(t);
+ t = NULL;
+ goto out;
+}
+
+/*
+ * Must be protected by xfrm_cfg_sem. State and tunnel user references are
+ * always incremented on success.
+ */
+static int ipcomp_tunnel_attach(struct xfrm_state *x)
+{
+ int err = 0;
+ struct xfrm_state *t;
+
+ t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
+ x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
+ if (!t) {
+ t = ipcomp_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 ipcomp_free_scratches(void)
+{
+ int i;
+ void **scratches;
+
+ if (--ipcomp_scratch_users)
+ return;
+
+ scratches = ipcomp_scratches;
+ if (!scratches)
+ return;
+
+ for_each_cpu(i) {
+ void *scratch = *per_cpu_ptr(scratches, i);
+ if (scratch)
+ vfree(scratch);
+ }
+
+ free_percpu(scratches);
+}
+
+static void **ipcomp_alloc_scratches(void)
+{
+ int i;
+ void **scratches;
+
+ if (ipcomp_scratch_users++)
+ return ipcomp_scratches;
+
+ scratches = alloc_percpu(void *);
+ if (!scratches)
+ return NULL;
+
+ ipcomp_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 ipcomp_free_tfms(struct crypto_tfm **tfms)
+{
+ struct ipcomp_tfms *pos;
+ int cpu;
+
+ list_for_each_entry(pos, &ipcomp_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 **ipcomp_alloc_tfms(const char *alg_name)
+{
+ struct ipcomp_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, &ipcomp_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, &ipcomp_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:
+ ipcomp_free_tfms(tfms);
+ return NULL;
+}
+
+static void ipcomp_free_data(struct ipcomp_data *ipcd)
+{
+ if (ipcd->tfms)
+ ipcomp_free_tfms(ipcd->tfms);
+ ipcomp_free_scratches();
+}
+
+static void ipcomp_destroy(struct xfrm_state *x)
+{
+ struct ipcomp_data *ipcd = x->data;
+ if (!ipcd)
+ return;
+ xfrm_state_delete_tunnel(x);
+ down(&ipcomp_resource_sem);
+ ipcomp_free_data(ipcd);
+ up(&ipcomp_resource_sem);
+ kfree(ipcd);
+}
+
+static int ipcomp_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 iphdr);
+
+ down(&ipcomp_resource_sem);
+ if (!ipcomp_alloc_scratches())
+ goto error;
+
+ ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
+ if (!ipcd->tfms)
+ goto error;
+ up(&ipcomp_resource_sem);
+
+ if (x->props.mode) {
+ err = ipcomp_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(&ipcomp_resource_sem);
+error:
+ ipcomp_free_data(ipcd);
+ up(&ipcomp_resource_sem);
+ kfree(ipcd);
+ goto out;
+}
+
+static struct xfrm_type ipcomp_type = {
+ .description = "IPCOMP4",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_COMP,
+ .init_state = ipcomp_init_state,
+ .destructor = ipcomp_destroy,
+ .input = ipcomp_input,
+ .output = ipcomp_output
+};
+
+static struct net_protocol ipcomp4_protocol = {
+ .handler = xfrm4_rcv,
+ .err_handler = ipcomp4_err,
+ .no_policy = 1,
+};
+
+static int __init ipcomp4_init(void)
+{
+ if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
+ printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
+ return -EAGAIN;
+ }
+ if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
+ printk(KERN_INFO "ipcomp init: can't add protocol\n");
+ xfrm_unregister_type(&ipcomp_type, AF_INET);
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+static void __exit ipcomp4_fini(void)
+{
+ if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
+ printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
+ if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
+ printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
+}
+
+module_init(ipcomp4_init);
+module_exit(ipcomp4_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
+MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
+
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