--- /dev/null
+/*
+ * IP Payload Compression Protocol (IPComp) - RFC3173.
+ *
+ * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.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/crypto.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/vmalloc.h>
+#include <net/ip.h>
+#include <net/ipcomp.h>
+#include <net/xfrm.h>
+
+struct ipcomp_tfms {
+ struct list_head list;
+ struct crypto_comp * __percpu *tfms;
+ int users;
+};
+
+static DEFINE_MUTEX(ipcomp_resource_mutex);
+static void * __percpu *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)
+{
+ struct ipcomp_data *ipcd = x->data;
+ const int plen = skb->len;
+ int dlen = IPCOMP_SCRATCH_SIZE;
+ const u8 *start = skb->data;
+ const int cpu = get_cpu();
+ u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
+ struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+ int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
+ int len;
+
+ if (err)
+ goto out;
+
+ if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ len = dlen - plen;
+ if (len > skb_tailroom(skb))
+ len = skb_tailroom(skb);
+
+ __skb_put(skb, len);
+
+ len += plen;
+ skb_copy_to_linear_data(skb, scratch, len);
+
+ while ((scratch += len, dlen -= len) > 0) {
+ skb_frag_t *frag;
+ struct page *page;
+
+ err = -EMSGSIZE;
+ if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
+ goto out;
+
+ frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
+ page = alloc_page(GFP_ATOMIC);
+
+ err = -ENOMEM;
+ if (!page)
+ goto out;
+
+ __skb_frag_set_page(frag, page);
+
+ len = PAGE_SIZE;
+ if (dlen < len)
+ len = dlen;
+
+ frag->page_offset = 0;
+ skb_frag_size_set(frag, len);
+ memcpy(skb_frag_address(frag), scratch, len);
+
+ skb->truesize += len;
+ skb->data_len += len;
+ skb->len += len;
+
+ skb_shinfo(skb)->nr_frags++;
+ }
+
+ err = 0;
+
+out:
+ put_cpu();
+ return err;
+}
+
+int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int nexthdr;
+ int err = -ENOMEM;
+ struct ip_comp_hdr *ipch;
+
+ if (skb_linearize_cow(skb))
+ goto out;
+
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Remove ipcomp header and decompress original payload */
+ ipch = (void *)skb->data;
+ nexthdr = ipch->nexthdr;
+
+ skb->transport_header = skb->network_header + sizeof(*ipch);
+ __skb_pull(skb, sizeof(*ipch));
+ err = ipcomp_decompress(x, skb);
+ if (err)
+ goto out;
+
+ err = nexthdr;
+
+out:
+ return err;
+}
+EXPORT_SYMBOL_GPL(ipcomp_input);
+
+static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct ipcomp_data *ipcd = x->data;
+ const int plen = skb->len;
+ int dlen = IPCOMP_SCRATCH_SIZE;
+ u8 *start = skb->data;
+ struct crypto_comp *tfm;
+ u8 *scratch;
+ int err;
+
+ local_bh_disable();
+ scratch = *this_cpu_ptr(ipcomp_scratches);
+ tfm = *this_cpu_ptr(ipcd->tfms);
+ 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);
+ local_bh_enable();
+
+ pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
+ return 0;
+
+out:
+ local_bh_enable();
+ return err;
+}
+
+int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+ struct ip_comp_hdr *ipch;
+ struct ipcomp_data *ipcd = x->data;
+
+ if (skb->len < ipcd->threshold) {
+ /* Don't bother compressing */
+ goto out_ok;
+ }
+
+ if (skb_linearize_cow(skb))
+ goto out_ok;
+
+ err = ipcomp_compress(x, skb);
+
+ if (err) {
+ goto out_ok;
+ }
+
+ /* Install ipcomp header, convert into ipcomp datagram. */
+ ipch = ip_comp_hdr(skb);
+ ipch->nexthdr = *skb_mac_header(skb);
+ ipch->flags = 0;
+ ipch->cpi = htons((u16 )ntohl(x->id.spi));
+ *skb_mac_header(skb) = IPPROTO_COMP;
+out_ok:
+ skb_push(skb, -skb_network_offset(skb));
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ipcomp_output);
+
+static void ipcomp_free_scratches(void)
+{
+ int i;
+ void * __percpu *scratches;
+
+ if (--ipcomp_scratch_users)
+ return;
+
+ scratches = ipcomp_scratches;
+ if (!scratches)
+ return;
+
+ for_each_possible_cpu(i)
+ vfree(*per_cpu_ptr(scratches, i));
+
+ free_percpu(scratches);
+}
+
+static void * __percpu *ipcomp_alloc_scratches(void)
+{
+ void * __percpu *scratches;
+ int i;
+
+ if (ipcomp_scratch_users++)
+ return ipcomp_scratches;
+
+ scratches = alloc_percpu(void *);
+ if (!scratches)
+ return NULL;
+
+ ipcomp_scratches = scratches;
+
+ for_each_possible_cpu(i) {
+ void *scratch;
+
+ scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
+ if (!scratch)
+ return NULL;
+ *per_cpu_ptr(scratches, i) = scratch;
+ }
+
+ return scratches;
+}
+
+static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms)
+{
+ struct ipcomp_tfms *pos;
+ int cpu;
+
+ list_for_each_entry(pos, &ipcomp_tfms_list, list) {
+ if (pos->tfms == tfms)
+ break;
+ }
+
+ WARN_ON(!pos);
+
+ if (--pos->users)
+ return;
+
+ list_del(&pos->list);
+ kfree(pos);
+
+ if (!tfms)
+ return;
+
+ for_each_possible_cpu(cpu) {
+ struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
+ crypto_free_comp(tfm);
+ }
+ free_percpu(tfms);
+}
+
+static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
+{
+ struct ipcomp_tfms *pos;
+ struct crypto_comp * __percpu *tfms;
+ int cpu;
+
+
+ list_for_each_entry(pos, &ipcomp_tfms_list, list) {
+ struct crypto_comp *tfm;
+
+ /* This can be any valid CPU ID so we don't need locking. */
+ tfm = __this_cpu_read(*pos->tfms);
+
+ if (!strcmp(crypto_comp_name(tfm), alg_name)) {
+ pos->users++;
+ return pos->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_comp *);
+ if (!tfms)
+ goto error;
+
+ for_each_possible_cpu(cpu) {
+ struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
+ CRYPTO_ALG_ASYNC);
+ if (IS_ERR(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();
+}
+
+void ipcomp_destroy(struct xfrm_state *x)
+{
+ struct ipcomp_data *ipcd = x->data;
+ if (!ipcd)
+ return;
+ xfrm_state_delete_tunnel(x);
+ mutex_lock(&ipcomp_resource_mutex);
+ ipcomp_free_data(ipcd);
+ mutex_unlock(&ipcomp_resource_mutex);
+ kfree(ipcd);
+}
+EXPORT_SYMBOL_GPL(ipcomp_destroy);
+
+int ipcomp_init_state(struct xfrm_state *x)
+{
+ 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 = kzalloc(sizeof(*ipcd), GFP_KERNEL);
+ if (!ipcd)
+ goto out;
+
+ mutex_lock(&ipcomp_resource_mutex);
+ if (!ipcomp_alloc_scratches())
+ goto error;
+
+ ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
+ if (!ipcd->tfms)
+ goto error;
+ mutex_unlock(&ipcomp_resource_mutex);
+
+ 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:
+ ipcomp_free_data(ipcd);
+ mutex_unlock(&ipcomp_resource_mutex);
+ kfree(ipcd);
+ goto out;
+}
+EXPORT_SYMBOL_GPL(ipcomp_init_state);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
+MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
Code Review / kvmfornfv.git / blobdiff