/* * 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>");