diff options
Diffstat (limited to 'net/ipv4/ipcomp.c')
-rw-r--r-- | net/ipv4/ipcomp.c | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c new file mode 100644 index 000000000000..1a23c5263b99 --- /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>"); + |