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![Herbert Xu](/assets/img/avatar_default.png)
Because we use shared tfm objects in order to conserve memory, (each tfm requires 128K of vmalloc memory), BH needs to be turned off on output as that can occur in process context. Previously this was done implicitly by the xfrm output code. That was lost when it became lockless. So we need to add the BH disabling to IPComp directly. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
488 lines
10 KiB
C
488 lines
10 KiB
C
/*
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* IP Payload Compression Protocol (IPComp) - RFC3173.
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*
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* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* Todo:
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* - Tunable compression parameters.
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* - Compression stats.
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* - Adaptive compression.
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*/
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#include <linux/module.h>
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#include <asm/semaphore.h>
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#include <linux/crypto.h>
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#include <linux/err.h>
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#include <linux/pfkeyv2.h>
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#include <linux/percpu.h>
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#include <linux/smp.h>
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#include <linux/list.h>
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#include <linux/vmalloc.h>
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#include <linux/rtnetlink.h>
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#include <linux/mutex.h>
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#include <net/ip.h>
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#include <net/xfrm.h>
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#include <net/icmp.h>
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#include <net/ipcomp.h>
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#include <net/protocol.h>
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struct ipcomp_tfms {
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struct list_head list;
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struct crypto_comp **tfms;
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int users;
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};
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static DEFINE_MUTEX(ipcomp_resource_mutex);
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static void **ipcomp_scratches;
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static int ipcomp_scratch_users;
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static LIST_HEAD(ipcomp_tfms_list);
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static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ipcomp_data *ipcd = x->data;
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const int plen = skb->len;
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int dlen = IPCOMP_SCRATCH_SIZE;
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const u8 *start = skb->data;
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const int cpu = get_cpu();
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u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
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struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
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int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
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if (err)
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goto out;
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if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
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err = -EINVAL;
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goto out;
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}
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err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
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if (err)
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goto out;
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skb->truesize += dlen - plen;
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__skb_put(skb, dlen - plen);
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skb_copy_to_linear_data(skb, scratch, dlen);
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out:
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put_cpu();
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return err;
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}
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static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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int nexthdr;
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int err = -ENOMEM;
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struct ip_comp_hdr *ipch;
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if (skb_linearize_cow(skb))
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goto out;
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skb->ip_summed = CHECKSUM_NONE;
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/* Remove ipcomp header and decompress original payload */
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ipch = (void *)skb->data;
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nexthdr = ipch->nexthdr;
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skb->transport_header = skb->network_header + sizeof(*ipch);
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__skb_pull(skb, sizeof(*ipch));
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err = ipcomp_decompress(x, skb);
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if (err)
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goto out;
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err = nexthdr;
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out:
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return err;
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}
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static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ipcomp_data *ipcd = x->data;
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const int plen = skb->len;
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int dlen = IPCOMP_SCRATCH_SIZE;
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u8 *start = skb->data;
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const int cpu = get_cpu();
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u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
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struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
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int err;
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local_bh_disable();
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err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
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local_bh_enable();
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if (err)
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goto out;
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if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
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err = -EMSGSIZE;
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goto out;
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}
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memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
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put_cpu();
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pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
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return 0;
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out:
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put_cpu();
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return err;
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}
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static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err;
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struct ip_comp_hdr *ipch;
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struct ipcomp_data *ipcd = x->data;
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if (skb->len < ipcd->threshold) {
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/* Don't bother compressing */
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goto out_ok;
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}
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if (skb_linearize_cow(skb))
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goto out_ok;
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err = ipcomp_compress(x, skb);
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if (err) {
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goto out_ok;
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}
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/* Install ipcomp header, convert into ipcomp datagram. */
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ipch = ip_comp_hdr(skb);
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ipch->nexthdr = *skb_mac_header(skb);
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ipch->flags = 0;
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ipch->cpi = htons((u16 )ntohl(x->id.spi));
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*skb_mac_header(skb) = IPPROTO_COMP;
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out_ok:
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skb_push(skb, -skb_network_offset(skb));
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return 0;
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}
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static void ipcomp4_err(struct sk_buff *skb, u32 info)
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{
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__be32 spi;
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struct iphdr *iph = (struct iphdr *)skb->data;
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struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
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struct xfrm_state *x;
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if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
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icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
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return;
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spi = htonl(ntohs(ipch->cpi));
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x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
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spi, IPPROTO_COMP, AF_INET);
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if (!x)
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return;
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NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
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spi, NIPQUAD(iph->daddr));
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xfrm_state_put(x);
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}
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/* We always hold one tunnel user reference to indicate a tunnel */
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static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
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{
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struct xfrm_state *t;
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t = xfrm_state_alloc();
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if (t == NULL)
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goto out;
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t->id.proto = IPPROTO_IPIP;
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t->id.spi = x->props.saddr.a4;
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t->id.daddr.a4 = x->id.daddr.a4;
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memcpy(&t->sel, &x->sel, sizeof(t->sel));
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t->props.family = AF_INET;
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t->props.mode = x->props.mode;
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t->props.saddr.a4 = x->props.saddr.a4;
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t->props.flags = x->props.flags;
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if (xfrm_init_state(t))
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goto error;
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atomic_set(&t->tunnel_users, 1);
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out:
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return t;
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error:
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t->km.state = XFRM_STATE_DEAD;
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xfrm_state_put(t);
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t = NULL;
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goto out;
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}
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/*
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* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
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* always incremented on success.
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*/
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static int ipcomp_tunnel_attach(struct xfrm_state *x)
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{
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int err = 0;
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struct xfrm_state *t;
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t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
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x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
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if (!t) {
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t = ipcomp_tunnel_create(x);
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if (!t) {
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err = -EINVAL;
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goto out;
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}
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xfrm_state_insert(t);
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xfrm_state_hold(t);
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}
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x->tunnel = t;
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atomic_inc(&t->tunnel_users);
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out:
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return err;
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}
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static void ipcomp_free_scratches(void)
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{
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int i;
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void **scratches;
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if (--ipcomp_scratch_users)
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return;
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scratches = ipcomp_scratches;
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if (!scratches)
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return;
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for_each_possible_cpu(i)
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vfree(*per_cpu_ptr(scratches, i));
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free_percpu(scratches);
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}
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static void **ipcomp_alloc_scratches(void)
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{
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int i;
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void **scratches;
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if (ipcomp_scratch_users++)
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return ipcomp_scratches;
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scratches = alloc_percpu(void *);
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if (!scratches)
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return NULL;
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ipcomp_scratches = scratches;
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for_each_possible_cpu(i) {
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void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
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if (!scratch)
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return NULL;
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*per_cpu_ptr(scratches, i) = scratch;
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}
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return scratches;
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}
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static void ipcomp_free_tfms(struct crypto_comp **tfms)
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{
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struct ipcomp_tfms *pos;
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int cpu;
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list_for_each_entry(pos, &ipcomp_tfms_list, list) {
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if (pos->tfms == tfms)
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break;
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}
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BUG_TRAP(pos);
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if (--pos->users)
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return;
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list_del(&pos->list);
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kfree(pos);
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if (!tfms)
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return;
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for_each_possible_cpu(cpu) {
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struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
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crypto_free_comp(tfm);
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}
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free_percpu(tfms);
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}
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static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name)
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{
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struct ipcomp_tfms *pos;
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struct crypto_comp **tfms;
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int cpu;
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/* This can be any valid CPU ID so we don't need locking. */
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cpu = raw_smp_processor_id();
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list_for_each_entry(pos, &ipcomp_tfms_list, list) {
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struct crypto_comp *tfm;
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tfms = pos->tfms;
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tfm = *per_cpu_ptr(tfms, cpu);
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if (!strcmp(crypto_comp_name(tfm), alg_name)) {
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pos->users++;
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return tfms;
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}
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}
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pos = kmalloc(sizeof(*pos), GFP_KERNEL);
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if (!pos)
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return NULL;
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pos->users = 1;
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INIT_LIST_HEAD(&pos->list);
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list_add(&pos->list, &ipcomp_tfms_list);
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pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
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if (!tfms)
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goto error;
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for_each_possible_cpu(cpu) {
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struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
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CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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goto error;
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*per_cpu_ptr(tfms, cpu) = tfm;
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}
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return tfms;
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error:
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ipcomp_free_tfms(tfms);
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return NULL;
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}
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static void ipcomp_free_data(struct ipcomp_data *ipcd)
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{
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if (ipcd->tfms)
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ipcomp_free_tfms(ipcd->tfms);
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ipcomp_free_scratches();
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}
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static void ipcomp_destroy(struct xfrm_state *x)
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{
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struct ipcomp_data *ipcd = x->data;
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if (!ipcd)
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return;
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xfrm_state_delete_tunnel(x);
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mutex_lock(&ipcomp_resource_mutex);
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ipcomp_free_data(ipcd);
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mutex_unlock(&ipcomp_resource_mutex);
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kfree(ipcd);
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}
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static int ipcomp_init_state(struct xfrm_state *x)
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{
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int err;
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struct ipcomp_data *ipcd;
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struct xfrm_algo_desc *calg_desc;
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err = -EINVAL;
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if (!x->calg)
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goto out;
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if (x->encap)
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goto out;
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x->props.header_len = 0;
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switch (x->props.mode) {
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case XFRM_MODE_TRANSPORT:
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break;
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case XFRM_MODE_TUNNEL:
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x->props.header_len += sizeof(struct iphdr);
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break;
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default:
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goto out;
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}
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err = -ENOMEM;
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ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
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if (!ipcd)
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goto out;
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mutex_lock(&ipcomp_resource_mutex);
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if (!ipcomp_alloc_scratches())
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goto error;
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ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
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if (!ipcd->tfms)
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goto error;
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mutex_unlock(&ipcomp_resource_mutex);
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if (x->props.mode == XFRM_MODE_TUNNEL) {
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err = ipcomp_tunnel_attach(x);
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if (err)
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goto error_tunnel;
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}
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calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
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BUG_ON(!calg_desc);
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ipcd->threshold = calg_desc->uinfo.comp.threshold;
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x->data = ipcd;
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err = 0;
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out:
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return err;
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error_tunnel:
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mutex_lock(&ipcomp_resource_mutex);
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error:
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ipcomp_free_data(ipcd);
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mutex_unlock(&ipcomp_resource_mutex);
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kfree(ipcd);
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goto out;
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}
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static const struct xfrm_type ipcomp_type = {
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.description = "IPCOMP4",
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.owner = THIS_MODULE,
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.proto = IPPROTO_COMP,
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.init_state = ipcomp_init_state,
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.destructor = ipcomp_destroy,
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.input = ipcomp_input,
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.output = ipcomp_output
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};
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static struct net_protocol ipcomp4_protocol = {
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.handler = xfrm4_rcv,
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.err_handler = ipcomp4_err,
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.no_policy = 1,
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};
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static int __init ipcomp4_init(void)
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{
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if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
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printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
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return -EAGAIN;
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}
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if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
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printk(KERN_INFO "ipcomp init: can't add protocol\n");
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xfrm_unregister_type(&ipcomp_type, AF_INET);
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return -EAGAIN;
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}
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return 0;
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}
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static void __exit ipcomp4_fini(void)
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{
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if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
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printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
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if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
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printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
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}
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module_init(ipcomp4_init);
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module_exit(ipcomp4_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
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MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
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MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
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