diff options
Diffstat (limited to 'net/ipv4/xfrm4_mode_tunnel.c')
| -rw-r--r-- | net/ipv4/xfrm4_mode_tunnel.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c new file mode 100644 index 00000000..e3f64831 --- /dev/null +++ b/net/ipv4/xfrm4_mode_tunnel.c @@ -0,0 +1,193 @@ +/* + * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4. + * + * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> + */ + +#include <linux/gfp.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/stringify.h> +#include <net/dst.h> +#include <net/inet_ecn.h> +#include <net/ip.h> +#include <net/xfrm.h> + +/* Informational hook. The decap is still done here. */ +static struct xfrm_tunnel __rcu *rcv_notify_handlers __read_mostly; +static DEFINE_MUTEX(xfrm4_mode_tunnel_input_mutex); + +int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler) +{ + struct xfrm_tunnel __rcu **pprev; + struct xfrm_tunnel *t; + int ret = -EEXIST; + int priority = handler->priority; + + mutex_lock(&xfrm4_mode_tunnel_input_mutex); + + for (pprev = &rcv_notify_handlers; + (t = rcu_dereference_protected(*pprev, + lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL; + pprev = &t->next) { + if (t->priority > priority) + break; + if (t->priority == priority) + goto err; + + } + + handler->next = *pprev; + rcu_assign_pointer(*pprev, handler); + + ret = 0; + +err: + mutex_unlock(&xfrm4_mode_tunnel_input_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_register); + +int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler) +{ + struct xfrm_tunnel __rcu **pprev; + struct xfrm_tunnel *t; + int ret = -ENOENT; + + mutex_lock(&xfrm4_mode_tunnel_input_mutex); + for (pprev = &rcv_notify_handlers; + (t = rcu_dereference_protected(*pprev, + lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL; + pprev = &t->next) { + if (t == handler) { + *pprev = handler->next; + ret = 0; + break; + } + } + mutex_unlock(&xfrm4_mode_tunnel_input_mutex); + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_deregister); + +static inline void ipip_ecn_decapsulate(struct sk_buff *skb) +{ + struct iphdr *inner_iph = ipip_hdr(skb); + + if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) + IP_ECN_set_ce(inner_iph); +} + +/* Add encapsulation header. + * + * The top IP header will be constructed per RFC 2401. + */ +static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + struct iphdr *top_iph; + int flags; + + skb_set_network_header(skb, -x->props.header_len); + skb->mac_header = skb->network_header + + offsetof(struct iphdr, protocol); + skb->transport_header = skb->network_header + sizeof(*top_iph); + top_iph = ip_hdr(skb); + + top_iph->ihl = 5; + top_iph->version = 4; + + top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); + + /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */ + if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) + top_iph->tos = 0; + else + top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos; + top_iph->tos = INET_ECN_encapsulate(top_iph->tos, + XFRM_MODE_SKB_CB(skb)->tos); + + flags = x->props.flags; + if (flags & XFRM_STATE_NOECN) + IP_ECN_clear(top_iph); + + top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? + 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); + + top_iph->ttl = ip4_dst_hoplimit(dst->child); + + top_iph->saddr = x->props.saddr.a4; + top_iph->daddr = x->id.daddr.a4; + ip_select_ident(skb, NULL); + + return 0; +} + +#define for_each_input_rcu(head, handler) \ + for (handler = rcu_dereference(head); \ + handler != NULL; \ + handler = rcu_dereference(handler->next)) + +static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) +{ + struct xfrm_tunnel *handler; + int err = -EINVAL; + + if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) + goto out; + + if (!pskb_may_pull(skb, sizeof(struct iphdr))) + goto out; + + for_each_input_rcu(rcv_notify_handlers, handler) + handler->handler(skb); + + err = skb_unclone(skb, GFP_ATOMIC); + if (err) + goto out; + + if (x->props.flags & XFRM_STATE_DECAP_DSCP) + ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); + if (!(x->props.flags & XFRM_STATE_NOECN)) + ipip_ecn_decapsulate(skb); + + skb_reset_network_header(skb); + skb_mac_header_rebuild(skb); + + err = 0; + +out: + return err; +} + +static struct xfrm_mode xfrm4_tunnel_mode = { + .input2 = xfrm4_mode_tunnel_input, + .input = xfrm_prepare_input, + .output2 = xfrm4_mode_tunnel_output, + .output = xfrm4_prepare_output, + .owner = THIS_MODULE, + .encap = XFRM_MODE_TUNNEL, + .flags = XFRM_MODE_FLAG_TUNNEL, +}; + +static int __init xfrm4_mode_tunnel_init(void) +{ + return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); +} + +static void __exit xfrm4_mode_tunnel_exit(void) +{ + int err; + + err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); + BUG_ON(err); +} + +module_init(xfrm4_mode_tunnel_init); +module_exit(xfrm4_mode_tunnel_exit); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |