diff options
Diffstat (limited to 'net/ipv6/xfrm6_output.c')
| -rw-r--r-- | net/ipv6/xfrm6_output.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c new file mode 100644 index 000000000..fbcec4827 --- /dev/null +++ b/net/ipv6/xfrm6_output.c @@ -0,0 +1,209 @@ +/* + * xfrm6_output.c - Common IPsec encapsulation code for IPv6. + * Copyright (C) 2002 USAGI/WIDE Project + * Copyright (c) 2004 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. + */ + +#include <linux/if_ether.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/icmpv6.h> +#include <linux/netfilter_ipv6.h> +#include <net/dst.h> +#include <net/ipv6.h> +#include <net/ip6_route.h> +#include <net/xfrm.h> + +int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, + u8 **prevhdr) +{ + return ip6_find_1stfragopt(skb, prevhdr); +} +EXPORT_SYMBOL(xfrm6_find_1stfragopt); + +static int xfrm6_local_dontfrag(struct sk_buff *skb) +{ + int proto; + struct sock *sk = skb->sk; + + if (sk) { + if (sk->sk_family != AF_INET6) + return 0; + + proto = sk->sk_protocol; + if (proto == IPPROTO_UDP || proto == IPPROTO_RAW) + return inet6_sk(sk)->dontfrag; + } + + return 0; +} + +static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) +{ + struct flowi6 fl6; + struct sock *sk = skb->sk; + + fl6.flowi6_oif = sk->sk_bound_dev_if; + fl6.daddr = ipv6_hdr(skb)->daddr; + + ipv6_local_rxpmtu(sk, &fl6, mtu); +} + +void xfrm6_local_error(struct sk_buff *skb, u32 mtu) +{ + struct flowi6 fl6; + const struct ipv6hdr *hdr; + struct sock *sk = skb->sk; + + hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb); + fl6.fl6_dport = inet_sk(sk)->inet_dport; + fl6.daddr = hdr->daddr; + + ipv6_local_error(sk, EMSGSIZE, &fl6, mtu); +} + +static int xfrm6_tunnel_check_size(struct sk_buff *skb) +{ + int mtu, ret = 0; + struct dst_entry *dst = skb_dst(skb); + + if (skb->ignore_df) + goto out; + + mtu = dst_mtu(dst); + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + + if ((!skb_is_gso(skb) && skb->len > mtu) || + (skb_is_gso(skb) && + !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) { + skb->dev = dst->dev; + skb->protocol = htons(ETH_P_IPV6); + + if (xfrm6_local_dontfrag(skb)) + xfrm6_local_rxpmtu(skb, mtu); + else if (skb->sk) + xfrm_local_error(skb, mtu); + else + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); + ret = -EMSGSIZE; + } +out: + return ret; +} + +int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb) +{ + int err; + + err = xfrm6_tunnel_check_size(skb); + if (err) + return err; + + XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr; + + return xfrm6_extract_header(skb); +} + +int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb) +{ + int err; + + err = xfrm_inner_extract_output(x, skb); + if (err) + return err; + + skb->ignore_df = 1; + skb->protocol = htons(ETH_P_IPV6); + + return x->outer_mode->output2(x, skb); +} +EXPORT_SYMBOL(xfrm6_prepare_output); + +int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb) +{ + memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); + + IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED; + + return xfrm_output(sk, skb); +} + +static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct xfrm_state *x = skb_dst(skb)->xfrm; + + return x->outer_mode->afinfo->output_finish(sk, skb); +} + +static int xfrm6_noneed_fragment(struct sk_buff *skb) +{ + struct frag_hdr *fh; + u8 prevhdr = ipv6_hdr(skb)->nexthdr; + + if (prevhdr != NEXTHDR_FRAGMENT) + return 0; + fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr)); + if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH) + return 1; + return 0; +} + +static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + struct xfrm_state *x = dst->xfrm; + unsigned int mtu; + bool toobig; + +#ifdef CONFIG_NETFILTER + if (!x) { + IP6CB(skb)->flags |= IP6SKB_REROUTED; + return dst_output(net, sk, skb); + } +#endif + + if (x->props.mode != XFRM_MODE_TUNNEL) + goto skip_frag; + + if (skb->protocol == htons(ETH_P_IPV6)) + mtu = ip6_skb_dst_mtu(skb); + else + mtu = dst_mtu(skb_dst(skb)); + + toobig = skb->len > mtu && !skb_is_gso(skb); + + if (toobig && xfrm6_local_dontfrag(skb)) { + xfrm6_local_rxpmtu(skb, mtu); + kfree_skb(skb); + return -EMSGSIZE; + } else if (toobig && xfrm6_noneed_fragment(skb)) { + skb->ignore_df = 1; + goto skip_frag; + } else if (!skb->ignore_df && toobig && skb->sk) { + xfrm_local_error(skb, mtu); + kfree_skb(skb); + return -EMSGSIZE; + } + + if (toobig || dst_allfrag(skb_dst(skb))) + return ip6_fragment(net, sk, skb, + __xfrm6_output_finish); + +skip_frag: + return x->outer_mode->afinfo->output_finish(sk, skb); +} + +int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, + net, sk, skb, NULL, skb_dst(skb)->dev, + __xfrm6_output, + !(IP6CB(skb)->flags & IP6SKB_REROUTED)); +} |