/net/ipv6/xfrm6_output.c
http://github.com/mirrors/linux · C · 191 lines · 147 code · 38 blank · 6 comment · 30 complexity · 815f27fcabd6648c8ce29a8e9cf77a86 MD5 · raw file
- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * 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>
- */
- #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_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_state_finish(struct xfrm_state *x, struct sock *sk,
- struct sk_buff *skb)
- {
- const struct xfrm_state_afinfo *afinfo;
- int ret = -EAFNOSUPPORT;
- rcu_read_lock();
- afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
- if (likely(afinfo))
- ret = afinfo->output_finish(sk, skb);
- else
- kfree_skb(skb);
- rcu_read_unlock();
- return ret;
- }
- static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
- {
- struct xfrm_state *x = skb_dst(skb)->xfrm;
- return __xfrm6_output_state_finish(x, sk, skb);
- }
- 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;
- 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 (!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 __xfrm6_output_state_finish(x, 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, skb->dev, skb_dst(skb)->dev,
- __xfrm6_output,
- !(IP6CB(skb)->flags & IP6SKB_REROUTED));
- }