194 lines
4.2 KiB
C
194 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
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* Copyright (C) 2002 USAGI/WIDE Project
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* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <linux/if_ether.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/icmpv6.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/dst.h>
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/xfrm.h>
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int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
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u8 **prevhdr)
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{
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return ip6_find_1stfragopt(skb, prevhdr);
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}
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EXPORT_SYMBOL(xfrm6_find_1stfragopt);
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static int xfrm6_local_dontfrag(struct sk_buff *skb)
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{
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int proto;
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struct sock *sk = skb->sk;
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if (sk) {
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if (sk->sk_family != AF_INET6)
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return 0;
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proto = sk->sk_protocol;
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if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
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return inet6_sk(sk)->dontfrag;
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}
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return 0;
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}
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static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
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{
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struct flowi6 fl6;
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struct sock *sk = skb->sk;
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fl6.flowi6_oif = sk->sk_bound_dev_if;
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fl6.daddr = ipv6_hdr(skb)->daddr;
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ipv6_local_rxpmtu(sk, &fl6, mtu);
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}
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void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
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{
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struct flowi6 fl6;
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const struct ipv6hdr *hdr;
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struct sock *sk = skb->sk;
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hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
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fl6.fl6_dport = inet_sk(sk)->inet_dport;
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fl6.daddr = hdr->daddr;
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ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
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}
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static int xfrm6_tunnel_check_size(struct sk_buff *skb)
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{
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int mtu, ret = 0;
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struct dst_entry *dst = skb_dst(skb);
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if (skb->ignore_df)
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goto out;
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mtu = dst_mtu(dst);
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if (mtu < IPV6_MIN_MTU)
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mtu = IPV6_MIN_MTU;
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if ((!skb_is_gso(skb) && skb->len > mtu) ||
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(skb_is_gso(skb) &&
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!skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
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skb->dev = dst->dev;
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skb->protocol = htons(ETH_P_IPV6);
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if (xfrm6_local_dontfrag(skb))
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xfrm6_local_rxpmtu(skb, mtu);
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else if (skb->sk)
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xfrm_local_error(skb, mtu);
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else
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icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
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ret = -EMSGSIZE;
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}
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out:
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return ret;
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}
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int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err;
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err = xfrm6_tunnel_check_size(skb);
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if (err)
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return err;
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XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
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return xfrm6_extract_header(skb);
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}
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int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
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{
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memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
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#ifdef CONFIG_NETFILTER
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IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
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#endif
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return xfrm_output(sk, skb);
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}
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static int __xfrm6_output_state_finish(struct xfrm_state *x, struct sock *sk,
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struct sk_buff *skb)
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{
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const struct xfrm_state_afinfo *afinfo;
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int ret = -EAFNOSUPPORT;
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rcu_read_lock();
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afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
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if (likely(afinfo))
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ret = afinfo->output_finish(sk, skb);
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else
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kfree_skb(skb);
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rcu_read_unlock();
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return ret;
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}
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static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct xfrm_state *x = skb_dst(skb)->xfrm;
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return __xfrm6_output_state_finish(x, sk, skb);
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}
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static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct xfrm_state *x = dst->xfrm;
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int mtu;
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bool toobig;
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#ifdef CONFIG_NETFILTER
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if (!x) {
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IP6CB(skb)->flags |= IP6SKB_REROUTED;
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return dst_output(net, sk, skb);
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}
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#endif
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if (x->props.mode != XFRM_MODE_TUNNEL)
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goto skip_frag;
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if (skb->protocol == htons(ETH_P_IPV6))
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mtu = ip6_skb_dst_mtu(skb);
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else
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mtu = dst_mtu(skb_dst(skb));
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toobig = skb->len > mtu && !skb_is_gso(skb);
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if (toobig && xfrm6_local_dontfrag(skb)) {
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xfrm6_local_rxpmtu(skb, mtu);
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kfree_skb(skb);
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return -EMSGSIZE;
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} else if (!skb->ignore_df && toobig && skb->sk) {
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xfrm_local_error(skb, mtu);
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kfree_skb(skb);
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return -EMSGSIZE;
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}
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if (toobig || dst_allfrag(skb_dst(skb)))
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return ip6_fragment(net, sk, skb,
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__xfrm6_output_finish);
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skip_frag:
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return __xfrm6_output_state_finish(x, sk, skb);
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}
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int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
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net, sk, skb, skb->dev, skb_dst(skb)->dev,
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__xfrm6_output,
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!(IP6CB(skb)->flags & IP6SKB_REROUTED));
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}
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