108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
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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/netfilter_ipv4.h>
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#include <net/dst.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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static int xfrm4_tunnel_check_size(struct sk_buff *skb)
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{
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int mtu, ret = 0;
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if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
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goto out;
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if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
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goto out;
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mtu = dst_mtu(skb_dst(skb));
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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, ip_skb_dst_mtu(skb->sk, skb)))) {
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skb->protocol = htons(ETH_P_IP);
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if (skb->sk)
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xfrm_local_error(skb, mtu);
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else
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icmp_send(skb, ICMP_DEST_UNREACH,
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ICMP_FRAG_NEEDED, htonl(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 xfrm4_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 = xfrm4_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 = ip_hdr(skb)->protocol;
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return xfrm4_extract_header(skb);
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}
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int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
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{
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memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
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#ifdef CONFIG_NETFILTER
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IPCB(skb)->flags |= IPSKB_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 __xfrm4_output(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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const struct xfrm_state_afinfo *afinfo;
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int ret = -EAFNOSUPPORT;
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#ifdef CONFIG_NETFILTER
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if (!x) {
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IPCB(skb)->flags |= IPSKB_REROUTED;
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return dst_output(net, sk, skb);
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}
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#endif
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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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int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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net, sk, skb, skb->dev, skb_dst(skb)->dev,
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__xfrm4_output,
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!(IPCB(skb)->flags & IPSKB_REROUTED));
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}
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void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
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{
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struct iphdr *hdr;
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hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
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ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
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inet_sk(skb->sk)->inet_dport, mtu);
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}
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