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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | // SPDX-License-Identifier: GPL-2.0-or-later /* * xfrm4_output.c - Common IPsec encapsulation code for IPv4. * 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/netfilter_ipv4.h> #include <net/dst.h> #include <net/ip.h> #include <net/xfrm.h> #include <net/icmp.h> static int xfrm4_tunnel_check_size(struct sk_buff *skb) { int mtu, ret = 0; if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) goto out; if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df) goto out; mtu = dst_mtu(skb_dst(skb)); if ((!skb_is_gso(skb) && skb->len > mtu) || (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) { skb->protocol = htons(ETH_P_IP); if (skb->sk) xfrm_local_error(skb, mtu); else icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); ret = -EMSGSIZE; } out: return ret; } int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb) { int err; err = xfrm4_tunnel_check_size(skb); if (err) return err; XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol; return xfrm4_extract_header(skb); } int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb) { memset(IPCB(skb), 0, sizeof(*IPCB(skb))); IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; return xfrm_output(sk, skb); } static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb) { struct xfrm_state *x = skb_dst(skb)->xfrm; const struct xfrm_state_afinfo *afinfo; int ret = -EAFNOSUPPORT; #ifdef CONFIG_NETFILTER if (!x) { IPCB(skb)->flags |= IPSKB_REROUTED; return dst_output(net, sk, skb); } #endif 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; } int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb) { return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb, skb->dev, skb_dst(skb)->dev, __xfrm4_output, !(IPCB(skb)->flags & IPSKB_REROUTED)); } void xfrm4_local_error(struct sk_buff *skb, u32 mtu) { struct iphdr *hdr; hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb); ip_local_error(skb->sk, EMSGSIZE, hdr->daddr, inet_sk(skb->sk)->inet_dport, mtu); } |