/* * xfrm4_output.c - Common IPsec encapsulation code for IPv4. * 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/compiler.h> #include <linux/if_ether.h> #include <linux/kernel.h> #include <linux/skbuff.h> #include <linux/spinlock.h> #include <linux/netfilter_ipv4.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; struct dst_entry *dst; if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) goto out; IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df) goto out; dst = skb->dst; mtu = dst_mtu(dst); if (skb->len > mtu) { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); ret = -EMSGSIZE; } out: return ret; } static int xfrm4_output_one(struct sk_buff *skb) { struct dst_entry *dst = skb->dst; struct xfrm_state *x = dst->xfrm; int err; if (skb->ip_summed == CHECKSUM_PARTIAL) { err = skb_checksum_help(skb); if (err) goto error_nolock; } if (x->props.mode == XFRM_MODE_TUNNEL) { err = xfrm4_tunnel_check_size(skb); if (err) goto error_nolock; } do { spin_lock_bh(&x->lock); err = xfrm_state_check(x, skb); if (err) goto error; err = x->mode->output(x, skb); if (err) goto error; err = x->type->output(x, skb); if (err) goto error; x->curlft.bytes += skb->len; x->curlft.packets++; spin_unlock_bh(&x->lock); if (!(skb->dst = dst_pop(dst))) { err = -EHOSTUNREACH; goto error_nolock; } dst = skb->dst; x = dst->xfrm; } while (x && (x->props.mode != XFRM_MODE_TUNNEL)); IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; err = 0; out_exit: return err; error: spin_unlock_bh(&x->lock); error_nolock: kfree_skb(skb); goto out_exit; } static int xfrm4_output_finish2(struct sk_buff *skb) { int err; while (likely((err = xfrm4_output_one(skb)) == 0)) { nf_reset(skb); err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL, skb->dst->dev, dst_output); if (unlikely(err != 1)) break; if (!skb->dst->xfrm) return dst_output(skb); err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL, skb->dst->dev, xfrm4_output_finish2); if (unlikely(err != 1)) break; } return err; } static int xfrm4_output_finish(struct sk_buff *skb) { struct sk_buff *segs; #ifdef CONFIG_NETFILTER if (!skb->dst->xfrm) { IPCB(skb)->flags |= IPSKB_REROUTED; return dst_output(skb); } #endif if (!skb_is_gso(skb)) return xfrm4_output_finish2(skb); skb->protocol = htons(ETH_P_IP); segs = skb_gso_segment(skb, 0); kfree_skb(skb); if (unlikely(IS_ERR(segs))) return PTR_ERR(segs); do { struct sk_buff *nskb = segs->next; int err; segs->next = NULL; err = xfrm4_output_finish2(segs); if (unlikely(err)) { while ((segs = nskb)) { nskb = segs->next; segs->next = NULL; kfree_skb(segs); } return err; } segs = nskb; } while (segs); return 0; } int xfrm4_output(struct sk_buff *skb) { return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev, xfrm4_output_finish, !(IPCB(skb)->flags & IPSKB_REROUTED)); }