| /* |
| * 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/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; |
| struct dst_entry *dst; |
| |
| if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) |
| goto out; |
| |
| 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; |
| } |
| |
| int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| int err; |
| |
| err = xfrm4_tunnel_check_size(skb); |
| if (err) |
| return err; |
| |
| return xfrm4_extract_header(skb); |
| } |
| |
| int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| int err; |
| |
| err = x->inner_mode->afinfo->extract_output(x, skb); |
| if (err) |
| return err; |
| |
| memset(IPCB(skb), 0, sizeof(*IPCB(skb))); |
| IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; |
| |
| skb->protocol = htons(ETH_P_IP); |
| |
| return x->outer_mode->output2(x, skb); |
| } |
| EXPORT_SYMBOL(xfrm4_prepare_output); |
| |
| static inline int xfrm4_output_one(struct sk_buff *skb) |
| { |
| struct iphdr *iph; |
| int err; |
| |
| err = xfrm_output(skb); |
| if (err) |
| goto error_nolock; |
| |
| iph = ip_hdr(skb); |
| iph->tot_len = htons(skb->len); |
| ip_send_check(iph); |
| |
| IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; |
| err = 0; |
| |
| out_exit: |
| return err; |
| 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)); |
| } |