1 /* 2 * xfrm_output.c - Common IPsec encapsulation code. 3 * 4 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #include <linux/errno.h> 13 #include <linux/module.h> 14 #include <linux/netdevice.h> 15 #include <linux/skbuff.h> 16 #include <linux/spinlock.h> 17 #include <net/dst.h> 18 #include <net/xfrm.h> 19 20 static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb) 21 { 22 int nhead = x->props.header_len + LL_RESERVED_SPACE(skb->dst->dev) 23 - skb_headroom(skb); 24 25 if (nhead > 0) 26 return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC); 27 28 /* Check tail too... */ 29 return 0; 30 } 31 32 static int xfrm_state_check(struct xfrm_state *x, struct sk_buff *skb) 33 { 34 int err = xfrm_state_check_expire(x); 35 if (err < 0) 36 goto err; 37 err = xfrm_state_check_space(x, skb); 38 err: 39 return err; 40 } 41 42 int xfrm_output(struct sk_buff *skb) 43 { 44 struct dst_entry *dst = skb->dst; 45 struct xfrm_state *x = dst->xfrm; 46 int err; 47 48 if (skb->ip_summed == CHECKSUM_PARTIAL) { 49 err = skb_checksum_help(skb); 50 if (err) 51 goto error_nolock; 52 } 53 54 do { 55 spin_lock_bh(&x->lock); 56 err = xfrm_state_check(x, skb); 57 if (err) 58 goto error; 59 60 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { 61 XFRM_SKB_CB(skb)->seq = ++x->replay.oseq; 62 if (xfrm_aevent_is_on()) 63 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); 64 } 65 66 err = x->mode->output(x, skb); 67 if (err) 68 goto error; 69 70 x->curlft.bytes += skb->len; 71 x->curlft.packets++; 72 73 spin_unlock_bh(&x->lock); 74 75 err = x->type->output(x, skb); 76 if (err) 77 goto error_nolock; 78 79 if (!(skb->dst = dst_pop(dst))) { 80 err = -EHOSTUNREACH; 81 goto error_nolock; 82 } 83 dst = skb->dst; 84 x = dst->xfrm; 85 } while (x && (x->props.mode != XFRM_MODE_TUNNEL)); 86 87 err = 0; 88 89 error_nolock: 90 return err; 91 error: 92 spin_unlock_bh(&x->lock); 93 goto error_nolock; 94 } 95 EXPORT_SYMBOL_GPL(xfrm_output); 96