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/netfilter.h> 16 #include <linux/skbuff.h> 17 #include <linux/spinlock.h> 18 #include <net/dst.h> 19 #include <net/xfrm.h> 20 21 static int xfrm_output2(struct sk_buff *skb); 22 23 static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb) 24 { 25 struct dst_entry *dst = skb->dst; 26 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev) 27 - skb_headroom(skb); 28 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb); 29 30 if (nhead > 0 || ntail > 0) 31 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC); 32 33 return 0; 34 } 35 36 static int xfrm_output_one(struct sk_buff *skb, int err) 37 { 38 struct dst_entry *dst = skb->dst; 39 struct xfrm_state *x = dst->xfrm; 40 41 if (err <= 0) 42 goto resume; 43 44 do { 45 err = xfrm_state_check_space(x, skb); 46 if (err) { 47 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 48 goto error_nolock; 49 } 50 51 err = x->outer_mode->output(x, skb); 52 if (err) { 53 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEMODEERROR); 54 goto error_nolock; 55 } 56 57 spin_lock_bh(&x->lock); 58 err = xfrm_state_check_expire(x); 59 if (err) { 60 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEEXPIRED); 61 goto error; 62 } 63 64 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { 65 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq; 66 if (unlikely(x->replay.oseq == 0)) { 67 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATESEQERROR); 68 x->replay.oseq--; 69 xfrm_audit_state_replay_overflow(x, skb); 70 err = -EOVERFLOW; 71 goto error; 72 } 73 if (xfrm_aevent_is_on()) 74 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); 75 } 76 77 x->curlft.bytes += skb->len; 78 x->curlft.packets++; 79 80 spin_unlock_bh(&x->lock); 81 82 err = x->type->output(x, skb); 83 if (err == -EINPROGRESS) 84 goto out_exit; 85 86 resume: 87 if (err) { 88 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEPROTOERROR); 89 goto error_nolock; 90 } 91 92 if (!(skb->dst = dst_pop(dst))) { 93 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 94 err = -EHOSTUNREACH; 95 goto error_nolock; 96 } 97 dst = skb->dst; 98 x = dst->xfrm; 99 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 100 101 err = 0; 102 103 out_exit: 104 return err; 105 error: 106 spin_unlock_bh(&x->lock); 107 error_nolock: 108 kfree_skb(skb); 109 goto out_exit; 110 } 111 112 int xfrm_output_resume(struct sk_buff *skb, int err) 113 { 114 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 115 struct xfrm_state *x; 116 117 nf_reset(skb); 118 119 err = skb->dst->ops->local_out(skb); 120 if (unlikely(err != 1)) 121 goto out; 122 123 x = skb->dst->xfrm; 124 if (!x) 125 return dst_output(skb); 126 127 err = nf_hook(skb->dst->ops->family, 128 NF_INET_POST_ROUTING, skb, 129 NULL, skb->dst->dev, xfrm_output2); 130 if (unlikely(err != 1)) 131 goto out; 132 } 133 134 if (err == -EINPROGRESS) 135 err = 0; 136 137 out: 138 return err; 139 } 140 EXPORT_SYMBOL_GPL(xfrm_output_resume); 141 142 static int xfrm_output2(struct sk_buff *skb) 143 { 144 return xfrm_output_resume(skb, 1); 145 } 146 147 static int xfrm_output_gso(struct sk_buff *skb) 148 { 149 struct sk_buff *segs; 150 151 segs = skb_gso_segment(skb, 0); 152 kfree_skb(skb); 153 if (IS_ERR(segs)) 154 return PTR_ERR(segs); 155 156 do { 157 struct sk_buff *nskb = segs->next; 158 int err; 159 160 segs->next = NULL; 161 err = xfrm_output2(segs); 162 163 if (unlikely(err)) { 164 while ((segs = nskb)) { 165 nskb = segs->next; 166 segs->next = NULL; 167 kfree_skb(segs); 168 } 169 return err; 170 } 171 172 segs = nskb; 173 } while (segs); 174 175 return 0; 176 } 177 178 int xfrm_output(struct sk_buff *skb) 179 { 180 int err; 181 182 if (skb_is_gso(skb)) 183 return xfrm_output_gso(skb); 184 185 if (skb->ip_summed == CHECKSUM_PARTIAL) { 186 err = skb_checksum_help(skb); 187 if (err) { 188 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 189 kfree_skb(skb); 190 return err; 191 } 192 } 193 194 return xfrm_output2(skb); 195 } 196 197 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 198 { 199 struct xfrm_mode *inner_mode; 200 if (x->sel.family == AF_UNSPEC) 201 inner_mode = xfrm_ip2inner_mode(x, 202 xfrm_af2proto(skb->dst->ops->family)); 203 else 204 inner_mode = x->inner_mode; 205 206 if (inner_mode == NULL) 207 return -EAFNOSUPPORT; 208 return inner_mode->afinfo->extract_output(x, skb); 209 } 210 211 EXPORT_SYMBOL_GPL(xfrm_output); 212 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output); 213