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) { 31 if (ntail <= 0) 32 return 0; 33 nhead = 0; 34 } else if (ntail < 0) 35 ntail = 0; 36 37 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC); 38 } 39 40 static int xfrm_output_one(struct sk_buff *skb, int err) 41 { 42 struct dst_entry *dst = skb->dst; 43 struct xfrm_state *x = dst->xfrm; 44 45 if (err <= 0) 46 goto resume; 47 48 do { 49 err = xfrm_state_check_space(x, skb); 50 if (err) { 51 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 52 goto error_nolock; 53 } 54 55 err = x->outer_mode->output(x, skb); 56 if (err) { 57 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEMODEERROR); 58 goto error_nolock; 59 } 60 61 spin_lock_bh(&x->lock); 62 err = xfrm_state_check_expire(x); 63 if (err) { 64 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEEXPIRED); 65 goto error; 66 } 67 68 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { 69 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq; 70 if (unlikely(x->replay.oseq == 0)) { 71 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATESEQERROR); 72 x->replay.oseq--; 73 xfrm_audit_state_replay_overflow(x, skb); 74 err = -EOVERFLOW; 75 goto error; 76 } 77 if (xfrm_aevent_is_on()) 78 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); 79 } 80 81 x->curlft.bytes += skb->len; 82 x->curlft.packets++; 83 84 spin_unlock_bh(&x->lock); 85 86 err = x->type->output(x, skb); 87 if (err == -EINPROGRESS) 88 goto out_exit; 89 90 resume: 91 if (err) { 92 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEPROTOERROR); 93 goto error_nolock; 94 } 95 96 if (!(skb->dst = dst_pop(dst))) { 97 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 98 err = -EHOSTUNREACH; 99 goto error_nolock; 100 } 101 dst = skb->dst; 102 x = dst->xfrm; 103 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 104 105 err = 0; 106 107 out_exit: 108 return err; 109 error: 110 spin_unlock_bh(&x->lock); 111 error_nolock: 112 kfree_skb(skb); 113 goto out_exit; 114 } 115 116 int xfrm_output_resume(struct sk_buff *skb, int err) 117 { 118 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 119 nf_reset(skb); 120 121 err = skb->dst->ops->local_out(skb); 122 if (unlikely(err != 1)) 123 goto out; 124 125 if (!skb->dst->xfrm) 126 return dst_output(skb); 127 128 err = nf_hook(skb->dst->ops->family, 129 NF_INET_POST_ROUTING, skb, 130 NULL, skb->dst->dev, xfrm_output2); 131 if (unlikely(err != 1)) 132 goto out; 133 } 134 135 if (err == -EINPROGRESS) 136 err = 0; 137 138 out: 139 return err; 140 } 141 EXPORT_SYMBOL_GPL(xfrm_output_resume); 142 143 static int xfrm_output2(struct sk_buff *skb) 144 { 145 return xfrm_output_resume(skb, 1); 146 } 147 148 static int xfrm_output_gso(struct sk_buff *skb) 149 { 150 struct sk_buff *segs; 151 152 segs = skb_gso_segment(skb, 0); 153 kfree_skb(skb); 154 if (IS_ERR(segs)) 155 return PTR_ERR(segs); 156 157 do { 158 struct sk_buff *nskb = segs->next; 159 int err; 160 161 segs->next = NULL; 162 err = xfrm_output2(segs); 163 164 if (unlikely(err)) { 165 while ((segs = nskb)) { 166 nskb = segs->next; 167 segs->next = NULL; 168 kfree_skb(segs); 169 } 170 return err; 171 } 172 173 segs = nskb; 174 } while (segs); 175 176 return 0; 177 } 178 179 int xfrm_output(struct sk_buff *skb) 180 { 181 int err; 182 183 if (skb_is_gso(skb)) 184 return xfrm_output_gso(skb); 185 186 if (skb->ip_summed == CHECKSUM_PARTIAL) { 187 err = skb_checksum_help(skb); 188 if (err) { 189 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR); 190 kfree_skb(skb); 191 return err; 192 } 193 } 194 195 return xfrm_output2(skb); 196 } 197 198 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 199 { 200 struct xfrm_mode *inner_mode; 201 if (x->sel.family == AF_UNSPEC) 202 inner_mode = xfrm_ip2inner_mode(x, 203 xfrm_af2proto(skb->dst->ops->family)); 204 else 205 inner_mode = x->inner_mode; 206 207 if (inner_mode == NULL) 208 return -EAFNOSUPPORT; 209 return inner_mode->afinfo->extract_output(x, skb); 210 } 211 212 EXPORT_SYMBOL_GPL(xfrm_output); 213 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output); 214