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(skb); 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(skb); 43 struct xfrm_state *x = dst->xfrm; 44 struct net *net = xs_net(x); 45 46 if (err <= 0) 47 goto resume; 48 49 do { 50 err = xfrm_state_check_space(x, skb); 51 if (err) { 52 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 53 goto error_nolock; 54 } 55 56 err = x->outer_mode->output(x, skb); 57 if (err) { 58 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR); 59 goto error_nolock; 60 } 61 62 spin_lock_bh(&x->lock); 63 err = xfrm_state_check_expire(x); 64 if (err) { 65 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED); 66 goto error; 67 } 68 69 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { 70 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq; 71 if (unlikely(x->replay.oseq == 0)) { 72 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR); 73 x->replay.oseq--; 74 xfrm_audit_state_replay_overflow(x, skb); 75 err = -EOVERFLOW; 76 goto error; 77 } 78 if (xfrm_aevent_is_on(net)) 79 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); 80 } 81 82 x->curlft.bytes += skb->len; 83 x->curlft.packets++; 84 85 spin_unlock_bh(&x->lock); 86 87 err = x->type->output(x, skb); 88 if (err == -EINPROGRESS) 89 goto out_exit; 90 91 resume: 92 if (err) { 93 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR); 94 goto error_nolock; 95 } 96 97 dst = dst_pop(dst); 98 if (!dst) { 99 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 100 err = -EHOSTUNREACH; 101 goto error_nolock; 102 } 103 skb_dst_set(skb, dst); 104 x = dst->xfrm; 105 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 106 107 err = 0; 108 109 out_exit: 110 return err; 111 error: 112 spin_unlock_bh(&x->lock); 113 error_nolock: 114 kfree_skb(skb); 115 goto out_exit; 116 } 117 118 int xfrm_output_resume(struct sk_buff *skb, int err) 119 { 120 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 121 nf_reset(skb); 122 123 err = skb_dst(skb)->ops->local_out(skb); 124 if (unlikely(err != 1)) 125 goto out; 126 127 if (!skb_dst(skb)->xfrm) 128 return dst_output(skb); 129 130 err = nf_hook(skb_dst(skb)->ops->family, 131 NF_INET_POST_ROUTING, skb, 132 NULL, skb_dst(skb)->dev, xfrm_output2); 133 if (unlikely(err != 1)) 134 goto out; 135 } 136 137 if (err == -EINPROGRESS) 138 err = 0; 139 140 out: 141 return err; 142 } 143 EXPORT_SYMBOL_GPL(xfrm_output_resume); 144 145 static int xfrm_output2(struct sk_buff *skb) 146 { 147 return xfrm_output_resume(skb, 1); 148 } 149 150 static int xfrm_output_gso(struct sk_buff *skb) 151 { 152 struct sk_buff *segs; 153 154 segs = skb_gso_segment(skb, 0); 155 kfree_skb(skb); 156 if (IS_ERR(segs)) 157 return PTR_ERR(segs); 158 159 do { 160 struct sk_buff *nskb = segs->next; 161 int err; 162 163 segs->next = NULL; 164 err = xfrm_output2(segs); 165 166 if (unlikely(err)) { 167 while ((segs = nskb)) { 168 nskb = segs->next; 169 segs->next = NULL; 170 kfree_skb(segs); 171 } 172 return err; 173 } 174 175 segs = nskb; 176 } while (segs); 177 178 return 0; 179 } 180 181 int xfrm_output(struct sk_buff *skb) 182 { 183 struct net *net = dev_net(skb_dst(skb)->dev); 184 int err; 185 186 if (skb_is_gso(skb)) 187 return xfrm_output_gso(skb); 188 189 if (skb->ip_summed == CHECKSUM_PARTIAL) { 190 err = skb_checksum_help(skb); 191 if (err) { 192 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 193 kfree_skb(skb); 194 return err; 195 } 196 } 197 198 return xfrm_output2(skb); 199 } 200 201 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 202 { 203 struct xfrm_mode *inner_mode; 204 if (x->sel.family == AF_UNSPEC) 205 inner_mode = xfrm_ip2inner_mode(x, 206 xfrm_af2proto(skb_dst(skb)->ops->family)); 207 else 208 inner_mode = x->inner_mode; 209 210 if (inner_mode == NULL) 211 return -EAFNOSUPPORT; 212 return inner_mode->afinfo->extract_output(x, skb); 213 } 214 215 EXPORT_SYMBOL_GPL(xfrm_output); 216 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output); 217