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/slab.h> 18 #include <linux/spinlock.h> 19 #include <net/dst.h> 20 #include <net/xfrm.h> 21 22 static int xfrm_output2(struct sk_buff *skb); 23 24 static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb) 25 { 26 struct dst_entry *dst = skb_dst(skb); 27 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev) 28 - skb_headroom(skb); 29 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb); 30 31 if (nhead <= 0) { 32 if (ntail <= 0) 33 return 0; 34 nhead = 0; 35 } else if (ntail < 0) 36 ntail = 0; 37 38 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC); 39 } 40 41 static int xfrm_output_one(struct sk_buff *skb, int err) 42 { 43 struct dst_entry *dst = skb_dst(skb); 44 struct xfrm_state *x = dst->xfrm; 45 struct net *net = xs_net(x); 46 47 if (err <= 0) 48 goto resume; 49 50 do { 51 err = xfrm_state_check_space(x, skb); 52 if (err) { 53 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 54 goto error_nolock; 55 } 56 57 err = x->outer_mode->output(x, skb); 58 if (err) { 59 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR); 60 goto error_nolock; 61 } 62 63 spin_lock_bh(&x->lock); 64 err = xfrm_state_check_expire(x); 65 if (err) { 66 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED); 67 goto error; 68 } 69 70 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { 71 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq; 72 if (unlikely(x->replay.oseq == 0)) { 73 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR); 74 x->replay.oseq--; 75 xfrm_audit_state_replay_overflow(x, skb); 76 err = -EOVERFLOW; 77 goto error; 78 } 79 if (xfrm_aevent_is_on(net)) 80 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); 81 } 82 83 x->curlft.bytes += skb->len; 84 x->curlft.packets++; 85 86 spin_unlock_bh(&x->lock); 87 88 err = x->type->output(x, skb); 89 if (err == -EINPROGRESS) 90 goto out_exit; 91 92 resume: 93 if (err) { 94 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR); 95 goto error_nolock; 96 } 97 98 dst = skb_dst_pop(skb); 99 if (!dst) { 100 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 101 err = -EHOSTUNREACH; 102 goto error_nolock; 103 } 104 skb_dst_set_noref(skb, dst); 105 x = dst->xfrm; 106 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 107 108 err = 0; 109 110 out_exit: 111 return err; 112 error: 113 spin_unlock_bh(&x->lock); 114 error_nolock: 115 kfree_skb(skb); 116 goto out_exit; 117 } 118 119 int xfrm_output_resume(struct sk_buff *skb, int err) 120 { 121 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 122 nf_reset(skb); 123 124 err = skb_dst(skb)->ops->local_out(skb); 125 if (unlikely(err != 1)) 126 goto out; 127 128 if (!skb_dst(skb)->xfrm) 129 return dst_output(skb); 130 131 err = nf_hook(skb_dst(skb)->ops->family, 132 NF_INET_POST_ROUTING, skb, 133 NULL, skb_dst(skb)->dev, xfrm_output2); 134 if (unlikely(err != 1)) 135 goto out; 136 } 137 138 if (err == -EINPROGRESS) 139 err = 0; 140 141 out: 142 return err; 143 } 144 EXPORT_SYMBOL_GPL(xfrm_output_resume); 145 146 static int xfrm_output2(struct sk_buff *skb) 147 { 148 return xfrm_output_resume(skb, 1); 149 } 150 151 static int xfrm_output_gso(struct sk_buff *skb) 152 { 153 struct sk_buff *segs; 154 155 segs = skb_gso_segment(skb, 0); 156 kfree_skb(skb); 157 if (IS_ERR(segs)) 158 return PTR_ERR(segs); 159 160 do { 161 struct sk_buff *nskb = segs->next; 162 int err; 163 164 segs->next = NULL; 165 err = xfrm_output2(segs); 166 167 if (unlikely(err)) { 168 while ((segs = nskb)) { 169 nskb = segs->next; 170 segs->next = NULL; 171 kfree_skb(segs); 172 } 173 return err; 174 } 175 176 segs = nskb; 177 } while (segs); 178 179 return 0; 180 } 181 182 int xfrm_output(struct sk_buff *skb) 183 { 184 struct net *net = dev_net(skb_dst(skb)->dev); 185 int err; 186 187 if (skb_is_gso(skb)) 188 return xfrm_output_gso(skb); 189 190 if (skb->ip_summed == CHECKSUM_PARTIAL) { 191 err = skb_checksum_help(skb); 192 if (err) { 193 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 194 kfree_skb(skb); 195 return err; 196 } 197 } 198 199 return xfrm_output2(skb); 200 } 201 202 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 203 { 204 struct xfrm_mode *inner_mode; 205 if (x->sel.family == AF_UNSPEC) 206 inner_mode = xfrm_ip2inner_mode(x, 207 xfrm_af2proto(skb_dst(skb)->ops->family)); 208 else 209 inner_mode = x->inner_mode; 210 211 if (inner_mode == NULL) 212 return -EAFNOSUPPORT; 213 return inner_mode->afinfo->extract_output(x, skb); 214 } 215 216 EXPORT_SYMBOL_GPL(xfrm_output); 217 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output); 218