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_skb_check_space(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_skb_check_space(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 err = x->repl->overflow(x, skb); 71 if (err) { 72 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR); 73 goto error; 74 } 75 76 x->curlft.bytes += skb->len; 77 x->curlft.packets++; 78 79 spin_unlock_bh(&x->lock); 80 81 skb_dst_force(skb); 82 83 err = x->type->output(x, skb); 84 if (err == -EINPROGRESS) 85 goto out_exit; 86 87 resume: 88 if (err) { 89 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR); 90 goto error_nolock; 91 } 92 93 dst = skb_dst_pop(skb); 94 if (!dst) { 95 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 96 err = -EHOSTUNREACH; 97 goto error_nolock; 98 } 99 skb_dst_set(skb, dst); 100 x = dst->xfrm; 101 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 102 103 err = 0; 104 105 out_exit: 106 return err; 107 error: 108 spin_unlock_bh(&x->lock); 109 error_nolock: 110 kfree_skb(skb); 111 goto out_exit; 112 } 113 114 int xfrm_output_resume(struct sk_buff *skb, int err) 115 { 116 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 117 nf_reset(skb); 118 119 err = skb_dst(skb)->ops->local_out(skb); 120 if (unlikely(err != 1)) 121 goto out; 122 123 if (!skb_dst(skb)->xfrm) 124 return dst_output(skb); 125 126 err = nf_hook(skb_dst(skb)->ops->family, 127 NF_INET_POST_ROUTING, skb, 128 NULL, skb_dst(skb)->dev, xfrm_output2); 129 if (unlikely(err != 1)) 130 goto out; 131 } 132 133 if (err == -EINPROGRESS) 134 err = 0; 135 136 out: 137 return err; 138 } 139 EXPORT_SYMBOL_GPL(xfrm_output_resume); 140 141 static int xfrm_output2(struct sk_buff *skb) 142 { 143 return xfrm_output_resume(skb, 1); 144 } 145 146 static int xfrm_output_gso(struct sk_buff *skb) 147 { 148 struct sk_buff *segs; 149 150 segs = skb_gso_segment(skb, 0); 151 kfree_skb(skb); 152 if (IS_ERR(segs)) 153 return PTR_ERR(segs); 154 155 do { 156 struct sk_buff *nskb = segs->next; 157 int err; 158 159 segs->next = NULL; 160 err = xfrm_output2(segs); 161 162 if (unlikely(err)) { 163 while ((segs = nskb)) { 164 nskb = segs->next; 165 segs->next = NULL; 166 kfree_skb(segs); 167 } 168 return err; 169 } 170 171 segs = nskb; 172 } while (segs); 173 174 return 0; 175 } 176 177 int xfrm_output(struct sk_buff *skb) 178 { 179 struct net *net = dev_net(skb_dst(skb)->dev); 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(net, 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(skb)->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