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 65 if (unlikely(x->km.state != XFRM_STATE_VALID)) { 66 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID); 67 err = -EINVAL; 68 goto error; 69 } 70 71 err = xfrm_state_check_expire(x); 72 if (err) { 73 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED); 74 goto error; 75 } 76 77 err = x->repl->overflow(x, skb); 78 if (err) { 79 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR); 80 goto error; 81 } 82 83 x->curlft.bytes += skb->len; 84 x->curlft.packets++; 85 86 spin_unlock_bh(&x->lock); 87 88 skb_dst_force(skb); 89 90 err = x->type->output(x, skb); 91 if (err == -EINPROGRESS) 92 goto out; 93 94 resume: 95 if (err) { 96 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR); 97 goto error_nolock; 98 } 99 100 dst = skb_dst_pop(skb); 101 if (!dst) { 102 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 103 err = -EHOSTUNREACH; 104 goto error_nolock; 105 } 106 skb_dst_set(skb, dst); 107 x = dst->xfrm; 108 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL)); 109 110 return 0; 111 112 error: 113 spin_unlock_bh(&x->lock); 114 error_nolock: 115 kfree_skb(skb); 116 out: 117 return err; 118 } 119 120 int xfrm_output_resume(struct sk_buff *skb, int err) 121 { 122 while (likely((err = xfrm_output_one(skb, err)) == 0)) { 123 nf_reset(skb); 124 125 err = skb_dst(skb)->ops->local_out(skb); 126 if (unlikely(err != 1)) 127 goto out; 128 129 if (!skb_dst(skb)->xfrm) 130 return dst_output(skb); 131 132 err = nf_hook(skb_dst(skb)->ops->family, 133 NF_INET_POST_ROUTING, skb, 134 NULL, skb_dst(skb)->dev, xfrm_output2); 135 if (unlikely(err != 1)) 136 goto out; 137 } 138 139 if (err == -EINPROGRESS) 140 err = 0; 141 142 out: 143 return err; 144 } 145 EXPORT_SYMBOL_GPL(xfrm_output_resume); 146 147 static int xfrm_output2(struct sk_buff *skb) 148 { 149 return xfrm_output_resume(skb, 1); 150 } 151 152 static int xfrm_output_gso(struct sk_buff *skb) 153 { 154 struct sk_buff *segs; 155 156 segs = skb_gso_segment(skb, 0); 157 kfree_skb(skb); 158 if (IS_ERR(segs)) 159 return PTR_ERR(segs); 160 161 do { 162 struct sk_buff *nskb = segs->next; 163 int err; 164 165 segs->next = NULL; 166 err = xfrm_output2(segs); 167 168 if (unlikely(err)) { 169 while ((segs = nskb)) { 170 nskb = segs->next; 171 segs->next = NULL; 172 kfree_skb(segs); 173 } 174 return err; 175 } 176 177 segs = nskb; 178 } while (segs); 179 180 return 0; 181 } 182 183 int xfrm_output(struct sk_buff *skb) 184 { 185 struct net *net = dev_net(skb_dst(skb)->dev); 186 int err; 187 188 if (skb_is_gso(skb)) 189 return xfrm_output_gso(skb); 190 191 if (skb->ip_summed == CHECKSUM_PARTIAL) { 192 err = skb_checksum_help(skb); 193 if (err) { 194 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); 195 kfree_skb(skb); 196 return err; 197 } 198 } 199 200 return xfrm_output2(skb); 201 } 202 203 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 204 { 205 struct xfrm_mode *inner_mode; 206 if (x->sel.family == AF_UNSPEC) 207 inner_mode = xfrm_ip2inner_mode(x, 208 xfrm_af2proto(skb_dst(skb)->ops->family)); 209 else 210 inner_mode = x->inner_mode; 211 212 if (inner_mode == NULL) 213 return -EAFNOSUPPORT; 214 return inner_mode->afinfo->extract_output(x, skb); 215 } 216 217 void xfrm_local_error(struct sk_buff *skb, int mtu) 218 { 219 unsigned int proto; 220 struct xfrm_state_afinfo *afinfo; 221 222 if (skb->protocol == htons(ETH_P_IP)) 223 proto = AF_INET; 224 else if (skb->protocol == htons(ETH_P_IPV6)) 225 proto = AF_INET6; 226 else 227 return; 228 229 afinfo = xfrm_state_get_afinfo(proto); 230 if (!afinfo) 231 return; 232 233 afinfo->local_error(skb, mtu); 234 xfrm_state_put_afinfo(afinfo); 235 } 236 237 EXPORT_SYMBOL_GPL(xfrm_output); 238 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output); 239 EXPORT_SYMBOL_GPL(xfrm_local_error); 240