1 /* 2 * xfrm_input.c 3 * 4 * Changes: 5 * YOSHIFUJI Hideaki @USAGI 6 * Split up af-specific portion 7 * 8 */ 9 10 #include <linux/slab.h> 11 #include <linux/module.h> 12 #include <linux/netdevice.h> 13 #include <net/dst.h> 14 #include <net/ip.h> 15 #include <net/xfrm.h> 16 17 static struct kmem_cache *secpath_cachep __read_mostly; 18 19 void __secpath_destroy(struct sec_path *sp) 20 { 21 int i; 22 for (i = 0; i < sp->len; i++) 23 xfrm_state_put(sp->xvec[i]); 24 kmem_cache_free(secpath_cachep, sp); 25 } 26 EXPORT_SYMBOL(__secpath_destroy); 27 28 struct sec_path *secpath_dup(struct sec_path *src) 29 { 30 struct sec_path *sp; 31 32 sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC); 33 if (!sp) 34 return NULL; 35 36 sp->len = 0; 37 if (src) { 38 int i; 39 40 memcpy(sp, src, sizeof(*sp)); 41 for (i = 0; i < sp->len; i++) 42 xfrm_state_hold(sp->xvec[i]); 43 } 44 atomic_set(&sp->refcnt, 1); 45 return sp; 46 } 47 EXPORT_SYMBOL(secpath_dup); 48 49 /* Fetch spi and seq from ipsec header */ 50 51 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq) 52 { 53 int offset, offset_seq; 54 int hlen; 55 56 switch (nexthdr) { 57 case IPPROTO_AH: 58 hlen = sizeof(struct ip_auth_hdr); 59 offset = offsetof(struct ip_auth_hdr, spi); 60 offset_seq = offsetof(struct ip_auth_hdr, seq_no); 61 break; 62 case IPPROTO_ESP: 63 hlen = sizeof(struct ip_esp_hdr); 64 offset = offsetof(struct ip_esp_hdr, spi); 65 offset_seq = offsetof(struct ip_esp_hdr, seq_no); 66 break; 67 case IPPROTO_COMP: 68 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr))) 69 return -EINVAL; 70 *spi = htonl(ntohs(*(__be16*)(skb_transport_header(skb) + 2))); 71 *seq = 0; 72 return 0; 73 default: 74 return 1; 75 } 76 77 if (!pskb_may_pull(skb, hlen)) 78 return -EINVAL; 79 80 *spi = *(__be32*)(skb_transport_header(skb) + offset); 81 *seq = *(__be32*)(skb_transport_header(skb) + offset_seq); 82 return 0; 83 } 84 85 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb) 86 { 87 int err; 88 89 err = x->outer_mode->afinfo->extract_input(x, skb); 90 if (err) 91 return err; 92 93 skb->protocol = x->inner_mode->afinfo->eth_proto; 94 return x->inner_mode->input2(x, skb); 95 } 96 EXPORT_SYMBOL(xfrm_prepare_input); 97 98 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) 99 { 100 int err; 101 __be32 seq; 102 struct xfrm_state *x; 103 xfrm_address_t *daddr; 104 unsigned int family; 105 int decaps = 0; 106 int async = 0; 107 108 /* A negative encap_type indicates async resumption. */ 109 if (encap_type < 0) { 110 async = 1; 111 x = xfrm_input_state(skb); 112 seq = XFRM_SKB_CB(skb)->seq; 113 goto resume; 114 } 115 116 /* Allocate new secpath or COW existing one. */ 117 if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { 118 struct sec_path *sp; 119 120 sp = secpath_dup(skb->sp); 121 if (!sp) { 122 XFRM_INC_STATS(LINUX_MIB_XFRMINERROR); 123 goto drop; 124 } 125 if (skb->sp) 126 secpath_put(skb->sp); 127 skb->sp = sp; 128 } 129 130 daddr = (xfrm_address_t *)(skb_network_header(skb) + 131 XFRM_SPI_SKB_CB(skb)->daddroff); 132 family = XFRM_SPI_SKB_CB(skb)->family; 133 134 seq = 0; 135 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) { 136 XFRM_INC_STATS(LINUX_MIB_XFRMINHDRERROR); 137 goto drop; 138 } 139 140 do { 141 if (skb->sp->len == XFRM_MAX_DEPTH) { 142 XFRM_INC_STATS(LINUX_MIB_XFRMINBUFFERERROR); 143 goto drop; 144 } 145 146 x = xfrm_state_lookup(daddr, spi, nexthdr, family); 147 if (x == NULL) { 148 XFRM_INC_STATS(LINUX_MIB_XFRMINNOSTATES); 149 xfrm_audit_state_notfound(skb, family, spi, seq); 150 goto drop; 151 } 152 153 skb->sp->xvec[skb->sp->len++] = x; 154 155 spin_lock(&x->lock); 156 if (unlikely(x->km.state != XFRM_STATE_VALID)) { 157 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEINVALID); 158 goto drop_unlock; 159 } 160 161 if ((x->encap ? x->encap->encap_type : 0) != encap_type) { 162 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEMISMATCH); 163 goto drop_unlock; 164 } 165 166 if (x->props.replay_window && xfrm_replay_check(x, skb, seq)) { 167 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATESEQERROR); 168 goto drop_unlock; 169 } 170 171 if (xfrm_state_check_expire(x)) { 172 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEEXPIRED); 173 goto drop_unlock; 174 } 175 176 spin_unlock(&x->lock); 177 178 XFRM_SKB_CB(skb)->seq = seq; 179 180 nexthdr = x->type->input(x, skb); 181 182 if (nexthdr == -EINPROGRESS) 183 return 0; 184 185 resume: 186 spin_lock(&x->lock); 187 if (nexthdr <= 0) { 188 if (nexthdr == -EBADMSG) { 189 xfrm_audit_state_icvfail(x, skb, 190 x->type->proto); 191 x->stats.integrity_failed++; 192 } 193 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEPROTOERROR); 194 goto drop_unlock; 195 } 196 197 /* only the first xfrm gets the encap type */ 198 encap_type = 0; 199 200 if (x->props.replay_window) 201 xfrm_replay_advance(x, seq); 202 203 x->curlft.bytes += skb->len; 204 x->curlft.packets++; 205 206 spin_unlock(&x->lock); 207 208 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr; 209 210 if (x->inner_mode->input(x, skb)) { 211 XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEMODEERROR); 212 goto drop; 213 } 214 215 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) { 216 decaps = 1; 217 break; 218 } 219 220 /* 221 * We need the inner address. However, we only get here for 222 * transport mode so the outer address is identical. 223 */ 224 daddr = &x->id.daddr; 225 family = x->outer_mode->afinfo->family; 226 227 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq); 228 if (err < 0) { 229 XFRM_INC_STATS(LINUX_MIB_XFRMINHDRERROR); 230 goto drop; 231 } 232 } while (!err); 233 234 nf_reset(skb); 235 236 if (decaps) { 237 dst_release(skb->dst); 238 skb->dst = NULL; 239 netif_rx(skb); 240 return 0; 241 } else { 242 return x->inner_mode->afinfo->transport_finish(skb, async); 243 } 244 245 drop_unlock: 246 spin_unlock(&x->lock); 247 drop: 248 kfree_skb(skb); 249 return 0; 250 } 251 EXPORT_SYMBOL(xfrm_input); 252 253 int xfrm_input_resume(struct sk_buff *skb, int nexthdr) 254 { 255 return xfrm_input(skb, nexthdr, 0, -1); 256 } 257 EXPORT_SYMBOL(xfrm_input_resume); 258 259 void __init xfrm_input_init(void) 260 { 261 secpath_cachep = kmem_cache_create("secpath_cache", 262 sizeof(struct sec_path), 263 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, 264 NULL); 265 } 266