| 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 | EXPORT_SYMBOL(xfrm_parse_spi); |
| 85 | |
| 86 | int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb) |
| 87 | { |
| 88 | int err; |
| 89 | |
| 90 | err = x->outer_mode->afinfo->extract_input(x, skb); |
| 91 | if (err) |
| 92 | return err; |
| 93 | |
| 94 | skb->protocol = x->inner_mode->afinfo->eth_proto; |
| 95 | return x->inner_mode->input2(x, skb); |
| 96 | } |
| 97 | EXPORT_SYMBOL(xfrm_prepare_input); |
| 98 | |
| 99 | int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) |
| 100 | { |
| 101 | int err; |
| 102 | __be32 seq; |
| 103 | struct xfrm_state *x; |
| 104 | int decaps = 0; |
| 105 | unsigned int daddroff = XFRM_SPI_SKB_CB(skb)->daddroff; |
| 106 | |
| 107 | /* Allocate new secpath or COW existing one. */ |
| 108 | if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { |
| 109 | struct sec_path *sp; |
| 110 | |
| 111 | sp = secpath_dup(skb->sp); |
| 112 | if (!sp) |
| 113 | goto drop; |
| 114 | if (skb->sp) |
| 115 | secpath_put(skb->sp); |
| 116 | skb->sp = sp; |
| 117 | } |
| 118 | |
| 119 | seq = 0; |
| 120 | if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) |
| 121 | goto drop; |
| 122 | |
| 123 | do { |
| 124 | if (skb->sp->len == XFRM_MAX_DEPTH) |
| 125 | goto drop; |
| 126 | |
| 127 | x = xfrm_state_lookup((xfrm_address_t *) |
| 128 | (skb_network_header(skb) + daddroff), |
| 129 | spi, nexthdr, AF_INET); |
| 130 | if (x == NULL) |
| 131 | goto drop; |
| 132 | |
| 133 | skb->sp->xvec[skb->sp->len++] = x; |
| 134 | |
| 135 | spin_lock(&x->lock); |
| 136 | if (unlikely(x->km.state != XFRM_STATE_VALID)) |
| 137 | goto drop_unlock; |
| 138 | |
| 139 | if ((x->encap ? x->encap->encap_type : 0) != encap_type) |
| 140 | goto drop_unlock; |
| 141 | |
| 142 | if (x->props.replay_window && xfrm_replay_check(x, seq)) |
| 143 | goto drop_unlock; |
| 144 | |
| 145 | if (xfrm_state_check_expire(x)) |
| 146 | goto drop_unlock; |
| 147 | |
| 148 | spin_unlock(&x->lock); |
| 149 | |
| 150 | nexthdr = x->type->input(x, skb); |
| 151 | |
| 152 | spin_lock(&x->lock); |
| 153 | if (nexthdr <= 0) { |
| 154 | if (nexthdr == -EBADMSG) |
| 155 | x->stats.integrity_failed++; |
| 156 | goto drop_unlock; |
| 157 | } |
| 158 | |
| 159 | /* only the first xfrm gets the encap type */ |
| 160 | encap_type = 0; |
| 161 | |
| 162 | if (x->props.replay_window) |
| 163 | xfrm_replay_advance(x, seq); |
| 164 | |
| 165 | x->curlft.bytes += skb->len; |
| 166 | x->curlft.packets++; |
| 167 | |
| 168 | spin_unlock(&x->lock); |
| 169 | |
| 170 | XFRM_MODE_SKB_CB(skb)->protocol = nexthdr; |
| 171 | |
| 172 | if (x->inner_mode->input(x, skb)) |
| 173 | goto drop; |
| 174 | |
| 175 | if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) { |
| 176 | decaps = 1; |
| 177 | break; |
| 178 | } |
| 179 | |
| 180 | err = xfrm_parse_spi(skb, nexthdr, &spi, &seq); |
| 181 | if (err < 0) |
| 182 | goto drop; |
| 183 | } while (!err); |
| 184 | |
| 185 | nf_reset(skb); |
| 186 | |
| 187 | if (decaps) { |
| 188 | dst_release(skb->dst); |
| 189 | skb->dst = NULL; |
| 190 | netif_rx(skb); |
| 191 | return 0; |
| 192 | } else { |
| 193 | return x->inner_mode->afinfo->transport_finish(skb, 0); |
| 194 | } |
| 195 | |
| 196 | drop_unlock: |
| 197 | spin_unlock(&x->lock); |
| 198 | drop: |
| 199 | kfree_skb(skb); |
| 200 | return 0; |
| 201 | } |
| 202 | EXPORT_SYMBOL(xfrm_input); |
| 203 | |
| 204 | void __init xfrm_input_init(void) |
| 205 | { |
| 206 | secpath_cachep = kmem_cache_create("secpath_cache", |
| 207 | sizeof(struct sec_path), |
| 208 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, |
| 209 | NULL); |
| 210 | } |