| 1 | /* |
| 2 | * xfrm4_policy.c |
| 3 | * |
| 4 | * Changes: |
| 5 | * Kazunori MIYAZAWA @USAGI |
| 6 | * YOSHIFUJI Hideaki @USAGI |
| 7 | * Split up af-specific portion |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/err.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/inetdevice.h> |
| 14 | #include <net/dst.h> |
| 15 | #include <net/xfrm.h> |
| 16 | #include <net/ip.h> |
| 17 | |
| 18 | static struct xfrm_policy_afinfo xfrm4_policy_afinfo; |
| 19 | |
| 20 | static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, |
| 21 | xfrm_address_t *saddr, |
| 22 | xfrm_address_t *daddr) |
| 23 | { |
| 24 | struct flowi fl = { |
| 25 | .nl_u = { |
| 26 | .ip4_u = { |
| 27 | .tos = tos, |
| 28 | .daddr = daddr->a4, |
| 29 | }, |
| 30 | }, |
| 31 | }; |
| 32 | struct dst_entry *dst; |
| 33 | struct rtable *rt; |
| 34 | int err; |
| 35 | |
| 36 | if (saddr) |
| 37 | fl.fl4_src = saddr->a4; |
| 38 | |
| 39 | err = __ip_route_output_key(net, &rt, &fl); |
| 40 | dst = &rt->dst; |
| 41 | if (err) |
| 42 | dst = ERR_PTR(err); |
| 43 | return dst; |
| 44 | } |
| 45 | |
| 46 | static int xfrm4_get_saddr(struct net *net, |
| 47 | xfrm_address_t *saddr, xfrm_address_t *daddr) |
| 48 | { |
| 49 | struct dst_entry *dst; |
| 50 | struct rtable *rt; |
| 51 | |
| 52 | dst = xfrm4_dst_lookup(net, 0, NULL, daddr); |
| 53 | if (IS_ERR(dst)) |
| 54 | return -EHOSTUNREACH; |
| 55 | |
| 56 | rt = (struct rtable *)dst; |
| 57 | saddr->a4 = rt->rt_src; |
| 58 | dst_release(dst); |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | static int xfrm4_get_tos(struct flowi *fl) |
| 63 | { |
| 64 | return IPTOS_RT_MASK & fl->fl4_tos; /* Strip ECN bits */ |
| 65 | } |
| 66 | |
| 67 | static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, |
| 68 | int nfheader_len) |
| 69 | { |
| 70 | return 0; |
| 71 | } |
| 72 | |
| 73 | static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, |
| 74 | struct flowi *fl) |
| 75 | { |
| 76 | struct rtable *rt = (struct rtable *)xdst->route; |
| 77 | |
| 78 | xdst->u.rt.fl = *fl; |
| 79 | |
| 80 | xdst->u.dst.dev = dev; |
| 81 | dev_hold(dev); |
| 82 | |
| 83 | xdst->u.rt.peer = rt->peer; |
| 84 | if (rt->peer) |
| 85 | atomic_inc(&rt->peer->refcnt); |
| 86 | |
| 87 | /* Sheit... I remember I did this right. Apparently, |
| 88 | * it was magically lost, so this code needs audit */ |
| 89 | xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | |
| 90 | RTCF_LOCAL); |
| 91 | xdst->u.rt.rt_type = rt->rt_type; |
| 92 | xdst->u.rt.rt_src = rt->rt_src; |
| 93 | xdst->u.rt.rt_dst = rt->rt_dst; |
| 94 | xdst->u.rt.rt_gateway = rt->rt_gateway; |
| 95 | xdst->u.rt.rt_spec_dst = rt->rt_spec_dst; |
| 96 | |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | static void |
| 101 | _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) |
| 102 | { |
| 103 | struct iphdr *iph = ip_hdr(skb); |
| 104 | u8 *xprth = skb_network_header(skb) + iph->ihl * 4; |
| 105 | |
| 106 | memset(fl, 0, sizeof(struct flowi)); |
| 107 | fl->mark = skb->mark; |
| 108 | |
| 109 | if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { |
| 110 | switch (iph->protocol) { |
| 111 | case IPPROTO_UDP: |
| 112 | case IPPROTO_UDPLITE: |
| 113 | case IPPROTO_TCP: |
| 114 | case IPPROTO_SCTP: |
| 115 | case IPPROTO_DCCP: |
| 116 | if (xprth + 4 < skb->data || |
| 117 | pskb_may_pull(skb, xprth + 4 - skb->data)) { |
| 118 | __be16 *ports = (__be16 *)xprth; |
| 119 | |
| 120 | fl->fl_ip_sport = ports[!!reverse]; |
| 121 | fl->fl_ip_dport = ports[!reverse]; |
| 122 | } |
| 123 | break; |
| 124 | |
| 125 | case IPPROTO_ICMP: |
| 126 | if (pskb_may_pull(skb, xprth + 2 - skb->data)) { |
| 127 | u8 *icmp = xprth; |
| 128 | |
| 129 | fl->fl_icmp_type = icmp[0]; |
| 130 | fl->fl_icmp_code = icmp[1]; |
| 131 | } |
| 132 | break; |
| 133 | |
| 134 | case IPPROTO_ESP: |
| 135 | if (pskb_may_pull(skb, xprth + 4 - skb->data)) { |
| 136 | __be32 *ehdr = (__be32 *)xprth; |
| 137 | |
| 138 | fl->fl_ipsec_spi = ehdr[0]; |
| 139 | } |
| 140 | break; |
| 141 | |
| 142 | case IPPROTO_AH: |
| 143 | if (pskb_may_pull(skb, xprth + 8 - skb->data)) { |
| 144 | __be32 *ah_hdr = (__be32*)xprth; |
| 145 | |
| 146 | fl->fl_ipsec_spi = ah_hdr[1]; |
| 147 | } |
| 148 | break; |
| 149 | |
| 150 | case IPPROTO_COMP: |
| 151 | if (pskb_may_pull(skb, xprth + 4 - skb->data)) { |
| 152 | __be16 *ipcomp_hdr = (__be16 *)xprth; |
| 153 | |
| 154 | fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); |
| 155 | } |
| 156 | break; |
| 157 | default: |
| 158 | fl->fl_ipsec_spi = 0; |
| 159 | break; |
| 160 | } |
| 161 | } |
| 162 | fl->proto = iph->protocol; |
| 163 | fl->fl4_dst = reverse ? iph->saddr : iph->daddr; |
| 164 | fl->fl4_src = reverse ? iph->daddr : iph->saddr; |
| 165 | fl->fl4_tos = iph->tos; |
| 166 | } |
| 167 | |
| 168 | static inline int xfrm4_garbage_collect(struct dst_ops *ops) |
| 169 | { |
| 170 | struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); |
| 171 | |
| 172 | xfrm4_policy_afinfo.garbage_collect(net); |
| 173 | return (dst_entries_get_slow(ops) > ops->gc_thresh * 2); |
| 174 | } |
| 175 | |
| 176 | static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) |
| 177 | { |
| 178 | struct xfrm_dst *xdst = (struct xfrm_dst *)dst; |
| 179 | struct dst_entry *path = xdst->route; |
| 180 | |
| 181 | path->ops->update_pmtu(path, mtu); |
| 182 | } |
| 183 | |
| 184 | static void xfrm4_dst_destroy(struct dst_entry *dst) |
| 185 | { |
| 186 | struct xfrm_dst *xdst = (struct xfrm_dst *)dst; |
| 187 | |
| 188 | if (likely(xdst->u.rt.peer)) |
| 189 | inet_putpeer(xdst->u.rt.peer); |
| 190 | xfrm_dst_destroy(xdst); |
| 191 | } |
| 192 | |
| 193 | static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, |
| 194 | int unregister) |
| 195 | { |
| 196 | if (!unregister) |
| 197 | return; |
| 198 | |
| 199 | xfrm_dst_ifdown(dst, dev); |
| 200 | } |
| 201 | |
| 202 | static struct dst_ops xfrm4_dst_ops = { |
| 203 | .family = AF_INET, |
| 204 | .protocol = cpu_to_be16(ETH_P_IP), |
| 205 | .gc = xfrm4_garbage_collect, |
| 206 | .update_pmtu = xfrm4_update_pmtu, |
| 207 | .destroy = xfrm4_dst_destroy, |
| 208 | .ifdown = xfrm4_dst_ifdown, |
| 209 | .local_out = __ip_local_out, |
| 210 | .gc_thresh = 1024, |
| 211 | }; |
| 212 | |
| 213 | static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { |
| 214 | .family = AF_INET, |
| 215 | .dst_ops = &xfrm4_dst_ops, |
| 216 | .dst_lookup = xfrm4_dst_lookup, |
| 217 | .get_saddr = xfrm4_get_saddr, |
| 218 | .decode_session = _decode_session4, |
| 219 | .get_tos = xfrm4_get_tos, |
| 220 | .init_path = xfrm4_init_path, |
| 221 | .fill_dst = xfrm4_fill_dst, |
| 222 | }; |
| 223 | |
| 224 | #ifdef CONFIG_SYSCTL |
| 225 | static struct ctl_table xfrm4_policy_table[] = { |
| 226 | { |
| 227 | .procname = "xfrm4_gc_thresh", |
| 228 | .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, |
| 229 | .maxlen = sizeof(int), |
| 230 | .mode = 0644, |
| 231 | .proc_handler = proc_dointvec, |
| 232 | }, |
| 233 | { } |
| 234 | }; |
| 235 | |
| 236 | static struct ctl_table_header *sysctl_hdr; |
| 237 | #endif |
| 238 | |
| 239 | static void __init xfrm4_policy_init(void) |
| 240 | { |
| 241 | xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); |
| 242 | } |
| 243 | |
| 244 | static void __exit xfrm4_policy_fini(void) |
| 245 | { |
| 246 | #ifdef CONFIG_SYSCTL |
| 247 | if (sysctl_hdr) |
| 248 | unregister_net_sysctl_table(sysctl_hdr); |
| 249 | #endif |
| 250 | xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); |
| 251 | } |
| 252 | |
| 253 | void __init xfrm4_init(int rt_max_size) |
| 254 | { |
| 255 | /* |
| 256 | * Select a default value for the gc_thresh based on the main route |
| 257 | * table hash size. It seems to me the worst case scenario is when |
| 258 | * we have ipsec operating in transport mode, in which we create a |
| 259 | * dst_entry per socket. The xfrm gc algorithm starts trying to remove |
| 260 | * entries at gc_thresh, and prevents new allocations as 2*gc_thresh |
| 261 | * so lets set an initial xfrm gc_thresh value at the rt_max_size/2. |
| 262 | * That will let us store an ipsec connection per route table entry, |
| 263 | * and start cleaning when were 1/2 full |
| 264 | */ |
| 265 | xfrm4_dst_ops.gc_thresh = rt_max_size/2; |
| 266 | dst_entries_init(&xfrm4_dst_ops); |
| 267 | |
| 268 | xfrm4_state_init(); |
| 269 | xfrm4_policy_init(); |
| 270 | #ifdef CONFIG_SYSCTL |
| 271 | sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path, |
| 272 | xfrm4_policy_table); |
| 273 | #endif |
| 274 | } |
| 275 | |