1 /* 2 * Copyright (c) 2007-2014 Nicira, Inc. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of version 2 of the GNU General Public 6 * License as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 16 * 02110-1301, USA 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/if.h> 22 #include <linux/skbuff.h> 23 #include <linux/ip.h> 24 #include <linux/if_tunnel.h> 25 #include <linux/if_vlan.h> 26 #include <linux/in.h> 27 #include <linux/in_route.h> 28 #include <linux/inetdevice.h> 29 #include <linux/jhash.h> 30 #include <linux/list.h> 31 #include <linux/kernel.h> 32 #include <linux/module.h> 33 #include <linux/workqueue.h> 34 #include <linux/rculist.h> 35 #include <net/route.h> 36 #include <net/xfrm.h> 37 38 #include <net/icmp.h> 39 #include <net/ip.h> 40 #include <net/ip_tunnels.h> 41 #include <net/gre.h> 42 #include <net/net_namespace.h> 43 #include <net/netns/generic.h> 44 #include <net/protocol.h> 45 46 #include "datapath.h" 47 #include "vport.h" 48 49 static struct vport_ops ovs_gre_vport_ops; 50 51 /* Returns the least-significant 32 bits of a __be64. */ 52 static __be32 be64_get_low32(__be64 x) 53 { 54 #ifdef __BIG_ENDIAN 55 return (__force __be32)x; 56 #else 57 return (__force __be32)((__force u64)x >> 32); 58 #endif 59 } 60 61 static __be16 filter_tnl_flags(__be16 flags) 62 { 63 return flags & (TUNNEL_CSUM | TUNNEL_KEY); 64 } 65 66 static struct sk_buff *__build_header(struct sk_buff *skb, 67 int tunnel_hlen) 68 { 69 struct tnl_ptk_info tpi; 70 const struct ovs_key_ipv4_tunnel *tun_key; 71 72 tun_key = &OVS_CB(skb)->egress_tun_info->tunnel; 73 74 skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM)); 75 if (IS_ERR(skb)) 76 return NULL; 77 78 tpi.flags = filter_tnl_flags(tun_key->tun_flags); 79 tpi.proto = htons(ETH_P_TEB); 80 tpi.key = be64_get_low32(tun_key->tun_id); 81 tpi.seq = 0; 82 gre_build_header(skb, &tpi, tunnel_hlen); 83 84 return skb; 85 } 86 87 static __be64 key_to_tunnel_id(__be32 key, __be32 seq) 88 { 89 #ifdef __BIG_ENDIAN 90 return (__force __be64)((__force u64)seq << 32 | (__force u32)key); 91 #else 92 return (__force __be64)((__force u64)key << 32 | (__force u32)seq); 93 #endif 94 } 95 96 /* Called with rcu_read_lock and BH disabled. */ 97 static int gre_rcv(struct sk_buff *skb, 98 const struct tnl_ptk_info *tpi) 99 { 100 struct ovs_tunnel_info tun_info; 101 struct ovs_net *ovs_net; 102 struct vport *vport; 103 __be64 key; 104 105 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 106 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 107 if (unlikely(!vport)) 108 return PACKET_REJECT; 109 110 key = key_to_tunnel_id(tpi->key, tpi->seq); 111 ovs_flow_tun_info_init(&tun_info, ip_hdr(skb), 0, 0, key, 112 filter_tnl_flags(tpi->flags), NULL, 0); 113 114 ovs_vport_receive(vport, skb, &tun_info); 115 return PACKET_RCVD; 116 } 117 118 /* Called with rcu_read_lock and BH disabled. */ 119 static int gre_err(struct sk_buff *skb, u32 info, 120 const struct tnl_ptk_info *tpi) 121 { 122 struct ovs_net *ovs_net; 123 struct vport *vport; 124 125 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 126 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 127 128 if (unlikely(!vport)) 129 return PACKET_REJECT; 130 else 131 return PACKET_RCVD; 132 } 133 134 static int gre_tnl_send(struct vport *vport, struct sk_buff *skb) 135 { 136 struct net *net = ovs_dp_get_net(vport->dp); 137 struct ovs_key_ipv4_tunnel *tun_key; 138 struct flowi4 fl; 139 struct rtable *rt; 140 int min_headroom; 141 int tunnel_hlen; 142 __be16 df; 143 int err; 144 145 if (unlikely(!OVS_CB(skb)->egress_tun_info)) { 146 err = -EINVAL; 147 goto error; 148 } 149 150 tun_key = &OVS_CB(skb)->egress_tun_info->tunnel; 151 /* Route lookup */ 152 memset(&fl, 0, sizeof(fl)); 153 fl.daddr = tun_key->ipv4_dst; 154 fl.saddr = tun_key->ipv4_src; 155 fl.flowi4_tos = RT_TOS(tun_key->ipv4_tos); 156 fl.flowi4_mark = skb->mark; 157 fl.flowi4_proto = IPPROTO_GRE; 158 159 rt = ip_route_output_key(net, &fl); 160 if (IS_ERR(rt)) 161 return PTR_ERR(rt); 162 163 tunnel_hlen = ip_gre_calc_hlen(tun_key->tun_flags); 164 165 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len 166 + tunnel_hlen + sizeof(struct iphdr) 167 + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0); 168 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { 169 int head_delta = SKB_DATA_ALIGN(min_headroom - 170 skb_headroom(skb) + 171 16); 172 err = pskb_expand_head(skb, max_t(int, head_delta, 0), 173 0, GFP_ATOMIC); 174 if (unlikely(err)) 175 goto err_free_rt; 176 } 177 178 skb = vlan_hwaccel_push_inside(skb); 179 if (unlikely(!skb)) { 180 err = -ENOMEM; 181 goto err_free_rt; 182 } 183 184 /* Push Tunnel header. */ 185 skb = __build_header(skb, tunnel_hlen); 186 if (unlikely(!skb)) { 187 err = 0; 188 goto err_free_rt; 189 } 190 191 df = tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? 192 htons(IP_DF) : 0; 193 194 skb->ignore_df = 1; 195 196 return iptunnel_xmit(skb->sk, rt, skb, fl.saddr, 197 tun_key->ipv4_dst, IPPROTO_GRE, 198 tun_key->ipv4_tos, tun_key->ipv4_ttl, df, false); 199 err_free_rt: 200 ip_rt_put(rt); 201 error: 202 return err; 203 } 204 205 static struct gre_cisco_protocol gre_protocol = { 206 .handler = gre_rcv, 207 .err_handler = gre_err, 208 .priority = 1, 209 }; 210 211 static int gre_ports; 212 static int gre_init(void) 213 { 214 int err; 215 216 gre_ports++; 217 if (gre_ports > 1) 218 return 0; 219 220 err = gre_cisco_register(&gre_protocol); 221 if (err) 222 pr_warn("cannot register gre protocol handler\n"); 223 224 return err; 225 } 226 227 static void gre_exit(void) 228 { 229 gre_ports--; 230 if (gre_ports > 0) 231 return; 232 233 gre_cisco_unregister(&gre_protocol); 234 } 235 236 static const char *gre_get_name(const struct vport *vport) 237 { 238 return vport_priv(vport); 239 } 240 241 static struct vport *gre_create(const struct vport_parms *parms) 242 { 243 struct net *net = ovs_dp_get_net(parms->dp); 244 struct ovs_net *ovs_net; 245 struct vport *vport; 246 int err; 247 248 err = gre_init(); 249 if (err) 250 return ERR_PTR(err); 251 252 ovs_net = net_generic(net, ovs_net_id); 253 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) { 254 vport = ERR_PTR(-EEXIST); 255 goto error; 256 } 257 258 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms); 259 if (IS_ERR(vport)) 260 goto error; 261 262 strncpy(vport_priv(vport), parms->name, IFNAMSIZ); 263 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport); 264 return vport; 265 266 error: 267 gre_exit(); 268 return vport; 269 } 270 271 static void gre_tnl_destroy(struct vport *vport) 272 { 273 struct net *net = ovs_dp_get_net(vport->dp); 274 struct ovs_net *ovs_net; 275 276 ovs_net = net_generic(net, ovs_net_id); 277 278 RCU_INIT_POINTER(ovs_net->vport_net.gre_vport, NULL); 279 ovs_vport_deferred_free(vport); 280 gre_exit(); 281 } 282 283 static int gre_get_egress_tun_info(struct vport *vport, struct sk_buff *skb, 284 struct ovs_tunnel_info *egress_tun_info) 285 { 286 return ovs_tunnel_get_egress_info(egress_tun_info, 287 ovs_dp_get_net(vport->dp), 288 OVS_CB(skb)->egress_tun_info, 289 IPPROTO_GRE, skb->mark, 0, 0); 290 } 291 292 static struct vport_ops ovs_gre_vport_ops = { 293 .type = OVS_VPORT_TYPE_GRE, 294 .create = gre_create, 295 .destroy = gre_tnl_destroy, 296 .get_name = gre_get_name, 297 .send = gre_tnl_send, 298 .get_egress_tun_info = gre_get_egress_tun_info, 299 .owner = THIS_MODULE, 300 }; 301 302 static int __init ovs_gre_tnl_init(void) 303 { 304 return ovs_vport_ops_register(&ovs_gre_vport_ops); 305 } 306 307 static void __exit ovs_gre_tnl_exit(void) 308 { 309 ovs_vport_ops_unregister(&ovs_gre_vport_ops); 310 } 311 312 module_init(ovs_gre_tnl_init); 313 module_exit(ovs_gre_tnl_exit); 314 315 MODULE_DESCRIPTION("OVS: GRE switching port"); 316 MODULE_LICENSE("GPL"); 317 MODULE_ALIAS("vport-type-3"); 318