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 skb; 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 const 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 err_free_skb; 148 } 149 150 tun_key = &OVS_CB(skb)->egress_tun_info->tunnel; 151 rt = ovs_tunnel_route_lookup(net, tun_key, skb->mark, &fl, IPPROTO_GRE); 152 if (IS_ERR(rt)) { 153 err = PTR_ERR(rt); 154 goto err_free_skb; 155 } 156 157 tunnel_hlen = ip_gre_calc_hlen(tun_key->tun_flags); 158 159 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len 160 + tunnel_hlen + sizeof(struct iphdr) 161 + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0); 162 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { 163 int head_delta = SKB_DATA_ALIGN(min_headroom - 164 skb_headroom(skb) + 165 16); 166 err = pskb_expand_head(skb, max_t(int, head_delta, 0), 167 0, GFP_ATOMIC); 168 if (unlikely(err)) 169 goto err_free_rt; 170 } 171 172 skb = vlan_hwaccel_push_inside(skb); 173 if (unlikely(!skb)) { 174 err = -ENOMEM; 175 goto err_free_rt; 176 } 177 178 /* Push Tunnel header. */ 179 skb = __build_header(skb, tunnel_hlen); 180 if (IS_ERR(skb)) { 181 err = PTR_ERR(skb); 182 skb = NULL; 183 goto err_free_rt; 184 } 185 186 df = tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? 187 htons(IP_DF) : 0; 188 189 skb->ignore_df = 1; 190 191 return iptunnel_xmit(skb->sk, rt, skb, fl.saddr, 192 tun_key->ipv4_dst, IPPROTO_GRE, 193 tun_key->ipv4_tos, tun_key->ipv4_ttl, df, false); 194 err_free_rt: 195 ip_rt_put(rt); 196 err_free_skb: 197 kfree_skb(skb); 198 return err; 199 } 200 201 static struct gre_cisco_protocol gre_protocol = { 202 .handler = gre_rcv, 203 .err_handler = gre_err, 204 .priority = 1, 205 }; 206 207 static int gre_ports; 208 static int gre_init(void) 209 { 210 int err; 211 212 gre_ports++; 213 if (gre_ports > 1) 214 return 0; 215 216 err = gre_cisco_register(&gre_protocol); 217 if (err) 218 pr_warn("cannot register gre protocol handler\n"); 219 220 return err; 221 } 222 223 static void gre_exit(void) 224 { 225 gre_ports--; 226 if (gre_ports > 0) 227 return; 228 229 gre_cisco_unregister(&gre_protocol); 230 } 231 232 static const char *gre_get_name(const struct vport *vport) 233 { 234 return vport_priv(vport); 235 } 236 237 static struct vport *gre_create(const struct vport_parms *parms) 238 { 239 struct net *net = ovs_dp_get_net(parms->dp); 240 struct ovs_net *ovs_net; 241 struct vport *vport; 242 int err; 243 244 err = gre_init(); 245 if (err) 246 return ERR_PTR(err); 247 248 ovs_net = net_generic(net, ovs_net_id); 249 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) { 250 vport = ERR_PTR(-EEXIST); 251 goto error; 252 } 253 254 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms); 255 if (IS_ERR(vport)) 256 goto error; 257 258 strncpy(vport_priv(vport), parms->name, IFNAMSIZ); 259 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport); 260 return vport; 261 262 error: 263 gre_exit(); 264 return vport; 265 } 266 267 static void gre_tnl_destroy(struct vport *vport) 268 { 269 struct net *net = ovs_dp_get_net(vport->dp); 270 struct ovs_net *ovs_net; 271 272 ovs_net = net_generic(net, ovs_net_id); 273 274 RCU_INIT_POINTER(ovs_net->vport_net.gre_vport, NULL); 275 ovs_vport_deferred_free(vport); 276 gre_exit(); 277 } 278 279 static int gre_get_egress_tun_info(struct vport *vport, struct sk_buff *skb, 280 struct ovs_tunnel_info *egress_tun_info) 281 { 282 return ovs_tunnel_get_egress_info(egress_tun_info, 283 ovs_dp_get_net(vport->dp), 284 OVS_CB(skb)->egress_tun_info, 285 IPPROTO_GRE, skb->mark, 0, 0); 286 } 287 288 static struct vport_ops ovs_gre_vport_ops = { 289 .type = OVS_VPORT_TYPE_GRE, 290 .create = gre_create, 291 .destroy = gre_tnl_destroy, 292 .get_name = gre_get_name, 293 .send = gre_tnl_send, 294 .get_egress_tun_info = gre_get_egress_tun_info, 295 .owner = THIS_MODULE, 296 }; 297 298 static int __init ovs_gre_tnl_init(void) 299 { 300 return ovs_vport_ops_register(&ovs_gre_vport_ops); 301 } 302 303 static void __exit ovs_gre_tnl_exit(void) 304 { 305 ovs_vport_ops_unregister(&ovs_gre_vport_ops); 306 } 307 308 module_init(ovs_gre_tnl_init); 309 module_exit(ovs_gre_tnl_exit); 310 311 MODULE_DESCRIPTION("OVS: GRE switching port"); 312 MODULE_LICENSE("GPL"); 313 MODULE_ALIAS("vport-type-3"); 314