1 /* 2 * Copyright (c) 2007-2013 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/workqueue.h> 33 #include <linux/rculist.h> 34 #include <net/route.h> 35 #include <net/xfrm.h> 36 37 #include <net/icmp.h> 38 #include <net/ip.h> 39 #include <net/ip_tunnels.h> 40 #include <net/gre.h> 41 #include <net/net_namespace.h> 42 #include <net/netns/generic.h> 43 #include <net/protocol.h> 44 45 #include "datapath.h" 46 #include "vport.h" 47 48 /* Returns the least-significant 32 bits of a __be64. */ 49 static __be32 be64_get_low32(__be64 x) 50 { 51 #ifdef __BIG_ENDIAN 52 return (__force __be32)x; 53 #else 54 return (__force __be32)((__force u64)x >> 32); 55 #endif 56 } 57 58 static __be16 filter_tnl_flags(__be16 flags) 59 { 60 return flags & (TUNNEL_CSUM | TUNNEL_KEY); 61 } 62 63 static struct sk_buff *__build_header(struct sk_buff *skb, 64 int tunnel_hlen) 65 { 66 const struct ovs_key_ipv4_tunnel *tun_key = OVS_CB(skb)->tun_key; 67 struct tnl_ptk_info tpi; 68 69 skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM)); 70 if (IS_ERR(skb)) 71 return NULL; 72 73 tpi.flags = filter_tnl_flags(tun_key->tun_flags); 74 tpi.proto = htons(ETH_P_TEB); 75 tpi.key = be64_get_low32(tun_key->tun_id); 76 tpi.seq = 0; 77 gre_build_header(skb, &tpi, tunnel_hlen); 78 79 return skb; 80 } 81 82 static __be64 key_to_tunnel_id(__be32 key, __be32 seq) 83 { 84 #ifdef __BIG_ENDIAN 85 return (__force __be64)((__force u64)seq << 32 | (__force u32)key); 86 #else 87 return (__force __be64)((__force u64)key << 32 | (__force u32)seq); 88 #endif 89 } 90 91 /* Called with rcu_read_lock and BH disabled. */ 92 static int gre_rcv(struct sk_buff *skb, 93 const struct tnl_ptk_info *tpi) 94 { 95 struct ovs_key_ipv4_tunnel tun_key; 96 struct ovs_net *ovs_net; 97 struct vport *vport; 98 __be64 key; 99 100 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 101 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 102 if (unlikely(!vport)) 103 return PACKET_REJECT; 104 105 key = key_to_tunnel_id(tpi->key, tpi->seq); 106 ovs_flow_tun_key_init(&tun_key, ip_hdr(skb), key, 107 filter_tnl_flags(tpi->flags)); 108 109 ovs_vport_receive(vport, skb, &tun_key); 110 return PACKET_RCVD; 111 } 112 113 /* Called with rcu_read_lock and BH disabled. */ 114 static int gre_err(struct sk_buff *skb, u32 info, 115 const struct tnl_ptk_info *tpi) 116 { 117 struct ovs_net *ovs_net; 118 struct vport *vport; 119 120 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 121 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 122 123 if (unlikely(!vport)) 124 return PACKET_REJECT; 125 else 126 return PACKET_RCVD; 127 } 128 129 static int gre_tnl_send(struct vport *vport, struct sk_buff *skb) 130 { 131 struct net *net = ovs_dp_get_net(vport->dp); 132 struct flowi4 fl; 133 struct rtable *rt; 134 int min_headroom; 135 int tunnel_hlen; 136 __be16 df; 137 int err; 138 139 if (unlikely(!OVS_CB(skb)->tun_key)) { 140 err = -EINVAL; 141 goto error; 142 } 143 144 /* Route lookup */ 145 memset(&fl, 0, sizeof(fl)); 146 fl.daddr = OVS_CB(skb)->tun_key->ipv4_dst; 147 fl.saddr = OVS_CB(skb)->tun_key->ipv4_src; 148 fl.flowi4_tos = RT_TOS(OVS_CB(skb)->tun_key->ipv4_tos); 149 fl.flowi4_mark = skb->mark; 150 fl.flowi4_proto = IPPROTO_GRE; 151 152 rt = ip_route_output_key(net, &fl); 153 if (IS_ERR(rt)) 154 return PTR_ERR(rt); 155 156 tunnel_hlen = ip_gre_calc_hlen(OVS_CB(skb)->tun_key->tun_flags); 157 158 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len 159 + tunnel_hlen + sizeof(struct iphdr) 160 + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0); 161 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { 162 int head_delta = SKB_DATA_ALIGN(min_headroom - 163 skb_headroom(skb) + 164 16); 165 err = pskb_expand_head(skb, max_t(int, head_delta, 0), 166 0, GFP_ATOMIC); 167 if (unlikely(err)) 168 goto err_free_rt; 169 } 170 171 if (vlan_tx_tag_present(skb)) { 172 if (unlikely(!__vlan_put_tag(skb, 173 skb->vlan_proto, 174 vlan_tx_tag_get(skb)))) { 175 err = -ENOMEM; 176 goto err_free_rt; 177 } 178 skb->vlan_tci = 0; 179 } 180 181 /* Push Tunnel header. */ 182 skb = __build_header(skb, tunnel_hlen); 183 if (unlikely(!skb)) { 184 err = 0; 185 goto err_free_rt; 186 } 187 188 df = OVS_CB(skb)->tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? 189 htons(IP_DF) : 0; 190 191 skb->ignore_df = 1; 192 193 return iptunnel_xmit(skb->sk, rt, skb, fl.saddr, 194 OVS_CB(skb)->tun_key->ipv4_dst, IPPROTO_GRE, 195 OVS_CB(skb)->tun_key->ipv4_tos, 196 OVS_CB(skb)->tun_key->ipv4_ttl, df, false); 197 err_free_rt: 198 ip_rt_put(rt); 199 error: 200 return err; 201 } 202 203 static struct gre_cisco_protocol gre_protocol = { 204 .handler = gre_rcv, 205 .err_handler = gre_err, 206 .priority = 1, 207 }; 208 209 static int gre_ports; 210 static int gre_init(void) 211 { 212 int err; 213 214 gre_ports++; 215 if (gre_ports > 1) 216 return 0; 217 218 err = gre_cisco_register(&gre_protocol); 219 if (err) 220 pr_warn("cannot register gre protocol handler\n"); 221 222 return err; 223 } 224 225 static void gre_exit(void) 226 { 227 gre_ports--; 228 if (gre_ports > 0) 229 return; 230 231 gre_cisco_unregister(&gre_protocol); 232 } 233 234 static const char *gre_get_name(const struct vport *vport) 235 { 236 return vport_priv(vport); 237 } 238 239 static struct vport *gre_create(const struct vport_parms *parms) 240 { 241 struct net *net = ovs_dp_get_net(parms->dp); 242 struct ovs_net *ovs_net; 243 struct vport *vport; 244 int err; 245 246 err = gre_init(); 247 if (err) 248 return ERR_PTR(err); 249 250 ovs_net = net_generic(net, ovs_net_id); 251 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) { 252 vport = ERR_PTR(-EEXIST); 253 goto error; 254 } 255 256 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms); 257 if (IS_ERR(vport)) 258 goto error; 259 260 strncpy(vport_priv(vport), parms->name, IFNAMSIZ); 261 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport); 262 return vport; 263 264 error: 265 gre_exit(); 266 return vport; 267 } 268 269 static void gre_tnl_destroy(struct vport *vport) 270 { 271 struct net *net = ovs_dp_get_net(vport->dp); 272 struct ovs_net *ovs_net; 273 274 ovs_net = net_generic(net, ovs_net_id); 275 276 RCU_INIT_POINTER(ovs_net->vport_net.gre_vport, NULL); 277 ovs_vport_deferred_free(vport); 278 gre_exit(); 279 } 280 281 const struct vport_ops ovs_gre_vport_ops = { 282 .type = OVS_VPORT_TYPE_GRE, 283 .create = gre_create, 284 .destroy = gre_tnl_destroy, 285 .get_name = gre_get_name, 286 .send = gre_tnl_send, 287 }; 288