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/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 struct tnl_ptk_info tpi; 67 const struct ovs_key_ipv4_tunnel *tun_key; 68 69 tun_key = &OVS_CB(skb)->egress_tun_info->tunnel; 70 71 skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM)); 72 if (IS_ERR(skb)) 73 return NULL; 74 75 tpi.flags = filter_tnl_flags(tun_key->tun_flags); 76 tpi.proto = htons(ETH_P_TEB); 77 tpi.key = be64_get_low32(tun_key->tun_id); 78 tpi.seq = 0; 79 gre_build_header(skb, &tpi, tunnel_hlen); 80 81 return skb; 82 } 83 84 static __be64 key_to_tunnel_id(__be32 key, __be32 seq) 85 { 86 #ifdef __BIG_ENDIAN 87 return (__force __be64)((__force u64)seq << 32 | (__force u32)key); 88 #else 89 return (__force __be64)((__force u64)key << 32 | (__force u32)seq); 90 #endif 91 } 92 93 /* Called with rcu_read_lock and BH disabled. */ 94 static int gre_rcv(struct sk_buff *skb, 95 const struct tnl_ptk_info *tpi) 96 { 97 struct ovs_tunnel_info tun_info; 98 struct ovs_net *ovs_net; 99 struct vport *vport; 100 __be64 key; 101 102 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 103 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 104 if (unlikely(!vport)) 105 return PACKET_REJECT; 106 107 key = key_to_tunnel_id(tpi->key, tpi->seq); 108 ovs_flow_tun_info_init(&tun_info, ip_hdr(skb), key, 109 filter_tnl_flags(tpi->flags), NULL, 0); 110 111 ovs_vport_receive(vport, skb, &tun_info); 112 return PACKET_RCVD; 113 } 114 115 /* Called with rcu_read_lock and BH disabled. */ 116 static int gre_err(struct sk_buff *skb, u32 info, 117 const struct tnl_ptk_info *tpi) 118 { 119 struct ovs_net *ovs_net; 120 struct vport *vport; 121 122 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id); 123 vport = rcu_dereference(ovs_net->vport_net.gre_vport); 124 125 if (unlikely(!vport)) 126 return PACKET_REJECT; 127 else 128 return PACKET_RCVD; 129 } 130 131 static int gre_tnl_send(struct vport *vport, struct sk_buff *skb) 132 { 133 struct net *net = ovs_dp_get_net(vport->dp); 134 struct ovs_key_ipv4_tunnel *tun_key; 135 struct flowi4 fl; 136 struct rtable *rt; 137 int min_headroom; 138 int tunnel_hlen; 139 __be16 df; 140 int err; 141 142 if (unlikely(!OVS_CB(skb)->egress_tun_info)) { 143 err = -EINVAL; 144 goto error; 145 } 146 147 tun_key = &OVS_CB(skb)->egress_tun_info->tunnel; 148 /* Route lookup */ 149 memset(&fl, 0, sizeof(fl)); 150 fl.daddr = tun_key->ipv4_dst; 151 fl.saddr = tun_key->ipv4_src; 152 fl.flowi4_tos = RT_TOS(tun_key->ipv4_tos); 153 fl.flowi4_mark = skb->mark; 154 fl.flowi4_proto = IPPROTO_GRE; 155 156 rt = ip_route_output_key(net, &fl); 157 if (IS_ERR(rt)) 158 return PTR_ERR(rt); 159 160 tunnel_hlen = ip_gre_calc_hlen(tun_key->tun_flags); 161 162 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len 163 + tunnel_hlen + sizeof(struct iphdr) 164 + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0); 165 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { 166 int head_delta = SKB_DATA_ALIGN(min_headroom - 167 skb_headroom(skb) + 168 16); 169 err = pskb_expand_head(skb, max_t(int, head_delta, 0), 170 0, GFP_ATOMIC); 171 if (unlikely(err)) 172 goto err_free_rt; 173 } 174 175 if (vlan_tx_tag_present(skb)) { 176 if (unlikely(!__vlan_put_tag(skb, 177 skb->vlan_proto, 178 vlan_tx_tag_get(skb)))) { 179 err = -ENOMEM; 180 goto err_free_rt; 181 } 182 skb->vlan_tci = 0; 183 } 184 185 /* Push Tunnel header. */ 186 skb = __build_header(skb, tunnel_hlen); 187 if (unlikely(!skb)) { 188 err = 0; 189 goto err_free_rt; 190 } 191 192 df = tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? 193 htons(IP_DF) : 0; 194 195 skb->ignore_df = 1; 196 197 return iptunnel_xmit(skb->sk, rt, skb, fl.saddr, 198 tun_key->ipv4_dst, IPPROTO_GRE, 199 tun_key->ipv4_tos, tun_key->ipv4_ttl, df, false); 200 err_free_rt: 201 ip_rt_put(rt); 202 error: 203 return err; 204 } 205 206 static struct gre_cisco_protocol gre_protocol = { 207 .handler = gre_rcv, 208 .err_handler = gre_err, 209 .priority = 1, 210 }; 211 212 static int gre_ports; 213 static int gre_init(void) 214 { 215 int err; 216 217 gre_ports++; 218 if (gre_ports > 1) 219 return 0; 220 221 err = gre_cisco_register(&gre_protocol); 222 if (err) 223 pr_warn("cannot register gre protocol handler\n"); 224 225 return err; 226 } 227 228 static void gre_exit(void) 229 { 230 gre_ports--; 231 if (gre_ports > 0) 232 return; 233 234 gre_cisco_unregister(&gre_protocol); 235 } 236 237 static const char *gre_get_name(const struct vport *vport) 238 { 239 return vport_priv(vport); 240 } 241 242 static struct vport *gre_create(const struct vport_parms *parms) 243 { 244 struct net *net = ovs_dp_get_net(parms->dp); 245 struct ovs_net *ovs_net; 246 struct vport *vport; 247 int err; 248 249 err = gre_init(); 250 if (err) 251 return ERR_PTR(err); 252 253 ovs_net = net_generic(net, ovs_net_id); 254 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) { 255 vport = ERR_PTR(-EEXIST); 256 goto error; 257 } 258 259 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms); 260 if (IS_ERR(vport)) 261 goto error; 262 263 strncpy(vport_priv(vport), parms->name, IFNAMSIZ); 264 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport); 265 return vport; 266 267 error: 268 gre_exit(); 269 return vport; 270 } 271 272 static void gre_tnl_destroy(struct vport *vport) 273 { 274 struct net *net = ovs_dp_get_net(vport->dp); 275 struct ovs_net *ovs_net; 276 277 ovs_net = net_generic(net, ovs_net_id); 278 279 RCU_INIT_POINTER(ovs_net->vport_net.gre_vport, NULL); 280 ovs_vport_deferred_free(vport); 281 gre_exit(); 282 } 283 284 const struct vport_ops ovs_gre_vport_ops = { 285 .type = OVS_VPORT_TYPE_GRE, 286 .create = gre_create, 287 .destroy = gre_tnl_destroy, 288 .get_name = gre_get_name, 289 .send = gre_tnl_send, 290 }; 291