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/if_vlan.h> 28 #include <linux/in.h> 29 #include <linux/in_route.h> 30 #include <linux/inetdevice.h> 31 #include <linux/jhash.h> 32 #include <linux/list.h> 33 #include <linux/kernel.h> 34 #include <linux/workqueue.h> 35 #include <linux/rculist.h> 36 #include <net/route.h> 37 #include <net/xfrm.h> 38 39 #include <net/icmp.h> 40 #include <net/ip.h> 41 #include <net/ip_tunnels.h> 42 #include <net/gre.h> 43 #include <net/net_namespace.h> 44 #include <net/netns/generic.h> 45 #include <net/protocol.h> 46 47 #include "datapath.h" 48 #include "vport.h" 49 50 /* Returns the least-significant 32 bits of a __be64. */ 51 static __be32 be64_get_low32(__be64 x) 52 { 53 #ifdef __BIG_ENDIAN 54 return (__force __be32)x; 55 #else 56 return (__force __be32)((__force u64)x >> 32); 57 #endif 58 } 59 60 static __be16 filter_tnl_flags(__be16 flags) 61 { 62 return flags & (TUNNEL_CSUM | TUNNEL_KEY); 63 } 64 65 static struct sk_buff *__build_header(struct sk_buff *skb, 66 int tunnel_hlen) 67 { 68 const struct ovs_key_ipv4_tunnel *tun_key = OVS_CB(skb)->tun_key; 69 struct tnl_ptk_info tpi; 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_key_ipv4_tunnel tun_key; 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_key_init(&tun_key, ip_hdr(skb), key, 109 filter_tnl_flags(tpi->flags)); 110 111 ovs_vport_receive(vport, skb, &tun_key); 112 return PACKET_RCVD; 113 } 114 115 static int gre_tnl_send(struct vport *vport, struct sk_buff *skb) 116 { 117 struct net *net = ovs_dp_get_net(vport->dp); 118 struct flowi4 fl; 119 struct rtable *rt; 120 int min_headroom; 121 int tunnel_hlen; 122 __be16 df; 123 int err; 124 125 if (unlikely(!OVS_CB(skb)->tun_key)) { 126 err = -EINVAL; 127 goto error; 128 } 129 130 /* Route lookup */ 131 memset(&fl, 0, sizeof(fl)); 132 fl.daddr = OVS_CB(skb)->tun_key->ipv4_dst; 133 fl.saddr = OVS_CB(skb)->tun_key->ipv4_src; 134 fl.flowi4_tos = RT_TOS(OVS_CB(skb)->tun_key->ipv4_tos); 135 fl.flowi4_mark = skb->mark; 136 fl.flowi4_proto = IPPROTO_GRE; 137 138 rt = ip_route_output_key(net, &fl); 139 if (IS_ERR(rt)) 140 return PTR_ERR(rt); 141 142 tunnel_hlen = ip_gre_calc_hlen(OVS_CB(skb)->tun_key->tun_flags); 143 144 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len 145 + tunnel_hlen + sizeof(struct iphdr) 146 + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0); 147 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) { 148 int head_delta = SKB_DATA_ALIGN(min_headroom - 149 skb_headroom(skb) + 150 16); 151 err = pskb_expand_head(skb, max_t(int, head_delta, 0), 152 0, GFP_ATOMIC); 153 if (unlikely(err)) 154 goto err_free_rt; 155 } 156 157 if (vlan_tx_tag_present(skb)) { 158 if (unlikely(!__vlan_put_tag(skb, 159 skb->vlan_proto, 160 vlan_tx_tag_get(skb)))) { 161 err = -ENOMEM; 162 goto err_free_rt; 163 } 164 skb->vlan_tci = 0; 165 } 166 167 /* Push Tunnel header. */ 168 skb = __build_header(skb, tunnel_hlen); 169 if (unlikely(!skb)) { 170 err = 0; 171 goto err_free_rt; 172 } 173 174 df = OVS_CB(skb)->tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? 175 htons(IP_DF) : 0; 176 177 skb->local_df = 1; 178 179 return iptunnel_xmit(rt, skb, fl.saddr, 180 OVS_CB(skb)->tun_key->ipv4_dst, IPPROTO_GRE, 181 OVS_CB(skb)->tun_key->ipv4_tos, 182 OVS_CB(skb)->tun_key->ipv4_ttl, df, false); 183 err_free_rt: 184 ip_rt_put(rt); 185 error: 186 return err; 187 } 188 189 static struct gre_cisco_protocol gre_protocol = { 190 .handler = gre_rcv, 191 .priority = 1, 192 }; 193 194 static int gre_ports; 195 static int gre_init(void) 196 { 197 int err; 198 199 gre_ports++; 200 if (gre_ports > 1) 201 return 0; 202 203 err = gre_cisco_register(&gre_protocol); 204 if (err) 205 pr_warn("cannot register gre protocol handler\n"); 206 207 return err; 208 } 209 210 static void gre_exit(void) 211 { 212 gre_ports--; 213 if (gre_ports > 0) 214 return; 215 216 gre_cisco_unregister(&gre_protocol); 217 } 218 219 static const char *gre_get_name(const struct vport *vport) 220 { 221 return vport_priv(vport); 222 } 223 224 static struct vport *gre_create(const struct vport_parms *parms) 225 { 226 struct net *net = ovs_dp_get_net(parms->dp); 227 struct ovs_net *ovs_net; 228 struct vport *vport; 229 int err; 230 231 err = gre_init(); 232 if (err) 233 return ERR_PTR(err); 234 235 ovs_net = net_generic(net, ovs_net_id); 236 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) { 237 vport = ERR_PTR(-EEXIST); 238 goto error; 239 } 240 241 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms); 242 if (IS_ERR(vport)) 243 goto error; 244 245 strncpy(vport_priv(vport), parms->name, IFNAMSIZ); 246 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport); 247 return vport; 248 249 error: 250 gre_exit(); 251 return vport; 252 } 253 254 static void gre_tnl_destroy(struct vport *vport) 255 { 256 struct net *net = ovs_dp_get_net(vport->dp); 257 struct ovs_net *ovs_net; 258 259 ovs_net = net_generic(net, ovs_net_id); 260 261 rcu_assign_pointer(ovs_net->vport_net.gre_vport, NULL); 262 ovs_vport_deferred_free(vport); 263 gre_exit(); 264 } 265 266 const struct vport_ops ovs_gre_vport_ops = { 267 .type = OVS_VPORT_TYPE_GRE, 268 .create = gre_create, 269 .destroy = gre_tnl_destroy, 270 .get_name = gre_get_name, 271 .send = gre_tnl_send, 272 }; 273