datapath/vport-gre.c

   1 /*
   2  * Copyright (c) 2007-2012 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 #include <linux/kconfig.h>
  20 #if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/if.h>
  24 #include <linux/skbuff.h>
  25 #include <linux/ip.h>
  26 #include <linux/if_tunnel.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/net_namespace.h>
  37 #include <net/netns/generic.h>
  38 #include <net/route.h>
  39 #include <net/xfrm.h>
  40
  41 #include <net/icmp.h>
  42 #include <net/ip.h>
  43 #include <net/ip_tunnels.h>
  44 #include <net/gre.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                                       __be32 seq, __be16 gre64_flag)
  68 {
  69         const struct ovs_key_ipv4_tunnel *tun_key = &OVS_CB(skb)->tun_info->tunnel;
  70         struct tnl_ptk_info tpi;
  71
  72         skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM));
  73         if (IS_ERR(skb))
  74                 return NULL;
  75
  76         tpi.flags = filter_tnl_flags(tun_key->tun_flags) | gre64_flag;
  77
  78         tpi.proto = htons(ETH_P_TEB);
  79         tpi.key = be64_get_low32(tun_key->tun_id);
  80         tpi.seq = seq;
  81         gre_build_header(skb, &tpi, tunnel_hlen);
  82
  83         return skb;
  84 }
  85
  86 static __be64 key_to_tunnel_id(__be32 key, __be32 seq)
  87 {
  88 #ifdef __BIG_ENDIAN
  89         return (__force __be64)((__force u64)seq << 32 | (__force u32)key);
  90 #else
  91         return (__force __be64)((__force u64)key << 32 | (__force u32)seq);
  92 #endif
  93 }
  94
  95 /* Called with rcu_read_lock and BH disabled. */
  96 static int gre_rcv(struct sk_buff *skb,
  97                    const struct tnl_ptk_info *tpi)
  98 {
  99         struct ovs_tunnel_info tun_info;
 100         struct ovs_net *ovs_net;
 101         struct vport *vport;
 102         __be64 key;
 103
 104         ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
 105         if ((tpi->flags & TUNNEL_KEY) && (tpi->flags & TUNNEL_SEQ))
 106                 vport = rcu_dereference(ovs_net->vport_net.gre64_vport);
 107         else
 108                 vport = rcu_dereference(ovs_net->vport_net.gre_vport);
 109         if (unlikely(!vport))
 110                 return PACKET_REJECT;
 111
 112         key = key_to_tunnel_id(tpi->key, tpi->seq);
 113         ovs_flow_tun_info_init(&tun_info, ip_hdr(skb), key,
 114                                filter_tnl_flags(tpi->flags));
 115
 116         ovs_vport_receive(vport, skb, &tun_info);
 117         return PACKET_RCVD;
 118 }
 119
 120 /* Called with rcu_read_lock and BH disabled. */
 121 static int gre_err(struct sk_buff *skb, u32 info,
 122                    const struct tnl_ptk_info *tpi)
 123 {
 124         struct ovs_net *ovs_net;
 125         struct vport *vport;
 126
 127         ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
 128         if ((tpi->flags & TUNNEL_KEY) && (tpi->flags & TUNNEL_SEQ))
 129                 vport = rcu_dereference(ovs_net->vport_net.gre64_vport);
 130         else
 131                 vport = rcu_dereference(ovs_net->vport_net.gre_vport);
 132
 133         if (unlikely(!vport))
 134                 return PACKET_REJECT;
 135         else
 136                 return PACKET_RCVD;
 137 }
 138
 139 static int __send(struct vport *vport, struct sk_buff *skb,
 140                   int tunnel_hlen,
 141                   __be32 seq, __be16 gre64_flag)
 142 {
 143         struct ovs_key_ipv4_tunnel *tun_key = &OVS_CB(skb)->tun_info->tunnel;
 144         struct rtable *rt;
 145         int min_headroom;
 146         __be16 df;
 147         __be32 saddr;
 148         int err;
 149
 150         /* Route lookup */
 151         saddr = tun_key->ipv4_src;
 152         rt = find_route(ovs_dp_get_net(vport->dp),
 153                         &saddr, tun_key->ipv4_dst,
 154                         IPPROTO_GRE, tun_key->ipv4_tos,
 155                         skb->mark);
 156         if (IS_ERR(rt)) {
 157                 err = PTR_ERR(rt);
 158                 goto error;
 159         }
 160
 161         min_headroom = LL_RESERVED_SPACE(rt_dst(rt).dev) + rt_dst(rt).header_len
 162                         + tunnel_hlen + sizeof(struct iphdr)
 163                         + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
 164
 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                 vlan_set_tci(skb, 0);
 183         }
 184
 185         /* Push Tunnel header. */
 186         skb = __build_header(skb, tunnel_hlen, seq, gre64_flag);
 187         if (unlikely(!skb)) {
 188                 err = 0;
 189                 goto err_free_rt;
 190         }
 191
 192         df = tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
 193         skb->local_df = 1;
 194
 195         return iptunnel_xmit(rt, skb, saddr,
 196                              tun_key->ipv4_dst, IPPROTO_GRE,
 197                              tun_key->ipv4_tos,
 198                              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_send(struct vport *vport, struct sk_buff *skb)
 284 {
 285         int hlen;
 286
 287         if (unlikely(!OVS_CB(skb)->tun_info))
 288                 return -EINVAL;
 289
 290         hlen = ip_gre_calc_hlen(OVS_CB(skb)->tun_info->tunnel.tun_flags);
 291
 292         return __send(vport, skb, hlen, 0, 0);
 293 }
 294
 295 const struct vport_ops ovs_gre_vport_ops = {
 296         .type           = OVS_VPORT_TYPE_GRE,
 297         .create         = gre_create,
 298         .destroy        = gre_tnl_destroy,
 299         .get_name       = gre_get_name,
 300         .send           = gre_send,
 301 };
 302
 303 /* GRE64 vport. */
 304 static struct vport *gre64_create(const struct vport_parms *parms)
 305 {
 306         struct net *net = ovs_dp_get_net(parms->dp);
 307         struct ovs_net *ovs_net;
 308         struct vport *vport;
 309         int err;
 310
 311         err = gre_init();
 312         if (err)
 313                 return ERR_PTR(err);
 314
 315         ovs_net = net_generic(net, ovs_net_id);
 316         if (ovsl_dereference(ovs_net->vport_net.gre64_vport)) {
 317                 vport = ERR_PTR(-EEXIST);
 318                 goto error;
 319         }
 320
 321         vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre64_vport_ops, parms);
 322         if (IS_ERR(vport))
 323                 goto error;
 324
 325         strncpy(vport_priv(vport), parms->name, IFNAMSIZ);
 326         rcu_assign_pointer(ovs_net->vport_net.gre64_vport, vport);
 327         return vport;
 328 error:
 329         gre_exit();
 330         return vport;
 331 }
 332
 333 static void gre64_tnl_destroy(struct vport *vport)
 334 {
 335         struct net *net = ovs_dp_get_net(vport->dp);
 336         struct ovs_net *ovs_net;
 337
 338         ovs_net = net_generic(net, ovs_net_id);
 339
 340         rcu_assign_pointer(ovs_net->vport_net.gre64_vport, NULL);
 341         ovs_vport_deferred_free(vport);
 342         gre_exit();
 343 }
 344
 345 static __be32 be64_get_high32(__be64 x)
 346 {
 347 #ifdef __BIG_ENDIAN
 348         return (__force __be32)((__force u64)x >> 32);
 349 #else
 350         return (__force __be32)x;
 351 #endif
 352 }
 353
 354 static int gre64_send(struct vport *vport, struct sk_buff *skb)
 355 {
 356         int hlen = GRE_HEADER_SECTION +         /* GRE Hdr */
 357                    GRE_HEADER_SECTION +         /* GRE Key */
 358                    GRE_HEADER_SECTION;          /* GRE SEQ */
 359         __be32 seq;
 360
 361         if (unlikely(!OVS_CB(skb)->tun_info))
 362                 return -EINVAL;
 363
 364         if (OVS_CB(skb)->tun_info->tunnel.tun_flags & TUNNEL_CSUM)
 365                 hlen += GRE_HEADER_SECTION;
 366
 367         seq = be64_get_high32(OVS_CB(skb)->tun_info->tunnel.tun_id);
 368         return __send(vport, skb, hlen, seq, (TUNNEL_KEY|TUNNEL_SEQ));
 369 }
 370
 371 const struct vport_ops ovs_gre64_vport_ops = {
 372         .type           = OVS_VPORT_TYPE_GRE64,
 373         .create         = gre64_create,
 374         .destroy        = gre64_tnl_destroy,
 375         .get_name       = gre_get_name,
 376         .send           = gre64_send,
 377 };
 378 #endif