net/openvswitch/actions.c

   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/skbuff.h>
  22 #include <linux/in.h>
  23 #include <linux/ip.h>
  24 #include <linux/openvswitch.h>
  25 #include <linux/sctp.h>
  26 #include <linux/tcp.h>
  27 #include <linux/udp.h>
  28 #include <linux/in6.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/ip.h>
  32 #include <net/ipv6.h>
  33 #include <net/checksum.h>
  34 #include <net/dsfield.h>
  35 #include <net/sctp/checksum.h>
  36
  37 #include "datapath.h"
  38 #include "flow.h"
  39 #include "vport.h"
  40
  41 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
  42                               struct sw_flow_key *key,
  43                               const struct nlattr *attr, int len);
  44
  45 struct deferred_action {
  46         struct sk_buff *skb;
  47         const struct nlattr *actions;
  48
  49         /* Store pkt_key clone when creating deferred action. */
  50         struct sw_flow_key pkt_key;
  51 };
  52
  53 #define DEFERRED_ACTION_FIFO_SIZE 10
  54 struct action_fifo {
  55         int head;
  56         int tail;
  57         /* Deferred action fifo queue storage. */
  58         struct deferred_action fifo[DEFERRED_ACTION_FIFO_SIZE];
  59 };
  60
  61 static struct action_fifo __percpu *action_fifos;
  62 static DEFINE_PER_CPU(int, exec_actions_level);
  63
  64 static void action_fifo_init(struct action_fifo *fifo)
  65 {
  66         fifo->head = 0;
  67         fifo->tail = 0;
  68 }
  69
  70 static bool action_fifo_is_empty(struct action_fifo *fifo)
  71 {
  72         return (fifo->head == fifo->tail);
  73 }
  74
  75 static struct deferred_action *action_fifo_get(struct action_fifo *fifo)
  76 {
  77         if (action_fifo_is_empty(fifo))
  78                 return NULL;
  79
  80         return &fifo->fifo[fifo->tail++];
  81 }
  82
  83 static struct deferred_action *action_fifo_put(struct action_fifo *fifo)
  84 {
  85         if (fifo->head >= DEFERRED_ACTION_FIFO_SIZE - 1)
  86                 return NULL;
  87
  88         return &fifo->fifo[fifo->head++];
  89 }
  90
  91 /* Return true if fifo is not full */
  92 static struct deferred_action *add_deferred_actions(struct sk_buff *skb,
  93                                                     struct sw_flow_key *key,
  94                                                     const struct nlattr *attr)
  95 {
  96         struct action_fifo *fifo;
  97         struct deferred_action *da;
  98
  99         fifo = this_cpu_ptr(action_fifos);
 100         da = action_fifo_put(fifo);
 101         if (da) {
 102                 da->skb = skb;
 103                 da->actions = attr;
 104                 da->pkt_key = *key;
 105         }
 106
 107         return da;
 108 }
 109
 110 static int make_writable(struct sk_buff *skb, int write_len)
 111 {
 112         if (!pskb_may_pull(skb, write_len))
 113                 return -ENOMEM;
 114
 115         if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
 116                 return 0;
 117
 118         return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
 119 }
 120
 121 /* remove VLAN header from packet and update csum accordingly. */
 122 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 123 {
 124         struct vlan_hdr *vhdr;
 125         int err;
 126
 127         err = make_writable(skb, VLAN_ETH_HLEN);
 128         if (unlikely(err))
 129                 return err;
 130
 131         if (skb->ip_summed == CHECKSUM_COMPLETE)
 132                 skb->csum = csum_sub(skb->csum, csum_partial(skb->data
 133                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
 134
 135         vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
 136         *current_tci = vhdr->h_vlan_TCI;
 137
 138         memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
 139         __skb_pull(skb, VLAN_HLEN);
 140
 141         vlan_set_encap_proto(skb, vhdr);
 142         skb->mac_header += VLAN_HLEN;
 143         if (skb_network_offset(skb) < ETH_HLEN)
 144                 skb_set_network_header(skb, ETH_HLEN);
 145         skb_reset_mac_len(skb);
 146
 147         return 0;
 148 }
 149
 150 static int pop_vlan(struct sk_buff *skb)
 151 {
 152         __be16 tci;
 153         int err;
 154
 155         if (likely(vlan_tx_tag_present(skb))) {
 156                 skb->vlan_tci = 0;
 157         } else {
 158                 if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
 159                              skb->len < VLAN_ETH_HLEN))
 160                         return 0;
 161
 162                 err = __pop_vlan_tci(skb, &tci);
 163                 if (err)
 164                         return err;
 165         }
 166         /* move next vlan tag to hw accel tag */
 167         if (likely(skb->protocol != htons(ETH_P_8021Q) ||
 168                    skb->len < VLAN_ETH_HLEN))
 169                 return 0;
 170
 171         err = __pop_vlan_tci(skb, &tci);
 172         if (unlikely(err))
 173                 return err;
 174
 175         __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), ntohs(tci));
 176         return 0;
 177 }
 178
 179 static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan)
 180 {
 181         if (unlikely(vlan_tx_tag_present(skb))) {
 182                 u16 current_tag;
 183
 184                 /* push down current VLAN tag */
 185                 current_tag = vlan_tx_tag_get(skb);
 186
 187                 if (!__vlan_put_tag(skb, skb->vlan_proto, current_tag))
 188                         return -ENOMEM;
 189
 190                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 191                         skb->csum = csum_add(skb->csum, csum_partial(skb->data
 192                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
 193
 194         }
 195         __vlan_hwaccel_put_tag(skb, vlan->vlan_tpid, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
 196         return 0;
 197 }
 198
 199 static int set_eth_addr(struct sk_buff *skb,
 200                         const struct ovs_key_ethernet *eth_key)
 201 {
 202         int err;
 203         err = make_writable(skb, ETH_HLEN);
 204         if (unlikely(err))
 205                 return err;
 206
 207         skb_postpull_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 208
 209         ether_addr_copy(eth_hdr(skb)->h_source, eth_key->eth_src);
 210         ether_addr_copy(eth_hdr(skb)->h_dest, eth_key->eth_dst);
 211
 212         ovs_skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 213
 214         return 0;
 215 }
 216
 217 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
 218                                 __be32 *addr, __be32 new_addr)
 219 {
 220         int transport_len = skb->len - skb_transport_offset(skb);
 221
 222         if (nh->protocol == IPPROTO_TCP) {
 223                 if (likely(transport_len >= sizeof(struct tcphdr)))
 224                         inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
 225                                                  *addr, new_addr, 1);
 226         } else if (nh->protocol == IPPROTO_UDP) {
 227                 if (likely(transport_len >= sizeof(struct udphdr))) {
 228                         struct udphdr *uh = udp_hdr(skb);
 229
 230                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 231                                 inet_proto_csum_replace4(&uh->check, skb,
 232                                                          *addr, new_addr, 1);
 233                                 if (!uh->check)
 234                                         uh->check = CSUM_MANGLED_0;
 235                         }
 236                 }
 237         }
 238
 239         csum_replace4(&nh->check, *addr, new_addr);
 240         skb_clear_hash(skb);
 241         *addr = new_addr;
 242 }
 243
 244 static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
 245                                  __be32 addr[4], const __be32 new_addr[4])
 246 {
 247         int transport_len = skb->len - skb_transport_offset(skb);
 248
 249         if (l4_proto == NEXTHDR_TCP) {
 250                 if (likely(transport_len >= sizeof(struct tcphdr)))
 251                         inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
 252                                                   addr, new_addr, 1);
 253         } else if (l4_proto == NEXTHDR_UDP) {
 254                 if (likely(transport_len >= sizeof(struct udphdr))) {
 255                         struct udphdr *uh = udp_hdr(skb);
 256
 257                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 258                                 inet_proto_csum_replace16(&uh->check, skb,
 259                                                           addr, new_addr, 1);
 260                                 if (!uh->check)
 261                                         uh->check = CSUM_MANGLED_0;
 262                         }
 263                 }
 264         } else if (l4_proto == NEXTHDR_ICMP) {
 265                 if (likely(transport_len >= sizeof(struct icmp6hdr)))
 266                         inet_proto_csum_replace16(&icmp6_hdr(skb)->icmp6_cksum,
 267                                                   skb, addr, new_addr, 1);
 268         }
 269 }
 270
 271 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 272                           __be32 addr[4], const __be32 new_addr[4],
 273                           bool recalculate_csum)
 274 {
 275         if (recalculate_csum)
 276                 update_ipv6_checksum(skb, l4_proto, addr, new_addr);
 277
 278         skb_clear_hash(skb);
 279         memcpy(addr, new_addr, sizeof(__be32[4]));
 280 }
 281
 282 static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
 283 {
 284         nh->priority = tc >> 4;
 285         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
 286 }
 287
 288 static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
 289 {
 290         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
 291         nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
 292         nh->flow_lbl[2] = fl & 0x000000FF;
 293 }
 294
 295 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
 296 {
 297         csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
 298         nh->ttl = new_ttl;
 299 }
 300
 301 static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
 302 {
 303         struct iphdr *nh;
 304         int err;
 305
 306         err = make_writable(skb, skb_network_offset(skb) +
 307                                  sizeof(struct iphdr));
 308         if (unlikely(err))
 309                 return err;
 310
 311         nh = ip_hdr(skb);
 312
 313         if (ipv4_key->ipv4_src != nh->saddr)
 314                 set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
 315
 316         if (ipv4_key->ipv4_dst != nh->daddr)
 317                 set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
 318
 319         if (ipv4_key->ipv4_tos != nh->tos)
 320                 ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
 321
 322         if (ipv4_key->ipv4_ttl != nh->ttl)
 323                 set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
 324
 325         return 0;
 326 }
 327
 328 static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
 329 {
 330         struct ipv6hdr *nh;
 331         int err;
 332         __be32 *saddr;
 333         __be32 *daddr;
 334
 335         err = make_writable(skb, skb_network_offset(skb) +
 336                             sizeof(struct ipv6hdr));
 337         if (unlikely(err))
 338                 return err;
 339
 340         nh = ipv6_hdr(skb);
 341         saddr = (__be32 *)&nh->saddr;
 342         daddr = (__be32 *)&nh->daddr;
 343
 344         if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
 345                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
 346                               ipv6_key->ipv6_src, true);
 347
 348         if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
 349                 unsigned int offset = 0;
 350                 int flags = IP6_FH_F_SKIP_RH;
 351                 bool recalc_csum = true;
 352
 353                 if (ipv6_ext_hdr(nh->nexthdr))
 354                         recalc_csum = ipv6_find_hdr(skb, &offset,
 355                                                     NEXTHDR_ROUTING, NULL,
 356                                                     &flags) != NEXTHDR_ROUTING;
 357
 358                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
 359                               ipv6_key->ipv6_dst, recalc_csum);
 360         }
 361
 362         set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
 363         set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
 364         nh->hop_limit = ipv6_key->ipv6_hlimit;
 365
 366         return 0;
 367 }
 368
 369 /* Must follow make_writable() since that can move the skb data. */
 370 static void set_tp_port(struct sk_buff *skb, __be16 *port,
 371                          __be16 new_port, __sum16 *check)
 372 {
 373         inet_proto_csum_replace2(check, skb, *port, new_port, 0);
 374         *port = new_port;
 375         skb_clear_hash(skb);
 376 }
 377
 378 static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
 379 {
 380         struct udphdr *uh = udp_hdr(skb);
 381
 382         if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
 383                 set_tp_port(skb, port, new_port, &uh->check);
 384
 385                 if (!uh->check)
 386                         uh->check = CSUM_MANGLED_0;
 387         } else {
 388                 *port = new_port;
 389                 skb_clear_hash(skb);
 390         }
 391 }
 392
 393 static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
 394 {
 395         struct udphdr *uh;
 396         int err;
 397
 398         err = make_writable(skb, skb_transport_offset(skb) +
 399                                  sizeof(struct udphdr));
 400         if (unlikely(err))
 401                 return err;
 402
 403         uh = udp_hdr(skb);
 404         if (udp_port_key->udp_src != uh->source)
 405                 set_udp_port(skb, &uh->source, udp_port_key->udp_src);
 406
 407         if (udp_port_key->udp_dst != uh->dest)
 408                 set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
 409
 410         return 0;
 411 }
 412
 413 static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 414 {
 415         struct tcphdr *th;
 416         int err;
 417
 418         err = make_writable(skb, skb_transport_offset(skb) +
 419                                  sizeof(struct tcphdr));
 420         if (unlikely(err))
 421                 return err;
 422
 423         th = tcp_hdr(skb);
 424         if (tcp_port_key->tcp_src != th->source)
 425                 set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
 426
 427         if (tcp_port_key->tcp_dst != th->dest)
 428                 set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
 429
 430         return 0;
 431 }
 432
 433 static int set_sctp(struct sk_buff *skb,
 434                      const struct ovs_key_sctp *sctp_port_key)
 435 {
 436         struct sctphdr *sh;
 437         int err;
 438         unsigned int sctphoff = skb_transport_offset(skb);
 439
 440         err = make_writable(skb, sctphoff + sizeof(struct sctphdr));
 441         if (unlikely(err))
 442                 return err;
 443
 444         sh = sctp_hdr(skb);
 445         if (sctp_port_key->sctp_src != sh->source ||
 446             sctp_port_key->sctp_dst != sh->dest) {
 447                 __le32 old_correct_csum, new_csum, old_csum;
 448
 449                 old_csum = sh->checksum;
 450                 old_correct_csum = sctp_compute_cksum(skb, sctphoff);
 451
 452                 sh->source = sctp_port_key->sctp_src;
 453                 sh->dest = sctp_port_key->sctp_dst;
 454
 455                 new_csum = sctp_compute_cksum(skb, sctphoff);
 456
 457                 /* Carry any checksum errors through. */
 458                 sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
 459
 460                 skb_clear_hash(skb);
 461         }
 462
 463         return 0;
 464 }
 465
 466 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 467 {
 468         struct vport *vport;
 469
 470         if (unlikely(!skb))
 471                 return -ENOMEM;
 472
 473         vport = ovs_vport_rcu(dp, out_port);
 474         if (unlikely(!vport)) {
 475                 kfree_skb(skb);
 476                 return -ENODEV;
 477         }
 478
 479         ovs_vport_send(vport, skb);
 480         return 0;
 481 }
 482
 483 static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 484                             struct sw_flow_key *key, const struct nlattr *attr)
 485 {
 486         struct dp_upcall_info upcall;
 487         const struct nlattr *a;
 488         int rem;
 489
 490         upcall.cmd = OVS_PACKET_CMD_ACTION;
 491         upcall.key = key;
 492         upcall.userdata = NULL;
 493         upcall.portid = 0;
 494
 495         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 496                  a = nla_next(a, &rem)) {
 497                 switch (nla_type(a)) {
 498                 case OVS_USERSPACE_ATTR_USERDATA:
 499                         upcall.userdata = a;
 500                         break;
 501
 502                 case OVS_USERSPACE_ATTR_PID:
 503                         upcall.portid = nla_get_u32(a);
 504                         break;
 505                 }
 506         }
 507
 508         return ovs_dp_upcall(dp, skb, &upcall);
 509 }
 510
 511 static bool last_action(const struct nlattr *a, int rem)
 512 {
 513         return a->nla_len == rem;
 514 }
 515
 516 static int sample(struct datapath *dp, struct sk_buff *skb,
 517                   struct sw_flow_key *key, const struct nlattr *attr)
 518 {
 519         const struct nlattr *acts_list = NULL;
 520         const struct nlattr *a;
 521         int rem;
 522
 523         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 524                  a = nla_next(a, &rem)) {
 525                 switch (nla_type(a)) {
 526                 case OVS_SAMPLE_ATTR_PROBABILITY:
 527                         if (prandom_u32() >= nla_get_u32(a))
 528                                 return 0;
 529                         break;
 530
 531                 case OVS_SAMPLE_ATTR_ACTIONS:
 532                         acts_list = a;
 533                         break;
 534                 }
 535         }
 536
 537         rem = nla_len(acts_list);
 538         a = nla_data(acts_list);
 539
 540         /* Actions list is empty, do nothing */
 541         if (unlikely(!rem))
 542                 return 0;
 543
 544         /* The only known usage of sample action is having a single user-space
 545          * action. Treat this usage as a special case.
 546          * The output_userspace() should clone the skb to be sent to the
 547          * user space. This skb will be consumed by its caller.
 548          */
 549         if (likely(nla_type(a) == OVS_ACTION_ATTR_USERSPACE &&
 550                    last_action(a, rem)))
 551                 return output_userspace(dp, skb, key, a);
 552
 553         skb = skb_clone(skb, GFP_ATOMIC);
 554         if (!skb)
 555                 /* Skip the sample action when out of memory. */
 556                 return 0;
 557
 558         if (!add_deferred_actions(skb, key, a)) {
 559                 if (net_ratelimit())
 560                         pr_warn("%s: deferred actions limit reached, dropping sample action\n",
 561                                 ovs_dp_name(dp));
 562
 563                 kfree_skb(skb);
 564         }
 565         return 0;
 566 }
 567
 568 static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
 569                          const struct nlattr *attr)
 570 {
 571         struct ovs_action_hash *hash_act = nla_data(attr);
 572         u32 hash = 0;
 573
 574         /* OVS_HASH_ALG_L4 is the only possible hash algorithm.  */
 575         hash = skb_get_hash(skb);
 576         hash = jhash_1word(hash, hash_act->hash_basis);
 577         if (!hash)
 578                 hash = 0x1;
 579
 580         key->ovs_flow_hash = hash;
 581 }
 582
 583 static int execute_set_action(struct sk_buff *skb,
 584                                  const struct nlattr *nested_attr)
 585 {
 586         int err = 0;
 587
 588         switch (nla_type(nested_attr)) {
 589         case OVS_KEY_ATTR_PRIORITY:
 590                 skb->priority = nla_get_u32(nested_attr);
 591                 break;
 592
 593         case OVS_KEY_ATTR_SKB_MARK:
 594                 skb->mark = nla_get_u32(nested_attr);
 595                 break;
 596
 597         case OVS_KEY_ATTR_TUNNEL_INFO:
 598                 OVS_CB(skb)->egress_tun_info = nla_data(nested_attr);
 599                 break;
 600
 601         case OVS_KEY_ATTR_ETHERNET:
 602                 err = set_eth_addr(skb, nla_data(nested_attr));
 603                 break;
 604
 605         case OVS_KEY_ATTR_IPV4:
 606                 err = set_ipv4(skb, nla_data(nested_attr));
 607                 break;
 608
 609         case OVS_KEY_ATTR_IPV6:
 610                 err = set_ipv6(skb, nla_data(nested_attr));
 611                 break;
 612
 613         case OVS_KEY_ATTR_TCP:
 614                 err = set_tcp(skb, nla_data(nested_attr));
 615                 break;
 616
 617         case OVS_KEY_ATTR_UDP:
 618                 err = set_udp(skb, nla_data(nested_attr));
 619                 break;
 620
 621         case OVS_KEY_ATTR_SCTP:
 622                 err = set_sctp(skb, nla_data(nested_attr));
 623                 break;
 624         }
 625
 626         return err;
 627 }
 628
 629 static int execute_recirc(struct datapath *dp, struct sk_buff *skb,
 630                           struct sw_flow_key *key,
 631                           const struct nlattr *a, int rem)
 632 {
 633         struct deferred_action *da;
 634         int err;
 635
 636         err = ovs_flow_key_update(skb, key);
 637         if (err)
 638                 return err;
 639
 640         if (!last_action(a, rem)) {
 641                 /* Recirc action is the not the last action
 642                  * of the action list, need to clone the skb.
 643                  */
 644                 skb = skb_clone(skb, GFP_ATOMIC);
 645
 646                 /* Skip the recirc action when out of memory, but
 647                  * continue on with the rest of the action list.
 648                  */
 649                 if (!skb)
 650                         return 0;
 651         }
 652
 653         da = add_deferred_actions(skb, key, NULL);
 654         if (da) {
 655                 da->pkt_key.recirc_id = nla_get_u32(a);
 656         } else {
 657                 kfree_skb(skb);
 658
 659                 if (net_ratelimit())
 660                         pr_warn("%s: deferred action limit reached, drop recirc action\n",
 661                                 ovs_dp_name(dp));
 662         }
 663
 664         return 0;
 665 }
 666
 667 /* Execute a list of actions against 'skb'. */
 668 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 669                               struct sw_flow_key *key,
 670                               const struct nlattr *attr, int len)
 671 {
 672         /* Every output action needs a separate clone of 'skb', but the common
 673          * case is just a single output action, so that doing a clone and
 674          * then freeing the original skbuff is wasteful.  So the following code
 675          * is slightly obscure just to avoid that. */
 676         int prev_port = -1;
 677         const struct nlattr *a;
 678         int rem;
 679
 680         for (a = attr, rem = len; rem > 0;
 681              a = nla_next(a, &rem)) {
 682                 int err = 0;
 683
 684                 if (prev_port != -1) {
 685                         do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
 686                         prev_port = -1;
 687                 }
 688
 689                 switch (nla_type(a)) {
 690                 case OVS_ACTION_ATTR_OUTPUT:
 691                         prev_port = nla_get_u32(a);
 692                         break;
 693
 694                 case OVS_ACTION_ATTR_USERSPACE:
 695                         output_userspace(dp, skb, key, a);
 696                         break;
 697
 698                 case OVS_ACTION_ATTR_HASH:
 699                         execute_hash(skb, key, a);
 700                         break;
 701
 702                 case OVS_ACTION_ATTR_PUSH_VLAN:
 703                         err = push_vlan(skb, nla_data(a));
 704                         if (unlikely(err)) /* skb already freed. */
 705                                 return err;
 706                         break;
 707
 708                 case OVS_ACTION_ATTR_POP_VLAN:
 709                         err = pop_vlan(skb);
 710                         break;
 711
 712                 case OVS_ACTION_ATTR_RECIRC:
 713                         err = execute_recirc(dp, skb, key, a, rem);
 714                         if (last_action(a, rem)) {
 715                                 /* If this is the last action, the skb has
 716                                  * been consumed or freed.
 717                                  * Return immediately.
 718                                  */
 719                                 return err;
 720                         }
 721                         break;
 722
 723                 case OVS_ACTION_ATTR_SET:
 724                         err = execute_set_action(skb, nla_data(a));
 725                         break;
 726
 727                 case OVS_ACTION_ATTR_SAMPLE:
 728                         err = sample(dp, skb, key, a);
 729                         break;
 730                 }
 731
 732                 if (unlikely(err)) {
 733                         kfree_skb(skb);
 734                         return err;
 735                 }
 736         }
 737
 738         if (prev_port != -1)
 739                 do_output(dp, skb, prev_port);
 740         else
 741                 consume_skb(skb);
 742
 743         return 0;
 744 }
 745
 746 static void process_deferred_actions(struct datapath *dp)
 747 {
 748         struct action_fifo *fifo = this_cpu_ptr(action_fifos);
 749
 750         /* Do not touch the FIFO in case there is no deferred actions. */
 751         if (action_fifo_is_empty(fifo))
 752                 return;
 753
 754         /* Finishing executing all deferred actions. */
 755         do {
 756                 struct deferred_action *da = action_fifo_get(fifo);
 757                 struct sk_buff *skb = da->skb;
 758                 struct sw_flow_key *key = &da->pkt_key;
 759                 const struct nlattr *actions = da->actions;
 760
 761                 if (actions)
 762                         do_execute_actions(dp, skb, key, actions,
 763                                            nla_len(actions));
 764                 else
 765                         ovs_dp_process_packet(skb, key);
 766         } while (!action_fifo_is_empty(fifo));
 767
 768         /* Reset FIFO for the next packet.  */
 769         action_fifo_init(fifo);
 770 }
 771
 772 /* Execute a list of actions against 'skb'. */
 773 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
 774                         struct sw_flow_key *key)
 775 {
 776         int level = this_cpu_read(exec_actions_level);
 777         struct sw_flow_actions *acts;
 778         int err;
 779
 780         acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
 781
 782         this_cpu_inc(exec_actions_level);
 783         OVS_CB(skb)->egress_tun_info = NULL;
 784         err = do_execute_actions(dp, skb, key,
 785                                  acts->actions, acts->actions_len);
 786
 787         if (!level)
 788                 process_deferred_actions(dp);
 789
 790         this_cpu_dec(exec_actions_level);
 791         return err;
 792 }
 793
 794 int action_fifos_init(void)
 795 {
 796         action_fifos = alloc_percpu(struct action_fifo);
 797         if (!action_fifos)
 798                 return -ENOMEM;
 799
 800         return 0;
 801 }
 802
 803 void action_fifos_exit(void)
 804 {
 805         free_percpu(action_fifos);
 806 }