net/openvswitch/actions.c

   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/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 "vport.h"
  39
  40 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
  41                         const struct nlattr *attr, int len, bool keep_skb);
  42
  43 static int make_writable(struct sk_buff *skb, int write_len)
  44 {
  45         if (!pskb_may_pull(skb, write_len))
  46                 return -ENOMEM;
  47
  48         if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
  49                 return 0;
  50
  51         return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
  52 }
  53
  54 /* remove VLAN header from packet and update csum accordingly. */
  55 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
  56 {
  57         struct vlan_hdr *vhdr;
  58         int err;
  59
  60         err = make_writable(skb, VLAN_ETH_HLEN);
  61         if (unlikely(err))
  62                 return err;
  63
  64         if (skb->ip_summed == CHECKSUM_COMPLETE)
  65                 skb->csum = csum_sub(skb->csum, csum_partial(skb->data
  66                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
  67
  68         vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
  69         *current_tci = vhdr->h_vlan_TCI;
  70
  71         memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
  72         __skb_pull(skb, VLAN_HLEN);
  73
  74         vlan_set_encap_proto(skb, vhdr);
  75         skb->mac_header += VLAN_HLEN;
  76         if (skb_network_offset(skb) < ETH_HLEN)
  77                 skb_set_network_header(skb, ETH_HLEN);
  78         skb_reset_mac_len(skb);
  79
  80         return 0;
  81 }
  82
  83 static int pop_vlan(struct sk_buff *skb)
  84 {
  85         __be16 tci;
  86         int err;
  87
  88         if (likely(vlan_tx_tag_present(skb))) {
  89                 skb->vlan_tci = 0;
  90         } else {
  91                 if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
  92                              skb->len < VLAN_ETH_HLEN))
  93                         return 0;
  94
  95                 err = __pop_vlan_tci(skb, &tci);
  96                 if (err)
  97                         return err;
  98         }
  99         /* move next vlan tag to hw accel tag */
 100         if (likely(skb->protocol != htons(ETH_P_8021Q) ||
 101                    skb->len < VLAN_ETH_HLEN))
 102                 return 0;
 103
 104         err = __pop_vlan_tci(skb, &tci);
 105         if (unlikely(err))
 106                 return err;
 107
 108         __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), ntohs(tci));
 109         return 0;
 110 }
 111
 112 static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan)
 113 {
 114         if (unlikely(vlan_tx_tag_present(skb))) {
 115                 u16 current_tag;
 116
 117                 /* push down current VLAN tag */
 118                 current_tag = vlan_tx_tag_get(skb);
 119
 120                 if (!__vlan_put_tag(skb, skb->vlan_proto, current_tag))
 121                         return -ENOMEM;
 122
 123                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 124                         skb->csum = csum_add(skb->csum, csum_partial(skb->data
 125                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
 126
 127         }
 128         __vlan_hwaccel_put_tag(skb, vlan->vlan_tpid, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
 129         return 0;
 130 }
 131
 132 static int set_eth_addr(struct sk_buff *skb,
 133                         const struct ovs_key_ethernet *eth_key)
 134 {
 135         int err;
 136         err = make_writable(skb, ETH_HLEN);
 137         if (unlikely(err))
 138                 return err;
 139
 140         skb_postpull_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 141
 142         memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
 143         memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);
 144
 145         ovs_skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 146
 147         return 0;
 148 }
 149
 150 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
 151                                 __be32 *addr, __be32 new_addr)
 152 {
 153         int transport_len = skb->len - skb_transport_offset(skb);
 154
 155         if (nh->protocol == IPPROTO_TCP) {
 156                 if (likely(transport_len >= sizeof(struct tcphdr)))
 157                         inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
 158                                                  *addr, new_addr, 1);
 159         } else if (nh->protocol == IPPROTO_UDP) {
 160                 if (likely(transport_len >= sizeof(struct udphdr))) {
 161                         struct udphdr *uh = udp_hdr(skb);
 162
 163                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 164                                 inet_proto_csum_replace4(&uh->check, skb,
 165                                                          *addr, new_addr, 1);
 166                                 if (!uh->check)
 167                                         uh->check = CSUM_MANGLED_0;
 168                         }
 169                 }
 170         }
 171
 172         csum_replace4(&nh->check, *addr, new_addr);
 173         skb_clear_hash(skb);
 174         *addr = new_addr;
 175 }
 176
 177 static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
 178                                  __be32 addr[4], const __be32 new_addr[4])
 179 {
 180         int transport_len = skb->len - skb_transport_offset(skb);
 181
 182         if (l4_proto == IPPROTO_TCP) {
 183                 if (likely(transport_len >= sizeof(struct tcphdr)))
 184                         inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
 185                                                   addr, new_addr, 1);
 186         } else if (l4_proto == IPPROTO_UDP) {
 187                 if (likely(transport_len >= sizeof(struct udphdr))) {
 188                         struct udphdr *uh = udp_hdr(skb);
 189
 190                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 191                                 inet_proto_csum_replace16(&uh->check, skb,
 192                                                           addr, new_addr, 1);
 193                                 if (!uh->check)
 194                                         uh->check = CSUM_MANGLED_0;
 195                         }
 196                 }
 197         }
 198 }
 199
 200 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 201                           __be32 addr[4], const __be32 new_addr[4],
 202                           bool recalculate_csum)
 203 {
 204         if (recalculate_csum)
 205                 update_ipv6_checksum(skb, l4_proto, addr, new_addr);
 206
 207         skb_clear_hash(skb);
 208         memcpy(addr, new_addr, sizeof(__be32[4]));
 209 }
 210
 211 static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
 212 {
 213         nh->priority = tc >> 4;
 214         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
 215 }
 216
 217 static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
 218 {
 219         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
 220         nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
 221         nh->flow_lbl[2] = fl & 0x000000FF;
 222 }
 223
 224 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
 225 {
 226         csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
 227         nh->ttl = new_ttl;
 228 }
 229
 230 static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
 231 {
 232         struct iphdr *nh;
 233         int err;
 234
 235         err = make_writable(skb, skb_network_offset(skb) +
 236                                  sizeof(struct iphdr));
 237         if (unlikely(err))
 238                 return err;
 239
 240         nh = ip_hdr(skb);
 241
 242         if (ipv4_key->ipv4_src != nh->saddr)
 243                 set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
 244
 245         if (ipv4_key->ipv4_dst != nh->daddr)
 246                 set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
 247
 248         if (ipv4_key->ipv4_tos != nh->tos)
 249                 ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
 250
 251         if (ipv4_key->ipv4_ttl != nh->ttl)
 252                 set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
 253
 254         return 0;
 255 }
 256
 257 static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
 258 {
 259         struct ipv6hdr *nh;
 260         int err;
 261         __be32 *saddr;
 262         __be32 *daddr;
 263
 264         err = make_writable(skb, skb_network_offset(skb) +
 265                             sizeof(struct ipv6hdr));
 266         if (unlikely(err))
 267                 return err;
 268
 269         nh = ipv6_hdr(skb);
 270         saddr = (__be32 *)&nh->saddr;
 271         daddr = (__be32 *)&nh->daddr;
 272
 273         if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
 274                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
 275                               ipv6_key->ipv6_src, true);
 276
 277         if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
 278                 unsigned int offset = 0;
 279                 int flags = IP6_FH_F_SKIP_RH;
 280                 bool recalc_csum = true;
 281
 282                 if (ipv6_ext_hdr(nh->nexthdr))
 283                         recalc_csum = ipv6_find_hdr(skb, &offset,
 284                                                     NEXTHDR_ROUTING, NULL,
 285                                                     &flags) != NEXTHDR_ROUTING;
 286
 287                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
 288                               ipv6_key->ipv6_dst, recalc_csum);
 289         }
 290
 291         set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
 292         set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
 293         nh->hop_limit = ipv6_key->ipv6_hlimit;
 294
 295         return 0;
 296 }
 297
 298 /* Must follow make_writable() since that can move the skb data. */
 299 static void set_tp_port(struct sk_buff *skb, __be16 *port,
 300                          __be16 new_port, __sum16 *check)
 301 {
 302         inet_proto_csum_replace2(check, skb, *port, new_port, 0);
 303         *port = new_port;
 304         skb_clear_hash(skb);
 305 }
 306
 307 static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
 308 {
 309         struct udphdr *uh = udp_hdr(skb);
 310
 311         if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
 312                 set_tp_port(skb, port, new_port, &uh->check);
 313
 314                 if (!uh->check)
 315                         uh->check = CSUM_MANGLED_0;
 316         } else {
 317                 *port = new_port;
 318                 skb_clear_hash(skb);
 319         }
 320 }
 321
 322 static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
 323 {
 324         struct udphdr *uh;
 325         int err;
 326
 327         err = make_writable(skb, skb_transport_offset(skb) +
 328                                  sizeof(struct udphdr));
 329         if (unlikely(err))
 330                 return err;
 331
 332         uh = udp_hdr(skb);
 333         if (udp_port_key->udp_src != uh->source)
 334                 set_udp_port(skb, &uh->source, udp_port_key->udp_src);
 335
 336         if (udp_port_key->udp_dst != uh->dest)
 337                 set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
 338
 339         return 0;
 340 }
 341
 342 static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 343 {
 344         struct tcphdr *th;
 345         int err;
 346
 347         err = make_writable(skb, skb_transport_offset(skb) +
 348                                  sizeof(struct tcphdr));
 349         if (unlikely(err))
 350                 return err;
 351
 352         th = tcp_hdr(skb);
 353         if (tcp_port_key->tcp_src != th->source)
 354                 set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
 355
 356         if (tcp_port_key->tcp_dst != th->dest)
 357                 set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
 358
 359         return 0;
 360 }
 361
 362 static int set_sctp(struct sk_buff *skb,
 363                      const struct ovs_key_sctp *sctp_port_key)
 364 {
 365         struct sctphdr *sh;
 366         int err;
 367         unsigned int sctphoff = skb_transport_offset(skb);
 368
 369         err = make_writable(skb, sctphoff + sizeof(struct sctphdr));
 370         if (unlikely(err))
 371                 return err;
 372
 373         sh = sctp_hdr(skb);
 374         if (sctp_port_key->sctp_src != sh->source ||
 375             sctp_port_key->sctp_dst != sh->dest) {
 376                 __le32 old_correct_csum, new_csum, old_csum;
 377
 378                 old_csum = sh->checksum;
 379                 old_correct_csum = sctp_compute_cksum(skb, sctphoff);
 380
 381                 sh->source = sctp_port_key->sctp_src;
 382                 sh->dest = sctp_port_key->sctp_dst;
 383
 384                 new_csum = sctp_compute_cksum(skb, sctphoff);
 385
 386                 /* Carry any checksum errors through. */
 387                 sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
 388
 389                 skb_clear_hash(skb);
 390         }
 391
 392         return 0;
 393 }
 394
 395 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 396 {
 397         struct vport *vport;
 398
 399         if (unlikely(!skb))
 400                 return -ENOMEM;
 401
 402         vport = ovs_vport_rcu(dp, out_port);
 403         if (unlikely(!vport)) {
 404                 kfree_skb(skb);
 405                 return -ENODEV;
 406         }
 407
 408         ovs_vport_send(vport, skb);
 409         return 0;
 410 }
 411
 412 static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 413                             const struct nlattr *attr)
 414 {
 415         struct dp_upcall_info upcall;
 416         const struct nlattr *a;
 417         int rem;
 418
 419         BUG_ON(!OVS_CB(skb)->pkt_key);
 420
 421         upcall.cmd = OVS_PACKET_CMD_ACTION;
 422         upcall.key = OVS_CB(skb)->pkt_key;
 423         upcall.userdata = NULL;
 424         upcall.portid = 0;
 425
 426         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 427                  a = nla_next(a, &rem)) {
 428                 switch (nla_type(a)) {
 429                 case OVS_USERSPACE_ATTR_USERDATA:
 430                         upcall.userdata = a;
 431                         break;
 432
 433                 case OVS_USERSPACE_ATTR_PID:
 434                         upcall.portid = nla_get_u32(a);
 435                         break;
 436                 }
 437         }
 438
 439         return ovs_dp_upcall(dp, skb, &upcall);
 440 }
 441
 442 static int sample(struct datapath *dp, struct sk_buff *skb,
 443                   const struct nlattr *attr)
 444 {
 445         const struct nlattr *acts_list = NULL;
 446         const struct nlattr *a;
 447         int rem;
 448
 449         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 450                  a = nla_next(a, &rem)) {
 451                 switch (nla_type(a)) {
 452                 case OVS_SAMPLE_ATTR_PROBABILITY:
 453                         if (prandom_u32() >= nla_get_u32(a))
 454                                 return 0;
 455                         break;
 456
 457                 case OVS_SAMPLE_ATTR_ACTIONS:
 458                         acts_list = a;
 459                         break;
 460                 }
 461         }
 462
 463         return do_execute_actions(dp, skb, nla_data(acts_list),
 464                                                  nla_len(acts_list), true);
 465 }
 466
 467 static int execute_set_action(struct sk_buff *skb,
 468                                  const struct nlattr *nested_attr)
 469 {
 470         int err = 0;
 471
 472         switch (nla_type(nested_attr)) {
 473         case OVS_KEY_ATTR_PRIORITY:
 474                 skb->priority = nla_get_u32(nested_attr);
 475                 break;
 476
 477         case OVS_KEY_ATTR_SKB_MARK:
 478                 skb->mark = nla_get_u32(nested_attr);
 479                 break;
 480
 481         case OVS_KEY_ATTR_IPV4_TUNNEL:
 482                 OVS_CB(skb)->tun_key = nla_data(nested_attr);
 483                 break;
 484
 485         case OVS_KEY_ATTR_ETHERNET:
 486                 err = set_eth_addr(skb, nla_data(nested_attr));
 487                 break;
 488
 489         case OVS_KEY_ATTR_IPV4:
 490                 err = set_ipv4(skb, nla_data(nested_attr));
 491                 break;
 492
 493         case OVS_KEY_ATTR_IPV6:
 494                 err = set_ipv6(skb, nla_data(nested_attr));
 495                 break;
 496
 497         case OVS_KEY_ATTR_TCP:
 498                 err = set_tcp(skb, nla_data(nested_attr));
 499                 break;
 500
 501         case OVS_KEY_ATTR_UDP:
 502                 err = set_udp(skb, nla_data(nested_attr));
 503                 break;
 504
 505         case OVS_KEY_ATTR_SCTP:
 506                 err = set_sctp(skb, nla_data(nested_attr));
 507                 break;
 508         }
 509
 510         return err;
 511 }
 512
 513 /* Execute a list of actions against 'skb'. */
 514 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 515                         const struct nlattr *attr, int len, bool keep_skb)
 516 {
 517         /* Every output action needs a separate clone of 'skb', but the common
 518          * case is just a single output action, so that doing a clone and
 519          * then freeing the original skbuff is wasteful.  So the following code
 520          * is slightly obscure just to avoid that. */
 521         int prev_port = -1;
 522         const struct nlattr *a;
 523         int rem;
 524
 525         for (a = attr, rem = len; rem > 0;
 526              a = nla_next(a, &rem)) {
 527                 int err = 0;
 528
 529                 if (prev_port != -1) {
 530                         do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
 531                         prev_port = -1;
 532                 }
 533
 534                 switch (nla_type(a)) {
 535                 case OVS_ACTION_ATTR_OUTPUT:
 536                         prev_port = nla_get_u32(a);
 537                         break;
 538
 539                 case OVS_ACTION_ATTR_USERSPACE:
 540                         output_userspace(dp, skb, a);
 541                         break;
 542
 543                 case OVS_ACTION_ATTR_PUSH_VLAN:
 544                         err = push_vlan(skb, nla_data(a));
 545                         if (unlikely(err)) /* skb already freed. */
 546                                 return err;
 547                         break;
 548
 549                 case OVS_ACTION_ATTR_POP_VLAN:
 550                         err = pop_vlan(skb);
 551                         break;
 552
 553                 case OVS_ACTION_ATTR_SET:
 554                         err = execute_set_action(skb, nla_data(a));
 555                         break;
 556
 557                 case OVS_ACTION_ATTR_SAMPLE:
 558                         err = sample(dp, skb, a);
 559                         break;
 560                 }
 561
 562                 if (unlikely(err)) {
 563                         kfree_skb(skb);
 564                         return err;
 565                 }
 566         }
 567
 568         if (prev_port != -1) {
 569                 if (keep_skb)
 570                         skb = skb_clone(skb, GFP_ATOMIC);
 571
 572                 do_output(dp, skb, prev_port);
 573         } else if (!keep_skb)
 574                 consume_skb(skb);
 575
 576         return 0;
 577 }
 578
 579 /* Execute a list of actions against 'skb'. */
 580 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
 581 {
 582         struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
 583
 584         OVS_CB(skb)->tun_key = NULL;
 585         return do_execute_actions(dp, skb, acts->actions,
 586                                          acts->actions_len, false);
 587 }