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