net/openvswitch/actions.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 #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/tcp.h>
  26 #include <linux/udp.h>
  27 #include <linux/in6.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/if_vlan.h>
  30 #include <net/ip.h>
  31 #include <net/ipv6.h>
  32 #include <net/checksum.h>
  33 #include <net/dsfield.h>
  34
  35 #include "datapath.h"
  36 #include "vport.h"
  37
  38 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
  39                         const struct nlattr *attr, int len, bool keep_skb);
  40
  41 static int make_writable(struct sk_buff *skb, int write_len)
  42 {
  43         if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
  44                 return 0;
  45
  46         return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
  47 }
  48
  49 /* remove VLAN header from packet and update csum accordingly. */
  50 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
  51 {
  52         struct vlan_hdr *vhdr;
  53         int err;
  54
  55         err = make_writable(skb, VLAN_ETH_HLEN);
  56         if (unlikely(err))
  57                 return err;
  58
  59         if (skb->ip_summed == CHECKSUM_COMPLETE)
  60                 skb->csum = csum_sub(skb->csum, csum_partial(skb->data
  61                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
  62
  63         vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
  64         *current_tci = vhdr->h_vlan_TCI;
  65
  66         memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
  67         __skb_pull(skb, VLAN_HLEN);
  68
  69         vlan_set_encap_proto(skb, vhdr);
  70         skb->mac_header += VLAN_HLEN;
  71         skb_reset_mac_len(skb);
  72
  73         return 0;
  74 }
  75
  76 static int pop_vlan(struct sk_buff *skb)
  77 {
  78         __be16 tci;
  79         int err;
  80
  81         if (likely(vlan_tx_tag_present(skb))) {
  82                 skb->vlan_tci = 0;
  83         } else {
  84                 if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
  85                              skb->len < VLAN_ETH_HLEN))
  86                         return 0;
  87
  88                 err = __pop_vlan_tci(skb, &tci);
  89                 if (err)
  90                         return err;
  91         }
  92         /* move next vlan tag to hw accel tag */
  93         if (likely(skb->protocol != htons(ETH_P_8021Q) ||
  94                    skb->len < VLAN_ETH_HLEN))
  95                 return 0;
  96
  97         err = __pop_vlan_tci(skb, &tci);
  98         if (unlikely(err))
  99                 return err;
 100
 101         __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), ntohs(tci));
 102         return 0;
 103 }
 104
 105 static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan)
 106 {
 107         if (unlikely(vlan_tx_tag_present(skb))) {
 108                 u16 current_tag;
 109
 110                 /* push down current VLAN tag */
 111                 current_tag = vlan_tx_tag_get(skb);
 112
 113                 if (!__vlan_put_tag(skb, skb->vlan_proto, current_tag))
 114                         return -ENOMEM;
 115
 116                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 117                         skb->csum = csum_add(skb->csum, csum_partial(skb->data
 118                                         + (2 * ETH_ALEN), VLAN_HLEN, 0));
 119
 120         }
 121         __vlan_hwaccel_put_tag(skb, vlan->vlan_tpid, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
 122         return 0;
 123 }
 124
 125 static int set_eth_addr(struct sk_buff *skb,
 126                         const struct ovs_key_ethernet *eth_key)
 127 {
 128         int err;
 129         err = make_writable(skb, ETH_HLEN);
 130         if (unlikely(err))
 131                 return err;
 132
 133         memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
 134         memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);
 135
 136         return 0;
 137 }
 138
 139 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
 140                                 __be32 *addr, __be32 new_addr)
 141 {
 142         int transport_len = skb->len - skb_transport_offset(skb);
 143
 144         if (nh->protocol == IPPROTO_TCP) {
 145                 if (likely(transport_len >= sizeof(struct tcphdr)))
 146                         inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
 147                                                  *addr, new_addr, 1);
 148         } else if (nh->protocol == IPPROTO_UDP) {
 149                 if (likely(transport_len >= sizeof(struct udphdr))) {
 150                         struct udphdr *uh = udp_hdr(skb);
 151
 152                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 153                                 inet_proto_csum_replace4(&uh->check, skb,
 154                                                          *addr, new_addr, 1);
 155                                 if (!uh->check)
 156                                         uh->check = CSUM_MANGLED_0;
 157                         }
 158                 }
 159         }
 160
 161         csum_replace4(&nh->check, *addr, new_addr);
 162         skb->rxhash = 0;
 163         *addr = new_addr;
 164 }
 165
 166 static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
 167                                  __be32 addr[4], const __be32 new_addr[4])
 168 {
 169         int transport_len = skb->len - skb_transport_offset(skb);
 170
 171         if (l4_proto == IPPROTO_TCP) {
 172                 if (likely(transport_len >= sizeof(struct tcphdr)))
 173                         inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
 174                                                   addr, new_addr, 1);
 175         } else if (l4_proto == IPPROTO_UDP) {
 176                 if (likely(transport_len >= sizeof(struct udphdr))) {
 177                         struct udphdr *uh = udp_hdr(skb);
 178
 179                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 180                                 inet_proto_csum_replace16(&uh->check, skb,
 181                                                           addr, new_addr, 1);
 182                                 if (!uh->check)
 183                                         uh->check = CSUM_MANGLED_0;
 184                         }
 185                 }
 186         }
 187 }
 188
 189 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 190                           __be32 addr[4], const __be32 new_addr[4],
 191                           bool recalculate_csum)
 192 {
 193         if (recalculate_csum)
 194                 update_ipv6_checksum(skb, l4_proto, addr, new_addr);
 195
 196         skb->rxhash = 0;
 197         memcpy(addr, new_addr, sizeof(__be32[4]));
 198 }
 199
 200 static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
 201 {
 202         nh->priority = tc >> 4;
 203         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
 204 }
 205
 206 static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
 207 {
 208         nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
 209         nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
 210         nh->flow_lbl[2] = fl & 0x000000FF;
 211 }
 212
 213 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
 214 {
 215         csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
 216         nh->ttl = new_ttl;
 217 }
 218
 219 static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
 220 {
 221         struct iphdr *nh;
 222         int err;
 223
 224         err = make_writable(skb, skb_network_offset(skb) +
 225                                  sizeof(struct iphdr));
 226         if (unlikely(err))
 227                 return err;
 228
 229         nh = ip_hdr(skb);
 230
 231         if (ipv4_key->ipv4_src != nh->saddr)
 232                 set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
 233
 234         if (ipv4_key->ipv4_dst != nh->daddr)
 235                 set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
 236
 237         if (ipv4_key->ipv4_tos != nh->tos)
 238                 ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
 239
 240         if (ipv4_key->ipv4_ttl != nh->ttl)
 241                 set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
 242
 243         return 0;
 244 }
 245
 246 static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
 247 {
 248         struct ipv6hdr *nh;
 249         int err;
 250         __be32 *saddr;
 251         __be32 *daddr;
 252
 253         err = make_writable(skb, skb_network_offset(skb) +
 254                             sizeof(struct ipv6hdr));
 255         if (unlikely(err))
 256                 return err;
 257
 258         nh = ipv6_hdr(skb);
 259         saddr = (__be32 *)&nh->saddr;
 260         daddr = (__be32 *)&nh->daddr;
 261
 262         if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
 263                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
 264                               ipv6_key->ipv6_src, true);
 265
 266         if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
 267                 unsigned int offset = 0;
 268                 int flags = IP6_FH_F_SKIP_RH;
 269                 bool recalc_csum = true;
 270
 271                 if (ipv6_ext_hdr(nh->nexthdr))
 272                         recalc_csum = ipv6_find_hdr(skb, &offset,
 273                                                     NEXTHDR_ROUTING, NULL,
 274                                                     &flags) != NEXTHDR_ROUTING;
 275
 276                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
 277                               ipv6_key->ipv6_dst, recalc_csum);
 278         }
 279
 280         set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
 281         set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
 282         nh->hop_limit = ipv6_key->ipv6_hlimit;
 283
 284         return 0;
 285 }
 286
 287 /* Must follow make_writable() since that can move the skb data. */
 288 static void set_tp_port(struct sk_buff *skb, __be16 *port,
 289                          __be16 new_port, __sum16 *check)
 290 {
 291         inet_proto_csum_replace2(check, skb, *port, new_port, 0);
 292         *port = new_port;
 293         skb->rxhash = 0;
 294 }
 295
 296 static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
 297 {
 298         struct udphdr *uh = udp_hdr(skb);
 299
 300         if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
 301                 set_tp_port(skb, port, new_port, &uh->check);
 302
 303                 if (!uh->check)
 304                         uh->check = CSUM_MANGLED_0;
 305         } else {
 306                 *port = new_port;
 307                 skb->rxhash = 0;
 308         }
 309 }
 310
 311 static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
 312 {
 313         struct udphdr *uh;
 314         int err;
 315
 316         err = make_writable(skb, skb_transport_offset(skb) +
 317                                  sizeof(struct udphdr));
 318         if (unlikely(err))
 319                 return err;
 320
 321         uh = udp_hdr(skb);
 322         if (udp_port_key->udp_src != uh->source)
 323                 set_udp_port(skb, &uh->source, udp_port_key->udp_src);
 324
 325         if (udp_port_key->udp_dst != uh->dest)
 326                 set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
 327
 328         return 0;
 329 }
 330
 331 static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 332 {
 333         struct tcphdr *th;
 334         int err;
 335
 336         err = make_writable(skb, skb_transport_offset(skb) +
 337                                  sizeof(struct tcphdr));
 338         if (unlikely(err))
 339                 return err;
 340
 341         th = tcp_hdr(skb);
 342         if (tcp_port_key->tcp_src != th->source)
 343                 set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
 344
 345         if (tcp_port_key->tcp_dst != th->dest)
 346                 set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
 347
 348         return 0;
 349 }
 350
 351 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 352 {
 353         struct vport *vport;
 354
 355         if (unlikely(!skb))
 356                 return -ENOMEM;
 357
 358         vport = ovs_vport_rcu(dp, out_port);
 359         if (unlikely(!vport)) {
 360                 kfree_skb(skb);
 361                 return -ENODEV;
 362         }
 363
 364         ovs_vport_send(vport, skb);
 365         return 0;
 366 }
 367
 368 static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 369                             const struct nlattr *attr)
 370 {
 371         struct dp_upcall_info upcall;
 372         const struct nlattr *a;
 373         int rem;
 374
 375         upcall.cmd = OVS_PACKET_CMD_ACTION;
 376         upcall.key = &OVS_CB(skb)->flow->key;
 377         upcall.userdata = NULL;
 378         upcall.portid = 0;
 379
 380         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 381                  a = nla_next(a, &rem)) {
 382                 switch (nla_type(a)) {
 383                 case OVS_USERSPACE_ATTR_USERDATA:
 384                         upcall.userdata = a;
 385                         break;
 386
 387                 case OVS_USERSPACE_ATTR_PID:
 388                         upcall.portid = nla_get_u32(a);
 389                         break;
 390                 }
 391         }
 392
 393         return ovs_dp_upcall(dp, skb, &upcall);
 394 }
 395
 396 static int sample(struct datapath *dp, struct sk_buff *skb,
 397                   const struct nlattr *attr)
 398 {
 399         const struct nlattr *acts_list = NULL;
 400         const struct nlattr *a;
 401         int rem;
 402
 403         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 404                  a = nla_next(a, &rem)) {
 405                 switch (nla_type(a)) {
 406                 case OVS_SAMPLE_ATTR_PROBABILITY:
 407                         if (net_random() >= nla_get_u32(a))
 408                                 return 0;
 409                         break;
 410
 411                 case OVS_SAMPLE_ATTR_ACTIONS:
 412                         acts_list = a;
 413                         break;
 414                 }
 415         }
 416
 417         return do_execute_actions(dp, skb, nla_data(acts_list),
 418                                                  nla_len(acts_list), true);
 419 }
 420
 421 static int execute_set_action(struct sk_buff *skb,
 422                                  const struct nlattr *nested_attr)
 423 {
 424         int err = 0;
 425
 426         switch (nla_type(nested_attr)) {
 427         case OVS_KEY_ATTR_PRIORITY:
 428                 skb->priority = nla_get_u32(nested_attr);
 429                 break;
 430
 431         case OVS_KEY_ATTR_SKB_MARK:
 432                 skb->mark = nla_get_u32(nested_attr);
 433                 break;
 434
 435         case OVS_KEY_ATTR_ETHERNET:
 436                 err = set_eth_addr(skb, nla_data(nested_attr));
 437                 break;
 438
 439         case OVS_KEY_ATTR_IPV4:
 440                 err = set_ipv4(skb, nla_data(nested_attr));
 441                 break;
 442
 443         case OVS_KEY_ATTR_IPV6:
 444                 err = set_ipv6(skb, nla_data(nested_attr));
 445                 break;
 446
 447         case OVS_KEY_ATTR_TCP:
 448                 err = set_tcp(skb, nla_data(nested_attr));
 449                 break;
 450
 451         case OVS_KEY_ATTR_UDP:
 452                 err = set_udp(skb, nla_data(nested_attr));
 453                 break;
 454         }
 455
 456         return err;
 457 }
 458
 459 /* Execute a list of actions against 'skb'. */
 460 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 461                         const struct nlattr *attr, int len, bool keep_skb)
 462 {
 463         /* Every output action needs a separate clone of 'skb', but the common
 464          * case is just a single output action, so that doing a clone and
 465          * then freeing the original skbuff is wasteful.  So the following code
 466          * is slightly obscure just to avoid that. */
 467         int prev_port = -1;
 468         const struct nlattr *a;
 469         int rem;
 470
 471         for (a = attr, rem = len; rem > 0;
 472              a = nla_next(a, &rem)) {
 473                 int err = 0;
 474
 475                 if (prev_port != -1) {
 476                         do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
 477                         prev_port = -1;
 478                 }
 479
 480                 switch (nla_type(a)) {
 481                 case OVS_ACTION_ATTR_OUTPUT:
 482                         prev_port = nla_get_u32(a);
 483                         break;
 484
 485                 case OVS_ACTION_ATTR_USERSPACE:
 486                         output_userspace(dp, skb, a);
 487                         break;
 488
 489                 case OVS_ACTION_ATTR_PUSH_VLAN:
 490                         err = push_vlan(skb, nla_data(a));
 491                         if (unlikely(err)) /* skb already freed. */
 492                                 return err;
 493                         break;
 494
 495                 case OVS_ACTION_ATTR_POP_VLAN:
 496                         err = pop_vlan(skb);
 497                         break;
 498
 499                 case OVS_ACTION_ATTR_SET:
 500                         err = execute_set_action(skb, nla_data(a));
 501                         break;
 502
 503                 case OVS_ACTION_ATTR_SAMPLE:
 504                         err = sample(dp, skb, a);
 505                         break;
 506                 }
 507
 508                 if (unlikely(err)) {
 509                         kfree_skb(skb);
 510                         return err;
 511                 }
 512         }
 513
 514         if (prev_port != -1) {
 515                 if (keep_skb)
 516                         skb = skb_clone(skb, GFP_ATOMIC);
 517
 518                 do_output(dp, skb, prev_port);
 519         } else if (!keep_skb)
 520                 consume_skb(skb);
 521
 522         return 0;
 523 }
 524
 525 /* Execute a list of actions against 'skb'. */
 526 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
 527 {
 528         struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
 529
 530         return do_execute_actions(dp, skb, acts->actions,
 531                                          acts->actions_len, false);
 532 }