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