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 } 533