1 /* 2 * Copyright (c) 2007-2012 Nicira Networks. 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/checksum.h> 32 #include <net/dsfield.h> 33 34 #include "datapath.h" 35 #include "vport.h" 36 37 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, 38 const struct nlattr *attr, int len, bool keep_skb); 39 40 static int make_writable(struct sk_buff *skb, int write_len) 41 { 42 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len)) 43 return 0; 44 45 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 46 } 47 48 /* remove VLAN header from packet and update csum accrodingly. */ 49 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci) 50 { 51 struct vlan_hdr *vhdr; 52 int err; 53 54 err = make_writable(skb, VLAN_ETH_HLEN); 55 if (unlikely(err)) 56 return err; 57 58 if (skb->ip_summed == CHECKSUM_COMPLETE) 59 skb->csum = csum_sub(skb->csum, csum_partial(skb->data 60 + ETH_HLEN, VLAN_HLEN, 0)); 61 62 vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN); 63 *current_tci = vhdr->h_vlan_TCI; 64 65 memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN); 66 __skb_pull(skb, VLAN_HLEN); 67 68 vlan_set_encap_proto(skb, vhdr); 69 skb->mac_header += VLAN_HLEN; 70 skb_reset_mac_len(skb); 71 72 return 0; 73 } 74 75 static int pop_vlan(struct sk_buff *skb) 76 { 77 __be16 tci; 78 int err; 79 80 if (likely(vlan_tx_tag_present(skb))) { 81 skb->vlan_tci = 0; 82 } else { 83 if (unlikely(skb->protocol != htons(ETH_P_8021Q) || 84 skb->len < VLAN_ETH_HLEN)) 85 return 0; 86 87 err = __pop_vlan_tci(skb, &tci); 88 if (err) 89 return err; 90 } 91 /* move next vlan tag to hw accel tag */ 92 if (likely(skb->protocol != htons(ETH_P_8021Q) || 93 skb->len < VLAN_ETH_HLEN)) 94 return 0; 95 96 err = __pop_vlan_tci(skb, &tci); 97 if (unlikely(err)) 98 return err; 99 100 __vlan_hwaccel_put_tag(skb, ntohs(tci)); 101 return 0; 102 } 103 104 static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan) 105 { 106 if (unlikely(vlan_tx_tag_present(skb))) { 107 u16 current_tag; 108 109 /* push down current VLAN tag */ 110 current_tag = vlan_tx_tag_get(skb); 111 112 if (!__vlan_put_tag(skb, current_tag)) 113 return -ENOMEM; 114 115 if (skb->ip_summed == CHECKSUM_COMPLETE) 116 skb->csum = csum_add(skb->csum, csum_partial(skb->data 117 + ETH_HLEN, VLAN_HLEN, 0)); 118 119 } 120 __vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT); 121 return 0; 122 } 123 124 static int set_eth_addr(struct sk_buff *skb, 125 const struct ovs_key_ethernet *eth_key) 126 { 127 int err; 128 err = make_writable(skb, ETH_HLEN); 129 if (unlikely(err)) 130 return err; 131 132 memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN); 133 memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN); 134 135 return 0; 136 } 137 138 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh, 139 __be32 *addr, __be32 new_addr) 140 { 141 int transport_len = skb->len - skb_transport_offset(skb); 142 143 if (nh->protocol == IPPROTO_TCP) { 144 if (likely(transport_len >= sizeof(struct tcphdr))) 145 inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb, 146 *addr, new_addr, 1); 147 } else if (nh->protocol == IPPROTO_UDP) { 148 if (likely(transport_len >= sizeof(struct udphdr))) { 149 struct udphdr *uh = udp_hdr(skb); 150 151 if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) { 152 inet_proto_csum_replace4(&uh->check, skb, 153 *addr, new_addr, 1); 154 if (!uh->check) 155 uh->check = CSUM_MANGLED_0; 156 } 157 } 158 } 159 160 csum_replace4(&nh->check, *addr, new_addr); 161 skb->rxhash = 0; 162 *addr = new_addr; 163 } 164 165 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl) 166 { 167 csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8)); 168 nh->ttl = new_ttl; 169 } 170 171 static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key) 172 { 173 struct iphdr *nh; 174 int err; 175 176 err = make_writable(skb, skb_network_offset(skb) + 177 sizeof(struct iphdr)); 178 if (unlikely(err)) 179 return err; 180 181 nh = ip_hdr(skb); 182 183 if (ipv4_key->ipv4_src != nh->saddr) 184 set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src); 185 186 if (ipv4_key->ipv4_dst != nh->daddr) 187 set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst); 188 189 if (ipv4_key->ipv4_tos != nh->tos) 190 ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos); 191 192 if (ipv4_key->ipv4_ttl != nh->ttl) 193 set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl); 194 195 return 0; 196 } 197 198 /* Must follow make_writable() since that can move the skb data. */ 199 static void set_tp_port(struct sk_buff *skb, __be16 *port, 200 __be16 new_port, __sum16 *check) 201 { 202 inet_proto_csum_replace2(check, skb, *port, new_port, 0); 203 *port = new_port; 204 skb->rxhash = 0; 205 } 206 207 static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port) 208 { 209 struct udphdr *uh = udp_hdr(skb); 210 211 if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) { 212 set_tp_port(skb, port, new_port, &uh->check); 213 214 if (!uh->check) 215 uh->check = CSUM_MANGLED_0; 216 } else { 217 *port = new_port; 218 skb->rxhash = 0; 219 } 220 } 221 222 static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key) 223 { 224 struct udphdr *uh; 225 int err; 226 227 err = make_writable(skb, skb_transport_offset(skb) + 228 sizeof(struct udphdr)); 229 if (unlikely(err)) 230 return err; 231 232 uh = udp_hdr(skb); 233 if (udp_port_key->udp_src != uh->source) 234 set_udp_port(skb, &uh->source, udp_port_key->udp_src); 235 236 if (udp_port_key->udp_dst != uh->dest) 237 set_udp_port(skb, &uh->dest, udp_port_key->udp_dst); 238 239 return 0; 240 } 241 242 static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key) 243 { 244 struct tcphdr *th; 245 int err; 246 247 err = make_writable(skb, skb_transport_offset(skb) + 248 sizeof(struct tcphdr)); 249 if (unlikely(err)) 250 return err; 251 252 th = tcp_hdr(skb); 253 if (tcp_port_key->tcp_src != th->source) 254 set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check); 255 256 if (tcp_port_key->tcp_dst != th->dest) 257 set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check); 258 259 return 0; 260 } 261 262 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port) 263 { 264 struct vport *vport; 265 266 if (unlikely(!skb)) 267 return -ENOMEM; 268 269 vport = rcu_dereference(dp->ports[out_port]); 270 if (unlikely(!vport)) { 271 kfree_skb(skb); 272 return -ENODEV; 273 } 274 275 ovs_vport_send(vport, skb); 276 return 0; 277 } 278 279 static int output_userspace(struct datapath *dp, struct sk_buff *skb, 280 const struct nlattr *attr) 281 { 282 struct dp_upcall_info upcall; 283 const struct nlattr *a; 284 int rem; 285 286 upcall.cmd = OVS_PACKET_CMD_ACTION; 287 upcall.key = &OVS_CB(skb)->flow->key; 288 upcall.userdata = NULL; 289 upcall.pid = 0; 290 291 for (a = nla_data(attr), rem = nla_len(attr); rem > 0; 292 a = nla_next(a, &rem)) { 293 switch (nla_type(a)) { 294 case OVS_USERSPACE_ATTR_USERDATA: 295 upcall.userdata = a; 296 break; 297 298 case OVS_USERSPACE_ATTR_PID: 299 upcall.pid = nla_get_u32(a); 300 break; 301 } 302 } 303 304 return ovs_dp_upcall(dp, skb, &upcall); 305 } 306 307 static int sample(struct datapath *dp, struct sk_buff *skb, 308 const struct nlattr *attr) 309 { 310 const struct nlattr *acts_list = NULL; 311 const struct nlattr *a; 312 int rem; 313 314 for (a = nla_data(attr), rem = nla_len(attr); rem > 0; 315 a = nla_next(a, &rem)) { 316 switch (nla_type(a)) { 317 case OVS_SAMPLE_ATTR_PROBABILITY: 318 if (net_random() >= nla_get_u32(a)) 319 return 0; 320 break; 321 322 case OVS_SAMPLE_ATTR_ACTIONS: 323 acts_list = a; 324 break; 325 } 326 } 327 328 return do_execute_actions(dp, skb, nla_data(acts_list), 329 nla_len(acts_list), true); 330 } 331 332 static int execute_set_action(struct sk_buff *skb, 333 const struct nlattr *nested_attr) 334 { 335 int err = 0; 336 337 switch (nla_type(nested_attr)) { 338 case OVS_KEY_ATTR_PRIORITY: 339 skb->priority = nla_get_u32(nested_attr); 340 break; 341 342 case OVS_KEY_ATTR_ETHERNET: 343 err = set_eth_addr(skb, nla_data(nested_attr)); 344 break; 345 346 case OVS_KEY_ATTR_IPV4: 347 err = set_ipv4(skb, nla_data(nested_attr)); 348 break; 349 350 case OVS_KEY_ATTR_TCP: 351 err = set_tcp(skb, nla_data(nested_attr)); 352 break; 353 354 case OVS_KEY_ATTR_UDP: 355 err = set_udp(skb, nla_data(nested_attr)); 356 break; 357 } 358 359 return err; 360 } 361 362 /* Execute a list of actions against 'skb'. */ 363 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, 364 const struct nlattr *attr, int len, bool keep_skb) 365 { 366 /* Every output action needs a separate clone of 'skb', but the common 367 * case is just a single output action, so that doing a clone and 368 * then freeing the original skbuff is wasteful. So the following code 369 * is slightly obscure just to avoid that. */ 370 int prev_port = -1; 371 const struct nlattr *a; 372 int rem; 373 374 for (a = attr, rem = len; rem > 0; 375 a = nla_next(a, &rem)) { 376 int err = 0; 377 378 if (prev_port != -1) { 379 do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port); 380 prev_port = -1; 381 } 382 383 switch (nla_type(a)) { 384 case OVS_ACTION_ATTR_OUTPUT: 385 prev_port = nla_get_u32(a); 386 break; 387 388 case OVS_ACTION_ATTR_USERSPACE: 389 output_userspace(dp, skb, a); 390 break; 391 392 case OVS_ACTION_ATTR_PUSH_VLAN: 393 err = push_vlan(skb, nla_data(a)); 394 if (unlikely(err)) /* skb already freed. */ 395 return err; 396 break; 397 398 case OVS_ACTION_ATTR_POP_VLAN: 399 err = pop_vlan(skb); 400 break; 401 402 case OVS_ACTION_ATTR_SET: 403 err = execute_set_action(skb, nla_data(a)); 404 break; 405 406 case OVS_ACTION_ATTR_SAMPLE: 407 err = sample(dp, skb, a); 408 break; 409 } 410 411 if (unlikely(err)) { 412 kfree_skb(skb); 413 return err; 414 } 415 } 416 417 if (prev_port != -1) { 418 if (keep_skb) 419 skb = skb_clone(skb, GFP_ATOMIC); 420 421 do_output(dp, skb, prev_port); 422 } else if (!keep_skb) 423 consume_skb(skb); 424 425 return 0; 426 } 427 428 /* Execute a list of actions against 'skb'. */ 429 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb) 430 { 431 struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts); 432 433 return do_execute_actions(dp, skb, acts->actions, 434 acts->actions_len, false); 435 } 436