1 #include <linux/skbuff.h> 2 #include <linux/export.h> 3 #include <linux/ip.h> 4 #include <linux/ipv6.h> 5 #include <linux/if_vlan.h> 6 #include <net/ip.h> 7 #include <net/ipv6.h> 8 #include <linux/igmp.h> 9 #include <linux/icmp.h> 10 #include <linux/sctp.h> 11 #include <linux/dccp.h> 12 #include <linux/if_tunnel.h> 13 #include <linux/if_pppox.h> 14 #include <linux/ppp_defs.h> 15 #include <net/flow_keys.h> 16 #include <scsi/fc/fc_fcoe.h> 17 18 /* copy saddr & daddr, possibly using 64bit load/store 19 * Equivalent to : flow->src = iph->saddr; 20 * flow->dst = iph->daddr; 21 */ 22 static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph) 23 { 24 BUILD_BUG_ON(offsetof(typeof(*flow), dst) != 25 offsetof(typeof(*flow), src) + sizeof(flow->src)); 26 memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst)); 27 } 28 29 /** 30 * __skb_flow_get_ports - extract the upper layer ports and return them 31 * @skb: sk_buff to extract the ports from 32 * @thoff: transport header offset 33 * @ip_proto: protocol for which to get port offset 34 * @data: raw buffer pointer to the packet, if NULL use skb->data 35 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 36 * 37 * The function will try to retrieve the ports at offset thoff + poff where poff 38 * is the protocol port offset returned from proto_ports_offset 39 */ 40 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 41 void *data, int hlen) 42 { 43 int poff = proto_ports_offset(ip_proto); 44 45 if (!data) { 46 data = skb->data; 47 hlen = skb_headlen(skb); 48 } 49 50 if (poff >= 0) { 51 __be32 *ports, _ports; 52 53 ports = __skb_header_pointer(skb, thoff + poff, 54 sizeof(_ports), data, hlen, &_ports); 55 if (ports) 56 return *ports; 57 } 58 59 return 0; 60 } 61 EXPORT_SYMBOL(__skb_flow_get_ports); 62 63 /** 64 * __skb_flow_dissect - extract the flow_keys struct and return it 65 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified 66 * @data: raw buffer pointer to the packet, if NULL use skb->data 67 * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol 68 * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb) 69 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 70 * 71 * The function will try to retrieve the struct flow_keys from either the skbuff 72 * or a raw buffer specified by the rest parameters 73 */ 74 bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow, 75 void *data, __be16 proto, int nhoff, int hlen) 76 { 77 u8 ip_proto; 78 79 if (!data) { 80 data = skb->data; 81 proto = skb->protocol; 82 nhoff = skb_network_offset(skb); 83 hlen = skb_headlen(skb); 84 } 85 86 memset(flow, 0, sizeof(*flow)); 87 88 again: 89 switch (proto) { 90 case htons(ETH_P_IP): { 91 const struct iphdr *iph; 92 struct iphdr _iph; 93 ip: 94 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 95 if (!iph || iph->ihl < 5) 96 return false; 97 nhoff += iph->ihl * 4; 98 99 ip_proto = iph->protocol; 100 if (ip_is_fragment(iph)) 101 ip_proto = 0; 102 103 /* skip the address processing if skb is NULL. The assumption 104 * here is that if there is no skb we are not looking for flow 105 * info but lengths and protocols. 106 */ 107 if (!skb) 108 break; 109 110 iph_to_flow_copy_addrs(flow, iph); 111 break; 112 } 113 case htons(ETH_P_IPV6): { 114 const struct ipv6hdr *iph; 115 struct ipv6hdr _iph; 116 __be32 flow_label; 117 118 ipv6: 119 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 120 if (!iph) 121 return false; 122 123 ip_proto = iph->nexthdr; 124 nhoff += sizeof(struct ipv6hdr); 125 126 /* see comment above in IPv4 section */ 127 if (!skb) 128 break; 129 130 flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr); 131 flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr); 132 133 flow_label = ip6_flowlabel(iph); 134 if (flow_label) { 135 /* Awesome, IPv6 packet has a flow label so we can 136 * use that to represent the ports without any 137 * further dissection. 138 */ 139 flow->n_proto = proto; 140 flow->ip_proto = ip_proto; 141 flow->ports = flow_label; 142 flow->thoff = (u16)nhoff; 143 144 return true; 145 } 146 147 break; 148 } 149 case htons(ETH_P_8021AD): 150 case htons(ETH_P_8021Q): { 151 const struct vlan_hdr *vlan; 152 struct vlan_hdr _vlan; 153 154 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan); 155 if (!vlan) 156 return false; 157 158 proto = vlan->h_vlan_encapsulated_proto; 159 nhoff += sizeof(*vlan); 160 goto again; 161 } 162 case htons(ETH_P_PPP_SES): { 163 struct { 164 struct pppoe_hdr hdr; 165 __be16 proto; 166 } *hdr, _hdr; 167 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 168 if (!hdr) 169 return false; 170 proto = hdr->proto; 171 nhoff += PPPOE_SES_HLEN; 172 switch (proto) { 173 case htons(PPP_IP): 174 goto ip; 175 case htons(PPP_IPV6): 176 goto ipv6; 177 default: 178 return false; 179 } 180 } 181 case htons(ETH_P_FCOE): 182 flow->thoff = (u16)(nhoff + FCOE_HEADER_LEN); 183 /* fall through */ 184 default: 185 return false; 186 } 187 188 switch (ip_proto) { 189 case IPPROTO_GRE: { 190 struct gre_hdr { 191 __be16 flags; 192 __be16 proto; 193 } *hdr, _hdr; 194 195 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 196 if (!hdr) 197 return false; 198 /* 199 * Only look inside GRE if version zero and no 200 * routing 201 */ 202 if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) { 203 proto = hdr->proto; 204 nhoff += 4; 205 if (hdr->flags & GRE_CSUM) 206 nhoff += 4; 207 if (hdr->flags & GRE_KEY) 208 nhoff += 4; 209 if (hdr->flags & GRE_SEQ) 210 nhoff += 4; 211 if (proto == htons(ETH_P_TEB)) { 212 const struct ethhdr *eth; 213 struct ethhdr _eth; 214 215 eth = __skb_header_pointer(skb, nhoff, 216 sizeof(_eth), 217 data, hlen, &_eth); 218 if (!eth) 219 return false; 220 proto = eth->h_proto; 221 nhoff += sizeof(*eth); 222 } 223 goto again; 224 } 225 break; 226 } 227 case IPPROTO_IPIP: 228 proto = htons(ETH_P_IP); 229 goto ip; 230 case IPPROTO_IPV6: 231 proto = htons(ETH_P_IPV6); 232 goto ipv6; 233 default: 234 break; 235 } 236 237 flow->n_proto = proto; 238 flow->ip_proto = ip_proto; 239 flow->thoff = (u16) nhoff; 240 241 /* unless skb is set we don't need to record port info */ 242 if (skb) 243 flow->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 244 data, hlen); 245 246 return true; 247 } 248 EXPORT_SYMBOL(__skb_flow_dissect); 249 250 static u32 hashrnd __read_mostly; 251 static __always_inline void __flow_hash_secret_init(void) 252 { 253 net_get_random_once(&hashrnd, sizeof(hashrnd)); 254 } 255 256 static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c) 257 { 258 __flow_hash_secret_init(); 259 return jhash_3words(a, b, c, hashrnd); 260 } 261 262 static inline u32 __flow_hash_from_keys(struct flow_keys *keys) 263 { 264 u32 hash; 265 266 /* get a consistent hash (same value on both flow directions) */ 267 if (((__force u32)keys->dst < (__force u32)keys->src) || 268 (((__force u32)keys->dst == (__force u32)keys->src) && 269 ((__force u16)keys->port16[1] < (__force u16)keys->port16[0]))) { 270 swap(keys->dst, keys->src); 271 swap(keys->port16[0], keys->port16[1]); 272 } 273 274 hash = __flow_hash_3words((__force u32)keys->dst, 275 (__force u32)keys->src, 276 (__force u32)keys->ports); 277 if (!hash) 278 hash = 1; 279 280 return hash; 281 } 282 283 u32 flow_hash_from_keys(struct flow_keys *keys) 284 { 285 return __flow_hash_from_keys(keys); 286 } 287 EXPORT_SYMBOL(flow_hash_from_keys); 288 289 /* 290 * __skb_get_hash: calculate a flow hash based on src/dst addresses 291 * and src/dst port numbers. Sets hash in skb to non-zero hash value 292 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 293 * if hash is a canonical 4-tuple hash over transport ports. 294 */ 295 void __skb_get_hash(struct sk_buff *skb) 296 { 297 struct flow_keys keys; 298 299 if (!skb_flow_dissect(skb, &keys)) 300 return; 301 302 if (keys.ports) 303 skb->l4_hash = 1; 304 305 skb->sw_hash = 1; 306 307 skb->hash = __flow_hash_from_keys(&keys); 308 } 309 EXPORT_SYMBOL(__skb_get_hash); 310 311 /* 312 * Returns a Tx hash based on the given packet descriptor a Tx queues' number 313 * to be used as a distribution range. 314 */ 315 u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb, 316 unsigned int num_tx_queues) 317 { 318 u32 hash; 319 u16 qoffset = 0; 320 u16 qcount = num_tx_queues; 321 322 if (skb_rx_queue_recorded(skb)) { 323 hash = skb_get_rx_queue(skb); 324 while (unlikely(hash >= num_tx_queues)) 325 hash -= num_tx_queues; 326 return hash; 327 } 328 329 if (dev->num_tc) { 330 u8 tc = netdev_get_prio_tc_map(dev, skb->priority); 331 qoffset = dev->tc_to_txq[tc].offset; 332 qcount = dev->tc_to_txq[tc].count; 333 } 334 335 return (u16) reciprocal_scale(skb_get_hash(skb), qcount) + qoffset; 336 } 337 EXPORT_SYMBOL(__skb_tx_hash); 338 339 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 340 const struct flow_keys *keys, int hlen) 341 { 342 u32 poff = keys->thoff; 343 344 switch (keys->ip_proto) { 345 case IPPROTO_TCP: { 346 /* access doff as u8 to avoid unaligned access */ 347 const u8 *doff; 348 u8 _doff; 349 350 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 351 data, hlen, &_doff); 352 if (!doff) 353 return poff; 354 355 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 356 break; 357 } 358 case IPPROTO_UDP: 359 case IPPROTO_UDPLITE: 360 poff += sizeof(struct udphdr); 361 break; 362 /* For the rest, we do not really care about header 363 * extensions at this point for now. 364 */ 365 case IPPROTO_ICMP: 366 poff += sizeof(struct icmphdr); 367 break; 368 case IPPROTO_ICMPV6: 369 poff += sizeof(struct icmp6hdr); 370 break; 371 case IPPROTO_IGMP: 372 poff += sizeof(struct igmphdr); 373 break; 374 case IPPROTO_DCCP: 375 poff += sizeof(struct dccp_hdr); 376 break; 377 case IPPROTO_SCTP: 378 poff += sizeof(struct sctphdr); 379 break; 380 } 381 382 return poff; 383 } 384 385 /* skb_get_poff() returns the offset to the payload as far as it could 386 * be dissected. The main user is currently BPF, so that we can dynamically 387 * truncate packets without needing to push actual payload to the user 388 * space and can analyze headers only, instead. 389 */ 390 u32 skb_get_poff(const struct sk_buff *skb) 391 { 392 struct flow_keys keys; 393 394 if (!skb_flow_dissect(skb, &keys)) 395 return 0; 396 397 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 398 } 399 400 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) 401 { 402 #ifdef CONFIG_XPS 403 struct xps_dev_maps *dev_maps; 404 struct xps_map *map; 405 int queue_index = -1; 406 407 rcu_read_lock(); 408 dev_maps = rcu_dereference(dev->xps_maps); 409 if (dev_maps) { 410 map = rcu_dereference( 411 dev_maps->cpu_map[raw_smp_processor_id()]); 412 if (map) { 413 if (map->len == 1) 414 queue_index = map->queues[0]; 415 else 416 queue_index = map->queues[reciprocal_scale(skb_get_hash(skb), 417 map->len)]; 418 if (unlikely(queue_index >= dev->real_num_tx_queues)) 419 queue_index = -1; 420 } 421 } 422 rcu_read_unlock(); 423 424 return queue_index; 425 #else 426 return -1; 427 #endif 428 } 429 430 static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb) 431 { 432 struct sock *sk = skb->sk; 433 int queue_index = sk_tx_queue_get(sk); 434 435 if (queue_index < 0 || skb->ooo_okay || 436 queue_index >= dev->real_num_tx_queues) { 437 int new_index = get_xps_queue(dev, skb); 438 if (new_index < 0) 439 new_index = skb_tx_hash(dev, skb); 440 441 if (queue_index != new_index && sk && 442 rcu_access_pointer(sk->sk_dst_cache)) 443 sk_tx_queue_set(sk, new_index); 444 445 queue_index = new_index; 446 } 447 448 return queue_index; 449 } 450 451 struct netdev_queue *netdev_pick_tx(struct net_device *dev, 452 struct sk_buff *skb, 453 void *accel_priv) 454 { 455 int queue_index = 0; 456 457 if (dev->real_num_tx_queues != 1) { 458 const struct net_device_ops *ops = dev->netdev_ops; 459 if (ops->ndo_select_queue) 460 queue_index = ops->ndo_select_queue(dev, skb, accel_priv, 461 __netdev_pick_tx); 462 else 463 queue_index = __netdev_pick_tx(dev, skb); 464 465 if (!accel_priv) 466 queue_index = netdev_cap_txqueue(dev, queue_index); 467 } 468 469 skb_set_queue_mapping(skb, queue_index); 470 return netdev_get_tx_queue(dev, queue_index); 471 } 472