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 17 /* copy saddr & daddr, possibly using 64bit load/store 18 * Equivalent to : flow->src = iph->saddr; 19 * flow->dst = iph->daddr; 20 */ 21 static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph) 22 { 23 BUILD_BUG_ON(offsetof(typeof(*flow), dst) != 24 offsetof(typeof(*flow), src) + sizeof(flow->src)); 25 memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst)); 26 } 27 28 /** 29 * skb_flow_get_ports - extract the upper layer ports and return them 30 * @skb: buffer to extract the ports from 31 * @thoff: transport header offset 32 * @ip_proto: protocol for which to get port offset 33 * 34 * The function will try to retrieve the ports at offset thoff + poff where poff 35 * is the protocol port offset returned from proto_ports_offset 36 */ 37 __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto) 38 { 39 int poff = proto_ports_offset(ip_proto); 40 41 if (poff >= 0) { 42 __be32 *ports, _ports; 43 44 ports = skb_header_pointer(skb, thoff + poff, 45 sizeof(_ports), &_ports); 46 if (ports) 47 return *ports; 48 } 49 50 return 0; 51 } 52 EXPORT_SYMBOL(skb_flow_get_ports); 53 54 bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) 55 { 56 int nhoff = skb_network_offset(skb); 57 u8 ip_proto; 58 __be16 proto = skb->protocol; 59 60 memset(flow, 0, sizeof(*flow)); 61 62 again: 63 switch (proto) { 64 case htons(ETH_P_IP): { 65 const struct iphdr *iph; 66 struct iphdr _iph; 67 ip: 68 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); 69 if (!iph || iph->ihl < 5) 70 return false; 71 nhoff += iph->ihl * 4; 72 73 ip_proto = iph->protocol; 74 if (ip_is_fragment(iph)) 75 ip_proto = 0; 76 77 iph_to_flow_copy_addrs(flow, iph); 78 break; 79 } 80 case htons(ETH_P_IPV6): { 81 const struct ipv6hdr *iph; 82 struct ipv6hdr _iph; 83 ipv6: 84 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); 85 if (!iph) 86 return false; 87 88 ip_proto = iph->nexthdr; 89 flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr); 90 flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr); 91 nhoff += sizeof(struct ipv6hdr); 92 break; 93 } 94 case htons(ETH_P_8021AD): 95 case htons(ETH_P_8021Q): { 96 const struct vlan_hdr *vlan; 97 struct vlan_hdr _vlan; 98 99 vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan); 100 if (!vlan) 101 return false; 102 103 proto = vlan->h_vlan_encapsulated_proto; 104 nhoff += sizeof(*vlan); 105 goto again; 106 } 107 case htons(ETH_P_PPP_SES): { 108 struct { 109 struct pppoe_hdr hdr; 110 __be16 proto; 111 } *hdr, _hdr; 112 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 113 if (!hdr) 114 return false; 115 proto = hdr->proto; 116 nhoff += PPPOE_SES_HLEN; 117 switch (proto) { 118 case htons(PPP_IP): 119 goto ip; 120 case htons(PPP_IPV6): 121 goto ipv6; 122 default: 123 return false; 124 } 125 } 126 default: 127 return false; 128 } 129 130 switch (ip_proto) { 131 case IPPROTO_GRE: { 132 struct gre_hdr { 133 __be16 flags; 134 __be16 proto; 135 } *hdr, _hdr; 136 137 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 138 if (!hdr) 139 return false; 140 /* 141 * Only look inside GRE if version zero and no 142 * routing 143 */ 144 if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) { 145 proto = hdr->proto; 146 nhoff += 4; 147 if (hdr->flags & GRE_CSUM) 148 nhoff += 4; 149 if (hdr->flags & GRE_KEY) 150 nhoff += 4; 151 if (hdr->flags & GRE_SEQ) 152 nhoff += 4; 153 if (proto == htons(ETH_P_TEB)) { 154 const struct ethhdr *eth; 155 struct ethhdr _eth; 156 157 eth = skb_header_pointer(skb, nhoff, 158 sizeof(_eth), &_eth); 159 if (!eth) 160 return false; 161 proto = eth->h_proto; 162 nhoff += sizeof(*eth); 163 } 164 goto again; 165 } 166 break; 167 } 168 case IPPROTO_IPIP: 169 proto = htons(ETH_P_IP); 170 goto ip; 171 case IPPROTO_IPV6: 172 proto = htons(ETH_P_IPV6); 173 goto ipv6; 174 default: 175 break; 176 } 177 178 flow->ip_proto = ip_proto; 179 flow->ports = skb_flow_get_ports(skb, nhoff, ip_proto); 180 flow->thoff = (u16) nhoff; 181 182 return true; 183 } 184 EXPORT_SYMBOL(skb_flow_dissect); 185 186 static u32 hashrnd __read_mostly; 187 static __always_inline void __flow_hash_secret_init(void) 188 { 189 net_get_random_once(&hashrnd, sizeof(hashrnd)); 190 } 191 192 static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c) 193 { 194 __flow_hash_secret_init(); 195 return jhash_3words(a, b, c, hashrnd); 196 } 197 198 static __always_inline u32 __flow_hash_1word(u32 a) 199 { 200 __flow_hash_secret_init(); 201 return jhash_1word(a, hashrnd); 202 } 203 204 /* 205 * __skb_get_hash: calculate a flow hash based on src/dst addresses 206 * and src/dst port numbers. Sets hash in skb to non-zero hash value 207 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 208 * if hash is a canonical 4-tuple hash over transport ports. 209 */ 210 void __skb_get_hash(struct sk_buff *skb) 211 { 212 struct flow_keys keys; 213 u32 hash; 214 215 if (!skb_flow_dissect(skb, &keys)) 216 return; 217 218 if (keys.ports) 219 skb->l4_hash = 1; 220 221 /* get a consistent hash (same value on both flow directions) */ 222 if (((__force u32)keys.dst < (__force u32)keys.src) || 223 (((__force u32)keys.dst == (__force u32)keys.src) && 224 ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { 225 swap(keys.dst, keys.src); 226 swap(keys.port16[0], keys.port16[1]); 227 } 228 229 hash = __flow_hash_3words((__force u32)keys.dst, 230 (__force u32)keys.src, 231 (__force u32)keys.ports); 232 if (!hash) 233 hash = 1; 234 235 skb->hash = hash; 236 } 237 EXPORT_SYMBOL(__skb_get_hash); 238 239 /* 240 * Returns a Tx hash based on the given packet descriptor a Tx queues' number 241 * to be used as a distribution range. 242 */ 243 u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb, 244 unsigned int num_tx_queues) 245 { 246 u32 hash; 247 u16 qoffset = 0; 248 u16 qcount = num_tx_queues; 249 250 if (skb_rx_queue_recorded(skb)) { 251 hash = skb_get_rx_queue(skb); 252 while (unlikely(hash >= num_tx_queues)) 253 hash -= num_tx_queues; 254 return hash; 255 } 256 257 if (dev->num_tc) { 258 u8 tc = netdev_get_prio_tc_map(dev, skb->priority); 259 qoffset = dev->tc_to_txq[tc].offset; 260 qcount = dev->tc_to_txq[tc].count; 261 } 262 263 if (skb->sk && skb->sk->sk_hash) 264 hash = skb->sk->sk_hash; 265 else 266 hash = (__force u16) skb->protocol; 267 hash = __flow_hash_1word(hash); 268 269 return (u16) (((u64) hash * qcount) >> 32) + qoffset; 270 } 271 EXPORT_SYMBOL(__skb_tx_hash); 272 273 /* __skb_get_poff() returns the offset to the payload as far as it could 274 * be dissected. The main user is currently BPF, so that we can dynamically 275 * truncate packets without needing to push actual payload to the user 276 * space and can analyze headers only, instead. 277 */ 278 u32 __skb_get_poff(const struct sk_buff *skb) 279 { 280 struct flow_keys keys; 281 u32 poff = 0; 282 283 if (!skb_flow_dissect(skb, &keys)) 284 return 0; 285 286 poff += keys.thoff; 287 switch (keys.ip_proto) { 288 case IPPROTO_TCP: { 289 const struct tcphdr *tcph; 290 struct tcphdr _tcph; 291 292 tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph); 293 if (!tcph) 294 return poff; 295 296 poff += max_t(u32, sizeof(struct tcphdr), tcph->doff * 4); 297 break; 298 } 299 case IPPROTO_UDP: 300 case IPPROTO_UDPLITE: 301 poff += sizeof(struct udphdr); 302 break; 303 /* For the rest, we do not really care about header 304 * extensions at this point for now. 305 */ 306 case IPPROTO_ICMP: 307 poff += sizeof(struct icmphdr); 308 break; 309 case IPPROTO_ICMPV6: 310 poff += sizeof(struct icmp6hdr); 311 break; 312 case IPPROTO_IGMP: 313 poff += sizeof(struct igmphdr); 314 break; 315 case IPPROTO_DCCP: 316 poff += sizeof(struct dccp_hdr); 317 break; 318 case IPPROTO_SCTP: 319 poff += sizeof(struct sctphdr); 320 break; 321 } 322 323 return poff; 324 } 325 326 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) 327 { 328 #ifdef CONFIG_XPS 329 struct xps_dev_maps *dev_maps; 330 struct xps_map *map; 331 int queue_index = -1; 332 333 rcu_read_lock(); 334 dev_maps = rcu_dereference(dev->xps_maps); 335 if (dev_maps) { 336 map = rcu_dereference( 337 dev_maps->cpu_map[raw_smp_processor_id()]); 338 if (map) { 339 if (map->len == 1) 340 queue_index = map->queues[0]; 341 else { 342 u32 hash; 343 if (skb->sk && skb->sk->sk_hash) 344 hash = skb->sk->sk_hash; 345 else 346 hash = (__force u16) skb->protocol ^ 347 skb->hash; 348 hash = __flow_hash_1word(hash); 349 queue_index = map->queues[ 350 ((u64)hash * map->len) >> 32]; 351 } 352 if (unlikely(queue_index >= dev->real_num_tx_queues)) 353 queue_index = -1; 354 } 355 } 356 rcu_read_unlock(); 357 358 return queue_index; 359 #else 360 return -1; 361 #endif 362 } 363 364 static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb) 365 { 366 struct sock *sk = skb->sk; 367 int queue_index = sk_tx_queue_get(sk); 368 369 if (queue_index < 0 || skb->ooo_okay || 370 queue_index >= dev->real_num_tx_queues) { 371 int new_index = get_xps_queue(dev, skb); 372 if (new_index < 0) 373 new_index = skb_tx_hash(dev, skb); 374 375 if (queue_index != new_index && sk && 376 rcu_access_pointer(sk->sk_dst_cache)) 377 sk_tx_queue_set(sk, new_index); 378 379 queue_index = new_index; 380 } 381 382 return queue_index; 383 } 384 385 struct netdev_queue *netdev_pick_tx(struct net_device *dev, 386 struct sk_buff *skb, 387 void *accel_priv) 388 { 389 int queue_index = 0; 390 391 if (dev->real_num_tx_queues != 1) { 392 const struct net_device_ops *ops = dev->netdev_ops; 393 if (ops->ndo_select_queue) 394 queue_index = ops->ndo_select_queue(dev, skb, accel_priv, 395 __netdev_pick_tx); 396 else 397 queue_index = __netdev_pick_tx(dev, skb); 398 399 if (!accel_priv) 400 queue_index = netdev_cap_txqueue(dev, queue_index); 401 } 402 403 skb_set_queue_mapping(skb, queue_index); 404 return netdev_get_tx_queue(dev, queue_index); 405 } 406