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 bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) 29 { 30 int poff, nhoff = skb_network_offset(skb); 31 u8 ip_proto; 32 __be16 proto = skb->protocol; 33 34 memset(flow, 0, sizeof(*flow)); 35 36 again: 37 switch (proto) { 38 case __constant_htons(ETH_P_IP): { 39 const struct iphdr *iph; 40 struct iphdr _iph; 41 ip: 42 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); 43 if (!iph) 44 return false; 45 46 if (ip_is_fragment(iph)) 47 ip_proto = 0; 48 else 49 ip_proto = iph->protocol; 50 iph_to_flow_copy_addrs(flow, iph); 51 nhoff += iph->ihl * 4; 52 break; 53 } 54 case __constant_htons(ETH_P_IPV6): { 55 const struct ipv6hdr *iph; 56 struct ipv6hdr _iph; 57 ipv6: 58 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); 59 if (!iph) 60 return false; 61 62 ip_proto = iph->nexthdr; 63 flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr); 64 flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr); 65 nhoff += sizeof(struct ipv6hdr); 66 break; 67 } 68 case __constant_htons(ETH_P_8021Q): { 69 const struct vlan_hdr *vlan; 70 struct vlan_hdr _vlan; 71 72 vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan); 73 if (!vlan) 74 return false; 75 76 proto = vlan->h_vlan_encapsulated_proto; 77 nhoff += sizeof(*vlan); 78 goto again; 79 } 80 case __constant_htons(ETH_P_PPP_SES): { 81 struct { 82 struct pppoe_hdr hdr; 83 __be16 proto; 84 } *hdr, _hdr; 85 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 86 if (!hdr) 87 return false; 88 proto = hdr->proto; 89 nhoff += PPPOE_SES_HLEN; 90 switch (proto) { 91 case __constant_htons(PPP_IP): 92 goto ip; 93 case __constant_htons(PPP_IPV6): 94 goto ipv6; 95 default: 96 return false; 97 } 98 } 99 default: 100 return false; 101 } 102 103 switch (ip_proto) { 104 case IPPROTO_GRE: { 105 struct gre_hdr { 106 __be16 flags; 107 __be16 proto; 108 } *hdr, _hdr; 109 110 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 111 if (!hdr) 112 return false; 113 /* 114 * Only look inside GRE if version zero and no 115 * routing 116 */ 117 if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) { 118 proto = hdr->proto; 119 nhoff += 4; 120 if (hdr->flags & GRE_CSUM) 121 nhoff += 4; 122 if (hdr->flags & GRE_KEY) 123 nhoff += 4; 124 if (hdr->flags & GRE_SEQ) 125 nhoff += 4; 126 if (proto == htons(ETH_P_TEB)) { 127 const struct ethhdr *eth; 128 struct ethhdr _eth; 129 130 eth = skb_header_pointer(skb, nhoff, 131 sizeof(_eth), &_eth); 132 if (!eth) 133 return false; 134 proto = eth->h_proto; 135 nhoff += sizeof(*eth); 136 } 137 goto again; 138 } 139 break; 140 } 141 case IPPROTO_IPIP: 142 goto again; 143 default: 144 break; 145 } 146 147 flow->ip_proto = ip_proto; 148 poff = proto_ports_offset(ip_proto); 149 if (poff >= 0) { 150 __be32 *ports, _ports; 151 152 nhoff += poff; 153 ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports); 154 if (ports) 155 flow->ports = *ports; 156 } 157 158 flow->thoff = (u16) nhoff; 159 160 return true; 161 } 162 EXPORT_SYMBOL(skb_flow_dissect); 163 164 static u32 hashrnd __read_mostly; 165 166 /* 167 * __skb_get_rxhash: calculate a flow hash based on src/dst addresses 168 * and src/dst port numbers. Sets rxhash in skb to non-zero hash value 169 * on success, zero indicates no valid hash. Also, sets l4_rxhash in skb 170 * if hash is a canonical 4-tuple hash over transport ports. 171 */ 172 void __skb_get_rxhash(struct sk_buff *skb) 173 { 174 struct flow_keys keys; 175 u32 hash; 176 177 if (!skb_flow_dissect(skb, &keys)) 178 return; 179 180 if (keys.ports) 181 skb->l4_rxhash = 1; 182 183 /* get a consistent hash (same value on both flow directions) */ 184 if (((__force u32)keys.dst < (__force u32)keys.src) || 185 (((__force u32)keys.dst == (__force u32)keys.src) && 186 ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { 187 swap(keys.dst, keys.src); 188 swap(keys.port16[0], keys.port16[1]); 189 } 190 191 hash = jhash_3words((__force u32)keys.dst, 192 (__force u32)keys.src, 193 (__force u32)keys.ports, hashrnd); 194 if (!hash) 195 hash = 1; 196 197 skb->rxhash = hash; 198 } 199 EXPORT_SYMBOL(__skb_get_rxhash); 200 201 /* 202 * Returns a Tx hash based on the given packet descriptor a Tx queues' number 203 * to be used as a distribution range. 204 */ 205 u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb, 206 unsigned int num_tx_queues) 207 { 208 u32 hash; 209 u16 qoffset = 0; 210 u16 qcount = num_tx_queues; 211 212 if (skb_rx_queue_recorded(skb)) { 213 hash = skb_get_rx_queue(skb); 214 while (unlikely(hash >= num_tx_queues)) 215 hash -= num_tx_queues; 216 return hash; 217 } 218 219 if (dev->num_tc) { 220 u8 tc = netdev_get_prio_tc_map(dev, skb->priority); 221 qoffset = dev->tc_to_txq[tc].offset; 222 qcount = dev->tc_to_txq[tc].count; 223 } 224 225 if (skb->sk && skb->sk->sk_hash) 226 hash = skb->sk->sk_hash; 227 else 228 hash = (__force u16) skb->protocol; 229 hash = jhash_1word(hash, hashrnd); 230 231 return (u16) (((u64) hash * qcount) >> 32) + qoffset; 232 } 233 EXPORT_SYMBOL(__skb_tx_hash); 234 235 /* __skb_get_poff() returns the offset to the payload as far as it could 236 * be dissected. The main user is currently BPF, so that we can dynamically 237 * truncate packets without needing to push actual payload to the user 238 * space and can analyze headers only, instead. 239 */ 240 u32 __skb_get_poff(const struct sk_buff *skb) 241 { 242 struct flow_keys keys; 243 u32 poff = 0; 244 245 if (!skb_flow_dissect(skb, &keys)) 246 return 0; 247 248 poff += keys.thoff; 249 switch (keys.ip_proto) { 250 case IPPROTO_TCP: { 251 const struct tcphdr *tcph; 252 struct tcphdr _tcph; 253 254 tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph); 255 if (!tcph) 256 return poff; 257 258 poff += max_t(u32, sizeof(struct tcphdr), tcph->doff * 4); 259 break; 260 } 261 case IPPROTO_UDP: 262 case IPPROTO_UDPLITE: 263 poff += sizeof(struct udphdr); 264 break; 265 /* For the rest, we do not really care about header 266 * extensions at this point for now. 267 */ 268 case IPPROTO_ICMP: 269 poff += sizeof(struct icmphdr); 270 break; 271 case IPPROTO_ICMPV6: 272 poff += sizeof(struct icmp6hdr); 273 break; 274 case IPPROTO_IGMP: 275 poff += sizeof(struct igmphdr); 276 break; 277 case IPPROTO_DCCP: 278 poff += sizeof(struct dccp_hdr); 279 break; 280 case IPPROTO_SCTP: 281 poff += sizeof(struct sctphdr); 282 break; 283 } 284 285 return poff; 286 } 287 288 static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index) 289 { 290 if (unlikely(queue_index >= dev->real_num_tx_queues)) { 291 net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n", 292 dev->name, queue_index, 293 dev->real_num_tx_queues); 294 return 0; 295 } 296 return queue_index; 297 } 298 299 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) 300 { 301 #ifdef CONFIG_XPS 302 struct xps_dev_maps *dev_maps; 303 struct xps_map *map; 304 int queue_index = -1; 305 306 rcu_read_lock(); 307 dev_maps = rcu_dereference(dev->xps_maps); 308 if (dev_maps) { 309 map = rcu_dereference( 310 dev_maps->cpu_map[raw_smp_processor_id()]); 311 if (map) { 312 if (map->len == 1) 313 queue_index = map->queues[0]; 314 else { 315 u32 hash; 316 if (skb->sk && skb->sk->sk_hash) 317 hash = skb->sk->sk_hash; 318 else 319 hash = (__force u16) skb->protocol ^ 320 skb->rxhash; 321 hash = jhash_1word(hash, hashrnd); 322 queue_index = map->queues[ 323 ((u64)hash * map->len) >> 32]; 324 } 325 if (unlikely(queue_index >= dev->real_num_tx_queues)) 326 queue_index = -1; 327 } 328 } 329 rcu_read_unlock(); 330 331 return queue_index; 332 #else 333 return -1; 334 #endif 335 } 336 337 u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb) 338 { 339 struct sock *sk = skb->sk; 340 int queue_index = sk_tx_queue_get(sk); 341 342 if (queue_index < 0 || skb->ooo_okay || 343 queue_index >= dev->real_num_tx_queues) { 344 int new_index = get_xps_queue(dev, skb); 345 if (new_index < 0) 346 new_index = skb_tx_hash(dev, skb); 347 348 if (queue_index != new_index && sk) { 349 struct dst_entry *dst = 350 rcu_dereference_check(sk->sk_dst_cache, 1); 351 352 if (dst && skb_dst(skb) == dst) 353 sk_tx_queue_set(sk, queue_index); 354 355 } 356 357 queue_index = new_index; 358 } 359 360 return queue_index; 361 } 362 EXPORT_SYMBOL(__netdev_pick_tx); 363 364 struct netdev_queue *netdev_pick_tx(struct net_device *dev, 365 struct sk_buff *skb) 366 { 367 int queue_index = 0; 368 369 if (dev->real_num_tx_queues != 1) { 370 const struct net_device_ops *ops = dev->netdev_ops; 371 if (ops->ndo_select_queue) 372 queue_index = ops->ndo_select_queue(dev, skb); 373 else 374 queue_index = __netdev_pick_tx(dev, skb); 375 queue_index = dev_cap_txqueue(dev, queue_index); 376 } 377 378 skb_set_queue_mapping(skb, queue_index); 379 return netdev_get_tx_queue(dev, queue_index); 380 } 381 382 static int __init initialize_hashrnd(void) 383 { 384 get_random_bytes(&hashrnd, sizeof(hashrnd)); 385 return 0; 386 } 387 388 late_initcall_sync(initialize_hashrnd); 389