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_8021AD): 69 case __constant_htons(ETH_P_8021Q): { 70 const struct vlan_hdr *vlan; 71 struct vlan_hdr _vlan; 72 73 vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan); 74 if (!vlan) 75 return false; 76 77 proto = vlan->h_vlan_encapsulated_proto; 78 nhoff += sizeof(*vlan); 79 goto again; 80 } 81 case __constant_htons(ETH_P_PPP_SES): { 82 struct { 83 struct pppoe_hdr hdr; 84 __be16 proto; 85 } *hdr, _hdr; 86 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 87 if (!hdr) 88 return false; 89 proto = hdr->proto; 90 nhoff += PPPOE_SES_HLEN; 91 switch (proto) { 92 case __constant_htons(PPP_IP): 93 goto ip; 94 case __constant_htons(PPP_IPV6): 95 goto ipv6; 96 default: 97 return false; 98 } 99 } 100 default: 101 return false; 102 } 103 104 switch (ip_proto) { 105 case IPPROTO_GRE: { 106 struct gre_hdr { 107 __be16 flags; 108 __be16 proto; 109 } *hdr, _hdr; 110 111 hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); 112 if (!hdr) 113 return false; 114 /* 115 * Only look inside GRE if version zero and no 116 * routing 117 */ 118 if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) { 119 proto = hdr->proto; 120 nhoff += 4; 121 if (hdr->flags & GRE_CSUM) 122 nhoff += 4; 123 if (hdr->flags & GRE_KEY) 124 nhoff += 4; 125 if (hdr->flags & GRE_SEQ) 126 nhoff += 4; 127 if (proto == htons(ETH_P_TEB)) { 128 const struct ethhdr *eth; 129 struct ethhdr _eth; 130 131 eth = skb_header_pointer(skb, nhoff, 132 sizeof(_eth), &_eth); 133 if (!eth) 134 return false; 135 proto = eth->h_proto; 136 nhoff += sizeof(*eth); 137 } 138 goto again; 139 } 140 break; 141 } 142 case IPPROTO_IPIP: 143 goto again; 144 default: 145 break; 146 } 147 148 flow->ip_proto = ip_proto; 149 poff = proto_ports_offset(ip_proto); 150 if (poff >= 0) { 151 __be32 *ports, _ports; 152 153 nhoff += poff; 154 ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports); 155 if (ports) 156 flow->ports = *ports; 157 } 158 159 flow->thoff = (u16) nhoff; 160 161 return true; 162 } 163 EXPORT_SYMBOL(skb_flow_dissect); 164 165 static u32 hashrnd __read_mostly; 166 167 /* 168 * __skb_get_rxhash: calculate a flow hash based on src/dst addresses 169 * and src/dst port numbers. Sets rxhash in skb to non-zero hash value 170 * on success, zero indicates no valid hash. Also, sets l4_rxhash in skb 171 * if hash is a canonical 4-tuple hash over transport ports. 172 */ 173 void __skb_get_rxhash(struct sk_buff *skb) 174 { 175 struct flow_keys keys; 176 u32 hash; 177 178 if (!skb_flow_dissect(skb, &keys)) 179 return; 180 181 if (keys.ports) 182 skb->l4_rxhash = 1; 183 184 /* get a consistent hash (same value on both flow directions) */ 185 if (((__force u32)keys.dst < (__force u32)keys.src) || 186 (((__force u32)keys.dst == (__force u32)keys.src) && 187 ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { 188 swap(keys.dst, keys.src); 189 swap(keys.port16[0], keys.port16[1]); 190 } 191 192 hash = jhash_3words((__force u32)keys.dst, 193 (__force u32)keys.src, 194 (__force u32)keys.ports, hashrnd); 195 if (!hash) 196 hash = 1; 197 198 skb->rxhash = hash; 199 } 200 EXPORT_SYMBOL(__skb_get_rxhash); 201 202 /* 203 * Returns a Tx hash based on the given packet descriptor a Tx queues' number 204 * to be used as a distribution range. 205 */ 206 u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb, 207 unsigned int num_tx_queues) 208 { 209 u32 hash; 210 u16 qoffset = 0; 211 u16 qcount = num_tx_queues; 212 213 if (skb_rx_queue_recorded(skb)) { 214 hash = skb_get_rx_queue(skb); 215 while (unlikely(hash >= num_tx_queues)) 216 hash -= num_tx_queues; 217 return hash; 218 } 219 220 if (dev->num_tc) { 221 u8 tc = netdev_get_prio_tc_map(dev, skb->priority); 222 qoffset = dev->tc_to_txq[tc].offset; 223 qcount = dev->tc_to_txq[tc].count; 224 } 225 226 if (skb->sk && skb->sk->sk_hash) 227 hash = skb->sk->sk_hash; 228 else 229 hash = (__force u16) skb->protocol; 230 hash = jhash_1word(hash, hashrnd); 231 232 return (u16) (((u64) hash * qcount) >> 32) + qoffset; 233 } 234 EXPORT_SYMBOL(__skb_tx_hash); 235 236 /* __skb_get_poff() returns the offset to the payload as far as it could 237 * be dissected. The main user is currently BPF, so that we can dynamically 238 * truncate packets without needing to push actual payload to the user 239 * space and can analyze headers only, instead. 240 */ 241 u32 __skb_get_poff(const struct sk_buff *skb) 242 { 243 struct flow_keys keys; 244 u32 poff = 0; 245 246 if (!skb_flow_dissect(skb, &keys)) 247 return 0; 248 249 poff += keys.thoff; 250 switch (keys.ip_proto) { 251 case IPPROTO_TCP: { 252 const struct tcphdr *tcph; 253 struct tcphdr _tcph; 254 255 tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph); 256 if (!tcph) 257 return poff; 258 259 poff += max_t(u32, sizeof(struct tcphdr), tcph->doff * 4); 260 break; 261 } 262 case IPPROTO_UDP: 263 case IPPROTO_UDPLITE: 264 poff += sizeof(struct udphdr); 265 break; 266 /* For the rest, we do not really care about header 267 * extensions at this point for now. 268 */ 269 case IPPROTO_ICMP: 270 poff += sizeof(struct icmphdr); 271 break; 272 case IPPROTO_ICMPV6: 273 poff += sizeof(struct icmp6hdr); 274 break; 275 case IPPROTO_IGMP: 276 poff += sizeof(struct igmphdr); 277 break; 278 case IPPROTO_DCCP: 279 poff += sizeof(struct dccp_hdr); 280 break; 281 case IPPROTO_SCTP: 282 poff += sizeof(struct sctphdr); 283 break; 284 } 285 286 return poff; 287 } 288 289 static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index) 290 { 291 if (unlikely(queue_index >= dev->real_num_tx_queues)) { 292 net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n", 293 dev->name, queue_index, 294 dev->real_num_tx_queues); 295 return 0; 296 } 297 return queue_index; 298 } 299 300 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) 301 { 302 #ifdef CONFIG_XPS 303 struct xps_dev_maps *dev_maps; 304 struct xps_map *map; 305 int queue_index = -1; 306 307 rcu_read_lock(); 308 dev_maps = rcu_dereference(dev->xps_maps); 309 if (dev_maps) { 310 map = rcu_dereference( 311 dev_maps->cpu_map[raw_smp_processor_id()]); 312 if (map) { 313 if (map->len == 1) 314 queue_index = map->queues[0]; 315 else { 316 u32 hash; 317 if (skb->sk && skb->sk->sk_hash) 318 hash = skb->sk->sk_hash; 319 else 320 hash = (__force u16) skb->protocol ^ 321 skb->rxhash; 322 hash = jhash_1word(hash, hashrnd); 323 queue_index = map->queues[ 324 ((u64)hash * map->len) >> 32]; 325 } 326 if (unlikely(queue_index >= dev->real_num_tx_queues)) 327 queue_index = -1; 328 } 329 } 330 rcu_read_unlock(); 331 332 return queue_index; 333 #else 334 return -1; 335 #endif 336 } 337 338 u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb) 339 { 340 struct sock *sk = skb->sk; 341 int queue_index = sk_tx_queue_get(sk); 342 343 if (queue_index < 0 || skb->ooo_okay || 344 queue_index >= dev->real_num_tx_queues) { 345 int new_index = get_xps_queue(dev, skb); 346 if (new_index < 0) 347 new_index = skb_tx_hash(dev, skb); 348 349 if (queue_index != new_index && sk) { 350 struct dst_entry *dst = 351 rcu_dereference_check(sk->sk_dst_cache, 1); 352 353 if (dst && skb_dst(skb) == dst) 354 sk_tx_queue_set(sk, queue_index); 355 356 } 357 358 queue_index = new_index; 359 } 360 361 return queue_index; 362 } 363 EXPORT_SYMBOL(__netdev_pick_tx); 364 365 struct netdev_queue *netdev_pick_tx(struct net_device *dev, 366 struct sk_buff *skb) 367 { 368 int queue_index = 0; 369 370 if (dev->real_num_tx_queues != 1) { 371 const struct net_device_ops *ops = dev->netdev_ops; 372 if (ops->ndo_select_queue) 373 queue_index = ops->ndo_select_queue(dev, skb); 374 else 375 queue_index = __netdev_pick_tx(dev, skb); 376 queue_index = dev_cap_txqueue(dev, queue_index); 377 } 378 379 skb_set_queue_mapping(skb, queue_index); 380 return netdev_get_tx_queue(dev, queue_index); 381 } 382 383 static int __init initialize_hashrnd(void) 384 { 385 get_random_bytes(&hashrnd, sizeof(hashrnd)); 386 return 0; 387 } 388 389 late_initcall_sync(initialize_hashrnd); 390