aio: don't include aio.h in sched.h
[linux-3.10.git] / net / core / flow_dissector.c
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);