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 */
22static 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}
61EXPORT_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 */
74bool __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
88again:
89	switch (proto) {
90	case htons(ETH_P_IP): {
91		const struct iphdr *iph;
92		struct iphdr _iph;
93ip:
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
117ipv6:
118		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
119		if (!iph)
120			return false;
121
122		ip_proto = iph->nexthdr;
123		nhoff += sizeof(struct ipv6hdr);
124
125		/* see comment above in IPv4 section */
126		if (!skb)
127			break;
128
129		flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
130		flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
131
132		if (skb && ip6_flowlabel(iph)) {
133			__be32 flow_label = ip6_flowlabel(iph);
134
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_TIPC): {
182		struct {
183			__be32 pre[3];
184			__be32 srcnode;
185		} *hdr, _hdr;
186		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
187		if (!hdr)
188			return false;
189		flow->src = hdr->srcnode;
190		flow->dst = 0;
191		flow->n_proto = proto;
192		flow->thoff = (u16)nhoff;
193		return true;
194	}
195	case htons(ETH_P_FCOE):
196		flow->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
197		/* fall through */
198	default:
199		return false;
200	}
201
202	switch (ip_proto) {
203	case IPPROTO_GRE: {
204		struct gre_hdr {
205			__be16 flags;
206			__be16 proto;
207		} *hdr, _hdr;
208
209		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
210		if (!hdr)
211			return false;
212		/*
213		 * Only look inside GRE if version zero and no
214		 * routing
215		 */
216		if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
217			proto = hdr->proto;
218			nhoff += 4;
219			if (hdr->flags & GRE_CSUM)
220				nhoff += 4;
221			if (hdr->flags & GRE_KEY)
222				nhoff += 4;
223			if (hdr->flags & GRE_SEQ)
224				nhoff += 4;
225			if (proto == htons(ETH_P_TEB)) {
226				const struct ethhdr *eth;
227				struct ethhdr _eth;
228
229				eth = __skb_header_pointer(skb, nhoff,
230							   sizeof(_eth),
231							   data, hlen, &_eth);
232				if (!eth)
233					return false;
234				proto = eth->h_proto;
235				nhoff += sizeof(*eth);
236
237				/* Cap headers that we access via pointers at the
238				 * end of the Ethernet header as our maximum alignment
239				 * at that point is only 2 bytes.
240				 */
241				if (NET_IP_ALIGN)
242					hlen = nhoff;
243			}
244			goto again;
245		}
246		break;
247	}
248	case IPPROTO_IPIP:
249		proto = htons(ETH_P_IP);
250		goto ip;
251	case IPPROTO_IPV6:
252		proto = htons(ETH_P_IPV6);
253		goto ipv6;
254	default:
255		break;
256	}
257
258	flow->n_proto = proto;
259	flow->ip_proto = ip_proto;
260	flow->thoff = (u16) nhoff;
261
262	/* unless skb is set we don't need to record port info */
263	if (skb)
264		flow->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
265						   data, hlen);
266
267	return true;
268}
269EXPORT_SYMBOL(__skb_flow_dissect);
270
271static u32 hashrnd __read_mostly;
272static __always_inline void __flow_hash_secret_init(void)
273{
274	net_get_random_once(&hashrnd, sizeof(hashrnd));
275}
276
277static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c)
278{
279	__flow_hash_secret_init();
280	return jhash_3words(a, b, c, hashrnd);
281}
282
283static inline u32 __flow_hash_from_keys(struct flow_keys *keys)
284{
285	u32 hash;
286
287	/* get a consistent hash (same value on both flow directions) */
288	if (((__force u32)keys->dst < (__force u32)keys->src) ||
289	    (((__force u32)keys->dst == (__force u32)keys->src) &&
290	     ((__force u16)keys->port16[1] < (__force u16)keys->port16[0]))) {
291		swap(keys->dst, keys->src);
292		swap(keys->port16[0], keys->port16[1]);
293	}
294
295	hash = __flow_hash_3words((__force u32)keys->dst,
296				  (__force u32)keys->src,
297				  (__force u32)keys->ports);
298	if (!hash)
299		hash = 1;
300
301	return hash;
302}
303
304u32 flow_hash_from_keys(struct flow_keys *keys)
305{
306	return __flow_hash_from_keys(keys);
307}
308EXPORT_SYMBOL(flow_hash_from_keys);
309
310/*
311 * __skb_get_hash: calculate a flow hash based on src/dst addresses
312 * and src/dst port numbers.  Sets hash in skb to non-zero hash value
313 * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
314 * if hash is a canonical 4-tuple hash over transport ports.
315 */
316void __skb_get_hash(struct sk_buff *skb)
317{
318	struct flow_keys keys;
319
320	if (!skb_flow_dissect(skb, &keys))
321		return;
322
323	if (keys.ports)
324		skb->l4_hash = 1;
325
326	skb->sw_hash = 1;
327
328	skb->hash = __flow_hash_from_keys(&keys);
329}
330EXPORT_SYMBOL(__skb_get_hash);
331
332/*
333 * Returns a Tx hash based on the given packet descriptor a Tx queues' number
334 * to be used as a distribution range.
335 */
336u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
337		  unsigned int num_tx_queues)
338{
339	u32 hash;
340	u16 qoffset = 0;
341	u16 qcount = num_tx_queues;
342
343	if (skb_rx_queue_recorded(skb)) {
344		hash = skb_get_rx_queue(skb);
345		while (unlikely(hash >= num_tx_queues))
346			hash -= num_tx_queues;
347		return hash;
348	}
349
350	if (dev->num_tc) {
351		u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
352		qoffset = dev->tc_to_txq[tc].offset;
353		qcount = dev->tc_to_txq[tc].count;
354	}
355
356	return (u16) reciprocal_scale(skb_get_hash(skb), qcount) + qoffset;
357}
358EXPORT_SYMBOL(__skb_tx_hash);
359
360u32 __skb_get_poff(const struct sk_buff *skb, void *data,
361		   const struct flow_keys *keys, int hlen)
362{
363	u32 poff = keys->thoff;
364
365	switch (keys->ip_proto) {
366	case IPPROTO_TCP: {
367		/* access doff as u8 to avoid unaligned access */
368		const u8 *doff;
369		u8 _doff;
370
371		doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
372					    data, hlen, &_doff);
373		if (!doff)
374			return poff;
375
376		poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
377		break;
378	}
379	case IPPROTO_UDP:
380	case IPPROTO_UDPLITE:
381		poff += sizeof(struct udphdr);
382		break;
383	/* For the rest, we do not really care about header
384	 * extensions at this point for now.
385	 */
386	case IPPROTO_ICMP:
387		poff += sizeof(struct icmphdr);
388		break;
389	case IPPROTO_ICMPV6:
390		poff += sizeof(struct icmp6hdr);
391		break;
392	case IPPROTO_IGMP:
393		poff += sizeof(struct igmphdr);
394		break;
395	case IPPROTO_DCCP:
396		poff += sizeof(struct dccp_hdr);
397		break;
398	case IPPROTO_SCTP:
399		poff += sizeof(struct sctphdr);
400		break;
401	}
402
403	return poff;
404}
405
406/* skb_get_poff() returns the offset to the payload as far as it could
407 * be dissected. The main user is currently BPF, so that we can dynamically
408 * truncate packets without needing to push actual payload to the user
409 * space and can analyze headers only, instead.
410 */
411u32 skb_get_poff(const struct sk_buff *skb)
412{
413	struct flow_keys keys;
414
415	if (!skb_flow_dissect(skb, &keys))
416		return 0;
417
418	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
419}
420
421static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
422{
423#ifdef CONFIG_XPS
424	struct xps_dev_maps *dev_maps;
425	struct xps_map *map;
426	int queue_index = -1;
427
428	rcu_read_lock();
429	dev_maps = rcu_dereference(dev->xps_maps);
430	if (dev_maps) {
431		map = rcu_dereference(
432		    dev_maps->cpu_map[skb->sender_cpu - 1]);
433		if (map) {
434			if (map->len == 1)
435				queue_index = map->queues[0];
436			else
437				queue_index = map->queues[reciprocal_scale(skb_get_hash(skb),
438									   map->len)];
439			if (unlikely(queue_index >= dev->real_num_tx_queues))
440				queue_index = -1;
441		}
442	}
443	rcu_read_unlock();
444
445	return queue_index;
446#else
447	return -1;
448#endif
449}
450
451static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
452{
453	struct sock *sk = skb->sk;
454	int queue_index = sk_tx_queue_get(sk);
455
456	if (queue_index < 0 || skb->ooo_okay ||
457	    queue_index >= dev->real_num_tx_queues) {
458		int new_index = get_xps_queue(dev, skb);
459		if (new_index < 0)
460			new_index = skb_tx_hash(dev, skb);
461
462		if (queue_index != new_index && sk &&
463		    rcu_access_pointer(sk->sk_dst_cache))
464			sk_tx_queue_set(sk, new_index);
465
466		queue_index = new_index;
467	}
468
469	return queue_index;
470}
471
472struct netdev_queue *netdev_pick_tx(struct net_device *dev,
473				    struct sk_buff *skb,
474				    void *accel_priv)
475{
476	int queue_index = 0;
477
478#ifdef CONFIG_XPS
479	if (skb->sender_cpu == 0)
480		skb->sender_cpu = raw_smp_processor_id() + 1;
481#endif
482
483	if (dev->real_num_tx_queues != 1) {
484		const struct net_device_ops *ops = dev->netdev_ops;
485		if (ops->ndo_select_queue)
486			queue_index = ops->ndo_select_queue(dev, skb, accel_priv,
487							    __netdev_pick_tx);
488		else
489			queue_index = __netdev_pick_tx(dev, skb);
490
491		if (!accel_priv)
492			queue_index = netdev_cap_txqueue(dev, queue_index);
493	}
494
495	skb_set_queue_mapping(skb, queue_index);
496	return netdev_get_tx_queue(dev, queue_index);
497}
498