1  // SPDX-License-Identifier: GPL-2.0-only
2  #include <linux/kernel.h>
3  #include <linux/skbuff.h>
4  #include <linux/export.h>
5  #include <linux/ip.h>
6  #include <linux/ipv6.h>
7  #include <linux/if_vlan.h>
8  #include <linux/filter.h>
9  #include <net/dsa.h>
10  #include <net/dst_metadata.h>
11  #include <net/ip.h>
12  #include <net/ipv6.h>
13  #include <net/gre.h>
14  #include <net/pptp.h>
15  #include <net/tipc.h>
16  #include <linux/igmp.h>
17  #include <linux/icmp.h>
18  #include <linux/sctp.h>
19  #include <linux/dccp.h>
20  #include <linux/if_tunnel.h>
21  #include <linux/if_pppox.h>
22  #include <linux/ppp_defs.h>
23  #include <linux/stddef.h>
24  #include <linux/if_ether.h>
25  #include <linux/if_hsr.h>
26  #include <linux/mpls.h>
27  #include <linux/tcp.h>
28  #include <linux/ptp_classify.h>
29  #include <net/flow_dissector.h>
30  #include <net/pkt_cls.h>
31  #include <scsi/fc/fc_fcoe.h>
32  #include <uapi/linux/batadv_packet.h>
33  #include <linux/bpf.h>
34  #if IS_ENABLED(CONFIG_NF_CONNTRACK)
35  #include <net/netfilter/nf_conntrack_core.h>
36  #include <net/netfilter/nf_conntrack_labels.h>
37  #endif
38  #include <linux/bpf-netns.h>
39  
dissector_set_key(struct flow_dissector * flow_dissector,enum flow_dissector_key_id key_id)40  static void dissector_set_key(struct flow_dissector *flow_dissector,
41  			      enum flow_dissector_key_id key_id)
42  {
43  	flow_dissector->used_keys |= (1ULL << key_id);
44  }
45  
skb_flow_dissector_init(struct flow_dissector * flow_dissector,const struct flow_dissector_key * key,unsigned int key_count)46  void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
47  			     const struct flow_dissector_key *key,
48  			     unsigned int key_count)
49  {
50  	unsigned int i;
51  
52  	memset(flow_dissector, 0, sizeof(*flow_dissector));
53  
54  	for (i = 0; i < key_count; i++, key++) {
55  		/* User should make sure that every key target offset is within
56  		 * boundaries of unsigned short.
57  		 */
58  		BUG_ON(key->offset > USHRT_MAX);
59  		BUG_ON(dissector_uses_key(flow_dissector,
60  					  key->key_id));
61  
62  		dissector_set_key(flow_dissector, key->key_id);
63  		flow_dissector->offset[key->key_id] = key->offset;
64  	}
65  
66  	/* Ensure that the dissector always includes control and basic key.
67  	 * That way we are able to avoid handling lack of these in fast path.
68  	 */
69  	BUG_ON(!dissector_uses_key(flow_dissector,
70  				   FLOW_DISSECTOR_KEY_CONTROL));
71  	BUG_ON(!dissector_uses_key(flow_dissector,
72  				   FLOW_DISSECTOR_KEY_BASIC));
73  }
74  EXPORT_SYMBOL(skb_flow_dissector_init);
75  
76  #ifdef CONFIG_BPF_SYSCALL
flow_dissector_bpf_prog_attach_check(struct net * net,struct bpf_prog * prog)77  int flow_dissector_bpf_prog_attach_check(struct net *net,
78  					 struct bpf_prog *prog)
79  {
80  	enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR;
81  
82  	if (net == &init_net) {
83  		/* BPF flow dissector in the root namespace overrides
84  		 * any per-net-namespace one. When attaching to root,
85  		 * make sure we don't have any BPF program attached
86  		 * to the non-root namespaces.
87  		 */
88  		struct net *ns;
89  
90  		for_each_net(ns) {
91  			if (ns == &init_net)
92  				continue;
93  			if (rcu_access_pointer(ns->bpf.run_array[type]))
94  				return -EEXIST;
95  		}
96  	} else {
97  		/* Make sure root flow dissector is not attached
98  		 * when attaching to the non-root namespace.
99  		 */
100  		if (rcu_access_pointer(init_net.bpf.run_array[type]))
101  			return -EEXIST;
102  	}
103  
104  	return 0;
105  }
106  #endif /* CONFIG_BPF_SYSCALL */
107  
108  /**
109   * __skb_flow_get_ports - extract the upper layer ports and return them
110   * @skb: sk_buff to extract the ports from
111   * @thoff: transport header offset
112   * @ip_proto: protocol for which to get port offset
113   * @data: raw buffer pointer to the packet, if NULL use skb->data
114   * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
115   *
116   * The function will try to retrieve the ports at offset thoff + poff where poff
117   * is the protocol port offset returned from proto_ports_offset
118   */
__skb_flow_get_ports(const struct sk_buff * skb,int thoff,u8 ip_proto,const void * data,int hlen)119  __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
120  			    const void *data, int hlen)
121  {
122  	int poff = proto_ports_offset(ip_proto);
123  
124  	if (!data) {
125  		data = skb->data;
126  		hlen = skb_headlen(skb);
127  	}
128  
129  	if (poff >= 0) {
130  		__be32 *ports, _ports;
131  
132  		ports = __skb_header_pointer(skb, thoff + poff,
133  					     sizeof(_ports), data, hlen, &_ports);
134  		if (ports)
135  			return *ports;
136  	}
137  
138  	return 0;
139  }
140  EXPORT_SYMBOL(__skb_flow_get_ports);
141  
icmp_has_id(u8 type)142  static bool icmp_has_id(u8 type)
143  {
144  	switch (type) {
145  	case ICMP_ECHO:
146  	case ICMP_ECHOREPLY:
147  	case ICMP_TIMESTAMP:
148  	case ICMP_TIMESTAMPREPLY:
149  	case ICMPV6_ECHO_REQUEST:
150  	case ICMPV6_ECHO_REPLY:
151  		return true;
152  	}
153  
154  	return false;
155  }
156  
157  /**
158   * skb_flow_get_icmp_tci - extract ICMP(6) Type, Code and Identifier fields
159   * @skb: sk_buff to extract from
160   * @key_icmp: struct flow_dissector_key_icmp to fill
161   * @data: raw buffer pointer to the packet
162   * @thoff: offset to extract at
163   * @hlen: packet header length
164   */
skb_flow_get_icmp_tci(const struct sk_buff * skb,struct flow_dissector_key_icmp * key_icmp,const void * data,int thoff,int hlen)165  void skb_flow_get_icmp_tci(const struct sk_buff *skb,
166  			   struct flow_dissector_key_icmp *key_icmp,
167  			   const void *data, int thoff, int hlen)
168  {
169  	struct icmphdr *ih, _ih;
170  
171  	ih = __skb_header_pointer(skb, thoff, sizeof(_ih), data, hlen, &_ih);
172  	if (!ih)
173  		return;
174  
175  	key_icmp->type = ih->type;
176  	key_icmp->code = ih->code;
177  
178  	/* As we use 0 to signal that the Id field is not present,
179  	 * avoid confusion with packets without such field
180  	 */
181  	if (icmp_has_id(ih->type))
182  		key_icmp->id = ih->un.echo.id ? ntohs(ih->un.echo.id) : 1;
183  	else
184  		key_icmp->id = 0;
185  }
186  EXPORT_SYMBOL(skb_flow_get_icmp_tci);
187  
188  /* If FLOW_DISSECTOR_KEY_ICMP is set, dissect an ICMP packet
189   * using skb_flow_get_icmp_tci().
190   */
__skb_flow_dissect_icmp(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int thoff,int hlen)191  static void __skb_flow_dissect_icmp(const struct sk_buff *skb,
192  				    struct flow_dissector *flow_dissector,
193  				    void *target_container, const void *data,
194  				    int thoff, int hlen)
195  {
196  	struct flow_dissector_key_icmp *key_icmp;
197  
198  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ICMP))
199  		return;
200  
201  	key_icmp = skb_flow_dissector_target(flow_dissector,
202  					     FLOW_DISSECTOR_KEY_ICMP,
203  					     target_container);
204  
205  	skb_flow_get_icmp_tci(skb, key_icmp, data, thoff, hlen);
206  }
207  
__skb_flow_dissect_ah(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen)208  static void __skb_flow_dissect_ah(const struct sk_buff *skb,
209  				  struct flow_dissector *flow_dissector,
210  				  void *target_container, const void *data,
211  				  int nhoff, int hlen)
212  {
213  	struct flow_dissector_key_ipsec *key_ah;
214  	struct ip_auth_hdr _hdr, *hdr;
215  
216  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPSEC))
217  		return;
218  
219  	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
220  	if (!hdr)
221  		return;
222  
223  	key_ah = skb_flow_dissector_target(flow_dissector,
224  					   FLOW_DISSECTOR_KEY_IPSEC,
225  					   target_container);
226  
227  	key_ah->spi = hdr->spi;
228  }
229  
__skb_flow_dissect_esp(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen)230  static void __skb_flow_dissect_esp(const struct sk_buff *skb,
231  				   struct flow_dissector *flow_dissector,
232  				   void *target_container, const void *data,
233  				   int nhoff, int hlen)
234  {
235  	struct flow_dissector_key_ipsec *key_esp;
236  	struct ip_esp_hdr _hdr, *hdr;
237  
238  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPSEC))
239  		return;
240  
241  	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
242  	if (!hdr)
243  		return;
244  
245  	key_esp = skb_flow_dissector_target(flow_dissector,
246  					    FLOW_DISSECTOR_KEY_IPSEC,
247  					    target_container);
248  
249  	key_esp->spi = hdr->spi;
250  }
251  
__skb_flow_dissect_l2tpv3(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen)252  static void __skb_flow_dissect_l2tpv3(const struct sk_buff *skb,
253  				      struct flow_dissector *flow_dissector,
254  				      void *target_container, const void *data,
255  				      int nhoff, int hlen)
256  {
257  	struct flow_dissector_key_l2tpv3 *key_l2tpv3;
258  	struct {
259  		__be32 session_id;
260  	} *hdr, _hdr;
261  
262  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_L2TPV3))
263  		return;
264  
265  	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
266  	if (!hdr)
267  		return;
268  
269  	key_l2tpv3 = skb_flow_dissector_target(flow_dissector,
270  					       FLOW_DISSECTOR_KEY_L2TPV3,
271  					       target_container);
272  
273  	key_l2tpv3->session_id = hdr->session_id;
274  }
275  
skb_flow_dissect_meta(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container)276  void skb_flow_dissect_meta(const struct sk_buff *skb,
277  			   struct flow_dissector *flow_dissector,
278  			   void *target_container)
279  {
280  	struct flow_dissector_key_meta *meta;
281  
282  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_META))
283  		return;
284  
285  	meta = skb_flow_dissector_target(flow_dissector,
286  					 FLOW_DISSECTOR_KEY_META,
287  					 target_container);
288  	meta->ingress_ifindex = skb->skb_iif;
289  #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
290  	if (tc_skb_ext_tc_enabled()) {
291  		struct tc_skb_ext *ext;
292  
293  		ext = skb_ext_find(skb, TC_SKB_EXT);
294  		if (ext)
295  			meta->l2_miss = ext->l2_miss;
296  	}
297  #endif
298  }
299  EXPORT_SYMBOL(skb_flow_dissect_meta);
300  
301  static void
skb_flow_dissect_set_enc_control(enum flow_dissector_key_id type,u32 ctrl_flags,struct flow_dissector * flow_dissector,void * target_container)302  skb_flow_dissect_set_enc_control(enum flow_dissector_key_id type,
303  				 u32 ctrl_flags,
304  				 struct flow_dissector *flow_dissector,
305  				 void *target_container)
306  {
307  	struct flow_dissector_key_control *ctrl;
308  
309  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL))
310  		return;
311  
312  	ctrl = skb_flow_dissector_target(flow_dissector,
313  					 FLOW_DISSECTOR_KEY_ENC_CONTROL,
314  					 target_container);
315  	ctrl->addr_type = type;
316  	ctrl->flags = ctrl_flags;
317  }
318  
319  void
skb_flow_dissect_ct(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,u16 * ctinfo_map,size_t mapsize,bool post_ct,u16 zone)320  skb_flow_dissect_ct(const struct sk_buff *skb,
321  		    struct flow_dissector *flow_dissector,
322  		    void *target_container, u16 *ctinfo_map,
323  		    size_t mapsize, bool post_ct, u16 zone)
324  {
325  #if IS_ENABLED(CONFIG_NF_CONNTRACK)
326  	struct flow_dissector_key_ct *key;
327  	enum ip_conntrack_info ctinfo;
328  	struct nf_conn_labels *cl;
329  	struct nf_conn *ct;
330  
331  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_CT))
332  		return;
333  
334  	ct = nf_ct_get(skb, &ctinfo);
335  	if (!ct && !post_ct)
336  		return;
337  
338  	key = skb_flow_dissector_target(flow_dissector,
339  					FLOW_DISSECTOR_KEY_CT,
340  					target_container);
341  
342  	if (!ct) {
343  		key->ct_state = TCA_FLOWER_KEY_CT_FLAGS_TRACKED |
344  				TCA_FLOWER_KEY_CT_FLAGS_INVALID;
345  		key->ct_zone = zone;
346  		return;
347  	}
348  
349  	if (ctinfo < mapsize)
350  		key->ct_state = ctinfo_map[ctinfo];
351  #if IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES)
352  	key->ct_zone = ct->zone.id;
353  #endif
354  #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
355  	key->ct_mark = READ_ONCE(ct->mark);
356  #endif
357  
358  	cl = nf_ct_labels_find(ct);
359  	if (cl)
360  		memcpy(key->ct_labels, cl->bits, sizeof(key->ct_labels));
361  #endif /* CONFIG_NF_CONNTRACK */
362  }
363  EXPORT_SYMBOL(skb_flow_dissect_ct);
364  
365  void
skb_flow_dissect_tunnel_info(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container)366  skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
367  			     struct flow_dissector *flow_dissector,
368  			     void *target_container)
369  {
370  	struct ip_tunnel_info *info;
371  	struct ip_tunnel_key *key;
372  	u32 ctrl_flags = 0;
373  
374  	/* A quick check to see if there might be something to do. */
375  	if (!dissector_uses_key(flow_dissector,
376  				FLOW_DISSECTOR_KEY_ENC_KEYID) &&
377  	    !dissector_uses_key(flow_dissector,
378  				FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) &&
379  	    !dissector_uses_key(flow_dissector,
380  				FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) &&
381  	    !dissector_uses_key(flow_dissector,
382  				FLOW_DISSECTOR_KEY_ENC_CONTROL) &&
383  	    !dissector_uses_key(flow_dissector,
384  				FLOW_DISSECTOR_KEY_ENC_PORTS) &&
385  	    !dissector_uses_key(flow_dissector,
386  				FLOW_DISSECTOR_KEY_ENC_IP) &&
387  	    !dissector_uses_key(flow_dissector,
388  				FLOW_DISSECTOR_KEY_ENC_OPTS))
389  		return;
390  
391  	info = skb_tunnel_info(skb);
392  	if (!info)
393  		return;
394  
395  	key = &info->key;
396  
397  	if (test_bit(IP_TUNNEL_CSUM_BIT, key->tun_flags))
398  		ctrl_flags |= FLOW_DIS_F_TUNNEL_CSUM;
399  	if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, key->tun_flags))
400  		ctrl_flags |= FLOW_DIS_F_TUNNEL_DONT_FRAGMENT;
401  	if (test_bit(IP_TUNNEL_OAM_BIT, key->tun_flags))
402  		ctrl_flags |= FLOW_DIS_F_TUNNEL_OAM;
403  	if (test_bit(IP_TUNNEL_CRIT_OPT_BIT, key->tun_flags))
404  		ctrl_flags |= FLOW_DIS_F_TUNNEL_CRIT_OPT;
405  
406  	switch (ip_tunnel_info_af(info)) {
407  	case AF_INET:
408  		skb_flow_dissect_set_enc_control(FLOW_DISSECTOR_KEY_IPV4_ADDRS,
409  						 ctrl_flags, flow_dissector,
410  						 target_container);
411  		if (dissector_uses_key(flow_dissector,
412  				       FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS)) {
413  			struct flow_dissector_key_ipv4_addrs *ipv4;
414  
415  			ipv4 = skb_flow_dissector_target(flow_dissector,
416  							 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS,
417  							 target_container);
418  			ipv4->src = key->u.ipv4.src;
419  			ipv4->dst = key->u.ipv4.dst;
420  		}
421  		break;
422  	case AF_INET6:
423  		skb_flow_dissect_set_enc_control(FLOW_DISSECTOR_KEY_IPV6_ADDRS,
424  						 ctrl_flags, flow_dissector,
425  						 target_container);
426  		if (dissector_uses_key(flow_dissector,
427  				       FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS)) {
428  			struct flow_dissector_key_ipv6_addrs *ipv6;
429  
430  			ipv6 = skb_flow_dissector_target(flow_dissector,
431  							 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS,
432  							 target_container);
433  			ipv6->src = key->u.ipv6.src;
434  			ipv6->dst = key->u.ipv6.dst;
435  		}
436  		break;
437  	default:
438  		skb_flow_dissect_set_enc_control(0, ctrl_flags, flow_dissector,
439  						 target_container);
440  		break;
441  	}
442  
443  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_KEYID)) {
444  		struct flow_dissector_key_keyid *keyid;
445  
446  		keyid = skb_flow_dissector_target(flow_dissector,
447  						  FLOW_DISSECTOR_KEY_ENC_KEYID,
448  						  target_container);
449  		keyid->keyid = tunnel_id_to_key32(key->tun_id);
450  	}
451  
452  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_PORTS)) {
453  		struct flow_dissector_key_ports *tp;
454  
455  		tp = skb_flow_dissector_target(flow_dissector,
456  					       FLOW_DISSECTOR_KEY_ENC_PORTS,
457  					       target_container);
458  		tp->src = key->tp_src;
459  		tp->dst = key->tp_dst;
460  	}
461  
462  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_IP)) {
463  		struct flow_dissector_key_ip *ip;
464  
465  		ip = skb_flow_dissector_target(flow_dissector,
466  					       FLOW_DISSECTOR_KEY_ENC_IP,
467  					       target_container);
468  		ip->tos = key->tos;
469  		ip->ttl = key->ttl;
470  	}
471  
472  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_OPTS)) {
473  		struct flow_dissector_key_enc_opts *enc_opt;
474  		IP_TUNNEL_DECLARE_FLAGS(flags) = { };
475  		u32 val;
476  
477  		enc_opt = skb_flow_dissector_target(flow_dissector,
478  						    FLOW_DISSECTOR_KEY_ENC_OPTS,
479  						    target_container);
480  
481  		if (!info->options_len)
482  			return;
483  
484  		enc_opt->len = info->options_len;
485  		ip_tunnel_info_opts_get(enc_opt->data, info);
486  
487  		ip_tunnel_set_options_present(flags);
488  		ip_tunnel_flags_and(flags, info->key.tun_flags, flags);
489  
490  		val = find_next_bit(flags, __IP_TUNNEL_FLAG_NUM,
491  				    IP_TUNNEL_GENEVE_OPT_BIT);
492  		enc_opt->dst_opt_type = val < __IP_TUNNEL_FLAG_NUM ? val : 0;
493  	}
494  }
495  EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
496  
skb_flow_dissect_hash(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container)497  void skb_flow_dissect_hash(const struct sk_buff *skb,
498  			   struct flow_dissector *flow_dissector,
499  			   void *target_container)
500  {
501  	struct flow_dissector_key_hash *key;
502  
503  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_HASH))
504  		return;
505  
506  	key = skb_flow_dissector_target(flow_dissector,
507  					FLOW_DISSECTOR_KEY_HASH,
508  					target_container);
509  
510  	key->hash = skb_get_hash_raw(skb);
511  }
512  EXPORT_SYMBOL(skb_flow_dissect_hash);
513  
514  static enum flow_dissect_ret
__skb_flow_dissect_mpls(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen,int lse_index,bool * entropy_label)515  __skb_flow_dissect_mpls(const struct sk_buff *skb,
516  			struct flow_dissector *flow_dissector,
517  			void *target_container, const void *data, int nhoff,
518  			int hlen, int lse_index, bool *entropy_label)
519  {
520  	struct mpls_label *hdr, _hdr;
521  	u32 entry, label, bos;
522  
523  	if (!dissector_uses_key(flow_dissector,
524  				FLOW_DISSECTOR_KEY_MPLS_ENTROPY) &&
525  	    !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS))
526  		return FLOW_DISSECT_RET_OUT_GOOD;
527  
528  	if (lse_index >= FLOW_DIS_MPLS_MAX)
529  		return FLOW_DISSECT_RET_OUT_GOOD;
530  
531  	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
532  				   hlen, &_hdr);
533  	if (!hdr)
534  		return FLOW_DISSECT_RET_OUT_BAD;
535  
536  	entry = ntohl(hdr->entry);
537  	label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
538  	bos = (entry & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT;
539  
540  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) {
541  		struct flow_dissector_key_mpls *key_mpls;
542  		struct flow_dissector_mpls_lse *lse;
543  
544  		key_mpls = skb_flow_dissector_target(flow_dissector,
545  						     FLOW_DISSECTOR_KEY_MPLS,
546  						     target_container);
547  		lse = &key_mpls->ls[lse_index];
548  
549  		lse->mpls_ttl = (entry & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
550  		lse->mpls_bos = bos;
551  		lse->mpls_tc = (entry & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT;
552  		lse->mpls_label = label;
553  		dissector_set_mpls_lse(key_mpls, lse_index);
554  	}
555  
556  	if (*entropy_label &&
557  	    dissector_uses_key(flow_dissector,
558  			       FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
559  		struct flow_dissector_key_keyid *key_keyid;
560  
561  		key_keyid = skb_flow_dissector_target(flow_dissector,
562  						      FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
563  						      target_container);
564  		key_keyid->keyid = cpu_to_be32(label);
565  	}
566  
567  	*entropy_label = label == MPLS_LABEL_ENTROPY;
568  
569  	return bos ? FLOW_DISSECT_RET_OUT_GOOD : FLOW_DISSECT_RET_PROTO_AGAIN;
570  }
571  
572  static enum flow_dissect_ret
__skb_flow_dissect_arp(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen)573  __skb_flow_dissect_arp(const struct sk_buff *skb,
574  		       struct flow_dissector *flow_dissector,
575  		       void *target_container, const void *data,
576  		       int nhoff, int hlen)
577  {
578  	struct flow_dissector_key_arp *key_arp;
579  	struct {
580  		unsigned char ar_sha[ETH_ALEN];
581  		unsigned char ar_sip[4];
582  		unsigned char ar_tha[ETH_ALEN];
583  		unsigned char ar_tip[4];
584  	} *arp_eth, _arp_eth;
585  	const struct arphdr *arp;
586  	struct arphdr _arp;
587  
588  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP))
589  		return FLOW_DISSECT_RET_OUT_GOOD;
590  
591  	arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,
592  				   hlen, &_arp);
593  	if (!arp)
594  		return FLOW_DISSECT_RET_OUT_BAD;
595  
596  	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
597  	    arp->ar_pro != htons(ETH_P_IP) ||
598  	    arp->ar_hln != ETH_ALEN ||
599  	    arp->ar_pln != 4 ||
600  	    (arp->ar_op != htons(ARPOP_REPLY) &&
601  	     arp->ar_op != htons(ARPOP_REQUEST)))
602  		return FLOW_DISSECT_RET_OUT_BAD;
603  
604  	arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),
605  				       sizeof(_arp_eth), data,
606  				       hlen, &_arp_eth);
607  	if (!arp_eth)
608  		return FLOW_DISSECT_RET_OUT_BAD;
609  
610  	key_arp = skb_flow_dissector_target(flow_dissector,
611  					    FLOW_DISSECTOR_KEY_ARP,
612  					    target_container);
613  
614  	memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip));
615  	memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip));
616  
617  	/* Only store the lower byte of the opcode;
618  	 * this covers ARPOP_REPLY and ARPOP_REQUEST.
619  	 */
620  	key_arp->op = ntohs(arp->ar_op) & 0xff;
621  
622  	ether_addr_copy(key_arp->sha, arp_eth->ar_sha);
623  	ether_addr_copy(key_arp->tha, arp_eth->ar_tha);
624  
625  	return FLOW_DISSECT_RET_OUT_GOOD;
626  }
627  
628  static enum flow_dissect_ret
__skb_flow_dissect_cfm(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,int hlen)629  __skb_flow_dissect_cfm(const struct sk_buff *skb,
630  		       struct flow_dissector *flow_dissector,
631  		       void *target_container, const void *data,
632  		       int nhoff, int hlen)
633  {
634  	struct flow_dissector_key_cfm *key, *hdr, _hdr;
635  
636  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_CFM))
637  		return FLOW_DISSECT_RET_OUT_GOOD;
638  
639  	hdr = __skb_header_pointer(skb, nhoff, sizeof(*key), data, hlen, &_hdr);
640  	if (!hdr)
641  		return FLOW_DISSECT_RET_OUT_BAD;
642  
643  	key = skb_flow_dissector_target(flow_dissector, FLOW_DISSECTOR_KEY_CFM,
644  					target_container);
645  
646  	key->mdl_ver = hdr->mdl_ver;
647  	key->opcode = hdr->opcode;
648  
649  	return FLOW_DISSECT_RET_OUT_GOOD;
650  }
651  
652  static enum flow_dissect_ret
__skb_flow_dissect_gre(const struct sk_buff * skb,struct flow_dissector_key_control * key_control,struct flow_dissector * flow_dissector,void * target_container,const void * data,__be16 * p_proto,int * p_nhoff,int * p_hlen,unsigned int flags)653  __skb_flow_dissect_gre(const struct sk_buff *skb,
654  		       struct flow_dissector_key_control *key_control,
655  		       struct flow_dissector *flow_dissector,
656  		       void *target_container, const void *data,
657  		       __be16 *p_proto, int *p_nhoff, int *p_hlen,
658  		       unsigned int flags)
659  {
660  	struct flow_dissector_key_keyid *key_keyid;
661  	struct gre_base_hdr *hdr, _hdr;
662  	int offset = 0;
663  	u16 gre_ver;
664  
665  	hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr),
666  				   data, *p_hlen, &_hdr);
667  	if (!hdr)
668  		return FLOW_DISSECT_RET_OUT_BAD;
669  
670  	/* Only look inside GRE without routing */
671  	if (hdr->flags & GRE_ROUTING)
672  		return FLOW_DISSECT_RET_OUT_GOOD;
673  
674  	/* Only look inside GRE for version 0 and 1 */
675  	gre_ver = ntohs(hdr->flags & GRE_VERSION);
676  	if (gre_ver > 1)
677  		return FLOW_DISSECT_RET_OUT_GOOD;
678  
679  	*p_proto = hdr->protocol;
680  	if (gre_ver) {
681  		/* Version1 must be PPTP, and check the flags */
682  		if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY)))
683  			return FLOW_DISSECT_RET_OUT_GOOD;
684  	}
685  
686  	offset += sizeof(struct gre_base_hdr);
687  
688  	if (hdr->flags & GRE_CSUM)
689  		offset += sizeof_field(struct gre_full_hdr, csum) +
690  			  sizeof_field(struct gre_full_hdr, reserved1);
691  
692  	if (hdr->flags & GRE_KEY) {
693  		const __be32 *keyid;
694  		__be32 _keyid;
695  
696  		keyid = __skb_header_pointer(skb, *p_nhoff + offset,
697  					     sizeof(_keyid),
698  					     data, *p_hlen, &_keyid);
699  		if (!keyid)
700  			return FLOW_DISSECT_RET_OUT_BAD;
701  
702  		if (dissector_uses_key(flow_dissector,
703  				       FLOW_DISSECTOR_KEY_GRE_KEYID)) {
704  			key_keyid = skb_flow_dissector_target(flow_dissector,
705  							      FLOW_DISSECTOR_KEY_GRE_KEYID,
706  							      target_container);
707  			if (gre_ver == 0)
708  				key_keyid->keyid = *keyid;
709  			else
710  				key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK;
711  		}
712  		offset += sizeof_field(struct gre_full_hdr, key);
713  	}
714  
715  	if (hdr->flags & GRE_SEQ)
716  		offset += sizeof_field(struct pptp_gre_header, seq);
717  
718  	if (gre_ver == 0) {
719  		if (*p_proto == htons(ETH_P_TEB)) {
720  			const struct ethhdr *eth;
721  			struct ethhdr _eth;
722  
723  			eth = __skb_header_pointer(skb, *p_nhoff + offset,
724  						   sizeof(_eth),
725  						   data, *p_hlen, &_eth);
726  			if (!eth)
727  				return FLOW_DISSECT_RET_OUT_BAD;
728  			*p_proto = eth->h_proto;
729  			offset += sizeof(*eth);
730  
731  			/* Cap headers that we access via pointers at the
732  			 * end of the Ethernet header as our maximum alignment
733  			 * at that point is only 2 bytes.
734  			 */
735  			if (NET_IP_ALIGN)
736  				*p_hlen = *p_nhoff + offset;
737  		}
738  	} else { /* version 1, must be PPTP */
739  		u8 _ppp_hdr[PPP_HDRLEN];
740  		u8 *ppp_hdr;
741  
742  		if (hdr->flags & GRE_ACK)
743  			offset += sizeof_field(struct pptp_gre_header, ack);
744  
745  		ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset,
746  					       sizeof(_ppp_hdr),
747  					       data, *p_hlen, _ppp_hdr);
748  		if (!ppp_hdr)
749  			return FLOW_DISSECT_RET_OUT_BAD;
750  
751  		switch (PPP_PROTOCOL(ppp_hdr)) {
752  		case PPP_IP:
753  			*p_proto = htons(ETH_P_IP);
754  			break;
755  		case PPP_IPV6:
756  			*p_proto = htons(ETH_P_IPV6);
757  			break;
758  		default:
759  			/* Could probably catch some more like MPLS */
760  			break;
761  		}
762  
763  		offset += PPP_HDRLEN;
764  	}
765  
766  	*p_nhoff += offset;
767  	key_control->flags |= FLOW_DIS_ENCAPSULATION;
768  	if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
769  		return FLOW_DISSECT_RET_OUT_GOOD;
770  
771  	return FLOW_DISSECT_RET_PROTO_AGAIN;
772  }
773  
774  /**
775   * __skb_flow_dissect_batadv() - dissect batman-adv header
776   * @skb: sk_buff to with the batman-adv header
777   * @key_control: flow dissectors control key
778   * @data: raw buffer pointer to the packet, if NULL use skb->data
779   * @p_proto: pointer used to update the protocol to process next
780   * @p_nhoff: pointer used to update inner network header offset
781   * @hlen: packet header length
782   * @flags: any combination of FLOW_DISSECTOR_F_*
783   *
784   * ETH_P_BATMAN packets are tried to be dissected. Only
785   * &struct batadv_unicast packets are actually processed because they contain an
786   * inner ethernet header and are usually followed by actual network header. This
787   * allows the flow dissector to continue processing the packet.
788   *
789   * Return: FLOW_DISSECT_RET_PROTO_AGAIN when &struct batadv_unicast was found,
790   *  FLOW_DISSECT_RET_OUT_GOOD when dissector should stop after encapsulation,
791   *  otherwise FLOW_DISSECT_RET_OUT_BAD
792   */
793  static enum flow_dissect_ret
__skb_flow_dissect_batadv(const struct sk_buff * skb,struct flow_dissector_key_control * key_control,const void * data,__be16 * p_proto,int * p_nhoff,int hlen,unsigned int flags)794  __skb_flow_dissect_batadv(const struct sk_buff *skb,
795  			  struct flow_dissector_key_control *key_control,
796  			  const void *data, __be16 *p_proto, int *p_nhoff,
797  			  int hlen, unsigned int flags)
798  {
799  	struct {
800  		struct batadv_unicast_packet batadv_unicast;
801  		struct ethhdr eth;
802  	} *hdr, _hdr;
803  
804  	hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), data, hlen,
805  				   &_hdr);
806  	if (!hdr)
807  		return FLOW_DISSECT_RET_OUT_BAD;
808  
809  	if (hdr->batadv_unicast.version != BATADV_COMPAT_VERSION)
810  		return FLOW_DISSECT_RET_OUT_BAD;
811  
812  	if (hdr->batadv_unicast.packet_type != BATADV_UNICAST)
813  		return FLOW_DISSECT_RET_OUT_BAD;
814  
815  	*p_proto = hdr->eth.h_proto;
816  	*p_nhoff += sizeof(*hdr);
817  
818  	key_control->flags |= FLOW_DIS_ENCAPSULATION;
819  	if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
820  		return FLOW_DISSECT_RET_OUT_GOOD;
821  
822  	return FLOW_DISSECT_RET_PROTO_AGAIN;
823  }
824  
825  static void
__skb_flow_dissect_tcp(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int thoff,int hlen)826  __skb_flow_dissect_tcp(const struct sk_buff *skb,
827  		       struct flow_dissector *flow_dissector,
828  		       void *target_container, const void *data,
829  		       int thoff, int hlen)
830  {
831  	struct flow_dissector_key_tcp *key_tcp;
832  	struct tcphdr *th, _th;
833  
834  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_TCP))
835  		return;
836  
837  	th = __skb_header_pointer(skb, thoff, sizeof(_th), data, hlen, &_th);
838  	if (!th)
839  		return;
840  
841  	if (unlikely(__tcp_hdrlen(th) < sizeof(_th)))
842  		return;
843  
844  	key_tcp = skb_flow_dissector_target(flow_dissector,
845  					    FLOW_DISSECTOR_KEY_TCP,
846  					    target_container);
847  	key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF));
848  }
849  
850  static void
__skb_flow_dissect_ports(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,int nhoff,u8 ip_proto,int hlen)851  __skb_flow_dissect_ports(const struct sk_buff *skb,
852  			 struct flow_dissector *flow_dissector,
853  			 void *target_container, const void *data,
854  			 int nhoff, u8 ip_proto, int hlen)
855  {
856  	enum flow_dissector_key_id dissector_ports = FLOW_DISSECTOR_KEY_MAX;
857  	struct flow_dissector_key_ports *key_ports;
858  
859  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS))
860  		dissector_ports = FLOW_DISSECTOR_KEY_PORTS;
861  	else if (dissector_uses_key(flow_dissector,
862  				    FLOW_DISSECTOR_KEY_PORTS_RANGE))
863  		dissector_ports = FLOW_DISSECTOR_KEY_PORTS_RANGE;
864  
865  	if (dissector_ports == FLOW_DISSECTOR_KEY_MAX)
866  		return;
867  
868  	key_ports = skb_flow_dissector_target(flow_dissector,
869  					      dissector_ports,
870  					      target_container);
871  	key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
872  						data, hlen);
873  }
874  
875  static void
__skb_flow_dissect_ipv4(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,const struct iphdr * iph)876  __skb_flow_dissect_ipv4(const struct sk_buff *skb,
877  			struct flow_dissector *flow_dissector,
878  			void *target_container, const void *data,
879  			const struct iphdr *iph)
880  {
881  	struct flow_dissector_key_ip *key_ip;
882  
883  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
884  		return;
885  
886  	key_ip = skb_flow_dissector_target(flow_dissector,
887  					   FLOW_DISSECTOR_KEY_IP,
888  					   target_container);
889  	key_ip->tos = iph->tos;
890  	key_ip->ttl = iph->ttl;
891  }
892  
893  static void
__skb_flow_dissect_ipv6(const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,const struct ipv6hdr * iph)894  __skb_flow_dissect_ipv6(const struct sk_buff *skb,
895  			struct flow_dissector *flow_dissector,
896  			void *target_container, const void *data,
897  			const struct ipv6hdr *iph)
898  {
899  	struct flow_dissector_key_ip *key_ip;
900  
901  	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
902  		return;
903  
904  	key_ip = skb_flow_dissector_target(flow_dissector,
905  					   FLOW_DISSECTOR_KEY_IP,
906  					   target_container);
907  	key_ip->tos = ipv6_get_dsfield(iph);
908  	key_ip->ttl = iph->hop_limit;
909  }
910  
911  /* Maximum number of protocol headers that can be parsed in
912   * __skb_flow_dissect
913   */
914  #define MAX_FLOW_DISSECT_HDRS	15
915  
skb_flow_dissect_allowed(int * num_hdrs)916  static bool skb_flow_dissect_allowed(int *num_hdrs)
917  {
918  	++*num_hdrs;
919  
920  	return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS);
921  }
922  
__skb_flow_bpf_to_target(const struct bpf_flow_keys * flow_keys,struct flow_dissector * flow_dissector,void * target_container)923  static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
924  				     struct flow_dissector *flow_dissector,
925  				     void *target_container)
926  {
927  	struct flow_dissector_key_ports *key_ports = NULL;
928  	struct flow_dissector_key_control *key_control;
929  	struct flow_dissector_key_basic *key_basic;
930  	struct flow_dissector_key_addrs *key_addrs;
931  	struct flow_dissector_key_tags *key_tags;
932  
933  	key_control = skb_flow_dissector_target(flow_dissector,
934  						FLOW_DISSECTOR_KEY_CONTROL,
935  						target_container);
936  	key_control->thoff = flow_keys->thoff;
937  	if (flow_keys->is_frag)
938  		key_control->flags |= FLOW_DIS_IS_FRAGMENT;
939  	if (flow_keys->is_first_frag)
940  		key_control->flags |= FLOW_DIS_FIRST_FRAG;
941  	if (flow_keys->is_encap)
942  		key_control->flags |= FLOW_DIS_ENCAPSULATION;
943  
944  	key_basic = skb_flow_dissector_target(flow_dissector,
945  					      FLOW_DISSECTOR_KEY_BASIC,
946  					      target_container);
947  	key_basic->n_proto = flow_keys->n_proto;
948  	key_basic->ip_proto = flow_keys->ip_proto;
949  
950  	if (flow_keys->addr_proto == ETH_P_IP &&
951  	    dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
952  		key_addrs = skb_flow_dissector_target(flow_dissector,
953  						      FLOW_DISSECTOR_KEY_IPV4_ADDRS,
954  						      target_container);
955  		key_addrs->v4addrs.src = flow_keys->ipv4_src;
956  		key_addrs->v4addrs.dst = flow_keys->ipv4_dst;
957  		key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
958  	} else if (flow_keys->addr_proto == ETH_P_IPV6 &&
959  		   dissector_uses_key(flow_dissector,
960  				      FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
961  		key_addrs = skb_flow_dissector_target(flow_dissector,
962  						      FLOW_DISSECTOR_KEY_IPV6_ADDRS,
963  						      target_container);
964  		memcpy(&key_addrs->v6addrs.src, &flow_keys->ipv6_src,
965  		       sizeof(key_addrs->v6addrs.src));
966  		memcpy(&key_addrs->v6addrs.dst, &flow_keys->ipv6_dst,
967  		       sizeof(key_addrs->v6addrs.dst));
968  		key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
969  	}
970  
971  	if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS))
972  		key_ports = skb_flow_dissector_target(flow_dissector,
973  						      FLOW_DISSECTOR_KEY_PORTS,
974  						      target_container);
975  	else if (dissector_uses_key(flow_dissector,
976  				    FLOW_DISSECTOR_KEY_PORTS_RANGE))
977  		key_ports = skb_flow_dissector_target(flow_dissector,
978  						      FLOW_DISSECTOR_KEY_PORTS_RANGE,
979  						      target_container);
980  
981  	if (key_ports) {
982  		key_ports->src = flow_keys->sport;
983  		key_ports->dst = flow_keys->dport;
984  	}
985  
986  	if (dissector_uses_key(flow_dissector,
987  			       FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
988  		key_tags = skb_flow_dissector_target(flow_dissector,
989  						     FLOW_DISSECTOR_KEY_FLOW_LABEL,
990  						     target_container);
991  		key_tags->flow_label = ntohl(flow_keys->flow_label);
992  	}
993  }
994  
bpf_flow_dissect(struct bpf_prog * prog,struct bpf_flow_dissector * ctx,__be16 proto,int nhoff,int hlen,unsigned int flags)995  u32 bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
996  		     __be16 proto, int nhoff, int hlen, unsigned int flags)
997  {
998  	struct bpf_flow_keys *flow_keys = ctx->flow_keys;
999  	u32 result;
1000  
1001  	/* Pass parameters to the BPF program */
1002  	memset(flow_keys, 0, sizeof(*flow_keys));
1003  	flow_keys->n_proto = proto;
1004  	flow_keys->nhoff = nhoff;
1005  	flow_keys->thoff = flow_keys->nhoff;
1006  
1007  	BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG !=
1008  		     (int)FLOW_DISSECTOR_F_PARSE_1ST_FRAG);
1009  	BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL !=
1010  		     (int)FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
1011  	BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP !=
1012  		     (int)FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1013  	flow_keys->flags = flags;
1014  
1015  	result = bpf_prog_run_pin_on_cpu(prog, ctx);
1016  
1017  	flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, nhoff, hlen);
1018  	flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
1019  				   flow_keys->nhoff, hlen);
1020  
1021  	return result;
1022  }
1023  
is_pppoe_ses_hdr_valid(const struct pppoe_hdr * hdr)1024  static bool is_pppoe_ses_hdr_valid(const struct pppoe_hdr *hdr)
1025  {
1026  	return hdr->ver == 1 && hdr->type == 1 && hdr->code == 0;
1027  }
1028  
1029  /**
1030   * __skb_flow_dissect - extract the flow_keys struct and return it
1031   * @net: associated network namespace, derived from @skb if NULL
1032   * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
1033   * @flow_dissector: list of keys to dissect
1034   * @target_container: target structure to put dissected values into
1035   * @data: raw buffer pointer to the packet, if NULL use skb->data
1036   * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
1037   * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
1038   * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
1039   * @flags: flags that control the dissection process, e.g.
1040   *         FLOW_DISSECTOR_F_STOP_AT_ENCAP.
1041   *
1042   * The function will try to retrieve individual keys into target specified
1043   * by flow_dissector from either the skbuff or a raw buffer specified by the
1044   * rest parameters.
1045   *
1046   * Caller must take care of zeroing target container memory.
1047   */
__skb_flow_dissect(const struct net * net,const struct sk_buff * skb,struct flow_dissector * flow_dissector,void * target_container,const void * data,__be16 proto,int nhoff,int hlen,unsigned int flags)1048  bool __skb_flow_dissect(const struct net *net,
1049  			const struct sk_buff *skb,
1050  			struct flow_dissector *flow_dissector,
1051  			void *target_container, const void *data,
1052  			__be16 proto, int nhoff, int hlen, unsigned int flags)
1053  {
1054  	struct flow_dissector_key_control *key_control;
1055  	struct flow_dissector_key_basic *key_basic;
1056  	struct flow_dissector_key_addrs *key_addrs;
1057  	struct flow_dissector_key_tags *key_tags;
1058  	struct flow_dissector_key_vlan *key_vlan;
1059  	enum flow_dissect_ret fdret;
1060  	enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
1061  	bool mpls_el = false;
1062  	int mpls_lse = 0;
1063  	int num_hdrs = 0;
1064  	u8 ip_proto = 0;
1065  	bool ret;
1066  
1067  	if (!data) {
1068  		data = skb->data;
1069  		proto = skb_vlan_tag_present(skb) ?
1070  			 skb->vlan_proto : skb->protocol;
1071  		nhoff = skb_network_offset(skb);
1072  		hlen = skb_headlen(skb);
1073  #if IS_ENABLED(CONFIG_NET_DSA)
1074  		if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) &&
1075  			     proto == htons(ETH_P_XDSA))) {
1076  			struct metadata_dst *md_dst = skb_metadata_dst(skb);
1077  			const struct dsa_device_ops *ops;
1078  			int offset = 0;
1079  
1080  			ops = skb->dev->dsa_ptr->tag_ops;
1081  			/* Only DSA header taggers break flow dissection */
1082  			if (ops->needed_headroom &&
1083  			    (!md_dst || md_dst->type != METADATA_HW_PORT_MUX)) {
1084  				if (ops->flow_dissect)
1085  					ops->flow_dissect(skb, &proto, &offset);
1086  				else
1087  					dsa_tag_generic_flow_dissect(skb,
1088  								     &proto,
1089  								     &offset);
1090  				hlen -= offset;
1091  				nhoff += offset;
1092  			}
1093  		}
1094  #endif
1095  	}
1096  
1097  	/* It is ensured by skb_flow_dissector_init() that control key will
1098  	 * be always present.
1099  	 */
1100  	key_control = skb_flow_dissector_target(flow_dissector,
1101  						FLOW_DISSECTOR_KEY_CONTROL,
1102  						target_container);
1103  
1104  	/* It is ensured by skb_flow_dissector_init() that basic key will
1105  	 * be always present.
1106  	 */
1107  	key_basic = skb_flow_dissector_target(flow_dissector,
1108  					      FLOW_DISSECTOR_KEY_BASIC,
1109  					      target_container);
1110  
1111  	if (skb) {
1112  		if (!net) {
1113  			if (skb->dev)
1114  				net = dev_net(skb->dev);
1115  			else if (skb->sk)
1116  				net = sock_net(skb->sk);
1117  		}
1118  	}
1119  
1120  	DEBUG_NET_WARN_ON_ONCE(!net);
1121  	if (net) {
1122  		enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR;
1123  		struct bpf_prog_array *run_array;
1124  
1125  		rcu_read_lock();
1126  		run_array = rcu_dereference(init_net.bpf.run_array[type]);
1127  		if (!run_array)
1128  			run_array = rcu_dereference(net->bpf.run_array[type]);
1129  
1130  		if (run_array) {
1131  			struct bpf_flow_keys flow_keys;
1132  			struct bpf_flow_dissector ctx = {
1133  				.flow_keys = &flow_keys,
1134  				.data = data,
1135  				.data_end = data + hlen,
1136  			};
1137  			__be16 n_proto = proto;
1138  			struct bpf_prog *prog;
1139  			u32 result;
1140  
1141  			if (skb) {
1142  				ctx.skb = skb;
1143  				/* we can't use 'proto' in the skb case
1144  				 * because it might be set to skb->vlan_proto
1145  				 * which has been pulled from the data
1146  				 */
1147  				n_proto = skb->protocol;
1148  			}
1149  
1150  			prog = READ_ONCE(run_array->items[0].prog);
1151  			result = bpf_flow_dissect(prog, &ctx, n_proto, nhoff,
1152  						  hlen, flags);
1153  			if (result == BPF_FLOW_DISSECTOR_CONTINUE)
1154  				goto dissect_continue;
1155  			__skb_flow_bpf_to_target(&flow_keys, flow_dissector,
1156  						 target_container);
1157  			rcu_read_unlock();
1158  			return result == BPF_OK;
1159  		}
1160  dissect_continue:
1161  		rcu_read_unlock();
1162  	}
1163  
1164  	if (dissector_uses_key(flow_dissector,
1165  			       FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
1166  		struct ethhdr *eth = eth_hdr(skb);
1167  		struct flow_dissector_key_eth_addrs *key_eth_addrs;
1168  
1169  		key_eth_addrs = skb_flow_dissector_target(flow_dissector,
1170  							  FLOW_DISSECTOR_KEY_ETH_ADDRS,
1171  							  target_container);
1172  		memcpy(key_eth_addrs, eth, sizeof(*key_eth_addrs));
1173  	}
1174  
1175  	if (dissector_uses_key(flow_dissector,
1176  			       FLOW_DISSECTOR_KEY_NUM_OF_VLANS)) {
1177  		struct flow_dissector_key_num_of_vlans *key_num_of_vlans;
1178  
1179  		key_num_of_vlans = skb_flow_dissector_target(flow_dissector,
1180  							     FLOW_DISSECTOR_KEY_NUM_OF_VLANS,
1181  							     target_container);
1182  		key_num_of_vlans->num_of_vlans = 0;
1183  	}
1184  
1185  proto_again:
1186  	fdret = FLOW_DISSECT_RET_CONTINUE;
1187  
1188  	switch (proto) {
1189  	case htons(ETH_P_IP): {
1190  		const struct iphdr *iph;
1191  		struct iphdr _iph;
1192  
1193  		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
1194  		if (!iph || iph->ihl < 5) {
1195  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1196  			break;
1197  		}
1198  
1199  		nhoff += iph->ihl * 4;
1200  
1201  		ip_proto = iph->protocol;
1202  
1203  		if (dissector_uses_key(flow_dissector,
1204  				       FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
1205  			key_addrs = skb_flow_dissector_target(flow_dissector,
1206  							      FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1207  							      target_container);
1208  
1209  			memcpy(&key_addrs->v4addrs.src, &iph->saddr,
1210  			       sizeof(key_addrs->v4addrs.src));
1211  			memcpy(&key_addrs->v4addrs.dst, &iph->daddr,
1212  			       sizeof(key_addrs->v4addrs.dst));
1213  			key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1214  		}
1215  
1216  		__skb_flow_dissect_ipv4(skb, flow_dissector,
1217  					target_container, data, iph);
1218  
1219  		if (ip_is_fragment(iph)) {
1220  			key_control->flags |= FLOW_DIS_IS_FRAGMENT;
1221  
1222  			if (iph->frag_off & htons(IP_OFFSET)) {
1223  				fdret = FLOW_DISSECT_RET_OUT_GOOD;
1224  				break;
1225  			} else {
1226  				key_control->flags |= FLOW_DIS_FIRST_FRAG;
1227  				if (!(flags &
1228  				      FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) {
1229  					fdret = FLOW_DISSECT_RET_OUT_GOOD;
1230  					break;
1231  				}
1232  			}
1233  		}
1234  
1235  		break;
1236  	}
1237  	case htons(ETH_P_IPV6): {
1238  		const struct ipv6hdr *iph;
1239  		struct ipv6hdr _iph;
1240  
1241  		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
1242  		if (!iph) {
1243  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1244  			break;
1245  		}
1246  
1247  		ip_proto = iph->nexthdr;
1248  		nhoff += sizeof(struct ipv6hdr);
1249  
1250  		if (dissector_uses_key(flow_dissector,
1251  				       FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
1252  			key_addrs = skb_flow_dissector_target(flow_dissector,
1253  							      FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1254  							      target_container);
1255  
1256  			memcpy(&key_addrs->v6addrs.src, &iph->saddr,
1257  			       sizeof(key_addrs->v6addrs.src));
1258  			memcpy(&key_addrs->v6addrs.dst, &iph->daddr,
1259  			       sizeof(key_addrs->v6addrs.dst));
1260  			key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1261  		}
1262  
1263  		if ((dissector_uses_key(flow_dissector,
1264  					FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
1265  		     (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
1266  		    ip6_flowlabel(iph)) {
1267  			__be32 flow_label = ip6_flowlabel(iph);
1268  
1269  			if (dissector_uses_key(flow_dissector,
1270  					       FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
1271  				key_tags = skb_flow_dissector_target(flow_dissector,
1272  								     FLOW_DISSECTOR_KEY_FLOW_LABEL,
1273  								     target_container);
1274  				key_tags->flow_label = ntohl(flow_label);
1275  			}
1276  			if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) {
1277  				fdret = FLOW_DISSECT_RET_OUT_GOOD;
1278  				break;
1279  			}
1280  		}
1281  
1282  		__skb_flow_dissect_ipv6(skb, flow_dissector,
1283  					target_container, data, iph);
1284  
1285  		break;
1286  	}
1287  	case htons(ETH_P_8021AD):
1288  	case htons(ETH_P_8021Q): {
1289  		const struct vlan_hdr *vlan = NULL;
1290  		struct vlan_hdr _vlan;
1291  		__be16 saved_vlan_tpid = proto;
1292  
1293  		if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX &&
1294  		    skb && skb_vlan_tag_present(skb)) {
1295  			proto = skb->protocol;
1296  		} else {
1297  			vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
1298  						    data, hlen, &_vlan);
1299  			if (!vlan) {
1300  				fdret = FLOW_DISSECT_RET_OUT_BAD;
1301  				break;
1302  			}
1303  
1304  			proto = vlan->h_vlan_encapsulated_proto;
1305  			nhoff += sizeof(*vlan);
1306  		}
1307  
1308  		if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_NUM_OF_VLANS) &&
1309  		    !(key_control->flags & FLOW_DIS_ENCAPSULATION)) {
1310  			struct flow_dissector_key_num_of_vlans *key_nvs;
1311  
1312  			key_nvs = skb_flow_dissector_target(flow_dissector,
1313  							    FLOW_DISSECTOR_KEY_NUM_OF_VLANS,
1314  							    target_container);
1315  			key_nvs->num_of_vlans++;
1316  		}
1317  
1318  		if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) {
1319  			dissector_vlan = FLOW_DISSECTOR_KEY_VLAN;
1320  		} else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) {
1321  			dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN;
1322  		} else {
1323  			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1324  			break;
1325  		}
1326  
1327  		if (dissector_uses_key(flow_dissector, dissector_vlan)) {
1328  			key_vlan = skb_flow_dissector_target(flow_dissector,
1329  							     dissector_vlan,
1330  							     target_container);
1331  
1332  			if (!vlan) {
1333  				key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
1334  				key_vlan->vlan_priority = skb_vlan_tag_get_prio(skb);
1335  			} else {
1336  				key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
1337  					VLAN_VID_MASK;
1338  				key_vlan->vlan_priority =
1339  					(ntohs(vlan->h_vlan_TCI) &
1340  					 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
1341  			}
1342  			key_vlan->vlan_tpid = saved_vlan_tpid;
1343  			key_vlan->vlan_eth_type = proto;
1344  		}
1345  
1346  		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1347  		break;
1348  	}
1349  	case htons(ETH_P_PPP_SES): {
1350  		struct {
1351  			struct pppoe_hdr hdr;
1352  			__be16 proto;
1353  		} *hdr, _hdr;
1354  		u16 ppp_proto;
1355  
1356  		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
1357  		if (!hdr) {
1358  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1359  			break;
1360  		}
1361  
1362  		if (!is_pppoe_ses_hdr_valid(&hdr->hdr)) {
1363  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1364  			break;
1365  		}
1366  
1367  		/* least significant bit of the most significant octet
1368  		 * indicates if protocol field was compressed
1369  		 */
1370  		ppp_proto = ntohs(hdr->proto);
1371  		if (ppp_proto & 0x0100) {
1372  			ppp_proto = ppp_proto >> 8;
1373  			nhoff += PPPOE_SES_HLEN - 1;
1374  		} else {
1375  			nhoff += PPPOE_SES_HLEN;
1376  		}
1377  
1378  		if (ppp_proto == PPP_IP) {
1379  			proto = htons(ETH_P_IP);
1380  			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1381  		} else if (ppp_proto == PPP_IPV6) {
1382  			proto = htons(ETH_P_IPV6);
1383  			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1384  		} else if (ppp_proto == PPP_MPLS_UC) {
1385  			proto = htons(ETH_P_MPLS_UC);
1386  			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1387  		} else if (ppp_proto == PPP_MPLS_MC) {
1388  			proto = htons(ETH_P_MPLS_MC);
1389  			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1390  		} else if (ppp_proto_is_valid(ppp_proto)) {
1391  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1392  		} else {
1393  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1394  			break;
1395  		}
1396  
1397  		if (dissector_uses_key(flow_dissector,
1398  				       FLOW_DISSECTOR_KEY_PPPOE)) {
1399  			struct flow_dissector_key_pppoe *key_pppoe;
1400  
1401  			key_pppoe = skb_flow_dissector_target(flow_dissector,
1402  							      FLOW_DISSECTOR_KEY_PPPOE,
1403  							      target_container);
1404  			key_pppoe->session_id = hdr->hdr.sid;
1405  			key_pppoe->ppp_proto = htons(ppp_proto);
1406  			key_pppoe->type = htons(ETH_P_PPP_SES);
1407  		}
1408  		break;
1409  	}
1410  	case htons(ETH_P_TIPC): {
1411  		struct tipc_basic_hdr *hdr, _hdr;
1412  
1413  		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr),
1414  					   data, hlen, &_hdr);
1415  		if (!hdr) {
1416  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1417  			break;
1418  		}
1419  
1420  		if (dissector_uses_key(flow_dissector,
1421  				       FLOW_DISSECTOR_KEY_TIPC)) {
1422  			key_addrs = skb_flow_dissector_target(flow_dissector,
1423  							      FLOW_DISSECTOR_KEY_TIPC,
1424  							      target_container);
1425  			key_addrs->tipckey.key = tipc_hdr_rps_key(hdr);
1426  			key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC;
1427  		}
1428  		fdret = FLOW_DISSECT_RET_OUT_GOOD;
1429  		break;
1430  	}
1431  
1432  	case htons(ETH_P_MPLS_UC):
1433  	case htons(ETH_P_MPLS_MC):
1434  		fdret = __skb_flow_dissect_mpls(skb, flow_dissector,
1435  						target_container, data,
1436  						nhoff, hlen, mpls_lse,
1437  						&mpls_el);
1438  		nhoff += sizeof(struct mpls_label);
1439  		mpls_lse++;
1440  		break;
1441  	case htons(ETH_P_FCOE):
1442  		if ((hlen - nhoff) < FCOE_HEADER_LEN) {
1443  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1444  			break;
1445  		}
1446  
1447  		nhoff += FCOE_HEADER_LEN;
1448  		fdret = FLOW_DISSECT_RET_OUT_GOOD;
1449  		break;
1450  
1451  	case htons(ETH_P_ARP):
1452  	case htons(ETH_P_RARP):
1453  		fdret = __skb_flow_dissect_arp(skb, flow_dissector,
1454  					       target_container, data,
1455  					       nhoff, hlen);
1456  		break;
1457  
1458  	case htons(ETH_P_BATMAN):
1459  		fdret = __skb_flow_dissect_batadv(skb, key_control, data,
1460  						  &proto, &nhoff, hlen, flags);
1461  		break;
1462  
1463  	case htons(ETH_P_1588): {
1464  		struct ptp_header *hdr, _hdr;
1465  
1466  		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
1467  					   hlen, &_hdr);
1468  		if (!hdr) {
1469  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1470  			break;
1471  		}
1472  
1473  		nhoff += sizeof(struct ptp_header);
1474  		fdret = FLOW_DISSECT_RET_OUT_GOOD;
1475  		break;
1476  	}
1477  
1478  	case htons(ETH_P_PRP):
1479  	case htons(ETH_P_HSR): {
1480  		struct hsr_tag *hdr, _hdr;
1481  
1482  		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen,
1483  					   &_hdr);
1484  		if (!hdr) {
1485  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1486  			break;
1487  		}
1488  
1489  		proto = hdr->encap_proto;
1490  		nhoff += HSR_HLEN;
1491  		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1492  		break;
1493  	}
1494  
1495  	case htons(ETH_P_CFM):
1496  		fdret = __skb_flow_dissect_cfm(skb, flow_dissector,
1497  					       target_container, data,
1498  					       nhoff, hlen);
1499  		break;
1500  
1501  	default:
1502  		fdret = FLOW_DISSECT_RET_OUT_BAD;
1503  		break;
1504  	}
1505  
1506  	/* Process result of proto processing */
1507  	switch (fdret) {
1508  	case FLOW_DISSECT_RET_OUT_GOOD:
1509  		goto out_good;
1510  	case FLOW_DISSECT_RET_PROTO_AGAIN:
1511  		if (skb_flow_dissect_allowed(&num_hdrs))
1512  			goto proto_again;
1513  		goto out_good;
1514  	case FLOW_DISSECT_RET_CONTINUE:
1515  	case FLOW_DISSECT_RET_IPPROTO_AGAIN:
1516  		break;
1517  	case FLOW_DISSECT_RET_OUT_BAD:
1518  	default:
1519  		goto out_bad;
1520  	}
1521  
1522  ip_proto_again:
1523  	fdret = FLOW_DISSECT_RET_CONTINUE;
1524  
1525  	switch (ip_proto) {
1526  	case IPPROTO_GRE:
1527  		if (flags & FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP) {
1528  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1529  			break;
1530  		}
1531  
1532  		fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector,
1533  					       target_container, data,
1534  					       &proto, &nhoff, &hlen, flags);
1535  		break;
1536  
1537  	case NEXTHDR_HOP:
1538  	case NEXTHDR_ROUTING:
1539  	case NEXTHDR_DEST: {
1540  		u8 _opthdr[2], *opthdr;
1541  
1542  		if (proto != htons(ETH_P_IPV6))
1543  			break;
1544  
1545  		opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
1546  					      data, hlen, &_opthdr);
1547  		if (!opthdr) {
1548  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1549  			break;
1550  		}
1551  
1552  		ip_proto = opthdr[0];
1553  		nhoff += (opthdr[1] + 1) << 3;
1554  
1555  		fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
1556  		break;
1557  	}
1558  	case NEXTHDR_FRAGMENT: {
1559  		struct frag_hdr _fh, *fh;
1560  
1561  		if (proto != htons(ETH_P_IPV6))
1562  			break;
1563  
1564  		fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
1565  					  data, hlen, &_fh);
1566  
1567  		if (!fh) {
1568  			fdret = FLOW_DISSECT_RET_OUT_BAD;
1569  			break;
1570  		}
1571  
1572  		key_control->flags |= FLOW_DIS_IS_FRAGMENT;
1573  
1574  		nhoff += sizeof(_fh);
1575  		ip_proto = fh->nexthdr;
1576  
1577  		if (!(fh->frag_off & htons(IP6_OFFSET))) {
1578  			key_control->flags |= FLOW_DIS_FIRST_FRAG;
1579  			if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {
1580  				fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
1581  				break;
1582  			}
1583  		}
1584  
1585  		fdret = FLOW_DISSECT_RET_OUT_GOOD;
1586  		break;
1587  	}
1588  	case IPPROTO_IPIP:
1589  		if (flags & FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP) {
1590  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1591  			break;
1592  		}
1593  
1594  		proto = htons(ETH_P_IP);
1595  
1596  		key_control->flags |= FLOW_DIS_ENCAPSULATION;
1597  		if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
1598  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1599  			break;
1600  		}
1601  
1602  		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1603  		break;
1604  
1605  	case IPPROTO_IPV6:
1606  		if (flags & FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP) {
1607  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1608  			break;
1609  		}
1610  
1611  		proto = htons(ETH_P_IPV6);
1612  
1613  		key_control->flags |= FLOW_DIS_ENCAPSULATION;
1614  		if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
1615  			fdret = FLOW_DISSECT_RET_OUT_GOOD;
1616  			break;
1617  		}
1618  
1619  		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1620  		break;
1621  
1622  
1623  	case IPPROTO_MPLS:
1624  		proto = htons(ETH_P_MPLS_UC);
1625  		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
1626  		break;
1627  
1628  	case IPPROTO_TCP:
1629  		__skb_flow_dissect_tcp(skb, flow_dissector, target_container,
1630  				       data, nhoff, hlen);
1631  		break;
1632  
1633  	case IPPROTO_ICMP:
1634  	case IPPROTO_ICMPV6:
1635  		__skb_flow_dissect_icmp(skb, flow_dissector, target_container,
1636  					data, nhoff, hlen);
1637  		break;
1638  	case IPPROTO_L2TP:
1639  		__skb_flow_dissect_l2tpv3(skb, flow_dissector, target_container,
1640  					  data, nhoff, hlen);
1641  		break;
1642  	case IPPROTO_ESP:
1643  		__skb_flow_dissect_esp(skb, flow_dissector, target_container,
1644  				       data, nhoff, hlen);
1645  		break;
1646  	case IPPROTO_AH:
1647  		__skb_flow_dissect_ah(skb, flow_dissector, target_container,
1648  				      data, nhoff, hlen);
1649  		break;
1650  	default:
1651  		break;
1652  	}
1653  
1654  	if (!(key_control->flags & FLOW_DIS_IS_FRAGMENT))
1655  		__skb_flow_dissect_ports(skb, flow_dissector, target_container,
1656  					 data, nhoff, ip_proto, hlen);
1657  
1658  	/* Process result of IP proto processing */
1659  	switch (fdret) {
1660  	case FLOW_DISSECT_RET_PROTO_AGAIN:
1661  		if (skb_flow_dissect_allowed(&num_hdrs))
1662  			goto proto_again;
1663  		break;
1664  	case FLOW_DISSECT_RET_IPPROTO_AGAIN:
1665  		if (skb_flow_dissect_allowed(&num_hdrs))
1666  			goto ip_proto_again;
1667  		break;
1668  	case FLOW_DISSECT_RET_OUT_GOOD:
1669  	case FLOW_DISSECT_RET_CONTINUE:
1670  		break;
1671  	case FLOW_DISSECT_RET_OUT_BAD:
1672  	default:
1673  		goto out_bad;
1674  	}
1675  
1676  out_good:
1677  	ret = true;
1678  
1679  out:
1680  	key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
1681  	key_basic->n_proto = proto;
1682  	key_basic->ip_proto = ip_proto;
1683  
1684  	return ret;
1685  
1686  out_bad:
1687  	ret = false;
1688  	goto out;
1689  }
1690  EXPORT_SYMBOL(__skb_flow_dissect);
1691  
1692  static siphash_aligned_key_t hashrnd;
__flow_hash_secret_init(void)1693  static __always_inline void __flow_hash_secret_init(void)
1694  {
1695  	net_get_random_once(&hashrnd, sizeof(hashrnd));
1696  }
1697  
flow_keys_hash_start(const struct flow_keys * flow)1698  static const void *flow_keys_hash_start(const struct flow_keys *flow)
1699  {
1700  	BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % SIPHASH_ALIGNMENT);
1701  	return &flow->FLOW_KEYS_HASH_START_FIELD;
1702  }
1703  
flow_keys_hash_length(const struct flow_keys * flow)1704  static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
1705  {
1706  	size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
1707  
1708  	BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
1709  
1710  	switch (flow->control.addr_type) {
1711  	case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1712  		diff -= sizeof(flow->addrs.v4addrs);
1713  		break;
1714  	case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1715  		diff -= sizeof(flow->addrs.v6addrs);
1716  		break;
1717  	case FLOW_DISSECTOR_KEY_TIPC:
1718  		diff -= sizeof(flow->addrs.tipckey);
1719  		break;
1720  	}
1721  	return sizeof(*flow) - diff;
1722  }
1723  
flow_get_u32_src(const struct flow_keys * flow)1724  __be32 flow_get_u32_src(const struct flow_keys *flow)
1725  {
1726  	switch (flow->control.addr_type) {
1727  	case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1728  		return flow->addrs.v4addrs.src;
1729  	case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1730  		return (__force __be32)ipv6_addr_hash(
1731  			&flow->addrs.v6addrs.src);
1732  	case FLOW_DISSECTOR_KEY_TIPC:
1733  		return flow->addrs.tipckey.key;
1734  	default:
1735  		return 0;
1736  	}
1737  }
1738  EXPORT_SYMBOL(flow_get_u32_src);
1739  
flow_get_u32_dst(const struct flow_keys * flow)1740  __be32 flow_get_u32_dst(const struct flow_keys *flow)
1741  {
1742  	switch (flow->control.addr_type) {
1743  	case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1744  		return flow->addrs.v4addrs.dst;
1745  	case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1746  		return (__force __be32)ipv6_addr_hash(
1747  			&flow->addrs.v6addrs.dst);
1748  	default:
1749  		return 0;
1750  	}
1751  }
1752  EXPORT_SYMBOL(flow_get_u32_dst);
1753  
1754  /* Sort the source and destination IP and the ports,
1755   * to have consistent hash within the two directions
1756   */
__flow_hash_consistentify(struct flow_keys * keys)1757  static inline void __flow_hash_consistentify(struct flow_keys *keys)
1758  {
1759  	int addr_diff, i;
1760  
1761  	switch (keys->control.addr_type) {
1762  	case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
1763  		if ((__force u32)keys->addrs.v4addrs.dst <
1764  		    (__force u32)keys->addrs.v4addrs.src)
1765  			swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
1766  
1767  		if ((__force u16)keys->ports.dst <
1768  		    (__force u16)keys->ports.src) {
1769  			swap(keys->ports.src, keys->ports.dst);
1770  		}
1771  		break;
1772  	case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
1773  		addr_diff = memcmp(&keys->addrs.v6addrs.dst,
1774  				   &keys->addrs.v6addrs.src,
1775  				   sizeof(keys->addrs.v6addrs.dst));
1776  		if (addr_diff < 0) {
1777  			for (i = 0; i < 4; i++)
1778  				swap(keys->addrs.v6addrs.src.s6_addr32[i],
1779  				     keys->addrs.v6addrs.dst.s6_addr32[i]);
1780  		}
1781  		if ((__force u16)keys->ports.dst <
1782  		    (__force u16)keys->ports.src) {
1783  			swap(keys->ports.src, keys->ports.dst);
1784  		}
1785  		break;
1786  	}
1787  }
1788  
__flow_hash_from_keys(struct flow_keys * keys,const siphash_key_t * keyval)1789  static inline u32 __flow_hash_from_keys(struct flow_keys *keys,
1790  					const siphash_key_t *keyval)
1791  {
1792  	u32 hash;
1793  
1794  	__flow_hash_consistentify(keys);
1795  
1796  	hash = siphash(flow_keys_hash_start(keys),
1797  		       flow_keys_hash_length(keys), keyval);
1798  	if (!hash)
1799  		hash = 1;
1800  
1801  	return hash;
1802  }
1803  
flow_hash_from_keys(struct flow_keys * keys)1804  u32 flow_hash_from_keys(struct flow_keys *keys)
1805  {
1806  	__flow_hash_secret_init();
1807  	return __flow_hash_from_keys(keys, &hashrnd);
1808  }
1809  EXPORT_SYMBOL(flow_hash_from_keys);
1810  
flow_hash_from_keys_seed(struct flow_keys * keys,const siphash_key_t * keyval)1811  u32 flow_hash_from_keys_seed(struct flow_keys *keys,
1812  			     const siphash_key_t *keyval)
1813  {
1814  	return __flow_hash_from_keys(keys, keyval);
1815  }
1816  EXPORT_SYMBOL(flow_hash_from_keys_seed);
1817  
___skb_get_hash(const struct sk_buff * skb,struct flow_keys * keys,const siphash_key_t * keyval)1818  static inline u32 ___skb_get_hash(const struct sk_buff *skb,
1819  				  struct flow_keys *keys,
1820  				  const siphash_key_t *keyval)
1821  {
1822  	skb_flow_dissect_flow_keys(skb, keys,
1823  				   FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
1824  
1825  	return __flow_hash_from_keys(keys, keyval);
1826  }
1827  
1828  struct _flow_keys_digest_data {
1829  	__be16	n_proto;
1830  	u8	ip_proto;
1831  	u8	padding;
1832  	__be32	ports;
1833  	__be32	src;
1834  	__be32	dst;
1835  };
1836  
make_flow_keys_digest(struct flow_keys_digest * digest,const struct flow_keys * flow)1837  void make_flow_keys_digest(struct flow_keys_digest *digest,
1838  			   const struct flow_keys *flow)
1839  {
1840  	struct _flow_keys_digest_data *data =
1841  	    (struct _flow_keys_digest_data *)digest;
1842  
1843  	BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
1844  
1845  	memset(digest, 0, sizeof(*digest));
1846  
1847  	data->n_proto = flow->basic.n_proto;
1848  	data->ip_proto = flow->basic.ip_proto;
1849  	data->ports = flow->ports.ports;
1850  	data->src = flow->addrs.v4addrs.src;
1851  	data->dst = flow->addrs.v4addrs.dst;
1852  }
1853  EXPORT_SYMBOL(make_flow_keys_digest);
1854  
1855  static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
1856  
__skb_get_hash_symmetric_net(const struct net * net,const struct sk_buff * skb)1857  u32 __skb_get_hash_symmetric_net(const struct net *net, const struct sk_buff *skb)
1858  {
1859  	struct flow_keys keys;
1860  
1861  	__flow_hash_secret_init();
1862  
1863  	memset(&keys, 0, sizeof(keys));
1864  	__skb_flow_dissect(net, skb, &flow_keys_dissector_symmetric,
1865  			   &keys, NULL, 0, 0, 0, 0);
1866  
1867  	return __flow_hash_from_keys(&keys, &hashrnd);
1868  }
1869  EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric_net);
1870  
1871  /**
1872   * __skb_get_hash_net: calculate a flow hash
1873   * @net: associated network namespace, derived from @skb if NULL
1874   * @skb: sk_buff to calculate flow hash from
1875   *
1876   * This function calculates a flow hash based on src/dst addresses
1877   * and src/dst port numbers.  Sets hash in skb to non-zero hash value
1878   * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
1879   * if hash is a canonical 4-tuple hash over transport ports.
1880   */
__skb_get_hash_net(const struct net * net,struct sk_buff * skb)1881  void __skb_get_hash_net(const struct net *net, struct sk_buff *skb)
1882  {
1883  	struct flow_keys keys;
1884  	u32 hash;
1885  
1886  	memset(&keys, 0, sizeof(keys));
1887  
1888  	__skb_flow_dissect(net, skb, &flow_keys_dissector,
1889  			   &keys, NULL, 0, 0, 0,
1890  			   FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
1891  
1892  	__flow_hash_secret_init();
1893  
1894  	hash = __flow_hash_from_keys(&keys, &hashrnd);
1895  
1896  	__skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1897  }
1898  EXPORT_SYMBOL(__skb_get_hash_net);
1899  
skb_get_hash_perturb(const struct sk_buff * skb,const siphash_key_t * perturb)1900  __u32 skb_get_hash_perturb(const struct sk_buff *skb,
1901  			   const siphash_key_t *perturb)
1902  {
1903  	struct flow_keys keys;
1904  
1905  	return ___skb_get_hash(skb, &keys, perturb);
1906  }
1907  EXPORT_SYMBOL(skb_get_hash_perturb);
1908  
__skb_get_poff(const struct sk_buff * skb,const void * data,const struct flow_keys_basic * keys,int hlen)1909  u32 __skb_get_poff(const struct sk_buff *skb, const void *data,
1910  		   const struct flow_keys_basic *keys, int hlen)
1911  {
1912  	u32 poff = keys->control.thoff;
1913  
1914  	/* skip L4 headers for fragments after the first */
1915  	if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
1916  	    !(keys->control.flags & FLOW_DIS_FIRST_FRAG))
1917  		return poff;
1918  
1919  	switch (keys->basic.ip_proto) {
1920  	case IPPROTO_TCP: {
1921  		/* access doff as u8 to avoid unaligned access */
1922  		const u8 *doff;
1923  		u8 _doff;
1924  
1925  		doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
1926  					    data, hlen, &_doff);
1927  		if (!doff)
1928  			return poff;
1929  
1930  		poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
1931  		break;
1932  	}
1933  	case IPPROTO_UDP:
1934  	case IPPROTO_UDPLITE:
1935  		poff += sizeof(struct udphdr);
1936  		break;
1937  	/* For the rest, we do not really care about header
1938  	 * extensions at this point for now.
1939  	 */
1940  	case IPPROTO_ICMP:
1941  		poff += sizeof(struct icmphdr);
1942  		break;
1943  	case IPPROTO_ICMPV6:
1944  		poff += sizeof(struct icmp6hdr);
1945  		break;
1946  	case IPPROTO_IGMP:
1947  		poff += sizeof(struct igmphdr);
1948  		break;
1949  	case IPPROTO_DCCP:
1950  		poff += sizeof(struct dccp_hdr);
1951  		break;
1952  	case IPPROTO_SCTP:
1953  		poff += sizeof(struct sctphdr);
1954  		break;
1955  	}
1956  
1957  	return poff;
1958  }
1959  
1960  /**
1961   * skb_get_poff - get the offset to the payload
1962   * @skb: sk_buff to get the payload offset from
1963   *
1964   * The function will get the offset to the payload as far as it could
1965   * be dissected.  The main user is currently BPF, so that we can dynamically
1966   * truncate packets without needing to push actual payload to the user
1967   * space and can analyze headers only, instead.
1968   */
skb_get_poff(const struct sk_buff * skb)1969  u32 skb_get_poff(const struct sk_buff *skb)
1970  {
1971  	struct flow_keys_basic keys;
1972  
1973  	if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
1974  					      NULL, 0, 0, 0, 0))
1975  		return 0;
1976  
1977  	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
1978  }
1979  
__get_hash_from_flowi6(const struct flowi6 * fl6,struct flow_keys * keys)1980  __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
1981  {
1982  	memset(keys, 0, sizeof(*keys));
1983  
1984  	memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
1985  	    sizeof(keys->addrs.v6addrs.src));
1986  	memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
1987  	    sizeof(keys->addrs.v6addrs.dst));
1988  	keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1989  	keys->ports.src = fl6->fl6_sport;
1990  	keys->ports.dst = fl6->fl6_dport;
1991  	keys->keyid.keyid = fl6->fl6_gre_key;
1992  	keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
1993  	keys->basic.ip_proto = fl6->flowi6_proto;
1994  
1995  	return flow_hash_from_keys(keys);
1996  }
1997  EXPORT_SYMBOL(__get_hash_from_flowi6);
1998  
1999  static const struct flow_dissector_key flow_keys_dissector_keys[] = {
2000  	{
2001  		.key_id = FLOW_DISSECTOR_KEY_CONTROL,
2002  		.offset = offsetof(struct flow_keys, control),
2003  	},
2004  	{
2005  		.key_id = FLOW_DISSECTOR_KEY_BASIC,
2006  		.offset = offsetof(struct flow_keys, basic),
2007  	},
2008  	{
2009  		.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
2010  		.offset = offsetof(struct flow_keys, addrs.v4addrs),
2011  	},
2012  	{
2013  		.key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
2014  		.offset = offsetof(struct flow_keys, addrs.v6addrs),
2015  	},
2016  	{
2017  		.key_id = FLOW_DISSECTOR_KEY_TIPC,
2018  		.offset = offsetof(struct flow_keys, addrs.tipckey),
2019  	},
2020  	{
2021  		.key_id = FLOW_DISSECTOR_KEY_PORTS,
2022  		.offset = offsetof(struct flow_keys, ports),
2023  	},
2024  	{
2025  		.key_id = FLOW_DISSECTOR_KEY_VLAN,
2026  		.offset = offsetof(struct flow_keys, vlan),
2027  	},
2028  	{
2029  		.key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
2030  		.offset = offsetof(struct flow_keys, tags),
2031  	},
2032  	{
2033  		.key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
2034  		.offset = offsetof(struct flow_keys, keyid),
2035  	},
2036  };
2037  
2038  static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
2039  	{
2040  		.key_id = FLOW_DISSECTOR_KEY_CONTROL,
2041  		.offset = offsetof(struct flow_keys, control),
2042  	},
2043  	{
2044  		.key_id = FLOW_DISSECTOR_KEY_BASIC,
2045  		.offset = offsetof(struct flow_keys, basic),
2046  	},
2047  	{
2048  		.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
2049  		.offset = offsetof(struct flow_keys, addrs.v4addrs),
2050  	},
2051  	{
2052  		.key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
2053  		.offset = offsetof(struct flow_keys, addrs.v6addrs),
2054  	},
2055  	{
2056  		.key_id = FLOW_DISSECTOR_KEY_PORTS,
2057  		.offset = offsetof(struct flow_keys, ports),
2058  	},
2059  };
2060  
2061  static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = {
2062  	{
2063  		.key_id = FLOW_DISSECTOR_KEY_CONTROL,
2064  		.offset = offsetof(struct flow_keys, control),
2065  	},
2066  	{
2067  		.key_id = FLOW_DISSECTOR_KEY_BASIC,
2068  		.offset = offsetof(struct flow_keys, basic),
2069  	},
2070  };
2071  
2072  struct flow_dissector flow_keys_dissector __read_mostly;
2073  EXPORT_SYMBOL(flow_keys_dissector);
2074  
2075  struct flow_dissector flow_keys_basic_dissector __read_mostly;
2076  EXPORT_SYMBOL(flow_keys_basic_dissector);
2077  
init_default_flow_dissectors(void)2078  static int __init init_default_flow_dissectors(void)
2079  {
2080  	skb_flow_dissector_init(&flow_keys_dissector,
2081  				flow_keys_dissector_keys,
2082  				ARRAY_SIZE(flow_keys_dissector_keys));
2083  	skb_flow_dissector_init(&flow_keys_dissector_symmetric,
2084  				flow_keys_dissector_symmetric_keys,
2085  				ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
2086  	skb_flow_dissector_init(&flow_keys_basic_dissector,
2087  				flow_keys_basic_dissector_keys,
2088  				ARRAY_SIZE(flow_keys_basic_dissector_keys));
2089  	return 0;
2090  }
2091  core_initcall(init_default_flow_dissectors);
2092