xref: /openbmc/linux/include/net/udp.h (revision cc97777c)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
4  *		operating system.  INET is implemented using the  BSD Socket
5  *		interface as the means of communication with the user level.
6  *
7  *		Definitions for the UDP module.
8  *
9  * Version:	@(#)udp.h	1.0.2	05/07/93
10  *
11  * Authors:	Ross Biro
12  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13  *
14  * Fixes:
15  *		Alan Cox	: Turned on udp checksums. I don't want to
16  *				  chase 'memory corruption' bugs that aren't!
17  */
18 #ifndef _UDP_H
19 #define _UDP_H
20 
21 #include <linux/list.h>
22 #include <linux/bug.h>
23 #include <net/inet_sock.h>
24 #include <net/gso.h>
25 #include <net/sock.h>
26 #include <net/snmp.h>
27 #include <net/ip.h>
28 #include <linux/ipv6.h>
29 #include <linux/seq_file.h>
30 #include <linux/poll.h>
31 #include <linux/indirect_call_wrapper.h>
32 
33 /**
34  *	struct udp_skb_cb  -  UDP(-Lite) private variables
35  *
36  *	@header:      private variables used by IPv4/IPv6
37  *	@cscov:       checksum coverage length (UDP-Lite only)
38  *	@partial_cov: if set indicates partial csum coverage
39  */
40 struct udp_skb_cb {
41 	union {
42 		struct inet_skb_parm	h4;
43 #if IS_ENABLED(CONFIG_IPV6)
44 		struct inet6_skb_parm	h6;
45 #endif
46 	} header;
47 	__u16		cscov;
48 	__u8		partial_cov;
49 };
50 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
51 
52 /**
53  *	struct udp_hslot - UDP hash slot
54  *
55  *	@head:	head of list of sockets
56  *	@count:	number of sockets in 'head' list
57  *	@lock:	spinlock protecting changes to head/count
58  */
59 struct udp_hslot {
60 	struct hlist_head	head;
61 	int			count;
62 	spinlock_t		lock;
63 } __attribute__((aligned(2 * sizeof(long))));
64 
65 /**
66  *	struct udp_table - UDP table
67  *
68  *	@hash:	hash table, sockets are hashed on (local port)
69  *	@hash2:	hash table, sockets are hashed on (local port, local address)
70  *	@mask:	number of slots in hash tables, minus 1
71  *	@log:	log2(number of slots in hash table)
72  */
73 struct udp_table {
74 	struct udp_hslot	*hash;
75 	struct udp_hslot	*hash2;
76 	unsigned int		mask;
77 	unsigned int		log;
78 };
79 extern struct udp_table udp_table;
80 void udp_table_init(struct udp_table *, const char *);
udp_hashslot(struct udp_table * table,struct net * net,unsigned int num)81 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
82 					     struct net *net, unsigned int num)
83 {
84 	return &table->hash[udp_hashfn(net, num, table->mask)];
85 }
86 /*
87  * For secondary hash, net_hash_mix() is performed before calling
88  * udp_hashslot2(), this explains difference with udp_hashslot()
89  */
udp_hashslot2(struct udp_table * table,unsigned int hash)90 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
91 					      unsigned int hash)
92 {
93 	return &table->hash2[hash & table->mask];
94 }
95 
96 extern struct proto udp_prot;
97 
98 extern atomic_long_t udp_memory_allocated;
99 DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
100 
101 /* sysctl variables for udp */
102 extern long sysctl_udp_mem[3];
103 extern int sysctl_udp_rmem_min;
104 extern int sysctl_udp_wmem_min;
105 
106 struct sk_buff;
107 
108 /*
109  *	Generic checksumming routines for UDP(-Lite) v4 and v6
110  */
__udp_lib_checksum_complete(struct sk_buff * skb)111 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
112 {
113 	return (UDP_SKB_CB(skb)->cscov == skb->len ?
114 		__skb_checksum_complete(skb) :
115 		__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
116 }
117 
udp_lib_checksum_complete(struct sk_buff * skb)118 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
119 {
120 	return !skb_csum_unnecessary(skb) &&
121 		__udp_lib_checksum_complete(skb);
122 }
123 
124 /**
125  * 	udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
126  * 	@sk: 	socket we are writing to
127  * 	@skb: 	sk_buff containing the filled-in UDP header
128  * 	        (checksum field must be zeroed out)
129  */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)130 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
131 {
132 	__wsum csum = csum_partial(skb_transport_header(skb),
133 				   sizeof(struct udphdr), 0);
134 	skb_queue_walk(&sk->sk_write_queue, skb) {
135 		csum = csum_add(csum, skb->csum);
136 	}
137 	return csum;
138 }
139 
udp_csum(struct sk_buff * skb)140 static inline __wsum udp_csum(struct sk_buff *skb)
141 {
142 	__wsum csum = csum_partial(skb_transport_header(skb),
143 				   sizeof(struct udphdr), skb->csum);
144 
145 	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
146 		csum = csum_add(csum, skb->csum);
147 	}
148 	return csum;
149 }
150 
udp_v4_check(int len,__be32 saddr,__be32 daddr,__wsum base)151 static inline __sum16 udp_v4_check(int len, __be32 saddr,
152 				   __be32 daddr, __wsum base)
153 {
154 	return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
155 }
156 
157 void udp_set_csum(bool nocheck, struct sk_buff *skb,
158 		  __be32 saddr, __be32 daddr, int len);
159 
udp_csum_pull_header(struct sk_buff * skb)160 static inline void udp_csum_pull_header(struct sk_buff *skb)
161 {
162 	if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
163 		skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
164 					 skb->csum);
165 	skb_pull_rcsum(skb, sizeof(struct udphdr));
166 	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
167 }
168 
169 typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
170 				     __be16 dport);
171 
172 void udp_v6_early_demux(struct sk_buff *skb);
173 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
174 
175 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
176 				  netdev_features_t features, bool is_ipv6);
177 
udp_lib_init_sock(struct sock * sk)178 static inline void udp_lib_init_sock(struct sock *sk)
179 {
180 	struct udp_sock *up = udp_sk(sk);
181 
182 	skb_queue_head_init(&up->reader_queue);
183 	up->forward_threshold = sk->sk_rcvbuf >> 2;
184 	set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
185 }
186 
187 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)188 static inline int udp_lib_hash(struct sock *sk)
189 {
190 	BUG();
191 	return 0;
192 }
193 
194 void udp_lib_unhash(struct sock *sk);
195 void udp_lib_rehash(struct sock *sk, u16 new_hash);
196 
udp_lib_close(struct sock * sk,long timeout)197 static inline void udp_lib_close(struct sock *sk, long timeout)
198 {
199 	sk_common_release(sk);
200 }
201 
202 int udp_lib_get_port(struct sock *sk, unsigned short snum,
203 		     unsigned int hash2_nulladdr);
204 
205 u32 udp_flow_hashrnd(void);
206 
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)207 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
208 				       int min, int max, bool use_eth)
209 {
210 	u32 hash;
211 
212 	if (min >= max) {
213 		/* Use default range */
214 		inet_get_local_port_range(net, &min, &max);
215 	}
216 
217 	hash = skb_get_hash(skb);
218 	if (unlikely(!hash)) {
219 		if (use_eth) {
220 			/* Can't find a normal hash, caller has indicated an
221 			 * Ethernet packet so use that to compute a hash.
222 			 */
223 			hash = jhash(skb->data, 2 * ETH_ALEN,
224 				     (__force u32) skb->protocol);
225 		} else {
226 			/* Can't derive any sort of hash for the packet, set
227 			 * to some consistent random value.
228 			 */
229 			hash = udp_flow_hashrnd();
230 		}
231 	}
232 
233 	/* Since this is being sent on the wire obfuscate hash a bit
234 	 * to minimize possbility that any useful information to an
235 	 * attacker is leaked. Only upper 16 bits are relevant in the
236 	 * computation for 16 bit port value.
237 	 */
238 	hash ^= hash << 16;
239 
240 	return htons((((u64) hash * (max - min)) >> 32) + min);
241 }
242 
udp_rqueue_get(struct sock * sk)243 static inline int udp_rqueue_get(struct sock *sk)
244 {
245 	return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
246 }
247 
udp_sk_bound_dev_eq(struct net * net,int bound_dev_if,int dif,int sdif)248 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
249 				       int dif, int sdif)
250 {
251 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
252 	return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
253 				 bound_dev_if, dif, sdif);
254 #else
255 	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
256 #endif
257 }
258 
259 /* net/ipv4/udp.c */
260 void udp_destruct_common(struct sock *sk);
261 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
262 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
263 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
264 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
265 			       int *err);
skb_recv_udp(struct sock * sk,unsigned int flags,int * err)266 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
267 					   int *err)
268 {
269 	int off = 0;
270 
271 	return __skb_recv_udp(sk, flags, &off, err);
272 }
273 
274 int udp_v4_early_demux(struct sk_buff *skb);
275 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
276 int udp_err(struct sk_buff *, u32);
277 int udp_abort(struct sock *sk, int err);
278 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
279 void udp_splice_eof(struct socket *sock);
280 int udp_push_pending_frames(struct sock *sk);
281 void udp_flush_pending_frames(struct sock *sk);
282 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
283 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
284 int udp_rcv(struct sk_buff *skb);
285 int udp_ioctl(struct sock *sk, int cmd, int *karg);
286 int udp_init_sock(struct sock *sk);
287 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
288 int __udp_disconnect(struct sock *sk, int flags);
289 int udp_disconnect(struct sock *sk, int flags);
290 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
291 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
292 				       netdev_features_t features,
293 				       bool is_ipv6);
294 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
295 		       char __user *optval, int __user *optlen);
296 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
297 		       sockptr_t optval, unsigned int optlen,
298 		       int (*push_pending_frames)(struct sock *));
299 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
300 			     __be32 daddr, __be16 dport, int dif);
301 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
302 			       __be32 daddr, __be16 dport, int dif, int sdif,
303 			       struct udp_table *tbl, struct sk_buff *skb);
304 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
305 				 __be16 sport, __be16 dport);
306 struct sock *udp6_lib_lookup(struct net *net,
307 			     const struct in6_addr *saddr, __be16 sport,
308 			     const struct in6_addr *daddr, __be16 dport,
309 			     int dif);
310 struct sock *__udp6_lib_lookup(struct net *net,
311 			       const struct in6_addr *saddr, __be16 sport,
312 			       const struct in6_addr *daddr, __be16 dport,
313 			       int dif, int sdif, struct udp_table *tbl,
314 			       struct sk_buff *skb);
315 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
316 				 __be16 sport, __be16 dport);
317 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
318 
319 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
320  * possibly multiple cache miss on dequeue()
321  */
322 struct udp_dev_scratch {
323 	/* skb->truesize and the stateless bit are embedded in a single field;
324 	 * do not use a bitfield since the compiler emits better/smaller code
325 	 * this way
326 	 */
327 	u32 _tsize_state;
328 
329 #if BITS_PER_LONG == 64
330 	/* len and the bit needed to compute skb_csum_unnecessary
331 	 * will be on cold cache lines at recvmsg time.
332 	 * skb->len can be stored on 16 bits since the udp header has been
333 	 * already validated and pulled.
334 	 */
335 	u16 len;
336 	bool is_linear;
337 	bool csum_unnecessary;
338 #endif
339 };
340 
udp_skb_scratch(struct sk_buff * skb)341 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
342 {
343 	return (struct udp_dev_scratch *)&skb->dev_scratch;
344 }
345 
346 #if BITS_PER_LONG == 64
udp_skb_len(struct sk_buff * skb)347 static inline unsigned int udp_skb_len(struct sk_buff *skb)
348 {
349 	return udp_skb_scratch(skb)->len;
350 }
351 
udp_skb_csum_unnecessary(struct sk_buff * skb)352 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
353 {
354 	return udp_skb_scratch(skb)->csum_unnecessary;
355 }
356 
udp_skb_is_linear(struct sk_buff * skb)357 static inline bool udp_skb_is_linear(struct sk_buff *skb)
358 {
359 	return udp_skb_scratch(skb)->is_linear;
360 }
361 
362 #else
udp_skb_len(struct sk_buff * skb)363 static inline unsigned int udp_skb_len(struct sk_buff *skb)
364 {
365 	return skb->len;
366 }
367 
udp_skb_csum_unnecessary(struct sk_buff * skb)368 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
369 {
370 	return skb_csum_unnecessary(skb);
371 }
372 
udp_skb_is_linear(struct sk_buff * skb)373 static inline bool udp_skb_is_linear(struct sk_buff *skb)
374 {
375 	return !skb_is_nonlinear(skb);
376 }
377 #endif
378 
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)379 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
380 				  struct iov_iter *to)
381 {
382 	int n;
383 
384 	n = copy_to_iter(skb->data + off, len, to);
385 	if (n == len)
386 		return 0;
387 
388 	iov_iter_revert(to, n);
389 	return -EFAULT;
390 }
391 
392 /*
393  * 	SNMP statistics for UDP and UDP-Lite
394  */
395 #define UDP_INC_STATS(net, field, is_udplite)		      do { \
396 	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
397 	else		SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
398 #define __UDP_INC_STATS(net, field, is_udplite) 	      do { \
399 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
400 	else		__SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)
401 
402 #define __UDP6_INC_STATS(net, field, is_udplite)	    do { \
403 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
404 	else		__SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
405 } while(0)
406 #define UDP6_INC_STATS(net, field, __lite)		    do { \
407 	if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
408 	else	    SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
409 } while(0)
410 
411 #if IS_ENABLED(CONFIG_IPV6)
412 #define __UDPX_MIB(sk, ipv4)						\
413 ({									\
414 	ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics :	\
415 				 sock_net(sk)->mib.udp_statistics) :	\
416 		(IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 :	\
417 				 sock_net(sk)->mib.udp_stats_in6);	\
418 })
419 #else
420 #define __UDPX_MIB(sk, ipv4)						\
421 ({									\
422 	IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics :		\
423 			 sock_net(sk)->mib.udp_statistics;		\
424 })
425 #endif
426 
427 #define __UDPX_INC_STATS(sk, field) \
428 	__SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
429 
430 #ifdef CONFIG_PROC_FS
431 struct udp_seq_afinfo {
432 	sa_family_t			family;
433 	struct udp_table		*udp_table;
434 };
435 
436 struct udp_iter_state {
437 	struct seq_net_private  p;
438 	int			bucket;
439 };
440 
441 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
442 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
443 void udp_seq_stop(struct seq_file *seq, void *v);
444 
445 extern const struct seq_operations udp_seq_ops;
446 extern const struct seq_operations udp6_seq_ops;
447 
448 int udp4_proc_init(void);
449 void udp4_proc_exit(void);
450 #endif /* CONFIG_PROC_FS */
451 
452 int udpv4_offload_init(void);
453 
454 void udp_init(void);
455 
456 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
457 void udp_encap_enable(void);
458 void udp_encap_disable(void);
459 #if IS_ENABLED(CONFIG_IPV6)
460 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
461 void udpv6_encap_enable(void);
462 #endif
463 
udp_rcv_segment(struct sock * sk,struct sk_buff * skb,bool ipv4)464 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
465 					      struct sk_buff *skb, bool ipv4)
466 {
467 	netdev_features_t features = NETIF_F_SG;
468 	struct sk_buff *segs;
469 
470 	/* Avoid csum recalculation by skb_segment unless userspace explicitly
471 	 * asks for the final checksum values
472 	 */
473 	if (!inet_get_convert_csum(sk))
474 		features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
475 
476 	/* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
477 	 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
478 	 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
479 	 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
480 	 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
481 	 * Reset in this specific case, where PARTIAL is both correct and
482 	 * required.
483 	 */
484 	if (skb->pkt_type == PACKET_LOOPBACK)
485 		skb->ip_summed = CHECKSUM_PARTIAL;
486 
487 	/* the GSO CB lays after the UDP one, no need to save and restore any
488 	 * CB fragment
489 	 */
490 	segs = __skb_gso_segment(skb, features, false);
491 	if (IS_ERR_OR_NULL(segs)) {
492 		int segs_nr = skb_shinfo(skb)->gso_segs;
493 
494 		atomic_add(segs_nr, &sk->sk_drops);
495 		SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
496 		kfree_skb(skb);
497 		return NULL;
498 	}
499 
500 	consume_skb(skb);
501 	return segs;
502 }
503 
udp_post_segment_fix_csum(struct sk_buff * skb)504 static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
505 {
506 	/* UDP-lite can't land here - no GRO */
507 	WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
508 
509 	/* UDP packets generated with UDP_SEGMENT and traversing:
510 	 *
511 	 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
512 	 *
513 	 * can reach an UDP socket with CHECKSUM_NONE, because
514 	 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
515 	 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
516 	 * have a valid checksum, as the GRO engine validates the UDP csum
517 	 * before the aggregation and nobody strips such info in between.
518 	 * Instead of adding another check in the tunnel fastpath, we can force
519 	 * a valid csum after the segmentation.
520 	 * Additionally fixup the UDP CB.
521 	 */
522 	UDP_SKB_CB(skb)->cscov = skb->len;
523 	if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
524 		skb->csum_valid = 1;
525 }
526 
527 #ifdef CONFIG_BPF_SYSCALL
528 struct sk_psock;
529 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
530 #endif
531 
532 #endif	/* _UDP_H */
533