xref: /linux/include/net/udp.h (revision 10accd2e6890b57db8e717e9aee91b791f90fe14)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for the UDP module.
7  *
8  * Version:	@(#)udp.h	1.0.2	05/07/93
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *
13  * Fixes:
14  *		Alan Cox	: Turned on udp checksums. I don't want to
15  *				  chase 'memory corruption' bugs that aren't!
16  *
17  *		This program is free software; you can redistribute it and/or
18  *		modify it under the terms of the GNU General Public License
19  *		as published by the Free Software Foundation; either version
20  *		2 of the License, or (at your option) any later version.
21  */
22 #ifndef _UDP_H
23 #define _UDP_H
24 
25 #include <linux/list.h>
26 #include <linux/bug.h>
27 #include <net/inet_sock.h>
28 #include <net/sock.h>
29 #include <net/snmp.h>
30 #include <net/ip.h>
31 #include <linux/ipv6.h>
32 #include <linux/seq_file.h>
33 #include <linux/poll.h>
34 
35 /**
36  *	struct udp_skb_cb  -  UDP(-Lite) private variables
37  *
38  *	@header:      private variables used by IPv4/IPv6
39  *	@cscov:       checksum coverage length (UDP-Lite only)
40  *	@partial_cov: if set indicates partial csum coverage
41  */
42 struct udp_skb_cb {
43 	union {
44 		struct inet_skb_parm	h4;
45 #if IS_ENABLED(CONFIG_IPV6)
46 		struct inet6_skb_parm	h6;
47 #endif
48 	} header;
49 	__u16		cscov;
50 	__u8		partial_cov;
51 };
52 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
53 
54 /**
55  *	struct udp_hslot - UDP hash slot
56  *
57  *	@head:	head of list of sockets
58  *	@count:	number of sockets in 'head' list
59  *	@lock:	spinlock protecting changes to head/count
60  */
61 struct udp_hslot {
62 	struct hlist_head	head;
63 	int			count;
64 	spinlock_t		lock;
65 } __attribute__((aligned(2 * sizeof(long))));
66 
67 /**
68  *	struct udp_table - UDP table
69  *
70  *	@hash:	hash table, sockets are hashed on (local port)
71  *	@hash2:	hash table, sockets are hashed on (local port, local address)
72  *	@mask:	number of slots in hash tables, minus 1
73  *	@log:	log2(number of slots in hash table)
74  */
75 struct udp_table {
76 	struct udp_hslot	*hash;
77 	struct udp_hslot	*hash2;
78 	unsigned int		mask;
79 	unsigned int		log;
80 };
81 extern struct udp_table udp_table;
82 void udp_table_init(struct udp_table *, const char *);
83 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
84 					     struct net *net, unsigned int num)
85 {
86 	return &table->hash[udp_hashfn(net, num, table->mask)];
87 }
88 /*
89  * For secondary hash, net_hash_mix() is performed before calling
90  * udp_hashslot2(), this explains difference with udp_hashslot()
91  */
92 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
93 					      unsigned int hash)
94 {
95 	return &table->hash2[hash & table->mask];
96 }
97 
98 extern struct proto udp_prot;
99 
100 extern atomic_long_t udp_memory_allocated;
101 
102 /* sysctl variables for udp */
103 extern long sysctl_udp_mem[3];
104 extern int sysctl_udp_rmem_min;
105 extern int sysctl_udp_wmem_min;
106 
107 struct sk_buff;
108 
109 /*
110  *	Generic checksumming routines for UDP(-Lite) v4 and v6
111  */
112 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
113 {
114 	return (UDP_SKB_CB(skb)->cscov == skb->len ?
115 		__skb_checksum_complete(skb) :
116 		__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
117 }
118 
119 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
120 {
121 	return !skb_csum_unnecessary(skb) &&
122 		__udp_lib_checksum_complete(skb);
123 }
124 
125 /**
126  * 	udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
127  * 	@sk: 	socket we are writing to
128  * 	@skb: 	sk_buff containing the filled-in UDP header
129  * 	        (checksum field must be zeroed out)
130  */
131 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
132 {
133 	__wsum csum = csum_partial(skb_transport_header(skb),
134 				   sizeof(struct udphdr), 0);
135 	skb_queue_walk(&sk->sk_write_queue, skb) {
136 		csum = csum_add(csum, skb->csum);
137 	}
138 	return csum;
139 }
140 
141 static inline __wsum udp_csum(struct sk_buff *skb)
142 {
143 	__wsum csum = csum_partial(skb_transport_header(skb),
144 				   sizeof(struct udphdr), skb->csum);
145 
146 	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
147 		csum = csum_add(csum, skb->csum);
148 	}
149 	return csum;
150 }
151 
152 static inline __sum16 udp_v4_check(int len, __be32 saddr,
153 				   __be32 daddr, __wsum base)
154 {
155 	return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
156 }
157 
158 void udp_set_csum(bool nocheck, struct sk_buff *skb,
159 		  __be32 saddr, __be32 daddr, int len);
160 
161 static inline void udp_csum_pull_header(struct sk_buff *skb)
162 {
163 	if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
164 		skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
165 					 skb->csum);
166 	skb_pull_rcsum(skb, sizeof(struct udphdr));
167 	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
168 }
169 
170 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
171 				     __be16 dport);
172 
173 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
174 				 struct udphdr *uh, udp_lookup_t lookup);
175 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
176 
177 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
178 {
179 	struct udphdr *uh;
180 	unsigned int hlen, off;
181 
182 	off  = skb_gro_offset(skb);
183 	hlen = off + sizeof(*uh);
184 	uh   = skb_gro_header_fast(skb, off);
185 	if (skb_gro_header_hard(skb, hlen))
186 		uh = skb_gro_header_slow(skb, hlen, off);
187 
188 	return uh;
189 }
190 
191 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
192 static inline int udp_lib_hash(struct sock *sk)
193 {
194 	BUG();
195 	return 0;
196 }
197 
198 void udp_lib_unhash(struct sock *sk);
199 void udp_lib_rehash(struct sock *sk, u16 new_hash);
200 
201 static inline void udp_lib_close(struct sock *sk, long timeout)
202 {
203 	sk_common_release(sk);
204 }
205 
206 int udp_lib_get_port(struct sock *sk, unsigned short snum,
207 		     int (*)(const struct sock *, const struct sock *, bool),
208 		     unsigned int hash2_nulladdr);
209 
210 u32 udp_flow_hashrnd(void);
211 
212 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
213 				       int min, int max, bool use_eth)
214 {
215 	u32 hash;
216 
217 	if (min >= max) {
218 		/* Use default range */
219 		inet_get_local_port_range(net, &min, &max);
220 	}
221 
222 	hash = skb_get_hash(skb);
223 	if (unlikely(!hash)) {
224 		if (use_eth) {
225 			/* Can't find a normal hash, caller has indicated an
226 			 * Ethernet packet so use that to compute a hash.
227 			 */
228 			hash = jhash(skb->data, 2 * ETH_ALEN,
229 				     (__force u32) skb->protocol);
230 		} else {
231 			/* Can't derive any sort of hash for the packet, set
232 			 * to some consistent random value.
233 			 */
234 			hash = udp_flow_hashrnd();
235 		}
236 	}
237 
238 	/* Since this is being sent on the wire obfuscate hash a bit
239 	 * to minimize possbility that any useful information to an
240 	 * attacker is leaked. Only upper 16 bits are relevant in the
241 	 * computation for 16 bit port value.
242 	 */
243 	hash ^= hash << 16;
244 
245 	return htons((((u64) hash * (max - min)) >> 32) + min);
246 }
247 
248 /* net/ipv4/udp.c */
249 void udp_v4_early_demux(struct sk_buff *skb);
250 int udp_get_port(struct sock *sk, unsigned short snum,
251 		 int (*saddr_cmp)(const struct sock *,
252 				  const struct sock *));
253 void udp_err(struct sk_buff *, u32);
254 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
255 int udp_push_pending_frames(struct sock *sk);
256 void udp_flush_pending_frames(struct sock *sk);
257 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
258 int udp_rcv(struct sk_buff *skb);
259 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
260 int udp_disconnect(struct sock *sk, int flags);
261 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait);
262 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
263 				       netdev_features_t features,
264 				       bool is_ipv6);
265 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
266 		       char __user *optval, int __user *optlen);
267 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
268 		       char __user *optval, unsigned int optlen,
269 		       int (*push_pending_frames)(struct sock *));
270 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
271 			     __be32 daddr, __be16 dport, int dif);
272 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
273 			       __be32 daddr, __be16 dport, int dif,
274 			       struct udp_table *tbl, struct sk_buff *skb);
275 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
276 				 __be16 sport, __be16 dport);
277 struct sock *udp6_lib_lookup(struct net *net,
278 			     const struct in6_addr *saddr, __be16 sport,
279 			     const struct in6_addr *daddr, __be16 dport,
280 			     int dif);
281 struct sock *__udp6_lib_lookup(struct net *net,
282 			       const struct in6_addr *saddr, __be16 sport,
283 			       const struct in6_addr *daddr, __be16 dport,
284 			       int dif, struct udp_table *tbl,
285 			       struct sk_buff *skb);
286 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
287 				 __be16 sport, __be16 dport);
288 
289 /*
290  * 	SNMP statistics for UDP and UDP-Lite
291  */
292 #define UDP_INC_STATS(net, field, is_udplite)		      do { \
293 	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
294 	else		SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
295 #define __UDP_INC_STATS(net, field, is_udplite) 	      do { \
296 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
297 	else		__SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)
298 
299 #define __UDP6_INC_STATS(net, field, is_udplite)	    do { \
300 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
301 	else		__SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
302 } while(0)
303 #define UDP6_INC_STATS(net, field, __lite)		    do { \
304 	if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
305 	else	    SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
306 } while(0)
307 
308 #if IS_ENABLED(CONFIG_IPV6)
309 #define __UDPX_INC_STATS(sk, field)					\
310 do {									\
311 	if ((sk)->sk_family == AF_INET)					\
312 		__UDP_INC_STATS(sock_net(sk), field, 0);		\
313 	else								\
314 		__UDP6_INC_STATS(sock_net(sk), field, 0);		\
315 } while (0)
316 #else
317 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
318 #endif
319 
320 /* /proc */
321 int udp_seq_open(struct inode *inode, struct file *file);
322 
323 struct udp_seq_afinfo {
324 	char				*name;
325 	sa_family_t			family;
326 	struct udp_table		*udp_table;
327 	const struct file_operations	*seq_fops;
328 	struct seq_operations		seq_ops;
329 };
330 
331 struct udp_iter_state {
332 	struct seq_net_private  p;
333 	sa_family_t		family;
334 	int			bucket;
335 	struct udp_table	*udp_table;
336 };
337 
338 #ifdef CONFIG_PROC_FS
339 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
340 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
341 
342 int udp4_proc_init(void);
343 void udp4_proc_exit(void);
344 #endif
345 
346 int udpv4_offload_init(void);
347 
348 void udp_init(void);
349 
350 void udp_encap_enable(void);
351 #if IS_ENABLED(CONFIG_IPV6)
352 void udpv6_encap_enable(void);
353 #endif
354 #endif	/* _UDP_H */
355