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udp.h
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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, <[email protected]>
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 
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 
61 struct udp_hslot {
62  struct hlist_nulls_head head;
63  int count;
64  spinlock_t lock;
65 } __attribute__((aligned(2 * sizeof(long))));
66 
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 extern 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 /* Note: this must match 'valbool' in sock_setsockopt */
99 #define UDP_CSUM_NOXMIT 1
100 
101 /* Used by SunRPC/xprt layer. */
102 #define UDP_CSUM_NORCV 2
103 
104 /* Default, as per the RFC, is to always do csums. */
105 #define UDP_CSUM_DEFAULT 0
106 
107 extern struct proto udp_prot;
108 
109 extern atomic_long_t udp_memory_allocated;
110 
111 /* sysctl variables for udp */
112 extern long sysctl_udp_mem[3];
113 extern int sysctl_udp_rmem_min;
114 extern int sysctl_udp_wmem_min;
115 
116 struct sk_buff;
117 
118 /*
119  * Generic checksumming routines for UDP(-Lite) v4 and v6
120  */
121 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
122 {
123  return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov);
124 }
125 
126 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
127 {
128  return !skb_csum_unnecessary(skb) &&
129  __udp_lib_checksum_complete(skb);
130 }
131 
138 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
139 {
140  __wsum csum = csum_partial(skb_transport_header(skb),
141  sizeof(struct udphdr), 0);
142  skb_queue_walk(&sk->sk_write_queue, skb) {
143  csum = csum_add(csum, skb->csum);
144  }
145  return csum;
146 }
147 
148 static inline __wsum udp_csum(struct sk_buff *skb)
149 {
150  __wsum csum = csum_partial(skb_transport_header(skb),
151  sizeof(struct udphdr), skb->csum);
152 
153  for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
154  csum = csum_add(csum, skb->csum);
155  }
156  return csum;
157 }
158 
159 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
160 static inline void udp_lib_hash(struct sock *sk)
161 {
162  BUG();
163 }
164 
165 extern void udp_lib_unhash(struct sock *sk);
166 extern void udp_lib_rehash(struct sock *sk, u16 new_hash);
167 
168 static inline void udp_lib_close(struct sock *sk, long timeout)
169 {
170  sk_common_release(sk);
171 }
172 
173 extern int udp_lib_get_port(struct sock *sk, unsigned short snum,
174  int (*)(const struct sock *,const struct sock *),
175  unsigned int hash2_nulladdr);
176 
177 /* net/ipv4/udp.c */
178 extern int udp_get_port(struct sock *sk, unsigned short snum,
179  int (*saddr_cmp)(const struct sock *,
180  const struct sock *));
181 extern void udp_err(struct sk_buff *, u32);
182 extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
183  struct msghdr *msg, size_t len);
184 extern void udp_flush_pending_frames(struct sock *sk);
185 extern int udp_rcv(struct sk_buff *skb);
186 extern int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
187 extern int udp_disconnect(struct sock *sk, int flags);
188 extern unsigned int udp_poll(struct file *file, struct socket *sock,
189  poll_table *wait);
190 extern int udp_lib_getsockopt(struct sock *sk, int level, int optname,
191  char __user *optval, int __user *optlen);
192 extern int udp_lib_setsockopt(struct sock *sk, int level, int optname,
193  char __user *optval, unsigned int optlen,
194  int (*push_pending_frames)(struct sock *));
195 extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
196  __be32 daddr, __be16 dport,
197  int dif);
198 extern struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
199  __be32 daddr, __be16 dport,
200  int dif, struct udp_table *tbl);
201 extern struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
202  const struct in6_addr *daddr, __be16 dport,
203  int dif);
204 extern struct sock *__udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
205  const struct in6_addr *daddr, __be16 dport,
206  int dif, struct udp_table *tbl);
207 
208 /*
209  * SNMP statistics for UDP and UDP-Lite
210  */
211 #define UDP_INC_STATS_USER(net, field, is_udplite) do { \
212  if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field); \
213  else SNMP_INC_STATS_USER((net)->mib.udp_statistics, field); } while(0)
214 #define UDP_INC_STATS_BH(net, field, is_udplite) do { \
215  if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field); \
216  else SNMP_INC_STATS_BH((net)->mib.udp_statistics, field); } while(0)
217 
218 #define UDP6_INC_STATS_BH(net, field, is_udplite) do { \
219  if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
220  else SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field); \
221 } while(0)
222 #define UDP6_INC_STATS_USER(net, field, __lite) do { \
223  if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field); \
224  else SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field); \
225 } while(0)
226 
227 #if IS_ENABLED(CONFIG_IPV6)
228 #define UDPX_INC_STATS_BH(sk, field) \
229  do { \
230  if ((sk)->sk_family == AF_INET) \
231  UDP_INC_STATS_BH(sock_net(sk), field, 0); \
232  else \
233  UDP6_INC_STATS_BH(sock_net(sk), field, 0); \
234  } while (0);
235 #else
236 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
237 #endif
238 
239 /* /proc */
240 int udp_seq_open(struct inode *inode, struct file *file);
241 
242 struct udp_seq_afinfo {
243  char *name;
244  sa_family_t family;
245  struct udp_table *udp_table;
246  const struct file_operations *seq_fops;
247  struct seq_operations seq_ops;
248 };
249 
250 struct udp_iter_state {
251  struct seq_net_private p;
252  sa_family_t family;
253  int bucket;
254  struct udp_table *udp_table;
255 };
256 
257 #ifdef CONFIG_PROC_FS
258 extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
259 extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
260 
261 extern int udp4_proc_init(void);
262 extern void udp4_proc_exit(void);
263 #endif
264 
265 extern void udp_init(void);
266 
267 extern int udp4_ufo_send_check(struct sk_buff *skb);
268 extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
269  netdev_features_t features);
270 extern void udp_encap_enable(void);
271 #if IS_ENABLED(CONFIG_IPV6)
272 extern void udpv6_encap_enable(void);
273 #endif
274 #endif /* _UDP_H */
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