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TOMOYO Linux Cross Reference
Linux/include/net/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, <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 list_head *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 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
178                                   netdev_features_t features);
179 
180 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
181 {
182         struct udphdr *uh;
183         unsigned int hlen, off;
184 
185         off  = skb_gro_offset(skb);
186         hlen = off + sizeof(*uh);
187         uh   = skb_gro_header_fast(skb, off);
188         if (skb_gro_header_hard(skb, hlen))
189                 uh = skb_gro_header_slow(skb, hlen, off);
190 
191         return uh;
192 }
193 
194 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
195 static inline int udp_lib_hash(struct sock *sk)
196 {
197         BUG();
198         return 0;
199 }
200 
201 void udp_lib_unhash(struct sock *sk);
202 void udp_lib_rehash(struct sock *sk, u16 new_hash);
203 
204 static inline void udp_lib_close(struct sock *sk, long timeout)
205 {
206         sk_common_release(sk);
207 }
208 
209 int udp_lib_get_port(struct sock *sk, unsigned short snum,
210                      unsigned int hash2_nulladdr);
211 
212 u32 udp_flow_hashrnd(void);
213 
214 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
215                                        int min, int max, bool use_eth)
216 {
217         u32 hash;
218 
219         if (min >= max) {
220                 /* Use default range */
221                 inet_get_local_port_range(net, &min, &max);
222         }
223 
224         hash = skb_get_hash(skb);
225         if (unlikely(!hash)) {
226                 if (use_eth) {
227                         /* Can't find a normal hash, caller has indicated an
228                          * Ethernet packet so use that to compute a hash.
229                          */
230                         hash = jhash(skb->data, 2 * ETH_ALEN,
231                                      (__force u32) skb->protocol);
232                 } else {
233                         /* Can't derive any sort of hash for the packet, set
234                          * to some consistent random value.
235                          */
236                         hash = udp_flow_hashrnd();
237                 }
238         }
239 
240         /* Since this is being sent on the wire obfuscate hash a bit
241          * to minimize possbility that any useful information to an
242          * attacker is leaked. Only upper 16 bits are relevant in the
243          * computation for 16 bit port value.
244          */
245         hash ^= hash << 16;
246 
247         return htons((((u64) hash * (max - min)) >> 32) + min);
248 }
249 
250 static inline int udp_rqueue_get(struct sock *sk)
251 {
252         return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
253 }
254 
255 /* net/ipv4/udp.c */
256 void udp_destruct_sock(struct sock *sk);
257 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
258 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
259 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
260 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
261                                int noblock, int *peeked, int *off, int *err);
262 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
263                                            int noblock, int *err)
264 {
265         int peeked, off = 0;
266 
267         return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
268 }
269 
270 int udp_v4_early_demux(struct sk_buff *skb);
271 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
272 int udp_get_port(struct sock *sk, unsigned short snum,
273                  int (*saddr_cmp)(const struct sock *,
274                                   const struct sock *));
275 void udp_err(struct sk_buff *, u32);
276 int udp_abort(struct sock *sk, int err);
277 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
278 int udp_push_pending_frames(struct sock *sk);
279 void udp_flush_pending_frames(struct sock *sk);
280 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
281 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
282 int udp_rcv(struct sk_buff *skb);
283 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
284 int udp_init_sock(struct sock *sk);
285 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
286 int __udp_disconnect(struct sock *sk, int flags);
287 int udp_disconnect(struct sock *sk, int flags);
288 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
289 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
290                                        netdev_features_t features,
291                                        bool is_ipv6);
292 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
293                        char __user *optval, int __user *optlen);
294 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
295                        char __user *optval, unsigned int optlen,
296                        int (*push_pending_frames)(struct sock *));
297 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
298                              __be32 daddr, __be16 dport, int dif);
299 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
300                                __be32 daddr, __be16 dport, int dif, int sdif,
301                                struct udp_table *tbl, struct sk_buff *skb);
302 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
303                                  __be16 sport, __be16 dport);
304 struct sock *udp6_lib_lookup(struct net *net,
305                              const struct in6_addr *saddr, __be16 sport,
306                              const struct in6_addr *daddr, __be16 dport,
307                              int dif);
308 struct sock *__udp6_lib_lookup(struct net *net,
309                                const struct in6_addr *saddr, __be16 sport,
310                                const struct in6_addr *daddr, __be16 dport,
311                                int dif, int sdif, struct udp_table *tbl,
312                                struct sk_buff *skb);
313 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
314                                  __be16 sport, __be16 dport);
315 
316 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
317  * possibly multiple cache miss on dequeue()
318  */
319 struct udp_dev_scratch {
320         /* skb->truesize and the stateless bit are embedded in a single field;
321          * do not use a bitfield since the compiler emits better/smaller code
322          * this way
323          */
324         u32 _tsize_state;
325 
326 #if BITS_PER_LONG == 64
327         /* len and the bit needed to compute skb_csum_unnecessary
328          * will be on cold cache lines at recvmsg time.
329          * skb->len can be stored on 16 bits since the udp header has been
330          * already validated and pulled.
331          */
332         u16 len;
333         bool is_linear;
334         bool csum_unnecessary;
335 #endif
336 };
337 
338 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
339 {
340         return (struct udp_dev_scratch *)&skb->dev_scratch;
341 }
342 
343 #if BITS_PER_LONG == 64
344 static inline unsigned int udp_skb_len(struct sk_buff *skb)
345 {
346         return udp_skb_scratch(skb)->len;
347 }
348 
349 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
350 {
351         return udp_skb_scratch(skb)->csum_unnecessary;
352 }
353 
354 static inline bool udp_skb_is_linear(struct sk_buff *skb)
355 {
356         return udp_skb_scratch(skb)->is_linear;
357 }
358 
359 #else
360 static inline unsigned int udp_skb_len(struct sk_buff *skb)
361 {
362         return skb->len;
363 }
364 
365 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
366 {
367         return skb_csum_unnecessary(skb);
368 }
369 
370 static inline bool udp_skb_is_linear(struct sk_buff *skb)
371 {
372         return !skb_is_nonlinear(skb);
373 }
374 #endif
375 
376 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
377                                   struct iov_iter *to)
378 {
379         int n;
380 
381         n = copy_to_iter(skb->data + off, len, to);
382         if (n == len)
383                 return 0;
384 
385         iov_iter_revert(to, n);
386         return -EFAULT;
387 }
388 
389 /*
390  *      SNMP statistics for UDP and UDP-Lite
391  */
392 #define UDP_INC_STATS(net, field, is_udplite)                 do { \
393         if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
394         else            SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
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 
399 #define __UDP6_INC_STATS(net, field, is_udplite)            do { \
400         if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
401         else            __SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
402 } while(0)
403 #define UDP6_INC_STATS(net, field, __lite)                  do { \
404         if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
405         else        SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
406 } while(0)
407 
408 #if IS_ENABLED(CONFIG_IPV6)
409 #define __UDPX_INC_STATS(sk, field)                                     \
410 do {                                                                    \
411         if ((sk)->sk_family == AF_INET)                                 \
412                 __UDP_INC_STATS(sock_net(sk), field, 0);                \
413         else                                                            \
414                 __UDP6_INC_STATS(sock_net(sk), field, 0);               \
415 } while (0)
416 #else
417 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
418 #endif
419 
420 #ifdef CONFIG_PROC_FS
421 struct udp_seq_afinfo {
422         sa_family_t                     family;
423         struct udp_table                *udp_table;
424 };
425 
426 struct udp_iter_state {
427         struct seq_net_private  p;
428         int                     bucket;
429 };
430 
431 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
432 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
433 void udp_seq_stop(struct seq_file *seq, void *v);
434 
435 extern const struct seq_operations udp_seq_ops;
436 extern const struct seq_operations udp6_seq_ops;
437 
438 int udp4_proc_init(void);
439 void udp4_proc_exit(void);
440 #endif /* CONFIG_PROC_FS */
441 
442 int udpv4_offload_init(void);
443 
444 void udp_init(void);
445 
446 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
447 void udp_encap_enable(void);
448 #if IS_ENABLED(CONFIG_IPV6)
449 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
450 void udpv6_encap_enable(void);
451 #endif
452 
453 #endif  /* _UDP_H */
454 

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