include/net/udp.h

   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_nulls_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 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
 132 /**
 133  *      udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
 134  *      @sk:    socket we are writing to
 135  *      @skb:   sk_buff containing the filled-in UDP header
 136  *              (checksum field must be zeroed out)
 137  */
 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 */