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 <net/inet_sock.h>
  27 #include <net/sock.h>
  28 #include <net/snmp.h>
  29 #include <net/ip.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/poll.h>
  33
  34 /**
  35  *      struct udp_skb_cb  -  UDP(-Lite) private variables
  36  *
  37  *      @header:      private variables used by IPv4/IPv6
  38  *      @cscov:       checksum coverage length (UDP-Lite only)
  39  *      @partial_cov: if set indicates partial csum coverage
  40  */
  41 struct udp_skb_cb {
  42         union {
  43                 struct inet_skb_parm    h4;
  44 #if IS_ENABLED(CONFIG_IPV6)
  45                 struct inet6_skb_parm   h6;
  46 #endif
  47         } header;
  48         __u16           cscov;
  49         __u8            partial_cov;
  50 };
  51 #define UDP_SKB_CB(__skb)       ((struct udp_skb_cb *)((__skb)->cb))
  52
  53 /**
  54  *      struct udp_hslot - UDP hash slot
  55  *
  56  *      @head:  head of list of sockets
  57  *      @count: number of sockets in 'head' list
  58  *      @lock:  spinlock protecting changes to head/count
  59  */
  60 struct udp_hslot {
  61         struct hlist_nulls_head head;
  62         int                     count;
  63         spinlock_t              lock;
  64 } __attribute__((aligned(2 * sizeof(long))));
  65
  66 /**
  67  *      struct udp_table - UDP table
  68  *
  69  *      @hash:  hash table, sockets are hashed on (local port)
  70  *      @hash2: hash table, sockets are hashed on (local port, local address)
  71  *      @mask:  number of slots in hash tables, minus 1
  72  *      @log:   log2(number of slots in hash table)
  73  */
  74 struct udp_table {
  75         struct udp_hslot        *hash;
  76         struct udp_hslot        *hash2;
  77         unsigned int            mask;
  78         unsigned int            log;
  79 };
  80 extern struct udp_table udp_table;
  81 extern void udp_table_init(struct udp_table *, const char *);
  82 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
  83                                              struct net *net, unsigned num)
  84 {
  85         return &table->hash[udp_hashfn(net, num, table->mask)];
  86 }
  87 /*
  88  * For secondary hash, net_hash_mix() is performed before calling
  89  * udp_hashslot2(), this explains difference with udp_hashslot()
  90  */
  91 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
  92                                               unsigned int hash)
  93 {
  94         return &table->hash2[hash & table->mask];
  95 }
  96
  97 /* Note: this must match 'valbool' in sock_setsockopt */
  98 #define UDP_CSUM_NOXMIT         1
  99
 100 /* Used by SunRPC/xprt layer. */
 101 #define UDP_CSUM_NORCV          2
 102
 103 /* Default, as per the RFC, is to always do csums. */
 104 #define UDP_CSUM_DEFAULT        0
 105
 106 extern struct proto udp_prot;
 107
 108 extern atomic_long_t udp_memory_allocated;
 109
 110 /* sysctl variables for udp */
 111 extern long sysctl_udp_mem[3];
 112 extern int sysctl_udp_rmem_min;
 113 extern int sysctl_udp_wmem_min;
 114
 115 struct sk_buff;
 116
 117 /*
 118  *      Generic checksumming routines for UDP(-Lite) v4 and v6
 119  */
 120 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
 121 {
 122         return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov);
 123 }
 124
 125 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
 126 {
 127         return !skb_csum_unnecessary(skb) &&
 128                 __udp_lib_checksum_complete(skb);
 129 }
 130
 131 /**
 132  *      udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
 133  *      @sk:    socket we are writing to
 134  *      @skb:   sk_buff containing the filled-in UDP header
 135  *              (checksum field must be zeroed out)
 136  */
 137 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 138 {
 139         __wsum csum = csum_partial(skb_transport_header(skb),
 140                                    sizeof(struct udphdr), 0);
 141         skb_queue_walk(&sk->sk_write_queue, skb) {
 142                 csum = csum_add(csum, skb->csum);
 143         }
 144         return csum;
 145 }
 146
 147 static inline __wsum udp_csum(struct sk_buff *skb)
 148 {
 149         __wsum csum = csum_partial(skb_transport_header(skb),
 150                                    sizeof(struct udphdr), skb->csum);
 151
 152         for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
 153                 csum = csum_add(csum, skb->csum);
 154         }
 155         return csum;
 156 }
 157
 158 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 159 static inline void udp_lib_hash(struct sock *sk)
 160 {
 161         BUG();
 162 }
 163
 164 extern void udp_lib_unhash(struct sock *sk);
 165 extern void udp_lib_rehash(struct sock *sk, u16 new_hash);
 166
 167 static inline void udp_lib_close(struct sock *sk, long timeout)
 168 {
 169         sk_common_release(sk);
 170 }
 171
 172 extern int udp_lib_get_port(struct sock *sk, unsigned short snum,
 173                             int (*)(const struct sock *,const struct sock *),
 174                             unsigned int hash2_nulladdr);
 175
 176 /* net/ipv4/udp.c */
 177 extern int udp_get_port(struct sock *sk, unsigned short snum,
 178                         int (*saddr_cmp)(const struct sock *,
 179                                          const struct sock *));
 180 extern void udp_err(struct sk_buff *, u32);
 181 extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
 182                             struct msghdr *msg, size_t len);
 183 extern void udp_flush_pending_frames(struct sock *sk);
 184 extern int udp_rcv(struct sk_buff *skb);
 185 extern int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 186 extern int udp_disconnect(struct sock *sk, int flags);
 187 extern unsigned int udp_poll(struct file *file, struct socket *sock,
 188                              poll_table *wait);
 189 extern int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 190                               char __user *optval, int __user *optlen);
 191 extern int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 192                               char __user *optval, unsigned int optlen,
 193                               int (*push_pending_frames)(struct sock *));
 194 extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 195                                     __be32 daddr, __be16 dport,
 196                                     int dif);
 197 extern struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 198                                     __be32 daddr, __be16 dport,
 199                                     int dif, struct udp_table *tbl);
 200 extern struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
 201                                     const struct in6_addr *daddr, __be16 dport,
 202                                     int dif);
 203 extern struct sock *__udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
 204                                     const struct in6_addr *daddr, __be16 dport,
 205                                     int dif, struct udp_table *tbl);
 206
 207 /*
 208  *      SNMP statistics for UDP and UDP-Lite
 209  */
 210 #define UDP_INC_STATS_USER(net, field, is_udplite)            do { \
 211         if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
 212         else            SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
 213 #define UDP_INC_STATS_BH(net, field, is_udplite)              do { \
 214         if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
 215         else            SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
 216
 217 #define UDP6_INC_STATS_BH(net, field, is_udplite)           do { \
 218         if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
 219         else            SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
 220 } while(0)
 221 #define UDP6_INC_STATS_USER(net, field, __lite)             do { \
 222         if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
 223         else        SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
 224 } while(0)
 225
 226 #if IS_ENABLED(CONFIG_IPV6)
 227 #define UDPX_INC_STATS_BH(sk, field) \
 228         do { \
 229                 if ((sk)->sk_family == AF_INET) \
 230                         UDP_INC_STATS_BH(sock_net(sk), field, 0); \
 231                 else \
 232                         UDP6_INC_STATS_BH(sock_net(sk), field, 0); \
 233         } while (0);
 234 #else
 235 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
 236 #endif
 237
 238 /* /proc */
 239 int udp_seq_open(struct inode *inode, struct file *file);
 240
 241 struct udp_seq_afinfo {
 242         char                            *name;
 243         sa_family_t                     family;
 244         struct udp_table                *udp_table;
 245         const struct file_operations    *seq_fops;
 246         struct seq_operations           seq_ops;
 247 };
 248
 249 struct udp_iter_state {
 250         struct seq_net_private  p;
 251         sa_family_t             family;
 252         int                     bucket;
 253         struct udp_table        *udp_table;
 254 };
 255
 256 #ifdef CONFIG_PROC_FS
 257 extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 258 extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
 259
 260 extern int udp4_proc_init(void);
 261 extern void udp4_proc_exit(void);
 262 #endif
 263
 264 extern void udp_init(void);
 265
 266 extern int udp4_ufo_send_check(struct sk_buff *skb);
 267 extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 268         netdev_features_t features);
 269 #endif  /* _UDP_H */