LXR linux/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 */
  41struct udp_skb_cb {
  42        union {
  43                struct inet_skb_parm    h4;
  44#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
  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 */
  60struct 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 */
  74struct udp_table {
  75        struct udp_hslot        *hash;
  76        struct udp_hslot        *hash2;
  77        unsigned int            mask;
  78        unsigned int            log;
  79};
  80extern struct udp_table udp_table;
  81extern void udp_table_init(struct udp_table *, const char *);
  82static 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 */
  91static 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
 106extern struct proto udp_prot;
 107
 108extern atomic_t udp_memory_allocated;
 109
 110/* sysctl variables for udp */
 111extern int sysctl_udp_mem[3];
 112extern int sysctl_udp_rmem_min;
 113extern int sysctl_udp_wmem_min;
 114
 115struct sk_buff;
 116
 117/*
 118 *      Generic checksumming routines for UDP(-Lite) v4 and v6
 119 */
 120static 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
 125static 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 */
 137static 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/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 148static inline void udp_lib_hash(struct sock *sk)
 149{
 150        BUG();
 151}
 152
 153extern void udp_lib_unhash(struct sock *sk);
 154
 155static inline void udp_lib_close(struct sock *sk, long timeout)
 156{
 157        sk_common_release(sk);
 158}
 159
 160extern int      udp_lib_get_port(struct sock *sk, unsigned short snum,
 161                int (*)(const struct sock *,const struct sock *),
 162                unsigned int hash2_nulladdr);
 163
 164/* net/ipv4/udp.c */
 165extern int      udp_get_port(struct sock *sk, unsigned short snum,
 166                             int (*saddr_cmp)(const struct sock *, const struct sock *));
 167extern void     udp_err(struct sk_buff *, u32);
 168
 169extern int      udp_sendmsg(struct kiocb *iocb, struct sock *sk,
 170                            struct msghdr *msg, size_t len);
 171extern void     udp_flush_pending_frames(struct sock *sk);
 172
 173extern int      udp_rcv(struct sk_buff *skb);
 174extern int      udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 175extern int      udp_disconnect(struct sock *sk, int flags);
 176extern unsigned int udp_poll(struct file *file, struct socket *sock,
 177                             poll_table *wait);
 178extern int      udp_lib_getsockopt(struct sock *sk, int level, int optname,
 179                                   char __user *optval, int __user *optlen);
 180extern int      udp_lib_setsockopt(struct sock *sk, int level, int optname,
 181                                   char __user *optval, unsigned int optlen,
 182                                   int (*push_pending_frames)(struct sock *));
 183
 184extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 185                                    __be32 daddr, __be16 dport,
 186                                    int dif);
 187
 188/*
 189 *      SNMP statistics for UDP and UDP-Lite
 190 */
 191#define UDP_INC_STATS_USER(net, field, is_udplite)            do { \
 192        if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
 193        else            SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
 194#define UDP_INC_STATS_BH(net, field, is_udplite)              do { \
 195        if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
 196        else            SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
 197
 198#define UDP6_INC_STATS_BH(net, field, is_udplite)           do { \
 199        if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
 200        else            SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
 201} while(0)
 202#define UDP6_INC_STATS_USER(net, field, __lite)             do { \
 203        if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
 204        else        SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
 205} while(0)
 206
 207#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 208#define UDPX_INC_STATS_BH(sk, field) \
 209        do { \
 210                if ((sk)->sk_family == AF_INET) \
 211                        UDP_INC_STATS_BH(sock_net(sk), field, 0); \
 212                else \
 213                        UDP6_INC_STATS_BH(sock_net(sk), field, 0); \
 214        } while (0);
 215#else
 216#define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
 217#endif
 218
 219/* /proc */
 220struct udp_seq_afinfo {
 221        char                    *name;
 222        sa_family_t             family;
 223        struct udp_table        *udp_table;
 224        struct file_operations  seq_fops;
 225        struct seq_operations   seq_ops;
 226};
 227
 228struct udp_iter_state {
 229        struct seq_net_private  p;
 230        sa_family_t             family;
 231        int                     bucket;
 232        struct udp_table        *udp_table;
 233};
 234
 235#ifdef CONFIG_PROC_FS
 236extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 237extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
 238
 239extern int  udp4_proc_init(void);
 240extern void udp4_proc_exit(void);
 241#endif
 242
 243extern void udp_init(void);
 244
 245extern int udp4_ufo_send_check(struct sk_buff *skb);
 246extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features);
 247#endif  /* _UDP_H */
 248