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 */
  42struct 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 */
  61struct 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 */
  75struct udp_table {
  76        struct udp_hslot        *hash;
  77        struct udp_hslot        *hash2;
  78        unsigned int            mask;
  79        unsigned int            log;
  80};
  81extern struct udp_table udp_table;
  82extern void udp_table_init(struct udp_table *, const char *);
  83static 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 */
  92static 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
 107extern struct proto udp_prot;
 108
 109extern atomic_long_t udp_memory_allocated;
 110
 111/* sysctl variables for udp */
 112extern long sysctl_udp_mem[3];
 113extern int sysctl_udp_rmem_min;
 114extern int sysctl_udp_wmem_min;
 115
 116struct sk_buff;
 117
 118/*
 119 *      Generic checksumming routines for UDP(-Lite) v4 and v6
 120 */
 121static 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
 126static 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 */
 138static 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
 148static 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 */
 160static inline void udp_lib_hash(struct sock *sk)
 161{
 162        BUG();
 163}
 164
 165extern void udp_lib_unhash(struct sock *sk);
 166extern void udp_lib_rehash(struct sock *sk, u16 new_hash);
 167
 168static inline void udp_lib_close(struct sock *sk, long timeout)
 169{
 170        sk_common_release(sk);
 171}
 172
 173extern 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 */
 178extern int udp_get_port(struct sock *sk, unsigned short snum,
 179                        int (*saddr_cmp)(const struct sock *,
 180                                         const struct sock *));
 181extern void udp_err(struct sk_buff *, u32);
 182extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
 183                            struct msghdr *msg, size_t len);
 184extern void udp_flush_pending_frames(struct sock *sk);
 185extern int udp_rcv(struct sk_buff *skb);
 186extern int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 187extern int udp_disconnect(struct sock *sk, int flags);
 188extern unsigned int udp_poll(struct file *file, struct socket *sock,
 189                             poll_table *wait);
 190extern int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 191                              char __user *optval, int __user *optlen);
 192extern 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 *));
 195extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 196                                    __be32 daddr, __be16 dport,
 197                                    int dif);
 198extern struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 199                                    __be32 daddr, __be16 dport,
 200                                    int dif, struct udp_table *tbl);
 201extern 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);
 204extern 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 */
 240int udp_seq_open(struct inode *inode, struct file *file);
 241
 242struct 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
 250struct 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
 258extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 259extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
 260
 261extern int udp4_proc_init(void);
 262extern void udp4_proc_exit(void);
 263#endif
 264
 265extern void udp_init(void);
 266
 267extern int udp4_ufo_send_check(struct sk_buff *skb);
 268extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 269        netdev_features_t features);
 270extern void udp_encap_enable(void);
 271#if IS_ENABLED(CONFIG_IPV6)
 272extern void udpv6_encap_enable(void);
 273#endif
 274#endif  /* _UDP_H */
 275
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