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 <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;
  82void 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
  98extern struct proto udp_prot;
  99
 100extern atomic_long_t udp_memory_allocated;
 101
 102/* sysctl variables for udp */
 103extern long sysctl_udp_mem[3];
 104extern int sysctl_udp_rmem_min;
 105extern int sysctl_udp_wmem_min;
 106
 107struct sk_buff;
 108
 109/*
 110 *      Generic checksumming routines for UDP(-Lite) v4 and v6
 111 */
 112static 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
 119static 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 */
 131static 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
 141static 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
 152static 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
 158void udp_set_csum(bool nocheck, struct sk_buff *skb,
 159                  __be32 saddr, __be32 daddr, int len);
 160
 161struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
 162                                 struct udphdr *uh);
 163int udp_gro_complete(struct sk_buff *skb, int nhoff);
 164
 165static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
 166{
 167        struct udphdr *uh;
 168        unsigned int hlen, off;
 169
 170        off  = skb_gro_offset(skb);
 171        hlen = off + sizeof(*uh);
 172        uh   = skb_gro_header_fast(skb, off);
 173        if (skb_gro_header_hard(skb, hlen))
 174                uh = skb_gro_header_slow(skb, hlen, off);
 175
 176        return uh;
 177}
 178
 179/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 180static inline void udp_lib_hash(struct sock *sk)
 181{
 182        BUG();
 183}
 184
 185void udp_lib_unhash(struct sock *sk);
 186void udp_lib_rehash(struct sock *sk, u16 new_hash);
 187
 188static inline void udp_lib_close(struct sock *sk, long timeout)
 189{
 190        sk_common_release(sk);
 191}
 192
 193int udp_lib_get_port(struct sock *sk, unsigned short snum,
 194                     int (*)(const struct sock *, const struct sock *, bool),
 195                     unsigned int hash2_nulladdr);
 196
 197u32 udp_flow_hashrnd(void);
 198
 199static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
 200                                       int min, int max, bool use_eth)
 201{
 202        u32 hash;
 203
 204        if (min >= max) {
 205                /* Use default range */
 206                inet_get_local_port_range(net, &min, &max);
 207        }
 208
 209        hash = skb_get_hash(skb);
 210        if (unlikely(!hash)) {
 211                if (use_eth) {
 212                        /* Can't find a normal hash, caller has indicated an
 213                         * Ethernet packet so use that to compute a hash.
 214                         */
 215                        hash = jhash(skb->data, 2 * ETH_ALEN,
 216                                     (__force u32) skb->protocol);
 217                } else {
 218                        /* Can't derive any sort of hash for the packet, set
 219                         * to some consistent random value.
 220                         */
 221                        hash = udp_flow_hashrnd();
 222                }
 223        }
 224
 225        /* Since this is being sent on the wire obfuscate hash a bit
 226         * to minimize possbility that any useful information to an
 227         * attacker is leaked. Only upper 16 bits are relevant in the
 228         * computation for 16 bit port value.
 229         */
 230        hash ^= hash << 16;
 231
 232        return htons((((u64) hash * (max - min)) >> 32) + min);
 233}
 234
 235/* net/ipv4/udp.c */
 236void udp_v4_early_demux(struct sk_buff *skb);
 237int udp_get_port(struct sock *sk, unsigned short snum,
 238                 int (*saddr_cmp)(const struct sock *,
 239                                  const struct sock *));
 240void udp_err(struct sk_buff *, u32);
 241int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 242int udp_push_pending_frames(struct sock *sk);
 243void udp_flush_pending_frames(struct sock *sk);
 244void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 245int udp_rcv(struct sk_buff *skb);
 246int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 247int udp_disconnect(struct sock *sk, int flags);
 248unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 249struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 250                                       netdev_features_t features,
 251                                       bool is_ipv6);
 252int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 253                       char __user *optval, int __user *optlen);
 254int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 255                       char __user *optval, unsigned int optlen,
 256                       int (*push_pending_frames)(struct sock *));
 257struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 258                             __be32 daddr, __be16 dport, int dif);
 259struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 260                               __be32 daddr, __be16 dport, int dif,
 261                               struct udp_table *tbl, struct sk_buff *skb);
 262struct sock *udp6_lib_lookup(struct net *net,
 263                             const struct in6_addr *saddr, __be16 sport,
 264                             const struct in6_addr *daddr, __be16 dport,
 265                             int dif);
 266struct sock *__udp6_lib_lookup(struct net *net,
 267                               const struct in6_addr *saddr, __be16 sport,
 268                               const struct in6_addr *daddr, __be16 dport,
 269                               int dif, struct udp_table *tbl,
 270                               struct sk_buff *skb);
 271
 272/*
 273 *      SNMP statistics for UDP and UDP-Lite
 274 */
 275#define UDP_INC_STATS_USER(net, field, is_udplite)            do { \
 276        if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
 277        else            SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
 278#define UDP_INC_STATS_BH(net, field, is_udplite)              do { \
 279        if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
 280        else            SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
 281
 282#define UDP6_INC_STATS_BH(net, field, is_udplite)           do { \
 283        if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
 284        else            SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
 285} while(0)
 286#define UDP6_INC_STATS_USER(net, field, __lite)             do { \
 287        if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
 288        else        SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
 289} while(0)
 290
 291#if IS_ENABLED(CONFIG_IPV6)
 292#define UDPX_INC_STATS_BH(sk, field)                                    \
 293do {                                                                    \
 294        if ((sk)->sk_family == AF_INET)                                 \
 295                UDP_INC_STATS_BH(sock_net(sk), field, 0);               \
 296        else                                                            \
 297                UDP6_INC_STATS_BH(sock_net(sk), field, 0);              \
 298} while (0)
 299#else
 300#define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
 301#endif
 302
 303/* /proc */
 304int udp_seq_open(struct inode *inode, struct file *file);
 305
 306struct udp_seq_afinfo {
 307        char                            *name;
 308        sa_family_t                     family;
 309        struct udp_table                *udp_table;
 310        const struct file_operations    *seq_fops;
 311        struct seq_operations           seq_ops;
 312};
 313
 314struct udp_iter_state {
 315        struct seq_net_private  p;
 316        sa_family_t             family;
 317        int                     bucket;
 318        struct udp_table        *udp_table;
 319};
 320
 321#ifdef CONFIG_PROC_FS
 322int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 323void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
 324
 325int udp4_proc_init(void);
 326void udp4_proc_exit(void);
 327#endif
 328
 329int udpv4_offload_init(void);
 330
 331void udp_init(void);
 332
 333void udp_encap_enable(void);
 334#if IS_ENABLED(CONFIG_IPV6)
 335void udpv6_encap_enable(void);
 336#endif
 337#endif  /* _UDP_H */
 338