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_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
 161static inline void udp_csum_pull_header(struct sk_buff *skb)
 162{
 163        if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
 164                skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
 165                                         skb->csum);
 166        skb_pull_rcsum(skb, sizeof(struct udphdr));
 167        UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
 168}
 169
 170typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
 171                                     __be16 dport);
 172
 173struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 174                                struct udphdr *uh, udp_lookup_t lookup);
 175int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
 176
 177struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 178                                  netdev_features_t features);
 179
 180static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
 181{
 182        struct udphdr *uh;
 183        unsigned int hlen, off;
 184
 185        off  = skb_gro_offset(skb);
 186        hlen = off + sizeof(*uh);
 187        uh   = skb_gro_header_fast(skb, off);
 188        if (skb_gro_header_hard(skb, hlen))
 189                uh = skb_gro_header_slow(skb, hlen, off);
 190
 191        return uh;
 192}
 193
 194/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 195static inline int udp_lib_hash(struct sock *sk)
 196{
 197        BUG();
 198        return 0;
 199}
 200
 201void udp_lib_unhash(struct sock *sk);
 202void udp_lib_rehash(struct sock *sk, u16 new_hash);
 203
 204static inline void udp_lib_close(struct sock *sk, long timeout)
 205{
 206        sk_common_release(sk);
 207}
 208
 209int udp_lib_get_port(struct sock *sk, unsigned short snum,
 210                     unsigned int hash2_nulladdr);
 211
 212u32 udp_flow_hashrnd(void);
 213
 214static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
 215                                       int min, int max, bool use_eth)
 216{
 217        u32 hash;
 218
 219        if (min >= max) {
 220                /* Use default range */
 221                inet_get_local_port_range(net, &min, &max);
 222        }
 223
 224        hash = skb_get_hash(skb);
 225        if (unlikely(!hash)) {
 226                if (use_eth) {
 227                        /* Can't find a normal hash, caller has indicated an
 228                         * Ethernet packet so use that to compute a hash.
 229                         */
 230                        hash = jhash(skb->data, 2 * ETH_ALEN,
 231                                     (__force u32) skb->protocol);
 232                } else {
 233                        /* Can't derive any sort of hash for the packet, set
 234                         * to some consistent random value.
 235                         */
 236                        hash = udp_flow_hashrnd();
 237                }
 238        }
 239
 240        /* Since this is being sent on the wire obfuscate hash a bit
 241         * to minimize possbility that any useful information to an
 242         * attacker is leaked. Only upper 16 bits are relevant in the
 243         * computation for 16 bit port value.
 244         */
 245        hash ^= hash << 16;
 246
 247        return htons((((u64) hash * (max - min)) >> 32) + min);
 248}
 249
 250static inline int udp_rqueue_get(struct sock *sk)
 251{
 252        return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
 253}
 254
 255/* net/ipv4/udp.c */
 256void udp_destruct_sock(struct sock *sk);
 257void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
 258int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
 259void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
 260struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 261                               int noblock, int *peeked, int *off, int *err);
 262static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
 263                                           int noblock, int *err)
 264{
 265        int peeked, off = 0;
 266
 267        return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
 268}
 269
 270int udp_v4_early_demux(struct sk_buff *skb);
 271bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
 272int udp_get_port(struct sock *sk, unsigned short snum,
 273                 int (*saddr_cmp)(const struct sock *,
 274                                  const struct sock *));
 275void udp_err(struct sk_buff *, u32);
 276int udp_abort(struct sock *sk, int err);
 277int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 278int udp_push_pending_frames(struct sock *sk);
 279void udp_flush_pending_frames(struct sock *sk);
 280int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
 281void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 282int udp_rcv(struct sk_buff *skb);
 283int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 284int udp_init_sock(struct sock *sk);
 285int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 286int __udp_disconnect(struct sock *sk, int flags);
 287int udp_disconnect(struct sock *sk, int flags);
 288__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 289struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 290                                       netdev_features_t features,
 291                                       bool is_ipv6);
 292int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 293                       char __user *optval, int __user *optlen);
 294int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 295                       char __user *optval, unsigned int optlen,
 296                       int (*push_pending_frames)(struct sock *));
 297struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 298                             __be32 daddr, __be16 dport, int dif);
 299struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 300                               __be32 daddr, __be16 dport, int dif, int sdif,
 301                               struct udp_table *tbl, struct sk_buff *skb);
 302struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
 303                                 __be16 sport, __be16 dport);
 304struct sock *udp6_lib_lookup(struct net *net,
 305                             const struct in6_addr *saddr, __be16 sport,
 306                             const struct in6_addr *daddr, __be16 dport,
 307                             int dif);
 308struct sock *__udp6_lib_lookup(struct net *net,
 309                               const struct in6_addr *saddr, __be16 sport,
 310                               const struct in6_addr *daddr, __be16 dport,
 311                               int dif, int sdif, struct udp_table *tbl,
 312                               struct sk_buff *skb);
 313struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
 314                                 __be16 sport, __be16 dport);
 315
 316/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
 317 * possibly multiple cache miss on dequeue()
 318 */
 319struct udp_dev_scratch {
 320        /* skb->truesize and the stateless bit are embedded in a single field;
 321         * do not use a bitfield since the compiler emits better/smaller code
 322         * this way
 323         */
 324        u32 _tsize_state;
 325
 326#if BITS_PER_LONG == 64
 327        /* len and the bit needed to compute skb_csum_unnecessary
 328         * will be on cold cache lines at recvmsg time.
 329         * skb->len can be stored on 16 bits since the udp header has been
 330         * already validated and pulled.
 331         */
 332        u16 len;
 333        bool is_linear;
 334        bool csum_unnecessary;
 335#endif
 336};
 337
 338static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
 339{
 340        return (struct udp_dev_scratch *)&skb->dev_scratch;
 341}
 342
 343#if BITS_PER_LONG == 64
 344static inline unsigned int udp_skb_len(struct sk_buff *skb)
 345{
 346        return udp_skb_scratch(skb)->len;
 347}
 348
 349static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 350{
 351        return udp_skb_scratch(skb)->csum_unnecessary;
 352}
 353
 354static inline bool udp_skb_is_linear(struct sk_buff *skb)
 355{
 356        return udp_skb_scratch(skb)->is_linear;
 357}
 358
 359#else
 360static inline unsigned int udp_skb_len(struct sk_buff *skb)
 361{
 362        return skb->len;
 363}
 364
 365static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 366{
 367        return skb_csum_unnecessary(skb);
 368}
 369
 370static inline bool udp_skb_is_linear(struct sk_buff *skb)
 371{
 372        return !skb_is_nonlinear(skb);
 373}
 374#endif
 375
 376static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
 377                                  struct iov_iter *to)
 378{
 379        int n;
 380
 381        n = copy_to_iter(skb->data + off, len, to);
 382        if (n == len)
 383                return 0;
 384
 385        iov_iter_revert(to, n);
 386        return -EFAULT;
 387}
 388
 389/*
 390 *      SNMP statistics for UDP and UDP-Lite
 391 */
 392#define UDP_INC_STATS(net, field, is_udplite)                 do { \
 393        if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
 394        else            SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
 395#define __UDP_INC_STATS(net, field, is_udplite)               do { \
 396        if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
 397        else            __SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)
 398
 399#define __UDP6_INC_STATS(net, field, is_udplite)            do { \
 400        if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
 401        else            __SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
 402} while(0)
 403#define UDP6_INC_STATS(net, field, __lite)                  do { \
 404        if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
 405        else        SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
 406} while(0)
 407
 408#if IS_ENABLED(CONFIG_IPV6)
 409#define __UDPX_INC_STATS(sk, field)                                     \
 410do {                                                                    \
 411        if ((sk)->sk_family == AF_INET)                                 \
 412                __UDP_INC_STATS(sock_net(sk), field, 0);                \
 413        else                                                            \
 414                __UDP6_INC_STATS(sock_net(sk), field, 0);               \
 415} while (0)
 416#else
 417#define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
 418#endif
 419
 420#ifdef CONFIG_PROC_FS
 421struct udp_seq_afinfo {
 422        sa_family_t                     family;
 423        struct udp_table                *udp_table;
 424};
 425
 426struct udp_iter_state {
 427        struct seq_net_private  p;
 428        int                     bucket;
 429};
 430
 431void *udp_seq_start(struct seq_file *seq, loff_t *pos);
 432void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
 433void udp_seq_stop(struct seq_file *seq, void *v);
 434
 435extern const struct seq_operations udp_seq_ops;
 436extern const struct seq_operations udp6_seq_ops;
 437
 438int udp4_proc_init(void);
 439void udp4_proc_exit(void);
 440#endif /* CONFIG_PROC_FS */
 441
 442int udpv4_offload_init(void);
 443
 444void udp_init(void);
 445
 446void udp_encap_enable(void);
 447#if IS_ENABLED(CONFIG_IPV6)
 448void udpv6_encap_enable(void);
 449#endif
 450
 451#endif  /* _UDP_H */
 452