LXR linux/include/net/udp.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4 *              operating system.  INET is implemented using the  BSD Socket
   5 *              interface as the means of communication with the user level.
   6 *
   7 *              Definitions for the UDP module.
   8 *
   9 * Version:     @(#)udp.h       1.0.2   05/07/93
  10 *
  11 * Authors:     Ross Biro
  12 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  13 *
  14 * Fixes:
  15 *              Alan Cox        : Turned on udp checksums. I don't want to
  16 *                                chase 'memory corruption' bugs that aren't!
  17 */
  18#ifndef _UDP_H
  19#define _UDP_H
  20
  21#include <linux/list.h>
  22#include <linux/bug.h>
  23#include <net/inet_sock.h>
  24#include <net/sock.h>
  25#include <net/snmp.h>
  26#include <net/ip.h>
  27#include <linux/ipv6.h>
  28#include <linux/seq_file.h>
  29#include <linux/poll.h>
  30
  31/**
  32 *      struct udp_skb_cb  -  UDP(-Lite) private variables
  33 *
  34 *      @header:      private variables used by IPv4/IPv6
  35 *      @cscov:       checksum coverage length (UDP-Lite only)
  36 *      @partial_cov: if set indicates partial csum coverage
  37 */
  38struct udp_skb_cb {
  39        union {
  40                struct inet_skb_parm    h4;
  41#if IS_ENABLED(CONFIG_IPV6)
  42                struct inet6_skb_parm   h6;
  43#endif
  44        } header;
  45        __u16           cscov;
  46        __u8            partial_cov;
  47};
  48#define UDP_SKB_CB(__skb)       ((struct udp_skb_cb *)((__skb)->cb))
  49
  50/**
  51 *      struct udp_hslot - UDP hash slot
  52 *
  53 *      @head:  head of list of sockets
  54 *      @count: number of sockets in 'head' list
  55 *      @lock:  spinlock protecting changes to head/count
  56 */
  57struct udp_hslot {
  58        struct hlist_head       head;
  59        int                     count;
  60        spinlock_t              lock;
  61} __attribute__((aligned(2 * sizeof(long))));
  62
  63/**
  64 *      struct udp_table - UDP table
  65 *
  66 *      @hash:  hash table, sockets are hashed on (local port)
  67 *      @hash2: hash table, sockets are hashed on (local port, local address)
  68 *      @mask:  number of slots in hash tables, minus 1
  69 *      @log:   log2(number of slots in hash table)
  70 */
  71struct udp_table {
  72        struct udp_hslot        *hash;
  73        struct udp_hslot        *hash2;
  74        unsigned int            mask;
  75        unsigned int            log;
  76};
  77extern struct udp_table udp_table;
  78void udp_table_init(struct udp_table *, const char *);
  79static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
  80                                             struct net *net, unsigned int num)
  81{
  82        return &table->hash[udp_hashfn(net, num, table->mask)];
  83}
  84/*
  85 * For secondary hash, net_hash_mix() is performed before calling
  86 * udp_hashslot2(), this explains difference with udp_hashslot()
  87 */
  88static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
  89                                              unsigned int hash)
  90{
  91        return &table->hash2[hash & table->mask];
  92}
  93
  94extern struct proto udp_prot;
  95
  96extern atomic_long_t udp_memory_allocated;
  97
  98/* sysctl variables for udp */
  99extern long sysctl_udp_mem[3];
 100extern int sysctl_udp_rmem_min;
 101extern int sysctl_udp_wmem_min;
 102
 103struct sk_buff;
 104
 105/*
 106 *      Generic checksumming routines for UDP(-Lite) v4 and v6
 107 */
 108static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
 109{
 110        return (UDP_SKB_CB(skb)->cscov == skb->len ?
 111                __skb_checksum_complete(skb) :
 112                __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
 113}
 114
 115static inline int udp_lib_checksum_complete(struct sk_buff *skb)
 116{
 117        return !skb_csum_unnecessary(skb) &&
 118                __udp_lib_checksum_complete(skb);
 119}
 120
 121/**
 122 *      udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
 123 *      @sk:    socket we are writing to
 124 *      @skb:   sk_buff containing the filled-in UDP header
 125 *              (checksum field must be zeroed out)
 126 */
 127static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 128{
 129        __wsum csum = csum_partial(skb_transport_header(skb),
 130                                   sizeof(struct udphdr), 0);
 131        skb_queue_walk(&sk->sk_write_queue, skb) {
 132                csum = csum_add(csum, skb->csum);
 133        }
 134        return csum;
 135}
 136
 137static inline __wsum udp_csum(struct sk_buff *skb)
 138{
 139        __wsum csum = csum_partial(skb_transport_header(skb),
 140                                   sizeof(struct udphdr), skb->csum);
 141
 142        for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
 143                csum = csum_add(csum, skb->csum);
 144        }
 145        return csum;
 146}
 147
 148static inline __sum16 udp_v4_check(int len, __be32 saddr,
 149                                   __be32 daddr, __wsum base)
 150{
 151        return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
 152}
 153
 154void udp_set_csum(bool nocheck, struct sk_buff *skb,
 155                  __be32 saddr, __be32 daddr, int len);
 156
 157static inline void udp_csum_pull_header(struct sk_buff *skb)
 158{
 159        if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
 160                skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
 161                                         skb->csum);
 162        skb_pull_rcsum(skb, sizeof(struct udphdr));
 163        UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
 164}
 165
 166typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
 167                                     __be16 dport);
 168
 169struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 170                                struct udphdr *uh, udp_lookup_t lookup);
 171int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
 172
 173struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 174                                  netdev_features_t features);
 175
 176static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
 177{
 178        struct udphdr *uh;
 179        unsigned int hlen, off;
 180
 181        off  = skb_gro_offset(skb);
 182        hlen = off + sizeof(*uh);
 183        uh   = skb_gro_header_fast(skb, off);
 184        if (skb_gro_header_hard(skb, hlen))
 185                uh = skb_gro_header_slow(skb, hlen, off);
 186
 187        return uh;
 188}
 189
 190/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 191static inline int udp_lib_hash(struct sock *sk)
 192{
 193        BUG();
 194        return 0;
 195}
 196
 197void udp_lib_unhash(struct sock *sk);
 198void udp_lib_rehash(struct sock *sk, u16 new_hash);
 199
 200static inline void udp_lib_close(struct sock *sk, long timeout)
 201{
 202        sk_common_release(sk);
 203}
 204
 205int udp_lib_get_port(struct sock *sk, unsigned short snum,
 206                     unsigned int hash2_nulladdr);
 207
 208u32 udp_flow_hashrnd(void);
 209
 210static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
 211                                       int min, int max, bool use_eth)
 212{
 213        u32 hash;
 214
 215        if (min >= max) {
 216                /* Use default range */
 217                inet_get_local_port_range(net, &min, &max);
 218        }
 219
 220        hash = skb_get_hash(skb);
 221        if (unlikely(!hash)) {
 222                if (use_eth) {
 223                        /* Can't find a normal hash, caller has indicated an
 224                         * Ethernet packet so use that to compute a hash.
 225                         */
 226                        hash = jhash(skb->data, 2 * ETH_ALEN,
 227                                     (__force u32) skb->protocol);
 228                } else {
 229                        /* Can't derive any sort of hash for the packet, set
 230                         * to some consistent random value.
 231                         */
 232                        hash = udp_flow_hashrnd();
 233                }
 234        }
 235
 236        /* Since this is being sent on the wire obfuscate hash a bit
 237         * to minimize possbility that any useful information to an
 238         * attacker is leaked. Only upper 16 bits are relevant in the
 239         * computation for 16 bit port value.
 240         */
 241        hash ^= hash << 16;
 242
 243        return htons((((u64) hash * (max - min)) >> 32) + min);
 244}
 245
 246static inline int udp_rqueue_get(struct sock *sk)
 247{
 248        return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
 249}
 250
 251static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
 252                                       int dif, int sdif)
 253{
 254#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 255        return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept,
 256                                 bound_dev_if, dif, sdif);
 257#else
 258        return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
 259#endif
 260}
 261
 262/* net/ipv4/udp.c */
 263void udp_destruct_sock(struct sock *sk);
 264void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
 265int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
 266void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
 267struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 268                               int noblock, int *off, int *err);
 269static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
 270                                           int noblock, int *err)
 271{
 272        int off = 0;
 273
 274        return __skb_recv_udp(sk, flags, noblock, &off, err);
 275}
 276
 277int udp_v4_early_demux(struct sk_buff *skb);
 278bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
 279int udp_get_port(struct sock *sk, unsigned short snum,
 280                 int (*saddr_cmp)(const struct sock *,
 281                                  const struct sock *));
 282int udp_err(struct sk_buff *, u32);
 283int udp_abort(struct sock *sk, int err);
 284int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 285int udp_push_pending_frames(struct sock *sk);
 286void udp_flush_pending_frames(struct sock *sk);
 287int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
 288void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 289int udp_rcv(struct sk_buff *skb);
 290int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 291int udp_init_sock(struct sock *sk);
 292int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 293int __udp_disconnect(struct sock *sk, int flags);
 294int udp_disconnect(struct sock *sk, int flags);
 295__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 296struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 297                                       netdev_features_t features,
 298                                       bool is_ipv6);
 299int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 300                       char __user *optval, int __user *optlen);
 301int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 302                       char __user *optval, unsigned int optlen,
 303                       int (*push_pending_frames)(struct sock *));
 304struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 305                             __be32 daddr, __be16 dport, int dif);
 306struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 307                               __be32 daddr, __be16 dport, int dif, int sdif,
 308                               struct udp_table *tbl, struct sk_buff *skb);
 309struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
 310                                 __be16 sport, __be16 dport);
 311struct sock *udp6_lib_lookup(struct net *net,
 312                             const struct in6_addr *saddr, __be16 sport,
 313                             const struct in6_addr *daddr, __be16 dport,
 314                             int dif);
 315struct sock *__udp6_lib_lookup(struct net *net,
 316                               const struct in6_addr *saddr, __be16 sport,
 317                               const struct in6_addr *daddr, __be16 dport,
 318                               int dif, int sdif, struct udp_table *tbl,
 319                               struct sk_buff *skb);
 320struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
 321                                 __be16 sport, __be16 dport);
 322
 323/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
 324 * possibly multiple cache miss on dequeue()
 325 */
 326struct udp_dev_scratch {
 327        /* skb->truesize and the stateless bit are embedded in a single field;
 328         * do not use a bitfield since the compiler emits better/smaller code
 329         * this way
 330         */
 331        u32 _tsize_state;
 332
 333#if BITS_PER_LONG == 64
 334        /* len and the bit needed to compute skb_csum_unnecessary
 335         * will be on cold cache lines at recvmsg time.
 336         * skb->len can be stored on 16 bits since the udp header has been
 337         * already validated and pulled.
 338         */
 339        u16 len;
 340        bool is_linear;
 341        bool csum_unnecessary;
 342#endif
 343};
 344
 345static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
 346{
 347        return (struct udp_dev_scratch *)&skb->dev_scratch;
 348}
 349
 350#if BITS_PER_LONG == 64
 351static inline unsigned int udp_skb_len(struct sk_buff *skb)
 352{
 353        return udp_skb_scratch(skb)->len;
 354}
 355
 356static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 357{
 358        return udp_skb_scratch(skb)->csum_unnecessary;
 359}
 360
 361static inline bool udp_skb_is_linear(struct sk_buff *skb)
 362{
 363        return udp_skb_scratch(skb)->is_linear;
 364}
 365
 366#else
 367static inline unsigned int udp_skb_len(struct sk_buff *skb)
 368{
 369        return skb->len;
 370}
 371
 372static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 373{
 374        return skb_csum_unnecessary(skb);
 375}
 376
 377static inline bool udp_skb_is_linear(struct sk_buff *skb)
 378{
 379        return !skb_is_nonlinear(skb);
 380}
 381#endif
 382
 383static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
 384                                  struct iov_iter *to)
 385{
 386        int n;
 387
 388        n = copy_to_iter(skb->data + off, len, to);
 389        if (n == len)
 390                return 0;
 391
 392        iov_iter_revert(to, n);
 393        return -EFAULT;
 394}
 395
 396/*
 397 *      SNMP statistics for UDP and UDP-Lite
 398 */
 399#define UDP_INC_STATS(net, field, is_udplite)                 do { \
 400        if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
 401        else            SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
 402#define __UDP_INC_STATS(net, field, is_udplite)               do { \
 403        if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
 404        else            __SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)
 405
 406#define __UDP6_INC_STATS(net, field, is_udplite)            do { \
 407        if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
 408        else            __SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
 409} while(0)
 410#define UDP6_INC_STATS(net, field, __lite)                  do { \
 411        if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
 412        else        SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
 413} while(0)
 414
 415#if IS_ENABLED(CONFIG_IPV6)
 416#define __UDPX_MIB(sk, ipv4)                                            \
 417({                                                                      \
 418        ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
 419                                 sock_net(sk)->mib.udp_statistics) :    \
 420                (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
 421                                 sock_net(sk)->mib.udp_stats_in6);      \
 422})
 423#else
 424#define __UDPX_MIB(sk, ipv4)                                            \
 425({                                                                      \
 426        IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics :         \
 427                         sock_net(sk)->mib.udp_statistics;              \
 428})
 429#endif
 430
 431#define __UDPX_INC_STATS(sk, field) \
 432        __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
 433
 434#ifdef CONFIG_PROC_FS
 435struct udp_seq_afinfo {
 436        sa_family_t                     family;
 437        struct udp_table                *udp_table;
 438};
 439
 440struct udp_iter_state {
 441        struct seq_net_private  p;
 442        int                     bucket;
 443};
 444
 445void *udp_seq_start(struct seq_file *seq, loff_t *pos);
 446void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
 447void udp_seq_stop(struct seq_file *seq, void *v);
 448
 449extern const struct seq_operations udp_seq_ops;
 450extern const struct seq_operations udp6_seq_ops;
 451
 452int udp4_proc_init(void);
 453void udp4_proc_exit(void);
 454#endif /* CONFIG_PROC_FS */
 455
 456int udpv4_offload_init(void);
 457
 458void udp_init(void);
 459
 460DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
 461void udp_encap_enable(void);
 462#if IS_ENABLED(CONFIG_IPV6)
 463DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
 464void udpv6_encap_enable(void);
 465#endif
 466
 467static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
 468                                              struct sk_buff *skb, bool ipv4)
 469{
 470        netdev_features_t features = NETIF_F_SG;
 471        struct sk_buff *segs;
 472
 473        /* Avoid csum recalculation by skb_segment unless userspace explicitly
 474         * asks for the final checksum values
 475         */
 476        if (!inet_get_convert_csum(sk))
 477                features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
 478
 479        /* the GSO CB lays after the UDP one, no need to save and restore any
 480         * CB fragment
 481         */
 482        segs = __skb_gso_segment(skb, features, false);
 483        if (unlikely(IS_ERR_OR_NULL(segs))) {
 484                int segs_nr = skb_shinfo(skb)->gso_segs;
 485
 486                atomic_add(segs_nr, &sk->sk_drops);
 487                SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
 488                kfree_skb(skb);
 489                return NULL;
 490        }
 491
 492        consume_skb(skb);
 493        return segs;
 494}
 495
 496#endif  /* _UDP_H */
 497