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  */
  42 struct 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  */
  61 struct 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  */
  75 struct udp_table {
  76         struct udp_hslot        *hash;
  77         struct udp_hslot        *hash2;
  78         unsigned int            mask;
  79         unsigned int            log;
  80 };
  81 extern struct udp_table udp_table;
  82 void udp_table_init(struct udp_table *, const char *);
  83 static 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  */
  92 static 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 extern struct proto udp_prot;
  99
 100 extern atomic_long_t udp_memory_allocated;
 101
 102 /* sysctl variables for udp */
 103 extern long sysctl_udp_mem[3];
 104 extern int sysctl_udp_rmem_min;
 105 extern int sysctl_udp_wmem_min;
 106
 107 struct sk_buff;
 108
 109 /*
 110  *      Generic checksumming routines for UDP(-Lite) v4 and v6
 111  */
 112 static 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
 119 static 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  */
 131 static 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
 141 static 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
 152 static 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
 158 void udp_set_csum(bool nocheck, struct sk_buff *skb,
 159                   __be32 saddr, __be32 daddr, int len);
 160
 161 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
 162                                  struct udphdr *uh);
 163 int udp_gro_complete(struct sk_buff *skb, int nhoff);
 164
 165 static 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 */
 180 static inline void udp_lib_hash(struct sock *sk)
 181 {
 182         BUG();
 183 }
 184
 185 void udp_lib_unhash(struct sock *sk);
 186 void udp_lib_rehash(struct sock *sk, u16 new_hash);
 187
 188 static inline void udp_lib_close(struct sock *sk, long timeout)
 189 {
 190         sk_common_release(sk);
 191 }
 192
 193 int udp_lib_get_port(struct sock *sk, unsigned short snum,
 194                      int (*)(const struct sock *, const struct sock *),
 195                      unsigned int hash2_nulladdr);
 196
 197 u32 udp_flow_hashrnd(void);
 198
 199 static 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 */
 236 void udp_v4_early_demux(struct sk_buff *skb);
 237 int udp_get_port(struct sock *sk, unsigned short snum,
 238                  int (*saddr_cmp)(const struct sock *,
 239                                   const struct sock *));
 240 void udp_err(struct sk_buff *, u32);
 241 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 242 int udp_push_pending_frames(struct sock *sk);
 243 void udp_flush_pending_frames(struct sock *sk);
 244 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 245 int udp_rcv(struct sk_buff *skb);
 246 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 247 int udp_disconnect(struct sock *sk, int flags);
 248 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 249 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 250                                        netdev_features_t features,
 251                                        bool is_ipv6);
 252 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 253                        char __user *optval, int __user *optlen);
 254 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 255                        char __user *optval, unsigned int optlen,
 256                        int (*push_pending_frames)(struct sock *));
 257 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 258                              __be32 daddr, __be16 dport, int dif);
 259 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 260                                __be32 daddr, __be16 dport, int dif,
 261                                struct udp_table *tbl);
 262 struct 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);
 266 struct 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
 271 /*
 272  *      SNMP statistics for UDP and UDP-Lite
 273  */
 274 #define UDP_INC_STATS_USER(net, field, is_udplite)            do { \
 275         if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
 276         else            SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
 277 #define UDP_INC_STATS_BH(net, field, is_udplite)              do { \
 278         if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
 279         else            SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
 280
 281 #define UDP6_INC_STATS_BH(net, field, is_udplite)           do { \
 282         if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
 283         else            SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
 284 } while(0)
 285 #define UDP6_INC_STATS_USER(net, field, __lite)             do { \
 286         if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
 287         else        SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
 288 } while(0)
 289
 290 #if IS_ENABLED(CONFIG_IPV6)
 291 #define UDPX_INC_STATS_BH(sk, field)                                    \
 292 do {                                                                    \
 293         if ((sk)->sk_family == AF_INET)                                 \
 294                 UDP_INC_STATS_BH(sock_net(sk), field, 0);               \
 295         else                                                            \
 296                 UDP6_INC_STATS_BH(sock_net(sk), field, 0);              \
 297 } while (0)
 298 #else
 299 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
 300 #endif
 301
 302 /* /proc */
 303 int udp_seq_open(struct inode *inode, struct file *file);
 304
 305 struct udp_seq_afinfo {
 306         char                            *name;
 307         sa_family_t                     family;
 308         struct udp_table                *udp_table;
 309         const struct file_operations    *seq_fops;
 310         struct seq_operations           seq_ops;
 311 };
 312
 313 struct udp_iter_state {
 314         struct seq_net_private  p;
 315         sa_family_t             family;
 316         int                     bucket;
 317         struct udp_table        *udp_table;
 318 };
 319
 320 #ifdef CONFIG_PROC_FS
 321 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 322 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
 323
 324 int udp4_proc_init(void);
 325 void udp4_proc_exit(void);
 326 #endif
 327
 328 int udpv4_offload_init(void);
 329
 330 void udp_init(void);
 331
 332 void udp_encap_enable(void);
 333 #if IS_ENABLED(CONFIG_IPV6)
 334 void udpv6_encap_enable(void);
 335 #endif
 336 #endif  /* _UDP_H */