include/linux/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 protocol.
   8  *
   9  * Version:     @(#)udp.h       1.0.2   04/28/93
  10  *
  11  * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  */
  13 #ifndef _LINUX_UDP_H
  14 #define _LINUX_UDP_H
  15
  16 #include <net/inet_sock.h>
  17 #include <linux/skbuff.h>
  18 #include <net/netns/hash.h>
  19 #include <uapi/linux/udp.h>
  20
  21 static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
  22 {
  23         return (struct udphdr *)skb_transport_header(skb);
  24 }
  25
  26 #define UDP_HTABLE_SIZE_MIN_PERNET      128
  27 #define UDP_HTABLE_SIZE_MIN             (IS_ENABLED(CONFIG_BASE_SMALL) ? 128 : 256)
  28 #define UDP_HTABLE_SIZE_MAX             65536
  29
  30 static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
  31 {
  32         return (num + net_hash_mix(net)) & mask;
  33 }
  34
  35 enum {
  36         UDP_FLAGS_CORK,         /* Cork is required */
  37         UDP_FLAGS_NO_CHECK6_TX, /* Send zero UDP6 checksums on TX? */
  38         UDP_FLAGS_NO_CHECK6_RX, /* Allow zero UDP6 checksums on RX? */
  39         UDP_FLAGS_GRO_ENABLED,  /* Request GRO aggregation */
  40         UDP_FLAGS_ACCEPT_FRAGLIST,
  41         UDP_FLAGS_ACCEPT_L4,
  42         UDP_FLAGS_ENCAP_ENABLED, /* This socket enabled encap */
  43         UDP_FLAGS_UDPLITE_SEND_CC, /* set via udplite setsockopt */
  44         UDP_FLAGS_UDPLITE_RECV_CC, /* set via udplite setsockopt */
  45 };
  46
  47 struct udp_sock {
  48         /* inet_sock has to be the first member */
  49         struct inet_sock inet;
  50 #define udp_port_hash           inet.sk.__sk_common.skc_u16hashes[0]
  51 #define udp_portaddr_hash       inet.sk.__sk_common.skc_u16hashes[1]
  52 #define udp_portaddr_node       inet.sk.__sk_common.skc_portaddr_node
  53
  54         unsigned long    udp_flags;
  55
  56         int              pending;       /* Any pending frames ? */
  57         __u8             encap_type;    /* Is this an Encapsulation socket? */
  58
  59 #if !IS_ENABLED(CONFIG_BASE_SMALL)
  60         /* For UDP 4-tuple hash */
  61         __u16 udp_lrpa_hash;
  62         struct hlist_nulls_node udp_lrpa_node;
  63 #endif
  64
  65         /*
  66          * Following member retains the information to create a UDP header
  67          * when the socket is uncorked.
  68          */
  69         __u16            len;           /* total length of pending frames */
  70         __u16            gso_size;
  71         /*
  72          * Fields specific to UDP-Lite.
  73          */
  74         __u16            pcslen;
  75         __u16            pcrlen;
  76         /*
  77          * For encapsulation sockets.
  78          */
  79         int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
  80         void (*encap_err_rcv)(struct sock *sk, struct sk_buff *skb, int err,
  81                               __be16 port, u32 info, u8 *payload);
  82         int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
  83         void (*encap_destroy)(struct sock *sk);
  84
  85         /* GRO functions for UDP socket */
  86         struct sk_buff *        (*gro_receive)(struct sock *sk,
  87                                                struct list_head *head,
  88                                                struct sk_buff *skb);
  89         int                     (*gro_complete)(struct sock *sk,
  90                                                 struct sk_buff *skb,
  91                                                 int nhoff);
  92
  93         /* udp_recvmsg try to use this before splicing sk_receive_queue */
  94         struct sk_buff_head     reader_queue ____cacheline_aligned_in_smp;
  95
  96         /* This field is dirtied by udp_recvmsg() */
  97         int             forward_deficit;
  98
  99         /* This fields follows rcvbuf value, and is touched by udp_recvmsg */
 100         int             forward_threshold;
 101
 102         /* Cache friendly copy of sk->sk_peek_off >= 0 */
 103         bool            peeking_with_offset;
 104 };
 105
 106 #define udp_test_bit(nr, sk)                    \
 107         test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
 108 #define udp_set_bit(nr, sk)                     \
 109         set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
 110 #define udp_test_and_set_bit(nr, sk)            \
 111         test_and_set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
 112 #define udp_clear_bit(nr, sk)                   \
 113         clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
 114 #define udp_assign_bit(nr, sk, val)             \
 115         assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val)
 116
 117 #define UDP_MAX_SEGMENTS        (1 << 7UL)
 118
 119 #define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk)
 120
 121 static inline int udp_set_peek_off(struct sock *sk, int val)
 122 {
 123         sk_set_peek_off(sk, val);
 124         WRITE_ONCE(udp_sk(sk)->peeking_with_offset, val >= 0);
 125         return 0;
 126 }
 127
 128 static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
 129 {
 130         udp_assign_bit(NO_CHECK6_TX, sk, val);
 131 }
 132
 133 static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
 134 {
 135         udp_assign_bit(NO_CHECK6_RX, sk, val);
 136 }
 137
 138 static inline bool udp_get_no_check6_tx(const struct sock *sk)
 139 {
 140         return udp_test_bit(NO_CHECK6_TX, sk);
 141 }
 142
 143 static inline bool udp_get_no_check6_rx(const struct sock *sk)
 144 {
 145         return udp_test_bit(NO_CHECK6_RX, sk);
 146 }
 147
 148 static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
 149                                  struct sk_buff *skb)
 150 {
 151         int gso_size;
 152
 153         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
 154                 gso_size = skb_shinfo(skb)->gso_size;
 155                 put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
 156         }
 157 }
 158
 159 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
 160 #if IS_ENABLED(CONFIG_IPV6)
 161 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
 162 #endif
 163
 164 static inline bool udp_encap_needed(void)
 165 {
 166         if (static_branch_unlikely(&udp_encap_needed_key))
 167                 return true;
 168
 169 #if IS_ENABLED(CONFIG_IPV6)
 170         if (static_branch_unlikely(&udpv6_encap_needed_key))
 171                 return true;
 172 #endif
 173
 174         return false;
 175 }
 176
 177 static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
 178 {
 179         if (!skb_is_gso(skb))
 180                 return false;
 181
 182         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
 183             !udp_test_bit(ACCEPT_L4, sk))
 184                 return true;
 185
 186         if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST &&
 187             !udp_test_bit(ACCEPT_FRAGLIST, sk))
 188                 return true;
 189
 190         /* GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits might still
 191          * land in a tunnel as the socket check in udp_gro_receive cannot be
 192          * foolproof.
 193          */
 194         if (udp_encap_needed() &&
 195             READ_ONCE(udp_sk(sk)->encap_rcv) &&
 196             !(skb_shinfo(skb)->gso_type &
 197               (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)))
 198                 return true;
 199
 200         return false;
 201 }
 202
 203 static inline void udp_allow_gso(struct sock *sk)
 204 {
 205         udp_set_bit(ACCEPT_L4, sk);
 206         udp_set_bit(ACCEPT_FRAGLIST, sk);
 207 }
 208
 209 #define udp_portaddr_for_each_entry(__sk, list) \
 210         hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
 211
 212 #define udp_portaddr_for_each_entry_rcu(__sk, list) \
 213         hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
 214
 215 #if !IS_ENABLED(CONFIG_BASE_SMALL)
 216 #define udp_lrpa_for_each_entry_rcu(__up, node, list) \
 217         hlist_nulls_for_each_entry_rcu(__up, node, list, udp_lrpa_node)
 218 #endif
 219
 220 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
 221
 222 #endif  /* _LINUX_UDP_H */