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 static inline struct udphdr *inner_udp_hdr(const struct sk_buff *skb)
  27 {
  28         return (struct udphdr *)skb_inner_transport_header(skb);
  29 }
  30
  31 #define UDP_HTABLE_SIZE_MIN             (CONFIG_BASE_SMALL ? 128 : 256)
  32
  33 static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
  34 {
  35         return (num + net_hash_mix(net)) & mask;
  36 }
  37
  38 struct udp_sock {
  39         /* inet_sock has to be the first member */
  40         struct inet_sock inet;
  41 #define udp_port_hash           inet.sk.__sk_common.skc_u16hashes[0]
  42 #define udp_portaddr_hash       inet.sk.__sk_common.skc_u16hashes[1]
  43 #define udp_portaddr_node       inet.sk.__sk_common.skc_portaddr_node
  44         int              pending;       /* Any pending frames ? */
  45         unsigned int     corkflag;      /* Cork is required */
  46         __u8             encap_type;    /* Is this an Encapsulation socket? */
  47         unsigned char    no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
  48                          no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
  49                          encap_enabled:1, /* This socket enabled encap
  50                                            * processing; UDP tunnels and
  51                                            * different encapsulation layer set
  52                                            * this
  53                                            */
  54                          gro_enabled:1, /* Request GRO aggregation */
  55                          accept_udp_l4:1,
  56                          accept_udp_fraglist:1;
  57         /*
  58          * Following member retains the information to create a UDP header
  59          * when the socket is uncorked.
  60          */
  61         __u16            len;           /* total length of pending frames */
  62         __u16            gso_size;
  63         /*
  64          * Fields specific to UDP-Lite.
  65          */
  66         __u16            pcslen;
  67         __u16            pcrlen;
  68 /* indicator bits used by pcflag: */
  69 #define UDPLITE_BIT      0x1            /* set by udplite proto init function */
  70 #define UDPLITE_SEND_CC  0x2            /* set via udplite setsockopt         */
  71 #define UDPLITE_RECV_CC  0x4            /* set via udplite setsocktopt        */
  72         __u8             pcflag;        /* marks socket as UDP-Lite if > 0    */
  73         __u8             unused[3];
  74         /*
  75          * For encapsulation sockets.
  76          */
  77         int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
  78         int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
  79         void (*encap_destroy)(struct sock *sk);
  80
  81         /* GRO functions for UDP socket */
  82         struct sk_buff *        (*gro_receive)(struct sock *sk,
  83                                                struct list_head *head,
  84                                                struct sk_buff *skb);
  85         int                     (*gro_complete)(struct sock *sk,
  86                                                 struct sk_buff *skb,
  87                                                 int nhoff);
  88
  89         /* udp_recvmsg try to use this before splicing sk_receive_queue */
  90         struct sk_buff_head     reader_queue ____cacheline_aligned_in_smp;
  91
  92         /* This field is dirtied by udp_recvmsg() */
  93         int             forward_deficit;
  94 };
  95
  96 #define UDP_MAX_SEGMENTS        (1 << 6UL)
  97
  98 static inline struct udp_sock *udp_sk(const struct sock *sk)
  99 {
 100         return (struct udp_sock *)sk;
 101 }
 102
 103 static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
 104 {
 105         udp_sk(sk)->no_check6_tx = val;
 106 }
 107
 108 static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
 109 {
 110         udp_sk(sk)->no_check6_rx = val;
 111 }
 112
 113 static inline bool udp_get_no_check6_tx(struct sock *sk)
 114 {
 115         return udp_sk(sk)->no_check6_tx;
 116 }
 117
 118 static inline bool udp_get_no_check6_rx(struct sock *sk)
 119 {
 120         return udp_sk(sk)->no_check6_rx;
 121 }
 122
 123 static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
 124                                  struct sk_buff *skb)
 125 {
 126         int gso_size;
 127
 128         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
 129                 gso_size = skb_shinfo(skb)->gso_size;
 130                 put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
 131         }
 132 }
 133
 134 static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
 135 {
 136         if (!skb_is_gso(skb))
 137                 return false;
 138
 139         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && !udp_sk(sk)->accept_udp_l4)
 140                 return true;
 141
 142         if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST && !udp_sk(sk)->accept_udp_fraglist)
 143                 return true;
 144
 145         return false;
 146 }
 147
 148 static inline void udp_allow_gso(struct sock *sk)
 149 {
 150         udp_sk(sk)->accept_udp_l4 = 1;
 151         udp_sk(sk)->accept_udp_fraglist = 1;
 152 }
 153
 154 #define udp_portaddr_for_each_entry(__sk, list) \
 155         hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
 156
 157 #define udp_portaddr_for_each_entry_rcu(__sk, list) \
 158         hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
 159
 160 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
 161
 162 #endif  /* _LINUX_UDP_H */