xref: /openbmc/linux/include/linux/udp.h (revision c845428b7a9157523103100806bc8130d64769c8)
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  
udp_hdr(const struct sk_buff * skb)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		(CONFIG_BASE_SMALL ? 128 : 256)
28  #define UDP_HTABLE_SIZE_MAX		65536
29  
udp_hashfn(const struct net * net,u32 num,u32 mask)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  	/*
60  	 * Following member retains the information to create a UDP header
61  	 * when the socket is uncorked.
62  	 */
63  	__u16		 len;		/* total length of pending frames */
64  	__u16		 gso_size;
65  	/*
66  	 * Fields specific to UDP-Lite.
67  	 */
68  	__u16		 pcslen;
69  	__u16		 pcrlen;
70  	/*
71  	 * For encapsulation sockets.
72  	 */
73  	int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
74  	void (*encap_err_rcv)(struct sock *sk, struct sk_buff *skb, int err,
75  			      __be16 port, u32 info, u8 *payload);
76  	int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
77  	void (*encap_destroy)(struct sock *sk);
78  
79  	/* GRO functions for UDP socket */
80  	struct sk_buff *	(*gro_receive)(struct sock *sk,
81  					       struct list_head *head,
82  					       struct sk_buff *skb);
83  	int			(*gro_complete)(struct sock *sk,
84  						struct sk_buff *skb,
85  						int nhoff);
86  
87  	/* udp_recvmsg try to use this before splicing sk_receive_queue */
88  	struct sk_buff_head	reader_queue ____cacheline_aligned_in_smp;
89  
90  	/* This field is dirtied by udp_recvmsg() */
91  	int		forward_deficit;
92  
93  	/* This fields follows rcvbuf value, and is touched by udp_recvmsg */
94  	int		forward_threshold;
95  };
96  
97  #define udp_test_bit(nr, sk)			\
98  	test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
99  #define udp_set_bit(nr, sk)			\
100  	set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
101  #define udp_test_and_set_bit(nr, sk)		\
102  	test_and_set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
103  #define udp_clear_bit(nr, sk)			\
104  	clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
105  #define udp_assign_bit(nr, sk, val)		\
106  	assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val)
107  
108  #define UDP_MAX_SEGMENTS	(1 << 7UL)
109  
110  #define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk)
111  
udp_set_no_check6_tx(struct sock * sk,bool val)112  static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
113  {
114  	udp_assign_bit(NO_CHECK6_TX, sk, val);
115  }
116  
udp_set_no_check6_rx(struct sock * sk,bool val)117  static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
118  {
119  	udp_assign_bit(NO_CHECK6_RX, sk, val);
120  }
121  
udp_get_no_check6_tx(const struct sock * sk)122  static inline bool udp_get_no_check6_tx(const struct sock *sk)
123  {
124  	return udp_test_bit(NO_CHECK6_TX, sk);
125  }
126  
udp_get_no_check6_rx(const struct sock * sk)127  static inline bool udp_get_no_check6_rx(const struct sock *sk)
128  {
129  	return udp_test_bit(NO_CHECK6_RX, sk);
130  }
131  
udp_cmsg_recv(struct msghdr * msg,struct sock * sk,struct sk_buff * skb)132  static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
133  				 struct sk_buff *skb)
134  {
135  	int gso_size;
136  
137  	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
138  		gso_size = skb_shinfo(skb)->gso_size;
139  		put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
140  	}
141  }
142  
143  DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
144  #if IS_ENABLED(CONFIG_IPV6)
145  DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
146  #endif
147  
udp_encap_needed(void)148  static inline bool udp_encap_needed(void)
149  {
150  	if (static_branch_unlikely(&udp_encap_needed_key))
151  		return true;
152  
153  #if IS_ENABLED(CONFIG_IPV6)
154  	if (static_branch_unlikely(&udpv6_encap_needed_key))
155  		return true;
156  #endif
157  
158  	return false;
159  }
160  
udp_unexpected_gso(struct sock * sk,struct sk_buff * skb)161  static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
162  {
163  	if (!skb_is_gso(skb))
164  		return false;
165  
166  	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
167  	    !udp_test_bit(ACCEPT_L4, sk))
168  		return true;
169  
170  	if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST &&
171  	    !udp_test_bit(ACCEPT_FRAGLIST, sk))
172  		return true;
173  
174  	/* GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits might still
175  	 * land in a tunnel as the socket check in udp_gro_receive cannot be
176  	 * foolproof.
177  	 */
178  	if (udp_encap_needed() &&
179  	    READ_ONCE(udp_sk(sk)->encap_rcv) &&
180  	    !(skb_shinfo(skb)->gso_type &
181  	      (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)))
182  		return true;
183  
184  	return false;
185  }
186  
udp_allow_gso(struct sock * sk)187  static inline void udp_allow_gso(struct sock *sk)
188  {
189  	udp_set_bit(ACCEPT_L4, sk);
190  	udp_set_bit(ACCEPT_FRAGLIST, sk);
191  }
192  
193  #define udp_portaddr_for_each_entry(__sk, list) \
194  	hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
195  
196  #define udp_portaddr_for_each_entry_rcu(__sk, list) \
197  	hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
198  
199  #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
200  
201  #endif	/* _LINUX_UDP_H */
202