xref: /linux/include/linux/udp.h (revision a19264d0868dfd65d7222b37ffe41068b53d473a)
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		(IS_ENABLED(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 	/* Cache friendly copy of sk->sk_peek_off >= 0 */
97 	bool		peeking_with_offset;
98 };
99 
100 #define udp_test_bit(nr, sk)			\
101 	test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
102 #define udp_set_bit(nr, sk)			\
103 	set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
104 #define udp_test_and_set_bit(nr, sk)		\
105 	test_and_set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
106 #define udp_clear_bit(nr, sk)			\
107 	clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
108 #define udp_assign_bit(nr, sk, val)		\
109 	assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val)
110 
111 #define UDP_MAX_SEGMENTS	(1 << 7UL)
112 
113 #define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk)
114 
udp_set_peek_off(struct sock * sk,int val)115 static inline int udp_set_peek_off(struct sock *sk, int val)
116 {
117 	sk_set_peek_off(sk, val);
118 	WRITE_ONCE(udp_sk(sk)->peeking_with_offset, val >= 0);
119 	return 0;
120 }
121 
udp_set_no_check6_tx(struct sock * sk,bool val)122 static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
123 {
124 	udp_assign_bit(NO_CHECK6_TX, sk, val);
125 }
126 
udp_set_no_check6_rx(struct sock * sk,bool val)127 static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
128 {
129 	udp_assign_bit(NO_CHECK6_RX, sk, val);
130 }
131 
udp_get_no_check6_tx(const struct sock * sk)132 static inline bool udp_get_no_check6_tx(const struct sock *sk)
133 {
134 	return udp_test_bit(NO_CHECK6_TX, sk);
135 }
136 
udp_get_no_check6_rx(const struct sock * sk)137 static inline bool udp_get_no_check6_rx(const struct sock *sk)
138 {
139 	return udp_test_bit(NO_CHECK6_RX, sk);
140 }
141 
udp_cmsg_recv(struct msghdr * msg,struct sock * sk,struct sk_buff * skb)142 static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
143 				 struct sk_buff *skb)
144 {
145 	int gso_size;
146 
147 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
148 		gso_size = skb_shinfo(skb)->gso_size;
149 		put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
150 	}
151 }
152 
153 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
154 #if IS_ENABLED(CONFIG_IPV6)
155 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
156 #endif
157 
udp_encap_needed(void)158 static inline bool udp_encap_needed(void)
159 {
160 	if (static_branch_unlikely(&udp_encap_needed_key))
161 		return true;
162 
163 #if IS_ENABLED(CONFIG_IPV6)
164 	if (static_branch_unlikely(&udpv6_encap_needed_key))
165 		return true;
166 #endif
167 
168 	return false;
169 }
170 
udp_unexpected_gso(struct sock * sk,struct sk_buff * skb)171 static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
172 {
173 	if (!skb_is_gso(skb))
174 		return false;
175 
176 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
177 	    !udp_test_bit(ACCEPT_L4, sk))
178 		return true;
179 
180 	if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST &&
181 	    !udp_test_bit(ACCEPT_FRAGLIST, sk))
182 		return true;
183 
184 	/* GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits might still
185 	 * land in a tunnel as the socket check in udp_gro_receive cannot be
186 	 * foolproof.
187 	 */
188 	if (udp_encap_needed() &&
189 	    READ_ONCE(udp_sk(sk)->encap_rcv) &&
190 	    !(skb_shinfo(skb)->gso_type &
191 	      (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)))
192 		return true;
193 
194 	return false;
195 }
196 
udp_allow_gso(struct sock * sk)197 static inline void udp_allow_gso(struct sock *sk)
198 {
199 	udp_set_bit(ACCEPT_L4, sk);
200 	udp_set_bit(ACCEPT_FRAGLIST, sk);
201 }
202 
203 #define udp_portaddr_for_each_entry(__sk, list) \
204 	hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
205 
206 #define udp_portaddr_for_each_entry_rcu(__sk, list) \
207 	hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
208 
209 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
210 
211 #endif	/* _LINUX_UDP_H */
212