xref: /linux/include/linux/udp.h (revision 1f6154227b49c3d3f306f624858e695bfee50aae)
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 #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 
udp_set_peek_off(struct sock * sk,int val)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 
udp_set_no_check6_tx(struct sock * sk,bool val)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 
udp_set_no_check6_rx(struct sock * sk,bool val)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 
udp_get_no_check6_tx(const struct sock * sk)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 
udp_get_no_check6_rx(const struct sock * sk)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 
udp_cmsg_recv(struct msghdr * msg,struct sock * sk,struct sk_buff * skb)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 
udp_encap_needed(void)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 
udp_unexpected_gso(struct sock * sk,struct sk_buff * skb)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 
udp_allow_gso(struct sock * sk)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 */
223