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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
21static 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
30static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
31{
32 return (num + net_hash_mix(net)) & mask;
33}
34
35enum {
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
47struct 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
121static 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
128static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
129{
130 udp_assign_bit(NO_CHECK6_TX, sk, val);
131}
132
133static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
134{
135 udp_assign_bit(NO_CHECK6_RX, sk, val);
136}
137
138static inline bool udp_get_no_check6_tx(const struct sock *sk)
139{
140 return udp_test_bit(NO_CHECK6_TX, sk);
141}
142
143static inline bool udp_get_no_check6_rx(const struct sock *sk)
144{
145 return udp_test_bit(NO_CHECK6_RX, sk);
146}
147
148static 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
159DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
160#if IS_ENABLED(CONFIG_IPV6)
161DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
162#endif
163
164static 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
177static 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
203static 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 */