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 #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
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
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
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
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
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
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
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
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
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
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
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