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 #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 * Accounting for the tunnel GRO fastpath. 107 * Unprotected by compilers guard, as it uses space available in 108 * the last UDP socket cacheline. 109 */ 110 struct hlist_node tunnel_list; 111 }; 112 113 #define udp_test_bit(nr, sk) \ 114 test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags) 115 #define udp_set_bit(nr, sk) \ 116 set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags) 117 #define udp_test_and_set_bit(nr, sk) \ 118 test_and_set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags) 119 #define udp_clear_bit(nr, sk) \ 120 clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags) 121 #define udp_assign_bit(nr, sk, val) \ 122 assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val) 123 124 #define UDP_MAX_SEGMENTS (1 << 7UL) 125 126 #define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk) 127 128 static inline int udp_set_peek_off(struct sock *sk, int val) 129 { 130 sk_set_peek_off(sk, val); 131 WRITE_ONCE(udp_sk(sk)->peeking_with_offset, val >= 0); 132 return 0; 133 } 134 135 static inline void udp_set_no_check6_tx(struct sock *sk, bool val) 136 { 137 udp_assign_bit(NO_CHECK6_TX, sk, val); 138 } 139 140 static inline void udp_set_no_check6_rx(struct sock *sk, bool val) 141 { 142 udp_assign_bit(NO_CHECK6_RX, sk, val); 143 } 144 145 static inline bool udp_get_no_check6_tx(const struct sock *sk) 146 { 147 return udp_test_bit(NO_CHECK6_TX, sk); 148 } 149 150 static inline bool udp_get_no_check6_rx(const struct sock *sk) 151 { 152 return udp_test_bit(NO_CHECK6_RX, sk); 153 } 154 155 static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk, 156 struct sk_buff *skb) 157 { 158 int gso_size; 159 160 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) { 161 gso_size = skb_shinfo(skb)->gso_size; 162 put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size); 163 } 164 } 165 166 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 167 #if IS_ENABLED(CONFIG_IPV6) 168 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 169 #endif 170 171 static inline bool udp_encap_needed(void) 172 { 173 if (static_branch_unlikely(&udp_encap_needed_key)) 174 return true; 175 176 #if IS_ENABLED(CONFIG_IPV6) 177 if (static_branch_unlikely(&udpv6_encap_needed_key)) 178 return true; 179 #endif 180 181 return false; 182 } 183 184 static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb) 185 { 186 if (!skb_is_gso(skb)) 187 return false; 188 189 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && 190 !udp_test_bit(ACCEPT_L4, sk)) 191 return true; 192 193 if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST && 194 !udp_test_bit(ACCEPT_FRAGLIST, sk)) 195 return true; 196 197 /* GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits might still 198 * land in a tunnel as the socket check in udp_gro_receive cannot be 199 * foolproof. 200 */ 201 if (udp_encap_needed() && 202 READ_ONCE(udp_sk(sk)->encap_rcv) && 203 !(skb_shinfo(skb)->gso_type & 204 (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM))) 205 return true; 206 207 return false; 208 } 209 210 static inline void udp_allow_gso(struct sock *sk) 211 { 212 udp_set_bit(ACCEPT_L4, sk); 213 udp_set_bit(ACCEPT_FRAGLIST, sk); 214 } 215 216 #define udp_portaddr_for_each_entry(__sk, list) \ 217 hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node) 218 219 #define udp_portaddr_for_each_entry_from(__sk) \ 220 hlist_for_each_entry_from(__sk, __sk_common.skc_portaddr_node) 221 222 #define udp_portaddr_for_each_entry_rcu(__sk, list) \ 223 hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node) 224 225 #if !IS_ENABLED(CONFIG_BASE_SMALL) 226 #define udp_lrpa_for_each_entry_rcu(__up, node, list) \ 227 hlist_nulls_for_each_entry_rcu(__up, node, list, udp_lrpa_node) 228 #endif 229 230 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE) 231 232 static inline struct sock *udp_tunnel_sk(const struct net *net, bool is_ipv6) 233 { 234 #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) 235 return rcu_dereference(net->ipv4.udp_tunnel_gro[is_ipv6].sk); 236 #else 237 return NULL; 238 #endif 239 } 240 241 #endif /* _LINUX_UDP_H */ 242