1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Definitions for the UDP module. 7 * 8 * Version: @(#)udp.h 1.0.2 05/07/93 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * 13 * Fixes: 14 * Alan Cox : Turned on udp checksums. I don't want to 15 * chase 'memory corruption' bugs that aren't! 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License 19 * as published by the Free Software Foundation; either version 20 * 2 of the License, or (at your option) any later version. 21 */ 22 #ifndef _UDP_H 23 #define _UDP_H 24 25 #include <linux/list.h> 26 #include <linux/bug.h> 27 #include <net/inet_sock.h> 28 #include <net/sock.h> 29 #include <net/snmp.h> 30 #include <net/ip.h> 31 #include <linux/ipv6.h> 32 #include <linux/seq_file.h> 33 #include <linux/poll.h> 34 35 /** 36 * struct udp_skb_cb - UDP(-Lite) private variables 37 * 38 * @header: private variables used by IPv4/IPv6 39 * @cscov: checksum coverage length (UDP-Lite only) 40 * @partial_cov: if set indicates partial csum coverage 41 */ 42 struct udp_skb_cb { 43 union { 44 struct inet_skb_parm h4; 45 #if IS_ENABLED(CONFIG_IPV6) 46 struct inet6_skb_parm h6; 47 #endif 48 } header; 49 __u16 cscov; 50 __u8 partial_cov; 51 }; 52 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) 53 54 /** 55 * struct udp_hslot - UDP hash slot 56 * 57 * @head: head of list of sockets 58 * @count: number of sockets in 'head' list 59 * @lock: spinlock protecting changes to head/count 60 */ 61 struct udp_hslot { 62 struct hlist_nulls_head head; 63 int count; 64 spinlock_t lock; 65 } __attribute__((aligned(2 * sizeof(long)))); 66 67 /** 68 * struct udp_table - UDP table 69 * 70 * @hash: hash table, sockets are hashed on (local port) 71 * @hash2: hash table, sockets are hashed on (local port, local address) 72 * @mask: number of slots in hash tables, minus 1 73 * @log: log2(number of slots in hash table) 74 */ 75 struct udp_table { 76 struct udp_hslot *hash; 77 struct udp_hslot *hash2; 78 unsigned int mask; 79 unsigned int log; 80 }; 81 extern struct udp_table udp_table; 82 void udp_table_init(struct udp_table *, const char *); 83 static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 84 struct net *net, unsigned int num) 85 { 86 return &table->hash[udp_hashfn(net, num, table->mask)]; 87 } 88 /* 89 * For secondary hash, net_hash_mix() is performed before calling 90 * udp_hashslot2(), this explains difference with udp_hashslot() 91 */ 92 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 93 unsigned int hash) 94 { 95 return &table->hash2[hash & table->mask]; 96 } 97 98 extern struct proto udp_prot; 99 100 extern atomic_long_t udp_memory_allocated; 101 102 /* sysctl variables for udp */ 103 extern long sysctl_udp_mem[3]; 104 extern int sysctl_udp_rmem_min; 105 extern int sysctl_udp_wmem_min; 106 107 struct sk_buff; 108 109 /* 110 * Generic checksumming routines for UDP(-Lite) v4 and v6 111 */ 112 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb) 113 { 114 return (UDP_SKB_CB(skb)->cscov == skb->len ? 115 __skb_checksum_complete(skb) : 116 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov)); 117 } 118 119 static inline int udp_lib_checksum_complete(struct sk_buff *skb) 120 { 121 return !skb_csum_unnecessary(skb) && 122 __udp_lib_checksum_complete(skb); 123 } 124 125 /** 126 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments 127 * @sk: socket we are writing to 128 * @skb: sk_buff containing the filled-in UDP header 129 * (checksum field must be zeroed out) 130 */ 131 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb) 132 { 133 __wsum csum = csum_partial(skb_transport_header(skb), 134 sizeof(struct udphdr), 0); 135 skb_queue_walk(&sk->sk_write_queue, skb) { 136 csum = csum_add(csum, skb->csum); 137 } 138 return csum; 139 } 140 141 static inline __wsum udp_csum(struct sk_buff *skb) 142 { 143 __wsum csum = csum_partial(skb_transport_header(skb), 144 sizeof(struct udphdr), skb->csum); 145 146 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) { 147 csum = csum_add(csum, skb->csum); 148 } 149 return csum; 150 } 151 152 static inline __sum16 udp_v4_check(int len, __be32 saddr, 153 __be32 daddr, __wsum base) 154 { 155 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base); 156 } 157 158 void udp_set_csum(bool nocheck, struct sk_buff *skb, 159 __be32 saddr, __be32 daddr, int len); 160 161 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb, 162 struct udphdr *uh); 163 int udp_gro_complete(struct sk_buff *skb, int nhoff); 164 165 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 166 { 167 struct udphdr *uh; 168 unsigned int hlen, off; 169 170 off = skb_gro_offset(skb); 171 hlen = off + sizeof(*uh); 172 uh = skb_gro_header_fast(skb, off); 173 if (skb_gro_header_hard(skb, hlen)) 174 uh = skb_gro_header_slow(skb, hlen, off); 175 176 return uh; 177 } 178 179 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 180 static inline void udp_lib_hash(struct sock *sk) 181 { 182 BUG(); 183 } 184 185 void udp_lib_unhash(struct sock *sk); 186 void udp_lib_rehash(struct sock *sk, u16 new_hash); 187 188 static inline void udp_lib_close(struct sock *sk, long timeout) 189 { 190 sk_common_release(sk); 191 } 192 193 int udp_lib_get_port(struct sock *sk, unsigned short snum, 194 int (*)(const struct sock *, const struct sock *), 195 unsigned int hash2_nulladdr); 196 197 u32 udp_flow_hashrnd(void); 198 199 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 200 int min, int max, bool use_eth) 201 { 202 u32 hash; 203 204 if (min >= max) { 205 /* Use default range */ 206 inet_get_local_port_range(net, &min, &max); 207 } 208 209 hash = skb_get_hash(skb); 210 if (unlikely(!hash)) { 211 if (use_eth) { 212 /* Can't find a normal hash, caller has indicated an 213 * Ethernet packet so use that to compute a hash. 214 */ 215 hash = jhash(skb->data, 2 * ETH_ALEN, 216 (__force u32) skb->protocol); 217 } else { 218 /* Can't derive any sort of hash for the packet, set 219 * to some consistent random value. 220 */ 221 hash = udp_flow_hashrnd(); 222 } 223 } 224 225 /* Since this is being sent on the wire obfuscate hash a bit 226 * to minimize possbility that any useful information to an 227 * attacker is leaked. Only upper 16 bits are relevant in the 228 * computation for 16 bit port value. 229 */ 230 hash ^= hash << 16; 231 232 return htons((((u64) hash * (max - min)) >> 32) + min); 233 } 234 235 /* net/ipv4/udp.c */ 236 void udp_v4_early_demux(struct sk_buff *skb); 237 int udp_get_port(struct sock *sk, unsigned short snum, 238 int (*saddr_cmp)(const struct sock *, 239 const struct sock *)); 240 void udp_err(struct sk_buff *, u32); 241 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 242 int udp_push_pending_frames(struct sock *sk); 243 void udp_flush_pending_frames(struct sock *sk); 244 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 245 int udp_rcv(struct sk_buff *skb); 246 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 247 int udp_disconnect(struct sock *sk, int flags); 248 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait); 249 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 250 netdev_features_t features, 251 bool is_ipv6); 252 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 253 char __user *optval, int __user *optlen); 254 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 255 char __user *optval, unsigned int optlen, 256 int (*push_pending_frames)(struct sock *)); 257 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 258 __be32 daddr, __be16 dport, int dif); 259 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 260 __be32 daddr, __be16 dport, int dif, 261 struct udp_table *tbl); 262 struct sock *udp6_lib_lookup(struct net *net, 263 const struct in6_addr *saddr, __be16 sport, 264 const struct in6_addr *daddr, __be16 dport, 265 int dif); 266 struct sock *__udp6_lib_lookup(struct net *net, 267 const struct in6_addr *saddr, __be16 sport, 268 const struct in6_addr *daddr, __be16 dport, 269 int dif, struct udp_table *tbl); 270 271 /* 272 * SNMP statistics for UDP and UDP-Lite 273 */ 274 #define UDP_INC_STATS_USER(net, field, is_udplite) do { \ 275 if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field); \ 276 else SNMP_INC_STATS_USER((net)->mib.udp_statistics, field); } while(0) 277 #define UDP_INC_STATS_BH(net, field, is_udplite) do { \ 278 if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field); \ 279 else SNMP_INC_STATS_BH((net)->mib.udp_statistics, field); } while(0) 280 281 #define UDP6_INC_STATS_BH(net, field, is_udplite) do { \ 282 if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\ 283 else SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field); \ 284 } while(0) 285 #define UDP6_INC_STATS_USER(net, field, __lite) do { \ 286 if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field); \ 287 else SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field); \ 288 } while(0) 289 290 #if IS_ENABLED(CONFIG_IPV6) 291 #define UDPX_INC_STATS_BH(sk, field) \ 292 do { \ 293 if ((sk)->sk_family == AF_INET) \ 294 UDP_INC_STATS_BH(sock_net(sk), field, 0); \ 295 else \ 296 UDP6_INC_STATS_BH(sock_net(sk), field, 0); \ 297 } while (0) 298 #else 299 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0) 300 #endif 301 302 /* /proc */ 303 int udp_seq_open(struct inode *inode, struct file *file); 304 305 struct udp_seq_afinfo { 306 char *name; 307 sa_family_t family; 308 struct udp_table *udp_table; 309 const struct file_operations *seq_fops; 310 struct seq_operations seq_ops; 311 }; 312 313 struct udp_iter_state { 314 struct seq_net_private p; 315 sa_family_t family; 316 int bucket; 317 struct udp_table *udp_table; 318 }; 319 320 #ifdef CONFIG_PROC_FS 321 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo); 322 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo); 323 324 int udp4_proc_init(void); 325 void udp4_proc_exit(void); 326 #endif 327 328 int udpv4_offload_init(void); 329 330 void udp_init(void); 331 332 void udp_encap_enable(void); 333 #if IS_ENABLED(CONFIG_IPV6) 334 void udpv6_encap_enable(void); 335 #endif 336 #endif /* _UDP_H */ 337