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 module. 8 * 9 * Version: @(#)udp.h 1.0.2 05/07/93 10 * 11 * Authors: Ross Biro 12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 13 * 14 * Fixes: 15 * Alan Cox : Turned on udp checksums. I don't want to 16 * chase 'memory corruption' bugs that aren't! 17 */ 18 #ifndef _UDP_H 19 #define _UDP_H 20 21 #include <linux/list.h> 22 #include <linux/bug.h> 23 #include <net/inet_sock.h> 24 #include <net/gso.h> 25 #include <net/sock.h> 26 #include <net/snmp.h> 27 #include <net/ip.h> 28 #include <linux/ipv6.h> 29 #include <linux/seq_file.h> 30 #include <linux/poll.h> 31 #include <linux/indirect_call_wrapper.h> 32 #include <linux/math.h> 33 34 /** 35 * struct udp_skb_cb - UDP private variables 36 * 37 * @header: private variables used by IPv4/IPv6 38 */ 39 struct udp_skb_cb { 40 union { 41 struct inet_skb_parm h4; 42 #if IS_ENABLED(CONFIG_IPV6) 43 struct inet6_skb_parm h6; 44 #endif 45 } header; 46 }; 47 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) 48 49 /** 50 * struct udp_hslot - UDP hash slot used by udp_table.hash/hash4 51 * 52 * @head: head of list of sockets 53 * @nulls_head: head of list of sockets, only used by hash4 54 * @count: number of sockets in 'head' list 55 * @lock: spinlock protecting changes to head/count 56 */ 57 struct udp_hslot { 58 union { 59 struct hlist_head head; 60 /* hash4 uses hlist_nulls to avoid moving wrongly onto another 61 * hlist, because rehash() can happen with lookup(). 62 */ 63 struct hlist_nulls_head nulls_head; 64 }; 65 int count; 66 spinlock_t lock; 67 } __aligned(2 * sizeof(long)); 68 69 /** 70 * struct udp_hslot_main - UDP hash slot used by udp_table.hash2 71 * 72 * @hslot: basic hash slot 73 * @hash4_cnt: number of sockets in hslot4 of the same 74 * (local port, local address) 75 */ 76 struct udp_hslot_main { 77 struct udp_hslot hslot; /* must be the first member */ 78 #if !IS_ENABLED(CONFIG_BASE_SMALL) 79 u32 hash4_cnt; 80 #endif 81 } __aligned(2 * sizeof(long)); 82 #define UDP_HSLOT_MAIN(__hslot) ((struct udp_hslot_main *)(__hslot)) 83 84 /** 85 * struct udp_table - UDP table 86 * 87 * @hash: hash table, sockets are hashed on (local port) 88 * @hash2: hash table, sockets are hashed on (local port, local address) 89 * @hash4: hash table, connected sockets are hashed on 90 * (local port, local address, remote port, remote address) 91 * @mask: number of slots in hash tables, minus 1 92 * @log: log2(number of slots in hash table) 93 */ 94 struct udp_table { 95 struct udp_hslot *hash; 96 struct udp_hslot_main *hash2; 97 #if !IS_ENABLED(CONFIG_BASE_SMALL) 98 struct udp_hslot *hash4; 99 #endif 100 unsigned int mask; 101 unsigned int log; 102 }; 103 extern struct udp_table udp_table; 104 105 static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 106 const struct net *net, 107 unsigned int num) 108 { 109 return &table->hash[udp_hashfn(net, num, table->mask)]; 110 } 111 112 /* 113 * For secondary hash, net_hash_mix() is performed before calling 114 * udp_hashslot2(), this explains difference with udp_hashslot() 115 */ 116 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 117 unsigned int hash) 118 { 119 return &table->hash2[hash & table->mask].hslot; 120 } 121 122 #if IS_ENABLED(CONFIG_BASE_SMALL) 123 static inline void udp_table_hash4_init(struct udp_table *table) 124 { 125 } 126 127 static inline struct udp_hslot *udp_hashslot4(struct udp_table *table, 128 unsigned int hash) 129 { 130 BUILD_BUG(); 131 return NULL; 132 } 133 134 static inline bool udp_hashed4(const struct sock *sk) 135 { 136 return false; 137 } 138 139 static inline unsigned int udp_hash4_slot_size(void) 140 { 141 return 0; 142 } 143 144 static inline bool udp_has_hash4(const struct udp_hslot *hslot2) 145 { 146 return false; 147 } 148 149 static inline void udp_hash4_inc(struct udp_hslot *hslot2) 150 { 151 } 152 153 static inline void udp_hash4_dec(struct udp_hslot *hslot2) 154 { 155 } 156 #else /* !CONFIG_BASE_SMALL */ 157 158 /* Must be called with table->hash2 initialized */ 159 static inline void udp_table_hash4_init(struct udp_table *table) 160 { 161 table->hash4 = (void *)(table->hash2 + (table->mask + 1)); 162 for (int i = 0; i <= table->mask; i++) { 163 table->hash2[i].hash4_cnt = 0; 164 165 INIT_HLIST_NULLS_HEAD(&table->hash4[i].nulls_head, i); 166 table->hash4[i].count = 0; 167 spin_lock_init(&table->hash4[i].lock); 168 } 169 } 170 171 static inline struct udp_hslot *udp_hashslot4(struct udp_table *table, 172 unsigned int hash) 173 { 174 return &table->hash4[hash & table->mask]; 175 } 176 177 static inline bool udp_hashed4(const struct sock *sk) 178 { 179 return !hlist_nulls_unhashed(&udp_sk(sk)->udp_lrpa_node); 180 } 181 182 static inline unsigned int udp_hash4_slot_size(void) 183 { 184 return sizeof(struct udp_hslot); 185 } 186 187 static inline bool udp_has_hash4(const struct udp_hslot *hslot2) 188 { 189 return UDP_HSLOT_MAIN(hslot2)->hash4_cnt; 190 } 191 192 static inline void udp_hash4_inc(struct udp_hslot *hslot2) 193 { 194 UDP_HSLOT_MAIN(hslot2)->hash4_cnt++; 195 } 196 197 static inline void udp_hash4_dec(struct udp_hslot *hslot2) 198 { 199 UDP_HSLOT_MAIN(hslot2)->hash4_cnt--; 200 } 201 #endif /* CONFIG_BASE_SMALL */ 202 203 extern struct proto udp_prot; 204 205 DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc); 206 207 /* sysctl variables for udp */ 208 extern long sysctl_udp_mem[3]; 209 extern int sysctl_udp_rmem_min; 210 extern int sysctl_udp_wmem_min; 211 212 struct sk_buff; 213 214 /* 215 * Generic checksumming routines for UDP v4 and v6 216 */ 217 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb) 218 { 219 return __skb_checksum_complete(skb); 220 } 221 222 static inline int udp_lib_checksum_complete(struct sk_buff *skb) 223 { 224 return !skb_csum_unnecessary(skb) && 225 __udp_lib_checksum_complete(skb); 226 } 227 228 /** 229 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments 230 * @sk: socket we are writing to 231 * @skb: sk_buff containing the filled-in UDP header 232 * (checksum field must be zeroed out) 233 */ 234 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb) 235 { 236 __wsum csum = csum_partial(skb_transport_header(skb), 237 sizeof(struct udphdr), 0); 238 skb_queue_walk(&sk->sk_write_queue, skb) { 239 csum = csum_add(csum, skb->csum); 240 } 241 return csum; 242 } 243 244 static inline __wsum udp_csum(struct sk_buff *skb) 245 { 246 __wsum csum = csum_partial(skb_transport_header(skb), 247 sizeof(struct udphdr), skb->csum); 248 249 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) { 250 csum = csum_add(csum, skb->csum); 251 } 252 return csum; 253 } 254 255 static inline __sum16 udp_v4_check(int len, __be32 saddr, 256 __be32 daddr, __wsum base) 257 { 258 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base); 259 } 260 261 void udp_set_csum(bool nocheck, struct sk_buff *skb, 262 __be32 saddr, __be32 daddr, int len); 263 264 static inline void udp_csum_pull_header(struct sk_buff *skb) 265 { 266 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE) 267 skb->csum = csum_partial(skb->data, sizeof(struct udphdr), 268 skb->csum); 269 skb_pull_rcsum(skb, sizeof(struct udphdr)); 270 } 271 272 typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport, 273 __be16 dport); 274 275 void udp_v6_early_demux(struct sk_buff *skb); 276 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *)); 277 278 int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 279 INDIRECT_CALLABLE_DECLARE(int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, 280 size_t len, int flags)); 281 282 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 283 netdev_features_t features, bool is_ipv6); 284 285 static inline int udp_lib_init_sock(struct sock *sk) 286 { 287 struct udp_sock *up = udp_sk(sk); 288 289 sk->sk_drop_counters = &up->drop_counters; 290 skb_queue_head_init(&up->reader_queue); 291 INIT_HLIST_NODE(&up->tunnel_list); 292 up->forward_threshold = sk->sk_rcvbuf >> 2; 293 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); 294 295 up->udp_prod_queue = kzalloc_objs(*up->udp_prod_queue, nr_node_ids); 296 if (!up->udp_prod_queue) 297 return -ENOMEM; 298 for (int i = 0; i < nr_node_ids; i++) 299 init_llist_head(&up->udp_prod_queue[i].ll_root); 300 return 0; 301 } 302 303 static inline void udp_drops_inc(struct sock *sk) 304 { 305 numa_drop_add(&udp_sk(sk)->drop_counters, 1); 306 } 307 308 /* hash routines shared between UDPv4/6 */ 309 static inline int udp_lib_hash(struct sock *sk) 310 { 311 BUG(); 312 return 0; 313 } 314 315 void udp_lib_unhash(struct sock *sk); 316 void udp_lib_rehash(struct sock *sk, u16 new_hash, u16 new_hash4); 317 u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport, 318 const __be32 faddr, const __be16 fport); 319 320 static inline void udp_lib_close(struct sock *sk, long timeout) 321 { 322 sk_common_release(sk); 323 } 324 325 /* hash4 routines shared between UDPv4/6 */ 326 #if IS_ENABLED(CONFIG_BASE_SMALL) 327 static inline void udp_lib_hash4(struct sock *sk, u16 hash) 328 { 329 } 330 331 static inline void udp4_hash4(struct sock *sk) 332 { 333 } 334 #else /* !CONFIG_BASE_SMALL */ 335 void udp_lib_hash4(struct sock *sk, u16 hash); 336 void udp4_hash4(struct sock *sk); 337 #endif /* CONFIG_BASE_SMALL */ 338 339 int udp_lib_get_port(struct sock *sk, unsigned short snum, 340 unsigned int hash2_nulladdr); 341 342 u32 udp_flow_hashrnd(void); 343 344 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 345 int min, int max, bool use_eth) 346 { 347 u32 hash; 348 349 if (min >= max) { 350 /* Use default range */ 351 inet_get_local_port_range(net, &min, &max); 352 } 353 354 hash = skb_get_hash(skb); 355 if (unlikely(!hash)) { 356 if (use_eth) { 357 /* Can't find a normal hash, caller has indicated an 358 * Ethernet packet so use that to compute a hash. 359 */ 360 hash = jhash(skb->data, 2 * ETH_ALEN, 361 (__force u32) skb->protocol); 362 } else { 363 /* Can't derive any sort of hash for the packet, set 364 * to some consistent random value. 365 */ 366 hash = udp_flow_hashrnd(); 367 } 368 } 369 370 /* Since this is being sent on the wire obfuscate hash a bit 371 * to minimize possibility that any useful information to an 372 * attacker is leaked. Only upper 16 bits are relevant in the 373 * computation for 16 bit port value. 374 */ 375 hash ^= hash << 16; 376 377 return htons(reciprocal_scale(hash, max - min + 1) + min); 378 } 379 380 static inline int udp_rqueue_get(struct sock *sk) 381 { 382 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 383 } 384 385 static inline bool udp_sk_bound_dev_eq(const struct net *net, int bound_dev_if, 386 int dif, int sdif) 387 { 388 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 389 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept), 390 bound_dev_if, dif, sdif); 391 #else 392 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 393 #endif 394 } 395 396 /* net/ipv4/udp.c */ 397 void udp_destruct_common(struct sock *sk); 398 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 399 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 400 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 401 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off, 402 int *err); 403 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 404 int *err) 405 { 406 int off = 0; 407 408 return __skb_recv_udp(sk, flags, &off, err); 409 } 410 411 enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb); 412 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 413 int udp_err(struct sk_buff *, u32); 414 int udp_abort(struct sock *sk, int err); 415 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 416 INDIRECT_CALLABLE_DECLARE(int udp_recvmsg(struct sock *sk, struct msghdr *msg, 417 size_t len, int flags)); 418 void udp_splice_eof(struct socket *sock); 419 int udp_push_pending_frames(struct sock *sk); 420 void udp_flush_pending_frames(struct sock *sk); 421 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 422 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 423 int udp_rcv(struct sk_buff *skb); 424 int udp_ioctl(struct sock *sk, int cmd, int *karg); 425 int udp_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len); 426 int __udp_disconnect(struct sock *sk, int flags); 427 int udp_disconnect(struct sock *sk, int flags); 428 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 429 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 430 netdev_features_t features, 431 bool is_ipv6); 432 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 433 char __user *optval, int __user *optlen); 434 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 435 sockptr_t optval, unsigned int optlen, 436 int (*push_pending_frames)(struct sock *)); 437 struct sock *udp4_lib_lookup(const struct net *net, __be32 saddr, __be16 sport, 438 __be32 daddr, __be16 dport, int dif); 439 struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr, 440 __be16 sport, __be32 daddr, __be16 dport, 441 int dif, int sdif, struct sk_buff *skb); 442 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, 443 __be16 sport, __be16 dport); 444 struct sock *udp6_lib_lookup(const struct net *net, 445 const struct in6_addr *saddr, __be16 sport, 446 const struct in6_addr *daddr, __be16 dport, 447 int dif); 448 struct sock *__udp6_lib_lookup(const struct net *net, 449 const struct in6_addr *saddr, __be16 sport, 450 const struct in6_addr *daddr, __be16 dport, 451 int dif, int sdif, struct sk_buff *skb); 452 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, 453 __be16 sport, __be16 dport); 454 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 455 456 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 457 * possibly multiple cache miss on dequeue() 458 */ 459 struct udp_dev_scratch { 460 /* skb->truesize and the stateless bit are embedded in a single field; 461 * do not use a bitfield since the compiler emits better/smaller code 462 * this way 463 */ 464 u32 _tsize_state; 465 466 #if BITS_PER_LONG == 64 467 /* len and the bit needed to compute skb_csum_unnecessary 468 * will be on cold cache lines at recvmsg time. 469 * skb->len can be stored on 16 bits since the udp header has been 470 * already validated and pulled. 471 */ 472 u16 len; 473 bool is_linear; 474 bool csum_unnecessary; 475 #endif 476 }; 477 478 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 479 { 480 return (struct udp_dev_scratch *)&skb->dev_scratch; 481 } 482 483 #if BITS_PER_LONG == 64 484 static inline unsigned int udp_skb_len(struct sk_buff *skb) 485 { 486 return udp_skb_scratch(skb)->len; 487 } 488 489 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 490 { 491 return udp_skb_scratch(skb)->csum_unnecessary; 492 } 493 494 static inline bool udp_skb_is_linear(struct sk_buff *skb) 495 { 496 return udp_skb_scratch(skb)->is_linear; 497 } 498 499 #else 500 static inline unsigned int udp_skb_len(struct sk_buff *skb) 501 { 502 return skb->len; 503 } 504 505 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 506 { 507 return skb_csum_unnecessary(skb); 508 } 509 510 static inline bool udp_skb_is_linear(struct sk_buff *skb) 511 { 512 return !skb_is_nonlinear(skb); 513 } 514 #endif 515 516 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 517 struct iov_iter *to) 518 { 519 return copy_to_iter_full(skb->data + off, len, to) ? 0 : -EFAULT; 520 } 521 522 /* 523 * SNMP statistics for UDP 524 */ 525 #define __UDP_INC_STATS(net, field) \ 526 __SNMP_INC_STATS((net)->mib.udp_statistics, field) 527 #define UDP_INC_STATS(net, field) \ 528 SNMP_INC_STATS((net)->mib.udp_statistics, field) 529 #define __UDP6_INC_STATS(net, field) \ 530 __SNMP_INC_STATS((net)->mib.udp_stats_in6, field) 531 #define UDP6_INC_STATS(net, field) \ 532 SNMP_INC_STATS((net)->mib.udp_stats_in6, field) 533 534 #if IS_ENABLED(CONFIG_IPV6) 535 #define __UDPX_MIB(sk, ipv4) \ 536 ({ \ 537 ipv4 ? sock_net(sk)->mib.udp_statistics : \ 538 sock_net(sk)->mib.udp_stats_in6; \ 539 }) 540 #else 541 #define __UDPX_MIB(sk, ipv4) \ 542 ({ \ 543 sock_net(sk)->mib.udp_statistics; \ 544 }) 545 #endif 546 547 #define __UDPX_INC_STATS(sk, field) \ 548 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 549 550 #ifdef CONFIG_PROC_FS 551 struct udp_seq_afinfo { 552 sa_family_t family; 553 }; 554 555 struct udp_iter_state { 556 struct seq_net_private p; 557 int bucket; 558 }; 559 560 void *udp_seq_start(struct seq_file *seq, loff_t *pos); 561 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 562 void udp_seq_stop(struct seq_file *seq, void *v); 563 564 int udp4_proc_init(void); 565 void udp4_proc_exit(void); 566 #endif /* CONFIG_PROC_FS */ 567 568 int udpv4_offload_init(void); 569 570 void udp_init(void); 571 572 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 573 void udp_encap_enable(void); 574 void udp_encap_disable(void); 575 #if IS_ENABLED(CONFIG_IPV6) 576 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 577 void udpv6_encap_enable(void); 578 #endif 579 580 static inline struct sk_buff *udp_rcv_segment(struct sock *sk, 581 struct sk_buff *skb, bool ipv4) 582 { 583 netdev_features_t features = NETIF_F_SG; 584 struct sk_buff *segs; 585 int drop_count; 586 587 /* 588 * Segmentation in UDP receive path is only for UDP GRO, drop udp 589 * fragmentation offload (UFO) packets. 590 */ 591 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) { 592 drop_count = 1; 593 goto drop; 594 } 595 596 /* Avoid csum recalculation by skb_segment unless userspace explicitly 597 * asks for the final checksum values 598 */ 599 if (!inet_get_convert_csum(sk)) 600 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; 601 602 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or 603 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial 604 * packets in udp_gro_complete_segment. As does UDP GSO, verified by 605 * udp_send_skb. But when those packets are looped in dev_loopback_xmit 606 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY. 607 * Reset in this specific case, where PARTIAL is both correct and 608 * required. 609 */ 610 if (skb->pkt_type == PACKET_LOOPBACK) 611 skb->ip_summed = CHECKSUM_PARTIAL; 612 613 /* the GSO CB lays after the UDP one, no need to save and restore any 614 * CB fragment 615 */ 616 segs = __skb_gso_segment(skb, features, false); 617 if (IS_ERR_OR_NULL(segs)) { 618 drop_count = skb_shinfo(skb)->gso_segs; 619 goto drop; 620 } 621 622 consume_skb(skb); 623 return segs; 624 625 drop: 626 sk_drops_add(sk, drop_count); 627 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, drop_count); 628 kfree_skb(skb); 629 return NULL; 630 } 631 632 static inline void udp_post_segment_fix_csum(struct sk_buff *skb) 633 { 634 /* UDP packets generated with UDP_SEGMENT and traversing: 635 * 636 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx) 637 * 638 * can reach an UDP socket with CHECKSUM_NONE, because 639 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE. 640 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will 641 * have a valid checksum, as the GRO engine validates the UDP csum 642 * before the aggregation and nobody strips such info in between. 643 * Instead of adding another check in the tunnel fastpath, we can force 644 * a valid csum after the segmentation. 645 * Additionally fixup the UDP CB. 646 */ 647 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid) 648 skb->csum_valid = 1; 649 } 650 651 #ifdef CONFIG_BPF_SYSCALL 652 struct sk_psock; 653 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 654 #endif 655 656 #endif /* _UDP_H */ 657