1 /* SPDX-License-Identifier: GPL-2.0-or-later */
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.
7 * Definitions for the UDP module.
9 * Version: @(#)udp.h 1.0.2 05/07/93
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
15 * Alan Cox : Turned on udp checksums. I don't want to
16 * chase 'memory corruption' bugs that aren't!
21 #include <linux/list.h>
22 #include <linux/bug.h>
23 #include <net/inet_sock.h>
27 #include <linux/ipv6.h>
28 #include <linux/seq_file.h>
29 #include <linux/poll.h>
30 #include <linux/indirect_call_wrapper.h>
33 * struct udp_skb_cb - UDP(-Lite) private variables
35 * @header: private variables used by IPv4/IPv6
36 * @cscov: checksum coverage length (UDP-Lite only)
37 * @partial_cov: if set indicates partial csum coverage
41 struct inet_skb_parm h4;
42 #if IS_ENABLED(CONFIG_IPV6)
43 struct inet6_skb_parm h6;
49 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
52 * struct udp_hslot - UDP hash slot
54 * @head: head of list of sockets
55 * @count: number of sockets in 'head' list
56 * @lock: spinlock protecting changes to head/count
59 struct hlist_head head;
62 } __attribute__((aligned(2 * sizeof(long))));
65 * struct udp_table - UDP table
67 * @hash: hash table, sockets are hashed on (local port)
68 * @hash2: hash table, sockets are hashed on (local port, local address)
69 * @mask: number of slots in hash tables, minus 1
70 * @log: log2(number of slots in hash table)
73 struct udp_hslot *hash;
74 struct udp_hslot *hash2;
78 extern struct udp_table udp_table;
79 void udp_table_init(struct udp_table *, const char *);
80 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
81 struct net *net, unsigned int num)
83 return &table->hash[udp_hashfn(net, num, table->mask)];
86 * For secondary hash, net_hash_mix() is performed before calling
87 * udp_hashslot2(), this explains difference with udp_hashslot()
89 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
92 return &table->hash2[hash & table->mask];
95 extern struct proto udp_prot;
97 extern atomic_long_t udp_memory_allocated;
99 /* sysctl variables for udp */
100 extern long sysctl_udp_mem[3];
101 extern int sysctl_udp_rmem_min;
102 extern int sysctl_udp_wmem_min;
107 * Generic checksumming routines for UDP(-Lite) v4 and v6
109 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
111 return (UDP_SKB_CB(skb)->cscov == skb->len ?
112 __skb_checksum_complete(skb) :
113 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
116 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
118 return !skb_csum_unnecessary(skb) &&
119 __udp_lib_checksum_complete(skb);
123 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
124 * @sk: socket we are writing to
125 * @skb: sk_buff containing the filled-in UDP header
126 * (checksum field must be zeroed out)
128 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
130 __wsum csum = csum_partial(skb_transport_header(skb),
131 sizeof(struct udphdr), 0);
132 skb_queue_walk(&sk->sk_write_queue, skb) {
133 csum = csum_add(csum, skb->csum);
138 static inline __wsum udp_csum(struct sk_buff *skb)
140 __wsum csum = csum_partial(skb_transport_header(skb),
141 sizeof(struct udphdr), skb->csum);
143 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
144 csum = csum_add(csum, skb->csum);
149 static inline __sum16 udp_v4_check(int len, __be32 saddr,
150 __be32 daddr, __wsum base)
152 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
155 void udp_set_csum(bool nocheck, struct sk_buff *skb,
156 __be32 saddr, __be32 daddr, int len);
158 static inline void udp_csum_pull_header(struct sk_buff *skb)
160 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
161 skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
163 skb_pull_rcsum(skb, sizeof(struct udphdr));
164 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
167 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
170 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *,
172 INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int));
173 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
175 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
176 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
177 struct udphdr *uh, struct sock *sk);
178 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
179 void udp_v6_early_demux(struct sk_buff *skb);
181 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
182 netdev_features_t features, bool is_ipv6);
184 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
187 unsigned int hlen, off;
189 off = skb_gro_offset(skb);
190 hlen = off + sizeof(*uh);
191 uh = skb_gro_header_fast(skb, off);
192 if (skb_gro_header_hard(skb, hlen))
193 uh = skb_gro_header_slow(skb, hlen, off);
198 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
199 static inline int udp_lib_hash(struct sock *sk)
205 void udp_lib_unhash(struct sock *sk);
206 void udp_lib_rehash(struct sock *sk, u16 new_hash);
208 static inline void udp_lib_close(struct sock *sk, long timeout)
210 sk_common_release(sk);
213 int udp_lib_get_port(struct sock *sk, unsigned short snum,
214 unsigned int hash2_nulladdr);
216 u32 udp_flow_hashrnd(void);
218 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
219 int min, int max, bool use_eth)
224 /* Use default range */
225 inet_get_local_port_range(net, &min, &max);
228 hash = skb_get_hash(skb);
229 if (unlikely(!hash)) {
231 /* Can't find a normal hash, caller has indicated an
232 * Ethernet packet so use that to compute a hash.
234 hash = jhash(skb->data, 2 * ETH_ALEN,
235 (__force u32) skb->protocol);
237 /* Can't derive any sort of hash for the packet, set
238 * to some consistent random value.
240 hash = udp_flow_hashrnd();
244 /* Since this is being sent on the wire obfuscate hash a bit
245 * to minimize possbility that any useful information to an
246 * attacker is leaked. Only upper 16 bits are relevant in the
247 * computation for 16 bit port value.
251 return htons((((u64) hash * (max - min)) >> 32) + min);
254 static inline int udp_rqueue_get(struct sock *sk)
256 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
259 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
262 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
263 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
264 bound_dev_if, dif, sdif);
266 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
271 void udp_destruct_common(struct sock *sk);
272 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
273 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
274 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
275 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
276 int noblock, int *off, int *err);
277 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
278 int noblock, int *err)
282 return __skb_recv_udp(sk, flags, noblock, &off, err);
285 int udp_v4_early_demux(struct sk_buff *skb);
286 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
287 int udp_get_port(struct sock *sk, unsigned short snum,
288 int (*saddr_cmp)(const struct sock *,
289 const struct sock *));
290 int udp_err(struct sk_buff *, u32);
291 int udp_abort(struct sock *sk, int err);
292 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
293 int udp_push_pending_frames(struct sock *sk);
294 void udp_flush_pending_frames(struct sock *sk);
295 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
296 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
297 int udp_rcv(struct sk_buff *skb);
298 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
299 int udp_init_sock(struct sock *sk);
300 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
301 int __udp_disconnect(struct sock *sk, int flags);
302 int udp_disconnect(struct sock *sk, int flags);
303 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
304 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
305 netdev_features_t features,
307 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
308 char __user *optval, int __user *optlen);
309 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
310 sockptr_t optval, unsigned int optlen,
311 int (*push_pending_frames)(struct sock *));
312 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
313 __be32 daddr, __be16 dport, int dif);
314 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
315 __be32 daddr, __be16 dport, int dif, int sdif,
316 struct udp_table *tbl, struct sk_buff *skb);
317 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
318 __be16 sport, __be16 dport);
319 struct sock *udp6_lib_lookup(struct net *net,
320 const struct in6_addr *saddr, __be16 sport,
321 const struct in6_addr *daddr, __be16 dport,
323 struct sock *__udp6_lib_lookup(struct net *net,
324 const struct in6_addr *saddr, __be16 sport,
325 const struct in6_addr *daddr, __be16 dport,
326 int dif, int sdif, struct udp_table *tbl,
327 struct sk_buff *skb);
328 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
329 __be16 sport, __be16 dport);
331 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
332 * possibly multiple cache miss on dequeue()
334 struct udp_dev_scratch {
335 /* skb->truesize and the stateless bit are embedded in a single field;
336 * do not use a bitfield since the compiler emits better/smaller code
341 #if BITS_PER_LONG == 64
342 /* len and the bit needed to compute skb_csum_unnecessary
343 * will be on cold cache lines at recvmsg time.
344 * skb->len can be stored on 16 bits since the udp header has been
345 * already validated and pulled.
349 bool csum_unnecessary;
353 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
355 return (struct udp_dev_scratch *)&skb->dev_scratch;
358 #if BITS_PER_LONG == 64
359 static inline unsigned int udp_skb_len(struct sk_buff *skb)
361 return udp_skb_scratch(skb)->len;
364 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
366 return udp_skb_scratch(skb)->csum_unnecessary;
369 static inline bool udp_skb_is_linear(struct sk_buff *skb)
371 return udp_skb_scratch(skb)->is_linear;
375 static inline unsigned int udp_skb_len(struct sk_buff *skb)
380 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
382 return skb_csum_unnecessary(skb);
385 static inline bool udp_skb_is_linear(struct sk_buff *skb)
387 return !skb_is_nonlinear(skb);
391 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
396 n = copy_to_iter(skb->data + off, len, to);
400 iov_iter_revert(to, n);
405 * SNMP statistics for UDP and UDP-Lite
407 #define UDP_INC_STATS(net, field, is_udplite) do { \
408 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
409 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
410 #define __UDP_INC_STATS(net, field, is_udplite) do { \
411 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
412 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
414 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
415 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
416 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
418 #define UDP6_INC_STATS(net, field, __lite) do { \
419 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
420 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
423 #if IS_ENABLED(CONFIG_IPV6)
424 #define __UDPX_MIB(sk, ipv4) \
426 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
427 sock_net(sk)->mib.udp_statistics) : \
428 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
429 sock_net(sk)->mib.udp_stats_in6); \
432 #define __UDPX_MIB(sk, ipv4) \
434 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
435 sock_net(sk)->mib.udp_statistics; \
439 #define __UDPX_INC_STATS(sk, field) \
440 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
442 #ifdef CONFIG_PROC_FS
443 struct udp_seq_afinfo {
445 struct udp_table *udp_table;
448 struct udp_iter_state {
449 struct seq_net_private p;
451 struct udp_seq_afinfo *bpf_seq_afinfo;
454 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
455 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
456 void udp_seq_stop(struct seq_file *seq, void *v);
458 extern const struct seq_operations udp_seq_ops;
459 extern const struct seq_operations udp6_seq_ops;
461 int udp4_proc_init(void);
462 void udp4_proc_exit(void);
463 #endif /* CONFIG_PROC_FS */
465 int udpv4_offload_init(void);
469 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
470 void udp_encap_enable(void);
471 void udp_encap_disable(void);
472 #if IS_ENABLED(CONFIG_IPV6)
473 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
474 void udpv6_encap_enable(void);
477 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
478 struct sk_buff *skb, bool ipv4)
480 netdev_features_t features = NETIF_F_SG;
481 struct sk_buff *segs;
483 /* Avoid csum recalculation by skb_segment unless userspace explicitly
484 * asks for the final checksum values
486 if (!inet_get_convert_csum(sk))
487 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
489 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
490 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
491 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
492 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
493 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
494 * Reset in this specific case, where PARTIAL is both correct and
497 if (skb->pkt_type == PACKET_LOOPBACK)
498 skb->ip_summed = CHECKSUM_PARTIAL;
500 /* the GSO CB lays after the UDP one, no need to save and restore any
503 segs = __skb_gso_segment(skb, features, false);
504 if (IS_ERR_OR_NULL(segs)) {
505 int segs_nr = skb_shinfo(skb)->gso_segs;
507 atomic_add(segs_nr, &sk->sk_drops);
508 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
517 #ifdef CONFIG_BPF_STREAM_PARSER
519 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
520 #endif /* BPF_STREAM_PARSER */