527 строки
16 KiB
C
527 строки
16 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Definitions for the UDP module.
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*
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* Version: @(#)udp.h 1.0.2 05/07/93
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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*
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* Fixes:
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* Alan Cox : Turned on udp checksums. I don't want to
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* chase 'memory corruption' bugs that aren't!
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*/
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#ifndef _UDP_H
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#define _UDP_H
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#include <linux/list.h>
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#include <linux/bug.h>
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#include <net/inet_sock.h>
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#include <net/sock.h>
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#include <net/snmp.h>
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#include <net/ip.h>
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#include <linux/ipv6.h>
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#include <linux/seq_file.h>
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#include <linux/poll.h>
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#include <linux/indirect_call_wrapper.h>
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/**
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* struct udp_skb_cb - UDP(-Lite) private variables
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*
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* @header: private variables used by IPv4/IPv6
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* @cscov: checksum coverage length (UDP-Lite only)
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* @partial_cov: if set indicates partial csum coverage
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*/
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struct udp_skb_cb {
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union {
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struct inet_skb_parm h4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct inet6_skb_parm h6;
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#endif
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} header;
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__u16 cscov;
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__u8 partial_cov;
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};
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#define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
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/**
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* struct udp_hslot - UDP hash slot
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*
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* @head: head of list of sockets
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* @count: number of sockets in 'head' list
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* @lock: spinlock protecting changes to head/count
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*/
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struct udp_hslot {
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struct hlist_head head;
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int count;
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spinlock_t lock;
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} __attribute__((aligned(2 * sizeof(long))));
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/**
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* struct udp_table - UDP table
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*
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* @hash: hash table, sockets are hashed on (local port)
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* @hash2: hash table, sockets are hashed on (local port, local address)
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* @mask: number of slots in hash tables, minus 1
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* @log: log2(number of slots in hash table)
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*/
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struct udp_table {
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struct udp_hslot *hash;
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struct udp_hslot *hash2;
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unsigned int mask;
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unsigned int log;
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};
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extern struct udp_table udp_table;
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void udp_table_init(struct udp_table *, const char *);
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static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
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struct net *net, unsigned int num)
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{
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return &table->hash[udp_hashfn(net, num, table->mask)];
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}
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/*
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* For secondary hash, net_hash_mix() is performed before calling
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* udp_hashslot2(), this explains difference with udp_hashslot()
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*/
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static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
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unsigned int hash)
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{
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return &table->hash2[hash & table->mask];
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}
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extern struct proto udp_prot;
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extern atomic_long_t udp_memory_allocated;
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/* sysctl variables for udp */
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extern long sysctl_udp_mem[3];
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extern int sysctl_udp_rmem_min;
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extern int sysctl_udp_wmem_min;
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struct sk_buff;
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/*
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* Generic checksumming routines for UDP(-Lite) v4 and v6
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*/
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static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
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{
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return (UDP_SKB_CB(skb)->cscov == skb->len ?
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__skb_checksum_complete(skb) :
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__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
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}
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static inline int udp_lib_checksum_complete(struct sk_buff *skb)
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{
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return !skb_csum_unnecessary(skb) &&
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__udp_lib_checksum_complete(skb);
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}
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/**
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* udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
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* @sk: socket we are writing to
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* @skb: sk_buff containing the filled-in UDP header
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* (checksum field must be zeroed out)
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*/
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static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
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{
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__wsum csum = csum_partial(skb_transport_header(skb),
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sizeof(struct udphdr), 0);
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skb_queue_walk(&sk->sk_write_queue, skb) {
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csum = csum_add(csum, skb->csum);
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}
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return csum;
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}
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static inline __wsum udp_csum(struct sk_buff *skb)
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{
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__wsum csum = csum_partial(skb_transport_header(skb),
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sizeof(struct udphdr), skb->csum);
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for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
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csum = csum_add(csum, skb->csum);
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}
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return csum;
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}
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static inline __sum16 udp_v4_check(int len, __be32 saddr,
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__be32 daddr, __wsum base)
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{
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return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
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}
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void udp_set_csum(bool nocheck, struct sk_buff *skb,
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__be32 saddr, __be32 daddr, int len);
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static inline void udp_csum_pull_header(struct sk_buff *skb)
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{
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if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
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skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
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skb->csum);
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skb_pull_rcsum(skb, sizeof(struct udphdr));
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UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
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}
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typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
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__be16 dport);
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INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *));
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INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
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struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
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netdev_features_t features, bool is_ipv6);
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/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
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static inline int udp_lib_hash(struct sock *sk)
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{
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BUG();
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return 0;
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}
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void udp_lib_unhash(struct sock *sk);
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void udp_lib_rehash(struct sock *sk, u16 new_hash);
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static inline void udp_lib_close(struct sock *sk, long timeout)
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{
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sk_common_release(sk);
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}
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int udp_lib_get_port(struct sock *sk, unsigned short snum,
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unsigned int hash2_nulladdr);
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u32 udp_flow_hashrnd(void);
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static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
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int min, int max, bool use_eth)
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{
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u32 hash;
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if (min >= max) {
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/* Use default range */
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inet_get_local_port_range(net, &min, &max);
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}
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hash = skb_get_hash(skb);
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if (unlikely(!hash)) {
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if (use_eth) {
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/* Can't find a normal hash, caller has indicated an
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* Ethernet packet so use that to compute a hash.
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*/
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hash = jhash(skb->data, 2 * ETH_ALEN,
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(__force u32) skb->protocol);
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} else {
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/* Can't derive any sort of hash for the packet, set
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* to some consistent random value.
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*/
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hash = udp_flow_hashrnd();
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}
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}
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/* Since this is being sent on the wire obfuscate hash a bit
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* to minimize possbility that any useful information to an
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* attacker is leaked. Only upper 16 bits are relevant in the
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* computation for 16 bit port value.
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*/
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hash ^= hash << 16;
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return htons((((u64) hash * (max - min)) >> 32) + min);
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}
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static inline int udp_rqueue_get(struct sock *sk)
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{
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return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
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}
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static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
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int dif, int sdif)
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{
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#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
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return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept,
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bound_dev_if, dif, sdif);
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#else
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return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
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#endif
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}
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/* net/ipv4/udp.c */
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void udp_destruct_sock(struct sock *sk);
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void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
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int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
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void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
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struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
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int noblock, int *off, int *err);
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static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
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int noblock, int *err)
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{
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int off = 0;
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return __skb_recv_udp(sk, flags, noblock, &off, err);
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}
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int udp_v4_early_demux(struct sk_buff *skb);
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bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
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int udp_get_port(struct sock *sk, unsigned short snum,
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int (*saddr_cmp)(const struct sock *,
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const struct sock *));
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int udp_err(struct sk_buff *, u32);
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int udp_abort(struct sock *sk, int err);
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int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
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int udp_push_pending_frames(struct sock *sk);
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void udp_flush_pending_frames(struct sock *sk);
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int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
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void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
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int udp_rcv(struct sk_buff *skb);
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int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
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int udp_init_sock(struct sock *sk);
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int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
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int __udp_disconnect(struct sock *sk, int flags);
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int udp_disconnect(struct sock *sk, int flags);
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__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
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struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
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netdev_features_t features,
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bool is_ipv6);
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int udp_lib_getsockopt(struct sock *sk, int level, int optname,
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char __user *optval, int __user *optlen);
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int udp_lib_setsockopt(struct sock *sk, int level, int optname,
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sockptr_t optval, unsigned int optlen,
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int (*push_pending_frames)(struct sock *));
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struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
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__be32 daddr, __be16 dport, int dif);
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struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
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__be32 daddr, __be16 dport, int dif, int sdif,
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struct udp_table *tbl, struct sk_buff *skb);
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struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
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__be16 sport, __be16 dport);
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struct sock *udp6_lib_lookup(struct net *net,
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const struct in6_addr *saddr, __be16 sport,
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const struct in6_addr *daddr, __be16 dport,
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int dif);
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struct sock *__udp6_lib_lookup(struct net *net,
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const struct in6_addr *saddr, __be16 sport,
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const struct in6_addr *daddr, __be16 dport,
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int dif, int sdif, struct udp_table *tbl,
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struct sk_buff *skb);
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struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
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__be16 sport, __be16 dport);
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int udp_read_sock(struct sock *sk, read_descriptor_t *desc,
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sk_read_actor_t recv_actor);
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/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
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* possibly multiple cache miss on dequeue()
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*/
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struct udp_dev_scratch {
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/* skb->truesize and the stateless bit are embedded in a single field;
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* do not use a bitfield since the compiler emits better/smaller code
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* this way
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*/
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u32 _tsize_state;
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#if BITS_PER_LONG == 64
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/* len and the bit needed to compute skb_csum_unnecessary
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* will be on cold cache lines at recvmsg time.
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* skb->len can be stored on 16 bits since the udp header has been
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* already validated and pulled.
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*/
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u16 len;
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bool is_linear;
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bool csum_unnecessary;
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#endif
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};
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static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
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{
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return (struct udp_dev_scratch *)&skb->dev_scratch;
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}
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#if BITS_PER_LONG == 64
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static inline unsigned int udp_skb_len(struct sk_buff *skb)
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{
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return udp_skb_scratch(skb)->len;
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}
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static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
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{
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return udp_skb_scratch(skb)->csum_unnecessary;
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}
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static inline bool udp_skb_is_linear(struct sk_buff *skb)
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{
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return udp_skb_scratch(skb)->is_linear;
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}
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#else
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static inline unsigned int udp_skb_len(struct sk_buff *skb)
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{
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return skb->len;
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}
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static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
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{
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return skb_csum_unnecessary(skb);
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}
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static inline bool udp_skb_is_linear(struct sk_buff *skb)
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{
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return !skb_is_nonlinear(skb);
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}
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#endif
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static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
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struct iov_iter *to)
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{
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int n;
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n = copy_to_iter(skb->data + off, len, to);
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if (n == len)
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return 0;
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iov_iter_revert(to, n);
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return -EFAULT;
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}
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/*
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* SNMP statistics for UDP and UDP-Lite
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*/
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#define UDP_INC_STATS(net, field, is_udplite) do { \
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if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
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else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
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#define __UDP_INC_STATS(net, field, is_udplite) do { \
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if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
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else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
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#define __UDP6_INC_STATS(net, field, is_udplite) do { \
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if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
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else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
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} while(0)
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#define UDP6_INC_STATS(net, field, __lite) do { \
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if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
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else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
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} while(0)
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#if IS_ENABLED(CONFIG_IPV6)
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#define __UDPX_MIB(sk, ipv4) \
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({ \
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ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
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sock_net(sk)->mib.udp_statistics) : \
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(IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
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sock_net(sk)->mib.udp_stats_in6); \
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})
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#else
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#define __UDPX_MIB(sk, ipv4) \
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({ \
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IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
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sock_net(sk)->mib.udp_statistics; \
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})
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#endif
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#define __UDPX_INC_STATS(sk, field) \
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__SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
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#ifdef CONFIG_PROC_FS
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struct udp_seq_afinfo {
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sa_family_t family;
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struct udp_table *udp_table;
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};
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struct udp_iter_state {
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struct seq_net_private p;
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int bucket;
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struct udp_seq_afinfo *bpf_seq_afinfo;
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};
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void *udp_seq_start(struct seq_file *seq, loff_t *pos);
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void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
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void udp_seq_stop(struct seq_file *seq, void *v);
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extern const struct seq_operations udp_seq_ops;
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extern const struct seq_operations udp6_seq_ops;
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int udp4_proc_init(void);
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void udp4_proc_exit(void);
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#endif /* CONFIG_PROC_FS */
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int udpv4_offload_init(void);
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void udp_init(void);
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DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
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void udp_encap_enable(void);
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void udp_encap_disable(void);
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#if IS_ENABLED(CONFIG_IPV6)
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DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
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void udpv6_encap_enable(void);
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#endif
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static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
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struct sk_buff *skb, bool ipv4)
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{
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netdev_features_t features = NETIF_F_SG;
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struct sk_buff *segs;
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|
|
|
/* Avoid csum recalculation by skb_segment unless userspace explicitly
|
|
* asks for the final checksum values
|
|
*/
|
|
if (!inet_get_convert_csum(sk))
|
|
features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
|
|
|
|
/* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
|
|
* CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
|
|
* packets in udp_gro_complete_segment. As does UDP GSO, verified by
|
|
* udp_send_skb. But when those packets are looped in dev_loopback_xmit
|
|
* their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
|
|
* Reset in this specific case, where PARTIAL is both correct and
|
|
* required.
|
|
*/
|
|
if (skb->pkt_type == PACKET_LOOPBACK)
|
|
skb->ip_summed = CHECKSUM_PARTIAL;
|
|
|
|
/* the GSO CB lays after the UDP one, no need to save and restore any
|
|
* CB fragment
|
|
*/
|
|
segs = __skb_gso_segment(skb, features, false);
|
|
if (IS_ERR_OR_NULL(segs)) {
|
|
int segs_nr = skb_shinfo(skb)->gso_segs;
|
|
|
|
atomic_add(segs_nr, &sk->sk_drops);
|
|
SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
|
|
kfree_skb(skb);
|
|
return NULL;
|
|
}
|
|
|
|
consume_skb(skb);
|
|
return segs;
|
|
}
|
|
|
|
static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
|
|
{
|
|
/* UDP-lite can't land here - no GRO */
|
|
WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
|
|
|
|
/* UDP packets generated with UDP_SEGMENT and traversing:
|
|
*
|
|
* UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
|
|
*
|
|
* can reach an UDP socket with CHECKSUM_NONE, because
|
|
* __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
|
|
* SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
|
|
* have a valid checksum, as the GRO engine validates the UDP csum
|
|
* before the aggregation and nobody strips such info in between.
|
|
* Instead of adding another check in the tunnel fastpath, we can force
|
|
* a valid csum after the segmentation.
|
|
* Additionally fixup the UDP CB.
|
|
*/
|
|
UDP_SKB_CB(skb)->cscov = skb->len;
|
|
if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
|
|
skb->csum_valid = 1;
|
|
}
|
|
|
|
#ifdef CONFIG_BPF_SYSCALL
|
|
struct sk_psock;
|
|
struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
|
|
int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
|
|
#endif
|
|
|
|
#endif /* _UDP_H */
|