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54764bb647
commit 404e0a8b6a
(net: ipv4: fix RCU races on dst refcounts) tried
to solve a race but added a problem at device/fib dismantle time :
We really want to call dst_free() as soon as possible, even if sockets
still have dst in their cache.
dst_release() calls in free_fib_info_rcu() are not welcomed.
Root of the problem was that now we also cache output routes (in
nh_rth_output), we must use call_rcu() instead of call_rcu_bh() in
rt_free(), because output route lookups are done in process context.
Based on feedback and initial patch from David Miller (adding another
call_rcu_bh() call in fib, but it appears it was not the right fix)
I left the inet_sk_rx_dst_set() helper and added __rcu attributes
to nh_rth_output and nh_rth_input to better document what is going on in
this code.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
262 lines
6.4 KiB
C
262 lines
6.4 KiB
C
/*
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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 inet_sock
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*
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* Authors: Many, reorganised here by
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* Arnaldo Carvalho de Melo <acme@mandriva.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _INET_SOCK_H
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#define _INET_SOCK_H
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#include <linux/kmemcheck.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/jhash.h>
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#include <linux/netdevice.h>
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#include <net/flow.h>
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#include <net/sock.h>
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#include <net/request_sock.h>
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#include <net/netns/hash.h>
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/** struct ip_options - IP Options
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*
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* @faddr - Saved first hop address
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* @nexthop - Saved nexthop address in LSRR and SSRR
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* @is_data - Options in __data, rather than skb
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* @is_strictroute - Strict source route
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* @srr_is_hit - Packet destination addr was our one
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* @is_changed - IP checksum more not valid
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* @rr_needaddr - Need to record addr of outgoing dev
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* @ts_needtime - Need to record timestamp
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* @ts_needaddr - Need to record addr of outgoing dev
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*/
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struct ip_options {
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__be32 faddr;
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__be32 nexthop;
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unsigned char optlen;
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unsigned char srr;
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unsigned char rr;
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unsigned char ts;
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unsigned char is_strictroute:1,
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srr_is_hit:1,
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is_changed:1,
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rr_needaddr:1,
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ts_needtime:1,
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ts_needaddr:1;
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unsigned char router_alert;
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unsigned char cipso;
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unsigned char __pad2;
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unsigned char __data[0];
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};
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struct ip_options_rcu {
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struct rcu_head rcu;
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struct ip_options opt;
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};
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struct ip_options_data {
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struct ip_options_rcu opt;
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char data[40];
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};
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struct inet_request_sock {
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struct request_sock req;
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#if IS_ENABLED(CONFIG_IPV6)
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u16 inet6_rsk_offset;
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#endif
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__be16 loc_port;
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__be32 loc_addr;
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__be32 rmt_addr;
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__be16 rmt_port;
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kmemcheck_bitfield_begin(flags);
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u16 snd_wscale : 4,
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rcv_wscale : 4,
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tstamp_ok : 1,
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sack_ok : 1,
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wscale_ok : 1,
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ecn_ok : 1,
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acked : 1,
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no_srccheck: 1;
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kmemcheck_bitfield_end(flags);
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struct ip_options_rcu *opt;
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};
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static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
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{
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return (struct inet_request_sock *)sk;
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}
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struct inet_cork {
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unsigned int flags;
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__be32 addr;
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struct ip_options *opt;
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unsigned int fragsize;
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struct dst_entry *dst;
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int length; /* Total length of all frames */
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struct page *page;
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u32 off;
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u8 tx_flags;
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};
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struct inet_cork_full {
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struct inet_cork base;
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struct flowi fl;
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};
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struct ip_mc_socklist;
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struct ipv6_pinfo;
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struct rtable;
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/** struct inet_sock - representation of INET sockets
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*
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* @sk - ancestor class
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* @pinet6 - pointer to IPv6 control block
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* @inet_daddr - Foreign IPv4 addr
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* @inet_rcv_saddr - Bound local IPv4 addr
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* @inet_dport - Destination port
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* @inet_num - Local port
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* @inet_saddr - Sending source
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* @uc_ttl - Unicast TTL
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* @inet_sport - Source port
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* @inet_id - ID counter for DF pkts
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* @tos - TOS
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* @mc_ttl - Multicasting TTL
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* @is_icsk - is this an inet_connection_sock?
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* @uc_index - Unicast outgoing device index
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* @mc_index - Multicast device index
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* @mc_list - Group array
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* @cork - info to build ip hdr on each ip frag while socket is corked
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*/
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struct inet_sock {
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/* sk and pinet6 has to be the first two members of inet_sock */
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struct sock sk;
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#if IS_ENABLED(CONFIG_IPV6)
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struct ipv6_pinfo *pinet6;
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#endif
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/* Socket demultiplex comparisons on incoming packets. */
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#define inet_daddr sk.__sk_common.skc_daddr
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#define inet_rcv_saddr sk.__sk_common.skc_rcv_saddr
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__be16 inet_dport;
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__u16 inet_num;
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__be32 inet_saddr;
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__s16 uc_ttl;
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__u16 cmsg_flags;
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__be16 inet_sport;
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__u16 inet_id;
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struct ip_options_rcu __rcu *inet_opt;
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__u8 tos;
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__u8 min_ttl;
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__u8 mc_ttl;
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__u8 pmtudisc;
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__u8 recverr:1,
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is_icsk:1,
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freebind:1,
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hdrincl:1,
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mc_loop:1,
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transparent:1,
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mc_all:1,
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nodefrag:1;
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__u8 rcv_tos;
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int uc_index;
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int mc_index;
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__be32 mc_addr;
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int rx_dst_ifindex;
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struct ip_mc_socklist __rcu *mc_list;
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struct inet_cork_full cork;
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};
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#define IPCORK_OPT 1 /* ip-options has been held in ipcork.opt */
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#define IPCORK_ALLFRAG 2 /* always fragment (for ipv6 for now) */
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static inline struct inet_sock *inet_sk(const struct sock *sk)
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{
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return (struct inet_sock *)sk;
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}
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static inline void __inet_sk_copy_descendant(struct sock *sk_to,
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const struct sock *sk_from,
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const int ancestor_size)
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{
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memcpy(inet_sk(sk_to) + 1, inet_sk(sk_from) + 1,
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sk_from->sk_prot->obj_size - ancestor_size);
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}
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#if !(IS_ENABLED(CONFIG_IPV6))
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static inline void inet_sk_copy_descendant(struct sock *sk_to,
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const struct sock *sk_from)
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{
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__inet_sk_copy_descendant(sk_to, sk_from, sizeof(struct inet_sock));
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}
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#endif
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extern int inet_sk_rebuild_header(struct sock *sk);
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extern u32 inet_ehash_secret;
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extern void build_ehash_secret(void);
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static inline unsigned int inet_ehashfn(struct net *net,
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const __be32 laddr, const __u16 lport,
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const __be32 faddr, const __be16 fport)
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{
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return jhash_3words((__force __u32) laddr,
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(__force __u32) faddr,
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((__u32) lport) << 16 | (__force __u32)fport,
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inet_ehash_secret + net_hash_mix(net));
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}
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static inline int inet_sk_ehashfn(const struct sock *sk)
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{
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const struct inet_sock *inet = inet_sk(sk);
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const __be32 laddr = inet->inet_rcv_saddr;
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const __u16 lport = inet->inet_num;
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const __be32 faddr = inet->inet_daddr;
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const __be16 fport = inet->inet_dport;
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struct net *net = sock_net(sk);
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return inet_ehashfn(net, laddr, lport, faddr, fport);
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}
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static inline struct request_sock *inet_reqsk_alloc(struct request_sock_ops *ops)
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{
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struct request_sock *req = reqsk_alloc(ops);
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struct inet_request_sock *ireq = inet_rsk(req);
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if (req != NULL) {
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kmemcheck_annotate_bitfield(ireq, flags);
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ireq->opt = NULL;
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}
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return req;
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}
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static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
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{
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__u8 flags = 0;
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if (inet_sk(sk)->transparent || inet_sk(sk)->hdrincl)
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flags |= FLOWI_FLAG_ANYSRC;
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return flags;
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}
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static inline void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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dst_hold(dst);
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sk->sk_rx_dst = dst;
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inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
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}
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#endif /* _INET_SOCK_H */
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