![Matteo Croce](/assets/img/avatar_default.png)
In the sysctl code the proc_dointvec_minmax() function is often used to validate the user supplied value between an allowed range. This function uses the extra1 and extra2 members from struct ctl_table as minimum and maximum allowed value. On sysctl handler declaration, in every source file there are some readonly variables containing just an integer which address is assigned to the extra1 and extra2 members, so the sysctl range is enforced. The special values 0, 1 and INT_MAX are very often used as range boundary, leading duplication of variables like zero=0, one=1, int_max=INT_MAX in different source files: $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l 248 Add a const int array containing the most commonly used values, some macros to refer more easily to the correct array member, and use them instead of creating a local one for every object file. This is the bloat-o-meter output comparing the old and new binary compiled with the default Fedora config: # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164) Data old new delta sysctl_vals - 12 +12 __kstrtab_sysctl_vals - 12 +12 max 14 10 -4 int_max 16 - -16 one 68 - -68 zero 128 28 -100 Total: Before=20583249, After=20583085, chg -0.00% [mcroce@redhat.com: tipc: remove two unused variables] Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com [akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c] [arnd@arndb.de: proc/sysctl: make firmware loader table conditional] Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de [akpm@linux-foundation.org: fix fs/eventpoll.c] Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
505 lines
12 KiB
C
505 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* SCTP kernel implementation
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* (C) Copyright IBM Corp. 2002, 2004
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* Copyright (c) 2002 Intel Corp.
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*
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* This file is part of the SCTP kernel implementation
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*
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* Sysctl related interfaces for SCTP.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <linux-sctp@vger.kernel.org>
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*
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* Written or modified by:
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* Mingqin Liu <liuming@us.ibm.com>
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* Jon Grimm <jgrimm@us.ibm.com>
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* Ardelle Fan <ardelle.fan@intel.com>
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* Ryan Layer <rmlayer@us.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <net/sctp/structs.h>
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#include <net/sctp/sctp.h>
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#include <linux/sysctl.h>
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static int timer_max = 86400000; /* ms in one day */
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static int sack_timer_min = 1;
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static int sack_timer_max = 500;
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static int addr_scope_max = SCTP_SCOPE_POLICY_MAX;
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static int rwnd_scale_max = 16;
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static int rto_alpha_min = 0;
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static int rto_beta_min = 0;
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static int rto_alpha_max = 1000;
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static int rto_beta_max = 1000;
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static unsigned long max_autoclose_min = 0;
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static unsigned long max_autoclose_max =
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(MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
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? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ;
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static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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static struct ctl_table sctp_table[] = {
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{
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.procname = "sctp_mem",
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.data = &sysctl_sctp_mem,
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.maxlen = sizeof(sysctl_sctp_mem),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax
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},
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{
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.procname = "sctp_rmem",
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.data = &sysctl_sctp_rmem,
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.maxlen = sizeof(sysctl_sctp_rmem),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "sctp_wmem",
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.data = &sysctl_sctp_wmem,
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.maxlen = sizeof(sysctl_sctp_wmem),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{ /* sentinel */ }
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};
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static struct ctl_table sctp_net_table[] = {
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{
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.procname = "rto_initial",
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.data = &init_net.sctp.rto_initial,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = &timer_max
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},
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{
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.procname = "rto_min",
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.data = &init_net.sctp.rto_min,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_sctp_do_rto_min,
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.extra1 = SYSCTL_ONE,
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.extra2 = &init_net.sctp.rto_max
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},
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{
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.procname = "rto_max",
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.data = &init_net.sctp.rto_max,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_sctp_do_rto_max,
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.extra1 = &init_net.sctp.rto_min,
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.extra2 = &timer_max
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},
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{
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.procname = "rto_alpha_exp_divisor",
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.data = &init_net.sctp.rto_alpha,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_sctp_do_alpha_beta,
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.extra1 = &rto_alpha_min,
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.extra2 = &rto_alpha_max,
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},
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{
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.procname = "rto_beta_exp_divisor",
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.data = &init_net.sctp.rto_beta,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_sctp_do_alpha_beta,
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.extra1 = &rto_beta_min,
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.extra2 = &rto_beta_max,
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},
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{
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.procname = "max_burst",
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.data = &init_net.sctp.max_burst,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "cookie_preserve_enable",
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.data = &init_net.sctp.cookie_preserve_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "cookie_hmac_alg",
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.data = &init_net.sctp.sctp_hmac_alg,
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.maxlen = 8,
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.mode = 0644,
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.proc_handler = proc_sctp_do_hmac_alg,
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},
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{
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.procname = "valid_cookie_life",
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.data = &init_net.sctp.valid_cookie_life,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = &timer_max
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},
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{
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.procname = "sack_timeout",
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.data = &init_net.sctp.sack_timeout,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &sack_timer_min,
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.extra2 = &sack_timer_max,
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},
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{
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.procname = "hb_interval",
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.data = &init_net.sctp.hb_interval,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = &timer_max
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},
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{
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.procname = "association_max_retrans",
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.data = &init_net.sctp.max_retrans_association,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "path_max_retrans",
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.data = &init_net.sctp.max_retrans_path,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "max_init_retransmits",
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.data = &init_net.sctp.max_retrans_init,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "pf_retrans",
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.data = &init_net.sctp.pf_retrans,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "sndbuf_policy",
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.data = &init_net.sctp.sndbuf_policy,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "rcvbuf_policy",
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.data = &init_net.sctp.rcvbuf_policy,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "default_auto_asconf",
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.data = &init_net.sctp.default_auto_asconf,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "addip_enable",
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.data = &init_net.sctp.addip_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "addip_noauth_enable",
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.data = &init_net.sctp.addip_noauth,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "prsctp_enable",
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.data = &init_net.sctp.prsctp_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "reconf_enable",
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.data = &init_net.sctp.reconf_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "auth_enable",
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.data = &init_net.sctp.auth_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_sctp_do_auth,
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},
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{
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.procname = "intl_enable",
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.data = &init_net.sctp.intl_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "addr_scope_policy",
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.data = &init_net.sctp.scope_policy,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &addr_scope_max,
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},
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{
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.procname = "rwnd_update_shift",
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.data = &init_net.sctp.rwnd_upd_shift,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = &rwnd_scale_max,
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},
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{
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.procname = "max_autoclose",
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.data = &init_net.sctp.max_autoclose,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = &proc_doulongvec_minmax,
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.extra1 = &max_autoclose_min,
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.extra2 = &max_autoclose_max,
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},
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{
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.procname = "pf_enable",
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.data = &init_net.sctp.pf_enable,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{ /* sentinel */ }
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};
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static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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struct net *net = current->nsproxy->net_ns;
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struct ctl_table tbl;
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bool changed = false;
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char *none = "none";
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char tmp[8] = {0};
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int ret;
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memset(&tbl, 0, sizeof(struct ctl_table));
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if (write) {
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tbl.data = tmp;
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tbl.maxlen = sizeof(tmp);
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} else {
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tbl.data = net->sctp.sctp_hmac_alg ? : none;
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tbl.maxlen = strlen(tbl.data);
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}
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ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
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if (write && ret == 0) {
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#ifdef CONFIG_CRYPTO_MD5
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if (!strncmp(tmp, "md5", 3)) {
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net->sctp.sctp_hmac_alg = "md5";
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changed = true;
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}
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#endif
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#ifdef CONFIG_CRYPTO_SHA1
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if (!strncmp(tmp, "sha1", 4)) {
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net->sctp.sctp_hmac_alg = "sha1";
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changed = true;
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}
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#endif
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if (!strncmp(tmp, "none", 4)) {
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net->sctp.sctp_hmac_alg = NULL;
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changed = true;
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}
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if (!changed)
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ret = -EINVAL;
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}
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return ret;
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}
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static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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struct net *net = current->nsproxy->net_ns;
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unsigned int min = *(unsigned int *) ctl->extra1;
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unsigned int max = *(unsigned int *) ctl->extra2;
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struct ctl_table tbl;
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int ret, new_value;
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memset(&tbl, 0, sizeof(struct ctl_table));
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tbl.maxlen = sizeof(unsigned int);
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if (write)
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tbl.data = &new_value;
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else
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tbl.data = &net->sctp.rto_min;
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ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
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if (write && ret == 0) {
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if (new_value > max || new_value < min)
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return -EINVAL;
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net->sctp.rto_min = new_value;
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}
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return ret;
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}
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static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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struct net *net = current->nsproxy->net_ns;
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unsigned int min = *(unsigned int *) ctl->extra1;
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unsigned int max = *(unsigned int *) ctl->extra2;
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struct ctl_table tbl;
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int ret, new_value;
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memset(&tbl, 0, sizeof(struct ctl_table));
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tbl.maxlen = sizeof(unsigned int);
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if (write)
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tbl.data = &new_value;
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else
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tbl.data = &net->sctp.rto_max;
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ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
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if (write && ret == 0) {
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if (new_value > max || new_value < min)
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return -EINVAL;
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net->sctp.rto_max = new_value;
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}
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return ret;
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}
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static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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if (write)
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pr_warn_once("Changing rto_alpha or rto_beta may lead to "
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"suboptimal rtt/srtt estimations!\n");
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return proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
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}
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static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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struct net *net = current->nsproxy->net_ns;
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struct ctl_table tbl;
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int new_value, ret;
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memset(&tbl, 0, sizeof(struct ctl_table));
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tbl.maxlen = sizeof(unsigned int);
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if (write)
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tbl.data = &new_value;
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else
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tbl.data = &net->sctp.auth_enable;
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ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
|
|
if (write && ret == 0) {
|
|
struct sock *sk = net->sctp.ctl_sock;
|
|
|
|
net->sctp.auth_enable = new_value;
|
|
/* Update the value in the control socket */
|
|
lock_sock(sk);
|
|
sctp_sk(sk)->ep->auth_enable = new_value;
|
|
release_sock(sk);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int sctp_sysctl_net_register(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
int i;
|
|
|
|
table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
|
|
if (!table)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; table[i].data; i++)
|
|
table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
|
|
|
|
net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);
|
|
if (net->sctp.sysctl_header == NULL) {
|
|
kfree(table);
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void sctp_sysctl_net_unregister(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
|
|
table = net->sctp.sysctl_header->ctl_table_arg;
|
|
unregister_net_sysctl_table(net->sctp.sysctl_header);
|
|
kfree(table);
|
|
}
|
|
|
|
static struct ctl_table_header *sctp_sysctl_header;
|
|
|
|
/* Sysctl registration. */
|
|
void sctp_sysctl_register(void)
|
|
{
|
|
sctp_sysctl_header = register_net_sysctl(&init_net, "net/sctp", sctp_table);
|
|
}
|
|
|
|
/* Sysctl deregistration. */
|
|
void sctp_sysctl_unregister(void)
|
|
{
|
|
unregister_net_sysctl_table(sctp_sysctl_header);
|
|
}
|