![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>
318 lines
8 KiB
C
318 lines
8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* sysctl_net_ipv6.c: sysctl interface to net IPV6 subsystem.
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*
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* Changes:
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* YOSHIFUJI Hideaki @USAGI: added icmp sysctl table.
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*/
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#include <linux/mm.h>
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#include <linux/sysctl.h>
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#include <linux/in6.h>
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#include <linux/ipv6.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <net/ndisc.h>
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#include <net/ipv6.h>
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#include <net/addrconf.h>
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#include <net/inet_frag.h>
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#include <net/netevent.h>
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#ifdef CONFIG_NETLABEL
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#include <net/calipso.h>
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#endif
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static int flowlabel_reflect_max = 0x7;
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static int auto_flowlabels_min;
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static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
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static int proc_rt6_multipath_hash_policy(struct ctl_table *table, 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;
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int ret;
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net = container_of(table->data, struct net,
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ipv6.sysctl.multipath_hash_policy);
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ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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if (write && ret == 0)
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call_netevent_notifiers(NETEVENT_IPV6_MPATH_HASH_UPDATE, net);
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return ret;
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}
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static struct ctl_table ipv6_table_template[] = {
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{
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.procname = "bindv6only",
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.data = &init_net.ipv6.sysctl.bindv6only,
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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 = "anycast_src_echo_reply",
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.data = &init_net.ipv6.sysctl.anycast_src_echo_reply,
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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 = "flowlabel_consistency",
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.data = &init_net.ipv6.sysctl.flowlabel_consistency,
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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 = "auto_flowlabels",
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.data = &init_net.ipv6.sysctl.auto_flowlabels,
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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 = &auto_flowlabels_min,
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.extra2 = &auto_flowlabels_max
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},
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{
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.procname = "fwmark_reflect",
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.data = &init_net.ipv6.sysctl.fwmark_reflect,
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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 = "idgen_retries",
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.data = &init_net.ipv6.sysctl.idgen_retries,
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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 = "idgen_delay",
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.data = &init_net.ipv6.sysctl.idgen_delay,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_jiffies,
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},
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{
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.procname = "flowlabel_state_ranges",
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.data = &init_net.ipv6.sysctl.flowlabel_state_ranges,
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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 = "ip_nonlocal_bind",
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.data = &init_net.ipv6.sysctl.ip_nonlocal_bind,
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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 = "flowlabel_reflect",
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.data = &init_net.ipv6.sysctl.flowlabel_reflect,
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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 = &flowlabel_reflect_max,
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},
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{
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.procname = "max_dst_opts_number",
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.data = &init_net.ipv6.sysctl.max_dst_opts_cnt,
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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 = "max_hbh_opts_number",
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.data = &init_net.ipv6.sysctl.max_hbh_opts_cnt,
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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 = "max_dst_opts_length",
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.data = &init_net.ipv6.sysctl.max_dst_opts_len,
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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 = "max_hbh_length",
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.data = &init_net.ipv6.sysctl.max_hbh_opts_len,
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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 = "fib_multipath_hash_policy",
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.data = &init_net.ipv6.sysctl.multipath_hash_policy,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_rt6_multipath_hash_policy,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_ONE,
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},
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{
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.procname = "seg6_flowlabel",
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.data = &init_net.ipv6.sysctl.seg6_flowlabel,
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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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};
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static struct ctl_table ipv6_rotable[] = {
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{
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.procname = "mld_max_msf",
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.data = &sysctl_mld_max_msf,
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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 = "mld_qrv",
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.data = &sysctl_mld_qrv,
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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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},
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#ifdef CONFIG_NETLABEL
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{
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.procname = "calipso_cache_enable",
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.data = &calipso_cache_enabled,
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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 = "calipso_cache_bucket_size",
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.data = &calipso_cache_bucketsize,
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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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#endif /* CONFIG_NETLABEL */
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{ }
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};
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static int __net_init ipv6_sysctl_net_init(struct net *net)
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{
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struct ctl_table *ipv6_table;
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struct ctl_table *ipv6_route_table;
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struct ctl_table *ipv6_icmp_table;
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int err;
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err = -ENOMEM;
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ipv6_table = kmemdup(ipv6_table_template, sizeof(ipv6_table_template),
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GFP_KERNEL);
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if (!ipv6_table)
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goto out;
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ipv6_table[0].data = &net->ipv6.sysctl.bindv6only;
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ipv6_table[1].data = &net->ipv6.sysctl.anycast_src_echo_reply;
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ipv6_table[2].data = &net->ipv6.sysctl.flowlabel_consistency;
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ipv6_table[3].data = &net->ipv6.sysctl.auto_flowlabels;
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ipv6_table[4].data = &net->ipv6.sysctl.fwmark_reflect;
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ipv6_table[5].data = &net->ipv6.sysctl.idgen_retries;
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ipv6_table[6].data = &net->ipv6.sysctl.idgen_delay;
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ipv6_table[7].data = &net->ipv6.sysctl.flowlabel_state_ranges;
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ipv6_table[8].data = &net->ipv6.sysctl.ip_nonlocal_bind;
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ipv6_table[9].data = &net->ipv6.sysctl.flowlabel_reflect;
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ipv6_table[10].data = &net->ipv6.sysctl.max_dst_opts_cnt;
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ipv6_table[11].data = &net->ipv6.sysctl.max_hbh_opts_cnt;
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ipv6_table[12].data = &net->ipv6.sysctl.max_dst_opts_len;
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ipv6_table[13].data = &net->ipv6.sysctl.max_hbh_opts_len;
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ipv6_table[14].data = &net->ipv6.sysctl.multipath_hash_policy,
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ipv6_table[15].data = &net->ipv6.sysctl.seg6_flowlabel;
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ipv6_route_table = ipv6_route_sysctl_init(net);
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if (!ipv6_route_table)
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goto out_ipv6_table;
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ipv6_icmp_table = ipv6_icmp_sysctl_init(net);
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if (!ipv6_icmp_table)
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goto out_ipv6_route_table;
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net->ipv6.sysctl.hdr = register_net_sysctl(net, "net/ipv6", ipv6_table);
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if (!net->ipv6.sysctl.hdr)
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goto out_ipv6_icmp_table;
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net->ipv6.sysctl.route_hdr =
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register_net_sysctl(net, "net/ipv6/route", ipv6_route_table);
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if (!net->ipv6.sysctl.route_hdr)
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goto out_unregister_ipv6_table;
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net->ipv6.sysctl.icmp_hdr =
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register_net_sysctl(net, "net/ipv6/icmp", ipv6_icmp_table);
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if (!net->ipv6.sysctl.icmp_hdr)
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goto out_unregister_route_table;
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err = 0;
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out:
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return err;
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out_unregister_route_table:
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unregister_net_sysctl_table(net->ipv6.sysctl.route_hdr);
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out_unregister_ipv6_table:
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unregister_net_sysctl_table(net->ipv6.sysctl.hdr);
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out_ipv6_icmp_table:
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kfree(ipv6_icmp_table);
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out_ipv6_route_table:
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kfree(ipv6_route_table);
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out_ipv6_table:
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kfree(ipv6_table);
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goto out;
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}
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static void __net_exit ipv6_sysctl_net_exit(struct net *net)
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{
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struct ctl_table *ipv6_table;
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struct ctl_table *ipv6_route_table;
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struct ctl_table *ipv6_icmp_table;
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ipv6_table = net->ipv6.sysctl.hdr->ctl_table_arg;
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ipv6_route_table = net->ipv6.sysctl.route_hdr->ctl_table_arg;
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ipv6_icmp_table = net->ipv6.sysctl.icmp_hdr->ctl_table_arg;
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unregister_net_sysctl_table(net->ipv6.sysctl.icmp_hdr);
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unregister_net_sysctl_table(net->ipv6.sysctl.route_hdr);
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unregister_net_sysctl_table(net->ipv6.sysctl.hdr);
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kfree(ipv6_table);
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kfree(ipv6_route_table);
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kfree(ipv6_icmp_table);
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}
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static struct pernet_operations ipv6_sysctl_net_ops = {
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.init = ipv6_sysctl_net_init,
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.exit = ipv6_sysctl_net_exit,
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};
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static struct ctl_table_header *ip6_header;
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int ipv6_sysctl_register(void)
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{
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int err = -ENOMEM;
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ip6_header = register_net_sysctl(&init_net, "net/ipv6", ipv6_rotable);
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if (!ip6_header)
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goto out;
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err = register_pernet_subsys(&ipv6_sysctl_net_ops);
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if (err)
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goto err_pernet;
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out:
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return err;
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err_pernet:
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unregister_net_sysctl_table(ip6_header);
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goto out;
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}
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void ipv6_sysctl_unregister(void)
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{
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unregister_net_sysctl_table(ip6_header);
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unregister_pernet_subsys(&ipv6_sysctl_net_ops);
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}
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