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![Ahmed Abdelsalam](/assets/img/avatar_default.png)
ECMP (equal-cost multipath) hashes are typically computed on the packets' 5-tuple(src IP, dst IP, src port, dst port, L4 proto). For encapsulated packets, the L4 data is not readily available and ECMP hashing will often revert to (src IP, dst IP). This will lead to traffic polarization on a single ECMP path, causing congestion and waste of network capacity. In IPv6, the 20-bit flow label field is also used as part of the ECMP hash. In the lack of L4 data, the hashing will be on (src IP, dst IP, flow label). Having a non-zero flow label is thus important for proper traffic load balancing when L4 data is unavailable (i.e., when packets are encapsulated). Currently, the seg6_do_srh_encap() function extracts the original packet's flow label and set it as the outer IPv6 flow label. There are two issues with this behaviour: a) There is no guarantee that the inner flow label is set by the source. b) If the original packet is not IPv6, the flow label will be set to zero (e.g., IPv4 or L2 encap). This patch adds a function, named seg6_make_flowlabel(), that computes a flow label from a given skb. It supports IPv6, IPv4 and L2 payloads, and leverages the per namespace 'seg6_flowlabel" sysctl value. The currently support behaviours are as follows: -1 set flowlabel to zero. 0 copy flowlabel from Inner paceket in case of Inner IPv6 (Set flowlabel to 0 in case IPv4/L2) 1 Compute the flowlabel using seg6_make_flowlabel() This patch has been tested for IPv6, IPv4, and L2 traffic. Signed-off-by: Ahmed Abdelsalam <amsalam20@gmail.com> Acked-by: David Lebrun <dlebrun@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
316 lines
7.9 KiB
C
316 lines
7.9 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 zero;
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static int one = 1;
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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,
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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 = &zero,
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.extra2 = &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 = &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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