/* Kernel module to match TCP MSS values. */

/* Copyright (C) 2000 Marc Boucher <marc@mbsi.ca>
 * Portions (C) 2005 by Harald Welte <laforge@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/skbuff.h>
#include <net/tcp.h>

#include <linux/netfilter/xt_tcpmss.h>
#include <linux/netfilter/x_tables.h>

#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
MODULE_DESCRIPTION("Xtables: TCP MSS match");
MODULE_ALIAS("ipt_tcpmss");
MODULE_ALIAS("ip6t_tcpmss");

static bool
tcpmss_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_tcpmss_match_info *info = par->matchinfo;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	/* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */
	const u_int8_t *op;
	u8 _opt[15 * 4 - sizeof(_tcph)];
	unsigned int i, optlen;

	/* If we don't have the whole header, drop packet. */
	th = skb_header_pointer(skb, par->thoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		goto dropit;

	/* Malformed. */
	if (th->doff*4 < sizeof(*th))
		goto dropit;

	optlen = th->doff*4 - sizeof(*th);
	if (!optlen)
		goto out;

	/* Truncated options. */
	op = skb_header_pointer(skb, par->thoff + sizeof(*th), optlen, _opt);
	if (op == NULL)
		goto dropit;

	for (i = 0; i < optlen; ) {
		if (op[i] == TCPOPT_MSS
		    && (optlen - i) >= TCPOLEN_MSS
		    && op[i+1] == TCPOLEN_MSS) {
			u_int16_t mssval;

			mssval = (op[i+2] << 8) | op[i+3];

			return (mssval >= info->mss_min &&
				mssval <= info->mss_max) ^ info->invert;
		}
		if (op[i] < 2)
			i++;
		else
			i += op[i+1] ? : 1;
	}
out:
	return info->invert;

dropit:
	par->hotdrop = true;
	return false;
}

static struct xt_match tcpmss_mt_reg[] __read_mostly = {
	{
		.name		= "tcpmss",
		.family		= NFPROTO_IPV4,
		.match		= tcpmss_mt,
		.matchsize	= sizeof(struct xt_tcpmss_match_info),
		.proto		= IPPROTO_TCP,
		.me		= THIS_MODULE,
	},
	{
		.name		= "tcpmss",
		.family		= NFPROTO_IPV6,
		.match		= tcpmss_mt,
		.matchsize	= sizeof(struct xt_tcpmss_match_info),
		.proto		= IPPROTO_TCP,
		.me		= THIS_MODULE,
	},
};

static int __init tcpmss_mt_init(void)
{
	return xt_register_matches(tcpmss_mt_reg, ARRAY_SIZE(tcpmss_mt_reg));
}

static void __exit tcpmss_mt_exit(void)
{
	xt_unregister_matches(tcpmss_mt_reg, ARRAY_SIZE(tcpmss_mt_reg));
}

module_init(tcpmss_mt_init);
module_exit(tcpmss_mt_exit);
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/rfkill?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>rfkill</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/rfkill/core.c?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>core.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='dd86e373e09fb16b83e8adf5c48c421a4ca76468'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Thomas Gleixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-31 23:58:38 +0100</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 08:37:27 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/rfkill/core.c?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>dd86e373e09fb16b83e8adf5c48c421a4ca76468</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/rfkill/core.c?id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>55703c2ea8584e303e342090614e0aab3509ab21</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/rfkill/core.c?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>net/rfkill/core.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/rfkill/core.c?h=nds-private-remove&amp;id=0b3589be9b98994ce3d5aeca52445d1f5627c4ba'>0b3589be9b98994ce3d5aeca52445d1f5627c4ba</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/rfkill/core.c?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468&amp;id2=0b3589be9b98994ce3d5aeca52445d1f5627c4ba'>diff</a>)</td></tr></table>
<div class='commit-subject'>perf/x86/intel/rapl: Make package handling more robust</div><div class='commit-msg'>The package management code in RAPL relies on package mapping being
available before a CPU is started. This changed with:

  9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")

because the ACPI/BIOS information turned out to be unreliable, but that
left RAPL in broken state. This was not noticed because on a regular boot
all CPUs are online before RAPL is initialized.

A possible fix would be to reintroduce the mess which allocates a package
data structure in CPU prepare and when it turns out to already exist in
starting throw it away later in the CPU online callback. But that's a
horrible hack and not required at all because RAPL becomes functional for
perf only in the CPU online callback. That's correct because user space is
not yet informed about the CPU being onlined, so nothing caan rely on RAPL
being available on that particular CPU.

Move the allocation to the CPU online callback and simplify the hotplug
handling. At this point the package mapping is established and correct.

This also adds a missing check for available package data in the
event_init() function.

Reported-by: Yasuaki Ishimatsu &lt;yasu.isimatu@gmail.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Vince Weaver &lt;vincent.weaver@maine.edu&gt;
Fixes: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")
Link: http://lkml.kernel.org/r/20170131230141.212593966@linutronix.de
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=dd86e373e09fb16b83e8adf5c48c421a4ca76468'>Diffstat</a> (limited to 'net/rfkill/core.c')</div><table summary='diffstat' class='diffstat'>