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linux-brain/net/ipv6/netfilter/ip6t_srh.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/* Kernel module to match Segment Routing Header (SRH) parameters. */
/* Author:
* Ahmed Abdelsalam <amsalam20@gmail.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <linux/types.h>
#include <net/ipv6.h>
#include <net/seg6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6t_srh.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
/* Test a struct->mt_invflags and a boolean for inequality */
#define NF_SRH_INVF(ptr, flag, boolean) \
((boolean) ^ !!((ptr)->mt_invflags & (flag)))
static bool srh_mt6(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct ip6t_srh *srhinfo = par->matchinfo;
struct ipv6_sr_hdr *srh;
struct ipv6_sr_hdr _srh;
int hdrlen, srhoff = 0;
if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, NULL) < 0)
return false;
srh = skb_header_pointer(skb, srhoff, sizeof(_srh), &_srh);
if (!srh)
return false;
hdrlen = ipv6_optlen(srh);
if (skb->len - srhoff < hdrlen)
return false;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
if (srh->segments_left > srh->first_segment)
return false;
/* Next Header matching */
if (srhinfo->mt_flags & IP6T_SRH_NEXTHDR)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_NEXTHDR,
!(srh->nexthdr == srhinfo->next_hdr)))
return false;
/* Header Extension Length matching */
if (srhinfo->mt_flags & IP6T_SRH_LEN_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_EQ,
!(srh->hdrlen == srhinfo->hdr_len)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LEN_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_GT,
!(srh->hdrlen > srhinfo->hdr_len)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LEN_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_LT,
!(srh->hdrlen < srhinfo->hdr_len)))
return false;
/* Segments Left matching */
if (srhinfo->mt_flags & IP6T_SRH_SEGS_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_EQ,
!(srh->segments_left == srhinfo->segs_left)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_SEGS_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_GT,
!(srh->segments_left > srhinfo->segs_left)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_SEGS_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_LT,
!(srh->segments_left < srhinfo->segs_left)))
return false;
/**
* Last Entry matching
* Last_Entry field was introduced in revision 6 of the SRH draft.
* It was called First_Segment in the previous revision
*/
if (srhinfo->mt_flags & IP6T_SRH_LAST_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_EQ,
!(srh->first_segment == srhinfo->last_entry)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LAST_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_GT,
!(srh->first_segment > srhinfo->last_entry)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LAST_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_LT,
!(srh->first_segment < srhinfo->last_entry)))
return false;
/**
* Tag matchig
* Tag field was introduced in revision 6 of the SRH draft.
*/
if (srhinfo->mt_flags & IP6T_SRH_TAG)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_TAG,
!(srh->tag == srhinfo->tag)))
return false;
return true;
}
static bool srh1_mt6(const struct sk_buff *skb, struct xt_action_param *par)
{
int hdrlen, psidoff, nsidoff, lsidoff, srhoff = 0;
const struct ip6t_srh1 *srhinfo = par->matchinfo;
struct in6_addr *psid, *nsid, *lsid;
struct in6_addr _psid, _nsid, _lsid;
struct ipv6_sr_hdr *srh;
struct ipv6_sr_hdr _srh;
if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, NULL) < 0)
return false;
srh = skb_header_pointer(skb, srhoff, sizeof(_srh), &_srh);
if (!srh)
return false;
hdrlen = ipv6_optlen(srh);
if (skb->len - srhoff < hdrlen)
return false;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
if (srh->segments_left > srh->first_segment)
return false;
/* Next Header matching */
if (srhinfo->mt_flags & IP6T_SRH_NEXTHDR)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_NEXTHDR,
!(srh->nexthdr == srhinfo->next_hdr)))
return false;
/* Header Extension Length matching */
if (srhinfo->mt_flags & IP6T_SRH_LEN_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_EQ,
!(srh->hdrlen == srhinfo->hdr_len)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LEN_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_GT,
!(srh->hdrlen > srhinfo->hdr_len)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LEN_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LEN_LT,
!(srh->hdrlen < srhinfo->hdr_len)))
return false;
/* Segments Left matching */
if (srhinfo->mt_flags & IP6T_SRH_SEGS_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_EQ,
!(srh->segments_left == srhinfo->segs_left)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_SEGS_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_GT,
!(srh->segments_left > srhinfo->segs_left)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_SEGS_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_SEGS_LT,
!(srh->segments_left < srhinfo->segs_left)))
return false;
/**
* Last Entry matching
* Last_Entry field was introduced in revision 6 of the SRH draft.
* It was called First_Segment in the previous revision
*/
if (srhinfo->mt_flags & IP6T_SRH_LAST_EQ)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_EQ,
!(srh->first_segment == srhinfo->last_entry)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LAST_GT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_GT,
!(srh->first_segment > srhinfo->last_entry)))
return false;
if (srhinfo->mt_flags & IP6T_SRH_LAST_LT)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LAST_LT,
!(srh->first_segment < srhinfo->last_entry)))
return false;
/**
* Tag matchig
* Tag field was introduced in revision 6 of the SRH draft
*/
if (srhinfo->mt_flags & IP6T_SRH_TAG)
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_TAG,
!(srh->tag == srhinfo->tag)))
return false;
/* Previous SID matching */
if (srhinfo->mt_flags & IP6T_SRH_PSID) {
if (srh->segments_left == srh->first_segment)
return false;
psidoff = srhoff + sizeof(struct ipv6_sr_hdr) +
((srh->segments_left + 1) * sizeof(struct in6_addr));
psid = skb_header_pointer(skb, psidoff, sizeof(_psid), &_psid);
if (!psid)
return false;
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_PSID,
ipv6_masked_addr_cmp(psid, &srhinfo->psid_msk,
&srhinfo->psid_addr)))
return false;
}
/* Next SID matching */
if (srhinfo->mt_flags & IP6T_SRH_NSID) {
if (srh->segments_left == 0)
return false;
nsidoff = srhoff + sizeof(struct ipv6_sr_hdr) +
((srh->segments_left - 1) * sizeof(struct in6_addr));
nsid = skb_header_pointer(skb, nsidoff, sizeof(_nsid), &_nsid);
if (!nsid)
return false;
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_NSID,
ipv6_masked_addr_cmp(nsid, &srhinfo->nsid_msk,
&srhinfo->nsid_addr)))
return false;
}
/* Last SID matching */
if (srhinfo->mt_flags & IP6T_SRH_LSID) {
lsidoff = srhoff + sizeof(struct ipv6_sr_hdr);
lsid = skb_header_pointer(skb, lsidoff, sizeof(_lsid), &_lsid);
if (!lsid)
return false;
if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LSID,
ipv6_masked_addr_cmp(lsid, &srhinfo->lsid_msk,
&srhinfo->lsid_addr)))
return false;
}
return true;
}
static int srh_mt6_check(const struct xt_mtchk_param *par)
{
const struct ip6t_srh *srhinfo = par->matchinfo;
if (srhinfo->mt_flags & ~IP6T_SRH_MASK) {
pr_info_ratelimited("unknown srh match flags %X\n",
srhinfo->mt_flags);
return -EINVAL;
}
if (srhinfo->mt_invflags & ~IP6T_SRH_INV_MASK) {
pr_info_ratelimited("unknown srh invflags %X\n",
srhinfo->mt_invflags);
return -EINVAL;
}
return 0;
}
static int srh1_mt6_check(const struct xt_mtchk_param *par)
{
const struct ip6t_srh1 *srhinfo = par->matchinfo;
if (srhinfo->mt_flags & ~IP6T_SRH_MASK) {
pr_info_ratelimited("unknown srh match flags %X\n",
srhinfo->mt_flags);
return -EINVAL;
}
if (srhinfo->mt_invflags & ~IP6T_SRH_INV_MASK) {
pr_info_ratelimited("unknown srh invflags %X\n",
srhinfo->mt_invflags);
return -EINVAL;
}
return 0;
}
static struct xt_match srh_mt6_reg[] __read_mostly = {
{
.name = "srh",
.revision = 0,
.family = NFPROTO_IPV6,
.match = srh_mt6,
.matchsize = sizeof(struct ip6t_srh),
.checkentry = srh_mt6_check,
.me = THIS_MODULE,
},
{
.name = "srh",
.revision = 1,
.family = NFPROTO_IPV6,
.match = srh1_mt6,
.matchsize = sizeof(struct ip6t_srh1),
.checkentry = srh1_mt6_check,
.me = THIS_MODULE,
}
};
static int __init srh_mt6_init(void)
{
return xt_register_matches(srh_mt6_reg, ARRAY_SIZE(srh_mt6_reg));
}
static void __exit srh_mt6_exit(void)
{
xt_unregister_matches(srh_mt6_reg, ARRAY_SIZE(srh_mt6_reg));
}
module_init(srh_mt6_init);
module_exit(srh_mt6_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Xtables: IPv6 Segment Routing Header match");
MODULE_AUTHOR("Ahmed Abdelsalam <amsalam20@gmail.com>");
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