| Message ID | 1514545672-13827-1-git-send-email-amsalam20@gmail.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [net-next] netfilter: add segment routing header 'srh' match | expand |
On Fri, 29 Dec 2017 12:07:52 +0100 Ahmed Abdelsalam <amsalam20@gmail.com> wrote: > It allows matching packets based on Segment Routing Header > (SRH) information. > The implementation considers revision 7 of the SRH draft. > https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-07 > > Currently supported match options include: > (1) Next Header > (2) Hdr Ext Len > (3) Segments Left > (4) Last Entry > (5) Tag value of SRH > > Signed-off-by: Ahmed Abdelsalam <amsalam20@gmail.com> > --- > include/uapi/linux/netfilter_ipv6/ip6t_srh.h | 63 ++++++++++ > net/ipv6/netfilter/Kconfig | 9 ++ > net/ipv6/netfilter/Makefile | 1 + > net/ipv6/netfilter/ip6t_srh.c | 165 +++++++++++++++++++++++++++ > 4 files changed, 238 insertions(+) > create mode 100644 include/uapi/linux/netfilter_ipv6/ip6t_srh.h > create mode 100644 net/ipv6/netfilter/ip6t_srh.c > > diff --git a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > new file mode 100644 > index 0000000..1b5dbd8 > --- /dev/null > +++ b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > @@ -0,0 +1,63 @@ > +/** > + * Definitions for Segment Routing Header 'srh' match > + * > + * Author: > + * Ahmed Abdelsalam <amsalam20@gmail.com> > + */ > + > +#ifndef _IP6T_SRH_H > +#define _IP6T_SRH_H > + > +#include <linux/types.h> > +#include <linux/netfilter.h> > + > +/* Values for "mt_flags" field in struct ip6t_srh */ > +#define IP6T_SRH_NEXTHDR 0x0001 > +#define IP6T_SRH_LEN_EQ 0x0002 > +#define IP6T_SRH_LEN_GT 0x0004 > +#define IP6T_SRH_LEN_LT 0x0008 > +#define IP6T_SRH_SEGS_EQ 0x0010 > +#define IP6T_SRH_SEGS_GT 0x0020 > +#define IP6T_SRH_SEGS_LT 0x0040 > +#define IP6T_SRH_LAST_EQ 0x0080 > +#define IP6T_SRH_LAST_GT 0x0100 > +#define IP6T_SRH_LAST_LT 0x0200 > +#define IP6T_SRH_TAG 0x0400 > +#define IP6T_SRH_MASK 0x07FF > + > +/* Values for "mt_invflags" field in struct ip6t_srh */ > +#define IP6T_SRH_INV_NEXTHDR 0x0001 > +#define IP6T_SRH_INV_LEN_EQ 0x0002 > +#define IP6T_SRH_INV_LEN_GT 0x0004 > +#define IP6T_SRH_INV_LEN_LT 0x0008 > +#define IP6T_SRH_INV_SEGS_EQ 0x0010 > +#define IP6T_SRH_INV_SEGS_GT 0x0020 > +#define IP6T_SRH_INV_SEGS_LT 0x0040 > +#define IP6T_SRH_INV_LAST_EQ 0x0080 > +#define IP6T_SRH_INV_LAST_GT 0x0100 > +#define IP6T_SRH_INV_LAST_LT 0x0200 > +#define IP6T_SRH_INV_TAG 0x0400 > +#define IP6T_SRH_INV_MASK 0x07FF > + > +/** > + * struct ip6t_srh - SRH match options > + * @ next_hdr: Next header field of SRH > + * @ hdr_len: Extension header length field of SRH > + * @ segs_left: Segments left field of SRH > + * @ last_entry: Last entry field of SRH > + * @ tag: Tag field of SRH > + * @ mt_flags: match options > + * @ mt_invflags: Invert the sense of match options > + */ > + > +struct ip6t_srh { > + __u8 next_hdr; > + __u8 hdr_len; > + __u8 segs_left; > + __u8 last_entry; > + __u16 tag; > + __u16 mt_flags; > + __u16 mt_invflags; > +}; > + > +#endif /*_IP6T_SRH_H*/ > diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig > index 6acb2ee..e1818eb 100644 > --- a/net/ipv6/netfilter/Kconfig > +++ b/net/ipv6/netfilter/Kconfig > @@ -232,6 +232,15 @@ config IP6_NF_MATCH_RT > > To compile it as a module, choose M here. If unsure, say N. > > +config IP6_NF_MATCH_SRH > + tristate '"srh" Segment Routing header match support' > + depends on NETFILTER_ADVANCED > + help > + srh matching allows you to match packets based on the segment > + routing header of the packet. > + > + To compile it as a module, choose M here. If unsure, say N. > + > # The targets > config IP6_NF_TARGET_HL > tristate '"HL" hoplimit target support' > diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile > index c6ee0cd..e0d51a9 100644 > --- a/net/ipv6/netfilter/Makefile > +++ b/net/ipv6/netfilter/Makefile > @@ -54,6 +54,7 @@ obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o > obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o > obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o > obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o > +obj-$(CONFIG_IP6_NF_MATCH_SRH) += ip6t_srh.o > > # targets > obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o > diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c > new file mode 100644 > index 0000000..75e41dc9 > --- /dev/null > +++ b/net/ipv6/netfilter/ip6t_srh.c > @@ -0,0 +1,165 @@ > +/* > + * Kernel module to match Segment Routing Header (SRH) parameters. > + * > + * Author: > + * Ahmed Abdelsalam <amsalam20@gmail.com> > + * > + * > + * 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. > + */ > + > +#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> > + > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("Xtables: IPv6 Segment Routing Header match"); > +MODULE_AUTHOR("Ahmed Abdelsalam <amsalam20@gmail.com>"); > + > +/* 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 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_debug("unknown srh match flags %X\n", srhinfo->mt_flags); > + return -EINVAL; > + } > + > + if (srhinfo->mt_invflags & ~IP6T_SRH_INV_MASK) { > + pr_debug("unknown srh invflags %X\n", srhinfo->mt_invflags); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static struct xt_match srh_mt6_reg __read_mostly = { > + .name = "srh", > + .family = NFPROTO_IPV6, > + .match = srh_mt6, > + .matchsize = sizeof(struct ip6t_srh), > + .checkentry = srh_mt6_check, > + .me = THIS_MODULE, > +}; > + > +static int __init srh_mt6_init(void) > +{ > + return xt_register_match(&srh_mt6_reg); > +} > + > +static void __exit srh_mt6_exit(void) > +{ > + xt_unregister_match(&srh_mt6_reg); > +} > + > +module_init(srh_mt6_init); > +module_exit(srh_mt6_exit); > -- > 2.1.4 > David, Any comment on this patch ?
Hi Ahmed, On Fri, Dec 29, 2017 at 12:07:52PM +0100, Ahmed Abdelsalam wrote: > It allows matching packets based on Segment Routing Header > (SRH) information. > The implementation considers revision 7 of the SRH draft. > https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-07 > > Currently supported match options include: > (1) Next Header > (2) Hdr Ext Len > (3) Segments Left > (4) Last Entry > (5) Tag value of SRH > > Signed-off-by: Ahmed Abdelsalam <amsalam20@gmail.com> > --- > include/uapi/linux/netfilter_ipv6/ip6t_srh.h | 63 ++++++++++ > net/ipv6/netfilter/Kconfig | 9 ++ > net/ipv6/netfilter/Makefile | 1 + > net/ipv6/netfilter/ip6t_srh.c | 165 +++++++++++++++++++++++++++ > 4 files changed, 238 insertions(+) > create mode 100644 include/uapi/linux/netfilter_ipv6/ip6t_srh.h > create mode 100644 net/ipv6/netfilter/ip6t_srh.c > > diff --git a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > new file mode 100644 > index 0000000..1b5dbd8 > --- /dev/null > +++ b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > @@ -0,0 +1,63 @@ > +/** > + * Definitions for Segment Routing Header 'srh' match > + * > + * Author: > + * Ahmed Abdelsalam <amsalam20@gmail.com> > + */ Please, add this in SPDX format instead. See include/uapi/linux/netfilter/xt_owner.h for instance. > +#ifndef _IP6T_SRH_H > +#define _IP6T_SRH_H > + > +#include <linux/types.h> > +#include <linux/netfilter.h> > + > +/* Values for "mt_flags" field in struct ip6t_srh */ > +#define IP6T_SRH_NEXTHDR 0x0001 > +#define IP6T_SRH_LEN_EQ 0x0002 > +#define IP6T_SRH_LEN_GT 0x0004 > +#define IP6T_SRH_LEN_LT 0x0008 > +#define IP6T_SRH_SEGS_EQ 0x0010 > +#define IP6T_SRH_SEGS_GT 0x0020 > +#define IP6T_SRH_SEGS_LT 0x0040 > +#define IP6T_SRH_LAST_EQ 0x0080 > +#define IP6T_SRH_LAST_GT 0x0100 > +#define IP6T_SRH_LAST_LT 0x0200 > +#define IP6T_SRH_TAG 0x0400 > +#define IP6T_SRH_MASK 0x07FF > + > +/* Values for "mt_invflags" field in struct ip6t_srh */ > +#define IP6T_SRH_INV_NEXTHDR 0x0001 > +#define IP6T_SRH_INV_LEN_EQ 0x0002 > +#define IP6T_SRH_INV_LEN_GT 0x0004 > +#define IP6T_SRH_INV_LEN_LT 0x0008 > +#define IP6T_SRH_INV_SEGS_EQ 0x0010 > +#define IP6T_SRH_INV_SEGS_GT 0x0020 > +#define IP6T_SRH_INV_SEGS_LT 0x0040 > +#define IP6T_SRH_INV_LAST_EQ 0x0080 > +#define IP6T_SRH_INV_LAST_GT 0x0100 > +#define IP6T_SRH_INV_LAST_LT 0x0200 > +#define IP6T_SRH_INV_TAG 0x0400 > +#define IP6T_SRH_INV_MASK 0x07FF Looking at all these EQ, GT, LT... I think this should be very easy to implement in nf_tables with no kernel changes. You only need to add the protocol definition to: nftables/src/exthdr.c Would you have a look into this? This would be very much appreciated to we keep nftables in sync with what we have in iptables. > + > +/** > + * struct ip6t_srh - SRH match options > + * @ next_hdr: Next header field of SRH > + * @ hdr_len: Extension header length field of SRH > + * @ segs_left: Segments left field of SRH > + * @ last_entry: Last entry field of SRH > + * @ tag: Tag field of SRH > + * @ mt_flags: match options > + * @ mt_invflags: Invert the sense of match options > + */ > + > +struct ip6t_srh { > + __u8 next_hdr; > + __u8 hdr_len; > + __u8 segs_left; > + __u8 last_entry; > + __u16 tag; > + __u16 mt_flags; > + __u16 mt_invflags; > +}; > + > +#endif /*_IP6T_SRH_H*/ > diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig > index 6acb2ee..e1818eb 100644 > --- a/net/ipv6/netfilter/Kconfig > +++ b/net/ipv6/netfilter/Kconfig > @@ -232,6 +232,15 @@ config IP6_NF_MATCH_RT > > To compile it as a module, choose M here. If unsure, say N. > > +config IP6_NF_MATCH_SRH > + tristate '"srh" Segment Routing header match support' > + depends on NETFILTER_ADVANCED > + help > + srh matching allows you to match packets based on the segment > + routing header of the packet. > + > + To compile it as a module, choose M here. If unsure, say N. > + > # The targets > config IP6_NF_TARGET_HL > tristate '"HL" hoplimit target support' > diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile > index c6ee0cd..e0d51a9 100644 > --- a/net/ipv6/netfilter/Makefile > +++ b/net/ipv6/netfilter/Makefile > @@ -54,6 +54,7 @@ obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o > obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o > obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o > obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o > +obj-$(CONFIG_IP6_NF_MATCH_SRH) += ip6t_srh.o > > # targets > obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o > diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c > new file mode 100644 > index 0000000..75e41dc9 > --- /dev/null > +++ b/net/ipv6/netfilter/ip6t_srh.c > @@ -0,0 +1,165 @@ > +/* > + * Kernel module to match Segment Routing Header (SRH) parameters. > + * > + * Author: > + * Ahmed Abdelsalam <amsalam20@gmail.com> > + * > + * > + * 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. > + */ > + > +#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> > + > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("Xtables: IPv6 Segment Routing Header match"); > +MODULE_AUTHOR("Ahmed Abdelsalam <amsalam20@gmail.com>"); Not a deal breaker, but modern code usually places these MODULE_* lines at the end of the file. > + > +/* 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); > + Remove unnecessary line break. > + 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 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_debug("unknown srh match flags %X\n", srhinfo->mt_flags); Better call pr_err() here. I know we don't do this in other extensions, but we should not use pr_debug() for this. ip6tables explicit refers to 'dmesg' when -EINVAL is returned. Thanks. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, 7 Jan 2018 00:40:03 +0100 Pablo Neira Ayuso <pablo@netfilter.org> wrote: > Hi Ahmed, > > On Fri, Dec 29, 2017 at 12:07:52PM +0100, Ahmed Abdelsalam wrote: > > It allows matching packets based on Segment Routing Header > > (SRH) information. > > The implementation considers revision 7 of the SRH draft. > > https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-07 > > > > Currently supported match options include: > > (1) Next Header > > (2) Hdr Ext Len > > (3) Segments Left > > (4) Last Entry > > (5) Tag value of SRH > > > > Signed-off-by: Ahmed Abdelsalam <amsalam20@gmail.com> > > --- > > include/uapi/linux/netfilter_ipv6/ip6t_srh.h | 63 ++++++++++ > > net/ipv6/netfilter/Kconfig | 9 ++ > > net/ipv6/netfilter/Makefile | 1 + > > net/ipv6/netfilter/ip6t_srh.c | 165 +++++++++++++++++++++++++++ > > 4 files changed, 238 insertions(+) > > create mode 100644 include/uapi/linux/netfilter_ipv6/ip6t_srh.h > > create mode 100644 net/ipv6/netfilter/ip6t_srh.c > > > > diff --git a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > > new file mode 100644 > > index 0000000..1b5dbd8 > > --- /dev/null > > +++ b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h > > @@ -0,0 +1,63 @@ > > +/** > > + * Definitions for Segment Routing Header 'srh' match > > + * > > + * Author: > > + * Ahmed Abdelsalam <amsalam20@gmail.com> > > + */ > > Please, add this in SPDX format instead. > > See include/uapi/linux/netfilter/xt_owner.h for instance. > Ok > > +#ifndef _IP6T_SRH_H > > +#define _IP6T_SRH_H > > + > > +#include <linux/types.h> > > +#include <linux/netfilter.h> > > + > > +/* Values for "mt_flags" field in struct ip6t_srh */ > > +#define IP6T_SRH_NEXTHDR 0x0001 > > +#define IP6T_SRH_LEN_EQ 0x0002 > > +#define IP6T_SRH_LEN_GT 0x0004 > > +#define IP6T_SRH_LEN_LT 0x0008 > > +#define IP6T_SRH_SEGS_EQ 0x0010 > > +#define IP6T_SRH_SEGS_GT 0x0020 > > +#define IP6T_SRH_SEGS_LT 0x0040 > > +#define IP6T_SRH_LAST_EQ 0x0080 > > +#define IP6T_SRH_LAST_GT 0x0100 > > +#define IP6T_SRH_LAST_LT 0x0200 > > +#define IP6T_SRH_TAG 0x0400 > > +#define IP6T_SRH_MASK 0x07FF > > + > > +/* Values for "mt_invflags" field in struct ip6t_srh */ > > +#define IP6T_SRH_INV_NEXTHDR 0x0001 > > +#define IP6T_SRH_INV_LEN_EQ 0x0002 > > +#define IP6T_SRH_INV_LEN_GT 0x0004 > > +#define IP6T_SRH_INV_LEN_LT 0x0008 > > +#define IP6T_SRH_INV_SEGS_EQ 0x0010 > > +#define IP6T_SRH_INV_SEGS_GT 0x0020 > > +#define IP6T_SRH_INV_SEGS_LT 0x0040 > > +#define IP6T_SRH_INV_LAST_EQ 0x0080 > > +#define IP6T_SRH_INV_LAST_GT 0x0100 > > +#define IP6T_SRH_INV_LAST_LT 0x0200 > > +#define IP6T_SRH_INV_TAG 0x0400 > > +#define IP6T_SRH_INV_MASK 0x07FF > > Looking at all these EQ, GT, LT... I think this should be very easy to > implement in nf_tables with no kernel changes. > > You only need to add the protocol definition to: > > nftables/src/exthdr.c > > Would you have a look into this? This would be very much appreciated > to we keep nftables in sync with what we have in iptables. Yes, I look into it. I will send you a patch for nf_tables as well. > > > + > > +/** > > + * struct ip6t_srh - SRH match options > > + * @ next_hdr: Next header field of SRH > > + * @ hdr_len: Extension header length field of SRH > > + * @ segs_left: Segments left field of SRH > > + * @ last_entry: Last entry field of SRH > > + * @ tag: Tag field of SRH > > + * @ mt_flags: match options > > + * @ mt_invflags: Invert the sense of match options > > + */ > > + > > +struct ip6t_srh { > > + __u8 next_hdr; > > + __u8 hdr_len; > > + __u8 segs_left; > > + __u8 last_entry; > > + __u16 tag; > > + __u16 mt_flags; > > + __u16 mt_invflags; > > +}; > > + > > +#endif /*_IP6T_SRH_H*/ > > diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig > > index 6acb2ee..e1818eb 100644 > > --- a/net/ipv6/netfilter/Kconfig > > +++ b/net/ipv6/netfilter/Kconfig > > @@ -232,6 +232,15 @@ config IP6_NF_MATCH_RT > > > > To compile it as a module, choose M here. If unsure, say N. > > > > +config IP6_NF_MATCH_SRH > > + tristate '"srh" Segment Routing header match support' > > + depends on NETFILTER_ADVANCED > > + help > > + srh matching allows you to match packets based on the segment > > + routing header of the packet. > > + > > + To compile it as a module, choose M here. If unsure, say N. > > + > > # The targets > > config IP6_NF_TARGET_HL > > tristate '"HL" hoplimit target support' > > diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile > > index c6ee0cd..e0d51a9 100644 > > --- a/net/ipv6/netfilter/Makefile > > +++ b/net/ipv6/netfilter/Makefile > > @@ -54,6 +54,7 @@ obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o > > obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o > > obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o > > obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o > > +obj-$(CONFIG_IP6_NF_MATCH_SRH) += ip6t_srh.o > > > > # targets > > obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o > > diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c > > new file mode 100644 > > index 0000000..75e41dc9 > > --- /dev/null > > +++ b/net/ipv6/netfilter/ip6t_srh.c > > @@ -0,0 +1,165 @@ > > +/* > > + * Kernel module to match Segment Routing Header (SRH) parameters. > > + * > > + * Author: > > + * Ahmed Abdelsalam <amsalam20@gmail.com> > > + * > > + * > > + * 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. > > + */ > > + > > +#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> > > + > > +MODULE_LICENSE("GPL"); > > +MODULE_DESCRIPTION("Xtables: IPv6 Segment Routing Header match"); > > +MODULE_AUTHOR("Ahmed Abdelsalam <amsalam20@gmail.com>"); > > Not a deal breaker, but modern code usually places these MODULE_* > lines at the end of the file. > I will move them to the end. > > + > > +/* 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); > > + > > Remove unnecessary line break. > Ok > > + 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 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_debug("unknown srh match flags %X\n", srhinfo->mt_flags); > > Better call pr_err() here. I know we don't do this in other > extensions, but we should not use pr_debug() for this. ip6tables > explicit refers to 'dmesg' when -EINVAL is returned. > I will change this one also . > Thanks. I will send a new pacth addressing these comments. Thanks
diff --git a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h new file mode 100644 index 0000000..1b5dbd8 --- /dev/null +++ b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h @@ -0,0 +1,63 @@ +/** + * Definitions for Segment Routing Header 'srh' match + * + * Author: + * Ahmed Abdelsalam <amsalam20@gmail.com> + */ + +#ifndef _IP6T_SRH_H +#define _IP6T_SRH_H + +#include <linux/types.h> +#include <linux/netfilter.h> + +/* Values for "mt_flags" field in struct ip6t_srh */ +#define IP6T_SRH_NEXTHDR 0x0001 +#define IP6T_SRH_LEN_EQ 0x0002 +#define IP6T_SRH_LEN_GT 0x0004 +#define IP6T_SRH_LEN_LT 0x0008 +#define IP6T_SRH_SEGS_EQ 0x0010 +#define IP6T_SRH_SEGS_GT 0x0020 +#define IP6T_SRH_SEGS_LT 0x0040 +#define IP6T_SRH_LAST_EQ 0x0080 +#define IP6T_SRH_LAST_GT 0x0100 +#define IP6T_SRH_LAST_LT 0x0200 +#define IP6T_SRH_TAG 0x0400 +#define IP6T_SRH_MASK 0x07FF + +/* Values for "mt_invflags" field in struct ip6t_srh */ +#define IP6T_SRH_INV_NEXTHDR 0x0001 +#define IP6T_SRH_INV_LEN_EQ 0x0002 +#define IP6T_SRH_INV_LEN_GT 0x0004 +#define IP6T_SRH_INV_LEN_LT 0x0008 +#define IP6T_SRH_INV_SEGS_EQ 0x0010 +#define IP6T_SRH_INV_SEGS_GT 0x0020 +#define IP6T_SRH_INV_SEGS_LT 0x0040 +#define IP6T_SRH_INV_LAST_EQ 0x0080 +#define IP6T_SRH_INV_LAST_GT 0x0100 +#define IP6T_SRH_INV_LAST_LT 0x0200 +#define IP6T_SRH_INV_TAG 0x0400 +#define IP6T_SRH_INV_MASK 0x07FF + +/** + * struct ip6t_srh - SRH match options + * @ next_hdr: Next header field of SRH + * @ hdr_len: Extension header length field of SRH + * @ segs_left: Segments left field of SRH + * @ last_entry: Last entry field of SRH + * @ tag: Tag field of SRH + * @ mt_flags: match options + * @ mt_invflags: Invert the sense of match options + */ + +struct ip6t_srh { + __u8 next_hdr; + __u8 hdr_len; + __u8 segs_left; + __u8 last_entry; + __u16 tag; + __u16 mt_flags; + __u16 mt_invflags; +}; + +#endif /*_IP6T_SRH_H*/ diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig index 6acb2ee..e1818eb 100644 --- a/net/ipv6/netfilter/Kconfig +++ b/net/ipv6/netfilter/Kconfig @@ -232,6 +232,15 @@ config IP6_NF_MATCH_RT To compile it as a module, choose M here. If unsure, say N. +config IP6_NF_MATCH_SRH + tristate '"srh" Segment Routing header match support' + depends on NETFILTER_ADVANCED + help + srh matching allows you to match packets based on the segment + routing header of the packet. + + To compile it as a module, choose M here. If unsure, say N. + # The targets config IP6_NF_TARGET_HL tristate '"HL" hoplimit target support' diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile index c6ee0cd..e0d51a9 100644 --- a/net/ipv6/netfilter/Makefile +++ b/net/ipv6/netfilter/Makefile @@ -54,6 +54,7 @@ obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o +obj-$(CONFIG_IP6_NF_MATCH_SRH) += ip6t_srh.o # targets obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c new file mode 100644 index 0000000..75e41dc9 --- /dev/null +++ b/net/ipv6/netfilter/ip6t_srh.c @@ -0,0 +1,165 @@ +/* + * Kernel module to match Segment Routing Header (SRH) parameters. + * + * Author: + * Ahmed Abdelsalam <amsalam20@gmail.com> + * + * + * 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. + */ + +#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> + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Xtables: IPv6 Segment Routing Header match"); +MODULE_AUTHOR("Ahmed Abdelsalam <amsalam20@gmail.com>"); + +/* 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 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_debug("unknown srh match flags %X\n", srhinfo->mt_flags); + return -EINVAL; + } + + if (srhinfo->mt_invflags & ~IP6T_SRH_INV_MASK) { + pr_debug("unknown srh invflags %X\n", srhinfo->mt_invflags); + return -EINVAL; + } + + return 0; +} + +static struct xt_match srh_mt6_reg __read_mostly = { + .name = "srh", + .family = NFPROTO_IPV6, + .match = srh_mt6, + .matchsize = sizeof(struct ip6t_srh), + .checkentry = srh_mt6_check, + .me = THIS_MODULE, +}; + +static int __init srh_mt6_init(void) +{ + return xt_register_match(&srh_mt6_reg); +} + +static void __exit srh_mt6_exit(void) +{ + xt_unregister_match(&srh_mt6_reg); +} + +module_init(srh_mt6_init); +module_exit(srh_mt6_exit);
It allows matching packets based on Segment Routing Header (SRH) information. The implementation considers revision 7 of the SRH draft. https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-07 Currently supported match options include: (1) Next Header (2) Hdr Ext Len (3) Segments Left (4) Last Entry (5) Tag value of SRH Signed-off-by: Ahmed Abdelsalam <amsalam20@gmail.com> --- include/uapi/linux/netfilter_ipv6/ip6t_srh.h | 63 ++++++++++ net/ipv6/netfilter/Kconfig | 9 ++ net/ipv6/netfilter/Makefile | 1 + net/ipv6/netfilter/ip6t_srh.c | 165 +++++++++++++++++++++++++++ 4 files changed, 238 insertions(+) create mode 100644 include/uapi/linux/netfilter_ipv6/ip6t_srh.h create mode 100644 net/ipv6/netfilter/ip6t_srh.c