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yaml
---
r: 6312
b: refs/heads/master
c: 1d3de41
h: refs/heads/master
v: v3
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Harald Welte authored and David S. Miller committed Aug 29, 2005
1 parent 6f3ab2a commit 1a3d9bd
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Showing 6 changed files with 225 additions and 4 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: e2e268665f6c01686b477a6b0cc5a70bab689d54
refs/heads/master: 1d3de414eb20d937d82c5219fd13ee4cedc499cb
16 changes: 13 additions & 3 deletions trunk/include/linux/dccp.h
Original file line number Diff line number Diff line change
Expand Up @@ -242,10 +242,15 @@ static inline struct dccp_hdr_ext *dccp_hdrx(const struct sk_buff *skb)
return (struct dccp_hdr_ext *)(skb->h.raw + sizeof(struct dccp_hdr));
}

static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
{
return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
}

static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
return __dccp_basic_hdr_len(dh);
}

static inline __u64 dccp_hdr_seq(const struct sk_buff *skb)
Expand Down Expand Up @@ -297,10 +302,15 @@ static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
return (struct dccp_hdr_reset *)(skb->h.raw + dccp_basic_hdr_len(skb));
}

static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh)
{
return __dccp_basic_hdr_len(dh) +
dccp_packet_hdr_len(dh->dccph_type);
}

static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
{
return dccp_basic_hdr_len(skb) +
dccp_packet_hdr_len(dccp_hdr(skb)->dccph_type);
return __dccp_hdr_len(dccp_hdr(skb));
}


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23 changes: 23 additions & 0 deletions trunk/include/linux/netfilter_ipv4/ipt_dccp.h
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@@ -0,0 +1,23 @@
#ifndef _IPT_DCCP_H_
#define _IPT_DCCP_H_

#define IPT_DCCP_SRC_PORTS 0x01
#define IPT_DCCP_DEST_PORTS 0x02
#define IPT_DCCP_TYPE 0x04
#define IPT_DCCP_OPTION 0x08

#define IPT_DCCP_VALID_FLAGS 0x0f

struct ipt_dccp_info {
u_int16_t dpts[2]; /* Min, Max */
u_int16_t spts[2]; /* Min, Max */

u_int16_t flags;
u_int16_t invflags;

u_int16_t typemask;
u_int8_t option;
};

#endif /* _IPT_DCCP_H_ */

11 changes: 11 additions & 0 deletions trunk/net/ipv4/netfilter/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -354,6 +354,17 @@ config IP_NF_MATCH_SCTP
If you want to compile it as a module, say M here and read
<file:Documentation/modules.txt>. If unsure, say `N'.

config IP_NF_MATCH_DCCP
tristate 'DCCP protocol match support'
depends on IP_NF_IPTABLES
help
With this option enabled, you will be able to use the iptables
`dccp' match in order to match on DCCP source/destination ports
and DCCP flags.

If you want to compile it as a module, say M here and read
<file:Documentation/modules.txt>. If unsure, say `N'.

config IP_NF_MATCH_COMMENT
tristate 'comment match support'
depends on IP_NF_IPTABLES
Expand Down
1 change: 1 addition & 0 deletions trunk/net/ipv4/netfilter/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ obj-$(CONFIG_IP_NF_MATCH_HELPER) += ipt_helper.o
obj-$(CONFIG_IP_NF_MATCH_LIMIT) += ipt_limit.o
obj-$(CONFIG_IP_NF_MATCH_HASHLIMIT) += ipt_hashlimit.o
obj-$(CONFIG_IP_NF_MATCH_SCTP) += ipt_sctp.o
obj-$(CONFIG_IP_NF_MATCH_DCCP) += ipt_dccp.o
obj-$(CONFIG_IP_NF_MATCH_MARK) += ipt_mark.o
obj-$(CONFIG_IP_NF_MATCH_MAC) += ipt_mac.o
obj-$(CONFIG_IP_NF_MATCH_IPRANGE) += ipt_iprange.o
Expand Down
176 changes: 176 additions & 0 deletions trunk/net/ipv4/netfilter/ipt_dccp.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,176 @@
/*
* iptables module for DCCP protocol header matching
*
* (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 <linux/spinlock.h>
#include <net/ip.h>
#include <linux/dccp.h>

#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_dccp.h>

#define DCCHECK(cond, option, flag, invflag) (!((flag) & (option)) \
|| (!!((invflag) & (option)) ^ (cond)))

static unsigned char *dccp_optbuf;
static DEFINE_SPINLOCK(dccp_buflock);

static inline int
dccp_find_option(u_int8_t option,
const struct sk_buff *skb,
const struct dccp_hdr *dh,
int *hotdrop)
{
/* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */
unsigned char *op;
unsigned int optoff = __dccp_hdr_len(dh);
unsigned int optlen = dh->dccph_doff*4 - __dccp_hdr_len(dh);
unsigned int i;

if (dh->dccph_doff * 4 < __dccp_hdr_len(dh)) {
*hotdrop = 1;
return 0;
}

if (!optlen)
return 0;

spin_lock_bh(&dccp_buflock);
op = skb_header_pointer(skb,
skb->nh.iph->ihl*4 + optoff,
optlen, dccp_optbuf);
if (op == NULL) {
/* If we don't have the whole header, drop packet. */
spin_unlock_bh(&dccp_buflock);
*hotdrop = 1;
return 0;
}

for (i = 0; i < optlen; ) {
if (op[i] == option) {
spin_unlock_bh(&dccp_buflock);
return 1;
}

if (op[i] < 2)
i++;
else
i += op[i+1]?:1;
}

spin_unlock_bh(&dccp_buflock);
return 0;
}


static inline int
match_types(const struct dccp_hdr *dh, u_int16_t typemask)
{
return (typemask & (1 << dh->dccph_type));
}

static inline int
match_option(u_int8_t option, const struct sk_buff *skb,
const struct dccp_hdr *dh, int *hotdrop)
{
return dccp_find_option(option, skb, dh, hotdrop);
}

static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
int *hotdrop)
{
const struct ipt_dccp_info *info =
(const struct ipt_dccp_info *)matchinfo;
struct dccp_hdr _dh, *dh;

if (offset)
return 0;

dh = skb_header_pointer(skb, skb->nh.iph->ihl*4, sizeof(_dh), &_dh);
if (dh == NULL) {
*hotdrop = 1;
return 0;
}

return DCCHECK(((ntohs(dh->dccph_sport) >= info->spts[0])
&& (ntohs(dh->dccph_sport) <= info->spts[1])),
IPT_DCCP_SRC_PORTS, info->flags, info->invflags)
&& DCCHECK(((ntohs(dh->dccph_dport) >= info->dpts[0])
&& (ntohs(dh->dccph_dport) <= info->dpts[1])),
IPT_DCCP_DEST_PORTS, info->flags, info->invflags)
&& DCCHECK(match_types(dh, info->typemask),
IPT_DCCP_TYPE, info->flags, info->invflags)
&& DCCHECK(match_option(info->option, skb, dh, hotdrop),
IPT_DCCP_OPTION, info->flags, info->invflags);
}

static int
checkentry(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
const struct ipt_dccp_info *info;

info = (const struct ipt_dccp_info *)matchinfo;

return ip->proto == IPPROTO_DCCP
&& !(ip->invflags & IPT_INV_PROTO)
&& matchsize == IPT_ALIGN(sizeof(struct ipt_dccp_info))
&& !(info->flags & ~IPT_DCCP_VALID_FLAGS)
&& !(info->invflags & ~IPT_DCCP_VALID_FLAGS)
&& !(info->invflags & ~info->flags);
}

static struct ipt_match dccp_match =
{
.name = "dccp",
.match = &match,
.checkentry = &checkentry,
.me = THIS_MODULE,
};

static int __init init(void)
{
int ret;

/* doff is 8 bits, so the maximum option size is (4*256). Don't put
* this in BSS since DaveM is worried about locked TLB's for kernel
* BSS. */
dccp_optbuf = kmalloc(256 * 4, GFP_KERNEL);
if (!dccp_optbuf)
return -ENOMEM;
ret = ipt_register_match(&dccp_match);
if (ret)
kfree(dccp_optbuf);

return ret;
}

static void __exit fini(void)
{
ipt_unregister_match(&dccp_match);
kfree(dccp_optbuf);
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("Match for DCCP protocol packets");

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