[NETFITLER]: Add nfnetlink layer.
Introduce "nfnetlink" (netfilter netlink) layer. This layer is used as transport layer for all userspace communication of the new upcoming netfilter subsystems, such as ctnetlink, nfnetlink_queue and some day even the mythical pkttables ;) Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Harald Welte
David S. Miller
Родитель
ac3247baf8
Коммит
f9e815b376
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@ -0,0 +1,145 @@
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#ifndef _NFNETLINK_H
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#define _NFNETLINK_H
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#include <linux/types.h>
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/* nfnetlink groups: Up to 32 maximum */
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#define NF_NETLINK_CONNTRACK_NEW 0x00000001
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#define NF_NETLINK_CONNTRACK_UPDATE 0x00000002
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#define NF_NETLINK_CONNTRACK_DESTROY 0x00000004
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#define NF_NETLINK_CONNTRACK_EXP_NEW 0x00000008
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#define NF_NETLINK_CONNTRACK_EXP_UPDATE 0x00000010
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#define NF_NETLINK_CONNTRACK_EXP_DESTROY 0x00000020
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/* Generic structure for encapsulation optional netfilter information.
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* It is reminiscent of sockaddr, but with sa_family replaced
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* with attribute type.
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* ! This should someday be put somewhere generic as now rtnetlink and
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* ! nfnetlink use the same attributes methods. - J. Schulist.
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*/
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struct nfattr
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{
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u_int16_t nfa_len;
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u_int16_t nfa_type;
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} __attribute__ ((packed));
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/* FIXME: Shamelessly copy and pasted from rtnetlink.h, it's time
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* to put this in a generic file */
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#define NFA_ALIGNTO 4
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#define NFA_ALIGN(len) (((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1))
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#define NFA_OK(nfa,len) ((len) > 0 && (nfa)->nfa_len >= sizeof(struct nfattr) \
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&& (nfa)->nfa_len <= (len))
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#define NFA_NEXT(nfa,attrlen) ((attrlen) -= NFA_ALIGN((nfa)->nfa_len), \
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(struct nfattr *)(((char *)(nfa)) + NFA_ALIGN((nfa)->nfa_len)))
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#define NFA_LENGTH(len) (NFA_ALIGN(sizeof(struct nfattr)) + (len))
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#define NFA_SPACE(len) NFA_ALIGN(NFA_LENGTH(len))
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#define NFA_DATA(nfa) ((void *)(((char *)(nfa)) + NFA_LENGTH(0)))
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#define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0))
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#define NFA_NEST(skb, type) \
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({ struct nfattr *__start = (struct nfattr *) (skb)->tail; \
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NFA_PUT(skb, type, 0, NULL); \
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__start; })
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#define NFA_NEST_END(skb, start) \
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({ (start)->nfa_len = ((skb)->tail - (unsigned char *) (start)); \
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(skb)->len; })
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#define NFA_NEST_CANCEL(skb, start) \
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({ if (start) \
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skb_trim(skb, (unsigned char *) (start) - (skb)->data); \
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-1; })
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/* General form of address family dependent message.
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*/
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struct nfgenmsg {
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u_int8_t nfgen_family; /* AF_xxx */
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u_int8_t version; /* nfnetlink version */
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u_int16_t res_id; /* resource id */
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} __attribute__ ((packed));
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#define NFNETLINK_V1 1
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#define NFM_NFA(n) ((struct nfattr *)(((char *)(n)) \
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+ NLMSG_ALIGN(sizeof(struct nfgenmsg))))
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#define NFM_PAYLOAD(n) NLMSG_PAYLOAD(n, sizeof(struct nfgenmsg))
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/* netfilter netlink message types are split in two pieces:
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* 8 bit subsystem, 8bit operation.
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*/
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#define NFNL_SUBSYS_ID(x) ((x & 0xff00) >> 8)
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#define NFNL_MSG_TYPE(x) (x & 0x00ff)
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enum nfnl_subsys_id {
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NFNL_SUBSYS_NONE = 0,
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NFNL_SUBSYS_CTNETLINK,
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NFNL_SUBSYS_CTNETLINK_EXP,
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NFNL_SUBSYS_IPTNETLINK,
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NFNL_SUBSYS_QUEUE,
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NFNL_SUBSYS_ULOG,
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NFNL_SUBSYS_COUNT,
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};
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#ifdef __KERNEL__
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#include <linux/capability.h>
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struct nfnl_callback
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{
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kernel_cap_t cap_required; /* capabilities required for this msg */
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int (*call)(struct sock *nl, struct sk_buff *skb,
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struct nlmsghdr *nlh, struct nfattr *cda[], int *errp);
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};
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struct nfnetlink_subsystem
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{
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const char *name;
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__u8 subsys_id; /* nfnetlink subsystem ID */
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__u8 cb_count; /* number of callbacks */
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u_int32_t attr_count; /* number of nfattr's */
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struct nfnl_callback *cb; /* callback for individual types */
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};
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extern void __nfa_fill(struct sk_buff *skb, int attrtype,
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int attrlen, const void *data);
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#define NFA_PUT(skb, attrtype, attrlen, data) \
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({ if (skb_tailroom(skb) < (int)NFA_SPACE(attrlen)) goto nfattr_failure; \
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__nfa_fill(skb, attrtype, attrlen, data); })
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extern struct semaphore nfnl_sem;
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#define nfnl_shlock() down(&nfnl_sem)
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#define nfnl_shlock_nowait() down_trylock(&nfnl_sem)
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#define nfnl_shunlock() do { up(&nfnl_sem); \
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if(nfnl && nfnl->sk_receive_queue.qlen) \
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nfnl->sk_data_ready(nfnl, 0); \
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} while(0)
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extern void nfnl_lock(void);
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extern void nfnl_unlock(void);
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extern int nfnetlink_subsys_register(struct nfnetlink_subsystem *n);
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extern int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n);
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extern int nfattr_parse(struct nfattr *tb[], int maxattr,
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struct nfattr *nfa, int len);
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#define nfattr_parse_nested(tb, max, nfa) \
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nfattr_parse((tb), (max), NFA_DATA((nfa)), NFA_PAYLOAD((nfa)))
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#define nfattr_bad_size(tb, max, cta_min) \
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({ int __i, __res = 0; \
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for (__i=0; __i<max; __i++) \
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if (tb[__i] && NFA_PAYLOAD(tb[__i]) < cta_min[__i]){ \
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__res = 1; \
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break; \
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} \
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__res; \
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})
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extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group,
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int echo);
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extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags);
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#endif /* __KERNEL__ */
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#endif /* _NFNETLINK_H */
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@ -205,6 +205,8 @@ config NET_PKTGEN
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To compile this code as a module, choose M here: the
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module will be called pktgen.
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source "net/netfilter/Kconfig"
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endmenu
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endmenu
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@ -16,6 +16,7 @@ obj-$(CONFIG_NET) += $(tmp-y)
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obj-$(CONFIG_LLC) += llc/
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obj-$(CONFIG_NET) += ethernet/ 802/ sched/ netlink/
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obj-$(CONFIG_INET) += ipv4/
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obj-$(CONFIG_NETFILTER) += netfilter/
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obj-$(CONFIG_XFRM) += xfrm/
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obj-$(CONFIG_UNIX) += unix/
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ifneq ($(CONFIG_IPV6),)
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@ -0,0 +1,5 @@
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config NETFILTER_NETLINK
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tristate "Netfilter netlink interface"
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help
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If this option is enabled, the kernel will include support
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for the new netfilter netlink interface.
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@ -0,0 +1 @@
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obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o
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@ -0,0 +1,343 @@
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/* Netfilter messages via netlink socket. Allows for user space
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* protocol helpers and general trouble making from userspace.
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*
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* (C) 2001 by Jay Schulist <jschlst@samba.org>,
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* (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
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* (C) 2005 by Pablo Neira Ayuso <pablo@eurodev.net>
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*
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* Initial netfilter messages via netlink development funded and
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* generally made possible by Network Robots, Inc. (www.networkrobots.com)
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*
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* Further development of this code funded by Astaro AG (http://www.astaro.com)
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*
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* This software may be used and distributed according to the terms
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* of the GNU General Public License, incorporated herein by reference.
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/kernel.h>
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#include <linux/major.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <linux/fcntl.h>
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#include <linux/skbuff.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <net/sock.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/netfilter.h>
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#include <linux/netlink.h>
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#include <linux/netfilter/nfnetlink.h>
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MODULE_LICENSE("GPL");
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static char __initdata nfversion[] = "0.30";
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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static struct sock *nfnl = NULL;
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static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
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DECLARE_MUTEX(nfnl_sem);
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void nfnl_lock(void)
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{
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nfnl_shlock();
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}
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void nfnl_unlock(void)
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{
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nfnl_shunlock();
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}
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int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
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{
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DEBUGP("registering subsystem ID %u\n", n->subsys_id);
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/* If the netlink socket wasn't created, then fail */
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if (!nfnl)
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return -1;
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nfnl_lock();
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subsys_table[n->subsys_id] = n;
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nfnl_unlock();
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return 0;
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}
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int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n)
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{
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DEBUGP("unregistering subsystem ID %u\n", n->subsys_id);
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nfnl_lock();
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subsys_table[n->subsys_id] = NULL;
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nfnl_unlock();
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return 0;
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}
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static inline struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
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{
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u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
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if (subsys_id >= NFNL_SUBSYS_COUNT
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|| subsys_table[subsys_id] == NULL)
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return NULL;
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return subsys_table[subsys_id];
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}
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static inline struct nfnl_callback *
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nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss)
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{
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u_int8_t cb_id = NFNL_MSG_TYPE(type);
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if (cb_id >= ss->cb_count) {
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DEBUGP("msgtype %u >= %u, returning\n", type, ss->cb_count);
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return NULL;
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}
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return &ss->cb[cb_id];
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}
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void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
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const void *data)
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{
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struct nfattr *nfa;
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int size = NFA_LENGTH(attrlen);
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nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
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nfa->nfa_type = attrtype;
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nfa->nfa_len = size;
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memcpy(NFA_DATA(nfa), data, attrlen);
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}
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int nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len)
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{
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memset(tb, 0, sizeof(struct nfattr *) * maxattr);
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while (NFA_OK(nfa, len)) {
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unsigned flavor = nfa->nfa_type;
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if (flavor && flavor <= maxattr)
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tb[flavor-1] = nfa;
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nfa = NFA_NEXT(nfa, len);
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}
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return 0;
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}
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/**
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* nfnetlink_check_attributes - check and parse nfnetlink attributes
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*
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* subsys: nfnl subsystem for which this message is to be parsed
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* nlmsghdr: netlink message to be checked/parsed
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* cda: array of pointers, needs to be at least subsys->attr_count big
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*
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*/
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static int
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nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
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struct nlmsghdr *nlh, struct nfattr *cda[])
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{
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int min_len;
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memset(cda, 0, sizeof(struct nfattr *) * subsys->attr_count);
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/* check attribute lengths. */
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min_len = NLMSG_ALIGN(sizeof(struct nfgenmsg));
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if (nlh->nlmsg_len < min_len)
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return -EINVAL;
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if (nlh->nlmsg_len > min_len) {
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struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
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int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
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while (NFA_OK(attr, attrlen)) {
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unsigned flavor = attr->nfa_type;
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if (flavor) {
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if (flavor > subsys->attr_count)
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return -EINVAL;
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cda[flavor - 1] = attr;
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}
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attr = NFA_NEXT(attr, attrlen);
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}
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} else
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return -EINVAL;
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return 0;
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}
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int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
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{
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int allocation = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
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int err = 0;
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NETLINK_CB(skb).dst_groups = group;
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if (echo)
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atomic_inc(&skb->users);
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netlink_broadcast(nfnl, skb, pid, group, allocation);
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if (echo)
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err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT);
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return err;
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}
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int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
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{
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return netlink_unicast(nfnl, skb, pid, flags);
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}
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/* Process one complete nfnetlink message. */
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static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
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struct nlmsghdr *nlh, int *errp)
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{
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struct nfnl_callback *nc;
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struct nfnetlink_subsystem *ss;
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int type, err = 0;
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DEBUGP("entered; subsys=%u, msgtype=%u\n",
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NFNL_SUBSYS_ID(nlh->nlmsg_type),
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NFNL_MSG_TYPE(nlh->nlmsg_type));
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|
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/* Only requests are handled by kernel now. */
|
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if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
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DEBUGP("received non-request message\n");
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return 0;
|
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}
|
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|
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/* All the messages must at least contain nfgenmsg */
|
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if (nlh->nlmsg_len <
|
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NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg)))) {
|
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DEBUGP("received message was too short\n");
|
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return 0;
|
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}
|
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|
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type = nlh->nlmsg_type;
|
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ss = nfnetlink_get_subsys(type);
|
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if (!ss)
|
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goto err_inval;
|
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|
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nc = nfnetlink_find_client(type, ss);
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if (!nc) {
|
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DEBUGP("unable to find client for type %d\n", type);
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goto err_inval;
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}
|
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|
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if (nc->cap_required &&
|
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!cap_raised(NETLINK_CB(skb).eff_cap, nc->cap_required)) {
|
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DEBUGP("permission denied for type %d\n", type);
|
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*errp = -EPERM;
|
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return -1;
|
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}
|
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|
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{
|
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struct nfattr *cda[ss->attr_count];
|
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|
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memset(cda, 0, ss->attr_count*sizeof(struct nfattr *));
|
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|
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err = nfnetlink_check_attributes(ss, nlh, cda);
|
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if (err < 0)
|
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goto err_inval;
|
||||
|
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err = nc->call(nfnl, skb, nlh, cda, errp);
|
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*errp = err;
|
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return err;
|
||||
}
|
||||
|
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err_inval:
|
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*errp = -EINVAL;
|
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return -1;
|
||||
}
|
||||
|
||||
/* Process one packet of messages. */
|
||||
static inline int nfnetlink_rcv_skb(struct sk_buff *skb)
|
||||
{
|
||||
int err;
|
||||
struct nlmsghdr *nlh;
|
||||
|
||||
while (skb->len >= NLMSG_SPACE(0)) {
|
||||
u32 rlen;
|
||||
|
||||
nlh = (struct nlmsghdr *)skb->data;
|
||||
if (nlh->nlmsg_len < sizeof(struct nlmsghdr)
|
||||
|| skb->len < nlh->nlmsg_len)
|
||||
return 0;
|
||||
rlen = NLMSG_ALIGN(nlh->nlmsg_len);
|
||||
if (rlen > skb->len)
|
||||
rlen = skb->len;
|
||||
if (nfnetlink_rcv_msg(skb, nlh, &err)) {
|
||||
if (!err)
|
||||
return -1;
|
||||
netlink_ack(skb, nlh, err);
|
||||
} else
|
||||
if (nlh->nlmsg_flags & NLM_F_ACK)
|
||||
netlink_ack(skb, nlh, 0);
|
||||
skb_pull(skb, rlen);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void nfnetlink_rcv(struct sock *sk, int len)
|
||||
{
|
||||
do {
|
||||
struct sk_buff *skb;
|
||||
|
||||
if (nfnl_shlock_nowait())
|
||||
return;
|
||||
|
||||
while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
|
||||
if (nfnetlink_rcv_skb(skb)) {
|
||||
if (skb->len)
|
||||
skb_queue_head(&sk->sk_receive_queue,
|
||||
skb);
|
||||
else
|
||||
kfree_skb(skb);
|
||||
break;
|
||||
}
|
||||
kfree_skb(skb);
|
||||
}
|
||||
|
||||
up(&nfnl_sem);
|
||||
} while(nfnl && nfnl->sk_receive_queue.qlen);
|
||||
}
|
||||
|
||||
void __exit nfnetlink_exit(void)
|
||||
{
|
||||
printk("Removing netfilter NETLINK layer.\n");
|
||||
sock_release(nfnl->sk_socket);
|
||||
return;
|
||||
}
|
||||
|
||||
int __init nfnetlink_init(void)
|
||||
{
|
||||
printk("Netfilter messages via NETLINK v%s.\n", nfversion);
|
||||
|
||||
nfnl = netlink_kernel_create(NETLINK_NETFILTER, nfnetlink_rcv);
|
||||
if (!nfnl) {
|
||||
printk(KERN_ERR "cannot initialize nfnetlink!\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
module_init(nfnetlink_init);
|
||||
module_exit(nfnetlink_exit);
|
||||
|
||||
EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
|
||||
EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
|
||||
EXPORT_SYMBOL_GPL(nfnetlink_send);
|
||||
EXPORT_SYMBOL_GPL(nfnetlink_unicast);
|
||||
EXPORT_SYMBOL_GPL(nfattr_parse);
|
||||
EXPORT_SYMBOL_GPL(__nfa_fill);
|
||||
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