diff options
| -rw-r--r-- | include/linux/netfilter/nfnetlink.h | 145 | ||||
| -rw-r--r-- | net/Kconfig | 2 | ||||
| -rw-r--r-- | net/Makefile | 1 | ||||
| -rw-r--r-- | net/netfilter/Kconfig | 5 | ||||
| -rw-r--r-- | net/netfilter/Makefile | 1 | ||||
| -rw-r--r-- | net/netfilter/nfnetlink.c | 343 |
6 files changed, 497 insertions, 0 deletions
diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h new file mode 100644 index 0000000..8f1bfb8 --- /dev/null +++ b/include/linux/netfilter/nfnetlink.h @@ -0,0 +1,145 @@ +#ifndef _NFNETLINK_H +#define _NFNETLINK_H +#include <linux/types.h> + +/* nfnetlink groups: Up to 32 maximum */ +#define NF_NETLINK_CONNTRACK_NEW 0x00000001 +#define NF_NETLINK_CONNTRACK_UPDATE 0x00000002 +#define NF_NETLINK_CONNTRACK_DESTROY 0x00000004 +#define NF_NETLINK_CONNTRACK_EXP_NEW 0x00000008 +#define NF_NETLINK_CONNTRACK_EXP_UPDATE 0x00000010 +#define NF_NETLINK_CONNTRACK_EXP_DESTROY 0x00000020 + +/* Generic structure for encapsulation optional netfilter information. + * It is reminiscent of sockaddr, but with sa_family replaced + * with attribute type. + * ! This should someday be put somewhere generic as now rtnetlink and + * ! nfnetlink use the same attributes methods. - J. Schulist. + */ + +struct nfattr +{ + u_int16_t nfa_len; + u_int16_t nfa_type; +} __attribute__ ((packed)); + +/* FIXME: Shamelessly copy and pasted from rtnetlink.h, it's time + * to put this in a generic file */ + +#define NFA_ALIGNTO 4 +#define NFA_ALIGN(len) (((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1)) +#define NFA_OK(nfa,len) ((len) > 0 && (nfa)->nfa_len >= sizeof(struct nfattr) \ + && (nfa)->nfa_len <= (len)) +#define NFA_NEXT(nfa,attrlen) ((attrlen) -= NFA_ALIGN((nfa)->nfa_len), \ + (struct nfattr *)(((char *)(nfa)) + NFA_ALIGN((nfa)->nfa_len))) +#define NFA_LENGTH(len) (NFA_ALIGN(sizeof(struct nfattr)) + (len)) +#define NFA_SPACE(len) NFA_ALIGN(NFA_LENGTH(len)) +#define NFA_DATA(nfa) ((void *)(((char *)(nfa)) + NFA_LENGTH(0))) +#define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0)) +#define NFA_NEST(skb, type) \ +({ struct nfattr *__start = (struct nfattr *) (skb)->tail; \ + NFA_PUT(skb, type, 0, NULL); \ + __start; }) +#define NFA_NEST_END(skb, start) \ +({ (start)->nfa_len = ((skb)->tail - (unsigned char *) (start)); \ + (skb)->len; }) +#define NFA_NEST_CANCEL(skb, start) \ +({ if (start) \ + skb_trim(skb, (unsigned char *) (start) - (skb)->data); \ + -1; }) + +/* General form of address family dependent message. + */ +struct nfgenmsg { + u_int8_t nfgen_family; /* AF_xxx */ + u_int8_t version; /* nfnetlink version */ + u_int16_t res_id; /* resource id */ +} __attribute__ ((packed)); + +#define NFNETLINK_V1 1 + +#define NFM_NFA(n) ((struct nfattr *)(((char *)(n)) \ + + NLMSG_ALIGN(sizeof(struct nfgenmsg)))) +#define NFM_PAYLOAD(n) NLMSG_PAYLOAD(n, sizeof(struct nfgenmsg)) + +/* netfilter netlink message types are split in two pieces: + * 8 bit subsystem, 8bit operation. + */ + +#define NFNL_SUBSYS_ID(x) ((x & 0xff00) >> 8) +#define NFNL_MSG_TYPE(x) (x & 0x00ff) + +enum nfnl_subsys_id { + NFNL_SUBSYS_NONE = 0, + NFNL_SUBSYS_CTNETLINK, + NFNL_SUBSYS_CTNETLINK_EXP, + NFNL_SUBSYS_IPTNETLINK, + NFNL_SUBSYS_QUEUE, + NFNL_SUBSYS_ULOG, + NFNL_SUBSYS_COUNT, +}; + +#ifdef __KERNEL__ + +#include <linux/capability.h> + +struct nfnl_callback +{ + kernel_cap_t cap_required; /* capabilities required for this msg */ + int (*call)(struct sock *nl, struct sk_buff *skb, + struct nlmsghdr *nlh, struct nfattr *cda[], int *errp); +}; + +struct nfnetlink_subsystem +{ + const char *name; + __u8 subsys_id; /* nfnetlink subsystem ID */ + __u8 cb_count; /* number of callbacks */ + u_int32_t attr_count; /* number of nfattr's */ + struct nfnl_callback *cb; /* callback for individual types */ +}; + +extern void __nfa_fill(struct sk_buff *skb, int attrtype, + int attrlen, const void *data); +#define NFA_PUT(skb, attrtype, attrlen, data) \ +({ if (skb_tailroom(skb) < (int)NFA_SPACE(attrlen)) goto nfattr_failure; \ + __nfa_fill(skb, attrtype, attrlen, data); }) + +extern struct semaphore nfnl_sem; + +#define nfnl_shlock() down(&nfnl_sem) +#define nfnl_shlock_nowait() down_trylock(&nfnl_sem) + +#define nfnl_shunlock() do { up(&nfnl_sem); \ + if(nfnl && nfnl->sk_receive_queue.qlen) \ + nfnl->sk_data_ready(nfnl, 0); \ + } while(0) + +extern void nfnl_lock(void); +extern void nfnl_unlock(void); + +extern int nfnetlink_subsys_register(struct nfnetlink_subsystem *n); +extern int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n); + +extern int nfattr_parse(struct nfattr *tb[], int maxattr, + struct nfattr *nfa, int len); + +#define nfattr_parse_nested(tb, max, nfa) \ + nfattr_parse((tb), (max), NFA_DATA((nfa)), NFA_PAYLOAD((nfa))) + +#define nfattr_bad_size(tb, max, cta_min) \ +({ int __i, __res = 0; \ + for (__i=0; __i<max; __i++) \ + if (tb[__i] && NFA_PAYLOAD(tb[__i]) < cta_min[__i]){ \ + __res = 1; \ + break; \ + } \ + __res; \ +}) + +extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, + int echo); +extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags); + +#endif /* __KERNEL__ */ +#endif /* _NFNETLINK_H */ diff --git a/net/Kconfig b/net/Kconfig index 40a31ba8..02877ac 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -205,6 +205,8 @@ config NET_PKTGEN To compile this code as a module, choose M here: the module will be called pktgen. +source "net/netfilter/Kconfig" + endmenu endmenu diff --git a/net/Makefile b/net/Makefile index 8e2bdc0..4a01be8 100644 --- a/net/Makefile +++ b/net/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_NET) += $(tmp-y) obj-$(CONFIG_LLC) += llc/ obj-$(CONFIG_NET) += ethernet/ 802/ sched/ netlink/ obj-$(CONFIG_INET) += ipv4/ +obj-$(CONFIG_NETFILTER) += netfilter/ obj-$(CONFIG_XFRM) += xfrm/ obj-$(CONFIG_UNIX) += unix/ ifneq ($(CONFIG_IPV6),) diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig new file mode 100644 index 0000000..3629d3d --- /dev/null +++ b/net/netfilter/Kconfig @@ -0,0 +1,5 @@ +config NETFILTER_NETLINK + tristate "Netfilter netlink interface" + help + If this option is enabled, the kernel will include support + for the new netfilter netlink interface. diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile new file mode 100644 index 0000000..02e67d3 --- /dev/null +++ b/net/netfilter/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c new file mode 100644 index 0000000..710acd7 --- /dev/null +++ b/net/netfilter/nfnetlink.c @@ -0,0 +1,343 @@ +/* Netfilter messages via netlink socket. Allows for user space + * protocol helpers and general trouble making from userspace. + * + * (C) 2001 by Jay Schulist <jschlst@samba.org>, + * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org> + * (C) 2005 by Pablo Neira Ayuso <pablo@eurodev.net> + * + * Initial netfilter messages via netlink development funded and + * generally made possible by Network Robots, Inc. (www.networkrobots.com) + * + * Further development of this code funded by Astaro AG (http://www.astaro.com) + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/kernel.h> +#include <linux/major.h> +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/fcntl.h> +#include <linux/skbuff.h> +#include <asm/uaccess.h> +#include <asm/system.h> +#include <net/sock.h> +#include <linux/init.h> +#include <linux/spinlock.h> + +#include <linux/netfilter.h> +#include <linux/netlink.h> +#include <linux/netfilter/nfnetlink.h> + +MODULE_LICENSE("GPL"); + +static char __initdata nfversion[] = "0.30"; + +#if 0 +#define DEBUGP printk +#else +#define DEBUGP(format, args...) +#endif + +static struct sock *nfnl = NULL; +static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT]; +DECLARE_MUTEX(nfnl_sem); + +void nfnl_lock(void) +{ + nfnl_shlock(); +} + +void nfnl_unlock(void) +{ + nfnl_shunlock(); +} + +int nfnetlink_subsys_register(struct nfnetlink_subsystem *n) +{ + DEBUGP("registering subsystem ID %u\n", n->subsys_id); + + /* If the netlink socket wasn't created, then fail */ + if (!nfnl) + return -1; + + nfnl_lock(); + subsys_table[n->subsys_id] = n; + nfnl_unlock(); + + return 0; +} + +int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n) +{ + DEBUGP("unregistering subsystem ID %u\n", n->subsys_id); + + nfnl_lock(); + subsys_table[n->subsys_id] = NULL; + nfnl_unlock(); + + return 0; +} + +static inline struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) +{ + u_int8_t subsys_id = NFNL_SUBSYS_ID(type); + + if (subsys_id >= NFNL_SUBSYS_COUNT + || subsys_table[subsys_id] == NULL) + return NULL; + + return subsys_table[subsys_id]; +} + +static inline struct nfnl_callback * +nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss) +{ + u_int8_t cb_id = NFNL_MSG_TYPE(type); + + if (cb_id >= ss->cb_count) { + DEBUGP("msgtype %u >= %u, returning\n", type, ss->cb_count); + return NULL; + } + + return &ss->cb[cb_id]; +} + +void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen, + const void *data) +{ + struct nfattr *nfa; + int size = NFA_LENGTH(attrlen); + + nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size)); + nfa->nfa_type = attrtype; + nfa->nfa_len = size; + memcpy(NFA_DATA(nfa), data, attrlen); +} + +int nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len) +{ + memset(tb, 0, sizeof(struct nfattr *) * maxattr); + + while (NFA_OK(nfa, len)) { + unsigned flavor = nfa->nfa_type; + if (flavor && flavor <= maxattr) + tb[flavor-1] = nfa; + nfa = NFA_NEXT(nfa, len); + } + + return 0; +} + +/** + * nfnetlink_check_attributes - check and parse nfnetlink attributes + * + * subsys: nfnl subsystem for which this message is to be parsed + * nlmsghdr: netlink message to be checked/parsed + * cda: array of pointers, needs to be at least subsys->attr_count big + * + */ +static int +nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys, + struct nlmsghdr *nlh, struct nfattr *cda[]) +{ + int min_len; + + memset(cda, 0, sizeof(struct nfattr *) * subsys->attr_count); + + /* check attribute lengths. */ + min_len = NLMSG_ALIGN(sizeof(struct nfgenmsg)); + if (nlh->nlmsg_len < min_len) + return -EINVAL; + + if (nlh->nlmsg_len > min_len) { + struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh)); + int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len); + + while (NFA_OK(attr, attrlen)) { + unsigned flavor = attr->nfa_type; + if (flavor) { + if (flavor > subsys->attr_count) + return -EINVAL; + cda[flavor - 1] = attr; + } + attr = NFA_NEXT(attr, attrlen); + } + } else + return -EINVAL; + + return 0; +} + +int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo) +{ + int allocation = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL; + int err = 0; + + NETLINK_CB(skb).dst_groups = group; + if (echo) + atomic_inc(&skb->users); + netlink_broadcast(nfnl, skb, pid, group, allocation); + if (echo) + err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT); + + return err; +} + +int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags) +{ + return netlink_unicast(nfnl, skb, pid, flags); +} + +/* Process one complete nfnetlink message. */ +static inline int nfnetlink_rcv_msg(struct sk_buff *skb, + struct nlmsghdr *nlh, int *errp) +{ + struct nfnl_callback *nc; + struct nfnetlink_subsystem *ss; + int type, err = 0; + + DEBUGP("entered; subsys=%u, msgtype=%u\n", + NFNL_SUBSYS_ID(nlh->nlmsg_type), + NFNL_MSG_TYPE(nlh->nlmsg_type)); + + /* Only requests are handled by kernel now. */ + if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { + DEBUGP("received non-request message\n"); + return 0; + } + + /* All the messages must at least contain nfgenmsg */ + if (nlh->nlmsg_len < + NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg)))) { + DEBUGP("received message was too short\n"); + return 0; + } + + type = nlh->nlmsg_type; + ss = nfnetlink_get_subsys(type); + if (!ss) + goto err_inval; + + nc = nfnetlink_find_client(type, ss); + if (!nc) { + DEBUGP("unable to find client for type %d\n", type); + goto err_inval; + } + + if (nc->cap_required && + !cap_raised(NETLINK_CB(skb).eff_cap, nc->cap_required)) { + DEBUGP("permission denied for type %d\n", type); + *errp = -EPERM; + return -1; + } + + { + struct nfattr *cda[ss->attr_count]; + + memset(cda, 0, ss->attr_count*sizeof(struct nfattr *)); + + err = nfnetlink_check_attributes(ss, nlh, cda); + if (err < 0) + goto err_inval; + + err = nc->call(nfnl, skb, nlh, cda, errp); + *errp = err; + return err; + } + +err_inval: + *errp = -EINVAL; + 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); |
