diff options
Diffstat (limited to 'net')
| -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 |
5 files changed, 352 insertions, 0 deletions
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); |