diff options
Diffstat (limited to 'net/core/netfilter.c')
| -rw-r--r-- | net/core/netfilter.c | 648 |
1 files changed, 0 insertions, 648 deletions
diff --git a/net/core/netfilter.c b/net/core/netfilter.c deleted file mode 100644 index 076c156d5eda9..0000000000000 --- a/net/core/netfilter.c +++ /dev/null @@ -1,648 +0,0 @@ -/* netfilter.c: look after the filters for various protocols. - * Heavily influenced by the old firewall.c by David Bonn and Alan Cox. - * - * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any - * way. - * - * Rusty Russell (C)2000 -- This code is GPL. - * - * February 2000: Modified by James Morris to have 1 queue per protocol. - * 15-Mar-2000: Added NF_REPEAT --RR. - * 08-May-2003: Internal logging interface added by Jozsef Kadlecsik. - */ -#include <linux/config.h> -#include <linux/kernel.h> -#include <linux/netfilter.h> -#include <net/protocol.h> -#include <linux/init.h> -#include <linux/skbuff.h> -#include <linux/wait.h> -#include <linux/module.h> -#include <linux/interrupt.h> -#include <linux/if.h> -#include <linux/netdevice.h> -#include <linux/inetdevice.h> -#include <linux/tcp.h> -#include <linux/udp.h> -#include <linux/icmp.h> -#include <net/sock.h> -#include <net/route.h> -#include <linux/ip.h> - -/* In this code, we can be waiting indefinitely for userspace to - * service a packet if a hook returns NF_QUEUE. We could keep a count - * of skbuffs queued for userspace, and not deregister a hook unless - * this is zero, but that sucks. Now, we simply check when the - * packets come back: if the hook is gone, the packet is discarded. */ -#ifdef CONFIG_NETFILTER_DEBUG -#define NFDEBUG(format, args...) printk(format , ## args) -#else -#define NFDEBUG(format, args...) -#endif - -/* Sockopts only registered and called from user context, so - net locking would be overkill. Also, [gs]etsockopt calls may - sleep. */ -static DECLARE_MUTEX(nf_sockopt_mutex); - -struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; -static LIST_HEAD(nf_sockopts); -static DEFINE_SPINLOCK(nf_hook_lock); - -/* - * A queue handler may be registered for each protocol. Each is protected by - * long term mutex. The handler must provide an an outfn() to accept packets - * for queueing and must reinject all packets it receives, no matter what. - */ -static struct nf_queue_handler_t { - nf_queue_outfn_t outfn; - void *data; -} queue_handler[NPROTO]; -static DEFINE_RWLOCK(queue_handler_lock); - -int nf_register_hook(struct nf_hook_ops *reg) -{ - struct list_head *i; - - spin_lock_bh(&nf_hook_lock); - list_for_each(i, &nf_hooks[reg->pf][reg->hooknum]) { - if (reg->priority < ((struct nf_hook_ops *)i)->priority) - break; - } - list_add_rcu(®->list, i->prev); - spin_unlock_bh(&nf_hook_lock); - - synchronize_net(); - return 0; -} - -void nf_unregister_hook(struct nf_hook_ops *reg) -{ - spin_lock_bh(&nf_hook_lock); - list_del_rcu(®->list); - spin_unlock_bh(&nf_hook_lock); - - synchronize_net(); -} - -/* Do exclusive ranges overlap? */ -static inline int overlap(int min1, int max1, int min2, int max2) -{ - return max1 > min2 && min1 < max2; -} - -/* Functions to register sockopt ranges (exclusive). */ -int nf_register_sockopt(struct nf_sockopt_ops *reg) -{ - struct list_head *i; - int ret = 0; - - if (down_interruptible(&nf_sockopt_mutex) != 0) - return -EINTR; - - list_for_each(i, &nf_sockopts) { - struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i; - if (ops->pf == reg->pf - && (overlap(ops->set_optmin, ops->set_optmax, - reg->set_optmin, reg->set_optmax) - || overlap(ops->get_optmin, ops->get_optmax, - reg->get_optmin, reg->get_optmax))) { - NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n", - ops->set_optmin, ops->set_optmax, - ops->get_optmin, ops->get_optmax, - reg->set_optmin, reg->set_optmax, - reg->get_optmin, reg->get_optmax); - ret = -EBUSY; - goto out; - } - } - - list_add(®->list, &nf_sockopts); -out: - up(&nf_sockopt_mutex); - return ret; -} - -void nf_unregister_sockopt(struct nf_sockopt_ops *reg) -{ - /* No point being interruptible: we're probably in cleanup_module() */ - restart: - down(&nf_sockopt_mutex); - if (reg->use != 0) { - /* To be woken by nf_sockopt call... */ - /* FIXME: Stuart Young's name appears gratuitously. */ - set_current_state(TASK_UNINTERRUPTIBLE); - reg->cleanup_task = current; - up(&nf_sockopt_mutex); - schedule(); - goto restart; - } - list_del(®->list); - up(&nf_sockopt_mutex); -} - -/* Call get/setsockopt() */ -static int nf_sockopt(struct sock *sk, int pf, int val, - char __user *opt, int *len, int get) -{ - struct list_head *i; - struct nf_sockopt_ops *ops; - int ret; - - if (down_interruptible(&nf_sockopt_mutex) != 0) - return -EINTR; - - list_for_each(i, &nf_sockopts) { - ops = (struct nf_sockopt_ops *)i; - if (ops->pf == pf) { - if (get) { - if (val >= ops->get_optmin - && val < ops->get_optmax) { - ops->use++; - up(&nf_sockopt_mutex); - ret = ops->get(sk, val, opt, len); - goto out; - } - } else { - if (val >= ops->set_optmin - && val < ops->set_optmax) { - ops->use++; - up(&nf_sockopt_mutex); - ret = ops->set(sk, val, opt, *len); - goto out; - } - } - } - } - up(&nf_sockopt_mutex); - return -ENOPROTOOPT; - - out: - down(&nf_sockopt_mutex); - ops->use--; - if (ops->cleanup_task) - wake_up_process(ops->cleanup_task); - up(&nf_sockopt_mutex); - return ret; -} - -int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt, - int len) -{ - return nf_sockopt(sk, pf, val, opt, &len, 0); -} - -int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len) -{ - return nf_sockopt(sk, pf, val, opt, len, 1); -} - -static unsigned int nf_iterate(struct list_head *head, - struct sk_buff **skb, - int hook, - const struct net_device *indev, - const struct net_device *outdev, - struct list_head **i, - int (*okfn)(struct sk_buff *), - int hook_thresh) -{ - unsigned int verdict; - - /* - * The caller must not block between calls to this - * function because of risk of continuing from deleted element. - */ - list_for_each_continue_rcu(*i, head) { - struct nf_hook_ops *elem = (struct nf_hook_ops *)*i; - - if (hook_thresh > elem->priority) - continue; - - /* Optimization: we don't need to hold module - reference here, since function can't sleep. --RR */ - verdict = elem->hook(hook, skb, indev, outdev, okfn); - if (verdict != NF_ACCEPT) { -#ifdef CONFIG_NETFILTER_DEBUG - if (unlikely(verdict > NF_MAX_VERDICT)) { - NFDEBUG("Evil return from %p(%u).\n", - elem->hook, hook); - continue; - } -#endif - if (verdict != NF_REPEAT) - return verdict; - *i = (*i)->prev; - } - } - return NF_ACCEPT; -} - -int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data) -{ - int ret; - - write_lock_bh(&queue_handler_lock); - if (queue_handler[pf].outfn) - ret = -EBUSY; - else { - queue_handler[pf].outfn = outfn; - queue_handler[pf].data = data; - ret = 0; - } - write_unlock_bh(&queue_handler_lock); - - return ret; -} - -/* The caller must flush their queue before this */ -int nf_unregister_queue_handler(int pf) -{ - write_lock_bh(&queue_handler_lock); - queue_handler[pf].outfn = NULL; - queue_handler[pf].data = NULL; - write_unlock_bh(&queue_handler_lock); - - return 0; -} - -/* - * Any packet that leaves via this function must come back - * through nf_reinject(). - */ -static int nf_queue(struct sk_buff *skb, - struct list_head *elem, - int pf, unsigned int hook, - struct net_device *indev, - struct net_device *outdev, - int (*okfn)(struct sk_buff *)) -{ - int status; - struct nf_info *info; -#ifdef CONFIG_BRIDGE_NETFILTER - struct net_device *physindev = NULL; - struct net_device *physoutdev = NULL; -#endif - - /* QUEUE == DROP if noone is waiting, to be safe. */ - read_lock(&queue_handler_lock); - if (!queue_handler[pf].outfn) { - read_unlock(&queue_handler_lock); - kfree_skb(skb); - return 1; - } - - info = kmalloc(sizeof(*info), GFP_ATOMIC); - if (!info) { - if (net_ratelimit()) - printk(KERN_ERR "OOM queueing packet %p\n", - skb); - read_unlock(&queue_handler_lock); - kfree_skb(skb); - return 1; - } - - *info = (struct nf_info) { - (struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn }; - - /* If it's going away, ignore hook. */ - if (!try_module_get(info->elem->owner)) { - read_unlock(&queue_handler_lock); - kfree(info); - return 0; - } - - /* Bump dev refs so they don't vanish while packet is out */ - if (indev) dev_hold(indev); - if (outdev) dev_hold(outdev); - -#ifdef CONFIG_BRIDGE_NETFILTER - if (skb->nf_bridge) { - physindev = skb->nf_bridge->physindev; - if (physindev) dev_hold(physindev); - physoutdev = skb->nf_bridge->physoutdev; - if (physoutdev) dev_hold(physoutdev); - } -#endif - - status = queue_handler[pf].outfn(skb, info, queue_handler[pf].data); - read_unlock(&queue_handler_lock); - - if (status < 0) { - /* James M doesn't say fuck enough. */ - if (indev) dev_put(indev); - if (outdev) dev_put(outdev); -#ifdef CONFIG_BRIDGE_NETFILTER - if (physindev) dev_put(physindev); - if (physoutdev) dev_put(physoutdev); -#endif - module_put(info->elem->owner); - kfree(info); - kfree_skb(skb); - return 1; - } - return 1; -} - -/* Returns 1 if okfn() needs to be executed by the caller, - * -EPERM for NF_DROP, 0 otherwise. */ -int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, - struct net_device *indev, - struct net_device *outdev, - int (*okfn)(struct sk_buff *), - int hook_thresh) -{ - struct list_head *elem; - unsigned int verdict; - int ret = 0; - - /* We may already have this, but read-locks nest anyway */ - rcu_read_lock(); - - elem = &nf_hooks[pf][hook]; -next_hook: - verdict = nf_iterate(&nf_hooks[pf][hook], pskb, hook, indev, - outdev, &elem, okfn, hook_thresh); - if (verdict == NF_ACCEPT || verdict == NF_STOP) { - ret = 1; - goto unlock; - } else if (verdict == NF_DROP) { - kfree_skb(*pskb); - ret = -EPERM; - } else if (verdict == NF_QUEUE) { - NFDEBUG("nf_hook: Verdict = QUEUE.\n"); - if (!nf_queue(*pskb, elem, pf, hook, indev, outdev, okfn)) - goto next_hook; - } -unlock: - rcu_read_unlock(); - return ret; -} - -void nf_reinject(struct sk_buff *skb, struct nf_info *info, - unsigned int verdict) -{ - struct list_head *elem = &info->elem->list; - struct list_head *i; - - rcu_read_lock(); - - /* Release those devices we held, or Alexey will kill me. */ - if (info->indev) dev_put(info->indev); - if (info->outdev) dev_put(info->outdev); -#ifdef CONFIG_BRIDGE_NETFILTER - if (skb->nf_bridge) { - if (skb->nf_bridge->physindev) - dev_put(skb->nf_bridge->physindev); - if (skb->nf_bridge->physoutdev) - dev_put(skb->nf_bridge->physoutdev); - } -#endif - - /* Drop reference to owner of hook which queued us. */ - module_put(info->elem->owner); - - list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) { - if (i == elem) - break; - } - - if (elem == &nf_hooks[info->pf][info->hook]) { - /* The module which sent it to userspace is gone. */ - NFDEBUG("%s: module disappeared, dropping packet.\n", - __FUNCTION__); - verdict = NF_DROP; - } - - /* Continue traversal iff userspace said ok... */ - if (verdict == NF_REPEAT) { - elem = elem->prev; - verdict = NF_ACCEPT; - } - - if (verdict == NF_ACCEPT) { - next_hook: - verdict = nf_iterate(&nf_hooks[info->pf][info->hook], - &skb, info->hook, - info->indev, info->outdev, &elem, - info->okfn, INT_MIN); - } - - switch (verdict) { - case NF_ACCEPT: - info->okfn(skb); - break; - - case NF_QUEUE: - if (!nf_queue(skb, elem, info->pf, info->hook, - info->indev, info->outdev, info->okfn)) - goto next_hook; - break; - } - rcu_read_unlock(); - - if (verdict == NF_DROP) - kfree_skb(skb); - - kfree(info); - return; -} - -#ifdef CONFIG_INET -/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ -int ip_route_me_harder(struct sk_buff **pskb) -{ - struct iphdr *iph = (*pskb)->nh.iph; - struct rtable *rt; - struct flowi fl = {}; - struct dst_entry *odst; - unsigned int hh_len; - - /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause - * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook. - */ - if (inet_addr_type(iph->saddr) == RTN_LOCAL) { - fl.nl_u.ip4_u.daddr = iph->daddr; - fl.nl_u.ip4_u.saddr = iph->saddr; - fl.nl_u.ip4_u.tos = RT_TOS(iph->tos); - fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0; -#ifdef CONFIG_IP_ROUTE_FWMARK - fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark; -#endif - fl.proto = iph->protocol; - if (ip_route_output_key(&rt, &fl) != 0) - return -1; - - /* Drop old route. */ - dst_release((*pskb)->dst); - (*pskb)->dst = &rt->u.dst; - } else { - /* non-local src, find valid iif to satisfy - * rp-filter when calling ip_route_input. */ - fl.nl_u.ip4_u.daddr = iph->saddr; - if (ip_route_output_key(&rt, &fl) != 0) - return -1; - - odst = (*pskb)->dst; - if (ip_route_input(*pskb, iph->daddr, iph->saddr, - RT_TOS(iph->tos), rt->u.dst.dev) != 0) { - dst_release(&rt->u.dst); - return -1; - } - dst_release(&rt->u.dst); - dst_release(odst); - } - - if ((*pskb)->dst->error) - return -1; - - /* Change in oif may mean change in hh_len. */ - hh_len = (*pskb)->dst->dev->hard_header_len; - if (skb_headroom(*pskb) < hh_len) { - struct sk_buff *nskb; - - nskb = skb_realloc_headroom(*pskb, hh_len); - if (!nskb) - return -1; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } - - return 0; -} -EXPORT_SYMBOL(ip_route_me_harder); - -int skb_ip_make_writable(struct sk_buff **pskb, unsigned int writable_len) -{ - struct sk_buff *nskb; - - if (writable_len > (*pskb)->len) - return 0; - - /* Not exclusive use of packet? Must copy. */ - if (skb_shared(*pskb) || skb_cloned(*pskb)) - goto copy_skb; - - return pskb_may_pull(*pskb, writable_len); - -copy_skb: - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return 0; - BUG_ON(skb_is_nonlinear(nskb)); - - /* Rest of kernel will get very unhappy if we pass it a - suddenly-orphaned skbuff */ - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - return 1; -} -EXPORT_SYMBOL(skb_ip_make_writable); -#endif /*CONFIG_INET*/ - -/* Internal logging interface, which relies on the real - LOG target modules */ - -#define NF_LOG_PREFIXLEN 128 - -static nf_logfn *nf_logging[NPROTO]; /* = NULL */ -static int reported = 0; -static DEFINE_SPINLOCK(nf_log_lock); - -int nf_log_register(int pf, nf_logfn *logfn) -{ - int ret = -EBUSY; - - /* Any setup of logging members must be done before - * substituting pointer. */ - spin_lock(&nf_log_lock); - if (!nf_logging[pf]) { - rcu_assign_pointer(nf_logging[pf], logfn); - ret = 0; - } - spin_unlock(&nf_log_lock); - return ret; -} - -void nf_log_unregister(int pf, nf_logfn *logfn) -{ - spin_lock(&nf_log_lock); - if (nf_logging[pf] == logfn) - nf_logging[pf] = NULL; - spin_unlock(&nf_log_lock); - - /* Give time to concurrent readers. */ - synchronize_net(); -} - -void nf_log_packet(int pf, - unsigned int hooknum, - const struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - const char *fmt, ...) -{ - va_list args; - char prefix[NF_LOG_PREFIXLEN]; - nf_logfn *logfn; - - rcu_read_lock(); - logfn = rcu_dereference(nf_logging[pf]); - if (logfn) { - va_start(args, fmt); - vsnprintf(prefix, sizeof(prefix), fmt, args); - va_end(args); - /* We must read logging before nf_logfn[pf] */ - logfn(hooknum, skb, in, out, prefix); - } else if (!reported) { - printk(KERN_WARNING "nf_log_packet: can\'t log yet, " - "no backend logging module loaded in!\n"); - reported++; - } - rcu_read_unlock(); -} -EXPORT_SYMBOL(nf_log_register); -EXPORT_SYMBOL(nf_log_unregister); -EXPORT_SYMBOL(nf_log_packet); - -/* This does not belong here, but locally generated errors need it if connection - tracking in use: without this, connection may not be in hash table, and hence - manufactured ICMP or RST packets will not be associated with it. */ -void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); - -void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) -{ - void (*attach)(struct sk_buff *, struct sk_buff *); - - if (skb->nfct && (attach = ip_ct_attach) != NULL) { - mb(); /* Just to be sure: must be read before executing this */ - attach(new, skb); - } -} - -void __init netfilter_init(void) -{ - int i, h; - - for (i = 0; i < NPROTO; i++) { - for (h = 0; h < NF_MAX_HOOKS; h++) - INIT_LIST_HEAD(&nf_hooks[i][h]); - } -} - -EXPORT_SYMBOL(ip_ct_attach); -EXPORT_SYMBOL(nf_ct_attach); -EXPORT_SYMBOL(nf_getsockopt); -EXPORT_SYMBOL(nf_hook_slow); -EXPORT_SYMBOL(nf_hooks); -EXPORT_SYMBOL(nf_register_hook); -EXPORT_SYMBOL(nf_register_queue_handler); -EXPORT_SYMBOL(nf_register_sockopt); -EXPORT_SYMBOL(nf_reinject); -EXPORT_SYMBOL(nf_setsockopt); -EXPORT_SYMBOL(nf_unregister_hook); -EXPORT_SYMBOL(nf_unregister_queue_handler); -EXPORT_SYMBOL(nf_unregister_sockopt); |