From d86fb4e9d55311c68244ae1fb40f6e3f3a454e19 Mon Sep 17 00:00:00 2001 From: Bart De Schuymer Date: Sat, 24 Aug 2002 09:23:41 +0000 Subject: *** empty log message *** --- br-nf-bds/linux2.5/net/core/netfilter.c | 654 ++++++++++++++++++++++++++++++++ 1 file changed, 654 insertions(+) create mode 100644 br-nf-bds/linux2.5/net/core/netfilter.c (limited to 'br-nf-bds/linux2.5/net/core/netfilter.c') diff --git a/br-nf-bds/linux2.5/net/core/netfilter.c b/br-nf-bds/linux2.5/net/core/netfilter.c new file mode 100644 index 0000000..198dad6 --- /dev/null +++ b/br-nf-bds/linux2.5/net/core/netfilter.c @@ -0,0 +1,654 @@ +/* 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. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define __KERNEL_SYSCALLS__ +#include + +/* 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 + BR_NETPROTO_LOCK 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); + +/* + * 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]; + +int nf_register_hook(struct nf_hook_ops *reg) +{ + struct list_head *i; + + br_write_lock_bh(BR_NETPROTO_LOCK); + for (i = nf_hooks[reg->pf][reg->hooknum].next; + i != &nf_hooks[reg->pf][reg->hooknum]; + i = i->next) { + if (reg->priority < ((struct nf_hook_ops *)i)->priority) + break; + } + list_add(®->list, i->prev); + br_write_unlock_bh(BR_NETPROTO_LOCK); + return 0; +} + +void nf_unregister_hook(struct nf_hook_ops *reg) +{ + br_write_lock_bh(BR_NETPROTO_LOCK); + list_del(®->list); + br_write_unlock_bh(BR_NETPROTO_LOCK); +} + +/* 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; + + for (i = nf_sockopts.next; i != &nf_sockopts; i = i->next) { + 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); +} + +#ifdef CONFIG_NETFILTER_DEBUG +#include +#include +#include +#include + +static void debug_print_hooks_ip(unsigned int nf_debug) +{ + if (nf_debug & (1 << NF_IP_PRE_ROUTING)) { + printk("PRE_ROUTING "); + nf_debug ^= (1 << NF_IP_PRE_ROUTING); + } + if (nf_debug & (1 << NF_IP_LOCAL_IN)) { + printk("LOCAL_IN "); + nf_debug ^= (1 << NF_IP_LOCAL_IN); + } + if (nf_debug & (1 << NF_IP_FORWARD)) { + printk("FORWARD "); + nf_debug ^= (1 << NF_IP_FORWARD); + } + if (nf_debug & (1 << NF_IP_LOCAL_OUT)) { + printk("LOCAL_OUT "); + nf_debug ^= (1 << NF_IP_LOCAL_OUT); + } + if (nf_debug & (1 << NF_IP_POST_ROUTING)) { + printk("POST_ROUTING "); + nf_debug ^= (1 << NF_IP_POST_ROUTING); + } + if (nf_debug) + printk("Crap bits: 0x%04X", nf_debug); + printk("\n"); +} + +void nf_dump_skb(int pf, struct sk_buff *skb) +{ + printk("skb: pf=%i %s dev=%s len=%u\n", + pf, + skb->sk ? "(owned)" : "(unowned)", + skb->dev ? skb->dev->name : "(no dev)", + skb->len); + switch (pf) { + case PF_INET: { + const struct iphdr *ip = skb->nh.iph; + __u32 *opt = (__u32 *) (ip + 1); + int opti; + __u16 src_port = 0, dst_port = 0; + + if (ip->protocol == IPPROTO_TCP + || ip->protocol == IPPROTO_UDP) { + struct tcphdr *tcp=(struct tcphdr *)((__u32 *)ip+ip->ihl); + src_port = ntohs(tcp->source); + dst_port = ntohs(tcp->dest); + } + + printk("PROTO=%d %u.%u.%u.%u:%hu %u.%u.%u.%u:%hu" + " L=%hu S=0x%2.2hX I=%hu F=0x%4.4hX T=%hu", + ip->protocol, NIPQUAD(ip->saddr), + src_port, NIPQUAD(ip->daddr), + dst_port, + ntohs(ip->tot_len), ip->tos, ntohs(ip->id), + ntohs(ip->frag_off), ip->ttl); + + for (opti = 0; opti < (ip->ihl - sizeof(struct iphdr) / 4); opti++) + printk(" O=0x%8.8X", *opt++); + printk("\n"); + } + } +} + +void nf_debug_ip_local_deliver(struct sk_buff *skb) +{ + /* If it's a loopback packet, it must have come through + * NF_IP_LOCAL_OUT, NF_IP_RAW_INPUT, NF_IP_PRE_ROUTING and + * NF_IP_LOCAL_IN. Otherwise, must have gone through + * NF_IP_RAW_INPUT and NF_IP_PRE_ROUTING. */ + if (!skb->dev) { + printk("ip_local_deliver: skb->dev is NULL.\n"); + } + else if (strcmp(skb->dev->name, "lo") == 0) { + if (skb->nf_debug != ((1 << NF_IP_LOCAL_OUT) + | (1 << NF_IP_POST_ROUTING) + | (1 << NF_IP_PRE_ROUTING) + | (1 << NF_IP_LOCAL_IN))) { + printk("ip_local_deliver: bad loopback skb: "); + debug_print_hooks_ip(skb->nf_debug); + nf_dump_skb(PF_INET, skb); + } + } + else { + if (skb->nf_debug != ((1<nf_debug); + nf_dump_skb(PF_INET, skb); + } + } +} + +void nf_debug_ip_loopback_xmit(struct sk_buff *newskb) +{ + if (newskb->nf_debug != ((1 << NF_IP_LOCAL_OUT) + | (1 << NF_IP_POST_ROUTING))) { + printk("ip_dev_loopback_xmit: bad owned skb = %p: ", + newskb); + debug_print_hooks_ip(newskb->nf_debug); + nf_dump_skb(PF_INET, newskb); + } + /* Clear to avoid confusing input check */ + newskb->nf_debug = 0; +} + +void nf_debug_ip_finish_output2(struct sk_buff *skb) +{ + /* If it's owned, it must have gone through the + * NF_IP_LOCAL_OUT and NF_IP_POST_ROUTING. + * Otherwise, must have gone through + * NF_IP_PRE_ROUTING, NF_IP_FORWARD and NF_IP_POST_ROUTING. + */ + if (skb->sk) { + if (skb->nf_debug != ((1 << NF_IP_LOCAL_OUT) + | (1 << NF_IP_POST_ROUTING))) { + printk("ip_finish_output: bad owned skb = %p: ", skb); + debug_print_hooks_ip(skb->nf_debug); + nf_dump_skb(PF_INET, skb); + } + } else { + if (skb->nf_debug != ((1 << NF_IP_PRE_ROUTING) + | (1 << NF_IP_FORWARD) + | (1 << NF_IP_POST_ROUTING))) { + /* Fragments, entunnelled packets, TCP RSTs + generated by ipt_REJECT will have no + owners, but still may be local */ + if (skb->nf_debug != ((1 << NF_IP_LOCAL_OUT) + | (1 << NF_IP_POST_ROUTING))){ + printk("ip_finish_output:" + " bad unowned skb = %p: ",skb); + debug_print_hooks_ip(skb->nf_debug); + nf_dump_skb(PF_INET, skb); + } + } + } +} +#endif /*CONFIG_NETFILTER_DEBUG*/ + +/* Call get/setsockopt() */ +static int nf_sockopt(struct sock *sk, int pf, int val, + char *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; + + for (i = nf_sockopts.next; i != &nf_sockopts; i = i->next) { + 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 *opt, + int len) +{ + return nf_sockopt(sk, pf, val, opt, &len, 0); +} + +int nf_getsockopt(struct sock *sk, int pf, int val, char *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) +{ + for (*i = (*i)->next; *i != head; *i = (*i)->next) { + struct nf_hook_ops *elem = (struct nf_hook_ops *)*i; + + if (hook_thresh > elem->priority) + continue; + + switch (elem->hook(hook, skb, indev, outdev, okfn)) { + case NF_QUEUE: + return NF_QUEUE; + + case NF_STOLEN: + return NF_STOLEN; + + case NF_DROP: + return NF_DROP; + + case NF_REPEAT: + *i = (*i)->prev; + break; + +#ifdef CONFIG_NETFILTER_DEBUG + case NF_ACCEPT: + break; + + default: + NFDEBUG("Evil return from %p(%u).\n", + elem->hook, hook); +#endif + } + } + return NF_ACCEPT; +} + +int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data) +{ + int ret; + + br_write_lock_bh(BR_NETPROTO_LOCK); + if (queue_handler[pf].outfn) + ret = -EBUSY; + else { + queue_handler[pf].outfn = outfn; + queue_handler[pf].data = data; + ret = 0; + } + br_write_unlock_bh(BR_NETPROTO_LOCK); + + return ret; +} + +/* The caller must flush their queue before this */ +int nf_unregister_queue_handler(int pf) +{ + br_write_lock_bh(BR_NETPROTO_LOCK); + queue_handler[pf].outfn = NULL; + queue_handler[pf].data = NULL; + br_write_unlock_bh(BR_NETPROTO_LOCK); + return 0; +} + +/* + * Any packet that leaves via this function must come back + * through nf_reinject(). + */ +static void 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; + struct net_device *physindev; + struct net_device *physoutdev; + + if (!queue_handler[pf].outfn) { + kfree_skb(skb); + return; + } + + info = kmalloc(sizeof(*info), GFP_ATOMIC); + if (!info) { + if (net_ratelimit()) + printk(KERN_ERR "OOM queueing packet %p\n", + skb); + kfree_skb(skb); + return; + } + + *info = (struct nf_info) { + (struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn }; + + /* Bump dev refs so they don't vanish while packet is out */ + if (indev) dev_hold(indev); + if (outdev) dev_hold(outdev); + + if ((physindev = skb->physindev)) dev_hold(physindev); + if ((physoutdev = skb->physoutdev)) dev_hold(physoutdev); + + status = queue_handler[pf].outfn(skb, info, queue_handler[pf].data); + if (status < 0) { + /* James M doesn't say fuck enough. */ + if (indev) dev_put(indev); + if (outdev) dev_put(outdev); + if (physindev) dev_put(physindev); + if (physoutdev) dev_put(physoutdev); + kfree(info); + kfree_skb(skb); + return; + } +} + +int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, + 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; + + /* This stopgap cannot be removed until all the hooks are audited. */ + if (skb_is_nonlinear(skb) && skb_linearize(skb, GFP_ATOMIC) != 0) { + kfree_skb(skb); + return -ENOMEM; + } + if (skb->ip_summed == CHECKSUM_HW) { + if (outdev == NULL) { + skb->ip_summed = CHECKSUM_NONE; + } else { + skb_checksum_help(skb); + } + } + + /* We may already have this, but read-locks nest anyway */ + br_read_lock_bh(BR_NETPROTO_LOCK); + +#ifdef CONFIG_NETFILTER_DEBUG + if (skb->nf_debug & (1 << hook)) { + printk("nf_hook: hook %i already set.\n", hook); + nf_dump_skb(pf, skb); + } + skb->nf_debug |= (1 << hook); +#endif + + elem = &nf_hooks[pf][hook]; + verdict = nf_iterate(&nf_hooks[pf][hook], &skb, hook, indev, + outdev, &elem, okfn, hook_thresh); + if (verdict == NF_QUEUE) { + NFDEBUG("nf_hook: Verdict = QUEUE.\n"); + nf_queue(skb, elem, pf, hook, indev, outdev, okfn); + } + + switch (verdict) { + case NF_ACCEPT: + ret = okfn(skb); + break; + + case NF_DROP: + kfree_skb(skb); + ret = -EPERM; + break; + } + + br_read_unlock_bh(BR_NETPROTO_LOCK); + 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; + + /* We don't have BR_NETPROTO_LOCK here */ + br_read_lock_bh(BR_NETPROTO_LOCK); + for (i = nf_hooks[info->pf][info->hook].next; i != elem; i = i->next) { + if (i == &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; + break; + } + } + + /* Continue traversal iff userspace said ok... */ + if (verdict == NF_REPEAT) { + elem = elem->prev; + verdict = NF_ACCEPT; + } + + if (verdict == NF_ACCEPT) { + 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: + nf_queue(skb, elem, info->pf, info->hook, + info->indev, info->outdev, info->okfn); + break; + + case NF_DROP: + kfree_skb(skb); + break; + } + br_read_unlock_bh(BR_NETPROTO_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); + + 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 rt_key key = { dst:iph->daddr, + src:iph->saddr, + oif:(*pskb)->sk ? (*pskb)->sk->bound_dev_if : 0, + tos:RT_TOS(iph->tos)|RTO_CONN, +#ifdef CONFIG_IP_ROUTE_FWMARK + fwmark:(*pskb)->nfmark +#endif + }; + struct net_device *dev_src = NULL; + int err; + + /* accomodate ip_route_output_slow(), which expects the key src to be + 0 or a local address; however some non-standard hacks like + ipt_REJECT.c:send_reset() can cause packets with foreign + saddr to be appear on the NF_IP_LOCAL_OUT hook -MB */ + if(key.src && !(dev_src = ip_dev_find(key.src))) + key.src = 0; + + if ((err=ip_route_output_key(&rt, &key)) != 0) { + printk("route_me_harder: ip_route_output_key(dst=%u.%u.%u.%u, src=%u.%u.%u.%u, oif=%d, tos=0x%x, fwmark=0x%lx) error %d\n", + NIPQUAD(iph->daddr), NIPQUAD(iph->saddr), + (*pskb)->sk ? (*pskb)->sk->bound_dev_if : 0, + RT_TOS(iph->tos)|RTO_CONN, +#ifdef CONFIG_IP_ROUTE_FWMARK + (*pskb)->nfmark, +#else + 0UL, +#endif + err); + goto out; + } + + /* Drop old route. */ + dst_release((*pskb)->dst); + + (*pskb)->dst = &rt->u.dst; + + /* Change in oif may mean change in hh_len. */ + if (skb_headroom(*pskb) < (*pskb)->dst->dev->hard_header_len) { + struct sk_buff *nskb; + + nskb = skb_realloc_headroom(*pskb, + (*pskb)->dst->dev->hard_header_len); + if (!nskb) { + err = -ENOMEM; + goto out; + } + if ((*pskb)->sk) + skb_set_owner_w(nskb, (*pskb)->sk); + kfree_skb(*pskb); + *pskb = nskb; + } + +out: + if (dev_src) + dev_put(dev_src); + + return err; +} +#endif /*CONFIG_INET*/ + +/* This does not belong here, but ipt_REJECT needs 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 nf_ct_info *); + +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]); + } +} -- cgit v1.2.3