2 * Packet matching code for ARP packets.
4 * Based heavily, if not almost entirely, upon ip_tables.c framework.
6 * Some ARP specific bits are:
8 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
9 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/kernel.h>
14 #include <linux/skbuff.h>
15 #include <linux/netdevice.h>
16 #include <linux/capability.h>
17 #include <linux/if_arp.h>
18 #include <linux/kmod.h>
19 #include <linux/vmalloc.h>
20 #include <linux/proc_fs.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/err.h>
25 #include <net/compat.h>
27 #include <asm/uaccess.h>
29 #include <linux/netfilter/x_tables.h>
30 #include <linux/netfilter_arp/arp_tables.h>
31 #include "../../netfilter/xt_repldata.h"
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
35 MODULE_DESCRIPTION("arptables core");
37 /*#define DEBUG_ARP_TABLES*/
38 /*#define DEBUG_ARP_TABLES_USER*/
40 #ifdef DEBUG_ARP_TABLES
41 #define dprintf(format, args...) printk(format , ## args)
43 #define dprintf(format, args...)
46 #ifdef DEBUG_ARP_TABLES_USER
47 #define duprintf(format, args...) printk(format , ## args)
49 #define duprintf(format, args...)
52 #ifdef CONFIG_NETFILTER_DEBUG
53 #define ARP_NF_ASSERT(x) WARN_ON(!(x))
55 #define ARP_NF_ASSERT(x)
58 void *arpt_alloc_initial_table(const struct xt_table *info)
60 return xt_alloc_initial_table(arpt, ARPT);
62 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
64 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
65 const char *hdr_addr, int len)
69 if (len > ARPT_DEV_ADDR_LEN_MAX)
70 len = ARPT_DEV_ADDR_LEN_MAX;
73 for (i = 0; i < len; i++)
74 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
80 * Unfortunately, _b and _mask are not aligned to an int (or long int)
81 * Some arches dont care, unrolling the loop is a win on them.
82 * For other arches, we only have a 16bit alignement.
84 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
86 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
87 unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
89 unsigned long ret = 0;
90 const u16 *a = (const u16 *)_a;
91 const u16 *b = (const u16 *)_b;
92 const u16 *mask = (const u16 *)_mask;
95 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
96 ret |= (a[i] ^ b[i]) & mask[i];
101 /* Returns whether packet matches rule or not. */
102 static inline int arp_packet_match(const struct arphdr *arphdr,
103 struct net_device *dev,
106 const struct arpt_arp *arpinfo)
108 const char *arpptr = (char *)(arphdr + 1);
109 const char *src_devaddr, *tgt_devaddr;
110 __be32 src_ipaddr, tgt_ipaddr;
113 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
115 if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
117 dprintf("ARP operation field mismatch.\n");
118 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
119 arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
123 if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
125 dprintf("ARP hardware address format mismatch.\n");
126 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
127 arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
131 if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
133 dprintf("ARP protocol address format mismatch.\n");
134 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
135 arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
139 if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
141 dprintf("ARP hardware address length mismatch.\n");
142 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
143 arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
147 src_devaddr = arpptr;
148 arpptr += dev->addr_len;
149 memcpy(&src_ipaddr, arpptr, sizeof(u32));
150 arpptr += sizeof(u32);
151 tgt_devaddr = arpptr;
152 arpptr += dev->addr_len;
153 memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
155 if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
156 ARPT_INV_SRCDEVADDR) ||
157 FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
158 ARPT_INV_TGTDEVADDR)) {
159 dprintf("Source or target device address mismatch.\n");
164 if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
166 FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
168 dprintf("Source or target IP address mismatch.\n");
170 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
172 &arpinfo->smsk.s_addr,
173 &arpinfo->src.s_addr,
174 arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
175 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
177 &arpinfo->tmsk.s_addr,
178 &arpinfo->tgt.s_addr,
179 arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
183 /* Look for ifname matches. */
184 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
186 if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
187 dprintf("VIA in mismatch (%s vs %s).%s\n",
188 indev, arpinfo->iniface,
189 arpinfo->invflags & ARPT_INV_VIA_IN ? " (INV)" : "");
193 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
195 if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
196 dprintf("VIA out mismatch (%s vs %s).%s\n",
197 outdev, arpinfo->outiface,
198 arpinfo->invflags & ARPT_INV_VIA_OUT ? " (INV)" : "");
206 static inline int arp_checkentry(const struct arpt_arp *arp)
208 if (arp->flags & ~ARPT_F_MASK) {
209 duprintf("Unknown flag bits set: %08X\n",
210 arp->flags & ~ARPT_F_MASK);
213 if (arp->invflags & ~ARPT_INV_MASK) {
214 duprintf("Unknown invflag bits set: %08X\n",
215 arp->invflags & ~ARPT_INV_MASK);
223 arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
225 net_err_ratelimited("arp_tables: error: '%s'\n",
226 (const char *)par->targinfo);
231 static inline const struct xt_entry_target *
232 arpt_get_target_c(const struct arpt_entry *e)
234 return arpt_get_target((struct arpt_entry *)e);
237 static inline struct arpt_entry *
238 get_entry(const void *base, unsigned int offset)
240 return (struct arpt_entry *)(base + offset);
244 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
246 return (void *)entry + entry->next_offset;
249 unsigned int arpt_do_table(struct sk_buff *skb,
250 const struct nf_hook_state *state,
251 struct xt_table *table)
253 unsigned int hook = state->hook;
254 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
255 unsigned int verdict = NF_DROP;
256 const struct arphdr *arp;
257 struct arpt_entry *e, **jumpstack;
258 const char *indev, *outdev;
259 const void *table_base;
260 unsigned int cpu, stackidx = 0;
261 const struct xt_table_info *private;
262 struct xt_action_param acpar;
265 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
268 indev = state->in ? state->in->name : nulldevname;
269 outdev = state->out ? state->out->name : nulldevname;
272 addend = xt_write_recseq_begin();
273 private = table->private;
274 cpu = smp_processor_id();
276 * Ensure we load private-> members after we've fetched the base
279 smp_read_barrier_depends();
280 table_base = private->entries;
281 jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
283 /* No TEE support for arptables, so no need to switch to alternate
284 * stack. All targets that reenter must return absolute verdicts.
286 e = get_entry(table_base, private->hook_entry[hook]);
288 acpar.net = state->net;
289 acpar.in = state->in;
290 acpar.out = state->out;
291 acpar.hooknum = hook;
292 acpar.family = NFPROTO_ARP;
293 acpar.hotdrop = false;
297 const struct xt_entry_target *t;
298 struct xt_counters *counter;
300 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
301 e = arpt_next_entry(e);
305 counter = xt_get_this_cpu_counter(&e->counters);
306 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
308 t = arpt_get_target_c(e);
310 /* Standard target? */
311 if (!t->u.kernel.target->target) {
314 v = ((struct xt_standard_target *)t)->verdict;
316 /* Pop from stack? */
317 if (v != XT_RETURN) {
318 verdict = (unsigned int)(-v) - 1;
322 e = get_entry(table_base,
323 private->underflow[hook]);
325 e = jumpstack[--stackidx];
326 e = arpt_next_entry(e);
331 != arpt_next_entry(e)) {
332 if (unlikely(stackidx >= private->stacksize)) {
336 jumpstack[stackidx++] = e;
339 e = get_entry(table_base, v);
343 acpar.target = t->u.kernel.target;
344 acpar.targinfo = t->data;
345 verdict = t->u.kernel.target->target(skb, &acpar);
347 /* Target might have changed stuff. */
350 if (verdict == XT_CONTINUE)
351 e = arpt_next_entry(e);
355 } while (!acpar.hotdrop);
356 xt_write_recseq_end(addend);
365 /* All zeroes == unconditional rule. */
366 static inline bool unconditional(const struct arpt_entry *e)
368 static const struct arpt_arp uncond;
370 return e->target_offset == sizeof(struct arpt_entry) &&
371 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
374 /* Figures out from what hook each rule can be called: returns 0 if
375 * there are loops. Puts hook bitmask in comefrom.
377 static int mark_source_chains(const struct xt_table_info *newinfo,
378 unsigned int valid_hooks, void *entry0,
379 unsigned int *offsets)
383 /* No recursion; use packet counter to save back ptrs (reset
384 * to 0 as we leave), and comefrom to save source hook bitmask.
386 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
387 unsigned int pos = newinfo->hook_entry[hook];
389 = (struct arpt_entry *)(entry0 + pos);
391 if (!(valid_hooks & (1 << hook)))
394 /* Set initial back pointer. */
395 e->counters.pcnt = pos;
398 const struct xt_standard_target *t
399 = (void *)arpt_get_target_c(e);
400 int visited = e->comefrom & (1 << hook);
402 if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
403 pr_notice("arptables: loop hook %u pos %u %08X.\n",
404 hook, pos, e->comefrom);
408 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
410 /* Unconditional return/END. */
411 if ((unconditional(e) &&
412 (strcmp(t->target.u.user.name,
413 XT_STANDARD_TARGET) == 0) &&
414 t->verdict < 0) || visited) {
415 unsigned int oldpos, size;
417 if ((strcmp(t->target.u.user.name,
418 XT_STANDARD_TARGET) == 0) &&
419 t->verdict < -NF_MAX_VERDICT - 1) {
420 duprintf("mark_source_chains: bad "
421 "negative verdict (%i)\n",
426 /* Return: backtrack through the last
430 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
432 pos = e->counters.pcnt;
433 e->counters.pcnt = 0;
435 /* We're at the start. */
439 e = (struct arpt_entry *)
441 } while (oldpos == pos + e->next_offset);
444 size = e->next_offset;
445 e = (struct arpt_entry *)
446 (entry0 + pos + size);
447 if (pos + size >= newinfo->size)
449 e->counters.pcnt = pos;
452 int newpos = t->verdict;
454 if (strcmp(t->target.u.user.name,
455 XT_STANDARD_TARGET) == 0 &&
457 if (newpos > newinfo->size -
458 sizeof(struct arpt_entry)) {
459 duprintf("mark_source_chains: "
460 "bad verdict (%i)\n",
465 /* This a jump; chase it. */
466 duprintf("Jump rule %u -> %u\n",
468 if (!xt_find_jump_offset(offsets, newpos,
471 e = (struct arpt_entry *)
474 /* ... this is a fallthru */
475 newpos = pos + e->next_offset;
476 if (newpos >= newinfo->size)
479 e = (struct arpt_entry *)
481 e->counters.pcnt = pos;
486 duprintf("Finished chain %u\n", hook);
491 static int check_target(struct arpt_entry *e, struct net *net, const char *name)
493 struct xt_entry_target *t = arpt_get_target(e);
495 struct xt_tgchk_param par = {
499 .target = t->u.kernel.target,
501 .hook_mask = e->comefrom,
502 .family = NFPROTO_ARP,
505 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
507 duprintf("arp_tables: check failed for `%s'.\n",
508 t->u.kernel.target->name);
515 find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
517 struct xt_percpu_counter_alloc_state *alloc_state)
519 struct xt_entry_target *t;
520 struct xt_target *target;
523 if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
526 t = arpt_get_target(e);
527 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
529 if (IS_ERR(target)) {
530 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
531 ret = PTR_ERR(target);
534 t->u.kernel.target = target;
536 ret = check_target(e, net, name);
541 module_put(t->u.kernel.target->me);
543 xt_percpu_counter_free(&e->counters);
548 static bool check_underflow(const struct arpt_entry *e)
550 const struct xt_entry_target *t;
551 unsigned int verdict;
553 if (!unconditional(e))
555 t = arpt_get_target_c(e);
556 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
558 verdict = ((struct xt_standard_target *)t)->verdict;
559 verdict = -verdict - 1;
560 return verdict == NF_DROP || verdict == NF_ACCEPT;
563 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
564 struct xt_table_info *newinfo,
565 const unsigned char *base,
566 const unsigned char *limit,
567 const unsigned int *hook_entries,
568 const unsigned int *underflows,
569 unsigned int valid_hooks)
574 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
575 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
576 (unsigned char *)e + e->next_offset > limit) {
577 duprintf("Bad offset %p\n", e);
582 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
583 duprintf("checking: element %p size %u\n",
588 if (!arp_checkentry(&e->arp))
591 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
596 /* Check hooks & underflows */
597 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
598 if (!(valid_hooks & (1 << h)))
600 if ((unsigned char *)e - base == hook_entries[h])
601 newinfo->hook_entry[h] = hook_entries[h];
602 if ((unsigned char *)e - base == underflows[h]) {
603 if (!check_underflow(e)) {
604 pr_debug("Underflows must be unconditional and "
605 "use the STANDARD target with "
609 newinfo->underflow[h] = underflows[h];
613 /* Clear counters and comefrom */
614 e->counters = ((struct xt_counters) { 0, 0 });
619 static inline void cleanup_entry(struct arpt_entry *e)
621 struct xt_tgdtor_param par;
622 struct xt_entry_target *t;
624 t = arpt_get_target(e);
625 par.target = t->u.kernel.target;
626 par.targinfo = t->data;
627 par.family = NFPROTO_ARP;
628 if (par.target->destroy != NULL)
629 par.target->destroy(&par);
630 module_put(par.target->me);
631 xt_percpu_counter_free(&e->counters);
634 /* Checks and translates the user-supplied table segment (held in
637 static int translate_table(struct net *net,
638 struct xt_table_info *newinfo,
640 const struct arpt_replace *repl)
642 struct xt_percpu_counter_alloc_state alloc_state = { 0 };
643 struct arpt_entry *iter;
644 unsigned int *offsets;
648 newinfo->size = repl->size;
649 newinfo->number = repl->num_entries;
651 /* Init all hooks to impossible value. */
652 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
653 newinfo->hook_entry[i] = 0xFFFFFFFF;
654 newinfo->underflow[i] = 0xFFFFFFFF;
657 duprintf("translate_table: size %u\n", newinfo->size);
658 offsets = xt_alloc_entry_offsets(newinfo->number);
663 /* Walk through entries, checking offsets. */
664 xt_entry_foreach(iter, entry0, newinfo->size) {
665 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
672 if (i < repl->num_entries)
673 offsets[i] = (void *)iter - entry0;
675 if (strcmp(arpt_get_target(iter)->u.user.name,
676 XT_ERROR_TARGET) == 0)
677 ++newinfo->stacksize;
679 duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
684 if (i != repl->num_entries) {
685 duprintf("translate_table: %u not %u entries\n",
686 i, repl->num_entries);
690 /* Check hooks all assigned */
691 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
692 /* Only hooks which are valid */
693 if (!(repl->valid_hooks & (1 << i)))
695 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
696 duprintf("Invalid hook entry %u %u\n",
697 i, repl->hook_entry[i]);
700 if (newinfo->underflow[i] == 0xFFFFFFFF) {
701 duprintf("Invalid underflow %u %u\n",
702 i, repl->underflow[i]);
707 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
713 /* Finally, each sanity check must pass */
715 xt_entry_foreach(iter, entry0, newinfo->size) {
716 ret = find_check_entry(iter, net, repl->name, repl->size,
724 xt_entry_foreach(iter, entry0, newinfo->size) {
738 static void get_counters(const struct xt_table_info *t,
739 struct xt_counters counters[])
741 struct arpt_entry *iter;
745 for_each_possible_cpu(cpu) {
746 seqcount_t *s = &per_cpu(xt_recseq, cpu);
749 xt_entry_foreach(iter, t->entries, t->size) {
750 struct xt_counters *tmp;
754 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
756 start = read_seqcount_begin(s);
759 } while (read_seqcount_retry(s, start));
761 ADD_COUNTER(counters[i], bcnt, pcnt);
767 static struct xt_counters *alloc_counters(const struct xt_table *table)
769 unsigned int countersize;
770 struct xt_counters *counters;
771 const struct xt_table_info *private = table->private;
773 /* We need atomic snapshot of counters: rest doesn't change
774 * (other than comefrom, which userspace doesn't care
777 countersize = sizeof(struct xt_counters) * private->number;
778 counters = vzalloc(countersize);
780 if (counters == NULL)
781 return ERR_PTR(-ENOMEM);
783 get_counters(private, counters);
788 static int copy_entries_to_user(unsigned int total_size,
789 const struct xt_table *table,
790 void __user *userptr)
792 unsigned int off, num;
793 const struct arpt_entry *e;
794 struct xt_counters *counters;
795 struct xt_table_info *private = table->private;
799 counters = alloc_counters(table);
800 if (IS_ERR(counters))
801 return PTR_ERR(counters);
803 loc_cpu_entry = private->entries;
804 /* ... then copy entire thing ... */
805 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
810 /* FIXME: use iterator macros --RR */
811 /* ... then go back and fix counters and names */
812 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
813 const struct xt_entry_target *t;
815 e = (struct arpt_entry *)(loc_cpu_entry + off);
816 if (copy_to_user(userptr + off
817 + offsetof(struct arpt_entry, counters),
819 sizeof(counters[num])) != 0) {
824 t = arpt_get_target_c(e);
825 if (copy_to_user(userptr + off + e->target_offset
826 + offsetof(struct xt_entry_target,
828 t->u.kernel.target->name,
829 strlen(t->u.kernel.target->name)+1) != 0) {
841 static void compat_standard_from_user(void *dst, const void *src)
843 int v = *(compat_int_t *)src;
846 v += xt_compat_calc_jump(NFPROTO_ARP, v);
847 memcpy(dst, &v, sizeof(v));
850 static int compat_standard_to_user(void __user *dst, const void *src)
852 compat_int_t cv = *(int *)src;
855 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
856 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
859 static int compat_calc_entry(const struct arpt_entry *e,
860 const struct xt_table_info *info,
861 const void *base, struct xt_table_info *newinfo)
863 const struct xt_entry_target *t;
864 unsigned int entry_offset;
867 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
868 entry_offset = (void *)e - base;
870 t = arpt_get_target_c(e);
871 off += xt_compat_target_offset(t->u.kernel.target);
872 newinfo->size -= off;
873 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
877 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
878 if (info->hook_entry[i] &&
879 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
880 newinfo->hook_entry[i] -= off;
881 if (info->underflow[i] &&
882 (e < (struct arpt_entry *)(base + info->underflow[i])))
883 newinfo->underflow[i] -= off;
888 static int compat_table_info(const struct xt_table_info *info,
889 struct xt_table_info *newinfo)
891 struct arpt_entry *iter;
892 const void *loc_cpu_entry;
895 if (!newinfo || !info)
898 /* we dont care about newinfo->entries */
899 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
900 newinfo->initial_entries = 0;
901 loc_cpu_entry = info->entries;
902 xt_compat_init_offsets(NFPROTO_ARP, info->number);
903 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
904 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
912 static int get_info(struct net *net, void __user *user,
913 const int *len, int compat)
915 char name[XT_TABLE_MAXNAMELEN];
919 if (*len != sizeof(struct arpt_getinfo)) {
920 duprintf("length %u != %Zu\n", *len,
921 sizeof(struct arpt_getinfo));
925 if (copy_from_user(name, user, sizeof(name)) != 0)
928 name[XT_TABLE_MAXNAMELEN-1] = '\0';
931 xt_compat_lock(NFPROTO_ARP);
933 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
934 "arptable_%s", name);
935 if (!IS_ERR_OR_NULL(t)) {
936 struct arpt_getinfo info;
937 const struct xt_table_info *private = t->private;
939 struct xt_table_info tmp;
942 ret = compat_table_info(private, &tmp);
943 xt_compat_flush_offsets(NFPROTO_ARP);
947 memset(&info, 0, sizeof(info));
948 info.valid_hooks = t->valid_hooks;
949 memcpy(info.hook_entry, private->hook_entry,
950 sizeof(info.hook_entry));
951 memcpy(info.underflow, private->underflow,
952 sizeof(info.underflow));
953 info.num_entries = private->number;
954 info.size = private->size;
955 strcpy(info.name, name);
957 if (copy_to_user(user, &info, *len) != 0)
964 ret = t ? PTR_ERR(t) : -ENOENT;
967 xt_compat_unlock(NFPROTO_ARP);
972 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
976 struct arpt_get_entries get;
979 if (*len < sizeof(get)) {
980 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
983 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
985 if (*len != sizeof(struct arpt_get_entries) + get.size) {
986 duprintf("get_entries: %u != %Zu\n", *len,
987 sizeof(struct arpt_get_entries) + get.size);
990 get.name[sizeof(get.name) - 1] = '\0';
992 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
993 if (!IS_ERR_OR_NULL(t)) {
994 const struct xt_table_info *private = t->private;
996 duprintf("t->private->number = %u\n",
998 if (get.size == private->size)
999 ret = copy_entries_to_user(private->size,
1000 t, uptr->entrytable);
1002 duprintf("get_entries: I've got %u not %u!\n",
1003 private->size, get.size);
1009 ret = t ? PTR_ERR(t) : -ENOENT;
1014 static int __do_replace(struct net *net, const char *name,
1015 unsigned int valid_hooks,
1016 struct xt_table_info *newinfo,
1017 unsigned int num_counters,
1018 void __user *counters_ptr)
1022 struct xt_table_info *oldinfo;
1023 struct xt_counters *counters;
1024 void *loc_cpu_old_entry;
1025 struct arpt_entry *iter;
1028 counters = vzalloc(num_counters * sizeof(struct xt_counters));
1034 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1035 "arptable_%s", name);
1036 if (IS_ERR_OR_NULL(t)) {
1037 ret = t ? PTR_ERR(t) : -ENOENT;
1038 goto free_newinfo_counters_untrans;
1042 if (valid_hooks != t->valid_hooks) {
1043 duprintf("Valid hook crap: %08X vs %08X\n",
1044 valid_hooks, t->valid_hooks);
1049 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1053 /* Update module usage count based on number of rules */
1054 duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1055 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1056 if ((oldinfo->number > oldinfo->initial_entries) ||
1057 (newinfo->number <= oldinfo->initial_entries))
1059 if ((oldinfo->number > oldinfo->initial_entries) &&
1060 (newinfo->number <= oldinfo->initial_entries))
1063 /* Get the old counters, and synchronize with replace */
1064 get_counters(oldinfo, counters);
1066 /* Decrease module usage counts and free resource */
1067 loc_cpu_old_entry = oldinfo->entries;
1068 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1069 cleanup_entry(iter);
1071 xt_free_table_info(oldinfo);
1072 if (copy_to_user(counters_ptr, counters,
1073 sizeof(struct xt_counters) * num_counters) != 0) {
1074 /* Silent error, can't fail, new table is already in place */
1075 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1084 free_newinfo_counters_untrans:
1090 static int do_replace(struct net *net, const void __user *user,
1094 struct arpt_replace tmp;
1095 struct xt_table_info *newinfo;
1096 void *loc_cpu_entry;
1097 struct arpt_entry *iter;
1099 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1102 /* overflow check */
1103 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1105 if (tmp.num_counters == 0)
1108 tmp.name[sizeof(tmp.name)-1] = 0;
1110 newinfo = xt_alloc_table_info(tmp.size);
1114 loc_cpu_entry = newinfo->entries;
1115 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1121 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
1125 duprintf("arp_tables: Translated table\n");
1127 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1128 tmp.num_counters, tmp.counters);
1130 goto free_newinfo_untrans;
1133 free_newinfo_untrans:
1134 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1135 cleanup_entry(iter);
1137 xt_free_table_info(newinfo);
1141 static int do_add_counters(struct net *net, const void __user *user,
1142 unsigned int len, int compat)
1145 struct xt_counters_info tmp;
1146 struct xt_counters *paddc;
1148 const struct xt_table_info *private;
1150 struct arpt_entry *iter;
1151 unsigned int addend;
1153 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1155 return PTR_ERR(paddc);
1157 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1158 if (IS_ERR_OR_NULL(t)) {
1159 ret = t ? PTR_ERR(t) : -ENOENT;
1164 private = t->private;
1165 if (private->number != tmp.num_counters) {
1167 goto unlock_up_free;
1172 addend = xt_write_recseq_begin();
1173 xt_entry_foreach(iter, private->entries, private->size) {
1174 struct xt_counters *tmp;
1176 tmp = xt_get_this_cpu_counter(&iter->counters);
1177 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1180 xt_write_recseq_end(addend);
1191 #ifdef CONFIG_COMPAT
1192 struct compat_arpt_replace {
1193 char name[XT_TABLE_MAXNAMELEN];
1197 u32 hook_entry[NF_ARP_NUMHOOKS];
1198 u32 underflow[NF_ARP_NUMHOOKS];
1200 compat_uptr_t counters;
1201 struct compat_arpt_entry entries[0];
1204 static inline void compat_release_entry(struct compat_arpt_entry *e)
1206 struct xt_entry_target *t;
1208 t = compat_arpt_get_target(e);
1209 module_put(t->u.kernel.target->me);
1213 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1214 struct xt_table_info *newinfo,
1216 const unsigned char *base,
1217 const unsigned char *limit)
1219 struct xt_entry_target *t;
1220 struct xt_target *target;
1221 unsigned int entry_offset;
1224 duprintf("check_compat_entry_size_and_hooks %p\n", e);
1225 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1226 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1227 (unsigned char *)e + e->next_offset > limit) {
1228 duprintf("Bad offset %p, limit = %p\n", e, limit);
1232 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1233 sizeof(struct compat_xt_entry_target)) {
1234 duprintf("checking: element %p size %u\n",
1239 if (!arp_checkentry(&e->arp))
1242 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1247 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1248 entry_offset = (void *)e - (void *)base;
1250 t = compat_arpt_get_target(e);
1251 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1252 t->u.user.revision);
1253 if (IS_ERR(target)) {
1254 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1256 ret = PTR_ERR(target);
1259 t->u.kernel.target = target;
1261 off += xt_compat_target_offset(target);
1263 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1265 goto release_target;
1270 module_put(t->u.kernel.target->me);
1276 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1278 struct xt_table_info *newinfo, unsigned char *base)
1280 struct xt_entry_target *t;
1281 struct xt_target *target;
1282 struct arpt_entry *de;
1283 unsigned int origsize;
1287 de = (struct arpt_entry *)*dstptr;
1288 memcpy(de, e, sizeof(struct arpt_entry));
1289 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1291 *dstptr += sizeof(struct arpt_entry);
1292 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1294 de->target_offset = e->target_offset - (origsize - *size);
1295 t = compat_arpt_get_target(e);
1296 target = t->u.kernel.target;
1297 xt_compat_target_from_user(t, dstptr, size);
1299 de->next_offset = e->next_offset - (origsize - *size);
1300 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1301 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1302 newinfo->hook_entry[h] -= origsize - *size;
1303 if ((unsigned char *)de - base < newinfo->underflow[h])
1304 newinfo->underflow[h] -= origsize - *size;
1308 static int translate_compat_table(struct net *net,
1309 struct xt_table_info **pinfo,
1311 const struct compat_arpt_replace *compatr)
1314 struct xt_table_info *newinfo, *info;
1315 void *pos, *entry0, *entry1;
1316 struct compat_arpt_entry *iter0;
1317 struct arpt_replace repl;
1323 size = compatr->size;
1324 info->number = compatr->num_entries;
1326 duprintf("translate_compat_table: size %u\n", info->size);
1328 xt_compat_lock(NFPROTO_ARP);
1329 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1330 /* Walk through entries, checking offsets. */
1331 xt_entry_foreach(iter0, entry0, compatr->size) {
1332 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1334 entry0 + compatr->size);
1341 if (j != compatr->num_entries) {
1342 duprintf("translate_compat_table: %u not %u entries\n",
1343 j, compatr->num_entries);
1348 newinfo = xt_alloc_table_info(size);
1352 memset(newinfo->entries, 0, size);
1354 newinfo->number = compatr->num_entries;
1355 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1356 newinfo->hook_entry[i] = compatr->hook_entry[i];
1357 newinfo->underflow[i] = compatr->underflow[i];
1359 entry1 = newinfo->entries;
1361 size = compatr->size;
1362 xt_entry_foreach(iter0, entry0, compatr->size)
1363 compat_copy_entry_from_user(iter0, &pos, &size,
1366 /* all module references in entry0 are now gone */
1368 xt_compat_flush_offsets(NFPROTO_ARP);
1369 xt_compat_unlock(NFPROTO_ARP);
1371 memcpy(&repl, compatr, sizeof(*compatr));
1373 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1374 repl.hook_entry[i] = newinfo->hook_entry[i];
1375 repl.underflow[i] = newinfo->underflow[i];
1378 repl.num_counters = 0;
1379 repl.counters = NULL;
1380 repl.size = newinfo->size;
1381 ret = translate_table(net, newinfo, entry1, &repl);
1387 xt_free_table_info(info);
1391 xt_free_table_info(newinfo);
1394 xt_compat_flush_offsets(NFPROTO_ARP);
1395 xt_compat_unlock(NFPROTO_ARP);
1396 xt_entry_foreach(iter0, entry0, compatr->size) {
1399 compat_release_entry(iter0);
1404 static int compat_do_replace(struct net *net, void __user *user,
1408 struct compat_arpt_replace tmp;
1409 struct xt_table_info *newinfo;
1410 void *loc_cpu_entry;
1411 struct arpt_entry *iter;
1413 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1416 /* overflow check */
1417 if (tmp.size >= INT_MAX / num_possible_cpus())
1419 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1421 if (tmp.num_counters == 0)
1424 tmp.name[sizeof(tmp.name)-1] = 0;
1426 newinfo = xt_alloc_table_info(tmp.size);
1430 loc_cpu_entry = newinfo->entries;
1431 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1436 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1440 duprintf("compat_do_replace: Translated table\n");
1442 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1443 tmp.num_counters, compat_ptr(tmp.counters));
1445 goto free_newinfo_untrans;
1448 free_newinfo_untrans:
1449 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1450 cleanup_entry(iter);
1452 xt_free_table_info(newinfo);
1456 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1461 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1465 case ARPT_SO_SET_REPLACE:
1466 ret = compat_do_replace(sock_net(sk), user, len);
1469 case ARPT_SO_SET_ADD_COUNTERS:
1470 ret = do_add_counters(sock_net(sk), user, len, 1);
1474 duprintf("do_arpt_set_ctl: unknown request %i\n", cmd);
1481 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1482 compat_uint_t *size,
1483 struct xt_counters *counters,
1486 struct xt_entry_target *t;
1487 struct compat_arpt_entry __user *ce;
1488 u_int16_t target_offset, next_offset;
1489 compat_uint_t origsize;
1493 ce = (struct compat_arpt_entry __user *)*dstptr;
1494 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1495 copy_to_user(&ce->counters, &counters[i],
1496 sizeof(counters[i])) != 0)
1499 *dstptr += sizeof(struct compat_arpt_entry);
1500 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1502 target_offset = e->target_offset - (origsize - *size);
1504 t = arpt_get_target(e);
1505 ret = xt_compat_target_to_user(t, dstptr, size);
1508 next_offset = e->next_offset - (origsize - *size);
1509 if (put_user(target_offset, &ce->target_offset) != 0 ||
1510 put_user(next_offset, &ce->next_offset) != 0)
1515 static int compat_copy_entries_to_user(unsigned int total_size,
1516 struct xt_table *table,
1517 void __user *userptr)
1519 struct xt_counters *counters;
1520 const struct xt_table_info *private = table->private;
1525 struct arpt_entry *iter;
1527 counters = alloc_counters(table);
1528 if (IS_ERR(counters))
1529 return PTR_ERR(counters);
1533 xt_entry_foreach(iter, private->entries, total_size) {
1534 ret = compat_copy_entry_to_user(iter, &pos,
1535 &size, counters, i++);
1543 struct compat_arpt_get_entries {
1544 char name[XT_TABLE_MAXNAMELEN];
1546 struct compat_arpt_entry entrytable[0];
1549 static int compat_get_entries(struct net *net,
1550 struct compat_arpt_get_entries __user *uptr,
1554 struct compat_arpt_get_entries get;
1557 if (*len < sizeof(get)) {
1558 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1561 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1563 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1564 duprintf("compat_get_entries: %u != %zu\n",
1565 *len, sizeof(get) + get.size);
1568 get.name[sizeof(get.name) - 1] = '\0';
1570 xt_compat_lock(NFPROTO_ARP);
1571 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1572 if (!IS_ERR_OR_NULL(t)) {
1573 const struct xt_table_info *private = t->private;
1574 struct xt_table_info info;
1576 duprintf("t->private->number = %u\n", private->number);
1577 ret = compat_table_info(private, &info);
1578 if (!ret && get.size == info.size) {
1579 ret = compat_copy_entries_to_user(private->size,
1580 t, uptr->entrytable);
1582 duprintf("compat_get_entries: I've got %u not %u!\n",
1583 private->size, get.size);
1586 xt_compat_flush_offsets(NFPROTO_ARP);
1590 ret = t ? PTR_ERR(t) : -ENOENT;
1592 xt_compat_unlock(NFPROTO_ARP);
1596 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1598 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1603 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1607 case ARPT_SO_GET_INFO:
1608 ret = get_info(sock_net(sk), user, len, 1);
1610 case ARPT_SO_GET_ENTRIES:
1611 ret = compat_get_entries(sock_net(sk), user, len);
1614 ret = do_arpt_get_ctl(sk, cmd, user, len);
1620 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1624 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1628 case ARPT_SO_SET_REPLACE:
1629 ret = do_replace(sock_net(sk), user, len);
1632 case ARPT_SO_SET_ADD_COUNTERS:
1633 ret = do_add_counters(sock_net(sk), user, len, 0);
1637 duprintf("do_arpt_set_ctl: unknown request %i\n", cmd);
1644 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1648 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1652 case ARPT_SO_GET_INFO:
1653 ret = get_info(sock_net(sk), user, len, 0);
1656 case ARPT_SO_GET_ENTRIES:
1657 ret = get_entries(sock_net(sk), user, len);
1660 case ARPT_SO_GET_REVISION_TARGET: {
1661 struct xt_get_revision rev;
1663 if (*len != sizeof(rev)) {
1667 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1671 rev.name[sizeof(rev.name)-1] = 0;
1673 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1674 rev.revision, 1, &ret),
1675 "arpt_%s", rev.name);
1680 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1687 struct xt_table *arpt_register_table(struct net *net,
1688 const struct xt_table *table,
1689 const struct arpt_replace *repl)
1692 struct xt_table_info *newinfo;
1693 struct xt_table_info bootstrap = {0};
1694 void *loc_cpu_entry;
1695 struct xt_table *new_table;
1697 newinfo = xt_alloc_table_info(repl->size);
1703 loc_cpu_entry = newinfo->entries;
1704 memcpy(loc_cpu_entry, repl->entries, repl->size);
1706 ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1707 duprintf("arpt_register_table: translate table gives %d\n", ret);
1711 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1712 if (IS_ERR(new_table)) {
1713 ret = PTR_ERR(new_table);
1719 xt_free_table_info(newinfo);
1721 return ERR_PTR(ret);
1724 void arpt_unregister_table(struct xt_table *table)
1726 struct xt_table_info *private;
1727 void *loc_cpu_entry;
1728 struct module *table_owner = table->me;
1729 struct arpt_entry *iter;
1731 private = xt_unregister_table(table);
1733 /* Decrease module usage counts and free resources */
1734 loc_cpu_entry = private->entries;
1735 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1736 cleanup_entry(iter);
1737 if (private->number > private->initial_entries)
1738 module_put(table_owner);
1739 xt_free_table_info(private);
1742 /* The built-in targets: standard (NULL) and error. */
1743 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1745 .name = XT_STANDARD_TARGET,
1746 .targetsize = sizeof(int),
1747 .family = NFPROTO_ARP,
1748 #ifdef CONFIG_COMPAT
1749 .compatsize = sizeof(compat_int_t),
1750 .compat_from_user = compat_standard_from_user,
1751 .compat_to_user = compat_standard_to_user,
1755 .name = XT_ERROR_TARGET,
1756 .target = arpt_error,
1757 .targetsize = XT_FUNCTION_MAXNAMELEN,
1758 .family = NFPROTO_ARP,
1762 static struct nf_sockopt_ops arpt_sockopts = {
1764 .set_optmin = ARPT_BASE_CTL,
1765 .set_optmax = ARPT_SO_SET_MAX+1,
1766 .set = do_arpt_set_ctl,
1767 #ifdef CONFIG_COMPAT
1768 .compat_set = compat_do_arpt_set_ctl,
1770 .get_optmin = ARPT_BASE_CTL,
1771 .get_optmax = ARPT_SO_GET_MAX+1,
1772 .get = do_arpt_get_ctl,
1773 #ifdef CONFIG_COMPAT
1774 .compat_get = compat_do_arpt_get_ctl,
1776 .owner = THIS_MODULE,
1779 static int __net_init arp_tables_net_init(struct net *net)
1781 return xt_proto_init(net, NFPROTO_ARP);
1784 static void __net_exit arp_tables_net_exit(struct net *net)
1786 xt_proto_fini(net, NFPROTO_ARP);
1789 static struct pernet_operations arp_tables_net_ops = {
1790 .init = arp_tables_net_init,
1791 .exit = arp_tables_net_exit,
1794 static int __init arp_tables_init(void)
1798 ret = register_pernet_subsys(&arp_tables_net_ops);
1802 /* No one else will be downing sem now, so we won't sleep */
1803 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1807 /* Register setsockopt */
1808 ret = nf_register_sockopt(&arpt_sockopts);
1812 printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1816 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1818 unregister_pernet_subsys(&arp_tables_net_ops);
1823 static void __exit arp_tables_fini(void)
1825 nf_unregister_sockopt(&arpt_sockopts);
1826 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1827 unregister_pernet_subsys(&arp_tables_net_ops);
1830 EXPORT_SYMBOL(arpt_register_table);
1831 EXPORT_SYMBOL(arpt_unregister_table);
1832 EXPORT_SYMBOL(arpt_do_table);
1834 module_init(arp_tables_init);
1835 module_exit(arp_tables_fini);