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 jumpstack[stackidx++] = e;
335 e = get_entry(table_base, v);
339 acpar.target = t->u.kernel.target;
340 acpar.targinfo = t->data;
341 verdict = t->u.kernel.target->target(skb, &acpar);
343 /* Target might have changed stuff. */
346 if (verdict == XT_CONTINUE)
347 e = arpt_next_entry(e);
351 } while (!acpar.hotdrop);
352 xt_write_recseq_end(addend);
361 /* All zeroes == unconditional rule. */
362 static inline bool unconditional(const struct arpt_entry *e)
364 static const struct arpt_arp uncond;
366 return e->target_offset == sizeof(struct arpt_entry) &&
367 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
370 static bool find_jump_target(const struct xt_table_info *t,
371 const struct arpt_entry *target)
373 struct arpt_entry *iter;
375 xt_entry_foreach(iter, t->entries, t->size) {
382 /* Figures out from what hook each rule can be called: returns 0 if
383 * there are loops. Puts hook bitmask in comefrom.
385 static int mark_source_chains(const struct xt_table_info *newinfo,
386 unsigned int valid_hooks, void *entry0)
390 /* No recursion; use packet counter to save back ptrs (reset
391 * to 0 as we leave), and comefrom to save source hook bitmask.
393 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
394 unsigned int pos = newinfo->hook_entry[hook];
396 = (struct arpt_entry *)(entry0 + pos);
398 if (!(valid_hooks & (1 << hook)))
401 /* Set initial back pointer. */
402 e->counters.pcnt = pos;
405 const struct xt_standard_target *t
406 = (void *)arpt_get_target_c(e);
407 int visited = e->comefrom & (1 << hook);
409 if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
410 pr_notice("arptables: loop hook %u pos %u %08X.\n",
411 hook, pos, e->comefrom);
415 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
417 /* Unconditional return/END. */
418 if ((unconditional(e) &&
419 (strcmp(t->target.u.user.name,
420 XT_STANDARD_TARGET) == 0) &&
421 t->verdict < 0) || visited) {
422 unsigned int oldpos, size;
424 if ((strcmp(t->target.u.user.name,
425 XT_STANDARD_TARGET) == 0) &&
426 t->verdict < -NF_MAX_VERDICT - 1) {
427 duprintf("mark_source_chains: bad "
428 "negative verdict (%i)\n",
433 /* Return: backtrack through the last
437 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
439 pos = e->counters.pcnt;
440 e->counters.pcnt = 0;
442 /* We're at the start. */
446 e = (struct arpt_entry *)
448 } while (oldpos == pos + e->next_offset);
451 size = e->next_offset;
452 e = (struct arpt_entry *)
453 (entry0 + pos + size);
454 if (pos + size >= newinfo->size)
456 e->counters.pcnt = pos;
459 int newpos = t->verdict;
461 if (strcmp(t->target.u.user.name,
462 XT_STANDARD_TARGET) == 0 &&
464 if (newpos > newinfo->size -
465 sizeof(struct arpt_entry)) {
466 duprintf("mark_source_chains: "
467 "bad verdict (%i)\n",
472 /* This a jump; chase it. */
473 duprintf("Jump rule %u -> %u\n",
475 e = (struct arpt_entry *)
477 if (!find_jump_target(newinfo, e))
480 /* ... this is a fallthru */
481 newpos = pos + e->next_offset;
482 if (newpos >= newinfo->size)
485 e = (struct arpt_entry *)
487 e->counters.pcnt = pos;
492 duprintf("Finished chain %u\n", hook);
497 static inline int check_target(struct arpt_entry *e, const char *name)
499 struct xt_entry_target *t = arpt_get_target(e);
501 struct xt_tgchk_param par = {
504 .target = t->u.kernel.target,
506 .hook_mask = e->comefrom,
507 .family = NFPROTO_ARP,
510 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
512 duprintf("arp_tables: check failed for `%s'.\n",
513 t->u.kernel.target->name);
520 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
522 struct xt_entry_target *t;
523 struct xt_target *target;
526 e->counters.pcnt = xt_percpu_counter_alloc();
527 if (IS_ERR_VALUE(e->counters.pcnt))
530 t = arpt_get_target(e);
531 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
533 if (IS_ERR(target)) {
534 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
535 ret = PTR_ERR(target);
538 t->u.kernel.target = target;
540 ret = check_target(e, name);
545 module_put(t->u.kernel.target->me);
547 xt_percpu_counter_free(e->counters.pcnt);
552 static bool check_underflow(const struct arpt_entry *e)
554 const struct xt_entry_target *t;
555 unsigned int verdict;
557 if (!unconditional(e))
559 t = arpt_get_target_c(e);
560 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
562 verdict = ((struct xt_standard_target *)t)->verdict;
563 verdict = -verdict - 1;
564 return verdict == NF_DROP || verdict == NF_ACCEPT;
567 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
568 struct xt_table_info *newinfo,
569 const unsigned char *base,
570 const unsigned char *limit,
571 const unsigned int *hook_entries,
572 const unsigned int *underflows,
573 unsigned int valid_hooks)
578 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
579 (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
580 (unsigned char *)e + e->next_offset > limit) {
581 duprintf("Bad offset %p\n", e);
586 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
587 duprintf("checking: element %p size %u\n",
592 if (!arp_checkentry(&e->arp))
595 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
600 /* Check hooks & underflows */
601 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
602 if (!(valid_hooks & (1 << h)))
604 if ((unsigned char *)e - base == hook_entries[h])
605 newinfo->hook_entry[h] = hook_entries[h];
606 if ((unsigned char *)e - base == underflows[h]) {
607 if (!check_underflow(e)) {
608 pr_debug("Underflows must be unconditional and "
609 "use the STANDARD target with "
613 newinfo->underflow[h] = underflows[h];
617 /* Clear counters and comefrom */
618 e->counters = ((struct xt_counters) { 0, 0 });
623 static inline void cleanup_entry(struct arpt_entry *e)
625 struct xt_tgdtor_param par;
626 struct xt_entry_target *t;
628 t = arpt_get_target(e);
629 par.target = t->u.kernel.target;
630 par.targinfo = t->data;
631 par.family = NFPROTO_ARP;
632 if (par.target->destroy != NULL)
633 par.target->destroy(&par);
634 module_put(par.target->me);
635 xt_percpu_counter_free(e->counters.pcnt);
638 /* Checks and translates the user-supplied table segment (held in
641 static int translate_table(struct xt_table_info *newinfo, void *entry0,
642 const struct arpt_replace *repl)
644 struct arpt_entry *iter;
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);
660 /* Walk through entries, checking offsets. */
661 xt_entry_foreach(iter, entry0, newinfo->size) {
662 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
670 if (strcmp(arpt_get_target(iter)->u.user.name,
671 XT_ERROR_TARGET) == 0)
672 ++newinfo->stacksize;
674 duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
678 if (i != repl->num_entries) {
679 duprintf("translate_table: %u not %u entries\n",
680 i, repl->num_entries);
684 /* Check hooks all assigned */
685 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
686 /* Only hooks which are valid */
687 if (!(repl->valid_hooks & (1 << i)))
689 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
690 duprintf("Invalid hook entry %u %u\n",
691 i, repl->hook_entry[i]);
694 if (newinfo->underflow[i] == 0xFFFFFFFF) {
695 duprintf("Invalid underflow %u %u\n",
696 i, repl->underflow[i]);
701 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
704 /* Finally, each sanity check must pass */
706 xt_entry_foreach(iter, entry0, newinfo->size) {
707 ret = find_check_entry(iter, repl->name, repl->size);
714 xt_entry_foreach(iter, entry0, newinfo->size) {
725 static void get_counters(const struct xt_table_info *t,
726 struct xt_counters counters[])
728 struct arpt_entry *iter;
732 for_each_possible_cpu(cpu) {
733 seqcount_t *s = &per_cpu(xt_recseq, cpu);
736 xt_entry_foreach(iter, t->entries, t->size) {
737 struct xt_counters *tmp;
741 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
743 start = read_seqcount_begin(s);
746 } while (read_seqcount_retry(s, start));
748 ADD_COUNTER(counters[i], bcnt, pcnt);
754 static struct xt_counters *alloc_counters(const struct xt_table *table)
756 unsigned int countersize;
757 struct xt_counters *counters;
758 const struct xt_table_info *private = table->private;
760 /* We need atomic snapshot of counters: rest doesn't change
761 * (other than comefrom, which userspace doesn't care
764 countersize = sizeof(struct xt_counters) * private->number;
765 counters = vzalloc(countersize);
767 if (counters == NULL)
768 return ERR_PTR(-ENOMEM);
770 get_counters(private, counters);
775 static int copy_entries_to_user(unsigned int total_size,
776 const struct xt_table *table,
777 void __user *userptr)
779 unsigned int off, num;
780 const struct arpt_entry *e;
781 struct xt_counters *counters;
782 struct xt_table_info *private = table->private;
786 counters = alloc_counters(table);
787 if (IS_ERR(counters))
788 return PTR_ERR(counters);
790 loc_cpu_entry = private->entries;
791 /* ... then copy entire thing ... */
792 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
797 /* FIXME: use iterator macros --RR */
798 /* ... then go back and fix counters and names */
799 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
800 const struct xt_entry_target *t;
802 e = (struct arpt_entry *)(loc_cpu_entry + off);
803 if (copy_to_user(userptr + off
804 + offsetof(struct arpt_entry, counters),
806 sizeof(counters[num])) != 0) {
811 t = arpt_get_target_c(e);
812 if (copy_to_user(userptr + off + e->target_offset
813 + offsetof(struct xt_entry_target,
815 t->u.kernel.target->name,
816 strlen(t->u.kernel.target->name)+1) != 0) {
828 static void compat_standard_from_user(void *dst, const void *src)
830 int v = *(compat_int_t *)src;
833 v += xt_compat_calc_jump(NFPROTO_ARP, v);
834 memcpy(dst, &v, sizeof(v));
837 static int compat_standard_to_user(void __user *dst, const void *src)
839 compat_int_t cv = *(int *)src;
842 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
843 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
846 static int compat_calc_entry(const struct arpt_entry *e,
847 const struct xt_table_info *info,
848 const void *base, struct xt_table_info *newinfo)
850 const struct xt_entry_target *t;
851 unsigned int entry_offset;
854 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
855 entry_offset = (void *)e - base;
857 t = arpt_get_target_c(e);
858 off += xt_compat_target_offset(t->u.kernel.target);
859 newinfo->size -= off;
860 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
864 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
865 if (info->hook_entry[i] &&
866 (e < (struct arpt_entry *)(base + info->hook_entry[i])))
867 newinfo->hook_entry[i] -= off;
868 if (info->underflow[i] &&
869 (e < (struct arpt_entry *)(base + info->underflow[i])))
870 newinfo->underflow[i] -= off;
875 static int compat_table_info(const struct xt_table_info *info,
876 struct xt_table_info *newinfo)
878 struct arpt_entry *iter;
879 const void *loc_cpu_entry;
882 if (!newinfo || !info)
885 /* we dont care about newinfo->entries */
886 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
887 newinfo->initial_entries = 0;
888 loc_cpu_entry = info->entries;
889 xt_compat_init_offsets(NFPROTO_ARP, info->number);
890 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
891 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
899 static int get_info(struct net *net, void __user *user,
900 const int *len, int compat)
902 char name[XT_TABLE_MAXNAMELEN];
906 if (*len != sizeof(struct arpt_getinfo)) {
907 duprintf("length %u != %Zu\n", *len,
908 sizeof(struct arpt_getinfo));
912 if (copy_from_user(name, user, sizeof(name)) != 0)
915 name[XT_TABLE_MAXNAMELEN-1] = '\0';
918 xt_compat_lock(NFPROTO_ARP);
920 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
921 "arptable_%s", name);
922 if (!IS_ERR_OR_NULL(t)) {
923 struct arpt_getinfo info;
924 const struct xt_table_info *private = t->private;
926 struct xt_table_info tmp;
929 ret = compat_table_info(private, &tmp);
930 xt_compat_flush_offsets(NFPROTO_ARP);
934 memset(&info, 0, sizeof(info));
935 info.valid_hooks = t->valid_hooks;
936 memcpy(info.hook_entry, private->hook_entry,
937 sizeof(info.hook_entry));
938 memcpy(info.underflow, private->underflow,
939 sizeof(info.underflow));
940 info.num_entries = private->number;
941 info.size = private->size;
942 strcpy(info.name, name);
944 if (copy_to_user(user, &info, *len) != 0)
951 ret = t ? PTR_ERR(t) : -ENOENT;
954 xt_compat_unlock(NFPROTO_ARP);
959 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
963 struct arpt_get_entries get;
966 if (*len < sizeof(get)) {
967 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
970 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
972 if (*len != sizeof(struct arpt_get_entries) + get.size) {
973 duprintf("get_entries: %u != %Zu\n", *len,
974 sizeof(struct arpt_get_entries) + get.size);
978 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
979 if (!IS_ERR_OR_NULL(t)) {
980 const struct xt_table_info *private = t->private;
982 duprintf("t->private->number = %u\n",
984 if (get.size == private->size)
985 ret = copy_entries_to_user(private->size,
986 t, uptr->entrytable);
988 duprintf("get_entries: I've got %u not %u!\n",
989 private->size, get.size);
995 ret = t ? PTR_ERR(t) : -ENOENT;
1000 static int __do_replace(struct net *net, const char *name,
1001 unsigned int valid_hooks,
1002 struct xt_table_info *newinfo,
1003 unsigned int num_counters,
1004 void __user *counters_ptr)
1008 struct xt_table_info *oldinfo;
1009 struct xt_counters *counters;
1010 void *loc_cpu_old_entry;
1011 struct arpt_entry *iter;
1014 counters = vzalloc(num_counters * sizeof(struct xt_counters));
1020 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1021 "arptable_%s", name);
1022 if (IS_ERR_OR_NULL(t)) {
1023 ret = t ? PTR_ERR(t) : -ENOENT;
1024 goto free_newinfo_counters_untrans;
1028 if (valid_hooks != t->valid_hooks) {
1029 duprintf("Valid hook crap: %08X vs %08X\n",
1030 valid_hooks, t->valid_hooks);
1035 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1039 /* Update module usage count based on number of rules */
1040 duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1041 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1042 if ((oldinfo->number > oldinfo->initial_entries) ||
1043 (newinfo->number <= oldinfo->initial_entries))
1045 if ((oldinfo->number > oldinfo->initial_entries) &&
1046 (newinfo->number <= oldinfo->initial_entries))
1049 /* Get the old counters, and synchronize with replace */
1050 get_counters(oldinfo, counters);
1052 /* Decrease module usage counts and free resource */
1053 loc_cpu_old_entry = oldinfo->entries;
1054 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1055 cleanup_entry(iter);
1057 xt_free_table_info(oldinfo);
1058 if (copy_to_user(counters_ptr, counters,
1059 sizeof(struct xt_counters) * num_counters) != 0) {
1060 /* Silent error, can't fail, new table is already in place */
1061 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
1070 free_newinfo_counters_untrans:
1076 static int do_replace(struct net *net, const void __user *user,
1080 struct arpt_replace tmp;
1081 struct xt_table_info *newinfo;
1082 void *loc_cpu_entry;
1083 struct arpt_entry *iter;
1085 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1088 /* overflow check */
1089 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1091 if (tmp.num_counters == 0)
1094 tmp.name[sizeof(tmp.name)-1] = 0;
1096 newinfo = xt_alloc_table_info(tmp.size);
1100 loc_cpu_entry = newinfo->entries;
1101 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1107 ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1111 duprintf("arp_tables: Translated table\n");
1113 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1114 tmp.num_counters, tmp.counters);
1116 goto free_newinfo_untrans;
1119 free_newinfo_untrans:
1120 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1121 cleanup_entry(iter);
1123 xt_free_table_info(newinfo);
1127 static int do_add_counters(struct net *net, const void __user *user,
1128 unsigned int len, int compat)
1131 struct xt_counters_info tmp;
1132 struct xt_counters *paddc;
1134 const struct xt_table_info *private;
1136 struct arpt_entry *iter;
1137 unsigned int addend;
1139 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1141 return PTR_ERR(paddc);
1143 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
1144 if (IS_ERR_OR_NULL(t)) {
1145 ret = t ? PTR_ERR(t) : -ENOENT;
1150 private = t->private;
1151 if (private->number != tmp.num_counters) {
1153 goto unlock_up_free;
1158 addend = xt_write_recseq_begin();
1159 xt_entry_foreach(iter, private->entries, private->size) {
1160 struct xt_counters *tmp;
1162 tmp = xt_get_this_cpu_counter(&iter->counters);
1163 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1166 xt_write_recseq_end(addend);
1177 #ifdef CONFIG_COMPAT
1178 struct compat_arpt_replace {
1179 char name[XT_TABLE_MAXNAMELEN];
1183 u32 hook_entry[NF_ARP_NUMHOOKS];
1184 u32 underflow[NF_ARP_NUMHOOKS];
1186 compat_uptr_t counters;
1187 struct compat_arpt_entry entries[0];
1190 static inline void compat_release_entry(struct compat_arpt_entry *e)
1192 struct xt_entry_target *t;
1194 t = compat_arpt_get_target(e);
1195 module_put(t->u.kernel.target->me);
1199 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1200 struct xt_table_info *newinfo,
1202 const unsigned char *base,
1203 const unsigned char *limit)
1205 struct xt_entry_target *t;
1206 struct xt_target *target;
1207 unsigned int entry_offset;
1210 duprintf("check_compat_entry_size_and_hooks %p\n", e);
1211 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1212 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
1213 (unsigned char *)e + e->next_offset > limit) {
1214 duprintf("Bad offset %p, limit = %p\n", e, limit);
1218 if (e->next_offset < sizeof(struct compat_arpt_entry) +
1219 sizeof(struct compat_xt_entry_target)) {
1220 duprintf("checking: element %p size %u\n",
1225 if (!arp_checkentry(&e->arp))
1228 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
1233 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1234 entry_offset = (void *)e - (void *)base;
1236 t = compat_arpt_get_target(e);
1237 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1238 t->u.user.revision);
1239 if (IS_ERR(target)) {
1240 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1242 ret = PTR_ERR(target);
1245 t->u.kernel.target = target;
1247 off += xt_compat_target_offset(target);
1249 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1251 goto release_target;
1256 module_put(t->u.kernel.target->me);
1262 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1264 struct xt_table_info *newinfo, unsigned char *base)
1266 struct xt_entry_target *t;
1267 struct xt_target *target;
1268 struct arpt_entry *de;
1269 unsigned int origsize;
1273 de = (struct arpt_entry *)*dstptr;
1274 memcpy(de, e, sizeof(struct arpt_entry));
1275 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1277 *dstptr += sizeof(struct arpt_entry);
1278 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1280 de->target_offset = e->target_offset - (origsize - *size);
1281 t = compat_arpt_get_target(e);
1282 target = t->u.kernel.target;
1283 xt_compat_target_from_user(t, dstptr, size);
1285 de->next_offset = e->next_offset - (origsize - *size);
1286 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1287 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1288 newinfo->hook_entry[h] -= origsize - *size;
1289 if ((unsigned char *)de - base < newinfo->underflow[h])
1290 newinfo->underflow[h] -= origsize - *size;
1294 static int translate_compat_table(struct xt_table_info **pinfo,
1296 const struct compat_arpt_replace *compatr)
1299 struct xt_table_info *newinfo, *info;
1300 void *pos, *entry0, *entry1;
1301 struct compat_arpt_entry *iter0;
1302 struct arpt_replace repl;
1308 size = compatr->size;
1309 info->number = compatr->num_entries;
1311 duprintf("translate_compat_table: size %u\n", info->size);
1313 xt_compat_lock(NFPROTO_ARP);
1314 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
1315 /* Walk through entries, checking offsets. */
1316 xt_entry_foreach(iter0, entry0, compatr->size) {
1317 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1319 entry0 + compatr->size);
1326 if (j != compatr->num_entries) {
1327 duprintf("translate_compat_table: %u not %u entries\n",
1328 j, compatr->num_entries);
1333 newinfo = xt_alloc_table_info(size);
1337 newinfo->number = compatr->num_entries;
1338 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1339 newinfo->hook_entry[i] = info->hook_entry[i];
1340 newinfo->underflow[i] = info->underflow[i];
1342 entry1 = newinfo->entries;
1344 size = compatr->size;
1345 xt_entry_foreach(iter0, entry0, compatr->size)
1346 compat_copy_entry_from_user(iter0, &pos, &size,
1349 /* all module references in entry0 are now gone */
1351 xt_compat_flush_offsets(NFPROTO_ARP);
1352 xt_compat_unlock(NFPROTO_ARP);
1354 memcpy(&repl, compatr, sizeof(*compatr));
1356 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1357 repl.hook_entry[i] = newinfo->hook_entry[i];
1358 repl.underflow[i] = newinfo->underflow[i];
1361 repl.num_counters = 0;
1362 repl.counters = NULL;
1363 repl.size = newinfo->size;
1364 ret = translate_table(newinfo, entry1, &repl);
1370 xt_free_table_info(info);
1374 xt_free_table_info(newinfo);
1377 xt_compat_flush_offsets(NFPROTO_ARP);
1378 xt_compat_unlock(NFPROTO_ARP);
1379 xt_entry_foreach(iter0, entry0, compatr->size) {
1382 compat_release_entry(iter0);
1387 static int compat_do_replace(struct net *net, void __user *user,
1391 struct compat_arpt_replace tmp;
1392 struct xt_table_info *newinfo;
1393 void *loc_cpu_entry;
1394 struct arpt_entry *iter;
1396 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1399 /* overflow check */
1400 if (tmp.size >= INT_MAX / num_possible_cpus())
1402 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1404 if (tmp.num_counters == 0)
1407 tmp.name[sizeof(tmp.name)-1] = 0;
1409 newinfo = xt_alloc_table_info(tmp.size);
1413 loc_cpu_entry = newinfo->entries;
1414 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1419 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp);
1423 duprintf("compat_do_replace: Translated table\n");
1425 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1426 tmp.num_counters, compat_ptr(tmp.counters));
1428 goto free_newinfo_untrans;
1431 free_newinfo_untrans:
1432 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1433 cleanup_entry(iter);
1435 xt_free_table_info(newinfo);
1439 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1444 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1448 case ARPT_SO_SET_REPLACE:
1449 ret = compat_do_replace(sock_net(sk), user, len);
1452 case ARPT_SO_SET_ADD_COUNTERS:
1453 ret = do_add_counters(sock_net(sk), user, len, 1);
1457 duprintf("do_arpt_set_ctl: unknown request %i\n", cmd);
1464 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1465 compat_uint_t *size,
1466 struct xt_counters *counters,
1469 struct xt_entry_target *t;
1470 struct compat_arpt_entry __user *ce;
1471 u_int16_t target_offset, next_offset;
1472 compat_uint_t origsize;
1476 ce = (struct compat_arpt_entry __user *)*dstptr;
1477 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1478 copy_to_user(&ce->counters, &counters[i],
1479 sizeof(counters[i])) != 0)
1482 *dstptr += sizeof(struct compat_arpt_entry);
1483 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1485 target_offset = e->target_offset - (origsize - *size);
1487 t = arpt_get_target(e);
1488 ret = xt_compat_target_to_user(t, dstptr, size);
1491 next_offset = e->next_offset - (origsize - *size);
1492 if (put_user(target_offset, &ce->target_offset) != 0 ||
1493 put_user(next_offset, &ce->next_offset) != 0)
1498 static int compat_copy_entries_to_user(unsigned int total_size,
1499 struct xt_table *table,
1500 void __user *userptr)
1502 struct xt_counters *counters;
1503 const struct xt_table_info *private = table->private;
1508 struct arpt_entry *iter;
1510 counters = alloc_counters(table);
1511 if (IS_ERR(counters))
1512 return PTR_ERR(counters);
1516 xt_entry_foreach(iter, private->entries, total_size) {
1517 ret = compat_copy_entry_to_user(iter, &pos,
1518 &size, counters, i++);
1526 struct compat_arpt_get_entries {
1527 char name[XT_TABLE_MAXNAMELEN];
1529 struct compat_arpt_entry entrytable[0];
1532 static int compat_get_entries(struct net *net,
1533 struct compat_arpt_get_entries __user *uptr,
1537 struct compat_arpt_get_entries get;
1540 if (*len < sizeof(get)) {
1541 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1544 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1546 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1547 duprintf("compat_get_entries: %u != %zu\n",
1548 *len, sizeof(get) + get.size);
1552 xt_compat_lock(NFPROTO_ARP);
1553 t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1554 if (!IS_ERR_OR_NULL(t)) {
1555 const struct xt_table_info *private = t->private;
1556 struct xt_table_info info;
1558 duprintf("t->private->number = %u\n", private->number);
1559 ret = compat_table_info(private, &info);
1560 if (!ret && get.size == info.size) {
1561 ret = compat_copy_entries_to_user(private->size,
1562 t, uptr->entrytable);
1564 duprintf("compat_get_entries: I've got %u not %u!\n",
1565 private->size, get.size);
1568 xt_compat_flush_offsets(NFPROTO_ARP);
1572 ret = t ? PTR_ERR(t) : -ENOENT;
1574 xt_compat_unlock(NFPROTO_ARP);
1578 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1580 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1585 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1589 case ARPT_SO_GET_INFO:
1590 ret = get_info(sock_net(sk), user, len, 1);
1592 case ARPT_SO_GET_ENTRIES:
1593 ret = compat_get_entries(sock_net(sk), user, len);
1596 ret = do_arpt_get_ctl(sk, cmd, user, len);
1602 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1606 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1610 case ARPT_SO_SET_REPLACE:
1611 ret = do_replace(sock_net(sk), user, len);
1614 case ARPT_SO_SET_ADD_COUNTERS:
1615 ret = do_add_counters(sock_net(sk), user, len, 0);
1619 duprintf("do_arpt_set_ctl: unknown request %i\n", cmd);
1626 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1630 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1634 case ARPT_SO_GET_INFO:
1635 ret = get_info(sock_net(sk), user, len, 0);
1638 case ARPT_SO_GET_ENTRIES:
1639 ret = get_entries(sock_net(sk), user, len);
1642 case ARPT_SO_GET_REVISION_TARGET: {
1643 struct xt_get_revision rev;
1645 if (*len != sizeof(rev)) {
1649 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1653 rev.name[sizeof(rev.name)-1] = 0;
1655 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1656 rev.revision, 1, &ret),
1657 "arpt_%s", rev.name);
1662 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1669 struct xt_table *arpt_register_table(struct net *net,
1670 const struct xt_table *table,
1671 const struct arpt_replace *repl)
1674 struct xt_table_info *newinfo;
1675 struct xt_table_info bootstrap = {0};
1676 void *loc_cpu_entry;
1677 struct xt_table *new_table;
1679 newinfo = xt_alloc_table_info(repl->size);
1685 loc_cpu_entry = newinfo->entries;
1686 memcpy(loc_cpu_entry, repl->entries, repl->size);
1688 ret = translate_table(newinfo, loc_cpu_entry, repl);
1689 duprintf("arpt_register_table: translate table gives %d\n", ret);
1693 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1694 if (IS_ERR(new_table)) {
1695 ret = PTR_ERR(new_table);
1701 xt_free_table_info(newinfo);
1703 return ERR_PTR(ret);
1706 void arpt_unregister_table(struct xt_table *table)
1708 struct xt_table_info *private;
1709 void *loc_cpu_entry;
1710 struct module *table_owner = table->me;
1711 struct arpt_entry *iter;
1713 private = xt_unregister_table(table);
1715 /* Decrease module usage counts and free resources */
1716 loc_cpu_entry = private->entries;
1717 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1718 cleanup_entry(iter);
1719 if (private->number > private->initial_entries)
1720 module_put(table_owner);
1721 xt_free_table_info(private);
1724 /* The built-in targets: standard (NULL) and error. */
1725 static struct xt_target arpt_builtin_tg[] __read_mostly = {
1727 .name = XT_STANDARD_TARGET,
1728 .targetsize = sizeof(int),
1729 .family = NFPROTO_ARP,
1730 #ifdef CONFIG_COMPAT
1731 .compatsize = sizeof(compat_int_t),
1732 .compat_from_user = compat_standard_from_user,
1733 .compat_to_user = compat_standard_to_user,
1737 .name = XT_ERROR_TARGET,
1738 .target = arpt_error,
1739 .targetsize = XT_FUNCTION_MAXNAMELEN,
1740 .family = NFPROTO_ARP,
1744 static struct nf_sockopt_ops arpt_sockopts = {
1746 .set_optmin = ARPT_BASE_CTL,
1747 .set_optmax = ARPT_SO_SET_MAX+1,
1748 .set = do_arpt_set_ctl,
1749 #ifdef CONFIG_COMPAT
1750 .compat_set = compat_do_arpt_set_ctl,
1752 .get_optmin = ARPT_BASE_CTL,
1753 .get_optmax = ARPT_SO_GET_MAX+1,
1754 .get = do_arpt_get_ctl,
1755 #ifdef CONFIG_COMPAT
1756 .compat_get = compat_do_arpt_get_ctl,
1758 .owner = THIS_MODULE,
1761 static int __net_init arp_tables_net_init(struct net *net)
1763 return xt_proto_init(net, NFPROTO_ARP);
1766 static void __net_exit arp_tables_net_exit(struct net *net)
1768 xt_proto_fini(net, NFPROTO_ARP);
1771 static struct pernet_operations arp_tables_net_ops = {
1772 .init = arp_tables_net_init,
1773 .exit = arp_tables_net_exit,
1776 static int __init arp_tables_init(void)
1780 ret = register_pernet_subsys(&arp_tables_net_ops);
1784 /* No one else will be downing sem now, so we won't sleep */
1785 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1789 /* Register setsockopt */
1790 ret = nf_register_sockopt(&arpt_sockopts);
1794 printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1798 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1800 unregister_pernet_subsys(&arp_tables_net_ops);
1805 static void __exit arp_tables_fini(void)
1807 nf_unregister_sockopt(&arpt_sockopts);
1808 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1809 unregister_pernet_subsys(&arp_tables_net_ops);
1812 EXPORT_SYMBOL(arpt_register_table);
1813 EXPORT_SYMBOL(arpt_unregister_table);
1814 EXPORT_SYMBOL(arpt_do_table);
1816 module_init(arp_tables_init);
1817 module_exit(arp_tables_fini);