mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-10-20 10:28:24 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
228 lines
5.5 KiB
C
228 lines
5.5 KiB
C
/*
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* ebt_among
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*
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* Authors:
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* Grzegorz Borowiak <grzes@gnu.univ.gda.pl>
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*
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* August, 2003
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*
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*/
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_bridge/ebt_among.h>
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#include <linux/ip.h>
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#include <linux/if_arp.h>
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#include <linux/module.h>
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static int ebt_mac_wormhash_contains(const struct ebt_mac_wormhash *wh,
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const char *mac, uint32_t ip)
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{
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/* You may be puzzled as to how this code works.
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* Some tricks were used, refer to
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* include/linux/netfilter_bridge/ebt_among.h
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* as there you can find a solution of this mystery.
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*/
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const struct ebt_mac_wormhash_tuple *p;
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int start, limit, i;
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uint32_t cmp[2] = { 0, 0 };
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int key = (const unsigned char) mac[5];
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memcpy(((char *) cmp) + 2, mac, 6);
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start = wh->table[key];
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limit = wh->table[key + 1];
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if (ip) {
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for (i = start; i < limit; i++) {
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p = &wh->pool[i];
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if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0]) {
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if (p->ip == 0 || p->ip == ip) {
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return 1;
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}
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}
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}
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} else {
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for (i = start; i < limit; i++) {
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p = &wh->pool[i];
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if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0]) {
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if (p->ip == 0) {
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return 1;
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}
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}
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}
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}
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return 0;
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}
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static int ebt_mac_wormhash_check_integrity(const struct ebt_mac_wormhash
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*wh)
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{
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int i;
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for (i = 0; i < 256; i++) {
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if (wh->table[i] > wh->table[i + 1])
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return -0x100 - i;
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if (wh->table[i] < 0)
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return -0x200 - i;
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if (wh->table[i] > wh->poolsize)
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return -0x300 - i;
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}
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if (wh->table[256] > wh->poolsize)
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return -0xc00;
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return 0;
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}
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static int get_ip_dst(const struct sk_buff *skb, uint32_t *addr)
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{
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if (eth_hdr(skb)->h_proto == htons(ETH_P_IP)) {
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struct iphdr _iph, *ih;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (ih == NULL)
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return -1;
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*addr = ih->daddr;
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} else if (eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
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struct arphdr _arph, *ah;
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uint32_t buf, *bp;
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ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
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if (ah == NULL ||
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ah->ar_pln != sizeof(uint32_t) ||
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ah->ar_hln != ETH_ALEN)
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return -1;
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bp = skb_header_pointer(skb, sizeof(struct arphdr) +
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2 * ETH_ALEN + sizeof(uint32_t),
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sizeof(uint32_t), &buf);
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if (bp == NULL)
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return -1;
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*addr = *bp;
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}
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return 0;
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}
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static int get_ip_src(const struct sk_buff *skb, uint32_t *addr)
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{
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if (eth_hdr(skb)->h_proto == htons(ETH_P_IP)) {
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struct iphdr _iph, *ih;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (ih == NULL)
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return -1;
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*addr = ih->saddr;
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} else if (eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
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struct arphdr _arph, *ah;
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uint32_t buf, *bp;
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ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
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if (ah == NULL ||
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ah->ar_pln != sizeof(uint32_t) ||
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ah->ar_hln != ETH_ALEN)
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return -1;
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bp = skb_header_pointer(skb, sizeof(struct arphdr) +
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ETH_ALEN, sizeof(uint32_t), &buf);
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if (bp == NULL)
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return -1;
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*addr = *bp;
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}
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return 0;
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}
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static int ebt_filter_among(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out, const void *data,
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unsigned int datalen)
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{
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struct ebt_among_info *info = (struct ebt_among_info *) data;
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const char *dmac, *smac;
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const struct ebt_mac_wormhash *wh_dst, *wh_src;
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uint32_t dip = 0, sip = 0;
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wh_dst = ebt_among_wh_dst(info);
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wh_src = ebt_among_wh_src(info);
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if (wh_src) {
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smac = eth_hdr(skb)->h_source;
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if (get_ip_src(skb, &sip))
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return EBT_NOMATCH;
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if (!(info->bitmask & EBT_AMONG_SRC_NEG)) {
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/* we match only if it contains */
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if (!ebt_mac_wormhash_contains(wh_src, smac, sip))
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return EBT_NOMATCH;
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} else {
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/* we match only if it DOES NOT contain */
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if (ebt_mac_wormhash_contains(wh_src, smac, sip))
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return EBT_NOMATCH;
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}
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}
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if (wh_dst) {
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dmac = eth_hdr(skb)->h_dest;
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if (get_ip_dst(skb, &dip))
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return EBT_NOMATCH;
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if (!(info->bitmask & EBT_AMONG_DST_NEG)) {
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/* we match only if it contains */
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if (!ebt_mac_wormhash_contains(wh_dst, dmac, dip))
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return EBT_NOMATCH;
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} else {
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/* we match only if it DOES NOT contain */
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if (ebt_mac_wormhash_contains(wh_dst, dmac, dip))
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return EBT_NOMATCH;
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}
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}
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return EBT_MATCH;
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}
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static int ebt_among_check(const char *tablename, unsigned int hookmask,
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const struct ebt_entry *e, void *data,
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unsigned int datalen)
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{
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struct ebt_among_info *info = (struct ebt_among_info *) data;
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int expected_length = sizeof(struct ebt_among_info);
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const struct ebt_mac_wormhash *wh_dst, *wh_src;
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int err;
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wh_dst = ebt_among_wh_dst(info);
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wh_src = ebt_among_wh_src(info);
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expected_length += ebt_mac_wormhash_size(wh_dst);
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expected_length += ebt_mac_wormhash_size(wh_src);
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if (datalen != EBT_ALIGN(expected_length)) {
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printk(KERN_WARNING
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"ebtables: among: wrong size: %d"
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"against expected %d, rounded to %Zd\n",
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datalen, expected_length,
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EBT_ALIGN(expected_length));
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return -EINVAL;
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}
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if (wh_dst && (err = ebt_mac_wormhash_check_integrity(wh_dst))) {
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printk(KERN_WARNING
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"ebtables: among: dst integrity fail: %x\n", -err);
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return -EINVAL;
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}
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if (wh_src && (err = ebt_mac_wormhash_check_integrity(wh_src))) {
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printk(KERN_WARNING
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"ebtables: among: src integrity fail: %x\n", -err);
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return -EINVAL;
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}
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return 0;
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}
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static struct ebt_match filter_among = {
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.name = EBT_AMONG_MATCH,
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.match = ebt_filter_among,
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.check = ebt_among_check,
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.me = THIS_MODULE,
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};
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static int __init init(void)
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{
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return ebt_register_match(&filter_among);
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}
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static void __exit fini(void)
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{
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ebt_unregister_match(&filter_among);
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}
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module_init(init);
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module_exit(fini);
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MODULE_LICENSE("GPL");
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