2005-08-22 00:31:06 -06:00
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/*
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* IP6 tables REJECT target module
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* Linux INET6 implementation
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*
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* Copyright (C)2003 USAGI/WIDE Project
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*
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* Authors:
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* Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
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*
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* Based on net/ipv4/netfilter/ipt_REJECT.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/icmpv6.h>
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#include <linux/netdevice.h>
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#include <net/ipv6.h>
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#include <net/tcp.h>
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#include <net/icmp.h>
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#include <net/ip6_checksum.h>
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#include <net/ip6_fib.h>
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#include <net/ip6_route.h>
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#include <net/flow.h>
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2007-02-07 16:11:19 -07:00
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#include <linux/netfilter/x_tables.h>
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2005-08-22 00:31:06 -06:00
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter_ipv6/ip6t_REJECT.h>
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MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
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2008-01-15 00:42:28 -07:00
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MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6");
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2005-08-22 00:31:06 -06:00
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MODULE_LICENSE("GPL");
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/* Send RST reply */
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static void send_reset(struct sk_buff *oldskb)
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{
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struct sk_buff *nskb;
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struct tcphdr otcph, *tcph;
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unsigned int otcplen, hh_len;
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int tcphoff, needs_ack;
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2008-04-14 01:56:05 -06:00
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const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);
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struct ipv6hdr *ip6h;
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2005-08-22 00:31:06 -06:00
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struct dst_entry *dst = NULL;
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u8 proto;
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struct flowi fl;
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if ((!(ipv6_addr_type(&oip6h->saddr) & IPV6_ADDR_UNICAST)) ||
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(!(ipv6_addr_type(&oip6h->daddr) & IPV6_ADDR_UNICAST))) {
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2007-07-07 23:39:38 -06:00
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pr_debug("ip6t_REJECT: addr is not unicast.\n");
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2005-08-22 00:31:06 -06:00
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return;
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}
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proto = oip6h->nexthdr;
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tcphoff = ipv6_skip_exthdr(oldskb, ((u8*)(oip6h+1) - oldskb->data), &proto);
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if ((tcphoff < 0) || (tcphoff > oldskb->len)) {
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2007-07-07 23:39:38 -06:00
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pr_debug("ip6t_REJECT: Can't get TCP header.\n");
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2005-08-22 00:31:06 -06:00
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return;
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}
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otcplen = oldskb->len - tcphoff;
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/* IP header checks: fragment, too short. */
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2007-07-07 23:19:08 -06:00
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if (proto != IPPROTO_TCP || otcplen < sizeof(struct tcphdr)) {
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2007-07-07 23:39:38 -06:00
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pr_debug("ip6t_REJECT: proto(%d) != IPPROTO_TCP, "
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"or too short. otcplen = %d\n",
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proto, otcplen);
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2005-08-22 00:31:06 -06:00
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return;
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}
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if (skb_copy_bits(oldskb, tcphoff, &otcph, sizeof(struct tcphdr)))
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BUG();
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/* No RST for RST. */
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if (otcph.rst) {
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2007-07-07 23:39:38 -06:00
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pr_debug("ip6t_REJECT: RST is set\n");
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2005-08-22 00:31:06 -06:00
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return;
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}
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/* Check checksum. */
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if (csum_ipv6_magic(&oip6h->saddr, &oip6h->daddr, otcplen, IPPROTO_TCP,
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skb_checksum(oldskb, tcphoff, otcplen, 0))) {
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2007-07-07 23:39:38 -06:00
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pr_debug("ip6t_REJECT: TCP checksum is invalid\n");
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2005-08-22 00:31:06 -06:00
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return;
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}
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memset(&fl, 0, sizeof(fl));
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fl.proto = IPPROTO_TCP;
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ipv6_addr_copy(&fl.fl6_src, &oip6h->daddr);
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ipv6_addr_copy(&fl.fl6_dst, &oip6h->saddr);
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fl.fl_ip_sport = otcph.dest;
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fl.fl_ip_dport = otcph.source;
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2006-08-05 00:12:42 -06:00
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security_skb_classify_flow(oldskb, &fl);
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2008-03-05 11:48:10 -07:00
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dst = ip6_route_output(&init_net, NULL, &fl);
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2005-08-22 00:31:06 -06:00
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if (dst == NULL)
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return;
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2005-09-08 16:11:55 -06:00
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if (dst->error || xfrm_lookup(&dst, &fl, NULL, 0))
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2005-08-22 00:31:06 -06:00
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return;
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hh_len = (dst->dev->hard_header_len + 15)&~15;
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nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
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+ sizeof(struct tcphdr) + dst->trailer_len,
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GFP_ATOMIC);
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if (!nskb) {
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if (net_ratelimit())
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printk("ip6t_REJECT: Can't alloc skb\n");
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dst_release(dst);
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return;
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}
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nskb->dst = dst;
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skb_reserve(nskb, hh_len + dst->header_len);
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2007-03-10 15:57:15 -07:00
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skb_put(nskb, sizeof(struct ipv6hdr));
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skb_reset_network_header(nskb);
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2007-04-25 18:54:47 -06:00
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ip6h = ipv6_hdr(nskb);
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2005-08-22 00:31:06 -06:00
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ip6h->version = 6;
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ip6h->hop_limit = dst_metric(dst, RTAX_HOPLIMIT);
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ip6h->nexthdr = IPPROTO_TCP;
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ipv6_addr_copy(&ip6h->saddr, &oip6h->daddr);
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ipv6_addr_copy(&ip6h->daddr, &oip6h->saddr);
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tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
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/* Truncate to length (no data) */
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tcph->doff = sizeof(struct tcphdr)/4;
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tcph->source = otcph.dest;
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tcph->dest = otcph.source;
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if (otcph.ack) {
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needs_ack = 0;
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tcph->seq = otcph.ack_seq;
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tcph->ack_seq = 0;
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} else {
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needs_ack = 1;
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tcph->ack_seq = htonl(ntohl(otcph.seq) + otcph.syn + otcph.fin
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+ otcplen - (otcph.doff<<2));
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tcph->seq = 0;
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}
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/* Reset flags */
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((u_int8_t *)tcph)[13] = 0;
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tcph->rst = 1;
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tcph->ack = needs_ack;
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tcph->window = 0;
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tcph->urg_ptr = 0;
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tcph->check = 0;
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/* Adjust TCP checksum */
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2007-04-25 18:54:47 -06:00
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tcph->check = csum_ipv6_magic(&ipv6_hdr(nskb)->saddr,
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&ipv6_hdr(nskb)->daddr,
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2005-08-22 00:31:06 -06:00
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sizeof(struct tcphdr), IPPROTO_TCP,
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2007-07-07 23:16:55 -06:00
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csum_partial(tcph,
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2005-08-22 00:31:06 -06:00
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sizeof(struct tcphdr), 0));
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2006-02-15 16:23:28 -07:00
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nf_ct_attach(nskb, oldskb);
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2008-01-11 20:15:08 -07:00
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ip6_local_out(nskb);
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2005-08-22 00:31:06 -06:00
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}
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static inline void
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send_unreach(struct sk_buff *skb_in, unsigned char code, unsigned int hooknum)
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{
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2007-11-19 19:53:30 -07:00
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if (hooknum == NF_INET_LOCAL_OUT && skb_in->dev == NULL)
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2007-09-26 23:10:56 -06:00
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skb_in->dev = init_net.loopback_dev;
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2005-08-22 00:31:06 -06:00
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icmpv6_send(skb_in, ICMPV6_DEST_UNREACH, code, 0, NULL);
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}
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2007-12-05 00:24:03 -07:00
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static unsigned int
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reject_tg6(struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, unsigned int hooknum,
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const struct xt_target *target, const void *targinfo)
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2005-08-22 00:31:06 -06:00
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{
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const struct ip6t_reject_info *reject = targinfo;
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2008-03-05 21:47:47 -07:00
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pr_debug("%s: medium point\n", __func__);
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2005-08-22 00:31:06 -06:00
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/* WARNING: This code causes reentry within ip6tables.
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This means that the ip6tables jump stack is now crap. We
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must return an absolute verdict. --RR */
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2007-02-09 07:24:49 -07:00
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switch (reject->with) {
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case IP6T_ICMP6_NO_ROUTE:
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2007-10-15 01:53:15 -06:00
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send_unreach(skb, ICMPV6_NOROUTE, hooknum);
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2007-02-09 07:24:49 -07:00
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break;
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case IP6T_ICMP6_ADM_PROHIBITED:
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2007-10-15 01:53:15 -06:00
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send_unreach(skb, ICMPV6_ADM_PROHIBITED, hooknum);
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2007-02-09 07:24:49 -07:00
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break;
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case IP6T_ICMP6_NOT_NEIGHBOUR:
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2007-10-15 01:53:15 -06:00
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send_unreach(skb, ICMPV6_NOT_NEIGHBOUR, hooknum);
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2007-02-09 07:24:49 -07:00
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break;
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case IP6T_ICMP6_ADDR_UNREACH:
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2007-10-15 01:53:15 -06:00
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send_unreach(skb, ICMPV6_ADDR_UNREACH, hooknum);
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2007-02-09 07:24:49 -07:00
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break;
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case IP6T_ICMP6_PORT_UNREACH:
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2007-10-15 01:53:15 -06:00
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send_unreach(skb, ICMPV6_PORT_UNREACH, hooknum);
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2007-02-09 07:24:49 -07:00
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break;
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case IP6T_ICMP6_ECHOREPLY:
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2005-08-22 00:31:06 -06:00
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/* Do nothing */
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break;
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case IP6T_TCP_RESET:
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2007-10-15 01:53:15 -06:00
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send_reset(skb);
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2005-08-22 00:31:06 -06:00
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break;
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default:
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if (net_ratelimit())
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printk(KERN_WARNING "ip6t_REJECT: case %u not handled yet\n", reject->with);
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break;
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}
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return NF_DROP;
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}
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2007-12-05 00:24:03 -07:00
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static bool
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reject_tg6_check(const char *tablename, const void *entry,
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const struct xt_target *target, void *targinfo,
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unsigned int hook_mask)
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2005-08-22 00:31:06 -06:00
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{
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2007-02-09 07:24:49 -07:00
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const struct ip6t_reject_info *rejinfo = targinfo;
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[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables
This monster-patch tries to do the best job for unifying the data
structures and backend interfaces for the three evil clones ip_tables,
ip6_tables and arp_tables. In an ideal world we would never have
allowed this kind of copy+paste programming... but well, our world
isn't (yet?) ideal.
o introduce a new x_tables module
o {ip,arp,ip6}_tables depend on this x_tables module
o registration functions for tables, matches and targets are only
wrappers around x_tables provided functions
o all matches/targets that are used from ip_tables and ip6_tables
are now implemented as xt_FOOBAR.c files and provide module aliases
to ipt_FOOBAR and ip6t_FOOBAR
o header files for xt_matches are in include/linux/netfilter/,
include/linux/netfilter_{ipv4,ipv6} contains compatibility wrappers
around the xt_FOOBAR.h headers
Based on this patchset we're going to further unify the code,
gradually getting rid of all the layer 3 specific assumptions.
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-12 14:30:04 -07:00
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const struct ip6t_entry *e = entry;
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2005-08-22 00:31:06 -06:00
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if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
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printk("ip6t_REJECT: ECHOREPLY is not supported.\n");
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2007-07-07 23:16:26 -06:00
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return false;
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2005-08-22 00:31:06 -06:00
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} else if (rejinfo->with == IP6T_TCP_RESET) {
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/* Must specify that it's a TCP packet */
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if (e->ipv6.proto != IPPROTO_TCP
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2007-02-07 16:11:19 -07:00
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|| (e->ipv6.invflags & XT_INV_PROTO)) {
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2007-07-07 23:39:38 -06:00
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printk("ip6t_REJECT: TCP_RESET illegal for non-tcp\n");
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2007-07-07 23:16:26 -06:00
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return false;
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2005-08-22 00:31:06 -06:00
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}
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}
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2007-07-07 23:16:26 -06:00
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return true;
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2005-08-22 00:31:06 -06:00
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}
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2007-12-05 00:24:03 -07:00
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static struct xt_target reject_tg6_reg __read_mostly = {
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2005-08-22 00:31:06 -06:00
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.name = "REJECT",
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2007-02-07 16:11:19 -07:00
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.family = AF_INET6,
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2007-12-05 00:24:03 -07:00
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.target = reject_tg6,
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2006-03-20 19:01:43 -07:00
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.targetsize = sizeof(struct ip6t_reject_info),
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.table = "filter",
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2007-11-19 19:53:30 -07:00
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.hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
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(1 << NF_INET_LOCAL_OUT),
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2007-12-05 00:24:03 -07:00
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.checkentry = reject_tg6_check,
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2005-08-22 00:31:06 -06:00
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.me = THIS_MODULE
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};
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2007-12-05 00:24:03 -07:00
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static int __init reject_tg6_init(void)
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2005-08-22 00:31:06 -06:00
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{
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2007-12-05 00:24:03 -07:00
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return xt_register_target(&reject_tg6_reg);
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2005-08-22 00:31:06 -06:00
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}
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2007-12-05 00:24:03 -07:00
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static void __exit reject_tg6_exit(void)
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2005-08-22 00:31:06 -06:00
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{
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2007-12-05 00:24:03 -07:00
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xt_unregister_target(&reject_tg6_reg);
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2005-08-22 00:31:06 -06:00
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}
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2007-12-05 00:24:03 -07:00
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module_init(reject_tg6_init);
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module_exit(reject_tg6_exit);
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