/*
* This is a module which is used for rejecting packets.
- * Added support for customized reject packets (Jozsef Kadlecsik).
- * Added support for ICMP type-3-code-13 (Maciej Soltysiak). [RFC 1812]
*/
/* (C) 1999-2001 Paul `Rusty' Russell
#include <net/tcp.h>
#include <net/route.h>
#include <net/dst.h>
+#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_REJECT.h>
#ifdef CONFIG_BRIDGE_NETFILTER
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
-MODULE_DESCRIPTION("iptables REJECT target module");
-
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
-
-static inline struct rtable *route_reverse(struct sk_buff *skb,
- struct tcphdr *tcph, int hook)
-{
- struct iphdr *iph = skb->nh.iph;
- struct dst_entry *odst;
- struct flowi fl = {};
- struct rtable *rt;
-
- /* We don't require ip forwarding to be enabled to be able to
- * send a RST reply for bridged traffic. */
- if (hook != NF_IP_FORWARD
-#ifdef CONFIG_BRIDGE_NETFILTER
- || (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
-#endif
- ) {
- fl.nl_u.ip4_u.daddr = iph->saddr;
- if (hook == NF_IP_LOCAL_IN)
- fl.nl_u.ip4_u.saddr = iph->daddr;
- fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
-
- if (ip_route_output_key(&rt, &fl) != 0)
- return NULL;
- } else {
- /* non-local src, find valid iif to satisfy
- * rp-filter when calling ip_route_input. */
- fl.nl_u.ip4_u.daddr = iph->daddr;
- if (ip_route_output_key(&rt, &fl) != 0)
- return NULL;
-
- odst = skb->dst;
- if (ip_route_input(skb, iph->saddr, iph->daddr,
- RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
- dst_release(&rt->u.dst);
- return NULL;
- }
- dst_release(&rt->u.dst);
- rt = (struct rtable *)skb->dst;
- skb->dst = odst;
-
- fl.nl_u.ip4_u.daddr = iph->saddr;
- fl.nl_u.ip4_u.saddr = iph->daddr;
- fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
- }
-
- if (rt->u.dst.error) {
- dst_release(&rt->u.dst);
- return NULL;
- }
-
- fl.proto = IPPROTO_TCP;
- fl.fl_ip_sport = tcph->dest;
- fl.fl_ip_dport = tcph->source;
- security_skb_classify_flow(skb, &fl);
-
- xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
-
- return rt;
-}
+MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4");
/* Send RST reply */
static void send_reset(struct sk_buff *oldskb, int hook)
{
struct sk_buff *nskb;
- struct iphdr *iph = oldskb->nh.iph;
- struct tcphdr _otcph, *oth, *tcph;
- struct rtable *rt;
- u_int16_t tmp_port;
- u_int32_t tmp_addr;
- int needs_ack;
- int hh_len;
+ const struct iphdr *oiph;
+ struct iphdr *niph;
+ const struct tcphdr *oth;
+ struct tcphdr _otcph, *tcph;
+ unsigned int addr_type;
/* IP header checks: fragment. */
- if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
+ if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
return;
- oth = skb_header_pointer(oldskb, oldskb->nh.iph->ihl * 4,
+ oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
sizeof(_otcph), &_otcph);
if (oth == NULL)
- return;
+ return;
/* No RST for RST. */
if (oth->rst)
return;
/* Check checksum */
- if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
+ if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
return;
+ oiph = ip_hdr(oldskb);
- if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
+ nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
+ LL_MAX_HEADER, GFP_ATOMIC);
+ if (!nskb)
return;
- hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
-
- /* We need a linear, writeable skb. We also need to expand
- headroom in case hh_len of incoming interface < hh_len of
- outgoing interface */
- nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
- GFP_ATOMIC);
- if (!nskb) {
- dst_release(&rt->u.dst);
- return;
+ skb_reserve(nskb, LL_MAX_HEADER);
+
+ skb_reset_network_header(nskb);
+ niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
+ niph->version = 4;
+ niph->ihl = sizeof(struct iphdr) / 4;
+ niph->tos = 0;
+ niph->id = 0;
+ niph->frag_off = htons(IP_DF);
+ niph->protocol = IPPROTO_TCP;
+ niph->check = 0;
+ niph->saddr = oiph->daddr;
+ niph->daddr = oiph->saddr;
+
+ tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
+ memset(tcph, 0, sizeof(*tcph));
+ tcph->source = oth->dest;
+ tcph->dest = oth->source;
+ tcph->doff = sizeof(struct tcphdr) / 4;
+
+ if (oth->ack)
+ tcph->seq = oth->ack_seq;
+ else {
+ tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
+ oldskb->len - ip_hdrlen(oldskb) -
+ (oth->doff << 2));
+ tcph->ack = 1;
}
- dst_release(nskb->dst);
- nskb->dst = &rt->u.dst;
+ tcph->rst = 1;
+ tcph->check = tcp_v4_check(sizeof(struct tcphdr),
+ niph->saddr, niph->daddr,
+ csum_partial(tcph,
+ sizeof(struct tcphdr), 0));
- /* This packet will not be the same as the other: clear nf fields */
- nf_reset(nskb);
- nskb->nfmark = 0;
- skb_init_secmark(nskb);
-
- tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);
-
- /* Swap source and dest */
- tmp_addr = nskb->nh.iph->saddr;
- nskb->nh.iph->saddr = nskb->nh.iph->daddr;
- nskb->nh.iph->daddr = tmp_addr;
- tmp_port = tcph->source;
- tcph->source = tcph->dest;
- tcph->dest = tmp_port;
-
- /* Truncate to length (no data) */
- tcph->doff = sizeof(struct tcphdr)/4;
- skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
- nskb->nh.iph->tot_len = htons(nskb->len);
-
- if (tcph->ack) {
- needs_ack = 0;
- tcph->seq = oth->ack_seq;
- tcph->ack_seq = 0;
- } else {
- needs_ack = 1;
- tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin
- + oldskb->len - oldskb->nh.iph->ihl*4
- - (oth->doff<<2));
- tcph->seq = 0;
- }
+ addr_type = RTN_UNSPEC;
+ if (hook != NF_INET_FORWARD
+#ifdef CONFIG_BRIDGE_NETFILTER
+ || (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
+#endif
+ )
+ addr_type = RTN_LOCAL;
- /* Reset flags */
- ((u_int8_t *)tcph)[13] = 0;
- tcph->rst = 1;
- tcph->ack = needs_ack;
+ /* ip_route_me_harder expects skb->dst to be set */
+ skb_dst_set(nskb, dst_clone(skb_dst(oldskb)));
- tcph->window = 0;
- tcph->urg_ptr = 0;
+ if (ip_route_me_harder(nskb, addr_type))
+ goto free_nskb;
- /* Adjust TCP checksum */
+ niph->ttl = dst_metric(skb_dst(nskb), RTAX_HOPLIMIT);
nskb->ip_summed = CHECKSUM_NONE;
- tcph->check = 0;
- tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
- nskb->nh.iph->saddr,
- nskb->nh.iph->daddr,
- csum_partial((char *)tcph,
- sizeof(struct tcphdr), 0));
-
- /* Adjust IP TTL, DF */
- nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
- /* Set DF, id = 0 */
- nskb->nh.iph->frag_off = htons(IP_DF);
- nskb->nh.iph->id = 0;
-
- /* Adjust IP checksum */
- nskb->nh.iph->check = 0;
- nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph,
- nskb->nh.iph->ihl);
/* "Never happens" */
- if (nskb->len > dst_mtu(nskb->dst))
+ if (nskb->len > dst_mtu(skb_dst(nskb)))
goto free_nskb;
nf_ct_attach(nskb, oldskb);
- NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
- dst_output);
+ ip_local_out(nskb);
return;
free_nskb:
static inline void send_unreach(struct sk_buff *skb_in, int code)
{
icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0);
-}
-
-static unsigned int reject(struct sk_buff **pskb,
- const struct net_device *in,
- const struct net_device *out,
- unsigned int hooknum,
- const struct xt_target *target,
- const void *targinfo,
- void *userinfo)
-{
- const struct ipt_reject_info *reject = targinfo;
+}
- /* Our naive response construction doesn't deal with IP
- options, and probably shouldn't try. */
- if ((*pskb)->nh.iph->ihl<<2 != sizeof(struct iphdr))
- return NF_DROP;
+static unsigned int
+reject_tg(struct sk_buff *skb, const struct xt_target_param *par)
+{
+ const struct ipt_reject_info *reject = par->targinfo;
/* WARNING: This code causes reentry within iptables.
This means that the iptables jump stack is now crap. We
must return an absolute verdict. --RR */
- switch (reject->with) {
- case IPT_ICMP_NET_UNREACHABLE:
- send_unreach(*pskb, ICMP_NET_UNREACH);
- break;
- case IPT_ICMP_HOST_UNREACHABLE:
- send_unreach(*pskb, ICMP_HOST_UNREACH);
- break;
- case IPT_ICMP_PROT_UNREACHABLE:
- send_unreach(*pskb, ICMP_PROT_UNREACH);
- break;
- case IPT_ICMP_PORT_UNREACHABLE:
- send_unreach(*pskb, ICMP_PORT_UNREACH);
- break;
- case IPT_ICMP_NET_PROHIBITED:
- send_unreach(*pskb, ICMP_NET_ANO);
- break;
+ switch (reject->with) {
+ case IPT_ICMP_NET_UNREACHABLE:
+ send_unreach(skb, ICMP_NET_UNREACH);
+ break;
+ case IPT_ICMP_HOST_UNREACHABLE:
+ send_unreach(skb, ICMP_HOST_UNREACH);
+ break;
+ case IPT_ICMP_PROT_UNREACHABLE:
+ send_unreach(skb, ICMP_PROT_UNREACH);
+ break;
+ case IPT_ICMP_PORT_UNREACHABLE:
+ send_unreach(skb, ICMP_PORT_UNREACH);
+ break;
+ case IPT_ICMP_NET_PROHIBITED:
+ send_unreach(skb, ICMP_NET_ANO);
+ break;
case IPT_ICMP_HOST_PROHIBITED:
- send_unreach(*pskb, ICMP_HOST_ANO);
- break;
- case IPT_ICMP_ADMIN_PROHIBITED:
- send_unreach(*pskb, ICMP_PKT_FILTERED);
+ send_unreach(skb, ICMP_HOST_ANO);
+ break;
+ case IPT_ICMP_ADMIN_PROHIBITED:
+ send_unreach(skb, ICMP_PKT_FILTERED);
break;
case IPT_TCP_RESET:
- send_reset(*pskb, hooknum);
+ send_reset(skb, par->hooknum);
case IPT_ICMP_ECHOREPLY:
/* Doesn't happen. */
break;
return NF_DROP;
}
-static int check(const char *tablename,
- const void *e_void,
- const struct xt_target *target,
- void *targinfo,
- unsigned int targinfosize,
- unsigned int hook_mask)
+static bool reject_tg_check(const struct xt_tgchk_param *par)
{
- const struct ipt_reject_info *rejinfo = targinfo;
- const struct ipt_entry *e = e_void;
+ const struct ipt_reject_info *rejinfo = par->targinfo;
+ const struct ipt_entry *e = par->entryinfo;
if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
- printk("REJECT: ECHOREPLY no longer supported.\n");
- return 0;
+ printk("ipt_REJECT: ECHOREPLY no longer supported.\n");
+ return false;
} else if (rejinfo->with == IPT_TCP_RESET) {
/* Must specify that it's a TCP packet */
- if (e->ip.proto != IPPROTO_TCP
- || (e->ip.invflags & IPT_INV_PROTO)) {
- DEBUGP("REJECT: TCP_RESET invalid for non-tcp\n");
- return 0;
+ if (e->ip.proto != IPPROTO_TCP ||
+ (e->ip.invflags & XT_INV_PROTO)) {
+ printk("ipt_REJECT: TCP_RESET invalid for non-tcp\n");
+ return false;
}
}
- return 1;
+ return true;
}
-static struct ipt_target ipt_reject_reg = {
+static struct xt_target reject_tg_reg __read_mostly = {
.name = "REJECT",
- .target = reject,
+ .family = NFPROTO_IPV4,
+ .target = reject_tg,
.targetsize = sizeof(struct ipt_reject_info),
.table = "filter",
- .hooks = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
- (1 << NF_IP_LOCAL_OUT),
- .checkentry = check,
+ .hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
+ (1 << NF_INET_LOCAL_OUT),
+ .checkentry = reject_tg_check,
.me = THIS_MODULE,
};
-static int __init ipt_reject_init(void)
+static int __init reject_tg_init(void)
{
- return ipt_register_target(&ipt_reject_reg);
+ return xt_register_target(&reject_tg_reg);
}
-static void __exit ipt_reject_fini(void)
+static void __exit reject_tg_exit(void)
{
- ipt_unregister_target(&ipt_reject_reg);
+ xt_unregister_target(&reject_tg_reg);
}
-module_init(ipt_reject_init);
-module_exit(ipt_reject_fini);
+module_init(reject_tg_init);
+module_exit(reject_tg_exit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff