* published by the Free Software Foundation.
*/
-#include <linux/config.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <net/tcp.h>
#include <net/route.h>
+#include <net/dst.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_REJECT.h>
#ifdef CONFIG_BRIDGE_NETFILTER
#define DEBUGP(format, args...)
#endif
-/* If the original packet is part of a connection, but the connection
- is not confirmed, our manufactured reply will not be associated
- with it, so we need to do this manually. */
-static void connection_attach(struct sk_buff *new_skb, struct sk_buff *skb)
-{
- void (*attach)(struct sk_buff *, struct sk_buff *);
-
- /* Avoid module unload race with ip_ct_attach being NULLed out */
- if (skb->nfct && (attach = ip_ct_attach) != NULL) {
- mb(); /* Just to be sure: must be read before executing this */
- attach(new_skb, skb);
- }
-}
-
-static inline struct rtable *route_reverse(struct sk_buff *skb, 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;
- }
-
- if (rt->u.dst.error) {
- dst_release(&rt->u.dst);
- rt = NULL;
- }
-
- return rt;
-}
-
/* 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;
+ __be16 tmp_port;
+ __be32 tmp_addr;
int needs_ack;
- int hh_len;
+ unsigned int addr_type;
/* IP header checks: fragment. */
if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
if (oth->rst)
return;
- /* FIXME: Check checksum --RR */
- if ((rt = route_reverse(oldskb, hook)) == NULL)
+ /* Check checksum */
+ if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
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),
+ nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
GFP_ATOMIC);
- if (!nskb) {
- dst_release(&rt->u.dst);
+ if (!nskb)
return;
- }
-
- dst_release(nskb->dst);
- nskb->dst = &rt->u.dst;
/* This packet will not be the same as the other: clear nf fields */
nf_reset(nskb);
- nskb->nfcache = 0;
- nskb->nfmark = 0;
-#ifdef CONFIG_BRIDGE_NETFILTER
- nf_bridge_put(nskb->nf_bridge);
- nskb->nf_bridge = NULL;
-#endif
+ nskb->mark = 0;
+ skb_init_secmark(nskb);
+
+ skb_shinfo(nskb)->gso_size = 0;
+ skb_shinfo(nskb)->gso_segs = 0;
+ skb_shinfo(nskb)->gso_type = 0;
tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);
csum_partial((char *)tcph,
sizeof(struct tcphdr), 0));
- /* Adjust IP TTL, DF */
- nskb->nh.iph->ttl = MAXTTL;
/* Set DF, id = 0 */
nskb->nh.iph->frag_off = htons(IP_DF);
nskb->nh.iph->id = 0;
+ addr_type = RTN_UNSPEC;
+ if (hook != NF_IP_FORWARD
+#ifdef CONFIG_BRIDGE_NETFILTER
+ || (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
+#endif
+ )
+ addr_type = RTN_LOCAL;
+
+ if (ip_route_me_harder(&nskb, addr_type))
+ goto free_nskb;
+
+ nskb->ip_summed = CHECKSUM_NONE;
+
+ /* Adjust IP TTL */
+ nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
+
/* 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_pmtu(nskb->dst))
+ if (nskb->len > dst_mtu(nskb->dst))
goto free_nskb;
- connection_attach(nskb, oldskb);
+ nf_ct_attach(nskb, oldskb);
NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
- ip_finish_output);
+ dst_output);
return;
free_nskb:
kfree_skb(nskb);
}
-static void send_unreach(struct sk_buff *skb_in, int code)
+static inline void send_unreach(struct sk_buff *skb_in, int code)
{
- struct iphdr *iph;
- struct udphdr *udph;
- struct icmphdr *icmph;
- struct sk_buff *nskb;
- u32 saddr;
- u8 tos;
- int hh_len, length;
- struct rtable *rt = (struct rtable*)skb_in->dst;
- unsigned char *data;
-
- if (!rt)
- return;
-
- /* FIXME: Use sysctl number. --RR */
- if (!xrlim_allow(&rt->u.dst, 1*HZ))
- return;
-
- iph = skb_in->nh.iph;
-
- /* No replies to physical multicast/broadcast */
- if (skb_in->pkt_type!=PACKET_HOST)
- return;
-
- /* Now check at the protocol level */
- if (rt->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST))
- return;
-
- /* Only reply to fragment 0. */
- if (iph->frag_off&htons(IP_OFFSET))
- return;
-
- /* Ensure we have at least 8 bytes of proto header. */
- if (skb_in->len < skb_in->nh.iph->ihl*4 + 8)
- return;
-
- /* if UDP checksum is set, verify it's correct */
- if (iph->protocol == IPPROTO_UDP
- && skb_in->tail-(u8*)iph >= sizeof(struct udphdr)) {
- int datalen = skb_in->len - (iph->ihl<<2);
- udph = (struct udphdr *)((char *)iph + (iph->ihl<<2));
- if (udph->check
- && csum_tcpudp_magic(iph->saddr, iph->daddr,
- datalen, IPPROTO_UDP,
- csum_partial((char *)udph, datalen,
- 0)) != 0)
- return;
- }
-
- /* If we send an ICMP error to an ICMP error a mess would result.. */
- if (iph->protocol == IPPROTO_ICMP
- && skb_in->tail-(u8*)iph >= sizeof(struct icmphdr)) {
- icmph = (struct icmphdr *)((char *)iph + (iph->ihl<<2));
-
- if (skb_copy_bits(skb_in, skb_in->nh.iph->ihl*4,
- icmph, sizeof(*icmph)) < 0)
- return;
-
- /* Between echo-reply (0) and timestamp (13),
- everything except echo-request (8) is an error.
- Also, anything greater than NR_ICMP_TYPES is
- unknown, and hence should be treated as an error... */
- if ((icmph->type < ICMP_TIMESTAMP
- && icmph->type != ICMP_ECHOREPLY
- && icmph->type != ICMP_ECHO)
- || icmph->type > NR_ICMP_TYPES)
- return;
- }
-
- saddr = iph->daddr;
- if (!(rt->rt_flags & RTCF_LOCAL))
- saddr = 0;
-
- tos = (iph->tos & IPTOS_TOS_MASK) | IPTOS_PREC_INTERNETCONTROL;
-
- {
- struct flowi fl = { .nl_u = { .ip4_u =
- { .daddr = skb_in->nh.iph->saddr,
- .saddr = saddr,
- .tos = RT_TOS(tos) } } };
- if (ip_route_output_key(&rt, &fl))
- return;
- }
- /* RFC says return as much as we can without exceeding 576 bytes. */
- length = skb_in->len + sizeof(struct iphdr) + sizeof(struct icmphdr);
-
- if (length > dst_pmtu(&rt->u.dst))
- length = dst_pmtu(&rt->u.dst);
- if (length > 576)
- length = 576;
-
- hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
-
- nskb = alloc_skb(hh_len + length, GFP_ATOMIC);
- if (!nskb) {
- ip_rt_put(rt);
- return;
- }
-
- nskb->priority = 0;
- nskb->dst = &rt->u.dst;
- skb_reserve(nskb, hh_len);
-
- /* Set up IP header */
- iph = nskb->nh.iph
- = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
- iph->version=4;
- iph->ihl=5;
- iph->tos=tos;
- iph->tot_len = htons(length);
-
- /* PMTU discovery never applies to ICMP packets. */
- iph->frag_off = 0;
-
- iph->ttl = MAXTTL;
- ip_select_ident(iph, &rt->u.dst, NULL);
- iph->protocol=IPPROTO_ICMP;
- iph->saddr=rt->rt_src;
- iph->daddr=rt->rt_dst;
- iph->check=0;
- iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
-
- /* Set up ICMP header. */
- icmph = nskb->h.icmph
- = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
- icmph->type = ICMP_DEST_UNREACH;
- icmph->code = code;
- icmph->un.gateway = 0;
- icmph->checksum = 0;
-
- /* Copy as much of original packet as will fit */
- data = skb_put(nskb,
- length - sizeof(struct iphdr) - sizeof(struct icmphdr));
-
- skb_copy_bits(skb_in, 0, data,
- length - sizeof(struct iphdr) - sizeof(struct icmphdr));
-
- icmph->checksum = ip_compute_csum((unsigned char *)icmph,
- length - sizeof(struct iphdr));
-
- connection_attach(nskb, skb_in);
-
- NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
- ip_finish_output);
+ 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 void *targinfo,
- void *userinfo)
+ const struct xt_target *target,
+ const void *targinfo)
{
const struct ipt_reject_info *reject = targinfo;
}
static int check(const char *tablename,
- const struct ipt_entry *e,
+ const void *e_void,
+ const struct xt_target *target,
void *targinfo,
- unsigned int targinfosize,
unsigned int hook_mask)
{
const struct ipt_reject_info *rejinfo = targinfo;
-
- if (targinfosize != IPT_ALIGN(sizeof(struct ipt_reject_info))) {
- DEBUGP("REJECT: targinfosize %u != 0\n", targinfosize);
- return 0;
- }
-
- /* Only allow these for packet filtering. */
- if (strcmp(tablename, "filter") != 0) {
- DEBUGP("REJECT: bad table `%s'.\n", tablename);
- return 0;
- }
- if ((hook_mask & ~((1 << NF_IP_LOCAL_IN)
- | (1 << NF_IP_FORWARD)
- | (1 << NF_IP_LOCAL_OUT))) != 0) {
- DEBUGP("REJECT: bad hook mask %X\n", hook_mask);
- return 0;
- }
+ const struct ipt_entry *e = e_void;
if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
printk("REJECT: ECHOREPLY no longer supported.\n");
return 0;
}
}
-
return 1;
}
static struct ipt_target ipt_reject_reg = {
.name = "REJECT",
.target = reject,
+ .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,
.me = THIS_MODULE,
};
-static int __init init(void)
+static int __init ipt_reject_init(void)
{
return ipt_register_target(&ipt_reject_reg);
}
-static void __exit fini(void)
+static void __exit ipt_reject_fini(void)
{
ipt_unregister_target(&ipt_reject_reg);
}
-module_init(init);
-module_exit(fini);
+module_init(ipt_reject_init);
+module_exit(ipt_reject_fini);