static unsigned int ipt_mirror_target(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo,
void *userinfo)
{
if (((*pskb)->dst != NULL) &&
route_mirror(*pskb)) {
ip_rewrite(*pskb);
/* If we are not at FORWARD hook (INPUT/PREROUTING),
* the TTL isn't decreased by the IP stack */
if (hooknum != NF_IP_FORWARD) {
struct iphdr *iph = (*pskb)->nh.iph;
if (iph->ttl <= 1) {
/* this will traverse normal stack, and
* thus call conntrack on the icmp packet */
icmp_send(*pskb, ICMP_TIME_EXCEEDED,
ICMP_EXC_TTL, 0);
return NF_DROP;
}
ip_decrease_ttl(iph);
}
/* Don't let conntrack code see this packet:
it will think we are starting a new
connection! --RR */
ip_direct_send(*pskb);
return NF_STOLEN;
}
return NF_DROP;
}
static unsigned int
route6_oif(const struct ip6t_route_target_info *route_info,
struct sk_buff *skb)
{
unsigned int ifindex = 0;
struct net_device *dev_out = NULL;
/* The user set the interface name to use.
* Getting the current interface index.
*/
if ((dev_out = dev_get_by_name(route_info->oif))) {
ifindex = dev_out->ifindex;
} else {
/* Unknown interface name : packet dropped */
if (net_ratelimit())
DEBUGP("ip6t_ROUTE: oif interface %s not found\n", route_info->oif);
if (route_info->flags & IP6T_ROUTE_CONTINUE)
return IP6T_CONTINUE;
else
return NF_DROP;
}
/* Trying the standard way of routing packets */
if (route6(skb, ifindex, route_info)) {
dev_put(dev_out);
if (route_info->flags & IP6T_ROUTE_CONTINUE)
return IP6T_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
} else
return NF_DROP;
}
static unsigned int route_gw(const struct ipt_route_target_info *route_info,
struct sk_buff *skb)
{
if (route(skb, 0, route_info)!=1)
return NF_DROP;
if (route_info->flags & IPT_ROUTE_CONTINUE)
return IPT_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
}
static unsigned int ipt_mirror_target(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo,
void *userinfo)
{
struct rtable *rt;
struct sk_buff *nskb;
unsigned int hh_len;
/* If we are not at FORWARD hook (INPUT/PREROUTING),
* the TTL isn't decreased by the IP stack */
if (hooknum != NF_IP_FORWARD) {
struct iphdr *iph = (*pskb)->nh.iph;
if (iph->ttl <= 1) {
/* this will traverse normal stack, and
* thus call conntrack on the icmp packet */
icmp_send(*pskb, ICMP_TIME_EXCEEDED,
ICMP_EXC_TTL, 0);
return NF_DROP;
}
ip_decrease_ttl(iph);
}
if ((rt = route_mirror(*pskb, hooknum == NF_IP_LOCAL_IN)) == NULL)
return NF_DROP;
hh_len = (rt->u.dst.dev->hard_header_len + 15) & ~15;
/* Copy skb (even if skb is about to be dropped, we can't just
* clone it because there may be other things, such as tcpdump,
* interested in it). We also need to expand headroom in case
* hh_len of incoming interface < hh_len of outgoing interface */
nskb = skb_copy_expand(*pskb, hh_len, skb_tailroom(*pskb), GFP_ATOMIC);
if (nskb == NULL) {
dst_release(&rt->u.dst);
return NF_DROP;
}
dst_release(nskb->dst);
nskb->dst = &rt->u.dst;
ip_rewrite(nskb);
/* Don't let conntrack code see this packet:
it will think we are starting a new
connection! --RR */
ip_direct_send(nskb);
return NF_DROP;
}
static unsigned int
route6_oif(const struct ip6t_route_target_info *route_info,
struct sk_buff *skb)
{
unsigned int ifindex = 0;
struct net_device *dev_out = NULL;
/* The user set the interface name to use.
* Getting the current interface index.
*/
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
if ((dev_out = dev_get_by_name(&init_net, route_info->oif))) {
#else
if ((dev_out = dev_get_by_name(route_info->oif))) {
#endif
ifindex = dev_out->ifindex;
} else {
/* Unknown interface name : packet dropped */
if (net_ratelimit())
DEBUGP("ip6t_ROUTE: oif interface %s not found\n", route_info->oif);
if (route_info->flags & IP6T_ROUTE_CONTINUE)
return IP6T_CONTINUE;
else
return NF_DROP;
}
/* Trying the standard way of routing packets */
if (route6(skb, ifindex, route_info)) {
dev_put(dev_out);
if (route_info->flags & IP6T_ROUTE_CONTINUE)
return IP6T_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
} else
return NF_DROP;
}
static unsigned int
route6_gw(const struct ip6t_route_target_info *route_info,
struct sk_buff *skb)
{
if (route6(skb, 0, route_info)) {
if (route_info->flags & IP6T_ROUTE_CONTINUE)
return IP6T_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
} else
return NF_DROP;
}
static unsigned int
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
target(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo,
void *userinfo)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
target(struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const void *targinfo,
void *userinfo)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
target(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)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
target(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)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
target(struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const struct xt_target *target,
const void *targinfo)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36)
target(struct sk_buff *skb,
const struct xt_target_param *par)
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36) */
target(struct sk_buff *skb,
const struct xt_action_param *par)
#endif
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
const struct ip6t_route_target_info *route_info = targinfo;
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36)
const struct ip6t_route_target_info *route_info = par->targinfo;
unsigned int hooknum = par->hooknum;
#else
const struct ip6t_route_target_info *route_info = par->targinfo;
unsigned int hooknum = par->hooknum;
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
struct sk_buff *skb = *pskb;
#endif
struct in6_addr *gw = (struct in6_addr*)&route_info->gw;
unsigned int res;
if (route_info->flags & IP6T_ROUTE_CONTINUE)
goto do_it;
/* If we are at PREROUTING or INPUT hook
* the TTL isn't decreased by the IP stack
*/
if (hooknum == NF_INET_PRE_ROUTING ||
hooknum == NF_INET_LOCAL_IN) {
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
if (ipv6h->hop_limit <= 1) {
/* Force OUTPUT device used as source address */
skb->dev = skb_dst(skb)->dev;
icmpv6_send(skb, ICMPV6_TIME_EXCEED,
ICMPV6_EXC_HOPLIMIT, 0);
return NF_DROP;
}
ipv6h->hop_limit--;
}
if ((route_info->flags & IP6T_ROUTE_TEE)) {
/*
* Copy the skb, and route the copy. Will later return
* IP6T_CONTINUE for the original skb, which should continue
* on its way as if nothing happened. The copy should be
* independantly delivered to the ROUTE --gw.
*/
skb = skb_copy(skb, GFP_ATOMIC);
if (!skb) {
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ip6t_ROUTE: copy failed!\n");
return IP6T_CONTINUE;
}
}
do_it:
if (route_info->oif[0]) {
res = route6_oif(route_info, skb);
} else if (!ipv6_addr_any(gw)) {
res = route6_gw(route_info, skb);
} else {
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ip6t_ROUTE: no parameter !\n");
res = IP6T_CONTINUE;
}
if ((route_info->flags & IP6T_ROUTE_TEE))
res = IP6T_CONTINUE;
return res;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
static int
checkentry(const char *tablename,
const struct ip6t_entry *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
static int
checkentry(const char *tablename,
const void *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
static int
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
static int
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
static bool
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28) */
static bool
checkentry(const struct xt_tgchk_param *par)
#endif
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
const char *tablename = par->table;
#endif
if (strcmp(tablename, "mangle") != 0) {
printk("ip6t_ROUTE: can only be called from \"mangle\" table.\n");
return 0;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_route_target_info))) {
printk(KERN_WARNING "ip6t_ROUTE: targinfosize %u != %Zu\n",
targinfosize,
IP6T_ALIGN(sizeof(struct ip6t_route_target_info)));
return 0;
}
#endif
return 1;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
static struct xt_target ip6t_route_reg = {
#else
static struct ip6t_target ip6t_route_reg = {
#endif
.name = "ROUTE",
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
.family = AF_INET6,
#endif
.target = target,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
.targetsize = sizeof(struct ip6t_route_target_info),
#endif
.checkentry = checkentry,
.me = THIS_MODULE
};
static int __init init(void)
{
printk(KERN_DEBUG "registering ipv6 ROUTE target\n");
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
if (xt_register_target(&ip6t_route_reg))
#else
if (ip6t_register_target(&ip6t_route_reg))
#endif
return -EINVAL;
return 0;
}
static void __exit fini(void)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
xt_unregister_target(&ip6t_route_reg);
#else
ip6t_unregister_target(&ip6t_route_reg);
#endif
}
module_init(init);
module_exit(fini);
MODULE_LICENSE("GPL");
static unsigned int route_oif(const struct ipt_route_target_info *route_info,
struct sk_buff *skb)
{
unsigned int ifindex = 0;
struct net_device *dev_out = NULL;
/* The user set the interface name to use.
* Getting the current interface index.
*/
if ((dev_out = dev_get_by_name(route_info->oif))) {
ifindex = dev_out->ifindex;
} else {
/* Unknown interface name : packet dropped */
if (net_ratelimit())
DEBUGP("ipt_ROUTE: oif interface %s not found\n", route_info->oif);
return NF_DROP;
}
/* Trying the standard way of routing packets */
switch (route(skb, ifindex, route_info)) {
case 1:
dev_put(dev_out);
if (route_info->flags & IPT_ROUTE_CONTINUE)
return IPT_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
case 0:
/* Failed to send to oif. Trying the hard way */
if (route_info->flags & IPT_ROUTE_CONTINUE)
return NF_DROP;
if (net_ratelimit())
DEBUGP("ipt_ROUTE: forcing the use of %i\n",
ifindex);
/* We have to force the use of an interface.
* This interface must be a tunnel interface since
* otherwise we can't guess the hw address for
* the packet. For a tunnel interface, no hw address
* is needed.
*/
if ((dev_out->type != ARPHRD_TUNNEL)
&& (dev_out->type != ARPHRD_IPGRE)) {
if (net_ratelimit())
DEBUGP("ipt_ROUTE: can't guess the hw addr !\n");
dev_put(dev_out);
return NF_DROP;
}
/* Send the packet. This will also free skb
* Do not go through the POST_ROUTING hook because
* skb->dst is not set and because it will probably
* get confused by the destination IP address.
*/
skb->dev = dev_out;
dev_direct_send(skb);
dev_put(dev_out);
return NF_STOLEN;
default:
/* Unexpected error */
dev_put(dev_out);
return NF_DROP;
}
}
/* Send reply */
static void tarpit_tcp(struct sk_buff *oskb,struct rtable *ort,int local)
{
struct sk_buff *nskb;
struct rtable *nrt;
struct tcphdr *otcph, *ntcph;
struct flowi fl = {};
unsigned int otcplen;
u_int16_t tmp;
/* A truncated TCP header isn't going to be useful */
if (oskb->len < (ip_hdr(oskb)->ihl*4) + sizeof(struct tcphdr))
return;
otcph = (struct tcphdr *)((u_int32_t*)ip_hdr(oskb)
+ ip_hdr(oskb)->ihl);
otcplen = oskb->len - ip_hdr(oskb)->ihl*4;
/* No replies for RST or FIN */
if (otcph->rst || otcph->fin)
return;
/* No reply to !SYN,!ACK. Rate-limit replies to !SYN,ACKs */
if (!otcph->syn && (!otcph->ack || !xrlim_allow(&ort->u.dst, 1*HZ)))
return;
/* Check checksum. */
if (tcp_v4_check(otcplen, ip_hdr(oskb)->saddr,
ip_hdr(oskb)->daddr,
csum_partial((char *)otcph, otcplen, 0)) != 0)
return;
/* Copy skb (even if skb is about to be dropped, we can't just
clone it because there may be other things, such as tcpdump,
interested in it) */
nskb = skb_copy(oskb, GFP_ATOMIC);
if (!nskb)
return;
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
/* This packet will not be the same as the other: clear nf fields */
nf_conntrack_put(nskb->nfct);
nskb->nfct = NULL;
#endif /* CONFIG_NF_CONNTRACK */
ntcph = (struct tcphdr *)((u_int32_t*)ip_hdr(nskb) + ip_hdr(nskb)->ihl);
/* Truncate to length (no data) */
ntcph->doff = sizeof(struct tcphdr)/4;
skb_trim(nskb, ip_hdr(nskb)->ihl*4 + sizeof(struct tcphdr));
ip_hdr(nskb)->tot_len = htons(nskb->len);
/* Swap source and dest */
ip_hdr(nskb)->daddr = xchg(&ip_hdr(nskb)->saddr, ip_hdr(nskb)->daddr);
tmp = ntcph->source;
ntcph->source = ntcph->dest;
ntcph->dest = tmp;
/* Use supplied sequence number or make a new one */
ntcph->seq = otcph->ack ? otcph->ack_seq
: htonl(secure_tcp_sequence_number(ip_hdr(nskb)->saddr,
ip_hdr(nskb)->daddr,
ntcph->source,
ntcph->dest));
/* Our SYN-ACKs must have a >0 window */
ntcph->window = (otcph->syn && !otcph->ack) ? htons(5) : 0;
ntcph->urg_ptr = 0;
/* Reset flags */
((u_int8_t *)ntcph)[13] = 0;
if (otcph->syn && otcph->ack) {
ntcph->rst = 1;
ntcph->ack_seq = 0;
} else {
ntcph->syn = otcph->syn;
ntcph->ack = 1;
ntcph->ack_seq = htonl(ntohl(otcph->seq) + otcph->syn);
}
/* Adjust TCP checksum */
ntcph->check = 0;
ntcph->check = tcp_v4_check(sizeof(struct tcphdr),
ip_hdr(nskb)->saddr,
ip_hdr(nskb)->daddr,
csum_partial((char *)ntcph,
sizeof(struct tcphdr), 0));
fl.nl_u.ip4_u.daddr = ip_hdr(nskb)->daddr;
fl.nl_u.ip4_u.saddr = local ? ip_hdr(nskb)->saddr : 0;
fl.nl_u.ip4_u.tos = RT_TOS(ip_hdr(nskb)->tos) | RTO_CONN;
fl.oif = 0;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
if (ip_route_output_key(&init_net, &nrt, &fl))
#else
if (ip_route_output_key(&nrt, &fl))
#endif
goto free_nskb;
dst_release(nskb->dst);
nskb->dst = &nrt->u.dst;
/* Adjust IP TTL */
ip_hdr(nskb)->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
/* Set DF, id = 0 */
ip_hdr(nskb)->frag_off = htons(IP_DF);
ip_hdr(nskb)->id = 0;
/* Adjust IP checksum */
ip_hdr(nskb)->check = 0;
ip_hdr(nskb)->check = ip_fast_csum((unsigned char *)ip_hdr(nskb),
ip_hdr(nskb)->ihl);
/* "Never happens" */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
if (nskb->len > dst_mtu(nskb->dst))
#else
if (nskb->len > dst_pmtu(nskb->dst))
#endif
goto free_nskb;
ip_direct_send (nskb);
return;
free_nskb:
kfree_skb(nskb);
}
/* Try to route the packet according to the routing keys specified in
* route_info. Keys are :
* - ifindex :
* 0 if no oif preferred,
* otherwise set to the index of the desired oif
* - route_info->gw :
* 0 if no gateway specified,
* otherwise set to the next host to which the pkt must be routed
* If success, skb->dev is the output device to which the packet must
* be sent and skb->dst is not NULL
*
* RETURN: -1 if an error occured
* 1 if the packet was succesfully routed to the
* destination desired
* 0 if the kernel routing table could not route the packet
* according to the keys specified
*/
static int route(struct sk_buff *skb,
unsigned int ifindex,
const struct ipt_route_target_info *route_info)
{
int err;
struct rtable *rt;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
struct iphdr *iph = ip_hdr(skb);
#else
struct iphdr *iph = skb->nh.iph;
#endif
struct flowi fl = {
.oif = ifindex,
.nl_u = {
.ip4_u = {
.daddr = iph->daddr,
.saddr = 0,
.tos = RT_TOS(iph->tos),
.scope = RT_SCOPE_UNIVERSE,
}
}
};
/* The destination address may be overloaded by the target */
if (route_info->gw)
fl.fl4_dst = route_info->gw;
/* Trying to route the packet using the standard routing table. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
if ((err = ip_route_output_key(&init_net, &rt, &fl))) {
#else
if ((err = ip_route_output_key(&rt, &fl))) {
#endif
if (net_ratelimit())
DEBUGP("ipt_ROUTE: couldn't route pkt (err: %i)",err);
return -1;
}
/* Drop old route. */
dst_release(skb->dst);
skb->dst = NULL;
/* Success if no oif specified or if the oif correspond to the
* one desired */
if (!ifindex || rt->u.dst.dev->ifindex == ifindex) {
skb->dst = &rt->u.dst;
skb->dev = skb->dst->dev;
skb->protocol = htons(ETH_P_IP);
return 1;
}
/* The interface selected by the routing table is not the one
* specified by the user. This may happen because the dst address
* is one of our own addresses.
*/
if (net_ratelimit())
DEBUGP("ipt_ROUTE: failed to route as desired gw=%u.%u.%u.%u oif=%i (got oif=%i)\n",
NIPQUAD(route_info->gw), ifindex, rt->u.dst.dev->ifindex);
return 0;
}
/* Stolen from ip_finish_output2
* PRE : skb->dev is set to the device we are leaving by
* skb->dst is not NULL
* POST: the packet is sent with the link layer header pushed
* the packet is destroyed
*/
static void ip_direct_send(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct hh_cache *hh = dst->hh;
struct net_device *dev = dst->dev;
int hh_len = LL_RESERVED_SPACE(dev);
unsigned seq;
/* Be paranoid, rather than too clever. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
#else
if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) {
#endif
struct sk_buff *skb2;
skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
if (skb2 == NULL) {
kfree_skb(skb);
return;
}
if (skb->sk)
skb_set_owner_w(skb2, skb->sk);
kfree_skb(skb);
skb = skb2;
}
if (hh) {
do {
int hh_alen;
seq = read_seqbegin(&hh->hh_lock);
hh_alen = HH_DATA_ALIGN(hh->hh_len);
memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
} while (read_seqretry(&hh->hh_lock, seq));
skb_push(skb, hh->hh_len);
hh->hh_output(skb);
} else if (dst->neighbour)
dst->neighbour->output(skb);
else {
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ipt_ROUTE: no hdr & no neighbour cache!\n");
kfree_skb(skb);
}
}
/* PRE : skb->dev is set to the device we are leaving by
* POST: - the packet is directly sent to the skb->dev device, without
* pushing the link layer header.
* - the packet is destroyed
*/
static inline int dev_direct_send(struct sk_buff *skb)
{
return dev_queue_xmit(skb);
}
static unsigned int route_oif(const struct ipt_route_target_info *route_info,
struct sk_buff *skb)
{
unsigned int ifindex = 0;
struct net_device *dev_out = NULL;
/* The user set the interface name to use.
* Getting the current interface index.
*/
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
if ((dev_out = dev_get_by_name(&init_net, route_info->oif))) {
#else
if ((dev_out = dev_get_by_name(route_info->oif))) {
#endif
ifindex = dev_out->ifindex;
} else {
/* Unknown interface name : packet dropped */
if (net_ratelimit())
DEBUGP("ipt_ROUTE: oif interface %s not found\n", route_info->oif);
return NF_DROP;
}
/* Trying the standard way of routing packets */
switch (route(skb, ifindex, route_info)) {
case 1:
dev_put(dev_out);
if (route_info->flags & IPT_ROUTE_CONTINUE)
return IPT_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
case 0:
/* Failed to send to oif. Trying the hard way */
if (route_info->flags & IPT_ROUTE_CONTINUE)
return NF_DROP;
if (net_ratelimit())
DEBUGP("ipt_ROUTE: forcing the use of %i\n",
ifindex);
/* We have to force the use of an interface.
* This interface must be a tunnel interface since
* otherwise we can't guess the hw address for
* the packet. For a tunnel interface, no hw address
* is needed.
*/
if ((dev_out->type != ARPHRD_TUNNEL)
&& (dev_out->type != ARPHRD_IPGRE)) {
if (net_ratelimit())
DEBUGP("ipt_ROUTE: can't guess the hw addr !\n");
dev_put(dev_out);
return NF_DROP;
}
/* Send the packet. This will also free skb
* Do not go through the POST_ROUTING hook because
* skb->dst is not set and because it will probably
* get confused by the destination IP address.
*/
skb->dev = dev_out;
dev_direct_send(skb);
dev_put(dev_out);
return NF_STOLEN;
default:
/* Unexpected error */
dev_put(dev_out);
return NF_DROP;
}
}
static unsigned int route_iif(const struct ipt_route_target_info *route_info,
struct sk_buff *skb)
{
struct net_device *dev_in = NULL;
/* Getting the current interface index. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
if (!(dev_in = dev_get_by_name(&init_net, route_info->iif))) {
#else
if (!(dev_in = dev_get_by_name(route_info->iif))) {
#endif
if (net_ratelimit())
DEBUGP("ipt_ROUTE: iif interface %s not found\n", route_info->iif);
return NF_DROP;
}
skb->dev = dev_in;
dst_release(skb->dst);
skb->dst = NULL;
netif_rx(skb);
dev_put(dev_in);
return NF_STOLEN;
}
static unsigned int route_gw(const struct ipt_route_target_info *route_info,
struct sk_buff *skb)
{
if (route(skb, 0, route_info)!=1)
return NF_DROP;
if (route_info->flags & IPT_ROUTE_CONTINUE)
return IPT_CONTINUE;
ip_direct_send(skb);
return NF_STOLEN;
}
/* To detect and deter routed packet loopback when using the --tee option,
* we take a page out of the raw.patch book: on the copied skb, we set up
* a fake ->nfct entry, pointing to the local &route_tee_track. We skip
* routing packets when we see they already have that ->nfct.
*/
static struct nf_conn route_tee_track;
static unsigned int
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
target(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo,
void *userinfo)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
target(struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const void *targinfo,
void *userinfo)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
target(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)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
target(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)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
target(struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const struct xt_target *target,
const void *targinfo)
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28) */
target(struct sk_buff *skb,
const struct xt_target_param *par)
#endif
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
const struct ipt_route_target_info *route_info = targinfo;
#else
const struct ipt_route_target_info *route_info = par->targinfo;
unsigned int hooknum = par->hooknum;
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
struct sk_buff *skb = *pskb;
#endif
unsigned int res;
if (skb->nfct == &route_tee_track.ct_general) {
/* Loopback - a packet we already routed, is to be
* routed another time. Avoid that, now.
*/
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ipt_ROUTE: loopback - DROP!\n");
return NF_DROP;
}
/* If we are at PREROUTING or INPUT hook
* the TTL isn't decreased by the IP stack
*/
if (hooknum == NF_INET_PRE_ROUTING ||
hooknum == NF_INET_LOCAL_IN) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
struct iphdr *iph = ip_hdr(skb);
#else
struct iphdr *iph = skb->nh.iph;
#endif
if (iph->ttl <= 1) {
struct rtable *rt;
struct flowi fl = {
.oif = 0,
.nl_u = {
.ip4_u = {
.daddr = iph->daddr,
.saddr = iph->saddr,
.tos = RT_TOS(iph->tos),
.scope = ((iph->tos & RTO_ONLINK) ?
RT_SCOPE_LINK :
RT_SCOPE_UNIVERSE)
}
}
};
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
if (ip_route_output_key(&init_net, &rt, &fl)) {
#else
if (ip_route_output_key(&rt, &fl)) {
#endif
return NF_DROP;
}
if (skb->dev == rt->u.dst.dev) {
/* Drop old route. */
dst_release(skb->dst);
skb->dst = &rt->u.dst;
/* this will traverse normal stack, and
* thus call conntrack on the icmp packet */
icmp_send(skb, ICMP_TIME_EXCEEDED,
ICMP_EXC_TTL, 0);
}
return NF_DROP;
}
/*
* If we are at INPUT the checksum must be recalculated since
* the length could change as the result of a defragmentation.
*/
if(hooknum == NF_INET_LOCAL_IN) {
iph->ttl = iph->ttl - 1;
iph->check = 0;
iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
} else {
ip_decrease_ttl(iph);
}
}
if ((route_info->flags & IPT_ROUTE_TEE)) {
/*
* Copy the skb, and route the copy. Will later return
* IPT_CONTINUE for the original skb, which should continue
* on its way as if nothing happened. The copy should be
* independantly delivered to the ROUTE --gw.
*/
skb = skb_copy(skb, GFP_ATOMIC);
if (!skb) {
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ipt_ROUTE: copy failed!\n");
return IPT_CONTINUE;
}
}
/* Tell conntrack to forget this packet since it may get confused
* when a packet is leaving with dst address == our address.
* Good idea ? Dunno. Need advice.
*
* NEW: mark the skb with our &route_tee_track, so we avoid looping
* on any already routed packet.
*/
if (!(route_info->flags & IPT_ROUTE_CONTINUE)) {
nf_conntrack_put(skb->nfct);
skb->nfct = &route_tee_track.ct_general;
skb->nfctinfo = IP_CT_NEW;
nf_conntrack_get(skb->nfct);
}
if (route_info->oif[0] != '\0') {
res = route_oif(route_info, skb);
} else if (route_info->iif[0] != '\0') {
res = route_iif(route_info, skb);
} else if (route_info->gw) {
res = route_gw(route_info, skb);
} else {
if (net_ratelimit())
DEBUGP(KERN_DEBUG "ipt_ROUTE: no parameter !\n");
res = IPT_CONTINUE;
}
if ((route_info->flags & IPT_ROUTE_TEE))
res = IPT_CONTINUE;
return res;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
static int
checkentry(const char *tablename,
const struct ipt_entry *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
static int
checkentry(const char *tablename,
const void *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
static int
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
static int
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
static bool
checkentry(const char *tablename,
const void *e,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28) */
static bool
checkentry(const struct xt_tgchk_param *par)
#endif
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
const char *tablename = par->table;
unsigned int hook_mask = par->hook_mask;
#endif
if (strcmp(tablename, "mangle") != 0) {
printk("ipt_ROUTE: bad table `%s', use the `mangle' table.\n",
tablename);
return 0;
}
if (hook_mask & ~( (1 << NF_INET_PRE_ROUTING)
| (1 << NF_INET_LOCAL_IN)
| (1 << NF_INET_FORWARD)
| (1 << NF_INET_LOCAL_OUT)
| (1 << NF_INET_POST_ROUTING))) {
printk("ipt_ROUTE: bad hook\n");
return 0;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
if (targinfosize != IPT_ALIGN(sizeof(struct ipt_route_target_info))) {
printk(KERN_WARNING "ipt_ROUTE: targinfosize %u != %Zu\n",
targinfosize,
IPT_ALIGN(sizeof(struct ipt_route_target_info)));
return 0;
}
#endif
return 1;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
static struct ipt_target xt_route_reg = {
#else
static struct ipt_target ipt_route_reg = {
#endif
.name = "ROUTE",
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
.family = AF_INET,
#endif
.target = target,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
.targetsize = sizeof(struct ipt_route_target_info),
#endif
.checkentry = checkentry,
.me = THIS_MODULE,
};
static int __init init(void)
{
/* Set up fake conntrack (stolen from raw.patch):
- to never be deleted, not in any hashes */
atomic_set(&route_tee_track.ct_general.use, 1);
/* - and look it like as a confirmed connection */
set_bit(IPS_CONFIRMED_BIT, &route_tee_track.status);
/* Initialize fake conntrack so that NAT will skip it */
route_tee_track.status |= IPS_NAT_DONE_MASK;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
return xt_register_target(&xt_route_reg);
#else
return ipt_register_target(&ipt_route_reg);
#endif
}
static void __exit fini(void)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
xt_unregister_target(&xt_route_reg);
#else
ipt_unregister_target(&ipt_route_reg);
#endif
}
module_init(init);
module_exit(fini);
