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DEFINITIONS
This source file includes following definitions.
- __ipq_enqueue_entry
- __ipq_set_mode
- __ipq_reset
- ipq_find_dequeue_entry
- __ipq_flush
- ipq_flush
- ipq_build_packet_message
- ipq_enqueue_packet
- ipq_mangle_ipv6
- ipq_set_verdict
- ipq_set_mode
- ipq_receive_peer
- dev_cmp
- ipq_dev_drop
- __ipq_rcv_skb
- ipq_rcv_skb
- ipq_rcv_dev_event
- ipq_rcv_nl_event
- ip6_queue_show
- ip6_queue_open
- ip6_queue_init
- ip6_queue_fini
/*
* This is a module which is used for queueing IPv6 packets and
* communicating with userspace via netlink.
*
* (C) 2001 Fernando Anton, this code is GPL.
* IPv64 Project - Work based in IPv64 draft by Arturo Azcorra.
* Universidad Carlos III de Madrid - Leganes (Madrid) - Spain
* Universidad Politecnica de Alcala de Henares - Alcala de H. (Madrid) - Spain
* email: fanton@it.uc3m.es
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/ipv6.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/netlink.h>
#include <linux/spinlock.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/netfilter/nf_queue.h>
#include <linux/netfilter_ipv4/ip_queue.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#define IPQ_QMAX_DEFAULT 1024
#define IPQ_PROC_FS_NAME "ip6_queue"
#define NET_IPQ_QMAX 2088
#define NET_IPQ_QMAX_NAME "ip6_queue_maxlen"
typedef int (*ipq_cmpfn)(struct nf_queue_entry *, unsigned long);
static unsigned char copy_mode __read_mostly = IPQ_COPY_NONE;
static unsigned int queue_maxlen __read_mostly = IPQ_QMAX_DEFAULT;
static DEFINE_RWLOCK(queue_lock);
static int peer_pid __read_mostly;
static unsigned int copy_range __read_mostly;
static unsigned int queue_total;
static unsigned int queue_dropped = 0;
static unsigned int queue_user_dropped = 0;
static struct sock *ipqnl __read_mostly;
static LIST_HEAD(queue_list);
static DEFINE_MUTEX(ipqnl_mutex);
static inline void
__ipq_enqueue_entry(struct nf_queue_entry *entry)
{
list_add_tail(&entry->list, &queue_list);
queue_total++;
}
static inline int
__ipq_set_mode(unsigned char mode, unsigned int range)
{
int status = 0;
switch(mode) {
case IPQ_COPY_NONE:
case IPQ_COPY_META:
copy_mode = mode;
copy_range = 0;
break;
case IPQ_COPY_PACKET:
copy_mode = mode;
copy_range = range;
if (copy_range > 0xFFFF)
copy_range = 0xFFFF;
break;
default:
status = -EINVAL;
}
return status;
}
static void __ipq_flush(ipq_cmpfn cmpfn, unsigned long data);
static inline void
__ipq_reset(void)
{
peer_pid = 0;
net_disable_timestamp();
__ipq_set_mode(IPQ_COPY_NONE, 0);
__ipq_flush(NULL, 0);
}
static struct nf_queue_entry *
ipq_find_dequeue_entry(unsigned long id)
{
struct nf_queue_entry *entry = NULL, *i;
write_lock_bh(&queue_lock);
list_for_each_entry(i, &queue_list, list) {
if ((unsigned long)i == id) {
entry = i;
break;
}
}
if (entry) {
list_del(&entry->list);
queue_total--;
}
write_unlock_bh(&queue_lock);
return entry;
}
static void
__ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
{
struct nf_queue_entry *entry, *next;
list_for_each_entry_safe(entry, next, &queue_list, list) {
if (!cmpfn || cmpfn(entry, data)) {
list_del(&entry->list);
queue_total--;
nf_reinject(entry, NF_DROP);
}
}
}
static void
ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
{
write_lock_bh(&queue_lock);
__ipq_flush(cmpfn, data);
write_unlock_bh(&queue_lock);
}
static struct sk_buff *
ipq_build_packet_message(struct nf_queue_entry *entry, int *errp)
{
sk_buff_data_t old_tail;
size_t size = 0;
size_t data_len = 0;
struct sk_buff *skb;
struct ipq_packet_msg *pmsg;
struct nlmsghdr *nlh;
struct timeval tv;
read_lock_bh(&queue_lock);
switch (copy_mode) {
case IPQ_COPY_META:
case IPQ_COPY_NONE:
size = NLMSG_SPACE(sizeof(*pmsg));
break;
case IPQ_COPY_PACKET:
if ((entry->skb->ip_summed == CHECKSUM_PARTIAL ||
entry->skb->ip_summed == CHECKSUM_COMPLETE) &&
(*errp = skb_checksum_help(entry->skb))) {
read_unlock_bh(&queue_lock);
return NULL;
}
if (copy_range == 0 || copy_range > entry->skb->len)
data_len = entry->skb->len;
else
data_len = copy_range;
size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
break;
default:
*errp = -EINVAL;
read_unlock_bh(&queue_lock);
return NULL;
}
read_unlock_bh(&queue_lock);
skb = alloc_skb(size, GFP_ATOMIC);
if (!skb)
goto nlmsg_failure;
old_tail = skb->tail;
nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
pmsg = NLMSG_DATA(nlh);
memset(pmsg, 0, sizeof(*pmsg));
pmsg->packet_id = (unsigned long )entry;
pmsg->data_len = data_len;
tv = ktime_to_timeval(entry->skb->tstamp);
pmsg->timestamp_sec = tv.tv_sec;
pmsg->timestamp_usec = tv.tv_usec;
pmsg->mark = entry->skb->mark;
pmsg->hook = entry->hook;
pmsg->hw_protocol = entry->skb->protocol;
if (entry->indev)
strcpy(pmsg->indev_name, entry->indev->name);
else
pmsg->indev_name[0] = '\0';
if (entry->outdev)
strcpy(pmsg->outdev_name, entry->outdev->name);
else
pmsg->outdev_name[0] = '\0';
if (entry->indev && entry->skb->dev) {
pmsg->hw_type = entry->skb->dev->type;
pmsg->hw_addrlen = dev_parse_header(entry->skb, pmsg->hw_addr);
}
if (data_len)
if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
BUG();
nlh->nlmsg_len = skb->tail - old_tail;
return skb;
nlmsg_failure:
*errp = -EINVAL;
printk(KERN_ERR "ip6_queue: error creating packet message\n");
return NULL;
}
static int
ipq_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
int status = -EINVAL;
struct sk_buff *nskb;
if (copy_mode == IPQ_COPY_NONE)
return -EAGAIN;
nskb = ipq_build_packet_message(entry, &status);
if (nskb == NULL)
return status;
write_lock_bh(&queue_lock);
if (!peer_pid)
goto err_out_free_nskb;
if (queue_total >= queue_maxlen) {
queue_dropped++;
status = -ENOSPC;
if (net_ratelimit())
printk (KERN_WARNING "ip6_queue: fill at %d entries, "
"dropping packet(s). Dropped: %d\n", queue_total,
queue_dropped);
goto err_out_free_nskb;
}
/* netlink_unicast will either free the nskb or attach it to a socket */
status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
if (status < 0) {
queue_user_dropped++;
goto err_out_unlock;
}
__ipq_enqueue_entry(entry);
write_unlock_bh(&queue_lock);
return status;
err_out_free_nskb:
kfree_skb(nskb);
err_out_unlock:
write_unlock_bh(&queue_lock);
return status;
}
static int
ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
{
int diff;
struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
struct sk_buff *nskb;
if (v->data_len < sizeof(*user_iph))
return 0;
diff = v->data_len - e->skb->len;
if (diff < 0) {
if (pskb_trim(e->skb, v->data_len))
return -ENOMEM;
} else if (diff > 0) {
if (v->data_len > 0xFFFF)
return -EINVAL;
if (diff > skb_tailroom(e->skb)) {
nskb = skb_copy_expand(e->skb, skb_headroom(e->skb),
diff, GFP_ATOMIC);
if (!nskb) {
printk(KERN_WARNING "ip6_queue: OOM "
"in mangle, dropping packet\n");
return -ENOMEM;
}
kfree_skb(e->skb);
e->skb = nskb;
}
skb_put(e->skb, diff);
}
if (!skb_make_writable(e->skb, v->data_len))
return -ENOMEM;
skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
e->skb->ip_summed = CHECKSUM_NONE;
return 0;
}
static int
ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
{
struct nf_queue_entry *entry;
if (vmsg->value > NF_MAX_VERDICT)
return -EINVAL;
entry = ipq_find_dequeue_entry(vmsg->id);
if (entry == NULL)
return -ENOENT;
else {
int verdict = vmsg->value;
if (vmsg->data_len && vmsg->data_len == len)
if (ipq_mangle_ipv6(vmsg, entry) < 0)
verdict = NF_DROP;
nf_reinject(entry, verdict);
return 0;
}
}
static int
ipq_set_mode(unsigned char mode, unsigned int range)
{
int status;
write_lock_bh(&queue_lock);
status = __ipq_set_mode(mode, range);
write_unlock_bh(&queue_lock);
return status;
}
static int
ipq_receive_peer(struct ipq_peer_msg *pmsg,
unsigned char type, unsigned int len)
{
int status = 0;
if (len < sizeof(*pmsg))
return -EINVAL;
switch (type) {
case IPQM_MODE:
status = ipq_set_mode(pmsg->msg.mode.value,
pmsg->msg.mode.range);
break;
case IPQM_VERDICT:
if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
status = -EINVAL;
else
status = ipq_set_verdict(&pmsg->msg.verdict,
len - sizeof(*pmsg));
break;
default:
status = -EINVAL;
}
return status;
}
static int
dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
{
if (entry->indev)
if (entry->indev->ifindex == ifindex)
return 1;
if (entry->outdev)
if (entry->outdev->ifindex == ifindex)
return 1;
#ifdef CONFIG_BRIDGE_NETFILTER
if (entry->skb->nf_bridge) {
if (entry->skb->nf_bridge->physindev &&
entry->skb->nf_bridge->physindev->ifindex == ifindex)
return 1;
if (entry->skb->nf_bridge->physoutdev &&
entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
return 1;
}
#endif
return 0;
}
static void
ipq_dev_drop(int ifindex)
{
ipq_flush(dev_cmp, ifindex);
}
#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
static inline void
__ipq_rcv_skb(struct sk_buff *skb)
{
int status, type, pid, flags, nlmsglen, skblen;
struct nlmsghdr *nlh;
skblen = skb->len;
if (skblen < sizeof(*nlh))
return;
nlh = nlmsg_hdr(skb);
nlmsglen = nlh->nlmsg_len;
if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
return;
pid = nlh->nlmsg_pid;
flags = nlh->nlmsg_flags;
if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
RCV_SKB_FAIL(-EINVAL);
if (flags & MSG_TRUNC)
RCV_SKB_FAIL(-ECOMM);
type = nlh->nlmsg_type;
if (type < NLMSG_NOOP || type >= IPQM_MAX)
RCV_SKB_FAIL(-EINVAL);
if (type <= IPQM_BASE)
return;
if (security_netlink_recv(skb, CAP_NET_ADMIN))
RCV_SKB_FAIL(-EPERM);
write_lock_bh(&queue_lock);
if (peer_pid) {
if (peer_pid != pid) {
write_unlock_bh(&queue_lock);
RCV_SKB_FAIL(-EBUSY);
}
} else {
net_enable_timestamp();
peer_pid = pid;
}
write_unlock_bh(&queue_lock);
status = ipq_receive_peer(NLMSG_DATA(nlh), type,
nlmsglen - NLMSG_LENGTH(0));
if (status < 0)
RCV_SKB_FAIL(status);
if (flags & NLM_F_ACK)
netlink_ack(skb, nlh, 0);
return;
}
static void
ipq_rcv_skb(struct sk_buff *skb)
{
mutex_lock(&ipqnl_mutex);
__ipq_rcv_skb(skb);
mutex_unlock(&ipqnl_mutex);
}
static int
ipq_rcv_dev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
if (!net_eq(dev_net(dev), &init_net))
return NOTIFY_DONE;
/* Drop any packets associated with the downed device */
if (event == NETDEV_DOWN)
ipq_dev_drop(dev->ifindex);
return NOTIFY_DONE;
}
static struct notifier_block ipq_dev_notifier = {
.notifier_call = ipq_rcv_dev_event,
};
static int
ipq_rcv_nl_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct netlink_notify *n = ptr;
if (event == NETLINK_URELEASE &&
n->protocol == NETLINK_IP6_FW && n->pid) {
write_lock_bh(&queue_lock);
if ((n->net == &init_net) && (n->pid == peer_pid))
__ipq_reset();
write_unlock_bh(&queue_lock);
}
return NOTIFY_DONE;
}
static struct notifier_block ipq_nl_notifier = {
.notifier_call = ipq_rcv_nl_event,
};
#ifdef CONFIG_SYSCTL
static struct ctl_table_header *ipq_sysctl_header;
static ctl_table ipq_table[] = {
{
.ctl_name = NET_IPQ_QMAX,
.procname = NET_IPQ_QMAX_NAME,
.data = &queue_maxlen,
.maxlen = sizeof(queue_maxlen),
.mode = 0644,
.proc_handler = proc_dointvec
},
{ .ctl_name = 0 }
};
#endif
#ifdef CONFIG_PROC_FS
static int ip6_queue_show(struct seq_file *m, void *v)
{
read_lock_bh(&queue_lock);
seq_printf(m,
"Peer PID : %d\n"
"Copy mode : %hu\n"
"Copy range : %u\n"
"Queue length : %u\n"
"Queue max. length : %u\n"
"Queue dropped : %u\n"
"Netfilter dropped : %u\n",
peer_pid,
copy_mode,
copy_range,
queue_total,
queue_maxlen,
queue_dropped,
queue_user_dropped);
read_unlock_bh(&queue_lock);
return 0;
}
static int ip6_queue_open(struct inode *inode, struct file *file)
{
return single_open(file, ip6_queue_show, NULL);
}
static const struct file_operations ip6_queue_proc_fops = {
.open = ip6_queue_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.owner = THIS_MODULE,
};
#endif
static const struct nf_queue_handler nfqh = {
.name = "ip6_queue",
.outfn = &ipq_enqueue_packet,
};
static int __init ip6_queue_init(void)
{
int status = -ENOMEM;
struct proc_dir_entry *proc __maybe_unused;
netlink_register_notifier(&ipq_nl_notifier);
ipqnl = netlink_kernel_create(&init_net, NETLINK_IP6_FW, 0,
ipq_rcv_skb, NULL, THIS_MODULE);
if (ipqnl == NULL) {
printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
goto cleanup_netlink_notifier;
}
#ifdef CONFIG_PROC_FS
proc = proc_create(IPQ_PROC_FS_NAME, 0, init_net.proc_net,
&ip6_queue_proc_fops);
if (!proc) {
printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
goto cleanup_ipqnl;
}
#endif
register_netdevice_notifier(&ipq_dev_notifier);
#ifdef CONFIG_SYSCTL
ipq_sysctl_header = register_sysctl_paths(net_ipv6_ctl_path, ipq_table);
#endif
status = nf_register_queue_handler(PF_INET6, &nfqh);
if (status < 0) {
printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
goto cleanup_sysctl;
}
return status;
cleanup_sysctl:
#ifdef CONFIG_SYSCTL
unregister_sysctl_table(ipq_sysctl_header);
#endif
unregister_netdevice_notifier(&ipq_dev_notifier);
proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
cleanup_ipqnl: __maybe_unused
netlink_kernel_release(ipqnl);
mutex_lock(&ipqnl_mutex);
mutex_unlock(&ipqnl_mutex);
cleanup_netlink_notifier:
netlink_unregister_notifier(&ipq_nl_notifier);
return status;
}
static void __exit ip6_queue_fini(void)
{
nf_unregister_queue_handlers(&nfqh);
synchronize_net();
ipq_flush(NULL, 0);
#ifdef CONFIG_SYSCTL
unregister_sysctl_table(ipq_sysctl_header);
#endif
unregister_netdevice_notifier(&ipq_dev_notifier);
proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
netlink_kernel_release(ipqnl);
mutex_lock(&ipqnl_mutex);
mutex_unlock(&ipqnl_mutex);
netlink_unregister_notifier(&ipq_nl_notifier);
}
MODULE_DESCRIPTION("IPv6 packet queue handler");
MODULE_LICENSE("GPL");
module_init(ip6_queue_init);
module_exit(ip6_queue_fini);