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Diffstat (limited to 'net/ipv4/netfilter/ip_queue.c')
-rw-r--r--net/ipv4/netfilter/ip_queue.c741
1 files changed, 741 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
new file mode 100644
index 00000000000..9e40dffc204
--- /dev/null
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -0,0 +1,741 @@
+/*
+ * This is a module which is used for queueing IPv4 packets and
+ * communicating with userspace via netlink.
+ *
+ * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
+ *
+ * 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.
+ *
+ * 2000-03-27: Simplified code (thanks to Andi Kleen for clues).
+ * 2000-05-20: Fixed notifier problems (following Miguel Freitas' report).
+ * 2000-06-19: Fixed so nfmark is copied to metadata (reported by Sebastian
+ * Zander).
+ * 2000-08-01: Added Nick Williams' MAC support.
+ * 2002-06-25: Code cleanup.
+ * 2005-01-10: Added /proc counter for dropped packets; fixed so
+ * packets aren't delivered to user space if they're going
+ * to be dropped.
+ *
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+#include <linux/ip.h>
+#include <linux/notifier.h>
+#include <linux/netdevice.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4/ip_queue.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netlink.h>
+#include <linux/spinlock.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
+#include <linux/security.h>
+#include <net/sock.h>
+#include <net/route.h>
+
+#define IPQ_QMAX_DEFAULT 1024
+#define IPQ_PROC_FS_NAME "ip_queue"
+#define NET_IPQ_QMAX 2088
+#define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
+
+struct ipq_rt_info {
+ __u8 tos;
+ __u32 daddr;
+ __u32 saddr;
+};
+
+struct ipq_queue_entry {
+ struct list_head list;
+ struct nf_info *info;
+ struct sk_buff *skb;
+ struct ipq_rt_info rt_info;
+};
+
+typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
+
+static unsigned char copy_mode = IPQ_COPY_NONE;
+static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
+static DEFINE_RWLOCK(queue_lock);
+static int peer_pid;
+static unsigned int copy_range;
+static unsigned int queue_total;
+static unsigned int queue_dropped = 0;
+static unsigned int queue_user_dropped = 0;
+static struct sock *ipqnl;
+static LIST_HEAD(queue_list);
+static DECLARE_MUTEX(ipqnl_sem);
+
+static void
+ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
+{
+ nf_reinject(entry->skb, entry->info, verdict);
+ kfree(entry);
+}
+
+static inline void
+__ipq_enqueue_entry(struct ipq_queue_entry *entry)
+{
+ list_add(&entry->list, &queue_list);
+ queue_total++;
+}
+
+/*
+ * Find and return a queued entry matched by cmpfn, or return the last
+ * entry if cmpfn is NULL.
+ */
+static inline struct ipq_queue_entry *
+__ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
+{
+ struct list_head *p;
+
+ list_for_each_prev(p, &queue_list) {
+ struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
+
+ if (!cmpfn || cmpfn(entry, data))
+ return entry;
+ }
+ return NULL;
+}
+
+static inline void
+__ipq_dequeue_entry(struct ipq_queue_entry *entry)
+{
+ list_del(&entry->list);
+ queue_total--;
+}
+
+static inline struct ipq_queue_entry *
+__ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
+{
+ struct ipq_queue_entry *entry;
+
+ entry = __ipq_find_entry(cmpfn, data);
+ if (entry == NULL)
+ return NULL;
+
+ __ipq_dequeue_entry(entry);
+ return entry;
+}
+
+
+static inline void
+__ipq_flush(int verdict)
+{
+ struct ipq_queue_entry *entry;
+
+ while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
+ ipq_issue_verdict(entry, verdict);
+}
+
+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 inline void
+__ipq_reset(void)
+{
+ peer_pid = 0;
+ net_disable_timestamp();
+ __ipq_set_mode(IPQ_COPY_NONE, 0);
+ __ipq_flush(NF_DROP);
+}
+
+static struct ipq_queue_entry *
+ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
+{
+ struct ipq_queue_entry *entry;
+
+ write_lock_bh(&queue_lock);
+ entry = __ipq_find_dequeue_entry(cmpfn, data);
+ write_unlock_bh(&queue_lock);
+ return entry;
+}
+
+static void
+ipq_flush(int verdict)
+{
+ write_lock_bh(&queue_lock);
+ __ipq_flush(verdict);
+ write_unlock_bh(&queue_lock);
+}
+
+static struct sk_buff *
+ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
+{
+ unsigned char *old_tail;
+ size_t size = 0;
+ size_t data_len = 0;
+ struct sk_buff *skb;
+ struct ipq_packet_msg *pmsg;
+ struct nlmsghdr *nlh;
+
+ read_lock_bh(&queue_lock);
+
+ switch (copy_mode) {
+ case IPQ_COPY_META:
+ case IPQ_COPY_NONE:
+ size = NLMSG_SPACE(sizeof(*pmsg));
+ data_len = 0;
+ break;
+
+ case IPQ_COPY_PACKET:
+ 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;
+ pmsg->timestamp_sec = entry->skb->stamp.tv_sec;
+ pmsg->timestamp_usec = entry->skb->stamp.tv_usec;
+ pmsg->mark = entry->skb->nfmark;
+ pmsg->hook = entry->info->hook;
+ pmsg->hw_protocol = entry->skb->protocol;
+
+ if (entry->info->indev)
+ strcpy(pmsg->indev_name, entry->info->indev->name);
+ else
+ pmsg->indev_name[0] = '\0';
+
+ if (entry->info->outdev)
+ strcpy(pmsg->outdev_name, entry->info->outdev->name);
+ else
+ pmsg->outdev_name[0] = '\0';
+
+ if (entry->info->indev && entry->skb->dev) {
+ pmsg->hw_type = entry->skb->dev->type;
+ if (entry->skb->dev->hard_header_parse)
+ pmsg->hw_addrlen =
+ entry->skb->dev->hard_header_parse(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:
+ if (skb)
+ kfree_skb(skb);
+ *errp = -EINVAL;
+ printk(KERN_ERR "ip_queue: error creating packet message\n");
+ return NULL;
+}
+
+static int
+ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
+{
+ int status = -EINVAL;
+ struct sk_buff *nskb;
+ struct ipq_queue_entry *entry;
+
+ if (copy_mode == IPQ_COPY_NONE)
+ return -EAGAIN;
+
+ entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ if (entry == NULL) {
+ printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
+ return -ENOMEM;
+ }
+
+ entry->info = info;
+ entry->skb = skb;
+
+ if (entry->info->hook == NF_IP_LOCAL_OUT) {
+ struct iphdr *iph = skb->nh.iph;
+
+ entry->rt_info.tos = iph->tos;
+ entry->rt_info.daddr = iph->daddr;
+ entry->rt_info.saddr = iph->saddr;
+ }
+
+ nskb = ipq_build_packet_message(entry, &status);
+ if (nskb == NULL)
+ goto err_out_free;
+
+ 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 "ip_queue: full at %d entries, "
+ "dropping packets(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);
+
+err_out_free:
+ kfree(entry);
+ return status;
+}
+
+static int
+ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
+{
+ int diff;
+ struct iphdr *user_iph = (struct iphdr *)v->payload;
+
+ if (v->data_len < sizeof(*user_iph))
+ return 0;
+ diff = v->data_len - e->skb->len;
+ if (diff < 0)
+ skb_trim(e->skb, v->data_len);
+ else if (diff > 0) {
+ if (v->data_len > 0xFFFF)
+ return -EINVAL;
+ if (diff > skb_tailroom(e->skb)) {
+ struct sk_buff *newskb;
+
+ newskb = skb_copy_expand(e->skb,
+ skb_headroom(e->skb),
+ diff,
+ GFP_ATOMIC);
+ if (newskb == NULL) {
+ printk(KERN_WARNING "ip_queue: OOM "
+ "in mangle, dropping packet\n");
+ return -ENOMEM;
+ }
+ if (e->skb->sk)
+ skb_set_owner_w(newskb, e->skb->sk);
+ kfree_skb(e->skb);
+ e->skb = newskb;
+ }
+ skb_put(e->skb, diff);
+ }
+ if (!skb_ip_make_writable(&e->skb, v->data_len))
+ return -ENOMEM;
+ memcpy(e->skb->data, v->payload, v->data_len);
+ e->skb->nfcache |= NFC_ALTERED;
+
+ /*
+ * Extra routing may needed on local out, as the QUEUE target never
+ * returns control to the table.
+ */
+ if (e->info->hook == NF_IP_LOCAL_OUT) {
+ struct iphdr *iph = e->skb->nh.iph;
+
+ if (!(iph->tos == e->rt_info.tos
+ && iph->daddr == e->rt_info.daddr
+ && iph->saddr == e->rt_info.saddr))
+ return ip_route_me_harder(&e->skb);
+ }
+ return 0;
+}
+
+static inline int
+id_cmp(struct ipq_queue_entry *e, unsigned long id)
+{
+ return (id == (unsigned long )e);
+}
+
+static int
+ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
+{
+ struct ipq_queue_entry *entry;
+
+ if (vmsg->value > NF_MAX_VERDICT)
+ return -EINVAL;
+
+ entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
+ if (entry == NULL)
+ return -ENOENT;
+ else {
+ int verdict = vmsg->value;
+
+ if (vmsg->data_len && vmsg->data_len == len)
+ if (ipq_mangle_ipv4(vmsg, entry) < 0)
+ verdict = NF_DROP;
+
+ ipq_issue_verdict(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 ipq_queue_entry *entry, unsigned long ifindex)
+{
+ if (entry->info->indev)
+ if (entry->info->indev->ifindex == ifindex)
+ return 1;
+
+ if (entry->info->outdev)
+ if (entry->info->outdev->ifindex == ifindex)
+ return 1;
+
+ return 0;
+}
+
+static void
+ipq_dev_drop(int ifindex)
+{
+ struct ipq_queue_entry *entry;
+
+ while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
+ ipq_issue_verdict(entry, NF_DROP);
+}
+
+#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 = (struct nlmsghdr *)skb->data;
+ 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))
+ 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,
+ skblen - 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_sk(struct sock *sk, int len)
+{
+ do {
+ struct sk_buff *skb;
+
+ if (down_trylock(&ipqnl_sem))
+ return;
+
+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+ ipq_rcv_skb(skb);
+ kfree_skb(skb);
+ }
+
+ up(&ipqnl_sem);
+
+ } while (ipqnl && ipqnl->sk_receive_queue.qlen);
+}
+
+static int
+ipq_rcv_dev_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+
+ /* 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_FIREWALL && n->pid) {
+ write_lock_bh(&queue_lock);
+ if (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,
+};
+
+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 }
+};
+
+static ctl_table ipq_dir_table[] = {
+ {
+ .ctl_name = NET_IPV4,
+ .procname = "ipv4",
+ .mode = 0555,
+ .child = ipq_table
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table ipq_root_table[] = {
+ {
+ .ctl_name = CTL_NET,
+ .procname = "net",
+ .mode = 0555,
+ .child = ipq_dir_table
+ },
+ { .ctl_name = 0 }
+};
+
+#ifdef CONFIG_PROC_FS
+static int
+ipq_get_info(char *buffer, char **start, off_t offset, int length)
+{
+ int len;
+
+ read_lock_bh(&queue_lock);
+
+ len = sprintf(buffer,
+ "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"
+ "Netlink dropped : %u\n",
+ peer_pid,
+ copy_mode,
+ copy_range,
+ queue_total,
+ queue_maxlen,
+ queue_dropped,
+ queue_user_dropped);
+
+ read_unlock_bh(&queue_lock);
+
+ *start = buffer + offset;
+ len -= offset;
+ if (len > length)
+ len = length;
+ else if (len < 0)
+ len = 0;
+ return len;
+}
+#endif /* CONFIG_PROC_FS */
+
+static int
+init_or_cleanup(int init)
+{
+ int status = -ENOMEM;
+ struct proc_dir_entry *proc;
+
+ if (!init)
+ goto cleanup;
+
+ netlink_register_notifier(&ipq_nl_notifier);
+ ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk);
+ if (ipqnl == NULL) {
+ printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
+ goto cleanup_netlink_notifier;
+ }
+
+ proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
+ if (proc)
+ proc->owner = THIS_MODULE;
+ else {
+ printk(KERN_ERR "ip_queue: failed to create proc entry\n");
+ goto cleanup_ipqnl;
+ }
+
+ register_netdevice_notifier(&ipq_dev_notifier);
+ ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
+
+ status = nf_register_queue_handler(PF_INET, ipq_enqueue_packet, NULL);
+ if (status < 0) {
+ printk(KERN_ERR "ip_queue: failed to register queue handler\n");
+ goto cleanup_sysctl;
+ }
+ return status;
+
+cleanup:
+ nf_unregister_queue_handler(PF_INET);
+ synchronize_net();
+ ipq_flush(NF_DROP);
+
+cleanup_sysctl:
+ unregister_sysctl_table(ipq_sysctl_header);
+ unregister_netdevice_notifier(&ipq_dev_notifier);
+ proc_net_remove(IPQ_PROC_FS_NAME);
+
+cleanup_ipqnl:
+ sock_release(ipqnl->sk_socket);
+ down(&ipqnl_sem);
+ up(&ipqnl_sem);
+
+cleanup_netlink_notifier:
+ netlink_unregister_notifier(&ipq_nl_notifier);
+ return status;
+}
+
+static int __init init(void)
+{
+
+ return init_or_cleanup(1);
+}
+
+static void __exit fini(void)
+{
+ init_or_cleanup(0);
+}
+
+MODULE_DESCRIPTION("IPv4 packet queue handler");
+MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
+MODULE_LICENSE("GPL");
+
+module_init(init);
+module_exit(fini);