diff options
Diffstat (limited to 'net/ipv6/netfilter/ip6_queue.c')
-rw-r--r-- | net/ipv6/netfilter/ip6_queue.c | 741 |
1 files changed, 741 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c new file mode 100644 index 000000000000..c54830b89593 --- /dev/null +++ b/net/ipv6/netfilter/ip6_queue.c @@ -0,0 +1,741 @@ +/* + * 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. + * + * 2001-11-06: First try. Working with ip_queue.c for IPv4 and trying + * to adapt it to IPv6 + * HEAVILY based in ipqueue.c by James Morris. It's just + * a little modified version of it, so he's nearly the + * real coder of this. + * Few changes needed, mainly the hard_routing code and + * the netlink socket protocol (we're NETLINK_IP6_FW). + * 2002-06-25: Code cleanup. [JM: ported cleanup over from ip_queue.c] + * 2005-02-04: 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/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 <net/sock.h> +#include <net/ipv6.h> +#include <net/ip6_route.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" + +struct ipq_rt_info { + struct in6_addr daddr; + struct in6_addr 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 "ip6_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 "ip6_queue: OOM in ipq_enqueue_packet()\n"); + return -ENOMEM; + } + + entry->info = info; + entry->skb = skb; + + if (entry->info->hook == NF_IP_LOCAL_OUT) { + struct ipv6hdr *iph = skb->nh.ipv6h; + + 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 "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); + +err_out_free: + kfree(entry); + return status; +} + +static int +ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e) +{ + int diff; + struct ipv6hdr *user_iph = (struct ipv6hdr *)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 "ip6_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. + * Not a nice way to cmp, but works + */ + if (e->info->hook == NF_IP_LOCAL_OUT) { + struct ipv6hdr *iph = e->skb->nh.ipv6h; + if (!ipv6_addr_equal(&iph->daddr, &e->rt_info.daddr) || + !ipv6_addr_equal(&iph->saddr, &e->rt_info.saddr)) + return ip6_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_ipv6(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_IP6_FW && 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_IPV6, + .procname = "ipv6", + .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 } +}; + +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" + "Netfilter 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; +} + +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_IP6_FW, ipq_rcv_sk); + if (ipqnl == NULL) { + printk(KERN_ERR "ip6_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 "ip6_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_INET6, ipq_enqueue_packet, NULL); + if (status < 0) { + printk(KERN_ERR "ip6_queue: failed to register queue handler\n"); + goto cleanup_sysctl; + } + return status; + +cleanup: + nf_unregister_queue_handler(PF_INET6); + 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("IPv6 packet queue handler"); +MODULE_LICENSE("GPL"); + +module_init(init); +module_exit(fini); |