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- /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
- *
- * 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/types.h>
- #include <linux/timer.h>
- #include <linux/module.h>
- #include <linux/udp.h>
- #include <linux/seq_file.h>
- #include <linux/skbuff.h>
- #include <linux/ipv6.h>
- #include <net/ip6_checksum.h>
- #include <net/checksum.h>
- #include <linux/netfilter.h>
- #include <linux/netfilter_ipv4.h>
- #include <linux/netfilter_ipv6.h>
- #include <net/netfilter/nf_conntrack_l4proto.h>
- #include <net/netfilter/nf_conntrack_ecache.h>
- #include <net/netfilter/nf_log.h>
- #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
- #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
- static unsigned int udp_timeouts[UDP_CT_MAX] = {
- [UDP_CT_UNREPLIED] = 30*HZ,
- [UDP_CT_REPLIED] = 180*HZ,
- };
- static inline struct nf_udp_net *udp_pernet(struct net *net)
- {
- return &net->ct.nf_ct_proto.udp;
- }
- static bool udp_pkt_to_tuple(const struct sk_buff *skb,
- unsigned int dataoff,
- struct net *net,
- struct nf_conntrack_tuple *tuple)
- {
- const struct udphdr *hp;
- struct udphdr _hdr;
- /* Actually only need first 8 bytes. */
- hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
- if (hp == NULL)
- return false;
- tuple->src.u.udp.port = hp->source;
- tuple->dst.u.udp.port = hp->dest;
- return true;
- }
- static bool udp_invert_tuple(struct nf_conntrack_tuple *tuple,
- const struct nf_conntrack_tuple *orig)
- {
- tuple->src.u.udp.port = orig->dst.u.udp.port;
- tuple->dst.u.udp.port = orig->src.u.udp.port;
- return true;
- }
- /* Print out the per-protocol part of the tuple. */
- static void udp_print_tuple(struct seq_file *s,
- const struct nf_conntrack_tuple *tuple)
- {
- seq_printf(s, "sport=%hu dport=%hu ",
- ntohs(tuple->src.u.udp.port),
- ntohs(tuple->dst.u.udp.port));
- }
- static unsigned int *udp_get_timeouts(struct net *net)
- {
- return udp_pernet(net)->timeouts;
- }
- /* Returns verdict for packet, and may modify conntracktype */
- static int udp_packet(struct nf_conn *ct,
- const struct sk_buff *skb,
- unsigned int dataoff,
- enum ip_conntrack_info ctinfo,
- u_int8_t pf,
- unsigned int hooknum,
- unsigned int *timeouts)
- {
- /* If we've seen traffic both ways, this is some kind of UDP
- stream. Extend timeout. */
- if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
- nf_ct_refresh_acct(ct, ctinfo, skb,
- timeouts[UDP_CT_REPLIED]);
- /* Also, more likely to be important, and not a probe */
- if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
- nf_conntrack_event_cache(IPCT_ASSURED, ct);
- } else {
- nf_ct_refresh_acct(ct, ctinfo, skb,
- timeouts[UDP_CT_UNREPLIED]);
- }
- return NF_ACCEPT;
- }
- /* Called when a new connection for this protocol found. */
- static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb,
- unsigned int dataoff, unsigned int *timeouts)
- {
- return true;
- }
- static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
- unsigned int dataoff, enum ip_conntrack_info *ctinfo,
- u_int8_t pf,
- unsigned int hooknum)
- {
- unsigned int udplen = skb->len - dataoff;
- const struct udphdr *hdr;
- struct udphdr _hdr;
- /* Header is too small? */
- hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
- if (hdr == NULL) {
- if (LOG_INVALID(net, IPPROTO_UDP))
- nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
- "nf_ct_udp: short packet ");
- return -NF_ACCEPT;
- }
- /* Truncated/malformed packets */
- if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
- if (LOG_INVALID(net, IPPROTO_UDP))
- nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
- "nf_ct_udp: truncated/malformed packet ");
- return -NF_ACCEPT;
- }
- /* Packet with no checksum */
- if (!hdr->check)
- return NF_ACCEPT;
- /* Checksum invalid? Ignore.
- * We skip checking packets on the outgoing path
- * because the checksum is assumed to be correct.
- * FIXME: Source route IP option packets --RR */
- if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
- nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
- if (LOG_INVALID(net, IPPROTO_UDP))
- nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
- "nf_ct_udp: bad UDP checksum ");
- return -NF_ACCEPT;
- }
- return NF_ACCEPT;
- }
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
- #include <linux/netfilter/nfnetlink.h>
- #include <linux/netfilter/nfnetlink_cttimeout.h>
- static int udp_timeout_nlattr_to_obj(struct nlattr *tb[],
- struct net *net, void *data)
- {
- unsigned int *timeouts = data;
- struct nf_udp_net *un = udp_pernet(net);
- /* set default timeouts for UDP. */
- timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED];
- timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED];
- if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
- timeouts[UDP_CT_UNREPLIED] =
- ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
- }
- if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
- timeouts[UDP_CT_REPLIED] =
- ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
- }
- return 0;
- }
- static int
- udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
- {
- const unsigned int *timeouts = data;
- if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
- htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) ||
- nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED,
- htonl(timeouts[UDP_CT_REPLIED] / HZ)))
- goto nla_put_failure;
- return 0;
- nla_put_failure:
- return -ENOSPC;
- }
- static const struct nla_policy
- udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
- [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
- [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
- };
- #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
- #ifdef CONFIG_SYSCTL
- static struct ctl_table udp_sysctl_table[] = {
- {
- .procname = "nf_conntrack_udp_timeout",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- {
- .procname = "nf_conntrack_udp_timeout_stream",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- { }
- };
- #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
- static struct ctl_table udp_compat_sysctl_table[] = {
- {
- .procname = "ip_conntrack_udp_timeout",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- {
- .procname = "ip_conntrack_udp_timeout_stream",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- { }
- };
- #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
- #endif /* CONFIG_SYSCTL */
- static int udp_kmemdup_sysctl_table(struct nf_proto_net *pn,
- struct nf_udp_net *un)
- {
- #ifdef CONFIG_SYSCTL
- if (pn->ctl_table)
- return 0;
- pn->ctl_table = kmemdup(udp_sysctl_table,
- sizeof(udp_sysctl_table),
- GFP_KERNEL);
- if (!pn->ctl_table)
- return -ENOMEM;
- pn->ctl_table[0].data = &un->timeouts[UDP_CT_UNREPLIED];
- pn->ctl_table[1].data = &un->timeouts[UDP_CT_REPLIED];
- #endif
- return 0;
- }
- static int udp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn,
- struct nf_udp_net *un)
- {
- #ifdef CONFIG_SYSCTL
- #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
- pn->ctl_compat_table = kmemdup(udp_compat_sysctl_table,
- sizeof(udp_compat_sysctl_table),
- GFP_KERNEL);
- if (!pn->ctl_compat_table)
- return -ENOMEM;
- pn->ctl_compat_table[0].data = &un->timeouts[UDP_CT_UNREPLIED];
- pn->ctl_compat_table[1].data = &un->timeouts[UDP_CT_REPLIED];
- #endif
- #endif
- return 0;
- }
- static int udp_init_net(struct net *net, u_int16_t proto)
- {
- int ret;
- struct nf_udp_net *un = udp_pernet(net);
- struct nf_proto_net *pn = &un->pn;
- if (!pn->users) {
- int i;
- for (i = 0; i < UDP_CT_MAX; i++)
- un->timeouts[i] = udp_timeouts[i];
- }
- if (proto == AF_INET) {
- ret = udp_kmemdup_compat_sysctl_table(pn, un);
- if (ret < 0)
- return ret;
- ret = udp_kmemdup_sysctl_table(pn, un);
- if (ret < 0)
- nf_ct_kfree_compat_sysctl_table(pn);
- } else
- ret = udp_kmemdup_sysctl_table(pn, un);
- return ret;
- }
- static struct nf_proto_net *udp_get_net_proto(struct net *net)
- {
- return &net->ct.nf_ct_proto.udp.pn;
- }
- struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
- {
- .l3proto = PF_INET,
- .l4proto = IPPROTO_UDP,
- .name = "udp",
- .pkt_to_tuple = udp_pkt_to_tuple,
- .invert_tuple = udp_invert_tuple,
- .print_tuple = udp_print_tuple,
- .packet = udp_packet,
- .get_timeouts = udp_get_timeouts,
- .new = udp_new,
- .error = udp_error,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
- .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
- .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
- .nla_policy = nf_ct_port_nla_policy,
- #endif
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
- .ctnl_timeout = {
- .nlattr_to_obj = udp_timeout_nlattr_to_obj,
- .obj_to_nlattr = udp_timeout_obj_to_nlattr,
- .nlattr_max = CTA_TIMEOUT_UDP_MAX,
- .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
- .nla_policy = udp_timeout_nla_policy,
- },
- #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
- .init_net = udp_init_net,
- .get_net_proto = udp_get_net_proto,
- };
- EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
- struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
- {
- .l3proto = PF_INET6,
- .l4proto = IPPROTO_UDP,
- .name = "udp",
- .pkt_to_tuple = udp_pkt_to_tuple,
- .invert_tuple = udp_invert_tuple,
- .print_tuple = udp_print_tuple,
- .packet = udp_packet,
- .get_timeouts = udp_get_timeouts,
- .new = udp_new,
- .error = udp_error,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
- .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
- .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
- .nla_policy = nf_ct_port_nla_policy,
- #endif
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
- .ctnl_timeout = {
- .nlattr_to_obj = udp_timeout_nlattr_to_obj,
- .obj_to_nlattr = udp_timeout_obj_to_nlattr,
- .nlattr_max = CTA_TIMEOUT_UDP_MAX,
- .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
- .nla_policy = udp_timeout_nla_policy,
- },
- #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
- .init_net = udp_init_net,
- .get_net_proto = udp_get_net_proto,
- };
- EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);
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