diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_proto_udp.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_udp.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c new file mode 100644 index 0000000..7c2ca48 --- /dev/null +++ b/net/netfilter/nf_conntrack_proto_udp.c @@ -0,0 +1,231 @@ +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> + * + * 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> + +static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ; +static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ; + +static bool udp_pkt_to_tuple(const struct sk_buff *skb, + unsigned int dataoff, + 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 int udp_print_tuple(struct seq_file *s, + const struct nf_conntrack_tuple *tuple) +{ + return seq_printf(s, "sport=%hu dport=%hu ", + ntohs(tuple->src.u.udp.port), + ntohs(tuple->dst.u.udp.port)); +} + +/* 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) +{ + /* 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, nf_ct_udp_timeout_stream); + /* 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_STATUS, ct); + } else + nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udp_timeout); + + 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) +{ + return true; +} + +static int udp_error(struct net *net, 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(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(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(pf, 0, skb, NULL, NULL, NULL, + "nf_ct_udp: bad UDP checksum "); + return -NF_ACCEPT; + } + + return NF_ACCEPT; +} + +#ifdef CONFIG_SYSCTL +static unsigned int udp_sysctl_table_users; +static struct ctl_table_header *udp_sysctl_header; +static struct ctl_table udp_sysctl_table[] = { + { + .procname = "nf_conntrack_udp_timeout", + .data = &nf_ct_udp_timeout, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec_jiffies, + }, + { + .procname = "nf_conntrack_udp_timeout_stream", + .data = &nf_ct_udp_timeout_stream, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec_jiffies, + }, + { + .ctl_name = 0 + } +}; +#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT +static struct ctl_table udp_compat_sysctl_table[] = { + { + .procname = "ip_conntrack_udp_timeout", + .data = &nf_ct_udp_timeout, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec_jiffies, + }, + { + .procname = "ip_conntrack_udp_timeout_stream", + .data = &nf_ct_udp_timeout_stream, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec_jiffies, + }, + { + .ctl_name = 0 + } +}; +#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ +#endif /* CONFIG_SYSCTL */ + +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, + .new = udp_new, + .error = udp_error, +#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) + .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, + .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, + .nla_policy = nf_ct_port_nla_policy, +#endif +#ifdef CONFIG_SYSCTL + .ctl_table_users = &udp_sysctl_table_users, + .ctl_table_header = &udp_sysctl_header, + .ctl_table = udp_sysctl_table, +#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT + .ctl_compat_table = udp_compat_sysctl_table, +#endif +#endif +}; +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, + .new = udp_new, + .error = udp_error, +#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) + .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, + .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, + .nla_policy = nf_ct_port_nla_policy, +#endif +#ifdef CONFIG_SYSCTL + .ctl_table_users = &udp_sysctl_table_users, + .ctl_table_header = &udp_sysctl_header, + .ctl_table = udp_sysctl_table, +#endif +}; +EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6); |
