| /* (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(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(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 (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING && |
| nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) { |
| if (LOG_INVALID(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); |