/* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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, .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, .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, .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, .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);