/* (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. * * 16 Dec 2003: Yasuyuki Kozakai @USAGI * - enable working with Layer 3 protocol independent connection tracking. * * Derived from net/ipv4/netfilter/ip_conntrack_proto_udp.c */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include unsigned int nf_ct_udp_timeout = 30*HZ; unsigned int nf_ct_udp_timeout_stream = 180*HZ; static int udp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff, struct nf_conntrack_tuple *tuple) { struct udphdr _hdr, *hp; /* Actually only need first 8 bytes. */ hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); if (hp == NULL) return 0; tuple->src.u.udp.port = hp->source; tuple->dst.u.udp.port = hp->dest; return 1; } static int 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 1; } /* 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)); } /* Print out the private part of the conntrack. */ static int udp_print_conntrack(struct seq_file *s, const struct nf_conn *conntrack) { return 0; } /* Returns verdict for packet, and may modify conntracktype */ static int udp_packet(struct nf_conn *conntrack, const struct sk_buff *skb, unsigned int dataoff, enum ip_conntrack_info ctinfo, int 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, &conntrack->status)) { nf_ct_refresh_acct(conntrack, 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, &conntrack->status)) nf_conntrack_event_cache(IPCT_STATUS, skb); } else nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout); return NF_ACCEPT; } /* Called when a new connection for this protocol found. */ static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb, unsigned int dataoff) { return 1; } static int udp_error(struct sk_buff *skb, unsigned int dataoff, enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum, int (*csum)(const struct sk_buff *, unsigned int)) { unsigned int udplen = skb->len - dataoff; struct udphdr _hdr, *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 semantic of CHECKSUM_HW is different there * and moreover root might send raw packets. * FIXME: Source route IP option packets --RR */ if (((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) || (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) && skb->ip_summed != CHECKSUM_UNNECESSARY && csum(skb, dataoff)) { 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; } static int csum4(const struct sk_buff *skb, unsigned int dataoff) { return csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr, skb->len - dataoff, IPPROTO_UDP, skb->ip_summed == CHECKSUM_HW ? skb->csum : skb_checksum(skb, dataoff, skb->len - dataoff, 0)); } static int csum6(const struct sk_buff *skb, unsigned int dataoff) { return csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr, skb->len - dataoff, IPPROTO_UDP, skb->ip_summed == CHECKSUM_HW ? csum_sub(skb->csum, skb_checksum(skb, 0, dataoff, 0)) : skb_checksum(skb, dataoff, skb->len - dataoff, 0)); } static int udp_error4(struct sk_buff *skb, unsigned int dataoff, enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum) { return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum4); } static int udp_error6(struct sk_buff *skb, unsigned int dataoff, enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum) { return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum6); } struct nf_conntrack_protocol nf_conntrack_protocol_udp4 = { .l3proto = PF_INET, .proto = IPPROTO_UDP, .name = "udp", .pkt_to_tuple = udp_pkt_to_tuple, .invert_tuple = udp_invert_tuple, .print_tuple = udp_print_tuple, .print_conntrack = udp_print_conntrack, .packet = udp_packet, .new = udp_new, .error = udp_error4, #if defined(CONFIG_NF_CT_NETLINK) || \ defined(CONFIG_NF_CT_NETLINK_MODULE) .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr, .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple, #endif }; struct nf_conntrack_protocol nf_conntrack_protocol_udp6 = { .l3proto = PF_INET6, .proto = IPPROTO_UDP, .name = "udp", .pkt_to_tuple = udp_pkt_to_tuple, .invert_tuple = udp_invert_tuple, .print_tuple = udp_print_tuple, .print_conntrack = udp_print_conntrack, .packet = udp_packet, .new = udp_new, .error = udp_error6, #if defined(CONFIG_NF_CT_NETLINK) || \ defined(CONFIG_NF_CT_NETLINK_MODULE) .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr, .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple, #endif }; EXPORT_SYMBOL(nf_conntrack_protocol_udp4); EXPORT_SYMBOL(nf_conntrack_protocol_udp6);