Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 1 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 2 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> |
| 9 | * - enable working with Layer 3 protocol independent connection tracking. |
| 10 | * |
| 11 | * Derived from net/ipv4/netfilter/ip_conntrack_proto_udp.c |
| 12 | */ |
| 13 | |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/sched.h> |
| 16 | #include <linux/timer.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/netfilter.h> |
| 19 | #include <linux/udp.h> |
| 20 | #include <linux/seq_file.h> |
| 21 | #include <linux/skbuff.h> |
| 22 | #include <linux/ipv6.h> |
| 23 | #include <net/ip6_checksum.h> |
| 24 | #include <net/checksum.h> |
| 25 | #include <linux/netfilter.h> |
| 26 | #include <linux/netfilter_ipv4.h> |
| 27 | #include <linux/netfilter_ipv6.h> |
| 28 | #include <net/netfilter/nf_conntrack_protocol.h> |
| 29 | |
| 30 | unsigned long nf_ct_udp_timeout = 30*HZ; |
| 31 | unsigned long nf_ct_udp_timeout_stream = 180*HZ; |
| 32 | |
| 33 | static int udp_pkt_to_tuple(const struct sk_buff *skb, |
| 34 | unsigned int dataoff, |
| 35 | struct nf_conntrack_tuple *tuple) |
| 36 | { |
| 37 | struct udphdr _hdr, *hp; |
| 38 | |
| 39 | /* Actually only need first 8 bytes. */ |
| 40 | hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
| 41 | if (hp == NULL) |
| 42 | return 0; |
| 43 | |
| 44 | tuple->src.u.udp.port = hp->source; |
| 45 | tuple->dst.u.udp.port = hp->dest; |
| 46 | |
| 47 | return 1; |
| 48 | } |
| 49 | |
| 50 | static int udp_invert_tuple(struct nf_conntrack_tuple *tuple, |
| 51 | const struct nf_conntrack_tuple *orig) |
| 52 | { |
| 53 | tuple->src.u.udp.port = orig->dst.u.udp.port; |
| 54 | tuple->dst.u.udp.port = orig->src.u.udp.port; |
| 55 | return 1; |
| 56 | } |
| 57 | |
| 58 | /* Print out the per-protocol part of the tuple. */ |
| 59 | static int udp_print_tuple(struct seq_file *s, |
| 60 | const struct nf_conntrack_tuple *tuple) |
| 61 | { |
| 62 | return seq_printf(s, "sport=%hu dport=%hu ", |
| 63 | ntohs(tuple->src.u.udp.port), |
| 64 | ntohs(tuple->dst.u.udp.port)); |
| 65 | } |
| 66 | |
| 67 | /* Print out the private part of the conntrack. */ |
| 68 | static int udp_print_conntrack(struct seq_file *s, |
| 69 | const struct nf_conn *conntrack) |
| 70 | { |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | /* Returns verdict for packet, and may modify conntracktype */ |
| 75 | static int udp_packet(struct nf_conn *conntrack, |
| 76 | const struct sk_buff *skb, |
| 77 | unsigned int dataoff, |
| 78 | enum ip_conntrack_info ctinfo, |
| 79 | int pf, |
| 80 | unsigned int hooknum) |
| 81 | { |
| 82 | /* If we've seen traffic both ways, this is some kind of UDP |
| 83 | stream. Extend timeout. */ |
| 84 | if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) { |
| 85 | nf_ct_refresh_acct(conntrack, ctinfo, skb, |
| 86 | nf_ct_udp_timeout_stream); |
| 87 | /* Also, more likely to be important, and not a probe */ |
| 88 | if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status)) |
| 89 | nf_conntrack_event_cache(IPCT_STATUS, skb); |
| 90 | } else |
| 91 | nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout); |
| 92 | |
| 93 | return NF_ACCEPT; |
| 94 | } |
| 95 | |
| 96 | /* Called when a new connection for this protocol found. */ |
| 97 | static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb, |
| 98 | unsigned int dataoff) |
| 99 | { |
| 100 | return 1; |
| 101 | } |
| 102 | |
| 103 | static int udp_error(struct sk_buff *skb, unsigned int dataoff, |
| 104 | enum ip_conntrack_info *ctinfo, |
| 105 | int pf, |
| 106 | unsigned int hooknum, |
| 107 | int (*csum)(const struct sk_buff *, unsigned int)) |
| 108 | { |
| 109 | unsigned int udplen = skb->len - dataoff; |
| 110 | struct udphdr _hdr, *hdr; |
| 111 | |
| 112 | /* Header is too small? */ |
| 113 | hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
| 114 | if (hdr == NULL) { |
| 115 | if (LOG_INVALID(IPPROTO_UDP)) |
| 116 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| 117 | "nf_ct_udp: short packet "); |
| 118 | return -NF_ACCEPT; |
| 119 | } |
| 120 | |
| 121 | /* Truncated/malformed packets */ |
| 122 | if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) { |
| 123 | if (LOG_INVALID(IPPROTO_UDP)) |
| 124 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| 125 | "nf_ct_udp: truncated/malformed packet "); |
| 126 | return -NF_ACCEPT; |
| 127 | } |
| 128 | |
| 129 | /* Packet with no checksum */ |
| 130 | if (!hdr->check) |
| 131 | return NF_ACCEPT; |
| 132 | |
| 133 | /* Checksum invalid? Ignore. |
| 134 | * We skip checking packets on the outgoing path |
| 135 | * because the semantic of CHECKSUM_HW is different there |
| 136 | * and moreover root might send raw packets. |
| 137 | * FIXME: Source route IP option packets --RR */ |
| 138 | if (((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) || |
| 139 | (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) |
| 140 | && skb->ip_summed != CHECKSUM_UNNECESSARY |
| 141 | && csum(skb, dataoff)) { |
| 142 | if (LOG_INVALID(IPPROTO_UDP)) |
| 143 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| 144 | "nf_ct_udp: bad UDP checksum "); |
| 145 | return -NF_ACCEPT; |
| 146 | } |
| 147 | |
| 148 | return NF_ACCEPT; |
| 149 | } |
| 150 | |
| 151 | static int csum4(const struct sk_buff *skb, unsigned int dataoff) |
| 152 | { |
| 153 | return csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr, |
| 154 | skb->len - dataoff, IPPROTO_UDP, |
| 155 | skb->ip_summed == CHECKSUM_HW ? skb->csum |
| 156 | : skb_checksum(skb, dataoff, |
| 157 | skb->len - dataoff, 0)); |
| 158 | } |
| 159 | |
| 160 | static int csum6(const struct sk_buff *skb, unsigned int dataoff) |
| 161 | { |
| 162 | return csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr, |
| 163 | skb->len - dataoff, IPPROTO_UDP, |
| 164 | skb->ip_summed == CHECKSUM_HW ? skb->csum |
| 165 | : skb_checksum(skb, dataoff, skb->len - dataoff, |
| 166 | 0)); |
| 167 | } |
| 168 | |
| 169 | static int udp_error4(struct sk_buff *skb, |
| 170 | unsigned int dataoff, |
| 171 | enum ip_conntrack_info *ctinfo, |
| 172 | int pf, |
| 173 | unsigned int hooknum) |
| 174 | { |
| 175 | return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum4); |
| 176 | } |
| 177 | |
| 178 | static int udp_error6(struct sk_buff *skb, |
| 179 | unsigned int dataoff, |
| 180 | enum ip_conntrack_info *ctinfo, |
| 181 | int pf, |
| 182 | unsigned int hooknum) |
| 183 | { |
| 184 | return udp_error(skb, dataoff, ctinfo, pf, hooknum, csum6); |
| 185 | } |
| 186 | |
| 187 | struct nf_conntrack_protocol nf_conntrack_protocol_udp4 = |
| 188 | { |
| 189 | .l3proto = PF_INET, |
| 190 | .proto = IPPROTO_UDP, |
| 191 | .name = "udp", |
| 192 | .pkt_to_tuple = udp_pkt_to_tuple, |
| 193 | .invert_tuple = udp_invert_tuple, |
| 194 | .print_tuple = udp_print_tuple, |
| 195 | .print_conntrack = udp_print_conntrack, |
| 196 | .packet = udp_packet, |
| 197 | .new = udp_new, |
| 198 | .error = udp_error4, |
| 199 | }; |
| 200 | |
| 201 | struct nf_conntrack_protocol nf_conntrack_protocol_udp6 = |
| 202 | { |
| 203 | .l3proto = PF_INET6, |
| 204 | .proto = IPPROTO_UDP, |
| 205 | .name = "udp", |
| 206 | .pkt_to_tuple = udp_pkt_to_tuple, |
| 207 | .invert_tuple = udp_invert_tuple, |
| 208 | .print_tuple = udp_print_tuple, |
| 209 | .print_conntrack = udp_print_conntrack, |
| 210 | .packet = udp_packet, |
| 211 | .new = udp_new, |
| 212 | .error = udp_error6, |
| 213 | }; |
| 214 | |
| 215 | EXPORT_SYMBOL(nf_conntrack_protocol_udp4); |
| 216 | EXPORT_SYMBOL(nf_conntrack_protocol_udp6); |