| 1 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 2 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 3 | * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/timer.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/udp.h> |
| 14 | #include <linux/seq_file.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/ipv6.h> |
| 17 | #include <net/ip6_checksum.h> |
| 18 | #include <net/checksum.h> |
| 19 | |
| 20 | #include <linux/netfilter.h> |
| 21 | #include <linux/netfilter_ipv4.h> |
| 22 | #include <linux/netfilter_ipv6.h> |
| 23 | #include <net/netfilter/nf_conntrack_l4proto.h> |
| 24 | #include <net/netfilter/nf_conntrack_ecache.h> |
| 25 | #include <net/netfilter/nf_log.h> |
| 26 | #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> |
| 27 | #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> |
| 28 | |
| 29 | static unsigned int udp_timeouts[UDP_CT_MAX] = { |
| 30 | [UDP_CT_UNREPLIED] = 30*HZ, |
| 31 | [UDP_CT_REPLIED] = 180*HZ, |
| 32 | }; |
| 33 | |
| 34 | static inline struct nf_udp_net *udp_pernet(struct net *net) |
| 35 | { |
| 36 | return &net->ct.nf_ct_proto.udp; |
| 37 | } |
| 38 | |
| 39 | static bool udp_pkt_to_tuple(const struct sk_buff *skb, |
| 40 | unsigned int dataoff, |
| 41 | struct net *net, |
| 42 | struct nf_conntrack_tuple *tuple) |
| 43 | { |
| 44 | const struct udphdr *hp; |
| 45 | struct udphdr _hdr; |
| 46 | |
| 47 | /* Actually only need first 8 bytes. */ |
| 48 | hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
| 49 | if (hp == NULL) |
| 50 | return false; |
| 51 | |
| 52 | tuple->src.u.udp.port = hp->source; |
| 53 | tuple->dst.u.udp.port = hp->dest; |
| 54 | |
| 55 | return true; |
| 56 | } |
| 57 | |
| 58 | static bool udp_invert_tuple(struct nf_conntrack_tuple *tuple, |
| 59 | const struct nf_conntrack_tuple *orig) |
| 60 | { |
| 61 | tuple->src.u.udp.port = orig->dst.u.udp.port; |
| 62 | tuple->dst.u.udp.port = orig->src.u.udp.port; |
| 63 | return true; |
| 64 | } |
| 65 | |
| 66 | /* Print out the per-protocol part of the tuple. */ |
| 67 | static void udp_print_tuple(struct seq_file *s, |
| 68 | const struct nf_conntrack_tuple *tuple) |
| 69 | { |
| 70 | seq_printf(s, "sport=%hu dport=%hu ", |
| 71 | ntohs(tuple->src.u.udp.port), |
| 72 | ntohs(tuple->dst.u.udp.port)); |
| 73 | } |
| 74 | |
| 75 | static unsigned int *udp_get_timeouts(struct net *net) |
| 76 | { |
| 77 | return udp_pernet(net)->timeouts; |
| 78 | } |
| 79 | |
| 80 | /* Returns verdict for packet, and may modify conntracktype */ |
| 81 | static int udp_packet(struct nf_conn *ct, |
| 82 | const struct sk_buff *skb, |
| 83 | unsigned int dataoff, |
| 84 | enum ip_conntrack_info ctinfo, |
| 85 | u_int8_t pf, |
| 86 | unsigned int hooknum, |
| 87 | unsigned int *timeouts) |
| 88 | { |
| 89 | /* If we've seen traffic both ways, this is some kind of UDP |
| 90 | stream. Extend timeout. */ |
| 91 | if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
| 92 | nf_ct_refresh_acct(ct, ctinfo, skb, |
| 93 | timeouts[UDP_CT_REPLIED]); |
| 94 | /* Also, more likely to be important, and not a probe */ |
| 95 | if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) |
| 96 | nf_conntrack_event_cache(IPCT_ASSURED, ct); |
| 97 | } else { |
| 98 | nf_ct_refresh_acct(ct, ctinfo, skb, |
| 99 | timeouts[UDP_CT_UNREPLIED]); |
| 100 | } |
| 101 | return NF_ACCEPT; |
| 102 | } |
| 103 | |
| 104 | /* Called when a new connection for this protocol found. */ |
| 105 | static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb, |
| 106 | unsigned int dataoff, unsigned int *timeouts) |
| 107 | { |
| 108 | return true; |
| 109 | } |
| 110 | |
| 111 | static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb, |
| 112 | unsigned int dataoff, enum ip_conntrack_info *ctinfo, |
| 113 | u_int8_t pf, |
| 114 | unsigned int hooknum) |
| 115 | { |
| 116 | unsigned int udplen = skb->len - dataoff; |
| 117 | const struct udphdr *hdr; |
| 118 | struct udphdr _hdr; |
| 119 | |
| 120 | /* Header is too small? */ |
| 121 | hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
| 122 | if (hdr == NULL) { |
| 123 | if (LOG_INVALID(net, IPPROTO_UDP)) |
| 124 | nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, |
| 125 | "nf_ct_udp: short packet "); |
| 126 | return -NF_ACCEPT; |
| 127 | } |
| 128 | |
| 129 | /* Truncated/malformed packets */ |
| 130 | if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) { |
| 131 | if (LOG_INVALID(net, IPPROTO_UDP)) |
| 132 | nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, |
| 133 | "nf_ct_udp: truncated/malformed packet "); |
| 134 | return -NF_ACCEPT; |
| 135 | } |
| 136 | |
| 137 | /* Packet with no checksum */ |
| 138 | if (!hdr->check) |
| 139 | return NF_ACCEPT; |
| 140 | |
| 141 | /* Checksum invalid? Ignore. |
| 142 | * We skip checking packets on the outgoing path |
| 143 | * because the checksum is assumed to be correct. |
| 144 | * FIXME: Source route IP option packets --RR */ |
| 145 | if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && |
| 146 | nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) { |
| 147 | if (LOG_INVALID(net, IPPROTO_UDP)) |
| 148 | nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, |
| 149 | "nf_ct_udp: bad UDP checksum "); |
| 150 | return -NF_ACCEPT; |
| 151 | } |
| 152 | |
| 153 | return NF_ACCEPT; |
| 154 | } |
| 155 | |
| 156 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) |
| 157 | |
| 158 | #include <linux/netfilter/nfnetlink.h> |
| 159 | #include <linux/netfilter/nfnetlink_cttimeout.h> |
| 160 | |
| 161 | static int udp_timeout_nlattr_to_obj(struct nlattr *tb[], |
| 162 | struct net *net, void *data) |
| 163 | { |
| 164 | unsigned int *timeouts = data; |
| 165 | struct nf_udp_net *un = udp_pernet(net); |
| 166 | |
| 167 | /* set default timeouts for UDP. */ |
| 168 | timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED]; |
| 169 | timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED]; |
| 170 | |
| 171 | if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) { |
| 172 | timeouts[UDP_CT_UNREPLIED] = |
| 173 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ; |
| 174 | } |
| 175 | if (tb[CTA_TIMEOUT_UDP_REPLIED]) { |
| 176 | timeouts[UDP_CT_REPLIED] = |
| 177 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ; |
| 178 | } |
| 179 | return 0; |
| 180 | } |
| 181 | |
| 182 | static int |
| 183 | udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) |
| 184 | { |
| 185 | const unsigned int *timeouts = data; |
| 186 | |
| 187 | if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED, |
| 188 | htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) || |
| 189 | nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED, |
| 190 | htonl(timeouts[UDP_CT_REPLIED] / HZ))) |
| 191 | goto nla_put_failure; |
| 192 | return 0; |
| 193 | |
| 194 | nla_put_failure: |
| 195 | return -ENOSPC; |
| 196 | } |
| 197 | |
| 198 | static const struct nla_policy |
| 199 | udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = { |
| 200 | [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 }, |
| 201 | [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 }, |
| 202 | }; |
| 203 | #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ |
| 204 | |
| 205 | #ifdef CONFIG_SYSCTL |
| 206 | static struct ctl_table udp_sysctl_table[] = { |
| 207 | { |
| 208 | .procname = "nf_conntrack_udp_timeout", |
| 209 | .maxlen = sizeof(unsigned int), |
| 210 | .mode = 0644, |
| 211 | .proc_handler = proc_dointvec_jiffies, |
| 212 | }, |
| 213 | { |
| 214 | .procname = "nf_conntrack_udp_timeout_stream", |
| 215 | .maxlen = sizeof(unsigned int), |
| 216 | .mode = 0644, |
| 217 | .proc_handler = proc_dointvec_jiffies, |
| 218 | }, |
| 219 | { } |
| 220 | }; |
| 221 | #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| 222 | static struct ctl_table udp_compat_sysctl_table[] = { |
| 223 | { |
| 224 | .procname = "ip_conntrack_udp_timeout", |
| 225 | .maxlen = sizeof(unsigned int), |
| 226 | .mode = 0644, |
| 227 | .proc_handler = proc_dointvec_jiffies, |
| 228 | }, |
| 229 | { |
| 230 | .procname = "ip_conntrack_udp_timeout_stream", |
| 231 | .maxlen = sizeof(unsigned int), |
| 232 | .mode = 0644, |
| 233 | .proc_handler = proc_dointvec_jiffies, |
| 234 | }, |
| 235 | { } |
| 236 | }; |
| 237 | #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| 238 | #endif /* CONFIG_SYSCTL */ |
| 239 | |
| 240 | static int udp_kmemdup_sysctl_table(struct nf_proto_net *pn, |
| 241 | struct nf_udp_net *un) |
| 242 | { |
| 243 | #ifdef CONFIG_SYSCTL |
| 244 | if (pn->ctl_table) |
| 245 | return 0; |
| 246 | pn->ctl_table = kmemdup(udp_sysctl_table, |
| 247 | sizeof(udp_sysctl_table), |
| 248 | GFP_KERNEL); |
| 249 | if (!pn->ctl_table) |
| 250 | return -ENOMEM; |
| 251 | pn->ctl_table[0].data = &un->timeouts[UDP_CT_UNREPLIED]; |
| 252 | pn->ctl_table[1].data = &un->timeouts[UDP_CT_REPLIED]; |
| 253 | #endif |
| 254 | return 0; |
| 255 | } |
| 256 | |
| 257 | static int udp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn, |
| 258 | struct nf_udp_net *un) |
| 259 | { |
| 260 | #ifdef CONFIG_SYSCTL |
| 261 | #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| 262 | pn->ctl_compat_table = kmemdup(udp_compat_sysctl_table, |
| 263 | sizeof(udp_compat_sysctl_table), |
| 264 | GFP_KERNEL); |
| 265 | if (!pn->ctl_compat_table) |
| 266 | return -ENOMEM; |
| 267 | |
| 268 | pn->ctl_compat_table[0].data = &un->timeouts[UDP_CT_UNREPLIED]; |
| 269 | pn->ctl_compat_table[1].data = &un->timeouts[UDP_CT_REPLIED]; |
| 270 | #endif |
| 271 | #endif |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | static int udp_init_net(struct net *net, u_int16_t proto) |
| 276 | { |
| 277 | int ret; |
| 278 | struct nf_udp_net *un = udp_pernet(net); |
| 279 | struct nf_proto_net *pn = &un->pn; |
| 280 | |
| 281 | if (!pn->users) { |
| 282 | int i; |
| 283 | |
| 284 | for (i = 0; i < UDP_CT_MAX; i++) |
| 285 | un->timeouts[i] = udp_timeouts[i]; |
| 286 | } |
| 287 | |
| 288 | if (proto == AF_INET) { |
| 289 | ret = udp_kmemdup_compat_sysctl_table(pn, un); |
| 290 | if (ret < 0) |
| 291 | return ret; |
| 292 | |
| 293 | ret = udp_kmemdup_sysctl_table(pn, un); |
| 294 | if (ret < 0) |
| 295 | nf_ct_kfree_compat_sysctl_table(pn); |
| 296 | } else |
| 297 | ret = udp_kmemdup_sysctl_table(pn, un); |
| 298 | |
| 299 | return ret; |
| 300 | } |
| 301 | |
| 302 | static struct nf_proto_net *udp_get_net_proto(struct net *net) |
| 303 | { |
| 304 | return &net->ct.nf_ct_proto.udp.pn; |
| 305 | } |
| 306 | |
| 307 | struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly = |
| 308 | { |
| 309 | .l3proto = PF_INET, |
| 310 | .l4proto = IPPROTO_UDP, |
| 311 | .name = "udp", |
| 312 | .allow_clash = true, |
| 313 | .pkt_to_tuple = udp_pkt_to_tuple, |
| 314 | .invert_tuple = udp_invert_tuple, |
| 315 | .print_tuple = udp_print_tuple, |
| 316 | .packet = udp_packet, |
| 317 | .get_timeouts = udp_get_timeouts, |
| 318 | .new = udp_new, |
| 319 | .error = udp_error, |
| 320 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| 321 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
| 322 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
| 323 | .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
| 324 | .nla_policy = nf_ct_port_nla_policy, |
| 325 | #endif |
| 326 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) |
| 327 | .ctnl_timeout = { |
| 328 | .nlattr_to_obj = udp_timeout_nlattr_to_obj, |
| 329 | .obj_to_nlattr = udp_timeout_obj_to_nlattr, |
| 330 | .nlattr_max = CTA_TIMEOUT_UDP_MAX, |
| 331 | .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, |
| 332 | .nla_policy = udp_timeout_nla_policy, |
| 333 | }, |
| 334 | #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ |
| 335 | .init_net = udp_init_net, |
| 336 | .get_net_proto = udp_get_net_proto, |
| 337 | }; |
| 338 | EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4); |
| 339 | |
| 340 | struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly = |
| 341 | { |
| 342 | .l3proto = PF_INET6, |
| 343 | .l4proto = IPPROTO_UDP, |
| 344 | .name = "udp", |
| 345 | .allow_clash = true, |
| 346 | .pkt_to_tuple = udp_pkt_to_tuple, |
| 347 | .invert_tuple = udp_invert_tuple, |
| 348 | .print_tuple = udp_print_tuple, |
| 349 | .packet = udp_packet, |
| 350 | .get_timeouts = udp_get_timeouts, |
| 351 | .new = udp_new, |
| 352 | .error = udp_error, |
| 353 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| 354 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
| 355 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
| 356 | .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
| 357 | .nla_policy = nf_ct_port_nla_policy, |
| 358 | #endif |
| 359 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) |
| 360 | .ctnl_timeout = { |
| 361 | .nlattr_to_obj = udp_timeout_nlattr_to_obj, |
| 362 | .obj_to_nlattr = udp_timeout_obj_to_nlattr, |
| 363 | .nlattr_max = CTA_TIMEOUT_UDP_MAX, |
| 364 | .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, |
| 365 | .nla_policy = udp_timeout_nla_policy, |
| 366 | }, |
| 367 | #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ |
| 368 | .init_net = udp_init_net, |
| 369 | .get_net_proto = udp_get_net_proto, |
| 370 | }; |
| 371 | EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6); |