1 // SPDX-License-Identifier: GPL-2.0-only
2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
7 #include <linux/types.h>
8 #include <linux/timer.h>
9 #include <linux/module.h>
10 #include <linux/udp.h>
11 #include <linux/seq_file.h>
12 #include <linux/skbuff.h>
13 #include <linux/ipv6.h>
14 #include <net/ip6_checksum.h>
15 #include <net/checksum.h>
17 #include <linux/netfilter.h>
18 #include <linux/netfilter_ipv4.h>
19 #include <linux/netfilter_ipv6.h>
20 #include <net/netfilter/nf_conntrack_l4proto.h>
21 #include <net/netfilter/nf_conntrack_ecache.h>
22 #include <net/netfilter/nf_conntrack_timeout.h>
23 #include <net/netfilter/nf_log.h>
24 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
25 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
27 static const unsigned int udp_timeouts[UDP_CT_MAX] = {
28 [UDP_CT_UNREPLIED] = 30*HZ,
29 [UDP_CT_REPLIED] = 120*HZ,
32 static unsigned int *udp_get_timeouts(struct net *net)
34 return nf_udp_pernet(net)->timeouts;
37 static void udp_error_log(const struct sk_buff *skb,
38 const struct nf_hook_state *state,
41 nf_l4proto_log_invalid(skb, state->net, state->pf,
42 IPPROTO_UDP, "%s", msg);
45 static bool udp_error(struct sk_buff *skb,
47 const struct nf_hook_state *state)
49 unsigned int udplen = skb->len - dataoff;
50 const struct udphdr *hdr;
53 /* Header is too small? */
54 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
56 udp_error_log(skb, state, "short packet");
60 /* Truncated/malformed packets */
61 if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
62 udp_error_log(skb, state, "truncated/malformed packet");
66 /* Packet with no checksum */
70 /* Checksum invalid? Ignore.
71 * We skip checking packets on the outgoing path
72 * because the checksum is assumed to be correct.
73 * FIXME: Source route IP option packets --RR */
74 if (state->hook == NF_INET_PRE_ROUTING &&
75 state->net->ct.sysctl_checksum &&
76 nf_checksum(skb, state->hook, dataoff, IPPROTO_UDP, state->pf)) {
77 udp_error_log(skb, state, "bad checksum");
84 static void nf_conntrack_udp_refresh_unreplied(struct nf_conn *ct,
86 enum ip_conntrack_info ctinfo,
89 if (unlikely(ctinfo == IP_CT_ESTABLISHED_REPLY &&
90 ct->status & IPS_NAT_CLASH))
93 nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies);
96 /* Returns verdict for packet, and may modify conntracktype */
97 int nf_conntrack_udp_packet(struct nf_conn *ct,
100 enum ip_conntrack_info ctinfo,
101 const struct nf_hook_state *state)
103 unsigned int *timeouts;
105 if (udp_error(skb, dataoff, state))
108 timeouts = nf_ct_timeout_lookup(ct);
110 timeouts = udp_get_timeouts(nf_ct_net(ct));
112 if (!nf_ct_is_confirmed(ct))
113 ct->proto.udp.stream_ts = 2 * HZ + jiffies;
115 /* If we've seen traffic both ways, this is some kind of UDP
116 * stream. Set Assured.
118 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
119 unsigned long extra = timeouts[UDP_CT_UNREPLIED];
121 /* Still active after two seconds? Extend timeout. */
122 if (time_after(jiffies, ct->proto.udp.stream_ts))
123 extra = timeouts[UDP_CT_REPLIED];
125 nf_ct_refresh_acct(ct, ctinfo, skb, extra);
127 /* Also, more likely to be important, and not a probe */
128 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
129 nf_conntrack_event_cache(IPCT_ASSURED, ct);
131 nf_conntrack_udp_refresh_unreplied(ct, skb, ctinfo,
132 timeouts[UDP_CT_UNREPLIED]);
137 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
138 static void udplite_error_log(const struct sk_buff *skb,
139 const struct nf_hook_state *state,
142 nf_l4proto_log_invalid(skb, state->net, state->pf,
143 IPPROTO_UDPLITE, "%s", msg);
146 static bool udplite_error(struct sk_buff *skb,
147 unsigned int dataoff,
148 const struct nf_hook_state *state)
150 unsigned int udplen = skb->len - dataoff;
151 const struct udphdr *hdr;
155 /* Header is too small? */
156 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
158 udplite_error_log(skb, state, "short packet");
162 cscov = ntohs(hdr->len);
165 } else if (cscov < sizeof(*hdr) || cscov > udplen) {
166 udplite_error_log(skb, state, "invalid checksum coverage");
170 /* UDPLITE mandates checksums */
172 udplite_error_log(skb, state, "checksum missing");
176 /* Checksum invalid? Ignore. */
177 if (state->hook == NF_INET_PRE_ROUTING &&
178 state->net->ct.sysctl_checksum &&
179 nf_checksum_partial(skb, state->hook, dataoff, cscov, IPPROTO_UDP,
181 udplite_error_log(skb, state, "bad checksum");
188 /* Returns verdict for packet, and may modify conntracktype */
189 int nf_conntrack_udplite_packet(struct nf_conn *ct,
191 unsigned int dataoff,
192 enum ip_conntrack_info ctinfo,
193 const struct nf_hook_state *state)
195 unsigned int *timeouts;
197 if (udplite_error(skb, dataoff, state))
200 timeouts = nf_ct_timeout_lookup(ct);
202 timeouts = udp_get_timeouts(nf_ct_net(ct));
204 /* If we've seen traffic both ways, this is some kind of UDP
205 stream. Extend timeout. */
206 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
207 nf_ct_refresh_acct(ct, ctinfo, skb,
208 timeouts[UDP_CT_REPLIED]);
209 /* Also, more likely to be important, and not a probe */
210 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
211 nf_conntrack_event_cache(IPCT_ASSURED, ct);
213 nf_conntrack_udp_refresh_unreplied(ct, skb, ctinfo,
214 timeouts[UDP_CT_UNREPLIED]);
220 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
222 #include <linux/netfilter/nfnetlink.h>
223 #include <linux/netfilter/nfnetlink_cttimeout.h>
225 static int udp_timeout_nlattr_to_obj(struct nlattr *tb[],
226 struct net *net, void *data)
228 unsigned int *timeouts = data;
229 struct nf_udp_net *un = nf_udp_pernet(net);
232 timeouts = un->timeouts;
234 /* set default timeouts for UDP. */
235 timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED];
236 timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED];
238 if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
239 timeouts[UDP_CT_UNREPLIED] =
240 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
242 if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
243 timeouts[UDP_CT_REPLIED] =
244 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
250 udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
252 const unsigned int *timeouts = data;
254 if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
255 htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) ||
256 nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED,
257 htonl(timeouts[UDP_CT_REPLIED] / HZ)))
258 goto nla_put_failure;
265 static const struct nla_policy
266 udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
267 [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
268 [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
270 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
272 void nf_conntrack_udp_init_net(struct net *net)
274 struct nf_udp_net *un = nf_udp_pernet(net);
277 for (i = 0; i < UDP_CT_MAX; i++)
278 un->timeouts[i] = udp_timeouts[i];
281 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udp =
283 .l4proto = IPPROTO_UDP,
285 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
286 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
287 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
288 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
289 .nla_policy = nf_ct_port_nla_policy,
291 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
293 .nlattr_to_obj = udp_timeout_nlattr_to_obj,
294 .obj_to_nlattr = udp_timeout_obj_to_nlattr,
295 .nlattr_max = CTA_TIMEOUT_UDP_MAX,
296 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
297 .nla_policy = udp_timeout_nla_policy,
299 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
302 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
303 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite =
305 .l4proto = IPPROTO_UDPLITE,
307 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
308 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
309 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
310 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
311 .nla_policy = nf_ct_port_nla_policy,
313 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
315 .nlattr_to_obj = udp_timeout_nlattr_to_obj,
316 .obj_to_nlattr = udp_timeout_obj_to_nlattr,
317 .nlattr_max = CTA_TIMEOUT_UDP_MAX,
318 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
319 .nla_policy = udp_timeout_nla_policy,
321 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */