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- // SPDX-License-Identifier: GPL-2.0-only
- /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
- */
- #include <linux/types.h>
- #include <linux/timer.h>
- #include <linux/module.h>
- #include <linux/udp.h>
- #include <linux/seq_file.h>
- #include <linux/skbuff.h>
- #include <linux/ipv6.h>
- #include <net/ip6_checksum.h>
- #include <net/checksum.h>
- #include <linux/netfilter.h>
- #include <linux/netfilter_ipv4.h>
- #include <linux/netfilter_ipv6.h>
- #include <net/netfilter/nf_conntrack_l4proto.h>
- #include <net/netfilter/nf_conntrack_ecache.h>
- #include <net/netfilter/nf_conntrack_timeout.h>
- #include <net/netfilter/nf_log.h>
- #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
- #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
- static const unsigned int udp_timeouts[UDP_CT_MAX] = {
- [UDP_CT_UNREPLIED] = 30*HZ,
- [UDP_CT_REPLIED] = 120*HZ,
- };
- static unsigned int *udp_get_timeouts(struct net *net)
- {
- return nf_udp_pernet(net)->timeouts;
- }
- static void udp_error_log(const struct sk_buff *skb,
- const struct nf_hook_state *state,
- const char *msg)
- {
- nf_l4proto_log_invalid(skb, state->net, state->pf,
- IPPROTO_UDP, "%s", msg);
- }
- static bool udp_error(struct sk_buff *skb,
- unsigned int dataoff,
- const struct nf_hook_state *state)
- {
- 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) {
- udp_error_log(skb, state, "short packet");
- return true;
- }
- /* Truncated/malformed packets */
- if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
- udp_error_log(skb, state, "truncated/malformed packet");
- return true;
- }
- /* Packet with no checksum */
- if (!hdr->check)
- return false;
- /* 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 (state->hook == NF_INET_PRE_ROUTING &&
- state->net->ct.sysctl_checksum &&
- nf_checksum(skb, state->hook, dataoff, IPPROTO_UDP, state->pf)) {
- udp_error_log(skb, state, "bad checksum");
- return true;
- }
- return false;
- }
- /* Returns verdict for packet, and may modify conntracktype */
- int nf_conntrack_udp_packet(struct nf_conn *ct,
- struct sk_buff *skb,
- unsigned int dataoff,
- enum ip_conntrack_info ctinfo,
- const struct nf_hook_state *state)
- {
- unsigned int *timeouts;
- if (udp_error(skb, dataoff, state))
- return -NF_ACCEPT;
- timeouts = nf_ct_timeout_lookup(ct);
- if (!timeouts)
- timeouts = udp_get_timeouts(nf_ct_net(ct));
- if (!nf_ct_is_confirmed(ct))
- ct->proto.udp.stream_ts = 2 * HZ + jiffies;
- /* If we've seen traffic both ways, this is some kind of UDP
- * stream. Set Assured.
- */
- if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
- unsigned long extra = timeouts[UDP_CT_UNREPLIED];
- bool stream = false;
- /* Still active after two seconds? Extend timeout. */
- if (time_after(jiffies, ct->proto.udp.stream_ts)) {
- extra = timeouts[UDP_CT_REPLIED];
- stream = true;
- }
- nf_ct_refresh_acct(ct, ctinfo, skb, extra);
- /* never set ASSURED for IPS_NAT_CLASH, they time out soon */
- if (unlikely((ct->status & IPS_NAT_CLASH)))
- return NF_ACCEPT;
- /* Also, more likely to be important, and not a probe */
- if (stream && !test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
- nf_conntrack_event_cache(IPCT_ASSURED, ct);
- } else {
- nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[UDP_CT_UNREPLIED]);
- }
- return NF_ACCEPT;
- }
- #ifdef CONFIG_NF_CT_PROTO_UDPLITE
- static void udplite_error_log(const struct sk_buff *skb,
- const struct nf_hook_state *state,
- const char *msg)
- {
- nf_l4proto_log_invalid(skb, state->net, state->pf,
- IPPROTO_UDPLITE, "%s", msg);
- }
- static bool udplite_error(struct sk_buff *skb,
- unsigned int dataoff,
- const struct nf_hook_state *state)
- {
- unsigned int udplen = skb->len - dataoff;
- const struct udphdr *hdr;
- struct udphdr _hdr;
- unsigned int cscov;
- /* Header is too small? */
- hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
- if (!hdr) {
- udplite_error_log(skb, state, "short packet");
- return true;
- }
- cscov = ntohs(hdr->len);
- if (cscov == 0) {
- cscov = udplen;
- } else if (cscov < sizeof(*hdr) || cscov > udplen) {
- udplite_error_log(skb, state, "invalid checksum coverage");
- return true;
- }
- /* UDPLITE mandates checksums */
- if (!hdr->check) {
- udplite_error_log(skb, state, "checksum missing");
- return true;
- }
- /* Checksum invalid? Ignore. */
- if (state->hook == NF_INET_PRE_ROUTING &&
- state->net->ct.sysctl_checksum &&
- nf_checksum_partial(skb, state->hook, dataoff, cscov, IPPROTO_UDP,
- state->pf)) {
- udplite_error_log(skb, state, "bad checksum");
- return true;
- }
- return false;
- }
- /* Returns verdict for packet, and may modify conntracktype */
- int nf_conntrack_udplite_packet(struct nf_conn *ct,
- struct sk_buff *skb,
- unsigned int dataoff,
- enum ip_conntrack_info ctinfo,
- const struct nf_hook_state *state)
- {
- unsigned int *timeouts;
- if (udplite_error(skb, dataoff, state))
- return -NF_ACCEPT;
- timeouts = nf_ct_timeout_lookup(ct);
- if (!timeouts)
- timeouts = udp_get_timeouts(nf_ct_net(ct));
- /* 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,
- timeouts[UDP_CT_REPLIED]);
- if (unlikely((ct->status & IPS_NAT_CLASH)))
- return NF_ACCEPT;
- /* 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_ASSURED, ct);
- } else {
- nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[UDP_CT_UNREPLIED]);
- }
- return NF_ACCEPT;
- }
- #endif
- #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
- #include <linux/netfilter/nfnetlink.h>
- #include <linux/netfilter/nfnetlink_cttimeout.h>
- static int udp_timeout_nlattr_to_obj(struct nlattr *tb[],
- struct net *net, void *data)
- {
- unsigned int *timeouts = data;
- struct nf_udp_net *un = nf_udp_pernet(net);
- if (!timeouts)
- timeouts = un->timeouts;
- /* set default timeouts for UDP. */
- timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED];
- timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED];
- if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
- timeouts[UDP_CT_UNREPLIED] =
- ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
- }
- if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
- timeouts[UDP_CT_REPLIED] =
- ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
- }
- return 0;
- }
- static int
- udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
- {
- const unsigned int *timeouts = data;
- if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
- htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) ||
- nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED,
- htonl(timeouts[UDP_CT_REPLIED] / HZ)))
- goto nla_put_failure;
- return 0;
- nla_put_failure:
- return -ENOSPC;
- }
- static const struct nla_policy
- udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
- [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
- [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
- };
- #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
- void nf_conntrack_udp_init_net(struct net *net)
- {
- struct nf_udp_net *un = nf_udp_pernet(net);
- int i;
- for (i = 0; i < UDP_CT_MAX; i++)
- un->timeouts[i] = udp_timeouts[i];
- }
- const struct nf_conntrack_l4proto nf_conntrack_l4proto_udp =
- {
- .l4proto = IPPROTO_UDP,
- .allow_clash = true,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .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_NF_CONNTRACK_TIMEOUT
- .ctnl_timeout = {
- .nlattr_to_obj = udp_timeout_nlattr_to_obj,
- .obj_to_nlattr = udp_timeout_obj_to_nlattr,
- .nlattr_max = CTA_TIMEOUT_UDP_MAX,
- .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
- .nla_policy = udp_timeout_nla_policy,
- },
- #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
- };
- #ifdef CONFIG_NF_CT_PROTO_UDPLITE
- const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite =
- {
- .l4proto = IPPROTO_UDPLITE,
- .allow_clash = true,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .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_NF_CONNTRACK_TIMEOUT
- .ctnl_timeout = {
- .nlattr_to_obj = udp_timeout_nlattr_to_obj,
- .obj_to_nlattr = udp_timeout_obj_to_nlattr,
- .nlattr_max = CTA_TIMEOUT_UDP_MAX,
- .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
- .nla_policy = udp_timeout_nla_policy,
- },
- #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
- };
- #endif
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