| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
| * |
| * 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. |
| */ |
| |
| #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]; |
| |
| /* Still active after two seconds? Extend timeout. */ |
| if (time_after(jiffies, ct->proto.udp.stream_ts)) |
| extra = timeouts[UDP_CT_REPLIED]; |
| |
| nf_ct_refresh_acct(ct, ctinfo, skb, extra); |
| |
| /* 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; |
| } |
| |
| #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]); |
| /* 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 |