diff options
| -rw-r--r-- | include/net/netfilter/nf_conntrack_synproxy.h | 13 | ||||
| -rw-r--r-- | include/net/netfilter/nf_synproxy.h | 44 | ||||
| -rw-r--r-- | net/ipv4/netfilter/ipt_SYNPROXY.c | 394 | ||||
| -rw-r--r-- | net/ipv6/netfilter/ip6t_SYNPROXY.c | 420 | ||||
| -rw-r--r-- | net/netfilter/nf_synproxy_core.c | 896 |
5 files changed, 920 insertions, 847 deletions
diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h index 2c7559a54092..c5659dcf5b1a 100644 --- a/include/net/netfilter/nf_conntrack_synproxy.h +++ b/include/net/netfilter/nf_conntrack_synproxy.h @@ -72,21 +72,12 @@ struct synproxy_options { }; struct tcphdr; -struct xt_synproxy_info; +struct nf_synproxy_info; bool synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, const struct tcphdr *th, struct synproxy_options *opts); -unsigned int synproxy_options_size(const struct synproxy_options *opts); -void synproxy_build_options(struct tcphdr *th, - const struct synproxy_options *opts); -void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info, +void synproxy_init_timestamp_cookie(const struct nf_synproxy_info *info, struct synproxy_options *opts); -void synproxy_check_timestamp_cookie(struct synproxy_options *opts); - -unsigned int synproxy_tstamp_adjust(struct sk_buff *skb, unsigned int protoff, - struct tcphdr *th, struct nf_conn *ct, - enum ip_conntrack_info ctinfo, - const struct nf_conn_synproxy *synproxy); #endif /* _NF_CONNTRACK_SYNPROXY_H */ diff --git a/include/net/netfilter/nf_synproxy.h b/include/net/netfilter/nf_synproxy.h new file mode 100644 index 000000000000..3e8b3f03b687 --- /dev/null +++ b/include/net/netfilter/nf_synproxy.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _NF_SYNPROXY_SHARED_H +#define _NF_SYNPROXY_SHARED_H + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <net/ip6_checksum.h> +#include <net/ip6_route.h> +#include <net/tcp.h> + +#include <net/netfilter/nf_conntrack_seqadj.h> +#include <net/netfilter/nf_conntrack_synproxy.h> + +void synproxy_send_client_synack(struct net *net, const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts); + +bool synproxy_recv_client_ack(struct net *net, + const struct sk_buff *skb, + const struct tcphdr *th, + struct synproxy_options *opts, u32 recv_seq); + +unsigned int ipv4_synproxy_hook(void *priv, struct sk_buff *skb, + const struct nf_hook_state *nhs); +int nf_synproxy_ipv4_init(struct synproxy_net *snet, struct net *net); +void nf_synproxy_ipv4_fini(struct synproxy_net *snet, struct net *net); + +#if IS_ENABLED(CONFIG_IPV6) +void synproxy_send_client_synack_ipv6(struct net *net, + const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts); + +bool synproxy_recv_client_ack_ipv6(struct net *net, const struct sk_buff *skb, + const struct tcphdr *th, + struct synproxy_options *opts, u32 recv_seq); + +unsigned int ipv6_synproxy_hook(void *priv, struct sk_buff *skb, + const struct nf_hook_state *nhs); +int nf_synproxy_ipv6_init(struct synproxy_net *snet, struct net *net); +void nf_synproxy_ipv6_fini(struct synproxy_net *snet, struct net *net); +#endif /* CONFIG_IPV6 */ + +#endif /* _NF_SYNPROXY_SHARED_H */ diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c index 690b17ef6a44..7f7979734fb4 100644 --- a/net/ipv4/netfilter/ipt_SYNPROXY.c +++ b/net/ipv4/netfilter/ipt_SYNPROXY.c @@ -6,258 +6,11 @@ * published by the Free Software Foundation. */ -#include <linux/module.h> -#include <linux/skbuff.h> -#include <net/tcp.h> - #include <linux/netfilter_ipv4/ip_tables.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_SYNPROXY.h> -#include <net/netfilter/nf_conntrack.h> -#include <net/netfilter/nf_conntrack_seqadj.h> -#include <net/netfilter/nf_conntrack_synproxy.h> -#include <net/netfilter/nf_conntrack_ecache.h> - -static struct iphdr * -synproxy_build_ip(struct net *net, struct sk_buff *skb, __be32 saddr, - __be32 daddr) -{ - struct iphdr *iph; - - skb_reset_network_header(skb); - iph = skb_put(skb, sizeof(*iph)); - iph->version = 4; - iph->ihl = sizeof(*iph) / 4; - iph->tos = 0; - iph->id = 0; - iph->frag_off = htons(IP_DF); - iph->ttl = net->ipv4.sysctl_ip_default_ttl; - iph->protocol = IPPROTO_TCP; - iph->check = 0; - iph->saddr = saddr; - iph->daddr = daddr; - - return iph; -} - -static void -synproxy_send_tcp(struct net *net, - const struct sk_buff *skb, struct sk_buff *nskb, - struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo, - struct iphdr *niph, struct tcphdr *nth, - unsigned int tcp_hdr_size) -{ - nth->check = ~tcp_v4_check(tcp_hdr_size, niph->saddr, niph->daddr, 0); - nskb->ip_summed = CHECKSUM_PARTIAL; - nskb->csum_start = (unsigned char *)nth - nskb->head; - nskb->csum_offset = offsetof(struct tcphdr, check); - - skb_dst_set_noref(nskb, skb_dst(skb)); - nskb->protocol = htons(ETH_P_IP); - if (ip_route_me_harder(net, nskb, RTN_UNSPEC)) - goto free_nskb; - - if (nfct) { - nf_ct_set(nskb, (struct nf_conn *)nfct, ctinfo); - nf_conntrack_get(nfct); - } - - ip_local_out(net, nskb->sk, nskb); - return; - -free_nskb: - kfree_skb(nskb); -} - -static void -synproxy_send_client_synack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct iphdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - u16 mss = opts->mss; - - iph = ip_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->dest; - nth->dest = th->source; - nth->seq = htonl(__cookie_v4_init_sequence(iph, th, &mss)); - nth->ack_seq = htonl(ntohl(th->seq) + 1); - tcp_flag_word(nth) = TCP_FLAG_SYN | TCP_FLAG_ACK; - if (opts->options & XT_SYNPROXY_OPT_ECN) - tcp_flag_word(nth) |= TCP_FLAG_ECE; - nth->doff = tcp_hdr_size / 4; - nth->window = 0; - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), - IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); -} - -static void -synproxy_send_server_syn(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts, u32 recv_seq) -{ - struct synproxy_net *snet = synproxy_pernet(net); - struct sk_buff *nskb; - struct iphdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ip_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->source; - nth->dest = th->dest; - nth->seq = htonl(recv_seq - 1); - /* ack_seq is used to relay our ISN to the synproxy hook to initialize - * sequence number translation once a connection tracking entry exists. - */ - nth->ack_seq = htonl(ntohl(th->ack_seq) - 1); - tcp_flag_word(nth) = TCP_FLAG_SYN; - if (opts->options & XT_SYNPROXY_OPT_ECN) - tcp_flag_word(nth) |= TCP_FLAG_ECE | TCP_FLAG_CWR; - nth->doff = tcp_hdr_size / 4; - nth->window = th->window; - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW, - niph, nth, tcp_hdr_size); -} - -static void -synproxy_send_server_ack(struct net *net, - const struct ip_ct_tcp *state, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct iphdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ip_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr); - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->dest; - nth->dest = th->source; - nth->seq = htonl(ntohl(th->ack_seq)); - nth->ack_seq = htonl(ntohl(th->seq) + 1); - tcp_flag_word(nth) = TCP_FLAG_ACK; - nth->doff = tcp_hdr_size / 4; - nth->window = htons(state->seen[IP_CT_DIR_ORIGINAL].td_maxwin); - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); -} - -static void -synproxy_send_client_ack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct iphdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ip_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->source; - nth->dest = th->dest; - nth->seq = htonl(ntohl(th->seq) + 1); - nth->ack_seq = th->ack_seq; - tcp_flag_word(nth) = TCP_FLAG_ACK; - nth->doff = tcp_hdr_size / 4; - nth->window = htons(ntohs(th->window) >> opts->wscale); - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), - IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); -} - -static bool -synproxy_recv_client_ack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - struct synproxy_options *opts, u32 recv_seq) -{ - struct synproxy_net *snet = synproxy_pernet(net); - int mss; - - mss = __cookie_v4_check(ip_hdr(skb), th, ntohl(th->ack_seq) - 1); - if (mss == 0) { - this_cpu_inc(snet->stats->cookie_invalid); - return false; - } - - this_cpu_inc(snet->stats->cookie_valid); - opts->mss = mss; - opts->options |= XT_SYNPROXY_OPT_MSS; - - if (opts->options & XT_SYNPROXY_OPT_TIMESTAMP) - synproxy_check_timestamp_cookie(opts); - - synproxy_send_server_syn(net, skb, th, opts, recv_seq); - return true; -} +#include <net/netfilter/nf_synproxy.h> static unsigned int synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par) @@ -309,135 +62,6 @@ synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par) return XT_CONTINUE; } -static unsigned int ipv4_synproxy_hook(void *priv, - struct sk_buff *skb, - const struct nf_hook_state *nhs) -{ - struct net *net = nhs->net; - struct synproxy_net *snet = synproxy_pernet(net); - enum ip_conntrack_info ctinfo; - struct nf_conn *ct; - struct nf_conn_synproxy *synproxy; - struct synproxy_options opts = {}; - const struct ip_ct_tcp *state; - struct tcphdr *th, _th; - unsigned int thoff; - - ct = nf_ct_get(skb, &ctinfo); - if (ct == NULL) - return NF_ACCEPT; - - synproxy = nfct_synproxy(ct); - if (synproxy == NULL) - return NF_ACCEPT; - - if (nf_is_loopback_packet(skb) || - ip_hdr(skb)->protocol != IPPROTO_TCP) - return NF_ACCEPT; - - thoff = ip_hdrlen(skb); - th = skb_header_pointer(skb, thoff, sizeof(_th), &_th); - if (th == NULL) - return NF_DROP; - - state = &ct->proto.tcp; - switch (state->state) { - case TCP_CONNTRACK_CLOSE: - if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { - nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - - ntohl(th->seq) + 1); - break; - } - - if (!th->syn || th->ack || - CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) - break; - - /* Reopened connection - reset the sequence number and timestamp - * adjustments, they will get initialized once the connection is - * reestablished. - */ - nf_ct_seqadj_init(ct, ctinfo, 0); - synproxy->tsoff = 0; - this_cpu_inc(snet->stats->conn_reopened); - - /* fall through */ - case TCP_CONNTRACK_SYN_SENT: - if (!synproxy_parse_options(skb, thoff, th, &opts)) - return NF_DROP; - - if (!th->syn && th->ack && - CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) { - /* Keep-Alives are sent with SEG.SEQ = SND.NXT-1, - * therefore we need to add 1 to make the SYN sequence - * number match the one of first SYN. - */ - if (synproxy_recv_client_ack(net, skb, th, &opts, - ntohl(th->seq) + 1)) { - this_cpu_inc(snet->stats->cookie_retrans); - consume_skb(skb); - return NF_STOLEN; - } else { - return NF_DROP; - } - } - - synproxy->isn = ntohl(th->ack_seq); - if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP) - synproxy->its = opts.tsecr; - - nf_conntrack_event_cache(IPCT_SYNPROXY, ct); - break; - case TCP_CONNTRACK_SYN_RECV: - if (!th->syn || !th->ack) - break; - - if (!synproxy_parse_options(skb, thoff, th, &opts)) - return NF_DROP; - - if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP) { - synproxy->tsoff = opts.tsval - synproxy->its; - nf_conntrack_event_cache(IPCT_SYNPROXY, ct); - } - - opts.options &= ~(XT_SYNPROXY_OPT_MSS | - XT_SYNPROXY_OPT_WSCALE | - XT_SYNPROXY_OPT_SACK_PERM); - - swap(opts.tsval, opts.tsecr); - synproxy_send_server_ack(net, state, skb, th, &opts); - - nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq)); - nf_conntrack_event_cache(IPCT_SEQADJ, ct); - - swap(opts.tsval, opts.tsecr); - synproxy_send_client_ack(net, skb, th, &opts); - - consume_skb(skb); - return NF_STOLEN; - default: - break; - } - - synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy); - return NF_ACCEPT; -} - -static const struct nf_hook_ops ipv4_synproxy_ops[] = { - { - .hook = ipv4_synproxy_hook, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, - }, - { - .hook = ipv4_synproxy_hook, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_POST_ROUTING, - .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, - }, -}; - static int synproxy_tg4_check(const struct xt_tgchk_param *par) { struct synproxy_net *snet = synproxy_pernet(par->net); @@ -452,13 +76,10 @@ static int synproxy_tg4_check(const struct xt_tgchk_param *par) if (err) return err; - if (snet->hook_ref4 == 0) { - err = nf_register_net_hooks(par->net, ipv4_synproxy_ops, - ARRAY_SIZE(ipv4_synproxy_ops)); - if (err) { - nf_ct_netns_put(par->net, par->family); - return err; - } + err = nf_synproxy_ipv4_init(snet, par->net); + if (err) { + nf_ct_netns_put(par->net, par->family); + return err; } snet->hook_ref4++; @@ -469,10 +90,7 @@ static void synproxy_tg4_destroy(const struct xt_tgdtor_param *par) { struct synproxy_net *snet = synproxy_pernet(par->net); - snet->hook_ref4--; - if (snet->hook_ref4 == 0) - nf_unregister_net_hooks(par->net, ipv4_synproxy_ops, - ARRAY_SIZE(ipv4_synproxy_ops)); + nf_synproxy_ipv4_fini(snet, par->net); nf_ct_netns_put(par->net, par->family); } diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c index cb6d42b03cb5..55a9b92d0a1f 100644 --- a/net/ipv6/netfilter/ip6t_SYNPROXY.c +++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c @@ -6,272 +6,11 @@ * published by the Free Software Foundation. */ -#include <linux/module.h> -#include <linux/skbuff.h> -#include <net/ip6_checksum.h> -#include <net/ip6_route.h> -#include <net/tcp.h> - #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_SYNPROXY.h> -#include <net/netfilter/nf_conntrack.h> -#include <net/netfilter/nf_conntrack_seqadj.h> -#include <net/netfilter/nf_conntrack_synproxy.h> -#include <net/netfilter/nf_conntrack_ecache.h> - -static struct ipv6hdr * -synproxy_build_ip(struct net *net, struct sk_buff *skb, - const struct in6_addr *saddr, - const struct in6_addr *daddr) -{ - struct ipv6hdr *iph; - - skb_reset_network_header(skb); - iph = skb_put(skb, sizeof(*iph)); - ip6_flow_hdr(iph, 0, 0); - iph->hop_limit = net->ipv6.devconf_all->hop_limit; - iph->nexthdr = IPPROTO_TCP; - iph->saddr = *saddr; - iph->daddr = *daddr; - - return iph; -} - -static void -synproxy_send_tcp(struct net *net, - const struct sk_buff *skb, struct sk_buff *nskb, - struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo, - struct ipv6hdr *niph, struct tcphdr *nth, - unsigned int tcp_hdr_size) -{ - struct dst_entry *dst; - struct flowi6 fl6; - - nth->check = ~tcp_v6_check(tcp_hdr_size, &niph->saddr, &niph->daddr, 0); - nskb->ip_summed = CHECKSUM_PARTIAL; - nskb->csum_start = (unsigned char *)nth - nskb->head; - nskb->csum_offset = offsetof(struct tcphdr, check); - - memset(&fl6, 0, sizeof(fl6)); - fl6.flowi6_proto = IPPROTO_TCP; - fl6.saddr = niph->saddr; - fl6.daddr = niph->daddr; - fl6.fl6_sport = nth->source; - fl6.fl6_dport = nth->dest; - security_skb_classify_flow((struct sk_buff *)skb, flowi6_to_flowi(&fl6)); - dst = ip6_route_output(net, NULL, &fl6); - if (dst->error) { - dst_release(dst); - goto free_nskb; - } - dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0); - if (IS_ERR(dst)) - goto free_nskb; - - skb_dst_set(nskb, dst); - - if (nfct) { - nf_ct_set(nskb, (struct nf_conn *)nfct, ctinfo); - nf_conntrack_get(nfct); - } - - ip6_local_out(net, nskb->sk, nskb); - return; - -free_nskb: - kfree_skb(nskb); -} - -static void -synproxy_send_client_synack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct ipv6hdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - u16 mss = opts->mss; - - iph = ipv6_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, &iph->daddr, &iph->saddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->dest; - nth->dest = th->source; - nth->seq = htonl(__cookie_v6_init_sequence(iph, th, &mss)); - nth->ack_seq = htonl(ntohl(th->seq) + 1); - tcp_flag_word(nth) = TCP_FLAG_SYN | TCP_FLAG_ACK; - if (opts->options & XT_SYNPROXY_OPT_ECN) - tcp_flag_word(nth) |= TCP_FLAG_ECE; - nth->doff = tcp_hdr_size / 4; - nth->window = 0; - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), - IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); -} -static void -synproxy_send_server_syn(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts, u32 recv_seq) -{ - struct synproxy_net *snet = synproxy_pernet(net); - struct sk_buff *nskb; - struct ipv6hdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ipv6_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, &iph->saddr, &iph->daddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->source; - nth->dest = th->dest; - nth->seq = htonl(recv_seq - 1); - /* ack_seq is used to relay our ISN to the synproxy hook to initialize - * sequence number translation once a connection tracking entry exists. - */ - nth->ack_seq = htonl(ntohl(th->ack_seq) - 1); - tcp_flag_word(nth) = TCP_FLAG_SYN; - if (opts->options & XT_SYNPROXY_OPT_ECN) - tcp_flag_word(nth) |= TCP_FLAG_ECE | TCP_FLAG_CWR; - nth->doff = tcp_hdr_size / 4; - nth->window = th->window; - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW, - niph, nth, tcp_hdr_size); -} - -static void -synproxy_send_server_ack(struct net *net, - const struct ip_ct_tcp *state, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct ipv6hdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ipv6_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, &iph->daddr, &iph->saddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->dest; - nth->dest = th->source; - nth->seq = htonl(ntohl(th->ack_seq)); - nth->ack_seq = htonl(ntohl(th->seq) + 1); - tcp_flag_word(nth) = TCP_FLAG_ACK; - nth->doff = tcp_hdr_size / 4; - nth->window = htons(state->seen[IP_CT_DIR_ORIGINAL].td_maxwin); - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); -} - -static void -synproxy_send_client_ack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - const struct synproxy_options *opts) -{ - struct sk_buff *nskb; - struct ipv6hdr *iph, *niph; - struct tcphdr *nth; - unsigned int tcp_hdr_size; - - iph = ipv6_hdr(skb); - - tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); - nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, - GFP_ATOMIC); - if (nskb == NULL) - return; - skb_reserve(nskb, MAX_TCP_HEADER); - - niph = synproxy_build_ip(net, nskb, &iph->saddr, &iph->daddr); - - skb_reset_transport_header(nskb); - nth = skb_put(nskb, tcp_hdr_size); - nth->source = th->source; - nth->dest = th->dest; - nth->seq = htonl(ntohl(th->seq) + 1); - nth->ack_seq = th->ack_seq; - tcp_flag_word(nth) = TCP_FLAG_ACK; - nth->doff = tcp_hdr_size / 4; - nth->window = htons(ntohs(th->window) >> opts->wscale); - nth->check = 0; - nth->urg_ptr = 0; - - synproxy_build_options(nth, opts); - - synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), - IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); -} - -static bool -synproxy_recv_client_ack(struct net *net, - const struct sk_buff *skb, const struct tcphdr *th, - struct synproxy_options *opts, u32 recv_seq) -{ - struct synproxy_net *snet = synproxy_pernet(net); - int mss; - - mss = __cookie_v6_check(ipv6_hdr(skb), th, ntohl(th->ack_seq) - 1); - if (mss == 0) { - this_cpu_inc(snet->stats->cookie_invalid); - return false; - } - - this_cpu_inc(snet->stats->cookie_valid); - opts->mss = mss; - opts->options |= XT_SYNPROXY_OPT_MSS; - - if (opts->options & XT_SYNPROXY_OPT_TIMESTAMP) - synproxy_check_timestamp_cookie(opts); - - synproxy_send_server_syn(net, skb, th, opts, recv_seq); - return true; -} +#include <net/netfilter/nf_synproxy.h> static unsigned int synproxy_tg6(struct sk_buff *skb, const struct xt_action_param *par) @@ -307,13 +46,14 @@ synproxy_tg6(struct sk_buff *skb, const struct xt_action_param *par) XT_SYNPROXY_OPT_SACK_PERM | XT_SYNPROXY_OPT_ECN); - synproxy_send_client_synack(net, skb, th, &opts); + synproxy_send_client_synack_ipv6(net, skb, th, &opts); consume_skb(skb); return NF_STOLEN; } else if (th->ack && !(th->fin || th->rst || th->syn)) { /* ACK from client */ - if (synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq))) { + if (synproxy_recv_client_ack_ipv6(net, skb, th, &opts, + ntohl(th->seq))) { consume_skb(skb); return NF_STOLEN; } else { @@ -324,141 +64,6 @@ synproxy_tg6(struct sk_buff *skb, const struct xt_action_param *par) return XT_CONTINUE; } -static unsigned int ipv6_synproxy_hook(void *priv, - struct sk_buff *skb, - const struct nf_hook_state *nhs) -{ - struct net *net = nhs->net; - struct synproxy_net *snet = synproxy_pernet(net); - enum ip_conntrack_info ctinfo; - struct nf_conn *ct; - struct nf_conn_synproxy *synproxy; - struct synproxy_options opts = {}; - const struct ip_ct_tcp *state; - struct tcphdr *th, _th; - __be16 frag_off; - u8 nexthdr; - int thoff; - - ct = nf_ct_get(skb, &ctinfo); - if (ct == NULL) - return NF_ACCEPT; - - synproxy = nfct_synproxy(ct); - if (synproxy == NULL) - return NF_ACCEPT; - - if (nf_is_loopback_packet(skb)) - return NF_ACCEPT; - - nexthdr = ipv6_hdr(skb)->nexthdr; - thoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, - &frag_off); - if (thoff < 0 || nexthdr != IPPROTO_TCP) - return NF_ACCEPT; - - th = skb_header_pointer(skb, thoff, sizeof(_th), &_th); - if (th == NULL) - return NF_DROP; - - state = &ct->proto.tcp; - switch (state->state) { - case TCP_CONNTRACK_CLOSE: - if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { - nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - - ntohl(th->seq) + 1); - break; - } - - if (!th->syn || th->ack || - CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) - break; - - /* Reopened connection - reset the sequence number and timestamp - * adjustments, they will get initialized once the connection is - * reestablished. - */ - nf_ct_seqadj_init(ct, ctinfo, 0); - synproxy->tsoff = 0; - this_cpu_inc(snet->stats->conn_reopened); - - /* fall through */ - case TCP_CONNTRACK_SYN_SENT: - if (!synproxy_parse_options(skb, thoff, th, &opts)) - return NF_DROP; - - if (!th->syn && th->ack && - CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) { - /* Keep-Alives are sent with SEG.SEQ = SND.NXT-1, - * therefore we need to add 1 to make the SYN sequence - * number match the one of first SYN. - */ - if (synproxy_recv_client_ack(net, skb, th, &opts, - ntohl(th->seq) + 1)) { - this_cpu_inc(snet->stats->cookie_retrans); - consume_skb(skb); - return NF_STOLEN; - } else { - return NF_DROP; - } - } - - synproxy->isn = ntohl(th->ack_seq); - if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP) - synproxy->its = opts.tsecr; - - nf_conntrack_event_cache(IPCT_SYNPROXY, ct); - break; - case TCP_CONNTRACK_SYN_RECV: - if (!th->syn || !th->ack) - break; - - if (!synproxy_parse_options(skb, thoff, th, &opts)) - return NF_DROP; - - if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP) { - synproxy->tsoff = opts.tsval - synproxy->its; - nf_conntrack_event_cache(IPCT_SYNPROXY, ct); - } - - opts.options &= ~(XT_SYNPROXY_OPT_MSS | - XT_SYNPROXY_OPT_WSCALE | - XT_SYNPROXY_OPT_SACK_PERM); - - swap(opts.tsval, opts.tsecr); - synproxy_send_server_ack(net, state, skb, th, &opts); - - nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq)); - nf_conntrack_event_cache(IPCT_SEQADJ, ct); - - swap(opts.tsval, opts.tsecr); - synproxy_send_client_ack(net, skb, th, &opts); - - consume_skb(skb); - return NF_STOLEN; - default: - break; - } - - synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy); - return NF_ACCEPT; -} - -static const struct nf_hook_ops ipv6_synproxy_ops[] = { - { - .hook = ipv6_synproxy_hook, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, - }, - { - .hook = ipv6_synproxy_hook, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_POST_ROUTING, - .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, - }, -}; - static int synproxy_tg6_check(const struct xt_tgchk_param *par) { struct synproxy_net *snet = synproxy_pernet(par->net); @@ -474,16 +79,12 @@ static int synproxy_tg6_check(const struct xt_tgchk_param *par) if (err) return err; - if (snet->hook_ref6 == 0) { - err = nf_register_net_hooks(par->net, ipv6_synproxy_ops, - ARRAY_SIZE(ipv6_synproxy_ops)); - if (err) { - nf_ct_netns_put(par->net, par->family); - return err; - } + err = nf_synproxy_ipv6_init(snet, par->net); + if (err) { + nf_ct_netns_put(par->net, par->family); + return err; } - snet->hook_ref6++; return err; } @@ -491,10 +92,7 @@ static void synproxy_tg6_destroy(const struct xt_tgdtor_param *par) { struct synproxy_net *snet = synproxy_pernet(par->net); - snet->hook_ref6--; - if (snet->hook_ref6 == 0) - nf_unregister_net_hooks(par->net, ipv6_synproxy_ops, - ARRAY_SIZE(ipv6_synproxy_ops)); + nf_synproxy_ipv6_fini(snet, par->net); nf_ct_netns_put(par->net, par->family); } diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c index 3d58a9e93e5a..50677285f82e 100644 --- a/net/netfilter/nf_synproxy_core.c +++ b/net/netfilter/nf_synproxy_core.c @@ -13,16 +13,16 @@ #include <net/netns/generic.h> #include <linux/proc_fs.h> -#include <linux/netfilter_ipv4/ip_tables.h> -#include <linux/netfilter/x_tables.h> -#include <linux/netfilter/xt_tcpudp.h> -#include <linux/netfilter/xt_SYNPROXY.h> +#include <linux/netfilter_ipv6.h> +#include <linux/netfilter/nf_SYNPROXY.h> #include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_ecache.h> #include <net/netfilter/nf_conntrack_extend.h> #include <net/netfilter/nf_conntrack_seqadj.h> #include <net/netfilter/nf_conntrack_synproxy.h> #include <net/netfilter/nf_conntrack_zones.h> +#include <net/netfilter/nf_synproxy.h> unsigned int synproxy_net_id; EXPORT_SYMBOL_GPL(synproxy_net_id); @@ -60,7 +60,7 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, case TCPOPT_MSS: if (opsize == TCPOLEN_MSS) { opts->mss = get_unaligned_be16(ptr); - opts->options |= XT_SYNPROXY_OPT_MSS; + opts->options |= NF_SYNPROXY_OPT_MSS; } break; case TCPOPT_WINDOW: @@ -68,19 +68,19 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, opts->wscale = *ptr; if (opts->wscale > TCP_MAX_WSCALE) opts->wscale = TCP_MAX_WSCALE; - opts->options |= XT_SYNPROXY_OPT_WSCALE; + opts->options |= NF_SYNPROXY_OPT_WSCALE; } break; case TCPOPT_TIMESTAMP: if (opsize == TCPOLEN_TIMESTAMP) { opts->tsval = get_unaligned_be32(ptr); opts->tsecr = get_unaligned_be32(ptr + 4); - opts->options |= XT_SYNPROXY_OPT_TIMESTAMP; + opts->options |= NF_SYNPROXY_OPT_TIMESTAMP; } break; case TCPOPT_SACK_PERM: if (opsize == TCPOLEN_SACK_PERM) - opts->options |= XT_SYNPROXY_OPT_SACK_PERM; + opts->options |= NF_SYNPROXY_OPT_SACK_PERM; break; } @@ -92,36 +92,36 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, } EXPORT_SYMBOL_GPL(synproxy_parse_options); -unsigned int synproxy_options_size(const struct synproxy_options *opts) +static unsigned int +synproxy_options_size(const struct synproxy_options *opts) { unsigned int size = 0; - if (opts->options & XT_SYNPROXY_OPT_MSS) + if (opts->options & NF_SYNPROXY_OPT_MSS) size += TCPOLEN_MSS_ALIGNED; - if (opts->options & XT_SYNPROXY_OPT_TIMESTAMP) + if (opts->options & NF_SYNPROXY_OPT_TIMESTAMP) size += TCPOLEN_TSTAMP_ALIGNED; - else if (opts->options & XT_SYNPROXY_OPT_SACK_PERM) + else if (opts->options & NF_SYNPROXY_OPT_SACK_PERM) size += TCPOLEN_SACKPERM_ALIGNED; - if (opts->options & XT_SYNPROXY_OPT_WSCALE) + if (opts->options & NF_SYNPROXY_OPT_WSCALE) size += TCPOLEN_WSCALE_ALIGNED; return size; } -EXPORT_SYMBOL_GPL(synproxy_options_size); -void +static void synproxy_build_options(struct tcphdr *th, const struct synproxy_options *opts) { __be32 *ptr = (__be32 *)(th + 1); u8 options = opts->options; - if (options & XT_SYNPROXY_OPT_MSS) + if (options & NF_SYNPROXY_OPT_MSS) *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | opts->mss); - if (options & XT_SYNPROXY_OPT_TIMESTAMP) { - if (options & XT_SYNPROXY_OPT_SACK_PERM) + if (options & NF_SYNPROXY_OPT_TIMESTAMP) { + if (options & NF_SYNPROXY_OPT_SACK_PERM) *ptr++ = htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | (TCPOPT_TIMESTAMP << 8) | @@ -134,58 +134,56 @@ synproxy_build_options(struct tcphdr *th, const struct synproxy_options *opts) *ptr++ = htonl(opts->tsval); *ptr++ = htonl(opts->tsecr); - } else if (options & XT_SYNPROXY_OPT_SACK_PERM) + } else if (options & NF_SYNPROXY_OPT_SACK_PERM) *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); - if (options & XT_SYNPROXY_OPT_WSCALE) + if (options & NF_SYNPROXY_OPT_WSCALE) *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | opts->wscale); } -EXPORT_SYMBOL_GPL(synproxy_build_options); -void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info, +void synproxy_init_timestamp_cookie(const struct nf_synproxy_info *info, struct synproxy_options *opts) { opts->tsecr = opts->tsval; opts->tsval = tcp_time_stamp_raw() & ~0x3f; - if (opts->options & XT_SYNPROXY_OPT_WSCALE) { + if (opts->options & NF_SYNPROXY_OPT_WSCALE) { opts->tsval |= opts->wscale; opts->wscale = info->wscale; } else opts->tsval |= 0xf; - if (opts->options & XT_SYNPROXY_OPT_SACK_PERM) + if (opts->options & NF_SYNPROXY_OPT_SACK_PERM) opts->tsval |= 1 << 4; - if (opts->options & XT_SYNPROXY_OPT_ECN) + if (opts->options & NF_SYNPROXY_OPT_ECN) opts->tsval |= 1 << 5; } EXPORT_SYMBOL_GPL(synproxy_init_timestamp_cookie); -void synproxy_check_timestamp_cookie(struct synproxy_options *opts) +static void +synproxy_check_timestamp_cookie(struct synproxy_options *opts) { opts->wscale = opts->tsecr & 0xf; if (opts->wscale != 0xf) - opts->options |= XT_SYNPROXY_OPT_WSCALE; + opts->options |= NF_SYNPROXY_OPT_WSCALE; - opts->options |= opts->tsecr & (1 << 4) ? XT_SYNPROXY_OPT_SACK_PERM : 0; + opts->options |= opts->tsecr & (1 << 4) ? NF_SYNPROXY_OPT_SACK_PERM : 0; - opts->options |= opts->tsecr & (1 << 5) ? XT_SYNPROXY_OPT_ECN : 0; + opts->options |= opts->tsecr & (1 << 5) ? NF_SYNPROXY_OPT_ECN : 0; } -EXPORT_SYMBOL_GPL(synproxy_check_timestamp_cookie); -unsigned int synproxy_tstamp_adjust(struct sk_buff *skb, - unsigned int protoff, - struct tcphdr *th, - struct nf_conn *ct, - enum ip_conntrack_info ctinfo, - const struct nf_conn_synproxy *synproxy) +static unsigned int +synproxy_tstamp_adjust(struct sk_buff *skb, unsigned int protoff, + struct tcphdr *th, struct nf_conn *ct, + enum ip_conntrack_info ctinfo, + const struct nf_conn_synproxy *synproxy) { unsigned int optoff, optend; __be32 *ptr, old; @@ -235,7 +233,6 @@ unsigned int synproxy_tstamp_adjust(struct sk_buff *skb, } return 1; } -EXPORT_SYMBOL_GPL(synproxy_tstamp_adjust); static struct nf_ct_ext_type nf_ct_synproxy_extend __read_mostly = { .len = sizeof(struct nf_conn_synproxy), @@ -416,5 +413,830 @@ static void __exit synproxy_core_exit(void) module_init(synproxy_core_init); module_exit(synproxy_core_exit); +static struct iphdr * +synproxy_build_ip(struct net *net, struct sk_buff *skb, __be32 saddr, + __be32 daddr) +{ + struct iphdr *iph; + + skb_reset_network_header(skb); + iph = skb_put(skb, sizeof(*iph)); + iph->version = 4; + iph->ihl = sizeof(*iph) / 4; + iph->tos = 0; + iph->id = 0; + iph->frag_off = htons(IP_DF); + iph->ttl = net->ipv4.sysctl_ip_default_ttl; + iph->protocol = IPPROTO_TCP; + iph->check = 0; + iph->saddr = saddr; + iph->daddr = daddr; + + return iph; +} + +static void +synproxy_send_tcp(struct net *net, + const struct sk_buff *skb, struct sk_buff *nskb, + struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo, + struct iphdr *niph, struct tcphdr *nth, + unsigned int tcp_hdr_size) +{ + nth->check = ~tcp_v4_check(tcp_hdr_size, niph->saddr, niph->daddr, 0); + nskb->ip_summed = CHECKSUM_PARTIAL; + nskb->csum_start = (unsigned char *)nth - nskb->head; + nskb->csum_offset = offsetof(struct tcphdr, check); + + skb_dst_set_noref(nskb, skb_dst(skb)); + nskb->protocol = htons(ETH_P_IP); + if (ip_route_me_harder(net, nskb, RTN_UNSPEC)) + goto free_nskb; + + if (nfct) { + nf_ct_set(nskb, (struct nf_conn *)nfct, ctinfo); + nf_conntrack_get(nfct); + } + + ip_local_out(net, nskb->sk, nskb); + return; + +free_nskb: + kfree_skb(nskb); +} + +void +synproxy_send_client_synack(struct net *net, + const struct sk_buff *skb, const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct iphdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + u16 mss = opts->mss; + + iph = ip_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->dest; + nth->dest = th->source; + nth->seq = htonl(__cookie_v4_init_sequence(iph, th, &mss)); + nth->ack_seq = htonl(ntohl(th->seq) + 1); + tcp_flag_word(nth) = TCP_FLAG_SYN | TCP_FLAG_ACK; + if (opts->options & NF_SYNPROXY_OPT_ECN) + tcp_flag_word(nth) |= TCP_FLAG_ECE; + nth->doff = tcp_hdr_size / 4; + nth->window = 0; + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), + IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); +} +EXPORT_SYMBOL_GPL(synproxy_send_client_synack); + +static void +synproxy_send_server_syn(struct net *net, + const struct sk_buff *skb, const struct tcphdr *th, + const struct synproxy_options *opts, u32 recv_seq) +{ + struct synproxy_net *snet = synproxy_pernet(net); + struct sk_buff *nskb; + struct iphdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ip_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->source; + nth->dest = th->dest; + nth->seq = htonl(recv_seq - 1); + /* ack_seq is used to relay our ISN to the synproxy hook to initialize + * sequence number translation once a connection tracking entry exists. + */ + nth->ack_seq = htonl(ntohl(th->ack_seq) - 1); + tcp_flag_word(nth) = TCP_FLAG_SYN; + if (opts->options & NF_SYNPROXY_OPT_ECN) + tcp_flag_word(nth) |= TCP_FLAG_ECE | TCP_FLAG_CWR; + nth->doff = tcp_hdr_size / 4; + nth->window = th->window; + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp(net, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW, + niph, nth, tcp_hdr_size); +} + +static void +synproxy_send_server_ack(struct net *net, + const struct ip_ct_tcp *state, + const struct sk_buff *skb, const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct iphdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ip_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->dest; + nth->dest = th->source; + nth->seq = htonl(ntohl(th->ack_seq)); + nth->ack_seq = htonl(ntohl(th->seq) + 1); + tcp_flag_word(nth) = TCP_FLAG_ACK; + nth->doff = tcp_hdr_size / 4; + nth->window = htons(state->seen[IP_CT_DIR_ORIGINAL].td_maxwin); + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp(net, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); +} + +static void +synproxy_send_client_ack(struct net *net, + const struct sk_buff *skb, const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct iphdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ip_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->source; + nth->dest = th->dest; + nth->seq = htonl(ntohl(th->seq) + 1); + nth->ack_seq = th->ack_seq; + tcp_flag_word(nth) = TCP_FLAG_ACK; + nth->doff = tcp_hdr_size / 4; + nth->window = htons(ntohs(th->window) >> opts->wscale); + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp(net, skb, nskb, skb_nfct(skb), + IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); +} + +bool +synproxy_recv_client_ack(struct net *net, + const struct sk_buff *skb, const struct tcphdr *th, + struct synproxy_options *opts, u32 recv_seq) +{ + struct synproxy_net *snet = synproxy_pernet(net); + int mss; + + mss = __cookie_v4_check(ip_hdr(skb), th, ntohl(th->ack_seq) - 1); + if (mss == 0) { + this_cpu_inc(snet->stats->cookie_invalid); + return false; + } + + this_cpu_inc(snet->stats->cookie_valid); + opts->mss = mss; + opts->options |= NF_SYNPROXY_OPT_MSS; + + if (opts->options & NF_SYNPROXY_OPT_TIMESTAMP) + synproxy_check_timestamp_cookie(opts); + + synproxy_send_server_syn(net, skb, th, opts, recv_seq); + return true; +} +EXPORT_SYMBOL_GPL(synproxy_recv_client_ack); + +unsigned int +ipv4_synproxy_hook(void *priv, struct sk_buff *skb, + const struct nf_hook_state *nhs) +{ + struct net *net = nhs->net; + struct synproxy_net *snet = synproxy_pernet(net); + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + struct nf_conn_synproxy *synproxy; + struct synproxy_options opts = {}; + const struct ip_ct_tcp *state; + struct tcphdr *th, _th; + unsigned int thoff; + + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + return NF_ACCEPT; + + synproxy = nfct_synproxy(ct); + if (!synproxy) + return NF_ACCEPT; + + if (nf_is_loopback_packet(skb) || + ip_hdr(skb)->protocol != IPPROTO_TCP) + return NF_ACCEPT; + + thoff = ip_hdrlen(skb); + th = skb_header_pointer(skb, thoff, sizeof(_th), &_th); + if (!th) + return NF_DROP; + + state = &ct->proto.tcp; + switch (state->state) { + case TCP_CONNTRACK_CLOSE: + if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { + nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - + ntohl(th->seq) + 1); + break; + } + + if (!th->syn || th->ack || + CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) + break; + + /* Reopened connection - reset the sequence number and timestamp + * adjustments, they will get initialized once the connection is + * reestablished. + */ + nf_ct_seqadj_init(ct, ctinfo, 0); + synproxy->tsoff = 0; + this_cpu_inc(snet->stats->conn_reopened); + + /* fall through */ + case TCP_CONNTRACK_SYN_SENT: + if (!synproxy_parse_options(skb, thoff, th, &opts)) + return NF_DROP; + + if (!th->syn && th->ack && + CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) { + /* Keep-Alives are sent with SEG.SEQ = SND.NXT-1, + * therefore we need to add 1 to make the SYN sequence + * number match the one of first SYN. + */ + if (synproxy_recv_client_ack(net, skb, th, &opts, + ntohl(th->seq) + 1)) { + this_cpu_inc(snet->stats->cookie_retrans); + consume_skb(skb); + return NF_STOLEN; + } else { + return NF_DROP; + } + } + + synproxy->isn = ntohl(th->ack_seq); + if (opts.options & NF_SYNPROXY_OPT_TIMESTAMP) + synproxy->its = opts.tsecr; + + nf_conntrack_event_cache(IPCT_SYNPROXY, ct); + break; + case TCP_CONNTRACK_SYN_RECV: + if (!th->syn || !th->ack) + break; + + if (!synproxy_parse_options(skb, thoff, th, &opts)) + return NF_DROP; + + if (opts.options & NF_SYNPROXY_OPT_TIMESTAMP) { + synproxy->tsoff = opts.tsval - synproxy->its; + nf_conntrack_event_cache(IPCT_SYNPROXY, ct); + } + + opts.options &= ~(NF_SYNPROXY_OPT_MSS | + NF_SYNPROXY_OPT_WSCALE | + NF_SYNPROXY_OPT_SACK_PERM); + + swap(opts.tsval, opts.tsecr); + synproxy_send_server_ack(net, state, skb, th, &opts); + + nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq)); + nf_conntrack_event_cache(IPCT_SEQADJ, ct); + + swap(opts.tsval, opts.tsecr); + synproxy_send_client_ack(net, skb, th, &opts); + + consume_skb(skb); + return NF_STOLEN; + default: + break; + } + + synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy); + return NF_ACCEPT; +} +EXPORT_SYMBOL_GPL(ipv4_synproxy_hook); + +static const struct nf_hook_ops ipv4_synproxy_ops[] = { + { + .hook = ipv4_synproxy_hook, + .pf = NFPROTO_IPV4, + .hooknum = NF_INET_LOCAL_IN, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, + }, + { + .hook = ipv4_synproxy_hook, + .pf = NFPROTO_IPV4, + .hooknum = NF_INET_POST_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, + }, +}; + +int nf_synproxy_ipv4_init(struct synproxy_net *snet, struct net *net) +{ + int err; + + if (snet->hook_ref4 == 0) { + err = nf_register_net_hooks(net, ipv4_synproxy_ops, + ARRAY_SIZE(ipv4_synproxy_ops)); + if (err) + return err; + } + + snet->hook_ref4++; + return err; +} +EXPORT_SYMBOL_GPL(nf_synproxy_ipv4_init); + +void nf_synproxy_ipv4_fini(struct synproxy_net *snet, struct net *net) +{ + snet->hook_ref4--; + if (snet->hook_ref4 == 0) + nf_unregister_net_hooks(net, ipv4_synproxy_ops, + ARRAY_SIZE(ipv4_synproxy_ops)); +} +EXPORT_SYMBOL_GPL(nf_synproxy_ipv4_fini); + +#if IS_ENABLED(CONFIG_IPV6) +static struct ipv6hdr * +synproxy_build_ip_ipv6(struct net *net, struct sk_buff *skb, + const struct in6_addr *saddr, + const struct in6_addr *daddr) +{ + struct ipv6hdr *iph; + + skb_reset_network_header(skb); + iph = skb_put(skb, sizeof(*iph)); + ip6_flow_hdr(iph, 0, 0); + iph->hop_limit = net->ipv6.devconf_all->hop_limit; + iph->nexthdr = IPPROTO_TCP; + iph->saddr = *saddr; + iph->daddr = *daddr; + + return iph; +} + +static void +synproxy_send_tcp_ipv6(struct net *net, + const struct sk_buff *skb, struct sk_buff *nskb, + struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo, + struct ipv6hdr *niph, struct tcphdr *nth, + unsigned int tcp_hdr_size) +{ + struct dst_entry *dst; + struct flowi6 fl6; + int err; + + nth->check = ~tcp_v6_check(tcp_hdr_size, &niph->saddr, &niph->daddr, 0); + nskb->ip_summed = CHECKSUM_PARTIAL; + nskb->csum_start = (unsigned char *)nth - nskb->head; + nskb->csum_offset = offsetof(struct tcphdr, check); + + memset(&fl6, 0, sizeof(fl6)); + fl6.flowi6_proto = IPPROTO_TCP; + fl6.saddr = niph->saddr; + fl6.daddr = niph->daddr; + fl6.fl6_sport = nth->source; + fl6.fl6_dport = nth->dest; + security_skb_classify_flow((struct sk_buff *)skb, + flowi6_to_flowi(&fl6)); + err = nf_ip6_route(net, &dst, flowi6_to_flowi(&fl6), false); + if (err) { + goto free_nskb; + } + + dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0); + if (IS_ERR(dst)) + goto free_nskb; + + skb_dst_set(nskb, dst); + + if (nfct) { + nf_ct_set(nskb, (struct nf_conn *)nfct, ctinfo); + nf_conntrack_get(nfct); + } + + ip6_local_out(net, nskb->sk, nskb); + return; + +free_nskb: + kfree_skb(nskb); +} + +void +synproxy_send_client_synack_ipv6(struct net *net, + const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct ipv6hdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + u16 mss = opts->mss; + + iph = ipv6_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip_ipv6(net, nskb, &iph->daddr, &iph->saddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->dest; + nth->dest = th->source; + nth->seq = htonl(nf_ipv6_cookie_init_sequence(iph, th, &mss)); + nth->ack_seq = htonl(ntohl(th->seq) + 1); + tcp_flag_word(nth) = TCP_FLAG_SYN | TCP_FLAG_ACK; + if (opts->options & NF_SYNPROXY_OPT_ECN) + tcp_flag_word(nth) |= TCP_FLAG_ECE; + nth->doff = tcp_hdr_size / 4; + nth->window = 0; + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp_ipv6(net, skb, nskb, skb_nfct(skb), + IP_CT_ESTABLISHED_REPLY, niph, nth, + tcp_hdr_size); +} +EXPORT_SYMBOL_GPL(synproxy_send_client_synack_ipv6); + +static void +synproxy_send_server_syn_ipv6(struct net *net, const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts, u32 recv_seq) +{ + struct synproxy_net *snet = synproxy_pernet(net); + struct sk_buff *nskb; + struct ipv6hdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ipv6_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip_ipv6(net, nskb, &iph->saddr, &iph->daddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->source; + nth->dest = th->dest; + nth->seq = htonl(recv_seq - 1); + /* ack_seq is used to relay our ISN to the synproxy hook to initialize + * sequence number translation once a connection tracking entry exists. + */ + nth->ack_seq = htonl(ntohl(th->ack_seq) - 1); + tcp_flag_word(nth) = TCP_FLAG_SYN; + if (opts->options & NF_SYNPROXY_OPT_ECN) + tcp_flag_word(nth) |= TCP_FLAG_ECE | TCP_FLAG_CWR; + nth->doff = tcp_hdr_size / 4; + nth->window = th->window; + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp_ipv6(net, skb, nskb, &snet->tmpl->ct_general, + IP_CT_NEW, niph, nth, tcp_hdr_size); +} + +static void +synproxy_send_server_ack_ipv6(struct net *net, const struct ip_ct_tcp *state, + const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct ipv6hdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ipv6_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip_ipv6(net, nskb, &iph->daddr, &iph->saddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->dest; + nth->dest = th->source; + nth->seq = htonl(ntohl(th->ack_seq)); + nth->ack_seq = htonl(ntohl(th->seq) + 1); + tcp_flag_word(nth) = TCP_FLAG_ACK; + nth->doff = tcp_hdr_size / 4; + nth->window = htons(state->seen[IP_CT_DIR_ORIGINAL].td_maxwin); + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp_ipv6(net, skb, nskb, NULL, 0, niph, nth, + tcp_hdr_size); +} + +static void +synproxy_send_client_ack_ipv6(struct net *net, const struct sk_buff *skb, + const struct tcphdr *th, + const struct synproxy_options *opts) +{ + struct sk_buff *nskb; + struct ipv6hdr *iph, *niph; + struct tcphdr *nth; + unsigned int tcp_hdr_size; + + iph = ipv6_hdr(skb); + + tcp_hdr_size = sizeof(*nth) + synproxy_options_size(opts); + nskb = alloc_skb(sizeof(*niph) + tcp_hdr_size + MAX_TCP_HEADER, + GFP_ATOMIC); + if (!nskb) + return; + skb_reserve(nskb, MAX_TCP_HEADER); + + niph = synproxy_build_ip_ipv6(net, nskb, &iph->saddr, &iph->daddr); + + skb_reset_transport_header(nskb); + nth = skb_put(nskb, tcp_hdr_size); + nth->source = th->source; + nth->dest = th->dest; + nth->seq = htonl(ntohl(th->seq) + 1); + nth->ack_seq = th->ack_seq; + tcp_flag_word(nth) = TCP_FLAG_ACK; + nth->doff = tcp_hdr_size / 4; + nth->window = htons(ntohs(th->window) >> opts->wscale); + nth->check = 0; + nth->urg_ptr = 0; + + synproxy_build_options(nth, opts); + + synproxy_send_tcp_ipv6(net, skb, nskb, skb_nfct(skb), + IP_CT_ESTABLISHED_REPLY, niph, nth, + tcp_hdr_size); +} + +bool +synproxy_recv_client_ack_ipv6(struct net *net, + const struct sk_buff *skb, + const struct tcphdr *th, + struct synproxy_options *opts, u32 recv_seq) +{ + struct synproxy_net *snet = synproxy_pernet(net); + int mss; + + mss = __cookie_v6_check(ipv6_hdr(skb), th, ntohl(th->ack_seq) - 1); + if (mss == 0) { + this_cpu_inc(snet->stats->cookie_invalid); + return false; + } + + this_cpu_inc(snet->stats->cookie_valid); + opts->mss = mss; + opts->options |= NF_SYNPROXY_OPT_MSS; + + if (opts->options & NF_SYNPROXY_OPT_TIMESTAMP) + synproxy_check_timestamp_cookie(opts); + + synproxy_send_server_syn_ipv6(net, skb, th, opts, recv_seq); + return true; +} +EXPORT_SYMBOL_GPL(synproxy_recv_client_ack_ipv6); + +unsigned int +ipv6_synproxy_hook(void *priv, struct sk_buff *skb, + const struct nf_hook_state *nhs) +{ + struct net *net = nhs->net; + struct synproxy_net *snet = synproxy_pernet(net); + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + struct nf_conn_synproxy *synproxy; + struct synproxy_options opts = {}; + const struct ip_ct_tcp *state; + struct tcphdr *th, _th; + __be16 frag_off; + u8 nexthdr; + int thoff; + + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + return NF_ACCEPT; + + synproxy = nfct_synproxy(ct); + if (!synproxy) + return NF_ACCEPT; + + if (nf_is_loopback_packet(skb)) + return NF_ACCEPT; + + nexthdr = ipv6_hdr(skb)->nexthdr; + thoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, + &frag_off); + if (thoff < 0 || nexthdr != IPPROTO_TCP) + return NF_ACCEPT; + + th = skb_header_pointer(skb, thoff, sizeof(_th), &_th); + if (!th) + return NF_DROP; + + state = &ct->proto.tcp; + switch (state->state) { + case TCP_CONNTRACK_CLOSE: + if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { + nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - + ntohl(th->seq) + 1); + break; + } + + if (!th->syn || th->ack || + CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) + break; + + /* Reopened connection - reset the sequence number and timestamp + * adjustments, they will get initialized once the connection is + * reestablished. + */ + nf_ct_seqadj_init(ct, ctinfo, 0); + synproxy->tsoff = 0; + this_cpu_inc(snet->stats->conn_reopened); + + /* fall through */ + case TCP_CONNTRACK_SYN_SENT: + if (!synproxy_parse_options(skb, thoff, th, &opts)) + return NF_DROP; + + if (!th->syn && th->ack && + CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) { + /* Keep-Alives are sent with SEG.SEQ = SND.NXT-1, + * therefore we need to add 1 to make the SYN sequence + * number match the one of first SYN. + */ + if (synproxy_recv_client_ack_ipv6(net, skb, th, &opts, + ntohl(th->seq) + 1)) { + this_cpu_inc(snet->stats->cookie_retrans); + consume_skb(skb); + return NF_STOLEN; + } else { + return NF_DROP; + } + } + + synproxy->isn = ntohl(th->ack_seq); + if (opts.options & NF_SYNPROXY_OPT_TIMESTAMP) + synproxy->its = opts.tsecr; + + nf_conntrack_event_cache(IPCT_SYNPROXY, ct); + break; + case TCP_CONNTRACK_SYN_RECV: + if (!th->syn || !th->ack) + break; + + if (!synproxy_parse_options(skb, thoff, th, &opts)) + return NF_DROP; + + if (opts.options & NF_SYNPROXY_OPT_TIMESTAMP) { + synproxy->tsoff = opts.tsval - synproxy->its; + nf_conntrack_event_cache(IPCT_SYNPROXY, ct); + } + + opts.options &= ~(NF_SYNPROXY_OPT_MSS | + NF_SYNPROXY_OPT_WSCALE | + NF_SYNPROXY_OPT_SACK_PERM); + + swap(opts.tsval, opts.tsecr); + synproxy_send_server_ack_ipv6(net, state, skb, th, &opts); + + nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq)); + nf_conntrack_event_cache(IPCT_SEQADJ, ct); + + swap(opts.tsval, opts.tsecr); + synproxy_send_client_ack_ipv6(net, skb, th, &opts); + + consume_skb(skb); + return NF_STOLEN; + default: + break; + } + + synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy); + return NF_ACCEPT; +} +EXPORT_SYMBOL_GPL(ipv6_synproxy_hook); + +static const struct nf_hook_ops ipv6_synproxy_ops[] = { + { + .hook = ipv6_synproxy_hook, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_LOCAL_IN, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, + }, + { + .hook = ipv6_synproxy_hook, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_POST_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM - 1, + }, +}; + +int +nf_synproxy_ipv6_init(struct synproxy_net *snet, struct net *net) +{ + int err; + + if (snet->hook_ref6 == 0) { + err = nf_register_net_hooks(net, ipv6_synproxy_ops, + ARRAY_SIZE(ipv6_synproxy_ops)); + if (err) + return err; + } + + snet->hook_ref6++; + return err; +} +EXPORT_SYMBOL_GPL(nf_synproxy_ipv6_init); + +void +nf_synproxy_ipv6_fini(struct synproxy_net *snet, struct net *net) +{ + snet->hook_ref6--; + if (snet->hook_ref6 == 0) + nf_unregister_net_hooks(net, ipv6_synproxy_ops, + ARRAY_SIZE(ipv6_synproxy_ops)); +} +EXPORT_SYMBOL_GPL(nf_synproxy_ipv6_fini); +#endif /* CONFIG_IPV6 */ + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |