From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- net/netfilter/xt_cluster.c | 175 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 175 insertions(+) create mode 100644 net/netfilter/xt_cluster.c (limited to 'net/netfilter/xt_cluster.c') diff --git a/net/netfilter/xt_cluster.c b/net/netfilter/xt_cluster.c new file mode 100644 index 000000000..a047a5453 --- /dev/null +++ b/net/netfilter/xt_cluster.c @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * (C) 2008-2009 Pablo Neira Ayuso + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include +#include +#include +#include + +#include +#include +#include + +static inline u32 nf_ct_orig_ipv4_src(const struct nf_conn *ct) +{ + return (__force u32)ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip; +} + +static inline const u32 *nf_ct_orig_ipv6_src(const struct nf_conn *ct) +{ + return (__force u32 *)ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip6; +} + +static inline u_int32_t +xt_cluster_hash_ipv4(u_int32_t ip, const struct xt_cluster_match_info *info) +{ + return jhash_1word(ip, info->hash_seed); +} + +static inline u_int32_t +xt_cluster_hash_ipv6(const void *ip, const struct xt_cluster_match_info *info) +{ + return jhash2(ip, NF_CT_TUPLE_L3SIZE / sizeof(__u32), info->hash_seed); +} + +static inline u_int32_t +xt_cluster_hash(const struct nf_conn *ct, + const struct xt_cluster_match_info *info) +{ + u_int32_t hash = 0; + + switch(nf_ct_l3num(ct)) { + case AF_INET: + hash = xt_cluster_hash_ipv4(nf_ct_orig_ipv4_src(ct), info); + break; + case AF_INET6: + hash = xt_cluster_hash_ipv6(nf_ct_orig_ipv6_src(ct), info); + break; + default: + WARN_ON(1); + break; + } + + return reciprocal_scale(hash, info->total_nodes); +} + +static inline bool +xt_cluster_is_multicast_addr(const struct sk_buff *skb, u_int8_t family) +{ + bool is_multicast = false; + + switch(family) { + case NFPROTO_IPV4: + is_multicast = ipv4_is_multicast(ip_hdr(skb)->daddr); + break; + case NFPROTO_IPV6: + is_multicast = ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr); + break; + default: + WARN_ON(1); + break; + } + return is_multicast; +} + +static bool +xt_cluster_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + struct sk_buff *pskb = (struct sk_buff *)skb; + const struct xt_cluster_match_info *info = par->matchinfo; + const struct nf_conn *ct; + enum ip_conntrack_info ctinfo; + unsigned long hash; + + /* This match assumes that all nodes see the same packets. This can be + * achieved if the switch that connects the cluster nodes support some + * sort of 'port mirroring'. However, if your switch does not support + * this, your cluster nodes can reply ARP request using a multicast MAC + * address. Thus, your switch will flood the same packets to the + * cluster nodes with the same multicast MAC address. Using a multicast + * link address is a RFC 1812 (section 3.3.2) violation, but this works + * fine in practise. + * + * Unfortunately, if you use the multicast MAC address, the link layer + * sets skbuff's pkt_type to PACKET_MULTICAST, which is not accepted + * by TCP and others for packets coming to this node. For that reason, + * this match mangles skbuff's pkt_type if it detects a packet + * addressed to a unicast address but using PACKET_MULTICAST. Yes, I + * know, matches should not alter packets, but we are doing this here + * because we would need to add a PKTTYPE target for this sole purpose. + */ + if (!xt_cluster_is_multicast_addr(skb, xt_family(par)) && + skb->pkt_type == PACKET_MULTICAST) { + pskb->pkt_type = PACKET_HOST; + } + + ct = nf_ct_get(skb, &ctinfo); + if (ct == NULL) + return false; + + if (ct->master) + hash = xt_cluster_hash(ct->master, info); + else + hash = xt_cluster_hash(ct, info); + + return !!((1 << hash) & info->node_mask) ^ + !!(info->flags & XT_CLUSTER_F_INV); +} + +static int xt_cluster_mt_checkentry(const struct xt_mtchk_param *par) +{ + struct xt_cluster_match_info *info = par->matchinfo; + int ret; + + if (info->total_nodes > XT_CLUSTER_NODES_MAX) { + pr_info_ratelimited("you have exceeded the maximum number of cluster nodes (%u > %u)\n", + info->total_nodes, XT_CLUSTER_NODES_MAX); + return -EINVAL; + } + if (info->node_mask >= (1ULL << info->total_nodes)) { + pr_info_ratelimited("node mask cannot exceed total number of nodes\n"); + return -EDOM; + } + + ret = nf_ct_netns_get(par->net, par->family); + if (ret < 0) + pr_info_ratelimited("cannot load conntrack support for proto=%u\n", + par->family); + return ret; +} + +static void xt_cluster_mt_destroy(const struct xt_mtdtor_param *par) +{ + nf_ct_netns_put(par->net, par->family); +} + +static struct xt_match xt_cluster_match __read_mostly = { + .name = "cluster", + .family = NFPROTO_UNSPEC, + .match = xt_cluster_mt, + .checkentry = xt_cluster_mt_checkentry, + .matchsize = sizeof(struct xt_cluster_match_info), + .destroy = xt_cluster_mt_destroy, + .me = THIS_MODULE, +}; + +static int __init xt_cluster_mt_init(void) +{ + return xt_register_match(&xt_cluster_match); +} + +static void __exit xt_cluster_mt_fini(void) +{ + xt_unregister_match(&xt_cluster_match); +} + +MODULE_AUTHOR("Pablo Neira Ayuso "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Xtables: hash-based cluster match"); +MODULE_ALIAS("ipt_cluster"); +MODULE_ALIAS("ip6t_cluster"); +module_init(xt_cluster_mt_init); +module_exit(xt_cluster_mt_fini); -- cgit v1.2.3