text: // SPDX-License-Identifier: GPL-2.0-only
  /* Copyright (C) 2003-2013 Jozsef Kadlecsik <kadlec@netfilter.org> */
  
  /* Kernel module implementing an IP set type: the hash:ip type */
  
  #include <linux/jhash.h>
  #include <linux/module.h>
  #include <linux/ip.h>
  #include <linux/skbuff.h>
  #include <linux/errno.h>
  #include <linux/random.h>
  #include <net/ip.h>
  #include <net/ipv6.h>
  #include <net/netlink.h>
  #include <net/tcp.h>
  
  #include <linux/netfilter.h>
  #include <linux/netfilter/ipset/pfxlen.h>
  #include <linux/netfilter/ipset/ip_set.h>
  #include <linux/netfilter/ipset/ip_set_hash.h>
  
  #define IPSET_TYPE_REV_MIN	0
  /*				1	   Counters support */
  /*				2	   Comments support */
  /*				3	   Forceadd support */
  /*				4	   skbinfo support */
  #define IPSET_TYPE_REV_MAX	5	/* bucketsize, initval support  */
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@netfilter.org>");
  IP_SET_MODULE_DESC("hash:ip", IPSET_TYPE_REV_MIN, IPSET_TYPE_REV_MAX);
  MODULE_ALIAS("ip_set_hash:ip");
  
  /* Type specific function prefix */
  #define HTYPE		hash_ip
  #define IP_SET_HASH_WITH_NETMASK
  
  /* IPv4 variant */
  
  /* Member elements */
  struct hash_ip4_elem {
  	/* Zero valued IP addresses cannot be stored */
  	__be32 ip;
  };
  
  /* Common functions */
  
  static bool
  hash_ip4_data_equal(const struct hash_ip4_elem *e1,
  		    const struct hash_ip4_elem *e2,
  		    u32 *multi)
  {
  	return e1->ip == e2->ip;
  }
  
  static bool
  hash_ip4_data_list(struct sk_buff *skb, const struct hash_ip4_elem *e)
  {
  	if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, e->ip))
  		goto nla_put_failure;
  	return false;
  
  nla_put_failure:
  	return true;
  }
  
  static void
  hash_ip4_data_next(struct hash_ip4_elem *next, const struct hash_ip4_elem *e)
  {
  	next->ip = e->ip;
  }
  
  #define MTYPE		hash_ip4
  #define HOST_MASK	32
  #include "ip_set_hash_gen.h"
  
  static int
  hash_ip4_kadt(struct ip_set *set, const struct sk_buff *skb,
  	      const struct xt_action_param *par,
  	      enum ipset_adt adt, struct ip_set_adt_opt *opt)
  {
  	const struct hash_ip4 *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_ip4_elem e = { 0 };
  	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
  	__be32 ip;
  
  	ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &ip);
  	ip &= ip_set_netmask(h->netmask);
  	if (ip == 0)
  		return -EINVAL;
  
  	e.ip = ip;
  	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
  }
  
  static int
  hash_ip4_uadt(struct ip_set *set, struct nlattr *tb[],
  	      enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
  {
  	const struct hash_ip4 *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_ip4_elem e = { 0 };
  	struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
  	u32 ip = 0, ip_to = 0, hosts;
  	int ret = 0;
  
  	if (tb[IPSET_ATTR_LINENO])
  		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
  
  	if (unlikely(!tb[IPSET_ATTR_IP]))
  		return -IPSET_ERR_PROTOCOL;
  
  	ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP], &ip);
  	if (ret)
  		return ret;
  
  	ret = ip_set_get_extensions(set, tb, &ext);
  	if (ret)
  		return ret;
  
  	ip &= ip_set_hostmask(h->netmask);
  	e.ip = htonl(ip);
  	if (e.ip == 0)
  		return -IPSET_ERR_HASH_ELEM;
  
  	if (adt == IPSET_TEST)
  		return adtfn(set, &e, &ext, &ext, flags);
  
  	ip_to = ip;
  	if (tb[IPSET_ATTR_IP_TO]) {
  		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
  		if (ret)
  			return ret;
  		if (ip > ip_to)
  			swap(ip, ip_to);
  	} else if (tb[IPSET_ATTR_CIDR]) {
  		u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
  
  		if (!cidr || cidr > HOST_MASK)
  			return -IPSET_ERR_INVALID_CIDR;
  		ip_set_mask_from_to(ip, ip_to, cidr);
  	}
  
  	hosts = h->netmask == 32 ? 1 : 2 << (32 - h->netmask - 1);
  
  	if (retried) {
  		ip = ntohl(h->next.ip);
  		e.ip = htonl(ip);
  	}
  	for (; ip <= ip_to;) {
  		ret = adtfn(set, &e, &ext, &ext, flags);
  		if (ret && !ip_set_eexist(ret, flags))
  			return ret;
  
  		ip += hosts;
  		e.ip = htonl(ip);
  		if (e.ip == 0)
  			return 0;
  
  		ret = 0;
  	}
  	return ret;
  }
  
  /* IPv6 variant */
  
  /* Member elements */
  struct hash_ip6_elem {
  	union nf_inet_addr ip;
  };
  
  /* Common functions */
  
  static bool
  hash_ip6_data_equal(const struct hash_ip6_elem *ip1,
  		    const struct hash_ip6_elem *ip2,
  		    u32 *multi)
  {
  	return ipv6_addr_equal(&ip1->ip.in6, &ip2->ip.in6);
  }
  
  static void
  hash_ip6_netmask(union nf_inet_addr *ip, u8 prefix)
  {
  	ip6_netmask(ip, prefix);
  }
  
  static bool
  hash_ip6_data_list(struct sk_buff *skb, const struct hash_ip6_elem *e)
  {
  	if (nla_put_ipaddr6(skb, IPSET_ATTR_IP, &e->ip.in6))
  		goto nla_put_failure;
  	return false;
  
  nla_put_failure:
  	return true;
  }
  
  static void
  hash_ip6_data_next(struct hash_ip6_elem *next, const struct hash_ip6_elem *e)
  {
  }
  
  #undef MTYPE
  #undef HOST_MASK
  
  #define MTYPE		hash_ip6
  #define HOST_MASK	128
  
  #define IP_SET_EMIT_CREATE
  #include "ip_set_hash_gen.h"
  
  static int
  hash_ip6_kadt(struct ip_set *set, const struct sk_buff *skb,
  	      const struct xt_action_param *par,
  	      enum ipset_adt adt, struct ip_set_adt_opt *opt)
  {
  	const struct hash_ip6 *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_ip6_elem e = { { .all = { 0 } } };
  	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
  
  	ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip.in6);
  	hash_ip6_netmask(&e.ip, h->netmask);
  	if (ipv6_addr_any(&e.ip.in6))
  		return -EINVAL;
  
  	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
  }
  
  static int
  hash_ip6_uadt(struct ip_set *set, struct nlattr *tb[],
  	      enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
  {
  	const struct hash_ip6 *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_ip6_elem e = { { .all = { 0 } } };
  	struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
  	int ret;
  
  	if (tb[IPSET_ATTR_LINENO])
  		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
  
  	if (unlikely(!tb[IPSET_ATTR_IP]))
  		return -IPSET_ERR_PROTOCOL;
  	if (unlikely(tb[IPSET_ATTR_IP_TO]))
  		return -IPSET_ERR_HASH_RANGE_UNSUPPORTED;
  	if (unlikely(tb[IPSET_ATTR_CIDR])) {
  		u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
  
  		if (cidr != HOST_MASK)
  			return -IPSET_ERR_INVALID_CIDR;
  	}
  
  	ret = ip_set_get_ipaddr6(tb[IPSET_ATTR_IP], &e.ip);
  	if (ret)
  		return ret;
  
  	ret = ip_set_get_extensions(set, tb, &ext);
  	if (ret)
  		return ret;
  
  	hash_ip6_netmask(&e.ip, h->netmask);
  	if (ipv6_addr_any(&e.ip.in6))
  		return -IPSET_ERR_HASH_ELEM;
  
  	ret = adtfn(set, &e, &ext, &ext, flags);
  
  	return ip_set_eexist(ret, flags) ? 0 : ret;
  }
  
  static struct ip_set_type hash_ip_type __read_mostly = {
  	.name		= "hash:ip",
  	.protocol	= IPSET_PROTOCOL,
  	.features	= IPSET_TYPE_IP,
  	.dimension	= IPSET_DIM_ONE,
  	.family		= NFPROTO_UNSPEC,
  	.revision_min	= IPSET_TYPE_REV_MIN,
  	.revision_max	= IPSET_TYPE_REV_MAX,
  	.create_flags[IPSET_TYPE_REV_MAX] = IPSET_CREATE_FLAG_BUCKETSIZE,
  	.create		= hash_ip_create,
  	.create_policy	= {
  		[IPSET_ATTR_HASHSIZE]	= { .type = NLA_U32 },
  		[IPSET_ATTR_MAXELEM]	= { .type = NLA_U32 },
  		[IPSET_ATTR_INITVAL]	= { .type = NLA_U32 },
  		[IPSET_ATTR_BUCKETSIZE]	= { .type = NLA_U8 },
  		[IPSET_ATTR_RESIZE]	= { .type = NLA_U8  },
  		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
  		[IPSET_ATTR_NETMASK]	= { .type = NLA_U8  },
  		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
  	},
  	.adt_policy	= {
  		[IPSET_ATTR_IP]		= { .type = NLA_NESTED },
  		[IPSET_ATTR_IP_TO]	= { .type = NLA_NESTED },
  		[IPSET_ATTR_CIDR]	= { .type = NLA_U8 },
  		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
  		[IPSET_ATTR_LINENO]	= { .type = NLA_U32 },
  		[IPSET_ATTR_BYTES]	= { .type = NLA_U64 },
  		[IPSET_ATTR_PACKETS]	= { .type = NLA_U64 },
  		[IPSET_ATTR_COMMENT]	= { .type = NLA_NUL_STRING,
  					    .len  = IPSET_MAX_COMMENT_SIZE },
  		[IPSET_ATTR_SKBMARK]	= { .type = NLA_U64 },
  		[IPSET_ATTR_SKBPRIO]	= { .type = NLA_U32 },
  		[IPSET_ATTR_SKBQUEUE]	= { .type = NLA_U16 },
  	},
  	.me		= THIS_MODULE,
  };
  
  static int __init
  hash_ip_init(void)
  {
  	return ip_set_type_register(&hash_ip_type);
  }
  
  static void __exit
  hash_ip_fini(void)
  {
  	rcu_barrier();
  	ip_set_type_unregister(&hash_ip_type);
  }
  
  module_init(hash_ip_init);
  module_exit(hash_ip_fini);
  