text: /* Copyright (C) 2011-2013 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   *
   * 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.
   */
  
  /* Kernel module implementing an IP set type: the hash:net,iface 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 <linux/rbtree.h>
  #include <net/ip.h>
  #include <net/ipv6.h>
  #include <net/netlink.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    nomatch flag support added */
  /*				2    /0 support added */
  /*				3    Counters support added */
  /*				4    Comments support added */
  /*				5    Forceadd support added */
  #define IPSET_TYPE_REV_MAX	6 /* skbinfo support added */
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
  IP_SET_MODULE_DESC("hash:net,iface", IPSET_TYPE_REV_MIN, IPSET_TYPE_REV_MAX);
  MODULE_ALIAS("ip_set_hash:net,iface");
  
  /* Interface name rbtree */
  
  struct iface_node {
  	struct rb_node node;
  	char iface[IFNAMSIZ];
  };
  
  #define iface_data(n)	(rb_entry(n, struct iface_node, node)->iface)
  
  static void
  rbtree_destroy(struct rb_root *root)
  {
  	struct iface_node *node, *next;
  
  	rbtree_postorder_for_each_entry_safe(node, next, root, node)
  		kfree(node);
  
  	*root = RB_ROOT;
  }
  
  static int
  iface_test(struct rb_root *root, const char **iface)
  {
  	struct rb_node *n = root->rb_node;
  
  	while (n) {
  		const char *d = iface_data(n);
  		int res = strcmp(*iface, d);
  
  		if (res < 0)
  			n = n->rb_left;
  		else if (res > 0)
  			n = n->rb_right;
  		else {
  			*iface = d;
  			return 1;
  		}
  	}
  	return 0;
  }
  
  static int
  iface_add(struct rb_root *root, const char **iface)
  {
  	struct rb_node **n = &(root->rb_node), *p = NULL;
  	struct iface_node *d;
  
  	while (*n) {
  		char *ifname = iface_data(*n);
  		int res = strcmp(*iface, ifname);
  
  		p = *n;
  		if (res < 0)
  			n = &((*n)->rb_left);
  		else if (res > 0)
  			n = &((*n)->rb_right);
  		else {
  			*iface = ifname;
  			return 0;
  		}
  	}
  
  	d = kzalloc(sizeof(*d), GFP_ATOMIC);
  	if (!d)
  		return -ENOMEM;
  	strcpy(d->iface, *iface);
  
  	rb_link_node(&d->node, p, n);
  	rb_insert_color(&d->node, root);
  
  	*iface = d->iface;
  	return 0;
  }
  
  /* Type specific function prefix */
  #define HTYPE		hash_netiface
  #define IP_SET_HASH_WITH_NETS
  #define IP_SET_HASH_WITH_RBTREE
  #define IP_SET_HASH_WITH_MULTI
  #define IP_SET_HASH_WITH_NET0
  
  #define STREQ(a, b)	(strcmp(a, b) == 0)
  
  /* IPv4 variant */
  
  struct hash_netiface4_elem_hashed {
  	__be32 ip;
  	u8 physdev;
  	u8 cidr;
  	u8 nomatch;
  	u8 elem;
  };
  
  /* Member elements */
  struct hash_netiface4_elem {
  	__be32 ip;
  	u8 physdev;
  	u8 cidr;
  	u8 nomatch;
  	u8 elem;
  	const char *iface;
  };
  
  /* Common functions */
  
  static inline bool
  hash_netiface4_data_equal(const struct hash_netiface4_elem *ip1,
  			  const struct hash_netiface4_elem *ip2,
  			  u32 *multi)
  {
  	return ip1->ip == ip2->ip &&
  	       ip1->cidr == ip2->cidr &&
  	       (++*multi) &&
  	       ip1->physdev == ip2->physdev &&
  	       ip1->iface == ip2->iface;
  }
  
  static inline int
  hash_netiface4_do_data_match(const struct hash_netiface4_elem *elem)
  {
  	return elem->nomatch ? -ENOTEMPTY : 1;
  }
  
  static inline void
  hash_netiface4_data_set_flags(struct hash_netiface4_elem *elem, u32 flags)
  {
  	elem->nomatch = (flags >> 16) & IPSET_FLAG_NOMATCH;
  }
  
  static inline void
  hash_netiface4_data_reset_flags(struct hash_netiface4_elem *elem, u8 *flags)
  {
  	swap(*flags, elem->nomatch);
  }
  
  static inline void
  hash_netiface4_data_netmask(struct hash_netiface4_elem *elem, u8 cidr)
  {
  	elem->ip &= ip_set_netmask(cidr);
  	elem->cidr = cidr;
  }
  
  static bool
  hash_netiface4_data_list(struct sk_buff *skb,
  			 const struct hash_netiface4_elem *data)
  {
  	u32 flags = data->physdev ? IPSET_FLAG_PHYSDEV : 0;
  
  	if (data->nomatch)
  		flags |= IPSET_FLAG_NOMATCH;
  	if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, data->ip) ||
  	    nla_put_u8(skb, IPSET_ATTR_CIDR, data->cidr) ||
  	    nla_put_string(skb, IPSET_ATTR_IFACE, data->iface) ||
  	    (flags &&
  	     nla_put_net32(skb, IPSET_ATTR_CADT_FLAGS, htonl(flags))))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return 1;
  }
  
  static inline void
  hash_netiface4_data_next(struct hash_netiface4_elem *next,
  			 const struct hash_netiface4_elem *d)
  {
  	next->ip = d->ip;
  }
  
  #define MTYPE		hash_netiface4
  #define PF		4
  #define HOST_MASK	32
  #define HKEY_DATALEN	sizeof(struct hash_netiface4_elem_hashed)
  #include "ip_set_hash_gen.h"
  
  static int
  hash_netiface4_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)
  {
  	struct hash_netiface *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_netiface4_elem e = {
  		.cidr = IP_SET_INIT_CIDR(h->nets[0].cidr[0], HOST_MASK),
  		.elem = 1,
  	};
  	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
  	int ret;
  
  	if (e.cidr == 0)
  		return -EINVAL;
  	if (adt == IPSET_TEST)
  		e.cidr = HOST_MASK;
  
  	ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip);
  	e.ip &= ip_set_netmask(e.cidr);
  
  #define IFACE(dir)	(par->dir ? par->dir->name : NULL)
  #define PHYSDEV(dir)	(nf_bridge->dir ? nf_bridge->dir->name : NULL)
  #define SRCDIR		(opt->flags & IPSET_DIM_TWO_SRC)
  
  	if (opt->cmdflags & IPSET_FLAG_PHYSDEV) {
  #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  		const struct nf_bridge_info *nf_bridge = skb->nf_bridge;
  
  		if (!nf_bridge)
  			return -EINVAL;
  		e.iface = SRCDIR ? PHYSDEV(physindev) : PHYSDEV(physoutdev);
  		e.physdev = 1;
  #else
  		e.iface = NULL;
  #endif
  	} else
  		e.iface = SRCDIR ? IFACE(in) : IFACE(out);
  
  	if (!e.iface)
  		return -EINVAL;
  	ret = iface_test(&h->rbtree, &e.iface);
  	if (adt == IPSET_ADD) {
  		if (!ret) {
  			ret = iface_add(&h->rbtree, &e.iface);
  			if (ret)
  				return ret;
  		}
  	} else if (!ret)
  		return ret;
  
  	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
  }
  
  static int
  hash_netiface4_uadt(struct ip_set *set, struct nlattr *tb[],
  		    enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
  {
  	struct hash_netiface *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_netiface4_elem e = { .cidr = HOST_MASK, .elem = 1 };
  	struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
  	u32 ip = 0, ip_to = 0, last;
  	char iface[IFNAMSIZ];
  	int ret;
  
  	if (unlikely(!tb[IPSET_ATTR_IP] ||
  		     !tb[IPSET_ATTR_IFACE] ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_PACKETS) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_BYTES) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBMARK) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBPRIO) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBQUEUE)))
  		return -IPSET_ERR_PROTOCOL;
  
  	if (tb[IPSET_ATTR_LINENO])
  		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
  
  	ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP], &ip) ||
  	      ip_set_get_extensions(set, tb, &ext);
  	if (ret)
  		return ret;
  
  	if (tb[IPSET_ATTR_CIDR]) {
  		e.cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
  		if (e.cidr > HOST_MASK)
  			return -IPSET_ERR_INVALID_CIDR;
  	}
  
  	strcpy(iface, nla_data(tb[IPSET_ATTR_IFACE]));
  	e.iface = iface;
  	ret = iface_test(&h->rbtree, &e.iface);
  	if (adt == IPSET_ADD) {
  		if (!ret) {
  			ret = iface_add(&h->rbtree, &e.iface);
  			if (ret)
  				return ret;
  		}
  	} else if (!ret)
  		return ret;
  
  	if (tb[IPSET_ATTR_CADT_FLAGS]) {
  		u32 cadt_flags = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);
  		if (cadt_flags & IPSET_FLAG_PHYSDEV)
  			e.physdev = 1;
  		if (cadt_flags & IPSET_FLAG_NOMATCH)
  			flags |= (IPSET_FLAG_NOMATCH << 16);
  	}
  	if (adt == IPSET_TEST || !tb[IPSET_ATTR_IP_TO]) {
  		e.ip = htonl(ip & ip_set_hostmask(e.cidr));
  		ret = adtfn(set, &e, &ext, &ext, flags);
  		return ip_set_enomatch(ret, flags, adt, set) ? -ret :
  		       ip_set_eexist(ret, flags) ? 0 : ret;
  	}
  
  	if (tb[IPSET_ATTR_IP_TO]) {
  		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
  		if (ret)
  			return ret;
  		if (ip_to < ip)
  			swap(ip, ip_to);
  		if (ip + UINT_MAX == ip_to)
  			return -IPSET_ERR_HASH_RANGE;
  	} else
  		ip_set_mask_from_to(ip, ip_to, e.cidr);
  
  	if (retried)
  		ip = ntohl(h->next.ip);
  	while (!after(ip, ip_to)) {
  		e.ip = htonl(ip);
  		last = ip_set_range_to_cidr(ip, ip_to, &e.cidr);
  		ret = adtfn(set, &e, &ext, &ext, flags);
  
  		if (ret && !ip_set_eexist(ret, flags))
  			return ret;
  		else
  			ret = 0;
  		ip = last + 1;
  	}
  	return ret;
  }
  
  /* IPv6 variant */
  
  struct hash_netiface6_elem_hashed {
  	union nf_inet_addr ip;
  	u8 physdev;
  	u8 cidr;
  	u8 nomatch;
  	u8 elem;
  };
  
  struct hash_netiface6_elem {
  	union nf_inet_addr ip;
  	u8 physdev;
  	u8 cidr;
  	u8 nomatch;
  	u8 elem;
  	const char *iface;
  };
  
  /* Common functions */
  
  static inline bool
  hash_netiface6_data_equal(const struct hash_netiface6_elem *ip1,
  			  const struct hash_netiface6_elem *ip2,
  			  u32 *multi)
  {
  	return ipv6_addr_equal(&ip1->ip.in6, &ip2->ip.in6) &&
  	       ip1->cidr == ip2->cidr &&
  	       (++*multi) &&
  	       ip1->physdev == ip2->physdev &&
  	       ip1->iface == ip2->iface;
  }
  
  static inline int
  hash_netiface6_do_data_match(const struct hash_netiface6_elem *elem)
  {
  	return elem->nomatch ? -ENOTEMPTY : 1;
  }
  
  static inline void
  hash_netiface6_data_set_flags(struct hash_netiface6_elem *elem, u32 flags)
  {
  	elem->nomatch = (flags >> 16) & IPSET_FLAG_NOMATCH;
  }
  
  static inline void
  hash_netiface6_data_reset_flags(struct hash_netiface6_elem *elem, u8 *flags)
  {
  	swap(*flags, elem->nomatch);
  }
  
  static inline void
  hash_netiface6_data_netmask(struct hash_netiface6_elem *elem, u8 cidr)
  {
  	ip6_netmask(&elem->ip, cidr);
  	elem->cidr = cidr;
  }
  
  static bool
  hash_netiface6_data_list(struct sk_buff *skb,
  			 const struct hash_netiface6_elem *data)
  {
  	u32 flags = data->physdev ? IPSET_FLAG_PHYSDEV : 0;
  
  	if (data->nomatch)
  		flags |= IPSET_FLAG_NOMATCH;
  	if (nla_put_ipaddr6(skb, IPSET_ATTR_IP, &data->ip.in6) ||
  	    nla_put_u8(skb, IPSET_ATTR_CIDR, data->cidr) ||
  	    nla_put_string(skb, IPSET_ATTR_IFACE, data->iface) ||
  	    (flags &&
  	     nla_put_net32(skb, IPSET_ATTR_CADT_FLAGS, htonl(flags))))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return 1;
  }
  
  static inline void
  hash_netiface6_data_next(struct hash_netiface4_elem *next,
  			 const struct hash_netiface6_elem *d)
  {
  }
  
  #undef MTYPE
  #undef PF
  #undef HOST_MASK
  #undef HKEY_DATALEN
  
  #define MTYPE		hash_netiface6
  #define PF		6
  #define HOST_MASK	128
  #define HKEY_DATALEN	sizeof(struct hash_netiface6_elem_hashed)
  #define IP_SET_EMIT_CREATE
  #include "ip_set_hash_gen.h"
  
  static int
  hash_netiface6_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)
  {
  	struct hash_netiface *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_netiface6_elem e = {
  		.cidr = IP_SET_INIT_CIDR(h->nets[0].cidr[0], HOST_MASK),
  		.elem = 1,
  	};
  	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
  	int ret;
  
  	if (e.cidr == 0)
  		return -EINVAL;
  	if (adt == IPSET_TEST)
  		e.cidr = HOST_MASK;
  
  	ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip.in6);
  	ip6_netmask(&e.ip, e.cidr);
  
  	if (opt->cmdflags & IPSET_FLAG_PHYSDEV) {
  #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  		const struct nf_bridge_info *nf_bridge = skb->nf_bridge;
  
  		if (!nf_bridge)
  			return -EINVAL;
  		e.iface = SRCDIR ? PHYSDEV(physindev) : PHYSDEV(physoutdev);
  		e.physdev = 1;
  #else
  		e.iface = NULL;
  #endif
  	} else
  		e.iface = SRCDIR ? IFACE(in) : IFACE(out);
  
  	if (!e.iface)
  		return -EINVAL;
  	ret = iface_test(&h->rbtree, &e.iface);
  	if (adt == IPSET_ADD) {
  		if (!ret) {
  			ret = iface_add(&h->rbtree, &e.iface);
  			if (ret)
  				return ret;
  		}
  	} else if (!ret)
  		return ret;
  
  	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
  }
  
  static int
  hash_netiface6_uadt(struct ip_set *set, struct nlattr *tb[],
  		   enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
  {
  	struct hash_netiface *h = set->data;
  	ipset_adtfn adtfn = set->variant->adt[adt];
  	struct hash_netiface6_elem e = { .cidr = HOST_MASK, .elem = 1 };
  	struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
  	char iface[IFNAMSIZ];
  	int ret;
  
  	if (unlikely(!tb[IPSET_ATTR_IP] ||
  		     !tb[IPSET_ATTR_IFACE] ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_PACKETS) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_BYTES) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBMARK) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBPRIO) ||
  		     !ip_set_optattr_netorder(tb, IPSET_ATTR_SKBQUEUE)))
  		return -IPSET_ERR_PROTOCOL;
  	if (unlikely(tb[IPSET_ATTR_IP_TO]))
  		return -IPSET_ERR_HASH_RANGE_UNSUPPORTED;
  
  	if (tb[IPSET_ATTR_LINENO])
  		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
  
  	ret = ip_set_get_ipaddr6(tb[IPSET_ATTR_IP], &e.ip) ||
  	      ip_set_get_extensions(set, tb, &ext);
  	if (ret)
  		return ret;
  
  	if (tb[IPSET_ATTR_CIDR])
  		e.cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
  	if (e.cidr > HOST_MASK)
  		return -IPSET_ERR_INVALID_CIDR;
  	ip6_netmask(&e.ip, e.cidr);
  
  	strcpy(iface, nla_data(tb[IPSET_ATTR_IFACE]));
  	e.iface = iface;
  	ret = iface_test(&h->rbtree, &e.iface);
  	if (adt == IPSET_ADD) {
  		if (!ret) {
  			ret = iface_add(&h->rbtree, &e.iface);
  			if (ret)
  				return ret;
  		}
  	} else if (!ret)
  		return ret;
  
  	if (tb[IPSET_ATTR_CADT_FLAGS]) {
  		u32 cadt_flags = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);
  		if (cadt_flags & IPSET_FLAG_PHYSDEV)
  			e.physdev = 1;
  		if (cadt_flags & IPSET_FLAG_NOMATCH)
  			flags |= (IPSET_FLAG_NOMATCH << 16);
  	}
  
  	ret = adtfn(set, &e, &ext, &ext, flags);
  
  	return ip_set_enomatch(ret, flags, adt, set) ? -ret :
  	       ip_set_eexist(ret, flags) ? 0 : ret;
  }
  
  static struct ip_set_type hash_netiface_type __read_mostly = {
  	.name		= "hash:net,iface",
  	.protocol	= IPSET_PROTOCOL,
  	.features	= IPSET_TYPE_IP | IPSET_TYPE_IFACE |
  			  IPSET_TYPE_NOMATCH,
  	.dimension	= IPSET_DIM_TWO,
  	.family		= NFPROTO_UNSPEC,
  	.revision_min	= IPSET_TYPE_REV_MIN,
  	.revision_max	= IPSET_TYPE_REV_MAX,
  	.create		= hash_netiface_create,
  	.create_policy	= {
  		[IPSET_ATTR_HASHSIZE]	= { .type = NLA_U32 },
  		[IPSET_ATTR_MAXELEM]	= { .type = NLA_U32 },
  		[IPSET_ATTR_PROBES]	= { .type = NLA_U8 },
  		[IPSET_ATTR_RESIZE]	= { .type = NLA_U8  },
  		[IPSET_ATTR_PROTO]	= { .type = NLA_U8 },
  		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
  		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
  	},
  	.adt_policy	= {
  		[IPSET_ATTR_IP]		= { .type = NLA_NESTED },
  		[IPSET_ATTR_IP_TO]	= { .type = NLA_NESTED },
  		[IPSET_ATTR_IFACE]	= { .type = NLA_NUL_STRING,
  					    .len  = IFNAMSIZ - 1 },
  		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
  		[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 },
  		[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_netiface_init(void)
  {
  	return ip_set_type_register(&hash_netiface_type);
  }
  
  static void __exit
  hash_netiface_fini(void)
  {
  	ip_set_type_unregister(&hash_netiface_type);
  }
  
  module_init(hash_netiface_init);
  module_exit(hash_netiface_fini);
  