netlabel: Add a generic way to create ordered linked lists of network addrs

Create an ordered IP address linked list mechanism similar to the core
kernel's linked list construct.  The idea behind this list functionality
is to create an extensibile linked list ordered by IP address mask to
ease the matching of network addresses.  The linked list is ordered with
larger address masks at the front of the list and shorter address masks
at the end to facilitate overriding network entries with individual host
or subnet entries.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Reviewed-by: James Morris <jmorris@namei.org>
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index cc105a1..ab8131a 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -10,7 +10,7 @@
  */
 
 /*
- * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 - 2007
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 - 2008
  *
  * This program is free software;  you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -54,6 +54,7 @@
 #include <asm/atomic.h>
 
 #include "netlabel_user.h"
+#include "netlabel_addrlist.h"
 #include "netlabel_domainhash.h"
 #include "netlabel_unlabeled.h"
 #include "netlabel_mgmt.h"
@@ -76,22 +77,20 @@
 	struct list_head *tbl;
 	u32 size;
 };
+#define netlbl_unlhsh_addr4_entry(iter) \
+	container_of(iter, struct netlbl_unlhsh_addr4, list)
 struct netlbl_unlhsh_addr4 {
-	__be32 addr;
-	__be32 mask;
 	u32 secid;
 
-	u32 valid;
-	struct list_head list;
+	struct netlbl_af4list list;
 	struct rcu_head rcu;
 };
+#define netlbl_unlhsh_addr6_entry(iter) \
+	container_of(iter, struct netlbl_unlhsh_addr6, list)
 struct netlbl_unlhsh_addr6 {
-	struct in6_addr addr;
-	struct in6_addr mask;
 	u32 secid;
 
-	u32 valid;
-	struct list_head list;
+	struct netlbl_af6list list;
 	struct rcu_head rcu;
 };
 struct netlbl_unlhsh_iface {
@@ -274,26 +273,28 @@
 static void netlbl_unlhsh_free_iface(struct rcu_head *entry)
 {
 	struct netlbl_unlhsh_iface *iface;
-	struct netlbl_unlhsh_addr4 *iter4;
-	struct netlbl_unlhsh_addr4 *tmp4;
-	struct netlbl_unlhsh_addr6 *iter6;
-	struct netlbl_unlhsh_addr6 *tmp6;
+	struct netlbl_af4list *iter4;
+	struct netlbl_af4list *tmp4;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	struct netlbl_af6list *iter6;
+	struct netlbl_af6list *tmp6;
+#endif /* IPv6 */
 
 	iface = container_of(entry, struct netlbl_unlhsh_iface, rcu);
 
 	/* no need for locks here since we are the only one with access to this
 	 * structure */
 
-	list_for_each_entry_safe(iter4, tmp4, &iface->addr4_list, list)
-		if (iter4->valid) {
-			list_del_rcu(&iter4->list);
-			kfree(iter4);
-		}
-	list_for_each_entry_safe(iter6, tmp6, &iface->addr6_list, list)
-		if (iter6->valid) {
-			list_del_rcu(&iter6->list);
-			kfree(iter6);
-		}
+	netlbl_af4list_foreach_safe(iter4, tmp4, &iface->addr4_list) {
+		netlbl_af4list_remove_entry(iter4);
+		kfree(netlbl_unlhsh_addr4_entry(iter4));
+	}
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	netlbl_af6list_foreach_safe(iter6, tmp6, &iface->addr6_list) {
+		netlbl_af6list_remove_entry(iter6);
+		kfree(netlbl_unlhsh_addr6_entry(iter6));
+	}
+#endif /* IPv6 */
 	kfree(iface);
 }
 
@@ -316,59 +317,6 @@
 }
 
 /**
- * netlbl_unlhsh_search_addr4 - Search for a matching IPv4 address entry
- * @addr: IPv4 address
- * @iface: the network interface entry
- *
- * Description:
- * Searches the IPv4 address list of the network interface specified by @iface.
- * If a matching address entry is found it is returned, otherwise NULL is
- * returned.  The caller is responsible for calling the rcu_read_[un]lock()
- * functions.
- *
- */
-static struct netlbl_unlhsh_addr4 *netlbl_unlhsh_search_addr4(
-	                               __be32 addr,
-	                               const struct netlbl_unlhsh_iface *iface)
-{
-	struct netlbl_unlhsh_addr4 *iter;
-
-	list_for_each_entry_rcu(iter, &iface->addr4_list, list)
-		if (iter->valid && (addr & iter->mask) == iter->addr)
-			return iter;
-
-	return NULL;
-}
-
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-/**
- * netlbl_unlhsh_search_addr6 - Search for a matching IPv6 address entry
- * @addr: IPv6 address
- * @iface: the network interface entry
- *
- * Description:
- * Searches the IPv6 address list of the network interface specified by @iface.
- * If a matching address entry is found it is returned, otherwise NULL is
- * returned.  The caller is responsible for calling the rcu_read_[un]lock()
- * functions.
- *
- */
-static struct netlbl_unlhsh_addr6 *netlbl_unlhsh_search_addr6(
-	                               const struct in6_addr *addr,
-	                               const struct netlbl_unlhsh_iface *iface)
-{
-	struct netlbl_unlhsh_addr6 *iter;
-
-	list_for_each_entry_rcu(iter, &iface->addr6_list, list)
-		if (iter->valid &&
-		    ipv6_masked_addr_cmp(&iter->addr, &iter->mask, addr) == 0)
-		return iter;
-
-	return NULL;
-}
-#endif /* IPv6 */
-
-/**
  * netlbl_unlhsh_search_iface - Search for a matching interface entry
  * @ifindex: the network interface
  *
@@ -439,43 +387,26 @@
 				   const struct in_addr *mask,
 				   u32 secid)
 {
+	int ret_val;
 	struct netlbl_unlhsh_addr4 *entry;
-	struct netlbl_unlhsh_addr4 *iter;
 
 	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 	if (entry == NULL)
 		return -ENOMEM;
 
-	entry->addr = addr->s_addr & mask->s_addr;
-	entry->mask = mask->s_addr;
-	entry->secid = secid;
-	entry->valid = 1;
+	entry->list.addr = addr->s_addr & mask->s_addr;
+	entry->list.mask = mask->s_addr;
+	entry->list.valid = 1;
 	INIT_RCU_HEAD(&entry->rcu);
+	entry->secid = secid;
 
 	spin_lock(&netlbl_unlhsh_lock);
-	iter = netlbl_unlhsh_search_addr4(entry->addr, iface);
-	if (iter != NULL &&
-	    iter->addr == addr->s_addr && iter->mask == mask->s_addr) {
-		spin_unlock(&netlbl_unlhsh_lock);
-		kfree(entry);
-		return -EEXIST;
-	}
-	/* in order to speed up address searches through the list (the common
-	 * case) we need to keep the list in order based on the size of the
-	 * address mask such that the entry with the widest mask (smallest
-	 * numerical value) appears first in the list */
-	list_for_each_entry_rcu(iter, &iface->addr4_list, list)
-		if (iter->valid &&
-		    ntohl(entry->mask) > ntohl(iter->mask)) {
-			__list_add_rcu(&entry->list,
-				       iter->list.prev,
-				       &iter->list);
-			spin_unlock(&netlbl_unlhsh_lock);
-			return 0;
-		}
-	list_add_tail_rcu(&entry->list, &iface->addr4_list);
+	ret_val = netlbl_af4list_add(&entry->list, &iface->addr4_list);
 	spin_unlock(&netlbl_unlhsh_lock);
-	return 0;
+
+	if (ret_val != 0)
+		kfree(entry);
+	return ret_val;
 }
 
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
@@ -498,47 +429,29 @@
 				   const struct in6_addr *mask,
 				   u32 secid)
 {
+	int ret_val;
 	struct netlbl_unlhsh_addr6 *entry;
-	struct netlbl_unlhsh_addr6 *iter;
 
 	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 	if (entry == NULL)
 		return -ENOMEM;
 
-	ipv6_addr_copy(&entry->addr, addr);
-	entry->addr.s6_addr32[0] &= mask->s6_addr32[0];
-	entry->addr.s6_addr32[1] &= mask->s6_addr32[1];
-	entry->addr.s6_addr32[2] &= mask->s6_addr32[2];
-	entry->addr.s6_addr32[3] &= mask->s6_addr32[3];
-	ipv6_addr_copy(&entry->mask, mask);
-	entry->secid = secid;
-	entry->valid = 1;
+	ipv6_addr_copy(&entry->list.addr, addr);
+	entry->list.addr.s6_addr32[0] &= mask->s6_addr32[0];
+	entry->list.addr.s6_addr32[1] &= mask->s6_addr32[1];
+	entry->list.addr.s6_addr32[2] &= mask->s6_addr32[2];
+	entry->list.addr.s6_addr32[3] &= mask->s6_addr32[3];
+	ipv6_addr_copy(&entry->list.mask, mask);
+	entry->list.valid = 1;
 	INIT_RCU_HEAD(&entry->rcu);
+	entry->secid = secid;
 
 	spin_lock(&netlbl_unlhsh_lock);
-	iter = netlbl_unlhsh_search_addr6(&entry->addr, iface);
-	if (iter != NULL &&
-	    (ipv6_addr_equal(&iter->addr, addr) &&
-	     ipv6_addr_equal(&iter->mask, mask))) {
-		spin_unlock(&netlbl_unlhsh_lock);
-		kfree(entry);
-		return -EEXIST;
-	}
-	/* in order to speed up address searches through the list (the common
-	 * case) we need to keep the list in order based on the size of the
-	 * address mask such that the entry with the widest mask (smallest
-	 * numerical value) appears first in the list */
-	list_for_each_entry_rcu(iter, &iface->addr6_list, list)
-		if (iter->valid &&
-		    ipv6_addr_cmp(&entry->mask, &iter->mask) > 0) {
-			__list_add_rcu(&entry->list,
-				       iter->list.prev,
-				       &iter->list);
-			spin_unlock(&netlbl_unlhsh_lock);
-			return 0;
-		}
-	list_add_tail_rcu(&entry->list, &iface->addr6_list);
+	ret_val = netlbl_af6list_add(&entry->list, &iface->addr6_list);
 	spin_unlock(&netlbl_unlhsh_lock);
+
+	if (ret_val != 0)
+		kfree(entry);
 	return 0;
 }
 #endif /* IPv6 */
@@ -719,22 +632,21 @@
 				      const struct in_addr *mask,
 				      struct netlbl_audit *audit_info)
 {
-	int ret_val = -ENOENT;
+	int ret_val = 0;
+	struct netlbl_af4list *list_entry;
 	struct netlbl_unlhsh_addr4 *entry;
-	struct audit_buffer *audit_buf = NULL;
+	struct audit_buffer *audit_buf;
 	struct net_device *dev;
-	char *secctx = NULL;
+	char *secctx;
 	u32 secctx_len;
 
 	spin_lock(&netlbl_unlhsh_lock);
-	entry = netlbl_unlhsh_search_addr4(addr->s_addr, iface);
-	if (entry != NULL &&
-	    entry->addr == addr->s_addr && entry->mask == mask->s_addr) {
-		entry->valid = 0;
-		list_del_rcu(&entry->list);
-		ret_val = 0;
-	}
+	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
+					   &iface->addr4_list);
 	spin_unlock(&netlbl_unlhsh_lock);
+	if (list_entry == NULL)
+		ret_val = -ENOENT;
+	entry = netlbl_unlhsh_addr4_entry(list_entry);
 
 	audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_STCDEL,
 					      audit_info);
@@ -742,12 +654,12 @@
 		dev = dev_get_by_index(net, iface->ifindex);
 		netlbl_unlabel_audit_addr4(audit_buf,
 					   (dev != NULL ? dev->name : NULL),
-					   entry->addr, entry->mask);
+					   addr->s_addr, mask->s_addr);
 		if (dev != NULL)
 			dev_put(dev);
-		if (security_secid_to_secctx(entry->secid,
-					     &secctx,
-					     &secctx_len) == 0) {
+		if (entry && security_secid_to_secctx(entry->secid,
+						      &secctx,
+						      &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
 		}
@@ -781,23 +693,20 @@
 				      const struct in6_addr *mask,
 				      struct netlbl_audit *audit_info)
 {
-	int ret_val = -ENOENT;
+	int ret_val = 0;
+	struct netlbl_af6list *list_entry;
 	struct netlbl_unlhsh_addr6 *entry;
-	struct audit_buffer *audit_buf = NULL;
+	struct audit_buffer *audit_buf;
 	struct net_device *dev;
-	char *secctx = NULL;
+	char *secctx;
 	u32 secctx_len;
 
 	spin_lock(&netlbl_unlhsh_lock);
-	entry = netlbl_unlhsh_search_addr6(addr, iface);
-	if (entry != NULL &&
-	    (ipv6_addr_equal(&entry->addr, addr) &&
-	     ipv6_addr_equal(&entry->mask, mask))) {
-		entry->valid = 0;
-		list_del_rcu(&entry->list);
-		ret_val = 0;
-	}
+	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
 	spin_unlock(&netlbl_unlhsh_lock);
+	if (list_entry == NULL)
+		ret_val = -ENOENT;
+	entry = netlbl_unlhsh_addr6_entry(list_entry);
 
 	audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_STCDEL,
 					      audit_info);
@@ -808,9 +717,9 @@
 					   addr, mask);
 		if (dev != NULL)
 			dev_put(dev);
-		if (security_secid_to_secctx(entry->secid,
-					     &secctx,
-					     &secctx_len) == 0) {
+		if (entry && security_secid_to_secctx(entry->secid,
+						      &secctx,
+						      &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
 		}
@@ -836,16 +745,18 @@
  */
 static void netlbl_unlhsh_condremove_iface(struct netlbl_unlhsh_iface *iface)
 {
-	struct netlbl_unlhsh_addr4 *iter4;
-	struct netlbl_unlhsh_addr6 *iter6;
+	struct netlbl_af4list *iter4;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	struct netlbl_af6list *iter6;
+#endif /* IPv6 */
 
 	spin_lock(&netlbl_unlhsh_lock);
-	list_for_each_entry_rcu(iter4, &iface->addr4_list, list)
-		if (iter4->valid)
-			goto unlhsh_condremove_failure;
-	list_for_each_entry_rcu(iter6, &iface->addr6_list, list)
-		if (iter6->valid)
-			goto unlhsh_condremove_failure;
+	netlbl_af4list_foreach_rcu(iter4, &iface->addr4_list)
+		goto unlhsh_condremove_failure;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	netlbl_af6list_foreach_rcu(iter6, &iface->addr6_list)
+		goto unlhsh_condremove_failure;
+#endif /* IPv6 */
 	iface->valid = 0;
 	if (iface->ifindex > 0)
 		list_del_rcu(&iface->list);
@@ -1349,7 +1260,7 @@
 	if (addr4) {
 		struct in_addr addr_struct;
 
-		addr_struct.s_addr = addr4->addr;
+		addr_struct.s_addr = addr4->list.addr;
 		ret_val = nla_put(cb_arg->skb,
 				  NLBL_UNLABEL_A_IPV4ADDR,
 				  sizeof(struct in_addr),
@@ -1357,7 +1268,7 @@
 		if (ret_val != 0)
 			goto list_cb_failure;
 
-		addr_struct.s_addr = addr4->mask;
+		addr_struct.s_addr = addr4->list.mask;
 		ret_val = nla_put(cb_arg->skb,
 				  NLBL_UNLABEL_A_IPV4MASK,
 				  sizeof(struct in_addr),
@@ -1370,14 +1281,14 @@
 		ret_val = nla_put(cb_arg->skb,
 				  NLBL_UNLABEL_A_IPV6ADDR,
 				  sizeof(struct in6_addr),
-				  &addr6->addr);
+				  &addr6->list.addr);
 		if (ret_val != 0)
 			goto list_cb_failure;
 
 		ret_val = nla_put(cb_arg->skb,
 				  NLBL_UNLABEL_A_IPV6MASK,
 				  sizeof(struct in6_addr),
-				  &addr6->mask);
+				  &addr6->list.mask);
 		if (ret_val != 0)
 			goto list_cb_failure;
 
@@ -1425,9 +1336,11 @@
 	u32 iter_bkt;
 	u32 iter_chain = 0, iter_addr4 = 0, iter_addr6 = 0;
 	struct netlbl_unlhsh_iface *iface;
-	struct netlbl_unlhsh_addr4 *addr4;
-	struct netlbl_unlhsh_addr6 *addr6;
 	struct list_head *iter_list;
+	struct netlbl_af4list *addr4;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	struct netlbl_af6list *addr6;
+#endif
 
 	cb_arg.nl_cb = cb;
 	cb_arg.skb = skb;
@@ -1442,38 +1355,38 @@
 			if (!iface->valid ||
 			    iter_chain++ < skip_chain)
 				continue;
-			list_for_each_entry_rcu(addr4,
-						&iface->addr4_list,
-						list) {
-				if (!addr4->valid || iter_addr4++ < skip_addr4)
+			netlbl_af4list_foreach_rcu(addr4,
+						   &iface->addr4_list) {
+				if (iter_addr4++ < skip_addr4)
 					continue;
 				if (netlbl_unlabel_staticlist_gen(
-					             NLBL_UNLABEL_C_STATICLIST,
-						     iface,
-						     addr4,
-						     NULL,
-						     &cb_arg) < 0) {
+					      NLBL_UNLABEL_C_STATICLIST,
+					      iface,
+					      netlbl_unlhsh_addr4_entry(addr4),
+					      NULL,
+					      &cb_arg) < 0) {
 					iter_addr4--;
 					iter_chain--;
 					goto unlabel_staticlist_return;
 				}
 			}
-			list_for_each_entry_rcu(addr6,
-						&iface->addr6_list,
-						list) {
-				if (!addr6->valid || iter_addr6++ < skip_addr6)
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+			netlbl_af6list_foreach_rcu(addr6,
+						   &iface->addr6_list) {
+				if (iter_addr6++ < skip_addr6)
 					continue;
 				if (netlbl_unlabel_staticlist_gen(
-						     NLBL_UNLABEL_C_STATICLIST,
-						     iface,
-						     NULL,
-						     addr6,
-						     &cb_arg) < 0) {
+					      NLBL_UNLABEL_C_STATICLIST,
+					      iface,
+					      NULL,
+					      netlbl_unlhsh_addr6_entry(addr6),
+					      &cb_arg) < 0) {
 					iter_addr6--;
 					iter_chain--;
 					goto unlabel_staticlist_return;
 				}
 			}
+#endif /* IPv6 */
 		}
 	}
 
@@ -1504,9 +1417,12 @@
 	struct netlbl_unlhsh_iface *iface;
 	u32 skip_addr4 = cb->args[0];
 	u32 skip_addr6 = cb->args[1];
-	u32 iter_addr4 = 0, iter_addr6 = 0;
-	struct netlbl_unlhsh_addr4 *addr4;
-	struct netlbl_unlhsh_addr6 *addr6;
+	u32 iter_addr4 = 0;
+	struct netlbl_af4list *addr4;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	u32 iter_addr6 = 0;
+	struct netlbl_af6list *addr6;
+#endif
 
 	cb_arg.nl_cb = cb;
 	cb_arg.skb = skb;
@@ -1517,30 +1433,32 @@
 	if (iface == NULL || !iface->valid)
 		goto unlabel_staticlistdef_return;
 
-	list_for_each_entry_rcu(addr4, &iface->addr4_list, list) {
-		if (!addr4->valid || iter_addr4++ < skip_addr4)
+	netlbl_af4list_foreach_rcu(addr4, &iface->addr4_list) {
+		if (iter_addr4++ < skip_addr4)
 			continue;
 		if (netlbl_unlabel_staticlist_gen(NLBL_UNLABEL_C_STATICLISTDEF,
-					   iface,
-					   addr4,
-					   NULL,
-					   &cb_arg) < 0) {
+					      iface,
+					      netlbl_unlhsh_addr4_entry(addr4),
+					      NULL,
+					      &cb_arg) < 0) {
 			iter_addr4--;
 			goto unlabel_staticlistdef_return;
 		}
 	}
-	list_for_each_entry_rcu(addr6, &iface->addr6_list, list) {
-		if (!addr6->valid || iter_addr6++ < skip_addr6)
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+	netlbl_af6list_foreach_rcu(addr6, &iface->addr6_list) {
+		if (iter_addr6++ < skip_addr6)
 			continue;
 		if (netlbl_unlabel_staticlist_gen(NLBL_UNLABEL_C_STATICLISTDEF,
-					   iface,
-					   NULL,
-					   addr6,
-					   &cb_arg) < 0) {
+					      iface,
+					      NULL,
+					      netlbl_unlhsh_addr6_entry(addr6),
+					      &cb_arg) < 0) {
 			iter_addr6--;
 			goto unlabel_staticlistdef_return;
 		}
 	}
+#endif /* IPv6 */
 
 unlabel_staticlistdef_return:
 	rcu_read_unlock();
@@ -1718,25 +1636,27 @@
 	switch (family) {
 	case PF_INET: {
 		struct iphdr *hdr4;
-		struct netlbl_unlhsh_addr4 *addr4;
+		struct netlbl_af4list *addr4;
 
 		hdr4 = ip_hdr(skb);
-		addr4 = netlbl_unlhsh_search_addr4(hdr4->saddr, iface);
+		addr4 = netlbl_af4list_search(hdr4->saddr,
+					      &iface->addr4_list);
 		if (addr4 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = addr4->secid;
+		secattr->attr.secid = netlbl_unlhsh_addr4_entry(addr4)->secid;
 		break;
 	}
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case PF_INET6: {
 		struct ipv6hdr *hdr6;
-		struct netlbl_unlhsh_addr6 *addr6;
+		struct netlbl_af6list *addr6;
 
 		hdr6 = ipv6_hdr(skb);
-		addr6 = netlbl_unlhsh_search_addr6(&hdr6->saddr, iface);
+		addr6 = netlbl_af6list_search(&hdr6->saddr,
+					      &iface->addr6_list);
 		if (addr6 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = addr6->secid;
+		secattr->attr.secid = netlbl_unlhsh_addr6_entry(addr6)->secid;
 		break;
 	}
 #endif /* IPv6 */