Imported Upstream version 1.24
[platform/upstream/connman.git] / src / iptables.c
index 9584e12..8d583ea 100644 (file)
@@ -2,7 +2,7 @@
  *
  *  Connection Manager
  *
- *  Copyright (C) 2007-2012  Intel Corporation. All rights reserved.
+ *  Copyright (C) 2007-2013  Intel Corporation. All rights reserved.
  *
  *  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
@@ -35,6 +35,7 @@
 #include <linux/netfilter_ipv4/ip_tables.h>
 
 #include "connman.h"
+#include "src/shared/util.h"
 
 /*
  * Some comments on how the iptables API works (some of them from the
@@ -175,10 +176,10 @@ struct connman_iptables {
 };
 
 static GHashTable *table_hash = NULL;
-static gboolean debug_enabled = FALSE;
+static bool debug_enabled = false;
 
 typedef int (*iterate_entries_cb_t)(struct ipt_entry *entry, int builtin,
-                                       unsigned int hook,size_t size,
+                                       unsigned int hook, size_t size,
                                        unsigned int offset, void *user_data);
 
 static unsigned int next_hook_entry_index(unsigned int *valid_hooks)
@@ -233,9 +234,8 @@ static int iterate_entries(struct ipt_entry *entries,
                if (h == NF_INET_NUMHOOKS)
                        hook = h;
 
-               if (h < NF_INET_NUMHOOKS && underflow[h] <= offset) {
+               if (h < NF_INET_NUMHOOKS && underflow[h] <= offset)
                        h = next_hook_entry_index(&valid_hooks);
-               }
 
                err = cb(entry, builtin, hook, size, offset, user_data);
                if (err < 0)
@@ -274,18 +274,18 @@ static int target_to_verdict(const char *target_name)
        return 0;
 }
 
-static gboolean is_builtin_target(const char *target_name)
+static bool is_builtin_target(const char *target_name)
 {
        if (!g_strcmp0(target_name, LABEL_ACCEPT) ||
                !g_strcmp0(target_name, LABEL_DROP) ||
                !g_strcmp0(target_name, LABEL_QUEUE) ||
                !g_strcmp0(target_name, LABEL_RETURN))
-               return TRUE;
+               return true;
 
-       return FALSE;
+       return false;
 }
 
-static gboolean is_jump(struct connman_iptables_entry *e)
+static bool is_jump(struct connman_iptables_entry *e)
 {
        struct xt_entry_target *target;
 
@@ -312,7 +312,7 @@ static gboolean is_jump(struct connman_iptables_entry *e)
        return false;
 }
 
-static gboolean is_fallthrough(struct connman_iptables_entry *e)
+static bool is_fallthrough(struct connman_iptables_entry *e)
 {
        struct xt_entry_target *target;
 
@@ -327,7 +327,7 @@ static gboolean is_fallthrough(struct connman_iptables_entry *e)
        return false;
 }
 
-static gboolean is_chain(struct connman_iptables *table,
+static bool is_chain(struct connman_iptables *table,
                                struct connman_iptables_entry *e)
 {
        struct ipt_entry *entry;
@@ -335,13 +335,13 @@ static gboolean is_chain(struct connman_iptables *table,
 
        entry = e->entry;
        if (e->builtin >= 0)
-               return TRUE;
+               return true;
 
        target = ipt_get_target(entry);
        if (!g_strcmp0(target->u.user.name, IPT_ERROR_TARGET))
-               return TRUE;
+               return true;
 
-       return FALSE;
+       return false;
 }
 
 static GList *find_chain_head(struct connman_iptables *table,
@@ -379,7 +379,7 @@ static GList *find_chain_tail(struct connman_iptables *table,
        GList *chain_head, *list;
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return NULL;
 
        /* Then we look for the next chain */
@@ -420,7 +420,7 @@ static void update_offsets(struct connman_iptables *table)
 static void update_targets_reference(struct connman_iptables *table,
                                struct connman_iptables_entry *entry_before,
                                struct connman_iptables_entry *modified_entry,
-                               gboolean is_removing)
+                               bool is_removing)
 {
        struct connman_iptables_entry *tmp;
        struct xt_standard_target *t;
@@ -437,7 +437,7 @@ static void update_targets_reference(struct connman_iptables *table,
 
                t = (struct xt_standard_target *)ipt_get_target(tmp->entry);
 
-               if (is_removing == TRUE) {
+               if (is_removing) {
                        if (t->verdict >= entry_before->offset)
                                t->verdict -= offset;
                } else {
@@ -447,7 +447,8 @@ static void update_targets_reference(struct connman_iptables *table,
        }
 
        if (is_fallthrough(modified_entry)) {
-               t = (struct xt_standard_target *) ipt_get_target(modified_entry->entry);
+               t = (struct xt_standard_target *)
+                       ipt_get_target(modified_entry->entry);
 
                t->verdict = entry_before->offset +
                        modified_entry->entry->target_offset +
@@ -463,11 +464,11 @@ static int iptables_add_entry(struct connman_iptables *table,
 {
        struct connman_iptables_entry *e, *entry_before;
 
-       if (table == NULL)
+       if (!table)
                return -1;
 
        e = g_try_malloc0(sizeof(struct connman_iptables_entry));
-       if (e == NULL)
+       if (!e)
                return -1;
 
        e->entry = entry;
@@ -477,7 +478,7 @@ static int iptables_add_entry(struct connman_iptables *table,
        table->num_entries++;
        table->size += entry->next_offset;
 
-       if (before == NULL) {
+       if (!before) {
                e->offset = table->size - entry->next_offset;
 
                return 0;
@@ -489,7 +490,7 @@ static int iptables_add_entry(struct connman_iptables *table,
         * We've just appended/insterted a new entry. All references
         * should be bumped accordingly.
         */
-       update_targets_reference(table, entry_before, e, FALSE);
+       update_targets_reference(table, entry_before, e, false);
 
        update_offsets(table);
 
@@ -546,11 +547,11 @@ static int iptables_flush_chain(struct connman_iptables *table,
        DBG("table %s chain %s", table->name, name);
 
        chain_head = find_chain_head(table, name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return -EINVAL;
 
        chain_tail = find_chain_tail(table, name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return -EINVAL;
 
        entry = chain_head->data;
@@ -605,13 +606,13 @@ static int iptables_add_chain(struct connman_iptables *table,
         */
 
        /* head entry */
-       entry_head_size = sizeof(struct ipt_entry) +
-                               sizeof(struct error_target);
+       entry_head_size = ALIGN(sizeof(struct ipt_entry)) +
+                       ALIGN(sizeof(struct error_target));
        entry_head = g_try_malloc0(entry_head_size);
-       if (entry_head == NULL)
+       if (!entry_head)
                goto err_head;
 
-       entry_head->target_offset = sizeof(struct ipt_entry);
+       entry_head->target_offset = ALIGN(sizeof(struct ipt_entry));
        entry_head->next_offset = entry_head_size;
 
        error = (struct error_target *) entry_head->elems;
@@ -623,13 +624,13 @@ static int iptables_add_chain(struct connman_iptables *table,
                goto err_head;
 
        /* tail entry */
-       entry_return_size = sizeof(struct ipt_entry) +
-                               sizeof(struct ipt_standard_target);
+       entry_return_size = ALIGN(sizeof(struct ipt_entry))+
+                       ALIGN(sizeof(struct ipt_standard_target));
        entry_return = g_try_malloc0(entry_return_size);
-       if (entry_return == NULL)
+       if (!entry_return)
                goto err;
 
-       entry_return->target_offset = sizeof(struct ipt_entry);
+       entry_return->target_offset = ALIGN(sizeof(struct ipt_entry));
        entry_return->next_offset = entry_return_size;
 
        standard = (struct ipt_standard_target *) entry_return->elems;
@@ -659,7 +660,7 @@ static int iptables_delete_chain(struct connman_iptables *table,
        DBG("table %s chain %s", table->name, name);
 
        chain_head = find_chain_head(table, name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return -EINVAL;
 
        entry = chain_head->data;
@@ -669,7 +670,7 @@ static int iptables_delete_chain(struct connman_iptables *table,
                return -EINVAL;
 
        chain_tail = find_chain_tail(table, name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return -EINVAL;
 
        /* Chain must be flushed */
@@ -695,27 +696,28 @@ static struct ipt_entry *new_rule(struct ipt_ip *ip,
        size_t match_size, target_size;
 
        match_size = 0;
-       for (tmp_xt_rm = xt_rm; tmp_xt_rm != NULL; tmp_xt_rm = tmp_xt_rm->next)
+       for (tmp_xt_rm = xt_rm; tmp_xt_rm; tmp_xt_rm = tmp_xt_rm->next)
                match_size += tmp_xt_rm->match->m->u.match_size;
 
        if (xt_t)
-               target_size = ALIGN(xt_t->t->u.target_size);
+               target_size = xt_t->t->u.target_size;
        else
                target_size = ALIGN(sizeof(struct xt_standard_target));
 
-       new_entry = g_try_malloc0(sizeof(struct ipt_entry) + target_size +
-                                                               match_size);
-       if (new_entry == NULL)
+       new_entry = g_try_malloc0(ALIGN(sizeof(struct ipt_entry)) +
+                               target_size + match_size);
+       if (!new_entry)
                return NULL;
 
        memcpy(&new_entry->ip, ip, sizeof(struct ipt_ip));
 
-       new_entry->target_offset = sizeof(struct ipt_entry) + match_size;
-       new_entry->next_offset = sizeof(struct ipt_entry) + target_size +
-                                                               match_size;
+       new_entry->target_offset = ALIGN(sizeof(struct ipt_entry)) +
+                                                       match_size;
+       new_entry->next_offset = ALIGN(sizeof(struct ipt_entry)) +
+                                       target_size + match_size;
 
        match_size = 0;
-       for (tmp_xt_rm = xt_rm; tmp_xt_rm != NULL;
+       for (tmp_xt_rm = xt_rm; tmp_xt_rm;
                                tmp_xt_rm = tmp_xt_rm->next) {
                memcpy(new_entry->elems + match_size, tmp_xt_rm->match->m,
                                        tmp_xt_rm->match->m->u.match_size);
@@ -739,7 +741,7 @@ static void update_hooks(struct connman_iptables *table, GList *chain_head,
        struct connman_iptables_entry *head, *e;
        int builtin;
 
-       if (chain_head == NULL)
+       if (!chain_head)
                return;
 
        head = chain_head->data;
@@ -767,22 +769,22 @@ static struct ipt_entry *prepare_rule_inclusion(struct connman_iptables *table,
                                const char *target_name,
                                struct xtables_target *xt_t,
                                int *builtin, struct xtables_rule_match *xt_rm,
-                               connman_bool_t insert)
+                               bool insert)
 {
        GList *chain_tail, *chain_head;
        struct ipt_entry *new_entry;
        struct connman_iptables_entry *head;
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return NULL;
 
        chain_tail = find_chain_tail(table, chain_name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return NULL;
 
        new_entry = new_rule(ip, target_name, xt_t, xt_rm);
-       if (new_entry == NULL)
+       if (!new_entry)
                return NULL;
 
        update_hooks(table, chain_head, new_entry);
@@ -795,7 +797,7 @@ static struct ipt_entry *prepare_rule_inclusion(struct connman_iptables *table,
        head = chain_head->data;
        if (head->builtin < 0)
                *builtin = -1;
-       else if (insert == TRUE || chain_head == chain_tail->prev) {
+       else if (insert || chain_head == chain_tail->prev) {
                *builtin = head->builtin;
                head->builtin = -1;
        }
@@ -816,12 +818,12 @@ static int iptables_append_rule(struct connman_iptables *table,
        DBG("table %s chain %s", table->name, chain_name);
 
        chain_tail = find_chain_tail(table, chain_name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return -EINVAL;
 
        new_entry = prepare_rule_inclusion(table, ip, chain_name,
-                               target_name, xt_t, &builtin, xt_rm, FALSE);
-       if (new_entry == NULL)
+                               target_name, xt_t, &builtin, xt_rm, false);
+       if (!new_entry)
                return -EINVAL;
 
        ret = iptables_add_entry(table, new_entry, chain_tail->prev, builtin);
@@ -844,12 +846,12 @@ static int iptables_insert_rule(struct connman_iptables *table,
        DBG("table %s chain %s", table->name, chain_name);
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return -EINVAL;
 
        new_entry = prepare_rule_inclusion(table, ip, chain_name,
-                               target_name, xt_t, &builtin, xt_rm, TRUE);
-       if (new_entry == NULL)
+                               target_name, xt_t, &builtin, xt_rm, true);
+       if (!new_entry)
                return -EINVAL;
 
        if (builtin == -1)
@@ -862,33 +864,33 @@ static int iptables_insert_rule(struct connman_iptables *table,
        return ret;
 }
 
-static gboolean is_same_ipt_entry(struct ipt_entry *i_e1,
+static bool is_same_ipt_entry(struct ipt_entry *i_e1,
                                        struct ipt_entry *i_e2)
 {
        if (memcmp(&i_e1->ip, &i_e2->ip, sizeof(struct ipt_ip)) != 0)
-               return FALSE;
+               return false;
 
        if (i_e1->target_offset != i_e2->target_offset)
-               return FALSE;
+               return false;
 
        if (i_e1->next_offset != i_e2->next_offset)
-               return FALSE;
+               return false;
 
-       return TRUE;
+       return true;
 }
 
-static gboolean is_same_target(struct xt_entry_target *xt_e_t1,
+static bool is_same_target(struct xt_entry_target *xt_e_t1,
                                        struct xt_entry_target *xt_e_t2)
 {
        unsigned int i;
 
-       if (xt_e_t1 == NULL || xt_e_t2 == NULL)
-               return FALSE;
+       if (!xt_e_t1 || !xt_e_t2)
+               return false;
 
        if (g_strcmp0(xt_e_t1->u.user.name, "") == 0 &&
                        g_strcmp0(xt_e_t2->u.user.name, "") == 0) {
                /* fallthrough */
-               return TRUE;
+               return true;
        } else if (g_strcmp0(xt_e_t1->u.user.name, IPT_STANDARD_TARGET) == 0) {
                struct xt_standard_target *xt_s_t1;
                struct xt_standard_target *xt_s_t2;
@@ -897,48 +899,48 @@ static gboolean is_same_target(struct xt_entry_target *xt_e_t1,
                xt_s_t2 = (struct xt_standard_target *) xt_e_t2;
 
                if (xt_s_t1->verdict != xt_s_t2->verdict)
-                       return FALSE;
+                       return false;
        } else {
                if (xt_e_t1->u.target_size != xt_e_t2->u.target_size)
-                       return FALSE;
+                       return false;
 
                if (g_strcmp0(xt_e_t1->u.user.name, xt_e_t2->u.user.name) != 0)
-                       return FALSE;
+                       return false;
 
                for (i = 0; i < xt_e_t1->u.target_size -
                                sizeof(struct xt_standard_target); i++) {
                        if ((xt_e_t1->data[i] ^ xt_e_t2->data[i]) != 0)
-                               return FALSE;
+                               return false;
                }
        }
 
-       return TRUE;
+       return true;
 }
 
-static gboolean is_same_match(struct xt_entry_match *xt_e_m1,
+static bool is_same_match(struct xt_entry_match *xt_e_m1,
                                struct xt_entry_match *xt_e_m2)
 {
        unsigned int i;
 
-       if (xt_e_m1 == NULL || xt_e_m2 == NULL)
-               return FALSE;
+       if (!xt_e_m1 || !xt_e_m2)
+               return false;
 
        if (xt_e_m1->u.match_size != xt_e_m2->u.match_size)
-               return FALSE;
+               return false;
 
        if (xt_e_m1->u.user.revision != xt_e_m2->u.user.revision)
-               return FALSE;
+               return false;
 
        if (g_strcmp0(xt_e_m1->u.user.name, xt_e_m2->u.user.name) != 0)
-               return FALSE;
+               return false;
 
        for (i = 0; i < xt_e_m1->u.match_size - sizeof(struct xt_entry_match);
                        i++) {
                if ((xt_e_m1->data[i] ^ xt_e_m2->data[i]) != 0)
-                       return FALSE;
+                       return false;
        }
 
-       return TRUE;
+       return true;
 }
 
 static GList *find_existing_rule(struct connman_iptables *table,
@@ -956,23 +958,23 @@ static GList *find_existing_rule(struct connman_iptables *table,
        int builtin;
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return NULL;
 
        chain_tail = find_chain_tail(table, chain_name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return NULL;
 
        if (!xt_t && !matches)
                return NULL;
 
        entry_test = new_rule(ip, target_name, xt_t, xt_rm);
-       if (entry_test == NULL)
+       if (!entry_test)
                return NULL;
 
-       if (xt_t != NULL)
+       if (xt_t)
                xt_e_t = ipt_get_target(entry_test);
-       if (matches != NULL)
+       if (matches)
                xt_e_m = (struct xt_entry_match *)entry_test->elems;
 
        entry = chain_head->data;
@@ -990,10 +992,10 @@ static GList *find_existing_rule(struct connman_iptables *table,
                tmp = list->data;
                tmp_e = tmp->entry;
 
-               if (is_same_ipt_entry(entry_test, tmp_e) == FALSE)
+               if (!is_same_ipt_entry(entry_test, tmp_e))
                        continue;
 
-               if (xt_t != NULL) {
+               if (xt_t) {
                        struct xt_entry_target *tmp_xt_e_t;
 
                        tmp_xt_e_t = ipt_get_target(tmp_e);
@@ -1002,7 +1004,7 @@ static GList *find_existing_rule(struct connman_iptables *table,
                                continue;
                }
 
-               if (matches != NULL) {
+               if (matches) {
                        struct xt_entry_match *tmp_xt_e_m;
 
                        tmp_xt_e_m = (struct xt_entry_match *)tmp_e->elems;
@@ -1039,16 +1041,16 @@ static int iptables_delete_rule(struct connman_iptables *table,
        removed = 0;
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return -EINVAL;
 
        chain_tail = find_chain_tail(table, chain_name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return -EINVAL;
 
        list = find_existing_rule(table, ip, chain_name, target_name,
                                                        xt_t, matches, xt_rm);
-       if (list == NULL)
+       if (!list)
                return -EINVAL;
 
        entry = chain_head->data;
@@ -1071,14 +1073,14 @@ static int iptables_delete_rule(struct connman_iptables *table,
        }
 
        entry = list->data;
-       if (entry == NULL)
+       if (!entry)
                return -EINVAL;
 
        /* We have deleted a rule,
         * all references should be bumped accordingly */
-       if (list->next != NULL)
+       if (list->next)
                update_targets_reference(table, list->next->data,
-                                               list->data, TRUE);
+                                               list->data, true);
 
        removed += remove_table_entry(table, entry);
 
@@ -1111,7 +1113,7 @@ static int iptables_change_policy(struct connman_iptables *table,
        }
 
        chain_head = find_chain_head(table, chain_name);
-       if (chain_head == NULL)
+       if (!chain_head)
                return -EINVAL;
 
        entry = chain_head->data;
@@ -1119,7 +1121,7 @@ static int iptables_change_policy(struct connman_iptables *table,
                return -EINVAL;
 
        chain_tail = find_chain_tail(table, chain_name);
-       if (chain_tail == NULL)
+       if (!chain_tail)
                return -EINVAL;
 
        entry = chain_tail->prev->data;
@@ -1139,14 +1141,14 @@ static struct ipt_replace *iptables_blob(struct connman_iptables *table)
        unsigned char *entry_index;
 
        r = g_try_malloc0(sizeof(struct ipt_replace) + table->size);
-       if (r == NULL)
+       if (!r)
                return NULL;
 
        memset(r, 0, sizeof(*r) + table->size);
 
        r->counters = g_try_malloc0(sizeof(struct xt_counters)
                                * table->old_entries);
-       if (r->counters == NULL) {
+       if (!r->counters) {
                g_free(r);
                return NULL;
        }
@@ -1184,14 +1186,14 @@ static void dump_ip(struct ipt_entry *entry)
        if (strlen(ip->outiface))
                DBG("\tout %s", ip->outiface);
 
-       if (inet_ntop(AF_INET, &ip->src, ip_string, INET6_ADDRSTRLEN) != NULL &&
-                       inet_ntop(AF_INET, &ip->smsk,
-                                       ip_mask, INET6_ADDRSTRLEN) != NULL)
+       if (inet_ntop(AF_INET, &ip->src, ip_string, INET6_ADDRSTRLEN) &&
+                       inet_ntop(AF_INET, &ip->smsk, ip_mask,
+                               INET6_ADDRSTRLEN))
                DBG("\tsrc %s/%s", ip_string, ip_mask);
 
-       if (inet_ntop(AF_INET, &ip->dst, ip_string, INET6_ADDRSTRLEN) != NULL &&
-                       inet_ntop(AF_INET, &ip->dmsk,
-                                       ip_mask, INET6_ADDRSTRLEN) != NULL)
+       if (inet_ntop(AF_INET, &ip->dst, ip_string, INET6_ADDRSTRLEN) &&
+                       inet_ntop(AF_INET, &ip->dmsk, ip_mask,
+                               INET6_ADDRSTRLEN))
                DBG("\tdst %s/%s", ip_string, ip_mask);
 }
 
@@ -1237,16 +1239,16 @@ static void dump_target(struct ipt_entry *entry)
                xt_t = xtables_find_target(IPT_STANDARD_TARGET,
                                                XTF_LOAD_MUST_SUCCEED);
 
-               if(xt_t->print != NULL)
+               if (xt_t->print)
                        xt_t->print(NULL, target, 1);
        } else {
                xt_t = xtables_find_target(target->u.user.name, XTF_TRY_LOAD);
-               if (xt_t == NULL) {
+               if (!xt_t) {
                        DBG("\ttarget %s", target->u.user.name);
                        return;
                }
 
-               if(xt_t->print != NULL) {
+               if (xt_t->print) {
                        DBG("\ttarget ");
                        xt_t->print(NULL, target, 1);
                }
@@ -1270,10 +1272,10 @@ static void dump_match(struct ipt_entry *entry)
                return;
 
        xt_m = xtables_find_match(match->u.user.name, XTF_TRY_LOAD, NULL);
-       if (xt_m == NULL)
+       if (!xt_m)
                goto out;
 
-       if(xt_m->print != NULL) {
+       if (xt_m->print) {
                DBG("\tmatch ");
                xt_m->print(NULL, match, 1);
 
@@ -1378,18 +1380,29 @@ static void dump_ipt_replace(struct ipt_replace *repl)
 static int iptables_get_entries(struct connman_iptables *table)
 {
        socklen_t entry_size;
+       int err;
 
        entry_size = sizeof(struct ipt_get_entries) + table->info->size;
 
-       return getsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_GET_ENTRIES,
+       err = getsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_GET_ENTRIES,
                                table->blob_entries, &entry_size);
+       if (err < 0)
+               return -errno;
+
+       return 0;
 }
 
 static int iptables_replace(struct connman_iptables *table,
                                        struct ipt_replace *r)
 {
-       return setsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_SET_REPLACE, r,
-                        sizeof(*r) + r->size);
+       int err;
+
+       err = setsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_SET_REPLACE, r,
+                       sizeof(*r) + r->size);
+       if (err < 0)
+               return -errno;
+
+       return 0;
 }
 
 static int add_entry(struct ipt_entry *entry, int builtin, unsigned int hook,
@@ -1399,7 +1412,7 @@ static int add_entry(struct ipt_entry *entry, int builtin, unsigned int hook,
        struct ipt_entry *new_entry;
 
        new_entry = g_try_malloc0(entry->next_offset);
-       if (new_entry == NULL)
+       if (!new_entry)
                return -ENOMEM;
 
        memcpy(new_entry, entry, entry->next_offset);
@@ -1412,7 +1425,7 @@ static void table_cleanup(struct connman_iptables *table)
        GList *list;
        struct connman_iptables_entry *entry;
 
-       if (table == NULL)
+       if (!table)
                return;
 
        if (table->ipt_sock >= 0)
@@ -1444,7 +1457,7 @@ static struct connman_iptables *iptables_init(const char *table_name)
                DBG("ip_tables module loading gives error but trying anyway");
 
        module = g_strconcat("iptable_", table_name, NULL);
-       if (module == NULL)
+       if (!module)
                return NULL;
 
        if (xtables_insmod(module, NULL, TRUE) != 0)
@@ -1453,11 +1466,11 @@ static struct connman_iptables *iptables_init(const char *table_name)
        g_free(module);
 
        table = g_try_new0(struct connman_iptables, 1);
-       if (table == NULL)
+       if (!table)
                return NULL;
 
        table->info = g_try_new0(struct ipt_getinfo, 1);
-       if (table->info == NULL)
+       if (!table->info)
                goto err;
 
        table->ipt_sock = socket(AF_INET, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_RAW);
@@ -1475,7 +1488,7 @@ static struct connman_iptables *iptables_init(const char *table_name)
 
        table->blob_entries = g_try_malloc0(sizeof(struct ipt_get_entries) +
                                                table->info->size);
-       if (table->blob_entries == NULL)
+       if (!table->blob_entries)
                goto err;
 
        g_stpcpy(table->blob_entries->name, table_name);
@@ -1498,7 +1511,7 @@ static struct connman_iptables *iptables_init(const char *table_name)
                        table->info->underflow, table->blob_entries->size,
                        add_entry, table);
 
-       if (debug_enabled == TRUE)
+       if (debug_enabled)
                dump_table(table);
 
        return table;
@@ -1539,19 +1552,19 @@ static struct xtables_target *prepare_target(struct connman_iptables *table,
                                                        const char *target_name)
 {
        struct xtables_target *xt_t = NULL;
-       gboolean is_builtin, is_user_defined;
+       bool is_builtin, is_user_defined;
        GList *chain_head = NULL;
        size_t target_size;
 
-       is_builtin = FALSE;
-       is_user_defined = FALSE;
+       is_builtin = false;
+       is_user_defined = false;
 
        if (is_builtin_target(target_name))
-               is_builtin = TRUE;
+               is_builtin = true;
        else {
                chain_head = find_chain_head(table, target_name);
-               if (chain_head != NULL && chain_head->next != NULL)
-                       is_user_defined = TRUE;
+               if (chain_head && chain_head->next)
+                       is_user_defined = true;
        }
 
        if (is_builtin || is_user_defined)
@@ -1560,13 +1573,13 @@ static struct xtables_target *prepare_target(struct connman_iptables *table,
        else
                xt_t = xtables_find_target(target_name, XTF_TRY_LOAD);
 
-       if (xt_t == NULL)
+       if (!xt_t)
                return NULL;
 
        target_size = ALIGN(sizeof(struct ipt_entry_target)) + xt_t->size;
 
        xt_t->t = g_try_malloc0(target_size);
-       if (xt_t->t == NULL)
+       if (!xt_t->t)
                return NULL;
 
        xt_t->t->u.target_size = target_size;
@@ -1577,27 +1590,22 @@ static struct xtables_target *prepare_target(struct connman_iptables *table,
                target = (struct xt_standard_target *)(xt_t->t);
                g_stpcpy(target->target.u.user.name, IPT_STANDARD_TARGET);
 
-               if (is_builtin == TRUE)
+               if (is_builtin)
                        target->verdict = target_to_verdict(target_name);
-               else if (is_user_defined == TRUE) {
+               else if (is_user_defined) {
                        struct connman_iptables_entry *target_rule;
 
-                       if (chain_head == NULL) {
-                               g_free(xt_t->t);
-                               return NULL;
-                       }
-
                        target_rule = chain_head->next->data;
                        target->verdict = target_rule->offset;
                }
        } else {
                g_stpcpy(xt_t->t->u.user.name, target_name);
                xt_t->t->u.user.revision = xt_t->revision;
-               if (xt_t->init != NULL)
+               if (xt_t->init)
                        xt_t->init(xt_t->t);
        }
 
-       if (xt_t->x6_options != NULL)
+       if (xt_t->x6_options)
                iptables_globals.opts =
                        xtables_options_xfrm(
                                iptables_globals.orig_opts,
@@ -1612,7 +1620,7 @@ static struct xtables_target *prepare_target(struct connman_iptables *table,
                                xt_t->extra_opts,
                                &xt_t->option_offset);
 
-       if (iptables_globals.opts == NULL) {
+       if (!iptables_globals.opts) {
                g_free(xt_t->t);
                xt_t = NULL;
        }
@@ -1627,24 +1635,24 @@ static struct xtables_match *prepare_matches(struct connman_iptables *table,
        struct xtables_match *xt_m;
        size_t match_size;
 
-       if (match_name == NULL)
+       if (!match_name)
                return NULL;
 
        xt_m = xtables_find_match(match_name, XTF_LOAD_MUST_SUCCEED, xt_rm);
        match_size = ALIGN(sizeof(struct ipt_entry_match)) + xt_m->size;
 
        xt_m->m = g_try_malloc0(match_size);
-       if (xt_m->m == NULL)
+       if (!xt_m->m)
                return NULL;
 
        xt_m->m->u.match_size = match_size;
        g_stpcpy(xt_m->m->u.user.name, xt_m->name);
        xt_m->m->u.user.revision = xt_m->revision;
 
-       if (xt_m->init != NULL)
+       if (xt_m->init)
                xt_m->init(xt_m->m);
 
-       if (xt_m->x6_options != NULL)
+       if (xt_m->x6_options)
                iptables_globals.opts =
                        xtables_options_xfrm(
                                iptables_globals.orig_opts,
@@ -1659,7 +1667,7 @@ static struct xtables_match *prepare_matches(struct connman_iptables *table,
                                xt_m->extra_opts,
                                &xt_m->option_offset);
 
-       if (iptables_globals.opts == NULL) {
+       if (!iptables_globals.opts) {
                g_free(xt_m->m);
 
                if (xt_m == xt_m->next)
@@ -1671,7 +1679,8 @@ static struct xtables_match *prepare_matches(struct connman_iptables *table,
        return xt_m;
 }
 
-static int parse_ip_and_mask(const char *str, struct in_addr *ip, struct in_addr *mask)
+static int parse_ip_and_mask(const char *str, struct in_addr *ip,
+                               struct in_addr *mask)
 {
        char **tokens;
        uint32_t prefixlength;
@@ -1679,7 +1688,7 @@ static int parse_ip_and_mask(const char *str, struct in_addr *ip, struct in_addr
        int err;
 
        tokens = g_strsplit(str, "/", 2);
-       if (tokens == NULL)
+       if (!tokens)
                return -1;
 
        if (!inet_pton(AF_INET, tokens[0], ip)) {
@@ -1687,7 +1696,7 @@ static int parse_ip_and_mask(const char *str, struct in_addr *ip, struct in_addr
                goto out;
        }
 
-       if (tokens[1] != NULL) {
+       if (tokens[1]) {
                prefixlength = strtol(tokens[1], NULL, 10);
                if (prefixlength > 31) {
                        err = -1;
@@ -1712,15 +1721,15 @@ static struct connman_iptables *get_table(const char *table_name)
 {
        struct connman_iptables *table;
 
-       if (table_name == NULL)
+       if (!table_name)
                table_name = "filter";
 
        table = g_hash_table_lookup(table_hash, table_name);
-       if (table != NULL)
+       if (table)
                return table;
 
        table = iptables_init(table_name);
-       if (table == NULL)
+       if (!table)
                return NULL;
 
        table->name = g_strdup(table_name);
@@ -1752,7 +1761,7 @@ static int prepare_getopt_args(const char *str, struct parse_context *ctx)
 
        /* Don't forget the last NULL entry */
        ctx->argv = g_try_malloc0((ctx->argc + 1) * sizeof(char *));
-       if (ctx->argv == NULL) {
+       if (!ctx->argv) {
                g_strfreev(tokens);
                return -ENOMEM;
        }
@@ -1770,19 +1779,19 @@ static int prepare_getopt_args(const char *str, struct parse_context *ctx)
        return 0;
 }
 
-static int parse_xt_modules(int c, connman_bool_t invert,
+static int parse_xt_modules(int c, bool invert,
                                struct parse_context *ctx)
 {
        struct xtables_match *m;
        struct xtables_rule_match *rm;
 
-       for (rm = ctx->xt_rm; rm != NULL; rm = rm->next) {
+       for (rm = ctx->xt_rm; rm; rm = rm->next) {
                if (rm->completed != 0)
                        continue;
 
                m = rm->match;
 
-               if (m->x6_parse == NULL && m->parse == NULL)
+               if (!m->x6_parse && !m->parse)
                        continue;
 
                if (c < (int) m->option_offset ||
@@ -1793,10 +1802,10 @@ static int parse_xt_modules(int c, connman_bool_t invert,
                xtables_option_mpcall(c, ctx->argv, invert, m, NULL);
        }
 
-       if (ctx->xt_t == NULL)
+       if (!ctx->xt_t)
                return 0;
 
-       if (ctx->xt_t->x6_parse == NULL && ctx->xt_t->parse == NULL)
+       if (!ctx->xt_t->x6_parse && !ctx->xt_t->parse)
                return 0;
 
        if (c < (int) ctx->xt_t->option_offset ||
@@ -1813,10 +1822,10 @@ static int final_check_xt_modules(struct parse_context *ctx)
 {
        struct xtables_rule_match *rm;
 
-       for (rm = ctx->xt_rm; rm != NULL; rm = rm->next)
+       for (rm = ctx->xt_rm; rm; rm = rm->next)
                xtables_option_mfcall(rm->match);
 
-       if (ctx->xt_t != NULL)
+       if (ctx->xt_t)
                xtables_option_tfcall(ctx->xt_t);
 
        return 0;
@@ -1902,11 +1911,11 @@ static int parse_rule_spec(struct connman_iptables *table,
         *    of libxtables is found.
         */
        struct xtables_match *xt_m;
-       connman_bool_t invert = FALSE;
+       bool invert = false;
        int len, c, err;
 
        ctx->ip = g_try_new0(struct ipt_ip, 1);
-       if (ctx->ip == NULL)
+       if (!ctx->ip)
                return -ENOMEM;
 
        /*
@@ -1972,7 +1981,7 @@ static int parse_rule_spec(struct connman_iptables *table,
                case 'm':
                        /* Matches */
                        xt_m = prepare_matches(table, &ctx->xt_rm, optarg);
-                       if (xt_m == NULL) {
+                       if (!xt_m) {
                                err = -EINVAL;
                                goto out;
                        }
@@ -1982,7 +1991,7 @@ static int parse_rule_spec(struct connman_iptables *table,
                case 'j':
                        /* Target */
                        ctx->xt_t = prepare_target(table, optarg);
-                       if (ctx->xt_t == NULL) {
+                       if (!ctx->xt_t) {
                                err = -EINVAL;
                                goto out;
                        }
@@ -1990,7 +1999,7 @@ static int parse_rule_spec(struct connman_iptables *table,
                        break;
                case 1:
                        if (optarg[0] == '!' && optarg[1] == '\0') {
-                               invert = TRUE;
+                               invert = true;
 
                                /* Remove the '!' from the optarg */
                                optarg[0] = '\0';
@@ -2011,7 +2020,7 @@ static int parse_rule_spec(struct connman_iptables *table,
                        break;
                }
 
-               invert = FALSE;
+               invert = false;
        }
 
        err = final_check_xt_modules(ctx);
@@ -2033,10 +2042,10 @@ static void reset_xtables(void)
         * Clear all flags because the flags are only valid
         * for one rule.
         */
-       for (xt_m = xtables_matches; xt_m != NULL; xt_m = xt_m->next)
+       for (xt_m = xtables_matches; xt_m; xt_m = xt_m->next)
                xt_m->mflags = 0;
 
-       for (xt_t = xtables_targets; xt_t != NULL; xt_t = xt_t->next) {
+       for (xt_t = xtables_targets; xt_t; xt_t = xt_t->next) {
                xt_t->tflags = 0;
                xt_t->used = 0;
        }
@@ -2060,12 +2069,12 @@ static void cleanup_parse_context(struct parse_context *ctx)
 
        g_strfreev(ctx->argv);
        g_free(ctx->ip);
-       if (ctx->xt_t != NULL) {
+       if (ctx->xt_t) {
                g_free(ctx->xt_t->t);
                ctx->xt_t->t = NULL;
        }
 
-       for (list = ctx->xt_m; list != NULL; list = list->next) {
+       for (list = ctx->xt_m; list; list = list->next) {
                struct xtables_match *xt_m = list->data;
 
                g_free(xt_m->m);
@@ -2077,8 +2086,8 @@ static void cleanup_parse_context(struct parse_context *ctx)
        }
        g_list_free(ctx->xt_m);
 
-       for (tmp = NULL, rm = ctx->xt_rm; rm != NULL; rm = rm->next) {
-               if (tmp != NULL)
+       for (tmp = NULL, rm = ctx->xt_rm; rm; rm = rm->next) {
+               if (tmp)
                        g_free(tmp);
                tmp = rm;
        }
@@ -2094,7 +2103,7 @@ int __connman_iptables_dump(const char *table_name)
        DBG("-t %s -L", table_name);
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        dump_table(table);
@@ -2110,7 +2119,7 @@ int __connman_iptables_new_chain(const char *table_name,
        DBG("-t %s -N %s", table_name, chain);
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        return iptables_add_chain(table, chain);
@@ -2124,7 +2133,7 @@ int __connman_iptables_delete_chain(const char *table_name,
        DBG("-t %s -X %s", table_name, chain);
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        return iptables_delete_chain(table, chain);
@@ -2138,7 +2147,7 @@ int __connman_iptables_flush_chain(const char *table_name,
        DBG("-t %s -F %s", table_name, chain);
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        return iptables_flush_chain(table, chain);
@@ -2153,7 +2162,7 @@ int __connman_iptables_change_policy(const char *table_name,
        DBG("-t %s -F %s", table_name, chain);
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        return iptables_change_policy(table, chain, policy);
@@ -2169,7 +2178,7 @@ int __connman_iptables_append(const char *table_name,
        int err;
 
        ctx = g_try_new0(struct parse_context, 1);
-       if (ctx == NULL)
+       if (!ctx)
                return -ENOMEM;
 
        DBG("-t %s -A %s %s", table_name, chain, rule_spec);
@@ -2179,7 +2188,7 @@ int __connman_iptables_append(const char *table_name,
                goto out;
 
        table = get_table(table_name);
-       if (table == NULL) {
+       if (!table) {
                err = -EINVAL;
                goto out;
        }
@@ -2188,7 +2197,7 @@ int __connman_iptables_append(const char *table_name,
        if (err < 0)
                goto out;
 
-       if (ctx->xt_t == NULL)
+       if (!ctx->xt_t)
                target_name = NULL;
        else
                target_name = ctx->xt_t->name;
@@ -2212,7 +2221,7 @@ int __connman_iptables_insert(const char *table_name,
        int err;
 
        ctx = g_try_new0(struct parse_context, 1);
-       if (ctx == NULL)
+       if (!ctx)
                return -ENOMEM;
 
        DBG("-t %s -I %s %s", table_name, chain, rule_spec);
@@ -2222,7 +2231,7 @@ int __connman_iptables_insert(const char *table_name,
                goto out;
 
        table = get_table(table_name);
-       if (table == NULL) {
+       if (!table) {
                err = -EINVAL;
                goto out;
        }
@@ -2231,7 +2240,7 @@ int __connman_iptables_insert(const char *table_name,
        if (err < 0)
                goto out;
 
-       if (ctx->xt_t == NULL)
+       if (!ctx->xt_t)
                target_name = NULL;
        else
                target_name = ctx->xt_t->name;
@@ -2255,7 +2264,7 @@ int __connman_iptables_delete(const char *table_name,
        int err;
 
        ctx = g_try_new0(struct parse_context, 1);
-       if (ctx == NULL)
+       if (!ctx)
                return -ENOMEM;
 
        DBG("-t %s -D %s %s", table_name, chain, rule_spec);
@@ -2265,7 +2274,7 @@ int __connman_iptables_delete(const char *table_name,
                goto out;
 
        table = get_table(table_name);
-       if (table == NULL) {
+       if (!table) {
                err = -EINVAL;
                goto out;
        }
@@ -2274,7 +2283,7 @@ int __connman_iptables_delete(const char *table_name,
        if (err < 0)
                goto out;
 
-       if (ctx->xt_t == NULL)
+       if (!ctx->xt_t)
                target_name = NULL;
        else
                target_name = ctx->xt_t->name;
@@ -2298,12 +2307,12 @@ int __connman_iptables_commit(const char *table_name)
        DBG("%s", table_name);
 
        table = g_hash_table_lookup(table_hash, table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        repl = iptables_blob(table);
 
-       if (debug_enabled == TRUE)
+       if (debug_enabled)
                dump_ipt_replace(repl);
 
        err = iptables_replace(table, repl);
@@ -2312,7 +2321,7 @@ int __connman_iptables_commit(const char *table_name)
        g_free(repl);
 
        if (err < 0)
-           return err;
+               return err;
 
        g_hash_table_remove(table_hash, table_name);
 
@@ -2340,7 +2349,7 @@ static int iterate_chains_cb(struct ipt_entry *entry, int builtin,
        target = ipt_get_target(entry);
 
        if (!g_strcmp0(target->u.user.name, IPT_ERROR_TARGET))
-               (*cb)((const char*)target->data, cbd->user_data);
+               (*cb)((const char *)target->data, cbd->user_data);
        else if (builtin >= 0)
                (*cb)(hooknames[builtin], cbd->user_data);
 
@@ -2355,7 +2364,7 @@ int __connman_iptables_iterate_chains(const char *table_name,
        struct connman_iptables *table;
 
        table = get_table(table_name);
-       if (table == NULL)
+       if (!table)
                return -EINVAL;
 
        iterate_entries(table->blob_entries->entrytable,
@@ -2375,7 +2384,7 @@ int __connman_iptables_init(void)
        DBG("");
 
        if (getenv("CONNMAN_IPTABLES_DEBUG"))
-               debug_enabled = TRUE;
+               debug_enabled = true;
 
        table_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
                                                NULL, remove_table);