netfilter: make proc/net/ip* print names from foreign NFPROTO

When extensions were moved to the NFPROTO_UNSPEC wildcard in
ab4f21e6fb1c09b13c4c3cb8357babe8223471bd, they disappeared from the
procfs files.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 142 insertions, 57 deletions

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index bfbf521f6ea5..5baccfa5a0de 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -827,59 +827,143 @@ static const struct file_operations xt_table_ops = {
         .release = seq_release_net,
 };
 
-static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
+/*
+ * Traverse state for ip{,6}_{tables,matches} for helping crossing
+ * the multi-AF mutexes.
+ */
+struct nf_mttg_trav {
+        struct list_head *head, *curr;
+        uint8_t class, nfproto;
+};
+
+enum {
+        MTTG_TRAV_INIT,
+        MTTG_TRAV_NFP_UNSPEC,
+        MTTG_TRAV_NFP_SPEC,
+        MTTG_TRAV_DONE,
+};
+
+static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
+    bool is_target)
 {
-        struct proc_dir_entry *pde = (struct proc_dir_entry *)seq->private;
-        u_int16_t af = (unsigned long)pde->data;
+        static const uint8_t next_class[] = {
+                [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
+                [MTTG_TRAV_NFP_SPEC]   = MTTG_TRAV_DONE,
+        };
+        struct nf_mttg_trav *trav = seq->private;
+
+        switch (trav->class) {
+        case MTTG_TRAV_INIT:
+                trav->class = MTTG_TRAV_NFP_UNSPEC;
+                mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
+                trav->head = trav->curr = is_target ?
+                        &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
+                break;
+        case MTTG_TRAV_NFP_UNSPEC:
+                trav->curr = trav->curr->next;
+                if (trav->curr != trav->head)
+                        break;
+                mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
+                mutex_lock(&xt[trav->nfproto].mutex);
+                trav->head = trav->curr = is_target ?
+                        &xt[trav->nfproto].target : &xt[trav->nfproto].match;
+                trav->class = next_class[trav->class];
+                break;
+        case MTTG_TRAV_NFP_SPEC:
+                trav->curr = trav->curr->next;
+                if (trav->curr != trav->head)
+                        break;
+                /* fallthru, _stop will unlock */
+        default:
+                return NULL;
+        }
 
-        mutex_lock(&xt[af].mutex);
-        return seq_list_start(&xt[af].match, *pos);
+        if (ppos != NULL)
+                ++*ppos;
+        return trav;
 }
 
-static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
+    bool is_target)
 {
-        struct proc_dir_entry *pde = (struct proc_dir_entry *)seq->private;
-        u_int16_t af = (unsigned long)pde->data;
+        struct nf_mttg_trav *trav = seq->private;
+        unsigned int j;
 
-        return seq_list_next(v, &xt[af].match, pos);
+        trav->class = MTTG_TRAV_INIT;
+        for (j = 0; j < *pos; ++j)
+                if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
+                        return NULL;
+        return trav;
 }
 
-static void xt_match_seq_stop(struct seq_file *seq, void *v)
+static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
 {
-        struct proc_dir_entry *pde = seq->private;
-        u_int16_t af = (unsigned long)pde->data;
+        struct nf_mttg_trav *trav = seq->private;
+
+        switch (trav->class) {
+        case MTTG_TRAV_NFP_UNSPEC:
+                mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
+                break;
+        case MTTG_TRAV_NFP_SPEC:
+                mutex_unlock(&xt[trav->nfproto].mutex);
+                break;
+        }
+}
 
-        mutex_unlock(&xt[af].mutex);
+static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
+{
+        return xt_mttg_seq_start(seq, pos, false);
 }
 
-static int xt_match_seq_show(struct seq_file *seq, void *v)
+static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
 {
-        struct xt_match *match = list_entry(v, struct xt_match, list);
+        return xt_mttg_seq_next(seq, v, ppos, false);
+}
 
-        if (strlen(match->name))
-                return seq_printf(seq, "%s\n", match->name);
-        else
-                return 0;
+static int xt_match_seq_show(struct seq_file *seq, void *v)
+{
+        const struct nf_mttg_trav *trav = seq->private;
+        const struct xt_match *match;
+
+        switch (trav->class) {
+        case MTTG_TRAV_NFP_UNSPEC:
+        case MTTG_TRAV_NFP_SPEC:
+                if (trav->curr == trav->head)
+                        return 0;
+                match = list_entry(trav->curr, struct xt_match, list);
+                return (*match->name == '\0') ? 0 :
+                       seq_printf(seq, "%s\n", match->name);
+        }
+        return 0;
 }
 
 static const struct seq_operations xt_match_seq_ops = {
         .start  = xt_match_seq_start,
         .next   = xt_match_seq_next,
-        .stop   = xt_match_seq_stop,
+        .stop   = xt_mttg_seq_stop,
         .show   = xt_match_seq_show,
 };
 
 static int xt_match_open(struct inode *inode, struct file *file)
 {
+        struct seq_file *seq;
+        struct nf_mttg_trav *trav;
         int ret;
 
-        ret = seq_open(file, &xt_match_seq_ops);
-        if (!ret) {
-                struct seq_file *seq = file->private_data;
+        trav = kmalloc(sizeof(*trav), GFP_KERNEL);
+        if (trav == NULL)
+                return -ENOMEM;
 
-                seq->private = PDE(inode);
+        ret = seq_open(file, &xt_match_seq_ops);
+        if (ret < 0) {
+                kfree(trav);
+                return ret;
         }
-        return ret;
+
+        seq = file->private_data;
+        seq->private = trav;
+        trav->nfproto = (unsigned long)PDE(inode)->data;
+        return 0;
 }
 
 static const struct file_operations xt_match_ops = {
@@ -887,62 +971,63 @@ static const struct file_operations xt_match_ops = {
         .open    = xt_match_open,
         .read    = seq_read,
         .llseek  = seq_lseek,
-        .release = seq_release,
+        .release = seq_release_private,
 };
 
 static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
 {
-        struct proc_dir_entry *pde = (struct proc_dir_entry *)seq->private;
-        u_int16_t af = (unsigned long)pde->data;
-
-        mutex_lock(&xt[af].mutex);
-        return seq_list_start(&xt[af].target, *pos);
+        return xt_mttg_seq_start(seq, pos, true);
 }
 
-static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
 {
-        struct proc_dir_entry *pde = (struct proc_dir_entry *)seq->private;
-        u_int16_t af = (unsigned long)pde->data;
-
-        return seq_list_next(v, &xt[af].target, pos);
-}
-
-static void xt_target_seq_stop(struct seq_file *seq, void *v)
-{
-        struct proc_dir_entry *pde = seq->private;
-        u_int16_t af = (unsigned long)pde->data;
-
-        mutex_unlock(&xt[af].mutex);
+        return xt_mttg_seq_next(seq, v, ppos, true);
 }
 
 static int xt_target_seq_show(struct seq_file *seq, void *v)
 {
-        struct xt_target *target = list_entry(v, struct xt_target, list);
-
-        if (strlen(target->name))
-                return seq_printf(seq, "%s\n", target->name);
-        else
-                return 0;
+        const struct nf_mttg_trav *trav = seq->private;
+        const struct xt_target *target;
+
+        switch (trav->class) {
+        case MTTG_TRAV_NFP_UNSPEC:
+        case MTTG_TRAV_NFP_SPEC:
+                if (trav->curr == trav->head)
+                        return 0;
+                target = list_entry(trav->curr, struct xt_target, list);
+                return (*target->name == '\0') ? 0 :
+                       seq_printf(seq, "%s\n", target->name);
+        }
+        return 0;
 }
 
 static const struct seq_operations xt_target_seq_ops = {
         .start  = xt_target_seq_start,
         .next   = xt_target_seq_next,
-        .stop   = xt_target_seq_stop,
+        .stop   = xt_mttg_seq_stop,
         .show   = xt_target_seq_show,
 };
 
 static int xt_target_open(struct inode *inode, struct file *file)
 {
+        struct seq_file *seq;
+        struct nf_mttg_trav *trav;
         int ret;
 
-        ret = seq_open(file, &xt_target_seq_ops);
-        if (!ret) {
-                struct seq_file *seq = file->private_data;
+        trav = kmalloc(sizeof(*trav), GFP_KERNEL);
+        if (trav == NULL)
+                return -ENOMEM;
 
-                seq->private = PDE(inode);
+        ret = seq_open(file, &xt_target_seq_ops);
+        if (ret < 0) {
+                kfree(trav);
+                return ret;
         }
-        return ret;
+
+        seq = file->private_data;
+        seq->private = trav;
+        trav->nfproto = (unsigned long)PDE(inode)->data;
+        return 0;
 }
 
 static const struct file_operations xt_target_ops = {
@@ -950,7 +1035,7 @@ static const struct file_operations xt_target_ops = {
         .open    = xt_target_open,
         .read    = seq_read,
         .llseek  = seq_lseek,
-        .release = seq_release,
+        .release = seq_release_private,
 };
 
 #define FORMAT_TABLES   "_tables_names"