netfilter: nfnetlink_queue: return error number to caller

instead of returning -1 on error, return an error number to allow the
caller to handle some errors differently.

ECANCELED is used to indicate that the hook is going away and should be
ignored.

A followup patch will introduce more 'ignore this hook' conditions,
(depending on queue settings) and will move kfree_skb responsibility
to the caller.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index e69d537..91d66d2 100644 (file)
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -179,9 +179,11 @@ next_hook:
                if (ret == 0)
                        ret = -EPERM;
        } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
-               if (!nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
-                             verdict >> NF_VERDICT_BITS))
+               ret = nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
+                              verdict >> NF_VERDICT_BITS);
+               if (ret == -ECANCELED)
                        goto next_hook;
+               ret = 0;
        }
        rcu_read_unlock();
        return ret;

diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 1876f74..ad25c7e 100644 (file)
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -125,7 +125,7 @@ static int __nf_queue(struct sk_buff *skb,
                      int (*okfn)(struct sk_buff *),
                      unsigned int queuenum)
 {
-       int status;
+       int status = -ENOENT;
        struct nf_queue_entry *entry = NULL;
 #ifdef CONFIG_BRIDGE_NETFILTER
        struct net_device *physindev;
@@ -146,8 +146,10 @@ static int __nf_queue(struct sk_buff *skb,
                goto err_unlock;
 
        entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
-       if (!entry)
+       if (!entry) {
+               status = -ENOMEM;
                goto err_unlock;
+       }
 
        *entry = (struct nf_queue_entry) {
                .skb    = skb,
@@ -163,9 +165,8 @@ static int __nf_queue(struct sk_buff *skb,
        if (!try_module_get(entry->elem->owner)) {
                rcu_read_unlock();
                kfree(entry);
-               return 0;
+               return -ECANCELED;
        }
-
        /* Bump dev refs so they don't vanish while packet is out */
        if (indev)
                dev_hold(indev);
@@ -192,14 +193,14 @@ static int __nf_queue(struct sk_buff *skb,
                goto err;
        }
 
-       return 1;
+       return 0;
 
 err_unlock:
        rcu_read_unlock();
 err:
        kfree_skb(skb);
        kfree(entry);
-       return 1;
+       return status;
 }
 
 int nf_queue(struct sk_buff *skb,
@@ -211,6 +212,8 @@ int nf_queue(struct sk_buff *skb,
             unsigned int queuenum)
 {
        struct sk_buff *segs;
+       int err;
+       unsigned int queued;
 
        if (!skb_is_gso(skb))
                return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
@@ -227,19 +230,32 @@ int nf_queue(struct sk_buff *skb,
 
        segs = skb_gso_segment(skb, 0);
        kfree_skb(skb);
+       /* Does not use PTR_ERR to limit the number of error codes that can be
+        * returned by nf_queue.  For instance, callers rely on -ECANCELED to mean
+        * 'ignore this hook'.
+        */
        if (IS_ERR(segs))
-               return 1;
+               return -EINVAL;
 
+       queued = 0;
+       err = 0;
        do {
                struct sk_buff *nskb = segs->next;
 
                segs->next = NULL;
-               if (!__nf_queue(segs, elem, pf, hook, indev, outdev, okfn,
-                               queuenum))
+               if (err == 0)
+                       err = __nf_queue(segs, elem, pf, hook, indev,
+                                          outdev, okfn, queuenum);
+               if (err == 0)
+                       queued++;
+               else
                        kfree_skb(segs);
                segs = nskb;
        } while (segs);
-       return 1;
+
+       if (unlikely(err && queued))
+               err = 0;
+       return err;
 }
 
 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
@@ -247,6 +263,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
        struct sk_buff *skb = entry->skb;
        struct list_head *elem = &entry->elem->list;
        const struct nf_afinfo *afinfo;
+       int err;
 
        rcu_read_lock();
 
@@ -280,9 +297,10 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
                local_bh_enable();
                break;
        case NF_QUEUE:
-               if (!__nf_queue(skb, elem, entry->pf, entry->hook,
-                               entry->indev, entry->outdev, entry->okfn,
-                               verdict >> NF_VERDICT_BITS))
+               err = __nf_queue(skb, elem, entry->pf, entry->hook,
+                                entry->indev, entry->outdev, entry->okfn,
+                                verdict >> NF_VERDICT_BITS);
+               if (err == -ECANCELED)
                        goto next_hook;
                break;
        case NF_STOLEN:

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 68e67d1..b83123f 100644 (file)
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -387,25 +387,31 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
 {
        struct sk_buff *nskb;
        struct nfqnl_instance *queue;
-       int err;
+       int err = -ENOBUFS;
 
        /* rcu_read_lock()ed by nf_hook_slow() */
        queue = instance_lookup(queuenum);
-       if (!queue)
+       if (!queue) {
+               err = -ESRCH;
                goto err_out;
+       }
 
-       if (queue->copy_mode == NFQNL_COPY_NONE)
+       if (queue->copy_mode == NFQNL_COPY_NONE) {
+               err = -EINVAL;
                goto err_out;
+       }
 
        nskb = nfqnl_build_packet_message(queue, entry);
-       if (nskb == NULL)
+       if (nskb == NULL) {
+               err = -ENOMEM;
                goto err_out;
-
+       }
        spin_lock_bh(&queue->lock);
 
-       if (!queue->peer_pid)
+       if (!queue->peer_pid) {
+               err = -EINVAL;
                goto err_out_free_nskb;
-
+       }
        if (queue->queue_total >= queue->queue_maxlen) {
                queue->queue_dropped++;
                if (net_ratelimit())
@@ -432,7 +438,7 @@ err_out_free_nskb:
 err_out_unlock:
        spin_unlock_bh(&queue->lock);
 err_out:
-       return -1;
+       return err;
 }
 
 static int