There is nothing wrong with the current code.
However, skb_gso_segment is expensive, so it would be nice
if we could avoid it in the future.
Since userspace must be prepared to receive larger-than-mtu-packets
(which will also have incorrect l3/l4 checksums), we cannot simply
remove it.
The plan is to add a per-queue feature flag that userspace can
set when binding the queue.
The problem is that in nf_queue, we only have a queue number,
not the queue context/configuration settings.
This patch should have no impact other than the skb_gso_segment
call now being in a function that has access to the queue config data.
The size new size attribute in nf_queue_entry is needed so
nfnetlink_queue can duplicate the entry of the gso skb
when segmenting the skb while also copying the route key.
Next step: avoid skb_gso_segment when queue config says so.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
Change since V2:
- don't mess up entry->skb assignment when duplicating
nf_queue_entry to avoid OOPS with CONFIG_BRIDGE_NETFILTER=y
include/net/netfilter/nf_queue.h | 6 ++
net/netfilter/nf_queue.c | 96 ++-------------------
net/netfilter/nfnetlink_queue_core.c | 154 ++++++++++++++++++++++++++++++----
3 files changed, 152 insertions(+), 104 deletions(-)
diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h
index fb1c0be..aaba4bb 100644
--- a/include/net/netfilter/nf_queue.h
+++ b/include/net/netfilter/nf_queue.h
@@ -9,10 +9,13 @@ struct nf_queue_entry {
struct nf_hook_ops *elem;
u_int8_t pf;
+ u16 size; /* sizeof(entry) + saved route keys */
unsigned int hook;
struct net_device *indev;
struct net_device *outdev;
int (*okfn)(struct sk_buff *);
+
+ /* extra space to store route keys */
};
#define nf_queue_entry_reroute(x) ((void *)x + sizeof(struct nf_queue_entry))
@@ -27,4 +30,7 @@ void nf_register_queue_handler(const struct nf_queue_handler *qh);
void nf_unregister_queue_handler(void);
extern void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry);
+void nf_queue_entry_release_refs(struct nf_queue_entry *entry);
+
#endif /* _NF_QUEUE_H */
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 1d91e77..5d24b1f 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -45,7 +45,7 @@ void nf_unregister_queue_handler(void)
}
EXPORT_SYMBOL(nf_unregister_queue_handler);
-static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
+void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
{
/* Release those devices we held, or Alexey will kill me. */
if (entry->indev)
@@ -65,9 +65,10 @@ static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
/* Drop reference to owner of hook which queued us. */
module_put(entry->elem->owner);
}
+EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
/* Bump dev refs so they don't vanish while packet is out */
-static bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
{
if (!try_module_get(entry->elem->owner))
return false;
@@ -92,12 +93,13 @@ static bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
return true;
}
+EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
/*
* Any packet that leaves via this function must come back
* through nf_reinject().
*/
-static int __nf_queue(struct sk_buff *skb,
+int nf_queue(struct sk_buff *skb,
struct nf_hook_ops *elem,
u_int8_t pf, unsigned int hook,
struct net_device *indev,
@@ -137,6 +139,7 @@ static int __nf_queue(struct sk_buff *skb,
.indev = indev,
.outdev = outdev,
.okfn = okfn,
+ .size = sizeof(*entry) + afinfo->route_key_size,
};
if (!nf_queue_entry_get_refs(entry)) {
@@ -163,87 +166,6 @@ err:
return status;
}
-#ifdef CONFIG_BRIDGE_NETFILTER
-/* When called from bridge netfilter, skb->data must point to MAC header
- * before calling skb_gso_segment(). Else, original MAC header is lost
- * and segmented skbs will be sent to wrong destination.
- */
-static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
-{
- if (skb->nf_bridge)
- __skb_push(skb, skb->network_header - skb->mac_header);
-}
-
-static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
-{
- if (skb->nf_bridge)
- __skb_pull(skb, skb->network_header - skb->mac_header);
-}
-#else
-#define nf_bridge_adjust_skb_data(s) do {} while (0)
-#define nf_bridge_adjust_segmented_data(s) do {} while (0)
-#endif
-
-int nf_queue(struct sk_buff *skb,
- struct nf_hook_ops *elem,
- u_int8_t pf, unsigned int hook,
- struct net_device *indev,
- struct net_device *outdev,
- int (*okfn)(struct sk_buff *),
- unsigned int queuenum)
-{
- struct sk_buff *segs;
- int err = -EINVAL;
- unsigned int queued;
-
- if (!skb_is_gso(skb))
- return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
- queuenum);
-
- switch (pf) {
- case NFPROTO_IPV4:
- skb->protocol = htons(ETH_P_IP);
- break;
- case NFPROTO_IPV6:
- skb->protocol = htons(ETH_P_IPV6);
- break;
- }
-
- nf_bridge_adjust_skb_data(skb);
- segs = skb_gso_segment(skb, 0);
- /* 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))
- goto out_err;
- queued = 0;
- err = 0;
- do {
- struct sk_buff *nskb = segs->next;
-
- segs->next = NULL;
- if (err == 0) {
- nf_bridge_adjust_segmented_data(segs);
- err = __nf_queue(segs, elem, pf, hook, indev,
- outdev, okfn, queuenum);
- }
- if (err == 0)
- queued++;
- else
- kfree_skb(segs);
- segs = nskb;
- } while (segs);
-
- if (queued) {
- kfree_skb(skb);
- return 0;
- }
- out_err:
- nf_bridge_adjust_segmented_data(skb);
- return err;
-}
-
void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
{
struct sk_buff *skb = entry->skb;
@@ -283,9 +205,9 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
local_bh_enable();
break;
case NF_QUEUE:
- err = __nf_queue(skb, elem, entry->pf, entry->hook,
- entry->indev, entry->outdev, entry->okfn,
- verdict >> NF_VERDICT_QBITS);
+ err = nf_queue(skb, elem, entry->pf, entry->hook,
+ entry->indev, entry->outdev, entry->okfn,
+ verdict >> NF_VERDICT_QBITS);
if (err < 0) {
if (err == -ECANCELED)
goto next_hook;
diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index 94e2e4f..38c8a7a 100644
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -479,28 +479,13 @@ nla_put_failure:
}
static int
-nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
+__nfqnl_enqueue_packet(struct net *net, struct nfqnl_instance *queue,
+ struct nf_queue_entry *entry)
{
struct sk_buff *nskb;
- struct nfqnl_instance *queue;
int err = -ENOBUFS;
__be32 *packet_id_ptr;
int failopen = 0;
- struct net *net = dev_net(entry->indev ?
- entry->indev : entry->outdev);
- struct nfnl_queue_net *q = nfnl_queue_pernet(net);
-
- /* rcu_read_lock()ed by nf_hook_slow() */
- queue = instance_lookup(q, queuenum);
- if (!queue) {
- err = -ESRCH;
- goto err_out;
- }
-
- if (queue->copy_mode == NFQNL_COPY_NONE) {
- err = -EINVAL;
- goto err_out;
- }
nskb = nfqnl_build_packet_message(queue, entry, &packet_id_ptr);
if (nskb == NULL) {
@@ -545,6 +530,141 @@ err_out:
return err;
}
+static struct nf_queue_entry *
+nf_queue_entry_dup(struct nf_queue_entry *e)
+{
+ struct nf_queue_entry *entry = kmemdup(e, e->size, GFP_ATOMIC);
+ if (entry) {
+ if (nf_queue_entry_get_refs(entry))
+ return entry;
+ kfree(entry);
+ }
+ return NULL;
+}
+
+#ifdef CONFIG_BRIDGE_NETFILTER
+/* When called from bridge netfilter, skb->data must point to MAC header
+ * before calling skb_gso_segment(). Else, original MAC header is lost
+ * and segmented skbs will be sent to wrong destination.
+ */
+static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
+{
+ if (skb->nf_bridge)
+ __skb_push(skb, skb->network_header - skb->mac_header);
+}
+
+static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
+{
+ if (skb->nf_bridge)
+ __skb_pull(skb, skb->network_header - skb->mac_header);
+}
+#else
+#define nf_bridge_adjust_skb_data(s) do {} while (0)
+#define nf_bridge_adjust_segmented_data(s) do {} while (0)
+#endif
+
+static void free_entry(struct nf_queue_entry *entry)
+{
+ nf_queue_entry_release_refs(entry);
+ kfree(entry);
+}
+
+static int
+__nfqnl_enqueue_packet_gso(struct net *net, struct nfqnl_instance *queue,
+ struct sk_buff *skb, struct nf_queue_entry *entry)
+{
+ int ret = -ENOMEM;
+ struct nf_queue_entry *entry_seg;
+
+ nf_bridge_adjust_segmented_data(skb);
+
+ if (skb->next == NULL) { /* last packet, no need to copy entry */
+ struct sk_buff *gso_skb = entry->skb;
+ entry->skb = skb;
+ ret = __nfqnl_enqueue_packet(net, queue, entry);
+ if (ret)
+ entry->skb = gso_skb;
+ return ret;
+ }
+
+ skb->next = NULL;
+
+ entry_seg = nf_queue_entry_dup(entry);
+ if (entry_seg) {
+ entry_seg->skb = skb;
+ ret = __nfqnl_enqueue_packet(net, queue, entry_seg);
+ if (ret)
+ free_entry(entry_seg);
+ }
+ return ret;
+}
+
+static int
+nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
+{
+ unsigned int queued;
+ struct nfqnl_instance *queue;
+ struct sk_buff *skb, *segs;
+ int err = -ENOBUFS;
+ struct net *net = dev_net(entry->indev ?
+ entry->indev : entry->outdev);
+ struct nfnl_queue_net *q = nfnl_queue_pernet(net);
+
+ /* rcu_read_lock()ed by nf_hook_slow() */
+ queue = instance_lookup(q, queuenum);
+ if (!queue)
+ return -ESRCH;
+
+ if (queue->copy_mode == NFQNL_COPY_NONE)
+ return -EINVAL;
+
+ if (!skb_is_gso(entry->skb))
+ return __nfqnl_enqueue_packet(net, queue, entry);
+
+ skb = entry->skb;
+
+ switch (entry->pf) {
+ case NFPROTO_IPV4:
+ skb->protocol = htons(ETH_P_IP);
+ break;
+ case NFPROTO_IPV6:
+ skb->protocol = htons(ETH_P_IPV6);
+ break;
+ }
+
+ nf_bridge_adjust_skb_data(skb);
+ segs = skb_gso_segment(skb, 0);
+ /* 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))
+ goto out_err;
+ queued = 0;
+ err = 0;
+ do {
+ struct sk_buff *nskb = segs->next;
+ if (err == 0)
+ err = __nfqnl_enqueue_packet_gso(net, queue,
+ segs, entry);
+ if (err == 0)
+ queued++;
+ else
+ kfree_skb(segs);
+ segs = nskb;
+ } while (segs);
+
+ if (queued) {
+ if (err) /* some segments are already queued */
+ free_entry(entry);
+ kfree_skb(skb);
+ return 0;
+ }
+ out_err:
+ nf_bridge_adjust_segmented_data(skb);
+ return err;
+}
+
static int
nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff)
{
--
1.7.8.6
--
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