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Message-ID: <4B4D1372.9060702@gmail.com>
Date: Wed, 13 Jan 2010 01:27:30 +0100
From: Daniel Borkmann <danborkmann@...glemail.com>
To: Matt Mackall <mpm@...enic.com>
CC: David Miller <davem@...emloft.net>, danborkmann@...glemail.com,
linux-kernel@...r.kernel.org, jmoyer@...hat.com,
netdev@...r.kernel.org, netdev@....sgi.com
Subject: Re: [PATCH] netpoll: allow execution of multiple rx_hooks per interface
Daniel Borkmann wrote:
> Matt Mackall wrote:
>> On Mon, 2010-01-11 at 15:59 -0800, David Miller wrote:
>>> From: Matt Mackall <mpm@...enic.com>
>>> Date: Mon, 11 Jan 2010 17:21:48 -0600
>>>
>>>> Looks pretty good. Dave?
>>>>
>>>> Acked-by: Matt Mackall <mpm@...enic.com>
>>> I don't like the loop for RX ARP processing.
>>>
>>> The packet contents aren't going to change, so doing basic
>>> packet validation inside of the "for each RX client" loop
>>> of arp_reply() doesn't make any sense.
>> True. Dan, please help our poor compilers with some manual loop
>> invariant motion.
>
> Okay, true. I'll fix this by tomorrow and resend the patch.
Here the fix of the RX ARP processing routine. Content that isn't
going to change is out-of-loop.
Successfully tested on my machines.
Signed-off-by: Daniel Borkmann <danborkmann@...glemail.com>
diff -Nur a/include/linux/netpoll.h b/include/linux/netpoll.h
--- a/include/linux/netpoll.h 2010-01-05 23:52:58.000000000 +0100
+++ b/include/linux/netpoll.h 2010-01-07 23:19:25.000000000 +0100
@@ -21,15 +21,20 @@
__be32 local_ip, remote_ip;
u16 local_port, remote_port;
u8 remote_mac[ETH_ALEN];
+
+ struct list_head rx; /* rx_np list element */
};
struct netpoll_info {
atomic_t refcnt;
+
int rx_flags;
spinlock_t rx_lock;
- struct netpoll *rx_np; /* netpoll that registered an rx_hook */
+ struct list_head rx_np; /* netpolls that registered an rx_hook */
+
struct sk_buff_head arp_tx; /* list of arp requests to reply to */
struct sk_buff_head txq;
+
struct delayed_work tx_work;
};
@@ -51,7 +56,7 @@
unsigned long flags;
int ret = 0;
- if (!npinfo || (!npinfo->rx_np && !npinfo->rx_flags))
+ if (!npinfo || (list_empty(&npinfo->rx_np) && !npinfo->rx_flags))
return 0;
spin_lock_irqsave(&npinfo->rx_lock, flags);
@@ -67,7 +72,7 @@
{
struct netpoll_info *npinfo = skb->dev->npinfo;
- return npinfo && (npinfo->rx_np || npinfo->rx_flags);
+ return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
}
static inline int netpoll_receive_skb(struct sk_buff *skb)
diff -Nur a/net/core/netpoll.c b/net/core/netpoll.c
--- a/net/core/netpoll.c 2010-01-05 23:53:07.000000000 +0100
+++ b/net/core/netpoll.c 2010-01-12 23:36:48.000000000 +0100
@@ -407,11 +407,24 @@
__be32 sip, tip;
unsigned char *sha;
struct sk_buff *send_skb;
- struct netpoll *np = NULL;
+ struct netpoll *np, *tmp;
+ unsigned long flags;
+ int hits = 0;
+
+ if (list_empty(&npinfo->rx_np))
+ return;
+
+ /* Before checking the packet, we do some early
+ inspection whether this is interesting at all */
+ spin_lock_irqsave(&npinfo->rx_lock, flags);
+ list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
+ if (np->dev == skb->dev)
+ hits++;
+ }
+ spin_unlock_irqrestore(&npinfo->rx_lock, flags);
- if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
- np = npinfo->rx_np;
- if (!np)
+ /* No netpoll struct is using this dev */
+ if (!hits)
return;
/* No arp on this interface */
@@ -437,77 +450,91 @@
arp_ptr += skb->dev->addr_len;
memcpy(&sip, arp_ptr, 4);
arp_ptr += 4;
- /* if we actually cared about dst hw addr, it would get copied here */
+ /* If we actually cared about dst hw addr,
+ it would get copied here */
arp_ptr += skb->dev->addr_len;
memcpy(&tip, arp_ptr, 4);
/* Should we ignore arp? */
- if (tip != np->local_ip ||
- ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
+ if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
return;
size = arp_hdr_len(skb->dev);
- send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
- LL_RESERVED_SPACE(np->dev));
-
- if (!send_skb)
- return;
-
- skb_reset_network_header(send_skb);
- arp = (struct arphdr *) skb_put(send_skb, size);
- send_skb->dev = skb->dev;
- send_skb->protocol = htons(ETH_P_ARP);
-
- /* Fill the device header for the ARP frame */
- if (dev_hard_header(send_skb, skb->dev, ptype,
- sha, np->dev->dev_addr,
- send_skb->len) < 0) {
- kfree_skb(send_skb);
- return;
- }
- /*
- * Fill out the arp protocol part.
- *
- * we only support ethernet device type,
- * which (according to RFC 1390) should always equal 1 (Ethernet).
- */
+ spin_lock_irqsave(&npinfo->rx_lock, flags);
+ list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
+ if (tip != np->local_ip)
+ continue;
+
+ send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
+ LL_RESERVED_SPACE(np->dev));
+ if (!send_skb)
+ continue;
+
+ skb_reset_network_header(send_skb);
+ arp = (struct arphdr *) skb_put(send_skb, size);
+ send_skb->dev = skb->dev;
+ send_skb->protocol = htons(ETH_P_ARP);
+
+ /* Fill the device header for the ARP frame */
+ if (dev_hard_header(send_skb, skb->dev, ptype,
+ sha, np->dev->dev_addr,
+ send_skb->len) < 0) {
+ kfree_skb(send_skb);
+ continue;
+ }
- arp->ar_hrd = htons(np->dev->type);
- arp->ar_pro = htons(ETH_P_IP);
- arp->ar_hln = np->dev->addr_len;
- arp->ar_pln = 4;
- arp->ar_op = htons(type);
-
- arp_ptr=(unsigned char *)(arp + 1);
- memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
- arp_ptr += np->dev->addr_len;
- memcpy(arp_ptr, &tip, 4);
- arp_ptr += 4;
- memcpy(arp_ptr, sha, np->dev->addr_len);
- arp_ptr += np->dev->addr_len;
- memcpy(arp_ptr, &sip, 4);
+ /*
+ * Fill out the arp protocol part.
+ *
+ * we only support ethernet device type,
+ * which (according to RFC 1390) should
+ * always equal 1 (Ethernet).
+ */
- netpoll_send_skb(np, send_skb);
+ arp->ar_hrd = htons(np->dev->type);
+ arp->ar_pro = htons(ETH_P_IP);
+ arp->ar_hln = np->dev->addr_len;
+ arp->ar_pln = 4;
+ arp->ar_op = htons(type);
+
+ arp_ptr = (unsigned char *)(arp + 1);
+ memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
+ arp_ptr += np->dev->addr_len;
+ memcpy(arp_ptr, &tip, 4);
+ arp_ptr += 4;
+ memcpy(arp_ptr, sha, np->dev->addr_len);
+ arp_ptr += np->dev->addr_len;
+ memcpy(arp_ptr, &sip, 4);
+
+ netpoll_send_skb(np, send_skb);
+
+ /* If there are several rx_hooks for the same address,
+ we're fine by sending a single reply */
+ break;
+ }
+ spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
int __netpoll_rx(struct sk_buff *skb)
{
int proto, len, ulen;
+ int hits = 0;
struct iphdr *iph;
struct udphdr *uh;
- struct netpoll_info *npi = skb->dev->npinfo;
- struct netpoll *np = npi->rx_np;
+ struct netpoll_info *npinfo = skb->dev->npinfo;
+ struct netpoll *np, *tmp;
- if (!np)
+ if (list_empty(&npinfo->rx_np))
goto out;
+
if (skb->dev->type != ARPHRD_ETHER)
goto out;
/* check if netpoll clients need ARP */
if (skb->protocol == htons(ETH_P_ARP) &&
atomic_read(&trapped)) {
- skb_queue_tail(&npi->arp_tx, skb);
+ skb_queue_tail(&npinfo->arp_tx, skb);
return 1;
}
@@ -551,16 +578,23 @@
goto out;
if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
goto out;
- if (np->local_ip && np->local_ip != iph->daddr)
- goto out;
- if (np->remote_ip && np->remote_ip != iph->saddr)
- goto out;
- if (np->local_port && np->local_port != ntohs(uh->dest))
- goto out;
- np->rx_hook(np, ntohs(uh->source),
- (char *)(uh+1),
- ulen - sizeof(struct udphdr));
+ list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
+ if (np->local_ip && np->local_ip != iph->daddr)
+ continue;
+ if (np->remote_ip && np->remote_ip != iph->saddr)
+ continue;
+ if (np->local_port && np->local_port != ntohs(uh->dest))
+ continue;
+
+ np->rx_hook(np, ntohs(uh->source),
+ (char *)(uh+1),
+ ulen - sizeof(struct udphdr));
+ hits++;
+ }
+
+ if (!hits)
+ goto out;
kfree_skb(skb);
return 1;
@@ -684,6 +718,7 @@
struct net_device *ndev = NULL;
struct in_device *in_dev;
struct netpoll_info *npinfo;
+ struct netpoll *npe, *tmp;
unsigned long flags;
int err;
@@ -704,7 +739,7 @@
}
npinfo->rx_flags = 0;
- npinfo->rx_np = NULL;
+ INIT_LIST_HEAD(&npinfo->rx_np);
spin_lock_init(&npinfo->rx_lock);
skb_queue_head_init(&npinfo->arp_tx);
@@ -785,7 +820,7 @@
if (np->rx_hook) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_flags |= NETPOLL_RX_ENABLED;
- npinfo->rx_np = np;
+ list_add_tail(&np->rx, &npinfo->rx_np);
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
@@ -801,9 +836,16 @@
return 0;
release:
- if (!ndev->npinfo)
+ if (!ndev->npinfo) {
+ spin_lock_irqsave(&npinfo->rx_lock, flags);
+ list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
+ npe->dev = NULL;
+ }
+ spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+
kfree(npinfo);
- np->dev = NULL;
+ }
+
dev_put(ndev);
return err;
}
@@ -823,10 +865,11 @@
if (np->dev) {
npinfo = np->dev->npinfo;
if (npinfo) {
- if (npinfo->rx_np == np) {
+ if (!list_empty(&npinfo->rx_np)) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
- npinfo->rx_np = NULL;
- npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
+ list_del(&np->rx);
+ if (list_empty(&npinfo->rx_np))
+ npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
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