netpoll: allow execution of multiple rx_hooks per interface

Signed-off-by: Daniel Borkmann <danborkmann@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 106 insertions, 63 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 0b4d0d35ef40..7aa697253765 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -407,11 +407,24 @@ static void arp_reply(struct sk_buff *skb)
         __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 @@ static void arp_reply(struct sk_buff *skb)
         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);
+        spin_lock_irqsave(&npinfo->rx_lock, flags);
+        list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
+                if (tip != np->local_ip)
+                        continue;
 
-        /* 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;
-        }
+                send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
+                                    LL_RESERVED_SPACE(np->dev));
+                if (!send_skb)
+                        continue;
 
-        /*
-         * Fill out the arp protocol part.
-         *
-         * we only support ethernet device type,
-         * which (according to RFC 1390) should always equal 1 (Ethernet).
-         */
+                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);
 
-        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);
+                /* 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_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 @@ int __netpoll_rx(struct sk_buff *skb)
                 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 @@ int netpoll_setup(struct netpoll *np)
         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 @@ int netpoll_setup(struct netpoll *np)
                 }
 
                 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 @@ int netpoll_setup(struct netpoll *np)
         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 @@ int netpoll_setup(struct netpoll *np)
         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 @@ void netpoll_cleanup(struct netpoll *np)
         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);
                         }