Daniel Borkmann wrote: > Matt Mackall wrote: >> On Mon, 2010-01-11 at 15:59 -0800, David Miller wrote: >>> From: Matt Mackall >>> Date: Mon, 11 Jan 2010 17:21:48 -0600 >>> >>>> Looks pretty good. Dave? >>>> >>>> Acked-by: Matt Mackall >>> 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 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); }