From 545ecdc3b3a2fe0b54a3053bf8bf85321bbca7da Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Sat, 8 Jan 2011 13:57:12 +0000 Subject: [PATCH] arp: allow to invalidate specific ARP entries IPv4 over firewire needs to be able to remove ARP entries from the ARP cache that belong to nodes that are removed, because IPv4 over firewire uses ARP packets for private information about nodes. This information becomes invalid as soon as node drops off the bus and when it reconnects, its only possible to start talking to it after it responded to an ARP packet. But ARP cache prevents such packets from being sent. Signed-off-by: Maxim Levitsky Signed-off-by: David S. Miller --- include/net/arp.h | 1 + net/ipv4/arp.c | 29 ++++++++++++++++++----------- 2 files changed, 19 insertions(+), 11 deletions(-) diff --git a/include/net/arp.h b/include/net/arp.h index f4cf6ce6658..91f0568a04e 100644 --- a/include/net/arp.h +++ b/include/net/arp.h @@ -25,5 +25,6 @@ extern struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, const unsigned char *src_hw, const unsigned char *target_hw); extern void arp_xmit(struct sk_buff *skb); +int arp_invalidate(struct net_device *dev, __be32 ip); #endif /* _ARP_H */ diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index a2fc7b961db..04c8b69fd42 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1143,6 +1143,23 @@ static int arp_req_get(struct arpreq *r, struct net_device *dev) return err; } +int arp_invalidate(struct net_device *dev, __be32 ip) +{ + struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev); + int err = -ENXIO; + + if (neigh) { + if (neigh->nud_state & ~NUD_NOARP) + err = neigh_update(neigh, NULL, NUD_FAILED, + NEIGH_UPDATE_F_OVERRIDE| + NEIGH_UPDATE_F_ADMIN); + neigh_release(neigh); + } + + return err; +} +EXPORT_SYMBOL(arp_invalidate); + static int arp_req_delete_public(struct net *net, struct arpreq *r, struct net_device *dev) { @@ -1163,7 +1180,6 @@ static int arp_req_delete(struct net *net, struct arpreq *r, { int err; __be32 ip; - struct neighbour *neigh; if (r->arp_flags & ATF_PUBL) return arp_req_delete_public(net, r, dev); @@ -1181,16 +1197,7 @@ static int arp_req_delete(struct net *net, struct arpreq *r, if (!dev) return -EINVAL; } - err = -ENXIO; - neigh = neigh_lookup(&arp_tbl, &ip, dev); - if (neigh) { - if (neigh->nud_state & ~NUD_NOARP) - err = neigh_update(neigh, NULL, NUD_FAILED, - NEIGH_UPDATE_F_OVERRIDE| - NEIGH_UPDATE_F_ADMIN); - neigh_release(neigh); - } - return err; + return arp_invalidate(dev, ip); } /* -- 2.39.2