Re: [PATCH] IPv6 : add multicast routing verify which net_device is lo
From: Wang Xingtong <hidden>
Date: 2011-12-20 09:48:37
Wang Xingtong 写道:
In currently routing subsystem, when we lookup a multicast routing to send muticast packets to outside, rt6_device_match will return the rt6_info which it's match first. if we add a multicast route on loopback devices beforce the others interface, rt6_device_match will retrun the rt6_info which rt6i_dev->name is "lo". But, obviously, we can't send a muticast packet to outside using loopback devices. It case all multicast packets blocking. Commit 4af04aba93f47699e disabled kernel add multicast route on lo automatically. However, we can't surmise the routing-add order or interdict add multicast routing on loopback devices in user space. The bug still exist. So, i think more stronger routing subsystem is necessary.
sorry, the patch has some problem , i will send V2 later.
quoted hunk ↗ jump to hunk
Signed-off-by: Wang xingtong <redacted> --- net/ipv6/route.c | 19 ++++++++++++++++--- 1 files changed, 16 insertions(+), 3 deletions(-)diff --git a/net/ipv6/route.c b/net/ipv6/route.c index b582a0a..3871ef4 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c@@ -334,9 +334,16 @@ static inline struct rt6_info*rt6_device_match(struct net *net, struct rt6_info *local = NULL; struct rt6_info *sprt; - if (!oif && ipv6_addr_any(saddr)) + if (!oif && ipv6_addr_any(saddr)){ + if (unlikely(rt->rt6i_dev->flags & IFF_LOOPBACK && + ipv6_addr_is_multicast(&rt->rt6i_dst.addr))){ + rt=rt->dst.rt6_next; + goto match; + } goto out; + } +match: for (sprt = rt; sprt; sprt = sprt->dst.rt6_next) { struct net_device *dev = sprt->rt6i_dev;@@ -355,9 +362,15 @@ static inline struct rt6_info*rt6_device_match(struct net *net, local = sprt; } } else { - if (ipv6_chk_addr(net, saddr, dev, - flags & RT6_LOOKUP_F_IFACE)) + if (ipv6_addr_any(saddr)){ + if (unlikely(rt->rt6i_dev->flags & IFF_LOOPBACK && + ipv6_addr_is_multicast(&rt->rt6i_dst.addr))){ + continue; return sprt; + } + else if (ipv6_chk_addr(net, saddr, dev, + flags & RT6_LOOKUP_F_IFACE)) + return sprt; } }