From 1b70d792cf6775fb5d0737524387893daeb5374a Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 28 Aug 2017 13:53:34 -0700 Subject: [PATCH] ipv6: Use rt6i_idev index for echo replies to a local address Tariq repored local pings to linklocal address is failing: $ ifconfig ens8 ens8: flags=4163 mtu 1500 inet 11.141.16.6 netmask 255.255.0.0 broadcast 11.141.255.255 inet6 fe80::7efe:90ff:fecb:7502 prefixlen 64 scopeid 0x20 ether 7c:fe:90:cb:75:02 txqueuelen 1000 (Ethernet) RX packets 12 bytes 1164 (1.1 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 30 bytes 2484 (2.4 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 $ /bin/ping6 -c 3 fe80::7efe:90ff:fecb:7502%ens8 PING fe80::7efe:90ff:fecb:7502%ens8(fe80::7efe:90ff:fecb:7502) 56 data bytes Signed-off-by: David S. Miller --- include/net/ip6_route.h | 10 ++++++++++ net/ipv6/icmp.c | 33 ++++++++++++++++++++------------- 2 files changed, 30 insertions(+), 13 deletions(-) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 882bc3c7ccde..ee96f402cb75 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -164,6 +164,16 @@ void rt6_mtu_change(struct net_device *dev, unsigned int mtu); void rt6_remove_prefsrc(struct inet6_ifaddr *ifp); void rt6_clean_tohost(struct net *net, struct in6_addr *gateway); +static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb) +{ + const struct dst_entry *dst = skb_dst(skb); + const struct rt6_info *rt6 = NULL; + + if (dst) + rt6 = container_of(dst, struct rt6_info, dst); + + return rt6; +} /* * Store a destination cache entry in a socket diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index dd7608cf1d72..5acb54405b10 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -399,6 +399,24 @@ relookup_failed: return ERR_PTR(err); } +static int icmp6_iif(const struct sk_buff *skb) +{ + int iif = skb->dev->ifindex; + + /* for local traffic to local address, skb dev is the loopback + * device. Check if there is a dst attached to the skb and if so + * get the real device index. + */ + if (unlikely(iif == LOOPBACK_IFINDEX)) { + const struct rt6_info *rt6 = skb_rt6_info(skb); + + if (rt6) + iif = rt6->rt6i_idev->dev->ifindex; + } + + return iif; +} + /* * Send an ICMP message in response to a packet in error */ @@ -460,18 +478,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, */ if (__ipv6_addr_needs_scope_id(addr_type)) { - iif = skb->dev->ifindex; - - /* for local packets, get the real device index */ - if (iif == LOOPBACK_IFINDEX) { - dst = skb_dst(skb); - if (dst) { - struct rt6_info *rt; - - rt = container_of(dst, struct rt6_info, dst); - iif = rt->rt6i_idev->dev->ifindex; - } - } + iif = icmp6_iif(skb); } else { dst = skb_dst(skb); iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); @@ -694,7 +701,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb) fl6.daddr = ipv6_hdr(skb)->saddr; if (saddr) fl6.saddr = *saddr; - fl6.flowi6_oif = skb->dev->ifindex; + fl6.flowi6_oif = icmp6_iif(skb); fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; fl6.flowi6_mark = mark; fl6.flowi6_uid = sock_net_uid(net, NULL); -- 2.20.1