diff options
| author | David S. Miller <davem@davemloft.net> | 2012-06-28 03:59:11 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-06-28 03:59:11 -0700 |
| commit | 35ebf65e851c6d9731abc6362b189858eb59f4d3 (patch) | |
| tree | 2e78c2c81bc72aeeb172484996cdff268f0111a2 /net/ipv4/ip_sockglue.c | |
| parent | 70e7341673a47fb1525cfc7d6651cc98b5348928 (diff) | |
ipv4: Create and use fib_compute_spec_dst() helper.
The specific destination is the host we direct unicast replies to.
Usually this is the original packet source address, but if we are
responding to a multicast or broadcast packet we have to use something
different.
Specifically we must use the source address we would use if we were to
send a packet to the unicast source of the original packet.
The routing cache precomputes this value, but we want to remove that
precomputation because it creates a hard dependency on the expensive
rpfilter source address validation which we'd like to make cheaper.
There are only three places where this matters:
1) ICMP replies.
2) pktinfo CMSG
3) IP options
Now there will be no real users of rt->rt_spec_dst and we can simply
remove it altogether.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_sockglue.c')
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 0d11f234d61..de29f46f68b 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -40,6 +40,7 @@ #if IS_ENABLED(CONFIG_IPV6) #include <net/transp_v6.h> #endif +#include <net/ip_fib.h> #include <linux/errqueue.h> #include <asm/uaccess.h> @@ -1019,8 +1020,8 @@ e_inval: * @sk: socket * @skb: buffer * - * To support IP_CMSG_PKTINFO option, we store rt_iif and rt_spec_dst - * in skb->cb[] before dst drop. + * To support IP_CMSG_PKTINFO option, we store rt_iif and specific + * destination in skb->cb[] before dst drop. * This way, receiver doesnt make cache line misses to read rtable. */ void ipv4_pktinfo_prepare(struct sk_buff *skb) @@ -1030,7 +1031,7 @@ void ipv4_pktinfo_prepare(struct sk_buff *skb) if (rt) { pktinfo->ipi_ifindex = rt->rt_iif; - pktinfo->ipi_spec_dst.s_addr = rt->rt_spec_dst; + pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb); } else { pktinfo->ipi_ifindex = 0; pktinfo->ipi_spec_dst.s_addr = 0; |