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/icmp.c | |
| parent | ipv4: Show that ip_send_reply() is purely unicast routine. (diff) | |
| download | linux-dev-35ebf65e851c6d9731abc6362b189858eb59f4d3.tar.xz linux-dev-35ebf65e851c6d9731abc6362b189858eb59f4d3.zip | |
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/icmp.c')
| -rw-r--r-- | net/ipv4/icmp.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 49a74cc79dc8..4bce5a2830aa 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -95,6 +95,7 @@ #include <net/checksum.h> #include <net/xfrm.h> #include <net/inet_common.h> +#include <net/ip_fib.h> /* * Build xmit assembly blocks @@ -333,7 +334,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; - __be32 daddr; + __be32 daddr, saddr; if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb)) return; @@ -347,6 +348,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) inet->tos = ip_hdr(skb)->tos; daddr = ipc.addr = ip_hdr(skb)->saddr; + saddr = fib_compute_spec_dst(skb); ipc.opt = NULL; ipc.tx_flags = 0; if (icmp_param->replyopts.opt.opt.optlen) { @@ -356,7 +358,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) } memset(&fl4, 0, sizeof(fl4)); fl4.daddr = daddr; - fl4.saddr = rt->rt_spec_dst; + fl4.saddr = saddr; fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); fl4.flowi4_proto = IPPROTO_ICMP; security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); |