| Message ID | 20240821125251.1571445-8-idosch@nvidia.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 39d3628f7ceabd22385dcd6811ed4c353f7c859b |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Unmask upper DSCP bits - part 1 | expand |
On Wed, Aug 21, 2024 at 03:52:46PM +0300, Ido Schimmel wrote: > Unmask the upper DSCP bits of the DS field of the packet that triggered > the reply so that in the future the FIB lookup could be performed > according to the full DSCP value. Reviewed-by: Guillaume Nault <gnault@redhat.com>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 8b740f575da1..793e6781399a 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -293,7 +293,7 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) .flowi4_iif = LOOPBACK_IFINDEX, .flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev), .daddr = ip_hdr(skb)->saddr, - .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK, + .flowi4_tos = ip_hdr(skb)->tos & INET_DSCP_MASK, .flowi4_scope = scope, .flowi4_mark = vmark ? skb->mark : 0, };
As explained in commit 35ebf65e851c ("ipv4: Create and use fib_compute_spec_dst() helper."), the function is used - for example - to determine the source address for an ICMP reply. If we are responding to a multicast or broadcast packet, the source address is set to the source address that we would use if we were to send a packet to the unicast source of the original packet. This address is determined by performing a FIB lookup and using the preferred source address of the resulting route. Unmask the upper DSCP bits of the DS field of the packet that triggered the reply so that in the future the FIB lookup could be performed according to the full DSCP value. No functional changes intended since the upper DSCP bits are masked when comparing against the TOS selectors in FIB rules and routes. Signed-off-by: Ido Schimmel <idosch@nvidia.com> --- net/ipv4/fib_frontend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)