ipv4: Unmask upper DSCP bits in ip_send_unicast_reply()

The function calls flowi4_init_output() to initialize an IPv4 flow key with which it then performs a FIB lookup using ip_route_output_flow(). 'arg->tos' with which the TOS value in the IPv4 flow key (flowi4_tos) is initialized contains the full DS field. Unmask the upper DSCP bits so that in the future the FIB lookup could be performed according to the full DSCP value. Signed-off-by: Ido Schimmel <[email protected]> Reviewed-by: Guillaume Nault <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mj22226 · Aug 31, 2024 · 13f6538 · 13f6538
1 parent b261b2c
commit 13f6538
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
@@ -77,6 +77,7 @@
 #include <net/inetpeer.h>
 #include <net/inet_ecn.h>
 #include <net/lwtunnel.h>
+#include <net/inet_dscp.h>
 #include <linux/bpf-cgroup.h>
 #include <linux/igmp.h>
 #include <linux/netfilter_ipv4.h>
@@ -1621,7 +1622,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 
 	flowi4_init_output(&fl4, oif,
 			   IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark,
-			   RT_TOS(arg->tos),
+			   arg->tos & INET_DSCP_MASK,
 			   RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
 			   ip_reply_arg_flowi_flags(arg),
 			   daddr, saddr,