From ef434fae72287a9cd0f7b85ad1701b998cce800b Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Wed, 21 Aug 2024 15:52:40 +0300 Subject: [PATCH] bpf: Unmask upper DSCP bits in bpf_fib_lookup() helper The helper performs a FIB lookup according to the parameters in the 'params' argument, one of which is 'tos'. According to the test in test_tc_neigh_fib.c, it seems that BPF programs are expected to initialize the 'tos' field to the full 8 bit DS field from the IPv4 header. Unmask the upper DSCP bits before invoking the IPv4 FIB lookup APIs so that in the future the 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 Reviewed-by: Guillaume Nault Acked-by: Florian Westphal Reviewed-by: David Ahern Link: https://patch.msgid.link/20240821125251.1571445-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski --- net/core/filter.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index f3c72cf86099..89f56fac48fb 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -84,6 +84,7 @@ #include #include #include +#include #include "dev.h" @@ -5899,7 +5900,7 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params, fl4.flowi4_iif = params->ifindex; fl4.flowi4_oif = 0; } - fl4.flowi4_tos = params->tos & IPTOS_RT_MASK; + fl4.flowi4_tos = params->tos & INET_DSCP_MASK; fl4.flowi4_scope = RT_SCOPE_UNIVERSE; fl4.flowi4_flags = 0; -- 2.25.1