From 0780b4145634c3e8d69905dc5d2695d1207130df Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Fri, 11 Dec 2020 15:26:38 +0100 Subject: [PATCH] inet_ecn: Use csum16_add() helper for IP_ECN_set_* helpers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Jakub pointed out that the IP_ECN_set* helpers basically open-code csum16_add(), so let's switch them over to using the helper instead. v2: - Use __be16 for check_add stack variable in IP_ECN_set_ce() (kbot) v3: - Turns out we need __force casts to do arithmetic on __be16 types Reported-by: Jakub Kicinski Tested-by: Jonathan Morton Tested-by: Pete Heist Signed-off-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20201211142638.154780-1-toke@redhat.com Signed-off-by: Jakub Kicinski --- include/net/inet_ecn.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h index 563457fec557..ba77f47ef61e 100644 --- a/include/net/inet_ecn.h +++ b/include/net/inet_ecn.h @@ -8,6 +8,7 @@ #include #include +#include enum { INET_ECN_NOT_ECT = 0, @@ -75,8 +76,8 @@ static inline void INET_ECN_dontxmit(struct sock *sk) static inline int IP_ECN_set_ce(struct iphdr *iph) { - u32 check = (__force u32)iph->check; u32 ecn = (iph->tos + 1) & INET_ECN_MASK; + __be16 check_add; /* * After the last operation we have (in binary): @@ -93,23 +94,20 @@ static inline int IP_ECN_set_ce(struct iphdr *iph) * INET_ECN_ECT_1 => check += htons(0xFFFD) * INET_ECN_ECT_0 => check += htons(0xFFFE) */ - check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn); + check_add = (__force __be16)((__force u16)htons(0xFFFB) + + (__force u16)htons(ecn)); - iph->check = (__force __sum16)(check + (check>=0xFFFF)); + iph->check = csum16_add(iph->check, check_add); iph->tos |= INET_ECN_CE; return 1; } static inline int IP_ECN_set_ect1(struct iphdr *iph) { - u32 check = (__force u32)iph->check; - if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0) return 0; - check += (__force u16)htons(0x1); - - iph->check = (__force __sum16)(check + (check>=0xFFFF)); + iph->check = csum16_add(iph->check, htons(0x1)); iph->tos ^= INET_ECN_MASK; return 1; }