[PATCH bpf-next v3 1/2] bpf: Fix bpf_get/setsockopt to tos not take effect when TCP over IPv4 via INET6 API

[Feng zhou]

From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>

when TCP over IPv4 via INET6 API, bpf_get/setsockopt with ipv4 will
fail, because sk->sk_family is AF_INET6. With ipv6 will success, not
take effect, because inet_csk(sk)->icsk_af_ops is ipv6_mapped and
use ip_queue_xmit, inet_sk(sk)->tos.

Bpf_get/setsockopt use sk_is_inet() helper to fix this case.

Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
---
 net/core/filter.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index e4a4454df5f9..90f4dbb8d2b5 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5399,7 +5399,12 @@ static int sol_ip_sockopt(struct sock *sk, int optname,
 			  char *optval, int *optlen,
 			  bool getopt)
 {
-	if (sk->sk_family != AF_INET)
+
+	/*
+	 * SOL_IP socket options are available on AF_INET and AF_INET6, for
+	 * example, TCP over IPv4 via INET6 API.
+	 */
+	if (!sk_is_inet(sk))
 		return -EINVAL;
 
 	switch (optname) {
-- 
2.30.2