bpf: Add a few optnames to bpf_setsockopt

This patch adds a few optnames for bpf_setsockopt:
SO_REUSEADDR, IPV6_AUTOFLOWLABEL, TCP_MAXSEG, TCP_NODELAY,
and TCP_THIN_LINEAR_TIMEOUTS.

Thanks to the previous patches of this set, all additions can reuse
the sk_setsockopt(), do_ipv6_setsockopt(), and do_tcp_setsockopt().
The only change here is to allow them in bpf_setsockopt.

The bpf prog has been able to read all members of a sk by
using PTR_TO_BTF_ID of a sk.  The optname additions here can also be
read by the same approach.  Meaning there is a way to read
the values back.

These optnames can also be added to bpf_getsockopt() later with
another patch set that makes the bpf_getsockopt() to reuse
the sock_getsockopt(), tcp_getsockopt(), and ip[v6]_getsockopt().
Thus, this patch does not add more duplicated code to
bpf_getsockopt() now.
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061841.4181642-1-kafai@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

net/core/filter.c

@@ -5017,6 +5017,7 @@ static int sol_socket_setsockopt(struct sock *sk, int optname,
 				 char *optval, int optlen)
 {
 	switch (optname) {
+	case SO_REUSEADDR:
 	case SO_SNDBUF:
 	case SO_RCVBUF:
 	case SO_KEEPALIVE:
@@ -5093,11 +5094,14 @@ static int sol_tcp_setsockopt(struct sock *sk, int optname,
 		return -EINVAL;
 
 	switch (optname) {
+	case TCP_NODELAY:
+	case TCP_MAXSEG:
 	case TCP_KEEPIDLE:
 	case TCP_KEEPINTVL:
 	case TCP_KEEPCNT:
 	case TCP_SYNCNT:
 	case TCP_WINDOW_CLAMP:
+	case TCP_THIN_LINEAR_TIMEOUTS:
 	case TCP_USER_TIMEOUT:
 	case TCP_NOTSENT_LOWAT:
 	case TCP_SAVE_SYN:
@@ -5141,6 +5145,7 @@ static int sol_ipv6_setsockopt(struct sock *sk, int optname,
 
 	switch (optname) {
 	case IPV6_TCLASS:
+	case IPV6_AUTOFLOWLABEL:
 		if (optlen != sizeof(int))
 			return -EINVAL;
 		break;