[PATCH bpf-next v2 1/2] bpf: Allow IP_TRANSPARENT and IPV6_TRANSPARENT in bpf_{set,get}sockopt()

Currently, bpf_setsockopt() and bpf_getsockopt() for SOL_IP and SOL_IPV6
only allow a small subset of socket options (such as IP_TOS,
IPV6_TCLASS, and IPV6_AUTOFLOWLABEL). Calling bpf_setsockopt() with
IP_TRANSPARENT or IPV6_TRANSPARENT fails with -EINVAL.

Transparent proxying (TPROXY) and related networking components often
rely on IP_TRANSPARENT and IPV6_TRANSPARENT to enable binding sockets
to non-local IP addresses.

Allow IP_TRANSPARENT for SOL_IP in sol_ip_sockopt() and
IPV6_TRANSPARENT for SOL_IPV6 in sol_ipv6_sockopt().

Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Tested-by: Anubhav Singh <redacted>
Signed-off-by: Shivaji Kant <redacted>
---
 net/core/filter.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index c21c1daecf9d..04a9f9d8d07b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c

@@ -5645,6 +5645,7 @@ static int sol_ip_sockopt(struct sock *sk, int optname,
 
 	switch (optname) {
 	case IP_TOS:
+	case IP_TRANSPARENT:
 		if (*optlen != sizeof(int))
 			return -EINVAL;
 		break;

@@ -5671,6 +5672,7 @@ static int sol_ipv6_sockopt(struct sock *sk, int optname,
 	switch (optname) {
 	case IPV6_TCLASS:
 	case IPV6_AUTOFLOWLABEL:
+	case IPV6_TRANSPARENT:
 		if (*optlen != sizeof(int))
 			return -EINVAL;
 		break;

-- 
2.55.0.508.g3f0d502094-goog