net/smc: Remove validation of reserved bits in CLC Decline message

Currently SMC code is validating the reserved bits while parsing the incoming
CLC decline message & when this validation fails, its treated as a protocol
error. As a result, the SMC connection is terminated instead of falling back to
TCP. As per RFC7609[1] specs we shouldn't be validating the reserved bits that
is part of CLC message. This patch fixes this issue.

CLC Decline message format can viewed here[2].

[1] https://datatracker.ietf.org/doc/html/rfc7609#page-92
[2] https://datatracker.ietf.org/doc/html/rfc7609#page-105

Fixes: 8ade200c269f ("net/smc: add v2 format of CLC decline message")
Signed-off-by: Mahanta Jambigi <mjambigi@linux.ibm.com>
Reviewed-by: Sidraya Jayagond <sidraya@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20250902082041.98996-1-mjambigi@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 5a4db151fe9578d25bbba7f65d2862ede1c4506e..08be56dfb3f24e90c81fca7de5e52e9bbbce06fa 100644 (file)
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -426,8 +426,6 @@ smc_clc_msg_decl_valid(struct smc_clc_msg_decline *dclc)
 {
        struct smc_clc_msg_hdr *hdr = &dclc->hdr;
 
-       if (hdr->typev1 != SMC_TYPE_R && hdr->typev1 != SMC_TYPE_D)
-               return false;
        if (hdr->version == SMC_V1) {
                if (ntohs(hdr->length) != sizeof(struct smc_clc_msg_decline))
                        return false;