selftests: rds: pin RDS sockets to their intended transport

The RDS selftests create AF_RDS sockets but never selects a transport,
so the transport is chosen implicitly based on network topology when
the socket is bound.  If underlying connection establishment fails, RDS
can fall back to another transport (e.g. loopback) and the test still
passes, silently bypassing the intended datapath it is meant to
exercise.

Set SO_RDS_TRANSPORT to the proper RDS_TRANS_IB or RDS_TRANS_TCP before
they are bound, so the test fails loudly if the intended transport is
unavailable rather than passing on a different path.

Signed-off-by: Allison Henderson <achender@kernel.org>
Link: https://patch.msgid.link/20260602050657.26389-3-achender@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Allison Henderson 2026-06-01 22:06:55 -07:00 committed by Jakub Kicinski
parent 6d05d3cb44
commit d2e76c5b14

View File

@ -59,6 +59,14 @@ rdma_addrs = [
OP_FLAG_TCP = 0x1
OP_FLAG_RDMA = 0x2
# from include/uapi/linux/rds.h: SO_RDS_TRANSPORT pins a socket to a
# specific RDS transport so connection setup cannot silently fall back
# to another (e.g. loopback) transport.
SOL_RDS = 276
SO_RDS_TRANSPORT = 8
RDS_TRANS_TCP = 2
RDS_TRANS_IB = 0
signal_handler_label = ""
tap_idx = 0
@ -214,11 +222,21 @@ def snd_rcv_packets(env):
netns_socket(netns_list[0], socket.AF_RDS, socket.SOCK_SEQPACKET),
netns_socket(netns_list[1], socket.AF_RDS, socket.SOCK_SEQPACKET),
]
# Pin the sockets to the TCP transport so it doesn't fail over to a
# different transport during this test
for s in sockets:
s.setsockopt(SOL_RDS, SO_RDS_TRANSPORT, RDS_TRANS_TCP)
elif flags & OP_FLAG_RDMA:
sockets = [
socket.socket(socket.AF_RDS, socket.SOCK_SEQPACKET),
socket.socket(socket.AF_RDS, socket.SOCK_SEQPACKET),
]
# Pin the sockets to the RDMA transport so it doesn't fail over to a
# different transport during this test
for s in sockets:
s.setsockopt(SOL_RDS, SO_RDS_TRANSPORT, RDS_TRANS_IB)
else:
raise RuntimeError(f"Invalid transport flag sets no transports: {flags}")