MIPS socket option (SO_*) values are wrong — setsockopt fails (e.g. busybox ping)

[retrocpugeek]

MIPS socket option (SO_*) values are wrong — setsockopt fails (e.g. busybox ping)

Describe the bug

linux_mips_socket_options (qiling/os/posix/const.py) uses generic/incorrect SO_* values. MIPS has its own numbering (arch/mips/include/uapi/asm/socket.h) where the buffer/timeout/type options live in the 0x1000 range, unlike the asm-generic values used by most arches. The table is wrong in several places:

option	table has	MIPS uapi
SO_SNDBUF	0x01	0x1001
SO_RCVBUF	0x02	0x1002
SO_SNDLOWAT	0x03	0x1003
SO_RCVLOWAT	0x04	0x1004
SO_SNDTIMEO_OLD	0x05	0x1005
SO_RCVTIMEO_OLD	0x06	0x1006
SO_OOBINLINE	0x00	0x0100
SO_REUSEPORT	0x00	0x0200

SO_RCVLOWAT = 0x04 also silently collides with SO_REUSEADDR = 0x04 (it becomes an Enum alias), and SO_TYPE/SO_ERROR are missing entirely.

Consequently a guest setsockopt(SOL_SOCKET, SO_RCVBUF, ...) aborts emulation:

NotImplementedError: Could not convert emulated socket option 4098 to a socket option name

(4098 == 0x1002 == SO_RCVBUF on MIPS.) This is hit by ordinary programs — e.g. busybox ping sets SO_RCVBUF/SO_SNDBUF right after creating its socket.

Repro (Python)

from qiling import Qiling
from qiling.const import QL_ARCH, QL_OS, QL_ENDIAN, QL_VERBOSE
from qiling.os.posix.syscall.socket import ql_syscall_socket, ql_syscall_setsockopt

ql = Qiling(code=b"\x00\x00\x00\x00", archtype=QL_ARCH.MIPS, ostype=QL_OS.LINUX,
            endian=QL_ENDIAN.EB, rootfs="examples/rootfs/mips32_linux", verbose=QL_VERBOSE.OFF)

fd = ql_syscall_socket(ql, 2, 2, 0)            # AF_INET, SOCK_DGRAM
base = 0x100000
ql.mem.map(base, 0x1000)
ql.mem.write_ptr(base, 16384, 4)
# SOL_SOCKET=0xffff, SO_RCVBUF=0x1002 on MIPS
ql_syscall_setsockopt(ql, fd, 0xffff, 0x1002, base, 4)

Without the fix this raises NotImplementedError: Could not convert emulated socket option 4098.

Expected behavior

setsockopt with the MIPS SO_* values should map to the host option and succeed, matching the kernel's MIPS SO_* numbering.

Environment

• Affects MIPS / MIPS64 (the values are shared); reproduces on any host.
• Same code area as the already-closed Socket mapping do not support "IPPROTO_TCP" level #1286 (socket-level mapping for IPPROTO_TCP).

A fix (correct the SO_* values + add the missing ones, with a regression test) is proposed in the linked PR.