selftests: net: move common xdp.py functions into lib

This moves a few functions which can be useful to other python programs
that manipulate XDP programs. This also refactors xdp.py to use the
refactored functions.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
Link: https://patch.msgid.link/20260325201139.2501937-6-carges@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/lib/py/__init__.py

@@ -24,6 +24,7 @@ try:
     from net.lib.py import CmdExitFailure
     from net.lib.py import bkg, cmd, bpftool, bpftrace, defer, ethtool, \
         fd_read_timeout, ip, rand_port, rand_ports, wait_port_listen, wait_file
+    from net.lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
     from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx
     from net.lib.py import ksft_disruptive, ksft_exit, ksft_pr, ksft_run, \
         ksft_setup, ksft_variants, KsftNamedVariant
@@ -37,6 +38,7 @@ try:
                "bkg", "cmd", "bpftool", "bpftrace", "defer", "ethtool",
                "fd_read_timeout", "ip", "rand_port", "rand_ports",
                "wait_port_listen", "wait_file",
+               "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
                "KsftSkipEx", "KsftFailEx", "KsftXfailEx",
                "ksft_disruptive", "ksft_exit", "ksft_pr", "ksft_run",
                "ksft_setup", "ksft_variants", "KsftNamedVariant",

tools/testing/selftests/drivers/net/xdp.py

@@ -16,7 +16,8 @@ from lib.py import KsftNamedVariant, ksft_variants
 from lib.py import KsftFailEx, NetDrvEpEnv
 from lib.py import EthtoolFamily, NetdevFamily, NlError
 from lib.py import bkg, cmd, rand_port, wait_port_listen
-from lib.py import ip, bpftool, defer
+from lib.py import ip, defer
+from lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
 
 
 class TestConfig(Enum):
@@ -122,47 +123,11 @@ def _load_xdp_prog(cfg, bpf_info):
     xdp_info = ip(f"-d link show dev {cfg.ifname}", json=True)[0]
     prog_info["id"] = xdp_info["xdp"]["prog"]["id"]
     prog_info["name"] = xdp_info["xdp"]["prog"]["name"]
-    prog_id = prog_info["id"]
-
-    map_ids = bpftool(f"prog show id {prog_id}", json=True)["map_ids"]
-    prog_info["maps"] = {}
-    for map_id in map_ids:
-        name = bpftool(f"map show id {map_id}", json=True)["name"]
-        prog_info["maps"][name] = map_id
+    prog_info["maps"] = bpf_prog_map_ids(prog_info["id"])
 
     return prog_info
 
 
-def format_hex_bytes(value):
-    """
-    Helper function that converts an integer into a formatted hexadecimal byte string.
-
-    Args:
-        value: An integer representing the number to be converted.
-
-    Returns:
-        A string representing hexadecimal equivalent of value, with bytes separated by spaces.
-    """
-    hex_str = value.to_bytes(4, byteorder='little', signed=True)
-    return ' '.join(f'{byte:02x}' for byte in hex_str)
-
-
-def _set_xdp_map(map_name, key, value):
-    """
-    Updates an XDP map with a given key-value pair using bpftool.
-
-    Args:
-        map_name: The name of the XDP map to update.
-        key: The key to update in the map, formatted as a hexadecimal string.
-        value: The value to associate with the key, formatted as a hexadecimal string.
-    """
-    key_formatted = format_hex_bytes(key)
-    value_formatted = format_hex_bytes(value)
-    bpftool(
-        f"map update name {map_name} key hex {key_formatted} value hex {value_formatted}"
-    )
-
-
 def _get_stats(xdp_map_id):
     """
     Retrieves and formats statistics from an XDP map.
@@ -177,25 +142,11 @@ def _get_stats(xdp_map_id):
     Raises:
         KsftFailEx: If the stats retrieval fails.
     """
-    stats_dump = bpftool(f"map dump id {xdp_map_id}", json=True)
-    if not stats_dump:
+    stats = bpf_map_dump(xdp_map_id)
+    if not stats:
         raise KsftFailEx(f"Failed to get stats for map {xdp_map_id}")
 
-    stats_formatted = {}
-    for key in range(0, 5):
-        val = stats_dump[key]["formatted"]["value"]
-        if stats_dump[key]["formatted"]["key"] == XDPStats.RX.value:
-            stats_formatted[XDPStats.RX.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.PASS.value:
-            stats_formatted[XDPStats.PASS.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.DROP.value:
-            stats_formatted[XDPStats.DROP.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.TX.value:
-            stats_formatted[XDPStats.TX.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.ABORT.value:
-            stats_formatted[XDPStats.ABORT.value] = val
-
-    return stats_formatted
+    return stats
 
 
 def _test_pass(cfg, bpf_info, msg_sz):
@@ -211,8 +162,8 @@ def _test_pass(cfg, bpf_info, msg_sz):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.PASS.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.PASS.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     ksft_eq(_test_udp(cfg, port, msg_sz), True, "UDP packet exchange failed")
     stats = _get_stats(prog_info["maps"]["map_xdp_stats"])
@@ -258,8 +209,8 @@ def _test_drop(cfg, bpf_info, msg_sz):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.DROP.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.DROP.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     ksft_eq(_test_udp(cfg, port, msg_sz), False, "UDP packet exchange should fail")
     stats = _get_stats(prog_info["maps"]["map_xdp_stats"])
@@ -305,8 +256,8 @@ def _test_xdp_native_tx(cfg, bpf_info, payload_lens):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.TX.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.TX.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     expected_pkts = 0
     for payload_len in payload_lens:
@@ -454,15 +405,15 @@ def _test_xdp_native_tail_adjst(cfg, pkt_sz_lst, offset_lst):
     prog_info = _load_xdp_prog(cfg, bpf_info)
 
     # Configure the XDP map for tail adjustment
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.TAIL_ADJST.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.TAIL_ADJST.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     for offset in offset_lst:
         tag = format(random.randint(65, 90), "02x")
 
-        _set_xdp_map("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
+        bpf_map_set("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
         if offset > 0:
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
 
         for pkt_sz in pkt_sz_lst:
             test_str = "".join(random.choice(string.ascii_lowercase) for _ in range(pkt_sz))
@@ -574,8 +525,8 @@ def _test_xdp_native_head_adjst(cfg, prog, pkt_sz_lst, offset_lst):
     prog_info = _load_xdp_prog(cfg, BPFProgInfo(prog, "xdp_native.bpf.o", "xdp.frags", 9000))
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.HEAD_ADJST.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.HEAD_ADJST.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     hds_thresh = get_hds_thresh(cfg)
     for offset in offset_lst:
@@ -595,11 +546,8 @@ def _test_xdp_native_head_adjst(cfg, prog, pkt_sz_lst, offset_lst):
             test_str = ''.join(random.choice(string.ascii_lowercase) for _ in range(pkt_sz))
             tag = format(random.randint(65, 90), '02x')
 
-            _set_xdp_map("map_xdp_setup",
-                     TestConfig.ADJST_OFFSET.value,
-                     offset)
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
 
             recvd_str = _exchg_udp(cfg, port, test_str)
 
@@ -691,8 +639,8 @@ def test_xdp_native_qstats(cfg, act):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, act.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, act.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     # Discard the input, but we need a listener to avoid ICMP errors
     rx_udp = f"socat -{cfg.addr_ipver} -T 2 -u UDP-RECV:{port},reuseport " + \

tools/testing/selftests/net/lib/py/__init__.py

@@ -15,6 +15,7 @@ from .nsim import NetdevSim, NetdevSimDev
 from .utils import CmdExitFailure, fd_read_timeout, cmd, bkg, defer, \
     bpftool, ip, ethtool, bpftrace, rand_port, rand_ports, wait_port_listen, \
     wait_file, tool
+from .bpf import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
 from .ynl import NlError, NlctrlFamily, YnlFamily, \
     EthtoolFamily, NetdevFamily, RtnlFamily, RtnlAddrFamily
 from .ynl import NetshaperFamily, DevlinkFamily, PSPFamily, Netlink
@@ -29,6 +30,7 @@ __all__ = ["KSRC",
            "CmdExitFailure", "fd_read_timeout", "cmd", "bkg", "defer",
            "bpftool", "ip", "ethtool", "bpftrace", "rand_port", "rand_ports",
            "wait_port_listen", "wait_file", "tool",
+           "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
            "NetdevSim", "NetdevSimDev",
            "NetshaperFamily", "DevlinkFamily", "PSPFamily", "NlError",
            "YnlFamily", "EthtoolFamily", "NetdevFamily", "RtnlFamily",

tools/testing/selftests/net/lib/py/bpf.py

@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+BPF helper utilities for kernel selftests.
+
+Provides common operations for interacting with BPF maps and programs
+via bpftool, used by XDP and other BPF-based test files.
+"""
+
+from .utils import bpftool
+
+def _format_hex_bytes(value):
+    """
+    Helper function that converts an integer into a formatted hexadecimal byte string.
+
+    Args:
+        value: An integer representing the number to be converted.
+
+    Returns:
+        A string representing hexadecimal equivalent of value, with bytes separated by spaces.
+    """
+    hex_str = value.to_bytes(4, byteorder='little', signed=True)
+    return ' '.join(f'{byte:02x}' for byte in hex_str)
+
+
+def bpf_map_set(map_name, key, value):
+    """
+    Updates an XDP map with a given key-value pair using bpftool.
+
+    Args:
+        map_name: The name of the XDP map to update.
+        key: The key to update in the map, formatted as a hexadecimal string.
+        value: The value to associate with the key, formatted as a hexadecimal string.
+    """
+    key_formatted = _format_hex_bytes(key)
+    value_formatted = _format_hex_bytes(value)
+    bpftool(
+        f"map update name {map_name} key hex {key_formatted} value hex {value_formatted}"
+    )
+
+def bpf_map_dump(map_id):
+    """Dump all entries of a BPF array map.
+
+    Args:
+        map_id: Numeric map ID (as returned by bpftool prog show).
+
+    Returns:
+        A dict mapping formatted key (int) to formatted value (int).
+    """
+    raw = bpftool(f"map dump id {map_id}", json=True)
+    return {e["formatted"]["key"]: e["formatted"]["value"] for e in raw}
+
+
+def bpf_prog_map_ids(prog_id):
+    """Get the map name-to-ID mapping for a loaded BPF program.
+
+    Args:
+        prog_id: Numeric program ID.
+
+    Returns:
+        A dict mapping map name (str) to map ID (int).
+    """
+    map_ids = bpftool(f"prog show id {prog_id}", json=True)["map_ids"]
+    maps = {}
+    for mid in map_ids:
+        name = bpftool(f"map show id {mid}", json=True)["name"]
+        maps[name] = mid
+    return maps