From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy2-f43.google.com (mail-dy2-f43.google.com [74.125.229.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C439031F9B5 for ; Fri, 2 Oct 2026 04:22:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.229.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790914933; cv=none; b=NkLYetinBWYzJIL3bOYndC++Nl1gy7DL7KHg9rfSLhg6gEOlImcuMMWowvg6wdaC/7kp7hzRiRyDg5mkTI9dn9RsnWH08l6FVXh1DfK/+8ZgTSX6kan9TnFXLO62SNW2/77YoKPmrdhS5v79Sfkz0oB5+sjQS0V75kNfjBzwXM8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790914933; c=relaxed/simple; bh=cCGtKzRan8BWBEBX1JfJ3AgQYo8AGQ9XZRDmtPnG1yY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=bKfL3AEwSqMMvswdab1XUdca9sUtgLHP5I86lQRD83xI00ZbKwqZVG8CIkEVAlm/ajsJUmnlEtgg3c9JOTKeo2PJCQLTx+THzGbWrA11/oiOxV7vHffYAkKiK83itDOLUxP2Du41YQVoBbdLCWztXmow0iVzmKceAefqN/Uo2Sg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=eNMiMFIL; arc=none smtp.client-ip=74.125.229.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eNMiMFIL" Received: by mail-dy2-f43.google.com with SMTP id 5a478bee46e88-34b223602d7so2861765eec.2 for ; Thu, 01 Oct 2026 21:22:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790914931; x=1791519731; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=Xq7JBmYQfpiyGGj6KWk3jb5GoLIoazeQmys5Q46VZRg=; b=eNMiMFILS9TRLeBm94BHfOP2/9/SyW0OJPDkYOtazkMtdYGufwgE6/O0VSWD0vBApq bh7jv4TTRYkEsQNuvtMDg/Vjuyngw5sW4nR3LtJmIXYuviBvkM9GGBdE/AV8VyPyZMrJ rGelIaGIoXka+wVa2mJr6J/iH2qkOGs4yY6cHzIKsf1NRfDP8cZd6cQwsF/zeD6dJxSk rCiX0zvkeMy2HpNq6dBGRZ+Lf3fRw+5DSh7emeTNC49Wux86NDocQwBzaxquevPpp8P2 RvR8CymX+rt+M024v5lLa2z3OFHE2oucZxUmgVRXAHKsXG4jGQCfdTNB2F48JCumqkvR FhoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790914931; x=1791519731; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Xq7JBmYQfpiyGGj6KWk3jb5GoLIoazeQmys5Q46VZRg=; b=UfkJZ/TbeyIdtplUciTBmufVpD7Zq2bTDQ80YVO3Q+R8PJaA/fr6uEhLkNtpytkra3 2gIgnHlKrL/ESTweIct4UaMDn0r+frLz5LAjaOcR5bUVs6KoH7otsk8DHT2Egn2PjZaI f0D6VYkTPO6oGpiuZLthkvdNfp3QEHwo7ITlWc1JgRIvU16DCCN/GclSu9/QwpXLSrCG 0KCNYxEZWvTUQ2g8OrM30/8OGtudvmxkkFec8M1zbrUR1RPpw8XPZwAUwOpC7+8bMMFt CVQnNhEnbYNOxwX+cLAvnf9lwu3+fRhVr8q5GmzcLsoY6f/RzAxPNZyYwTESywsnl0VB o4eQ== X-Forwarded-Encrypted: i=1; AKwUvBww64mR6nsu56KGElav/GP3sAGUswjLhrBGAXCh28yWhydPWKA0OlgK5W3m+UuQB6Pjdoo=@vger.kernel.org X-Gm-Message-State: AFq9FYJzIk3IzWLKnK6K7uvrYY+fqY8HFZWF4tIp339cYX10Bsjxt+TR qMpPwtqIAHOdDPBKkuyg3eokJD3DjyDU5eNEublKkH+viX985sZOLKtB X-Gm-Gg: AYBFou1ZfIriq83BnwVY5TNsI90kwa5qUnhI5v+TF8CeUszb2E0GpPQpfaIcfLsKYuA GBs/ttSa2kfHkz4qh3pdZoCvdJzmMp7CgAUhSevPRHdoFXl9xHIXcGJI6tlq/widcx+HPOQ2sII gtMqzCR9JtkfX/OHU4WXkDGk7h1entdHH+m0qTIMbew3whu2kAomNIlfssfh8aNhn4K8c19Y3su xACR+i2bz7TvactdzJQ2YusiDFJ6tyNThgLpD0nBtUzLwhK+miMtBHNewZgq1nlq2nHiGLPwT+a R/AgSk0MDFommJVYpyS38lpVvxlj7gkChhEZ9vKssBHL8NSTKngmYom9ITixydchVnISJ/et4Wk w6k+USLeWIpQxVYtyhEHLEw4H3MHTDgEUJbGkARd3tI0dodLZm4+kx2Fv0nScKpsGnxWQSYKegr X8PC9vz6RxDmLbYTHohOKsr2wqu47O1K3AmNvuv0Sm4HZxgWjLQry3m3do/8GJQEn4J28yy4ozy eon9KUfLJnhV/jxrsLMN1dp3Lc4DuVKFx2g9VPKU42ucx7PJzLV7sABS+BWxOicCGD/hAEB4jaq LpNzZPEKJYHPJYTHuei6CiGblzPypbOvNlVm1oSBwdc= X-Received: by 2002:a05:7300:7fa8:b0:34e:f967:8cfa with SMTP id 5a478bee46e88-34f21990e24mr2294841eec.32.1790914930420; Thu, 01 Oct 2026 21:22:10 -0700 (PDT) Received: from ramen-dev-security-2.asia-south1-c.c.ramen-dev-345017.internal (90.156.200.35.bc.googleusercontent.com. [35.200.156.90]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-34f15019999sm2526734eec.29.2026.10.01.21.22.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2026 21:22:09 -0700 (PDT) From: Anil Kaushik To: ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, kuba@kernel.org, hawk@kernel.org, john.fastabend@gmail.com, andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com, shuah@kernel.org Cc: sdf@fomichev.me, ihor.solodrai@linux.dev, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org, emil@etsalapatis.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Anil Kaushik Subject: [PATCH bpf-next v2] selftests/bpf: add XDP test for per-flow LRU_HASH window updates Date: Fri, 2 Oct 2026 04:22:01 +0000 Message-Id: <20261002042201.3483076-1-anilkaushikwireless@gmail.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The LRU_HASH selftests (test_lru_map) exercise BPF_MAP_TYPE_LRU_HASH only from the syscall side. There is no coverage of an XDP program updating an LRU_HASH map on the data path: inserting an entry with BPF_NOEXIST on first sight of a flow, then updating a bounded array inside the map value using a runtime (modulo) index. That pattern is common in XDP flow-tracking programs and stresses two things worth testing together: the verifier's bounds checking of a value-internal array indexed by a runtime value, and per-flow key isolation in an LRU map driven from XDP. Add an XDP program that keys an LRU_HASH by the TCP/IPv4 5-tuple and records packet lengths into value->pkt_len[seq % AGGREGATION_WINDOW], plus a test_progs case driven by bpf_prog_test_run that checks: - wrap: seq advances and the bounded array wraps, with the runtime index accepted by the verifier; - trunc: a short (parse-failing) packet neither inserts a new entry nor mutates an existing one; - isolate: two distinct 5-tuples get independent entries. Selftest only; no kernel change. Signed-off-by: Anil Kaushik --- v2: - CC the XDP / BPF-selftests maintainers and reviewers; v1 was sent to the lists only and received no review. - Rewrite the commit message to explain the coverage gap and intent. - No change to the test code. v1: https://lore.kernel.org/netdev/20260917135433.2260048-1-anilkaushikwireless@gmail.com/ .../selftests/bpf/prog_tests/xdp_lru_window.c | 168 ++++++++++++++++++ .../selftests/bpf/progs/xdp_lru_window.c | 81 +++++++++ tools/testing/selftests/bpf/xdp_lru_window.h | 28 +++ 3 files changed, 277 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_lru_window.c create mode 100644 tools/testing/selftests/bpf/progs/xdp_lru_window.c create mode 100644 tools/testing/selftests/bpf/xdp_lru_window.h diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_lru_window.c b/tools/testing/selftests/bpf/prog_tests/xdp_lru_window.c new file mode 100644 index 000000000..55175c216 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/xdp_lru_window.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include "xdp_lru_window.h" +#include "xdp_lru_window.skel.h" + +#define SRC_IP 0x0a000001 +#define DST_IP 0x0a000002 +#define SRC_PORT 12345 +#define DST_PORT 80 +#define ALT_DST_PORT 81 + +static struct xdp_lru_window *skel; +static int prog_fd, map_fd; + +static void fill_pkt(struct ipv4_packet *pkt, __u16 dport) +{ + *pkt = pkt_v4; + pkt->iph.saddr = htonl(SRC_IP); + pkt->iph.daddr = htonl(DST_IP); + pkt->tcp.source = htons(SRC_PORT); + pkt->tcp.dest = htons(dport); +} + +static void fill_key(struct xdp_lru_window_key *key, __u16 dport) +{ + memset(key, 0, sizeof(*key)); + key->saddr = htonl(SRC_IP); + key->daddr = htonl(DST_IP); + key->sport = htons(SRC_PORT); + key->dport = htons(dport); + key->proto = IPPROTO_TCP; +} + +static int run_pkt(const void *data, __u32 len, int *retval) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = data, + .data_size_in = len, + .repeat = 1, + ); + int err; + + err = bpf_prog_test_run_opts(prog_fd, &opts); + if (!ASSERT_OK(err, "test_run")) + return err; + if (retval) + *retval = opts.retval; + return 0; +} + +static int inject(int n, __u16 dport) +{ + struct ipv4_packet pkt; + int i, retval; + + fill_pkt(&pkt, dport); + for (i = 0; i < n; i++) { + if (run_pkt(&pkt, sizeof(pkt), &retval)) + return -1; + if (!ASSERT_EQ(retval, XDP_PASS, "retval")) + return -1; + } + return 0; +} + +static void reset_map(void) +{ + struct xdp_lru_window_key key, next; + int err; + + err = bpf_map_get_next_key(map_fd, NULL, &next); + while (!err) { + key = next; + err = bpf_map_get_next_key(map_fd, &key, &next); + bpf_map_delete_elem(map_fd, &key); + } +} + +static void test_one_and_wrap(void) +{ + struct xdp_lru_window_state st; + struct xdp_lru_window_key key; + int i, n; + + reset_map(); + if (inject(1, DST_PORT)) + return; + fill_key(&key, DST_PORT); + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &st), "lookup")) + return; + ASSERT_EQ(st.seq, 1, "seq"); + ASSERT_EQ(st.pkt_len[0], sizeof(struct ipv4_packet), "len0"); + + n = AGGREGATION_WINDOW + 5; + if (inject(n - 1, DST_PORT)) + return; + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &st), "lookup wrap")) + return; + ASSERT_EQ(st.seq, n, "seq wrap"); + for (i = 0; i < AGGREGATION_WINDOW; i++) + ASSERT_EQ(st.pkt_len[i], sizeof(struct ipv4_packet), "slot"); +} + +static void test_trunc(void) +{ + struct xdp_lru_window_state before, after; + struct xdp_lru_window_key key, next; + unsigned char short_pkt[sizeof(struct ethhdr)] = {}; + int err, retval; + + reset_map(); + err = run_pkt(short_pkt, sizeof(short_pkt), &retval); + if (err) + return; + ASSERT_EQ(retval, XDP_PASS, "trunc retval"); + err = bpf_map_get_next_key(map_fd, NULL, &next); + ASSERT_EQ(err, -ENOENT, "trunc no insert"); + + if (inject(1, DST_PORT)) + return; + fill_key(&key, DST_PORT); + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &before), "setup")) + return; + if (run_pkt(short_pkt, sizeof(short_pkt), &retval)) + return; + ASSERT_EQ(retval, XDP_PASS, "trunc2 retval"); + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &after), "after")) + return; + ASSERT_EQ(after.seq, before.seq, "trunc no mutate"); +} + +static void test_isolate(void) +{ + struct xdp_lru_window_state a, b; + struct xdp_lru_window_key key; + + reset_map(); + if (inject(2, DST_PORT) || inject(1, ALT_DST_PORT)) + return; + fill_key(&key, DST_PORT); + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &a), "flow a")) + return; + fill_key(&key, ALT_DST_PORT); + if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &b), "flow b")) + return; + ASSERT_EQ(a.seq, 2, "seq a"); + ASSERT_EQ(b.seq, 1, "seq b"); +} + +void test_xdp_lru_window(void) +{ + skel = xdp_lru_window__open_and_load(); + if (!ASSERT_OK_PTR(skel, "open_and_load")) + return; + + prog_fd = bpf_program__fd(skel->progs.xdp_lru_window); + map_fd = bpf_map__fd(skel->maps.flow_table); + + if (test__start_subtest("wrap")) + test_one_and_wrap(); + if (test__start_subtest("trunc")) + test_trunc(); + if (test__start_subtest("isolate")) + test_isolate(); + + xdp_lru_window__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/xdp_lru_window.c b/tools/testing/selftests/bpf/progs/xdp_lru_window.c new file mode 100644 index 000000000..27aa1509e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/xdp_lru_window.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include "xdp_lru_window.h" + +#ifndef ETH_P_IP +#define ETH_P_IP 0x0800 +#endif + +#ifndef EEXIST +#define EEXIST 17 +#endif + +struct { + __uint(type, BPF_MAP_TYPE_LRU_HASH); + __uint(max_entries, XDP_LRU_WINDOW_FLOWS); + __type(key, struct xdp_lru_window_key); + __type(value, struct xdp_lru_window_state); +} flow_table SEC(".maps"); + +SEC("xdp") +int xdp_lru_window(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + struct xdp_lru_window_state init, *st; + struct xdp_lru_window_key key; + struct ethhdr *eth; + struct iphdr *iph; + struct tcphdr *th; + __u32 idx, pkt_len; + int err; + + eth = data; + if ((void *)(eth + 1) > data_end) + return XDP_PASS; + if (eth->h_proto != bpf_htons(ETH_P_IP)) + return XDP_PASS; + + iph = (void *)(eth + 1); + if ((void *)(iph + 1) > data_end) + return XDP_PASS; + if (iph->protocol != IPPROTO_TCP) + return XDP_PASS; + + th = (void *)(iph + 1); + if ((void *)(th + 1) > data_end) + return XDP_PASS; + + __builtin_memset(&key, 0, sizeof(key)); + key.saddr = iph->saddr; + key.daddr = iph->daddr; + key.sport = th->source; + key.dport = th->dest; + key.proto = iph->protocol; + pkt_len = data_end - data; + + st = bpf_map_lookup_elem(&flow_table, &key); + if (!st) { + __builtin_memset(&init, 0, sizeof(init)); + err = bpf_map_update_elem(&flow_table, &key, &init, + BPF_NOEXIST); + if (err && err != -EEXIST) + return XDP_PASS; + st = bpf_map_lookup_elem(&flow_table, &key); + if (!st) + return XDP_PASS; + } + + idx = st->seq % AGGREGATION_WINDOW; + barrier_var(idx); + if (idx >= AGGREGATION_WINDOW) + return XDP_PASS; + + st->pkt_len[idx] = pkt_len; + st->seq++; + return XDP_PASS; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/xdp_lru_window.h b/tools/testing/selftests/bpf/xdp_lru_window.h new file mode 100644 index 000000000..78434045c --- /dev/null +++ b/tools/testing/selftests/bpf/xdp_lru_window.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __XDP_LRU_WINDOW_H +#define __XDP_LRU_WINDOW_H + +/* + * ABI for the XDP LRU rolling-window selftest. Existing test_lru_map + * coverage never enters XDP; XDP parse tests do not store a modulo + * index into an LRU map value. + */ + +#define AGGREGATION_WINDOW 50 +#define XDP_LRU_WINDOW_FLOWS 64 + +struct xdp_lru_window_key { + __be32 saddr; + __be32 daddr; + __be16 sport; + __be16 dport; + __u8 proto; + __u8 pad[3]; +}; + +struct xdp_lru_window_state { + __u32 seq; + __u32 pkt_len[AGGREGATION_WINDOW]; +}; + +#endif /* __XDP_LRU_WINDOW_H */ -- 2.25.1