From patchwork Fri Dec 15 03:07:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 13493971 X-Patchwork-Delegate: kuba@kernel.org Received: from out199-6.us.a.mail.aliyun.com (out199-6.us.a.mail.aliyun.com [47.90.199.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B94F3CA64; Fri, 15 Dec 2023 03:13:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0VyWIqbW_1702609659; Received: from j66a10360.sqa.eu95.tbsite.net(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0VyWIqbW_1702609659) by smtp.aliyun-inc.com; Fri, 15 Dec 2023 11:07:40 +0800 From: "D. Wythe" To: pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, coreteam@netfilter.org, netfilter-devel@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ast@kernel.org Subject: [RFC nf-next v1 1/2] netfilter: bpf: support prog update Date: Fri, 15 Dec 2023 11:07:32 +0800 Message-Id: <1702609653-45835-2-git-send-email-alibuda@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1702609653-45835-1-git-send-email-alibuda@linux.alibaba.com> References: <1702609653-45835-1-git-send-email-alibuda@linux.alibaba.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC From: "D. Wythe" To support the prog update, we need to ensure that the prog seen within the hook is always valid. Considering that hooks are always protected by rcu_read_lock(), which provide us the ability to access the prog under rcu. Signed-off-by: D. Wythe --- net/netfilter/nf_bpf_link.c | 68 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 53 insertions(+), 15 deletions(-) diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index e502ec0..e17f256 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -8,17 +8,8 @@ #include #include -static unsigned int nf_hook_run_bpf(void *bpf_prog, struct sk_buff *skb, - const struct nf_hook_state *s) -{ - const struct bpf_prog *prog = bpf_prog; - struct bpf_nf_ctx ctx = { - .state = s, - .skb = skb, - }; - - return bpf_prog_run(prog, &ctx); -} +/* protect link update in parallel */ +static DEFINE_MUTEX(bpf_nf_mutex); struct bpf_nf_link { struct bpf_link link; @@ -26,8 +17,22 @@ struct bpf_nf_link { struct net *net; u32 dead; const struct nf_defrag_hook *defrag_hook; + const struct bpf_prog __rcu *nf_prog; + struct rcu_head head; }; +static unsigned int nf_hook_run_bpf(void *bpf_link, struct sk_buff *skb, + const struct nf_hook_state *s) +{ + const struct bpf_nf_link *link = bpf_link; + struct bpf_nf_ctx ctx = { + .state = s, + .skb = skb, + }; + + return bpf_prog_run(rcu_dereference(link->nf_prog), &ctx); +} + #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) || IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) static const struct nf_defrag_hook * get_proto_defrag_hook(struct bpf_nf_link *link, @@ -126,8 +131,7 @@ static void bpf_nf_link_release(struct bpf_link *link) static void bpf_nf_link_dealloc(struct bpf_link *link) { struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); - - kfree(nf_link); + kfree_rcu(nf_link, head); } static int bpf_nf_link_detach(struct bpf_link *link) @@ -162,7 +166,35 @@ static int bpf_nf_link_fill_link_info(const struct bpf_link *link, static int bpf_nf_link_update(struct bpf_link *link, struct bpf_prog *new_prog, struct bpf_prog *old_prog) { - return -EOPNOTSUPP; + struct bpf_nf_link *nf_link = container_of(link, struct bpf_nf_link, link); + int err = 0; + + mutex_lock(&bpf_nf_mutex); + + if (nf_link->dead) { + err = -EPERM; + goto out; + } + + /* target old_prog mismatch */ + if (old_prog && link->prog != old_prog) { + err = -EPERM; + goto out; + } + + old_prog = link->prog; + if (old_prog == new_prog) { + /* don't need update */ + bpf_prog_put(new_prog); + goto out; + } + + rcu_assign_pointer(nf_link->nf_prog, new_prog); + old_prog = xchg(&link->prog, new_prog); + bpf_prog_put(old_prog); +out: + mutex_unlock(&bpf_nf_mutex); + return err; } static const struct bpf_link_ops bpf_nf_link_lops = { @@ -226,7 +258,13 @@ int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) link->hook_ops.hook = nf_hook_run_bpf; link->hook_ops.hook_ops_type = NF_HOOK_OP_BPF; - link->hook_ops.priv = prog; + + rcu_assign_pointer(link->nf_prog, prog); + + /* bpf_nf_link_release & bpf_nf_link_dealloc() can ensures that link remains + * valid at all times within nf_hook_run_bpf(). + */ + link->hook_ops.priv = link; link->hook_ops.pf = attr->link_create.netfilter.pf; link->hook_ops.priority = attr->link_create.netfilter.priority; From patchwork Fri Dec 15 03:07:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 13493967 X-Patchwork-Delegate: bpf@iogearbox.net Received: from out199-18.us.a.mail.aliyun.com (out199-18.us.a.mail.aliyun.com [47.90.199.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80B3663B3; Fri, 15 Dec 2023 03:08:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R931e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0VyWIqbq_1702609660; Received: from j66a10360.sqa.eu95.tbsite.net(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0VyWIqbq_1702609660) by smtp.aliyun-inc.com; Fri, 15 Dec 2023 11:07:41 +0800 From: "D. Wythe" To: pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, coreteam@netfilter.org, netfilter-devel@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ast@kernel.org Subject: [RFC nf-next v1 2/2] selftests/bpf: Add netfilter link prog update test Date: Fri, 15 Dec 2023 11:07:33 +0800 Message-Id: <1702609653-45835-3-git-send-email-alibuda@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1702609653-45835-1-git-send-email-alibuda@linux.alibaba.com> References: <1702609653-45835-1-git-send-email-alibuda@linux.alibaba.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC From: "D. Wythe" Update prog for active links and verify whether the prog has been successfully replaced. Expected output: ./test_progs -t netfilter_link_update_prog Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: D. Wythe --- .../bpf/prog_tests/netfilter_link_update_prog.c | 83 ++++++++++++++++++++++ .../bpf/progs/test_netfilter_link_update_prog.c | 24 +++++++ 2 files changed, 107 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/netfilter_link_update_prog.c create mode 100644 tools/testing/selftests/bpf/progs/test_netfilter_link_update_prog.c diff --git a/tools/testing/selftests/bpf/prog_tests/netfilter_link_update_prog.c b/tools/testing/selftests/bpf/prog_tests/netfilter_link_update_prog.c new file mode 100644 index 00000000..d23b544 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/netfilter_link_update_prog.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include +#include +#include +#include "test_netfilter_link_update_prog.skel.h" + +#define SERVER_ADDR "127.0.0.1" +#define SERVER_PORT 12345 + +static const char dummy_message[] = "A dummy message"; + +static int send_dummy(int client_fd) +{ + struct sockaddr_storage saddr; + struct sockaddr *saddr_p; + socklen_t saddr_len; + int err; + + saddr_p = (struct sockaddr *)&saddr; + err = make_sockaddr(AF_INET, SERVER_ADDR, SERVER_PORT, &saddr, &saddr_len); + if (!ASSERT_OK(err, "make_sockaddr")) + return -1; + + err = sendto(client_fd, dummy_message, sizeof(dummy_message) - 1, 0, saddr_p, saddr_len); + if (!ASSERT_GE(err, 0, "sendto")) + return -1; + + return 0; +} + +void test_netfilter_link_update_prog(void) +{ + LIBBPF_OPTS(bpf_netfilter_opts, opts, + .pf = NFPROTO_IPV4, + .hooknum = NF_INET_LOCAL_OUT, + .priority = 100); + struct test_netfilter_link_update_prog *skel; + struct bpf_program *prog; + int server_fd, client_fd; + int err; + + skel = test_netfilter_link_update_prog__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_netfilter_link_update_prog__open_and_load")) + goto out; + + prog = skel->progs.nf_link_prog; + + if (!ASSERT_OK_PTR(prog, "load program")) + goto out; + + skel->links.nf_link_prog = bpf_program__attach_netfilter(prog, &opts); + if (!ASSERT_OK_PTR(skel->links.nf_link_prog, "attach netfilter program")) + goto out; + + server_fd = start_server(AF_INET, SOCK_DGRAM, SERVER_ADDR, SERVER_PORT, 0); + if (!ASSERT_GE(server_fd, 0, "start_server")) + goto out; + + client_fd = connect_to_fd(server_fd, 0); + if (!ASSERT_GE(client_fd, 0, "connect_to_fd")) + goto out; + + send_dummy(client_fd); + + ASSERT_EQ(skel->bss->counter, 0, "counter should be zero"); + + err = bpf_link__update_program(skel->links.nf_link_prog, skel->progs.nf_link_prog_new); + if (!ASSERT_OK(err, "bpf_link__update_program")) + goto out; + + send_dummy(client_fd); + ASSERT_GE(skel->bss->counter, 0, "counter should be greater than zero"); +out: + if (client_fd > 0) + close(client_fd); + if (server_fd > 0) + close(server_fd); + + test_netfilter_link_update_prog__destroy(skel); +} + + diff --git a/tools/testing/selftests/bpf/progs/test_netfilter_link_update_prog.c b/tools/testing/selftests/bpf/progs/test_netfilter_link_update_prog.c new file mode 100644 index 00000000..42ae332 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_netfilter_link_update_prog.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include "vmlinux.h" +#include + +#define NF_ACCEPT 1 + +SEC("netfilter") +int nf_link_prog(struct bpf_nf_ctx *ctx) +{ + return NF_ACCEPT; +} + +u64 counter = 0; + +SEC("netfilter") +int nf_link_prog_new(struct bpf_nf_ctx *ctx) +{ + counter++; + return NF_ACCEPT; +} + +char _license[] SEC("license") = "GPL"; +