From patchwork Thu Nov 5 10:41:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: wenxu X-Patchwork-Id: 11883899 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7B61C00A89 for ; Thu, 5 Nov 2020 10:42:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6194E206E3 for ; Thu, 5 Nov 2020 10:42:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729827AbgKEKmC (ORCPT ); Thu, 5 Nov 2020 05:42:02 -0500 Received: from m9785.mail.qiye.163.com ([220.181.97.85]:27078 "EHLO m9785.mail.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729263AbgKEKmC (ORCPT ); Thu, 5 Nov 2020 05:42:02 -0500 Received: from localhost.localdomain (unknown [123.59.132.129]) by m9785.mail.qiye.163.com (Hmail) with ESMTPA id 411025C1CBA; Thu, 5 Nov 2020 18:41:34 +0800 (CST) From: wenxu@ucloud.cn To: kuba@kernel.org, marcelo.leitner@gmail.com Cc: netdev@vger.kernel.org Subject: [PATCH v3 net-next 2/2] net/sched: act_frag: add implict packet fragment support. Date: Thu, 5 Nov 2020 18:41:33 +0800 Message-Id: <1604572893-16156-2-git-send-email-wenxu@ucloud.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1604572893-16156-1-git-send-email-wenxu@ucloud.cn> References: <1604572893-16156-1-git-send-email-wenxu@ucloud.cn> X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgYFAkeWUFZS1VLWVdZKFlBSUI3V1ktWUFJV1kPCR oVCBIfWUFZHkhLTk0fGk8YSUwdVkpNS09OTElDQk9IT09VGRETFhoSFyQUDg9ZV1kWGg8SFR0UWU FZT0tIVUpKS0hOT1VLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6N0k6STo5Mz08HDoWLjYSSA8V H0sKFEtVSlVKTUtPTkxJQ0JPTk5NVTMWGhIXVQweFQMOOw4YFxQOH1UYFUVZV1kSC1lBWUpJSFVO QlVKSElVSklCWVdZCAFZQUpKTUpMNwY+ X-HM-Tid: 0a7597ff54482087kuqy411025c1cba Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: wenxu Currently kernel tc subsystem can do conntrack in act_ct. But when several fragment packets go through the act_ct, function tcf_ct_handle_fragments will defrag the packets to a big one. But the last action will redirect mirred to a device which maybe lead the reassembly big packet over the mtu of target device. This patch add support for a xmit hook to mirred, that gets executed before xmiting the packet. Then, when act_ct gets loaded, it configs that hook. The frag xmit hook maybe reused by other modules. Signed-off-by: wenxu --- v2: Fix the crash for act_frag module without load v3: modify the kconfig describe and put tcf_xmit_hook_is_enabled in the tcf_dev_queue_xmit, and xchg atomic for tcf_xmit_hook include/net/act_api.h | 17 ++++++ net/sched/Kconfig | 13 ++++ net/sched/Makefile | 1 + net/sched/act_api.c | 51 ++++++++++++++++ net/sched/act_ct.c | 7 +++ net/sched/act_frag.c | 162 +++++++++++++++++++++++++++++++++++++++++++++++++ net/sched/act_mirred.c | 2 +- 7 files changed, 252 insertions(+), 1 deletion(-) create mode 100644 net/sched/act_frag.c diff --git a/include/net/act_api.h b/include/net/act_api.h index 8721492..8b82675 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -239,6 +239,23 @@ int tcf_action_check_ctrlact(int action, struct tcf_proto *tp, struct netlink_ext_ack *newchain); struct tcf_chain *tcf_action_set_ctrlact(struct tc_action *a, int action, struct tcf_chain *newchain); + +int tcf_dev_queue_xmit(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb)); +int tcf_set_xmit_hook(int (*xmit_hook)(struct sk_buff *skb, + int (*xmit)(struct sk_buff *skb))); +void tcf_clear_xmit_hook(void); + +#if IS_ENABLED(CONFIG_NET_ACT_FRAG) +int tcf_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb)); +#else +static inline int tcf_frag_xmit_hook(struct sk_buff *skb, + int (*xmit)(struct sk_buff *skb)) +{ + return 0; +} +#endif + + #endif /* CONFIG_NET_CLS_ACT */ static inline void tcf_action_stats_update(struct tc_action *a, u64 bytes, diff --git a/net/sched/Kconfig b/net/sched/Kconfig index a3b37d8..9a240c7 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -974,9 +974,22 @@ config NET_ACT_TUNNEL_KEY To compile this code as a module, choose M here: the module will be called act_tunnel_key. +config NET_ACT_FRAG + tristate "Packet fragmentation" + depends on NET_CLS_ACT + help + Say Y here to allow fragmenting big packets when outputting + with the mirred action. + + If unsure, say N. + + To compile this code as a module, choose M here: the + module will be called act_frag. + config NET_ACT_CT tristate "connection tracking tc action" depends on NET_CLS_ACT && NF_CONNTRACK && NF_NAT && NF_FLOW_TABLE + depends on NET_ACT_FRAG help Say Y here to allow sending the packets to conntrack module. diff --git a/net/sched/Makefile b/net/sched/Makefile index 66bbf9a..c146186 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_NET_IFE_SKBMARK) += act_meta_mark.o obj-$(CONFIG_NET_IFE_SKBPRIO) += act_meta_skbprio.o obj-$(CONFIG_NET_IFE_SKBTCINDEX) += act_meta_skbtcindex.o obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o +obj-$(CONFIG_NET_ACT_FRAG) += act_frag.o obj-$(CONFIG_NET_ACT_CT) += act_ct.o obj-$(CONFIG_NET_ACT_GATE) += act_gate.o obj-$(CONFIG_NET_SCH_FIFO) += sch_fifo.o diff --git a/net/sched/act_api.c b/net/sched/act_api.c index f66417d..e7b501c 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -22,6 +22,57 @@ #include #include +static int (*tcf_xmit_hook)(struct sk_buff *skb, + int (*xmit)(struct sk_buff *skb)); +static DEFINE_STATIC_KEY_FALSE(tcf_xmit_hook_in_use); + +static void tcf_inc_xmit_hook(void) +{ + static_branch_inc(&tcf_xmit_hook_in_use); +} + +static void tcf_dec_xmit_hook(void) +{ + static_branch_dec(&tcf_xmit_hook_in_use); +} + +static bool tcf_xmit_hook_enabled(void) +{ + return static_branch_unlikely(&tcf_xmit_hook_in_use); +} + +int tcf_set_xmit_hook(int (*xmit_hook)(struct sk_buff *skb, + int (*xmit)(struct sk_buff *skb))) +{ + if (!tcf_xmit_hook_enabled()) + xchg(&tcf_xmit_hook, xmit_hook); + else if (xmit_hook != tcf_xmit_hook) + return -EBUSY; + + tcf_inc_xmit_hook(); + + return 0; +} +EXPORT_SYMBOL_GPL(tcf_set_xmit_hook); + +void tcf_clear_xmit_hook(void) +{ + tcf_dec_xmit_hook(); + + if (!tcf_xmit_hook_enabled()) + xchg(&tcf_xmit_hook, NULL); +} +EXPORT_SYMBOL_GPL(tcf_clear_xmit_hook); + +int tcf_dev_queue_xmit(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb)) +{ + if (tcf_xmit_hook_enabled()) + return tcf_xmit_hook(skb, xmit); + else + return xmit(skb); +} +EXPORT_SYMBOL_GPL(tcf_dev_queue_xmit); + static void tcf_action_goto_chain_exec(const struct tc_action *a, struct tcf_result *res) { diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index aba3cd8..c45984a 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -1541,8 +1541,14 @@ static int __init ct_init_module(void) if (err) goto err_register; + err = tcf_set_xmit_hook(tcf_frag_xmit_hook); + if (err) + goto err_action; + return 0; +err_action: + tcf_unregister_action(&act_ct_ops, &ct_net_ops); err_register: tcf_ct_flow_tables_uninit(); err_tbl_init: @@ -1552,6 +1558,7 @@ static int __init ct_init_module(void) static void __exit ct_cleanup_module(void) { + tcf_clear_xmit_hook(); tcf_unregister_action(&act_ct_ops, &ct_net_ops); tcf_ct_flow_tables_uninit(); destroy_workqueue(act_ct_wq); diff --git a/net/sched/act_frag.c b/net/sched/act_frag.c new file mode 100644 index 0000000..71b9eb8 --- /dev/null +++ b/net/sched/act_frag.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +#include +#include +#include +#include +#include + +struct tcf_frag_data { + unsigned long dst; + struct qdisc_skb_cb cb; + __be16 inner_protocol; + u16 vlan_tci; + __be16 vlan_proto; + unsigned int l2_len; + u8 l2_data[VLAN_ETH_HLEN]; + int (*xmit)(struct sk_buff *skb); +}; + +static DEFINE_PER_CPU(struct tcf_frag_data, tcf_frag_data_storage); + +static int tcf_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct tcf_frag_data *data = this_cpu_ptr(&tcf_frag_data_storage); + + if (skb_cow_head(skb, data->l2_len) < 0) { + kfree_skb(skb); + return -ENOMEM; + } + + __skb_dst_copy(skb, data->dst); + *qdisc_skb_cb(skb) = data->cb; + skb->inner_protocol = data->inner_protocol; + if (data->vlan_tci & VLAN_CFI_MASK) + __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci & ~VLAN_CFI_MASK); + else + __vlan_hwaccel_clear_tag(skb); + + /* Reconstruct the MAC header. */ + skb_push(skb, data->l2_len); + memcpy(skb->data, &data->l2_data, data->l2_len); + skb_postpush_rcsum(skb, skb->data, data->l2_len); + skb_reset_mac_header(skb); + + data->xmit(skb); + + return 0; +} + +static void tcf_frag_prepare_frag(struct sk_buff *skb, + int (*xmit)(struct sk_buff *skb)) +{ + unsigned int hlen = skb_network_offset(skb); + struct tcf_frag_data *data; + + data = this_cpu_ptr(&tcf_frag_data_storage); + data->dst = skb->_skb_refdst; + data->cb = *qdisc_skb_cb(skb); + data->xmit = xmit; + data->inner_protocol = skb->inner_protocol; + if (skb_vlan_tag_present(skb)) + data->vlan_tci = skb_vlan_tag_get(skb) | VLAN_CFI_MASK; + else + data->vlan_tci = 0; + data->vlan_proto = skb->vlan_proto; + data->l2_len = hlen; + memcpy(&data->l2_data, skb->data, hlen); + + memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); + skb_pull(skb, hlen); +} + +static unsigned int +tcf_frag_dst_get_mtu(const struct dst_entry *dst) +{ + return dst->dev->mtu; +} + +static struct dst_ops tcf_frag_dst_ops = { + .family = AF_UNSPEC, + .mtu = tcf_frag_dst_get_mtu, +}; + +static int tcf_fragment(struct net *net, struct sk_buff *skb, + u16 mru, int (*xmit)(struct sk_buff *skb)) +{ + if (skb_network_offset(skb) > VLAN_ETH_HLEN) { + net_warn_ratelimited("L2 header too long to fragment\n"); + goto err; + } + + if (skb->protocol == htons(ETH_P_IP)) { + struct dst_entry tcf_frag_dst; + unsigned long orig_dst; + + tcf_frag_prepare_frag(skb, xmit); + dst_init(&tcf_frag_dst, &tcf_frag_dst_ops, NULL, 1, + DST_OBSOLETE_NONE, DST_NOCOUNT); + tcf_frag_dst.dev = skb->dev; + + orig_dst = skb->_skb_refdst; + skb_dst_set_noref(skb, &tcf_frag_dst); + IPCB(skb)->frag_max_size = mru; + + ip_do_fragment(net, skb->sk, skb, tcf_frag_xmit); + refdst_drop(orig_dst); + } else if (skb->protocol == htons(ETH_P_IPV6)) { + unsigned long orig_dst; + struct rt6_info tcf_frag_rt; + + tcf_frag_prepare_frag(skb, xmit); + memset(&tcf_frag_rt, 0, sizeof(tcf_frag_rt)); + dst_init(&tcf_frag_rt.dst, &tcf_frag_dst_ops, NULL, 1, + DST_OBSOLETE_NONE, DST_NOCOUNT); + tcf_frag_rt.dst.dev = skb->dev; + + orig_dst = skb->_skb_refdst; + skb_dst_set_noref(skb, &tcf_frag_rt.dst); + IP6CB(skb)->frag_max_size = mru; + + ipv6_stub->ipv6_fragment(net, skb->sk, skb, tcf_frag_xmit); + refdst_drop(orig_dst); + } else { + net_warn_ratelimited("Failed fragment ->%s: eth=%04x, MRU=%d, MTU=%d.\n", + netdev_name(skb->dev), ntohs(skb->protocol), + mru, skb->dev->mtu); + goto err; + } + + qdisc_skb_cb(skb)->mru = 0; + return 0; +err: + kfree_skb(skb); + return -1; +} + +int tcf_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb)) +{ + u16 mru = qdisc_skb_cb(skb)->mru; + int err; + + if (mru && skb->len > mru + skb->dev->hard_header_len) + err = tcf_fragment(dev_net(skb->dev), skb, mru, xmit); + else + err = xmit(skb); + + return err; +} +EXPORT_SYMBOL_GPL(tcf_frag_xmit_hook); + +static int __init frag_init_module(void) +{ + return 0; +} + +static void __exit frag_cleanup_module(void) +{ +} + +module_init(frag_init_module); +module_exit(frag_cleanup_module); +MODULE_AUTHOR("wenxu "); +MODULE_LICENSE("GPL v2"); diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 17d0095..7153c67 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -210,7 +210,7 @@ static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) int err; if (!want_ingress) - err = dev_queue_xmit(skb); + err = tcf_dev_queue_xmit(skb, dev_queue_xmit); else err = netif_receive_skb(skb);