From 7a3f5b0de3647c854e34269c3332d7a1e902901a Mon Sep 17 00:00:00 2001 From: Ryoga Saito Date: Tue, 17 Aug 2021 08:39:37 +0000 Subject: [PATCH] netfilter: add netfilter hooks to SRv6 data plane This patch introduces netfilter hooks for solving the problem that conntrack couldn't record both inner flows and outer flows. This patch also introduces a new sysctl toggle for enabling lightweight tunnel netfilter hooks. Signed-off-by: Ryoga Saito Signed-off-by: Pablo Neira Ayuso --- .../networking/nf_conntrack-sysctl.rst | 7 ++ include/net/lwtunnel.h | 3 + include/net/netfilter/nf_hooks_lwtunnel.h | 7 ++ net/core/lwtunnel.c | 3 + net/ipv6/seg6_iptunnel.c | 75 +++++++++++- net/ipv6/seg6_local.c | 111 ++++++++++++------ net/netfilter/Makefile | 3 + net/netfilter/nf_conntrack_standalone.c | 15 +++ net/netfilter/nf_hooks_lwtunnel.c | 53 +++++++++ 9 files changed, 241 insertions(+), 36 deletions(-) create mode 100644 include/net/netfilter/nf_hooks_lwtunnel.h create mode 100644 net/netfilter/nf_hooks_lwtunnel.c diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst index 024d784157c8..34ca762ea56f 100644 --- a/Documentation/networking/nf_conntrack-sysctl.rst +++ b/Documentation/networking/nf_conntrack-sysctl.rst @@ -184,6 +184,13 @@ nf_conntrack_gre_timeout_stream - INTEGER (seconds) This extended timeout will be used in case there is an GRE stream detected. +nf_hooks_lwtunnel - BOOLEAN + - 0 - disabled (default) + - not 0 - enabled + + If this option is enabled, the lightweight tunnel netfilter hooks are + enabled. This option cannot be disabled once it is enabled. + nf_flowtable_tcp_timeout - INTEGER (seconds) default 30 diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index 05cfd6ff6528..6f15e6fa154e 100644 --- a/include/net/lwtunnel.h +++ b/include/net/lwtunnel.h @@ -51,6 +51,9 @@ struct lwtunnel_encap_ops { }; #ifdef CONFIG_LWTUNNEL + +DECLARE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled); + void lwtstate_free(struct lwtunnel_state *lws); static inline struct lwtunnel_state * diff --git a/include/net/netfilter/nf_hooks_lwtunnel.h b/include/net/netfilter/nf_hooks_lwtunnel.h new file mode 100644 index 000000000000..52e27920f829 --- /dev/null +++ b/include/net/netfilter/nf_hooks_lwtunnel.h @@ -0,0 +1,7 @@ +#include +#include + +#ifdef CONFIG_SYSCTL +int nf_hooks_lwtunnel_sysctl_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos); +#endif diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c index d0ae987d2de9..2820aca2173a 100644 --- a/net/core/lwtunnel.c +++ b/net/core/lwtunnel.c @@ -23,6 +23,9 @@ #include #include +DEFINE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled); +EXPORT_SYMBOL_GPL(nf_hooks_lwtunnel_enabled); + #ifdef CONFIG_MODULES static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index 897fa59c47de..6ebc7aa24466 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -26,6 +26,8 @@ #ifdef CONFIG_IPV6_SEG6_HMAC #include #endif +#include +#include static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo) { @@ -295,11 +297,19 @@ static int seg6_do_srh(struct sk_buff *skb) ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + nf_reset_ct(skb); return 0; } -static int seg6_input(struct sk_buff *skb) +static int seg6_input_finish(struct net *net, struct sock *sk, + struct sk_buff *skb) +{ + return dst_input(skb); +} + +static int seg6_input_core(struct net *net, struct sock *sk, + struct sk_buff *skb) { struct dst_entry *orig_dst = skb_dst(skb); struct dst_entry *dst = NULL; @@ -337,10 +347,41 @@ static int seg6_input(struct sk_buff *skb) if (unlikely(err)) return err; - return dst_input(skb); + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, + dev_net(skb->dev), NULL, skb, NULL, + skb_dst(skb)->dev, seg6_input_finish); + + return seg6_input_finish(dev_net(skb->dev), NULL, skb); } -static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) +static int seg6_input_nf(struct sk_buff *skb) +{ + struct net_device *dev = skb_dst(skb)->dev; + struct net *net = dev_net(skb->dev); + + switch (skb->protocol) { + case htons(ETH_P_IP): + return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, NULL, + skb, NULL, dev, seg6_input_core); + case htons(ETH_P_IPV6): + return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, NULL, + skb, NULL, dev, seg6_input_core); + } + + return -EINVAL; +} + +static int seg6_input(struct sk_buff *skb) +{ + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return seg6_input_nf(skb); + + return seg6_input_core(dev_net(skb->dev), NULL, skb); +} + +static int seg6_output_core(struct net *net, struct sock *sk, + struct sk_buff *skb) { struct dst_entry *orig_dst = skb_dst(skb); struct dst_entry *dst = NULL; @@ -387,12 +428,40 @@ static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) if (unlikely(err)) goto drop; + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb, + NULL, skb_dst(skb)->dev, dst_output); + return dst_output(net, sk, skb); drop: kfree_skb(skb); return err; } +static int seg6_output_nf(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct net_device *dev = skb_dst(skb)->dev; + + switch (skb->protocol) { + case htons(ETH_P_IP): + return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb, + NULL, dev, seg6_output_core); + case htons(ETH_P_IPV6): + return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb, + NULL, dev, seg6_output_core); + } + + return -EINVAL; +} + +static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return seg6_output_nf(net, sk, skb); + + return seg6_output_core(net, sk, skb); +} + static int seg6_build_state(struct net *net, struct nlattr *nla, unsigned int family, const void *cfg, struct lwtunnel_state **ts, diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c index 60bf3b877957..ddc8dfcd4e2b 100644 --- a/net/ipv6/seg6_local.c +++ b/net/ipv6/seg6_local.c @@ -30,6 +30,8 @@ #include #include #include +#include +#include #define SEG6_F_ATTR(i) BIT(i) @@ -413,12 +415,33 @@ drop: return -EINVAL; } +static int input_action_end_dx6_finish(struct net *net, struct sock *sk, + struct sk_buff *skb) +{ + struct dst_entry *orig_dst = skb_dst(skb); + struct in6_addr *nhaddr = NULL; + struct seg6_local_lwt *slwt; + + slwt = seg6_local_lwtunnel(orig_dst->lwtstate); + + /* The inner packet is not associated to any local interface, + * so we do not call netif_rx(). + * + * If slwt->nh6 is set to ::, then lookup the nexthop for the + * inner packet's DA. Otherwise, use the specified nexthop. + */ + if (!ipv6_addr_any(&slwt->nh6)) + nhaddr = &slwt->nh6; + + seg6_lookup_nexthop(skb, nhaddr, 0); + + return dst_input(skb); +} + /* decapsulate and forward to specified nexthop */ static int input_action_end_dx6(struct sk_buff *skb, struct seg6_local_lwt *slwt) { - struct in6_addr *nhaddr = NULL; - /* this function accepts IPv6 encapsulated packets, with either * an SRH with SL=0, or no SRH. */ @@ -429,40 +452,30 @@ static int input_action_end_dx6(struct sk_buff *skb, if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto drop; - /* The inner packet is not associated to any local interface, - * so we do not call netif_rx(). - * - * If slwt->nh6 is set to ::, then lookup the nexthop for the - * inner packet's DA. Otherwise, use the specified nexthop. - */ - - if (!ipv6_addr_any(&slwt->nh6)) - nhaddr = &slwt->nh6; - skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + nf_reset_ct(skb); - seg6_lookup_nexthop(skb, nhaddr, 0); + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, + dev_net(skb->dev), NULL, skb, NULL, + skb_dst(skb)->dev, input_action_end_dx6_finish); - return dst_input(skb); + return input_action_end_dx6_finish(dev_net(skb->dev), NULL, skb); drop: kfree_skb(skb); return -EINVAL; } -static int input_action_end_dx4(struct sk_buff *skb, - struct seg6_local_lwt *slwt) +static int input_action_end_dx4_finish(struct net *net, struct sock *sk, + struct sk_buff *skb) { + struct dst_entry *orig_dst = skb_dst(skb); + struct seg6_local_lwt *slwt; struct iphdr *iph; __be32 nhaddr; int err; - if (!decap_and_validate(skb, IPPROTO_IPIP)) - goto drop; - - if (!pskb_may_pull(skb, sizeof(struct iphdr))) - goto drop; - - skb->protocol = htons(ETH_P_IP); + slwt = seg6_local_lwtunnel(orig_dst->lwtstate); iph = ip_hdr(skb); @@ -470,14 +483,34 @@ static int input_action_end_dx4(struct sk_buff *skb, skb_dst_drop(skb); - skb_set_transport_header(skb, sizeof(struct iphdr)); - err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev); - if (err) - goto drop; + if (err) { + kfree_skb(skb); + return -EINVAL; + } return dst_input(skb); +} +static int input_action_end_dx4(struct sk_buff *skb, + struct seg6_local_lwt *slwt) +{ + if (!decap_and_validate(skb, IPPROTO_IPIP)) + goto drop; + + if (!pskb_may_pull(skb, sizeof(struct iphdr))) + goto drop; + + skb->protocol = htons(ETH_P_IP); + skb_set_transport_header(skb, sizeof(struct iphdr)); + nf_reset_ct(skb); + + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, + dev_net(skb->dev), NULL, skb, NULL, + skb_dst(skb)->dev, input_action_end_dx4_finish); + + return input_action_end_dx4_finish(dev_net(skb->dev), NULL, skb); drop: kfree_skb(skb); return -EINVAL; @@ -645,6 +678,7 @@ static struct sk_buff *end_dt_vrf_core(struct sk_buff *skb, skb_dst_drop(skb); skb_set_transport_header(skb, hdrlen); + nf_reset_ct(skb); return end_dt_vrf_rcv(skb, family, vrf); @@ -1078,7 +1112,8 @@ static void seg6_local_update_counters(struct seg6_local_lwt *slwt, u64_stats_update_end(&pcounters->syncp); } -static int seg6_local_input(struct sk_buff *skb) +static int seg6_local_input_core(struct net *net, struct sock *sk, + struct sk_buff *skb) { struct dst_entry *orig_dst = skb_dst(skb); struct seg6_action_desc *desc; @@ -1086,11 +1121,6 @@ static int seg6_local_input(struct sk_buff *skb) unsigned int len = skb->len; int rc; - if (skb->protocol != htons(ETH_P_IPV6)) { - kfree_skb(skb); - return -EINVAL; - } - slwt = seg6_local_lwtunnel(orig_dst->lwtstate); desc = slwt->desc; @@ -1104,6 +1134,21 @@ static int seg6_local_input(struct sk_buff *skb) return rc; } +static int seg6_local_input(struct sk_buff *skb) +{ + if (skb->protocol != htons(ETH_P_IPV6)) { + kfree_skb(skb); + return -EINVAL; + } + + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, + dev_net(skb->dev), NULL, skb, skb->dev, NULL, + seg6_local_input_core); + + return seg6_local_input_core(dev_net(skb->dev), NULL, skb); +} + static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = { [SEG6_LOCAL_ACTION] = { .type = NLA_U32 }, [SEG6_LOCAL_SRH] = { .type = NLA_BINARY }, diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 049890e00a3d..aab20e575ecd 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -212,3 +212,6 @@ obj-$(CONFIG_IP_SET) += ipset/ # IPVS obj-$(CONFIG_IP_VS) += ipvs/ + +# lwtunnel +obj-$(CONFIG_LWTUNNEL) += nf_hooks_lwtunnel.o diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index e84b499b7bfa..7e0d956da51d 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -22,6 +22,9 @@ #include #include #include +#ifdef CONFIG_LWTUNNEL +#include +#endif #include static bool enable_hooks __read_mostly; @@ -612,6 +615,9 @@ enum nf_ct_sysctl_index { NF_SYSCTL_CT_PROTO_TIMEOUT_GRE, NF_SYSCTL_CT_PROTO_TIMEOUT_GRE_STREAM, #endif +#ifdef CONFIG_LWTUNNEL + NF_SYSCTL_CT_LWTUNNEL, +#endif __NF_SYSCTL_CT_LAST_SYSCTL, }; @@ -958,6 +964,15 @@ static struct ctl_table nf_ct_sysctl_table[] = { .mode = 0644, .proc_handler = proc_dointvec_jiffies, }, +#endif +#ifdef CONFIG_LWTUNNEL + [NF_SYSCTL_CT_LWTUNNEL] = { + .procname = "nf_hooks_lwtunnel", + .data = NULL, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = nf_hooks_lwtunnel_sysctl_handler, + }, #endif {} }; diff --git a/net/netfilter/nf_hooks_lwtunnel.c b/net/netfilter/nf_hooks_lwtunnel.c new file mode 100644 index 000000000000..00e89ffd78f6 --- /dev/null +++ b/net/netfilter/nf_hooks_lwtunnel.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include + +static inline int nf_hooks_lwtunnel_get(void) +{ + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) + return 1; + else + return 0; +} + +static inline int nf_hooks_lwtunnel_set(int enable) +{ + if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) { + if (!enable) + return -EBUSY; + } else if (enable) { + static_branch_enable(&nf_hooks_lwtunnel_enabled); + } + + return 0; +} + +#ifdef CONFIG_SYSCTL +int nf_hooks_lwtunnel_sysctl_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int proc_nf_hooks_lwtunnel_enabled = 0; + struct ctl_table tmp = { + .procname = table->procname, + .data = &proc_nf_hooks_lwtunnel_enabled, + .maxlen = sizeof(int), + .mode = table->mode, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }; + int ret; + + if (!write) + proc_nf_hooks_lwtunnel_enabled = nf_hooks_lwtunnel_get(); + + ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); + + if (write && ret == 0) + ret = nf_hooks_lwtunnel_set(proc_nf_hooks_lwtunnel_enabled); + + return ret; +} +EXPORT_SYMBOL_GPL(nf_hooks_lwtunnel_sysctl_handler); +#endif /* CONFIG_SYSCTL */