From 971502d77faa50a37c89bc6d172450294ad9a5fd Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 11 Apr 2019 16:36:41 +0200 Subject: [PATCH] bridge: netfilter: unroll NF_HOOK helper in bridge input path Replace NF_HOOK() based invocation of the netfilter hooks with a private copy of nf_hook_slow(). This copy has one difference: it can return the rx handler value expected by the stack, i.e. RX_HANDLER_CONSUMED or RX_HANDLER_PASS. This is needed by the next patch to invoke the ebtables "broute" table via the standard netfilter hooks rather than the custom "br_should_route_hook" indirection that is used now. When the skb is to be "brouted", we must return RX_HANDLER_PASS from the bridge rx input handler, but there is no way to indicate this via NF_HOOK(), unless perhaps by some hack such as exposing bridge_cb in the netfilter core or a percpu flag. text data bss dec filename 3369 56 0 3425 net/bridge/br_input.o.before 3458 40 0 3498 net/bridge/br_input.o.after This allows removal of the "br_should_route_hook" in the next patch. Signed-off-by: Florian Westphal Acked-by: David S. Miller Acked-by: Nikolay Aleksandrov Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_queue.h | 3 ++ net/bridge/br_input.c | 55 +++++++++++++++++++++++++++++--- net/netfilter/core.c | 1 + net/netfilter/nf_internals.h | 3 -- net/netfilter/nf_queue.c | 1 + 5 files changed, 56 insertions(+), 7 deletions(-) diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h index a50a69f5334c..7239105d9d2e 100644 --- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -119,4 +119,7 @@ nfqueue_hash(const struct sk_buff *skb, u16 queue, u16 queues_total, u8 family, return queue; } +int nf_queue(struct sk_buff *skb, struct nf_hook_state *state, + const struct nf_hook_entries *entries, unsigned int index, + unsigned int verdict); #endif /* _NF_QUEUE_H */ diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index e2f93e5c72da..4ac34fb5f943 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -206,6 +207,55 @@ static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_bu return 0; } +static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb) +{ +#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE + struct nf_hook_entries *e = NULL; + struct nf_hook_state state; + unsigned int verdict, i; + struct net *net; + int ret; + + net = dev_net(skb->dev); +#ifdef HAVE_JUMP_LABEL + if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING])) + goto frame_finish; +#endif + + e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]); + if (!e) + goto frame_finish; + + nf_hook_state_init(&state, NF_BR_PRE_ROUTING, + NFPROTO_BRIDGE, skb->dev, NULL, NULL, + net, br_handle_frame_finish); + + for (i = 0; i < e->num_hook_entries; i++) { + verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state); + switch (verdict & NF_VERDICT_MASK) { + case NF_ACCEPT: + break; + case NF_DROP: + kfree_skb(skb); + return RX_HANDLER_CONSUMED; + case NF_QUEUE: + ret = nf_queue(skb, &state, e, i, verdict); + if (ret == 1) + continue; + return RX_HANDLER_CONSUMED; + default: /* STOLEN */ + return RX_HANDLER_CONSUMED; + } + } +frame_finish: + net = dev_net(skb->dev); + br_handle_frame_finish(net, NULL, skb); +#else + br_handle_frame_finish(dev_net(skb->dev), NULL, skb); +#endif + return RX_HANDLER_CONSUMED; +} + /* * Return NULL if skb is handled * note: already called with rcu_read_lock @@ -304,10 +354,7 @@ forward: if (ether_addr_equal(p->br->dev->dev_addr, dest)) skb->pkt_type = PACKET_HOST; - NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, - dev_net(skb->dev), NULL, skb, skb->dev, NULL, - br_handle_frame_finish); - break; + return nf_hook_bridge_pre(skb, pskb); default: drop: kfree_skb(skb); diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 93aaec3a54ec..71f06900473e 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include "nf_internals.h" diff --git a/net/netfilter/nf_internals.h b/net/netfilter/nf_internals.h index e15779fd58e3..d6c43902ebd7 100644 --- a/net/netfilter/nf_internals.h +++ b/net/netfilter/nf_internals.h @@ -7,9 +7,6 @@ #include /* nf_queue.c */ -int nf_queue(struct sk_buff *skb, struct nf_hook_state *state, - const struct nf_hook_entries *entries, unsigned int index, - unsigned int verdict); void nf_queue_nf_hook_drop(struct net *net); /* nf_log.c */ diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index a36a77bae1d6..9dc1d6e04946 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -240,6 +240,7 @@ int nf_queue(struct sk_buff *skb, struct nf_hook_state *state, return 0; } +EXPORT_SYMBOL_GPL(nf_queue); static unsigned int nf_iterate(struct sk_buff *skb, struct nf_hook_state *state,