From 29744a10c59ede4f996c0c893127ac11bcc85c0c Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:54 +0100 Subject: [PATCH 1/7] net: flow_offload: provision conntrack info in ct_metadata In order to offload connections in other states besides "established" the driver offload callbacks need to have access to connection conntrack info. Flow offload intermediate representation data structure already contains that data encoded in 'cookie' field, so just reuse it in the drivers. Reject offloading IP_CT_NEW connections for now by returning an error in relevant driver callbacks based on value of ctinfo. Support for offloading such connections will need to be added to the drivers afterwards. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- .../ethernet/mellanox/mlx5/core/en/tc_ct.c | 4 ++++ .../ethernet/netronome/nfp/flower/conntrack.c | 24 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c index 313df8232db7..193562c14c44 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c @@ -1073,12 +1073,16 @@ mlx5_tc_ct_block_flow_offload_add(struct mlx5_ct_ft *ft, struct mlx5_tc_ct_priv *ct_priv = ft->ct_priv; struct flow_action_entry *meta_action; unsigned long cookie = flow->cookie; + enum ip_conntrack_info ctinfo; struct mlx5_ct_entry *entry; int err; meta_action = mlx5_tc_ct_get_ct_metadata_action(flow_rule); if (!meta_action) return -EOPNOTSUPP; + ctinfo = meta_action->ct_metadata.cookie & NFCT_INFOMASK; + if (ctinfo == IP_CT_NEW) + return -EOPNOTSUPP; spin_lock_bh(&ct_priv->ht_lock); entry = rhashtable_lookup_fast(&ft->ct_entries_ht, &cookie, cts_ht_params); diff --git a/drivers/net/ethernet/netronome/nfp/flower/conntrack.c b/drivers/net/ethernet/netronome/nfp/flower/conntrack.c index f693119541d5..d23830b5bcb8 100644 --- a/drivers/net/ethernet/netronome/nfp/flower/conntrack.c +++ b/drivers/net/ethernet/netronome/nfp/flower/conntrack.c @@ -1964,6 +1964,27 @@ int nfp_fl_ct_stats(struct flow_cls_offload *flow, return 0; } +static bool +nfp_fl_ct_offload_nft_supported(struct flow_cls_offload *flow) +{ + struct flow_rule *flow_rule = flow->rule; + struct flow_action *flow_action = + &flow_rule->action; + struct flow_action_entry *act; + int i; + + flow_action_for_each(i, act, flow_action) { + if (act->id == FLOW_ACTION_CT_METADATA) { + enum ip_conntrack_info ctinfo = + act->ct_metadata.cookie & NFCT_INFOMASK; + + return ctinfo != IP_CT_NEW; + } + } + + return false; +} + static int nfp_fl_ct_offload_nft_flow(struct nfp_fl_ct_zone_entry *zt, struct flow_cls_offload *flow) { @@ -1976,6 +1997,9 @@ nfp_fl_ct_offload_nft_flow(struct nfp_fl_ct_zone_entry *zt, struct flow_cls_offl extack = flow->common.extack; switch (flow->command) { case FLOW_CLS_REPLACE: + if (!nfp_fl_ct_offload_nft_supported(flow)) + return -EOPNOTSUPP; + /* Netfilter can request offload multiple times for the same * flow - protect against adding duplicates. */ From 0eb5acb16418898c3d813e2c2d59a7ea7763a824 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:55 +0100 Subject: [PATCH 2/7] netfilter: flowtable: fixup UDP timeout depending on ct state Currently flow_offload_fixup_ct() function assumes that only replied UDP connections can be offloaded and hardcodes UDP_CT_REPLIED timeout value. To enable UDP NEW connection offload in following patches extract the actual connections state from ct->status and set the timeout according to it. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/netfilter/nf_flow_table_core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 81c26a96c30b..04bd0ed4d2ae 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -193,8 +193,11 @@ static void flow_offload_fixup_ct(struct nf_conn *ct) timeout -= tn->offload_timeout; } else if (l4num == IPPROTO_UDP) { struct nf_udp_net *tn = nf_udp_pernet(net); + enum udp_conntrack state = + test_bit(IPS_SEEN_REPLY_BIT, &ct->status) ? + UDP_CT_REPLIED : UDP_CT_UNREPLIED; - timeout = tn->timeouts[UDP_CT_REPLIED]; + timeout = tn->timeouts[state]; timeout -= tn->offload_timeout; } else { return; From 8f84780b84d645d6e35467f4a6f3236b20d7f4b2 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:56 +0100 Subject: [PATCH 3/7] netfilter: flowtable: allow unidirectional rules Modify flow table offload to support unidirectional connections by extending enum nf_flow_flags with new "NF_FLOW_HW_BIDIRECTIONAL" flag. Only offload reply direction when the flag is set. This infrastructure change is necessary to support offloading UDP NEW connections in original direction in following patches in series. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- include/net/netfilter/nf_flow_table.h | 1 + net/netfilter/nf_flow_table_offload.c | 12 ++++++++---- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h index cd982f4a0f50..88ab98ab41d9 100644 --- a/include/net/netfilter/nf_flow_table.h +++ b/include/net/netfilter/nf_flow_table.h @@ -164,6 +164,7 @@ enum nf_flow_flags { NF_FLOW_HW_DYING, NF_FLOW_HW_DEAD, NF_FLOW_HW_PENDING, + NF_FLOW_HW_BIDIRECTIONAL, }; enum flow_offload_type { diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 4d9b99abe37d..8b852f10fab4 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -895,8 +895,9 @@ static int flow_offload_rule_add(struct flow_offload_work *offload, ok_count += flow_offload_tuple_add(offload, flow_rule[0], FLOW_OFFLOAD_DIR_ORIGINAL); - ok_count += flow_offload_tuple_add(offload, flow_rule[1], - FLOW_OFFLOAD_DIR_REPLY); + if (test_bit(NF_FLOW_HW_BIDIRECTIONAL, &offload->flow->flags)) + ok_count += flow_offload_tuple_add(offload, flow_rule[1], + FLOW_OFFLOAD_DIR_REPLY); if (ok_count == 0) return -ENOENT; @@ -926,7 +927,8 @@ static void flow_offload_work_del(struct flow_offload_work *offload) { clear_bit(IPS_HW_OFFLOAD_BIT, &offload->flow->ct->status); flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_ORIGINAL); - flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY); + if (test_bit(NF_FLOW_HW_BIDIRECTIONAL, &offload->flow->flags)) + flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY); set_bit(NF_FLOW_HW_DEAD, &offload->flow->flags); } @@ -946,7 +948,9 @@ static void flow_offload_work_stats(struct flow_offload_work *offload) u64 lastused; flow_offload_tuple_stats(offload, FLOW_OFFLOAD_DIR_ORIGINAL, &stats[0]); - flow_offload_tuple_stats(offload, FLOW_OFFLOAD_DIR_REPLY, &stats[1]); + if (test_bit(NF_FLOW_HW_BIDIRECTIONAL, &offload->flow->flags)) + flow_offload_tuple_stats(offload, FLOW_OFFLOAD_DIR_REPLY, + &stats[1]); lastused = max_t(u64, stats[0].lastused, stats[1].lastused); offload->flow->timeout = max_t(u64, offload->flow->timeout, From 1a441a9b8be8849957a01413a144f84932c324cb Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:57 +0100 Subject: [PATCH 4/7] netfilter: flowtable: cache info of last offload Modify flow table offload to cache the last ct info status that was passed to the driver offload callbacks by extending enum nf_flow_flags with new "NF_FLOW_HW_ESTABLISHED" flag. Set the flag if ctinfo was 'established' during last act_ct meta actions fill call. This infrastructure change is necessary to optimize promoting of UDP connections from 'new' to 'established' in following patches in this series. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- include/net/netfilter/nf_flow_table.h | 7 ++++--- net/netfilter/nf_flow_table_inet.c | 2 +- net/netfilter/nf_flow_table_offload.c | 6 +++--- net/sched/act_ct.c | 12 +++++++----- 4 files changed, 15 insertions(+), 12 deletions(-) diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h index 88ab98ab41d9..ebb28ec5b6fa 100644 --- a/include/net/netfilter/nf_flow_table.h +++ b/include/net/netfilter/nf_flow_table.h @@ -57,7 +57,7 @@ struct nf_flowtable_type { struct net_device *dev, enum flow_block_command cmd); int (*action)(struct net *net, - const struct flow_offload *flow, + struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule); void (*free)(struct nf_flowtable *ft); @@ -165,6 +165,7 @@ enum nf_flow_flags { NF_FLOW_HW_DEAD, NF_FLOW_HW_PENDING, NF_FLOW_HW_BIDIRECTIONAL, + NF_FLOW_HW_ESTABLISHED, }; enum flow_offload_type { @@ -313,10 +314,10 @@ void nf_flow_table_offload_flush_cleanup(struct nf_flowtable *flowtable); int nf_flow_table_offload_setup(struct nf_flowtable *flowtable, struct net_device *dev, enum flow_block_command cmd); -int nf_flow_rule_route_ipv4(struct net *net, const struct flow_offload *flow, +int nf_flow_rule_route_ipv4(struct net *net, struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule); -int nf_flow_rule_route_ipv6(struct net *net, const struct flow_offload *flow, +int nf_flow_rule_route_ipv6(struct net *net, struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule); diff --git a/net/netfilter/nf_flow_table_inet.c b/net/netfilter/nf_flow_table_inet.c index 0ccabf3fa6aa..9505f9d188ff 100644 --- a/net/netfilter/nf_flow_table_inet.c +++ b/net/netfilter/nf_flow_table_inet.c @@ -39,7 +39,7 @@ nf_flow_offload_inet_hook(void *priv, struct sk_buff *skb, } static int nf_flow_rule_route_inet(struct net *net, - const struct flow_offload *flow, + struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule) { diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 8b852f10fab4..1c26f03fc661 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -679,7 +679,7 @@ nf_flow_rule_route_common(struct net *net, const struct flow_offload *flow, return 0; } -int nf_flow_rule_route_ipv4(struct net *net, const struct flow_offload *flow, +int nf_flow_rule_route_ipv4(struct net *net, struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule) { @@ -704,7 +704,7 @@ int nf_flow_rule_route_ipv4(struct net *net, const struct flow_offload *flow, } EXPORT_SYMBOL_GPL(nf_flow_rule_route_ipv4); -int nf_flow_rule_route_ipv6(struct net *net, const struct flow_offload *flow, +int nf_flow_rule_route_ipv6(struct net *net, struct flow_offload *flow, enum flow_offload_tuple_dir dir, struct nf_flow_rule *flow_rule) { @@ -735,7 +735,7 @@ nf_flow_offload_rule_alloc(struct net *net, { const struct nf_flowtable *flowtable = offload->flowtable; const struct flow_offload_tuple *tuple, *other_tuple; - const struct flow_offload *flow = offload->flow; + struct flow_offload *flow = offload->flow; struct dst_entry *other_dst = NULL; struct nf_flow_rule *flow_rule; int err = -ENOMEM; diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index d68bb5dbf0dc..b9d3e338f72d 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -170,11 +170,11 @@ tcf_ct_flow_table_add_action_nat_udp(const struct nf_conntrack_tuple *tuple, static void tcf_ct_flow_table_add_action_meta(struct nf_conn *ct, enum ip_conntrack_dir dir, + enum ip_conntrack_info ctinfo, struct flow_action *action) { struct nf_conn_labels *ct_labels; struct flow_action_entry *entry; - enum ip_conntrack_info ctinfo; u32 *act_ct_labels; entry = tcf_ct_flow_table_flow_action_get_next(action); @@ -182,8 +182,6 @@ static void tcf_ct_flow_table_add_action_meta(struct nf_conn *ct, #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) entry->ct_metadata.mark = READ_ONCE(ct->mark); #endif - ctinfo = dir == IP_CT_DIR_ORIGINAL ? IP_CT_ESTABLISHED : - IP_CT_ESTABLISHED_REPLY; /* aligns with the CT reference on the SKB nf_ct_set */ entry->ct_metadata.cookie = (unsigned long)ct | ctinfo; entry->ct_metadata.orig_dir = dir == IP_CT_DIR_ORIGINAL; @@ -237,22 +235,26 @@ static int tcf_ct_flow_table_add_action_nat(struct net *net, } static int tcf_ct_flow_table_fill_actions(struct net *net, - const struct flow_offload *flow, + struct flow_offload *flow, enum flow_offload_tuple_dir tdir, struct nf_flow_rule *flow_rule) { struct flow_action *action = &flow_rule->rule->action; int num_entries = action->num_entries; struct nf_conn *ct = flow->ct; + enum ip_conntrack_info ctinfo; enum ip_conntrack_dir dir; int i, err; switch (tdir) { case FLOW_OFFLOAD_DIR_ORIGINAL: dir = IP_CT_DIR_ORIGINAL; + ctinfo = IP_CT_ESTABLISHED; + set_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags); break; case FLOW_OFFLOAD_DIR_REPLY: dir = IP_CT_DIR_REPLY; + ctinfo = IP_CT_ESTABLISHED_REPLY; break; default: return -EOPNOTSUPP; @@ -262,7 +264,7 @@ static int tcf_ct_flow_table_fill_actions(struct net *net, if (err) goto err_nat; - tcf_ct_flow_table_add_action_meta(ct, dir, action); + tcf_ct_flow_table_add_action_meta(ct, dir, ctinfo, action); return 0; err_nat: From d5774cb6c55c8721c2daf57cc5e5345e3af286ea Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:58 +0100 Subject: [PATCH 5/7] net/sched: act_ct: set ctinfo in meta action depending on ct state Currently tcf_ct_flow_table_fill_actions() function assumes that only established connections can be offloaded and always sets ctinfo to either IP_CT_ESTABLISHED or IP_CT_ESTABLISHED_REPLY strictly based on direction without checking actual connection state. To enable UDP NEW connection offload set the ctinfo, metadata cookie and NF_FLOW_HW_ESTABLISHED flow_offload flags bit based on ct->status value. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/sched/act_ct.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index b9d3e338f72d..2cee3f9f83de 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -249,8 +249,10 @@ static int tcf_ct_flow_table_fill_actions(struct net *net, switch (tdir) { case FLOW_OFFLOAD_DIR_ORIGINAL: dir = IP_CT_DIR_ORIGINAL; - ctinfo = IP_CT_ESTABLISHED; - set_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags); + ctinfo = test_bit(IPS_SEEN_REPLY_BIT, &ct->status) ? + IP_CT_ESTABLISHED : IP_CT_NEW; + if (ctinfo == IP_CT_ESTABLISHED) + set_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags); break; case FLOW_OFFLOAD_DIR_REPLY: dir = IP_CT_DIR_REPLY; From 6a9bad0069cf306f3df6ac53cf02438d4e15f296 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:30:59 +0100 Subject: [PATCH 6/7] net/sched: act_ct: offload UDP NEW connections Modify the offload algorithm of UDP connections to the following: - Offload NEW connection as unidirectional. - When connection state changes to ESTABLISHED also update the hardware flow. However, in order to prevent act_ct from spamming offload add wq for every packet coming in reply direction in this state verify whether connection has already been updated to ESTABLISHED in the drivers. If that it the case, then skip flow_table and let conntrack handle such packets which will also allow conntrack to potentially promote the connection to ASSURED. - When connection state changes to ASSURED set the flow_table flow NF_FLOW_HW_BIDIRECTIONAL flag which will cause refresh mechanism to offload the reply direction. All other protocols have their offload algorithm preserved and are always offloaded as bidirectional. Note that this change tries to minimize the load on flow_table add workqueue. First, it tracks the last ctinfo that was offloaded by using new flow 'NF_FLOW_HW_ESTABLISHED' flag and doesn't schedule the refresh for reply direction packets when the offloads have already been updated with current ctinfo. Second, when 'add' task executes on workqueue it always update the offload with current flow state (by checking 'bidirectional' flow flag and obtaining actual ctinfo/cookie through meta action instead of caching any of these from the moment of scheduling the 'add' work) preventing the need from scheduling more updates if state changed concurrently while the 'add' work was pending on workqueue. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/sched/act_ct.c | 51 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 12 deletions(-) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index 2cee3f9f83de..b126f03c1bb6 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -369,7 +369,7 @@ static void tcf_ct_flow_tc_ifidx(struct flow_offload *entry, static void tcf_ct_flow_table_add(struct tcf_ct_flow_table *ct_ft, struct nf_conn *ct, - bool tcp) + bool tcp, bool bidirectional) { struct nf_conn_act_ct_ext *act_ct_ext; struct flow_offload *entry; @@ -388,6 +388,8 @@ static void tcf_ct_flow_table_add(struct tcf_ct_flow_table *ct_ft, ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL; } + if (bidirectional) + __set_bit(NF_FLOW_HW_BIDIRECTIONAL, &entry->flags); act_ct_ext = nf_conn_act_ct_ext_find(ct); if (act_ct_ext) { @@ -411,26 +413,34 @@ static void tcf_ct_flow_table_process_conn(struct tcf_ct_flow_table *ct_ft, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { - bool tcp = false; - - if ((ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY) || - !test_bit(IPS_ASSURED_BIT, &ct->status)) - return; + bool tcp = false, bidirectional = true; switch (nf_ct_protonum(ct)) { case IPPROTO_TCP: - tcp = true; - if (ct->proto.tcp.state != TCP_CONNTRACK_ESTABLISHED) + if ((ctinfo != IP_CT_ESTABLISHED && + ctinfo != IP_CT_ESTABLISHED_REPLY) || + !test_bit(IPS_ASSURED_BIT, &ct->status) || + ct->proto.tcp.state != TCP_CONNTRACK_ESTABLISHED) return; + + tcp = true; break; case IPPROTO_UDP: + if (!nf_ct_is_confirmed(ct)) + return; + if (!test_bit(IPS_ASSURED_BIT, &ct->status)) + bidirectional = false; break; #ifdef CONFIG_NF_CT_PROTO_GRE case IPPROTO_GRE: { struct nf_conntrack_tuple *tuple; - if (ct->status & IPS_NAT_MASK) + if ((ctinfo != IP_CT_ESTABLISHED && + ctinfo != IP_CT_ESTABLISHED_REPLY) || + !test_bit(IPS_ASSURED_BIT, &ct->status) || + ct->status & IPS_NAT_MASK) return; + tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; /* No support for GRE v1 */ if (tuple->src.u.gre.key || tuple->dst.u.gre.key) @@ -446,7 +456,7 @@ static void tcf_ct_flow_table_process_conn(struct tcf_ct_flow_table *ct_ft, ct->status & IPS_SEQ_ADJUST) return; - tcf_ct_flow_table_add(ct_ft, ct, tcp); + tcf_ct_flow_table_add(ct_ft, ct, tcp, bidirectional); } static bool @@ -625,13 +635,30 @@ static bool tcf_ct_flow_table_lookup(struct tcf_ct_params *p, flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); ct = flow->ct; + if (dir == FLOW_OFFLOAD_DIR_REPLY && + !test_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags)) { + /* Only offload reply direction after connection became + * assured. + */ + if (test_bit(IPS_ASSURED_BIT, &ct->status)) + set_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags); + else if (test_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags)) + /* If flow_table flow has already been updated to the + * established state, then don't refresh. + */ + return false; + } + if (tcph && (unlikely(tcph->fin || tcph->rst))) { flow_offload_teardown(flow); return false; } - ctinfo = dir == FLOW_OFFLOAD_DIR_ORIGINAL ? IP_CT_ESTABLISHED : - IP_CT_ESTABLISHED_REPLY; + if (dir == FLOW_OFFLOAD_DIR_ORIGINAL) + ctinfo = test_bit(IPS_SEEN_REPLY_BIT, &ct->status) ? + IP_CT_ESTABLISHED : IP_CT_NEW; + else + ctinfo = IP_CT_ESTABLISHED_REPLY; flow_offload_refresh(nf_ft, flow); nf_conntrack_get(&ct->ct_general); From df25455e5a489764508942b77b77de8f550e92cd Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 1 Feb 2023 17:31:00 +0100 Subject: [PATCH 7/7] netfilter: nf_conntrack: allow early drop of offloaded UDP conns Both synchronous early drop algorithm and asynchronous gc worker completely ignore connections with IPS_OFFLOAD_BIT status bit set. With new functionality that enabled UDP NEW connection offload in action CT malicious user can flood the conntrack table with offloaded UDP connections by just sending a single packet per 5tuple because such connections can no longer be deleted by early drop algorithm. To mitigate the issue allow both early drop and gc to consider offloaded UDP connections for deletion. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/netfilter/nf_conntrack_core.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index c00858344f02..9a830573480e 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1371,9 +1371,6 @@ static unsigned int early_drop_list(struct net *net, hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) { tmp = nf_ct_tuplehash_to_ctrack(h); - if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) - continue; - if (nf_ct_is_expired(tmp)) { nf_ct_gc_expired(tmp); continue; @@ -1443,11 +1440,14 @@ static bool gc_worker_skip_ct(const struct nf_conn *ct) static bool gc_worker_can_early_drop(const struct nf_conn *ct) { const struct nf_conntrack_l4proto *l4proto; + u8 protonum = nf_ct_protonum(ct); + if (test_bit(IPS_OFFLOAD_BIT, &ct->status) && protonum != IPPROTO_UDP) + return false; if (!test_bit(IPS_ASSURED_BIT, &ct->status)) return true; - l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); + l4proto = nf_ct_l4proto_find(protonum); if (l4proto->can_early_drop && l4proto->can_early_drop(ct)) return true; @@ -1504,7 +1504,8 @@ static void gc_worker(struct work_struct *work) if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) { nf_ct_offload_timeout(tmp); - continue; + if (!nf_conntrack_max95) + continue; } if (expired_count > GC_SCAN_EXPIRED_MAX) {