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2018-05-23netfilter: nf_nat: add nat type hooks to nat coreFlorian Westphal1-27/+55
Currently the packet rewrite and instantiation of nat NULL bindings happens from the protocol specific nat backend. Invocation occurs either via ip(6)table_nat or the nf_tables nat chain type. Invocation looks like this (simplified): NF_HOOK() | `---iptable_nat | `---> nf_nat_l3proto_ipv4 -> nf_nat_packet | new packet? pass skb though iptables nat chain | `---> iptable_nat: ipt_do_table In nft case, this looks the same (nft_chain_nat_ipv4 instead of iptable_nat). This is a problem for two reasons: 1. Can't use iptables nat and nf_tables nat at the same time, as the first user adds a nat binding (nf_nat_l3proto_ipv4 adds a NULL binding if do_table() did not find a matching nat rule so we can detect post-nat tuple collisions). 2. If you use e.g. nft_masq, snat, redir, etc. uses must also register an empty base chain so that the nat core gets called fro NF_HOOK() to do the reverse translation, which is neither obvious nor user friendly. After this change, the base hook gets registered not from iptable_nat or nftables nat hooks, but from the l3 nat core. iptables/nft nat base hooks get registered with the nat core instead: NF_HOOK() | `---> nf_nat_l3proto_ipv4 -> nf_nat_packet | new packet? pass skb through iptables/nftables nat chains | +-> iptables_nat: ipt_do_table +-> nft nat chain x `-> nft nat chain y The nat core deals with null bindings and reverse translation. When no mapping exists, it calls the registered nat lookup hooks until one creates a new mapping. If both iptables and nftables nat hooks exist, the first matching one is used (i.e., higher priority wins). Also, nft users do not need to create empty nat hooks anymore, nat core always registers the base hooks that take care of reverse/reply translation. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-05-23netfilter: nf_nat: move common nat code to nat coreFlorian Westphal1-53/+2
Copy-pasted, both l3 helpers almost use same code here. Split out the common part into an 'inet' helper. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-05-06netfilter: nf_nat: remove unused ct arg from lookup functionsFlorian Westphal1-9/+5
Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-04-24netfilter: add NAT support for shifted portmap rangesThierry Du Tre1-2/+2
This is a patch proposal to support shifted ranges in portmaps. (i.e. tcp/udp incoming port 5000-5100 on WAN redirected to LAN 192.168.1.5:2000-2100) Currently DNAT only works for single port or identical port ranges. (i.e. ports 5000-5100 on WAN interface redirected to a LAN host while original destination port is not altered) When different port ranges are configured, either 'random' mode should be used, or else all incoming connections are mapped onto the first port in the redirect range. (in described example WAN:5000-5100 will all be mapped to 192.168.1.5:2000) This patch introduces a new mode indicated by flag NF_NAT_RANGE_PROTO_OFFSET which uses a base port value to calculate an offset with the destination port present in the incoming stream. That offset is then applied as index within the redirect port range (index modulo rangewidth to handle range overflow). In described example the base port would be 5000. An incoming stream with destination port 5004 would result in an offset value 4 which means that the NAT'ed stream will be using destination port 2004. Other possibilities include deterministic mapping of larger or multiple ranges to a smaller range : WAN:5000-5999 -> LAN:5000-5099 (maps WAN port 5*xx to port 51xx) This patch does not change any current behavior. It just adds new NAT proto range functionality which must be selected via the specific flag when intended to use. A patch for iptables (libipt_DNAT.c + libip6t_DNAT.c) will also be proposed which makes this functionality immediately available. Signed-off-by: Thierry Du Tre <thierry@dtsystems.be> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-01-08netfilter: remove defensive check on malformed packets from raw socketsPablo Neira Ayuso1-10/+0
Users cannot forge malformed IPv4/IPv6 headers via raw sockets that they can inject into the stack. Specifically, not for IPv4 since 55888dfb6ba7 ("AF_RAW: Augment raw_send_hdrinc to expand skb to fit iphdr->ihl (v2)"). IPv6 raw sockets also ensure that packets have a well-formed IPv6 header available in the skbuff. At quick glance, br_netfilter also validates layer 3 headers and it drops malformed both IPv4 and IPv6 packets. Therefore, let's remove this defensive check all over the place. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-10-18ipv4: mark expected switch fall-throughsGustavo A. R. Silva1-1/+2
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Notice that in some cases I placed the "fall through" comment on its own line, which is what GCC is expecting to find. Addresses-Coverity-ID: 115108 Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-04net: Replace NF_CT_ASSERT() with WARN_ON().Varsha Rao1-3/+3
This patch removes NF_CT_ASSERT() and instead uses WARN_ON(). Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
2017-04-26netfilter: don't attach a nat extension by defaultFlorian Westphal1-3/+1
nowadays the NAT extension only stores the interface index (used to purge connections that got masqueraded when interface goes down) and pptp nat information. Previous patches moved nf_ct_nat_ext_add to those places that need it. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-04-15netfilter: remove nf_ct_is_untrackedFlorian Westphal1-4/+0
This function is now obsolete and always returns false. This change has no effect on generated code. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-03-08netfilter: don't track fragmented packetsFlorian Westphal1-5/+0
Andrey reports syzkaller splat caused by NF_CT_ASSERT(!ip_is_fragment(ip_hdr(skb))); in ipv4 nat. But this assertion (and the comment) are wrong, this function does see fragments when IP_NODEFRAG setsockopt is used. As conntrack doesn't track packets without complete l4 header, only the first fragment is tracked. Because applying nat to first packet but not the rest makes no sense this also turns off tracking of all fragments. Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2016-03-14netfilter: Allow calling into nat helper without skb_dst.Jarno Rajahalme1-22/+8
NAT checksum recalculation code assumes existence of skb_dst, which becomes a problem for a later patch in the series ("openvswitch: Interface with NAT."). Simplify this by removing the check on skb_dst, as the checksum will be dealt with later in the stack. Suggested-by: Pravin Shelar <pshelar@nicira.com> Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-12-15net: Eliminate NETIF_F_GEN_CSUM and NETIF_F_V[46]_CSUMTom Herbert1-1/+2
These netif flags are unnecessary convolutions. It is more straightforward to just use NETIF_F_HW_CSUM, NETIF_F_IP_CSUM, and NETIF_F_IPV6_CSUM directly. This patch also: - Cleans up can_checksum_protocol - Simplifies netdev_intersect_features Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-29ipv4: Pass struct net into ip_route_me_harderEric W. Biederman1-1/+1
Don't make ip_route_me_harder guess which network namespace it is routing in, pass the network namespace in. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-09-18netfilter: Pass net into nf_xfrm_me_harderEric W. Biederman1-2/+2
Instead of calling dev_net on a likley looking network device pass state->net into nf_xfrm_me_harder. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-09-18netfilter: Pass priv instead of nf_hook_ops to netfilter hooksEric W. Biederman1-12/+12
Only pass the void *priv parameter out of the nf_hook_ops. That is all any of the functions are interested now, and by limiting what is passed it becomes simpler to change implementation details. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-09-18inet netfilter: Prefer state->hook to ops->hooknumEric W. Biederman1-7/+7
The values of nf_hook_state.hook and nf_hook_ops.hooknum must be the same by definition. We are more likely to access the fields in nf_hook_state over the fields in nf_hook_ops so with a little luck this results in fewer cache line misses, and slightly more consistent code. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-08-17net: Change pseudohdr argument of inet_proto_csum_replace* to be a boolTom Herbert1-2/+2
inet_proto_csum_replace4,2,16 take a pseudohdr argument which indicates the checksum field carries a pseudo header. This argument should be a boolean instead of an int. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-04netfilter: Pass nf_hook_state through nf_nat_ipv4_{in,out,fn,local_fn}().David S. Miller1-18/+15
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-02netfilter: nat: move specific NAT IPv4 to corePablo Neira Ayuso1-0/+199
Move the specific NAT IPv4 core functions that are called from the hooks from iptable_nat.c to nf_nat_l3proto_ipv4.c. This prepares the ground to allow iptables and nft to use the same NAT engine code that comes in a follow up patch. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2014-06-30netfilter: use IS_ENABLED() macroDuan Jiong1-0/+4
replace: #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) with #if IS_ENABLED(CONFIG_NF_CT_NETLINK) replace: #if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE) with #if !IS_ENABLED(CONFIG_NF_NAT) replace: #if !defined(CONFIG_NF_CONNTRACK) && !defined(CONFIG_NF_CONNTRACK_MODULE) with #if !IS_ENABLED(CONFIG_NF_CONNTRACK) And add missing: IS_ENABLED(CONFIG_NF_CT_NETLINK) in net/ipv{4,6}/netfilter/nf_nat_l3proto_ipv{4,6}.c Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2012-08-30netfilter: add protocol independent NAT corePatrick McHardy1-0/+281
Convert the IPv4 NAT implementation to a protocol independent core and address family specific modules. Signed-off-by: Patrick McHardy <kaber@trash.net>