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path: root/net/netfilter/nf_nat_proto_udp.c
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2020-05-14netfilter: nat: never update the UDP checksum when it's 0Guillaume Nault
commit ea64d8d6c675c0bb712689b13810301de9d8f77a upstream. If the UDP header of a local VXLAN endpoint is NAT-ed, and the VXLAN device has disabled UDP checksums and enabled Tx checksum offloading, then the skb passed to udp_manip_pkt() has hdr->check == 0 (outer checksum disabled) and skb->ip_summed == CHECKSUM_PARTIAL (inner packet checksum offloaded). Because of the ->ip_summed value, udp_manip_pkt() tries to update the outer checksum with the new address and port, leading to an invalid checksum sent on the wire, as the original null checksum obviously didn't take the old address and port into account. So, we can't take ->ip_summed into account in udp_manip_pkt(), as it might not refer to the checksum we're acting on. Instead, we can base the decision to update the UDP checksum entirely on the value of hdr->check, because it's null if and only if checksum is disabled: * A fully computed checksum can't be 0, since a 0 checksum is represented by the CSUM_MANGLED_0 value instead. * A partial checksum can't be 0, since the pseudo-header always adds at least one non-zero value (the UDP protocol type 0x11) and adding more values to the sum can't make it wrap to 0 as the carry is then added to the wrapped number. * A disabled checksum uses the special value 0. The problem seems to be there from day one, although it was probably not visible before UDP tunnels were implemented. Fixes: 5b1158e909ec ("[NETFILTER]: Add NAT support for nf_conntrack") Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-24netfilter: add NAT support for shifted portmap rangesThierry Du Tre
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>
2017-01-03netfilter: nat: merge udp and udplite helpersFlorian Westphal
udplite nat was copied from udp nat, they are virtually 100% identical. Not really surprising given udplite is just udp with partial csum coverage. old: text data bss dec hex filename 11606 1457 210 13273 33d9 nf_nat.ko 330 0 2 332 14c nf_nat_proto_udp.o 276 0 2 278 116 nf_nat_proto_udplite.o new: text data bss dec hex filename 11598 1457 210 13265 33d1 nf_nat.ko 640 0 4 644 284 nf_nat_proto_udp.o Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-08-17net: Change pseudohdr argument of inet_proto_csum_replace* to be a boolTom Herbert
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>
2014-06-30netfilter: use IS_ENABLED() macroDuan Jiong
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 McHardy
Convert the IPv4 NAT implementation to a protocol independent core and address family specific modules. Signed-off-by: Patrick McHardy <kaber@trash.net>