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path: root/include/net/netfilter/nf_nat_helper.h (follow)
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2013-09-23netfilter: Remove extern from function prototypesJoe Perches1-18/+11
There are a mix of function prototypes with and without extern in the kernel sources. Standardize on not using extern for function prototypes. Function prototypes don't need to be written with extern. extern is assumed by the compiler. Its use is as unnecessary as using auto to declare automatic/local variables in a block. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-28netfilter: nf_conntrack: make sequence number adjustments usuable without NATPatrick McHardy1-19/+0
Split out sequence number adjustments from NAT and move them to the conntrack core to make them usable for SYN proxying. The sequence number adjustment information is moved to a seperate extend. The extend is added to new conntracks when a NAT mapping is set up for a connection using a helper. As a side effect, this saves 24 bytes per connection with NAT in the common case that a connection does not have a helper assigned. Signed-off-by: Patrick McHardy <kaber@trash.net> Tested-by: Martin Topholm <mph@one.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2013-07-31netfilter: nf_nat: change sequence number adjustments to 32 bitsPatrick McHardy1-3/+3
Using 16 bits is too small, when many adjustments happen the offsets might overflow and break the connection. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2012-08-30netfilter: nf_nat: add protoff argument to packet mangling functionsPatrick McHardy1-3/+8
For mangling IPv6 packets the protocol header offset needs to be known by the NAT packet mangling functions. Add a so far unused protoff argument and convert the conntrack and NAT helpers to use it in preparation of IPv6 NAT. Signed-off-by: Patrick McHardy <kaber@trash.net>
2012-06-16netfilter: nfnetlink_queue: add NAT TCP sequence adjustment if packet mangledPablo Neira Ayuso1-0/+4
User-space programs that receive traffic via NFQUEUE may mangle packets. If NAT is enabled, this usually puzzles sequence tracking, leading to traffic disruptions. With this patch, nfnl_queue will make the corresponding NAT TCP sequence adjustment if: 1) The packet has been mangled, 2) the NFQA_CFG_F_CONNTRACK flag has been set, and 3) NAT is detected. There are some records on the Internet complaning about this issue: http://stackoverflow.com/questions/260757/packet-mangling-utilities-besides-iptables By now, we only support TCP since we have no helpers for DCCP or SCTP. Better to add this if we ever have some helper over those layer 4 protocols. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2010-02-11netfilter: nf_nat: support mangling a single TCP packet multiple timesPatrick McHardy1-7/+25
nf_nat_mangle_tcp_packet() can currently only handle a single mangling per window because it only maintains two sequence adjustment positions: the one before the last adjustment and the one after. This patch makes sequence number adjustment tracking in nf_nat_mangle_tcp_packet() optional and allows a helper to manually update the offsets after the packet has been fully handled. Signed-off-by: Patrick McHardy <kaber@trash.net>
2009-11-06netfilter: nf_nat: fix NAT issue in 2.6.30.4+Jozsef Kadlecsik1-0/+4
Vitezslav Samel discovered that since 2.6.30.4+ active FTP can not work over NAT. The "cause" of the problem was a fix of unacknowledged data detection with NAT (commit a3a9f79e361e864f0e9d75ebe2a0cb43d17c4272). However, actually, that fix uncovered a long standing bug in TCP conntrack: when NAT was enabled, we simply updated the max of the right edge of the segments we have seen (td_end), by the offset NAT produced with changing IP/port in the data. However, we did not update the other parameter (td_maxend) which is affected by the NAT offset. Thus that could drift away from the correct value and thus resulted breaking active FTP. The patch below fixes the issue by *not* updating the conntrack parameters from NAT, but instead taking into account the NAT offsets in conntrack in a consistent way. (Updating from NAT would be more harder and expensive because it'd need to re-calculate parameters we already calculated in conntrack.) Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-14[NETFILTER]: nf_nat: kill helper and seq_adjust hooksPatrick McHardy1-0/+3
Connection tracking helpers (specifically FTP) need to be called before NAT sequence numbers adjustments are performed to be able to compare them against previously seen ones. We've introduced two new hooks around 2.6.11 to maintain this ordering when NAT modules were changed to get called from conntrack helpers directly. The cost of netfilter hooks is quite high and sequence number adjustments are only rarely needed however. Add a RCU-protected sequence number adjustment function pointer and call it from IPv4 conntrack after calling the helper. Signed-off-by: Patrick McHardy <kaber@trash.net>
2007-10-15[NETFILTER]: Replace sk_buff ** with sk_buff *Herbert Xu1-3/+3
With all the users of the double pointers removed, this patch mops up by finally replacing all occurances of sk_buff ** in the netfilter API by sk_buff *. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02[NETFILTER]: Add NAT support for nf_conntrackJozsef Kadlecsik1-0/+32
Add NAT support for nf_conntrack. Joint work of Jozsef Kadlecsik, Yasuyuki Kozakai, Martin Josefsson and myself. Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>