A *QUICK* pass through this man page to make it conform to mdoc
standards and to clean up some of the English. The job is nowhere complete. This man page would be a good project for someone who knows something about the firewall software, and would like to contribute to the documentation effort. Many of the things in this man page are out of date and do not reflect reality.
This commit is contained in:
Mike Pritchard
parent
09b4b08649
commit
b805452cc8
@ -1,16 +1,16 @@
|
||||
.Dd November 16, 1994
|
||||
.Dt IPFW(4)/IPACCT 4
|
||||
.Dt IPFIREWALL 4
|
||||
.Os
|
||||
.Sh NAME
|
||||
|
||||
ipfirewall,ipfw - IP packets filter.
|
||||
ipaccounting,ipacct - IP packets/traffic accounting.
|
||||
|
||||
.Nm ipfirewall,
|
||||
.Nm ipfw ,
|
||||
.Nm ipaccounting ,
|
||||
.Nm ipacct
|
||||
.Nd IP packet filter and traffic accounting.
|
||||
.Sh SYNOPSIS
|
||||
#include <netinet/ip_fw.h>
|
||||
|
||||
setsockopt(raw_socket,IPPROTO_IP,<ipfw/ipacct option>,
|
||||
<struct ip|struct ipfw>,<size>)
|
||||
.Fd #include <netinet/ip_fw.h>
|
||||
.Ft int
|
||||
.Fn setsockopt raw_socket IPPROTO_IP "ipfw/ipacct option" "struct ip | struct ipfw" size
|
||||
|
||||
Ipfw options:
|
||||
IP_FW_ADD_BLK - add entry to blocking chain.
|
||||
@ -72,20 +72,21 @@ of incoming and/or forwarding packets on the protocol+source/destination
|
||||
address/ports base.
|
||||
Ipaccounting (later ipacct) is a system facility,which allows counting
|
||||
of incoming,outgoing and forwarding traffic by packet/byte count.
|
||||
|
||||
.Pp
|
||||
Basic idea is that every packet checked against number of entries
|
||||
in several chains.There are 3 chains:
|
||||
in several chains. There are 3 chains:
|
||||
Blocking - this chain defines whenever packet should be accepted
|
||||
ever for local delivery or for forwarding.
|
||||
Forwarding - this chain defines whenever packet should be accepted
|
||||
for forwarding only.
|
||||
Accounting - this chain defines types of packets , which should be
|
||||
counted.
|
||||
|
||||
Entries added to chains by means of setsockopt() call on RAW IP socket.
|
||||
.Pp
|
||||
Options to add/remove specific entries or to flush all entries described
|
||||
above. Value passed to setsockopt() is a value of struct ip_fw for
|
||||
entry. If entry added , it checked by such rules that when we start
|
||||
above. Value passed to
|
||||
.Fn setsockopt
|
||||
is a value of struct ip_fw for
|
||||
entry. If an entry is added, it checked by such rules that when we start
|
||||
searching chain for matching entry the first matching is the best match,
|
||||
[ or at least one of them :^) ].
|
||||
That means:
|
||||
@ -94,12 +95,13 @@ searching chain for matching entry the first matching is the best match,
|
||||
* Later go entries with wider ranges of ports and addresses.
|
||||
* Later entries matching every port for some address range.
|
||||
* Later universal entries matching any protocol.
|
||||
.Pp
|
||||
While deleting entry, every entry which is equal to that passed to
|
||||
.Fn setsockopt
|
||||
will be removed. Flush removes all entries.
|
||||
Each entry has several fields by which packets are matched:
|
||||
|
||||
While deleting entry , every entry which equal to that passed to
|
||||
setsockopt() will be removed.
|
||||
Flush removes all entries.
|
||||
|
||||
Every entry have several fields,by which packets matched:
|
||||
struct ip_fw *next - next entry in chain.(Set internally)
|
||||
|
||||
struct in_addr src - source address to be matched.
|
||||
@ -131,55 +133,54 @@ Every entry have several fields,by which packets matched:
|
||||
u_long p_cnt - packets count for ipacct entries.
|
||||
u_long b_cnt - bytes count for ipacct entries.
|
||||
|
||||
Packet matching proceeds in following way:
|
||||
Packet matching proceeds in the following manner:
|
||||
|
||||
a) If packet entry protocol set to ALL, see c).
|
||||
|
||||
b) If entry protocol set to TCP/UDP/ICMP and packet protocol
|
||||
different - no match,if packet protocol and entry protocol
|
||||
different - no match, if packet protocol and entry protocol
|
||||
same - continue.
|
||||
|
||||
c) If source address pattern does not equal to packets sources address
|
||||
masked with src_mask , or destination pattern not equal to packets
|
||||
masked with src_mask, or destination pattern not equal to packets
|
||||
destination address masked with dst_mask - no match.
|
||||
If they does and protocol set to ALL/ICMP - got match.
|
||||
If they does and protocol set to TCP/UDP - continue.
|
||||
|
||||
d) If src port doesn't match or dst port doesn't match - all
|
||||
packet don't match. If they does - got match.
|
||||
|
||||
packet don't match. If they do - got match.
|
||||
.Pp
|
||||
In ipfw packet matched consequently against every chain entry.
|
||||
Search continues untill first matching entry found.If IP_FW_F_ACCEPT
|
||||
flag set - packet accepted.If it is not set - packet denied.
|
||||
If no matching entry found , all unmatched packets ever accepted or
|
||||
flag set - packet accepted. If it is not set - packet denied.
|
||||
If no matching entry found, all unmatched packets ever accepted or
|
||||
denied depending on global policy value. It can be set with
|
||||
IP_FW_POLICY raw socket option. Deny value is 0, other values
|
||||
(default 1) is accept.
|
||||
|
||||
IP_FW_POLICY raw socket option. The value for deny is 0,
|
||||
and 1 for accept.
|
||||
.Pp
|
||||
Entries can be added with IP_FW_F_PRN flag set.If kernel compiled
|
||||
with IPFIREWALL_VERBOSE option,packets matching this entries will
|
||||
be printed by kernel printf's.
|
||||
|
||||
.Pp
|
||||
If some chain is empty,every packet accepted by this chain no
|
||||
matter what default policy is.
|
||||
|
||||
.Pp
|
||||
To check whenever or not packet denied by some chain , checking
|
||||
options to setsockopt() can be issued. Then the argument is
|
||||
a buffer representing ip packet,thus it has to be
|
||||
struct ip + struct tcphdr .
|
||||
Then setsockopt() return value 0 on accept or another on deny.
|
||||
|
||||
.Pp
|
||||
Ipaccounting entries added the same way as ipfw ones.Packet checked
|
||||
against all entries in chain and values of p_cnt and b_cnt in matching
|
||||
entries rised.p_cnt rises by 1 and b_cnt by ip_len value of ip packet.
|
||||
Thus all traffic size counted including IP headers.
|
||||
|
||||
.Pp
|
||||
If IP_FW_F_BIDIR flag is set in accounting entry,packets counted are
|
||||
those which match entry in standard way along with packets which match
|
||||
entry while their source and destination addr/port pairs swapped.
|
||||
|
||||
.Pp
|
||||
Zero option allows all accounting to be cleared.
|
||||
|
||||
.Sh DIAGNOSTICS
|
||||
|
||||
[EINVAL] The IP option field was improperly formed; an option
|
||||
@ -187,16 +188,16 @@ Zero option allows all accounting to be cleared.
|
||||
the option buffer provided.An structural error in
|
||||
ip_fw structure occurred (n_src_p+n_dst_p too big,
|
||||
ports set for ALL/ICMP protocols etc.)
|
||||
|
||||
.Sh SEE ALSO
|
||||
|
||||
ip(4), setsockopt(2), kvm_nlist(3), kvm_read(3)
|
||||
|
||||
.Xr setsockopt 2 ,
|
||||
.Xr kvm_nlist 3 ,
|
||||
.Xr kvm_read 3 ,
|
||||
.Xr ip 4
|
||||
.Sh BUGS
|
||||
Ipfw/ipacct facilities are new and , although serious bugs has
|
||||
been tracked,some less important ones expected.
|
||||
This man page is mostly out of date and should be rewritten.
|
||||
|
||||
The ipfw/ipacct facilities are new and, although serious bugs have
|
||||
been tracked, some less important ones are expected.
|
||||
.Pp
|
||||
This man page is mostly out of date and should be rewritten.
|
||||
.Sh HISTORY
|
||||
Ipfw facility has been initially written as package to BSDI
|
||||
by Daniel Boulet <danny@BouletFermat.ab.ca>.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user