Date: Sun, 16 Mar 2008 00:05:36 +0100 From: Max Laier <max@love2party.net> To: freebsd-hackers@freebsd.org Subject: Review please: pfil FIRST/LAST Message-ID: <200803160005.45827.max@love2party.net>
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--nextPart3260259.LKNuToB0ym Content-Type: multipart/mixed; boundary="Boundary-01=_AZF3H42vZy1W3mH" Content-Transfer-Encoding: 7bit Content-Disposition: inline --Boundary-01=_AZF3H42vZy1W3mH Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi, attached is a small diff to allow pfil(9) consumers to force a sticky=20 position on the head/tail of the processing queue. This can be used to=20 do traffic conditioning kind of tasks w/o disturbing the other filters. =20 I will need this to implement carp(4) ip based load balancing. While=20 here I also removed a few paragraphs in BUGS which are no longer true=20 (since we are using rmlocks for pfil(9)). I'd appreciate review of the logic in pfil_list_add - just to make sure I=20 didn't botch it. Thanks. =2D-=20 /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News --Boundary-01=_AZF3H42vZy1W3mH Content-Type: text/x-diff; charset="us-ascii"; name="pfil_FIRST_LAST.diff" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="pfil_FIRST_LAST.diff" Index: sys/net/pfil.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D RCS file: /home/ncvs/src/sys/net/pfil.c,v retrieving revision 1.15 diff -u -r1.15 pfil.c =2D-- sys/net/pfil.c 25 Nov 2007 12:41:47 -0000 1.15 +++ sys/net/pfil.c 15 Mar 2008 22:35:50 -0000 @@ -182,6 +182,9 @@ struct packet_filter_hook *pfh2 =3D NULL; int err; =20 + if ((flags & (PFIL_FIRST|PFIL_LAST)) =3D=3D (PFIL_FIRST|PFIL_LAST)) + return (EDOOFUS); + /* Get memory */ if (flags & PFIL_IN) { pfh1 =3D (struct packet_filter_hook *)malloc(sizeof(*pfh1),=20 @@ -267,23 +270,50 @@ static int pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flag= s) { =2D struct packet_filter_hook *pfh; + struct packet_filter_hook *pfh, *fh, *lh; =20 /* * First make sure the hook is not already there. */ =2D TAILQ_FOREACH(pfh, list, pfil_link) + fh =3D TAILQ_FIRST(list); + lh =3D NULL; + TAILQ_FOREACH(pfh, list, pfil_link) { + /* fh is the first hook not marked PFIL_FIRST */ + if (pfh->pfil_flags & PFIL_FIRST) + fh =3D TAILQ_NEXT(pfh, pfil_link); + /* lh ist the last hook not marked PFIL_LAST */ + if (!(pfh->pfil_flags & PFIL_LAST)) + lh =3D pfh; if (pfh->pfil_func =3D=3D pfh1->pfil_func && pfh->pfil_arg =3D=3D pfh1->pfil_arg) return EEXIST; + } + /* * insert the input list in reverse order of the output list * so that the same path is followed in or out of the kernel. */ =2D if (flags & PFIL_IN) + if (flags & PFIL_FIRST) { TAILQ_INSERT_HEAD(list, pfh1, pfil_link); =2D else + } else if (flags & PFIL_LAST) { TAILQ_INSERT_TAIL(list, pfh1, pfil_link); + } else { + if (flags & PFIL_IN) { + if (fh) + TAILQ_INSERT_BEFORE(fh, pfh1, pfil_link); + else if (!TAILQ_EMPTY(list)) + TAILQ_INSERT_TAIL(list, pfh1, pfil_link); + else + TAILQ_INSERT_HEAD(list, pfh1, pfil_link); + } else { + if (lh) + TAILQ_INSERT_AFTER(list, lh, pfh1, pfil_link); + else if (!TAILQ_EMPTY(list)) + TAILQ_INSERT_HEAD(list, pfh1, pfil_link); + else + TAILQ_INSERT_TAIL(list, pfh1, pfil_link); + } + } =20 return 0; } Index: sys/net/pfil.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D RCS file: /home/ncvs/src/sys/net/pfil.h,v retrieving revision 1.17 diff -u -r1.17 pfil.h =2D-- sys/net/pfil.h 25 Nov 2007 12:41:47 -0000 1.17 +++ sys/net/pfil.h 15 Mar 2008 22:34:44 -0000 @@ -54,10 +54,12 @@ int pfil_flags; }; =20 =2D#define PFIL_IN 0x00000001 =2D#define PFIL_OUT 0x00000002 =2D#define PFIL_WAITOK 0x00000004 =2D#define PFIL_ALL (PFIL_IN|PFIL_OUT) +#define PFIL_IN (1<<0) +#define PFIL_OUT (1<<2) +#define PFIL_WAITOK (1<<3) +#define PFIL_ALL (PFIL_IN|PFIL_OUT) +#define PFIL_FIRST (1<<4) +#define PFIL_LAST (1<<5) =20 typedef TAILQ_HEAD(pfil_list, packet_filter_hook) pfil_list_t; =20 Index: share/man/man9/pfil.9 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D RCS file: /home/ncvs/src/share/man/man9/pfil.9,v retrieving revision 1.22 diff -u -r1.22 pfil.9 =2D-- share/man/man9/pfil.9 18 Sep 2006 15:24:20 -0000 1.22 +++ share/man/man9/pfil.9 15 Mar 2008 22:50:48 -0000 @@ -28,7 +28,7 @@ .\" .\" $FreeBSD: src/share/man/man9/pfil.9,v 1.22 2006/09/18 15:24:20 ru Exp $ .\" =2D.Dd September 29, 2004 +.Dd March 15, 2008 .Dt PFIL 9 .Os .Sh NAME @@ -115,6 +115,11 @@ or .Dv PFIL_OUT ) that the packet is traveling. +.Dv PFIL_FIRST +and +.Dv PFIL_LAST +can be used to force a sticky positioning of the hook in the front or the +tail of the processing queue respectively. The filter may change which mbuf the .Vt "mbuf\ **" argument references. @@ -134,15 +139,6 @@ .Fn pfil_remove_hook functions return 0 if successful. =2DIf called with flag =2D.Dv PFIL_WAITOK , =2D.Fn pfil_remove_hook =2Dis expected to always succeed. =2D.Pp =2DThe =2D.Fn pfil_head_unregister =2Dfunction =2Dmight sleep! .Sh SEE ALSO .Xr bpf 4 , .Xr if_bridge 4 @@ -203,14 +199,3 @@ .Dv AF_INET6 traffic according to its sysctl settings, but contrary to the above statements, the data is provided in host byte order. =2D.Pp =2DWhen a =2D.Vt pfil_head =2Dis being modified, no traffic is diverted =2D(to avoid deadlock). =2DThis means that traffic may be dropped unconditionally for a short period =2Dof time. =2D.Fn pfil_run_hooks =2Dwill return =2D.Er ENOBUFS =2Dto indicate this. --Boundary-01=_AZF3H42vZy1W3mH-- --nextPart3260259.LKNuToB0ym Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBH3FZJXyyEoT62BG0RAulNAJ4nREpIJr8Ykor+QHlv1jmBSTN8EACfZDzr 1QWjz4gk8YD3PS0TJ6Rv6zw= =RP4z -----END PGP SIGNATURE----- --nextPart3260259.LKNuToB0ym--
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