From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: Re: [RFC Patch] net: reserve ports for applications using fixed port numbers Date: Wed, 03 Feb 2010 13:15:45 +0800 Message-ID: <4B690681.6070908@redhat.com> References: <20100203043332.3817.27932.sendpatchset@localhost.localdomain> <1265171993.3274.3.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Neil Horman , linux-sctp-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Miller To: Eric Dumazet Return-path: In-Reply-To: <1265171993.3274.3.camel@edumazet-laptop> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org Eric Dumazet wrote: > Le mardi 02 f=C3=A9vrier 2010 =C3=A0 23:30 -0500, Amerigo Wang a =C3=A9= crit : >> This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports, >> it can be used like ip_local_port_range, but this is used to >> reserve ports for third-party applications which use fixed >> port numbers within ip_local_port_range. >> >> This only affects the applications which call socket functions >> like bind(2) with port number 0, to prevent the kernel getting the p= orts >> within the specified range for them. For applications which use fixe= d >> port number, it will have no effects. >> >> Any comments are welcome. >> >> Signed-off-by: WANG Cong >> Cc: David Miller >> Cc: Neil Horman >> Cc: Eric Dumazet >=20 >> .procname =3D "igmp_max_memberships", >> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c >> index f0126fd..83045ca 100644 >> --- a/net/ipv4/udp.c >> +++ b/net/ipv4/udp.c >> @@ -210,8 +210,11 @@ int udp_lib_get_port(struct sock *sk, unsigned = short snum, >> inet_get_local_port_range(&low, &high); >> remaining =3D (high - low) + 1; >> =20 >> +again: >> rand =3D net_random(); >> first =3D (((u64)rand * remaining) >> 32) + low; >> + if (inet_is_reserved_local_port(first)) >> + goto again; >> /* >> * force rand to be an odd multiple of UDP_HTABLE_SIZE >> */ >=20 > Unless I misread the patch, you are checking only the 'first' port th= at > udp_lib_get_port() chose. >=20 > I would use inet_get_local_reserved_ports(&min_res, &max_res); > and check every port that we chose in the loop to avoid it if necessa= ry. >=20 Hmm, right, 'first' is used to do iteration, but I did missed 'last'. Thanks! I will fix this in the next update. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html