Re: [PATCH] netfilter: add CHECKSUM target
Am 11.07.2010 12:47, schrieb Michael S. Tsirkin: On Fri, Jul 09, 2010 at 05:17:36PM +0200, Patrick McHardy wrote: Am 09.07.2010 00:29, schrieb Michael S. Tsirkin: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 60, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill I'm not sure this is something we want to merge upstream and support indefinitely. Dave suggested this as a temporary out-of-tree workaround until the majority of guest dhcp clients are fixed. Has anything changed that makes this course of action impractical? If I understand what Dave said correctly, it's up to you ... The arguments for putting this upstream are: Given the track record, I wouldn't hope for quick fix in the majority of guest dhcp clients, unfortunately :(. We are talking years here. Even after that, one of the uses of virtualization is to keep old guests running. So yes, I think we'll keep using work-arounds for this for a very long time. Further, since we have to add the module and we have to teach management to program it, it will be much less painful for everyone involved if we can put the code upstream, rather than forking management code. Fair enough, its simple enough that I don't expect much maintenance overhead. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Fri, Jul 09, 2010 at 03:18:14PM +0800, Herbert Xu wrote: On Fri, Jul 09, 2010 at 01:29:13AM +0300, Michael S. Tsirkin wrote: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 60, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill Signed-off-by: Michael S. Tsirkin m...@redhat.com I'd think that this target would be protocol-agnostic, no? Meaning it should go into net/netfilter/? Will do. Cheers, -- Email: Herbert Xu herb...@gondor.apana.org.au Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Sun, Jul 11, 2010 at 12:21:17PM +0300, Michael S. Tsirkin wrote: I'd think that this target would be protocol-agnostic, no? Meaning it should go into net/netfilter/? Will do. Right, and you should get rid of any IPv4 dependencies. Thanks, -- Email: Herbert Xu herb...@gondor.apana.org.au Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Fri, Jul 09, 2010 at 05:17:36PM +0200, Patrick McHardy wrote: Am 09.07.2010 00:29, schrieb Michael S. Tsirkin: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 60, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill I'm not sure this is something we want to merge upstream and support indefinitely. Dave suggested this as a temporary out-of-tree workaround until the majority of guest dhcp clients are fixed. Has anything changed that makes this course of action impractical? If I understand what Dave said correctly, it's up to you ... The arguments for putting this upstream are: Given the track record, I wouldn't hope for quick fix in the majority of guest dhcp clients, unfortunately :(. We are talking years here. Even after that, one of the uses of virtualization is to keep old guests running. So yes, I think we'll keep using work-arounds for this for a very long time. Further, since we have to add the module and we have to teach management to program it, it will be much less painful for everyone involved if we can put the code upstream, rather than forking management code. -- MST -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Fri, Jul 09, 2010 at 11:56:26AM +0200, Jan Engelhardt wrote:
On Friday 2010-07-09 00:29, Michael S. Tsirkin wrote:
include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++
net/ipv4/netfilter/Kconfig | 16 ++
net/ipv4/netfilter/Makefile |1 +
net/ipv4/netfilter/ipt_CHECKSUM.c | 72
+++
New modules should use xt.
I tried moving the module to xt_CHECKSUM but now
iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM
--checksum-fill
does not to load the module.
It seems that xt_request_find_target in x_tables uses the prefix 'ip' for a
module.
What am I missing?
+static unsigned int
+checksum_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+if (skb-ip_summed == CHECKSUM_PARTIAL) {
+skb_checksum_help(skb);
+}
- {}
--
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Re: [PATCH] netfilter: add CHECKSUM target
On Sun, Jul 11, 2010 at 8:27 PM, Michael S. Tsirkin m...@redhat.com wrote: On Fri, Jul 09, 2010 at 11:56:26AM +0200, Jan Engelhardt wrote: On Friday 2010-07-09 00:29, Michael S. Tsirkin wrote: include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++ net/ipv4/netfilter/Kconfig | 16 ++ net/ipv4/netfilter/Makefile | 1 + net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++ New modules should use xt. I tried moving the module to xt_CHECKSUM but now iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill does not to load the module. It seems that xt_request_find_target in x_tables uses the prefix 'ip' for a module. What am I missing? You should add MODULE_ALIAS clause, i.e. MODULE_ALIAS(ipt_CHECKSUM); -- Regards, Changli Gao(xiao...@gmail.com) -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Sunday 2010-07-11 14:27, Michael S. Tsirkin wrote: include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++ net/ipv4/netfilter/Kconfig | 16 ++ net/ipv4/netfilter/Makefile |1 + net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++ New modules should use xt. I tried moving the module to xt_CHECKSUM but now iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill does not to load the module. It seems that xt_request_find_target in x_tables uses the prefix 'ip' for a module. What am I missing? MODULE_ALIAS like the others have. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Sun, Jul 11, 2010 at 02:45:49PM +0200, Jan Engelhardt wrote: On Sunday 2010-07-11 14:27, Michael S. Tsirkin wrote: include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++ net/ipv4/netfilter/Kconfig | 16 ++ net/ipv4/netfilter/Makefile |1 + net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++ New modules should use xt. I tried moving the module to xt_CHECKSUM but now iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill does not to load the module. It seems that xt_request_find_target in x_tables uses the prefix 'ip' for a module. What am I missing? MODULE_ALIAS like the others have. Worked for me, thanks! -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Sun, Jul 11, 2010 at 08:45:01PM +0800, Changli Gao wrote: On Sun, Jul 11, 2010 at 8:27 PM, Michael S. Tsirkin m...@redhat.com wrote: On Fri, Jul 09, 2010 at 11:56:26AM +0200, Jan Engelhardt wrote: On Friday 2010-07-09 00:29, Michael S. Tsirkin wrote: include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++ net/ipv4/netfilter/Kconfig | 16 ++ net/ipv4/netfilter/Makefile | 1 + net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++ New modules should use xt. I tried moving the module to xt_CHECKSUM but now iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill does not to load the module. It seems that xt_request_find_target in x_tables uses the prefix 'ip' for a module. What am I missing? You should add MODULE_ALIAS clause, i.e. MODULE_ALIAS(ipt_CHECKSUM); This worked, thanks! -- Regards, Changli Gao(xiao...@gmail.com) -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Fri, Jul 09, 2010 at 01:29:13AM +0300, Michael S. Tsirkin wrote: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 60, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill Signed-off-by: Michael S. Tsirkin m...@redhat.com I'd think that this target would be protocol-agnostic, no? Cheers, -- Email: Herbert Xu herb...@gondor.apana.org.au Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Friday 2010-07-09 00:29, Michael S. Tsirkin wrote:
include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++
net/ipv4/netfilter/Kconfig | 16 ++
net/ipv4/netfilter/Makefile |1 +
net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++
New modules should use xt.
+static unsigned int
+checksum_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+ if (skb-ip_summed == CHECKSUM_PARTIAL) {
+ skb_checksum_help(skb);
+ }
- {}
--
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the body of a message to majord...@vger.kernel.org
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Re: [PATCH] netfilter: add CHECKSUM target
Am 09.07.2010 00:29, schrieb Michael S. Tsirkin: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. The problem happens in the field with virtualized applications. For reference, see Red Hat bz 60, as well as http://www.spinics.net/lists/kvm/msg37660.html Typical expected use (helps old dhclient binary running in a VM): iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM --checksum-fill I'm not sure this is something we want to merge upstream and support indefinitely. Dave suggested this as a temporary out-of-tree workaround until the majority of guest dhcp clients are fixed. Has anything changed that makes this course of action impractical? -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
On Friday 2010-07-09 17:17, Patrick McHardy wrote: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. I'm not sure this is something we want to merge upstream and support indefinitely. We could put it into Xtables-addons. That would also be consistent with Dave's suggestion. Dave suggested this as a temporary out-of-tree workaround until the majority of guest dhcp clients are fixed. Has anything changed that makes this course of action impractical? -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] netfilter: add CHECKSUM target
Am 09.07.2010 18:26, schrieb Jan Engelhardt: On Friday 2010-07-09 17:17, Patrick McHardy wrote: This adds a `CHECKSUM' target, which can be used in the iptables mangle table. You can use this target to compute and fill in the checksum in an IP packet that lacks a checksum. This is particularly useful, if you need to work around old applications such as dhcp clients, that do not work well with checksum offloads, but don't want to disable checksum offload in your device. I'm not sure this is something we want to merge upstream and support indefinitely. We could put it into Xtables-addons. That would also be consistent with Dave's suggestion. Sure, that would be fine with me. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH] netfilter: add CHECKSUM target
This adds a `CHECKSUM' target, which can be used in the iptables mangle
table.
You can use this target to compute and fill in the checksum in
an IP packet that lacks a checksum. This is particularly useful,
if you need to work around old applications such as dhcp clients,
that do not work well with checksum offloads, but don't want to
disable checksum offload in your device.
The problem happens in the field with virtualized applications.
For reference, see Red Hat bz 60, as well as
http://www.spinics.net/lists/kvm/msg37660.html
Typical expected use (helps old dhclient binary running in a VM):
iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM
--checksum-fill
Signed-off-by: Michael S. Tsirkin m...@redhat.com
---
Lightly tested. Please review for 2.6.36. Thanks!
include/linux/netfilter_ipv4/ipt_CHECKSUM.h | 18 +++
net/ipv4/netfilter/Kconfig | 16 ++
net/ipv4/netfilter/Makefile |1 +
net/ipv4/netfilter/ipt_CHECKSUM.c | 72 +++
4 files changed, 107 insertions(+), 0 deletions(-)
create mode 100644 include/linux/netfilter_ipv4/ipt_CHECKSUM.h
create mode 100644 net/ipv4/netfilter/ipt_CHECKSUM.c
diff --git a/include/linux/netfilter_ipv4/ipt_CHECKSUM.h
b/include/linux/netfilter_ipv4/ipt_CHECKSUM.h
new file mode 100644
index 000..0b0f660
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ipt_CHECKSUM.h
@@ -0,0 +1,18 @@
+/* Header file for iptables ipt_CHECKSUM target
+ *
+ * (C) 2002 by Harald Welte lafo...@gnumonks.org
+ * (C) 2010 Red Hat Inc
+ * Author: Michael S. Tsirkin m...@redhat.com
+ *
+ * This software is distributed under GNU GPL v2, 1991
+*/
+#ifndef _IPT_CHECKSUM_TARGET_H
+#define _IPT_CHECKSUM_TARGET_H
+
+#define IPT_CHECKSUM_OP_FILL 0x01/* fill in checksum in IPv4 header */
+
+struct ipt_CHECKSUM_info {
+ u_int8_t operation; /* bitset of operations */
+};
+
+#endif /* _IPT_CHECKSUM_TARGET_H */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 1833bdb..2fb979b 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -322,6 +322,22 @@ config IP_NF_TARGET_ECN
To compile it as a module, choose M here. If unsure, say N.
+config IP_NF_TARGET_CHECKSUM
+ tristate CHECKSUM target support
+ depends on IP_NF_MANGLE
+ depends on NETFILTER_ADVANCED
+ ---help---
+ This option adds a `CHECKSUM' target, which can be used in the
iptables mangle
+ table.
+
+ You can use this target to compute and fill in the checksum in
+ an IP packet that lacks a checksum. This is particularly useful,
+ if you need to work around old applications such as dhcp clients,
+ that do not work well with checksum offloads, but don't want to
disable
+ checksum offload in your device.
+
+ To compile it as a module, choose M here. If unsure, say N.
+
config IP_NF_TARGET_TTL
tristate 'TTL target support'
depends on NETFILTER_ADVANCED
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 4811159..d7047bb 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_IP_NF_MATCH_ECN) += ipt_ecn.o
# targets
obj-$(CONFIG_IP_NF_TARGET_CLUSTERIP) += ipt_CLUSTERIP.o
obj-$(CONFIG_IP_NF_TARGET_ECN) += ipt_ECN.o
+obj-$(CONFIG_IP_NF_TARGET_CHECKSUM) += ipt_CHECKSUM.o
obj-$(CONFIG_IP_NF_TARGET_LOG) += ipt_LOG.o
obj-$(CONFIG_IP_NF_TARGET_MASQUERADE) += ipt_MASQUERADE.o
obj-$(CONFIG_IP_NF_TARGET_NETMAP) += ipt_NETMAP.o
diff --git a/net/ipv4/netfilter/ipt_CHECKSUM.c
b/net/ipv4/netfilter/ipt_CHECKSUM.c
new file mode 100644
index 000..b8346a1
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_CHECKSUM.c
@@ -0,0 +1,72 @@
+/* iptables module for the IPv4 CHECKSUM
+ *
+ * (C) 2002 by Harald Welte lafo...@netfilter.org
+ * (C) 2010 Red Hat, Inc.
+ *
+ * Author: Michael S. Tsirkin m...@redhat.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+#define pr_fmt(fmt) KBUILD_MODNAME : fmt
+#include linux/in.h
+#include linux/module.h
+#include linux/skbuff.h
+#include linux/netdevice.h
+
+#include linux/netfilter/x_tables.h
+#include linux/netfilter_ipv4/ip_tables.h
+#include linux/netfilter_ipv4/ipt_CHECKSUM.h
+
+MODULE_LICENSE(GPL);
+MODULE_AUTHOR(Michael S. Tsirkin m...@redhat.com);
+MODULE_DESCRIPTION(Xtables: checksum modification);
+
+static unsigned int
+checksum_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+ if (skb-ip_summed == CHECKSUM_PARTIAL) {
+ skb_checksum_help(skb);
+ }
+
+ return XT_CONTINUE;
+}
+
+static int checksum_tg_check(const struct xt_tgchk_param *par)
+{
+ const struct ipt_CHECKSUM_info *einfo = par-targinfo;
+
+ if (einfo-operation ~IPT_CHECKSUM_OP_FILL) {
+
