[PATCH libnetfilter_queue 0/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[PATCH libnetfilter_queue 0/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[Duncan Roe]

This is the first in what I expect will be a number of patches to
examples/nf-queue.c as I update the documentation and maybe introduce new
helper functions.
An aspirational goal is to have all netfilter functions in nf-queue.c be
documented in the libnetfilter_queue web page.

Duncan Roe (1):
  src: Comment-out code not needed since Linux 3.8 in
    examples/nf-queue.c

 examples/nf-queue.c | 48 +++++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

-- 
2.14.5

[PATCH libnetfilter_queue 1/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[Duncan Roe]

This makes it clear which lines are no longer required.
It also obviates the need to document NFQNL_CFG_CMD_PF_(UN)BIND.

Add comment with sed command to re-enable commented-out code.

Use // comments because my sed-fu is not up to reversing a /* comment block

Signed-off-by: Duncan Roe <duncan_roe@optusnet.com.au>
---
 examples/nf-queue.c | 48 +++++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

diff --git a/examples/nf-queue.c b/examples/nf-queue.c
index f6d254a..ee9e4f4 100644
--- a/examples/nf-queue.c
+++ b/examples/nf-queue.c
@@ -151,29 +151,31 @@ int main(int argc, char *argv[])
 	}
 
 	/* PF_(UN)BIND is not needed with kernels 3.8 and later */
-	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
-	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_UNBIND);
-
-	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
-		perror("mnl_socket_send");
-		exit(EXIT_FAILURE);
-	}
-
-	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
-	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_BIND);
-
-	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
-		perror("mnl_socket_send");
-		exit(EXIT_FAILURE);
-	}
-
-	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num);
-	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_BIND);
-
-	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
-		perror("mnl_socket_send");
-		exit(EXIT_FAILURE);
-	}
+	/* Uncomment this code block if you need to cater for an older kernel */
+	/* E.g. sed -i '156,178s+//++' examples/nf-queue.c */
+	//nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
+	//nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_UNBIND);
+	//
+	//if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+	//	perror("mnl_socket_send");
+	//	exit(EXIT_FAILURE);
+	//}
+	//
+	//nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
+	//nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_BIND);
+	//
+	//if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+	//	perror("mnl_socket_send");
+	//	exit(EXIT_FAILURE);
+	//}
+	//
+	//nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num);
+	//nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_BIND);
+	//
+	//if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+	//	perror("mnl_socket_send");
+	//	exit(EXIT_FAILURE);
+	//}
 
 	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num);
 	nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff);
-- 
2.14.5

Re: [PATCH libnetfilter_queue 1/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[Florian Westphal]

Duncan Roe <duncan_roe@optusnet.com.au> wrote:
> This makes it clear which lines are no longer required.
> It also obviates the need to document NFQNL_CFG_CMD_PF_(UN)BIND.

Why not simply #if 0 this code?

Or just delete it, v3.8 was released almost 7 years ago.

Re: [PATCH libnetfilter_queue 1/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[Duncan Roe]

Hi Floerian,

On Sun, Nov 24, 2019 at 03:45:47PM +0100, Florian Westphal wrote:
> Duncan Roe <duncan_roe@optusnet.com.au> wrote:
> > This makes it clear which lines are no longer required.
> > It also obviates the need to document NFQNL_CFG_CMD_PF_(UN)BIND.
>
> Why not simply #if 0 this code?

Simple reason: I think it's important to have an indicator on each commented-out
line that it is,in fact, commented-out.
>
> Or just delete it, v3.8 was released almost 7 years ago.

I could do that. But, I'm uneasy about it. There are systems around with very
old Linuxes - in May last year there was that Tomato Firmware non-issue and the
embedded environment was at 2.6!

Your call (or Pablo's) - I'm happy either way.

Cheers ... Duncan.

On Sun, 27 May 2018 01:02:46 -0400, Edriss Mirzadeh wrote:
> Hi there,
>
> I???m actually cross compiling Tomato Firmware using 64 bit Debian 9.
>
> The build instructions are good at the below URL, except for the repo name
> which recently changed but hasn???t yet been updated in the readme
> instructions.
>
> https://bitbucket.org/kille72/freshtomato-arm/src
>
> This could well be due to either the cross-compilation or the very old tool
> chain, or ancient kernel 2.6 (with many back ports), but I do agree that
> local headers should be double quoted, so your thought on patch rings true
> in terms of portability.
>
> Cheers!

Re: [PATCH libnetfilter_queue 1/1] src: Comment-out code not needed since Linux 3.8 in examples/nf-queue.c

[Pablo Neira Ayuso]

On Mon, Nov 25, 2019 at 10:52:40AM +1100, Duncan Roe wrote:
> Hi Floerian,
> 
> On Sun, Nov 24, 2019 at 03:45:47PM +0100, Florian Westphal wrote:
> > Duncan Roe <duncan_roe@optusnet.com.au> wrote:
> > > This makes it clear which lines are no longer required.
> > > It also obviates the need to document NFQNL_CFG_CMD_PF_(UN)BIND.
> >
> > Why not simply #if 0 this code?
> 
> Simple reason: I think it's important to have an indicator on each commented-out
> line that it is,in fact, commented-out.
> >
> > Or just delete it, v3.8 was released almost 7 years ago.
> 
> I could do that. But, I'm uneasy about it. There are systems around with very
> old Linuxes - in May last year there was that Tomato Firmware non-issue and the
> embedded environment was at 2.6!
> 
> Your call (or Pablo's) - I'm happy either way.

I think it's fine to remove it.

There will be a commit message describing this is only required by
very old kernel, which should be good enough for people with exotic
environments to catch up I would expect.

Thanks.

[PATCH libnetfilter_queue v2] src: Delete code not needed since Linux 3.8 in examples/nf-queue.c

[Duncan Roe]

The removed code sent configuration commands NFQNL_CFG_CMD_PF_UNBIND &
NFQNL_CFG_CMD_PF_BIND which the kernel required prior to 3.8.

Signed-off-by: Duncan Roe <duncan_roe@optusnet.com.au>
---
 examples/nf-queue.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/examples/nf-queue.c b/examples/nf-queue.c
index f6d254a..960e244 100644
--- a/examples/nf-queue.c
+++ b/examples/nf-queue.c
@@ -150,23 +150,6 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
-	/* PF_(UN)BIND is not needed with kernels 3.8 and later */
-	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
-	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_UNBIND);
-
-	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
-		perror("mnl_socket_send");
-		exit(EXIT_FAILURE);
-	}
-
-	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0);
-	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_BIND);
-
-	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
-		perror("mnl_socket_send");
-		exit(EXIT_FAILURE);
-	}
-
 	nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num);
 	nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_BIND);
 
-- 
2.14.5

Re: [PATCH libnetfilter_queue v2] src: Delete code not needed since Linux 3.8 in examples/nf-queue.c

[Pablo Neira Ayuso]

On Tue, Nov 26, 2019 at 09:25:46PM +1100, Duncan Roe wrote:
> The removed code sent configuration commands NFQNL_CFG_CMD_PF_UNBIND &
> NFQNL_CFG_CMD_PF_BIND which the kernel required prior to 3.8.

Applied, thanks.