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extensions: libxt_connmark: Add translation to nft

PATCH Superseded Shivani Bhardwaj 2 participants 4 messages Dec 23, 2015 – Dec 28, 2015 netfilter

v3 of 4 Superseded Latest is v4 →

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Shivani Bhardwaj

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#0 lore raw

PATCH v3 1/1 extensions: libxt_connmark: Add translation to nft

Add translation for connmark to nftables.

Examples:

$ sudo iptables-translate -A INPUT -m connmark --mark 2 -j ACCEPT
nft add rule ip filter INPUT ct mark 0x2 counter accept
$ sudo iptables-translate -A INPUT -m connmark ! --mark 2 -j ACCEPT
nft add rule ip filter INPUT ct mark != 0x2 counter accept
$ sudo iptables-translate -A INPUT -m connmark --mark 10/10 -j ACCEPT
nft add rule ip filter INPUT ct mark and 0xa == 0xa counter accept
$ sudo iptables-translate -A INPUT -m connmark ! --mark 10/10 -j ACCEPT
nft add rule ip filter INPUT ct mark and 0xa != 0xa counter accept
$ sudo iptables-translate -t mangle -A PREROUTING -p tcp --dport 40 -m
connmark --mark 0x40
nft add rule ip mangle PREROUTING tcp dport 40 ct mark 0x40 counter
Signed-off-by Shivani Bhardwaj <[email protected]>

---
Changes in v3:
Replace the string added in v2 with enum to make code look better

 extensions/libxt_connmark.c | 47 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)
extensions/libxt_connmark.c +46 -1
index 95477de..087d4bf 100644
@@ -89,7 +89,8 @@ connmark_print(const void *ip, const struct xt_entry_match *match, int numeric)
 }
 
 static void
-connmark_mt_print(const void *ip, const struct xt_entry_match *match, int numeric)
+connmark_mt_print(const void *ip, const struct xt_entry_match *match,
+		  int numeric)
 {
 	const struct xt_connmark_mtinfo1 *info = (const void *)match->data;
 

@@ -122,6 +123,48 @@ connmark_mt_save(const void *ip, const struct xt_entry_match *match)
 	print_mark(info->mark, info->mask);
 }
 
+static void print_mark_xlate(unsigned int mark, unsigned int mask,
+			     struct xt_buf *buf, uint32_t op)
+{
+	if (mask != 0xffffffffU)
+		xt_buf_add(buf, " and 0x%x %s 0x%x ", mark,
+			   op == XT_OP_EQ ? "==" : "!=", mask);
+	else
+		xt_buf_add(buf, " %s0x%x ",
+			   op == XT_OP_EQ ? "" : "!= ", mark);
+}
+
+static int connmark_xlate(const struct xt_entry_match *match,
+			  struct xt_buf *buf, int numeric)
+{
+	const struct xt_connmark_info *info = (const void *)match->data;
+	enum xt_op op = XT_OP_EQ;
+
+	if (info->invert)
+		op = XT_OP_NEQ;
+
+	xt_buf_add(buf, "ct mark");
+	print_mark_xlate(info->mark, info->mask, buf, op);
+
+	return 1;
+}
+
+static int
+connmark_mt_xlate(const struct xt_entry_match *match,
+		 struct xt_buf *buf, int numeric)
+{
+	const struct xt_connmark_mtinfo1 *info = (const void *)match->data;
+	enum xt_op op = XT_OP_EQ;
+
+	if (info->invert)
+		op = XT_OP_NEQ;
+
+	xt_buf_add(buf, "ct mark");
+	print_mark_xlate(info->mark, info->mask, buf, op);
+
+	return 1;
+}
+
 static struct xtables_match connmark_mt_reg[] = {
 	{
 		.family        = NFPROTO_UNSPEC,

@@ -135,6 +178,7 @@ static struct xtables_match connmark_mt_reg[] = {
 		.save          = connmark_save,
 		.x6_parse      = connmark_parse,
 		.x6_options    = connmark_mt_opts,
+		.xlate	       = connmark_xlate,
 	},
 	{
 		.version       = XTABLES_VERSION,

@@ -148,6 +192,7 @@ static struct xtables_match connmark_mt_reg[] = {
 		.save          = connmark_mt_save,
 		.x6_parse      = connmark_mt_parse,
 		.x6_options    = connmark_mt_opts,
+		.xlate	       = connmark_mt_xlate,
 	},
 };
Signature · 1 line
1.9.1
maintainer
#1 lore raw
Quoted 12 lines · Shivani Bhardwaj

static struct xtables_match connmark_mt_reg[] = {

extensions/libxt_connmark.c +1 -0
 	{
 		.family        = NFPROTO_UNSPEC,

@@ -135,6 +178,7 @@ static struct xtables_match connmark_mt_reg[] = {
 		.save          = connmark_save,
 		.x6_parse      = connmark_parse,
 		.x6_options    = connmark_mt_opts,
+		.xlate	       = connmark_xlate,
 	},
 	{
 		.version       = XTABLES_VERSION,

extensions/libxt_connmark.c static struct xtables_match connmark_mt_reg[] = { · line 195

Quoted 4 lines
extensions/libxt_connmark.c +1 -0
@@ -148,6 +192,7 @@ static struct xtables_match connmark_mt_reg[] = {
 		.save          = connmark_mt_save,
 		.x6_parse      = connmark_mt_parse,
 		.x6_options    = connmark_mt_opts,
+		.xlate	       = connmark_mt_xlate,

Careful.

The different revisions use different structure definitions, ie. the structure binary layout is different, therefore you cannot reuse the same connmark_mt_xlate() for the two different revision.

Let me make sure I clarify this, this is revision 0:

struct xt_connmark_info {
        unsigned long mark, mask;
        uint8_t invert;
};

This is revision 1:

struct xt_connmark_mtinfo1 {
        __u32 mark, mask;
        __u8 invert;
};

The size of unsigned long depends on the architecture, so this code will not work correctly.

You have to add a connmark_mt_xlate_v0() and connmark_mt_xlate_v1(), in each of these functions you have to cast data to the right structure layout.

Thanks.

author
#2 lore raw
Quoted 38 lines · Pablo Neira Ayuso
Quoted 12 lines · Shivani Bhardwaj

static struct xtables_match connmark_mt_reg[] = {
{
.family = NFPROTO_UNSPEC,

extensions/libxt_connmark.c +1 -0
@@ -135,6 +178,7 @@ static struct xtables_match connmark_mt_reg[] = {
              .save          = connmark_save,
              .x6_parse      = connmark_parse,
              .x6_options    = connmark_mt_opts,
+             .xlate         = connmark_xlate,
      },
      {
              .version       = XTABLES_VERSION,

extensions/libxt_connmark.c static struct xtables_match connmark_mt_reg[] = { · line 195

Quoted 4 lines
extensions/libxt_connmark.c +1 -0
@@ -148,6 +192,7 @@ static struct xtables_match connmark_mt_reg[] = {
              .save          = connmark_mt_save,
              .x6_parse      = connmark_mt_parse,
              .x6_options    = connmark_mt_opts,
+             .xlate         = connmark_mt_xlate,

Careful.

The different revisions use different structure definitions, ie. the structure binary layout is different, therefore you cannot reuse the same connmark_mt_xlate() for the two different revision.

Let me make sure I clarify this, this is revision 0:

struct xt_connmark_info {
        unsigned long mark, mask;
        uint8_t invert;
};

This is revision 1:

struct xt_connmark_mtinfo1 {
        __u32 mark, mask;
        __u8 invert;
};
Quoted 8 lines

The size of unsigned long depends on the architecture, so this code will not work correctly.

You have to add a connmark_mt_xlate_v0() and connmark_mt_xlate_v1(), in each of these functions you have to cast data to the right structure layout.

Thanks.

Thanks for explaining. I understand it now but why is this patch wrong? I have used connmark_xlate() and connmark_mt_xlate() in their respective places. Do I still get it wrong?

I'm correcting this mistake for MARK.
Thank you

maintainer
#3 lore raw
Quoted 8 lines · Shivani Bhardwaj
Quoted 7 lines · Pablo Neira Ayuso

The size of unsigned long depends on the architecture, so this code will not work correctly.

You have to add a connmark_mt_xlate_v0() and connmark_mt_xlate_v1(), in each of these functions you have to cast data to the right structure layout.

Quoted 7 lines
Quoted 1 line

Thanks.

Thanks for explaining. I understand it now but why is this patch wrong? I have used connmark_xlate() and connmark_mt_xlate() in their respective places. Do I still get it wrong?

I'm correcting this mistake for MARK.

This patch correctly handles what I indicated above, but MARK is still wrong.

So I'm applying this patch, thanks.