initial commit

This patch bootstrap the new nft-sync software. Basically, this
software aims to support two different setups:

1) Rule-set repository server. The software serves the nft rule-set to
   clients that request the ruleset.

   Basically from the system that acts as repository, you have to run:

   # nft-sync -c ../contrib/nft-sync.conf.server

   Then, from the client:

   # nft-sync -c ../contrib/nft-sync.conf.client --fetch

   Which displays the nft rule-set in the standard output, so you
   can inspect the nft rule-set.

   Alternatively, the client can also retrieve and apply the nft
   rule-set using the pull command instead:

   # nft-sync -c ../contrib/nft-sync.conf.client --pull

   [ Note that this command above does not work in this bootstrap yet ]

2) Rule-set synchronization: In case of primary-backup and multiprimary
   firewall configurations, the software makes sure that the firewall
   cluster is deploying the same filtering policy. In this case, you have
   to launch the process:

   # nft-sync -c ../contrib/nft-sync.conf --sync

   [ Note that this command above does not work in this bootstrap yet ]

This bootstrap provides the basic infrastructure as a proof-of-concept.
Many of the necessary features are still lacking:

* Implement --sync and --pull commands.

* Interaction with nft through libnftnl, which allows the software to
  retrieve the local nft rule-set, as well as to parse it and apply it.

* SSL support, specifically the repository mode needs it to make sure
  nobody can steal your filtering policy from the network.

* IPv6 support.

* Allow to serve different rule-sets in the repository mode.

And many others that will be added progressively.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/src/msg_buff.c b/src/msg_buff.c
new file mode 100644
index 0000000..c148516
--- /dev/null
+++ b/src/msg_buff.c
@@ -0,0 +1,96 @@
+/*
+ * (C) 2014 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include "msg_buff.h"
+
+struct msg_buff {
+	uint16_t		len;
+	unsigned char		*head;
+	unsigned char		*data;
+	unsigned char		*tail;
+	unsigned char		*end;
+
+	unsigned char		_data[0];
+};
+
+struct msg_buff *msgb_alloc(uint32_t size)
+{
+	struct msg_buff *msgb;
+
+	msgb = malloc(sizeof(struct msg_buff) + size);
+	if (msgb == NULL)
+		return NULL;
+
+	msgb->len = 0;
+	msgb->head = msgb->_data;
+	msgb->data = msgb->tail = msgb->_data;
+	msgb->end = msgb->_data + size;
+
+	return msgb;
+}
+
+void msgb_free(struct msg_buff *msgb)
+{
+	free(msgb);
+}
+
+uint32_t msgb_size(struct msg_buff *msgb)
+{
+	return msgb->end - msgb->head;
+}
+
+uint32_t msgb_len(struct msg_buff *msgb)
+{
+	return msgb->len;
+}
+
+void *msgb_put(struct msg_buff *msgb, uint32_t len)
+{
+	void *data = msgb->tail;
+
+	msgb->len += len;
+	msgb->tail += len;
+
+	return data;
+}
+
+void *msgb_pull(struct msg_buff *msgb, uint32_t len)
+{
+	void *ptr = msgb->data;
+
+	if (len > msgb->len)
+		return NULL;
+
+	msgb->len -= len;
+	msgb->data += len;
+
+	return ptr;
+}
+
+unsigned char *msgb_data(struct msg_buff *msgb)
+{
+	return msgb->data;
+}
+
+unsigned char *msgb_tail(struct msg_buff *msgb)
+{
+	return msgb->tail;
+}
+
+void msgb_burp(struct msg_buff *msgb)
+{
+	void *data = msgb->data;
+	int len = msgb->len;
+
+	msgb->data = msgb->head;
+	memcpy(msgb->data, data, len);
+}