examples: add nflog example

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

2 files changed, 233 insertions, 0 deletions

diff --git a/examples/netfilter/Makefile.am b/examples/netfilter/Makefile.am
index 927eb38..96466e0 100644
--- a/examples/netfilter/Makefile.am
+++ b/examples/netfilter/Makefile.am
@@ -1,10 +1,14 @@
 include $(top_srcdir)/Make_global.am
 
 check_PROGRAMS = nf-queue \
+		 nf-log \
 		 nfct-event
 
 nf_queue_SOURCES = nf-queue.c
 nf_queue_LDADD = ../../src/libmnl.la
 
+nf_log_SOURCES = nf-log.c
+nf_log_LDADD = ../../src/libmnl.la
+
 nfct_event_SOURCES = nfct-event.c
 nfct_event_LDADD = ../../src/libmnl.la
diff --git a/examples/netfilter/nf-log.c b/examples/netfilter/nf-log.c
new file mode 100644
index 0000000..8f0a877
--- /dev/null
+++ b/examples/netfilter/nf-log.c
@@ -0,0 +1,229 @@
+/*
+ * (C) 2010 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+
+#ifndef aligned_be64
+#define aligned_be64 u_int64_t __attribute__((aligned(8)))
+#endif
+
+#include <linux/netfilter/nfnetlink_log.h>
+
+static int parse_attr_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	/* skip unsupported attribute in user-space */
+	if (mnl_attr_type_valid(attr, NFULA_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFULA_MARK:
+	case NFULA_IFINDEX_INDEV:
+	case NFULA_IFINDEX_OUTDEV:
+	case NFULA_IFINDEX_PHYSINDEV:
+	case NFULA_IFINDEX_PHYSOUTDEV:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFULA_TIMESTAMP:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfulnl_msg_packet_timestamp)) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFULA_HWADDR:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfulnl_msg_packet_hw)) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFULA_PREFIX:
+		if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFULA_PAYLOAD:
+		break;
+	}
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static int log_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nlattr *tb[NFULA_MAX+1] = {};
+	struct nfulnl_msg_packet_hdr *ph = NULL;
+	const char *prefix = NULL;
+	uint32_t mark = 0;
+
+	mnl_attr_parse(nlh, sizeof(struct nfgenmsg), parse_attr_cb, tb);
+	if (tb[NFULA_PACKET_HDR])
+		ph = mnl_attr_get_payload(tb[NFULA_PACKET_HDR]);
+	if (tb[NFULA_PREFIX])
+		prefix = mnl_attr_get_str(tb[NFULA_PREFIX]);
+	if (tb[NFULA_MARK])
+		mark = ntohl(mnl_attr_get_u32(tb[NFULA_MARK]));
+
+	printf("log received (prefix=\"%s\" hw=0x%04x hook=%u mark=%u)\n",
+		prefix ? prefix : "", ntohs(ph->hw_protocol), ph->hook,
+		mark);
+
+	return MNL_CB_OK;
+}
+
+static struct nlmsghdr *
+nflog_build_cfg_pf_request(char *buf, uint8_t command)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_INET;
+	nfg->version = NFNETLINK_V0;
+
+	struct nfulnl_msg_config_cmd cmd = {
+		.command = command,
+	};
+	mnl_attr_put(nlh, NFULA_CFG_CMD, sizeof(cmd), &cmd);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nflog_build_cfg_request(char *buf, uint8_t command, int qnum)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_INET;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(qnum);
+
+	struct nfulnl_msg_config_cmd cmd = {
+		.command = command,
+	};
+	mnl_attr_put(nlh, NFULA_CFG_CMD, sizeof(cmd), &cmd);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nflog_build_cfg_params(char *buf, uint8_t mode, int range, int qnum)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(qnum);
+
+	struct nfulnl_msg_config_mode params = {
+		.copy_range = htonl(range),
+		.copy_mode = mode,
+	};
+	mnl_attr_put(nlh, NFULA_CFG_MODE, sizeof(params), &params);
+
+	return nlh;
+}
+
+int main(int argc, char *argv[])
+{
+	struct mnl_socket *nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	struct nlmsghdr *nlh;
+	int ret;
+	unsigned int portid, qnum;
+
+	if (argc != 2) {
+		printf("Usage: %s [queue_num]\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+	qnum = atoi(argv[1]);
+
+	nl = mnl_socket_open(NETLINK_NETFILTER);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		exit(EXIT_FAILURE);
+	}
+	portid = mnl_socket_get_portid(nl);
+
+	nlh = nflog_build_cfg_pf_request(buf, NFULNL_CFG_CMD_PF_UNBIND);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	nlh = nflog_build_cfg_pf_request(buf, NFULNL_CFG_CMD_PF_BIND);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	nlh = nflog_build_cfg_request(buf, NFULNL_CFG_CMD_BIND, qnum);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	nlh = nflog_build_cfg_params(buf, NFULNL_COPY_PACKET, 0xFFFF, qnum);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	if (ret == -1) {
+		perror("mnl_socket_recvfrom");
+		exit(EXIT_FAILURE);
+	}
+	while (ret > 0) {
+		ret = mnl_cb_run(buf, ret, 0, portid, log_cb, NULL);
+		if (ret < 0){
+			perror("mnl_cb_run");
+			exit(EXIT_FAILURE);
+		}
+
+		ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+		if (ret == -1) {
+			perror("mnl_socket_recvfrom");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	mnl_socket_close(nl);
+
+	return 0;
+}