add rtnl-route-add.c to examples

Heavily based on an example from Alejandro Castaño. Untested.

Signed-off-by: Alejandro Castaño <alecastanyo@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 98 insertions, 0 deletions

diff --git a/examples/Makefile.am b/examples/Makefile.am
index 1874971..8102d2f 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -3,6 +3,7 @@ include $(top_srcdir)/Make_global.am
 check_PROGRAMS = rtnl-link-dump rtnl-link-dump2 rtnl-link-dump3 \
 		 rtnl-link-event \
 		 rtnl-link-set \
+		 rtnl-route-add \
 		 rtnl-route-dump \
 		 genl-family-get
 
@@ -18,6 +19,10 @@ rtnl_link_dump3_SOURCES = rtnl-link-dump3.c
 rtnl_link_dump3_LDADD = ../src/libmnl.la
 rtnl_link_dump3_LDFLAGS = -dynamic -ldl
 
+rtnl_route_add_SOURCES = rtnl-route-add.c
+rtnl_route_add_LDADD = ../src/libmnl.la
+rtnl_route_add_LDFLAGS = -dynamic -ldl
+
 rtnl_link_event_SOURCES = rtnl-link-event.c
 rtnl_link_event_LDADD = ../src/libmnl.la
 rtnl_link_event_LDFLAGS = -dynamic -ldl
diff --git a/examples/rtnl-route-add.c b/examples/rtnl-route-add.c
new file mode 100644
index 0000000..81c508f
--- /dev/null
+++ b/examples/rtnl-route-add.c
@@ -0,0 +1,93 @@
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <strings.h>
+#include <net/if.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
+int main(int argc, char *argv[])
+{
+	if (argc <= 3) {
+		printf("Usage: %s iface destination cidr [gateway]\n", argv[0]);
+		printf("Example: %s eth0 10.0.1.12 32 10.0.1.11\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	int iface;
+	iface = if_nametoindex(argv[1]);
+	if (iface == 0) {
+		printf("Bad interface name\n");
+		exit(EXIT_FAILURE);
+	}
+
+	in_addr_t dst;
+	if (!inet_pton(AF_INET, argv[2], &dst)) {
+		printf("Bad destination\n");
+		exit(EXIT_FAILURE);
+	}
+
+	uint32_t mask;
+	if (sscanf(argv[3], "%u", &mask) == 0) {
+		printf("Bad CIDR\n");
+		exit(EXIT_FAILURE);
+	}
+
+	in_addr_t gw;
+	if (argc >= 5 && !inet_pton(AF_INET, argv[4], &gw)) {
+		printf("Bad gateway\n");
+		exit(EXIT_FAILURE);
+	}
+
+	struct mnl_socket *nl;
+	char buf[getpagesize()];
+	struct nlmsghdr *nlh;
+	struct rtmsg *rtm;
+
+	nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type	= RTM_NEWROUTE;
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
+	nlh->nlmsg_seq = time(NULL);
+
+	rtm = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtmsg));
+	rtm->rtm_family = AF_INET;
+	rtm->rtm_dst_len = mask;
+	rtm->rtm_src_len = 0;
+	rtm->rtm_tos = 0;
+	rtm->rtm_protocol = RTPROT_BOOT;
+	rtm->rtm_table = RT_TABLE_MAIN;
+	rtm->rtm_type = RTN_UNICAST;
+	/* is there any gateway? */
+	rtm->rtm_scope = (argc == 4) ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
+	rtm->rtm_flags = 0;
+
+	mnl_attr_put_u32(nlh, RTA_DST, dst);
+	mnl_attr_put_u32(nlh, RTA_OIF, iface);
+	if (argc >= 5)
+		mnl_attr_put_u32(nlh, RTA_GATEWAY, gw);
+
+	nl = mnl_socket_open(NETLINK_ROUTE);
+	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);
+	}
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	mnl_socket_close(nl);
+
+	return 0;
+}