examples: rtnl-route-add improvements (including IPv6 support)

Now, both IPv4 and IPv6 are supported simultaneously in one single file.

While at it:
* I moved the declarations to the beginning of the main function.
* Renamed mask by prefix, which seems more appropriate to me.
* Use RTPROTO_STATIC, as the route has been added by the administrator.
* Set NLM_F_ACK, so we get a report from the kernel about our query and
  treat reply from the kernel.
* Stricter argc checking.
* Use perror instead of printf for error reporting.

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

1 files changed, 57 insertions, 24 deletions

diff --git a/examples/rtnl/rtnl-route-add.c b/examples/rtnl/rtnl-route-add.c
index 6d166da..dd810c9 100644
--- a/examples/rtnl/rtnl-route-add.c
+++ b/examples/rtnl/rtnl-route-add.c
@@ -14,63 +14,83 @@
 
 int main(int argc, char *argv[])
 {
+	struct mnl_socket *nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	struct nlmsghdr *nlh;
+	struct rtmsg *rtm;
+	uint32_t prefix, seq, portid;
+	union {
+		in_addr_t ip;
+		struct in6_addr ip6;
+	} dst;
+	union {
+		in_addr_t ip;
+		struct in6_addr ip6;
+	} gw;
+	int iface, ret, family = AF_INET;
+
 	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]);
+		printf("	 %s eth0 ffff::10.0.1.12 128 fdff::1\n", argv[0]);
 		exit(EXIT_FAILURE);
 	}
 
-	int iface;
 	iface = if_nametoindex(argv[1]);
 	if (iface == 0) {
-		printf("Bad interface name\n");
+		perror("if_nametoindex");
 		exit(EXIT_FAILURE);
 	}
 
-	in_addr_t dst;
 	if (!inet_pton(AF_INET, argv[2], &dst)) {
-		printf("Bad destination\n");
-		exit(EXIT_FAILURE);
+		if (!inet_pton(AF_INET6, argv[2], &dst)) {
+			perror("inet_pton");
+			exit(EXIT_FAILURE);
+		}
+		family = AF_INET6;
 	}
 
-	uint32_t mask;
-	if (sscanf(argv[3], "%u", &mask) == 0) {
-		printf("Bad CIDR\n");
+	if (sscanf(argv[3], "%u", &prefix) == 0) {
+		perror("sscanf");
 		exit(EXIT_FAILURE);
 	}
 
-	in_addr_t gw;
-	if (argc >= 5 && !inet_pton(AF_INET, argv[4], &gw)) {
-		printf("Bad gateway\n");
+	if (argc == 5 && !inet_pton(family, argv[4], &gw)) {
+		perror("inet_pton");
 		exit(EXIT_FAILURE);
 	}
 
-	struct mnl_socket *nl;
-	char buf[MNL_SOCKET_BUFFER_SIZE];
-	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);
+	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
+	nlh->nlmsg_seq = 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_family = family;
+	rtm->rtm_dst_len = prefix;
 	rtm->rtm_src_len = 0;
 	rtm->rtm_tos = 0;
-	rtm->rtm_protocol = RTPROT_BOOT;
+	rtm->rtm_protocol = RTPROT_STATIC;
 	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);
+	if (family == AF_INET)
+		mnl_attr_put_u32(nlh, RTA_DST, dst.ip);
+	else
+		mnl_attr_put(nlh, RTA_DST, sizeof(struct in6_addr), &dst);
+
 	mnl_attr_put_u32(nlh, RTA_OIF, iface);
-	if (argc >= 5)
-		mnl_attr_put_u32(nlh, RTA_GATEWAY, gw);
+	if (argc == 5) {
+		if (family == AF_INET)
+			mnl_attr_put_u32(nlh, RTA_GATEWAY, gw.ip);
+		else {
+			mnl_attr_put(nlh, RTA_DST, sizeof(struct in6_addr),
+					&gw.ip6);
+		}
+	}
 
 	nl = mnl_socket_open(NETLINK_ROUTE);
 	if (nl == NULL) {
@@ -82,12 +102,25 @@ int main(int argc, char *argv[])
 		perror("mnl_socket_bind");
 		exit(EXIT_FAILURE);
 	}
+	portid = mnl_socket_get_portid(nl);
 
 	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 < 0) {
+		perror("mnl_socket_recvfrom");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);
+	if (ret < 0) {
+		perror("mnl_cb_run");
+		exit(EXIT_FAILURE);
+	}
+
 	mnl_socket_close(nl);
 
 	return 0;