rtnl: update rtgenmsg to ifinfomsg when request link info

The previous function use general message and will dump all interfaces' information. Now update with ifinfomsg so we could get specific interface's information. We still could get all interfaces' info if set device to NULL. Signed-off-by: Hangbin Liu <[email protected]>
lmunch · Oct 14, 2017 · 05bba46 · 05bba46
1 parent 7e294a4
commit 05bba46
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Showing 3 changed files with 12 additions and 9 deletions.
diff --git a/port.c b/port.c
@@ -1512,7 +1512,7 @@ static int port_initialize(struct port *p)
 		if (p->fda.fd[FD_RTNL] == -1)
 			p->fda.fd[FD_RTNL] = rtnl_open();
 		if (p->fda.fd[FD_RTNL] >= 0)
-			rtnl_link_query(p->fda.fd[FD_RTNL]);
+			rtnl_link_query(p->fda.fd[FD_RTNL], p->iface->name);
 	}
 
 	port_nrate_initialize(p);

diff --git a/rtnl.c b/rtnl.c
@@ -42,7 +42,7 @@ int rtnl_close(int fd)
 	return close(fd);
 }
 
-int rtnl_link_query(int fd)
+int rtnl_link_query(int fd, char *device)
 {
 	struct sockaddr_nl sa;
 	struct msghdr msg;
@@ -51,19 +51,21 @@ int rtnl_link_query(int fd)
 
 	struct {
 		struct nlmsghdr hdr;
-		struct rtgenmsg gen;
+		struct ifinfomsg ifm;
 	} __attribute__((packed)) request;
 
 	memset(&sa, 0, sizeof(sa));
 	sa.nl_family = AF_NETLINK;
 
 	memset(&request, 0, sizeof(request));
-	request.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(request.gen));
+	request.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(request.ifm));
 	request.hdr.nlmsg_type = RTM_GETLINK;
-	request.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+	request.hdr.nlmsg_flags = NLM_F_REQUEST;
 	request.hdr.nlmsg_seq = 1;
 	request.hdr.nlmsg_pid = 0;
-	request.gen.rtgen_family = AF_UNSPEC;
+	request.ifm.ifi_family = AF_UNSPEC;
+	request.ifm.ifi_index = if_nametoindex(device ? device : "");
+	request.ifm.ifi_change = 0xffffffff;
 
 	iov.iov_base = &request;
 	iov.iov_len = sizeof(request);

diff --git a/rtnl.h b/rtnl.h
@@ -31,10 +31,11 @@ int rtnl_close(int fd);
 
 /**
  * Request the link status from the kernel.
- * @param fd  A socket obtained via rtnl_open().
- * @return    Zero on success, non-zero otherwise.
+ * @param fd     A socket obtained via rtnl_open().
+ * @param device Interface name. Request all iface's status if set NULL.
+ * @return       Zero on success, non-zero otherwise.
  */
-int rtnl_link_query(int fd);
+int rtnl_link_query(int fd, char *device);
 
 /**
  * Read kernel messages looking for a link up/down events.