[B.A.T.M.A.N.] [PATCHv3 next 1/3] batctl: introduce rtnl_open() helper function

Antonio Quartulli
2014-01-05T22:25:34Z

Other part of batctl may require to open and send
a message to RTNL. Extract this code and put it in
a generic helper to simplify future uses.

Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
---

Changes from v2:
- removed IFLA_NAME attribute from request (now we send the ifindex directly)
- improved rtnl_open()

Changes from v1:
- fixed typ0
- removed len argument from rtnl_open() in 1/3
- removed error messages in 2/3
- avoided double free in 2/3
- simplified 3/3

functions.c | 51 +++++++++++++++++++++++++++++++++++----------------
1 file changed, 35 insertions(+), 16 deletions(-)

diff --git a/functions.c b/functions.c
index 13ba190..33ca9ff 100644
--- a/functions.c
+++ b/functions.c
@@ -497,30 +497,28 @@ static void request_mac_resolve(int ai_family, const void *l3addr)
close(sock);
}

-static int resolve_mac_from_cache_open(int ai_family)
+/**
+ * rtnl_open - open a socket to rtnl and send a request
+ * @nh: the header of the request to send
+ * @protocol: the protocol to use when opening the socket
+ *
+ * Return 0 on success or a negative error code otherwise
+ */
+static int rtnl_open(void *req, int protocol)
{
- int socknl;
- int ret;
- struct {
- struct nlmsghdr hdr;
- struct ndmsg msg;
- } nlreq;
- struct sockaddr_nl addrnl;
static uint32_t nr_call = 0;
uint32_t pid = (++nr_call + getpid()) & 0x3FFFFF;
+ struct sockaddr_nl addrnl;
+ struct nlmsghdr *nh;
+ int socknl;
+ int ret;

memset(&addrnl, 0, sizeof(addrnl));
addrnl.nl_family = AF_NETLINK;
addrnl.nl_pid = pid;
addrnl.nl_groups = 0;

- memset(&nlreq, 0, sizeof(nlreq));
- nlreq.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(nlreq.msg));
- nlreq.hdr.nlmsg_type = RTM_GETNEIGH;
- nlreq.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
- nlreq.msg.ndm_family = ai_family;
-
- socknl = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+ socknl = socket(AF_NETLINK, SOCK_RAW, protocol);
if (socknl < 0)
goto out;

@@ -528,7 +526,12 @@ static int resolve_mac_from_cache_open(int ai_family)
if (ret < 0)
goto outclose;

- ret = send(socknl, &nlreq, nlreq.hdr.nlmsg_len, 0);
+ /* the nlmsghdr object must always be the first member in the req
+ * structure
+ */
+ nh = (struct nlmsghdr *)req;
+
+ ret = send(socknl, nh, nh->nlmsg_len, 0);
if (ret < 0)
goto outclose;
out:
@@ -538,6 +541,22 @@ outclose:
return ret;
}

+static int resolve_mac_from_cache_open(int ai_family)
+{
+ struct {
+ struct nlmsghdr hdr;
+ struct ndmsg msg;
+ } nlreq;
+
+ memset(&nlreq, 0, sizeof(nlreq));
+ nlreq.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(nlreq.msg));
+ nlreq.hdr.nlmsg_type = RTM_GETNEIGH;
+ nlreq.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ nlreq.msg.ndm_family = ai_family;
+
+ return rtnl_open(&nlreq, NETLINK_ROUTE);
+}
+
static ssize_t resolve_mac_from_cache_dump(int sock, void **buf, size_t *buflen)
{
struct iovec iov;
--
1.8.5.2