ip link: Add support for kernel side filtering

Kernel gained support for filtering link dumps with commit dc599f76c22b
("net: Add support for filtering link dump by master device and kind").
Add support to ip link command. If a user passes master device or
kind to ip link command they are added to the link dump request message.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>

diff --git a/include/libnetlink.h b/include/libnetlink.h
index 491263f7e1039fc82ca1dc2986703d988e1030f8..f7b85dccef36f160872828891c06b46138b36e0d 100644 (file)
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -38,6 +38,12 @@ int rtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type)
 int rtnl_wilddump_req_filter(struct rtnl_handle *rth, int fam, int type,
                                    __u32 filt_mask)
        __attribute__((warn_unused_result));
+
+typedef int (*req_filter_fn_t)(struct nlmsghdr *nlh, int reqlen);
+
+int rtnl_wilddump_req_filter_fn(struct rtnl_handle *rth, int fam, int type,
+                               req_filter_fn_t fn)
+       __attribute__((warn_unused_result));
 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req,
                             int len)
        __attribute__((warn_unused_result));

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index aac7970e16dd71dd5d7cfbb249accceb8fbb58c6..0692fbacd6691e45b59c063365b7c19b0709cc82 100644 (file)
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -1476,6 +1476,36 @@ static int ipaddr_flush(void)
        return 1;
 }
 
+static int iplink_filter_req(struct nlmsghdr *nlh, int reqlen)
+{
+       int err;
+
+       err = addattr32(nlh, reqlen, IFLA_EXT_MASK, RTEXT_FILTER_VF);
+       if (err)
+               return err;
+
+       if (filter.master) {
+               err = addattr32(nlh, reqlen, IFLA_MASTER, filter.master);
+               if (err)
+                       return err;
+       }
+
+       if (filter.kind) {
+               struct rtattr *linkinfo;
+
+               linkinfo = addattr_nest(nlh, reqlen, IFLA_LINKINFO);
+
+               err = addattr_l(nlh, reqlen, IFLA_INFO_KIND, filter.kind,
+                               strlen(filter.kind));
+               if (err)
+                       return err;
+
+               addattr_nest_end(nlh, linkinfo);
+       }
+
+       return 0;
+}
+
 static int ipaddr_list_flush_or_save(int argc, char **argv, int action)
 {
        struct nlmsg_chain linfo = { NULL, NULL};
@@ -1638,7 +1668,8 @@ static int ipaddr_list_flush_or_save(int argc, char **argv, int action)
                exit(0);
        }
 
-       if (rtnl_wilddump_request(&rth, preferred_family, RTM_GETLINK) < 0) {
+       if (rtnl_wilddump_req_filter_fn(&rth, preferred_family, RTM_GETLINK,
+                                       iplink_filter_req) < 0) {
                perror("Cannot send dump request");
                exit(1);
        }

diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index a90e52ca2c0aa00d89dc570c0759e216cca2f671..0adcbf3f6e38960bfd093e8eae8c8ab0364903f3 100644 (file)
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -129,6 +129,34 @@ int rtnl_wilddump_req_filter(struct rtnl_handle *rth, int family, int type,
        return send(rth->fd, (void*)&req, sizeof(req), 0);
 }
 
+int rtnl_wilddump_req_filter_fn(struct rtnl_handle *rth, int family, int type,
+                               req_filter_fn_t filter_fn)
+{
+       struct {
+               struct nlmsghdr nlh;
+               struct ifinfomsg ifm;
+               char buf[1024];
+       } req;
+       int err;
+
+       if (!filter_fn)
+               return -EINVAL;
+
+       memset(&req, 0, sizeof(req));
+       req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+       req.nlh.nlmsg_type = type;
+       req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
+       req.nlh.nlmsg_pid = 0;
+       req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
+       req.ifm.ifi_family = family;
+
+       err = filter_fn(&req.nlh, sizeof(req));
+       if (err)
+               return err;
+
+       return send(rth->fd, (void*)&req, sizeof(req), 0);
+}
+
 int rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 {
        return send(rth->fd, buf, len, 0);