lib/libnetlink: update rtnl_talk to support malloc buff at run time

[mirror_iproute2.git] / ip / iplink.c

diff --git a/ip/iplink.c b/ip/iplink.c
index 6a96ea9ff56a7f7694c267a1524d696c1225a16c..0daca3f9d476399e6d4ddd423bbfb83732a05a56 100644 (file)
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -249,19 +249,26 @@ static int nl_get_ll_addr_len(unsigned int dev_index)
                        .ifi_index = dev_index,
                }
        };
+       struct nlmsghdr *answer;
        struct rtattr *tb[IFLA_MAX+1];
 
-       if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0)
+       if (rtnl_talk(&rth, &req.n, &answer) < 0)
                return -1;
 
-       len = req.n.nlmsg_len - NLMSG_LENGTH(sizeof(req.i));
-       if (len < 0)
+       len = answer->nlmsg_len - NLMSG_LENGTH(sizeof(struct ifinfomsg));
+       if (len < 0) {
+               free(answer);
                return -1;
+       }
 
-       parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(&req.i), len, NLA_F_NESTED);
-       if (!tb[IFLA_ADDRESS])
+       parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)),
+                          len, NLA_F_NESTED);
+       if (!tb[IFLA_ADDRESS]) {
+               free(answer);
                return -1;
+       }
 
+       free(answer);
        return RTA_PAYLOAD(tb[IFLA_ADDRESS]);
 }
 
@@ -916,7 +923,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
 
                        req.i.ifi_index = 0;
                        addattr32(&req.n, sizeof(req), IFLA_GROUP, group);
-                       if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)
+                       if (rtnl_talk(&rth, &req.n, NULL) < 0)
                                return -2;
                        return 0;
                }
@@ -1006,7 +1013,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
                return -1;
        }
 
-       if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)
+       if (rtnl_talk(&rth, &req.n, NULL) < 0)
                return -2;
 
        return 0;
@@ -1020,10 +1027,7 @@ int iplink_get(unsigned int flags, char *name, __u32 filt_mask)
                .n.nlmsg_type = RTM_GETLINK,
                .i.ifi_family = preferred_family,
        };
-       struct {
-               struct nlmsghdr n;
-               char buf[32768];
-       } answer;
+       struct nlmsghdr *answer;
 
        if (name) {
                addattr_l(&req.n, sizeof(req),
@@ -1031,21 +1035,17 @@ int iplink_get(unsigned int flags, char *name, __u32 filt_mask)
        }
        addattr32(&req.n, sizeof(req), IFLA_EXT_MASK, filt_mask);
 
-       if (rtnl_talk(&rth, &req.n, &answer.n, sizeof(answer)) < 0)
-               return -2;
-       if (answer.n.nlmsg_len > sizeof(answer.buf)) {
-               fprintf(stderr, "Message truncated from %u to %lu\n",
-                       answer.n.nlmsg_len, sizeof(answer.buf));
+       if (rtnl_talk(&rth, &req.n, &answer) < 0)
                return -2;
-       }
 
        open_json_object(NULL);
        if (brief)
-               print_linkinfo_brief(NULL, &answer.n, stdout, NULL);
+               print_linkinfo_brief(NULL, answer, stdout, NULL);
        else
-               print_linkinfo(NULL, &answer.n, stdout);
+               print_linkinfo(NULL, answer, stdout);
        close_json_object();
 
+       free(answer);
        return 0;
 }