Fix unsigned comparison error (#3174)

1 files changed, 10 insertions, 4 deletions

diff --git a/src/fnet/interface.c b/src/fnet/interface.c
index 6a9208898..62df0930e 100644
--- a/src/fnet/interface.c
+++ b/src/fnet/interface.c
@@ -375,9 +375,10 @@ void net_if_ip6(const char *ifname, const char *addr6) {
 
 static int net_netlink_address_tentative(struct nlmsghdr *current_header) {
         struct ifaddrmsg *msg = NLMSG_DATA(current_header);
+        int has_flags = 0;
+#ifdef IFA_FLAGS
         struct rtattr *rta = IFA_RTA(msg);
         size_t msg_len = IFA_PAYLOAD(current_header);
-        int has_flags = 0;
         while (RTA_OK(rta, msg_len)) {
                 if (rta->rta_type == IFA_FLAGS) {
                         has_flags = 1;
@@ -387,12 +388,13 @@ static int net_netlink_address_tentative(struct nlmsghdr *current_header) {
                 }
                 rta = RTA_NEXT(rta, msg_len);
         }
+#endif
         // According to <linux/if_addr.h>, if an IFA_FLAGS attribute is present,
         // the field ifa_flags should be ignored.
         return !has_flags && (msg->ifa_flags & IFA_F_TENTATIVE);
 }
 
-static int net_netlink_if_has_ll(int sock, int index) {
+static int net_netlink_if_has_ll(int sock, uint32_t index) {
         struct {
                 struct nlmsghdr header;
                 struct ifaddrmsg message;
@@ -412,7 +414,7 @@ static int net_netlink_if_has_ll(int sock, int index) {
                 ssize_t len = recv(sock, buf, sizeof(buf), 0);
                 if (len < 0)
                         errExit("recv");
-                if (len < sizeof(struct nlmsghdr)) {
+                if (len < (ssize_t) sizeof(struct nlmsghdr)) {
                         fprintf(stderr, "Received incomplete netlink message\n");
                         exit(1);
                 }
@@ -469,7 +471,11 @@ void net_if_waitll(const char *ifname) {
                 exit(1);
         }
         close(inet6_sock);
-        int index = ifr.ifr_ifindex;
+        if (ifr.ifr_ifindex < 0) {
+                fprintf(stderr, "Error fnet: interface index is negative\n");
+                exit(1);
+        }
+        uint32_t index = (uint32_t) ifr.ifr_ifindex;
 
         // poll for link-local address
         int netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);