network work

1 files changed, 34 insertions, 0 deletions

diff --git a/src/firejail/network.c b/src/firejail/network.c
index 5f7a84a1e..ece406fc8 100644
--- a/src/firejail/network.c
+++ b/src/firejail/network.c
@@ -240,6 +240,40 @@ void net_if_up(const char *ifname) {
         close(sock);
 }
 
+// bring interface up
+void net_if_down(const char *ifname) {
+        if (strlen(ifname) > IFNAMSIZ) {
+                fprintf(stderr, "Error: invalid network device name %s\n", ifname);
+                exit(1);
+        }
+        
+        int sock = socket(AF_INET,SOCK_DGRAM,0);
+        if (sock < 0)
+                errExit("socket");
+
+        // get the existing interface flags
+        struct ifreq ifr;
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+        ifr.ifr_addr.sa_family = AF_INET;
+
+        // read the existing flags
+        if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0) {
+                close(sock);
+                errExit("ioctl");
+        }
+
+        ifr.ifr_flags &= ~IFF_UP;
+
+        // set the new flags
+        if (ioctl( sock, SIOCSIFFLAGS, &ifr ) < 0) {
+                close(sock);
+                errExit("ioctl");
+        }
+
+        close(sock);
+}
+
 // configure interface
 void net_if_ip(const char *ifname, uint32_t ip, uint32_t mask, int mtu) {
         if (strlen(ifname) > IFNAMSIZ) {